Signaling Analysis Manual

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Chapter 3 System Information 3-1........................................................................

3.1 Overview 3-1................................................................................................

3.2 Detailed Description of System Information 3-2...........................................

3.2.1 SYSTEM INFORMATION TYPE 1 3-2.................................................3.2.2 SYSTEM INFORMATION TYPE 2, 2bis and 2ter 3-5..........................

3.2.3 SYSTEM INFORMATION TYPE 3 3-7.................................................


3.2.5 System Information type 5, 5bis & 5ter 3-12..........................................




3.3 Internal Handling of BSC 3-14........................................................................

Chapter 4 Location Update Procedure 4-1..........................................................

4.1 Overview 4-1................................................................................................

4.2 Location Updating Procedure 4-2.................................................................

4.2.1 Periodic Updating 4-3...........................................................................

4.2.2 IMSI Attach Procedure 4-4...................................................................

4.2.3 Generic Location Updating Procedure 4-4...........................................


Chapter 5 Authentication Procedure 5-1.............................................................

5.1 Overview 5-1................................................................................................

5.2 Authentication Procedure 5-1.......................................................................

5.2.1 Successful Authentication 5-2..............................................................

5.2.2 Unsuccessful Authentication 5-2..........................................................


5.4 Abnormal Cases 5-4.....................................................................................

5.4.1 RR Connection Failure 5-4...................................................................

5.4.2 Expiry of Timer T3260 5-4....................................................................

5.4.3 SIM Unregistered 5-4...........................................................................Chapter 6 Release Procedure 6-1.........................................................................

6.1 Overview 6-1................................................................................................

6.2 Normal Release Procedure 6-1....................................................................

6.3 BSC Local Release Procedure 6-3...............................................................


Chapter 7 Mobile Originating Call Establishment Procedure 7-1......................

7.1 Overview 7-1................................................................................................

7.2 Normal Procedure 7-1..................................................................................



7.2.1 Mobile Originating Call Establishment without OACSU (EarlyAssignment) 7-1............................................................................................

7.2.2 Mobile Originating Call Establishment with OACSU (LateAssignment) 7-6............................................................................................

7.2.3 Mobile Originating Call Establishment with OACSU (Very EarlyAssignment) 7-8............................................................................................


7.4 Abnormal Cases 7-9.....................................................................................

7.4.1 Abnormal Random Access/Immediate Assignment Procedure 7-10.....

7.4.2 MSC Directly Delivers DISCONNECT to Clear the Call, Insteadof Delivering the Assignment Request 7-11....................................................

7.4.3 Abnormal Assignment Procedure 7-11..................................................

7.4.4 Abnormal Procedure Cause by Call Interruption 7-12...........................

7.4.5 Abnormal Procedure Caused by Hangup 7-12......................................

7.4.6 Abnormal Procedure Caused by MSC Clearing 7-13............................

Chapter 8 Mobile Terminating Call Establishment Procedure 8-1....................

8.1 Overview 8-1................................................................................................



8.4 Abnormal Cases 8-3.....................................................................................

8.4.1 No PAGING COMMAND on Interface A 8-4........................................

8.4.2 No PAGING COMMAND on Interface Abis 8-4...................................

8.4.3 No PAGING RESPONSE on Interface Abis 8-5..................................

8.4.4 No PAGING RESPONSE on Interface A 8-7.......................................

Chapter 9 Handover Procedure 9-1......................................................................

9.1 Overview 9-1................................................................................................


9.2.1 Intra-BSC Handover Procedure 9-1.....................................................

9.2.2 Inter-BSC Handover Procedure 9-4.....................................................

9.2.3 Inter-MSC Handover Procedure 9-6....................................................

9.3 Abnormal Cases 9-7.....................................................................................9.3.1 Handover Failure Due to CIC Exception 9-7........................................

9.3.2 Handover Failure Due to MS Access Failure 9-7.................................

9.3.3 Handover Procedure Initiation Failure 9-8...........................................

Chapter 10 Ciphering Mode Setting Procedure 10-1............................................

10.1 Overview 10-1..............................................................................................

10.2 Normal Procedure 10-1................................................................................

10.3 Internal Handling of BSC 10-2......................................................................

10.4 Abnormal Cases 10-3...................................................................................10.4.1 Ciphering Rejected 10-3......................................................................



10.4.2 MS Not Ciphered 10-3.........................................................................

Chapter 11 Call Re-establishment Procedure 11-1...............................................

11.1 Overview 11-1..............................................................................................

11.2 Normal Procedure 11-1................................................................................11.3 Abnormal Cases 11-3...................................................................................

11.3.1 CM Service Rejected 11-3...................................................................

11.3.2 Re-establishment Not Allowed or Re-establishment Failure 11-4........

11.3.3 RR Connection Failure 11-4.................................................................

Chapter 12 Directed Retry Procedure 12-1............................................................

12.1 Overview 12-1..............................................................................................


12.2.1 Directed Retry Intra-BSC Handover Procedure 12-2...........................12.2.2 Directed Retry Inter-BSC Handover Procedure 12-5...........................

12.2.3 Directed Retry Inter-MSC Handover Procedure 12-7..........................

12.3 Abnormal Cases 12-8...................................................................................

Chapter 13 Short Message Procedure 13-1...........................................................

13.1 Overview 13-1..............................................................................................


13.2.1 Short Message Procedure on SDCCH When MS Is Calling 13-2........

13.2.2 Short Message Procedure on SDCCH When MS Is Called 13-4.........

13.2.3 Short Message Procedure on SACCH When MS Is Calling 13-6........

13.3 Short Message Procedure on SACCH when MS Is Called 13-7..................

13.4 Internal Handling of BSC 13-7......................................................................

13.5 Abnormal Cases 13-8...................................................................................

Chapter 14 Cell Broadcast Message Procedure 14-1...........................................

14.1 Overview 14-1..............................................................................................

14.2 CBC-BSC Interface Message Procedure 14-1.............................................

14.3 Messages and Service Functions over the Interface between BSC

and BTS 14-5.......................................................................................................14.4 Internal Handling of BSC 14-5......................................................................

14.5 Abnormal Cases 14-6...................................................................................

Appendix A Message Interpretation A-1..............................................................

A.1 A-Interface Key Messages A-1.....................................................................

A.1.1 Message Contents A-2.........................................................................

A.1.2 Signaling element coding A-15..............................................................

A.1.3 Message Type A-18...............................................................................

A.2 Abis-Interface Key Messages A-62................................................................A.2.1 Message Contents A-62.........................................................................



A.2.2 Signaling element coding A-69..............................................................

Appendix B Difference between Phase1- Phase2- Phase2+ B-1.......................

B.1 Difference between Messages over A-interface in Different Phases B-1.....

B.2 Difference Analysis B-1................................................................................

Appendix C Glossary C-1......................................................................................

Appendix D Abbreviation D-1................................................................................

Appendix E Reference for GSM Protocols E-1....................................................



HUAWEI

M900/M1800 Base Station Subsystem

Signaling Analysis Manual

V300R002



M900/M1800 Base Station Subsystem

Signaling Analysis Manual

Manual Version T2-030302-20040420-C-4.02

Product Version V300R002

BOM 31033202

Huawei Technologies Co., Ltd. provides customers with comprehensive technical support

and service. Please feel free to contact our local office, customer care center or company

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Address: Administration Building, Huawei Technologies Co., Ltd.,

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Notice

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has been made in the preparation of this document to ensure accuracy of the

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About This Manual

Version

The product version that corresponds to the manual is M900/M1800 Base Station

Subsystem V300R002.

Organization of the Manual

This manual introduces the interface signaling tracing operations in BSC Maintenance

System and BSS signaling procedures. It comprises 14 chapters and 2 appendices.

The contents of each part are approximately as follows.

Chapter 1 Signaling Fundamentals introduces the major interface protocols and

functions of BSS, such as A interface, Abis interface and Um interface.

Chapter 2 Signaling Tracing Guide: introduces how to use the interface signaling

tracing tools of BSC Maintenance System.

Chapter 3 System Information: interprets in detail BSS system information.

Chapter 4 Location Update Procedure: describes in detail the location updating

procedure.

Chapter 5 Authentication Procedure: describes in detail the authentication

procedure.

Chapter 6 Release Procedure: describes in detail the release procedure.

Chapter 7 Mobile Originating Call Establishment Procedure: introduces in detail

the mobile originating call establishment procedure.

Chapter 8 Mobile Terminating Call Establishment Procedure: introduces in detail

the mobile terminating call establishment procedure.

Chapter 9 Handover Procedure: introduces in detail the handover procedure.

Chapter 10 Ciphering Mode Setting Procedure: introduces in detail the ciphering

mode setting procedure.

Chapter 11 Call Reestablishment Procedure: introduces in detail the call

reestablishment procedure.

Chapter 12 Direct Retry Procedure: introduces in detail the directed retry procedure.



Chapter 13 Short Message Procedure: introduces in detail the short message

procedure.

Chapter 14 Cell Broadcast Procedure: introduces in detail the cell broadcast

procedure.

Appendix A Message Interpretation: interprets in detail the messages in the

signaling procedures.

Appendix B Difference between Messages over A Interface in Different Phases:

describes the protocol differences between Phase1, Phase2 and Phase2.

Appendix C Glossary: lists all glossaries in the book.

Appendix D Abbreviation: lists all word abbreviations in the call procedures.

Appendix E Reference for GSM Protocols: lists the serial numbers and short title of all GSM protocols and helps users to quickly find the needed protocol(s).

Chapter 1 and Chapter 2 provide the basis for signaling tracing and analysis. Chapter 3

to Chapter 14 are the major points for signaling analysis and problem analysis as per

the signaling procedures.

Target Readers

This manual is suitable for the following readers.

z GSM network engineering staff

z BSS maintenance staff

z GSM system engineers

Conventions

This document uses the following conventions:

I. General conventions

Convention Description

Arial Normal paragraphs are in Arial.

Arial Narrow Warnings, cautions, notes and tips are in Arial Narrow.

II. Symbols

Eye-catching symbols are also used in this document to highlight the points worthy of

special attention during the operation. They are defined as follows:



Caution, Warning, Danger : Means reader be extremely careful during the

operation.

Note, Comment, Tip, Knowhow, Thought: Means a complementary description.



Signaling Analysis ManualM900/M1800 Base Station Subsystem Table of Contents

i

Table of Contents

Chapter 1 Signaling Fundamentals ............................................................................................. 1-1 1.1 Interface Overview............................................................................................................. 1-1 1.2 A-Interface ......................................................................................................................... 1-2

1.2.1 Overview ................................................................................................................. 1-2 1.2.2 Protocols on the A-Interface.................................................................................... 1-3

1.3 Abis interface ................................................................................................................... 1-10 1.3.1 Overview ............................................................................................................... 1-10 1.3.2 Protocols on the Abis Interface ............................................................................. 1-13

1.4 Um Interface .................................................................................................................... 1-20 1.4.1 Overview ............................................................................................................... 1-20 1.4.2 Layer 1 - Physical Layer........................................................................................ 1-21 1.4.3 Layer 2 - Data Link Layer...................................................................................... 1-22 1.4.4 L3 .......................................................................................................................... 1-23

Chapter 2 Signaling Trace Guide................................................................................................. 2-1 2.1 Overview............................................................................................................................ 2-1 2.2 Um Interface Trace............................................................................................................ 2-2

2.2.1 Functions................................................................................................................. 2-2 2.2.2 Operations............................................................................................................... 2-2 2.2.3 Options.................................................................................................................... 2-4 2.2.4 Examples................................................................................................................. 2-5

2.3 Abis Interface Trace........................................................................................................... 2-5 2.3.1 Functions................................................................................................................. 2-5 2.3.2 Operations............................................................................................................... 2-5 2.3.3 Options.................................................................................................................... 2-7 2.3.4 Examples................................................................................................................. 2-8

2.4 A Interface Trace ............................................................................................................. 2-10 2.4.1 Functions............................................................................................................... 2-10 2.4.2 Operations............................................................................................................. 2-10 2.4.3 Options.................................................................................................................. 2-14 2.4.4 Examples............................................................................................................... 2-14

2.5 SS7 Trace........................................................................................................................ 2-16 2.5.1 Functions............................................................................................................... 2-16 2.5.2 Operation and Options .......................................................................................... 2-18 2.5.3 Examples............................................................................................................... 2-22

2.6 SCCP Signaling Trace..................................................................................................... 2-24 2.6.1 Functions............................................................................................................... 2-24 2.6.2 Operations............................................................................................................. 2-25




ii

2.6.3 Options.................................................................................................................. 2-28 2.6.4 Examples............................................................................................................... 2-28

Chapter 3 System Information ..................................................................................................... 3-1 3.1 Overview............................................................................................................................ 3-1 3.2 Detailed Description of System Information ...................................................................... 3-2

3.2.1 SYSTEM INFORMATION TYPE 1.......................................................................... 3-2 3.2.2 SYSTEM INFORMATION TYPE 2, 2bis and 2ter................................................... 3-5 3.2.3 SYSTEM INFORMATION TYPE 3.......................................................................... 3-7 3.2.4 SYSTEM INFORMATION TYPE 4........................................................................ 3-10 3.2.5 System Information type 5, 5bis & 5ter ................................................................. 3-12 3.2.6 SYSTEM INFORMATION TYPE 6........................................................................ 3-13 3.2.7 SYSTEM INFORMATION TYPE 7........................................................................ 3-14 3.2.8 SYSTEM INFORMATION TYPE 8........................................................................ 3-14

3.3 Internal Handling of BSC ................................................................................................. 3-14 Chapter 4 Location Update Procedure........................................................................................ 4-1

4.1 Overview............................................................................................................................ 4-1 4.2 Location Updating Procedure............................................................................................ 4-2

4.2.1 Periodic Updating.................................................................................................... 4-3 4.2.2 IMSI Attach Procedure ............................................................................................ 4-4 4.2.3 Generic Location Updating Procedure.................................................................... 4-4

4.3 Internal Handling of BSC ...................................................................................................4-9 Chapter 5 Authentication Procedure........................................................................................... 5-1

5.1 Overview............................................................................................................................ 5-1 5.2 Authentication Procedure .................................................................................................. 5-1

5.2.1 Successful Authentication ....................................................................................... 5-2 5.2.2 Unsuccessful Authentication................................................................................... 5-2

5.3 Internal Handling of BSC ...................................................................................................5-3 5.4 Abnormal Cases ................................................................................................................ 5-4

5.4.1 RR Connection Failure............................................................................................ 5-4 5.4.2 Expiry of Timer T3260............................................................................................. 5-4 5.4.3 SIM Unregistered .................................................................................................... 5-4

Chapter 6 Release Procedure ...................................................................................................... 6-1 6.1 Overview............................................................................................................................ 6-1 6.2 Normal Release Procedure ............................................................................................... 6-1 6.3 BSC Local Release Procedure.......................................................................................... 6-3 6.4 Internal Handling of BSC ...................................................................................................6-3

Chapter 7 Mobile Originating Call Establishment Procedure................................................... 7-1 7.1 Overview............................................................................................................................ 7-1 7.2 Normal Procedure.............................................................................................................. 7-1

7.2.1 Mobile Originating Call Establishment without OACSU (Early Assignment) .......... 7-1 7.2.2 Mobile Originating Call Establishment with OACSU (Late Assignment)................. 7-6




iii

7.2.3 Mobile Originating Call Establishment with OACSU (Very Early Assignment)....... 7-8 7.3 Internal Handling of BSC ...................................................................................................7-9 7.4 Abnormal Cases ................................................................................................................ 7-9

7.4.1 Abnormal Random Access/Immediate Assignment Procedure............................ 7-10

7.4.2 MSC Directly Delivers DISCONNECT to Clear the Call, Instead of Delivering the

Assignment Request ...................................................................................................... 7-11 7.4.3 Abnormal Assignment Procedure ......................................................................... 7-11 7.4.4 Abnormal Procedure Cause by Call Interruption .................................................. 7-12 7.4.5 Abnormal Procedure Caused by Hangup ............................................................. 7-12 7.4.6 Abnormal Procedure Caused by MSC Clearing ................................................... 7-13

Chapter 8 Mobile Terminating Call Establishment Procedure ................................................. 8-1 8.1 Overview............................................................................................................................ 8-1 8.2 Normal Procedure.............................................................................................................. 8-2 8.3 Internal Handling of BSC ...................................................................................................8-3 8.4 Abnormal Cases ................................................................................................................ 8-3

8.4.1 No PAGING COMMAND on Interface A................................................................. 8-4 8.4.2 No PAGING COMMAND on Interface Abis ............................................................ 8-4 8.4.3 No PAGING RESPONSE on Interface Abis ........................................................... 8-5 8.4.4 No PAGING RESPONSE on Interface A................................................................ 8-7

Chapter 9 Handover Procedure ................................................................................................... 9-1 9.1 Overview............................................................................................................................ 9-1 9.2 Normal Procedure.............................................................................................................. 9-1

9.2.1 Intra-BSC Handover Procedure .............................................................................. 9-1 9.2.2 Inter-BSC Handover Procedure .............................................................................. 9-4 9.2.3 Inter-MSC Handover Procedure.............................................................................. 9-6

9.3 Abnormal Cases ................................................................................................................ 9-7 9.3.1 Handover Failure Due to CIC Exception................................................................. 9-7 9.3.2 Handover Failure Due to MS Access Failure.......................................................... 9-7 9.3.3 Handover Procedure Initiation Failure .................................................................... 9-8

Chapter 10 Ciphering Mode Setting Procedure ....................................................................... 10-1 10.1 Overview........................................................................................................................ 10-1 10.2 Normal Procedure..........................................................................................................10-1 10.3 Internal Handling of BSC ............................................................................................... 10-2 10.4 Abnormal Cases ............................................................................................................ 10-3

10.4.1 Ciphering Rejected.............................................................................................. 10-3 10.4.2 MS Not Ciphered................................................................................................. 10-3

Chapter 11 Call Re-establishment Procedure .......................................................................... 11-1 11.1 Overview........................................................................................................................ 11-1 11.2 Normal Procedure..........................................................................................................11-1 11.3 Abnormal Cases ............................................................................................................ 11-3

11.3.1 CM Service Rejected .......................................................................................... 11-3




iv

11.3.2 Re-establishment Not Allowed or Re-establishment Failure .............................. 11-4 11.3.3 RR Connection Failure........................................................................................ 11-4

Chapter 12 Directed Retry Procedure ....................................................................................... 12-1 12.1 Overview........................................................................................................................ 12-1 12.2 Normal Procedure..........................................................................................................12-1

12.2.1 Directed Retry Intra-BSC Handover Procedure.................................................. 12-2 12.2.2 Directed Retry Inter-BSC Handover Procedure.................................................. 12-5 12.2.3 Directed Retry Inter-MSC Handover Procedure ................................................. 12-7

12.3 Abnormal Cases ............................................................................................................ 12-8 Chapter 13 Short Message Procedure ......................................................................................13-1

13.1 Overview........................................................................................................................ 13-1 13.2 Normal Procedure..........................................................................................................13-2

13.2.1 Short Message Procedure on SDCCH When MS Is Calling............................... 13-2 13.2.2 Short Message Procedure on SDCCH When MS Is Called ............................... 13-4 13.2.3 Short Message Procedure on SACCH When MS Is Calling............................... 13-6

13.3 Short Message Procedure on SACCH when MS Is Called........................................... 13-7 13.4 Internal Handling of BSC ............................................................................................... 13-7 13.5 Abnormal Cases ............................................................................................................ 13-8

Chapter 14 Cell Broadcast Message Procedure ...................................................................... 14-1 14.1 Overview........................................................................................................................ 14-1 14.2 CBC-BSC Interface Message Procedure ...................................................................... 14-1 14.3 Messages and Service Functions over the Interface between BSC and BTS .............. 14-5 14.4 Internal Handling of BSC ............................................................................................... 14-5 14.5 Abnormal Cases ............................................................................................................ 14-6

Appendix A Message Interpretation............................................................................................A-1 A.1 A-Interface Key Messages ................................................................................................A-1

A.1.1 Message Contents..................................................................................................A-2 A.1.2 Signaling element coding......................................................................................A-15 A.1.3 Message Type ......................................................................................................A-18

A.2 Abis-Interface Key Messages..........................................................................................A-62 A.2.1 Message Contents................................................................................................A-62 A.2.2 Signaling element coding......................................................................................A-69

Appendix B Difference between Phase1- Phase2- Phase2+.....................................................B-1 B.1 Difference between Messages over A-interface in Different Phases................................B-1 B.2 Difference Analysis............................................................................................................B-1

Appendix C Glossary....................................................................................................................C-1 Appendix D Abbreviation .............................................................................................................D-1 Appendix E Reference for GSM Protocols..................................................................................E-1



Signaling Analysis ManualM900/M1800 Base Station Subsystem Chapter 1 Signaling Fundamentals

1-1

Chapter 1 Signaling Fundamentals

1.1 Interface Overview

M900/M1800 BSS offers standard external interfaces including Um interface between

MS and BSS, A interface between BSS and MSC. The interface protocols and

interface procedures strictly follow the ETSI specifications.

The interfaces between each BTS and BSC and those between BSS and OMC are

internal interfaces, and are related to specific equipment from different manufacturers.

There are many regulations drafted by ETSI for the Abis interface between BTS and

BSC, but the regulations are still incomplete.

Figure 1-1 shows the GSM protocol stack. The following is an overall introduction to

each interface.

CM

MM

RR

LAPDm

Sign.

Layer1

L3

L2

L1

BTSM

MS

Um

SCCP

MTP

BTSM

RR BSSMAP

Abis

BTS

BSC

MSC

A

BSC

Sign.

Layer1

Sign.

Layer1

Sign.

Layer1

RR

LAPDLAPDm LAPD

CM

MM

BSSMAP

SCCP

MTP

MS: Mobile Station CM: Connection ManagementBSC: Base Station Controller MM: Mobility ManagementBTS: Base Transceiver Station MSC: Mobile services Switching Centre, Mobile Switching CentreMTP: Message Transfer Part (MTP) BTSM: Base Transceiver Station Site Management

RR: Radio Resource Management BSSMAP: Base Station Subsystem Management Application PartSCCP: Signaling Connection Control Part LAPD: Link Access Procedure on the D channelLAPDm: Link Access Procedure on the Dmchannel

Figure 1-1 GSM protocol stack

I. A interface

A interface is the standard interface between BSS and MSC. The information

transferred on this interface includes MS management, BTS management, mobility

management, connection management, etc.




1-2

II. Abis interface

Abis interface defines the standard of communication between BSC and BTS in BSS,

and is used in remote interconnection mode. This interface supports all MS-oriented

services, and supports the control of BTS radio equipment and the allocation of radio

frequencies.

III. Um interface

Um interface is defined as the communication interface between MS and BTS, and is

used for the interworking between MS and the fixed part of the GSM system. The

physical link is a radio link. The information transferred on this interface includes the

information of radio resource management, mobility management, connection

management, etc.

1.2 A-Interface

1.2.1 Overview

A interface is the interface between BSC and MSC. It is a standard interface in GSM

specifications, as it may involve the interworking between the equipment from

different manufactures. In the GSM system, SS7 is adopted on A interface.

Physically, A interface is the trunk circuit and trunk interface between BSC and MSC.

See Figure 1-2 for the A interface signaling protocol reference model.

A

Physical layer

MTP

SCCP

BSSAP

DTAP BSSMAP

Allocation function

MTP

SCCP

BSSAP

DTAP BSSMAP

Allocation function

BSS MSC

DTAP: Direct Transfer Application Part MTP: Message Transfer Part (MTP)SCCP: Signaling Connection Control Part BSSAP: Base Station Subsystem Application PartBSSMAP: Base Station Subsystem Management Application Part

Figure 1-2 A-interface signaling protocol reference model




1-3

1.2.2 Protocols on the A-Interface

I. Physical layer

The physical layer of the A-interface is 120-ohm symmetrical twisted pair or 75-ohm

coaxial cable whose rate is 2 Mbit/s. The physical layer of A-interface has the

following features:

z The 2 Mbit/s transfer rate complies with G.703.

z Frame structure, synchronization and timing comply with G.705.

z Fault management complies with G.732.

z CRC4 complies with G.704.

II. Message Transfer Part (MTP)

The main function of MTP is to ensure reliable signaling message transfer in the

signaling network. In case of system and signaling network faults, it takes measures

to avoid or reduce the loss of messages, repeated messages and out-of-sequence

packets.

MTP protocols are defined in ITU-T Q.701~710 Recommendations.

MTP comprises three functional levels: signaling data link function, signaling link

function and signaling network function.

1) Signaling data link function

Signaling data link (layer 1) is the channel used for signaling transmission. It

comprises two data channels of the same data rate but two opposite working

directions. The data rate is 64kbit/s. Generally, the signaling data link occupies

timeslot 16 of a trunk cable. The specific timeslot is to be determined by negotiation

between BSC and MSC. By data configuration, the timeslot can be used to establish

a semi-permanent connection.

The signaling data link is the information bearer of SS7. One of its important features

is that the signaling link is transparent, i.e. the data transferred on it cannot be

changed. Therefore, equipment such as echo canceller, digital attenuator, A/u rateconverter, cannot be connected to this link.

2) Signaling link function

Signaling link function (layer 2) regulates the functions and procedures to send the

signaling to the data link, and together with layer 1, it implements reliable signaling

message transfer between two directly-connected signaling points. Due to

long-distance transmission, a certain rate of bit errors may be caused on the data link

between two adjacent signaling points. However, no error is allowed in CCS7

signaling message codes. The purpose of layer 2 is to guarantee error-free

transmission of message codes in the case that there exist bit errors on layer 1.




1-4

Functions of layer 2 include: signaling unit delimitation, signaling unit alignment, error

detection, error correction, initial alignment, processor fault, level-2 flow control, and

signaling link error rate monitoring.

3) Signaling network function

By controlling the route and performance of the signaling network, signaling network

function (level 3) guarantees that signaling information can be reliably transferred to

the user part, whether the signaling network is in normal state or not.. Signaling

network functions include signaling message processing and signaling network

management.

a) Signaling message processing

Signaling message processing function sends signaling messages to the

corresponding signaling links or user parts. The user part in BSS only contains SCCP.

Signaling message processing functions comprise three parts: message routing

(MRT), message discrimination (MDC) and message distribution (MDT), as shown in

Figure 1-3.

Message allocation

Message to local office

Message to other SP

MTP user part

MTP L3 signaling message processing

MTPL2 signaling message processing

Messagerouting

Messagediscrimination

Figure 1-3 Signaling message processing procedure

z Message Routing

MRT (Message Routing) function is used at each signaling point to determine the

signaling link group and the signaling link to destination signaling point. The MRT part

implements the selection of message routes. In other words, by using the information

(DPC and SLS) contained in the route mark, it selects a signaling link for signaling

messages, so that the messages can be transferred to the DPC.

z Message Discrimination (MDC)




1-5

Message Discrimination (MDC) part is designed to receive the messages from Layer

2 to ascertain whether the destination of the messages is the local signaling point. If

the destination is the local signaling point, the MDC part will send the messages to

the Message Distribution (MDT) part. If the destination is not the local signaling point,the MDC part will send the messages to the Message Routing (MRT) part.

z Message Distribution (MDT)

Message Distribution (MDT) part is designed to allocate the messages from the MDC

part to the user part and the signaling network management and test & maintenance

part accordingly.

b) Signaling network management

Signaling network management is to re-construct the signaling network and to keep

and recover the normal transfer ability of the signaling unit when the signalingnetwork fails. Signaling network management includes three parts: signaling traffic

management, signaling link management and signaling route management.

z Signaling Traffic Management (STM)

Signaling Traffic Management (STM) is to transfer the signaling data from one

link/route to another or multiple available links/routes when the signaling network fails.

It is also used to temporarily reduce signaling traffic in case of congestion at the

signaling point.

z Signaling link management

Signaling link management (SLM) is to recover or enable the signaling link in the

signaling network or to disconnect the signaling link. It ensures the provision of

certain pre-determined link groups. The connection between the signaling data link

and the signaling terminal is normally established by the man-machine commands.

Operations in the signaling system can not automatically change the above

connection relationship.

z Signaling route management

Signaling route management (SRM) is used to ensure the reliable exchange of

signaling route availability information between signaling points so as to block or

unblock signaling routes when necessary. It mainly comprises such procedures as

transfer prohibited, transfer allowed, controlled transfer and restricted transfer,

signaling route group test, and signaling route group congestion test.

III. Signaling Connection & Control Part (SCCP)

The purpose of SCCP is to provide complete network layer functions with the help of

MTP. Network layer provides connectionless services and connection-oriented

services.




1-6

The network layer services provided by SCCP can be classified into connectionless

services and connection-oriented services. The connectionless service means that

MS does not establish a signaling connection in advance, and uses the routing

functions of SCCP and MTP to directly transfer data information in the signalingnetwork. It is applicable to the transfer of a small quantity of data. The

connection-oriented service means that a signaling connection is established in

advance, and data are directly transferred on the signaling link, instead of using the

route selection function of SCCP. It is applicable to the transfer of large quantities of

data, and effectively shortens the transmission delay of batch data.

SCCP has routing and network management functions. The routing function of SCCP

is to perform addressing as per the address information such as DPC, SSN, GT, etc.

DPC refers to the destination signaling point code adopted by MTP, and SSN refers to

the subsystem No., which is used to identify the different users (such as ISUP, MAP,TCAP and BSSAP) of SCCP in the same node, so as to compensate the insufficiency

of users of MTP and to enlarge the addressing scope. GT addressing mode is not

introduced as BSS does not adopt this addressing mode.

The network management function of SCCP is to implement management of

signaling point state and subsystem state, switchover of active/standby subsystem,

broadcasting of status messages and testing of subsystem state. SCMG (SCCP

management) is to maintain the network functions by reselecting a route or adjusting

the traffic volume when network fault or congestion occurs. MTP protocols are

defined in ITUT Q.711~716 Recommendations

IV. BSSAP

1) Protocol overview

The BSSAP protocol, which serves as A-interface specification, describes two kinds

of messages, BSSMAP and DTAP message. BSSMAP messages are used for traffic

flow control, and are to be processed by the internal functional module of the

corresponding A interface. For DTAP messages, A interface is merely equivalent to a

transport channel, On BSS side, DTAP messages are directly transferred to radio

channels. On MSC subsystem side, DTAP messages are transferred to thecorresponding functional processing unit.

BSSAP protocols are defined in ETSI GSM 08.08 and ETSI GSM 04.08

specifications.

2) Typical message contents

a) DTAP messages

The DTAP messages can be divided into Mobile Management (MM) messages and

Call Control (CC) messages.




1-7

The MM messages consist of messages related to authentication, CM service

request, identification request, IMSI detach, location update, MM state, TMSI

re-allocation, etc.

The call control messages consist of alerting, call proceeding, connection, setup,

modification, release, disconnection, notification, state query, DTMF startup

messages, etc.

b) BSSMAP messages

The BSSMAP messages can be divided into connectionless and connection-oriented

messages.

z The connectionless messages consist of Block/Unblock, Handover, Resource,

Reset, Paging messages, etc.

The Block/Unblock messages include Block & Block ACK messages and Unblock &

Unblock ACK messages. The Circuit Group Block/Unblock messages include Circuit

Group Block message, Circuit Group Block ACK message, Circuit Group Unblock and

Circuit Group Unblock messages.

Handover messages include Handover Candidate Enquire and Handover Candidate

Enquire Response.

The resources messages include Resources Request and Resource Indication

messages.

The Reset messages include Reset and Reset ACK messages.

z The connection-oriented messages include Assignment, Handover, Clear and

Cipher messages.

The Assignment messages include Assignment Request, Assignment Complete and

Assignment Error messages.

The Handover messages include Handover Request, Handover Request ACK,

Handover Command, Handover Complete and Handover Error messages.

The Clear messages include Clear Request and Clear Complete messages.

The Cipher messages include Cipher Mode Command and Cipher Mode Complete

messages.

c) BSSAP protocol functionality

The BSSAP protocol can deliver its own functions in connection-oriented mode and

connectionless mode of SCCP. When MS needs to exchange service-related

messages over radio resources with the network side while there is no MS-related

SCCP connection between MSC and BSS, a new connection will be established. A

new connection shall also be set up for external handover. There are two kinds of

connection setup:




1-8

z While MS sends the Access Request message on the RACH, BSS allocates a

dedicated radio resource (DCCH or TCH) to MS. After the L2 connection is set

up on the SDCCH (or FACCH) where resources are allocated, BSS starts the

connection setup.z When MSC decides to execute an external handover (the target BSS might be

the original BSS), it must reserve a new DCCH or TCH from the target BSS. In

this scenario, MSC starts the connection setup.

The BSSAP protocol implements the functional flow as shown in Table 1-1 using the

connection and connectionless messages.

Table 1-1 Major functions of BSSAP

Serialnumber

Function Description

1 Assign

“Assign” is to ensure the dedicated radio resources are allocatedor re-allocated properly to the MS. The initial MS random accessand “immediate assignment” to a DCCH is processedautomatically by BSS but not controlled by MSC.

2 Block/UnblockDuring circuit assignment, MSC selects an available terrestrialchannel. If this channel is no longer available then BSS notifies itto MSC. The Block/Unblock procedure can carry out this function.

3 ResourceIndication

Resource indication serves to notify MSC:

Amount of the radio resource available for TCH in BSS,

Amount of all available radio resource (i.e. able to provide serviceor have been specified)

It is not easy to get this information from the MSC-controlledservices. These must be considered when MSC decides anexternal handover.

4 Reset

“Reset” is to initialize the BSS or MSC. For instance, if BSS goesfaulty or loses all the reference messages about processing, BSSsends a Reset message to MSC, which releases the affected calls,deletes the affected reference messages and sets all the circuitsrelated to the BSS to idle.

If MSC or BSS is only locally faulty, the affected parts can be

cleared using the Clear procedure.




1-9

Serialnumber


5Handover Request

BSS may send a “handover request” to MSC requesting to performhandover of the MS, to which dedicated resources have beenallocated, for the reasons as listed below:

a) BSS detects a radio cause for handover.

b) MSC starts the Handover Candidate Enquirer procedure. TheMS is waiting for the handover.

Due to congestion, the serving cell needs to be changed during thecall setup such as directed retry.

The Handover Request messages should be re-sent once in awhile till one of the following situations occurs:

Receive the "Handover Command" message from MSC

Reset message is received

All communications with MS will be interrupted and the processingis aborted

Processing is over, such as call clearing.

6Handover Resource Allocation

Handover Resources Allocation enables MSC to request for resources from BSS based on the handover request. The targetBSS will reserve resources and wait for an MS to access thischannel.

7 Handover Procedure

This is the procedure in which MSC instructs MS to access theradio resources of another cell. When handover is carried out, theoriginal dedicated radio resources and terrestrial resources aremaintained all the time until MSC sends a Clear Commandmessage or Reset occurs.

8

Release of RadioResources andTerrestrialResources

When processing is done, MSC sends a “Clear Command” to BSSto release radio resources. On receiving the command, BSS startsthe Clear procedure at the radio interface, then sets the configuredterrestrial circuit to idle and returns a Clearing Complete messageto MSC, which in turn releases the terrestrial resources of the localend.

If resources need to be released by BSS, BSS will send a “Clear Request” to notify MSC to start the release procedure to release

the terrestrial and radio resources concerning MSC and BSS.

9 Paging

The paging to MS is transported with the SCCP connectionlessservice via BSSMAP. If BSS receives the Paging Responsemessage at the radio channel interface, it will establish an SCCPconnection to MSC. The paging response message, which isloaded in the BSSMAP Full L3 Message, is transported on thesignaling connection to MSC.

10 Flow Control

Flow control can prevent the entities from receiving too muchtraffic. Flow control on the A-interface is implemented bycontrolling the traffic at the traffic source. Two levels of flow controlare available. Flow control can be implemented based on

subscriber classes.




1-10

Serialnumber


11 ClassmarkUpdate

Classmark Update serves to notify the class messages receivedfrom MS to the receiving entities. Generally, BSS notifies MSCafter receiving the class messages from MS. It is also likely thatwhen handover is complete, MSC sends the corresponding MSClassmark messages to the new BSS via the A-interface.

12Cipher ModeControl

The Cipher Mode Control procedure allows MSC to transport thecipher mode control messages to BSS and start the subscriber equipment and signaling cipher equipment with a correct Kc.

13QueuingIndication

This procedure is designed to notify MSC that BSS wants to delaythe allocation of necessary radio resources. This procedure is validonly when the queuing function is introduced for traffic channelassignment and traffic channel handover in the BSS.

14 Load Indication

Load indication serves to notify the traffic state of a cell to all theadjacent BSSs so that an overall control over the handover services in an MSC can be exercised. In a certain valid period, thetraffic state of the adjacent cells will be taken into account by theadjacent BSS during handover.

1.3 Abis interface

1.3.1 Overview

The Abis interface is the interface between Base Station Controller (BSC) and Base

Transceiver Station (BTS), and complies with the requirements of 08.5X series of the

GSM specifications. It is merely an internal interface of BSS. The interworking

between the BSC and BTS equipment of different manufactures has not been

realized.

The terrestrial traffic channels on the Abis interface and the radio traffic channels on

the Um interface are in one-to-one correspondence with one another.

I. Protocol Model

The protocol model of the Abis interface is shown in Figure 1-4.




1-11

LAPDm

Sign

Layer1

LAPD

Layer1

LAPD

Layer1

SCCP

MTP

BTSM

RR BSSAP

Abis

BTS BSC

RR BTSM

BTSM: Base Transceiver Station Management LAPD: Link Access Procedure on the D ChannelLAPDm: Link Access Procedure on the Dm ChannelSCCP: Signaling Connection Control Part MTP: Message Transfer PartBSSAP: Base Station Subsystem Application Part RR: Radio Resource

Figure 1-4 Protocol model of Abis interface

z Layer 1 of the Abis interface is a physical link which receives data from and

transmits data to the transport layer based on the bottom layer driver of the

hardware.

z The layer 2 protocol of the Abis interface is based on the LAPD. LAPD

addresses TRX (or BCF) through TEI, and uses different logical links for

message transfer. RSL is to transfer traffic management messages. OML is to

transfer network management messages. L2ML is to transfer L2 management

messages.z RR (Radio Resource Management) messages are mapped onto the BSSAP

(BSS Application Part) in BSC. In BTS, most of RR messages are handled as

transparent messages. However, some of them have to be interpreted and

executed by BTS (for example, cipher, random access, paging and assignment),

these messages are processed by the BTSM (BTS Management) entities in BSC

and BTS.

z BSC and BTS do not interpret CM (Connection Management) and MM (Mobility

Management) messages. These messages are transferred over the A-interface

by DTAP (Direct Transfer Application Part). At the Abis interface, DTAP

messages are transferred as transparent messages.

II. Structure of Abis interface

The Abis interface can support three different internal BTS configurations (as

illustrated in Figure 1-5.

z Single TRX.

z Multiple TRXs are connected with the BSC via a common physical connection.

z Multiple TRXs are connected with the BSC via different physical connections.




1-12

Abis

BTS3

BTS2

BTS1

A

Abis

MSCBSC

TRX

BCF

TRX

BCF

Abis

BSS

TRX

TRX

TRX

TRX

TRX

TRX

BCF

Figure 1-5 Structure of Abis interface

As shown in Figure 1-5,

z TRX (Transceiver) is the functional entity that supports 8 physical channels that

belong to the same TDMA frame, which is defined in the PLMN.

z The BCF (Base Control Function) is the functional entity that performs common

control functions including BTS initialization, software loading, channel

configuration, operation and maintenance.

There are two types of channels at the Abis interface, which are:

z Traffic channels with the rates of 8kbit/s, 16kbit/s and 64kbit/s respectively,

carrying speech or data from radio channels.

z

Signaling channels with rates of 16kbit/s, 32kbit/s or 64kbit/s respectively,carrying signaling between BSC and MS, and between BSC and BTS.

Different Terminal Equipment Identifiers (TEI) are assigned to get unique addresses

of TRXs. Three separate logical links are defined with each TEI (as shown in

Figure 1-6).

z RSL: Radio Signaling Link used to support traffic management procedures, one

for each TRX.

z OML: Operation & Maintenance Link used to support network management

procedures, one for each SITE.

z

L2ML, L2 management link, for transferring the management messages at L2.




1-13

TEI1L2ML SAPI=63

RSL SAPI=0

OML SAPI=62

LAYER 2

TEI

MANAGE-

MENT

TRX

TRX

TRX

BCF

L2ML SAPI=63

RSL SAPI=0

OML SAPI=62

L2ML SAPI=63

RSL SAPI=0

OML SAPI=62

BCF

BCF

BCF

BCF

L2ML SAPI=63

OML SAPI=62

BSC BTS

TEI2

TEI3

TEI4

Figure 1-6 Abis interface layer 2 logical links

1.3.2 Protocols on the Abis Interface

I. Physical layer

Abis interface physical layer adopts the PCM link with the working rate at 2048 kbit/s

to provide 32 channels at 64kbit/s. The electro-technicial parameter at the physical

layer conforms to the CCITT G.703 recommendations.

BSS is the connection point of the radio channel and terrestrial channel. Both kinds of

channels have different transfer patterns and coding rates. In the radio channel of

BSS, the transfer rate is 16kbit/s while it is 64kbit/s in the terrestrial channel.Therefore transcoding and rate adaptation is needed. To save cost more efficiently,

different multiplexing ratio modes are adopted on Abis interface, e.g. 10:1/12:1/15:1

multiplexing mode.

II. Data link layer

1) Overview

The data link layer of Abis uses LAPD protocol. It utilizes the service on the physical

layer, and provides connection-oriented or connectionless services for layer 3. The

data link Service Access Point (SAP) is the point that provides services for layer 3.




1-14

SAP is identified by Service Access Point Identifier (SAPI). A data link connection

endpoint is identified by a data link connection endpoint identifier as seen from layer 3

and by a data link connection identifier (DLCI) as seen from the data link layer.

For information exchange between two or more layer 3 entities, an association must

be established between the layer 3 entities in the data link layer using a data link

layer protocol.

The communication between data link layer entities is governed by a peer-to-peer

protocol specific to the layer. Messages at the data link layer are transferred between

entities at layer 2 through physical layer. Inter-layer service request is implemented

with service primitive.

2) Function

The purpose of LAPD is to realize reliable end-to-end information transfer betweenlayer 3 entities through the user-network interface by using the D-channel. To be

specific, LAPD supports:

z Multiple terminal equipment between subscriber and interface,

z Multiple L3 entities.

Functions of LAPD includes:

z Establishes one or several data links on the D channel.

z Delimits, locates and transmits transparently frames so that a string of bits

transmitted on the D channel in the form of frames can be identified.

z Implements sequence control to keep the order of the frames that pass the datalink connections.

z Checks the transmission errors, format errors and operation errors in the data

link connections.

z Makes recovery based on the detected transmission errors, format errors and

operation errors.

z Notifies the management layer entities of the unrecoverable errors.

z Flow control.

Data link layer provides the means for information transfer between multiple

combinations of data link connection points. The information may be transferred

through point-to-point data link connections or via broadcast data link connections.

III. Traffic management of Layer 3

The traffic management part of the Abis interface layer 3 is mainly described in GSM

08.58 specifications. The procedures defined in this specifications has two major

functions:

z Realizing the interworking of the MS and BSS/NSS on the Um interface.

z Implementing part of the radio resource management functions under the control

of BSC.




1-15

The traffic management message is divided into the transparent and non-transparent

messages,

z The transparent message refers to the messages forwarded without

interpretation or being processed by the BTS. z The non-transparent message refers to the messages processed and structured

by the BTS.

The traffic management messages can also be divided into four groups in terms of

functions, which are:

z Radio link layer management message, used for the management of the data

link layer on the radio channel.

z Dedicated channel management message used for the management of

dedicated channels (SDCCH and TCH).

z Common control channel management message used for the management of common control channels.

z TRX management message used for TRX management.

z

Transparency and group of the message is determined by the message discriminator

at the header of the message.

1) Radio link layer management procedures

Radio link layer management procedures include:

z Link establishment indication procedure: BTS uses this procedure to indicate to

BSC the success of setting up multi-frame link originated by the subscriber. BSC

establishes a link from MSC to SCCP through the indication.

z Link establishment request procedure: This procedure is used by BSC to request

the establishment of a link layer connection in multi-frame mode on the radio

channel.

z Link release indication procedure: This procedure is used by BTS to indicate to

BSC that a link layer connection on the radio channel has been released at the

initiative of an MS.

z Link release request procedure: This procedure is used by BSC to request the

release of a link layer connection on the radio channel. z Transmission of a transparent L3-message on the Um interface in acknowledged

mode: This procedure is used by BSC to request the sending of a transparent L3

message to MS on the Um interface in acknowledged mode.

z Reception of a transparent L3-message on the Um interface in acknowledged

mode: This procedure is used by BTS to indicate the reception of a transparent

L3 message on the Um interface in acknowledged mode.

z Transmission of a transparent L3-message on the Um interface in

unacknowledged mode: This procedure is used by BSC to request the sending

of a transparent L3 message to MS on the Um interface in unacknowledged

mode.




1-16

z Reception of a transparent L3-message on the Um interface in unacknowledged

mode: This procedure is used by BTS to indicate the reception of a transparent

L3 message in unacknowledged mode.

z

Link error indication procedure: Through this procedure BTS indicates BSCincase of any abnormality in the radio link layer.

2) Dedicated channel management procedures

The dedicated channel management principles includes:

z Channel activation procedure: This procedure is used to activate a channel at

BTS for an MS which later will be commanded to this channel by an Immediate

Assignment, an Assignment Command, an Additional Assignment or a Handover

Command message.

z Channel mode modification procedure: This procedure is used by BSC to

request a change of the channel mode of an active channel.

z Handover detection procedure: This procedure is used between the target BTS

and BSC to detect the accessing of the MS being handed over.

z Start of encryption procedure: This procedure is used to start encryption

according to the procedure defined in Technical Specification GSM 04.08.

z Measurement report procedure: It includes the necessary basic measurement

report procedure and measurement report preprocessing procedure. BTS reports

all parameters related to handover decision to the BSC through this procedure.

z Deactivate SACCH procedure: This procedure is used by BSC to deactivate the

SACCH at BTS according to the Channel Release procedure defined in

Technical Specification GSM 04.08.

z Radio channel release procedure: This procedure is used by BSC to release a

radio channel that is no longer needed.

z MS power control procedure: This procedure is used by BSS to set the MS

power level or the parameters required by TRX. MS power control decision must

be implemented in BSC, and as an optional procedure in BTS.

z BTS Transmission power control procedure: This procedure used between BSC

and BTS to set the TRX transmission power level or the parameters required by

TRX. The BTS transmission power control decision should be implemented in

BSC, or in BTS.

z Connection failure procedure: This procedure is used by BTS to indicate to BSC

that an active connection has been broken.

z Physical context request procedure: This is an optional procedure which allows

the BSC to obtain information on the "physical context" of a radio channel just

prior to a channel change.

z SACCH information modification procedure: BSC uses this procedure to instruct

BTS to change the information (system information) filled in a specific SACCH

channel.

3) Common channel management procedures

Common channel management regulations include:




1-17

z Channel request by MS procedure: The procedure is initiated by TRX upon

detection of a random access from an MS (Channel Request message from

MS).

z

Paging principle procedure: It is used to page an MS on the specified pagingsub-channel. The paging of an MS is initiated by BSC sending a Paging

Command message to BTS. BSC determines the paging group to be used

according to the IMSI of the called MS. The value of this paging group together

with the identity of the mobile station is sent to BTS.

z Immediate assignment procedure: When a mobile station accesses BTS, BSC

uses this procedure to assign a dedicated channel for the mobile station

immediately.

z Delete indication procedure: This procedure is used by BTS to indicate that due

to overload on the AGCH, an Immediate Assign Command has been deleted.

z CCCH load indication procedure: This procedure is used by BTS to inform BSC

the load on a designate CCCH. Indication period is also set by OM.

z Broadcast information modification procedure: This procedure is used by BSC to

indicate to BTS the new information to be broadcast on BCCH.

z Short message cell broadcast procedure: Short Message Service Cell Broadcast

messages are sent to BTS as SMS Broadcast Request messages.

4) TRX management procedures

This type of procedure is used for TRX management. There are:

z SACCH filling information modify procedure: This procedure is used by BSC to

indicate to BTS the new information to be used as filling information on SACCHs.

z Radio resources indication procedure: This procedure is used to inform BSC on

the interference levels on idle channels of a TRX.

z Flow control procedure: This procedure is defined to give some degree of flow

control. It can be used for TRX processor overload, downlink CCCH overload

and AGCH overload.

z Error reporting procedure: This procedure is used by BTS to report detected

downlink message errors, which cannot be reported by any other procedure.

IV. Operation and maintenance part of Layer 3

1) Operation and maintenance information model

z Managed objects

There are four types of management objects: site, cell, carrier and channel. The basic

structure is illustrated in Figure 1-7.




1-18

SITE

CELL 0 CELL 1CELL n

TRX0 TRX1 TRXm

TRX

CH0 CH1 CH7

Figure 1-7 Basic structure of management object

z Object addressing

Addressing of network management messages is realized by means of managed

object types and cases. For each object case in BTS there is a complete L2

connection description. The setup of the first connection uses one (semi-) permanent

default TEI. Subsequent connections use the TEIs provided when setting up TEI

procedures. Object cases can also use layer 3 addresses. The mixed use of layer 2

and layer 3 addressing enables one BTS site to have one or multiple physical links.

z Managed object state

Management status include management status, operation status and availabilitystatus. See Table 1-2, Table 1-3 and Table 1-4. The management state of managed

objects is only controlled by BSC, and available state is the specific explanation of

operative state.

Table 1-2 Management status

State Description

LockedBSC has disconnected all calls through this managed object, and no new callscan be connected to this object.

Shut down New services can not be connected to this managed object, but those existingcalls will be maintained.

Unlocked New calls can be connected to this managed object.

Table 1-3 Operation status

State Description

DisabledResources are completely unavailable, and can no longer provide services tothe users.




1-19

State Description

Enabled All or part of resources are available and can be used.

Table 1-4 Availability status

State Description

ln test The resource is being tested. Its operational state is disabled.

FailedThe source/object is not working due to some internal error. Itsoperational state is disabled.

Power off The resource needs power supply. Its operational state is disabled.

Off lineThe resource needs manual or automatic operations. Its operational

state is disabled.

DependencyServices provided by this resource are degraded in a certain sense,such as rate or operational capacity. Its operational state is disabled.

DegradedServices provided by this resource are degraded in a certain sense,such as rate or operational capacity. Its operational state is enabled.

Not InstalledHardware or software of the managed objects is not installed. Itsoperational state is disabled.

2) Basic procedures

All procedures are based on formatted O&M messages. Most formatted O&M

messages initiated by BSC or BTS require the peer layer 3 endpoint to give response

or acknowledgment in the form of formatted O&M messages. This pair of formatted

O&M messages or a single formatted O&M message that need not be responded to

is called a basic procedure. All formatted O&M messages are sent on layer 2 in the

form of I frames. A group of procedures, called as structured procedures, are based

on the combination of some basic procedures.

For a specific object, if a certain basic procedure is not completed, the system will not

start its subsequent basic procedures. When there is no response to the formatted

operation and maintenance message from the peer layer 3 before L3 timeout, the

basic procedure is regarded as “not completed”. When the previous basic procedure

has not received any response (ACK or NACK) before layer 3 timeout, then no

subsequent basic procedure is sent to this object case. The default timeout for layer 3

is 10s. If part of an original message is not understood or supported, the whole

message is discarded. A ACK message returned by the object indicates affirm

response, it is used to notify the message sender that the command has been

executed or will be executed. A NACK message returned by the object indicates

disaffirm response, it is used to notify the message sender that the command

executed unsuccessfully and the corresponding failure cause.




1-20

There are mainly the following types of basic procedures:

z Software loading management procedure

z Abis interface management procedure

z Transmission management procedurez Air interface management procedure

z Test management procedure

z State management and event reporting procedure

z Equipment state management procedure

z Other procedure

1.4 Um Interface

Um interface (air interface or radio interface) is defined as the communication

interface between MS and BSS. It is for the communication between MS and the

fixed part of GSM. Its physical link is the radio link. The information transmitted via

this interface include radio resource management, mobility management and

connection management.

1.4.1 Overview

In a GSM network, MS is connected through radio channels to the fixed network so

that communication services can be routed to the specific destination. To realize the

inter-working between MS and BSS, it is necessary to standardize the transmission of the signals on the radio channel. The norm concerning the signal transmission on the

radio channel is the radio interface, or Um interface.

The Um interface is specified by the following features:

z Channel structure and access capability

z MS-BSS protocols

z Maintenance and operation characteristics

z Performance characteristics

z Service characteristics.

The Um interface can be divided into 3 layers, as shown in Figure 1-8.

L3

L2

L1

Figure 1-8 Layered structure of Um interface




1-21

The first layer is the physical layer at the bottom. It defines the radio access

capabilities of GSM, and provides basic radio channels for information transfer on

higher layer.

The layer 2 is the data link layer using the LAPDm protocol. It defines various data

transmission structures, and controls data transmission.

The layer 3 is the highest layer. It includes various messages and programs, and

controls services. It includes 3 sub-layers, which are Radio Resources management

(RR), Mobility Management (MM), and Connection Management (CM).

1.4.2 Layer 1 - Physical Layer

The physical layer (L1) is the lowest part of the Um interface. It provides the physical

links needed for transferring bit streams, and provides various logical channels for the

higher layers, including traffic channels and signaling channels. Each logical channel

has its own logical access point.

Physical layer interface and services:

The interfaces between the physical layer (L1) and data link layer (L2), the physical

layer (L1) and radio resources management sublayer (RR) of L3, the physical layer

(L1) and other functional unit, are shown in Figure 1-9.

Radio resourcemanagement L3

Data link

MPH Primitive PH Primitive

Physical layer

TCH

Other functional unit

Figure 1-9 Physical layer interface

The physical layer provides the following services:

z Access capability: the physical layer provides a series of limited logical channels

for transmission service. The logical channel is multiplexed on the physical

channel. There exist 8 physical channels on each TRX. Through data

configuration, logical channels are mapped to physical channels

z Error code detection: Physical layer provides error protection transmission,

including error detection and correction.




1-22

z Ciphering: Use the selected encrypt algorithm to transmit bit sequence

encrypted.

1.4.3 Layer 2 - Data Link Layer

The purpose of the data link layer is to establish reliable dedicated data links between

MS and BTS. The link layer protocol used by the GSM system at the radio interface is

the LAPDm protocol which has evolved from the LAPD protocol. It receives the

service from the physical layer and provides service to L3. The data link Service

Access Point (SAP) is the node that provides services for layer 3. SAP is identified

through SAPI. Each SAP is associated with one or multiple Data Link Connection End

Points (DLCEP). Currently, two SAPI values are defined in the LAPDm protocol, 0

(main signaling) and 3 (short messages).

LAPDm

1) Function

LAPDm transfers information between layer 3 entities through the radio interface on

the Dm channel. LAPDm supports multiple layer 3 entities and physical layer entities,

and signaling of BCCH, PCH, AGCH and DCCH.

Note:

The Dm channel is a generic term for all the signaling channels at the Um interface in the GSM system.

For instance, the Dm channel can either be PCH or BCCH.

LAPDm includes functions for:

z The provision of one or more data link connections on a Dm channel.

Discrimination between the data link connections is by means of a data link

connection identifier (DLCI).

z Allows for frame type identification.

z Allows L3 message units to be transmitted transparently between L3s.

z Exercises sequence control to maintain the order of frames that pass DLC.

z Check on the format and operation errors on the data links.

z Flow control.

z Contention resolution when establishing a data link after an access request has

been made on the RACH.

2) Operation types

Two types of operation of the data link layer are defined for layer 3 information

transfer: unacknowledged operation and acknowledged (multiple frame) operation.

They may co-exist on a Dm channel.




1-23

z Unacknowledged mode:

In unacknowledged mode, layer 3 information is transmitted in Unnumbered

Information (UI) frames. At the data link layer, the UI frames are not acknowledged.

Flow control mechanisms and error recovery mechanisms are not defined. Unacknowledged operation is applicable to different types of control channels except

for RACH.

z Acknowledged mode:

In acknowledged mode, layer 3 information is transmitted in Unnumbered Information

(UI) frames. The data link layer acknowledges the transmitted I frame. Error recovery

procedures based on retransmission of unacknowledged frames are specified. In

case of errors, which cannot be corrected by the data link layer, a report is issued to

the layer 3 entity. Flow control procedures are also defined. Acknowledged operation

is applicable to DCCH.

3) Information transfer mode:

On different channels, information transfer modes are different.

z Information transfer on the BCCH: The BCCH exists only in the network to MS

direction and is used for broadcasting radio sub-system information to MSs. Only

the acknowledged mode can be adopted on the BCCH.

z Information transfer on the PCH + AGCH: These channels exist only in the

network to MS direction. On the PCH + AGCH only unacknowledged operation is

possible.

z Information transfer on the DCCHs: On the DCCHs, either acknowledged or

unacknowledged mode may be adopted. The mode required at any time is

determined by layer 3.

4) Release of data links:

Multiple frame operation may be released in the following ways:

z Normal release by exchange of commands/responses.

z Local end release, i.e. without exchange of commands/responses, initiated and

controlled by layer 3.

1.4.4 L3

I. Introduction

The signaling layer 3 of the Um interface provides the functions to establish, maintain

and terminate circuit-switched connections across a GSM PLMN and other networks

to which the GSM PLMN is connected. It provides the necessary supporting functions

related to supplementary services control and short messages service control.

Furthermore it includes the functions necessary for mobility management and radio

resource management.




1-24

The layer 3 entity consists of many functional program blocks. These program blocks

transfer message units carrying various kinds of information among all layer 3 entities

and between layer 3 and neighboring layers. The objectives of the layer 3 are to

provide the means for:z The establishment, operation and release of a dedicated radio channel

connection (RR).

z For location updating, authentication and TMSI reallocation (MM).

z For establishment, maintaining and termination of circuit-switched calls (CC).

z Supplementary services support (SS).

z Short messages service support (SMS).

Layer 3 consists of 3 sub-layers including Connection Management (CM), Mobility

Management (MM) and Radio Resource management (RR). The CM sub-layer

contains multiple call control (CC) units, which are to implement concurrent callhandling. It also contains SS units and SMS units, which are respectively used to

support supplementary services and short message services.

The functions of the signaling layer 3 are performed by means of the signaling layer 3

protocols between two systems which represent the Mobile Station side and the

Network side of the radio interface as viewed by the Mobile Station. GSM 04.07 does

not consider the distribution of signaling functions among the different network

equipment. The functions of layer 3 and its supporting lower layers, therefore, provide

the Mobile Network Signaling (MNS) Service to the upper layers.

Interaction between layer 3 and higher layers and between services interfaces of

layer 2 as well as that between neighboring sub-layers in layer 3 can be described in

primitives and parameters. Exchange of information between two peers of the

signaling layer 3 is performed by means of the three sublayer protocols.

II. L3 Structure

As have already introduced, the 3 sub-layers of layer 3 are further discussed here:

Among them, The CM sub-layer (the highest sub-layer) is composed of three

functional entities: Call Control (CC), Short Message Service support (SMS) and

Supplementary Service support (SS). In total, there are five functional entities

consisted in the layer 3 radio interface. Below is the brief introduction to these

entities:

z Radio Resources (RR) management handles the establishment, maintenance,

and release of physical channels and logical channels, as well as cross-cell

transfer on the request of CM sub-layer.

z Mobility Management (MM) deals with the all necessary functions of mobile

features to support mobile subscribers. It notifies the network when the mobile

station is activated and deactivated, or the location area is changed. It is also

responsible for the security of activated radio channels.




1-25

z CC deals with all necessary functions to establish or release the circuit-switched

connections.

z SS deals with all necessary functions to support GSM supplementary services.

z

SMS performs all necessary functions to support point-to-point short messageservices.

In addition, other functions are contained in layer 3 which are related to the transport

of messages, e.g. multiplexing and splitting. Those functions are defined in the Radio

Resource Management and Mobility Management. They have the task to route the

messages according to the protocol discriminator (PD) and transaction identifier (TI)

which are part of the message header.

The MM routing function route the messages of the CM entities and the messages of

the MM entity of its own sublayer towards the service access point of RR, and

multiplex them in case of parallel transactions. The routing function of RadioResource Management shall distribute the messages to be sent according to their

protocol discriminator (PD) and the actual channel configuration.

The messages provided at the different service access points of layer 2 are split by

the RR routing function according to the protocol discriminator (PD). If PD equals to

RR, this message will be transferred to RR at the local sub-layer. Other messages

are provided to MM via the access point RR-SAP. The routing function of MM passes

the messages according to the protocol discriminator (PD) and the transaction

identifier (TI) towards the MM entity or towards the CM entities via the various

MM-SAP's.

Figure 1-10 illustrates the protocol model of L3 signaling.

The RR sub-layer at the bottom receives services provided by layer 2 through various

service access points (i.e., various types of channels) of layer 2, and provides

services via RR-SAP to the MM sub-layer. The MM sub-layer provides services to the

three entities (CC, SS and SMS) on the CM sub-layer through different service

access points MMCC-SAP, MMSS-SAP and MMSMS-SAP respectively, provides

register services to the higher layer through MMREG-SAP service access points. The

3 independent entities on the CM sub-layer provide services to higher layers through

MNCC-SAP, MNSS-SAP and MNSMS-SAP respectively.




1-26

CC

MNCC-SAP

SS

MNSS-SAP

SMS

MNSMS-SAPMobile Service

MMREG -SAP

MMCC-SAP

MMSS-SAP

MMSMS-

SAP

MM CC SS SMSMM

RR-SAP

..RR

RR

PD

RR

SAPI 0 SAPI 3

R A C H

S D C C H

S A C C H

F A C C H

B C C H

S D C C H

S A C C H

A G C H + P C H

L a y e r 3 S i g n a l i n g

Figure 1-10 Um interface L3 protocol model

III. Service characteristics.

1) Services provided by layer 3 on the MS side

z Registration services, i.e., IMSI attach and detach operations.

z Call Control services, including MS originating normal call establishment, MS

originating emergency call establishment, call hold, call termination, and call

related Supplementary Services Support.

z Call independent Supplementary Services Support.

z Short Message Services Support.




1-27

2) Services provided by layer 3

z on the network side Call Control Services, including call establishment, call

maintaining, call termination and call related supplementary service support.

z

Call independent Supplementary Services Support.

z Short Message Services Support.

3) Inter-layer services between the mobile station and network side

z Services provided by Radio Resource Management entity (Refer to Figure 1-11).

These services are provided to MM via RR-SAP. They are used for establishing

control channel connections, establishing traffic channel connections, ciphering

mode indication, releasing control channel connections, and control-data

transfer.

z Services provided by mobility management entities (MM) (Refer to Figure 1-12).

These services support call control, supplementary services and short messages

services of connection management entities.

RR

SAP

MS Network Side

MM

RR

RR - Primitive

corresponding layer protocol

Figure 1-11 Communication at RR




1-28

CC SMSS

MS

MM

CC SMSS

Network Side

MM

Corresponding layer protocol

Figure 1-12 Communication at MM



Signaling Analysis ManualM900/M1800 Base Station Subsystem Chapter 2 Signaling Trace Guide

2-1

Chapter 2 Signaling Trace Guide

2.1 Overview

Figure 2-1 shows the GSM protocol stack.

CM

MM

RR

LAPDm

Sign.

Layer1

L3

L2

L1

BTSM

MS

Um

SCCP

MTP

BTSM

RR BSSMAP

Abis

BTS

BSC

MSC

A

BSC

Sign.

Layer1

Sign.

Layer1

Sign.

Layer1

RR

LAPDLAPDm LAPD

CM

MM

BSSMAP

SCCP

MTP

MS: Mobile station BTS: Base Transceiver Station BSC: Base Station Controler MSC: Mobile Switching Center CM: Connection Management MM: Mobility ManagementRR: Radio Resource

management

MTP: Message Transfer Part SCCP: Signaling Connection Control Part

LAPD: Link Access Protocol on the D channel LAPDm: Link Access Protocol on the Dm channelBSSMAP: Base Station System Management Application Part BTSM: BTS Management

Figure 2-1 GSM protocol stack

The interfaces of BSS include the A interface between BSC and MSC, the Um interface

between BTS and MS, and the Abis interface between BSC and BTS.

The Base Station System (BSS) of Huawei provides powerful interface trace functions.

During equipment interconnection (like the interconnection between the BSC of

Huawei and MSC of another company) and equipment maintenance (such as frequent

call drop, low handover success rate, MS access-to-network failure, and poor speech),

these functions can be used to analyze the signaling procedure online, and locate the

faults promptly.

BSS interface trace functions include Um interface trace, A interface trace, Abis

interface trace, SS7 interface trace and SCCP trace.




2-2

2.2 Um Interface Trace

2.2.1 Functions

Um interface trace function is to trace the signaling over the radio interface of the cell in

the BSC Maintenance System. In actual application, the Um interface is traced by the

test MS and software. The Um interface trace in the maintenance system is not applied

that frequently, and will be briefly described in this chapter.

2.2.2 Operations

1) Start the BSC Maintenance System, select the menu item [Trace/GSM

Tracing/GSM Interface Tracing], and an interface will pop up, as shown in

Figure 2-2:

Figure 2-2 GSM interface trace

2) Select the Um interface trace, module No., click <OK>, and an interface will pop

up, as shown in Figure 2-3.




2-3

Figure 2-3 Um interface trace

3) Input the cell number, TRX number and channel number, and the traced

messages over the Um interface will be listed, as shown in Figure 2-4.

Figure 2-4 Um interface trace message

4) Query saved messages through GSM Tracing Review

The messages traced and saved (note: they can be queried from other maintenance

consoles only when the file header is modified with some edit tools) can be queried by




2-4

selecting [Trace/GSM Tracing/GSM Tracing Review] in the BSC Maintenance System.

Select the message file to be queried in the pop-up window, and click <Open>; or copy

the saved GMT files to another terminal, and query them through OMC LocalWS.

Figure 2-5 GSM interface tracing review

2.2.3 Options

Cell Number: Number of the cell with the Um interface to be traced, decimal.

TRX Number: TRX number to be traced, decimal.

Channel Number: In use.

RR management procedure: Select the item, and the messages of this type will be

listed in the message trace window, like system information.

Mobility Management (MM) procedure: Displaying MM related messages, like

messages in TMSI reallocation procedure, authentication procedure and identification

procedure.

Call Control (CC) and call related Supplementary Service (SS) procedure: Displaying

the messages related to call procedure and SS.

Call-unrelated SS procedure: Such as REGISTER message that is call-unrelated

supplementary service message.

Short Message procedure: Short message related signaling procedures displayed in

the trace window.




2-5

2.2.4 Examples

The Um interface trace in the maintenance system is hardly applied, No example is

provided

2.3 Abis Interface Trace

2.3.1 Functions

In actual deployment and maintenance process, such faults as call drop, handover

failure, MS access-to-network failure and poor quality of speech frequently occur. In

these cases, it is necessary to locate the faults through signaling procedure analysis.

Therefore, Abis interface trace is an important approach to locate problems in the field.

2.3.2 Operations

1) Start the BSC Maintenance System, select the menu item [Trace/GSM

Trace/GSM Interface Trace], and an interface will pop up, as shown in Figure 2-6.


2) Select the module No. and Abis interface, and the interface will pop up, as shown

in Figure 2-7.




2-6

Figure 2-7 Abis interface trace

3) Select the Cell Number, TRX Number, click <OK>, and the traced messages over

the Abis interface will pop up, as shown in Figure 2-8.

Figure 2-8 Abis interface trace messages

4) Query saved messages through GSM Tracing Review




2-7

The messages traced and saved (note: they can be queried from other maintenance

consoles only when the file header is modified with some edit tools) can be queried by

selecting [Trace/GSM Tracing/GSM Tracing Review] in the BSC Maintenance System.

Select the message file to be queried in the pop-up window, and click <Open>; or copythe saved GMT files to another terminal, and query them through OMC LocalWS.

Figure 2-9 GSM interface tracing review

2.3.3 Options

Cell Number: Number of the cell whose Abis interface is to be traced, decimal.

TRX Number: TRX Number of the Abis interface to be traced, decimal; if it is not

selected, the Abis signaling of the entire cell will be traced.

Channel Number: In use.

Measurement report: Select [Test Report], and the measurement report messages will

be listed in the trace message window.

Radio link layer management procedures: Select [Radio Link Layer Management

Message], the messages of this type will be listed in the trace window. They include:

Link establishment indication (EST IND), link establishment request (EST REQ and

EST CONF), link release indication, (REL IND), link release request (REL REQ and

REL CONF), transmission of a transparent L3-Message in acknowledged mode (DATA

REQ), reception of a transparent L3-Message in acknowledged mode (DATA IND),

transmission of a transparent L3-Message in unacknowledged mode (UNIT DATA

REQ), reception of a transparent L3-Message in unacknowledged mode (UNIT DATA

IND), and link error indication (ERROR IND).




2-8

Dedicated channel management procedures: Channel activation (CHAN ACTIV and

CHAN ACTIV ACK/NACK), channel mode modify (MODE MODIFY and MODE

MODIFY ACK/NACK), handover detection (HANDO DET), start of encryption (ENCR

CMD), deactivate SACCH (DEACT SACCH), radio channel release (RF CHAN RELand RF CHAN REL ACK), MS power control (MS POWER CONTROL), transmission

power control (BS POWER CONTROL), connection failure (CONN FAIL IND), physical

context request (PHYS CONTEXT REQ, PHYS CONTEXT CONF) and SACCH

information modify (SACCH INFO MODIFY).

Common channel management procedures: channel request by MS (CHAN REQ),

paging (PAG CMD), deletion indication (DELETE IND), CCCH load indication (CCCH

LOAD IND), broadcast information modify (BCCH INFO), short message cell broadcast

(SMS BROADCAST REQ, CBCH LOAD IND and SMS BROADCAST CMD), and

immediate assignment (IMM ASS CMD).

TRX management procedures: radio resource indication (RF RES IND), SACCH filling

information modify (SACCH FILL), flow control (OVERLOAD), and error reporting

(ERROR REPORT).

2.3.4 Examples

Figure 2-10 illustrates a complete Abis interface message procedure.

Figure 2-10 Abis interface messages




2-9

Double click an Abis interface message in the maintenance system, and the type and

the detailed description of this message will be listed.

A complete call procedure will be given based on the messages above:

1) CHAN_RQD: This message is sent from MS to BTS to request for channel. Then,

BTS transfers it to BSC. Key field in the message: Access Delay (2 bytes),

indicating the access location of MS (from the BTS).

2) CHAN_ACTIV: Sent back to BTS from BSC. Key fields: Timing Advance (2 byte),

MS Power (2 bytes) and BS Power (2 bytes).

3) CHAN ACTIV_ACK: It is sent from BTS to BSC. No special point in it is to be

concerned.

4) IMMEDIATE ASSIGN_COMMAND: It is used for BSC to assign SDCCH to MS.

Key fields: Timing Advance.

5) EST_IND: It is sent from BTS to BSC. Double click on the message, and thedetailed information about it will be displayed: Key fields: Message Type (like CM

Service Request), type of the message; Identity digit (TMSI allocated to this

domain), and the encryption domain.

6) DATA_REQ: Transparent L3-Message, generally including authentication request

and classmark request messages.

7) DATA_IND: Authentication response, classmark response and SETUP messages

(with called number provided). Key field: SETUP message.

8) MEAS_RES: Measurement reporting message, including SDCCH and TCH

measurement messages. The detailed content including:

z Channel TYPE: SDCCH or TCH.

z Time Slot Number: Timeslot No.

z Uplink measurement: Uplink measurement report, including uplink Rx quality and

Rx level.

z RXLEV_FULL_UP: When the uplink does not use DTX, the uplink Rx level is the

value of this domain.

z RXLEV_SUB_UP: When the uplink uses DTX, the uplink Rx level is the value of

this domain.

z RXQUAL_FULL_UP: When the uplink does not use DTX, the uplink Rx quality is

the value of this domain.z RXQUAL_SUB_UP: When the uplink uses DTX, the uplink Rx quality is the value

of this domain.

z BS POWER: Transmit power of the BTS.

z Actual Timing Advance: Timing advance.

z L3 information: Downlink measurement values of the service area and its 6

neighbor cells reported.




2-10

2.4 A Interface Trace

2.4.1 Functions

In actual deployment and maintenance process, such faults as the interconnection

coordination between the BSC of Huawei and MSC of another manufacturer via the A

interface, A interface related MS access-to-network failure, assignment failure, call

drop, handover failure, and poor quality of speech frequently occur. In these cases, it is

necessary to locate the faults through the trace and analysis of the A interface signaling

procedure.

2.4.2 Operations

I. Message trace

Start the BSC Maintenance System, select [Trace/GSM Trace/GSM Interface Trace],

and an interface will pop up, as shown in Figure 2-11.


Select A Interface and the corresponding module No., click <OK>, and an interface will

pop up, as shown in Figure 2-12.




2-11

Figure 2-12 Interface trace message filter parameter selection

Generally, select Connectionless Message, DTAP Message and BSSMAP without the

input of SCCP No, click <OK>, and a traced message over the A interface will pop up,

as shown in Figure 2-13.

Figure 2-13 A interface trace message




2-12

II. Message view

Select the message to be viewed in the Trace Message window, double click and the

details of the message will be listed, as shown in Figure 2-14.

Figure 2-14 Details of A interface trace message

III. Message saving

The A interface messages traced can be saved in the Operations and Maintenance

terminal. Right click in the message trace window, and a menu will pop up, as shown in

Figure 2-15.




2-13

Figure 2-15 A interface trace message saving

Select [Save] in the shortcut menu, and an interface will pop up, as shown in Figure

2-16.

Figure 2-16 Input the file name to save the A interface message

Input the file name in the dialog box, click <OK>, and the A interface messages traced

will be saved under the directory: C: \OMC\Shell\G3BSC32.10100.04.1120A (file folder




2-14

with the name of BSC version No.)\trace on the Operations and Maintenance terminal,

and the suffix of the file name is "GMT".

IV. View saved messages through GSM Tracing Review

The saved messages can be viewed by clicking [Trace/GSM Tracing/GSM Tracing

Review]. Select the message file to be view and click <Open>, as shown in Figure 2-17.

Figure 2-17 A interface tracing review

2.4.3 Options

Connectionless messages: Paging and circuit management messages.

DTAP messages: Transparently transmitted messages in the CC layer and MM layer.

BSSMAP: A interface messages specified under the GSM 0808 protocol.

SCCP No.: connection No. of SCCP in the connection message, generally not required.

2.4.4 Examples

Figure 2-18illustrates a complete A interface PAGING message.




2-15

Figure 2-18 Details of the PAGING message over the A interface

1) Displayed in SCCP Message Type. It is a N_UNIDATA_INDICATION message.

2) Displayed in the BSSMAP Message Type, it is a PAGING message.

3) The paging IMSI included in the IMSI code of this message is 460005050907827.

4) The location area code of the paging message displayed in LAC is 8506

(hexadecimal).




2-16

2.5 SS7 Trace

2.5.1 Functions

SS7 is divided into different modules based on its functions. Each module completes

relatively independent functions, and transmits service information and network

management information through primitives. The architecture is shown in Figure 2-19

OMAP

TCAP

SCCP

MTP

I

S

U

P

T

U

P

a b c

de

f

Note: a,b,c: MPT service primitive

e,d: network service primitive

f f: TC-primitive

Figure 2-19 Architecture of SS7

The function of each part in this architecture is briefly described as follows:

1) Message Transfer Part (MTP), including 3 functional levels: signaling data link

(physical layer, MTP L1), signaling link function (link layer, MTP L2), and signaling

network function (network layer, MTP L3).

2) Signaling Connection Control Part (SCCP): Enforcing the function of the MTP part,

and providing the function equal to the OSI network layer..

3) Telephone User Part (TUP): Stipulating call establishment and release related

functions and programs, and supporting some SS.

4) ISDN User Part (ISUP): Providing functions for speech and non-speech switching

in ISDN, so as to support basic bearer services and SS.

5) Transaction Capability Application Part (TCAP): Providing a group of procedures

and functions for the communications of a series of application services.

6) Operation and Maintenance Application Part (OMAP): Providing such functions as

SS7 monitoring, measurement and management, as well as protocol test and

monitoring online.

The architecture of SS7 is described through primitives as follows:

1) MTP service primitives




2-17

MTP_TRANSFER request: Used for SCCP to transfer signals and messages to MTP.

MTP_TRANSFER indication: Used for MTP to transfer signals and messages to SCCP.

MTP_PAUSE indication: Used for MTP to notify TUP that it cannot transfer themessage to the destination.

MTP_RESUME indication: Used for MTP to notify TUP that it is capable to provide MTP

services to the destination.

MTP_STATUS indication: Used for MTP to notify TUP that it can partially (congestion)

provide MPT services to the destination. It is also used to notify MS the cause whether

the remote MS is available or not.

MTP_RESTART indication: Upon the completion of MTP restart, it informs the local

MTP users of the end of the MTP restart, and indicates whether a signaling point isavailable nor not.

2) Network service primitives

Connectionless service primitives:

N_UNITDATA request: A SCCP user requests the SCCP to transmit data to another

SCCP.

N_UNITDATA indication: SCCP notifies users that the user data are sent to the

destination.

N_NOTICE indication: SCCP notifies the originating user that the message cannot be

sent to the destination.

Connection-oriented service primitives:

N_CONNECT request: The message from the calling SCCP User to SCCP is used to

start the connection establishment procedure to establish a signaling connection.

N_CONNECT indication: It is sent from SCCP to request the called SCCP User to

establish signaling connection with the calling MS.

N_CONNECT response: It is sent from SCCP to notify the called SCCP User that itagrees to establish signaling connection.

N_CONNECT acknowledgement: The calling SCCP notifies the calling MS to confirm

the establishment of the signaling connection.

N_DATA request: SCCP User requests SCCP to transfer data.

N_DATA indication: SCCP notifies the SCCP User that the user data have been sent to

the destination.

N_DISCONNECT request: SCCP User requests SCCP to reject or terminate the

signaling connection.




2-18

N_DISCONNECT indication: SCCP notifies the SCCP User that the signaling

connection has been rejected or terminated.

2.5.2 Operation and Options

I. Overview

Trace messages based on a certain signaling link, capture and save all or part

messages through the signaling link. It provides functions to open and display the files

traced and saved for the SS7 messages. Log in the BSC Maintenance System, select

the menu item [SS7 Maintenance/SS7 Message Trace/SS7 Message Tracing], and an

interface will pop up, as shown in Figure 2-20.

Figure 2-20 SS7 message trace

The functions of the submenus under [SS7 Message Trace] are listed in Table 2-1.

Table 2-1 Submenus under the menu item [SS7 Message Trace]

Menu item Function

SS7 Message Tracing Trace a certain SS7

SS7 Message Review Open a SS7 message trace file in the saving media

II. Functions

This function is used to trace messages based on a certain signaling link, capture all or

part of the messages through this link. It can also be used to view whether the signaling




2-19

coordination between offices is correct in case of problems in signaling coordination

between different systems.

III. Operations

Select the menu item [SS7 Maintenance/SS7 Message Trace/SS7 Message Traced],

and an interface will pop up, as shown in Figure 2-21.

Figure 2-21 Setting for SS7 message tracing

IV. Interface description

Module No.: No. of the module where the SS7 link is located.

Link No.: No. of the link to be traced.

Message Type: Message type to be observed. The messages with the type to be

selected will be listed in the trace results. Table 2-2 shows the descriptions of the

message types.

Table 2-2 Meanings of message types

Message type Meaning

SNM Signaling network management message, MPT L3-message.

SLT Signaling link test message, MTP L3-message.

SCCP Signaling connection and control part message.

TUP TUP message, not used by BSC.

ISUP ISDN user part message, not used by BSC.

MT Maintenance test message.

UNKNOWN Unknown message.

L2_CHANGE MTP L2-message.




2-20

Filter: It is used to filter messages of the specified type. For instance, you can observe

a message sent to a signaling point by setting the value of DPC_Filter. Once a filter is

selected, the corresponding box in [Parameter] will become valid, and you can input the

specified value. Table 2-3 shows the details of the filters.

Table 2-3 Meanings of filters

Filter Meaning

NI_Filter Network indicator (NI) filter: International-0, international reserved-1, national –2and national reserved-3.

OPC_Filter Original signaling point code (OPC) filter: The OPC value is required.

DPC_Filter Destination signaling point code (DPC) filter: The DPC value is required.

H1_Filter H1 filter in MSU.

H0_Filter H0 filter in MSU (the specified messages can be filtered by setting both filters H1and H0).

SLS_Filter Signaling link selection (SLS) code filter: SLS value is required.

CIC_Filter Circuit identification code filter: CIC value is required.

Direction_Filter Signaling direction filter: 0 for Tx; 1 for Rx.

If the user selects the check box "Save to file (No Extension Name)", and inputs the file

name (without suffix) in the text box, the system will trace the information and save it for

future review and analysis.

After setting all the trace items, click the <OK> button to start tracing. If an item is not

set correctly, e.g., to trace a link actually not installed, the system will prompt "Sorry.

Tracing MSU failed".

If the trace item is correctly set, a window shown in Figure 2-23 will pop up, indicating

the start of trace.




2-21

Figure 2-22 SS7 trace window

The title of the window shows the No. of the module where the link being traced is

located and the link ID.

Once a message conformable to the trace requirement is traced, it will be listed in the

trace window. When the number of messages exceeds the display range in the window,

you can use the scrollbar for browse. The items in the message list are described asfollows:

[Service]: Service type of the messages. Figure 2-22 lists TEST messages. The

symbols on the left of the window refer to the directions in which the messages are sent.

"<" for message sending, and ">" for message receiving. At the same time, the

messages in blue are that sent, and the messages in black are that received.

[SubSer]: Sub service-type of the message. "INT" for national reserved network.

[Time]: Time the message is generated. It is a value relative to the start of trace.

[H1H0]: Name of the message.

[CIC/SLC]: CIC/SLC value in the message, indicating different meanings based on

different message structures.

[SLS]: Value of the signaling link selection code.

[OPC]: OPC value in the message structure.

[DPC]: DPC value in the message structure.

[Signal Message...]: Parameters in the message, denoted by hexadecimal numerals.




2-22

To pause message trace, press <Space> and the window will display the message in

"Pause" state and the number of "Pause" times and time. Press <Space> again, and

the window will display to "Continue" the message, and the number of "Resume" times

and time, and the message trace will be resumed.

When the personnel have some knowledge about the SS7 message structure, they can

get the message Tx/Rx and contents by analyzing the trace results.

Service SubSer Time H1H0 CIC/SLC SLS

SCCP INT 471 009

OPC DPC Signal Message...

0B51 0B5A 06 01 00 41 00 01 06 01 00 03 05 04 11

The message is a location update reject message. The OPC is 0B51, and DPC is 0B5A.

"06" in the message parameter refers to the SCCP DT1 message. "01 00 41" is the

destination local reference. "00" is the segmentation/reassembly mark, indicating there

is no more data. "01" is user data offset, and "06" is user data length. "01 00 03" refers

to the DTAP message, and the message length "03" is DTAP. "05 04 11" refers to MM

(05) sublayer location update rejected (04), and the cause is system fault (11).

Close the window, and the trace will be stopped.

2.5.3 Examples

Messages traced through the SS7 trace function provided by the BSC Maintenance

System:




2-23

Figure 2-23 SS7 message tracing window

Descriptions of the messages in Figure 2-23.

Select a message, press <Enter> or double click on it to view the details of themessage content. The message with ">" before, i.e., the message in black, indicates

that the formal message signal units (MSU) are received from this link.

The message with "<" before, i.e., the message in blue, indicates that the formal

message signal units (MSU) are sent from this link.

The messages with ">" or "<" are messages in L2 and L3 of MTP. Generally, they are

generated in case of link broken or link locating procedure or signaling link

measurement. They are important for the analyzing link broken cause and locating

failure cause.

Contents of MTP L2-message:

TIME: time (unit: 10ms). It is relative time, i.e., the time interval from the start of the

signaling link tracing to the generation of the message. The maximum value is 65535. It

is counted from 0 upon the reach to the maximum value.

TYPE: message type. MTP L2-command (MTP_L2_CMD) or MTP L2-response

(MTP_L2_REPORT) MTP L2-command is sent from the CPU to a board, and MTP

L2-response is reported from the board to the CPU.




2-24

PARA: Command or response parameter. It refers to a board type. 00 is for the LPN7

board, and 01 for SS7 board. The parameters followed are commands or command

responses, please refer to the details of the messages.

Note:

Only the content following PARA is used in the examples for the messages of this type.

The first message in the "SS7 Message Tracing window" can be briefly described as

follows: In the 19.7th second since the opening of the message tracing window, MTP

delivers a STOP command to this signaling link.

MSU transmitted in the link:

Service: Service indication of the message. Test refers to signaling link test messages,

MPT refers to the signaling network management messages in MTP, and TUP, ISUP

and SCCP refer to the messages in TUP, ISUP and SCCP respectively.

SubSer : Sub service field, i.e., NI. NAT is for national network, and INT for international

network.

Time: time (unit: 10ms), it is a relative time, i.e., the time interval from the start of the

signaling link trace to the generation of the message. The maximum value is 65535. Itis counted from 0 upon the reach to the maximum value.

H1H0: Message header code, used to identify a specific message.

CIC/SLC: CIC for the TUP and ISUP messages, SLC for the MTP messages, and SLS

for the SCCP messages.

SLS: Signaling link selection code. It is displayed for the ISUP messages only.

OPC: Originating signaling point code in the message.

DPC: Destination signaling point code in the message.

Signal Message: Contents of the message.

2.6 SCCP Signaling Trace

2.6.1 Functions

SCCP, signaling connection control part in SS7, is an important approach to locate and

solve problems in deployment, maintenance and debugging. The OMC of Huawei




2-25

provides the following functions for SCCP maintenance: Message Trace, Management

Options and Status Query. The message trace function can be used to trace a SCCP

message to be analyzed conveniently, and improve the efficiency in problem solution.

Select the menu item [SS7 Maintenance/SCCP Maintenance], and an interface will popup, as shown in Figure 2-24.

Figure 2-24 SCCP maintenance window

2.6.2 Operations

SCCP signaling message trace function is an important approach to locate problems

and provides reference for operation verification in deployment, maintenance and

debugging. It is the most commonly used function in SCCP maintenance.

I. Trace parameter setting

Select the menu item [SS7 Maintenance/SCCP Maintenance/SCCP Message Trace] in

the BSC Maintenance System, and an interface will pop up, as shown in Figure 2-25.




2-26

Figure 2-25 SCCP message trace

II. Start tracing

Start tracing after setting all the trace items. If an item is not correctly set, e.g., the digits

of signaling point code is not enough, the system will prompt "Please input 3 digits of

signaling point code".

If the item is correctly set, a window indicating the start of trace will pop up, as shown in

Figure 2-26.




2-27

Figure 2-26 SCCP DPC message trace

The title bar of the window displays the NI and SPC of the message being traced.

"START TRACE NO.7 SUCCESS !" means the trace is successful.

The message once traced to be conformable to the trace requirement will be added to

the window. When the number of messages exceeds the display range, you can use a

scroll bar for browse. The meanings of the items in the message list are given as

follows:

[MsgType]: Type of the message.

[Signal Message...]: Content of the message, denoted by hexadecimal numerals.

III. Pause/Resume Tracing

To pause message trace, press <Space> and the window will display the message in

"Pause" state and the number of "Pause" times, and time. Press <Space> again, the

window will prompt to "Continue" the message, and the number of "Resume" times,

and time. The message trace will be resumed.




2-28

2.6.3 Options

Figure 2-27 SCCP message trace

[Module No.]: Fixed as 1 for BSC.

[NI]: Indicating the signaling network where the remote signaling point is located. It

includes "International active", "International standby", "National active" and "National

standby". Generally

[SPC]: 6-digit hexadecimal code, queried from the data management console. It refers

to the peer MSC SPC.

Whether [NI] and [SPC] are valid is independent on the trace object selected.

Select the message type to be observed, and the messages of the type will be listed in

the trace results.

Trace message to far-end signaling point: Message sent to the far-end signaling point.

Trace message from far-end signaling point: Message sent from the far-end signaling

point.

Trace MPT messages addressed by GT: SCCP provides several addressing modes.

Select this item, and only the messages addressed by GT will be displayed.

Trace subscriber messages: Messages of SCCP subscribers, like TCAP message.

2.6.4 Examples

The following figure show the SCCP messages traced when MS initiates a call.




2-29

Analysis for the bytes in the CR messages ("X" for the BITS to be analyzed, and "?" for

those not to be analyzed for the moment)

Standard message format Message content Byte

????XXXX SI ????0011 Service indicator

??XX???? ??00???? Invalid field

??XXXXXX NI 11?????? Network indicator

0xC3

XXXXXXXX

??XXXXXXDPC

10100010

??000000

Destinationsignaling PointCode

00B2

XX??????

XXXXXXXX

????XXXX

OPC

01??????

00110000

????0000

Original signalingPoint Code

00C1

XXXX???? SLS 1110????

Signaling linkselection code

0E

0x50

0x34

0x0A

0XC0

XXXXXXXX Message type 00000001 CR message 0x01

3 bytes Source LocalReference

010041h Originating localcode

0x01

0x00

0x41

????XXXX Protocol type ????0010 Services of Class 2

XXXX???? 0000???? Invalid field

0x02

1 byteSize variablemandatorypointer

00000010Called addresspointer

0x02




2-30

Standard message format Message content Byte

1 byte Any part startpointer

00000110Pointing to callingaddress

0x06

1 byte Size indicator 04hLength of calledaddress

0x04

???????XSignaling pointindicator

???????1 SPC included

??????X?Subsystemindicator

??????1? SSN included

??XXXX?? GT indicator ??0000?? GT not included

?X?????? Routing indicator ?1??????DPC and SSNrouting

X??????? 0??????? National reserved

0x43

2 bytes SPC 0X5034 OPC 0x5034

1 byte SSN 0xfe A interfacesubsystem

0xFE

1 byte Any parameter name

0x04 Calling address 0x04

5 bytes Any parameter

name

04 43 28 10

FE

Format same as

the called address

04 43 28

10 FEh

1 byte Any parameter name

0x0F SCCP user data 0x0F

1 byte Any parameter size

0x1c

SCCP user datasize (followed byBSSAPmessages)

0x1c



Signaling Analysis ManualM900/M1800 Base Station Subsystem Chapter 3 System Information

3-1

Chapter 3 System Information

3.1 Overview

System information includes the major radio network parameters on Um interface.

Specifically, it includes network identification parameter, cell selection parameter,

system control parameter and network function parameter. By receiving system

information, MS can properly access the network, perform network selection, fully

utilize the various services provided by the network and communicate with the

network normally. Common System information can be classified into two parts, thesystem information transmitted on BCCH and the system information transmitted on

SACCH. The former includes SYSTEM INFORMATION TYPE 1, 2, 2bis, 2ter, 3 and 4.

The latter includes SYSTEM INFORMATION TYPE 5, 5bis, 5ter, 6, 7 and 8.

SYSTEM INFORMATION TYPE 9 includes the control information for BCCH. If

SYSTEM INFORMATION TYPE 9 is used, the receiving location of it is indicated in

SYSTEM INFORMATION TYPE 3. Generally, it is not used.

If the system supports GPRS, SYSTEM INFORMATION TYPE 13 should be used.

The following describes common system information in detail.

Note:

1) The system information transmitted on BCCH belongs to common channel information. The system

information transmitted on SACCH belongs to TRX management information. When interface tracing is

to be performed through BSC Maintenance System, the options of common channel information and

TRX management information must be selected. Only in this way can all system information be

observed.

2) SYSTEM INFORMATION TYPE 1, 2, 2ter, 3, 4, 5, 5ter and 6 can be delivered to cells by default. 2bisand 5bis are mainly transmitted over DCS1800 cells conditionally.




3-2

3.2 Detailed Description of System Information

3.2.1 SYSTEM INFORMATION TYPE 1

I. Purpose

SYSTEM INFORMATION TYPE 1 mainly describes RACH control information and CA

(Cell Allocation table). It is transmitted on BCCH.

II. Information content

SYS INFO 1 - - Cell Channel Desc.

-- RACH Control Para.

1) CA

BSC supports the configuration of up to 64 cell frequencies. Due to the restriction of

cell channel description formats, actually, cell frequencies cannot be configured

randomly.

BSC selects different cell channel description formats according to the actual

frequency configuration.

There are five channel description formats with the format ID of bit128, bit127, bit124,

bit123 and bit122, which are respectively determined by the second byte in the cellchannel description, as shown in Table 3-1, Table 3-2.

Table 3-1 Cell Channel Description Formats

8 7 6 5 4 3 2 1

Cell Channel Description IEI octet 1

Bit

128

Bit

127

0

Spare

0

Spare

Bit

124

Bit

123

Bit

122

Bit

121

octet 2

… … … … … … … … …

Bit

008

Bit

007

Bit

006

Bit

005

Bit

004

Bit

003

Bit

002

Bit

001

octet 17

Table 3-2 Cell channel description formats

Bit128 Bit127 Bit124 Bit123 Bit122 Format notation

0 0 X X X Bit map 0

1 0 0 X X 1024 range




3-3

Bit128 Bit127 Bit124 Bit123 Bit122 Format notation

1 0 1 0 0 512 range

1 0 1 0 1 256 range

1 0 1 1 0 128 range

1 0 1 1 1 Variable bit map

The corresponding number of the cell configurable absolute frequencies of each cell

channel description format is not the same. The number of configurable absolute

frequencies in one cell (the same frequencies and illegal frequencies excluded), and

ARFCN (i) (i=1,...,n) denotes the corresponding radio frequency, the number of

configurable frequencies of each channel description format will be as follows.

Bit map 0

Bit map 0 can be used for 900M frequency. The actual number of cell configurable

frequencies can reach 64. Moreover, the frequencies can be configured randomly, so

long as they satisfy "1 ≤ ARFCN (i) ≤ 124".

1024 range format

When this format is adopted, the actual number of cell configurable frequencies is

less than or equal to 16 (n≤16), but the frequencies can be freely configured. For

900M, 1 ≤ ARFCN (i) ≤ 124. For 1800M, 512 ≤ ARFCN (i) ≤ 885.

512 range format


less than or equal to 18 (n ≤ 18), but the following condition should also be satisfied.

Assuming that m denotes the maximum interval between two configured frequencies,

"m < 512" should be satisfied.

256 range format


less than or equal to 22 (n≤22), but the following condition should also be satisfied.


"m<256" should be satisfied. For example, when this format is adopted, frequency

512 and frequency 812 cannot be configured at the same time.

128 range format


less than or equal to 29 (n≤29), but the following condition should also be satisfied.





3-4

"m<128" should be satisfied. For example, when this format is adopted, frequency

512 and frequency 712 cannot be configured at the same time.

Variable bit map

When this format is adopted, the actual number of cell configurable frequencies can

also reach 64, but the following condition should also be satisfied. Assuming that m

denotes the maximum interval between two configured frequencies, "1≤m≤111"

should be satisfied. For example, it is feasible to configure the frequencies 512, 513,

514, ..., 575 (increased by 1, total 64 frequencies), but it is unfeasible to configure the

frequencies 512, 514, 516, ..., 638 (increased by 2, total 64 frequencies).

2) RACH control information

RACH control information includes the following parameters.

MAX retrans indicates the maximum number of retransmissions of the Channel

Request message before MS receives an Immediate Assignment message, i.e. the

number of channel requests that can be sent by MS is "M + 1". It is a 2-bit code. The

maximum number of retransmissions that corresponds to 0~3 is 1, 2, 4 and 7

respectively.

Tx_integer (Extended transmit TS number) indicates the number of timeslots

between two successive retransmissions when MS continuously sends multiple

Channel Request messages

CBA (CELL_BAR_ACCESS) indicates whether MS is allowed to access the currentcell. It is a 1-bit code. "0" indicates cell access is allowed, and "1" indicates that cell

access is barred. This parameter has no impact upon handover access.

AC denotes access restricted user level. AC can be classified into AC 0~AC 9 and AC

11~AC 15. Generally, each MS is allocated with an AC. Each AC is indicated by one

bit. "1" indicates that the MS of the corresponding AC is not allowed to access the

current cell, and "0" indicates the MS is allowed to access the current cell. Compared

with the MSs of AC 0 ~AC 9, the MSs of AC 11~AC15 have higher access priorities.

However, between the ACs within 0~ 9, or the ACs within 11~15, different ACs do not

denote different access priorities.

RE (bit allowed for call reestablishment) indicates whether the network allows

connection reestablishment after MS initiates the call reestablishment procedure. It is

a 1-bit code. "0" indicates that the current cell allows call reestablishment, and "1"

indicates that the current cell does not allow call reestablishment.

EC (bit allowed for emergency call) indicates whether MS is allowed to initiate an

emergency call in the case that the MS has no SIM card or its AC is disabled by the

current cell. It is a 1-bit code. "0" indicates that emergency call is allowed, and "1"

indicates that emergency call is not allowed (except the MSs of AC 11~ AC 15).




3-5

Note:

The extend transmit TS number is a random value, and belongs to the collection of {S, S+1,....S+T-1}.

The measurement unit is TDMA frame. Of the collection, S depends on common channel configuration,

and T denotes the extend transmit TS number (Tx_integer). See Table 3-3 for the values of S.

Table 3-3 S and T Parallelism

Tx_integer CCCH uncombined CCCH combined

3, 8, 14, 50 55 41

49. 16 76 52

5, 10, 20 109 586, 11, 25 163 86

7, 12, 32 217 115

Note:

When satellite transmission is adopted, to lessen the impact of satellite Tx delay, it is recommended that

“MAX retrans” is set as "4" and “Tx_integer” is set as "32".

3.2.2 SYSTEM INFORMATION TYPE 2, 2bis and 2ter

I. Purpose

SYSTEM INFORMATION TYPE 2 mainly describes RACH control information, NCC

permission and CA of the neighbor cells (namely, BA1 table). It is transmitted on

BCCH. Generally, SYSTEM INFORMATION TYPE 2, 2bis and 2ter respectively

describe different parts of BA1. By reading and decoding BA1 table, MS canimplement cell reselection in idle mode. The GSM900 MS in Phase 1 only recognizes

the neighbor cell frequencies described in SYSTEM INFORMATION TYPE 2 and

skips those contained in 2bis and 5ter.

Type 2bis mainly describes RACH control information and the extended frequency

allocation table of neighbor cells (part of BA1 table). It is optional, and is transmitted

on BCCH. Generally, because the number of frequencies described in the frequency

allocation table in SYSTEM INFORMATION TYPE 2 is limited, SYSTEM

INFORMATION TYPE 2bis contains the information of other frequencies in BA1 which

are in the same frequency band as SYSTEM INFORMATION TYPE 2.




3-6

Type 2ter mainly describes the extended frequency allocation table of neighbor cells

(part of BA1 table). It is transmitted on BCCH. Only the multi-band MS can read this

information. The single-band GSM 900 or GSM 1800 MS will skip this information.

Because the frequencies contained in this information are in a frequency band whichis different from that of the current cell, such information is not needed by the

single-band MS.


SYS INFO 2 - - Neighbor Cell Desc.

- - NCC permitted

- - RACH Control Para.

SYS INFO 2 BIS - - Neighbor Cell Desc.


SYS INFO 2TER - - Neighbor Cell Desc.

1) BA1

BA1 (neighbor cell description) mainly describes the absolute frequency No. of the

BCCH TRX of the neighbor cell. Currently, the maximum number of neighbor cells

supported by Huawei is 32. Except the 5th bit (BA-IND) and 6th bit (EXT-IND) of the

second byte in BA1, the coding mode of other information is the same as that of the

cell channel description table (Refer to subsection 1) of 3.2.1 II).

EXT_IND (Extension Indication) is transmitted in SYSTEM INFORMATION TYPE 2

and 5, indicating whether there are other extended neighbor cell frequencies to be

transmitted in SYSTEM INFORMATION TYPE 2bis and 5bis. It is a 1-bit code. "0"

indicates that SYSTEM INFORMATION TYPE 2 and 5 already contain the complete

BA table, and "1" indicates that type 2 and type 5 only contain part of BA table.

BA Indication (BA_IND) is transmitted in SYSTEM INFORMATION TYPE 2 and 5. It

is a 1-bit code, and is used by MS to select the data in BA1 and BA 2 before or after

modification. In other words, if the neighbor cell relation of the current cell and theBA2 table is changed during a session, BA_IND in SYSTEM INFORMATION TYPE 5

will be 1 instead of 0. This indicates that MS should perform decoding for the

neighbor cell frequencies indicated in the SYSTEM INFORMATION TYPE 5 again.

2) NCC Permitted

NCC Permitted is transmitted in SYSTEM INFORMATION TYPE 2 and type 5. It is

an 8-bit code, and contains the collection of the NCCs to be measured by MS. In

other words, if 0≤N≤7 (N denotes the number of bits), MS will not measure the cell

level that satisfies "NCC=N", i.e. MS will not be handed over to the network that

satisfies "NCC=N". This parameter is mostly used in handover.




3-7


Refer to subsection 2) of 3.2.1 II for relevant description.

4) Extended neighbor cell description

It is mainly transmitted in SYSTEM INFORMATION TYPE 2ter and 5ter. Except the

5th

bit (BA-IND) and the 6th~7

thbit (Multiband Reporting), the codes of other

information are the same as those in cell channel description (Refer to subsection 1)

of 3.2.1 II for relevant description).

Multiband Reporting (MBR) is transmitted in SYSTEM INFORMATION TYPE 2ter

and 5ter. It is a 2-bit code, indicating whether MS reports neighbor cell information on

multiple frequency bands. It is applicable to multiband MS only. The details are listed

below.

Table 3-4 Meaning of multiband indication

Contents of multiband indication

(2 bits)Meaning

00MS should report the measurement result of 6 neighbor cells with thestrongest signal strength, no matter which frequency band it is allocatedwith.

01

MS should report the measurement result of 1 neighbor cell (if it existsand is permitted) which is allocated with a frequency band different fromthat of the current cell, and report the measurement result of 5 neighbor

cells which are allocated with the same frequency band as the currentcell.

10

MS should report the measurement result of 2 neighbor cells (if they existand are permitted) which are allocated with a frequency band differentfrom that of the current cell, and report the measurement result of 4neighbor cells which are allocated with the same frequency band as thecurrent cell.

11

MS should report the measurement result of 3 neighbor cells (if they existand are permitted) which are allocated with a frequency band differentfrom that of the current cell, and report the measurement result of 3neighbor cells which are allocated with the same frequency band as thecurrent cell.


I. Purpose

SYSTEM INFORMATION TYPE 3 mainly describes LAI, cell ID, RACH control

information and the parameters related to cell selection. It is mandatory, and is

transmitted on BCCH.




3-8


SYS INFO 3 - - Cell Identity

- - LAI

- - Control Channel Desc.

- - Cell Option (BCCH)

- - Cell Selection Para.


1) CGI

CGI (Cell Global Identity) is composed of LAI and CI, of which, LAI includes MCC,

MNC and LAC. SYSTEM INFORMATION TYPE 3, type 6 and type 4 contain all or

part of CGI information. Based on the received system information, MS decodes CGI

and decides whether to access the network in this cell according to the MCC and

MNC indicated by the CGI. CGI is also used to check whether the current location

area has changed, so that MS can determine whether the location updating

procedure need be initiated.

MCC, consisting of 3 decimal digits, is allocated worldwide in unified way. For

example, the MCC of China is 460. MNC, consisting of two decimal digits, is allocated

by the country in unified way. For example, the MNC of China Mobile is "00", and the

MNC of China Unicom is "01". LAC and CI, both consisting of 2 bytes, are arranged

by each GSM operator in unified way. Note that the value range of CI is

0X0001~0XFFFE, while 0X0000 and 0XFFFF are reserved.

2) Control channel description

Control channel description includes the following parameters.

IMSI attach and detach allowed (ATT) is used to notify MS whether the local cell

allows IMSI attach/detach procedure. ATT is a 1-bit code. "0" indicates that MS is not

allowed to initiate IMSI attach/detach procedure, and "1" indicates that MS must

initiate the IMSI attach/detach procedure.

CCCH CONF decides the integration mode of the CCCH in the cell. CCCH CONF is a

3-bit code. See Table 3-5 for detailed description.

Table 3-5 CCCH CONF code meaning

CCCH CONF (3 bits) Meaning

Number of CCCHinformation blocks

per BCCHmultiframe

000

CCCH uses a basic physical channel which is

not shared with SDCCH. 9




3-9

CCCH CONF (3 bits) Meaning

Number of CCCHinformation blocks

per BCCHmultiframe

001CCCH uses a basic physical channel which isshared with SDCCH.

3

010CCCH uses two basic physical channelswhich are not shared with SDCCH.

18

100CCCH uses three basic physical channelswhich are not shared with SDCCH.

27

110CCCH uses four basic physical channelswhich are not shared with SDCCH.

36

Others Reserved

BS_AG_BLKS_RES is used together with CCCH CONF to decide the number of

CCCH information blocks in each BCCH mutiframe of the current cell. After CCCH

CONF is set, BS AG BLKS RES will actually be used to arrange the occupancy ratio

between AGCH and PCH on CCCH. By adjusting this parameter, the bearing status

of AGCH and PCH can be balanced.

BS PA MFRAMS defines how many multi-frames make up a cycle of a paging

sub-channel. This parameter actually defines how many sub-channels the PCH of a

cell will be divided into. BS PA MFRAMS is a 3-bit code. The value range is 0~7,indicating that the number of multi-frames of a paging group cycled on the PCH is 2~9

respectively.

Periodic location updating timer (T3212) defines the frequency of periodic location

updating. It is an 8-bit code. The value range is 0~255, each unit of which denotes the

duration of six minutes. "0" indicates no location updating.

3) Cell option

Cell option includes the following parameters.

PWRC is used to notify MS whether the Rx level value obtained from the timeslots of BCCH TRX should be subtracted when it measures the Rx level in the frequency

hopping procedure. It is a 1-bit code. the Rx level value obtained from the timeslots of

BCCH TRX should not be subtracted, and "1" indicates that the Rx level value

obtained from the timeslots of BCCH TRX should be subtracted.

DTX indicates whether MS can use the DTX function. In SYSTEM INFORMATION

TYPE 3, it is a 2-bit code. In SYSTEM INFORMATION TYPE 6, it is a 3-bit code.

Radio_Link_Timeout is a 4-bit code. The value range is 0~15, and the

corresponding decimal value range is of 4~64. Every time MS receives a correct

SACCH message, 2 is added to this value. At the moment when MS should receive




3-10

an SAACH message, if it cannot correctly decode the SAACH message, 1 will be

subtracted from this value. If this value is 0, MS will report a radio link fault to BTS.

4) Cell selection parameters

Cell selection parameters have impact upon the behaviors of MS after it is powered

on. The major parameters are as follows.

Cell Reselection Hysteresis is used for cell reselection. MS cannot implement cell

reselection unless the level of the neighbor cell (Here, the neighbor cell and the

current cell do not belong to the same location area) minus the C2 of the current cell

is greater than the specified value of cell selection hysteresis. It is a 3-bit code. The

value range is 0~7, denoting 0dB ~14dB respectively.

MS_TXPWR_MAX_CCH indicates the Tx power used by MS before it receives a

power control command. It is a 5-bit code. The valid value range is 0~31, whichrespectively correspond to an MS output power.

RXLEV_ACCESS_MIN indicates the min. Rx level allowed for MS to access the

network. It is a 6-bit code. The value range is 0~63, denoting -110dBm~-47dBm

respectively.

ACS is used to notify MS whether to adopt C2 in the cell reselection procedure. It is a

1-bit code and is meaningless in SYSTEM INFORMATION TYPE 3. In SYSTEM

INFORMATION TYPE 4, if the value is 0, it indicates that MS adopts SI4 REST of

SYSTEM INFORMATION TYPE 4 to calculate C2-related parameters, or else, MS

adopts REST of SYSTEM INFORMATION TYPE 7 or type 8 to calculate c2-related

parameters.

NECI is used to notify MS whether the current cell supports half-rate services. It is a

1-bit code. "0" indicates that the current cell does not support half-rate services, and

"1" indicates the current cell supports half-rate services.

5) RACH control parameters



I. Purpose

SYSTEM INFORMATION TYPE 4 mainly describes LAI, RACH control information,

cell selection parameters and optional CBCH information. It is mandatory, and is

transmitted on BCCH. When the system supports cell broadcast, the optional IE

CBCH description and MA will be used, and will describe CBCH configuration and the

corresponding frequency information




3-11


SYS INFO 4 - - LAI

- - Cell Selection Para.


- - CBCH Channel Desc.(optional)

- - CBCH Mobile Allocation (optional)

- SI4 Rest Oct.

1) LAI

Refer to subsection 1) of 3.2.3 2 II for relevant description.

2) Cell selection parameters




4) CBCH description and CBCH MA

The two parameters are optional. When the system supports cell broadcast, CBCH

description contains the formation about CBCH configuration. When CBCH

description is in frequency hopping mode, CBCH MA is mandatory.

5) SI4 Rest Oct.

When ACS of the cell selection parameters is set as "No", the relevant parameters in

SI4 Rest Oct. will be used to calculate the value of the cell reselection parameter C2.

Cell reselection criteria:

z When PENALTY_TIME = 31,

C2=C1-CELL_RESELECT_OFFSET

z When PENALTY_TIME≠31,

C2=C1+CELL_RESELECT_OFFSET-TEMPORARY_OFFSET*H(P

ENALTY_TIME-T)

Where,

For the non-serving cell: When x<0, H(x)=0; when x>=0, H(x)=1

For the serving cell, H(x)=0

SI4 Rest Oct. contains the following parameters.

PI (Cell Reselection Parameter Indication) indicates whether MS adopts C2 as the

cell reselection parameter, and whether the parameters used for calculating C2 exist.




3-12

It is a 1-bit code. "0" indicates that C1 substitutes C2 and serves as the cell

reselection criteria. "1" indicates that parameters are extracted from system

information for calculating C2, which will serve as the cell reselection criteria.

CBQ (Cell Bar Qualify) is a 1-bit code. CBQ and CBA (CELL_BAR_ACCESS) jointly

form cell priority status. For details, refer to Table 3-6.

Table 3-6 Cell selection or reselection priority decided by CBQ and CBA

CBQ CBACell selection

priorityCell reselection

status

0 0 Normal Normal

0 1 Barred Barred

1 0 Low Normal

1 1 Low Normal

CRO (CELL_RESELECT_OFFSET) is used to manually correct C2. It is a 6bit code

and each bit stands for 0~126dB respectively. CRO, TO and PT are jointly used form

the manual correction value of C2.

TO (TEMPORARY_OFFSET): The value range is 0~7. Each level denotes 10dB.

0->0dB, 1->10dB…6->60dB, 7-> infinite.

PT (PENALTY_TIME): The value range is 0~31. Each level denotes 20s. 0->20s,…,

30->620s. When the value is 31, TO will be disregarded, and CRO will offset C2 with

a negative value.

3.2.5 System Information type 5, 5bis & 5ter

I. Purpose

SYSTEM INFORMATION TYPE 5 mainly describes the frequency information of

neighbor cells (namely, BA2). It is mandatory, and is transmitted on SACCH. Thedifference between SYSTEM INFORMATION TYPE 2 and type 5 is that the MS in

session state can read the frequencies described in SYSTEM INFORMATION TYPE

5 and report the relevant information of neighbor cells in the measurement report,

which will serve as the reference for handover. Likewise, the GSM900 MS in Phase 1

only recognizes the neighbor cell frequencies described in SYSTEM INFORMATION

TYPE 5 and skips those contained in 5bis and 5ter.

Type 5bis mainly describes the frequency information of neighbor cells (part of BA2).

It is optional, and is transmitted on SACCH. Generally, the number of frequencies

described in the frequency allocation table in SYSTEM INFORMATION TYPE 5 is




3-13

limited. Therefore, system information 5bis contains the information of other

frequencies in BA2 which are in the same frequency band as system information 5.

Type 5ter mainly describes the frequency information of neighbor cells (part of BA2),

and is transmitted on SACCH. Likewise, only the multiband MS can read this

information. The single-band GSM 900 or GSM 1800 MS will skip this information.


SYS INFO 5- - Neighbor Cell Desc.

SYS INFO 5 BIS - - Neighbor Cell Desc.

SYS INFO 5TER - - Neighbor Cell Desc.

1) Neighbor cell description

For relevant description, please Refer to subsection 1) of 3.2.2 II

2) Extended neighbor cell description

For relevant description, please Refer to subsection 4) of 3.2.2 II


I. Purpose

SYSTEM INFORMATION TYPE 6 mainly describes LAI, cell ID and the parametersused for describing cell functions. It is mandatory, and is transmitted on SACCH.


SYS INFO 6 - - Cell Identity

- - LAI

- - Cell Option (SACCH)

- NCC Permitted

1) CGI

Refer to subsection 1) of 3.2.3 II

2) Cell option


3) NCC permitted





3-14


I. Purpose

SYSTEM INFORMATION TYPE 7 is mandatory, and is transmitted on BCCH. It

contains cell reselection information.


SYS INFO 7---- SI 7 Rest Octets

SI 7 Rest Octets contains the parameters used by MS for cell reselection. It can also

contain the information of the parameter POWER OFFSET used by DCS1800 Class 3

MS.

The coding format of SI 7 Rest Octets is the same with SI 4 Rest Octets. See the

related description in "5) SI 4 Rest Oct" of 3.2.4.


I. Purpose

This system information is mandatory, and is transmitted on BCCH. It contains cell

reselection information.


SYS INFO 8 ---- SI 8 Rest Octets

SI 8 Rest Octets contains the parameters used by MS for cell reselection. It can also

contain the information of the parameter POWER OFFSET used by DCS1800 Class 3

MS.

The coding format of SI 8 Rest Octets is the same with SI 4 Rest Octets. See the

related description in "5) SI 4 Rest Oct" of 3.2.4.

3.3 Internal Handling of BSC

The internal handling of the BSC is given below:

1) The BSC retrieves cell frequencies in SYSTEM INFORMATION TYPE 1 from the

[Cell Allocation Table].

Table 3-7 shows the correspondence between the RACH control parameters in

SYSTEM INFORMATION TYPE 1 and the [System information table].




3-15

Table 3-7 Correspondence between RACH control parameters and the [System information table]

RACH control parameters in SYSTEMINFORMATION TYPE 1

System information table

Maximum number of retransmissions (MAX retrans)

MS MAX retrans

Number of slots to spread transmission (Tx_integer)

Tx_integer

Cell Barred for Access (CELL_BAR_ACCESS) CBA

Access Control Class (AC)Controlled by common access controlclass and Special access control class

Call reestablishment allowed (RE) Call re-establishment allowed

Emergency Call allowed (EC) EC allowed

Note:

“MAX retrans” and “Tx_integer” vary with the current traffic class of the cell if the BSC enables the cell

flow control function.

2) The BSC retrieves neighbor cell frequencies in SYSTEM INFORMATION TYPEs

2, 2bis and 2ter from the [BA1 Table]. Specifically, it retrieves NCC Permitted in

SYSTEM INFORMATION TYPE 2 from the “NCC permitted” field in the [System

information Table]. The RACH control parameters in SYSTEM INFORMATION

TYPEs 2 and 2bis are the same as that in SYSTEM INFORMATION TYPE 1, as

listed in Table 3-7.

3) The BSC retrieves CGI in SYSTEM INFORMATION TYPE 3 from the [BSC Cell

Table]. Table 3-8 shows the correspondence between the control channel

parameters in SYSTEM INFORMATION TYPE 3 and the [System information

table].

Table 3-8 Correspondence between the control channel parameters in SYSTEM INFORMATION TYPE

3 and the [System information table]

Control channel parameters in SYSTEMINFORMATION TYPE 3


Attach-Detach allowed (ATT) ATT

CCCH-CONF CCCH-CONF

BS_AG_BLKS_RES BS_AG_BLKS_RES

BS-PA-MFRAMS BS-PA-MFRAMS

T3212 T3212




3-16

Table 3-9 shows the correspondence between the cell options in SYSTEM

INFORMATION TYPE 3 and the [System information table].

Table 3-9 Correspondence between the cell options in SYSTEM INFORMATION TYPE 3 and the

[System information table]

Cell options in SYSTEM INFORMATION TYPE 3 System information table

Power control indicator (PWRC) PWRC

DTX indicator (DTX) DTX

Radio_Link_Timeout Radio Link Timeout

Table 3-10 shows the correspondence between the cell selection parameters in

SYSTEM INFORMATION TYPE 3 and the [System information table].

Table 3-10 Correspondence between the cell selection parameters in SYSTEM INFORMATION TYPE 3

and the [System information table]

Cell selection parameters in SYSTEMINFORMATION TYPE 3


Cell Reselection Hysteresis CRH

MS_TXPWR_MAX_CCH MS_TXPWR_MAX_CCH

RXLEV_ACCESS_MIN RXLEV_ACCESS_MIN

ADDITIONAL RESELECT PARAM IND ( ACS) ACS

HALF RATE SUPPORT (NECI) Half rate supported

The RACH control parameters in SYSTEM INFORMATION TYPE 3 are the same as

that in SYSTEM INFORMATION TYPE 1, as listed in Table 3-7.

4) The BSC retrieves Location Area Identification in SYSTEM INFORMATION

TYPE 4 from the [BSC Cell Table]. The cell selection parameters in type 4 are

the same as that in type 3, as listed Table 3-10. The RACH control parameters in

type 4 are the same as that in type 1, as listed in Table 3-7. The BSC receives

CBCH Channel from the [Carrier Configuration Table] and CBCH Mobile

Allocation from the [Frequency Hopping Table].

Table 3-11 shows the correspondence between SI 4 Rest Octets and the

[System information table].

Table 3-11 Correspondence between SI 4 Rest Octets and the [System information table]

SI 4 Rest Octets System information table

Cell Reselection Parameter Indicator (PI) PI




3-17

SI 4 Rest Octets System information table

CELL_BAR_QUALIFY (CBQ) CBQ

CELL_RESELECT_OFFSET (CRO) CRO

TEMPORARY_OFFSET (TO) TO

PENALTY_TIME (PT) PT

5) The BSC retrieves neighbor cell frequencies in SYSTEM INFORMATION TYPEs

5, 5bis and 5ter from the [BA2 (SACCH) Table].

6) The BSC retrieves CGI in SYSTEM INFORMATION TYPE 6 from the [BSC Cell

Table]. The cell options in this type are the same as that in type 3, as listed in

Table 3-9. The BSC retrieves NCC Permitted from the “NCC permitted” field in

the [System information table].

7) SI 7 Rest Octets are the same as SI 4 Rest Octets, as listed in Table 3-11.

8) SI 8 Rest Octets are the same as SI 4 Rest Octets, as listed in Table 3-11.



Signaling Analysis ManualM900/M1800 Base Station Subsystem Chapter 4 Location Update Procedure

4-1

Chapter 4 Location Update Procedure

4.1 Overview

In GSM system, MS location information need be known by HLR, VLR and MS, When

the location information changes, it is required that the relevant information in HLR,

VLR and MS should be consistent, which can be realized through the location

updating procedure. As the major procedure of location management, the location

updating procedure is always initiated on MS side.

The location updating procedure is a general procedure, and is used for 3 purposes,

i.e. normal location updating, periodic updating and IMSI attach.

The normal location updating procedure is used to update the registration of the

actual location area of MS in the network. The location updating type information

element in the LOCATION UPDATING REQUEST message shall indicate normal

location updating.

When the network indicates that MS is unknown in VLR, the normal location updating

procedure will be started, as a response to the MM connection establishment request.

In case that location updating is unsuccessful, to limit the number of location updating

attempts, an attempt counter need be used. The attempt counter is reset when MS is

switched on or a SIM card is inserted.

MS contains a list of "forbidden location areas for roaming", as well as a list of

"forbidden location areas for regional provision of service". These lists shall be erased

when an MS is switched off or when SIM is removed. Whenever a LOCATION

UPDATING REJECT message is received with the cause "Roaming not allowed in

this location area" or with the cause "Location area not allowed", the LAI received on

BCCH that triggered the location updating request shall be added to the relevant list.

The two lists shall accommodate 10 or more entries. When the list is full and a new

entry has to be inserted, the oldest entry shall be deleted.

Upon successful location updating, MS sets the update status to "UPDATED" in SIM

(UPDATED status indicates the last location updating request is successful) , and

save LAI, TMSI, Cipher Key and Cipher Sequence Number in SIM, and stores the

received new location area information in SIM.




4-2

4.2 Location Updating Procedure

The normal location updating procedure, periodic location updating procedure and

IMSI attach procedure are basically the same (The difference are described in detailsin relevant subsections below). See Figure 4-1 for the location updating procedure.

BTS BSC MSCMS

Channel ACT

Channel ACT ACK

I MM ASS CMD

Channel REQ

CC

TMSI Reallocation CMP

Location Updating Accept

(1)

(3)

(4)

(5)

SABM

EST IND( LOC UPD REQ) CR(CMP L3 information)

UA

(6)

(7)

(8) (9)

(10)

(11)

(13)

Channel RQD (2)

Clear Command (14)

Clear Complete (15)

Location U pdating Reject (12)

Figure 4-1 Location updating procedure

1) MS sends a CHANNEL REQUEST message to BTS on the access channel of

Um interface (The message contains the access cause value "Location update").

2) BTS sends a CHANNEL REQUEST message to BSC.

3) Upon receipt of the CHANNEL REQUEST message, BSC allocates signaling

channels, and sends a CHANNEL ACTIVATION message to BTS.

4) If the channel type is correct, upon receipt of the CHANNEL ACTIVATION

message, BTS opens the power amplifier on the specified channel, and sends a

CHANNEL ACTIVATION ACKNOWLEDGE message to BSC.

5) BSC sends an IMMEDIATE ASSIGNMENT COMMAND message to MS via

BTS.

6) MS sends an SABM frame for establishing link with BTS

7) BTS returns a UA frame for acknowledgement.

8) BTS sends an ESTABLISHMENT INDICATION message to BSC, which contains

the content of the LOCATION UPDATE REQUEST message.

9) BSC establishes SCCP link connection on A interface, and sends a LOCATION

UPDATE REQUEST message to MSC. The parameter including the CGI of the

current cell.

10) MSC returns a link acknowledge message to BSC.




4-3

11) MSC sends a LOCATION UPDATING ACCEPT message to BSC, indicating that

location updating has succeeded.

12) The network shall deliver a LOCATION UPDATING REJECT message to MS if it

rejects the location updating request.13) If "Allocate TMSI upon location updating" is set to "No" in MSC, MS shall not

report the TMSI REALLOCATION COMPLETE message in the location updating

procedure.

14) The network shall initiate the channel release procedure if no further transactions

are scheduled.

4.2.1 Periodic Updating

Periodic updating is used to notify periodically the availability of MS to the network. It

is performed by using the location updating procedure. The location updating typeinformation element in the LOCATION UPDATING REQUEST message shall indicate

periodic updating.

The procedure is controlled by timer T3212 in MS. If the timer has not been started,

the timer shall be started each time MS enters the "NORMAL SERVICE" or

"ATTEMPTING TO UPDATE" sub-state of the "MM IDLE" state. When MS leaves the

"MM Idle" state (MM IDLE state indicates MS in inactivation state, namely, it doesn't

process any call procedure, only in interception state. For example, in MOC or MOT

procedure, MS will leave MM_IDLE state), timer T3212 shall continue running until it

is overtime.

In the following cases, the timer shall be stopped (MS shall set the timer to its initial

value for the next location update).

z A LOCATION UPDATING ACCEPT or LOCATION UPDATING REJECT

message is received.

z An AUTHENTICATION REJECT message is received.

z The first MM message (Such as LOCATION ACCEPT, CM SERVICE ACCEPT

etc.) is received, or ciphering mode setting is completed in the case of MM

connection establishment, except when the most recent service state is

"LIMITED SERVICE".

z MS has responded to paging and thereafter has received the first correct layer 3

message except RR message.

z Timer T3212 expires.

z MS is deactivated (i.e. MS switched off or SIM removed).

When timer T3212 expires, the location updating procedure shall be started.

When MS is in the service state of "NO CELL AVAILABLE", "LIMITED SERVICE",

"PLMN SEARCH" or "PLMN SEARCH-NORMAL SERVICE", if the T3212 timer

expires, the location updating procedure shall be delayed until the MS leaves this

service state. The (periodic) location updating procedure is not be started if the




4-4

system information at the time the T3212 timer expires indicates that periodic location

update shall not be used. The timeout value is contained in control channel

description IE of the SYSTEM INFORMATION TYPE 3 message.

The T3212 timeout value shall not be changed when MS is in the state of "NO CELL

AVAILABLE", "LIMITED SERVICE", "PLMN SEARCH or PLMN SEARCH-NORMAL"

etc.

When a change of the T3212 timeout value has to be taken into account and the

timer is running (at change of the serving cell or, the broadcast of T3212 timeout

value), MS shall take the mod that the current T3212 value to the new T3212 timeout

value as the new initial value.

When MS is activated, or when a change of the T3212 timeout value has to be taken

into account and the timer is not running, the new timer shall be started at a valuerandomly, uniformly drawn between 1 and the new initial value.

4.2.2 IMSI Attach Procedure

The IMSI attach procedure is the complement of the IMSI detach procedure. It is used

to indicate the IMSI as active in the network. There is a flag (ATT) in the SYSTEM

INFORMATION TYPE 3 message, which indicates whether the attach and detach

procedures are required to be used or not.

The IMSI attach procedure is invoked when the IMSI is activated by MS, if thedetach/attach procedures are required by the network.

When IMSI is activated by MS within the network coverage area, or if MS is moved

from outside the coverage area to the coverage area. The IMSI attach procedure is

used only if the update status is "UPDATED" and if the stored LAI is the same as the

one which is actually broadcasted on the BCCH of the current serving cell. Otherwise

a normal location updating procedure shall be invoked, which is independent of the

ATT flag indication.

IMSI attach is performed by using the location updating procedure. The location

updating type information element in the LOCATION UPDATING REQUEST message

must in this case indicate IMSI attach.

4.2.3 Generic Location Updating Procedure

Any timer used for triggering the location updating procedure (e.g. T3211 and T3212)

is stopped if running.

As no RR connection exists at the time when the location updating procedure has to

be started, the MM sublayer within MS will request the RR sublayer to establish a RR




4-5

connection and enter the state of "WAIT FOR RR CONNECTION (LOCATION

UPDATE)".

MS initiates the location updating procedure by sending a LOCATION UPDATING

REQUEST message to the network, starts the timer T3210 and enters the state of

"LOCATION UPDATING INITIATED". The location updating type information element

shall indicate what kind of updating is requested.

I. Network requests for additional MS capability information

The network may initiate the classmark interrogation procedure, for example, to

obtain further information on MS's encryption capabilities.

II. Identification request

The network may initiate the identification procedure, e.g. if the network is unable to

get the IMSI based on the TMSI and LAI used as identification by MS

III. Authentication procedure

The authentication procedure may be initiated by the network upon receipt of the

LOCATION UPDATING REQUEST message from MS.

IV. Ciphering mode setting procedure

The ciphering mode setting procedure may be initiated by the network, if a new TMSI

has to be allocated.

V. Attempt counter

When location updating is unsuccessful, to limit the number of location updating

attempts, an attempt counter is used. It counts the number of consecutive

unsuccessful location update attempts.

The attempt counter is incremented by 1 each time a location update procedure fails.

In the following cases, the attempt counter shall be reset.

z MS is powered on

z A SIM card is inserted

z Location update is successfully completed

z Location update is completed with cause 11/12/13

z Service state changes from "ATTEMPTING" into "UPDATE"

z A new location area is entered

z Timer T3212 expires

z Location update is triggered by a CM sublayer request




4-6

The attempt counter is used when MS decides whether to re-attempt a location

update after timeout of timer T3211.

VI. Location updating accepted

If the location updating is accepted by the network, a LOCATION UPDATING

ACCEPT message shall be transferred to MS.

In case the identity confidentiality service is active, the TMSI reallocation may be part

of the location updating procedure. The TMSI allocated is then contained in the

LOCATION UPDATING ACCEPT message together with LAI. The network shall in

this case start the supervision timer T3250.

Upon receipt of a LOCATION UPDATING ACCEPT message, MS stores the received

LAI, stops timer T3210, resets the attempt counter and sets the update status in SIMto "UPDATED". If the message contains an IMSI, MS is not allocated any TMSI, and

shall delete any TMSI from SIM accordingly. If the message contains a TMSI, the MS

is allocated this TMSI, and shall store this TMSI in SIM and send a TMSI

REALLOCATION COMPLETE to the network. If neither IMSI nor TMSI is received in

the LOCATION UPDATING ACCEPT message, the old TMSI if any available shall be

kept.

If the LAI or PLMN identity contained in the LOCATION UPDATING ACCEPT

message is a member of any of the "forbidden lists", the relevant entries shall be

deleted.

VII. Location updating rejected

If the location updating cannot be accepted, the network sends a LOCATION

UPDATING REJECT message to the MS. After receipt of the LOCATION UPDATING

REJECT message, MS shall stop timer T3210, store the reject cause, start T3240,

enter the state of "LOCATION UPDATING REJECTED" and await the release of the

RR connection triggered by the network. Upon the release of the RR connection, MS

shall take the following actions depending on the stored reject cause.

z Cause 2: IMSI unknown in HLRz Cause 3: illegal MS

z Cause 6: illegal ME

For cause 2/3/6, the MS shall set the update status to "ROAMING NOT ALLOWED",

and delete any TMSI, stored LAI and ciphering key sequence number and shall

consider IMSI invalid until switch-off.

z Cause 11: PLMN not allowed

z Cause 12: location area not allowed

z Cause 13: roaming not allowed in this location area




4-7

For cause 11/12/13, MS shall delete any LAI, TMSI and ciphering key sequence

number stored in from SIM, reset the attempt counter, and set the update status to

"ROAMING NOT ALLOWED". MS shall store the LAI or the PLMN identity in the

relevant forbidden list, i.e. in the "forbidden PLMN list" for cause 11, in the list of "forbidden location areas for regional provision of service" for cause 12, and in the list

of "forbidden location areas for roaming" for cause 13. In addition, MS will memorize if

cause 13 is received, so to perform PLMN selection instead of cell selection when it is

back to the "MM IDLE" state.

Other cause values are considered as abnormal cases.

VIII. Release of RR connection after location updating

When the location updating procedure is completed, MS shall (except in the case that

MS has a follow-on CM application request pending and has received the follow-on

proceed indication) set timer T3240 and enter the state of "WAIT FOR NETWORK

COMMAND", expecting the release of RR connection. The network may decide to

keep the RR connection for network-initiated establishment of a new MM connection,

or to allow for MS-initiated MM connection establishment.

Any release of RR connection shall be initiated by the network. If the RR connection

is not released within a given time controlled by timer T3240, MS shall abort the RR

connection. In both cases, either after a RR connection release triggered from the

network side or after a RR connection abort requested by MS side, MS shall return to

the state of "MM IDLE".

At transition to the state "MM IDLE", sub-state "NORMAL SERVICE" or

"ATTEMPTING TO UPDATE", either timer T3212 or timer T3211 is started.

IX. Abnormal cases on MS side

There are the following abnormal cases on MS side.

1) Access barred because of access class control

MS stays in the current serving cell and initiates the normal cell reselection procedure.

The procedure is started as soon as the access is allowed.

2) The answer to random access is an IMMEDIATE ASSIGNMENT REJECT

message

MS stays in the chosen cell and applies the normal cell selection procedure. Timer

T3122 is reset when a cell change occurs. The procedure is started as soon as timer

T3122 expires.

3) Random access failure




4-8

If random access failure occur, Timer T3213 is started. When it expires, the random

access procedure is attempted again. The location updating procedure is aborted if

random access fails twice successively.

4) RR connection failure

The procedure is aborted.

5) T3210 timeout

The procedure is aborted, and the RR connection is terminated.

6) RR released before the normal end of procedure

The procedure is aborted.

7) Location updating rejected, due to cause except 2/3/6/11/12/13

MS waits for release of the RR connection. In cases 4~7 and for repeated failures as

defined in case 3, MS proceeds as follows. Timer T3210 is stopped if still running.

The RR connection is released if timer T3210 expires. The attempt counter is

incremented by 1. The next actions depend on LAI and the value of the attempt

counter.

Case 1: The update status is "UPDATED", and the stored LAI is equal to the one

received on the BCCH from the current serving cell. The attempt counter is smaller

than 4.

In case 1, MS shall keep the update status to "UPDATED". The MM IDLE sub-state

after RR connection release is "NORMAL SERVICE". MS shall memorize the locationupdating type used in the location updating procedure. It shall start timer T3211 when

the RR connection is released. When timer T3211 expires, the location updating

procedure is triggered again with the memorized location updating type.

Case 2: Either the update status is different from "UPDATED", or the stored LAI is

different from the one received on the BCCH from the current serving cell, or the

attempt counter is greater or equal to 4.

In case 2, MS shall delete any LAI, TMSI and ciphering key sequence number stored

in SIM, set the update status to "NOT UPDATED" and enter the MM IDLE sub-state

"ATTEMPTING TO UPDATE" when the RR connection is released. If the attempt

counter is smaller than 4, MS shall start timer T3211. Otherwise, it starts timer T3212.

X. Abnormal cases on network side

1) RR connection failure

If a RR connection failure occurs during a common procedure which is integrated with

the location updating procedure, the behavior of the network should be according to

the description of that common procedure.




4-9

If there is no other common procedure integrated, the location updating procedure

towards MS shall be aborted.

2) Protocol error

If the LOCATION UPDATING REQUEST message is received with a protocol error,

the network shall, if possible, return a LOCATION UPDATING REJECT message with

one of the following causes.

z Cause 96: Mandatory IE error

z Cause 99: IE non-existent or not implemented

z Cause 100: Conditional IE error

z Cause 111: Protocol error, unspecified

After sending the response message, the network will start the channel release

procedure.


The location updating procedure is a general procedure for three purposes: normal

location updating, periodic updating and IMSI attach.

The BSC retrieves the periodic location updating period from the “T3212” field in the

[System information table] and sends it to the MS through the SYSTEM

INFORMATION TYPE 3 message.

The BSC sends a LOCATION UPDATING REQUEST message to the MSC to set upan SCCP connection over interface A. This message includes the CGI of the serving

cell. See [BSC Cell Table] for the CGI.



Signaling Analysis ManualM900/M1800 Base Station Subsystem Chapter 5 Authentication Procedure

5-1

Chapter 5 Authentication Procedure

5.1 Overview

Authentication refers to the procedure of authenticating the validity of the IMSI and

TMSI of MS initiated by the GSM network.

The purpose of the authentication procedure is to prevent illegal MS from accessing

the network, and in the meantime, to protect the private information of legal MS from

leakage.

On the following conditions, the network may initiate the authentication procedure.

z MS requests modification of its relevant information in VLR or HLR.

z Service access is initiated (MS originates a call. MS is called. MS is

activated/deactivated. Supplementary service is initiated)

z MS accesses the network for the first time after MSC/VLR is restarted

z The ciphering key sequence number Kc is not matched.

The purpose of the authentication procedure is twofold.

z To permit the network to check whether the identity provided by MS is

acceptable or not

z To provide parameters enabling MS to calculate a new ciphering key

The authentication procedure is always initiated and controlled by the network.

5.2 Authentication Procedure

The network initiates the authentication procedure by transferring an

AUTHENTICATION REQUEST message to MS and starts timer T3260. The

AUTHENTICATION REQUEST message contains the parameters used to calculate

the response parameters, and also contains the CKSN (Ciphering Key SequenceNumber) allocated to the key which may be computed from the given parameters.

Upon receipt of the AUTHENTICATION REQUEST message, MS processes the

challenge information and sends back an AUTHENTICATION RESPONSE message

to the network. The new ciphering key Kc calculated from the challenge information

shall overwrite the previous one and be stored in SIM before the AUTHENTICATION

RESPONSE message is transmitted. The CKSN shall be stored together with the

calculated Kc.

Upon receipt of the AUTHENTICATION RESPONSE message, the network stops

timer T3260 and checks the validity of the response.




5-2

5.2.1 Successful Authentication

Figure 5-1 shows the procedure of successful authentication.

AUT_REQ(1)

AUT_RES(2)

MSCBSCBTSMS

Figure 5-1 Procedure of successful authentication

1) The AUTHENTICATION REQUEST message contains a RAND (Random

Number) and a CKSN. There are total 128 bits in the RAND.

2) The AUTHENTICATION RESPONSE message contains a response number

(SRES), which is obtained based on calculation of RAND and Ki through the A3

algorithm.

The network compares the SRES stored in itself with the one contained in the

AUTHENTICATION RESPONSE message. If the two are consistent, authentication

shall be passed, and the subsequent sub-procedures (such as the encryptionprocedure) shall be entered.

5.2.2 Unsuccessful Authentication

If authentication fails, i.e. if the response is not valid, the network may distinguish

between the two different modes of identification adopted by MS:

1) If TMSI identification mode has been adopted, the network shall initiate the

identification procedure. If the IMSI given by MS differs from the one the network

has associated with the TMSI, the network shall restart the authenticationprocedure. If the IMSI provided by MS is correct, the network shall return an

AUTHENTICATION REJECT message.

2) If IMSI identification mode has been adopted, the network shall directly return an

AUTHENTICATION REJECT message. Figure 5-2 shows the

AUTHENTICATION REJECTion procedure.




5-3

MSC

AUT_RES(2)

AUT_REJ(3)

BSCBTSMS

AUT_REQ(1)

Figure 5-2 AUTHENTICATION REJECTion procedure

After the network sends the AUTHENTICATION REJECT message, all MM

connections in progress are released, and the network restarts the RR connection

release procedure.

Upon receipt of the AUTHENTICATION REJECT message, MS sets the update status

in SIM to "U2 ROAMING NOT ALLOWED", deletes from SIM the stored TMSI, LAI

and CKSN.

If the AUTHENTICATION REJECT message is received in the state "IMSI DETACH

INITIATED", timer T3220 shall be stopped when the RR connection is released. If

possible, MS should initiate the local release procedure after the normal release

procedure is completed, or after T3220 expires. If this is not possible (e.g. detach at

power-off), the MSRR sublayer shall be aborted.

If the AUTHENTICATION REJECT message is received in any other state, MS shall

abort any MM connection establishment or call re-establishment procedure, stop any

of the timers T3210 or T3230 (if running), release all MM connections, reset and start

timer T3240, and enter the state "WAIT FOR NETWORK COMMAND", expecting the

release of the RR connection. If the RR connection is not released within a given time

controlled by the timer T3240, MS shall abort the RR connection. In both cases, either

after a RR connection release triggered from the network side or after a RR

connection abort requested by the MS side, MS shall enter the substate "NO IMSI" of

"MM IDLE".


The network initiates and controls the authentication procedure. No special

processing is required from the BSC.




5-4

5.4 Abnormal Cases

5.4.1 RR Connection Failure

Upon detection of a RR connection failure before the AUTHENTICATION

RESPONSE message is received, the network shall release all MM connections (if

any) and abort any ongoing MM-specific procedure.

5.4.2 Expiry of Timer T3260

Before receipt of the AUTHENTICATION RESPONSE message, if timer T3260

expires, the network shall release the RR connection, abort the authentication

procedure and any ongoing MM-specific procedure, release all MM connections, andinitiate the RR connection release procedure.

5.4.3 SIM Unregistered

If the SIM of an MS has not been registered on the network side, the network will

directly return an AUTHENTICATION REJECT message to the MS.



Signaling Analysis ManualM900/M1800 Base Station Subsystem Chapter 6 Release Procedure

6-1

Chapter 6 Release Procedure

6.1 Overview

Common release procedure is classified into normal release procedure and local

release procedure. Normal release means that the release procedure is initiated by

MS or MSC. Local release means that the release procedure is initiated by BSC.

6.2 Normal Release Procedure

I. Signalling procedure

After being normally accessed to the network, MS can initiate the release procedure,

for the purpose of service requirements, such as hangup. Figure 6-1 shows the

release procedure.

DISC

REL

REL CMP

Clear CMD

Clear CMPChannel REL

REL IND

Deactive SACCH

RF Channel REL

RF Channel REL ACK

DISC

UA

RLSD

RLSD CMP

(1)

(2)

(3)

(4)

(5)

(6)

(7)

(8)

(9)

(10)

(11)

(12)

(13)

(14)

BTS BSC MSCMS

Figure 6-1 Release procedure initiated by MS

1) After a call is completed, the caller hangs up, and the calling MS sends a

DISCONNECT message to MSC.

2) MSC returns a RELEASE message to MS. In the meantime, it sends a

DISCONNECT message to another calling MS.




6-2

3) MS releases MM connections, and sends a RELEASE COMPLETE message to

MSC.

4) Upon receipt of the RELEASE COMPLETE message, MSC releases MM

connections, and sends a CLEAR COMMAND to BSC, notifying it to release theoccupied A interface resources and the logical channels on Um interface.

5) BSC delivers the channel RELEASE message to MS, requesting that MS and

BTS release the logical channels on Um interface.

6) MS sends a DISC frame to BTS, indicating that the logical channels have been

released.

7) BTS sends a UA frame to MS for acknowledgement. Upon receipt of the UA

frame, MS returns to the idle mode.

8) BSC sends a DEACTIVATE SACCH message to BTS, requesting that SACCH

be deactivated.

9) After BTS receives the DISC frame from MS, BTS returns a RELEASE

INDICATION message to BSC to indicate that MS has released the logic

channel on radio interface.

10) BSC sends a RF CHANNEL RELEASE message to BTS, requesting that the

physical channels on Um interface be released.

11) BTS returns a CHANNEL RELEASE ACKNOWLEDGE message to BSC,

indicating that the physical channels on Um interface have been released.

12) BSC sends a CLEAR COMPLETE message to MSC.

13) MSC sends a RLSD message to BSC, requesting the release of SCCP link

connection.

14) BSC returns a RLSD COMPLETE message to MSC, indicating that the SCCP

link connection has been released.

II. Procedure explanation

1) In Figure 6-1, 1~3 are to release call connections.

Note:

The procedure described in Figure 5-1 is a release procedure initiated by MS. For the release procedure

initiated by the network, except these 3 messages, which are transparently transmitted in reverse

directions, all the messages are the same as those in Figure 6-1.

2) 4~14 are to release radio resources.

After the connections of CC layer and MM layer are released, the network will send a

CLEAR COMMAND message to BSC, requesting the release of SCCP signalling

links. This message contains the call clearance cause values, such as "Handover

completed" or "Location update completed". If the release is caused by Um interface

message failure, radio link failure or equipment fault, BSC shall send the CLEAR




6-3

REQUEST message to MSC, and then MSC shall deliver the CLEAR COMMAND

message.

6.3 BSC Local Release Procedure

In the normal calling procedure, after assignment is completed, BSC shall initiate the

local release procedure for signalling channels. Likewise, after handover is completed,

BSC shall also initiate the local release procedure for the old channels. Figure 6-2

shows the release procedure.

BTS BSC MSCMS

REL Confirrm

Deactivate SACCH

RF Channel REL

RF Channel REL ACK

(1)

(3)

(4)

(5)

REL REQ(REL Local End) (2)

Figure 6-2 BSC local release procedure

1) BSC sends a DEACTIVATE SACCH message to BTS, requesting that SACCHto be deactivated.

2) BSC delivers a RELEASE REQUEST message to BTS, with the cause value

"Local end released". Here, the release procedure is irrelated to MS.

3) Upon receipt of the RELEASE REQUEST message, BTS returns a RELEASE

ACKNOWLEDGE message to BSC. If the RELEASE REQUEST message

delivered by BSC contains other cause values, BTS should deliver a DISC frame

to MS, and shall not report the RELEASE ACKNOWLEDGE message to BSC

until it receives the UA (or DM) frame sent by MS.


Refer to 6.2 Normal Release Procedure.



Signaling Analysis ManualM900/M1800 Base Station Subsystem

Chapter 7Mobile Originating Call Establishment Procedure

7-1

Chapter 7 Mobile Originating Call Establishment

Procedure

7.1 Overview

Mobile originating call services include (not including mobile-originated SMS)

z MS calls MS

z MS calls fixed telephone

7.2 Normal Procedure

As per assignment type, the mobile originating call establishment procedure can be

classified into 3 types, early assignment, late assignment and very early assignment.

The selection of early assignment and late assignment is determined by MSC. The

selection of very early assignment is determined by BSS as per the status of radio

resources.

7.2.1 Mobile Originating Call Establishment without OACSU (Early

Assignment)

Note:

OACSU denotes "Off-Air-Call-Set-Up".





7-2

I. Signaling procedure

Channel ACT (3)

Channel ACT ACK (4)

IMM ASS CMD (5)

BTS BSC MSCMS

Channel REQ (1)

SABM (6)

EST IND (CM Service REQ) (8)CR (CMP L3 information) (9)

CC (10)

Setup (12)

Call Proceeding (13)

ASS REQ (14)

ASS CMD (17)

SABM (18)

EST IND (20)

ASS CMP (21) ASS CMP (22)

Alerting (23)

Connect (24)

Connect ACK (25)

Talking (26)

DISC (27)

REL

REL CMP

Clear CMD (30)

Clear CMP (38)

CM Service Accepted (11)

Channel ACT (15)

Channel ACT ACK (16)

UA (19)

UA (7)

Channel REL (31)

REL IND (35)

Deactive SACCH (34)

RF Channel REL (36)

RF Channel REL ACK (37)

DISC (32)

UA (33)

RLSD (39)

RLSD CMP (40)

(28)

(29)

Channel RQD (2)

Figure 7-1 Mobile originating call establishment without OACSU (early assignment)

1) MS sends a CHANNEL REQUEST message to BTS on the access channel

(RACH) of Um interface. The message contains the cause value "MOC", but that





7-3

value is not completely accurate, because it is indicated both in the mobile

originating call establishment procedure and IMSI detach procedure.

2) BTS sends a CHANNEL REQUIRED message to BSC.

3) Upon receipt of the CHANNEL REQUIRED message, BSC allocates a signalingchannel and sends a CHANNEL ACTIVATION message to BTS.


message, BTS opens the power amplifier on the specified channel, and sends a

CHANNEL ACTIVATION ACKNOWLEDGE message to BSC.

5) BSC sends an IMMEDIATE ASSIGNMENT COMMAND message to MS via BTS.

The message is sent on AGCH on Um interface.

6) MS sends an SABM frame on SDCCH to BTS to access the network.

7) BTS returns a UA frame on SDCCH for acknowledgement.

8) BTS sends an ESTABLISHMENT INDICATION message to BSC (This message

contains the accurate causes for MS's access. For example, different cause

values are indicated in the mobile originating call establishment procedure and

IMSI detach procedure). This message contains the contents of the CM

SERVICE REQUEST message.

9) BSC establishes the SCCP link connection on A interface, and sends a CM

SERVICE REQUEST message to MSC.

10) MSC returns a message to BSC to acknowledge the link connection.

11) MSC sends a CM SERVICE ACCEPTED message to MS. The message is sent

on SDCCH on Um interface.

12) The calling MS sends a SETUP message on SDCCH.

13) MSC sends a CALL PROCEEDING message to the calling MS. The message is

sent on SDCCH on Um interface.

14) MSC sends an ASSIGNMENT REQUEST message to BSC, which contains the

CIC allocated to A interface.

15) BSC allocates a TCH, and sends a CHANNEL ACTIVATION message to BTS.


message, BTS opens the power amplifier on the specified channel, starts to

receive the uplink information and sends a CHANNEL ACTIVATION

ACKNOWLEDGE message to BSC.

17) BSC sends an ASSIGNMENT COMMAND message to MS via BTS on SDCCH.

18) MS sends an SABM frame to BTS, to access the network on FACCH indicated in

the ASSIGNMENT COMMAND message.

19) BTS sends a UA frame for acknowledgement on FACCH.

20) BTS sends an ESTABLISHMENT INDICATION message to BSC.

21) After accessing the TCH, MS sends an ASSIGNMENT COMPLETE message to

BSC on FACCH.

22) After the radio traffic channel and terrestrial circuit are both successfully

connected, BSC sends an ASSIGNMENT COMPLETE message to MSC, and

regards this call in session state.





7-4

23) MSC sends an ALTERING message to the calling MS. The calling MS will hear

the ringback. The message is sent on FACCH on Um interface.

24) MSC sends a CONNECT message to MS. The message is sent on FACCH on

Um interface.25) The calling MS returns a CONNECT ACKNOWLEDGE message on FACCH to

MSC.

26) The calling MS and called MS enters the session state.

27) After the conversation is over, the calling MS hangs up and sends a

DISCONNECT message on FACCH.

28) MSC sends a RELEASE message to MS. The message is sent on FACCH on

Um interface.

29) MS returns a RELEASE COMPLETE message. The message is sent on FACCH

on Um interface.

30) MSC sends a CLEAR COMMAND message to BSC. Upon receipt of the

message, BSC initiates the release procedure. See Chapter 5 for the description

of the subsequent release procedure.

31) BSC sends a CHANNEL RELEASE message to MS through BTS, The message

is sent on FACCH on Um interface.

32) MS sends DISC frame on FACCH.

33) BTS returns UA frame on FACCH.


1) In Figure 7-1, 1~8 refer to the random access procedure and immediateassignment procedure. In the two procedures, BSS allocates signaling channels

to MS.

2) Between 10~11, there may exist an authentication procedure, ciphering mode

setting procedure and classmark interrogation procedure (updating procedure).

3) As per different data configuration of MSC, after the link connection is

established on A interface, MSC may not immediately deliver the CM SERVICE

ACCEPTED message. Instead, it may proceed as follows.

4) Initiate the ciphering mode setting procedure by delivering a Cipher Mode

Command (In that case, MSC shall not deliver the CM Service Accepted

message again).

5) Initiate the authentication procedure by delivering an AUTHENTICATION

REQUEST message.

6) Initiate the classmark updating procedure by delivering a CLASSMARK UPDATE

message.

7) In addition, if [ECSC] in BSC data configuration is set to "Yes", the dual-band MS

shall report a CLASSMARK CHANGE message after it reports an

ESTABLISHMENT INDICATION message.

8) 14~22 refer to the TCH assignment procedure.





7-5

In this procedure, BSS allocates the resources such as TCHs, A interface circuit, etc.

to MS.

9) 30~40 refer to the release procedure.

The procedure shown in Figure 7-1 is a release procedure in which the calling MS

first hangs up. The logical channels on Um interface are released prior to the physical

channels.





7-6

7.2.2 Mobile Originating Call Establishment with OACSU (Late Assignment)


Channel ACT

Channel ACT ACK

IMM ASS CMD

BTS BSC MSCMS

Channel REQ

SABM

EST IND( CM Service REQ)CR(CMP L3 information)

CC

Setup

Call Proceeding

ASS REQ

ASS CMD

SABM(18)

EST IND

ASS CMP ASS CMP

Alerting

Connect

Connect ACK

Talking (25)

DISC

REL

REL CMP

Clear CMD

Clear CMP

CM Service Accepted

Channel ACT (15)


UA

UA

Channel REL

REL IND

Deactive SACCH

RF Channel REL

RF Channel REL ACK

DISC

UARLSD

RLSD CMP

(1)

(2)

(3)

(4)

(5)

(6)(7)

(8)

(9)

(10)

(11)

(12)

(13)

(14)

(17)

(19)(20)

(21)(22)

(23)

(24)

(26)

(27)

(28)

(29)

(30)

(31)

(32)(33)

(34)

(35)

(36)

(37)

(38)

(39)

Figure 7-2 Mobile originating call establishment with OACSU (late assignment)

1) The difference between Figure 7-1 and Figure 7-2 is that late assignment takes

place after the Alerting indication is sent.





7-7

2) The advantage of late assignment lies in that it can save the seizure time of

TCHs.

3) The disadvantage of late assignment is that if the subsequent assignment is

unsuccessful, the called MS can only hear the ring but cannot establish aconnection, thus leading to user complaints. Therefore, in actual application, this

procedure is generally not adopted. Instead, the procedure in Figure 7-1 is

adopted.


For relevant explanation, please refer to 7.2.1 Mobile Originating Call Establishment

without OACSU (Early Assignment). The procedure in Figure 7-2 is a procedure in

which the calling MS first hangs up.





7-8

7.2.3 Mobile Originating Call Establishment with OACSU (Very Early

Assignment)


Channel ACT

Channel ACT ACK

IMM ASS CMD

BTS BSC MSCMS

Channel RQD

SABM


CC

Setup

Call Proceeding

ASS REQ

ASS CMP

Alerting

Connect

Connect ACK

Talking (23)

DISC

REL

REL CMP

Clear CMD

Clear CMP

CM Service Accepted

Mode Modify (16)

Mode Modify ACK (17)

UA

Channel REL

REL IND

Deactive SACCH

RF Channel REL

RF Channel REL ACK

DISC

UA

RLSD

RLSD CMP

(1)

(3)

(4)

(5)

(6)

(7)(8)

(9)

(10)

(11)

(12)

(13)

(14)

(15)

(20)

(21)

(22)

(24)

(25)

(26)

(27)

(28)

(29)

(30)(31)

(32)

(33)

(34)

(35)

(36)

(37)

Channel Mode Modify (18)

Channel Mode Modify ACK (19)

Channel REQ

(2)

Figure 7-3 Mobile originating call establishment with OACSU (very early assignment)

1) The difference between Figure 7-1 and Figure 7-3 is that the TCH allocated

during the immediate assignment in Figure 7-3 serves as a signaling channel.

Therefore, no TCH need be reallocated during the assignment procedure.





7-9

Instead, the TCH allocated in the immediate assignment procedure is adjusted

as a TCH by using the MODE MODIFY message.

2) Very early assignment generally takes place if there is no free SDCCH for

allocation during immediate assignment, but there are free TCHs and immediateassignment of TCHs is allowed in BSC data configuration.


For relevant explanation, refer to 7.2.1 Mobile Originating Call Establishment

without OACSU (Early Assignment). The procedure in Figure 7-3 is a procedure in

which the calling MS first hangs up.



1) Upon receipt of the CHANNEL REQUIRED message from the BTS, the BSC

allocates a signaling channel based on the channel type and channel allocation

algorithm required by the [Radio channel management control table], [HW II

Channel Allocation table] and the “TCH immediate assignment” field in the [Cell

call control table].

2) Upon receipt of the ESTABLISHMENT INDICATION message in the random

access procedure, the BSC adds the CGI of the current cell to the CM SERVICE

REQUEST message based on the [BSC Cell Table] and sends the message to

the MSC.

3) Upon receipt of the ASSIGNMENT REQUEST message from the MSC, the BSC

checks the channel type. Then it checks whether the data service is supported

based on the “Data Service allowed” field in the [Cell Configuration Table]. It

returns an ASSIGNMENT FAILURE message if the data service is not

supported.

4) The BSC checks the [Trunk Circuit Table] based on the CIC in the ASSIGNMENT

REQUEST message for whether the CIC exists. Then it checks whether the

circuit pool, the channel type in the ASSIGNMENT REQUEST message and the

supporting capability of the FTC board conflict. It returns an ASSIGNMENTFAILURE message to the MSC upon conflict.

5) Upon receipt of the ASSIGNMENT COMPLETE message from the MS, the BSC

fills in the ASSIGNMENT COMPLETE message over interface A interface based

on the “A-interface Phase flag” field in the [Local Office Information Table]. Then

it sends the message to the MSC.

7.4 Abnormal Cases

In the cases of loss of messages on Um interface, call interruption, hangup, abnormal

operation of transport/NSS/BSS equipment, the procedure may not be performed





7-10

normally. In addition, if MS resends multiple CHANNEL REQUEST messages during

an access attempt, BSS shall activate multiple signaling channels correspondingly.

Actually, MS shall only seize 1 signaling channel. Because no ESTABLISH

INDICATION message can be received from MS by other channels, other channelsshall be released upon timeout.

Because there are various causes for abnormal procedures, here, merely the

common cases are described.

7.4.1 Abnormal Random Access/Immediate Assignment Procedure

I. ESTABLISH INDICATION message cannot be received after a channel has

been activated

Generally, there are the following causes for this problem.

1) Due to defect design that does not comply with the protocols, MS resends

multiple CHANNEL REQUEST messages. As a result, BSS allocates and

activates too many signaling channels.

Even if BSS runs normally, during an access attempt, MS may resend multiple

CHANNEL REQUEST messages. As a result, BSS activates multiple signaling

channels. Actually, MS shall only seize 1 signaling channel. Because no

ESTABLISH INDICATION message can be received from MS by other channels,

other channels shall be released when the T3101 timer expires.2) On Um interface, uplink signals can be received normally, whereas, downlink

signals cannot be properly received by MS.

By tracing the Um interface on MS side, it may be found that MS cannot receive

the relevant information from BTS after it sends a CHANNEL REQUEST

message.

In that case, the user should check whether the uplink/downlink Rx level and Rx

quality are normal. If MS is not far from BTS, but the signals are of low Rx level

and poor Rx quality, the user should check whether the antenna & feeder of BTS,

the antenna of MS, battery, etc. work normally.

3) Tx-integer and CCCH are improperly configured in BSC data configuration.

The configuration mode of Tx-integer and CCCH has impact upon the

retransmission interval of MS's CHANNEL REQUEST message.

II. BSC sends an IMMEDIATE ASSIGNMENT REJECT message

If BSC sends an IMMEDIATE ASSIGNMENT REJECT message to MS upon receipt

of a CHANNEL REQUEST message, generally, the causes may be as follows.





7-11

1) BSC cannot find an appropriate signaling channel (Generally, the signaling

channel is SDCCH, but it can also be TCH) to allocate to the MS, generally,

because no signaling channel is available, e.g. all signaling channels are in busy

state or the channels have been blocked.2) BTS returns CHANNEL ACTIVATION NEGATIVE ACKNOWLEDGE messages to

BSC after it delivers a CHANNEL ACTIVATION message to MS.

If BTS returns many CHANNEL ACTIVATION NEGATIVE ACKNOWLEDGE

messages to BSC, the problem generally lies in that the unstable transmission on

Abis interface has lead to the inconsistency between the channel states of BSC and

BTS, or abnormality has occurred to a board in BTS.

7.4.2 MSC Directly Delivers DISCONNECT to Clear the Call, Instead of

Delivering the Assignment Request

In the MS call procedure, after the immediate assignment procedure is finished, the

following procedure is assignment. Sometimes MSC doesn't send ASSIGNMENT

REQUEST message, but send DISCONNECT message to MS, and then disconnect

the call. After this problem occurs, usually, a large quantity of MSs shall complain

that calls cannot be put through. In that case, the following points should mainly be

checked.

1) The state of A interface circuit on MSC side.

2) The consistency between A interface data of MSC and A interface data of BSC,

especially circuit pool data.

7.4.3 Abnormal Assignment Procedure

I. ASSIGNMENT FAILURE

Upon receipt of an ASSIGNMENT REQUEST message, BSC returns an

ASSIGNMENT FAILURE message, instead of an ASSIGNMENT COMPLETE

message. The common causes are as follows.

1) There is no appropriate TCH for allocation in BSC.There is no appropriate TCH for allocation in BSC, possibly because all TCHs are in

busy state or have been blocked.

The ASSIGNMENT FAILURE message returned by BSC contains the cause value

"No radio resource".

In that case, the user can solve the problem by BTS expansion (adding TRX),

modifying the access threshold and open the direct re-attempt permit switch.

2) MS fails to access the TCH, and sends an ASSIGNMENT FAILURE message on

the signaling channel.





7-12

Due to the particularity of the transmission on Um interface, this problem is actually

the most common problem in the network, and cannot be solved completely. If this

problem occurs frequently, it may lead to user complaints. The major points to be

checked are the antenna & feeder, the relevant boards in BTS, and access-relatedparameters in BSC data configuration.

3) On BSC side, A interface circuit is found abnormal, e.g. The CIC contained in the

ASSIGNMENT REQUEST message is not available.

In that case, the user should check the A interfaces.

4) Abnormality occurs to the relevant equipment in BSC.

The ASSIGNMENT FAILURE message returned by BSC generally contains the cause

value "Equipment failure".

In that case, the major points to be checked are as follows.z The boards and their respective backplanes and optical fiber that are related to

the inter-module communication in BSC, such as GMC2, GMCC, GSNT, GOPT

and GFBI.

z The boards related to A interface, such as E3Ms, TCSMs and their backplanes

5) Abnormality occurs to the transmission on interface A.

II. Directed Retry

Because there is no appropriate TCH for allocation, and the directed re-attempt

permit switch is set to "On" in BSC data configuration, upon receipt of an ASSIGNMENT REQUEST message from MSC, BSC shall initiate a directed retry

handover procedure as per the actual situation, so that MS can directly attempt to

access other cells.

7.4.4 Abnormal Procedure Cause by Call Interruption

Call interruption might occur in any procedure to the calling/called MS, and as a result,

the subsequent procedures cannot be completed normally. For example, after BSC

receives an ASSIGNMENT REQUEST message from MSC, call interruption occurs to

MS on signaling channel. In that case, the assignment procedure probably is not be

finished (For example, the channel is just assigned and the Assignment Command is

not sent) BSC probably shall not return an ASSIGNMENT COMPLETE or

ASSIGNMENT FAILURE message to MSC. Instead, it shall send a CLEAR

REQUEST message.

7.4.5 Abnormal Procedure Caused by Hangup

The calling/called MS may hang up in any procedure, and as a result, the subsequent

procedures cannot be completed normally. For example, after BSC receives an





7-13

ASSIGNMENT REQUEST message from MSC, MS suddenly hangs up. In that case,

the call establishment may be already terminated before BSC returns an

ASSIGNMENT COMPLETE or ASSIGNMENT FAILURE message to MSC. As a result,

the procedure is neither a successful assignment procedure (BSC sends an ASSIGNMENT COMPLETE message), nor an unsuccessful assignment procedure

(BSC sends an ASSIGNMENT FAILURE message).

7.4.6 Abnormal Procedure Caused by MSC Clearing

After the link connection on A interface is established, due to some causes, MSC may

send a CLEAR COMMAND or DISCONNECT message to BSC, and as a result, the

subsequent procedures cannot be completed normally. For example, after BSC

receives an ASSIGNMENT REQUEST message from MSC, MS suddenly hangs up.

In that case, the call establishment may be already terminated before BSC returns an

ASSIGNMENT COMPLETE or ASSIGNMENT FAILURE message to MSC. As a result,

the procedure is neither a successful assignment procedure (BSC sends an

ASSIGNMENT COMPLETE message), nor an assignment failure procedure (BSC

sends an ASSIGNMENT FAILURE message).

If this problem frequently occurs, the following points should be analyzed specially.

1) The cause value contained in the CLEAR COMMAND message

If a call terminates normally, the CLEAR COMMAND message generally contains the

cause value "Call control". Otherwise, it may contain the cause value of "ProtocolError", or "Equipment failure", etc.

2) The time difference between the previous message and the CLEAR COMMAND

or DISCONNECT message in the procedure

The user can analyze the time difference between the two successive messages, to

see whether there is possibility that the abnormal procedure has been triggered by

timeout.




Chapter 8Mobile Terminating Call Establishment Procedure

8-1

Chapter 8 Mobile Terminating Call Establishment

Procedure

8.1 Overview

Mobile terminating calls include the calls initiated by MS and those initiated by fixed

telephones.





8-2



Channel ACT (6)

Channel ACT ACK (7)

IMM ASS CMD (8)

BTS BSC MSCMS

Channel REQ (4)

SABM (9)

EST IND( Paging RESP) (11)CR(CMP L3 information) (12)

CC (13)

Setup (15)

Call Confirmmed (16)

ASS REQ (17)

ASS CMD

SABM (21)

EST IND

ASS CMP ASS CMP

Alerting

Connect

Connect ACK Talking

DISC

REL (30)

REL CMP

Clear CMD

Clear CMP

CM Service Accepted (14)

Channel ACT (18)


UA

UA (10)

Channel REL

REL IND

Deactive SACCH

RF Channel REL

RF Channel REL ACK

DISC

UARLSD

RLSD CMP

(20)

(22)(23)

(24)(25)

(26)

(27)

(28)

(29)

(31)

(32)

(33)

(34)

(35)(36)

(37)

(38)

(39)

(40)

(41)

(42)

paging (1)paging CMD (2)

paging REQ (3)

Channel RQD (5)

Figure 8-1 Normal procedure of mobile terminating call establishment

1) When the paged MS is located in the serving area of MSC, MSC sends a

PAGING message to BSC, which contains a paged cell list, TMSI and IMSI.

2) BSC sends a PAGING COMMAND message to the paged cells, which contains

the relevant paging subchannel Nos. and the occupied timeslot Nos.

3) Upon receipt of the PAGING COMMAND message from BSC, BTS sends a

PAGING REQUEST message on the paging subchannel (PCH subchannel) that





8-3

belongs to the paging group. This message contains the IMSI or TMSI of the

paged MS.

4) MS sends a CHANNEL REQUEST message on RACH if it finds itself paged

after decoding the paging message.5) For other messages, please refer to Chapter 7 Mobile Originating Call

Establishment Procedure.


1) Paging signaling procedure

In Figure 8-1, 1~11 refer to the paging signaling procedure, in which, BSS initiates

paging and allocates signaling channels to MS.

2) Classification of assignment procedure

As per assignment type, the assignment procedure can be classified into 3 types,early assignment, late assignment and very early assignment. Except the late

assignment procedure, in which, the ASSIGNMENT REQUEST message is delivered

after MSC has received a CONNECT message from MS, the other procedures are

basically the same as the mobile originating call establishment procedure. For details,

please refer to Chapter 7 Mobile Originating Call Establishment Procedure.



1) Upon receipt of the PAGING message over interface A, the BSC checks whether

to enable flow control based on the [Flow Control Parameter Table].

2) The BSC transfers the PAGING message to the relevant BM module after

checking the [Cell module information table].

3) The BM module computes a paging group and sends it out.

4) The BM module computes the paging group based on the TMSI or IMSI in the

PAGING message and on the following parameters in the [System information

table]: “BS_AG_BLKS_RES”, “CCCH-CONF” and “BS_PA_MFRMS”.

8.4 Abnormal Cases

This section only analyzes the common abnormal procedures. For the other abnormal

procedures, refer to Chapter 7 Mobile Originating Call Establishment Procedure.

Upon paging failure, the MSC prompts voice information to the calling party, indicating

that the called MS is outside the serving area or cannot be connected. In this case,

trace the signaling on interfaces A and Abis to check whether the paging failure is

caused by:

z no PAGING COMMAND on interface A

z no PAGING COMMAND on interface Abis





8-4

z no PAGING RESPONSE on interface Abis

z no PAGING RESPONSE on interface A

8.4.1 No PAGING COMMAND on Interface A

Through signaling tracing over interface A, the MSC is detected that it has not sent a

PAGING message to the BSC. In this case, check the data configuration and MS

information in the MSC/VLR and HLR on the NSS side. Additionally, power off the

called MS, power it on and make a test call to check whether the MS is normal.

I. Check user data in VLR

When an MS is paged, MSC judges the current state of the MS as per the user data

(including MS active state, registered LA, cell information, etc.), and thus decides

whether to send the PAGING message or how to send the PAGING message.

If the MS state has changed (e.g. the MS is switched off, or has entered a different

LA), but due to various reasons, the MS has not performed registration in the network

normally, and has not updated the user data in VLR, the MS may probably be unable

to be paged.

In that case, the MS is required to initiate a location updating procedure, so that the

user data in VLR can be ensured correct. The period of periodic location update is

indicated for MS by BSC in the system information. On MSC side, there is also a

location update period. Refer to Chapter 4 Location Update Procedure. The twoparameters of BSC and MSC must satisfy a certain relationship, which requires that

MS must initiate a location update procedure within the period specified in MSC.

Generally, the location update period configured in BSC is shorter than that in MSC.

II. Check RA- or cell-related parameter settings in MSC

If a routing area or cell related parameter is incorrectly set in the MSC, the

transmission of the PAGING message might fail. For example, if a wrong target BSC

is selected, the PAGING message that should have been sent to the local BSC will be

sent to another BSC.

8.4.2 No PAGING COMMAND on Interface Abis

Upon receipt of the PAGING message from the MSC, the BSC detects that the MSC

has not sent PAGING COMMAND to the BTS over interface Abis. In this case, check

the operations and data configuration in the BSC.





8-5

I. Check whether flow control is enabled

z Check whether the system load suddenly increases due to centralized

transmission of short messages or mass access bursts

Query the traffic statistics about “Number of immediate assignment requests” and

“Number of CS service paging requests” in the BSC overall performance

measurement. Compare the query results before and after the failure in paging the

called MS and check whether the flow control function is enabled.

z Check whether the flow control parameter is correctly set

II. Check relevant data configuration

z Check whether the CGI information in BSC data configuration is consistent with

the LAC information in the PAGING message over interface A

Log in to the BSC Data Management System. Click [BSC/Cell/Cell Module

Information Table] to check whether the parameters in the table are correctly set.

Additionally, if a RA- or cell-related parameter is not correctly set in the MSC, for

example, a wrong target BSC is selected, the PAGING COMMAND message cannot

be successfully sent over interface Abis.

z Check whether the settings for the BSC parameters that will affect paging groups

are correct

Check whether the following parameters in the [System information table] are

correctly set: “BS_AG_BLKS_RES”, “CCCH-CONF” and “BS_PA_MFRMS”.

III. Check inter-module communications in BSC

Because Huawei BSC adopts multi-module structure, upon receipt of a PAGING

message from MSC, BSC performs paging as per the LA cell information in the

PAGING message. In that case, the PAGING COMMAND message to be delivered to

BTS may be transferred between the modules in BSC. If an exception occurs to the

inter-module communications, no PAGING COMMAND message can be transferred

between the modules or sent o interface Abis.

Abnormal inter inter-module communications can be verified through relevant BSC

alarms.

8.4.3 No PAGING RESPONSE on Interface Abis

Through signaling tracing over interface Abis, the BSC is detected that it has not

received the Establishment Indication (PAGING RESPONSE) after sending PAGING

COMMAND to the BTS. In this case, check the relevant data configuration and radio

signal coverage.





8-6

I. PCH or AGCH overloaded due to centralized short message transmission or

mass access bursts

Query the traffic statistics about “Number of immediate assignment requests” and

“Number of CS service paging requests” in the cell overall performance measurement.

Compare the query results before and after the failure in paging the called MS and

check whether the PCH or AGCH is overloaded due to centralized short message

transmission or mass access bursts.

II. Check the called MS or SIM in it

If an MS of a certain model or lot cannot provide the required processing capability or

if the SIM card in the MS is unavailable, the sending of the PAGING message might

fail. In this case, perform the following:

z Insert a different (normal) SIM into the called MS to check whether the original

SIM in the MS is functional

z Insert the SIM in the called MS into an MS from a different manufacturer to check

whether the MS is normal

III. Check BTS by making test calls in a different cell

z Make a test call in a different cell under the same BTS

z Make a test call under a different BTS of the same type

z Make a test call under a BTS of a different type

z Make a test call under a BTS from a different manufacturer

IV. Check data configuration in BSC

z Check the settings for the parameters that will affect paging groups

Check whether the following parameters in the [System information table] are

correctly configured: “BS_AG_BLKS_RES”, “CCCH-CONF”, “BS_PA_MFRMS”,

“Tx-integer“ and “MS MAX retrans”.

z Check the setting for “location updating period” in BSC and that in MSC

Check the [System information table] for the configuration of “T3212”.

The value of "T3212" in the MSC must be greater than that in the BSC.

Refer to Chapter 4 Location Update Procedure.

V. Check radio signal coverage

Due to the problem of radio signal coverage, there might be some blind coverage

areas. The MS that has entered a blind coverage area cannot receive the PAGING

REQUEST message. In that case, the MS cannot be paged.

Such cases, if any, only exist in partial areas.





8-7

8.4.4 No PAGING RESPONSE on Interface A

Through signaling tracing on interface Abis, the BSC is detected that it has received

an Establishment Indication (PAGING RESPONSE) message from the BTS but thismessage is not reported over interface A.

Such case hardly occurs and is omitted here.



Signaling Analysis ManualM900/M1800 Base Station Subsystem Chapter 9 Handover Procedure

9-1

Chapter 9 Handover Procedure

9.1 Overview

Handover procedure includes intra-BSC handover procedure, inter-BSC handover

procedure and inter-MSC handover procedure.


A handover procedure can be divided into 3 types according to different rangesinvolved in handover: intra-BSC handover procedure, inter-BSC handover procedure

and inter-MSC handover procedure.

9.2.1 Intra-BSC Handover Procedure


BTS2 BSCMSCMS

Measurement Reports From MS (1)

(12)

MS

Handover CMD

Handover Access

Handover Detect

Handover Complete

Channel ACT (2)

Channel ACT ACK (3)

(4)

(5)

(6)

SABM (8)EST IND (9)

PHY INFO (7)

BTS1

Handover Performed

(10)UA

(11)

Figure 9-1 Intra-BSC handover procedure




9-2


1) MS sends Measurement Report to BTS1 on SACCH on interface Um, and BTS1

will transfer the message to BSC.

2) BSC receives the Measurement Report. If it judges that the MS should be

handed over to another cell, it will send CHANNEL ACTIVATION to BTS2 of the

target cell to activate the channel.

3) BTS2 receives the CHANNEL ACTIVATION. If the channel type is correct, it will

turn on the power amplifier on the specified channel to receive information in the

uplink direction and send CHANNEL ACTIVATION ACKNOWLEDGE to BSC.

4) BSC receives the CHANNEL ACTIVATION ACKNOWLEDGE from BTS2 and

sends HANDOVER COMMAND to BTS1, which will transfer the command to MS.

The message is sent on FACCH on the Um interface.

5) MS receives the HANDOVER COMMAND and sends HANDOVER ACCESS onFACCH to BTS2 for access attempt.

6) BTS2 receives the HANDOVER ACCESS from MS and sends HANDOVER

DETECT to BSC notifying that the HANDOVER ACCESS message bas been

received.

7) In case of asynchronous handover, i.e., when BTS1 and BTS2 are located in

different BTSs, BTS2 will send PHY INFO on FACCH to MS while sending

HANDOVER DETECT to BSC. The PHY INFO includes such contents as the

synchronous information for correct access of MS. In case of synchronous

handover, i.e., when BTS1 and BTS2 are located in the same BTS, the PHY

INFO message will not be delivered.

8) For the asynchronous handover, MS receives the PHY INFO, and sends SABM

on FACCH to BTS2. While for the synchronous handover, MS will send SABM

soon after sending HANDOVER ACCESS.

9) BTS2 receives the first SABM, and sends EST IND to BSC, notifying it that the

radio link has been established.

10) At the same time, BTS2 sends UA frames on FACCH to MS, notifying that the

radio link layer has been established.

11) Then, MS sends HANDOVER COMPLETE on FACCH to BTS2, which transfers

the command to BSC notifying handover completion.

12) BSC sends HANDOVER PERFORMED to MSC, notifying that the handover has

been completed. At the same time, BSC initiates a local release procedure to

BTS1 to release the old channel occupied.

III. Internal handling of BSC

The internal handling of the BSC in an internal handover procedure is given below:

1) Huawei BSC performs handover decision at GLAP. Upon detecting that a call

complies with the handover initiation conditions, the GLAP sends a handover

request that carries a CGI list of the neighbor cells to the GMPU. The GMPU




9-3

then selects a neighbor cell from the list based on the cell priority (from high to

low). If the selected neighbor cell is under management of the same BSC based

on the CGI of the cell and that in the [Cell module information table] but there is

no channel available, the GMPU shall select the next neighbor cell. If theselected neighbor cell is under management of another BSC based on the CGI

of the cell and that in the [Cell module information table], the GMPU shall initiate

an inter-BSC handover procedure that is omitted here. If the selected neighbor

cell with the highest priority is under management of the same BSC and there is

a channel available, the GMPU shall initiate an intra-BSC handover procedure

and this neighbor cell is the target cell. In this case, the source cell sends an

internal handover request to the target cell and starts the 2-second timer to await

the handover preparation completion.

2) Upon receipt of the internal handover request, the target cell allocates a channel

and sends a CHANNEL ACTIVATION message to BTS2 to activate the allocated

channel.

3) Upon completion of the channel activation, the target cell sends a CHANNEL

ACTIVATION ACKNOWLEDGE message to the source cell, informing the

source cell that the channel is available. Then it starts timer T3103B1 (see [Cell

Call Control Parameter Table]) to await the HANDOVER DETECT message.

4) Upon receipt of the CHANNEL ACTIVATION ACKNOWLEDGE message, the

source cell sends a HANDOVER COMMAND message to BTS1, stops the

2-second timer and starts timer T3103A (see [Cell Call Control Parameter

Table]).

5) Upon receipt of the HANDOVER DETECT message, the target cell stops timer

T3103B1 and starts timer T3103B2 (see [Cell Call Control Parameter Table]) to

await the HANDOVER COMPLETE message.

6) Upon receipt of the HANDOVER COMPLETE message from the MS, the target

cell stops timer T3103B2 and notifies such relevant modules as AIE and AIR to

update the RR connection number. At the same time, it sends an “Internal

Handover Success” message to the source cell.

7) Upon receipt of the “Internal Handover Success” message, the source cell

initiates a local release procedure to release the old channel.

8) The target cell sends a HANDOVER PERFORMED message to the MSC,

informing the MSC that an intra-BSC handover procedure has been completed.




9-4

9.2.2 Inter-BSC Handover Procedure


(4)Channel ACT

Channel ACT ACK

BTS1 BSC1MS

SABM

Establish IND

Handover AccessHandover Detect

PHY INFO

PHY INFO

MSC BTS2 MS

Measure Report from MS

HANDOVER COMMAND

Handover REQ

Handover REQ ACKHandover CMD

Handover Detect

Handover CMPClear CMD

Clear CMP

(3)(2)Handover RQD

(1)

(12)

BSC2

(5)

(7)

(8)(9)

(10)

(11)

(6)

(13)

(14)

(15)

HANDOVER CMP (17)

(18)(19)

(20)

(16)UA

Figure 9-2 Normal inter-BSC handover procedure


Compared with the intra-BSC handover procedure, more A interface signaling are

added to the inter-BSC handover procedure. The added A interface signaling will be

described here. For the descriptions of other signaling, please see 9.2.1 Intra-BSC

Handover Procedure.

1) When an MS needs to be handed over to the cell under management of the

target BSC (BSC2), the source BSC (BSC1) sends a HANDOVER REQUIRED

message to the MSC to request outgoing BSC handover.




9-5

2) Upon receipt of the HANDOVER REQUIRED message, the MS sends a

HANDOVER REQUEST message to BSC2.

3) BSC2 activates a new channel and sends HANDOVER REQUEST

ACKNOWLEDGE to MSC, notifying MSC the channel is now available.4) Upon receipt of the HANDOVER REQUEST ACKNOWLEDGE message, the

MSC sends a HANDOVER COMMAND message to BSC1, which will transfer

the message to MS, notifying MS to access in the new channel.

5) Upon receipt of the HANDOVER COMPLETE message from BSC2, the MSC

sends a CLEAR COMMAND message to BSC1, which will initiate a local release

procedure. Then BSC1 responds to MSC with CLEAR COMPLETE, indicating

the clearance has been completed.


The internal handling of the BSC in an inter-BSC handover procedure is given below:

1) Huawei BSC performs handover decision at GLAP. Upon detecting that a call

complies with the handover initiation conditions, the GLAP sends a HANDOVER

REQUEST message that contains a CGI list of neighbor cells to the GMPU. The

GMPU then selects a neighbor cell from the list based on the cell priority (from

high to low). If the selected neighbor cell is under management of the same BSC

based on the CGI of the cell and that in the [Cell module information table], but

there is no channel available, the GMPU shall select the next neighbor cell. If the

selected neighbor cell is under management of another BSC, the GMPU shall

initiate an inter-BSC handover procedure. For the source cell in this case, the

cell under management of another BSC is the target cell and the BSC that

manages the target cell is the target BSC.

2) Upon initiation of the intra-BSC handover procedure, the source cell sends a

HANDOVER REQUIRED message to the MSC and starts the 10-second timer

(T7) to await the HANDOVER COMMAND message.

3) Upon receipt of the HANDOVER REQUEST message from the MSC, BSC2

allocates a channel based on the target cell identify in this message and

activates the allocated channel. After the activation, the target cell sends the

MSC a HANDOVER REQUEST ACKNOWLEDGE message that carries the

HANDOVER COMMAND message. In this case, the target cell starts timer

T3103B1 (see [Cell Call Control Parameter Table]) to await the HANDOVER

DETECT message.

4) When BSC1 receives the HANDOVER COMMAND message from the MSC, the

source cell sends the HANDOVER COMMAND to BTS1, which shall transfer this

message to the MS. At the same time, the source cell starts timer T3103A (see

[Cell Call Control Parameter Table]) to await handover completion. If the source

cell receives the CLEAR COMMAND message with cause “Handover Success”

before expiry of timer T3103A, BSC1 shall consider the handover procedure as

successful. If the MS returns to the old channel before expiry of this timer, BSC1




9-6

stops this timer and sends a HANDOVER FAILURE message to the MSC. If this

timer times out before reception of the CLEAR COMMAND message, BSC1 shall

consider the call in the handover procedure as dropped and send a CLEAR

REQUEST message to the MSC to release the call.5) Upon receipt of the HANDOVER DETECT message, the target cell stops timer

T3103B1, sends a HANDOVER DETECT message to the MSC and starts timer

T3103B2 to await the HANDOVER COMPLETE message.


cell stops timer T3103B2 and transfers this message to the MSC, informing the

MSC that an intra-BSC handover has been completed.

7) Upon receiving the CLEAR COMMAND message from the MSC before expiry of

timer T3103A, the source cell locally releases the radio resources and sends

back a MSC CLEAR COMMAND message.

9.2.3 Inter-MSC Handover Procedure


BTS1 BSC1MS MSC1

Measure Report from MS

(2)Handover RQD

(1)

(5)Channel ACT

BTS2 MS

Handover REQ (4)

BSC2

Channel ACT ACK (6)

Handover Access (13)

Handover REQ ACK (7)

SABM

Establish IND

Handover_Detect

PHY INFO

PHY INFO

Handover Detect

Handover CMP

(15)

(14)

(23)

(16)

(18)

(19)

HANDOVER CMP (21)

(22)

Clear CMD

Clear CMP

(24)

(25)

MSC2

(3)Perform Handover

HANDOVER COMMAND

Handover CMD (11)

(12)

(8)Radio Channel ACK

(9)IAM

(10) ACM

Send End Signal

(17)

(20)UA

Figure 9-3 Normal inter-MSC handover procedure




9-7


For the descriptions of this procedure, refer to 9.2.1 Intra-BSC Handover Procedure

and 9.2.2 Inter-BSC Handover Procedure.

Here introduces briefly the messages on the E interface:

1) Perform Handover is the message on MAP layer. It contains the CGI of source

cell and target cell and the required channel type. It informs MSC2 that a

handover will be initiated.

2) RADIO CHANNEL ACK is the message on MAP layer. It contains the information

of the new channel in the target cell and handover number.

3) INITIAL ADDRESS MESSAGE (IAM) is a TUP/ISUP message.

4) ADDRESS COMPLETE MESSAGE (ACM) is a TUP/ISUP message.

5) Send End Signal is a MAP message.


Refer to 9.2.2 III. Internal handling of BSC.

9.3 Abnormal Cases

In case of such exceptions as radio interface message loss, call drop, user hangup,

transmission failure, NSS or even BSS equipment failure, the handover procedure

might be incapable to run normally.

There are many reasons resulting in abnormal handover procedure. Only the

common cases will be described here.

9.3.1 Handover Failure Due to CIC Exception

Suppose the CIC allocated in the Handover REQ received by BSC is marked as

BLOCK, BSC will respond to MSC with HANDOVER FAILURE due to "requested

terrestrial resource unavailable".

9.3.2 Handover Failure Due to MS Access Failure

When a MS accesses the new channel, BTS cannot decode the HANDOVER

ACCESS or HANDOVER COMPLETE message correctly, and the handover will fail.

The MS returns to the old channel and responds with a HANDOVER FAILURE

message.

In the intra-BSC handover, if the BSC has not received the HANDOVER COMPLETE

message on the new channel or HANDOVER FAILURE message on the old channel

at expiry of timer T3103A, it shall consider the call as dropped and send a CLEAR




9-8

REQUEST message to the MSC on the old channel. Upon receiving the CLEAR

COMMAND message from the MSC, the BSC releases the old channel and notifies

the target cell to release the new channel. If timer T3103B1 or T3103B2 times out, the

target cell shall release the new channel.

In the inter-BSC handover procedure, if BSC1 has not received the HANDOVER

COMPLETE message at expiry of timer T3103B2, it shall send a CLEAR REQUEST

message to the MSC to release the call. If BSC2 has not received the HANDOVER

DETECT or HANDOVER COMPLETE message, it shall send a CLEAR REQUEST

message to the MSC for the same purpose.

9.3.3 Handover Procedure Initiation Failure

In case of handover procedure initiation failure, perform the following steps:1) Check whether the call complies with the handover initiation conditions

2) Check whether there is a CGI list of neighbor cells in the measurement report

3) Check whether there is any channel available for the selected neighbor cell

4) Check whether the data about the selected neighbor cell is correct, for example,

whether the CGI of the neighbor cell is consistent with that in the [Cell module

information table].

5) Log in to the BSC maintenance system. Click [Trace/GSM Trace/GSM Interface

Trace] to display the [Interface Trace] dialog box. Check whether the LAPD has

sent the GMPU a LAPD_GMPU_HO_IND message on the interface between the

GMPU and LAPD. If yes, the call complies with the handover initiation conditions.

If a neighbor cell with correct data already exists but there is still no HANDOVER

COMMAND message on interface Um, check whether the handover procedure

initiation failure is due to no channel available or another reason.



Signaling Analysis ManualM900/M1800 Base Station Subsystem Chapter 10 Ciphering Mode Setting Procedure

10-1

Chapter 10 Ciphering Mode Setting Procedure

10.1 Overview

The ciphering mode setting procedure is generally used in service requests such as

location update, service access, inter-office handover, etc. It requires the support from

GSM network equipment, especially BTS, and also depends on the encryption

support capabilities of MS.



BTS BSC MSCMS

Ciphering Mode CMP (4)

Cipher Mode CMD (1)Encryption Mode CMD (2)

Ciphering Mode CMD (3)

Cipher Mode CMP (5)

Figure 10-1 Normal ciphering mode setting procedure

1) MSC sends a CIPHER MODE COMMAND message to BSC, indicating whether

ciphering shall be used or not, which algorithm and Kc to use, and whether MSC

requests MS to include its IMEI in the CIPHER MODE COMPLETE message.

2) BSC decides which algorithm it shall adopt according to the encryption algorithm

contained in the CIPHER MODE COMMAND message, the one allowed by BSC,

and the one supported by MS, and then notifies BTS.

3) BSC sends the command CIPHER MODE COMMAND to MS, notifying it about

the selected encryption algorithm.

4) Upon receipt of the command CIPHER MODE COMMAND, MS initiates the

transmission in ciphered mode, and returns a CIPHER MODE COMPLETE

message to BSC.

5) Upon receipt of the CIPHER MODE COMPLETE message, BSC forwards the

message to MSC.




10-2


1) Encryption algorithm A5

As specified in the GSM protocols, there are total 8 encryption algorithms, i.e.

A5/0~A5/7. A5/0 indicates "Not ciphered". The ciphering mode setting procedure is

always initiated by the network. The required encryption algorithm is specified in the

encryption IE of the CIPHER MODE COMMAND message.

2) Encryption algorithm selection

When an MS initiates a call request, classmark 2 and classmark 3 may be contained

in the CM SERVICE REQUEST message. In system information, when ECSC is

equal to 1, the MS shall report classmark 3 in the CM SERVICE REQUEST message.

When ECSC is equal to 0, the MS can report classmark 3 only by changing the

classmark or through the classmark updating procedure. Therefore, it is

recommended that ECSC be configured as "1", which contains the information about

the encryption algorithm supported by MS. According to the ciphering data

configuration, MSC delivers CIPHER MODE COMMAND to BSC. BSC

comprehensively considers the encryption algorithm indicated in the command which

is allowed by MSC, the encryption algorithm allowed in BSC data configuration and

the one supported by MS which is indicated in the CM SERV REQ message, and

selects the intersection. Then BSC selects an appropriate algorithm from the

intersection by adopting the method of reverse order. In other words, algorithm

selection priorities decline in the order of A5/7 > A5/6 > A5/5 > A5/4 > A5/4 > A5/3 >

A5/2 > A5/1 > A5/0.

3) Encryption in the handover procedure

In the handover procedure, the HANDOVER REQUEST message contains an

encryption IE, which indicates the to-be-used encryption algorithm and Kc. If either of

the A interfaces of two BSSs is in Phase 1, due to the defect of the ETSI GSM Phase

I protocol (There is no ciphering mode setting IE in the handover command),

inter-BSC handover can be performed normally only when the two BSCs select the

same algorithm (e.g. merely select A5/0, or A5/2). Otherwise, special processing is

required in the destination MSC/BSC, or the originating MSC/BSC (e.g. modify the

inter-BSC handover command). Therefore, in the interconnection of A interfaces under ciphered mode, the user

should learn the difference of data configuration for the encryption function between

different manufacturers. Unsuccessful interconnection has ever occurred during a

to-BSC handover.


The internal handling of the BSC in the ciphering mode setting procedure is given

below:




10-3

1) Upon receipt of the CIPHER MODE COMMAND message from the MSC, the

BSC checks the classmark of the MS and setting for the “Encryption algorithm”

field in the [Cell configuration table].

2) The BSC takes an intersection from the encryption algorithms supported in theCIPHER MODE COMMAND message from the MSC, that defined in the [Cell

configuration table] and that specified in the CM SERVICE REQUEST message

from the MS.

3) The BSC selects an appropriate algorithm from the intersection in the reverse

order of algorithm priority. Note that the normal algorithm priority order (from high

to low) is described as A5/7 > A5/6 > A5/5 > A5/4 > A5/4 > A5/3 > A5/2 > A5/1 >

A5/0. Then the BSC sends a CIPHER MODE COMMAND message to the BTS.

10.4 Abnormal Cases

10.4.1 Ciphering Rejected

BSS shall return a CIPHER MODE REJECT message to MSC, indicating that the

encryption algorithm is not supported, if it does not support the encryption algorithm

specified in the CIPHER MODE COMMAND message.

A CIPHER MODE REJECT message shall also be returned if the MSC requests a

change of ciphering algorithm when BSS ciphering is already active.

10.4.2 MS Not Ciphered

In the following cases, the CIPHER MODE COMMAND messages shall be

considered valid:

z MS in "not ciphered" mode receives a CIPHER MODE COMMAND message,

indicating "start ciphering".

z MS in "not ciphered" mode receives a CIPHER MODE COMMAND message,

indicating "no ciphering".

z MS in "ciphered" mode receives a CIPHER MODE COMMAND message,

indicating "no ciphering".

In other cases, for example, MS in "ciphered" mode receives a CIPHER MODE

COMMAND message, indicating "ciphering", it shall regard the CIPHER MODE

COMMAND messages as erroneous, return an RR Status message with cause

"Protocol error unspecified" and take no further action.



Signaling Analysis ManualM900/M1800 Base Station Subsystem Chapter 11 Call Re-establishment Procedure

11-1

Chapter 11 Call Re-establishment Procedure

11.1 Overview

The re-establishment procedure allows MS to resume a connection in progress after

a radio link failure, possibly in a new cell or in a new location area. Whether call

re-establishment can be attempted depends on the call control state, and whether a

cell allowing call re-establishment has been found or not. During the re-establishment

procedure, the called end doesn't know the re-establishment procedure, just can't

hear voice for a short time. Call re-establishment cannot be performed for shortmessage service and call independent supplementary services.



Clear CMD

Clear CMP (4)

CL3 RE-EST REQ (6)

(3)

BTS BSC MSCMS

Clear REQ(2)

CONN FAIL IND(radio link failur e) (1)

Cipher Mode CMD (7)

Cipher Mode CMP (8)

.......

ASS REQ (9)

ASS CMP (10)

.......

Status (12)

Status Enquiry (11)

.......

Channel Reuest (5)

Figure 11-1 Call re-establishment procedure

1) After a radio link failure is detected, BTS sends a CONNECTION FAILURE

INDICATION message to BSC, with the cause value "Radio link failure".




11-2

2) BSC sends a CLEAR REQUEST message to MSC, which contains the cause for

the abnormal release.

3) Upon receipt of the message, MSC sends a CLEAR COMMAND to BSC,

requesting the release of radio resources.4) BSC initiates the release procedure, releases the physical channel resources on

Um interface, and returns a CLEAR COMPLETE message to MSC.

5) MS sends a CHANNEL REQUEST message (with the cause value of "Call

re-establishment") to BTS, and initiates the immediate assignment procedure (to

seize signaling channels).

6) MS initiates the call re-establishment procedure, by sending a CM

RE-ESTABLISHMENT REQUEST message to MSC. The MM sublayer of MS

starts timer T3230, gives an indication to all CM entities that are being

re-established, and remains in the MM sublayer state "WAIT FOR

REESTABLISH". The CM RE-ESTABLISHMENT REQUEST message contains

IMSI/TMSI, classmark 2 and CKSM.

7) MSC initiates the ciphering mode setting procedure by delivering a CIPHER

MODE COMMAND message to MS. For the specific signaling processing

procedure, please refer to Chapter 9 Ciphering Mode Setting Procedure. After

the ciphering mode setting procedure is completed, or after MS receives a CM

SERVICE ACCEPT message, timer T3230 is stopped, and MS enters the MM

sublayer state "MM CONNECTION ACTIVE".

8) BSC returns a CIPHER MODE COMPLETE message to MSC.

9) MSC sends an ASSIGNMENT REQUEST message to BSC, and initiates the

signaling processing procedure. Refer to "Assignment Procedure" of Chapter 6

Mobile Originating Call Establishment Procedure.

10) BSC returns an ASSIGNMENT COMPLETE message to MSC.

11) MSC initiates status query by sending a STATUS ENQUIRY message to MS, to

check whether the call state or MM substate is consistent.

12) MS sends a STATUS message to MSC, reporting its calling status or MM

substate.


1) In Figure 11-1, 1~4 are to release radio channel resources, are the same with

normal release procedure.

2) 5~6 refer to the immediate assignment procedure, i.e. signaling channel seizure

procedure.

3) 7~8 refer to the ciphering mode setting procedure.

4) 9~10 refer to the assignment procedure.

5) Initiating of the call re-establishment procedure

If a cell is required to support call re-establishment, the call re-establishment

parameter of the cell must be set to "Allowed", and the cell cannot be in barred state.




11-3

MS shall send a call re-establishment request in the selected cell (possibly the

previous cell, or a new cell), when it first detects a radio link failure. The previous

channel resources shall be released by BSC after the timer on BTS side expires.

After detecting the radio link failure, BTS shall send a CONNECTION FAILURE

message to BSC, indicating that radio link failure has occurred. Accordingly, BSC

shall release the corresponding radio resources, and await MS's initiating call

re-establishment.

6) MS's mode in the call re-establishment procedure

During a call re-establishment attempt, MS does not return to idle mode. Therefore,

no location updating shall be performed even if MS is not updated in the location area

of the selected cell.


None.

11.3 Abnormal Cases

11.3.1 CM Service Rejected

After receipt of a CM RE-ESTABLISHMENT REQUEST, if the RR sublayer sends an

indication that the ciphering mode setting procedure is completed, or if a CMSERVICE ACCEPT message is received, MS shall treat the indication or receipt as a

service acceptance indication, and re-enter the MM sublayer state "MM

CONNECTION ACTIVE".

If the network cannot associate the re-establishment request with any existing call for

the MS, a CM SERVICE REJECT message shall be returned with cause "Call cannot

be identified".

If call re-establishment cannot be performed for other reasons, a CM SERVICE

REJECT message shall be returned. The appropriate reject cause value may be

""IMSI unknown in VLR", "illegal ME", "network failure", "congestion", "service option

not supported", or "service option temporarily out of order".

Whatever the reject cause may be, upon receipt of the CM SERVICE REJECT

message, the MS shall stop timer T3230 and release all MM connections and

relevant RR connections.




11-4

11.3.2 Re-establishment Not Allowed or Re-establishment Failure

When MM connection is established, the MM layer may send an indication to the CC

layer. If the MM layer is disconnected, the connection may be re-established throughCC request.

If the re-establishment is not allowed, and the call is initiated within the establishment

or clearing period, the CC layer shall release MM connections.

If re-establishment is unsuccessful, MM connections shall be released, and a release

indication shall be sent to the CC layer..

11.3.3 RR Connection Failure

If random access failure or RR CONNECTION FAILURE is detected by MS, MS shall

stop timer T3230, abort the call re-establishment procedure and release all MM

connections.

If RR CONNECTION FAILURE is detected by MSC, MSC shall abort the call

re-establishment procedure and release all MM connections.



Signaling Analysis ManualM900/M1800 Base Station Subsystem Chapter 12 Directed Retry Procedure

12-1

Chapter 12 Directed Retry Procedure

12.1 Overview

A directed retry procedure is actually a type of special handover procedure. In the

assignment procedure, if there is no available radio resource in the new cell, the MS

shall be handed over to the neighbor cell. It is a type of handover from a signaling

channel to a traffic channel.


Based on the BSC and MSC that manage the serving cell and target cell, a directed

retry handover procedure can be classified into three types: directed retry intra-BSC

handover procedure, directed retry inter-BSC handover procedure and directed retry

inter-MSC handover procedure.




12-2

12.2.1 Directed Retry Intra-BSC Handover Procedure


BTS1 BSCMSMS BTS2MSC

Handover CMD


(17)


SABM (21)

EST IND (22)

PHY INFO (20)Handover Detect (19)

Handover Complete (24)

Channel ACT

Channel ACT ACK

IMM ASS CMD

Channel REQ

SABM

EST IND( CM Service REQ)CR(CM Service REQ)

CC

Setup

Call Proceeding

ASS REQ

CM Service Accepted

UA

(1)

(3)

(4)

(5)

6)

(7)(8)

(9)

(10)

(11)

(12)

(13)

(14)

Channel ACT (15)

Ass CMP (25)

(23)UA

Channel RQD (2)

Figure 12-1 Directed retry intra-BSC handover procedure

1) MS sends CHANNEL REQUEST to BTS on the access channel of the Um

interface, and then BTS will transfer the message to BSC.

2) BSC receives the CHANNEL REQUIRED, allocates a signaling channel, and

sends CHANNEL ACTIVATION back to BTS.

3) BTS receives the CHANNEL ACTIVATION, turns on the power amplifier on the

specified channel to receive information in the uplink direction if the channel typeis correct, and sends CHANNEL ACTIVATION ACKNOWLEDGE to BSC.

4) BSC receives the CHANNEL ACTIVATION ACKNOWLEDGE and sends IMM

ASSIGNMENT COMMAND to MS informing MS of the access.

5) When MS has been accessed successfully, MSC sends ASSIGNMENT

REQUEST to BSC to request for allocation of the TCH resource. If a land circuit

is needed between MSC and BSC, the ASSIGNMENT REQUEST message will

contain the related land circuit information. If there is no TCH satisfying the

requirement allocated to the serving cell at this moment, BSC will retry a

handover to hand MS over to the neighbor cell, which will provide speech service.




12-3

If the target cell is in the same BSC with the serving cell, this handover is a

directed retry intra-BSC handover.


1) (1) ~ (8) in Figure 12-1 illustrates a random access and immediate assignment

procedure, in which BSS allocates signaling channel to MS.

2) (14) ~ (24) in Figure 12-1 illustrates a TCH directed retry procedure, in which

BSS allocates such resources as speech channel and A interface circuit for MS

through handover.


Upon receiving the ASSIGNMENT REQUEST message from the MSC, if there is no

TCH available in the cell where the MS is located and if the “Direct retry” field in the

[Cell call control table] is set to “Yes”, the BSC shall initiate a directed retry handover

procedure.

The GMPU in the BSC first start the 8-second timer to await the HANDOVER

INDICATION message from the LAPD and then initiate a forced handover procedure,

as described below:

1) The GMPU sends a “Forced HANDOVER COMMAND” to the LAPD to initiate a

forced handover procedure.

2) The LAPD sends a HANDOVER INDICATION message that contains a CGI list

of the neighbor cells to the BSC. Upon receipt of this message, the BSC stopsthe 8-second timer.

3) The BSC selects a neighbor cell from the CGI list based on the cell priority (from

high to low). If the selected neighbor cell is under management of the same BSC

but there is no channel available, the BSC shall select the next neighbor cell. If

the selected neighbor cell is under management of another BSC based on the

CGI of the cell and that in the [Cell module information table], the BSC shall

initiate a directed retry inter-BSC handover procedure (see the next section). If

the selected neighbor cell with the highest priority is under management of the

same BSC based on the CGI of the cell and that in the [Cell module information

table] and there is a channel available, the BSC shall initiate a directed retry

intra-BSC handover procedure. In this case, the selected neighbor cell is the

target cell for the directed retry handover. The source cell where the call is

initiated sends an “Internal HANDOVER REQUEST” to the target cell and starts

the 2-second timer to await the handover preparation completion.

4) Upon receipt of the “Internal HANDOVER REQUEST”, the target cell allocates a

channel and notifies the target BTS (BTS2) to activate the allocated channel.

5) Upon completion of channel activation, the target cell sends a CHANNEL

ACTIVATION ACKNOWLEDGE message to the source cell, informing the




12-4

source cell that the channel is available. Then it starts timer T3103B1 (see [Cell

Call Control Parameter Table]) to await the HANDOVER DETECT message.

6) Upon receipt of the CHANNEL ACTIVATION ACKNOWLEDGE message, the

source cell sends a HANDOVER COMMAND message to BTS1, stops the2-second timer and starts timer T3103A (see [Cell Call Control Parameter Table].


T3103B1 and starts timer T3103B2 (see [Cell Call Control Parameter Table]) to

await the HANDOVER COMPLETE message.


cell stops timer T3103B2 and notifies the relevant modules such as AIE and AIR

to update the RR connection number. At the same time, it sends an “Internal

Handover Success” message to the source cell.

9) The target cell sends the MSC an ASSIGNMENT COMPLETE message that

contains target cell information, informing the MSC that the assignment has been

completed.

10) Upon receipt of the “Internal Handover Success” message, the source cell

initiates a local release procedure to release the relevant resources.




12-5

12.2.2 Directed Retry Inter-BSC Handover Procedure


Clear CMD

Clear CMP

(31)

(32)

BTS1 BSC2 MSMS BTS2MSC

Handover CMD (21)

Channel ACT

Channel ACT ACK

ASS CMD

Channel REQ

SABM


CC

Setup

Call Proceeding

ASS REQ

CM Service Accepted

UA

(1)

(3)

(4)

(5)

(6)

(7)(8)

(9)

(10)

(11)

(12)

(13)

(14)


EST IND (27)


SABM (26)

PHY INFO (25)

Handover Detect) (23)

Handover Complete (29)

Channel ACT (17)

Handover REQ

Handover REQ ACKHandover CMD

(16)(15)Handover RQD

(20)

Handover Detect (24)

(19)

BSC1

HandoverCMP (30)

(28)UA

Channel REQ (2)

Figure 12-2 Directed retry inter-BSC handover procedure


Compared to the directed retry intra-BSC handover procedure, more A interface

signaling is added to the inter-BSC handover procedure. The added A interface

signaling will be described here. For the descriptions of other signaling, see 12.2.1

Directed Retry Intra-BSC Handover Procedure.

1) If an MS needs to be handed over to a cell under management of BSC2, BSC1

shall send a HANDOVER REQUIRED message to the MSC to request an

inter-BSC handover procedure.

2) Upon receipt of the HANDOVER REQUIRED message, the MSC sends a

HANDOVER REQUEST message to BSC2.

3) Upon completion of channel activation, BSC2 sends a HANDOVER REQUEST

ACKNOWLEDGE message to the MSC, informing the MSC that the channel is

available.




12-6

4) Upon receipt of the HANDOVER REQUEST ACKNOWLEDGE message, the

MSC sends a HANDOVER COMMAND message to BSC1. BSC1 then transfers

this message to the MS, notifying the MS to access in the new channel.

5) Upon receipt of the HANDOVER COMPLETE message, the MSC sends aCLEAR COMMAND message to BSC1. Upon receiving the CLEAR COMMAND

message BSC1 initiates a local release procedure to release the old channel and

sends back a CLEAR COMPLETE message to the MSC.


Upon receiving the ASSIGNMENT REQUEST message from the MSC, if there is no

TCH available in the cell where the MS is located and if the “Direct retry” field in the

[Cell Call Control Table] is set to “Yes”, the BSC shall initiate a directed retry handover

procedure.

The GMPU in the BSC first starts the 8-second timer to await the HANDOVER

INDICATION message from the LAPD and then initiates a forced handover procedure,

as described below:

1) The GMPU sends a “Forced HANDOVER COMMAND” to the LAPD to initiate a

forced handover procedure.

2) The LAPD sends a HANDOVER INDICATION message that contains a CGI list

of the neighbor cells to the BSC. Upon receipt of this message, the BSC stops

the 8-second timer.

3) The BSC selects a neighbor cell from the CGI list based on the cell priority (fromhigh to low). If the selected neighbor cell is under management of the same BSC

but there is no channel available, the BSC shall select the next neighbor cell. If

the selected neighbor cell is under management of a different BSC based on the

CGI of the cell and that in the [Cell module information table], the BSC shall

initiate a directed retry inter-BSC handover procedure. Upon initiation of this

procedure, the source cell sends a HANDOVER REQUIRED message to the

MSC and starts the 10-second timer (T17) to await the HANDOVER COMMAND

message.

4) Upon receipt of the HANDOVER REQUEST message from the MSC, BSC2

allocates a channel to the target cell based on the target cell identity in this

message and activates the allocated channel. When the channel has been

activated, the source cell sends the MSC a HANDOVER REQUEST

ACKNOWLEDGE message that contains the HANDOVER COMMAND message.

In this case, the target cell starts timer T3103B1 (see [Cell Call Control

Parameter Table] to await the HANDOVER DETECT message.

5) When BSC1 receives the HANDOVER COMMAND message from the MSC, the

source cell sends the HANDOVER COMMAND message BTS1, which will

transfer it to the MS. At the same time, the source cell starts timer T3103A.

BSC1 considers the handover procedure as successful upon receiving the




12-7

CLEAR COMMAND message with cause “Handover Success” or “Call Control”

before expiry of timer T3103A. If the MS returns to the old channel before expiry

of this timer, BSC1 stops this timer and sends a HANDOVER FAILURE message

to the MSC. If timer T3103A times out, BSC1 shall consider the call in thehandover procedure as dropped and send a Clear Request to the MSC to

release the call.


T3103B1, transfers this message to the MSC and starts timer T3103B2 to await

the HANDOVER COMPLETE message.

7) Upon receipt of the HANDOVER COMPLETE from the MS, the target cell stops

timer T3103B2 and transfers this message to the MSC, informing the MSC that

the handover has been completed.

8) Upon receiving the CLEAR COMMAND message from the MSC before expiry of

timer T3103A, the source cell locally releases the old channel and sends back a

MSC CLEAR COMMAND message to the MSC.

12.2.3 Directed Retry Inter-MSC Handover Procedure


BTS1 BSC1MS MSC1

(2)Handover RQD

(5)Channel ACT

BTS2 MS

Handover REQ (4)

BSC2

Channel ACT ACK (6)


Handover REQ ACK (7)

SABM

Establish IND

Handover_Detect

PHY INFO

PHY INFO

Handover Detect

Handover CMP

(15)

(14)

(23)

(16)

(18)

(19)

HANDOVER CMP (21)(22)

Clear CMD

Clear CMP

(24)

(25)

MSC2

(3)Perform Handover

HANDOVER COMMAND

Handover CMD (11)

(12)

(8)Radio Channel ACK

(9)IAM

(10) ACM

Send End Signal

(17)

Ass REQ(1)

(20)UA

Figure 12-3 Directed retry inter-MSC handover procedure




12-8


Refer to 12.2.2 Directed Retry Inter-BSC Handover Procedure.

12.3 Abnormal Cases

The directed retry handover procedure might be incapable to work normally due to

radio interface message loss, call interruption, user on-hook, transmission failure or

NSS/BSS operation failure.

There are many causes for the abnormal cases. Only the typical cases will be

described here.

I. Directed retry inter-BSC handover failure due to no available channel in the

target cell

When there is no available channel in the target cell, this cell will respond with a

HANDOVER FAILURE message and the source cell will respond to MSC with

ASSIGNMENT FAILURE.

II. Directed retry intra-BSC handover failure due to CHANNEL ACTIVATION

failure

In case of CHANNEL ACTIVATION failure in the target cell, BSC responds to MSC

with ASSIGNMENT FAILURE.



Signaling Analysis ManualM900/M1800 Base Station Subsystem Chapter 13 Short Message Procedure

13-1

Chapter 13 Short Message Procedure

13.1 Overview

Short messages can be transmitted either on SDCCH or SACCH. A short message

procedure can be classified into short message calling procedure and called

procedure.




13-2


13.2.1 Short Message Procedure on SDCCH When MS Is Calling


BTS BSC MSCMS

Channel ACT

Channel ACT ACK

I MM ASS CMD

Channel REQ

CC

Authentication RPS

Authentication REQ

(1)

(3)

(4)

(5)

SABM


UA

(6)

(7)(8)

(9)

(10)

(11)

(12)

Clear CMD

Clear CMP

Channel REL

REL IND

Deactive SACCH

RF Channel REL

RF Channel REL ACK

DISC

UA

RLSD

RLSD CMP

CIPH Mode CMD (16)

CIPH Mode CMP (17)

CP ACK

CP DATA

(19)

(18)

(22)

(23)

(25)

(26)

(24)

(27)

(28)

(29)

(30)

(31)

(32)

CP ACK

CP DATA

(21)

(20)

SABM (SAPI 3)

EST IND( SAPI 3)UA

(13)

(14)(15)

Channel RQD (2)

Figure 13-1 Short message procedure on SDCCH when MS is calling




13-3


1) (1) ~ (8) in Figure 13-1 illustrates a random access and immediate assignment

procedure, in which BSS allocates signaling channel to MS.

2) (15) ~ (21) is a short message transmission procedure.

MS sends SABM again, notifying the network side that this user needs short message

service (SMS). Then, BSC provides a transparent-transmission channel for MS to

exchange short message information with MSC. In this procedure, the MSCs of some

manufacturers are capable to send ASS REQ to BSC, requesting it to assign channel

for short message transmission. The time for sending ASS REQ is the same as that

for a common call. BSC can provide SMS either by allocating other channels or by

using the original SDCCH.

Point to Point short message protocol is divided into connection management layer

(CM), relay layer (RL), transport layer (TL) and application layer (AL).

CP_DATA and CP_ACK are the messages on CM layer, CP_DATA is used to transmit

the content of RL and AL message and CP_ACK is the acknowledgement message of

CP_DATA.

3) (22) ~ (35) is a release procedure.

MSC initiates a release procedure upon the completion of short message

transmission.




13-4

13.2.2 Short Message Procedure on SDCCH When MS Is Called


BTS BSC MSCMS

Channel ACT

Channel ACT ACK

I MM ASS CMD

Channel REQ

CP_DATA

Authentication RSP

Authentication REQ

(3)

(5)

(6)

(7)

first SABM

EST IND( Page Response)CR(CMP L3 inf ormation)UA

(8)

(10)(9)

(11)

(17)

(13)

(14)

Clear CMD

Clear CMP

Channel REL

REL IND

Deactive SACCH

RF Channel REL

RF Channel REL ACK

DISC

UA

RLSD

RLSD CMP

CIPH Mode CMD (15)

CIPH Mode CMP (16)

CP ACK

CP DATA

(23)

(22)

(26)

(27)

(29)

(31)

(28)

(30)

(32)

(33)

(34)

(35)

(36)

CP ACK

CP DATA

(25)

(24)

Paging CMD

Paging CMD

first SABM

EST CNF( SAPI 3)UA

(19)

(20)(21)

EST REQ( SAPI 3)

(1)(2)

(18)

Channel RQD (4)

Figure 13-2 Short message procedure on SDCCH when MS is called




13-5


1) (1) ~ (10) is a paging response and immediate assignment procedure.

MSC sends Paging CMD to page the called subscriber. MS requests for SDCCH, and

responds with Paging Response.

2) (17) ~ (25) is a short message setup and transmission procedure.

For the short message procedure when MS is called, BSC sends EST REQ to MS to

establish short message connection. When EST CNF is received from MS, the

connection is successfully established. BSC transparently transmits the short

message till the end of the transmission. (13), (14), (15) and (16) are optional

signaling procedures.

3) (26) ~ (36) is a release procedure.




13-6

13.2.3 Short Message Procedure on SACCH When MS Is Calling


BTS BSC MSCMS

CM Servic ACC

CM Servic REQ (1)

(2)

CP ACK

CP DATA

(7)

(6)

CP ACK

CP DATA

(9)

(8)

SABM (SAPI 3)

EST IND( SAPI 3)UA

(3)

(4)

(5)

FACCH

SACCH

ACTIVE CALL

ACTIVE CALL

Figure 13-3 Short message procedure on SACCH when an MS is calling


MS sends CM SERV REQ through FACCH. MSC responds with the CM SERV ACC

message, and establishes CC layer connection. Then, it establishes RR layer

connection on SACCH, and sends the short message




13-7

13.3 Short Message Procedure on SACCH when MS IsCalled


BTS BSC MSCMS

CP ACK

CP DATA

(7)

(6)

CP ACK

CP DATA

(9)

(8)

SABM

EST CNF( SAPI 3)UA

(3)

(4)

(5)

EST REQ( SAPI 3) (2)CP DATA

ACTIVE CALL

ACTIVE CALL

(1)

Figure 13-4 Short message procedure on SACCH when an MS is called


BSC receives the CP DATA message from MSC and establishes a RR layer

connection for SMS. Upon receipt of CP ACK from the MS, MSC sends the short

message.


The internal handling of the BSC includes:

1) The BSC detects whether the MS supports short message services according to

the classmark in the message reported from the MS.




13-8

2) Upon receipt of the short message from the MS, the BSC checks the [Cell Call

Control Table] for the configuration of the “Short message uplink disabled” field.

If the field is set to yes, the short message cannot be sent.

3) Upon receipt of the short message from the MSC, the BSC checks the [Cell CallControl Table] for the configuration of the “Short message downlink disabled”

field. If the field is set to yes, the short message cannot be sent.

13.5 Abnormal Cases

In case of short message procedure failure, perform the following:

1) Check whether the MS supports short message services

2) Check the [Cell Call Control Table] for the configuration of the “Short message

uplink disabled” or “Short message uplink disabled” field. If a field is set to “Yes”,

modify the value to “No”.

3) Perform signaling tracing to check the equipment on the network side, for

example, the short message service center (SMSC). In case of short message

transmission failure, the MS receives CP DATA and responds to the MSC with

CP NACK, informing the MSC of short message transmission failure.



Signaling Analysis ManualM900/M1800 Base Station Subsystem Chapter 14 Cell Broadcast Message Procedure

14-1

Chapter 14 Cell Broadcast Message Procedure

14.1 Overview

A Cell Broadcast message procedure includes the message interaction on the

CBC-BSC interface and on the BSC-BTS interface in Cell Broadcast service.

14.2 CBC-BSC Interface Message Procedure

There are 13 messages over the interface between the CBC and BSC. They providethe following service functions:

I. Send a new message or replace the existing one

BSCCBC

Write-Replace Request (1)

Report Response (2)

Figure 14-1 Send a new message or replace the existing one

After receiving WRITE-REPLACE REQUEST, BSC will save it in the message library

if it is a new one. If it is a replace-message, BSC will delete the old one from the

message library and save the replace one in the message library. After handling the

WRITE-REPLACE REQUEST message, BSC will send REPORT RESPONSE to

CBC.




14-2

II. Delete the existing message

BSCCBC

Kill Request (1)

Report Response (2)

Figure 14-2 Delete an existing message

When receiving a KILL REQUEST message, BSC will delete the existing messagefrom the message library, and send REPORT RESPONSE to CBC.

III. CBCH status query

BSCCBC

Status CBCH Query Response

(1)

(2)

Status CBCH Query Request

Figure 14-3 CBCH status query

When the received message is STATUS CBCH QUERY Request, BSC will query the

data in the CBCH send queue, and send STATUS CBCH QUERY RESPONSE back

to CBC.

IV. Message status query

BSCCBC

Status Message Query Response

(1)

(2)

Status Message Query Request

Figure 14-4 Message status query




14-3

When receiving STATUS MESSAGE QUERY REQUEST, BSC will query the

message library for the status information of the related message, and send STATUS

MESSAGE QUERY RESPONSE back to CBC.

V. Cell reset request

BSCCBC

Restart Indication Request

(1)

(3)

Failure Indication Request

Reset Request (2)

Figure 14-5 Cell reset request in case the specified cell is normal

BSCCBC

(2)Failure Indication Request

Reset Request (1)

Figure 14-6 Cell reset request in case the specified cell is abnormal

CBC sends RESET REQUEST to BSC when initiating reset operation to the specified

cell. When BSC receives the message, if it is not correct, BSC will not process it; if it

is correct, BSC will stop sending any message to the related cell, and clear the

corresponding information from the message library and the cell broadcast table. If

the Cell Broadcast Channel of the specified cell (CBCH) is normal before the reset

operation, BSC will return RESTART INDICATION REQUEST to CBC. If the CBCH is

abnormal (due to cell fault, CBCH not configured or CBCH blocking), BSC will send

FAILURE INDICATION REQUEST back to CBC.




14-4

VI. DRX setting request

BSCCBC

Set DRX Report Response

(1)Set DRX Request

(2)

Figure 14-7 DRX setting request

When receiving the SET DRX REQUEST message, BSC should set the schedulemessage to be transmitted next time based on the parameters provided in the

message, and send SET DRX REPORT RESPONSE to CBC.

VII. Send reject response

BSCCBC

(1)Reject Response

Figure 14-8 Send reject response

When the message received by BSC is not understandable or the parameter value is

illegal, BSC will send REJECT RESPONSE to CBC to report the failure cause or brief

descriptions.




14-5

14.3 Messages and Service Functions over the Interfacebetween BSC and BTS

I. BSC sends the CBS message to the relevant BTS through a SMS Broadcast

CMD message and indicates the channel to be used.

MSBSC

(1)SMS Broadcast CMDSMS 1

SMS 2

SMS n

(1)

(2)

(3)

BTS

Figure 14-9 BSC sends a CBS message to the relevant BTS through a SMS Broadcast CMD message

II. BTS reports the current load of CBCH to BSC through the message CBCH

Loading Indication and requests BSC to implement flow control.

BTSBSC

(1)CBCH Loading Indication

Figure 14-10 BTS reports CBCH Loading Indication to BSC


The internal handling of the BSC includes:

z When the BSC supports cell broadcast service, the “Support cell broadcast flag”

field in the [Local Office Information Table] is set to “Yes”.

z A GMEM board in the BSC has been configured.




14-6

14.5 Abnormal Cases

The cell broadcast procedure generally does not involve abnormal signaling

procedure. Once the relevant parameters are correctly set to support normalcommunications, the basic cell broadcast message services can be available.



Signaling Analysis ManualM900/M1800 Base Station Subsystem Appendix A Message Interpretation

A-1

Appendix A Message Interpretation

Here will give message contents of some key interface messages, these include:

A-interface key messages, Abis-interface key messages.

A.1 A-Interface Key Messages

There is no general rule for the order of signaling elements: it happens that the same

elements appear in various orders depending on the message. The messages of

A-interface described here are based on Phase 2+ GSM 0808 version 7.6.0 Release

1998.

The key BSSMAP messages are listed in the following table:

Message Reference

ASSIGNMENT REQUEST 1.1.1

ASSIGNMENT COMPLETE 1.1.2

ASSIGNMENT FAILURE 1.1.3

HANDOVER REQUEST 1.1.4

HANDOVER REQUEST ACKNOWLEDGE 1.1.5

HANDOVER REQUIRED 1.1.6

HANDOVER REQUIRED REJECT 1.1.7

HANDOVER COMMAND 1.1.8

HANDOVER COMPLETE 1.1.9

HANDOVER FAILURE 1.1.10

HANDOVER PERFORMED 1.1.11

PAGING 1.1.12

CLEAR REQUEST 1.1.13

CLEAR COMMAND 1.1.14

CLASSMARK REQUEST 1.1.15

CLASSMARK UPDATE 1.1.16

CIPHER MODE COMMAND 1.1.17

CIPHER MODE COMPLETE 1.1.18

CIPHER MODE REJECT 1.1.19

COMPLETE LAYER 3 INFORMATION 1.1.20




A-2

A.1.1 Message Contents

I. ASSIGNMENT REQUEST

This message is sent from the MSC to the BSS via the relevant SCCP connection in

order to request the BSS to assign radio resource(s), the attributes of which are defined

within the message.

The message may also include the terrestrial circuit to be used.

INFORMATION ELEMENT REFERENCE DIRECTION TYPE

Message Type 1.2.1 MSC-BSS M 1

Channel Type 1.2.2 MSC-BSS M 5-10

Layer 3 Header Information 1.2.3 MSC-BSS O (3) 4

Priority 1.2.4 MSC-BSS O 3

Circuit Identity Code 1.2.5 MSC-BSS O (1) 3

Downlink DTX Flag 1.2.6 MSC-BSS O (2) 2

Interference Band To Be Used 1.2.7 MSC-BSS O 2

Classmark Information 2 1.2.8 MSC-BSS O (4) 4-5

Group Call Reference 1.2.9 MSC-BSS O (5) 3-8

Talker Flag 1.2.10 MSC-BSS O (6) 1

LSA Access Control Suppression 1.2.11 MSC-BSS O (8) 2

1) This element is included when the MSC allocates the A-interface circuits and the

channel type Information Element indicates speech or data, and only in those

cases.

2) This element may be included in the case of a speech TCH, and only in this case.

If not included, this has no impact on the DTX function in the BSS.

3) This information element does not serve any useful purpose. MSCs should not

send the information element unless it is required by the recipients (due to the

need to interwork with older versions of the protocol). It is expected that in future

versions of 08.08, this information element will be deleted from this message.

4) These elements may be included if the information is known by the MSC.

5) This may be included by the MSC for either a talking or listening subscriber in a

group call.

6) This information element is included for group calls, when this is included it

indicates that the mobile is a talker in the call else the mobile is a listener.

7) The information is indicated by the MSC if known.




A-3

8) This information element is included if LSA access control function shall be

suppressed in the BSS.

II. ASSIGNMENT COMPLETE

The ASSIGNMENT COMPLETE message is sent from the BSS to the MSC and

indicates that the requested assignment has been completed correctly.

The message is sent via the BSSAP SCCP connection associated with the dedicated

resource(s).

INFORMATION ELEMENT REFERENCE DIRECTION TYPE LEN

Message Type 1.2.1 BSS-MSC M 1

RR Cause 1.2.12 BSS-MSC O 2

Circuit Identity Code 1.2.5 BSS-MSC O (4) 3

Cell Identifier 1.2.13 BSS-MSC O (1) 3-10

Chosen Channel 1.2.14 BSS-MSC O (3) 2

Chosen Encryption Algorithm 1.2.15 BSS-MSC O (5) 2

Circuit Pool 1.2.16 BSS-MSC O (2) 2

Speech Version (Chosen) 1.2.17 BSS-MSC O (6) 2

LSA Identifier 1.2.18 BSS-MSC O (7) 5

1) The cell identifier is used to indicate a new cell, if during the assignment the

serving cell has changed.

2) Shall be included when several circuit pools are present on the BSS MSC

interface and a circuit was allocated by the ASSIGNMENT REQUEST message.

3) Included at least when the channel rate/type choice was done by the BSS.

4) The Circuit Identity Code information element is included mandatory by the BSS if

the BSS allocates the A-interface circuits and a circuit is needed.

5) Included at least when the encryption algorithm has been changed by the BSS.

6) Included at least when the speech version choice was done by the BSS.

7) Shall be included if current LSA in the serving cell has been identified (see GSM

03.73). Not included means that there is no current LSA in the serving cell.

III. ASSIGNMENT FAILURE

The ASSIGNMENT FAILURE message is sent from the BSS to the MSC via the

relevant SCCP connection. It indicates that there has been a failure in the assignment

process at the BSS and that the assignment procedure has been aborted.






A-4


Cause 1.2.19 BSS-MSC M 3-4



Circuit Pool List 1.2.20 BSS-MSC O (2) V


interface.

2) May be included when cause is "circuit pool mismatch" or "switch circuit pool" to

indicate circuit pool preferences.

Typical Cause values are:

- radio interface message failure,

- O and M intervention,

- equipment failure,

- no radio resource available,

- requested terrestrial resource unavailable,

- requested transcoding/rate adaption unavailable,

- terrestrial resource already allocated,

- invalid message contents,

- radio interface failure - reversion to old channel,

- directed retry,

- circuit pool mismatch,

- switch circuit pool.

requested speech version unavailable.

IV. HANDOVER REQUEST

This message is sent from the MSC to the BSS via the relevant SCCP connection to

indicate that the MS is to be handed over to that BSS.



Channel Type 1.2.2 MSC-BSS M 5-10

Encryption Information 1.2.21 MSC-BSS M (1) 3-n




A-5


Classmark Information 1 Or 1.2.22 MSC-BSS M# 2

Classmark Information 2 1.2.8 MSC-BSS M (6) 4-5

Cell Identifier (Serving) 1.2.13 MSC-BSS M 5-10

Priority 1.2.4 MSC-BSS O 3

Circuit Identity Code 1.2.5 MSC-BSS O (7) 3

Downlink DTX Flag 1.2.6 MSC-BSS O (3) 2

Cell Identifier (Target) 1.2.13 MSC-BSS M 3-10

Interference Band To Be Used 1.2.7 MSC-BSS O 2

Cause 1.2.19 MSC-BSS O (9) 3-4

Classmark Information 3 1.2.23 MSC-BSS O (4) 3-14

Current Channel type 1 1.2.24 MSC-BSS O (8) 2

Speech Version (Used) 1.2.17 MSC-BSS O (10) 2

Group Call Reference 1.2.9 MSC-BSS O (5) 3-8

Talker Flag 1.2.10 MSC-BSS O (11) 1

Configuration Evolution Indication 1.2.27 MSC-BSS O (12) 2

Chosen Encryption Algorithm(Serving)

1.2.15 MSC-BSS O (2) 2

Old BSS to New BSS Information 1.2.26 MSC-BSS O(13) 2-n

LSA Information 1.2.25 MSC-BSS O(14) 3+4n

LSA Access Control Suppression 1.2.11 MSC-BSS O (15) 2

1) If the MSC has not sent a CIPHER MODE COMMAND for this RR connection (or

has had all such CIPHER MODE COMMANDs rejected with CIPHER MODE

REJECT messages) then the MSC shall indicate that the only “permitted

algorithm” is “no encryption”.

2) If this information element is included, it shall be equal to the last received“Chosen Encryption Algorithm” information element.

3) This element may be included in the case of a speech TCH, and only in this case.

If not included, this has no impact on the DTX function in the BSS.

4) This element is included if the MSC has received such information.

5) This element is included if the MS is in a voice broadcast or voice group call.

6) One of these two elements is sent.

7) This element is included when the channel type Information Element indicates

speech or data, and only in those cases.




A-6

8) This element is included at least when the message is sent as a reaction to

reception of a HANDOVER REQUIRED message containing a “Current channel

type 1” information element. In this case it shall be equal to the received element.

9) This information element should always be included. Its cause value should be thesame as indicated in the corresponding HANDOVER REQUIRED message.

10) This element is included at least when the message is sent as a reaction to

reception of a HANDOVER REQUIRED message containing a “Speech version

(used)” information element. In this case it shall be equal to the received element.

11) This information element is included for voice group call, when this is included it

indicates that the mobile is a talker in the call else the mobile is a listener.

12) The information is indicated by the MSC if known

13) This element is included if and only if the message is sent as a reaction to the

reception of a HANDOVER REQUIRED message containing an “old BSS to new

BSS information” information element. Its contents shall be equal to the received

element.

14) This information element is included when the subscriber has localized service

area support.

15) This information element is included if LSA access control function shall be

suppressed in the BSS.

Typical cause values are:

- uplink quality,

- uplink strength,

- downlink quality,

- downlink strength

- distance,

- better cell,

- response to MSC invocation


- directed retry,

- switch circuit pool,

- traffic,

- preemption.




A-7

V. HANDOVER REQUEST ACKNOWLEDGE

This message is sent from the BSS to the MSC and indicates that the request to

support a handover at the target BSS can be supported by the BSS, and also to which

radio channel(s) the MS should be directed.


resource.


Message Type 12.1 BSS-MSC M 1

Layer 3 Information 1.2.3 BSS-MSC M (1) 11-n





Circuit Identity Code 1.2.5 BSS-MSC O (3) 3


1) This information field carries a radio interface HANDOVER COMMAND message.


interface and a circuit was allocated by the HANDOVER REQUEST message.

3) The Circuit identity code information element is included mandatory by the BSS if

the BSS allocates the A-interface circuits and a circuit is needed.

4) Included at least when the channel rate/type choice was done by the BSS.

5) Included at least when the encryption algorithm has been selected by the BSS.

6) Included at least when the speech version choice was done by the BSS.

7) Shall be included if a new potential current LSA in the target cell has been

identified (see GSM 03.73). Not included means that there is no potential current

LSA in the target cell.

VI. HANDOVER REQUIRED

This message is sent from the BSS to the MSC to indicate that for a given MS which

already has dedicated radio resource(s) assigned, a handover is required for the

reason given by the cause element.


resource(s).






A-8



Response Request 1.2.28 BSS-MSC O 1

Cell Identifier List 1.2.29 BSS-MSC M 2n+3

(Preferred) to

7n+3


Current Channel Type 1 1.2.24 BSS-MSC O (2) 2

Speech Version (Used) 1.2.17 BSS-MSC O (3) 2

Queuing Indicator 1.2.30 BSS-MSC O 2

Old BSS to New BSS Information 1.2.26 BSS-MSC O 2-n

1) Shall be included when cause "switch circuit pool" and the MSC allocates the

A-interface circuit.

2) This information element should always be included.

3) This information element should always be included when the channel mode is

speech, and only in this case.


- uplink quality,

- uplink strength,

- downlink quality,

- downlink strength,

- distance,

- better cell,

- response to MSC invocation,

- O&M intervention,

- directed retry,

- switch circuit pool,

- traffic,

- preemption.




A-9

VII. HANDOVER REQUIRED REJECT

This message is sent from the MSC to the BSS via the relevant SCCP connection. It

indicates to the BSS that the HANDOVER REQUIRED message has not resulted in

handover.



Cause 1.2.19 MSC-BSS M 3-4



- no radio resource available,

- requested terrestrial resource unavailable,

- invalid message contents,

- requested transcoding/rate adaptation unavailable,

- O and M intervention.

VIII. HANDOVER COMMAND

This message is sent from the MSC to the BSS via the relevant SCCP connection and

contains the target channel to which the MS should retune.



Layer 3 Information 1.2.31 MSC-BSS M (1) 11-n

Cell Identifier 1.2.13 MSC-BSS O 3-10

This information field carries a radio interface HANDOVER COMMAND message.

IX. HANDOVER COMPLETE

This message is sent from the BSS to the MSC via the relevant SCCP connection.

It indicates that the correct MS has successfully accessed the target cell.







A-10

X. HANDOVER FAILURE

This message is sent from the BSS to the MSC via the relevant SCCP connection. It

indicates to the MSC that there has been a failure in the resource allocation process on

handover, and that the handover has been aborted.








interface.

2) May be included when cause is "circuit pool mismatch" or "switch circuit pool" to

indicate circuit pool preferences.


- radio interface message failure;

- O and M intervention;

- Equipment failure;

- no radio resource available;

- requested terrestrial resource unavailable;

- requested transcoding/rate adaption unavailable;

- terrestrial resource already allocated;

- invalid message contents;

- radio interface failure - reversion to old channel;

- ciphering algorithm not supported;

- circuit pool mismatch;

- switch circuit pool;

- requested speech version unavailable.




A-11

XI. HANDOVER PERFORMED

This message is sent from the BSS to the MSC in order to indicate that the BSS has

performed an internal handover.

The cell identifier and (if required for O and M reasons) optionally the new channel

identity is included.


resource(s).




Cell Identifier 1.2.13 BSS-MSC M 3-10





1) Included at least when the channel rate/type has changed during the handover.

2) Included at least when the encryption algorithm has been changed by the BSS.

3) Included at least when the speech version has been changed by the BSS.

4) Shall be included if current LSA in the new serving cell has been identified (see

GSM 03.73). Not included means that there is no current LSA in the new serving

cell.

Typical Cause values: as for the handover required message, except response to MSC

invocation.

XII. PAGING

This message is sent from the MSC to the BSS and contains sufficient information toallow the paging message to be transmitted by the correct cells at the correct time.

This message is sent as a connectionless SCCP message.



IMSI 1.2.32 MSC-BSS M 3-10

TMSI 1.2.33 MSC-BSS O (1) 6

Cell Identifier List 1.2.29 MSC-BSS M 3 to 3+7n




A-12


Channel Needed 1.2.34 MSC-BSS O (2) 2

eMLPP Priority 1.2.35 MSC-BSS O (3) 2

1) This element is omitted in the exceptional case where the IMSI is used instead of

the TMSI as a paging address at the radio interface.

2) If the channel needed element is not present, the default value is assumed to be

00 (any channel).

3) If the BSS implements the eMLPP feature it should use this information element to

build the radio interface Paging request messages, otherwise the information may

be considered as an unrecognisable information element.

XIII. CLEAR REQUEST

This message is sent from the BSS to the MSC to indicate to the MSC that the BSS

wishes to release the associated dedicated resource(s).


resource(s).





- radio interface message failure,



- Joined group call channel,

- protocol error between BSS and MSC,

- preemption.

XIV. CLEAR COMMAND

This message is sent from the MSC to the BSS to instruct the BSS to release the

associated dedicated resource(s).


resource(s).




A-13




Cause 1.2.19 MSC-BSS M 3-4

This information element doesn’t serve any useful purpose. MSCs should not send the

information element unless it is required by the recipients (due to the need to interwork

with older versions of the protocol). It is expected that in future versions of 08.08, this

information element will be deleted from this message.


- call control,



- handover successful,

- protocol error between BSS and MSC.

XV. CLASSMARK REQUEST

This message is sent from the MSC to the BSS via the relevant SCCP connection

associated with that MS transaction. It requests an update of the classmark parameters

for the concerned MS.



XVI. CLASSMARK UPDATE

This message is sent from the BSS to the MSC or from the MSC to the BSS via the

relevant SCCP connection associated with that MS transaction. It updates the

classmark parameters for the concerned MS.


Message Type 1.2.1 Both M 1

Classmark Information Type 2 1.2.8 Both M 4-5

Classmark Information Type 3 1.2.23 Both O (1) 3-14




A-14

This element shall be included by the BSS if it was received from the MS. It shall be

included by the MSC if this information element has previously been received by the

MSC.

XVII. CIPHER MODE COMMAND

This message is sent from the MSC to the BSS via the relevant SCCP connection

associated with that MS transaction. It updates the encryption parameters for the

concerned MS.




Encryption Information 1.2.21 MSC-BSS M 3-n

Cipher Response Mode 1.2.36 MSC-BSS O 2

This information element doesn’t serve any useful purpose. MSCs should not send the

information element unless it is required by the recipients (due to the need to interwork

with older versions of the protocol). It is expected that in future versions of 08.08, this

information element will be deleted from this message.

XVIII. CIPHER MODE COMPLETE

This message is sent from the BSS to the MSC via the relevant SCCP connection. It

indicates that a successful cipher synchronisation has been achieved across the radio

interface.



Layer 3 Message Contents 1.2.37 BSS-MSC O 2-n


Included at least when the encryption algorithm has been selected by the BSS.

XIX. CIPHER MODE REJECT

This message is sent from the BSS to the MSC via the relevant SCCP connection

associated with that MS transaction. It indicates that the BSS is unable to perform the

requested ciphering.




A-15





- Ciphering algorithm not supported,

- Invalid message contents

XX. COMPLETE LAYER 3 INFORMATION

The message is sent from the BSS to the MSC via the BSSAP SCCP connection

established for the associated dedicated resource(s).



Cell Identifier 1.2.13 BSS-MSC M 3-10

Layer 3 Information 1.2.31 BSS-MSC M 3-n


LSA Identifier List 1.2.38 BSS-MSC O (2) 3+3n

APDU 3.2.2.68 BSS-MSC O (3) 3-n

This element is optionally used by the BSS to give the MSC a description of the channel

rate/type on which the initial layer 3 message was received.

This element shall be included at least when the current cell belongs to one or more

LSAs.

This element is optionally used by the BSS to provide Location Services related

information to MSC.

A.1.2 Signaling element coding

This paragraph contains the CODING of the signaling elements used.

The following conventions are assumed for the sequence of transmission of bits and

bytes:

z Each bit position is marked as 1 to 8. Bit 1 is the least significant bit and is

transmitted first.




A-16

z In an element octets are identified by number, octet 1 is transmitted first, then octet

2 etc.

When a field extends over more than one octet, the order of bit values progressively

decreases as the octet number increases. The least significant bit of the field isrepresented by the lowest numbered bit of the highest numbered octet of the field.

z For variable length elements a length indicator is included, this indicates the

number of octets following in the element.

z All fields within Information Elements are mandatory unless otherwise specified.

The Information Element Identifier shall always be included.

z All spare bits are set to 0.

The elements used and their CODING are:

Element Identifier Coding Element name

0000 0001 Circuit Identity Code

0000 0010 Reserved

0000 0011 Resource Available

0000 0100 Cause

0000 0101 Cell Identifier

0000 0110 Priority

0000 0111 Layer 3 Header Information

0000 1000 IMSI

0000 1001 TMSI

0000 1010 Encryption Information

0000 1011 Channel Type

0000 1100 Periodicity

0000 1101 Extended Resource Indicator

0000 1110 Number Of MSs

0000 1111 Reserved

0001 0000 Reserved

0001 0001 Reserved

0001 0010 Classmark Information Type 2


0001 0100 Interference Band To Be Used

0001 0101 RR Cause

0001 0110 Reserved

0001 0111 Layer 3 Information




A-17


0001 1000 DLCI

0001 1001 Downlink DTX Flag

0001 1010 Cell Identifier List

0001 1011 Response Request

0001 1100 Resource Indication Method


0001 1110 Circuit Identity Code List

0001 1111 Diagnostic

0010 0000 Layer 3 Message Contents

0010 0001 Chosen Channel

0010 0010 Total Resource Accessible

0010 0011 Cipher Response Mode

0010 0100 Channel Needed

0010 0101 Trace Type

0010 0110 Trigger id

0010 0111 Trace Reference

0010 1000 Transaction id

0010 1001 Mobile Identity

0010 1010 OMC Id

0010 1011 Forward Indicator

0010 1100 Chosen Encryption Algorithm

0010 1101 Circuit Pool

0010 1110 Circuit Pool List

0010 1111 Time Indication

0011 0000 Resource Situation

0011 0001 Current Channel type 1

0011 0010 Queuing Indicator

0100 0000 Speech Version

0011 0011 Assignment Requirement

0011 0101 Talker Flag

0011 0110 Connection Release Requested

0011 0111 Group Call Reference




A-18


0011 1000 eMLPP Priority

0011 1001 Configuration Evolution Indication

0011 1010 Old BSS to New BSS Information

0011 1011 LSA Identifier

0011 1100 LSA Identifier List

0011 1101 LSA Information

0011 1110 LCS QoS

0011 1111 LSA access control suppression

0100 0011 LCS Priority

0100 0100 Location Type

0100 0101 Location Estimate

0100 0110 Positioning Data

0100 0111 LCS Cause

0100 1000 LCS Client Type

0100 1001 APDU

0100 1010 Network Element Identity

0100 1011 GPS Assistance Data

0100 1100 Deciphering Keys

0100 1101 Return Error Request

0100 1110 Return Error Cause

0100 1111 Segmentation

A.1.3 Message Type

Message Type uniquely identifies the message being sent. It is a single octet element,

mandatory in all messages.

Bit 8 is reserved for future extension of the code set. All unassigned codes are spare.

8 7 6 5 4 3 2 1

0 0 0 0 0 0 0 0 Reserved.

ASSIGNMENT MESSAGES

0 0 0 0 0 0 0 1 ASSIGNMENT REQUEST

0 0 0 0 0 0 1 0 ASSIGNMENT COMPLETE




A-19

8 7 6 5 4 3 2 1

0 0 0 0 0 0 1 1 ASSIGNMENT FAILURE

HANDOVER MESSAGES

0 0 0 1 0 0 0 0 HANDOVER REQUEST

0 0 0 1 0 0 0 1 HANDOVER REQUIRED

0 0 0 1 0 0 1 0 HANDOVER REQUEST ACKNOWLEDGE

0 0 0 1 0 0 1 1 HANDOVER COMMAND

0 0 0 1 0 1 0 0 HANDOVER COMPLETE

0 0 0 1 0 1 0 1 HANDOVER SUCCEEDED

0 0 0 1 0 1 1 0 HANDOVER FAILURE

0 0 0 1 0 1 1 1 HANDOVER PERFORMED

0 0 0 1 1 0 0 0 HANDOVER CANDIDATE ENQUIRE

0 0 0 1 1 0 0 1 HANDOVER CANDIDATE RESPONSE

0 0 0 1 1 0 1 0 HANDOVER REQUIRED REJECT

0 0 0 1 1 0 1 1 HANDOVER DETECT

RELEASE MESSAGES

0 0 1 0 0 0 0 0 CLEAR COMMAND

0 0 1 0 0 0 0 1 CLEAR COMPLETE

0 0 1 0 0 0 1 0 CLEAR REQUEST

0 0 1 0 0 0 1 1 RESERVED

0 0 1 0 0 1 0 0 RESERVED

0 0 1 0 0 1 0 1 SAPI “N” REJECT

0 0 1 0 0 1 1 0 CONFUSION

OTHER CONNECTION RELATED MESSAGES

0 0 1 0 1 0 0 0 SUSPEND

0 0 1 0 1 0 0 1 RESUME

0 0 1 0 1 0 1 0 CONNECTION ORIENTED INFORMATION

0 0 1 0 1 0 1 1 PERFORM LOCATION REQUEST

0 0 1 0 1 1 0 0 LSA INFORMATION

0 0 1 0 1 1 0 1 PERFORM LOCATION RESPONSE

0 0 1 0 1 1 1 0 PERFORM LOCATION ABORT

GENERAL MESSAGES

0 0 1 1 0 0 0 0 RESET




A-20

8 7 6 5 4 3 2 1

0 0 1 1 0 0 0 1 RESET ACKNOWLEDGE

0 0 1 1 0 0 1 0 OVERLOAD

0 0 1 1 0 0 1 1 RESERVED

0 0 1 1 0 1 0 0 RESET CIRCUIT

0 0 1 1 0 1 0 1 RESET CIRCUIT ACKNOWLEDGE

0 0 1 1 0 1 1 0 MSC INVOKE TRACE

0 0 1 1 0 1 1 1 BSS INVOKE TRACE

0 0 1 1 1 0 1 0 CONNECTIONLESS INFORMATION

TERRESTRIAL RESOURCE MESSAGES

0 1 0 0 0 0 0 0 BLOCK

0 1 0 0 0 0 0 1 BLOCKING ACKNOWLEDGE

0 1 0 0 0 0 1 0 UNBLOCK

0 1 0 0 0 0 1 1 UNBLOCKING ACKNOWLEDGE

0 1 0 0 0 1 0 0 CIRCUIT GROUP BLOCK

0 1 0 0 0 1 0 1 CIRCUIT GROUP BLOCKING ACKNOWLEDGE

0 1 0 0 0 1 1 0 CIRCUIT GROUP UNBLOCK

0 1 0 0 0 1 1 1 CIRCUIT GROUP UNBLOCKING ACKNOWLEDGE

0 1 0 0 1 0 0 0 UNEQUIPPED CIRCUIT

0 1 0 0 1 1 1 0 CHANGE CIRCUIT

0 1 0 0 1 1 1 1 CHANGE CIRCUIT ACKNOWLEDGE

RADIO RESOURCE MESSAGES

0 1 0 1 0 0 0 0 RESOURCE REQUEST

0 1 0 1 0 0 0 1 RESOURCE INDICATION

0 1 0 1 0 0 1 0 PAGING

0 1 0 1 0 0 1 1 CIPHER MODE COMMAND

0 1 0 1 0 1 0 0 CLASSMARK UPDATE

0 1 0 1 0 1 0 1 CIPHER MODE COMPLETE

0 1 0 1 0 1 1 0 QUEUING INDICATION

0 1 0 1 0 1 1 1 COMPLETE LAYER 3 INFORMATION

0 1 0 1 1 0 0 0 CLASSMARK REQUEST

0 1 0 1 1 0 0 1 CIPHER MODE REJECT

0 1 0 1 1 0 1 0 LOAD INDICATION




A-21

8 7 6 5 4 3 2 1

VGCS/VBS

0 0 0 0 0 1 0 0 VGCS/VBS SETUP

0 0 0 0 0 1 0 1 VGCS/VBS SETUP ACK

0 0 0 0 0 1 1 0 VGCS/VBS SETUP REFUSE

0 0 0 0 0 1 1 1 VGCS/VBS ASSIGNMENT REQUEST

0 0 0 1 1 1 0 0 VGCS/VBS ASSIGNMENT RESULT

0 0 0 1 1 1 0 1 VGCS/VBS ASSIGNMENT FAILURE

0 0 0 1 1 1 1 0 VGCS/VBS QUEUING INDICATION

0 0 0 1 1 1 1 1 UPLINK REQUEST

0 0 1 0 0 1 1 1 UPLINK REQUEST ACKNOWLEDGE

0 1 0 0 1 0 0 1 UPLINK REQUEST CONFIRMATION

0 1 0 0 1 0 1 0 UPLINK RELEASE INDICATION

0 1 0 0 1 0 1 1 UPLINK REJECT COMMAND

0 1 0 0 1 1 0 0 UPLINK RELEASE COMMAND

0 1 0 0 1 1 0 1 UPLINK SEIZED COMMAND

I. Channel Type

This element contains all of the information that the BSS requires to determine the

required radio resource(s).

The channel type information element has a minimum length of 5 octets and a

maximum length of 10 octets. It is coded as follows:

8 7 6 5 4 3 2 1

Element identifier octet 1

Length octet 2

Spare Speech/data indicator octet 3

Channel rate and type octet 4

Permitted speech version indication / data rate + transparency indicator octet 5 or octet 5with extension*

* If the speech / data indicator (octet 3) indicates "speech" or “data”, octet 5 may

optionally be extended. Otherwise octet 5 shall not be extended.




A-22

The "speech / data indicator" field is coded as follows:

0001 Speech

0010 Data

0011 Signaling

All other values are reserved.

For values 0001 and 0010 a dedicated terrestrial resource is also required.

The "channel rate and type" is coded as follows:

If octet 3 indicates data then octet 4 shall be coded as:

0000 1000 Full rate TCH channel Bm

0000 1001 Half rate TCH channel Lm

0000 1010 Full or Half rate TCH channel, Full rate preferred, changes

allowed also after first channel allocation as a result of the request.

0000 1011 Full or Half rate TCH channel, Half rate preferred, changes

allowed also after first channel allocation as a result of the request.


not allowed after first channel allocation as a result of the request.

0001 1011 Full or Half rate TCH channel. Half rate preferred, changes

not allowed after first channel allocation as a result of the request.

0010 0xxx Full rate TCH channels in a multislot configuration, changes

by the BSS of the number of TCHs and if applicable the used radio

interface rate per channel allowed after first channel allocation as a result

of the request.

0011 0xxx Full rate TCH channels in a multislot configuration, changes

by the BSS of the number of TCHs or the used radio interface rate per

channel not allowed after first channel allocation as a result of the request.

xxx (bits 3-1) indicates maximum number of traffic channels;

321

000 1 TCHs

001 2 TCHs

010 3 TCHs

011 4 TCHs




A-23

100 5 TCHs

101 6 TCHs

110 7 TCHs

111 8 TCHs


If octet 3 indicates speech then octet 4 shall be coded as:

0000 1000 Full rate TCH channel Bm. Preference between the

permitted speech versions for full rate TCH as indicated in octet 5, 5a etc..

0000 1001 Half rate TCH channel Lm. Preference between the

permitted speech versions for half rate TCH as indicated in octet 5, 5aetc..


between full rate and half rate allowed also after first channel allocation as

a result of the request. Preference between the permitted speech

versions for the respective channel rates as indicated in octet 5, 5a etc.

0000 1011 Full or Half rate TCH channel, Half rate preferred, changes

between full rate and half rate allowed also after first channel allocation as




between full rate and half rate not allowed after first channel allocation as



0001 1011 Full or Half rate TCH channel. Half rate preferred, changes

between full rate and half rate not allowed after first channel allocation as



0000 1111 Full or Half rate TCH channel. Preference between the

permitted speech versions as indicated in octet 5, 5a etc., changes

between full and half rate allowed also after first channel allocation as a

result of the request

0001 1111 Full or Half rate TCH channel. Preference between the

permitted speech versions as indicated in octet 5, 5a etc., changes

between full and half rate not allowed after first channel allocation as a

result of the request




A-24


If octet 3 indicates signaling then octet 4 shall be coded as:

0000 0000 SDCCH or Full rate TCH channel Bm or Half rate TCHchannel Lm

0000 0001 SDCCH

0000 0010 SDCCH or Full rate TCH channel Bm

0000 0011 SDCCH or Half rate TCH channel Lm



0000 1010 Full or Half rate TCH channel, Full rate

preferred, changes allowed also after

first channel allocation as a result of

the request.

0000 1011 Full or Half rate TCH channel, Half rate

preferred, changes allowed also after


the request.

0001 1010 Full or Half rate TCH channel, Full rate

preferred, changes not allowed after


the request.

0001 1011 Full or Half rate TCH channel. Half rate

preferred, changes not allowed after


the request.


The "permitted speech version indication / data rate + transparency indicator" octet is

coded as follows:

If octet 3 indicates speech then octet 5 shall be coded as follows:




A-25

8 7 6 5 4 3 2 1

ext permitted speech version identifier octet 5

ext permitted speech version identifier octet 5a

ext permitted speech version identifier octet 5b

ext permitted speech version identifier octet 5c

ext permitted speech version identifier octet 5d

0 permitted speech version identifier octet 5e

Bit 8 indicates extension of octet 5.

0 no extension, i.e. value "0" indicates that this octet is the last octet.

1 extension, i.e. value "1" indicates that at least one additional octet is

included.

If more than one permitted speech version is indicated by octet 5 (with extension), then

the speech version choice is left to the BSS.

Bits 7-1 indicate the permitted speech version identifier;

765 4321

000 0001 GSM speech full rate version 1



000 0101 GSM speech half rate version 1



NOTE: Bits 7-1 indicate six speech versions.

The GSM speech full rate version 3 is also referred as the adaptive

multi-rate full rate speech version 1

The GSM speech half rate version 3 is also referred as the adaptive

multi-rate half rate speech version 1 All other values of permitted speech version identifiers are for future use. If an unknown

value is received and more than one octet 5 is received the sender expects the receiver

to behave as if it has made a choice of speech version.

The rules for coding preferences in octet 5, 5a - 5e are the following:




A-26

- In those cases when one specific channel rate is indicated in octet 4,

the non-empty set of permitted speech versions is included. Within this

set the permitted speech versions are included in order of speech version

preferences.

- In those cases when a preference for a channel rate is indicated in

octet 4, the non-empty sets of permitted speech versions for the

respective channel rate are included in order of the channel rate

preferences indicated in octet 4. Within a set of permitted speech versions

for a channel rate, the permitted speech versions are included in order of

speech version preferences.

- In those cases when no preference or specific channel rate is indicated

in octet 4, the permitted speech versions are included in order of speech

version preferences.

Always octet 5 has the highest preference followed by octet 5a and so on. For each

channel rate allowed by octet 4 at least one speech version shall be present.

If octet 5 indicates no extension and bits 7-1 is coded "000 0001", then the preference is

interpreted based upon the octet 4 value as follows:

- in those cases when octet 4 indicates one specific channel rate, then

“speech version 1” for the indicated channel rate is permitted.

- in those cases when octet 4 indicates a preference for a channel rate,then “speech version 1” for any of the allowed channel rates is permitted.

- in those cases when octet 4 does neither indicate a preference for a

channel rate nor a specific channel rate, then “speech version 1” for any

of the allowed channel rates is permitted and speech full rate version

1 is preferred.

If octet 3 indicates data, and octet 4 does not indicate multislot configuration, then octet

5 shall be coded as follows:

8 7 6 5 4 3 2 1

ext T/NT Rate octet 5

ext spare allowed radio interface rates octet 5a

Bit 8 indicates extension of octet 5.

0 no extension, i.e. value "0" indicates that this octet is the last octet.

1 extension, i.e. value "1" indicates that at least one additional octet is included.

Bit 7:




A-27

0 Transparent service

1 Non-transparent service.

For non-transparent service bits 6-1 indicate the radio interface data rate;

65 4321

00 0000 12 kbit/s if the channel is a full rate TCH, or

6 kbit/s if the channel is a half rate TCH

01 1000 14.5 kbit/s

01 0000 12 kbit/s

01 0001 6 kbit/s

If bit 7 in octet 5 indicates non-transparent service and octet 5a is included the ‘rate’ in

octet 5 indicates the wanted air interface data rate and the ‘allowed r i/f rates’ indicates

the other possible data rates allowed.


For transparent service bits 6-1 indicate the data rate;

65 4321

01 1000 14.4 kbit/s

01 0000 9.6 kbit/s

01 0001 4.8 kbit/s

01 0010 2.4 kbit/s

01 0011 1.2 kbit/s

01 0100 600 bit/s

01 0101 1200/75 bit/s (1200 network-to-MS / 75 MS-to-network)

If bit 7 in octet 5 indicates transparent service octet 5 shall not be extended.


Octet 5a shall be coded as follows:

Bit 8 reserved for extension.

A coding of 0 indicates no extension

Bits 4 to 1 indicate allowed radio interface data rate, per channel:

Bit 4: 0 14.5 kbit/s (TCH/F14.4) not allowed




A-28

1 14.5 kbit/s (TCH/F14.4) allowed

Bit 3: Spare





If octet 3 indicates data and octet 4 indicates Full rate TCH channels in a multislot

configuration, octet 5 and 5a shall be coded as follows;

8 7 6 5 4 3 2 1

ext T/NT Rate octet 5

ext spare allowed radio interface rates octet 5a

Octet 5 shall be coded as follows;

Bit 8: extension bit

0 indicates no extension

1 indicates that at least one additional octet is included

Bit 7: 0 Transparent service

1 Non-transparent service.

For non-transparent service bits 6-1 indicates wanted total radio interface data rate;

65 4321

01 0110 58 kbit/s (4x14.5 kbit/s)

01 0100 48.0 / 43.5 kbit/s (4x12 kbit/s or 3x14.5 kbit/s)


01 0010 24.0 / 24.0 (4x6 kbit/s or 2x12 kbit/s)


01 0000 12.0 / 12.0 kbit/s (2x6 kbit/s or 1x12 kbit/s)


For transparent service bits 6-1 indicates requested air interface user rate;

65 4321




A-29

01 1111 64 kbit/s, bit transparent

01 1110 56 kbit/s, bit transparent

01 1101 56 kbit/s

01 1100 48 kbit/s

01 1011 38.4 kbit/s

01 1010 28.8 kbit/s

01 1001 19.2 kbit/s

01 1000 14.4 kbit/s

01 0000 9.6 kbit/s


Octet 5a shall be coded as follows;

Bit 8 reserved for extension. A coding of 0 indicates no extension

Bits 4 to 1 indicates allowed radio interface data rate, per channel;

Bit 4: 0 14.5/14.4 kbit/s (TCH/F14.4) not allowed

1 14.5/14.4 kbit/s (TCH/F14.4) allowed

Bit 3: Spare

Bit 2: 0 12.0/9.6 kbit/s (TCH F/9.6) not allowed

1 12.0/9.6 kbit/s (TCH F/9.6) allowed

Bit 1: 0 6.0/4.8 kbit/s (TCH F/4.8) not allowed

1 6.0/4.8 kbit/s (TCH F/4.8) allowed

If octet 5a is not included, allowance of radio interface data rates of 12.0 and 6.0 shall

be presumed.

NOTE: For data services, the information in the channel type Information Element

is used to set the "E-bits" and map the "D-bits" (as described in GSM 04.21 and 08.20)

and to select the correct channel coding.

If octet 3 indicates signaling then octet 5 is spare.

II. Layer 3 Header Information

This element is used to supply the BSS with information that needs to be included in the

header of layer 3 messages over the radio interface.




A-30

8 7 6 5 4 3 2 1


Length octet 2

Protocol discriminator octet 3

Transaction identifier octet 4

The length indicator is a binary indication of the number of octets following in the

element.

The transaction identifier and protocol discriminator fields are coded as defined in GSM

04.08. The protocol discriminator occupies bit 1 to 4 in octet 3 of Layer 3 header

information, the Transaction identifier occupies bit 1 to 4 in octet 4 of the Layer 3 header information.

III. Priority

This element indicates the priority of the request. It is coded as follows:

8 7 6 5 4 3 2 1


Length octet 2

Priority octet 3

Octet 2 is a binary indication of the length of the rest of the element.

Octet 3 is coded as follows:

8 7 6 5 4 3 2 1

spare pci priority level qa pvi octet 1

Bit 8 is spare, set to 0

pci = Preemption Capability indicator (see note)

0 this allocation request shall not preempt an existing connection

1 this allocation request may preempt an existing connection

priority level:

6 5 4 3

0 0 0 0 spare




A-31

0 0 0 1 priority level 1 = highest priority

0 0 1 0 priority level 2 = second highest priority

1 1 1 0 priority level 14 = lowest priority

1 1 1 1 priority not used

qa = queuing allowed indicator

0 queuing not allowed

1 queuing allowed

pvi = Preemption Vulnerability indicator (see note)

0 this connection shall not be preempted by another allocation request

1 this connection might be preempted by another allocation request

NOTE: Preemption Capability indicator applies to the allocation of resources for an

event and as such it provides the trigger to the preemption procedures/processes of the

BSS. Preemption Vulnerability indicator applies for the entire duration of a connection

and as such indicates whether the connection is a target of the preemption

procedures/processes of the BSS.

IV. Circuit Identity Code

This element defines the terrestrial channel over which the call will pass.

If a 2048Kbits/s digital path is used then the circuit identification code contains in the 5

least significant bits a binary representation of the actual number of the timeslot which

is assigned to the circuit. The remaining bits in the CIC are used where necessary, to

identify one among several systems interconnecting an originating and destination

point.

The element is 2 octets in length:

8 7 6 5 4 3 2 1


a b c d e f g h octet 2

i j k X X X X X octet 3

a-k defines the PCM multiplex in use.

XXXXX define the actual timeslot in use.




A-32

The circuit identity code defines the PCM multiplex and timeslot in use at the MSC. In

cases where remultiplexing takes place between the MSC and BSS a translation may

be necessary at the BSS.

If a 1544 kbit/s digital path is used, then the format of the circuit identity code (CIC) shall

be as shown below:

The element is 2 octets in length:

8 7 6 5 4 3 2 1


CIC (least significant bits) octet 2

CIC (most significant bits) octet 3

V. Downlink DTX Flag

A fixed length element indicating whether the DTX function in the BSS is to be disabled

on a particular radio channel.

8 7 6 5 4 3 2 1


Downlink DTX flag octet 2

The Downlink DTX Flag is coded as follows:

- bits 8 to 2 are spare;

- bit 1 is set to one if the MSC forbids the BSS to activate DTX in the downlink

direction; it is set to 0 otherwise.

VI. Interference Band To Be Used

This fixed length element is coded as follows:

8 7 6 5 4 3 2 1


Band to be used octet 2

Octet 2 is coded as:

Bits 876 Spare




A-33

Bits 54321 A bit map indicating which interference bands are acceptable, the LSB

represents the least level of interference.

VII. Classmark Information Type 2

The classmark information type 2 defines certain attributes of the mobile station

equipment in use on a particular transaction.

It is coded as follows:

8 7 6 5 4 3 2 1


Length octet 2

Classmark octet 3 - 5

Octet 2 is a binary indication of the length of the remainder of the element in octets. The

length shall be determined by the length of the Mobile Station Classmark 2 element of

GSM 04.08.

The classmark octets 3, 4 and 5 are coded in the same way as the equivalent octets in

the Mobile station classmark 2 element of GSM 04.08.

VIII. Group Call Reference


8 7 6 5 4 3 2 1


Length octet 2

Descriptive group or broadcast call reference octet 3 - 8

Octet 2 is a binary indication of the length of the remainder of the element in octets.

The octets 3 to 8 are coded in the same way as the octets 2-6 in the Descriptive group

or broadcast call reference information element as defined in GSM 04.08.

IX. Talker Flag

8 7 6 5 4 3 2 1





A-34

X. LSA Access Control Suppression

This information element is included if LSA access control function shall be suppressed

in the BSS.


8 7 6 5 4 3 2 1


spare EM octet 2

If the connection is an emergency call the MSC shall set the emergency field (bit 1 of

octet 2) to 1. If the emergency field is set to 1, the BSS shall suppress exclusive access,

LSA only access and preferential access functionality.

XI. RR Cause

This fixed length element is passed from the radio interface to the MSC transparently,

when received in a GSM 04.08 message.

8 7 6 5 4 3 2 1


RR cause octet 2

Octet 2 is coded as the equivalent field from GSM 04.08.

XII. Cell Identifier

This element uniquely identifies a cell within a BSS and is of variable length containing

the following fields:

8 7 6 5 4 3 2 1


Length octet 2

Spare Cell identification discriminator octet 3

Cell identification octet 4 – n

The coding of octet 2 is a binary number indicating the length of the remaining element.

The length depends on the Cell identification discriminator (octet 3).




A-35

The coding of "Cell identification discriminator" (bits 1 to 4 of octet 3) is a binary number

indicating if the whole or a part of Cell Global Identification, CGI, according to GSM

03.03 is used for cell identification in octet 4-n. The "Cell identification discriminator" is

coded as follows:

0000 The whole Cell Global Identification, CGI, is used to identify the cell.

0001 Location Area Code, LAC, and Cell Identity, CI, is used to identify the cell.

0010 Cell Identity, CI, is used to identify the cell.

0011 No cell is associated with the transaction.


The coding of octet 4-n depends on the Cell identification discriminator (octet 3). Below

the coding is shown for each Cell identification discriminator:

Note that no coding is specified for a Cell identification discriminator value of "0011" as

no additional information is required.

Coding of Cell Identification for Cell identification discriminator = 0000

For GSM 900 and DCS 1800:

8 7 6 5 4 3 2 1

MCC dig 2 MCC dig 1 octet 4

1 1 1 1 MCC dig 3 octet 5

MNC dig 2 MNC dig 1 octet 6

LAC octet 7

LAC cont. octet 8

CI value octet 9

CI value cont octet 10

The octets 4-8 are coded as shown in GSM 04.08, Table ‘Location Area Identification

information element’ .

The octets 9-10 are coded as shown in GSM 04.08, Table ‘Cell Identity information

element’.

For PCS 1900 for NA:

8 7 6 5 4 3 2 1


MNC dig 3 MCC dig 3 octet 5




A-36

8 7 6 5 4 3 2 1


LAC octet 7

LAC cont. octet 8

CI value octet 9


The octets 4-8 are coded as shown in GSM 04.08, Table ‘Location Area Identification

information element’.


element’.


8 7 6 5 4 3 2 1

LAC octet 4

LAC cont. octet 5

CI value octet 6



8 7 6 5 4 3 2 1

CI value octet 4



element’

XIII. Chosen Channel

This Information Element contains a description of the channel allocated to the MS.

For VGCS/VBS calls this Information Element contains a description of the channel

allocated for the call in the cell.





A-37

8 7 6 5 4 3 2 1


Channel mode Channel octet 2

The channel mode field is coded as follows:

Bit 8765

0000 no channel mode indication

1001 speech (full rate or half rate)

1110 data, 14.5 kbit/s radio interface rate




1000 signaling only


The channel field is coded as follows:

Bit 4321

0000 None (Note *)

0001 SDCCH

1000 1 Full rate TCH

1001 1 Half rate TCH

1010 2 Full Rate TCHs











A-38

NOTE *: This value may be returned in the chosen channel information for

VGCS/VBS calls in the case where the BSS has decided to de-allocate resources or

allocate no resources for the call.

XIV. Chosen Encryption Algorithm

This element indicates the encryption algorithm being used by the BSS.


8 7 6 5 4 3 2 1


Algorithm identifier octet 2

The algorithm identifier caters for the possible future introduction of different user data

encryption algorithms. It is coded as;

0000 0001 No encryption used

0000 0010 GSM user data encryption version 1(A5/1).

0000 0011 GSM A5/2

0000 0100 GSM A5/3

0000 0101 GSM A5/4

0000 0110 GSM A5/5

0000 0111 GSM A5/6

0000 1000 GSM A5/7

All other values are Reserved for future international use.

XV. Circuit Pool

This element indicates the circuit pool of a circuit or group of circuits.


8 7 6 5 4 3 2 1


Circuit pool number octet 2

Predefined circuit pools are currently Circuit pool number 1 to Circuit pool number 32.




A-39

The circuit pool element is coded as follows (along with the definition of the predefined

circuit pools):

Coding Pool Supported channels and speech coding algorithms

0000 0001 Circuit poolnumber 1

FR speech version 1

FR data (12, 6, 3.6 kbit/s)


HR speech version 1

HR data (6, 3.6 kbit/s)


FR speech version 1


HR speech version 1



FR speech version 2



FR speech version 1

FR speech version 2



FR speech version 2


HR speech version 1



FR speech version 1

FR speech version 2


HR speech version 1


0000 1000 Circuit pool

number 8

HSCSD max 2 x FR data (12, 6 kbit/s)






FR speech version 1

FR speech version 2


HR speech version 1




A-40











FR speech version 1

FR speech version 2


HR speech version 1






FR data (14.5 kbit/s)


number 16

HSCSD max 2 x FR data (14.5 kbit/s)


HSCSD max 4 x FR data (14.5 kbit/s)


FR data (14.5, 12, 6, 3.6 kbit/s)


HSCSD max 2 x FR data (14.5, 12, 6 kbit/s)


FR data (14.5, 12, 6, 3.6 kbit/s)


HSCSD max 4 x FR data (14.5, 12, 6 kbit/s)0001 0100 Circuit pool

number 20FR speech version 1

FR speech version 2

FR data (14.5, 12, 6, 3.6 kbit/s)

HR speech version 1



FR speech version 1

FR speech version 2

FR data (14.5, 12, 6, 3.6 kbit/s)




A-41


HR speech version 1




FR speech version 1

FR speech version 2

FR data (14.5, 12, 6, 3.6 kbit/s)

HR speech version 1




FR speech version 3

HR speech version 3


FR speech version 3


HR speech version 3


FR speech version 1

FR speech version 2

FR speech version 3


HR speech version 3


FR speech version 1

FR speech version 2

FR speech version 3

FR data (14.5, 12, 6, 3.6 kbit/s)

HR speech version 3

0001 1011 Circuit poolnumber 27 FR speech version 1FR speech version 2

FR speech version 3


HR speech version 1

HR speech version 3



number 28

FR speech version 1

FR speech version 2




A-42


FR speech version 3

FR data (14.5, 12, 6, 3.6 kbit/s)

HR speech version 1

HR speech version 3



FR speech version 1

FR speech version 2

FR speech version 3


HR speech version 1

HR speech version 3




FR speech version 1

FR speech version 2

FR speech version 3

FR data (14.5, 12, 6, 3.6 kbit/s)

HR speech version 1

HR speech version 3




FR speech version 1

FR speech version 2

FR speech version 3


HR speech version 1

HR speech version 3




FR speech version 1

FR speech version 2

FR speech version 3

FR data (14.5, 12, 6, 3.6 kbit/s)




A-43


HR speech version 1

HR speech version 3



1000 xxxx For national/localuse

All other values are Reserved for future international use

XVI. Speech Version

This element indicates the speech version being used by the BSS.


8 7 6 5 4 3 2 1


spare Circuit pool number octet 2

The bits 7-1 of octet 2 are coded in the same way as the permitted speech version

identifier in the Channel type information element.

XVII. LSA Identifier

This element uniquely identifies a LSA and is of fixed length containing the following

fields:

8 7 6 5 4 3 2 1


Length octet 2

LSA ID octet 3

LSA ID cont. octet 4

LSA ID cont. octet 5

The octets 3-5 are coded as specified in GSM 03.03, ‘Identification of Localized Service

Area’. Bit 8 of octet 3 is the MSB.




A-44

XVIII. Cause

The cause element is used to indicate the reason for a particular event to have

occurred and is coded as shown below.

The cause value is a single octet element if the extension bit (bit 8) is set to 0. If it is set

to 1 then the cause value is a 2 octet field. If the value of the first octet of the cause field

is 1XXX 0000 then the second octet is reserved for national applications, (XXX will still

indicate the class).

8 7 6 5 4 3 2 1


Length octet 2

0/1 ext Cause Value octet 3(octet 4)

The length indicator is a binary representation of the length of the following element.

Cause Value:

Class (000): Normal event


Class (010): Resource unavailable

Class (011): Service or option not available

Class (100): Service or option not implemented

Class (101): invalid message (eg parameter out of range)

Class (110): protocol error

Class (111): interworking

In the following table, "reserved for international use" means that this code point shouldnot be used until a meaning has been assigned to it following the process of

international standardisation. "Reserved for national use" indicates code points that

may be used by operators without the need for international standardisation.

Cause value

Class Value

7 6 5 4 3 2 1

Cause Number

0 0 0 0 0 0 0 Radio interface message failure

0 0 0 0 0 0 1 Radio interface failure






A-46

Cause value

Class Value

7 6 5 4 3 2 1

Cause Number

0 1 0 1 0 0 1 Preemption

0 1 0 1 0 1 0 }

: : : : : : : } Reserved for national use

0 1 0 1 1 1 1 }

0 1 1 0 0 0 0 Requested transcoding/rateadaption unavailable

0 1 1 0 0 0 1 Circuit pool mismatch

0 1 1 0 0 1 0 Switch circuit pool

0 1 1 0 0 1 1 Requested speech versionunavailable

0 1 1 0 1 0 0 LSA not allowed

0 1 1 0 1 0 1 }

0 1 1 : : : : } Reserved for international use

0 1 1 1 1 1 1 }

1 0 0 0 0 0 0 Ciphering algorithm not supported

1 0 0 0 0 0 1 }


1 0 0 0 1 1 1 }

1 0 0 1 0 0 0 }

1 0 0 : : : : } Reserved for national use

1 0 0 1 1 1 1 }

1 0 1 0 0 0 0 Terrestrial circuit already allocated

1 0 1 0 0 0 1 Invalid message contents

1 0 1 0 0 1 0 Information element or field missing

1 0 1 0 0 1 1 Incorrect value

1 0 1 0 1 0 0 Unknown Message type

1 0 1 0 1 0 1 Unknown Information Element

1 0 1 0 1 1 0 }

1 0 1 0 1 1 1 } Reserved for international use

1 0 1 1 0 0 0 }

1 0 1 : : : : }Reserved for national use




A-47

Cause value

Class Value

7 6 5 4 3 2 1

Cause Number

1 0 1 1 1 1 1 }

1 1 0 0 0 0 0 Protocol Error between BSS andMSC

1 1 0 0 0 0 1 VGCS/VBS call non existent

1 1 0 0 0 1 0 }


1 1 0 0 1 1 1 }

1 1 0 1 0 0 0 }


1 1 0 1 1 1 1 }

1 1 1 0 0 0 0 }


1 1 1 0 1 1 1 }

1 1 1 1 0 0 0 }


1 1 1 1 1 1 1 }

XIX. Circuit Pool List

This element defines a list of BSS preferred circuit pools in order of preference.


8 7 6 5 4 3 2 1


Length octet 2

Circuit pool number (1st preferred) octet 3

:

Circuit pool number (nth preferred) octet n+2

The Circuit pool number is coded as specified in 1.2.16.




A-48

XX. Encryption Information

This element contains the user data encryption information used to control any

encryption equipment at the BSS.

It is a variable length element.


8 7 6 5 4 3 2 1


Length octet 2

Permitted algorithms octet 3

Key octet 4-n

The length indicator (octet 2) is a binary number indicating the absolute length of the

contents after the length indicator octet.

The permitted algorithms octet is a bit map indicating the A5 encryption algorithms and

no encryption. From this bit map the BSS may select an A5 algorithm or no encryption

to be used.

Bit No

1 No encryption

2 GSM A5/1

3 GSM A5/2

4 GSM A5/3

5 GSM A5/4

6 GSM A5/5

7 GSM A5/6

8 GSM A5/7

A bit position encoded as 1 indicates that the BSS may use the option represented by

that bit position. A bit position encoded as 0 indicates that the BSS shall not use the

option represented by that bit position. A permitted algorithms octet containing all bits

encoded as 0 shall not be used.

The key shall be present if at least one of the A5 encryption algorithms is permitted.

When present, the key shall be 8 octets long.








A-51

8 7 6 5 4 3 2 1


Length octet 2

spare LSA only octet 3

LSA identification and attributes 1 octet 4-7

:

LSA identification and attributes n to 3+4n


The length depends on the number of LSAs to be identified.

If the LSA only access indicator (bit 1 of octet 3) is set to 1 the subscriber has only

access to the LSAs that are defined by the LSA Information element. The LSA only

access indicator is set to 0 for allowing an emergency call.

Coding of the i-th LSA identification with attributes:

8 7 6 5 4 3 2 1

spare act pref priority octet x+1

LSA ID octet x+2

LSA ID cont. octet x+3LSA ID cont. octet x+4

Where x = 3 + 4(i-1)

Bits 1 to 4 of octet (x+1) define the priority of the LSA identification.

Bit 4321

0000 priority 1 = lowest priority

0001 priority 2 = second lowest priority

: : : :

priority 16 = highest priority

If the preferential access indicator (bit 5 of octet (x+1)) is set to 1 the subscriber has

preferential access in the LSA. If the active mode support indicator (bit 6 of octet (x+1))

is set to 1 the subscriber has active mode support in the LSA.

The octets (x+2)-(x+4) are coded as specified in GSM 03.03, ‘Identification of Localized

Service Area’. Bit 8 of octet (x+2) is the MSB.










A-55

8 7 6 5 4 3 2 1


1 1 1 1 MCC dig 3 octet 5


LAC octet 7

LAC cont. octet 8

CI value octet 9


Where x = 3 + 7(i-1).

The octets (x+1)-(x+5) are coded as shown in GSM 04.08, Table ‘Location Area

Identification information element’.

The octets (x+6)-(x+7) are coded as shown in GSM 04.08, Table ‘Cell Identity



8 7 6 5 4 3 2 1

MCC dig 2 MCC dig 1 octet x+1

MNC dig 3 MCC dig 3 octet x+2

MNC dig 2 MNC dig 1 octet x+3

LAC octet x+4

LAC cont. octet x+5

CI value octet x+6

CI value cont octet x+7

Where x = 3 + 7(i-1).





Coding of i-th Cell Identification for Cell identification discriminator = 0001

8 7 6 5 4 3 2 1

LAC octet x+1




A-56

8 7 6 5 4 3 2 1

LAC cont. octet x+2

CI value octet x+3


Where x = 3 + 4(i-1)






8 7 6 5 4 3 2 1

CI value octet x+1


Where x = 3 + 2(i-1)




For GSM 900 and DCS 1800:

8 7 6 5 4 3 2 1


1 1 1 1 MCC dig 3 octet x+2


LAC octet x+4

LAC cont. octet x+5

CI value octet x+6


Where x = 3 + 5(i-1)






A-57


8 7 6 5 4 3 2 1


MNC dig 3 MCC dig 3 octet x+2


LAC octet x+4

LAC cont. octet x+5

Where x = 3 + 5(i-1)




8 7 6 5 4 3 2 1

LAC octet x+1

LAC cont. octet x+2

Where x = 3 + 2(i-1)


Identification information element’ .

The appropriate coding for not identified cells is "0" for all bits of LAC and CI for all

possible Cell Identification Discriminator values.

XXIX. Queuing Indicator

This element contains a recommendation of the BSS concerning application of

queuing.

The element has a fixed length of two octets.

8 7 6 5 4 3 2 1


spare qri spare octet 2

Octet 2 is coded as follows:

qri = queuing recommendation indicator




A-58

0 it is recommended not to allow queuing

1 it is recommended to allow queuing

XXX. Layer 3 Information

This is a variable length element used to pass radio interface messages from one

network entity to another.

8 7 6 5 4 3 2 1


Length octet 2

Layer 3 information octet 3-n

Octet 1 identifies the element. Octet 2 gives the length of the following layer 3

information.

Octet j (j = 3, 4, ..., n) is the unchanged octet j-2 of a radio interface layer 3 message as

defined in GSM 04.08, n-2 is equal to the length of that radio interface layer 3 message.

XXXI. IMSI

The IMSI is coded as a sequence of BCD digits, compressed two into each octet. This

is a variable length element, and includes a length indicator. The remainder of thiselement is coded as defined in GSM 04.08.

The element coding is:

8 7 6 5 4 3 2 1


Length octet 2

Rest of element coded as in GSM 04.08, not including GSM 04.08 elementidentifier or GSM 04.08 octet length value

octet 3-n

XXXII. TMSI

The TMSI is a fixed length element. The TMSI is an unstructured number of 4 octets in

length.

The coding is:

8 7 6 5 4 3 2 1







A-60

XXXV. Cipher Response Mode

This information element is used by the MSC to indicate whether the IMEI is to be

included in the CIPHERING MODE COMPLETE message to be sent by the Mobile

Station.

8 7 6 5 4 3 2 1


Cipher response mode octet 2

Octet 2 is coded as:-

Bits 8,7,6,5,4,3,2 - Spare

Bit 1 = 0 - IMEISV must not be included by the Mobile Station

Bit 1 = 1 - IMEISV must be included by the Mobile Station

XXXVI. Layer 3 Message Contents

This is a variable length element used to pass the contents (from octet 3 up to the last

octet) of radio interface messages from one network entity to another.

8 7 6 5 4 3 2 1


Length octet 2

Layer 3 message contents octet 3-n

The length indicator (octet 2) is a binary number indicating the absolute length of the

contents after the length indicator octet.

Octet j (j = 3, 4, ..., n) is the unchanged octet j of a radio interface layer 3 message as

defined in GSM 04.08, n is equal to the length of that radio interface layer 3 message.

XXXVII. LSA Identifier List

This element uniquely identifies LSAs and is of variable length containing the following

fields:

8 7 6 5 4 3 2 1


Length octet 2

spare EP octet 3




A-61

8 7 6 5 4 3 2 1

LSA identification 1 octet 4-6

: :

LSA identification 2 to 3+3n


The length depends on the number of LSAs to be identified. If the escape PLMN (see

GSM 03.73) is broadcast the EP bit (bit 1 of octet 3) is set to 1, otherwise it is set to 0.

8 7 6 5 4 3 2 1

LSA ID octet x+1

LSA ID cont. octet x+2

LSA ID cont. octet x+3

Where x = 3 + 3(i-1)

The octets (x+1)-(x+3) are coded as shown in GSM 03.03, ‘Identification of Localized

Service Area’. Bit 8 of octet (x+1) is the MSB.

XXXVIII. APDU

This information element is defined as a general container for passing information

transparently between BSSs or between BSS and SMLC via the MSC.


8 7 6 5 4 3 2 1


Length octet 2-3

APDU octet 4-n

The length indicator is a binary indication of the number of octets following in the

element.

The APDU octets 4 to n are coded in the same way as the equivalent octet in the APDU

element of GSM 09.31.




A-62

A.2 Abis-Interface Key Messages1

There is no general rule for the order of signaling elements: it happens that the same

elements appear in various orders depending on the message.

The key BSSMAP messages are listed in the following table:

Message name Reference

CHANNEL REQUIRED 2.1.1

PAGING COMMAND 2.1.2

CHANNEL ACTIVATION 2.1.3

CHANNEL ACTIVATION ACKNOWLEDGE 2.1.4

CHANNEL ACTIVATION NEGATIVE ACKNOWLEDGE 2.1.5

IMMEDIATE ASSIGN COMMAND 2.1.6

CONNECTION FAILURE INDICATION 2.1.7

ERROR INDICATION 2.1.8

ENCRYPTION COMMAND 2.1.9

HANDOVER DETECTION 2.1.10

MODE MODIFY 2.1.11

MODE MODIFY ACKNOWLEDGE 2.1.12

MODE MODIFY NEGATIVE ACKNOWLEDGE 2.1.13

ESTABLISH INDICATION 2.1.14

A.2.1 Message Contents

I. CHANNEL REQUIRED

This message is sent from BTS to BSC to indicate the reception of a CHANnel

REQuest message (special access burst message) from an MS.

INFORMATION ELEMENT REFERENCE PRESENCE FORMAT LENGTH

Message discriminator 2.2.1 M V 1

Message type 2.2.2 M V 1

1The messages of Abis-interface described here are based on Phase 2+ GSM 0858 version

7.4.1 Release 1998.




A-63


Channel number 2.2.3 M TV 2

Request Reference 2.2.4 M TV 4

Access Delay 2.2.5 M TV 2

Physical Context 2.2.6 O 1) TLV >=2

Optional element for additional physical channel information.

The Request Reference element contains the random access reference value sent by

MS in the CHANnel REQuest message and some low order bits of the absolute frame

number for the reception of the access burst.

II. PAGING COMMAND

This message is sent from BSC to BTS to request the paging of an MS.





Paging Group 2.2.7 M TV 2

MS Identity 2.2.8 M TLV 2-10

Channel Needed 2.2.9 O 1) TV 2

eMLPP Priority 2.2.10 O 2) TV 3

1) If the Channel Needed element is not present, the default value is assumed to be

00 (any channel).

2) If the eMLPP Priority is not present then the BTS does not include the eMLPP

priority in the radio interface message.

The Paging Group element is used by BTS to calculate the correct DRX paging block to

be used for the transmission of the PAGing REQuest message as defined in

GSM 05.02.

III. CHANNEL ACTIVATION

This message is sent from BSC to BTS in order to activate a radio channel. The

attributes of the channel are defined in the message.




A-64





Activation Type 2.2.11 M TV 2

Channel Mode 2.2.12 M TLV 8-9

Channel Identification 2.2.13 O 7) TLV 8

Encryption information 2.2.14 O 1) TLV >=3

Handover Reference 2.2.15 C 2) TV 2

BS Power 2.2.16 O 3) TV 2

MS Power 2.2.17 O 3) TV 2

Timing Advance 2.2.18 C 3) 4) TV 2

BS Power Parameters 2.2.20 O 5) TLV >=2

MS Power Parameters 2.2.19 O 5) TLV >=2

Physical Context 2.2.6 O 6) TLV >=2

SACCH Information 2.2.21 O 8) TLV >=3

UIC 2.2.22 O 9) TLV 3

Main channel reference 2.2.23 O 10) TV 2

MultiRate configuration 2.2.24 O 11) TLV >=4

MultiRate Control 2.2.25 O 12) TV 2

Supported Code Types 2.2.26 O 12) TLV >=5

1) The Encryption Information element is only included if ciphering is to be applied.

2) The Handover Reference element is only included if activation type is handover.

3) If BS Power, MS Power and/or Timing Advance elements are present, they are to

be used to set the initial transmission power and the initial L1-header.

4) The Timing Advance element must be included if activation type is intra cell

channel change.

5) The BS and MS Power Parameters elements are included to indicate that BS

and/or MS power control is to be performed by BTS. The maximum power to be

used is indicated in the BS and MS Power elements respectively.

6) Optional element for additional physical channel information.

7) Included if compatibility with phase1 is required.

8) Optional element for setting the SACCH filling information individually for this

channel. If this element is present, the SACCH filling information as given by this

element shall be used for this channel (replacing any SACCH filling information as




A-65

given by the SACCH FILLING message(s)) until the channel is released or the

information is changed by a SACCH INFO MODIFY message. (If this element is

not present, the SACCH filling as given by the SACCH FILLING message(s) shall

be used.)9) The UIC element may be included for voice group calls. It is used in the same way

as the BSIC for decoding the random access bursts when decoding uplink access

bursts. If not included, the BSIC shall be used for decoding uplink access bursts.

10) Optional element for multislot operation, it may be used in case of power control in

the BTS.

11) Included if the Channel Mode indicates that a multi-rate speech code is used.

12) Optionally included if the Channel Mode indicates that a multi-rate speech code is

used and TFO control is required or to give to the BTS the possibility to change

autonomously the multi-rate code configuration.

IV. CHANNEL ACTIVATION ACKNOWLEDGE

This message is sent from BSC to BTS to acknowledge that the requested channel

activation has been completed correctly.





Frame number 2.2.27 M TV 3

The Frame Number element is used by BSC to calculate the Starting Time parameter

when required.

V. CHANNEL ACTIVATION NEGATIVE ACKNOWLEDGE

This message is sent from BTS to BSC to indicate that the channel activation could not

be performed as requested.





Cause 2.2.28 M TLV >=3

If the Channel Activation message was received with an erroneous Channel number

information element, the Channel Activation Negative Acknowledge message is




A-66

returned with the Channel Number information element equal to the received (and

erroneous) Channel number and the Cause value "Mandatory Information Element

Error" with Diagnostics equal to the Channel number element identifier value.

VI. IMMEDIATE ASSIGN COMMAND

This message is sent from BSC to BTS to request the transmission of an immediate

assignment message.





Full Imm. Assign Info 2.2.29 M TLV 25

The Full Imm. Assign Info element contains the relevant immediate assignment

message as defined in GSM 04.08 (IMMEDIATE ASSIGNMENT or IMMEDIATE

ASSIGNMENT EXTENDED or IMMEDIATE ASSIGNMENT REJECT) with the "Page

Mode" element set to the value "no change".

VII. CONNECTION FAILURE INDICATION

This message is sent from BTS to BSC to indicate that an active connection has been

broken for some reason.






VIII. ERROR INDICATION

This message is sent from BTS to BSC to indicate an abnormal case for a radio link

layer connection.








A-67


Link Identifier 2.2.30 M TV 2

RLM Cause 2.2.31 M TLV 2-4

IX. ENCRYPTION COMMAND

This message is sent from BSC to BTS to start ciphering mode operation.





Encryption information 2.2.14 M TLV >=3


L3 Info (CIPH MOD CMD) 2.2.32 M TLV 6

The L3 Info element contains the complete Ciphering Mode Command message as

defined in GSM 04.08.

X. HANDOVER DETECTION

This message is sent from BTS to BSC when BTS correctly receives information from

an MS on the handover activated channel.





Access Delay 2.2.5 O 1) TV 2

The Access Delay element is included if the sending of the handover detection

message was triggered by the reception of a handover access burst with the correct

handover reference.

XI. MODE MODIFY

This message is sent from BSC to BTS to request a change of channel mode of an

active channel.




A-68





Channel Mode 2.2.12 M TLV 8-9

Encryption information 2.2.14 O 1) TLV >=3

Main channel reference 2.2.23 O 2) TV 2

MultiRate configuration 2.2.24 O 3) TLV >=3

Multirate Control 2.2.25 O 4) TV 2

Supported Code Types 2.2.26 O 4) TLV >=5

1) The Encryption Information element is only included if ciphering is to be applied.

2) Optional element for multislot operation, it may be used in case of power control in

the BTS.

3) Included if the Channel Mode indicates that a multi-rate speech code is used.

4) Optionally included if the Channel Mode indicates that a multi-rate speech code is

used and TFO control is required or to give to the BTS the possibility to change

autonomously the multi-rate code configuration.

XII. MODE MODIFY ACKNOWLEDGE

This message is sent from BTS to BSC to confirm the change of channel mode of an

active channel.





XIII. MODE MODIFY NEGATIVE ACKNOWLEDGE

This message is sent from BTS to BSC to indicate that the channel mode modification

could not be performed as requested.








A-69



XIV. ESTABLISH INDICATION

This message is sent from BTS to BSC to indicate the establishment of a radio link

layer connection in multi-frame mode, initiated by an MS.






L3 Information 2.2.32 O 1) TLV 3-23

The L3 Information field is present only if the SABM frame contained a non-empty

information field.

NOTE: The "establish mode" parameter appearing in GSM 04.06 is used only on

the MS side.

A.2.2 Signaling element coding

I. Message discriminator

A 1 octet field is used in all messages to discriminate between Transparent and

Non-Transparent messages and also between Radio Link Layer Management,

Dedicated Channel Management, Common Channel Management and TRX

Management messages.

8 7 6 5 4 3 2 1

G7 G6 G5 G4 G3 G2 G1 T

The T-bit is set to 1 to indicate that the message is to be/was considered transparent by

BTS. All other messages shall have the T-bit set to 0.

The G-bits are used to group the messages as follows:

G7 G6 G5 G4 G3 G2 G1 Message Group

0 0 0 0 0 0 0 reserved




A-70

G7 G6 G5 G4 G3 G2 G1 Message Group

0 0 0 0 0 0 1 Radio Link Layer Management messages

0 0 0 0 1 0 0 Dedicated Channel Management messages

0 0 0 0 1 1 0 Common Channel Management messages

0 0 0 1 0 0 0 TRX Management messages

0 0 1 0 0 0 0 Location Services messages

All other values are reserved for future use

II. MESSAGE TYPE

The Message Type uniquely identifies the function of the message being sent. It is asingle octet and coded in the following way:

8 7 6 5 4 3 2 1

EM Message type

Bit 8 is the extension bit and is reserved for future use. The following message types

are used (all other values are reserved):

8 7 6 5 4 3 2 1 Message

0 0 0 0 - - - - Radio Link Layer Management messages

0 0 0 1 DATA REQuest

0 0 1 0 DATA INDication

0 0 1 1 ERROR INDication

0 1 0 0 ESTablish REQuest

0 1 0 1 ESTablish CONFirm

0 1 1 0 ESTablish INDication

0 1 1 1 RELease REQuest

1 0 0 0 RELease CONFirm

1 0 0 1 RELease INDication

1 0 1 0 UNIT DATA REQuest

1 0 1 1 UNIT DATA INDication

0 0 0 1 - - - - Common Channel Management/TRX Management




A-71

8 7 6 5 4 3 2 1 Message

messages

0 0 0 1 BCCH INFOrmation

0 0 1 0 CCCH LOAD INDication

0 0 1 1 CHANnel ReQuireD

0 1 0 0 DELETE INDication

0 1 0 1 PAGING CoMmanD

0 1 1 0 IMMEDIATE ASSIGN COMMAND

0 1 1 1 SMS BroadCast REQuest

1 0 0 1 RF RESource INDication

1 0 1 0 SACCH FILLing

1 0 1 1 OVERLOAD

1 1 0 0 ERROR REPORT

1 1 0 1 SMS BroadCast CoMmanD

1 1 1 0 CBCH LOAD INDication

1 1 1 1 NOTification CoMmanD

0 0 1 - - - - - Dedicated Channel Management messages

0 0 0 0 1 CHANnel ACTIVation

0 0 0 1 0 CHANnel ACTIVation ACKnowledge

0 0 0 1 1 CHANnel ACTIVation Negative ACK

0 0 1 0 0 CONNection FAILure

0 0 1 0 1 DEACTIVATE SACCH

0 0 1 1 0 ENCRyption CoMmanD

0 0 1 1 1 HANDOver DETection

0 1 0 0 0 MEASurement RESult

0 1 0 0 1 MODE MODIFY REQuest

0 1 0 1 0 MODE MODIFY ACKnowledge

0 1 0 1 1 MODE MODIFY Negative ACKnowledge

0 1 1 0 0 PHYsical CONTEXT REQuest

0 1 1 0 1 PHYsical CONTEXT CONFirm

0 1 1 1 0 RF CHANnel RELease

0 1 1 1 1 MS POWER CONTROL

1 0 0 0 0 BS POWER CONTROL




A-72

8 7 6 5 4 3 2 1 Message

1 0 0 0 1 PREPROCess CONFIGure

1 0 0 1 0 PREPROCessed MEASurement RESult

1 0 0 1 1 RF CHANnel RELease ACKnowledge

1 0 1 0 0 SACCH INFO MODIFY

1 0 1 0 1 TALKER DETection

1 0 1 1 0 LISTENER DETection

1 0 1 1 1 REMOTE CODE CONFiguration REPort

1 1 0 0 0 Round Trip Delay REPort

1 1 0 0 1 PRE-HANDOver NOTIFication

1 1 0 1 0 MultiRate CODE MODification REQest

1 1 0 1 1 MultiRate CODE MOD ACKnowledge

1 1 1 0 0 MultiRate CODE MOD Negative ACKnowledge

1 1 1 0 1 MultiRate CODE MOD PERformed

1 1 1 1 0 TFO REPort

1 1 1 1 1 TFO MODification REQuest

0 1 - - - - - - Location Service messages

0 0 0 0 0 1 Location Information

III. Channel Number

In the direction BSC to BTS the Channel Number parameter is used to indicate on

which physical channel/subchannel the message is to be sent. In the direction BTS to

BSC the Channel Number indicates on which physical channel/subchannel the

message was received. It is coded in two octets as follows:

8 7 6 5 4 3 2 1

Element identifier

C5 C4 C3 C2 C1 TN

The C-bits describe the channel as follows:

C5 C4 C3 C2 C1

0 0 0 0 1 Bm + ACCH's

0 0 0 1 T Lm + ACCH's




A-73

C5 C4 C3 C2 C1

0 0 1 T T SDCCH/4 + ACCH

0 1 T T T SDCCH/8 + ACCH

1 0 0 0 0 BCCH

1 0 0 0 1 Uplink CCCH (RACH)

1 0 0 1 0 Downlink CCCH (PCH + AGCH)

The T-bits indicate, coded in binary, the sub-channel number as specified in

GSM 05.02.

TN is time slot number, binary represented as in GSM 05.02.

IV. Request Reference

This element carries the Request Reference parameters used for contention resolution

on RACH.

8 7 6 5 4 3 2 1

Element identifier 1

RA 2

T1' T3 (high) 3

T3 (low) T2 4

Octets 2-4 are coded as the corresponding fields of the Request Reference element of

GSM 04.08. (Octet 2, RA, is the Random Access Information field set by MS in the

CHANnel REQuest message. Octets 3-4 contain the absolute frame number modulo

42432 for the frame number when the access burst was received, see Starting Time

information element of GSM 04.08).

V. Access Delay

This element contains the delay of the access burst as measured by BTS at random

access or at handover access.

8 7 6 5 4 3 2 1


Access Delay 2




A-74

The Access Delay field contains the delay of the access burst as measured by BTS.

The delay is expressed as defined for the Timing Advance TA in GSM 05.10 but with

the range extended to 8 bits, i.e. the six least significant bits of the field correspond to

the Timing Advance.

VI. Physical Context

This element contains supplementary information on the transmission/reception

process. It is a variable length element.

8 7 6 5 4 3 2 1


Length 2

Physical 3

Context

Information N

The Physical Context Information field is not specified. This information should not be

analyzed by BSC, but merely forwarded from one TRX/channel to another.

VII. Paging Group

This element carries the paging population of an MS to be paged.

8 7 6 5 4 3 2 1


Paging Group 2

The Paging Group field (octet 2) contains the binary representation of the paging group

as defined in GSM 05.02.

VIII. MS Identity

This element carries the identity of an MS (TMSI or IMSI). It is a variable length

element.

8 7 6 5 4 3 2 1


Length 2

3




A-75

8 7 6 5 4 3 2 1

:MS Identity

N

The MS Identity field (octets 3-N) is coded as specified for the Mobile Identity

information element of GSM 04.08, octets 3-N.

IX. Channel Needed

This information element is used to indicate to the mobile station which channel will be

needed for the transaction linked to the paging procedure.

8 7 6 5 4 3 2 1


Reserved for future use Channel 2

The Channel Field (bits 1-2 of octet 2) indicates the further combination of channel

which will be needed. It is coded as follows:

Value Channel Needed.

0 0 Any Channel.

0 1 SDCCH.

1 0 TCH/F (Full rate).

1 1 TCH/F or TCH/H (Dual rate).

X. eMLPP Priority

This Information Element contains the eMLPP priority of the call.


8 7 6 5 4 3 2 1


spare call priority 2

The call priority field (bit 3 to 1 of octet 2) is coded in the same way as the call priority

field (bit 3 to 1 of octet 5) in the Descriptive group or broadcast call reference

information element as defined in GSM 04.08.




A-76

XI. Activation Type

This element is used to indicate the type of activation requested in the CHANnel

ACTIVation message. It is coded in two octets as follows:

8 7 6 5 4 3 2 1


R Reserved A3 A2 A1 2

The R bit indicates if the procedure is an initial activation or a reactivation.

R

0 - Initial activation

1 - Reactivation

The A-bits indicate the type of activation, which defines the access procedure and the

operation of the data link layer, as follows:

A3 A2 A1

0 0 - Activation related to intra-cell channel change

0 - related to immediate assignment procedure

1 - related to normal assignment procedure

0 1 - Activation related to inter-cell channel change (handover)

0 - related to asynchronous handover procedure

1 - related to synchronous handover procedure

1 0 - Activation related to secondary channels

0 - related to additional assignment procedure

1 - related to multislot configuration

All other values reserved for future use.

NOTE: For the main TCH channel in a Multislot configuration activation types for

intra-cell and inter-cell channel change are used.

XII. Channel Mode

This element gives information on the mode of coding/decoding and transcoding/rate

adaption of a channel.




A-77

8 7 6 5 4 3 2 1


Length 2

Reserved for future use DTXd DTXu 3

Speech or data indicator 4

Channel rate and type 5

Speech coding algor./data rate + transp ind 6

The DTX bits of octet 3 indicate whether DTX is applied:

1 DTX is applied

0 DTX is not applied.

DTXd indicates use of DTX in the downlink direction (BTS to MS) and DTXu indicates

use of DTX in the uplink direction (MS to BTS).

The "Speech or data indicator" field (octet 4) is coded as follows:

0000 0001 Speech

0000 0010 Data

0000 0011 Signaling


The "Channel rate and type" field (octet 5) is coded as follows:

0000 0001 SDCCH



0000 1010 Full rate TCH channel bi-directional Bm, Multislot configuration

0001 1010 Full rate TCH channel uni-directional downlink Bm, Multislot configuration

0001 1000 Full rate TCH channel Bm Group call channel

0001 1001 Half rate TCH channel Lm Group call channel

0010 1000 Full rate TCH channel Bm Broadcast call channel

0010 1001 Half rate TCH channel Lm Broadcast call channel







A-79

01 0001 4.8 kbit/s

01 0010 2.4 kbit/s

01 0011 1.2 kbit/s

01 0100 600 bit/s

01 0101 1 200/75 bit/s (1 200 network-to-MS, 75 MS-to-network)


XIII. Channel Identification

This information element describes some aspects of a channel together with its

SACCH.

8 7 6 5 4 3 2 1


Length 2

04.08 "Channel Description" *

04.08 "Mobile Allocation" *

A * denotes that the whole of the 04.08 element including the element identifier and

length should be included. The 04.08 "Mobile Allocation" shall for compatibility reasons

be included but empty, i.e. the length shall be zero.

XIV. Encryption information

This element is a variable length element. It contains necessary information to control

encryption devices.

8 7 6 5 4 3 2 1


Length 2

Algorithm identifier 3

Key 4

n




A-80

The Algorithm Identifier field (octet 3) indicates the relevant ciphering algorithm. It is

coded as:

0000 0000 Reserved

0000 0001 No encryption shall be used.

0000 0010 GSM encryption algorithm version 1 (A5/1)

0000 0011 GSM A5/2

0000 0100 GSM A5/3

0000 0101 GSM A5/4

0000 0110 GSM A5/5

0000 0111 GSM A5/6

0000 1000 GSM A5/7

All other values are reserved

The Key field (octets 4-n) indicates the ciphering key. It shall be an integral number of

octets and the length is given as the value of the Length field minus 1.

XV. Handover reference

The information is coded in two octets and contains the handover reference value.

8 7 6 5 4 3 2 1


Handover reference 2

The Handover Reference octet contains the handover reference value as defined in

GSM 04.08.

XVI. BS Power

This information element indicates the TRX transmission power level on a particular

channel.

8 7 6 5 4 3 2 1


Reserved Power Level 2




A-81

The Power Level field (octet 2) indicates the number of 2 dB steps by which the power

shall be reduced from its nominal value, Pn, set by the network operator to adjust the

coverage. Thus the Power Level values correspond to the following powers (relative to

Pn):

Value Power level

0 0 0 0 0 Pn

0 0 0 0 1 Pn - 2 dB

0 0 0 1 0 Pn - 4 dB

0 1 1 1 0 Pn - 28 dB

0 1 1 1 1 Pn - 30 dB

All other values are reserved for future use.

See also GSM 05.05, subclass 4.1.2 and GSM 05.08, subclass 4.5.

XVII. MS Power

This element carries the power level of MS.

8 7 6 5 4 3 2 1


Reserved Power Level 2

The coding and meaning of the Power Level field is as defined in GSM 05.05 and

GSM 05.08. See also GSM 04.04.

XVIII. Timing Advance

This element contains the timing advance to be used by MS in subsequent

communications. It is calculated by BTS at the reception of a CHANnel REQuest

message (random access burst) or a handover access burst.

8 7 6 5 4 3 2 1


Reserved Timing Advance 2

The Timing Advance field contains the timing advance TA as specified in GSM 05.10.

Bits 7-8 of octet 2 are reserved for future use.




A-82

XIX. MS Power Parameters

This element carries the parameters required by TRX for MS power control.

8 7 6 5 4 3 2 1


Length 2

MS Power Control

3

Parameters

N

The MS Power Control Parameters field contains the parameters and limits required

when MS power control is to be performed by BTS. The coding is operator dependant.

Examples of possible parameters and algorithms can be found in GSM 05.08 (RXLEV,

RX-QUAL-FULL, RX-QUAL-SUB, DISTANCE (Timing Advance) etc.).

XX. BS Power Parameters

This element carries the parameters required by TRX for control of its own transmission

power.

8 7 6 5 4 3 2 1


Length 2

3

:

BS Power Control

Parameters

N

The BS Power Control Parameters field contains the parameters and limits required

when TRX transmission power control is to be performed by BTS. The coding is

operator dependant. Examples of possible parameters and algorithms can be found in

GSM 05.08 (RXLEV, RX-QUAL-FULL, RX-QUAL-SUB, DISTANCE (Timing Advance)

etc.).

XXI. SACCH Information

This element is used to carry the SACCH filling information (System Information

messages, or EXTENDED MEASUREMENT ORDER message) that is to be used on a

specific channel.




A-83

8 7 6 5 4 3 2 1


Length 2

Number of messages 3

Type of 1st message 4

Length of 1st message 5

1st message :

j

Type of n'th message l

Length of n'th message l+1

N

n'th message

The Length field (octet 2) indicates in binary the total remaining length of the element

(octets 3 - N).

The Number of SI messages field (octet 3) indicates in binary the number of messages

contained in the element.

The coding of each of these messages consists of a type field (Type of n’th msg), a

length field (Length of n’th message) and a message field (n’th message).

The "Type of n’th msg" field indicates the type of SYSTEM INFORMATION, or an

EXTENDED MEASUREMENT ORDER message that follows in the "n’th message"

field. It is coded as follows:

Value Message

0 0 0 0 0 1 0 1 SYSTEM INFORMATION 5

0 0 0 0 0 1 1 0 SYSTEM INFORMATION 6

0 0 0 0 1 1 0 1 SYSTEM INFORMATION 5bis

0 0 0 0 1 1 1 0 SYSTEM INFORMATION 5ter

0 1 0 0 0 1 1 1 EXTENDED MEASUREMENT ORDER


The "Length of n’th SI message" field indicates in binary the length of the "n’th

message" field that follows.






A-85

XXV. MultiRate Control

This element indicates whether TFO is enabled or not and whether the BSC authorises

the BTS to perform autonomously multi-rate code changes and whether an handover is

to be expected.

It is coded in two octets as follows:

8 7 6 5 4 3 2 1


Spare PRE RAE TFO 3

The TFO field (bit 1 of octet 3) indicates if TFO is enabled or not. It is coded as follows:

Value TFO

0 Tandem Free Operation is enabled

1 Tandem Free Operation is disabled

The RAE field (bits 2-3, octet 3) defines whether the RATSCCH mechanism is enabled

or not. It is coded as follows:

Value RAE

0 0 RATSCCH mechanism is generally enabled, the BTS may change the AMR

configuration within the given SCS and MACS constraints and within the given radio

and Abis channel.

0 1 RATSCCH mechanism will potentially be enabled for one exchange. The BSC

will use a MultiRate CODE MOD REQ message for that purpose

1 0 reserved

1 1 RATSCCH mechanism is generally disabled

The PRE field (bit 4 of octet 3) indicates if an handover is to be expected soon or not. It

is coded as follows:

Value PRE

0 Handover is not expected, respectively has failed

1 Handover is expected soon

XXVI. Supported Code Types

This element indicates the code types supported by the BSS or remote BSS.





A-86

8 7 6 5 4 3 2 1


Length 2

Sys-ID 3

ext Code List 4-n

Preferred Code Type n+1

The Sys-ID field (octet 3) identifies the system that sends or has sent the configuration.

It should be set to 0000 0000 for GSM.

The Code List field (octet 4) lists the code types that are supported by the BSS and

Transcoder, and are therefore potential candidates for TFO establishment. If the

Preferred Code Type is not present (this field is set to “1111.1111”), then the Code List

belongs to the remote BSS, otherwise it is the list of alternative Preferred Code Types.


Bit 1: Set to 1 if the GSM FR Speech Code is supported.

Bit 2: Set to 1 if the GSM HR Speech Code is supported.

Bit 3: Set to 1 if the GSM EFR Speech Code is supported.

Bit 4: Set to 1 if the GSM FR AMR Speech Code is supported.

Bit 5: Set to 1 if the GSM HR AMR Speech Code is supported

Bit 6-7: Reserved, set to 0.

Bit 8: Reserved for extension, set to 0.

If bit 4 of the Code List field (octet 4) indicates that FR AMR is supported or if bit 5 of the

Code List field (octet 4) indicates that HR AMR is supported, the following two octets

(octets 5-6) should be coded as follows:

8 7 6 5 4 3 2 1

Spare TFO_VER MACS 5

SCS 6

If both FR AMR and HR AMR are supported, the octets 5-6 shall be sent twice. The first

occurrence shall correspond to FR AMR configuration, the second one shall

correspond to HR AMR configuration.




A-87

The MACS field (bits 1-2 of octet 5, if present) indicates the Maximum number of AMR

Code ModeS the BSS can support in the Active Code Set. It should be coded as

follows:

0 0: A maximum of four code modes can be supported in the Active Code Set

0.1: A maximum of one code mode can be supported in the Active Code Set

1.0: A maximum of two code modes can be supported in the Active Code Set

1.1: A maximum of three code modes can be supported in the Active Code Set

The TFO_VER field (bits 3-4 of octet 5, if present) indicates the TFO_VERSION.

0 0 : Version 0 of TFO

All other values reserved for future used

The SCS field (octet 6 if present) indicates the Set of AMR Code modes Supported by

the BSS. It should be coded as follows:

Bit 8: Set to 1 if the AMR 12.2 Code Mode is supported.








The Preferred Code Field (bits 1-8, octet n+1) indicates the preferred code type for TFO

establishment. It is coded as follows;

0 0 0 0 . 0 0 0 0: Full Rate Code is preferred

0 0 0 0 . 0.0 0 1: Half Rate Code is preferred

0 0 0 0 . 0 0 1.0: Enhanced Full Rate Code is preferred

0 0 0 0 . 0 0 1.1: FR Adaptive Multi-Rate Code is preferred

0 0 0 0 . 0 1 0 0: HR Adaptive Multi-Rate Code is preferred

1 1 1 1 . 1 1 1 1: No preferred code type

All other values reserved for future used




A-88

XXVII. Frame Number

This element contains the absolute frame number (FN) modulo 42432. It is used to

carry the current timing in BTS to BSC for calculation of the Starting Time parameter

required in some messages.

8 7 6 5 4 3 2 1


T1' T3 (high) 2

T3 (low) T2 3

Octets 2-3 are coded as defined for octets 2-3 of the Starting Time information element

of GSM 04.08.

XXVIII. Cause

The cause element is used to indicate the reason for a particular event to have

occurred and is coded as shown below.

8 7 6 5 4 3 2 1


Length 2

E Cause Value 3

Cause Extension 3a

4

Diagnostic(s) if any

N

The Length field indicates in binary the remaining length of the element (octets 3-N).

The Cause Value is a single octet field (octet 3) if the extension bit E (bit 8) is set to 0. If

it is set to 1 then the cause value is a 2 octet field (octets 3 and 3a).

The Cause Value is divided into two fields: a class (bits 5-7 of octet 3) and a value within

the class (bits 1-4 of octet 3).

If the value of the first octet of the cause field is 1XXX 0000 then the second octet is

reserved for national applications (XXX will still indicate the class).

Diagnostic information is not available for every cause, see the table below. When

available, it is coded in the same way as the corresponding information element in

clause 9. Inclusion of diagnostics is optional.




A-89

Classes:



Class (010): Resource unavailable

Class (011): Service or option not available

Class (100): Service or option not implemented

Class (101): Invalid message (e.g. parameter out of range)

Class (110): Protocol error

Class (111): Interworking

CAUSE VALUES:

Class Value Cause Diagnostics

0 0 0 - - - - Normal Event

0 0 0 0 0 0 0 radio interface failure Channel Number

0 0 0 0 0 0 1 radio link failure Channel Number

0 0 0 0 0 1 0 handover access failure Channel Number

0 0 0 0 0 1 1 talker access failure Channel Number

0 0 0 0 1 0 0 reserved for international use



0 0 0 0 1 1 1 O&M intervention


0 0 0 1 : : :

0 0 0 1 1 1 0

0 0 0 1 1 1 1 normal event, unspecified

0 0 1 - - - - Normal Event


0 0 1 0 : : :

0 0 1 0 1 1 1

0 0 1 1 0 0 0 reserved for national use

0 0 1 1 : : :

0 0 1 1 1 1 1




A-90


0 1 0 - - - - Resource unavailable

0 1 0 0 0 0 0 equipment failure

0 1 0 0 0 0 1 radio resource not available Channel Number

0 1 0 0 0 1 0 terrestrial channel failure Channel Number

0 1 0 0 0 1 1 CCCH overload Channel Number

0 1 0 0 1 0 0 ACCH overload Channel Number

0 1 0 0 1 0 1 processor overload


0 1 0 0 1 1 1 BTS not equipped

0 1 0 1 0 0 0 remote transcoder failure Channel Number

0 1 0 1 0 0 1 notification overflow Channel Number






0 1 0 1 1 1 1 resource not available, unspecified

0 1 1 - - - - Service or Option Not Available

0 1 1 0 0 0 0 requested transcoding/rateadaption not available

Channel Number


0 1 1 : : : :

0 1 1 1 1 1 0

0 1 1 1 1 1 1 service or option not available,unspecified

1 0 0 - - - - Service or Option NotImplemented

1 0 0 0 0 0 0 encryption algorithm notimplemented

Channel Number


1 0 0 0 : : :

1 0 0 0 1 1 1





A-91


1 0 0 1 : : :

1 0 0 1 1 1 0

1 0 0 1 1 1 1 service or option not implemented,unspecified

1 0 1 - - - - Invalid Message

1 0 1 0 0 0 0 radio channel alreadyactivated/allocated

Channel Number


1 0 1 0 : : :

1 0 1 0 1 1 1


1 0 1 1 : : :

1 0 1 1 1 1 0

1 0 1 1 1 1 1 invalid message, unspecified

1 1 0 - - - - Protocol Error

1 1 0 0 0 0 0 message discriminator error Message Discrim

1 1 0 0 0 0 1 message type error Message Type

1 1 0 0 0 1 0 message sequence error Message Type

1 1 0 0 0 1 1 general information element error

1 1 0 0 1 0 0 mandatory information elementerror

Element Identif

1 1 0 0 1 0 1 optional information element error Element Identif

1 1 0 0 1 1 0 information element non-existent Element Identif

1 1 0 0 1 1 1 information element length error Element Identif

1 1 0 1 0 0 0 invalid information element contents Inform. Element







1 1 0 1 1 1 1 protocol error, unspecified

1 1 1 - - - - Interworking




A-92



1 1 1 0 : : :

1 1 1 0 1 1 1


1 1 1 1 : : :

1 1 1 1 1 1 0

1 1 1 1 1 1 1 interworking, unspecified

XXIX. Full Immediate Assign Info

This element is used to convey a full L3 immediate assign message (3 types).

8 7 6 5 4 3 2 1


Length Indicator 2

Full Immediate 3

Assign Info

25

The Length Indicator field (octet 2) indicates in binary the remaining length of the

element (octets 3-25).

The Full Immediate Assign Info field (octets 3-25) contains a complete immediate

assign message (IMMEDIATE ASSIGN or IMMEDIATE ASSIGN EXTENDED or

IMMEDIATE ASSIGN REJECT) as defined in GSM 04.08.

XXX. Link Identifier

This element identifies the signaling channel and SAPI of the radio data link.

8 7 6 5 4 3 2 1


C2 C1 NA priority SAPI 2

The NA bit (bit 6 in octet 2) is set to 1 to indicate that the Link Identifier is not applicable

for this message. In all other cases it is set to 0.




A-93

The C-bits indicate the channel type as follows:

C2 C1

0 0 main signaling channel (FACCH or SDCCH)

0 1 SACCH


The SAPI field contains the SAPI value as defined in GSM 04.05.

The priority field contains the message priority for SAPI 0, as defined in GSM 04.06, as

follows:

0 0 normal priority

0 1 high priority

1 0 low priority

All other values for SAPI 0 and all values for other SAPIs are reserved for future use.

XXXI. RLM Cause

This element is used to indicate the precise protocol error or the reason for a release on

the radio link layer.

8 7 6 5 4 3 2 1


Length 2

E Cause Value 3

The Cause Value is a one octet field if the extension bit is set to 0. If the extension bit is

set to 1, the Cause Value is a two octet field.

The Cause Value field is coded as follows:

8 7 6 5 4 3 2 1

0 0 0 0 0 0 0 0 reserved

0 0 0 0 0 0 0 1 timer T200 expired (N200+1) times

0 0 0 0 0 0 1 0 re-establishment request

0 0 0 0 0 0 1 1 unsolicited UA response

0 0 0 0 0 1 0 0 unsolicited DM response

0 0 0 0 0 1 0 1 unsolicated DM response, multiple frame established state




A-94

0 0 0 0 0 1 1 0 unsolicited supervisory response

0 0 0 0 0 1 1 1 sequence error

0 0 0 0 1 0 0 0 U-frame with incorrect parameters

0 0 0 0 1 0 0 1 S-frame with incorrect parameters

0 0 0 0 1 0 1 0 I-frame with incorrect use of M bit

0 0 0 0 1 0 1 1 I-frame with incorrect length

0 0 0 0 1 1 0 0 frame not implemented

0 0 0 0 1 1 0 1 SABM command, multiple frame established state

0 0 0 0 1 1 1 0 SABM frame with information not allowed in this state


XXXII. L3 Information (message name)

This element contains a link layer service data unit (L3 message). It is used to forward

a complete L3 message as specified in GSM 04.08 between BTS and BSC.

8 7 6 5 4 3 2 1


Length 2

Indicator 3

Link Layer Service Data Unit 4

(i.e. a layer 3 message

as defined in GSM 04.08) n

The Length Indicator field (octets 2-3) indicates in binary the remaining length of the

element (octets 4-n). The most significant bit is bit 8 of octet 2 and the least significant

bit is bit 1 of octet 3.

Octets 4-n contain the complete L3 message as defined in GSM 04.08. In the message

format section, the 04.08 message name to be included is indicated within brackets.




Appendix BDifference between Phase1- Phase2- Phase2+

B-1

Appendix B Difference between Phase1- Phase2-

Phase2+

B.1 Difference between Messages over A-interface inDifferent Phases

The GSM technical specification is a standard constantly improved and perfected. With

the introduction of Phase1, Phase2 and Phase2+, GSM provides different new services

for user to satisfy the requirements from the market. Phase1 of the GSM technicalspecification includes 3.x.x series standard; Phase2 includes 4.x.x series standard, and

the subsequent series standards 5.x.x, 6.x.x and 7.x.x belong to Phase2+. This

technical specification provides good compatibility in the development.

This section gives the development of the A-interface L3 protocol (GSM 08.08) in each

phase. To facilitate description, take the typical protocol in each phase for analysis:

GSM08.08 version 3.10.1 is for Phase1, GSM08.08 version 4.7.1 for Phase2, and

GSM08.08 version 7.6.1 for Phase2+.

B.2 Difference Analysis

I. Message differences in Phase1-Phase2-Phase2+

Table B-1 illustrates the message differences in Phase1/Phase2/Phase2+.

Table B-1 message differences in Phase1/Phase2/Phase2+

Message Phase1 Phase2 Phase2+

AssignmentRequest

Supported

Layer 3 header information

changed as optional IERADIO CHANNEL IDENTITYcancelled, optional IE

CLASSMARK INFORMATION2Reference newly added, optionalIE

Group Call Reference newly

added, optional IE

Talker Flag newly added, optionalIE

LSA Access Control Suppressionnewly added, optional IE

AssignmentComplete

Supported

Radio channel identity cancelled,

Chosen channel Reference newlyadded, optional IE

Chosen encryption algorithm

Reference newly added, optional

Circuit Identity Code newly added,optional IE

Circuit Pool newly added, optionalIE

Speech Version (Chosen) newly





B-2


IE added, optional IE

LSA Identifier newly added,

optional IE

AssignmentFailure

SupportedBasically consistent, with causevalue adjusted


Circuit Pool List newly added,optional IE

Some cause values added

Block(BSC toMSC)supported

(BSC to MSC) supported

Changed as bi-directional(MSC-BSC) messages:

(MSC to BSC) ConnectionRelease Requested Referencenewly added, optional IE

Blocking Acknowledge

Supported Supported Changed to bi-directional

Unblock(BSC toMSC)supported

(BSC to MSC) supported Changed to bi-directional

Unblocking Acknowledge

Supported Supported Changed to bi-directional

Handover Request

Supported

Radio channel identity cancelled,

Cause Reference newly added,optional IE

Classmark information Referencenewly added, optional IE

Current Channel type 1 newlyadded, optional IE

Speech Version (Used) newlyadded, optional IE

Group Call Reference newlyadded, optional IE

Talker Flag newly added, optionalIE

Configuration Evolution Indicationnewly added, optional IE

Chosen Encryption Algorithm

(Serving) newly added, optional IE

Old BSS to New BSS Informationnewly added, optional IE

LSA Information newly added,optional IE

LSA Access Control Suppressionnewly added, optional IE

Handover Required

Supported

Optional IE Cell identifier list(preferred) modified as mandatory

Current radio environment


Current Channel Type 1 newly





B-3


cancelled, optional IE

Environment of BS "n" cancelled,

optional IE

added, optional IE

Speech Version (Used) newly

added, optional IE

Queuing Indicator newly added,optional IE

Old BSS to New BSS Informationnewly added, optional IE

Handover Request Acknowledge

Supported

Layer 3 Information modified incode

Chosen channel Reference newlyadded, optional IE

Chosen encryption algorithmReference newly added, optionalIE


Speech Version (Chosen) newlyadded, optional IE

Circuit Identity Code newly added,optional IE

LSA Identifier newly added,optional IE

Handover Command

SupportedLayer 3 Information modified incode

Cell Identifier newly added,optional IE

Handover Complete

Supported Supported Supported

Handoer Succeeded

Notsupported

Not supported Newly added

Handover CandidateEnquire

SupportedOptional IE Cell identifier modifiedas mandatory

Supported

Handover CanidateResponse

SupportedOptional IE Cell identifier modifiedas mandatory

Supported

Handover Failure

Supported Supported



ResourceRequest

Supported

Optional IE Cell identifier modifiedas mandatory

Extended Resource Indicator Reference newly added, optionalIE

Supported

ResourceIndication

Supported

Resource Indication Methodnewly added, Mandatory IE

Mandatory IE Resource availablemodified as optional

Total Resource accessible newly

added, optional IE

Supported





B-4


Paging Supported

TMSI code changed

Channel Needed newly added,

optional IE

eMLPP Priority newly added,optional IE

Clear Request Supported Supported Supported

Clear Command

SupportedMandatory IE Layer 3 header information modified as optional

Supported

Clear Complete


Reset Supported Supported Supported

Reset Acknowledge

supported Supported Supported

handover Performed

Supported

Optional IE Cell identifier modifiedas mandatory

Optional IE Radio channel identitydeleted

Chosen channel newly added,optional IE

Chosen encryption algorithmnewly added, optional IE

Speech Version (Chosen),optional IE

LSA Identifier newly added

Overload Supported Supported Supported

TraceInvocation

Supported

Modified as 2 messages:

MSC INVOKE TRACE ;

BSS INVOKE TRACE

Modified as 2 messages:

MSC INVOKE TRACE ;

BSS INVOKE TRACE

MSC InvokeTrace

Notsupported

Newly added Supported

BSS InvokeTrace

Notsupported


ClassmarkUpdate

From BSCto MSC

Modified as bi-directional

Change to the optional IEClassmark information type 2

Classmark information type 3newly added, optional IE

Supported

Cipher ModeCommand

Supported

Mandatory IE Layer 3 header information modified as optional

Cipher response mode newlyadded, optional IE

Supported

Cipher ModeComplete

Supported

Layer 3 message contents newlyadded, optional IE

Chosen encryption algorithm

Supported





B-5


newly added, optional IE

Complete

Layer3Information

Supported Chosen channel newly added,optional IE

LSA Identifier List newly added,

optional IE

APDU newly added, optional IE

QueuingIndication


SAPI "n"Reject


SAPI "n"Clear Command

Supported Not supported Not supported

SAPI "n"Clear Complete

Supported Not supported Not supported

handover RequiredReject


Reset Circuit Supported Supported Supported

Reset Circuit Acknowledge


Handover

Detect


Circuit GroupBlock

Notsupported

Newly added (from BSC to MSC) Supported(bi-directional)

Circuit GroupBlocking Acknowledge

Notsupported

Newly added (from MSC to BSC) Supported (bi-directional)

Circuit GroupUnblock

Notsupported

Newly added (from BSC to MSC) Supported (bi-directional)

Circuit GroupUnblock

Acknowledge

Notsupported

Newly added (from MSC to BSC) Supported (bi-directional)

ConfusionNotsupported


ClassmarkRequest

Notsupported


UnequippedCircuit

Notsupported


Cipher ModeReject

Notsupported


Load

Indication

Not

supported Not supported Newly added





B-6


VGCS.CBSSetup

Notsupported


VGVS/VBSSetup ACK

Notsupported


VGCS/VBS AssignmentRequest

Notsupported


VGCS/VBS AssignmentResult

Notsupported


VGCS/VBS AssignmentFailure

Notsupported


VGCS/VBS AssignmentIndication

Notsupported


UplinkRequest

Notsupported


UplinkRequest Acknowledge

Notsupported


UplinkRequestConfirmation

Not

supportedNot supported Newly added

UplinkReleaseIndication

Notsupported


Uplink RejectCommand

Notsupported


UplinkReleaseCommand

Notsupported


Uplink SeizedCommand

Notsupported Not supported Newly added

SuspendNotsupported


ResumeNotsupported


ChangeCircuit

Notsupported


ChangeCircuit Acknowledge

Notsupported






B-7


LSAInformation

Notsupported


LocationInformationCommand

Notsupported


LocationInformationReport

Notsupported


II. message IE difference in Phase1-Phase2-Phase2+Phase1Phase2Phase2

Table B-2 illustrates the IE differences of messages in Phase1/Phase2/Phase2+.

Table B-2 message IE difference in Phase1-Phase2-Phase2+Phase1Phase2Phase2

ELEMENT Phase1 Phase2 Phase2+

Circuit identity code Supported Supported 1544k/s supported

Radio channel identity Supported Deleted Deleted

Resource available Supported Supported Supported

Cause Supported

Directed Retry added

Invalid cell added

Invalid messagecontents added

Information elementor field missing added

Incorrect value added

Unknown Messagetype added

Unknown InformationElement added

Joined group callchannel added

Traffic added

Traffic Load added

Preemption added

Circuit pool mismatchadded

Switch Circuit pooladded

Requested speechversion unavailable

added

LSA not allowed added

VGCS/VBS call nonexistent added

Cell identifier Supported SupportedSupport for PCS1900newly added

Priority Supported PCI domain added Supported

Layer 3 header information Supported Supported Supported

IMSI Supported Supported Supported





B-8


TMSI Supported Supported Supported

Encryption information

Supported (only

A5/1 notencrypted)

Supported (A5/1 A5/2

A5/3 A5/4 A5/5 A5/6 A5/7 not encrypted)

Supported A5/1 A5/2

A5/3 A5/4 A5/5 A5/6 A5/7 not encrypted)

Channel type Supported

Channel rate typenewly added

Full/half ratepreferred, optionalSpeech version 1supported

Data service rateimproved

multi-timeslotassignment supported

Multi-speech versionlike EFR,AMRsupported

Periodicity Supported Parameter strictlydefined

Parameter strictlydefined

Extended resource indicator Not supported Newly addedSM domain newlyadded

Number of MSs Supported Supported Supported

Current radio environment Supported Deleted Deleted

Environment of BS "n" Supported Deleted Deleted

Classmark information type2

SupportedCode of CLASSMARK 2

modified

Supported


Not supported Newly added Supported

Interference band to be used Supported Supported Supported

RR Cause Supported Supported Supported

Trace number Supported Deleted Deleted

Layer 3 information Supported Supported Supported

DLCI Supported Supported Supported

Downlink DTX flag Supported Supported Supported

Cell identifier list Supported SupportedNewly addedPCS1900supported

Response Request Supported Supported Supported

Resource Indication Method Supported Supported Supported



Circuit identity code list Not supported Newly added Supported

Diagnostic Not supported Newly added Supported





B-9


Layer 3 message contents Not supported Newly added Supported

Chosen channel Not supported Newly added

channel mode domain

added

Newly addedmulti-channelsupported

Total resource accessible Not supported Newly added Supported

Cipher response mode Not supported Newly added Supported

Channel needed Not supported Newly addedUnderstanding of 11modified, half/full ratesupported

Trace type Not supported Newly added Supported

Trigger Id Not supported Newly added Supported

Trace reference Not supported Newly added Supported

Transaction Id Not supported Newly added Supported

Mobile identity Not supported Newly added Supported

OMC Id Not supported Newly added Supported

Forward indicator Not supported Newly added Supported

Chosen encryption algorithm Not supported Newly added Supported

Circuit Pool Not supported Not supported Newly added

Circuit Pool List Not supported Not supported Newly added

Time Indication Not supported Not supported Newly added

Resource Situation Not supported Not supported Newly added

Current Channel type 1 Not supported Not supported Newly added

Queuing Indicator Not supported Not supported Newly added

Speech Version Not supported Not supported Newly added

Assignment Requirement Not supported Not supported Newly added

Talker Flag Not supported Not supported Newly added

Connection ReleaseRequested

Not supported Not supported Newly added

Group Call Reference Not supported Not supported Newly added

EMLPP Priority Not supported Not supported Newly added

Configuration EvolutionIndication


Old BSS to New BSS Not supported Not supported Newly added





B-10


Information

LSA Identifier Not supported Not supported Newly added

LSA Identifier List Not supported Not supported Newly added

LSA Information Not supported Not supported Newly added

LCS QoS Not supported Not supported Newly added

LSA access controlsuppression


LCS Priority Not supported Not supported Newly added

Location Type Not supported Not supported Newly added

Location Estimate Not supported Not supported Newly added

Positioning Data Not supported Not supported Newly added

LCS Cause Not supported Not supported Newly added

LCS Client Type Not supported Not supported Newly added

APDU Not supported Not supported Newly added

Network Element Identity Not supported Not supported Newly added

GPS Assistance Data Not supported Not supported Newly added

Deciphering Keys Not supported Not supported Newly added

Return Error Request Not supported Not supported Newly added

Return Error Cause Not supported Not supported Newly added

Segmentation Not supported Not supported Newly added





Signaling Analysis ManualM900/M1800 Base Station Subsystem Appendix C Glossary

C-2

CBS Cell Broadcast Service

CC Call Control

CCCH Common Control Channel

CCH Control channel

CCITT International Telegraph and Telephone Consultative Committee

CCS Common Channel Signaling

CGI Cell Global Identification

CI Cell Identity

CIC Circuit Identification Code

CKSN Circuit Identification Code

CM Connection ManagementCP

CR Connection Request

CRC Cyclic Redundancy Code

CRO Cell Reselect Offset

D

DCCH Dedicated Control CHannel

DCS Digital Cellular System

DLC Data Link Connection

DLCEP Data Link Connection End Point

DLCI Data Link Connection Identifier

DM Disconnected Mode

DPC Destination Point Code

DRX Discontinuous Reception

DTAP Direct Transfer Application Part

DTMF Dual-Tone Multi-frequency

DTX Discontinuous Transmission

E

E3M E3 Sub-Multiplexer

EC Emergency Call

ECSC Early Classmark Sending Control

EFR Enhanced full rate speech codec

eMLPP Environment Monitoring

ETSI European Telecommunications Standards Institute




C-3

F

FACCH Fast Associated Control Channel

FN Frame Number

FR Full Rate

FUC Frame Unit Controller

G

GFBI Fiber Interface board

GMC2 Inter-Module Communication board

GMCC Module Communication and Control board

GOPT Local Optical Interface Board

GPRS General Packet Radio ServiceGPS Global Position System

GSM Global System for Mobile Communications

GSNT GSM Signaling Switching Network Board

GT Global Title

H

HLR Home Location Register

HR Half Rate

HSCSD High Speed Circuit Switched Data

I

ID IDentification/IDentity

IE information element

IMEI International Mobile Equipment Identity

IMSI International Mobile Station Identity

ISDN Integrated Services Digital Network

ISUP Integrated Services Digital Network User Part/ISDN User Part

ITU-T International Telecommunication Union - Telecommunication StandardizationSector

L

L2ML Layer 2 Management Link

LAC Location Area Code

LAI Location Area Identity

LAPD Link Access Procedure on the D channel

LAPDm Link Access Procedure on the Dm channel




C-4

LCS LoCation Service

LPN7 Common Channel Signaling Processing Board

LSA Link State Advertisement

LSB Least Significant Bit

M

MA Mobile Allocation

MACS Maximum number of AMR Codec ModeS

MAP Mobile Application Part

MCC Mobile Country Code

MDC Message Discrimination

MDT Message DistributionME Mobile Equipment

MM Mobility Management

MMCC Mobility Management Call Control

MMSMS Mobility Management Short Message Service

MMSS Mobility Management Supplement Service

MNC Mobile Network Code

MNS Mobile Network Signaling

MOC Mobile Originated Call

MRT Message Routing

MS Mobile Station

MSB. Most Significant Bit

MSC Mobile Switching Center, Mobile Service Switching Center

MSU Message Signaling Unit

MT Maintenance and Test console

MTP Message Transfer Part

N

NA No Acknowledgment

NACK Negative ACKnowledgement

NCC Network Color Code

NECI New Establishment Causes Indication

NI Network Identity

NSS Network SubSystem

O




C-5

OACSU Off Air Call Set Up

OM Operation & Maintenance

OMAP Operation and Maintenance Application Part

OMC Operation and Maintenance Center

OML Operation & Maintenance Link

OPC Originating Point Code

OSI Open System(s) Interconnection

P

PCH Open System(s) Interconnection

PCI Protocol Control Information

PCM Pulse Code ModulationPCS Personal Communications Services

PD Discrimination

PHY Physical Sublayer & Physical Layer

PI cell reselection Parameter Indication

PLMN Public Land Mobile Network

PT Penalty Time

PWRC Power Control

Q

QoS Quality of Service

R

RA Random Access

RACH Random Access CHannel

RAND RANDom number

RF Radio Frequency

RIL3 Radio Interface Layer 3

RLM Radio Link Management

RR Radio Resource

RSL Radio Signaling Link

RXLEV received signal level

RXQUAL received Signal Quality

S

SABM Set Asynchronous Balanced Mode

SACCH Slow Associated Control CHannel




C-6

SAP Service Access Point

SAPI Service Access Point Identification

SCCP Signaling Connection and Control Part

SCMG SCCP Management

SCS Set of AMR Codec modes Supported

SDCCH Stand-alone Dedicated Control Channel

SI Service Indicator

SIM Subscriber Identity Module

SLC Signaling Link Code

SLM Signaling Link Manager

SLS Signaling Link SelectionSLT Signaling Link Test

SM Session Management

SMI Subsequent Modification Indication

SMLC Serving Mobile Location Center

SMS Short Message Service

SNM Signaling Network Management

SRES Signed Response

SRM Signaling Route Management

SS Supplementary Service

SS7 Signaling System No.7

SSN Sub-System Number

STM Signaling Traffic Management

T

TA Timing Advance

TCAP Transaction Capabilities Application Part

TCH Traffic Channel

TCSM Transcoder and Sub-Multiplexer

TDMA Time Division Multiple Access

TEI Terminal Endpoint Identification

TFO Tandem Free Operation

TI Transaction Identifier

TMSI Temp Mobile Subscriber Identifier

TN Time slot Number




C-7

TRX Transceiver

TS technical specification(s)

TUP Telephone User Part

U

UA Unnumbered Acknowledge

UI Unnumbered Information(frame)

V

VBS Voice Broadcast Service

VGCS Voice Group Call Service

VLR Visitor Location Register



Signaling Analysis ManualM900/M1800 Base Station Subsystem Appendix D Abbreviation

D-1

Appendix D Abbreviation

A

ACC Accept

ACK Acknowledgement

ACT Activation

ACTIV Activation

ASS Assignment

AUT Authentication

C

CHAN Channel

CIPH Ciphering

CMD Command

CMP Complete

CNF Confirm

CONF Confirm

CONN Connection

D

DEACT Deactivation

DET Detection

DISC Disconnect

E

ENCR Encryption

EST Establishment

EXT Extended

H

HANDO Handover



Signaling Analysis ManualM900/M1800 Base Station Subsystem Appendix D Abbreviation

D-2

I

IMM Immediate

IND Indication

INFO Information

L

L3 Layer 3

LOC Location

M

MOD Mode

P

PAG Paging

PHY Physical

R

REJ Reject

REL Release

RES Resource

REQ Request

RLSD Released

RPS Response

RQD Required

S

SERV Service

U

UPD Updating



Signaling Analysis ManualM900/M1800 Base Station Subsystem Appendix E Reference for GSM Protocols

E-1

Appendix E Reference for GSM Protocols

Number Short Title

01 series: for GSM system description

01.00 Working Procedures for SMG

01.01 GSM Release 1999 Specifications

01.02 General Description of a GSM Public Land Mobile Network (PLMN)

01.04 Abbreviations and Acronyms

01.31 Fraud Information Gathering System (FIGS); Service requirements - Stage 0

01.33 Lawful Interception requirements for GSM

01.48 ISDN-based DECT/GSM interworking; Feasibility Study

01.56GSM Cordless Telephony System (CTS) (Phase 1); CTS Authentication and Key Generation Algorithms

Requirements

01.60 GPRS requirements

01.61 General Packet Radio Service (GPRS)

02 series: GSM services

02.01 Principles of Telecommunication Services Supported by a GSM Public Land Mobile Network(PLMN)

02.02 Bearer Services (BS) Supported by a GSM Public Land Mobile Network (PLMN)

02.03 Teleservices Supported by a GSM Public Land Mobile Network (PLMN)

02.04 General on Supplementary Services

02.06 Types of Mobile Stations (MS)

02.07 Mobile Station (MS) Features

02.08 European digital cellular telecommunication system (Phase2); Quality of service.

02.09 Security aspects

02.11 Service Accessibility

02.16 International Mobile Station Equipment Identities (IMEI)

02.17 Subscriber Identity Modules, Functional Characteristics




E-2

Number Short Title

02.19 Subscriber Identity Module Application Programming Interface (SIM API); Service description-Stage 1

02.22 Stage 1 for Personalisation of GSM ME

02.24 Description of Charge Advice Information (CAI)

02.30 Man-machine Interface (MMI) of the Mobile Station (MS)

02.31 Fraud Information Gathering System (FIGS) Service description - Stage 1

02.32 Immediate Service Termination (IST); Service description - Stage 1

02.33 Lawful intercept Stage 1

02.34 High Speed Circuit Switched Data (HSCSD) - Stage 1

02.40 Procedures for Call Progress Indications

02.41 Operator Determined Barring

02.42 Network Identity and Time zone (NITZ); Service Description, Stage 1

02.43 Support of Localised Service Area (SoLSA); Service description; Stage 1

02.48 Security mechanisms for the SIM Application Tool kit; Stage 1

02.53 Tandem Free Operation (TFO); Service description; Stage 1

02.56 GSM Cordless Telephony System (CTS), Phase 1; Service description; Stage 1

02.60 General Packet Radio Service Stage 1 Description

02.63 Packet Data on Signalling channels Service (PDS) - Stage 1

02.66 Support of Mobile Number Portability (MNP); Service description; Stage 1

02.67 Enhanced Multi-Level Precedence and Pre-emption Service (eMLPP) - Stage 1

02.68 Voice Group Call Service (VGCS); Stage 1(ASCI spec)

02.69 Voice Broadcast Service (VBS); Stage 1(ASCI spec)

02.71 Location Services (LCS) - Stage 1

02.72 Call Deflection Service description, Stage 1

02.76 Noise Suppression for the AMR

02.78 Customized Applications for Mobile network Enhanced Logic (CAMEL); Service definition (Stage 1)

02.79 Support of Optimal Routeing (SOR); Service definition(Stage 1)




E-3

Number Short Title

02.81 Line Identification Supplementary Services - Stage 1

02.82 Call Forwarding (CF) Supplementary Services - Stage 1

02.83 Call Waiting (CW) and Call Hold (HOLD) Supplementary Services - Stage 1

02.84 MultiParty (MPTY) Supplementary Services - Stage 1

02.85 Closed User Group (CUG) Supplementary Services -Stage 1

02.86 Advice of Charge (AoC) Supplementary Services – Stage1

02.87 User-to-User Signalling (UUS) Service Description, Stage 1

02.88 Call Barring (CB) Supplementary Services - Stage 1

02.90 Stage 1 Decision of Unstructured Supplementary Service Data (USSD)

02.91 Explicit Call Transfer (ECT)

02.93 Completion of Calls to Busy Subscriber (CCBS) Service Description - Stage 1

02.94 Follow Me Service description - Stage 1

02.95Digital cellular telecommunications system (Phase 2+); Support of Private Numbering Plan (SPNP);

Service description, Stage 1

02.96 Name Identification Supplementary Services; Stage 1

02.97 Multiple Subscriber Profile (MSP) Service description, Stage 1

03 services: GSM network

03.01 Network Functions

03.02 Network Architecture

03.03 Numbering, Addressing and Identification

03.04 Signalling requirements relating to routeing of calls to mobile subscribers

03.05 Technical Performance Objectives

03.07 Restoration Procedures

03.08 Organization of Subscriber Data

03.09 Handover Procedures

03.10 Public Land Mobile Network (PLMN) Connection Types

03.11 Technical Realization of Supplementary Services -General Aspects




E-4

Number Short Title

03.12 Location Registration Procedures

03.13 Discontinuous Reception (DRX) in the GSM System

03.14 Support of Dual Tone Multi-Frequency Signalling(DTMF) via the GSM System

03.15 Technical Realization of Operator Determined Barring

03.16 Subscriber Data Management

03.18 Basic Call Handling

03.19 GSM API for SIM toolkit stage 2

03.20 Security-related Network Functions

03.22 Functions related to Mobile Station (MS) in idle mode

03.26 Multiband operation of GSM/DCS 1800 by a single operator

03.30 Radio Network Planning Aspects

03.31 Fraud Information Gathering System (FIGS); Service description - Stage 2

03.32 Universal Geographical Area Description (GAD)

03.33 Lawful Interception - stage 2

03.34 High Speed Circuit Switched Data (HSCSD); Stage 2

03.35 Immediate Service Termination (IST); Stage 2

03.38 Alphabets and Language Specific Information for GSM

03.39Digital Cellular Telecommunications System (Phase 2)Interface Protocols for the Connection of Short

Message, Service Centers (SMSCs) to Short Message Entities(SMEs)

03.40 Technical Realization of the Short Message Service(SMS) Point-to-Point (PP)

03.41 Technical Realization of Short Message Service Cell Broadcast (SMSCB)

03.42 SMS Compression

03.43 Support of Videotext

03.44 Support of Teletext in a Public Land Mobile Network (PLMN)

03.45 Technical realization of facsimile Group 3 service- transparent

03.46 Technical realization of facsimile group 3 service - non-transparent

03.47 Example Protocol Stacks for Interconnecting Service Centre(s) (SC) and Mobile Services Switching




E-5

Number Short Title

Centre(s) (MSC)

03.48 Tool Kit Security Stage 2

03.49Example Protocol Stacks for Interconnecting Cell Broadcast Centre (CBC) and Base Station Controller

(BSC)

03.50Transmission Planning Aspects of the Speech Service in the GSM Public Land Mobile Network (PLMN)

System

03.52 Lower layers of the GSM Cordless Telephony System (CTS) radio interface - Stage 2

03.53 Tandem Free Operation (TFO); Service description, Stage 2

03.54 Description for the use of a Shared Inter Working Function (SIWF) in a GSM PLMN; Stage 2

03.56 GSM Cordless Telephony System (CTS), Phase 1; CTS Architecture Description; Stage 2

03.57 Mobile Station Application Execution Environment (MExE); Functional description; Stage 2

03.58 Characterization, test methods and quality assessment for handsfree Mobile Stations (MSs)

03.60 General Packet Radio Service (GPRS) Service description; Stage 2

03.63 PDS Stage 2

03.64 Overall description of the GPRS radio interface; Stage 2

03.66 Support of GSM Mobile Number Portability (MNP);Stage 2

03.67 Enhanced Multi-Level Precedence and Preemption Service (EMLPP); Stage 2

03.68 Voice Group Call Service (VGCS) - Stage 2

03.69 Voice Broadcast service (VBS) - Stage 2

03.70 Routeing of calls to/from Public Data Network (PDN)

03.71 Location Services (LCS) Stage 2

03.72 Call Deflection stage 2

03.73 Support of Localised Service Area (SoLSA); Stage 2

03.78 CAMEL Phase 2; Stage 2

03.79 Support of Optimal Routeing

03.81 Line Identification Supplementary Services; Stage 2

03.82 Call Forwarding (CF) Supplementary Services; Stage 2




E-6

Number Short Title

03.83 Call Waiting (CW) and Call Hold (HOLD) Supplementary Services; Stage 2

03.84 Multi Party (MPTY) Supplementary Services; Stage 2

03.85 Closed user Group (CUG) Supplementary Services; Stage 2

03.86 Advice of Charge (AoC) Supplementary Services; Stage2

03.87 User-to-user signalling (UUS); Stage 2

03.88 Call Barring (CB) supplementary services - Stage 2

03.90 Unstructured Supplementary Service Data (USSD)

03.91 Explicit Call Transfer (ECT) Supplementary Service; Stage 2

03.93 Technical realization of Completion of Calls to Busy Subscriber (CCBS); Stage 2


03.97 Multiple subscriber Profile (MSP); Stage 2

04 series: MS-BSS Interfaces and specifications (L2 and L3 contexts on interface Um)

04.01 Mobile Station - Base Station System (MS - BSS) Interface General Aspects and Principles

04.02 GSM Public Land Mobile Network (PLMN) Access Reference Configuration

04.03 Mobile Station - Base Station System (MS - BSS) Interface Channel Structures and Access Capabilities

04.04 Layer 1 - General Requirements

04.05 Data Link (DL) Layer General Aspects

04.06 Mobile Station - Base Stations System (MS - BSS) Interface Data Link (DL) Layer Specification

04.07 Mobile Radio Interface Signalling Layer 3 – General Aspects

04.08 Mobile Radio Interface - Layer 3 Specification

04.10 Mobile Radio Interface Layer 3 – Supplementary Services Specification - General Aspects

04.11 Point-to-Point (PP) Short Message Service (SMS) Support on Mobile Radio Interface

04.12 Short Message Service Cell Broadcast (SMSCB) Support on the Mobile Radio Interface

04.13 Performance Requirements on Mobile Radio Interface

04.14 Individual equipment type requirements and interworking; Special conformance testing functions

04.18 Mobile Radio Interface Layer 3 specification; Radio Resource Control Protocol




E-7

Number Short Title

04.21 Rate Adaption on the Mobile Station - Base Station System (MS-BSS) Interface

04.22 Radio Link Protocol for Data and Telematic Services on the MS-BSS Interface

04.30Location Services (LCS); Mobile radio interface layer 3 supplementary services specification; Mobile

Originating Location Request (MO-LR).

04.31Location Services (LCS); Mobile Station (MS) - Serving Mobile Location Centre (SMLC); Radio Resource

LCS Protocol (RRLP)

04.33 Lawful intercept Stage 3

04.35Location Services (LCS); Broadcast Network Assistance for Enhanced Observed Time Difference

(E-OTD) and Global Positioning System (GPS) Positioning Methods

04.53 Inband Tandem Free Operation of Speech codecs, Service Description, stage 3

04.56 GSM Cordless Telephony System (CTS), (Phase 1) CTS Radio Interface Layer 3 Specification

04.57 GSM Cordless Telephony System (CTS), (Phase 1) CTS supervising system Layer 3 Specification

04.60General Packet Radio Service (GPRS); Mobile Station (MS) - Base Station System (BSS) interface;

Radio Link Control/ Medium Access Control (RLC/MAC) protocol

04.63 Packet Data on Signalling channels Service (PDS) Service Description, Stage 3

04.64 Mobile Station - Serving GPRS Support Node (MS-SGSN) Logical Link Control (LLC) Layer Specification

04.65Mobile Station (MS) - Serving GPRS Support Node (SGSN); Subnetwork Dependent Convergence

Protocol (SNDCP)

04.67 Enhanced Multi-Level Precedence and Pre-emption service (eMLPP) - Stage 3

04.68 Group Call Control (GCC) Protocol

04.69 Broadcast Call Control (BCC) Protocol - Stage 3

04.71 Location Services (LCS) Stage 3

04.72 Call Deflection (CD) Supplementary Service; Stage 3

04.80 Mobile Radio Interface Layer 3 – Supplementary Services Specification Formats and Coding

04.81 Line Identification Supplementary Services - Stage 3

04.82 Call Forwarding (CF) Supplementary Services - Stage 3

04.83 Call Waiting (CW) and Call Hold (HOLD) Supplementary Services - Stage 3

04.84 Multi Party (MPTY) Supplementary Services - Stage 3




E-8

Number Short Title

04.85 Closed User Group (CUG) Supplementary Services - Stage 3

04.86 Advice of Charge (AoC) Supplementary Services - Stage3

04.87 User-to-User Signalling (UUS) Supplementary Service Stage 3

04.88 Call Barring (CB) Supplementary Services - Stage 3

04.90 Unstructured Supplementary Service Data (USSD)

04.91 Explicit Call Transfer (ECT) Supplementary Service -Stage 3

04.93 Completion of Calls to Busy Subscriber (CCBS); Stage 3


05 series: physical layer on the radio path (L1 context on interface Um)

05.01 Physical Layer on the Radio Path (General Description)

05.02 Multiplexing and Multiple Access on the Radio Path

05.03 Channel Coding

05.04 Modulation

05.05 Radio Transmission and Reception

05.08 Radio Subsystem Link Control

05.09 Link Adaptation

05.10 Radio Subsystem Synchronization

05.22 Radio Link management in hierarchical networks

05.50 Background for RF Requirements

05.56 CTS-FP Radio Sub-system

06 series: Speech Codec Specifications

06.01 Full Rate Speech Processing Functions

06.02 Half Rate Speech Processing Functions

06.06 Half Rate Speech - Part 7: ANSI-C Code for GSM Half Rate Speech Codec

06.07 Half Rate Speech - Part 8: Test Sequence for GSM Half Rate Speech Codec

06.08 Half Rate Speech; Performance Characterization of the GSM half rate speech codec




E-9

Number Short Title

06.10 Full Rate Speech Transcoding

06.11 Substitution and Muting of Lost Frames for Full Rate Speech Channels

06.12 Comfort Noise Aspects for Full Rate Speech Traffic Channels

06.20 Half Rate Speech Transcoding

06.21 Substitution and Muting of Lost Frames for Half Rate Speech Traffic Channels

06.22 Comfort Noise Aspects for Half Rate Speech Traffic Channels

06.31 Discontinuous Transmission (DTX) for Full Rate Speech Traffic Channels

06.32 Voice Activity Detection (VAD)

06.41 Discontinuous Transmission (DTX) for Half Rate Speech Traffic Channels

06.42 Voice Activity Detection (VAD) for Half Rate Speech Traffic Channels

06.51 Enhanced full rate speech processing functions: General description

06.53 ANSI-C code for the enhanced full rate speech codec

06.54 Test sequences for the GSM Enhanced Full Rate (EFR)

06.55 Performance characterization of the GSM EFR Speech Codec

06.60 Enhanced full rate speech transcoding

06.61 Substitution and muting of lost frames for enhanced full rate speech traffic channels

06.62 Comfort noise aspects for Enhanced Full Rate (EFR) speech traffic channels

06.71 Adaptive Multi-Rate speech processing functions; General description

06.73 ANSI-C code for the GSM Adaptive Multi Rate (AMR) speech codec

06.74 Test sequences for the GSM Adaptive Multi Rate (AMR) speech codec

06.75 AMR performance characterization

06.76 ANSI-C code of the selected AMR-NS algorithm.

06.77 Minimum Performance Requirements for Noise Suppresser Application to the AMR Speech Encoder

06.78 Results of the AMR noise suppression selection phase

06.81 Discontinuous Transmission (DTX) for enhanced full rate speech traffic channels

06.82 Voice Activity Detection (VAD) for enhanced full rate speech traffic channels




E-10

Number Short Title

06.85Subjective tests on the interoperability of the HR/FR/EFR speech codecs; single, tandem and tandem

free operation

06.90 Adaptive Multi-Rate speech transcoding

06.91 Substitution and muting of lost frames for AMR speech traffic channels

06.92 Comfort noise aspects for Adaptive Multi-Rate speech traffic channels

06.93 Discontinuous Transmission (DTX) for Adaptive Multi-Rate speech traffic channels

06.94 Voice Activity Detector (VAD) for Adaptive Multi Rate(AMR) speech traffic channels

07 series: Terminal Adaptation Functions of Mobile Station

07.01 General on Terminal Adaptation Functions (TAF) for Mobile Stations (MS)

07.02 Terminal Adaptation Functions (TAF) for Services Using Asynchronous Bearer Capabilities

07.03 Terminal Adaptation Functions (TAF) for Services Using Synchronous Bearer Capabilities

07.05Use of Data Terminal Equipment - Data Circuit Terminating Equipment (DTE-DCE) Interface for Short

Message Services (SMS) and Cell Broadcast Services(CBS)

07.07 AT Command set for GSM Mobile Equipment

07.08 GSM Application Programming Interface

07.10 Terminal Equipment to Mobile Station (TE-MS) multiplexer protocol

07.60 General Packet Radio Service (GPRS); Mobile Station(MS) supporting GPRS

08 series: BTS-MSC interfaces (A and Abis)

08.01 General Aspects on the BSS-MSC Interface

08.02 Base Station System - Mobile Services Switching Centre(BSS-MSC) Interface - Interface Principles

08.04 Base Station System - Mobile Services Switching Centre (BSS-MSC) Interface Layer 1 Specification

08.06Signalling Transport Mechanism Specification for the Base Station System - Mobile Services Switching

Centre (BSS-MSC) Interface

08.08 Mobile Switching Centre - Base Station system (MSC-BSS) Interface Layer 3 Specification

08.14General Packet Radio Service (GPRS); Base Station System (BSS) - Serving GPRS Support Node

(SGSN) interface; Gb Interface Layer 1


(SGSN) Interface; Network Service




E-11

Number Short Title


(SGSN); BSS GPRS Protocol

08.20 Rate Adaptation on the BSS-MSC Interface

08.31Location Services (LCS); Serving Mobile Location Centre (SMLC) - Serving Mobile Location Centre

(SMLC); SMLC Peer Protocol (SMLCPP) Location Centre (SMLC); Radio Resource LCS Protocol (RRLP)

08.51 Base Station Controller - Base Transceiver Station (BSC-BTS) Interface General Aspects

08.52 Base Station Controller - Base Transceiver Station (BSC-BTS) Interface - Interface Principles

08.54Base Station Controller - Base Transceiver Station (BSC-BTS) Interface Layer 1 Structure of Physical

Circuits

08.56 Base Station Controller - Base Transceiver Station (BSC-BTS) Interface Layer 2 Specification

08.58 Base Station Controller - Base Transceiver Station (BCS-BTS) Interface Layer 3 Specification

08.59 BSC-BTS O&M Signalling Transport

08.60 Inband Control of Remote Transcoders and Rate Adaptors

08.61 Inband Control of Remote Transcoder and Rate Adaptors;(Half Rate)

08.62 Inband Tandem Free Operation (TFO) of Speech Codecs; Service Description; Stage 3

08.71 Location services (LCS) SMLC-BSS interface L3

09 series: Network interworking

09.01 General Network Interworking scenarios

09.02 Mobile Application Part ( MAP) Specification

09.03Signalling Requirements on Interworking between the Integrated Services Digital Network (ISDN), or

Public Switched Telephone Network (PSTN) and the Public Land Mobile Network (PLMN)

09.04 Interworking between the Public Land Mobile Network and the CSPDN

09.05 Interworking between PLMN and PAD access

09.06Interworking between PLMN and a Packet Switched Public Data Network/Integrated Services digital, Network

(PSPDN/ISDN) for Support of Packet Switched Data Transmission Services.

09.07General Requirements on Interworking between the Public Land Mobile Network (PLMN) and the

Intergrated Services Digital Network (ISDN) or Public Switched Telephone Network (PSTN)

09.08 Application of the Base Station System Application Part (BSSAP) on the E-Interface




E-12

Number Short Title

09.09 Detailed Signalling Interworking within the PLMN, with the PSTN/ISDN

09.10

Information Element Mapping between Mobile Station -Base Station System (MS - BSS) and Base

Station System - Mobile-services Switching Centre (BSS - MCS) Signalling Procedures and the Mobile

Application Part(MAP)

09.11 Signalling Interworking for Supplementary Services

09.12 Application of ISUP Version 2 for the ISDN-PLMN (GSM) signalling

09.13Signalling interworking between ISDN supplementary services Application Service Element (ASE) and

Mobile Application Part (MAP) protocols

09.14 Application of ISUP Version 3 for the ISDN-PLMN Signalling

09.16General Packet Radio Service (GPRS); Serving GPRS Support Node (SGSN) - Visitors Location Register

(VLR); Gs interface network service specification

09.18General Packet Radio Service (GPRS); Serving GPRS Support Node (SGSN) - Visitors Location

Register(VLR); Gs interface layer 3 specification

09.31 Location Services (LCS); Base Station System Application Part LCS Extension (BSSAP-LE)

09.60 General Packet Radio Service (GPRS); GPRS Tunnelling Protocol (GPT) across the Gn and Gp Interface

09.61 General Packet Radio Service (GPRS); Interworking between the Public Land Mobile Network (PLMN)supporting GPRS and Packet

09.78 CAMEL Application Part phase 2 (stage 3)

09.90 Interworking between Phase 1 Infrastructure and Phase 2 Mobile Stations (MS)

09.91 Interworking Aspects of the SIM/ME Interface Between Phase 1 and Phase 2

09.94 Recommended Infrastructure Measures to Overcome Specific Phase 1 Mobile Stations Faults

10 series

10.00 Digital Cellular Telecommunication System Feature Description

10.43 Support of Localised Service Area (SoLSA); Work Item Status

10.56 Project scheduling and open issues: GSM Cordless Telephony System CTS, Phase 1

10.57 Project scheduling and open issues: Mobile Station Execution Environment (MExE)

10.59 Project scheduling and open issues for EDGE

10.78 Project scheduling and open issues: CAMEL




E-13

Number Short Title

11 series: specification of equipment and models

11.10-1 Conformance Specification

11.10-2 Mobile Station (MS) Conformance Specification, Part 2 – ICS

11.10-3 Mobile Station (MS) Conformance Specification, Part 3 – Abstract Test suites

11.10-4 SIM Application Toolkit conformance Specification

11.11 Specification of the Subscriber Identity Module - Mobile Equipment (SIM-ME) Interface

11.14 Phase 2+ SIM Application Tool kit

11.17 SIM test specification

11.18 Specification of the 1.8 Volt Subscriber Identity Module - Mobile Equipment (SIM - ME) Interface

11.19 CTS SIM Fixed Part

11.21 GSM Radio Aspects Base Station System Equipment Specification

11.23 GSM Signalling Aspects Base Station System equipment Specification

11.24 GSM transcoding and rate adaptation: Base station

11.26 GSM Repeater Equipment Specification

11.30 Mobile Services Switching Centre

11.31 Home Location Register specification

11.32 Visitor Location Register specification

12 series: O&M

12.00 Objectives and structure of GSM Public Land Mobile Network (PLMN) management

12.01 Common Aspects of Public Land Mobile Network (PLMN) Management

12.02 Subscriber, Mobile Equipment (ME) and Services Data Administration

12.03 Security Management

12.04 Performance Management and Measurements for a GSM Public Land Mobile Network (PLMN)

12.05 Subscriber Related Call and Event Data

12.06 Network Configuration Management and Administration

12.07 Operations and performance management




Documents

Signaling Analysis Manual