BTS30 User Manual

Part 1 System DescriptionTable of Contents i.........................................................................................Chapter 1 An Introduction to BTS30 1-1............................................................

1.1 System Overview 1-1..............................................................................1.2 System Characteristics 1-2.....................................................................

1.2.1 Integrated RF Component Technology 1-2....................................1.2.2 Mature RF Technology 1-2.............................................................1.2.3 Advanced E-Abis Technology 1-2..................................................1.2.4 Powerful O&M Functions 1-3..........................................................

1.3 Application Merits 1-3..............................................................................1.3.1 Wide Coverage 1-3.........................................................................1.3.2 Expenditure Reduction 1-4.............................................................1.3.3 Smooth Evolution 1-4.....................................................................1.3.4 Multiple Transmission Modes 1-4...................................................

1.4 Structure Overview 1-4...........................................................................1.5 Main Functions 1-7..................................................................................

1.5.1 Basic Software Relative Functions 1-8...........................................1.5.2 Basic Hardware Relative Functions 1-8..........................................

1.6 Technical Indices 1-9..............................................................................Chapter 2 Hardware Architecture 2-1.................................................................

2.1 Overview 2-1...........................................................................................2.2 CDU Frame 2-2.......................................................................................

2.2.1 CDU 2-2..........................................................................................2.2.2 EDU 2-3..........................................................................................2.2.3 ECDU 2-4.......................................................................................2.2.4 SCU 2-5..........................................................................................

2.3 TRX Frame 2-5.......................................................................................2.3.1 TRX 2-5..........................................................................................2.3.2 PBU 2-9..........................................................................................

2.4 Common Resource Frame 2-11................................................................2.4.1 PSU 2-11..........................................................................................2.4.2 PMU 2-11..........................................................................................2.4.3 TMU 2-13..........................................................................................2.4.4 TES 2-16...........................................................................................2.4.5 ASU board 2-17................................................................................2.4.6 ABB 2-19..........................................................................................2.4.7 ABA 2-20..........................................................................................

2.5 Other Parts of the Cabinet 2-20................................................................2.5.1 TDU 2-20..........................................................................................2.5.2 FMU 2-26..........................................................................................

2.5.3 Switch Box 2-26................................................................................2.5.4 Fan Box 2-27....................................................................................2.5.5 Air Box 2-27......................................................................................

2.6 Antenna and Feeder System 2-27............................................................2.6.1 Antenna 2-28....................................................................................2.6.2 Feeder 2-29......................................................................................2.6.3 Lightning Arrester 2-29.....................................................................2.6.4 Tower-top Amplifier (Optional) 2-30..................................................

2.7 Power Supply System 2-31.......................................................................2.7.1 Overview 2-31...................................................................................2.7.2 Overall Structure 2-32.......................................................................

2.8 Environment Monitoring System 2-34.......................................................2.8.1 Outlook of Environment Monitoring Instrument 2-34........................2.8.2 Function Provided by Environment Monitoring Instrument 2-35.......2.8.3 Environment Monitoring Instrument Inputs 2-35...............................2.8.4 Alarm Indicators 2-36........................................................................2.8.5 Executing Devices 2-36....................................................................2.8.6 Communication 2-37.........................................................................

2.9 Lightning Protection System 2-37.............................................................2.9.1 Lightning Protection for DC Power Supply 2-38...............................2.9.2 Lightning Protection for AC Power Supply 2-39...............................2.9.3 Lightning Protection for Trunk Cables 2-40......................................

Chapter 3 Software Architecture 3-1..................................................................3.1 Overview 3-1...........................................................................................3.2 Signaling Control Processing (SCP) Program 3-2..................................3.3 Baseband Signal Processing Program 3-4.............................................3.4 Operation and Maintenance Program 3-5...............................................

Chapter 4 External Interfaces 4-1.......................................................................4.1 Abis Interface 4-1....................................................................................

4.1.1 Introduction 4-1...............................................................................4.1.2 Physical Layer 4-6..........................................................................4.1.3 Data Link Layer 4-7........................................................................4.1.4 Layer 3-Traffic Management 4-8....................................................4.1.5 Layer 3-Operation and Maintenance 4-12........................................

4.2 Um Interface 4-14.....................................................................................4.2.1 Introduction 4-14...............................................................................4.2.2 Interface Protocol Model 4-15...........................................................4.2.3 Physical Layer 4-15..........................................................................4.2.4 Data Link Layer 4-19........................................................................4.2.5 Signaling Layer 4-23.........................................................................

Chapter 5 Functions and Performance 5-1........................................................

5.1 Networking Function 5-1.........................................................................5.1.1 E1 Networking 5-1..........................................................................5.1.2 SDH Networking 5-3.......................................................................5.1.3 Networking for Satellite Transmission 5-4......................................

5.2 Main RF Function 5-6..............................................................................5.3 Baseband Processing 5-7.......................................................................

5.3.1 Channel Types Supported 5-8........................................................5.3.2 Channel Combinations Supported 5-8............................................

5.4 Signaling Processing 5-8........................................................................5.5 Operation and Maintenance 5-11..............................................................

5.5.1 Software Loading 5-12......................................................................5.5.2 Abis Interface Management 5-13......................................................5.5.3 Air Interface Management 5-14........................................................5.5.4 Testing Management 5-15................................................................5.5.5 Status Management 5-16.................................................................5.5.6 Processing of Event Reports 5-16....................................................5.5.7 Equipment Management 5-17..........................................................5.5.8 Site Configuration 5-19.....................................................................5.5.9 Tracing Operations 5-19...................................................................5.5.10 Other Functions 5-20......................................................................

5.6 System Indices 5-21..................................................................................5.7 Radio Interface Indices 5-22.....................................................................

5.7.1 Receivers 5-22..................................................................................5.7.2 Transmitters 5-25..............................................................................

Chapter 6 Configuration and Typical Application 6-1.........................................6.1 Configuration 6-1.....................................................................................

6.1.1 Cell Configuration 6-1.....................................................................6.1.2 Configuration of the Common Resource Frame 6-2.......................6.1.3 Configuration of the TRX Frame 6-3...............................................6.1.4 Full Configuration of CDU Frame 6-3.............................................6.1.5 Configuration of the Antenna 6-4....................................................

6.2 Typical Configuration 6-4........................................................................6.2.1 S(2) Configuration 6-4....................................................................6.2.2 S(2/2/2) Configuration 6-5..............................................................6.2.3 O(3) Configuration 6-7....................................................................6.2.4 O(4) Configuration 6-8....................................................................

Appendix A Abbreviations A-1............................................................................

Part 2 BTS Maintenance Terminal SystemTable of Contents i.........................................................................................Chapter 1 Overview 1-1......................................................................................

1.1 Brief Introduction to BTS Terminal Maintenance 1-1..............................1.1.1 BTS Logic Objects 1-1....................................................................1.1.2 Status of BTS Logic Objects 1-1.....................................................

1.2 Brief Introduction to BTS Terminal Maintenance Operations 1-2............1.2.1 User Login 1-2................................................................................1.2.2 Interface Operation 1-3...................................................................

Chapter 2 Site Maintenance 2-1.........................................................................2.1 Overview 2-1...........................................................................................2.2 Site Administrationship 2-1.....................................................................2.3 Start Site Operation 2-3..........................................................................2.4 View Resource 2-4..................................................................................2.5 Force Load SW 2-5.................................................................................2.6 SW Activate 2-6......................................................................................2.7 Site Hierarchical Reset 2-8.....................................................................2.8 Site Test 2-9............................................................................................2.9 Site Environment Monitoring 2-10.............................................................

Chapter 3 Cell Maintenance 3-1.........................................................................3.1 Overview 3-1...........................................................................................3.2 Cell Attributes Management 3-1..............................................................3.3 Cell OpStart 3-5......................................................................................3.4 Change Cell Administrative State 3-5.....................................................3.5 Cell Performance Test 3-6......................................................................

Chapter 4 BT Maintenance 4-1..........................................................................4.1 Overview 4-1...........................................................................................4.2 OpStart BT 4-1........................................................................................4.3 Change BT Administrative State 4-2.......................................................4.4 BT Reinitialization 4-3.............................................................................4.5 BT Test 4-4.............................................................................................

Chapter 5 Channel Maintenance 5-1..................................................................5.1 Overview 5-1...........................................................................................5.2 Channel Attributes Management 5-1......................................................5.3 OpStart Channel 5-3...............................................................................5.4 Change Channel Administrative State 5-3..............................................5.5 Loop Test 5-4..........................................................................................

Chapter 6 RC Maintenance 6-1..........................................................................6.1 Overview 6-1...........................................................................................6.2 RC Attributes Management 6-1...............................................................6.3 OpStart RC 6-2.......................................................................................6.4 Change RC Administrative State 6-3......................................................6.5 RC Reinitialization 6-4.............................................................................

Chapter 7 Board Maintenance 7-1.....................................................................

7.1 Overview 7-1...........................................................................................7.1.1 Board Maintenance Function 7-1....................................................7.1.2 Board Maintenance Operations 7-2................................................

7.2 Board Reset 7-4......................................................................................7.3 OpStart Board 7-5...................................................................................7.4 Board Self-test 7-5..................................................................................7.5 Change Board Administrative State 7-6..................................................7.6 Board Information 7-7.............................................................................7.7 Loop Test 7-7..........................................................................................7.8 Board Alarm 7-8......................................................................................7.9 MCK Clock Operation 7-9.......................................................................7.10 Set MDC Parameters 7-10......................................................................7.11 CDU Operation 7-11...............................................................................

Part 3 BTS MaintenanceTable of Contents i.........................................................................................Chapter 1 Routine Maintenance Instructions 1-1...............................................

1.1 Routine Maintenance Overview 1-1........................................................1.1.1 Purpose of Routine Maintenance 1-1.............................................1.1.2 Routine Maintenance Classification 1-1.........................................1.1.3 BTS Routine Maintenance Record & Instructions 1-2....................

1.2 Weekly Maintenance Instructions 1-8.....................................................1.3 Monthly Maintenance Instructions 1-9....................................................1.4 Quarterly Maintenance Instructions 1-9..................................................1.5 Yearly Maintenance Instructions 1-10.......................................................1.6 Return Loss, VSWR and Reflection Coefficient 1-11................................

Chapter 2 Fault Analysis and Location 2-1.........................................................2.1 Communication Fault 2-1........................................................................

2.1.1 Introduction to Mobile Station’s Search for the Network 2-1...........2.1.2 Call Failure 2-2...............................................................................2.1.3 No Voice Heard after the Call is Connected 2-5.............................2.1.4 Unidirectional Talk 2-6....................................................................2.1.5 Poor Voice Quality 2-7....................................................................2.1.6 Conversation Interruption 2-8.........................................................2.1.7 Cross Talk 2-9................................................................................2.1.8 Mobile Station Frequently Disconnected from the Network 2-9......2.1.9 Immediate Assignment Rejection 2-10.............................................

2.2 Network Fault 2-11....................................................................................2.2.1 Mobile Station Fails to Find a Network 2-11.....................................2.2.2 Mobile Station Fails to Access the Network 2-12.............................2.2.3 MS Frequent Location Updating 2-15...............................................

2.3 Loading Fault 2-16....................................................................................2.3.1 Software Loading Failure 2-16..........................................................2.3.2 Base Station Initialization Failure 2-18.............................................

2.4 Signaling Fault 2-20..................................................................................2.4.1 OML Link Blocked 2-20....................................................................2.4.2 RSL Link Blocked 2-21.....................................................................

2.5 Antenna and Feeder System Fault 2-22...................................................2.6 Optical Channel Fault 2-23.......................................................................2.7 Board Fault 2-24.......................................................................................

2.7.1 CDU 2-24..........................................................................................2.7.2 EDU 2-26..........................................................................................2.7.3 PBU 2-29..........................................................................................2.7.4 PMU 2-31..........................................................................................2.7.5 PSU 2-34..........................................................................................2.7.6 TES 2-36...........................................................................................2.7.7 TEU 2-37..........................................................................................2.7.8 TMU 2-39..........................................................................................2.7.9 TRX 2-42..........................................................................................

HUAWEI

1. System Description

2. BTS Maintenance Terminal System

3. BTS Maintenance

M900/M1800 Base Transceiver Station (BTS30) User Manual

V300R002

M900/M1800 Base Transceiver Station (BTS30)

User Manual

Manual Version T2-030128-20040310-C-4.03

Product Version V300R002

BOM 31013228

Huawei Technologies Co., Ltd. provides customers with comprehensive technical support and service. Please feel free to contact our local office or company headquarters.

Huawei Technologies Co., Ltd.

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

Bantian, Longgang District, Shenzhen, P. R. China

Postal Code: 518129

Website: http://www.huawei.com

Email: [email protected]

Copyright © 2004 Huawei Technologies Co., Ltd.

All Rights Reserved

No part of this manual may be reproduced or transmitted in any form or by any means without prior written consent of Huawei Technologies Co., Ltd.

Trademarks

, HUAWEI, C&C08, EAST8000, HONET, , ViewPoint, INtess, ETS, DMC,

TELLIN, InfoLink, Netkey, Quidway, SYNLOCK, Radium, M900/M1800, TELESIGHT, Quidview, Musa, Airbridge, Tellwin, Inmedia, VRP, DOPRA, iTELLIN, HUAWEI OptiX, C&C08 iNET, NETENGINE, OptiX, iSite, U-SYS, iMUSE, OpenEye, Lansway, SmartAX, infoX, TopEng are trademarks of Huawei Technologies Co., Ltd.

All other trademarks mentioned in this manual are the property of their respective holders.

Notice

The information in this manual is subject to change without notice. Every effort has been made in the preparation of this manual to ensure accuracy of the contents, but all statements, information, and recommendations in this manual do not constitute the warranty of any kind, express or implied.

About This Manual

Release Notes

The product version that corresponds to the manual is M900/M1800 Base Transceiver Station (BTS30) V300R002.

Related Manuals

The following manuals provide more information about the M900/M1800 Base Transceiver Station (BTS30).

Manual Content


It provides an overall introduction to the BTS30, including the software structure, hardware structure, applications, technical specifications and maintenance method.

M900/M1800 Base Transceiver Station (BTS30) Installation Manual

It provides information for the system installation, including the hardware installation and software installation.

Organization of the Manual

M900/M1800 Base Transceiver Station (BTS30) User Manual describes such contents of the BTS30 as the product features, architecture, and working principle of each functional part. It includes 3 volumes and their contents are listed as follows:

System Description gives a general description of the BTS30, including the key features, technical indices, functions, and operation and maintenance structure, and users can get the basic information of BTS30.

BTS Maintenance Terminal System is used to guide users how to operate the local maintenance console. It describes every operation by means of interface, and helps users to get familiar with the routine operation of the BTS30, and learn about its running status.

BTS Maintenance introduced the routine maintenance instructions, faulty analysis and location of BTS30.

Target Readers

The manual is intended for the following readers:

GSM engineers and technicians Telecommunication management staff System engineer of GSM mobile network

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: Means reader be extremely careful during the operation.

Note: Means a complementary description.

Environmental Protection

This product has been designed to comply with the requirements on environmental protection. For the proper storage, use and disposal of this product, national laws and regulations must be observed.

HUAWEI


Part 1 System Description

User Manual M900/M1800 Base Transceiver Station (BTS30)

System DescriptionTable of Contents

i

Table of Contents

Chapter 1 An Introduction to BTS30 ........................................................................................... 1-1 1.1 System Overview............................................................................................................... 1-1 1.2 System Characteristics ...................................................................................................... 1-2

1.2.1 Integrated RF Component Technology................................................................... 1-2 1.2.2 Mature RF Technology............................................................................................ 1-2 1.2.3 Advanced E-Abis Technology................................................................................. 1-2 1.2.4 Powerful O&M Functions ........................................................................................ 1-3

1.3 Application Merits............................................................................................................... 1-3 1.3.1 Wide Coverage........................................................................................................ 1-3 1.3.2 Expenditure Reduction............................................................................................ 1-4 1.3.3 Smooth Evolution .................................................................................................... 1-4 1.3.4 Multiple Transmission Modes.................................................................................. 1-4

1.4 Structure Overview ............................................................................................................ 1-4 1.5 Main Functions................................................................................................................... 1-7

1.5.1 Basic Software Relative Functions.......................................................................... 1-8 1.5.2 Basic Hardware Relative Functions ........................................................................ 1-8

1.6 Technical Indices ............................................................................................................... 1-9

Chapter 2 Hardware Architecture ................................................................................................ 2-1 2.1 Overview ............................................................................................................................ 2-1 2.2 CDU Frame........................................................................................................................ 2-2

2.2.1 CDU......................................................................................................................... 2-2 2.2.2 EDU......................................................................................................................... 2-3 2.2.3 ECDU ...................................................................................................................... 2-4 2.2.4 SCU......................................................................................................................... 2-5

2.3 TRX Frame ........................................................................................................................ 2-5 2.3.1 TRX ......................................................................................................................... 2-5 2.3.2 PBU ......................................................................................................................... 2-9

2.4 Common Resource Frame .............................................................................................. 2-11 2.4.1 PSU ....................................................................................................................... 2-11 2.4.2 PMU ...................................................................................................................... 2-11 2.4.3 TMU....................................................................................................................... 2-13 2.4.4 TES ....................................................................................................................... 2-16 2.4.5 ASU board............................................................................................................. 2-17 2.4.6 ABB ....................................................................................................................... 2-19 2.4.7 ABA ....................................................................................................................... 2-20

2.5 Other Parts of the Cabinet ............................................................................................... 2-20 2.5.1 TDU ....................................................................................................................... 2-20



ii

2.5.2 FMU....................................................................................................................... 2-26 2.5.3 Switch Box............................................................................................................. 2-26 2.5.4 Fan Box ................................................................................................................. 2-27 2.5.5 Air Box................................................................................................................... 2-27

2.6 Antenna and Feeder System........................................................................................... 2-27 2.6.1 Antenna ................................................................................................................. 2-28 2.6.2 Feeder ................................................................................................................... 2-29 2.6.3 Lightning Arrester.................................................................................................. 2-29 2.6.4 Tower-top Amplifier (Optional) .............................................................................. 2-30

2.7 Power Supply System...................................................................................................... 2-31 2.7.1 Overview ............................................................................................................... 2-31 2.7.2 Overall Structure ................................................................................................... 2-32

2.8 Environment Monitoring System...................................................................................... 2-34 2.8.1 Outlook of Environment Monitoring Instrument..................................................... 2-34 2.8.2 Function Provided by Environment Monitoring Instrument ................................... 2-35 2.8.3 Environment Monitoring Instrument Inputs ........................................................... 2-35 2.8.4 Alarm Indicators .................................................................................................... 2-36 2.8.5 Executing Devices................................................................................................. 2-36 2.8.6 Communication ..................................................................................................... 2-37

2.9 Lightning Protection System............................................................................................ 2-37 2.9.1 Lightning Protection for DC Power Supply............................................................ 2-38 2.9.2 Lightning Protection for AC Power Supply............................................................ 2-39 2.9.3 Lightning Protection for Trunk Cables................................................................... 2-40

Chapter 3 Software Architecture ................................................................................................. 3-1 3.1 Overview ............................................................................................................................ 3-1 3.2 Signaling Control Processing (SCP) Program................................................................... 3-2 3.3 Baseband Signal Processing Program.............................................................................. 3-4 3.4 Operation and Maintenance Program ............................................................................... 3-5

Chapter 4 External Interfaces....................................................................................................... 4-1 4.1 Abis Interface..................................................................................................................... 4-1

4.1.1 Introduction.............................................................................................................. 4-1 4.1.2 Physical Layer ......................................................................................................... 4-6 4.1.3 Data Link Layer ....................................................................................................... 4-7 4.1.4 Layer 3 - Traffic Management ................................................................................. 4-8 4.1.5 Layer 3 - Operation and Maintenance .................................................................. 4-12

4.2 Um Interface .................................................................................................................... 4-14 4.2.1 Introduction............................................................................................................ 4-14 4.2.2 Interface Protocol Model ....................................................................................... 4-15 4.2.3 Physical Layer ....................................................................................................... 4-15 4.2.4 Data Link Layer ..................................................................................................... 4-19 4.2.5 Signaling Layer...................................................................................................... 4-23



iii

Chapter 5 Functions and Performance ....................................................................................... 5-1 5.1 Networking Function .......................................................................................................... 5-1

5.1.1 E1 Networking......................................................................................................... 5-1 5.1.2 SDH Networking...................................................................................................... 5-3 5.1.3 Networking for Satellite Transmission..................................................................... 5-4

5.2 Main RF Function............................................................................................................... 5-6 5.3 Baseband Processing........................................................................................................ 5-7

5.3.1 Channel Types Supported ...................................................................................... 5-8 5.3.2 Channel Combinations Supported .......................................................................... 5-8

5.4 Signaling Processing ......................................................................................................... 5-8 5.5 Operation and Maintenance ............................................................................................ 5-11

5.5.1 Software Loading .................................................................................................. 5-12 5.5.2 Abis Interface Management .................................................................................. 5-13 5.5.3 Air Interface Management..................................................................................... 5-14 5.5.4 Testing Management ............................................................................................ 5-15 5.5.5 Status Management .............................................................................................. 5-16 5.5.6 Processing of Event Reports................................................................................. 5-16 5.5.7 Equipment Management ....................................................................................... 5-17 5.5.8 Site Configuration.................................................................................................. 5-19 5.5.9 Tracing Operations................................................................................................ 5-19 5.5.10 Other Functions................................................................................................... 5-20

5.6 System Indices................................................................................................................. 5-21 5.7 Radio Interface Indices .................................................................................................... 5-22

5.7.1 Receivers .............................................................................................................. 5-22 5.7.2 Transmitters .......................................................................................................... 5-25

Chapter 6 Configuration and Typical Application...................................................................... 6-1 6.1 Configuration...................................................................................................................... 6-1

6.1.1 Cell Configuration.................................................................................................... 6-1 6.1.2 Configuration of the Common Resource Frame ..................................................... 6-2 6.1.3 Configuration of the TRX Frame ............................................................................. 6-3 6.1.4 Full Configuration of CDU Frame............................................................................ 6-3 6.1.5 Configuration of the Antenna .................................................................................. 6-4

6.2 Typical Configuration ......................................................................................................... 6-4 6.2.1 S(2) Configuration ................................................................................................... 6-4 6.2.2 S(2/2/2) Configuration ............................................................................................. 6-5 6.2.3 O (3) Configuration.................................................................................................. 6-7 6.2.4 O(4) Configuration................................................................................................... 6-8

Appendix A Abbreviations ...........................................................................................................A-1


System DescriptionChapter 1 An Introduction to BTS30

1-1

Chapter 1 An Introduction to BTS30

1.1 System Overview

In a GSM network, a Base Transceiver Station (BTS) belongs to the radio part of the base station subsystem, i.e. transmitting functions are performed by BTS. Figure 1-1 shows that a BTS is a set of transceiver equipment that serves a certain cell and is controlled by the BSC (base station controller).

MSC: Mobile Switching Center BSC: Base Station Controller SMC: Short Message Center

HLR: Home Location Register BTS: Base Transceiver Station VM: Voice Mailbox AUC: AUthentication Center MS: Mobile Station OMC: Operation/Maintenance Center VLR: Visitor Location Register EIR: Equipment Identify Register

Other MSC/VLR

MAP

M900 BTS

M900 BTS SMC&VMOMC

M900/M1800 BSC

TUP , ISUP

MAP

A interface

MS HLR/AUC/EIR

M900/M1800 MSC/VLR

M1800 BTSM900 BTS

PSTNISDNPSPDN

Um interface

MS

LAN/WAN

Figure 1-1 Position of the BTS in the GSM system

A BTS connects with the BSC via the Abis interface. The air interface (Um interface), is used to realize the radio transmission between the BTS and the MS as well as the associated control functions.

The BTS processes messages on layer 1, layer 2, and non-transparent transmission layer 3 on radio links and performs the related control functions, including:

Interfacing with the BSC Radio channel management Operation and maintenance functions Signaling protocol functions



1-2

1.2 System Characteristics

The M900/M1800 BTS30 is designed as a typical all-in-one BTS by taking full consideration of the requirements of capacity, configuration, installation, power supply, transmission, and services. Its characteristics are as follows.

1.2.1 Integrated RF Component Technology

Expansion based on the inheritance of the investment: BTS expansion can make the utmost of all the antenna and feeder parts.

Modular structure with good performance: RF combiner, divider and low noise amplifier are integrated in CDU (Combining and Distribution Unit). All parts for TRX processing including baseband processing, RF processing, power amplification and power supply are all integrated in one TRX (Transceiver unit). Modular structure can reduce internal cable connections, improve system reliability and facilitate installation and maintenance.

Intelligent CDU: Fine monitor and control function, excellent O&M, level 2 standing wave ratio alarm, low noise amplifier alarm, TTA (Tower Top Amplifier) alarm, TTA power supply. Auto protection against emergency: Close transmission power when transmit path antenna feeder is abnormal; power off to bypass LNA (Low Noise Amplifier) when TTA is abnormal so as to ensure normal system operation. Receive gain can be adjusted via remote control to ensure the sensitivity of the receive system.

1.2.2 Mature RF Technology

RF hopping and baseband frequency hopping are provided to improve system anti-interference capability. It has good performance in practical application.

Advanced digital RF technology is adopted to raise batch consistency, manufacture scalability and stability of the RF system.

1.2.3 Advanced E-Abis Technology

The E-Abis (Enhanced Abis) supports various transmission modes and complex topologies, e.g. SDH, E1, microwave, satellite, etc.

The E-Abis includes the following techniques:

APL (Advanced Phase Locking) technique solves the problem of clock jittery, by using high-precision clock and characteristic software phase lock technique. The problems such as SDH clock phase jittery, signal out of lock during transmission via satellite are solved.



1-3

With a tolerance of up to a bit error rate of 1E-4, i.e. 2 levels higher than the common 1E-6 bit error rate, a better and smooth voice quality can be obtained even in transmission through microwave, and satellite.

The system can tolerate a intermittent link failure of less than 2 seconds, which makes the BTS30 more suitable for applications in unstable conditions such as SDH transmission switching, microwave, satellite transmission etc.

Protection against long transmission delay on the Abis to support satellites networking.

1.2.4 Powerful O&M Functions

BTS30 can perform the following O&M functions: software downloading, BTS object attribute configuration management, equipment management and running status monitoring.

Local end maintenance: provide man machine interface (MMI), and implement maintenance, monitoring and management to all objects of the BTS through the local end maintenance console.

Remote end maintenance: O&M network is made in the GSM system. The authorized user can use any workstation in the network via the remote maintenance console to perform remote O&M to BTS NEs in the system.

System state monitoring provides system running indices indication, resource state indication.

Security management provides MS login authentication, command authority restriction, unsecured operation indication and user group management.

Test: self-test of functions, loop-back test. Upgrade: automatically check the system for upgrade. System upgrading can be

performed via remote loading. The system can be restored to its previous version if system upgrading fails.

1.3 Application Merits

1.3.1 Wide Coverage

When configuring TRX, the nominal value of transmission power at the cabinet feeder port is 40W. When PBU (Power Boost Unit) is equipped, the nominal value of transmission power can reach 80W; When EDU (Enhanced Duplexer Unit) is adopted, the RF signal combining consumption can be reduced and the BTS coverage can be expanded.

Support dual timeslot expansion function (Theoretically, a maximum coverage of 120km can be supported).



1-4

1.3.2 Expenditure Reduction

It supports multiplexing of 15:1, hence greatly reducing transmission expenditure.

Transmission equipment such as SDH is integrated, providing a solution for future upgrade and wideband radio access and reducing transmission equipment investment.

High reliability: Centralized power supply while providing power to various modules in a distributed way. BTS30 and BTS312 can provide DC +24V, DC -48V and AC 220V to satisfy different power supply requirement.

1.3.3 Smooth Evolution

Mixed dual band plug-in of 900MHz and 1800MHz modules of 6 cells. GPRS (General Packet Radio Service), which helps to realize smooth evolution

from 2G to 2.5G.

1.3.4 Multiple Transmission Modes

Multiple built-in transmission modes: 75Ω /E1, 120Ω/E1 and SDH. The BTS has powerful transmission adaptability.

1.4 Structure Overview

I. Logical Structure

In the GSM system, the BTS30 functions as a radio relay, connected with the MS via the Um interface on one side and to the BSC via the Abis interface on the other side.

The logical structure of the BTS30 is shown in Figure 1-2.

TRX

TRX

TRX

CDU

CDU

CDU

FHBUS

TTA TTA

TTA TTA

TTA TTA

PMUPSU

FMU

TDU

TMU

TEU TES

Abis

E1

Fiber(Optinal)

Common Unit Signaling Processor Unit Antenna Feeder Unit

External Alarm

UmCBUS/TBUS/DBUS

BSC

ABB&ABA

Figure 1-2 BTS30 system structure



1-5

As shown in Figure 1-2, the hardware of BTS30 includes the following three functional parts: common unit, carrier unit and antenna unit.

Common Unit

The common unit consists of the Timing/transmission and Management Unit (TMU), the Timing Distribution Unit (TDU), the Transmission Extension Unit (TEU), the Transmission Extension power Supply unit (TES), the Fan Monitor Unit (FMU), the Power Supply Unit (PSU), the Power Monitoring Unit (PMU), the Abis Bypass board (ABB), Abis Bypass Assistant board (ABA), the switch box, the fan box and the air box.

TMU is the basic transmission and control function entity in a BTS30 TDU is installed on the top of the cabinet. TEU is an optional unit used for SDH transmissions. TES is the power supply unit of TEU. FMU within the fan box controls the normal operation of fans and reports alarms

in case of fan failure. PSU is the power supply unit for the whole system. PMU is the power monitoring unit. ABB is the Abis bypass board for the BTS30 in the chain networking. ABA is the Abis bypass assistant board. Switch box: distributed power supply is adopted to improve the reliability of

power supply. Fan box: FMU is installed within the fan box. Air box is the inlet for the cool air. It is part of the cooling system to guarantee

the normal operation of BTS.

Signaling Processor Unit

The signaling processor unit comprises Transceiver (TRX) unit, Power Booster Unit (PBU), Combiner and Divider Unit (CDU), Enhanced Duplexer Unit (EDU) and Simple Combiner Unit (SCU).

TRX is a software and hardware entity that performs all processing functions of one carrier.

PBU is the output power booster of TRX. It also provides the function of alarm collection.

CDU supports broadband hybrid combining. At the transmitting end, signals of 2 channels are combined into 1 (2-into-1), while at the receiving end signals from 2 channels are divided into 4 (or 8 in case of only one channel) channels.

EDU is a low-loss duplex divider unit which can achieve the transmitting and diversity receiving of signals for two TRXs.

SCU fulfills 4-into-1 combining. It is used to save CDUs.

Antenna Feeder unit



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Antenna feeder unit implements the receiving and transmitting of RF signals. It includes the antenna, feeder, low-loss transmission cable and lightning arrester.

II. Software structure

BTS software not only performs the protocol functions specified in the signaling model shown in Figure 1-3, but also implements BTS operation, maintenance and testing functions.

Based on different hardware entities, BTS software consists of:

Radio interface signal processing unit, i.e., the Um interface media access layer running in the digital signal processing unit of the TRX module,

Signaling processing unit, including radio resources management (RR), Abis interface link layer protocol (LAPD), Abis interface media access control layer, Um interface link layer protocol (LAPDm), etc. which run in the signaling processing unit of TRX module,

Operation and maintenance unit, including BTS fault management, performance management, configuration management, security management, data management, Abis interface transmission control and local man-machine interface, which run in the TMU unit.

BTS software also includes the programs handling the communication among various units in BTS.

CM

MM

RR

LAPDm

SigL1

MS

L3

L2

L1

RR

LAPDm

SigL1

BTSM

LAPDm

SigL1

BTS

BTSM

LAPDm

SigL1

RR BSSMAP

SCCP

MTP

BSC

CM: Connection Management LAPD: Link Access Protocol on D channel MM: Mobility Management LAPDm: Link Access Protocol on Dm channel RR: Radio Resource Management SCCP: Signaling Connection Control Part BTSM: BTS Management MTP: Message Transfer Part BSSAP: Base Station Subsystem Application Part

Figure 1-3 BTS signaling structure

III. Cabinet structure

1) Dimension



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The cabinet of the M900/M1800 BTS30 is a 19 inch standard cabinet in accordance with the IEC297 standard, with the following dimensions:

Height×Width×Depth=1600mm ×600mm×450mm.

The cabinet is shown in Figure 1-4.

(1)

(2)

(3)

(4)

(5)

(6)

(7)

(8)

(1) TRX/CDU frame (2) Rack (3) Common resource frame (4) Switch box (5) Fan box (6) Air box (7) Front door (8) Back plate

Figure 1-4 General view of the cabinet

2) Cabinet features Standard 19" cabinet. Strong and simple structure. Aluminum alloys are used to reduce the cabinet's weight. Good shielding effect and conductivity. Wind tunnels ensure good ventilation and heat dissipation. Simple and convenient installation and maintenance.

1.5 Main Functions

Basic functions provided by BTS30 software and hardware are listed below.



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1.5.1 Basic Software Relative Functions

The BTS30 has the following main functions:

Support both 900MHz and 1800MHz frequency systems. Support EGSM/RGSM extended frequency band services. All data services prescribed in Phase II+. Support GPRS. Support Phase I/Phase II /Phase II+ compatible LAPDm protocol. Support Phase I/Phase II/Phase II+ compatible system message issuing and

resources instruction. Support CS-1/CS-2/CS-3/CS-4 radio channel coding scheme. Support FR (Full Rate) / EFR (Enhanced Full Rate) / HR (Half Rate) and all

kinds of speech coding scheme. Support broadcast short message and point-to-point short message. Support paging queue. Support A5/1, A5/2 encryption/decryption. Support basic data dynamic configuration. Support basic data dynamic configuration. Support measurement report preprocessing. Support Abis,10:1, 12:1 and 15:1signaling multiplexing. Support BCCH carrier cooperation. Support immediate assignment combination and paging combination, boosting

the radio channel efficiency. Support discontinuous transmission (DTX) and DRX. Support omni cell and directional cell. Support chain/tree/start/loop networking. Support locked, fast pull-in, holdover and free run clock modes. Support synchronous, asynchronous and quasi-synchronous handover. Support Um interface tracing and internal interface tracing. Support remote and local loading of software. Support dynamic and static power control. Support satellite transmission and Abis 16k signaling transmission. Support extended cell. Support scanning uplink frequency band. Support Huawei’s G-II power control algorithm. Support multi-cell (up to 12 cells) configuration. Support timeslot based baseband/RF frequency hopping. Support Class3 MS large power.

1.5.2 Basic Hardware Relative Functions

Support eight E1s and 12 antenna feeders. Support built-in optical transmission boards TEU and TES.


System Description Chapter 1 An Introduction to BTS30

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Support 24 switching/digital inputs, 8 digital outputs and 8 analog inputs. Support cabinet combination. Support storage battery management. Support both M900 and M1800 modules. Support lightning protection at trunk ports, power supply ports and RF ports. Support E1 bypass after BTS power failure Support PBU (Power Boost Unit) and EDU (Enhanced Duplexer Unit). Support monitoring external power. The power monitoring module reports the

alarm when there is no power input. Support the report of BTS bar code, software version and hardware version of

part of the boards Support TMU self-correcting crystal oscillation central frequency. Support clock backup and master/slave clock handover. Support clock pull-in mode. Support E1/RF self-loop test.

1.6 Technical Indices

Physical dimensions

Height×Width×Depth=1600mm×600mm×450mm

Power system

220V AC: 150~280VAC/45~65Hz

-48V DC: -40~-60VDC

24V DC: 19~29VDC

Working temperature

-5ÿC ~ +45ÿC (ambient temperature)

Working humidity

15% ~ 85%

Weight

180kg for a single cabinet when fully configured

Weight bearing requirement: 250kg/m2 (with 10% tolerance)

Power consumption

Maximum power consumption of a single cabinet: 1200W

Receiving sensitivity

-110dBm (GSM900), -109dBm (GSM1800)

Transmitting power

TRX output power: 40W (46 dBm) or 60W (47.8 dBm)



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TRX (40W) + PBU output power: 80W (49 dBm)


System DescriptionChapter 2 Hardware Architecture

2-1

Chapter 2 Hardware Architecture

2.1 Overview

A BTS30 cabinet mainly comprises a common resource frame, a TRX frame and a CDU frame, which can be flexibly configured according to the user demands. There are also some other elements like TDU, switch box, fan box, air box, etc.

The hardware architecture of the BTS30 cabinet is shown in Figure 2-1.

CDU CDU CDU

SWITCH BOX

TX

RX

TRX

TX

RX

TRX

TX

RX

TRX

TX

RX

TRX

TX

RX

TRX

TX

RX

TRX

P

S

U

P

S

U

P

S

U

P

S

U

P

M

U

T

M

U

T

M

U

T

U

E

T

E

S

AIR BOX

FAN BOX

TDU

CDU: Combiner and Divider Unit TRX: Transceiver Unit PMU: Power Monitoring Unit TMU: Timing/Transmission and Management Unit PSU: Power Supply Unit TES: Transmission Extension Power Supply Unit TEU: Transmission Extension Unit TDU: Timing Distribution Unit

Figure 2-1 Hardware architecture of the BTS30 cabinet



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2.2 CDU Frame

The CDU frame implements the combining of transmitted signals, dividing of received signals and duplex functions. The frame can be configured with CDU, EDU or SCU.

2.2.1 CDU

I. General

CDU combines and filters the transmitted signals, filters, amplifies and distributes received signals. It also provides feed circuit for the tower-top amplifier through a bias-T circuit.

Through bridge combing (broadband combing) used in BTS30, multiple TX and RX signals can be multiplexed on a single antenna unit.

The 2 channels of transmitting signals are combined into 1 (2-into-1), while at the receiving end signals from 1 of the 2 channels are divided into 4 (or 8 incase of only one channel) channels.

Each CDU provides a diversity receiving branch.

II. Structure and function

The functional blocks of the CDU are shown in Figure 2-2.

Test coupler Amp. feeder

Divider

Duplexer

LNA Rx filter

Alarm and control unit

Combiner

Tx signal input

Rx signal output

Divider

Rx signal output

LNA

Amp. feeder

CDU

Figure 2-2 Functional blocks of the CDU

Besides the combining and dividing functions, CDU also has the following alarm detection functions:

VSWR (Voltage Standing Wave Ratio) monitoring: Monitoring the status of antenna system. When the detected VSWR exceeds the threshold 1.5:1, the CDU reports minor alarm and the corresponding indicator on the panel is on. When the VSWR exceeds the threshold 2.5:1, the CDU reports critical alarm, the



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corresponding indicator on the panel is on, and signal transmission will stop 1 minute later.

Low noise amplifier fault alarm: The fault signal is extracted from the power supply current of the low noise amplifier. When the current exceeds a certain level, alarm signals and indications are generated.

Tower-top amplifier alarm: When there is tower-top amplifier in service, the CDU determines the operation status of the amplifier according to its working current. If the current exceeds preset value or there is no current, alarm signal will be generated.

Control functions: Remotely control the low noise amplifier attenuation (dynamic control 15 levels, in steps of 1dB) both in the main receiving path and diversity receiving path, supply/cut the feeder depends on whether tower-top amplifier is equipped, cut the feeder to the amplifier in case of alarm.

Note:

The input power of the CDU configured in BTS30 is 60W. When PBU is used, ECDU with large power should be configured.

2.2.2 EDU

I. General

EDU is a low-loss duplex and dividing unit aimed to solve the issue of wide coverage. It can perform the duplex function for two TRXs, the filtering of transmitted/received signals, low noise amplification, and dividing function. It also provides feeder to the tower-top amplifier.

Each TRX uses its own antenna, so no combination of signals is needed. For received signals, 1-to-2 dividing is employed.


The functional blocks of the EDU are shown in Figure 2-3.



2-4

EDUTest coupler Amp. feeder

Divider

Duplexer

LNAAlarm and control unit

Tx signal input

Rx signal output

DividerRx signal output

LNA

Amp. feederTx signal input Duplexer Test coupler

Figure 2-3 Functional blocks of the EDU

Besides the combining and dividing functions, the EDU also provides the following alarm detection functions:

1) VSWR (Voltage Standing Wave Ratio) monitoring: Monitoring the status of the antenna system. When the VSWR exceeds the threshold 2.5:1, the EDU reports alarm.

2) Low noise amplifier fault alarm: The status of the LNA can be determined based on the power supply current. When the current exceeds a certain level, alarm signals and indications are generated.

3) Tower-top amplifier alarm: When there is tower-top amplifier in service, EDU determines the operation status of the amplifier according to the working current of amplifier. If the current exceeds preset value or there is no current, alarm signal will be generated.

4) Control functions: Remotely control the low noise amplifier attenuation (dynamic control 15 levels, in steps of 1dB) both in the main receiving path and diversity receiving path, supply/cut feeder depends on whether tower-top amplifier is equipped, cut the feeder to the amplifier in case of alarm.

2.2.3 ECDU

The functions and external interfaces (including dimensions) of ECDU are the same as that of CDU. It implements combination of transmitted signals, dividing of received signals, and duplex functions. The difference is that the maximum power input of ECDU reaches 100W.



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2.2.4 SCU

I. General

SCU combines the signals from 4 TRXs into 1 channel for transmission. It employs the electric bridge with 3dB power loss to achieve the broadband combing. Used together with CDU, it can achieve the combination of signals from multiple TRXs. The introduction of SCU is to reduce the number of CDUs, hence saving costs.


The functional blocks of the SCU are shown in Figure 2-4.

SCU1

2

3

4

Combiner

Tx signal input

Combiner

Tx signal outputCombiner

Figure 2-4 Functional blocks of the SCU

2.3 TRX Frame

The TRX frame implements all the processing functions of the carrier, including baseband processing, RF processing, power amplifier and power supply. The TRX frame can be configured with the TRX and the PBU.

2.3.1 TRX

I. General

TRX is the key part of the BTS which receives various types of management and configuration information issued by the TMU and reports its status and alarm information to the TMU.

The TRX separates the received information from the mobile stations through demodulation and balancing into signaling and speech information, and transmits them upward (i.e. to BSC and MSC). The downlink signaling and speech information is sent to the CDU and the antenna after being processed by the TRX.



2-6

With a modular structure, the TRX module contains both the baseband processing unit, and the radio frequency unit.

II. Structure and functions

The structure of the TRX unit is shown in Figure 2-5. It includes the baseband signal processing unit (TBU) and the radio frequency signal processing unit (RPU).

SCP DSP CUITDP PAU

RCU

TBU RPU

DBUS FH _BUS

CBUS

TIMING_BUS

Clock processing part

Send

Main receiverDiversity receiver

SCP: Signaling Processing Unit DSP: Digital Signal Processing Unit CUI: Carrier Unit Interface PAU: Power Amplifier Unit RCU: Receiving Unit TDP: Transmitter Driver and PLL unit TBPU: TRX Baseband signal Processing Unit RPU: RF signal Processing Unit CBUS: Control Bus FH_BUS: Frequency Hopping Bus DBUS: Data Bus

Figure 2-5 Structure of the TRX unit

1) Baseband signal processing unit (TBU)

The TBU consists mainly of the Signaling Processing Unit (SCP), the Digital Signal Processing unit (DSP), and the Carrier Unit Interface (CUI). As the GSM system is a time division multiplexing system, the operation of the TRX relies on various clocks. So the TRX contains some clock processing logical units.

Signaling processing unit (SCP)

The SCP processes signaling protocols on different BTS interfaces, including the layer 2 protocol LAPDm with the mobile station (MS), the layer 2 protocol LAPD with the BSC interface, and the layer 2 protocol (DCL) with the operation & maintenance module (OMU), as well as layer 3 non-transparent messages.

The SCP also handles DSP program loading and alarm processing of the whole TRX module.

Digital signal processing unit (DSP)



2-7

The DSP performs such functions as signal encoding/decoding, signal demodulation, interleaving and de-interleaving, and speech/data communication with the TRAU.

It sends the signaling received from the MS to the SCP, receives signaling sent from the SCP, and performs corresponding encoding/decoding according to related protocols. It sends the downlink data via the CUI to the carrier unit RPU.

Carrier unit interface (CUI)

The CUI is the interface between the DSP and the RPU. It supports baseband hopping, and according to system configuration can work in either hopping or non-hopping mode (when the system works in the RF hopping mode, the hopping interface works in non-hopping mode and the hopping functions are completed by the carrier unit).

The CUI samples and filters the uplink intermediate frequency signals sent from the RPU, and sends them to the DSP for demodulation and combination.

Clock processing part

The TRX extracts clocks sent from the TMU over the clock buses. To ensure the reliability, the clock buses work in active/standby mode. These clocks include the frame clock, the octet bit clock, and the frame number.

The clock processing part in the TRX first chooses either the active clock or the standby clock, then makes frequency division calculation and generates the timeslot number and bit clocks required by the local TRX.

2) Radio frequency signal processing unit (RPU)

The RPU consists of 3 parts: Receiving Unit (RCU), Transmitter Driver and PLL unit (TDP), and Power Amplification Unit (PAU).

Receiving unit (RCU)

The RCU provides diversity reception functions, that is, the receiver consists of two completely independent channels, and the input signals come from the main antenna and diversity antenna. In complicated radio transmission areas where one antenna receives very poor signal, the signal received from the other (diversity) antenna may be of a better quality.

The BTS receives signals from both the main channel and the diversity channel, then handles demodulation after combination algorithms. It can provide 3~5dB diversity gain, thus improving the communication quality.

Each receiving channel consists of down conversion circuits. The received signals are sent to the frequency mixer after filtering and amplification, so as to generate intermediate frequency signals, which after further filtering and amplification are directly sent to the baseband unit for digital demodulation processing.



2-8

Transmitter Driver and PLL unit (TDP)

This unit consists of 3 parts, transmitter excitation, frequency synthesizer, and PLL testing.

Transmitter excitation unit directly modulates the I and Q signals sent from the baseband unit through the orthogonal modulator into the radio signals for transmission. This works rather simple and reliable.

After modulation, the signal controlled by the APC provides the power amplifier unit (PAU) with a certain power level.

The transmitter excitation unit also provides the dynamic and static power control at the base station. Static power control (the maximum transmission power of the base station) is specified during network planning. In contrast, dynamic power control is performed during communication. Static power control has 0~10 levels (level 0 is 46dBm), decrementing by 2dBm each level. Dynamic power control has 0~15 levels, decrementing by 2dBm each level.

To reduce noise in the radio environment and improves the network capacity and service quality, the base station transmission power should be kept as low as possible as long as the communication quality can be ensured. So each traffic channel is kept at the lowest possible dynamic power level, with all idle channels transmission shut down.

Moreover, transmitter excitation also provides the over-power alarm signal and under-power alarm signal of the TRX. When the TRX output power is 3dB higher than the specified level, over-power alarm will be generated. When the TRX output power is 3dB lower than the specified level, under-power alarm will be generated.

Frequency synthesizer is the essential part of the whole transceiver. It generates various local oscillation for the up/down frequency conversions, such as transmitter local oscillation, receiver local oscillation, and PLL test local oscillation. Each of the transmitter local oscillation and receiver local oscillation has two loops to achieve hopping loop switchover.

PLL testing is designed for TRX loopback testing. It attenuates part of the signals coupled by the power amplifier output into the receiving frequency band through frequency conversion, then sends them to the receiver after coupling. It is used to check the TRX transmit channel and the receive channel.

Power amplifier unit (PAU)

The PAU mainly performs radio signal amplification. Its maximum output power level can be 46dBm or 47.8dBm. It also provides feed sampling signals controlled by the transmitter APC, and the following alarm information:



2-9

Over-temperature alarm, when the temperature of the power amplifier exceeds 85C, the power amplifier unit reports the high-temperature alarm via the baseband unit, and automatically turns off the power amplifier.

Over standing wave alarm, when the standing wave at the power amplifier output end exceeds 3.5, it reports standing wave alarm to the baseband unit.

III. Interface

External interfaces of the TRX module includes:

CBUS2: the interface between the TRX and the TMU. The TMU performs management and maintenance on the TRX module through the CBUS.

DBUS1, DBUS2: the switching functions of TMU switch the DBUS of the TRX to the Abis interface. The uplink and downlink signaling processed by the SCP and the uplink and downlink speech data processed by the DSP are all transmitted through the DBUS.

TIMING_BUS: it receives the frame clock and 1/8-bit clock as well as frame number of the TDU, and obtains the various clock signals required by the TBU board through the clock unit interface.

FH_BUS: used to transmit hopping data between TRX modules when the BTS is in the baseband hopping mode.

Radio interface: the TRX radio interface has 1 transmit terminal and 2 receive terminals. The function of the 2 receive terminals is the main reception and diversity reception. The TRX radio interfaces are connected to the CDU.

Panel display: on the panel, there are 4 LED indicators, from top to bottom they are power supply indicator, SCP running indicator, DSP running indicator, and fault indicator.

IV. Indices

Power supply: +26V DC.

Average power consumption: 150W approximately.

2.3.2 PBU

I. General

The Power Booster Unit (PBU) is a kind of TRX output power amplifier aimed to solve the problem of wide coverage. It can enhance the Effective Radiation Power (ERP) of the antenna and enlarge the coverage area of a BTS. The maximum output power of the PBU reaches 49±1dBm.



2-10

The PBU comprises the power synthesizer module, the alarm management module and the power supply module. It can amplify the output power of 1 TRX.

II. Structure and functions

The functional blocks of the PBU are shown in Figure 2-6.

Input coupling & delay filtering

Amp. & phase control 60W power amplify

Power Synthesizer Module

Alarm collect & outputControl signal generation

Alarm Management Module

26V

26V

±À8V

±8V

Alarm collectionPower amplify control

Alarm output

26V

TRX power output

PBU

CoupleOutput

PBU poweroutput

Powe

r mod

ule

Powe

r syn

thesiz

e an

d dete

ct

Figure 2-6 Functional blocks of PBU

The PBU couples the 40W power signals output from the TRX into main channel signals and coupled channel signals. The main channel signals, after delay filtering, enter the power synthesizer unit. The coupled channel signals are amplified into 60W signals before being sent to the power synthesizer unit. To obtain final combined signals, amplitude and phase control will be conducted on the 2 channels of input signals.

The generation of control signals and the collecting/reporting of alarms are completed by the alarm management module. While the coupling, controlling and synthesizing of power signals are performed by the power synthesizer module.

1) Power synthesizer module

Under the control of alarm management module, the power synthesizer module amplifies TRX output signals, and at the same time provides power control and alarm information, and alarm signals to the alarm management module, which detects power amplification functionality and reports alarms.

2) Alarm management module

The alarm management module receives from the power synthesizer module the power control and alarm information, and alarm signals. It is responsible for the detection of power amplification functionality and the control over amplitude and phase. It also reports relevant alarms.



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3) Power supply module

The power supply module supplies power to the power synthesizer module and the alarm management module.

2.4 Common Resource Frame

The common resource frame is the most import part of the cabinet. It includes 14 slots. Except for slots No.8 and No.9 which are reserved, other slots are respectively configured (from left to right) with PSUs (6 slots), PMU, TMU, TES and TEU. Configurations of the TES and the TEU are optional.

2.4.1 PSU

PSU is a built in power supply module.

Depending on the power supply mode, BTS30 uses the power supply module of different models. When 220VAC is adopted, the BTS uses the power supply module with 220VAC input and +26VDC output. When +48VDC is adopted, it uses the module with +48VDC input and +26VDC output. When +24VDC is used, no power supply module is needed.

One PCU can supply power to two TRXs in N+1 flow-equalization hot-standby mode. The working current of the module is 25A.

Note:

For detailed descriptions, please refer to section 2.7 Power Supply System.

2.4.2 PMU

I. General

PMU (Power Monitoring Unit) is close to the power supply module, managing the power supply of the module. There are two types of PMUs: PMU for the DC/DC module and PMU for the AC/DC module. The main difference between these two is the battery management function. To reduce work load, both the AC/DC module and the DC/DC module share one monitoring board.

II. Functions

Following describes the AC/DC module monitoring board.



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1) Control Switch on/off of the power module (remote control available), with an output

signal of 12V/10mA Floating/equalizing charge of battery and current limit control Connect/disconnect control of battery protection load, with a 23±0.5V output

low-voltage alarm, loading power-on/off condition 2) Switch signals

AC mains on/off signal and high-/low-voltage signal (12V/10mA) Four fault status parameters (12V/10mA) provided to the monitoring board by 4

AC/DC modules Fan monitoring status parameters (normally, 12V/10mA) Fuse on/off status parameters of external battery (-0.3V<normal voltage

difference <0.3V) 3) Current and voltage analog signals

Battery group current (A) Total load current (A) Busbar voltage (V)

4) Panel design

PMU normal running indicator RUN: A green indicator flashes once per 500ms when the monitoring module runs normally, it remains off or on when the system monitoring module does not work).

System fault alarm indicator ALM: 1 red indicator.

5) Description of interface setting

The monitoring board provides one RS485 port to report monitoring information to TMU.

The illustration of the monitoring by the PMU is shown in Figure 2-7.

Fan PMU

AC power supply

AC/DC AC/DC ... AC/DC

Fuse

Battery

Load

Figure 2-7 Illustration of the PMU monitoring



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2.4.3 TMU

I. General

TMU is located in the common frame of the BTS30. It is the timing, transmission and management function entity of BTS30. It has the following main functions:

Provides channel multiplexing and flexible networking modes (including star-, tree-, and chain- connections).

Provides Man-Machine Interfaces (MMI) and operation & maintenance links for software loading, fault management, configuration management, performance management and security management, etc.

Provides centralized BTS clock and its management, and clock hot standby function.

Provides alarm signal input ports, and handles external alarm collection and control.

Two TMUs can be configured in the basic cabinet, providing clock source in hot standby mode and serving to increase the number of E1 interfaces (each TMU provides 4 E1 interfaces). In combined cabinet configurations, TMU boards are configured in the basic cabinet only.

II. Structure and working principle

The functional blocks of the TMU are shown in Figure 2-8.

MCK

OMU

BIU

EAC

DBUS

CBUSMMI

BSC

MCK

Active TMU

Environment Monitors

Abis

TDU

Standby TMU

BIU

TBUS

Maintenance Terminal

RS485

External clock

BSC: Base Station Control TMU: Timing/Transmission and Management Unit BIU: Base Station Interface Unit OMU: Operation and Maintenance Unit EAC: External Alarm Collector MCK: Main Clock module TBUS: Timing Bus DBUS Data Bus CBUS: Control Bus TDU: Timing Distribution Unit

Figure 2-8 Functional blocks of the TMU



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1) Base station interface unit (BIU)

The BIU handles conversion and reconversion between digital signals of the BTS’ internal HWs and the HDB3 codes (on E1 lines). It switches timeslots on HW to achieve flexible timeslot configuration, extracts superior clock signals, supports external clock input, and outputs accurate clock signals through phase locking and frequency division. It synchronizes internal bus data transmission, or generates free-run clock signals when superior clocks are not available (due to E1 line or BSC fault) to synchronize internal bus data transmission, and generates alarm and reports them to OMU.

One BIU module can support a maximum of 4 E1 lines. The BIU modules on the two TMU boards in one cabinet can be mutually extended, and the data on the 8 mutually extended E1 lines can be freely switched. The E1 interfaces on the BIU module can be respectively connected to the BSC or to the higher/lower level BTS to complete star, tree, and chain connections.

2) Operation and maintenance unit (OMU)

The OMU module is the core control and processing center of the TMU. Through the OMU, performance parameters of various BIU and MCK units can be directly configured.

The OMU receives fault alarms, handles fault management, and communicates via internal control buses with the CPU of various units (TRX, CDU, PMU, TES, etc.) in the BTS, so as to complete the operation and maintenance of the whole system.

It collectively loads and saves the software of various BTS units before loading software for each unit according to demands. Moreover, it supports the Man-Machine Interface (MMI) connecting to the PC.

The Flash memory of the OMU module can store two different versions of BTS software. One is the software currently used by the BTS and the other one is the previous BTS software. It can load either version according to the requirements to each board.

When the software on the BTS needs to be upgraded, the new version can be loaded from the BSC through OML and saved on the OMU to replace the old version. Meanwhile, the OMU keeps the original software version of the BTS as a backup, in case the loading should fail.

3) Main clock module (MCK)

The MCK is configured with an OCXO (oven controlled crystal oscillator) compliant with the stratum 3 A standard, and phase-locking and frequency-division circuits.

According to system configuration, the MCK can work in the free-run mode or software phase-locked mode to output a reference clock SREF with a stability better



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than 5x10-8. Moreover, it can provide the frame clock FCLK used by radio interfaces, the octet bit clock OBCLK, and the frame number (FN).

The clock source of a synchronous cell is provided by the MCKs on the two TMU boards in the basic cabinet of the basic cabinet group. The MCK modules on the two boards work in hot standby mode. Switchover is made automatically in case of active board failure, which will be reported to the OMU.

4) External alarm collector (EAC)

The EAC collects the alarm signals from environment monitors, including 8 inputs of digital signals for fire, smog, (high/low) temperature, humidity, water, BTS room door control (open/closed), cabinet door control (open/closed), and air-conditioning alarms. For expansion, the EAC also reserves 16 input channels for digital signals, 8 input channels for analog signals and 8 output channels for digital signals. The collected alarm signals are reported to the OMU.

III. Interfaces

Abis interface: One TMU provides 4 E1 interfaces. two TMU boards can provide up to 8 E1 interfaces for connection with the BSC or other BTS (corresponding to different configuration modes of the BTS).

Internal data bus DBUS: provides two 32-timeslot TDMA buses (i.e. DBUS1 and DBUS2) and corresponding clock signals, connecting the TRXs of one cabinet group, and transmitting traffic and signaling data of TRXs. When there are less than 10 TRXs in one cabinet group, 2 buses can work in the active/standby mode.

Internal control bus CBUS: The communication between TMUs is implemented through CBUS1, and that between TMU and TRX is implemented through CBUS2. CBUS3 is responsible for the communication between TMU and low-rate control parts like CDU, PMU and TES, and between TMU and external monitors. For details, refer to Figure 2-8.

Internal clock bus TIMING_BUS: provides clocks (frame synchronization clock FCLK, octet bit clock OBCLK) and frame No. (FN) required by radio interfaces for all TRXs in the synchronous cell, and the highly accurate reference clock SREF for the radio frequency processing unit.

Alarm input interface EAC: provides 24 digital signal inputs, 8 analog signal inputs and 8 digital signal outputs. Among them, the 8 digital signal inputs are external environment alarm inputs, while the remaining 16 digital signal inputs, 8 analog signal inputs and 8 digital signal outputs are reserved for user extension.

Man machine interface: a standard asynchronous serial port or network port, it completes the communication with PC, enabling the operation personnel to perform various operations locally.



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External synchronization clock interface: inputs highly accurate 2MHz clock compliant with G.703 wave forms, which is used as the frequency reference of E1 and system data buses.

IV. Indices

Board size: 280mm×233mm.

Power supply: +26V DC.

Average power consumption: 15W.

2.4.4 TES

TES provides TEU with various types of working power supplies and handles communication transfer. It provides +5V and -5V power and ringing current, so that TEU board can work normally to perform transmission network functions, thus realizing base station built-in transmission.

TES can communicate with TEU and TMU to achieve information reporting from TEU to TMU.

I. Functions

The TES board has the main functions as follows:

Provides the transmission board with DC power supply, including +5V and -5V. Achieves the communication between TMU and TEU. Provides transmission board with ring current, the ringing current signal is the

75V/25Hz sine wave AC signals.

II. Structure

The structure of the TES unit is shown in Figure 2-9.

Communicationmodule

Powersupplymodule

+26 V input1st +5V output

Ringing current output

-5 V output

To the 1st TEU

To the 2nd TEU

To two TEUs simultaneously

To TEU communication serial port

To TMU communication serial port

2nd +5V output

To two TEUs simultaneously

Figure 2-9 TES structure



2-17

Power supply module

The power supply module of the TES board includes two parts, the DC/DC conversion circuit and the DC/AC conversion circuit. The DC/DC conversion circuit converts two +24V DC supplies into +5V DC and one +24V DC supply into –5V DC. The DC/AC conversion circuit converts +24V DC into 75V AC ringing current.

The ringing current module is featured by high performance ringing current signal sources, sine wave output, low distortion, light weight, and high power density. Its output voltage is 75V AC, and its output current is 40mA, with a standard tone of 25Hz.

Note:

Figure 2-9 shows that TES can provide power for 2 TEU boards.

Communication module

The main function of the communication module is to handle the communication between TES and TMU, between TES and TEU, and to acquire the PCB version No. and cabinet No. of the TES board.

The serial port communication between TES and TMU is implemented through RS485 standard. TES is connected with CBUS3 via the level conversion circuit. The serial port communication between TES and TEU adopts the point-to-point mode, with the serial port level as the TTL level.

Communication with TMU mainly includes reporting transmission network information and transmission board information from TEU to TMU, as well as reporting TES board status information to TMU.

Communication with TEU is mainly to acquire transmission network and base station transmission board information.

III. Indices

The board's size is 280mm×233mm, occupying one standard board position.

2.4.5 ASU board

Due to the complexity of network, the base station is required to support multiple external interfaces and flexible networking modes.



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Besides the E1 interfaces, the BTS30 also has the built-in transmission system. It supports the 155M SDH optical interfaces. All these interfaces are provided by ASU. The built-in transmission system makes product networking more flexible and saves user's investment on transmission equipment.

ASU board is used in SDH transmission networks.

1) Basic features

ASU uses Huawei-developed ASIC transmission chips, so the system has an high performance/price ratio and stability. One board integrates all the functions of standard SDH transmission equipment including double STM-1 optical interfaces, 8 E1 electrical interfaces, full cross capabilities, 3 necessary clock phase-lock working modes, order wire, RS232 transparent transmission serial ports, and Ethernet interfaces.

The ASU board provides 4 E1 interfaces with re-timing functions. When users want to use this function (e.g., in the case when GSM and DDN have very high requirements on clock precision), this can be set through network management.

Meanwhile, in application cases such as the GSM base station and private networks, the user can be provided with 64kbit/s sub-rate cross functions between the first 4 E1 so that maximum utilization of transmission resources are achieved.

2) Functions

The ASU SDH optical synchronous transmission system is standard STM-1 transmission equipment. Based on the existing sound technologies of Huawei SBS155/622 products, it is fully compatible with the existing SBS155/622 products. According to networking requirements, it can be configured as a Terminal Multiplexer (TM), Add/Drop Multiplexer (ADM) or regenerator (REG). It can be used to form ring-, chain-, and point-to-point network topological structures. It can also be combined with Huawei SBS155/622H and SBS155/622B products to form complex networking structures so as to enhance network performance and provide powerful services protection functions (channel protection or multiplexing segment protection solutions are optional). It is a cost-effective optical transmission device built in BTS.

The ASU has inherited merits of powerful network management capacity and convenient operations from Huawei's standard transmission equipment. It uses the same set of network management system as all the Huawei SBS series of SDH optical transmission equipment. It can completely meet the OAM & P function specified in ITU recommendations.

3) Interfaces

ASU provides the following interfaces:

Line optical interfaces: 2 (interface type: SC/PC interface) Electrical interface: 4~8 (E1/T1) Order wire: 1



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Ethernet interface: 1 User RS232 port (point to point): 1 Network management interface: Ethernet/RS232

2.4.6 ABB

I. General

In practice, chain networking is usually adopted in BSS networking. This networking mode has the advantage of simple structure and low cost, but also it has the disadvantage that when power failure occurs at a site, all services of the downstream sites will be interrupted. ABB provides of Abis interface bypass function as a solution to the problem above.

II. Functions

ABB is applied in the environment of BTS chain networking. It is in charge of the BTS transmission trunk. When power failure occurs at a certain level (in the middle) of BTS in the chain networking, ABB will bypass the Abis transmission line off this site, and directly connect it to the downstream BTS. In this way, even if power failure occurs at the middle level site in chain networking environment, the services of the downstream site will not be affected. See Figure 2-10.

BSC ABB

TMU

ABB

TMU

ABB

TMU

Site1 Site2 Site3

Figure 2-10 ABB working principle

ABB can also perform loop back at the transmission line, so that in the case of power failure at the last level BTS, ABB will loop back the E1 signal for BSC to detect the quality of the entire transmission link.

III. Location of Board

ABB shares the same slot with TEU, therefore the size of the board and the interface definition is consistent with TEU. Since BTS30 has only one TEU slot, ABB is to take the slot of TEU.



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2.4.7 ABA

ABA realizes the communication between ABB and TMU. ABB communicates with TMU via CBUS3. But the slot of ABB does not provide the connection with CBUS3. Therefore, ABA is used to provide the connection between them. Via ABA, part of the signals from ABB (e.g. the signals of ABA on position) can be transmitted to CBUS3 on the backplane of common resource frame.

2.5 Other Parts of the Cabinet

2.5.1 TDU

The TDU is at the top of BTS cabinet, serving as the control center of BTS clock transfer. It receives the clock source (SREF, OBCLK, FCLK, FN) from TMU, and forwards the clock source to the TRXs in this cabinet and the parts in other cabinets. TDU can also transfer other signals (e.g. alarm signals).

The main functions of the TDU are:

Provides bus-control interface

1) Clock Bus

In the simplex RS485 bus structure, it distributes the clocks generated by the active TMU in the basic cabinet to various extension cabinets, The clock signal process is shown in Figure 2-11.

TMU TDU Boards in the main cabinet

Boards in the extension cabinet

A-bis

Figure 2-11 BTS clock signal process

The TDU of each cabinet is connected to the bus. After receiving clock signals, it transfers them to the TRX in the local cabinet.

The TDU of the last cabinet is connected to an adapter. All the TDUs form a chrysanthemum ring of a clock bus. as shown in Figure 2-12.



2-21

CDU

TRX

CDU

CDU

TRX

TRX

TRX

TRX

TRX

PMU

TMU

TMU

Basic Cabinet

CDU

TRX

CDU

CDU

TRX

TRX

TRX

TRX

TRX

PSU

PMU

Extension Cabinet

CDU

TRX

CDU

CDU

TRX

TRX

TRX

TRX

TRX

PMU

Extension Cabinet

PSU

PSU

Figure 2-12 Clock bus connection in a synchronous cell

Connection path:

Upper cabinet TDUJP3

TDUJP1

TRBJC2

Cable transfer

Inner cable distribution (Connect with 6 TRXs)

Matching

Lower cabinet TDUJP4

TDUJP2

CMBJ24

Inner cable distribution

Cable transfer Cable

transfer


Figure 2-13 Clock bus connection path

For the upper cabinet, JP3 should be configured with connector. For the lower cabinet, JP4 should be configured with connector.

2) Data Bus (DBUS)

DBUS is for the data connection between TMU and TRX. Each TMU provides 2 full duplex DBUS link and TRX connection, called DBUS1 and DBUS2.

The physical feature of DBUS is differential RS485, TDMA synchronous bus and distribution of 32 timeslots is similar to that of PCM.

The active TMU has DBUS connections to each TRX in the same cabinet. The active and standby links are led from the main cabinet to the 18 TRXs in the local cabinet group. There is no DBUS connection between cabinet groups.

For example, the signal connection between BTS30 cabinets is shown in Figure 2-14.



2-22

Figure 2-14 DBUS connection between BTS30 cabinets

The intra-cabinet signal connection is shown in Figure 2-15.


TDUJP5

Cable transfer

Inner cable distribution CMB J25

(connect with TMU)


TRBJC3

TRBJC1

TDUJP7

TDUJP8


Cabletransfer

Lower cabinet

Inner cable distribution(connect with 6 TRXs)

Figure 2-15 DBUS connection path


3) Control Bus (CBUS)

CBUS1 is for the communication between the TMUs of this same site. It adopts RS485 semi-duplex bus, asynchronous transmission. The link layer conforms to HDLC protocol. The bus rate is 256 kbit/s.

Since only the PCM link in main cabinet group has the operation and maintenance signaling of BTS. The master TMU in main cabinet group is to send the operation and maintenance signaling to the slave TMUs in the two extension cabinet groups, as shown in Figure 2-16.



2-23

Figure 2-16 CBUS1 connection between BTS30 cabinets

The connection of the intra-cabinet signal is shown in Figure 2-17.


Cable transfer TDU

JP2

Inner cable distribution CMB J24

(connect with TMU)

TDUJP4

TDUJP2

CMBJ24


Cable transfer

Lower cabinet

Figure 2-17 CBUS1 connection path

CBUS2 is for the control link between TMU and TRX.

The physical feature is differential RS485 interface, semi-duplex bus. The link layer conforms to HDLC protocol. The bus rate is 2 M. The 2 M clock of DBUS is used as the clock of CBUS2. There is no CBUS2 connection between cabinet groups.

The connection relationship between CBUS2 cabinet groups and the connection path are similar to that of DBUS.

CBUS3 is for the connection between TMU and some low rate control parts, such as CDU, PMU and environmental monitoring instruments.

The physical feature is differential RS485 interface. The link layer conforms to DLC protocol, differential transmission and master/slave communication. The bus rate is 9.6 kbit/s. There is no CBUS3 connection between cabinet groups.



2-24

Figure 2-18 Connection of CBUS3 between BTS30 cabinets

The connection of the intra-cabinet signal is shown in Figure 2-19.


TDUJP18

TDUJP5

Cable transfer

Cable transfer

Alarm box

CMB J25(connect with TMU and PMU)

TRBJC3


TRBJP1

TRBJP2

TRBJP3

Cable transfer

CDU


CDU


CDU


TRBJC1

TDUJP7


Cable transfer

Inner cable distributionTDU

JP8

Cable transfer

Lower cabinet

Figure 2-19 CBUS3 connection path


4) Frequency Hopping Bus (FHBUS)

FHBUS is used in baseband FH. FHBUS physically shares the same cable with CBUS2, CBUS3 and DBUS. The difference is that FHBUS connects only to TRX.

FHBUS is an 8 bit parallel bus, semi-duplex, and conforms to RS-485 criteria. FHBUS is for the connection between all TRXs in the same cabinet group (for BTS30, at most 18). There is no FHBUS connection between cabinet groups.



2-25

Main cabinet Extension cabinet

CDU

TRX

CDU

CDU

TRX

TRX

TRX

TRX

TRX

PSU

PMU

TMU

TMU

Extension cabinet

CDU

TRX

CDU

CDU

TRX

TRX

TRX

TRX

TRX

PSU

PMU

CDU

TRX

CDU

CDU

TRX

TRX

TRX

TRX

TRX

PSU

PMU

Figure 2-20 FH bus connection between BTS30 cabinets

Connection path is shown in Figure 2-21.


Cabletransfer TDU

JP5CMBJ25

Inner cabledistribution

TRBJC3

TRBJC1

TDUJP7

TDUJP8


CabletransferLowercabinet


Inner cabledistribution(connect with 6 TRXs)

Figure 2-21 FH bus connection path

For the top level of cabinet, JP6 should be configured with connector. For the last level of cabinet, JP8 should be configured with connector.

Transfers E1 signals in the local cabinet

TMU provides 4 sets of identical circuits E1 for lines. Plus the 4 E1 lines on the standby TMU board, there are altogether 8 E1 signals that are transmitted on the coaxial cable to each cabinet top where the TDU sends them via coaxial cable to BSC.

Provides alarm channels

Inputs of 8 external and 16 extended digital alarm signals and 8 analog alarm signals, as well as outputs of 8 digital control signals, are sent via the TDU to the TMU board and the environment alarm box (for detailed description, refer to section 2.7.1 of this chapter).

The input of the DC alarm signals of fuses and output of DC contactor control signals are also sent via the TDU to the PMU of this cabinet.



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2.5.2 FMU

FMU is in the fan box, used to control the fans.

The small size of the base station cabinet sets higher requirements for heat dissipation. A perfect heat dissipation design should include air tunnels (mainly related to structure), expected dissipation amount (mainly related to circuit working temperature, environment temperature, system total power and efficiency), original calculation of system heat (simulation makes better result if tools are available), fan type, fan monitoring unit, and system heat design testing and verification, etc.

The functions and circuits of FMU are based on the fan type, specific fan control requirements and control modes, as well as the specific system heat design.

It performs the following main functions:

Fan feeding

This part of circuit consists of power supply filtering and power supply voltage dropping. It completes the processing works from system power supply to the working power supply needed by fans, and provides feed to the fans.

Fan speed control

It controls the fan speed so that the fan can maintain a constant rotation speed, meeting the system heat design requirements.

Alarm detection

Fan faults have 2 types, blocking and short-circuiting, both may stop fan running. The FMU monitors the fan rotation speed, and determines the fan status (normal or faulty). If fault is detected, alarm will be reported to the PMU.

Interfaces

The FMU provides the following ports: fan 24V power supply input port, fan box power supply input port, and fan fault alarm terminal, which outputs low levels in case of fan failure.

2.5.3 Switch Box

The +26V DC from the output busbar of the power supply backplane is inputted to the switch box, and after passing the air switches for different power consumption units and over-current protectors, it is outputted to the terminals on the backplane. These terminals are connected to the power input terminals of different power consumption units, thus achieving distributed power supply.



2-27

The distributed power supply ensures the normal power supply to other units when the supply to one unit fails.

The power supply to CDU, EDU, TRX, TMU, PBU, etc., can be controlled through the switches on the front panel of the switch box.

2.5.4 Fan Box

There are two kinds of fan boxes, one small fan box below the switch box, and two large boxes below the second TRX/CDU frame. Both kinds of fan boxes are equipped with FMU.

The fan box uses mixed-flow fans, which feature strong wind rate and pressure. The FMU ensures the normal operation of fans, and reports alarms in case of failure.

2.5.5 Air Box

The air box is at the bottom of the cabinet, under the first TRX/CDU frame. It is the channel for introducing the external cool air into the cabinet to ensure the normal operation of the whole BTS system.

2.6 Antenna and Feeder System

The antenna and feeder system of the base station mainly consists of the antenna, feeder, jumper, lightning arrester, tower-top amplifier (optional), etc. as shown in Figure 2-22. Its main function is to transmit modulated signals and receive signals from mobile stations.

Cabin

et

Tx/Rx antenna

Towe

r-top

ampli

fier

Diversity Rx antenna

Lightn

ingar

reste

r

Antenna and Feeder System

Feeder

Feeder

Towe

r-top

ampli

fier

Lightn

ingar

reste

r

Figure 2-22 Composition of antenna system



2-28

2.6.1 Antenna

The antenna is the terminal of transmitting and the start of receiving. Antenna type, gain, coverage pattern (including azimuth angle, pitch angle and declination angle), and front/back ratio will affect system performance. A network planner sets these parameters according to network requirements.

I. Antenna gain

Antenna gain indicates the antenna feature of electromagnetic radiation in specific directions. Normally, the higher the gain, the stronger the field strength in the main beam radiation direction (which means a larger coverage area), but nearby blind area might occur.

II. Antenna pattern

The antenna pattern describes the radiating abilities of antennas in all directions. (usually in terms of horizontal azimuth angle and declination angle).

Usually, there are two kinds of base station antennas: omni and directional antennas according to the azimuth angle: Omni antenna radiates the waves in all directions i.e. along 360 degrees, whereas directional antennas radiates along 120, 90, or 65 degree.

The declination angle of the antenna can be achieved through mechanical adjustment or electric tuning. BTS directional antennas with declination angle of 0 or 2 are available. Through adjustment by pitch adjuster, a wider angle can be achieved (e.g. 0~ 10).

III. Polarization

Polarization is used to describe the direction of electric field. Mobile communication antennas include single polarization antennas and dual polarization antennas. For the later antennas, two antenna's polarization directions are vertical to each other. So using of dual polarization antennas can reduce the number of antennas needed.

IV. Diversity

Radio communication is much more complex than fixed line communication because of electromagnetic waves propagation. In urban areas, the propagation of electromagnetic wave has the following features:

The average value of field strength varies slowly with distance and time. Such variation abides by the logarithmic normal distribution. This is called slow fading.



2-29

The instantaneous value of field strength presents a selective fading along transmission paths due to multi-path transmission. Its fading pattern abides by the Rayleigh distribution. This is called fast fading.

Either fast fading or slow fading will affect the quality of mobile communications, or even lead to communication interruption. The diversity receiving technology is one of the most effective ways to deal with fast fading. Two receiving signals from two different antennas effectively decrease the fading effect.

Diversity includes polarization diversity and space diversity. In existing mobile communication systems, either the space diversity or polarization diversity can be used. Theoretical inferences show that in case of space diversity, when the distance between two antennas is greater than 10 wavelengths, desirable diversity gain can be obtained. Polarization diversity enjoys the advantage of convenient antenna installation and space saving and is more widely used nowadays.

V. Antenna spacing

To reduce interference on the receivers, enough spacing should be reserved between receiving and transmitting antennas. Spacing is determined by the out-band noise of the transmitter and receiver sensitivity. In the GSM system, the antenna spacing should be greater than 30dB.

2.6.2 Feeder

To reduce transmission loss, the base station uses low loss RF cables. There are several types of main feeders available, including 7/8-inch and 5/4-inch. 1/2-inch super-flexible jumpers are used between the antenna and the main feeder, between the antenna and the tower-top amplifier, and between the cabinet and the lightning arrester.

2.6.3 Lightning Arrester

The lightning arrester is used to prevent damage of lightning current to the antenna and feeder system. Usually, there are two kinds of lightning arresters. The first type applies the microwave principle to conduct the low frequency lightning current to the ground so as to discharge the current. The second one is a discharging tube, when the voltages at both ends of the discharging tube reach a certain value, the tube conducts and discharges the large current. The second technique is used in the BTS30.



2-30

2.6.4 Tower-top Amplifier (Optional)

To further improve the signal quality, Huawei BTS30 offers a complete solution by providing the tower-top amplifier.

The tower top amplifier is optional. Normally it is installed close to the antennas, consisting of triplex filter and low noise amplifier. The triplex filter is actually a device composed of two duplex filters.

Signals from the antennas first pass through the triplex filter to filter out the out-band interference, then the low noise amplifier amplifies the weak signals. Finally the amplified signals are sent over the low loss cable to the BTS, as shown in Figure 2-23.

The purpose of the tower top amplifier is to enhance the receiving sensitivity of the base station. So the tower-top amplifier is required to have a low noise coefficient.

The power of the signals received on the antenna varies greatly with the distance between the MS and the base station. This requires that the tower- top amplifier have a greater dynamic range.

Besides, the tower-top amplifier also has the by-pass function in case of DC power failure.

The DC power supply of tower-top amplifier is fed through the center conductor of the receiving feeder by the CDU. Since it is an outdoor device, a reliable waterproof sealing is required.

The tower-top amplifier can operate under -40C~60C.

Bias-T

Low noiseamplifier

Transmitting filter

Receivingfilter

By-path

DC

BTS

Triplex tower-top amplifier

Receivingfilter

Figure 2-23 Structure of the triplex tower-top amplifier



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2.7 Power Supply System

2.7.1 Overview

The BTS30 built-in power supply system provides +26V DC to the base station. Together with power distribution, lightning arrester, and monitoring systems, they form a complete power supply system.

To meet the power supply requirements of different users, two special AC/DC and DC/DC power supply systems are provided, which are used respectively for the AC power supply cabinet and the DC power supply cabinet.

The AC/DC power supply system has battery charging functions. The PSU power supply unit described above consists of the AC/DC power supply module and the DC/DC power supply module.

According to the general design requirements of the BTS30, multiple cabinets can be configured at a site, which are interconnected via multiple sets of buses to achieve flexible, convenient and reliable network configurations. So a proper power distribution monitoring solution is required for the power supply system, e.g., centralized anti-lightning protection, and AC and DC power distribution. That is, each cabinet should have its own power supply system.

The power supply monitoring board installed on each cabinet monitors its own power supply module and part of environment parameters inside the cabinet, and reports them to TMU via general monitoring bus.

The AC and DC inputs of the system has the following 3 modes, among them only one can be selected:

220VAC: used for the AC power supply cabinet, with the AC/DC module and batteries attached.

-48VDC: used for the DC power supply cabinet with the DC/DC module, no battery attached.

+24VDC: used for the DC power supply cabinet, without AC/DC module or DC/DC module, nor any battery.

The power supply input goes through the AC EMI filter or DC EMI filter to the wiring terminals on the top of the cabinet, then to the backplane busbars in the common frame. 220V AC and -48V DC are input to different sockets from the backplane busbar, so as to avoid mistaken insertion.

No matter whether it is the 220V AC power distribution, -48V DC power distribution solution, or the +24V power distribution, their outputs are all collected to the output



2-32

busbars of the power supply backplane. Then, the 26V DC is led out from the busbar, along the cabinet wiring trough to the copper bar of the distribution box.

The 26V DC input from the battery is connected to the current diverter on the power supply backplane, and then distributed through the distribution copper bar in the distribution box to various power-consuming modules. They are respectively led out from the distribution copper bar, passing the over-current protection devices set separately for each power-consuming unit in the distribution box, and then connected to the outlet terminals on the backplane of the distribution box. When the power to a unit is cut due to over-current, other units will not be affected.

The illustration of the entire power supply system is as shown in Figure 2-24.

Anti-lightning

power

distribution

Battery group Fuse

AC/DC(DC/DC)module

AC/DC(DC/DC)

AC/DC(DC/DC)

EMIfilter

EMIfilter

EMI filter

220V AC IN

-48V DC IN

+24 VDC IN－

＋

＋

－

PMU

26V DC OUT

DC contactor

Load

module module。。。

AC/DC(DC/DC)module

Figure 2-24 The BTS30 power supply system

2.7.2 Overall Structure

I. AC/DC power supply system

220V AC is led in after passing through the AC input anti-lightning power distribution unit and the AC EMI filter on top of the cabinet. It then passes downward along the cabinet wiring trough to the input busbar on the backplane of the power supply frame.



2-33

On this backplane, there are the 220V AC power supply busbar, -48V DC busbar, and 26V DC busbar. When the AC/DC power supply module is used, the -48V DC busbar should not be connected to.

A fully configured cabinet uses the 4 AC/DC (26V/25A) modules (3 active + 1 standby), which can ensure a maximum output of 2600W.

The module size is 285mm×233mm(6U)×60.5mm(12E).

The structure of the AC/DC power supply system is shown in Figure 2-25 (For the battery part, refer to Figure 2-24).

AC input anti-lightning power distribution unit A1441Z

PSU PSU PSU PSU

220 V AC INPUT Input busbar

Output busbar

26V DC OUTPUT

DC distribution copper bar

PMU

Figure 2-25 Structure of the AC/DC power supply system

II. DC/DC power supply system

The DC/DC power supply system uses a backplane the same as that for the AC/DC system. -48V DC first passes through the DC EMI filter on top of the cabinet, then downward along the cabinet wiring trough to the input busbar of the power supply backplane.

On the backplane of the power supply frame, there are 220V AC, -48V DC and 26V DC power supply busbars. When the DC/DC power supply module is used, the 220V AC busbar should not be connected to.

In full configuration, 4 DC/DC 26V/25A modules (3+1 standby) are used to provide a maximum output of 2680W.

The module size is the same as that of the AC/DC module, i.e., 285mm×233mm (6U) × 60.5mm (12E).

The structure of the DC/DC power supply system is shown in Figure 2-26.



2-34

PSU PSU PSU PSU

Input busbar

Output busbar

26V DC OUTPUT

DC distribution copper bar

-48 V DC INPUT

PMU

Figure 2-26 Structure of the DC/DC power supply system

2.8 Environment Monitoring System

It is not practical to monitor the BTS locally. Compared with the switch room, the facilities in the BTS room are quite simple, and their operation environment can be rather hostile. To ensure the normal operation of the base station equipment, and to cope with various possible emergencies (e.g. fire, floods), a perfect environment monitoring system is required.

The environment monitoring system consists of BTS alarm port and environment monitoring instrument. BTS30 supports 14 switching/digital inputs, 8 digital outputs and 8 analog inputs, collects external alarms and controls external equipment. EAC1 and EAC2 on the cabinet top are the physical ports for external extended alarm and EAC alarm report.

The environment monitoring instrument is used to get the information on external environment. It reports the alarm to BSC via TMU if the external environment parameters meet the corresponding alarm terms. The external extended alarm is switching (digital) signals, which is different from the EAC alarm.

The following gives the alarm functions provided by the environment monitoring instrument.

2.8.1 Outlook of Environment Monitoring Instrument

The environment monitoring instrument consists of such sensors as host, humiture probe, smoke probe, infrared probe, infrared tube, door status (position) switch etc. Each probe connects to the host with cables.



2-35

Dimensions of the host:

Length (L) x Width (W) x High (H) = 390mmx270mmx55mm. The outlook of the environment monitoring instrument is shown in Figure 2-27.

Figure 2-27 Outlook of Environment Monitoring instrument

2.8.2 Function Provided by Environment Monitoring Instrument

The environment monitoring instrument automatically monitors and generates temperature, humidity, smog, and intruder alarms according to the set values. Besides, it can start corresponding protection devices for fire-fighting moistening and anti-burglary protection, etc. Moreover, it can receive commands from the control center to modify parameters and start/stop protection devices.

The features of the environment monitoring instrument include:

Realtime display of temperature and humidity Time display Generating alarms including fire, smog, temperature, humidity, water and 3 kinds

of burglar alarms A panel control keyboard 10 switch parameter inputs (opto-electrical isolation) 6 relays (maximum 5A/220V) to drive external executors 2 PWM (pulse width modulation) outputs (8-bit resolution, with a basic clock

500kHz) Driving of 7 independent open-collector gates (absorbing current: 300mA) Capable of communicating with TMU via the RS422 port

2.8.3 Environment Monitoring Instrument Inputs

Temperature: frequency-type temperature and humidity transducer Humidity: frequency-type temperature and humidity transducer



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Smog: Ion type smoke sensitive probe or opto-electrical type smoke sensitive probe

Flame (optional): fire probe or high temperature difference sensitive probe Anti-burglary detection: infrared detector, opto-electrical detector, and magnetic

sensor Other sensor inputs: besides the quantitative temperature and humidity signal

parameters, the above sensor input signals can be extended into 10 switch parameters

2.8.4 Alarm Indicators

Ten red indicators on the panel are provided, which correspond sequentially to the following alarm parameters:

Fire alarm: fire alarm is determined by the high temperature and smog probe Smog alarm: smog sensor timeout alarm Temperature upper limit: an alarm is generated when the environment

temperature exceeds the set temperature limit Temperature lower limit: an alarm is generated when the environment

temperature is lower than the set temperature limit Abnormal humidity: an alarm is generated when the environment humidity goes

beyond the normal range between the upper and lower limits Water: the alarm is generated when water is detected Air-conditioning: an alarm is generated in case of failure of air-conditioning

equipment. Opto-electrical: used for anti-burglary purpose, the alarm is generated when the

opto-electrical switch is triggered. Infrared: used for anti-burglary purpose, the alarm is generated when the

infrared sensor detects outputs. Access control: used for anti-burglary purpose, the alarm is generated when the

magnetic access control switch is triggered.

If there are multiple input signal channels for the same kind of sensor, alarm in any channel will be regarded as the same kind of alarm, regardless of the specific channel sending the alarm. Except temperature and humidity sensors, all other sensors can be extended up to 10 channels at the most.

2.8.5 Executing Devices

The BTS30 environment monitoring function involves the following executing devices:

Six constant on/off relays (A~F) which function as the control and protection devices, operating under 1A/220V. Their specific application can be determined by the user. Their default settings are as follows:



2-37

Relay A starts the cooling devices, activated when the temperature exceeds the set upper limit.

Relay B starts the heater, activated when the temperature drops lower than the set lower limit.

Relay C starts the desiccator, activated when the humidity exceeds the set upper limit.

Relay D starts the moistener, and is activated when the humidity is lower than the set lower limit.

Relay E starts the fire-extinguisher, activated when the fire alarm is given. Relay F starts the anti-burglary alarm, activated in case of burglary alarm.

Two pulse width modulation outputs (PWM) are driven by the open-collector gate, with a driving current of 300mA, a period determined by the user, default value as 1 second, and a resolution of 8 bits (0~255).

Seven open-collector gate outputs, with a driving current of 300mA to control the executors specified by the user.

2.8.6 Communication

There are two-way communication links between the environment monitoring instrument and TMU. The environment monitoring instrument can report alarm and data through this link to TMU. TMU can control the alarm box to start protection devices and set alarm parameters by issuing commands.

2.9 Lightning Protection System

The BTS30 cabinets are connected with the power supply equipment through the power cables and with the base station controller (BSC) via the trunk cables.

Lightning protection for the base station mainly includes lightning protection for the power supply system and that for the trunk cables.

The BTS30 cabinet supports three types of power supply: 220V AC, -48V DC and 24V DC. As lightning protection for -48V supply system is the same as that for 24V supply system, except for parameters setting. Only the lightning protection for AC power supply and that for -48V power distribution are described here.

75 coaxial cable (E1), 120 twisted-pair cable (E1) and optical fiber (SDH) can be used as the trunk cable for BTS30. For optical fiber the fiber pigtail is used for the connection with the base station, therefore, its lightning protection is not covered here.



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2.9.1 Lightning Protection for DC Power Supply

I. Lightning current lead-in paths

DC power supply to telecom equipment is generally provided by the AC power supply. The possibility for the DC power supply port being struck by lightning is very low. But lightning current could be led into the DC power supply port in some ways, including:

In times of –48V power supply, the positive pole of DC power cable is grounded at the power supply equipment and the communication equipment. If the grounding point of the communication equipment is different from that of the power supply equipment, a surge current could be caused from the positive pole of DC power supply to the grounding point of the communication equipment due to the transient potential difference between the two grounding points.

The effect of alternating magnetic field during lightning includes the following two cases. First, the positive pole of DC power supply is grounded at both ends of the power supply equipment and the communication equipment. If the grounding of the power supply is connected with that of the communication equipment at some point, induced current will be generated in the alternating magnetic field of lightning through the close loop formed by the positive wire of DC power supply and the grounding cable of the two equipment. Second, the alternating magnetic field of lightning will generate an induced electric potential at both ends of the negative wire of DC power supply.

If the DC power cables of several devices (including the devices with subscriber lines, such as the switch) in the telecom equipment room are connected to the same set of power terminals, the lightning current induced by the subscriber lines can be transferred to the DC power supply of other equipment through the power supply system, because the subscriber lines are powered by DC power supply.

Surge current is led in through AC power cables and output to DC power cables through the primary power supply.

Huawei provides a DC lightning arrester which is connected in serial to -48V power supply to protect the equipment efficiently from lightning strike.

II. Principle of DC lightning arrester

The circuit of this module is designed based on massive experiments. It is a 3-level protection circuit. The function of the inductor is to suppress current mutation so that the voltage-sensitive resistor group can function normally.

At the first level, two voltage-sensitive resistors are connected in parallel to increase the lightning current discharge capability. The protection circuit of the second level is the same as that of the first level. The protection circuit of the third level clamps the residual voltage at about 100V.



2-39

Its functional blocks are shown in Figure 2-28.

Over-currentprotection

Inductor Inductor-48V -48V

GND GND

Input Output




V-sensitiveresistor

V-sensitiveresistor

V-sensitiveresistor

TVScomponent

Figure 2-28 Functional blocks

2.9.2 Lightning Protection for AC Power Supply

I. Lightning current lead-in paths

AC power supply suffers directly from lightning strike or induced lightning.

II. Principle of the AC lightning arrester

The principle of the AC lightning arrester is similar to that of the DC lightning arrester. The functional blocks are shown in Figure 2-29.

Slow-blow fuse

V-sensitive resistor

Discharge tube

Inductor

Air switchIN OUT

V-sensitive component

Figure 2-29 Functional blocks of the AC lightning arrester

The lightning protection system features:

Symmetric design, N and L wires can be connected freely without affecting the performance.



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2-level lightning protection guarantees high reliability and less possibility of damage by lightning strikes.

2-level protection and 2-level alarm are provided (visible alarm. If either level fails, corresponding indicator will be off. On/off signals of the dry contactor are also provided). The circuits are designed in parallel so that the maintenance personnel can repair them without power-off.

The total through-flow current is 40A. There are two output terminals so that two cabinets can share one anti-lightning box.

2.9.3 Lightning Protection for Trunk Cables

There are three kinds of trunk cables in BTS30: 75 coaxial cable (E1), 120 twisted-pair cable (E1) and optical fiber (SDH). In case of optical fiber connections, fiber pigtail is used so that its lightning protection is not considered.

BTS30 E1 interface protection is realized by adding a E1 lightning protection board to the top of the cabinet. Each board has eight pairs of E1 protection units and two DB37 connectors. The E1 lightning protection board is illustrated in Figure 2-30.

TX0

TX1

TX2

TX3

TX4

TX5

TX6

TX7

RX0

RX1

RX2

RX3

RX4

RX5

RX6

RX7

To L

ine

To E

quip

men

t

LightningProof Box

Figure 2-30 E1 lightning protection board

All E1 cables are protected by the lightning protection board, which is able to avoid the thunder current from entering the cabinet via E1 cable. Even the strong current impact can be discharged by the discharging tube. The lightning protection board is illustrated in Figure 2-31.



2-41

E1-Tip E1-Tip

E1-Ring E1-Ring

PE PE

·Discharging tube

··Discharging tube

4.7¦¸

4.7¦¸

Figure 2-31 Circuit of lightning protection board


System DescriptionChapter 3 Software Architecture

3-1

Chapter 3 Software Architecture

3.1 Overview

The BTS30 software is mainly composed of signaling processing program, baseband signal processing program, operation & maintenance program, BTS testing program, etc.

They implement the function of radio link layer protocols and Abis interface protocols, manage radio channels in real time, and all internal connections/communication, control the transmission equipment, execute operation & maintenance functions for each part of the BTS, and provide Man-Machine Interface (MMI) for local management.

I. Signaling processing program

Only through signaling can different entities in the network coordinate and information be transferred. So between BTS and BSC, not only speech and data, but also signaling for call control are transmitted.

The Signaling Control Processing (SCP) program is the control part of the TRX. It transparently transmits layer 3 messages of the Um interface to the Abis interface, and works with the BSC to perform radio resources management functions and part of the layer 3 functions of the Um interface.

It completes the data link layer functions (LAPD) of the Abis interface and the data link layer functions (LAPDm) of the Um interface.

The SCP is also responsible for the operation and maintenance functions of TRX.

The SCP program is the core of the BTS30 service processing. It implements most of the service processing functions of The BTS30.

The SCP program runs in the transceiver baseband processing unit (TBPU) of the TRX module.

II. Baseband signal processing program

The baseband signal processing program, together with the hardware circuit in the digital signal processing unit of the TRX module, performs the physical layer functions of the Um interface. Its major functions include the coding/decoding of speech, data and signaling on radio channels, modulation of the transmitted signals and demodulation of the received signals.



3-2

Signal transmission over radio channels features high bit error rate due to its time-varying characteristics, interference of various random noises, multi-path fading, and shadow effect.

To ensure high quality signal transmission, the signals carrying user and signaling data shall be transformed into another form suitable for radio transmission at the transmitting end, and converted back to the original form at the receiving end. Such conversion includes the processes of channel coding/decoding, interleaving/de-interleaving, burst formatting, encryption/decryption and modulation/demodulation.

The baseband signal processing program is running on the TBPU board of TRX module.

III. Operation & maintenance program

The operation and maintenance program is the common control part in the BTS30 software as well as the core of BTS operation and maintenance functions.

The functions of the operation and maintenance program include BS software loading, BS initializing, BS operational status monitoring and management, alarm collection, resources utilization and interface message tracing.

The BTS30 interface equipment (hardware) is integrated as a module in the TMU, and the corresponding transmission equipment control system is also integrated into the operation and maintenance software for controlling the transmission link between BSC and BTS.

Through the control program of the transmission equipment, the transmission links between BTS and BSC can be flexibly configured to support star, tree, chain and ring topologies.

This control program also supports the remote loopback testing via the TMU.

Operation & maintenance program and the transmission equipment control program run in the TMU board.

3.2 Signaling Control Processing (SCP) Program

The SCP program is the control part of the TRX unit and performs the following functions:

Layer 3 signaling functions, including:

Radio resource management functions specified in GSM 08.58 and GSM 04.08. Coordination with TMU board software to implement operation and maintenance

functions specified in GSM 12.21.



3-3

Data link layer functions, including:

Data link layer functions (LAPD, GSM 08.56) on the Abis interface. Data link layer functions (LAPDm, GSM04.05, GSM 04.06) on the Um interface. Data link layer functions on the internal interfaces with TMU.

Media control layer functions, including:

CBUS signaling channel control functions with TMU. DBUS signaling channel communication functions with BSC. Mailbox communication functions based on the HPI interface with DSP.

The layer 3 functions of the signaling processing program include 3 parts: radio subsystem management, operation & maintenance interface management and LAPD layer 2 entity management.

The radio subsystem management part includes:

Radio link management, including setup and release of radio links between BTS and MS, and transmitting transparent messages between MS and NSS.

Dedicated channel management, i.e., dedicated channel activation/deactivation, signaling and user data encryption/decryption, dynamic power control of BS and MS, MS timing advance control, etc.

Common control channel management, such as random access detection, dispatching, combining and sending of immediate-assignment messages and paging messages, system message modification, etc.

TRX management, such as idle channel quality detection, reporting BTS overload information and other kinds of faults.

The operation & maintenance interface part interfaces and works with the operation & maintenance program to perform the following functions:

TRX software loading. TRX initializing. Alarm and status management. Equipment self-testing. Resources monitoring and signaling tracing.

The LAPD layer 2 management part manages data link entities at the Abis interface side.

The architecture of the signaling processing program is shown in Figure 3-1.



3-4

SCP layer 3 signaling

Data link layer

Media control layer

HDLC LAPDm

Mailbox

CHDSP

CBUS

LAPD

DBUS

BSC TMU

SCP: Signaling Control Processing LAPD: Link Access Protocol on the D channel HDLC: High-level Data Link Control LAPDm: Link Access Protocol on the Dm channel BSC: Base Station Controller TMU: Timing/Transmission and Management Unit DBUS: Data BUS CBUS: Control BUS CHDSP: Channel Digital Signal Processing

Figure 3-1 The architecture of the signaling processing program

3.3 Baseband Signal Processing Program

The functions of the baseband digital signal processing program include:

Digital demodulation functions. Encoding and decoding, interleaving and de-interleaving of speech, data, and

signaling on the radio channel. Encryption and decryption of speech, data, and signaling on the radio channel. In-band control and transmission functions of speech and data. Rate adaptation of speech and data between the radio channel encoding module

and the transcoder. Provisioning of the internal signaling with L3 module and the primitive

communication with the LAPDm module. Communication with operation and maintenance.

The architecture of the baseband signal processing program is shown in Figure 3-2.



3-5

Message and primitive processing common module

Logical subchannel message and primitive processing module

BIU SCP CUI

I/O module

Deinterleaving module

Channel dec. module

. . .

Baseband signal processing program layer

O&Mmodule

Burst formatting module

Decyphering module

Subchannel 1 processing

Subchannel n processing

Common moduleRadio channel allocation module

Embedded realtime operating systemRate adapter unit

Interleaving module

Channel coding module

Burst formatting module

Cyphering module

BIU: Base station Interface Unit SCP: Signaling Control Program CUI: Carrier Unit Interface controller I/O: Input/Output

Figure 3-2 Architecture of the baseband signal processing program

As shown in the figure, in downlink direction, signaling and speech are first channel-encoded and interleaved, then the bits whose sequences are associated are de-associated and formatted into bursts, after encryption and modulation, they are sent to the carrier interface unit. The process is reversed in the uplink direction.

3.4 Operation and Maintenance Program

The BTS30 operation and maintenance program allows users to operate and maintain the BSS remotely through the OMC Shell or locally through MMI.

I. Hardware architecture

The BTS30 operation and maintenance program runs on the TMU board. The TMU is connected with BSC and local maintenance terminals in the uplink direction, and connected with various boards of the BTS in the downlink direction. The active and



3-6

standby TMUs monitor the operation/maintenance and management on all devices of a BTS.

Hardware structure of operation and maintenance program is shown in Figure 3-3.

Active TMU

BSC

MMI

Extended TMU

CDUCDU CDU

CDUCDU CDU

Standby TMU Standby TMU

PMUPMU PMU

PMUPMU PMU

TRX

TRX

TRX

TRX

TRX

TRX

Low speed DCLLow speed DCL Low speed DCL

High speed DCL

High speed DCL

High speed DCL High speed DCL

BSC: Base Station Controller MMI: Man Machine Interface TMU: Timing/ Transmission and Management Unit CDU: Combiner & Divider Unit PMU: Power Monitoring Unit TES: Transmission Extension power Supply Unit TBU: Transceiver Baseband Unit HR DCL: High-bit Rate Diagnostic Control Link LR DCL: Low-bit Rate Diagnostic Control Link

Figure 3-3 Architecture of the operation and maintenance program

II. Functions

1) Layer 3 signaling functions Remote software loading for all parts of the BTS30 (including BTS itself), so

there is no need to replace the program firmware at site. Monitoring and controlling the status of all channels and boards, as well as

blocking/unblocking of all channels. Setting of the BTS operational parameters, such as BTS attributes, carrier

related attributes and channel related attributes, and controlling of the Abis interface circuits.

BTS devices testing, including loopback testing of the BTS radio unit, testing of boards, and locating faults if any fault is detected.

Interface tracing, especially on the Um interface along with other BTS internal interfaces.

Alarm monitoring, detection of BTS internal alarms, such as various board alarms, and external environment alarms (e.g., temperature, humidity, fire, etc.). Incase of any major alarm, the operation and maintenance unit can take



3-7

corresponding protection measures, such as cutting off the power supply for power amplifier, to prevent further equipment damage to the equipment.

Operation and maintenance (network management) functions defined in TS GSM 12.21.

Other operation and maintenance functions. 2) Data link layer functions

Data link layer (LAPD, GSM 08.56) on the Abis interface High speed DCL data link layer (HDLC based 1-N, active/standby, bidirectional

acknowledged communication protocol). Low speed DCL data link layer (1-N, active/standby, bidirectional acknowledged

communication protocol). Local maintenance terminal serial port data link layer (point to point,

active/standby, bidirectional acknowledged communication protocol). 3) I/O functions

Abis link, I/O functions of PCM specified timeslot. High speed DCL, I/O functions based on HDLC. Low speed DCL, I/O functions based on UART. UART-based I/O functions with local maintenance terminal.

III. Structure

The BTS30 operation and maintenance program comprises the L3 module, the modules of various link layers, the communication port I/O module, the common module and the transmission equipment control module, as shown in Figure 3-4.

LAPD High speed DCL Low speed DCL MMI

I/O I/O I/O I/O

A-bis CDU MMIStandby TMU, TBU Extended TMU

Ext. TMU link

I/O

L 3 Transmission equipmentcontrol module

BIU module

LAPD: Link Access Protocol on D channel DCL: Diagnostic Control Link MMI: Man-Machine Interface BIU: BTS Interface Unit I/O: Input / Output TMU: Timing/Transmission and Management Unit TBU: Transceiver Baseband Unit CDU: Combiner and Divider Unit

Figure 3-4 Structure of operation and maintenance program

The BTS30 operation and maintenance program has interface relationships with all other program modules in the system.



3-8

The BTS30 operation and maintenance program is a multitask realtime program designed with message-oriented and data structure-oriented method. Its object-oriented data structure is represented in the mapping relationship between the tree-type logic structure of the site and the physical boards. Between the functional modules, information is exchanged in form of messages, which reduces the coupling and enhances the cohesion. This design method helps to enhance the system reliability and expandability.

The transmission equipment control module

Performs sub-channel multiplexing and demultiplexing functions on the radio channels, and timeslot switching at the Abis interface or the BS interface.

Monitors the TMU board BIU running status, including E1 line local asynchronization and remote alarming, loop interruption alarming, BS interface link status, etc., and displays (with TMU board indicator) the running status or reports it via the operation and maintenance module when necessary.


System DescriptionChapter 4 External Interfaces

4-1

Chapter 4 External Interfaces

The interface between BTS and BSC is called the Abis interface. It is fully compliant with the GSM 08.5X and GSM12.21 series of specifications. At the Abis interface, each terrestrial traffic channel corresponds to a radio channel.

The interface between MS and BTS is called the Um interface. It is an air interface which guarantees the compatibility between the network and different MSs of different venders. This is one of the basic conditions through which the GSM system implements the global roaming.

4.1 Abis Interface

4.1.1 Introduction

The Abis interface is the interface between the two functional entities of the Base Station Subsystem (BSS), i.e. Base Station Controller (BSC) and Base Transceiver Station (BTS). It is an internal interface of the BSS that connects the remote BTS with BSC through the terrestrial circuit. It is one of the most important interfaces in the GSM system. If the distance between the BSC and BTS is less than 200 meters, the two entities can be connected directly on the physical layer.

I. Features of the Abis interface

The Abis interface of the M900/M1800 digital cellular mobile base station system supports all kinds of services stipulated in GSM standards. It also controls the BTS radio equipment, and allocates the radio frequencies. It has the following salient features:

Support all services defined in the GSM 02 series of specifications. Support smooth expansion of BTS.

II. Description of the Abis interface

The Abis interface comprises a series of specifications, which includes:

Physical electrical parameters. Channel structure. Signaling transmission procedure. Configuration and control procedure. Maintenance and operation support

The hierarchical model of the Abis interface consists of three layers:



4-2

Layer 3: Transparent transmission of layer 3 messages from the A interface and radio resource management function.

Layer 2: (data link layer) based on the LAPD protocol. Layer 1: (the physical layer) 2048kbits PCM digital link. The related protocols of the Abis interface are: GSM 08.52 defines the basic principles for the Abis interface specifications, and

the function division between BSC and BTS. GSM 08.54 defines the physical layer architecture of the Abis interface. GSM 08.56 defines the data link layer protocols of the Abis interface. GSM 08.58 defines the layer 3 procedures. GSM 12.21 defines the transmission system of the OM message on the Abis

interface. GSM 08.60 defines the in-band control protocol of the remote transcoders and

rate adapters.

III. Functional division between BSC and BTS

The BSS is composed of two functional entities, i.e. BSC and BTS.

BTS is the radio part of the BSS under the control of the BSC, providing services for a specific cell. The BTS fulfills the interworking and mapping between the terrestrial channels and the radio channels, as well as the interconnection between the MS and the network via the radio interface (Um interface).

The BSC is the controlling part of the BSS, which manages both the external and the internal interfaces, as well as the radio resource and radio interface parameters.

The specific function division between the BTS and the BSC is shown in Table 4-1.



4-3

Table 4-1 Division of services and functions between BTS and BSC

Location Function

BTS BSC/MSC Remarks

Channel allocation √ MSC-BSC channel Congestion indication √ Channel allocation √

Terrestrial channel management BSC-BTS channel Congestion indication √

Channel configuration management Management √ Frequency hopping Execution √ Channel allocation √ Link monitoring √ Channel release √ Idle channel observation √

Radio channel management

DCH management

Power control decision √ √ Note 1 System information management √

System information broadcast √ Random access check √ Immediate assignment √ DTX paging management √

BCCH/CCCH management

DTX paging execution √ Channel code √ Transcoding/rate adaptation √

Uplink measurement √ Measurement report handling √ √ Note 2 Measurement Traffic measurement √ Calculation √ Indication to MS during random access √

Indication to MS during handover √ Timing advance

Indication to MS during conversation √

LAPDm function √ Management √ Ciphering Execution √ Management √

Radio channel management

Handover Handover access check √ Mobility management √

Call control √ Note: 1. The support of power control in BTS is optional 2. The initial measurement data is reported by BTS to BSC via the Abis interface. As an option, the BSC/BTS may support preprocessing of the initial data in BTS, which reduces the load of BSC.

IV. Structure of the Abis interface

The Abis interface can support three different internal BTS configurations as illustrated in Figure 4-1:



4-4

Single TRX. Multiple TRXs are connected with the BSC via a common physical connection. Multiple TRXs are connected with the BSC via different physical connections.

A-bis

BTS3

BTS2

BTS1

A

A-bis

MSCBSC

TRX

BCF

TRX

TRX

TRX

BCF

TRX

TRX

TRX

TRX

A-bis

BSS

Figure 4-1 Different configurations of the BTS

TRX is the functional entity that supports 8 physical channels that belong to the same TDMA frame, which is defined in the PLMN.

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:

Traffic channels with rates of 8kbit/s, 16kbit/s and 64kbit/s respectively, carrying speech or data from radio traffic channels.

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 (TEIs) are assigned to get unique addresses of TRXs and BCFs. For each TRX and BCF, 3 separate logical links are defined with each TEI, as shown in Figure 4-2.



4-5

RSL: Radio Signaling Link, used to support traffic management procedures, one for each TRX.

OML: Operation & Maintenance Link, used to support network management procedures, one for each SITE or BCF.

L2ML: Layer 2 Management Link, is used to transfer the layer 2 management messages, one for each TRX or BCF.

TEI 4

TEI 3

TEI 2

TEI 1L2ML SAPI=63

RS L SAPI=0OML SAPI=62

Layer 2

TEI

Management

TRX

TRX

TRX

BCF

L2ML SAPI=63


L2ML SAPI=63


BCF

BCF

BCF

BCF

L2ML SAPI=63OML SAPI=62

BSC BTS

Figure 4-2 Abis interface layer 2 logical links

For Abis signaling, refer to Figure 4-3, which is explained in the following text.

BSC and BTS do not resolve 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.

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, encryption, random access, paging and assignment), these messages are processed by the BTSM (BTS Management) entities in the BSC and the BTS.

The layer 2 protocol of the Abis interface is based on the LAPD. The LAPD addresses the TRX (or BCF) through TEI. Different logical links are used for traffic management



4-6

message (RSL, i.e., Radio signaling link), network management message (OML, i.e., Operation & Maintenance link), and L2 management messages (L2ML, i.e., Layer 2 Management link).

Layer 1 of the Abis interface is the physical layer hardware-based bottom driver, responsible for receiving and sending data to the physical link.

CC

MM

RR

LAPDm

Sign.Layer 1

L3

L2

L1

LAPDm

Sign.Layer 1

LAPD

Sign.Layer 1

RR BTSM

MS

Um

LAPD

Sign.Layer 1

SCCP

MTP

BTSM

RR BSSAP

A-bis

BTS BSC

CM: Connection Management BTSM: BTS Management MM: Mobility Management BSSAP: Base Station Subsystem Application Part RR: Radio Resources Management SCCP: Signaling Connection Control Part LAPD: Link Access Protocol on the D Channel MTP: Message Transfer Part LAPDm: Link Access Protocol on the Dm Channel

Figure 4-3 Abis interface signaling model

4.1.2 Physical Layer

The physical layer uses the 2048kbit/s PCM link, providing 32 channels of 64kbit/s. The physical electric parameters of the physical layer comply with the CCITT G.703 recommendations.

The BSS is the connection point of the radio channel and terrestrial channel. Both kinds of channels have different transmission patterns and coding rates. In the radio channel of BSS, the transmission rate is 16kbit/s while it is 64kbit/s in the terrestrial channel. Therefore transcoding and rate adaptation is needed. This function is realized on the physical layer of the Abis interface by the Transcoder & Rate Adapter Unit (TRAU) located at the BSC side or MSC side, depending on the networks requirements. In this case, all speech, data and signaling should be transmitted at the Abis interface at the rate of 16kbit/s or 64kbit/s according to the GSM 08.60



4-7

requirements. But before the transmission, rate adaptation and multiplexing is required, according to ITU-T I.460 recommendation.

Data coding is described in GSM 08.20. The in-band control protocol of TRAU is specified in GSM 08.60.

4.1.3 Data Link Layer

The data link layer of the Abis interface 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. SAP is identified by the 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.

The communication between data link layer entities is governed by a peer-to-peer protocol specific to the layer. In order for information to be exchanged 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.

Messages at the data link layer are transferred between entities at layer 2 of the physical layer.

Data link layer Protocol-Data-Units (PDUs) are conveyed between data link layer entities by means of a physical connection, making use of physical Service-Data-Units (SDUs).

Layer 3 requests services from the data link layer via service primitives. The same applies to the interaction between the data link layer and the physical layer.

The purpose of LAPD is to realize reliable end-to-end information transfer between layer 3 entities through the user-network interface by using the D-channel. Multiple terminals at the user-network interface and multiple layer 3 entities are supported by LAPD.

Functions of LAPD includes:

Providing one or more data link connections on the D-channel. Frame delimiting, alignment and transparency, allowing recognition of a

sequence of bits transmitted over a D-channel as a frame. Sequence control, so as to maintain the sequential order of frames transmitting

over a data link connection. Detection of transmission, format and operation errors on a data link connection.



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Performing recovery operation based on the detected transmission, format, and operation errors.

Notifying the management entity of unrecoverable errors. Traffic control.

The 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 broadcast data link connections.

4.1.4 Layer 3 - Traffic Management

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:

Realizing the interworking of the MS and BSS/NSS on the Um interface. Implementing part of the radio resource management functions under the control

of the BSC.

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

The transparent message refers to the messages forwarded without interpretation or being processed by the BTS.

The non-transparent message refers to the messages processed and constructed by the BTS.

Allocation of channel data links

Other procedures inside BTS

NM procedures

Traffic management procedures

L2 managementprocedures

SAPI = 3

LAPDmRSL NML L2ML

Layer 1

SAPI = 0

LAPD

Layer 1

SAPI = 0 SAPI = 63 SAPI = 62

Allocation

Transparentmessage

Non-transparentmessage

Figure 4-4 Abis interface layer 3 model

The traffic management messages can also be divided into four groups in terms of functions, which are:



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Radio link layer management message, used for the management of the data link layer on the radio channel.

Dedicated channel management message, used for the management of dedicated channels (SDCCH and TCH).

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

TRX management message, used for TRX management.

Transparency and group of the message is determined by the message identifier at the head of the message.

I. Radio link layer management procedures

Link establishment indication procedure: Through this procedure the BTS indicates to the BSC that a multiframe data link has been established at the initiative of an MS. The BSC can use this indication to set up an SCCP connection to the MSC.

Link establishment request procedure: Through this procedure the BSC request the setup of a multiframe data link on the radio channel.

Link release indication procedure: Through this procedure BTS indicates to BSC that a radio link has been released at the initiative of an MS.

Link release request procedure: Through this procedure the BSC requests the BTS to release a radio link.

Transfer procedure of a transparent L3-message in acknowledged mode: Through this procedure the BSC requests the BTS to send a transparent Um interface RIL3 message in acknowledged mode.

Receive procedure of a transparent L3-message in acknowledged mode: Through this procedure the BTS indicates the BSC to receive a transparent Um interface RIL3 message in acknowledged mode.

Transfer procedure of a transparent L3-message in unacknowledged mode: Through this procedure the BSC requests the BTS to send a transparent Um interface RIL3 message in unacknowledged mode.

Receive procedure of a transparent L3-message in unacknowledged mode: Through this procedure the BTS indicates the BSC to receive a transparent Um interface RIL3 message in unacknowledged mode.

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



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II. Dedicated channel management procedures

Channel activation procedure: Through this procedure the BSC sends commands to the BTS to activate a dedicated channel for a certain MS. After the activation, the BSC assigns the channel to the MS using commands such as Immediate Assign, Assign Command, Additional Assignment or handover commands.

Channel mode modify procedure: This procedure is used by the BSC to request the BTS to change the mode of the activated channel.

Handover detection procedure: This procedure is used between the target BTS and target BSC to detect the handover access of the MS.

Start ciphering procedure: Used for starting the ciphering procedure defined in TS GSM 04.08.

Measurement reporting procedure: It includes the necessary basic measurement reporting procedure and optional measurement reporting procedure with preprocessing. The BTS reports all parameters related to the handover and power control decision to the BSC through it.

SACCH deactivation procedure: According to the requirements of channel release procedure specified in TS GSM 04.08, the BSC uses this procedure to deactivate TRX related SACCH channel.

Radio channel release procedure: The BSC uses this procedure to instruct the BTS to release a radio channel, which is not in in-service state.

MS power control procedure: The BSS uses this procedure to control the transmitting power of the MS related to a specific activated channel. MS power control decision must be implemented in the BSC, and as an optional procedure in the BTS.

Base station transmission power control procedure: The BSS uses this procedure to control the transmission power of the activated channel in TRX. The base station transmitting power control decision should be implemented in the BSC, or in the BTS.

Connection failure procedure: The BTS uses this procedure to indicate to the BSC that an activated dedicated channel is already disconnected.

Physical environment content request procedure: The BSC uses this procedure to obtain the physical parameters of a specific channel. This usually occurs before a channel change. This is an optional procedure.

SACCH information change procedure: The BSC uses this procedure to instruct the BTS to change the information (system information) filled in a specific SACCH channel.



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III. Common channel management procedures

MS channel request procedure: This procedure is triggered when the TRX detects random access ("channel request" message) originated from the mobile station.

Paging procedure: It is used to page information on a specific paging sub-channel. It is used when the MS is the called party, initiated by the MSC and paged through the BSC. The BSC determines the paging group to be used according to the IMSIs of the called MSs. The value of this paging group together with the identity of the mobile station is sent to the BTS, and then, the BTS will page the MS on the related paging sub-channel.

Immediate assignment procedure: When a mobile station accesses the BTS, the BSC uses this procedure to assign a dedicated channel for the mobile station immediately.

Deletion indication procedure: The BTS uses this procedure to indicate to the BSC that a RIL3-RR immediate assignment message is deleted (i.e., not put in the AGCH array) due to overloading of the AGCH channel.

CCCH load indication procedure: If the load exceeds the threshold set by OM, the BTS will use this procedure to instruct the BSC to indicate the load on the CCCH channel. The indication period is set by OM.

Broadcast information change procedure: The BSC uses this procedure to instruct the BTS to broadcast new system messages on the BCCH channel.

Short message cell broadcast procedure: The BSC uses this procedure to request the BTS to issue cell broadcast short messages.

IV. TRX management procedures

SACCH filling information change procedure: The BSC uses this procedure to indicate the BTS to use new system information on all downlink SACCH channels.

Radio resources indication procedure: The BTS uses this procedure to indicate the interference level on each idle dedicated channel of TRX to the BSC.

Traffic control procedure: The FUC uses this procedure to indicate the overload condition of the TRX to the BSC, the cause possibly being CCCH overload, ACCH overload or processor overload.

Error reporting procedure: The BTS uses this procedure to report the BSC about detected downlink message errors that can not be reported by other protocols.



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4.1.5 Layer 3 - Operation and Maintenance

I. Operation and maintenance information model

1) Managed objects

There are 4 kinds of objects to be managed, which are sites, BTS, TRX, and channels, as shown in Figure 4-5.

SITE

BTS0 BTS1 BTSn

TRX0 TRX1 TRXm

Baseband transceiver Radio carrier

Channel 7Channel 0 Channel 1 …...

…...

…...

Figure 4-5 Basic structure of managed objects

2) 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 layer 2 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.

3) Managed object state

Management state

The management state of managed objects is only controlled by the BSC. There are three kinds of states, including:

Locked: indicates that BSC has disconnected all calls going through this managed object, and no new calls can be connected to this managed object.

Shutting down: indicates that new services can not be connected to this managed object, but those existing calls will be maintained.



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Unlocked: indicates new services can be connected to this managed object.

Operational state

There are two operational states:

Disabled: indicates that resources are completely inoperable, and can no longer provide services to the users.

Enabled: indicates that all or part of resources are available and can be used.

Available state

The available state is a specific explanation of the operational state. Following are the different states available in the system:

In test: The state during which a resource is being tested. The operational state is "disabled".

Failed: It shows that the source/object is not working due to some internal error. The operational state is "disabled".

Power off: This resource needs power supply. Its operation state is "disabled". Off line: This resource needs manual or automatic operations. Its operation state

is "disabled". Dependency: If a resource depends on other resources and those resources are

not available then it will also be not available/operable. The operational status is "disabled".

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

Unequipped: Hardware or software of the managed objects is not equipped. Its operation state is disabled.

II. Elementary procedure

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, or single formatted O&M messages that need not be responded, are called an elementary procedure.

All formatted O&M messages are sent on layer 2 in form of I frames. A group of procedures, called structured procedures, are based on the combination of several elementary procedures.

For a specific object, if a certain elementary procedure is not completed, the system will not start its subsequent elementary procedures.

When there is no response against the formatted operation and maintenance message from the peer layer 3 before timeout, the elementary procedure is said not be completed.



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When the previous elementary procedure has not received any response (ACK or NACK) before layer 3 timeout, then no subsequent elementary 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. If the ACK message returned by an object is a positive reply, it is used to notify the message sender that the command is or is going to be executed. If the NACK message (i.e. a negative acknowledgement) is returned, it is used to notify the message sender that the command execution has failed, and how it failed.

There are mainly the following types of elementary procedures:

Software loading management Abis interface management Transmission management Air interface management Testing management State management and event reporting Equipment state management

4.2 Um Interface

4.2.1 Introduction

In a public land mobile network (PLMN), MS is connected via the radio channels to the fixed network so that a call can be routed to the specific destination. In order to achieve the interconnection between MS and BSS a set of standard protocols on radio channel signal transmission are specified, which are called the radio interface, or simply the Um interface in GSM.

The Um interface is the most important interface in the GSM system. It is necessary to follow a standard interface so that a complete compatibility can be achieved between different networks of different manufactures, which is the basic condition for global roaming. It also determines the spectrum availability of the GSM cellular system, which is an important measure to evaluate a radio system.

The Um interface is specified by the following features:

Channel architecture and access capability MS-BS communication protocols Maintenance and operation features Performance features Service features



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4.2.2 Interface Protocol Model

The Um interface can be divided into 3 layers, as shown in Figure 4-6.

Signaling layer (L3)

Data link layer (L2)

Physical layer (L1)

Figure 4-6 Um interface layered structure

The first layer is the physical layer at the bottom. It includes various channels, and provides basic radio channels for information transmission to the higher layer.

The layer 2 is the data link layer using the LAPDm protocol. It includes various data transmission structures, and controls data transmission.

The layer 3 is the signaling layer (also called network layer). It includes various messages and programs, and controls services. L3 includes 3 sub-layers, which are radio resources management (RR), mobility management (MM), and connection management (CM).

4.2.3 Physical Layer

I. Working frequency band

Table 4-2 Working frequency bands of BTS30

Uplink (MHz) Downlink (MHz) Duplex spacing (MHz)

Freq. spacing (kHz)

900MHz primary band 890-915 935-960 45 200

1800 MHz band 1710-1785 1805-1880 95 200

II. Physical layer interface and services

The interfaces between the physical layer (L1), data link layer (L2) and radio resources management sub_layer (RR) of L3 and the functions units are shown in Figure 4-7.



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Radio resourcesmanagement (L3)

Data link layer

MPH - primitive PH - primitive

Physical layer

TCH

Other function units

Figure 4-7 Physical layer interface

The physical layer provides the following services:

Access capability: The physical layer provides transmission services through a series of limited logical channels, which are mapped onto the physical channels.

Error code detection: The physical layer provides error-free transmission services, including error detection and correction.

Ciphering

III. Timeslot and frame structure

Both FDMA and TDMA techniques are used by the Um interface, along with frequency hopping. The units transmitted on the Um interfaces are called bursts, each of which comprises over 100 modulated bits. A burst occupies the 200kHz channel, with a duration of 0.577ms(15/26ms) called burst period (BP). The time and frequency window it occupies is called timeslot, as shown in Figure 4-8.

1

2

3

200kHz

0 1 2 3 4 5 6 87Time

Time slotBP

15/26ms

Frequency

Figure 4-8 Concept of timeslot

Each timeslot corresponds to a basic physical channel. Each carrier is divided into 8 timeslots, which can be used by different subscribers. These 8 neighboring timeslots form a basic unit called frame.

A complete hierarchy of GSM frames is illustrated in Figure 4-9.



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0 1 2 3

0 1 2 3

0 1

0 1 2 3

0 1

4 5 6 7

24 25

2044 2045 2046 2047

47 48 49 50

0 1

24 25

49 50

1 hyperframe=2048 superframe=2715 648TDMA frame (3 h28m53s760ms)

BCCHCCCHSDCCH

TCHSACCH/TFACCH

1 superframe=1326 TDMAframe (6.12s)

1 multiframe=51 TDMA frame (3060/13ms)1 multiframe=26 TDMA frame(120ms)

1TDMA=8 TS (120/26=4.61ms)

Figure 4-9 Channel frame structure

One TDMA frame has a duration of 4.615ms (120/26ms), consisting of 8 timeslots. Each timeslot contains 156.25 code elements. An MS sends information on specific timeslots, and the remaining timeslots are used by other MSs.

Higher order frames, called multiframe, consists of 26 or 51 frames. Multiframe of 26 frames has a duration of 120 ms and carries traffic channel, slow associated control channel and fast associated control channel. Similarly, a 51-frame multiframe has a duration of 235.365 ms and carries control channel information.

One superframe consists of 51 traffic multirames or 26 control frames and consists of 51×26 TDMA frames with a total duration of 6.12 seconds.

The highest order frame is called hyperframe and consists of 2,048 superframes or 2,715,648 (2048×51×26) frames. The time duration of the hyperframe is 3 hrs, 28 min and 52.76 sec. The frame number is transferred over SCH channels. Frame numbers are necessary in the hopping algorithm.

IV. Burst type

Five types of burst structures are defined in the Um interface specifications:

Normal Burst (NB): Used to carry information of traffic channels, and control channels except for RACH. It contains 116 encrypted bits and 8.25 guard bits.

Frequency-correction burst (FB): Used for MS frequency synchronization. FB is equivalent to the un-modulated carrier with a +1625/24 frequency offset, it has the same guard period as NB.



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Synchronization burst (SB): Used for MS timing synchronization. SB has a long training sequence bits and can carry the information of TDMA frame numbers (FN) and BS identification code (BSIC).

Random access burst (AB): Used for MS random access. AB has a longer guard period (68.25 bits).

Dummy burst (DB): Used to fill in the domain when there is no information sent. DB has the same structure as NB, except that the bit flow is a fixed bit sequence.

V. Channel type

According to different characteristics, channels are grouped into different types, which are discussed briefly in the following text.

1) Traffic channel (TCH)

TCH channel carries voice or user data. A full rate traffic channel (TCH/F) carries the information with a total bit rate of 22.8kbit/s. On the TCH channel, the following traffic channels are provided:

Full rate speech traffic channel (TCH/FS) 9.6kbit/s full rate data traffic channel (TCH/F9.6) 4.8kbit/s full rate data traffic channel (TCH/F4.8) 2.4kbit/s full rate data traffic channel (TCH/F2.4)

2) Control channel

Control channels carry signaling and synchronization data. According to different processing tasks, there are 3 types of control channels: broadcast channel, common control channel and dedicated control channel.

Broadcast channel (BCH)

A broadcast channel is a point-to-multipoint unidirectional control channel from BS to MS. It is used to broadcast various types of information to MSs. There are three types of BCH.

FCCH: Frequency-correction channel, used for MS frequency correction. SCH: Synchronization channel, used for MS frame synchronization and BS

identification. BCCH: Broadcast control channel, used to send cell information.

Common control channel (CCCH)

A common control channel is a point-to-multipoint bi-directional control channel. It carries signaling information required by access management functions, as well as other signaling. CCCH is shared by all MSs in the network. There are 3 types of CCCH.

PCH: Paging channel, used by BTS to page MS.



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RACH: Random access channel, for random access of MS to the network. It is unidirectional channel from MS to BSS.

AGCH: Access grant channel, used to assign dedicated control channels for the successfully accessed MS.

Dedicated control channel (DCCH)

A dedicated control channel is a point-to-point bi-directional control channel. According to the demand of the communication control process, DCCH are assigned to MS to perform point-to-point signaling transmission with BTS. DCCH includes the following types:

SDCCH/8: Standalone Dedicated Control Channel SACCH/C8: Slow Associated Control Channel/SDCCH/8 SACCH/TF: Slow Associated Control Channel/TCH/F FACCH/F: Fast Associated Control Channel/Full Rate SDCCH/4: Standalone Dedicated Control Channel/BCCH/CCCH SACCH/C4: Slow Associated Control Channel/SDCCH/4

Cell broadcast channel (CBCH)

A cell broadcast channel is used to broadcast cell short messages in downlink direction. It carries short message service cell broadcast (SMSCB) information, and uses the same physical channel as SDCCH.

VI. Channel combinations

Practically different types of logical channels are mapped onto the same physical channel, this is called channel combination. Some channel combinations are listed below:

TCH/F+FACCH/F+SACCH/TF FCCH+SCH+BCCH+CCCH FCCH+SCH+BCCH+CCCH+SDCCH/4+SACCH/C4 BCCH+CCCH SDCCH/8+SACCH/8 SDCCH/8+SACCH/8+CBCH FCCH+SCH+BCCH+CCCH+SDCCH/4+SACCH/C4+CBCH

Where CCCH = PCH+RACH+AGCH

4.2.4 Data Link Layer

Data link layer is the second layer of the OSI model. It is served by the physical layer and serves layer 3. The services access point (SAP) on the data link layer is its connection point for providing services to layer 3. SAP is identified by the services access point identifier (SAPI).



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Each SAP is associated with one or multiple data link connection end points (DLCEP). Viewed from layer 3, DLCEP is identified by data link connection end point identifier (DLCEPI). Viewed from layer 2, it is identified by the data link connection identifier (DLCI).

Communication between the entities on the data link layer is controlled by the peer-to-peer protocol on this layer. In order to exchange information between two or multiple layer 3 entities, this layer protocol should be used on the data link layer to set up connection between layer 3 entities. Such a connection is called a data link connection (DLC).

Data link layer message units are transferred among layer 2 entities over the physical layer.

Layer 3 makes service requests to the data link layer in form of service primitives, the same as the data link layer and physical layer.

I. Functions

1) General

LAPDm transfers information among 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.

LAPDm functions include:

Provide one or multiple data link connections (DLC) on the Dm channel. These DLCs are distinguished by data link connection identifiers (DLCI).

Support frame type identification. Support transparent transmission of layer 3 message units among layer 3

entities. Sequence control, so as to maintain frame sequence order passing via the DLC. Detection of format and operation errors on data links. Traffic control. Contention decision of data links setup when there are access requests to

RACH. 2) Operation types

The data link layer used to transfer layer 3 messages has two types of operations i.e. unacknowledged and acknowledged operations. They can exist on the same Dm channel.

Unacknowledged operation

In this type of operation, layer 3 information is transferred in the form of unnumbered information frames (UI). On the data link layer, UI frames are not acknowledged, nor



4-21

traffic control or error recovery is performed. Unacknowledged operation applies to all control channels except RACH.

Acknowledged operation

In this type of operation, layer 3 information is transferred in numbered information frames (I). The data link layer acknowledges all I frames. Unacknowledged frames are resent for error recovery. In the case the data link layer can not recover the error codes, it sends an error indication to the management layer. Besides, traffic control protocols are defined for acknowledged operation. The acknowledged operation applies to DCCH.

3) Information transfer modes

On different channels, information transfer modes are different, as described below:

Information transfer in BCCH: BCCH exists only in the direction from BTS to MS, used to broadcast system information messages to MSs. On BCCH, only the unacknowledged operation is permitted.

Information transfer in PCH+AGCH: only exists in the direction from BTS to MS. Only the unacknowledged operation applies to PCH+AGCH.

Information transfer in DCCH: Both unacknowledged operation and acknowledged operations apply to DCCH, and are determined by layer 3.

4) Data link release

The multiframe operation can be released as:

Normal release in which BTS and MS exchange DISC frames and UA frames or DM frames, and

Local release with no frame exchange.

Release of the data link layer is initiated by layer 3.

II. Service features

The data link layer provides services to layer 3, and uses the physical layer to provide services. Interaction among them are described by primitives. The primitive format between layer 2 and layer 3 is DL_XX_XXX. The primitive format between layer 2 and the management layer is MDL_XX_XXX. And the primitive format between layer 2 and physical layer is PH_XX_XXX.

1) Providing services to layer 3

Unacknowledged information transfer service

Features of the unacknowledged information transfer service:

Provide data link connection for the unacknowledged transfer of layer 3 message units among layer 3 entities.

Identification of data link connection end points; it permits a certain layer 3 entity to identify other layer 3 entities.



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Sending frames according to message priority. Messages are not detected on data link layer.

The primitive used in unacknowledged information transfer services is DL_UNIT DATA_REQUEST/INDICATION. The primitive DL_UNIT DATA_REQUEST is used when layer 3 requests the unacknowledged operation to transfer messages. At the receiving terminal, the primitive DL_UNIT DATA_INDICATION is used to indicate the arrival of this kind of messages.

Acknowledged information transfer service

Acknowledged information transfer defines only the multiframe operation. Its service features are:

Provide data link connection for the acknowledged information transfer among layer 3 entities.

Identification of data link connection end points, it permits a certain layer 3 entity to identify other layer 3 entities

Ensure the integrity of data link layer message unit sequences in case of nonphysical faults.

Notify the corresponding layer entities in case of fault, such as sending sequence error etc.

Notify the management layer in case non-recoverable errors. Traffic control. Send frames according to the indicated SAPI value. Segmentation and concatenation control functions. Primitives used for multiframe acknowledged information transfer include: DL_DATA_REQUEST/INDICATION: used for transmitting and receiving the

information in case layer 3 requests the acknowledged mode. DL_ESTABLISH_REQUEST/INDICATION/CONFIRM: for setup of the

multiframe mode. DL_RELEASE_REQUEST/INDICATION/CONFIRM: used for the termination of

the multiframe mode.

Random access process

The primitive used by the random access procedure is DL_RANDOM ACCESS_INDICATION, which is used for layer 2 to indicate layer 3 the MS random access message.

2) Services requested from the physical layer

The physical layer provides the following services to the data link layer:

Physical layer connection for transparent frame transfer. Indication of physical state of the Dm channel. Sending data link layer message units. Providing frame synchronization.



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Error control, ensuring a low error rate in data link layers. Receiving random access burst.

3) Management layer services

Primitives used by management layer services:

MDL_ERROR_INDICATION, used by layer 2 to report unrecoverable errors to the management layer.

MDL_RELEASE_REQUEST, used by the management layer to release layer 2 channels.

4.2.5 Signaling Layer

The layer 3 signaling (L3) of the Um interface provides such functions as setup, maintenance and termination of circuit switching connections in a cellular mobile network and other public mobile networks connected to it. L3 also provides the control functions of supplementary services and short messages services. Moreover, L3 includes mobility management and radio resources management functions.

The layer 3 consists of many functional program blocks. These program blocks transfer message units that carry various kinds of information among all layer 3 entities and between layer 3 and neighboring layers.

The layer 3 signaling performs the following main functions:

Setup, operation and release (radio resources management) of dedicated radio channel connections.

Location update registration, authentication and TMSI reallocation (mobility management).

Setup, maintenance and termination (call control) of circuit switched calls. Support supplementary services. Support short message services.

Layer 3 consists of 3 sub-layers including connection management (CM), mobility management (MM) and radio resources management (RR).

The layer 3 functions are performed by the layer 3 signaling protocols between the mobile station and the network on the two sides of the Um interface. Here, no consideration is given to the function allocation between different entities inside the base station system.

Layer 3 and its supported lower layer functions provide higher layers with mobile network signaling (MNS) services.

Interaction between layer 3 and higher layers and between services interfaces of layer 2 as well as that among neighboring sub-layers in layer 3 can be described in primitives and parameters.

On layer 3, information switching among peer entities is performed by 3 sub-layers.



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I. Structure

Layer 3 contains 3 sub-layers, which are further discussed here:

Radio Resources (RR) management handles the setup, maintenance, and release of physical channels and logical channels, as well as cross-cell transfer on the request of CM sub-layer.

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.

Connection Management (CM) sublayer, consists of 3 functional entities including, call Control (CC), Short Message Service (SMS) support, and Supplementary Service (SS) support. These entities have the functions described below:

Call Control (CC) deals with all necessary functions to setup or release the circuit switching connections in which either the mobile subscriber is a caller or a called party.

Supplementary Service (SS) support deals with all necessary functions to support GSM supplementary services.

Short Message Service (SMS) support performs all necessary functions to support point-to-point GSM short message services.

Besides the above functions, layer 3 includes other functions related to message transmission, such as multiplexing and demultiplexing. These functions are specified by radio resources management and mobility management. Their task is to determine message routing according to protocol discriminator (PD) and transaction identifier (TI) which is on the head of message.

In the uplink direction, MM routing function is to transfer CM entity messages and messages of MM itself to the service access point of the RR sub-layer, and multiplex them when multiple messages are transmitted in parallel. The RR routing function is to distribute messages according to the PD of transferred messages and the actual channel configuration.

In the downlink direction, RR sub-layer routing function can distribute the messages from different services access points of layer 2 according to PDs. If the PD equals the RR, then this message is sent to the RR entity of this sub-layer. The remaining messages are provided to the MM sub-layer through the service access point RR-SAP. The routing function of the MM sub-layer is to transfer messages from the RR sub-layer to the MM entities according to PDs and TIs, or to the various entities of the CM sub-layer through each MM-SAP.

Figure 4-10 shows the protocol model of the layer 3 signaling.



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CC

MNCC-SAP

SS

MNSS-SAP

SMS

MNSMS-SAPMobile networkservices

MMREG -SAPMMCC-SAP

MMSS-SAP

MMSMS-SAP

MM CC SS SMSMM

RR-SAP

.. RR

RR

PDRR

SAPI 0 SAPI 3

RACCHFACCH

SACCH

SDCCH

BCCH

SDCCH SACCH

AGCH+PCHL3 signaling

Figure 4-10 Layer 3 protocol model of the Um interface

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.

The 3 independent entities on the CM sub-layer provide services to higher layers through MNCC-SAP, MNSS-SAP and MNSMS-SAP respectively.

II. Service features

1) Services provided by layer 3 at the MS side include Registration services, i.e., IMSI attach and detach operations. Call control services, including normal MOC setup, emergency MOC setup, call

hold, call completion, and call-dependent supplementary services.



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Support for call-independent supplementary services. Support for short message services.

2) Services provided by layer 3 at the network side include Call control service, including call setup, call hold, call termination and

call-dependent supplementary service support. Support for call-independent supplementary services. Support for short message services.

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

Services provided by radio resources management entities (RR)

These services are provided to MM via RR-SAP. They are used for setting up control channel connections and traffic channel connections, indicating encryption mode, releasing control channel connection, and controlling data transmission. Figure 4-11 shows the RR sub-layer communication.

RRSAP

MS side Network sideMobility

managementsub-layer

RR－primitive

Peer layer protocolof RR sub-layer

Radioresources

managementsub-layer

Figure 4-11 RR sub-layer communication

Services provided by mobility management entities (MM)

These services support call control, supplementary services and short messages services of connection management entities. MM sub-layer communication is shown in Figure 4-12.



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CC SMSSS

MS side

CC SMSSS

Network side

Mobility managementsub-layer

MM peerlayer protocol

Mobility managementsub-layer

Figure 4-12 MM sub-layer communication


System DescriptionChapter 5 Functions and Performance

5-1

Chapter 5 Functions and Performance

The main functions of BTS30 will be introduced in the aspects listed: networking function, baseband processing, signaling processing and operation and maintenance.

5.1 Networking Function

The BTS30 allows for a flexible networking modes with many built-in transmission functions. It supports transmission modes such as E1, SDH.

5.1.1 E1 Networking

With one site as a basic unit, M900/M1800 BTS30 supports star, tree, chain and ring E1 networking topologies, which are illustrated in Figure 5-1.

BSC

BTS0

BTS1

BTS2

BSC BTS0

BTS1

BTS2

BTS3

BSC BTS0 BTS1 BSC BTS0 BTS1

star networking tree networking

ring networkingchain networking

Figure 5-1 The BTS30 E1 networking mode

Each TMU board provides 4 E1 interfaces and each cabinet can be configured with 2 TMU boards. If one interface is connected to the superior network, a maximum of 7 tributaries can be provided. A comparison between various connection modes is made in the following.

I. Star networking

Each site is connected directly to BSC by an E1 link, which brings very convenient maintenance and simple network construction.



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Signals pass through very few nodes, which means that no BTS depends on one another. So in the case of the failure of one BTS, other BTSs will not be affected.

This networking mode is usually applied in densely populated urban areas to facilitate easy expansion. But this type of networking requires a relatively large number of transmission links.

II. Tree networking

Tree networking has a complicated network structure. Signals pass through many nodes, i.e. any abnormality in the superior site will affect the subordinate sites, which leads to low line reliability.

This type of networking is applicable in vast sparely-populated areas density. But in such configuration, further expansion is quite difficult because it requires reconstructing of the network.

Since a BTS usually chooses the phase locking mode for the clock of its superior network and each time of choosing the phase locking will lead to the degeneration of clock quality, the number of BSC signals pass through should be restricted (the number of recommended serial connection layers is not more than five, i.e. the depth of the tree should not exceed five layers).

III. Chain networking

Along highways and railway tracks where the population density is very low, the most suitable networking is chain topology. But the problem lies in that in chain networking the signals pass through many nodes, resulting in poor link reliability. But for these areas, it has considerable advantages. It saves large quantity of transmission equipment.

Similar to the tree networking, the number of serial connection layers should be restricted and the number of the nodes that signals pass through should not exceed 5.

IV. Ring networking

Normally, the ring network is recommended because of its strong self-healing ability. If the optical fiber in a certain area is damaged, the ring network can be self healed into a chain network, without affecting services in any sense. The ring networking of BTS30 should be supported by ABA and ABB.

In practice a cellular network can have one or more than one network topology according to the actual physical and geographical requirements. So, considerable amount of transmission equipment investment can be saved and service quality can be ensured if the networking modes are applied correctly.



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5.1.2 SDH Networking

The BTS30 supports built-in transmission equipment. The ASU boards developed by Huawei are inserted in the common resource frame of the BTS30. The E1 on the BSC side can access the SDH network via Huawei’s OptiX155A transmission equipment.

Huawei's transmission equipment is adaptable to complex network structures under the support of its powerful cross-connect capability, abundant flexible interfaces, and advanced software functions.

As alternative optical transmission equipment of an extremely high performance/ price ratio in OptiX155/622A networking, ASU in actual networking can interwork with OptiX155/622A/B or Huawei's standard transmission equipment via the STM-1 optical interface. Besides, according to the transmission networking mode, it can form both ring and chain topologies.

A chain or ring network topology can be implemented depending on the distribution of the network routes. Normally, the ring network (as shown in Figure 5-2) is recommended because of its strong self-healing ability. If the optical fiber in a certain area is damaged, the ring network can be self healed into a chain network, without affecting services in any sense.

Normally in areas along railways and highways, chain networking is the most suitable solution (as shown in Figure 5-3). But even in such cases, if the distance between the stations is not too far (usually, the maximum distance between 3 stations 80km), and there are enough optical fibers (4 fibers), ring networking is still recommended.

TMU

ASU

ASU

ASU TMU

TMU

155ABSC

BTS0

BTS2

BTS1

E1

E1

E1

E1

Optical fiber

Optical fiberOptical fiber

Optical fiber

Figure 5-2 SDH ring networking



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BSC 155A ASU

TMU

ASU

TMU

BTS0 BTS1

E1E1

E1Opticalfiber

Opticalfiber

Figure 5-3 SDH chain networking

5.1.3 Networking for Satellite Transmission

In sparsely populated areas with poor transportation conditions, it is very hard and expensive to deploy land transmission network since common transmission technology and common BTS can hardly meet the requirements in such areas. So in these areas, satellite transmission is really a cost-effective and efficient solution. Figure 5-4 shows the networking for satellite transmission.

SDH/PDHor microwave/cable

E1

E1

MSC Ground station

BTS

BTS

BTS

BTS

Ground receive station

Ground receive station

BSC

Figure 5-4 Networking for satellite transmission

Networking for satellite transmission is now faced with technological difficulties, which is much related to some inherent features of satellite transmission, such as long transmission delay and poor stability of transmission links. These difficulties greatly



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constrains the promotion and application of satellite networking. To overcome these problems, Huawei offers an effective and complete solution as described in the following.

I. Solution to long transmission delay

Transmission delay at the Abis interface

During satellite transmission, there is a fixed delay of hundreds of milliseconds during the signaling control process on the Abis interface. To avoid timeout release of the activated call due to transmission delay, multiple timers are used for the signaling between BTS and BSC.

Handover

Due to the delay, the handover command issued from the BSC arrives at the BTS in hundreds of milliseconds, which leads to the degeneration of the voice quality of the mobile phone during this period. But in M900/M1800 BTS30, the functions of filtering, interleaving, PN judgement and prediction of the measurement report can be adjusted by setting parameters, and a special handover algorithm can be used to eliminate the impact of time delay.

TRAU time adjustment

Satellite transmission delay affects the alignment of the TRAU frames. As the delay in the common transmission modes is short, the TRAU frame adopts the simple fixed cyclic frame alignment. While in satellite transmission, the CCU (channel coder unit) adopts the self-adaptive alignment, which ensures that data can be aligned in a timely and correct manner in any delay amount, and that the transmission voice is of high quality.

II. Solution to synchronization problems

The synchronization between BTS and BSC can be greatly affected by the environmental factors which are stronger during satellite transmission, hence the voice quality will also be affected.

To solve this problem, the clock source at the BTS side adopts clocks of high accuracy and advanced APL algorithm. When BTS can synchronize with BSC, it will work in the synchronous mode.

III. Solution to bit errors

Bit errors will affect system synchronization, voice quality, initiation of calls, call connection and disconnection. So the reduction of bit errors must start with the satellite equipment.



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With measures implemented in both hardware and software design, Huawei's E-Abis interface technology has greater error tolerance capability and demonstrates excellent performance in error and jittery test, and in the actual running environment.

5.2 Main RF Function

The BTS30 RF functions meet the GSM 05.05 specifications. It is characterized by such advantages such as high sensitivity, flexible configuration, and convenient operation and maintenance. A brief description of the main RF functions is given below.

I. High receiving sensitivity

The receiving static sensitivity of the BTS30 is better than -109dBm (for 1800MHz), and -110dBm (for 900MHz). High sensitivity ensures the high uplink performance of the BS and it is also one of the preconditions for a better coverage of the BS.

II. Flexible configuration

The BTS30 can support 1~18 TRXs in each sector. The omni or sector cell (over 3 sectors) can be configured according to specific circumstances or the requirements of the operator. By adjusting the front end gain (such as the tower-top amplifier and the low noise amplifier), a BTS can also compensate the loss of feeders of different lengths, thus ensures the consistency in system receiving gain.

III. Convenient operation and maintenance

The RF unit of the BTS30 can be remotely controlled by the OMC to change transmitting power and transmitting frequencies. Alarm signals generated at the RF unit are reported to the OMC, so the operating personnel can observe and control the operation of the RF unit.

IV. Diversity receiving

The BTS30 provides diversity receiving function that is implemented by two independent receiving equipment, including antennas, tower top amplifier (optional), feeders, dividers, and receivers.

Both receivers demodulate received signals, which are then sent to the baseband processing unit for decoding by diversity algorithm. This diversity receiving function can provide 3~5dB diversity gain.

The application of diversity receiving technology enhances the anti-fading abilities of the base station receivers, so that the base station can maintain a good receiving performance even in complex radio environments.



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V. RF Hopping

Hopping is another important tool to enhance the performance of the base station. It enhances not only the anti-fading ability of uplinks and downlinks, but also the security of communication.

The BTS30 supports both frequency hopping and non-frequency hopping modes. When frequency hopping is required, the transceiver controlled by BSC can change its carrier frequency according to a hopping sequence which can be set through OMC. In non-hopping mode, the transceiver is locked at a certain frequency.

The frequency hopping of the BTS30 is realized through the real-time switchover between two frequency synthesizers. This implementation mode has two advantages, one is that the requirement about the rate of the frequency synthesizer can be reduced, the other is that one of the two frequency synthesizers can function as a backup to enhance the system reliability in non-frequency hopping mode.

Besides the traditional frame hopping, the BTS30 supports timeslot (TS) hopping, which further enhances the anti-fading ability.

VI. Power control

The BTS30 provides both static and dynamic power controls.

Static power control is used to adjust the service coverage range of BTS, i.e. it defines the coverage area of the cell. It has 0~10 power levels in step of 2dB.

When a mobile station moves and the distance to BTS changes, BSC can adjust BTS transmitting power according to the distances automatically. This process is called dynamic power control. It has 0~15 different power levels in steps of 2dB.

The power control at each level adopts automatic power closed-loop control (APC), which ensures a minimum power deviation.

When a timeslot is idle, as there are no downlink signals, BSC will send a command to BTS to shut down the transmitting power of this timeslot.

These power control functions can enhance the efficiency of transmitters, the reliability of power amplifier, and can also cut the interference of transmitters to the minimum.

5.3 Baseband Processing

The baseband processing unit mainly fulfills the functions of the physical layer on the Um interface, and processes all the full-duplex channel baseband data on a TDMA frame.



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At the transmitting end, it performs rate adaptation, channel encoding and interleaving, encryption, and the generation of TDMA bursts. At the receiving end, it is responsible for digital demodulation, decryption, de-interleaving, channel decoding and rate adaptation.

5.3.1 Channel Types Supported

The baseband processing unit supports the following channel types:

TCH/EFS: Enhanced Full-rate Speech Traffic Channel TCH/FS: Full-rate Speech Traffic Channel TCH/F9.6: Full-rate Data Traffic Channel (9.6kbits) TCH/F4.8: Full-rate Data Traffic Channel (4.8kbit/s) TCH/F2.4: Full-rate Data Traffic Channel ( 2.4kbit/s) FCCH: Frequency-Correction Channel SCH: Synchronization Channel BCCH: Broadcast Control Channel PCH: Paging Channel RACH: Random Access Channel AGCH: Access Grant Channel SDCCH/8: Standalone Dedicated Control Channel SACCH/C8: Slow Associated Control Channel/SDCCH/8 SACCH/TF: Slow Associated Control Channel/TCH/F FACCH/F: Fast Associated Control Channel/Full Rate SDCCH/4: Standalone Dedicated Control Channel/BCCH/CCCH SACCH/C4: Slow Associated Control Channel/SDCCH/4 CBCH: Cell Broadcast Channel

5.3.2 Channel Combinations Supported

The baseband processing unit supports the following types of channel combinations:

TCH/F+FACCH/F+SACCH/TF FCCH+SCH+BCCH+CCCH FCCH+SCH+BCCH+CCCH+SDCCH/4+SACCH/C4 BCCH+CCCH SDCCH/8+SACCH/8 SDCCH/8+SACCH/8+CBCH FCCH+SCH+BCCH+CCCH+SDCCH/4+SACCH/C4+CBCH Here CCCH=PCH+RACH+AGCH

5.4 Signaling Processing

The BTS30 signaling processing mainly fulfills:



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The interworking between MS and BSS/NSS on the Um interface. Management function of the radio resources under the control of the BSC.

The BTS30 signaling processing includes radio link management, dedicated channel management, common channel management and TRX management.

I. Radio link layer management procedures

Link establishment indication procedure: Through this procedure BTS indicates to the BSC that a multiframe data link has been established at the initiative of an MS. BSC can use this indication to set up an SCCP connection to MSC.

Link establishment request procedure: Through this procedure BSC request the setup of a multiframe data link on the radio channel.

Link release indication procedure: Through this procedure BTS indicates to BSC that a radio link has been released at the initiative of an MS.

Link release request procedure: Through this procedure BSC requests the BTS to release a radio link.

Transfer procedure of a transparent L3-message in acknowledged mode: Through this procedure BSC requests the BTS to send a transparent Um interface RIL3 message in acknowledged mode.

Receive procedure of a transparent L3-message in acknowledged mode: Through this procedure BTS indicates the BSC to receive a transparent Um interface RIL3 message in acknowledged mode.

Transfer procedure of a transparent L3-message in unacknowledged mode: Through this procedure BSC requests the BTS to send a transparent Um interface RIL3 message in non-acknowledged mode.

Receive procedure of a transparent L3-message in unacknowledged mode: Through this procedure BTS indicates the BSC to receive a transparent Um interface RIL3 message in non-acknowledged mode.

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

II. Dedicated channel management procedures

Channel activation procedure: Through which the BSC sends commands to BTS to activate a dedicated channel for a certain MS. After the activation, BSC assigns the channel to the MS through commands such as Immediate Assign, Assign Command, Additional Assignment or Handover commands.



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Channel mode modify procedure: This procedure is used by BSC to request BTS to change the mode of the activated channel.

Handover detection procedure: This procedure is used between the target BTS and target BSC to detect the handover access of MS.

Start ciphering procedure: Used for starting the ciphering procedure defined in TS GSM 04.08.

Measurement reporting procedure: It includes the necessary basic measurement reporting procedure and optional measurement reporting procedure with preprocessing. BTS reports all parameters related to handover decision to the BSC through it.

SACCH deactivation procedure: According to the requirements of channel release procedure specified in TS GSM 04.08, BSC uses this procedure to deactivate TRX related SACCH channel.

Radio channel release procedure: BSC uses this procedure to instruct BTS to release a radio channel, which is not in use state.

MS power control procedure: BSS uses this procedure to control the transmitting power of the MS related to a specific activated channel. MS power control decision must be implemented in BSC, and as an optional procedure in BTS.

Base station transmission power control procedure: BSS uses this procedure to control the transmission power of the activated channel in TRX. The base station transmitting power control decision should be implemented in BSC, or in BTS.

Connection failure procedure: BTS uses this procedure to indicate to BSC that an activated dedicated channel is already disconnected.

Physical environment content request procedure: BSC uses this procedure to obtain the physical parameters of a specific channel. This usually occurs before a channel change. This is an optional procedure.

SACCH information change procedure: BSC uses this procedure to instruct BTS to change the information (system information) filled in a specific SACCH channel.

III. Common channel management procedures

MS channel request procedure: This procedure is triggered when TRX detects random access ("channel request" message) from the mobile station.

Paging procedure: It is used to page information on a specific paging sub-channel. It is initiated by MSC and paged through BSC. 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.



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Immediate assignment procedure: When a mobile station accesses BTS, BSC uses this procedure to assign a dedicated channel for the mobile station immediately.

Deletion indication procedure: BTS uses this procedure to indicate to BSC that a RIL3-RR immediate assignment message is deleted (i.e., not put in the AGCH array) due to overloading of the AGCH channel.

CCCH load indication procedure: BTS uses this procedure to indicate to BSC the load on a specific CCCH channel.

Broadcast information change procedure: BSC uses this procedure to instruct the BTS to broadcast new system messages on the BCCH channel.

Short message cell broadcast procedure: BSC uses this procedure to request BTS to issue cell broadcast short messages.

IV. TRX management procedures

SACCH filling information change procedure: BSC uses this procedure to indicate BTS to use new system information on all downlink SACCH channels.

Radio resources indication procedure: BTS uses this procedure to indicate the interference level on each idle dedicated channel of TRX to BSC.

Traffic control procedure: FUC uses this procedure to indicate the overload condition of TRX to BSC, the cause may be CCCH overload, ACCH overload or processor overload.

Error reporting procedure: BTS uses this procedure to report the BSC about detected downlink message errors that can not be reported by other protocols.

5.5 Operation and Maintenance

The BTS30 also provides powerful operation and maintenance functions. It has four major functional modules, including the software loading, the configuration of object attributes of the base station, the equipment management and the operational status monitoring.

Software loading: BSC stores copies of software of all BTS boards. So when BTS operates for the first time after the installation, BTS successfully resets or BTS software is upgraded, the BSC will performs software loading to BTS.

Configuration management: including attributes configuration of such managed objects as sites, cells, radio carriers, and channels, as well as the management of Abis interface and transmission equipment.

Equipment management: including the detection of equipment switchover, resetting, and faults, performance testing, statistics measurement and status event reporting.



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Running status monitoring: including the monitoring and recording of various message flows, status conversion processes, and change of environment parameters during the operation of the base stations.

5.5.1 Software Loading

I. TMU software loading

After the power on or manual/auto restart of the TMU, it will request the BSC for the software version confirmation to ensure that the version acknowledged by the BSC is in operation. If the version number is incorrect, the BSC will load the correct version to the TMU.

All software loaded from the BSC to the TMU is stored in the Flash RAM of the TMU. When the BSC requests the activation, the TMU will execute the operation of the new software version.

II. Software loading from TMU to boards

After the manual/auto resetting, the board will send the software version confirmation request to TMU. TMU checks whether its version number is identical to that stored in the FLASH MEMORY. If it is, TMU will directly activate the version of this software. If it is not, TMU will load the version previously saved to the board, so as to ensure that the proper version is loaded and operating in this board. In addition, the BSC can also update the software version of the board through TMU.

The validity of the software is of great importance, therefore, both layer 2 and layer 3 have the checking and reloading system to guarantee high reliability.

III. Centralized management of software versions

To facilitate software updating, this function is provided to load software from BSC or MMI to the boards of BTS. As mentioned before, this function is implemented through the TMU. A TMU stores two versions of the software for the boards TMU, TBU (including SCP, CHDSP and EQDSP) and STU (including SCP and DSP), etc., and their version number is recorded respectively. The BSC or MMI can activate either of the two software versions to run or load new versions. The BSC or MMI can get the software version information of all the boards from the TMU, and display the information at the graphical interface.



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5.5.2 Abis Interface Management

I. Abis interface management

Abis interface is a standard interface between BTS and BSC, which takes the TS switching equipment as the main object of its management. It also involves the management of part of the data link layers.

The Abis interface management covers two aspects: the connection management of layer 1 and management of part of the signaling link layer. The Abis interface TS switching equipment of the BTS30 fulfills the switching between the E1 line and HW line inside the rack to accomplish the layer 1 connection of the link.

Signaling link connections should also be established on layer 2.

The Abis interface management has the following functions:

TEI set up (for both OML and RSL) Signaling channel connection set up Signaling channel disconnection Traffic channel connection set up Traffic channel disconnection

II. Transmission management

Transmission here refers to the cascade transmission of E1 signals. As both the BTS30 E1 transmission and the Abis timeslot switching are carried out by BIU, implementation of this function is similar to that of Abis interface management. Link connection on layer 1 is set up by changing the timeslot switching configurations between BIU and E1 lines.

One BSC normally can carry multiple SITEs. Between BSC and SITEs, multiple connection modes are supported, such as star, chain, tree, ring and hybrid networking. Except star networking, all other modes involve the cascade management of E1 signals, i.e., forwarding traffic and signaling to subsequent sites.

The ring connection mode also involves loop management.

Transmission management has the following functions:

Multi-point connection set up Multi-point connection deletion Ring connection set up Ring connection deletion



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5.5.3 Air Interface Management

The air interface management mainly involves the parameter configuration that determine the physical channel and the logical channel of the air interface, including the configuration of the attributes of the cell, carrier frequency and transmission channels.

The physical channel parameters of the air interface mainly include the carrier and the timeslot parameters, which are configured according to the carrier attributes.

The logical channel parameters mainly include the channel types, and the messages appeared on them, especially the system message, which are determined by the attributes of both the channel and the cell.

I. BTS attributes setting

BTS attributes refer to the parameters applicable to the whole cell, but not related to specific carriers and channels, including:

1) Interference level limit 2) Interference average value 3) Connection failure decision threshold: the BER or the receiving level threshold. 4) T200, including the T200 timing values of the following channels:

SDCCH FACCH (full rate) FACCH (half rate) SACCH (relevant to TCH, SAPI=0) SACCH (relevant to SDCCH) SDCCH (SAPI=3) SACCH (relevant to TCH, SAPI=3)

5) Maximum timing advance 6) Overload indication period 7) CCCH load threshold 8) CCCH load indication period 9) RACH busy decision threshold 10) RACH load average TS number 11) BTS air timer 12) Maximum number of physical channel message retransmissions (Ny1) 13) BCCH absolute RF number 14) Base station identification code (BSIC) 15) Configuration start time



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II. Carrier frequency attributes setting

The carrier frequency attributes are the parameters relevant to the specific carrier frequency, which include:

Maximal power descending of the RF RF absolute channel numbers table

III. Channel attributes setting

The channel attributes refer to the parameters related to the specific channel, including:

Channel combination mode Frequency hopping serial number Mobile allocation index offset (MAIO) RF absolute channel numbers table Configuration start time Training sequence number

IV. Air interface management extension

The operation and maintenance protocol of the base stations is mainly stipulated in GSM 12.21 standards. This protocol is not yet perfect, and should be extended in actual applications.

The BTS30 protocol extension includes two aspects: the setting of BTS extended attributes (frequency hopping modes etc.), and the setting of sites extended attributes, including environment parameters and clock hardware parameters (phase locking reference source, DAC values).

5.5.4 Testing Management

Testing management is an important function of the base station maintenance. With the help of this function, the user can determine and locate the fault in BTS. During the normal operation of a base station, periodic tests should also be carried out over certain items to trace the performance of the base stations and to predict the possible faults of base stations.

It must be noted that with the increasing of base station maintenance functions, demands for testing functions become more stringent, which constitutes one of the most extendable parts of operation and maintenance functions.

The BTS30 provides powerful testing functions with a large variety of test items provided, mainly including:

1) TRX Abis link testing 2) Free burst testing



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3) E1 self-loop testing 4) Functional object self-test, including:

Site self-test Cell self-test TRX self-test Board self-test

5.5.5 Status Management

The status of various logical objects and physical objects of the base station is stored in 3 entities, i.e., BSC, TMU, and boards. The correctness and consistency of states stored in these 3 entities is one of the basic conditions for the normal operation of the base station.

The base station status management mainly involves 3 kinds of status: management status, operation status, and availability status. Management status is required to remain consistent from top to bottom, i.e., from BSC, TMU to boards, while operation status is required to remain consistent from bottom to top. Availability status is the specific explanation of operation status.

Consistency of these 3 kinds of states is vitally important, for inconsistency will result in resources waste as some available channels might not be distributed, or abnormal service provision occurs due to possible distribution of damaged channels.

TMU monitors the setup and disconnection of various communication links, and checks the status of the boards in realtime. If any change occurs, it will immediately report the change to BSC and MMI, and display it through the OMC.

5.5.6 Processing of Event Reports

Event report mainly refers to the report of internal base station errors, or fault reports generated during alarming.

Considering the importance of such reports, it must be ensured that each command and report reaches the destination and is correctly explained, i.e., there must be a response mechanism. The response mechanism from top to bottom is stipulated in GSM protocol 12.21, but the response mechanism from bottom to top is not yet specified in the protocol. For the sake of simplicity and to save command codes, the upward reports are directly returned as responses.

A base station can be managed through BSC and MMI. For inquiry operations, both can perform the operations simultaneously. For operations that may change the running status of the base station (e.g., parameters setting), only the one with the management authority can perform such operations. By default, BSC enjoys the management authority.



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To obtain the management authority, MMI must first send to BSC a management status changing request. After BSC confirms the request, it will issue a management status changing command, so as to shift the management authority to MMI. When MMI operation ends, it must request BSC to take back its management authority.

The BTS30 may involve two kinds of alarms: board alarms and environment alarms.

I. Board alarms

When any board alarm occurs or disappears, the board reports it to TMU, and TMU will report it to BSC or MMI immediately. According to the cause, an alarm may be classified into one of the following categories:

Transmission and communication alarms: This mainly refers to an out-of-synchronization alarm of either the local end or remote end of E1 port, or loop interruption alarm.

Clock alarms: various kinds of clock source alarms and TBPU clock alarms.

Power supply alarm: over/under voltage alarms of power supply of the carrier part and power supply fault alarms.

General alarms: hardware faults of various boards, internal bus alarms, and software running errors.

After receiving alarm messages from a board, TMU will take the corresponding measures according to the alarm severity. For a critical alarm, immediate measures will be taken to reduce any possible damage, such as resetting the board or switching off the carrier power supply, etc.

TMU reports all the alarms to BSC and MMI to display them at the graphic interface.

II. Environment alarms

Environment alarms (including fire, smog, intruder, water, temperature and humidity etc.) are collected by the environment monitoring instrument. On receipt of an alarm, TMU will activate the attached device(s) through the alarm box, such as air-conditioner, fire-extinguisher, smoke-removing devices, and dehumidifier. Also, it will report it to BSC and MMI for it to be displayed at the graphic interface.

5.5.7 Equipment Management

I. Equipment switchover

To guarantee the system reliability, the BTS30 provides active/standby configuration for important components. In case of any abnormality in the active boards, the system can shift the service to the standby boards automatically or manually.



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In addition, the BSC can send a switchover command to perform switchover on the object desired. When a board receives a switchover command from BSC, activated by this command, it directly receives commands from the TMU to initiate switchover. Otherwise, the switchover is initiated by the board itself, and will be directly reported after the switchover.

II. Operation starting

The operation of the equipment involves the steps and synchronization during the starting. The operation starting function is used to start the equipment at the proper time.

III. Re-initialization

In some cases, the running object may require re-initialization, which is mostly caused by the failure of the equipment or the need to reconfigure large quantity of data. And it can be initiated by the command from BSC via TMU.

IV. Configuration of site output (external devices)

There may be some external devices for each BTS, such as air-conditioner, dehumidifier, humidifier, and controllable camera etc. The controlling over these devices can be regarded as output variables.

V. Power supply management commands

When some critical faults occur to carrier equipment, such as too high temperature or standing wave ratio exceeding the threshold, make the equipment quit serving any more or power off the carrier part (including the power amplifier) so as to prevent it from being completely damaged. In case of mains power supply failure, the base station can turn off some TRXs, and keep only the BCCH carrier working to handle the necessary data so as to reduce the voice services and prolong the service of standby power supply.

VI. Software and hardware version's query

During the maintenance, for example, when the software is being updated, usually the software and hardware version number shall be checked. After TMU is started, the software and hardware version number shall be read so as to upgrade the database for future query, and to judge whether the version number is identical with the configuration or not.



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VII. Board re-initialization after resetting

After being reset, boards will request for re-initialization. The re-initialization process is to configure the required parameters first, and then restart the board.

VIII. Processing of board and environment alarms

Base station alarms mainly includes two types: board alarms and environment alarms. When there is any abnormality in board itself or its resources, a board running failure alarm will be reported to TMU. Environment alarms are collected by TMU and alarm box. TMU reports all alarm messages timely to BSC and take necessary emergency processing measures.

5.5.8 Site Configuration

I. Configuration of logical parameters

The configuration of site logical parameters is to determine such basic site configuration parameters as the number of sectors, baseband processing units and carrier units etc. Logical units can be added or deleted during future network expansion or network optimization.

II. Configuration of physical boards

Site physical board configuration is to configure, add or delete given boards for sites in configuration tables.

5.5.9 Tracing Operations

I. Interface tracing

It is usually necessary to trace various interface messages during operation, for the sake of convenient debugging, detecting and locating of faults occurred during normal operation.

The interfaces now available for tracing include various interfaces between the TMU layer 3 and its lower levels, and the air interface (Um interface). What's more, other interfaces can be added to the tracing list for the sake of convenient debugging.

II. Resource tracing

The resource utilization conditions are the important parameters for analyzing the program efficiency and status, and important indexes for testing whether the system



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meets the requirements or not. Resource tracing can be started or stopped according to the actual need to adjust the traffic flow.

III. System logs

To keep system operation process records is one of the best way to trace the errors. The TMU software log mainly keeps two types of information: one is the interface message mentioned above, and the other is the program running errors. The board log is reported to the TMU, from which it is transferred transparently to the BSC or saved in the log buffer area.

5.5.10 Other Functions

I. Attributes query

Most of the attributes of managed objects are configured by the BSC during base station initialization, and part of them may be modified during the operation. Any of the attributes can be queried during maintenance, which is helpful to decide the operation status of the base station.

II. Alarm threshold setting

Different threshold values can be set through OMC for the protection of different objects so as to avoid system down. For example, alarm limits can be set on the RF working power and the standing-wave ratio etc.

III. OML link test

In order to guarantee the proper operation of OML link and to supervise its status, the BSC transmits some routine messages to the TMU to supervise this link. In addition, the BSC realtime clock is also transmitted, which is used as the TMU superior level clock reference.

IV. Transparent commands

For debugging convenience and adding of new functions, transparent commands can be used to flexibly transfer some customized commands or debugging commands to some designated boards.

V. Query on-site board

The on-site board refers to the board which has been installed in the slot and hasn’t been configured on the data configuration console. This kind of boards can be queried on the board maintenance panel and are differentiated by color.



5-21

5.6 System Indices

I. Power consumption

Test conditions: temperature: 25C; relative humidity: 80%; power amplifier power output: 40W. Measured at the inlet of the cabinet power supply (the output of the primary power supply) 30 minutes after the power-on and normal working of the system.

The power consumption of the cabinet in different configurations are listed in Table 5-1.

Table 5-1 Power consumption of the BTS30 in different configurations

Number of TRXs Voltage (V) Current (A) Power consumption (W)

6 26.8 44.3 1187

5 26.8 37.8 1013

4 26.8 31.2 836

3 26.8 24.7 662

2 26.8 17.2 461

1 26.8 10.7 287

II. Clock

Frequency: 1.3×107 Hz, with the precision upon leaving the factory better than 0.1 Hz.

Frequency deviation varied with temperature changes: < ± 0.05 ppm (temperature from 0C to 70C). Annual aging rate: < ± 0.1 ppm.

III. Environmental conditions

Since the BTS30 is an indoor base station, the automatic air-conditioning system is required in the room.

It can work smoothly within the temperature range -5C~+45C under 15-85% relative humidity.

The environmental alarm box is available to supervises the environmental parameters and report the alarms.



5-22

IV. System reliability

Table 5-2 The mean time between failures (MTBF) of BTS30

No. Cell configuration Failure rate accumulated (10-6h) MTBF(h)

1 O(1) 37.452 35000

2 O(2) 33.996 30000

3 S(2/2/2) 56.560 18000

4 S(4/4/4) 75.414 15000

5 S(6/6/6) 97.834 11000

V. Physical characteristics

Dimensions: 1600 mm (H) × 600 mm (W) × 450 mm (D).

Weight: Empty cabinet 85 kg.

Fully configured cabinet 180kg.

5.7 Radio Interface Indices

I. The functional frequencies of M900 BTS30

Uplink (MHz) Downlink (MHz)

Primary band 890-915 935-960

II. The functional frequencies of M1800 BTS30

Up Link (MHz) Down Link (MHz)

Primary band 1710-1785 1805-1880

5.7.1 Receivers

I. Receiving sensitivity

Testing conditions: FCH/FS channel, no frequency hopping, BER and frame deletion rate meet the requirements of Table 1 of GSM 05.05 standards.

1) M900 BTS Static sensitivity: better than -110dBm. Multipath sensitivity: better than -104dBm under TU3, TU50, RA250 and HT100

transmission conditions.



5-23

2) M1800 BTS Static sensitivity: better than -109dBm. Multipath sensitivity: better than -104dBm under TU3, TU50, RA250 and HT100

transmission conditions.

II. Receiver input level range

1) M900 BTS

In the static transmission condition, the relationship between the input levels and the M900 BTS Type II BER measured on the TCH/FS channel is given in Table 5-3:

Table 5-3 Relationship between the M900 BTS Type II BER and input levels

Input level range Static sensitivity level~-84dBm -84dBm~-40dBm -40dBm~-15dBm

Type II BER <2 % <10-4 <10-3

2) M1800 BTS

In the static transmission condition, the relationship between input levels and M1800 BTS Type II BER measured on the TCH/FS channel is given in Table 5-4:

Table 5-4 Relationship between the M1800 BTS Type II BER and input levels

Input level range Static sensitivity level~-84dBm -84dBm~-40dBm -40dBm~-23dBm

Type II BER <2 % <10-4 <10-3

III. Blocking features

1) M900 BTS

When the sine wave interference signals with frequency and level as shown in Table 5-5 are input together with the -101dBm useful signals into the M900 BTS receiver, the BER still meets the requirements.

Table 5-5 Frequency and level of M900 BTS sine wave interference signals

Frequency (inband) 600kHz |f-f0|<800kHz 800kHz |f-f0|<3.0MHz 3.0MHz |f-f0|

Level (dBm) -26 -16 -13

Frequency (outband) 0.1MHz f<870MHz 925MHz f<12750MHz

Level (dBm) 0 0

Where f0 is the useful signal frequency, and f is the interference signal frequency.



5-24

2) M1800 BTS

When the sine wave interference signals with frequency and voltage level as shown in Table 5-6 are input together with the -101dBm useful signals into the M1800 BTS receiver, the BER still meets requirements

Table 5-6 Frequency and level of M1800 BTS sine wave interference signals

Frequency (inband) 600kHz |f-f0|<800kHz 800kHz |f-f0|<3.0MHz 3.0MHz |f-f0|

Level (dBm) -35 -25 -25

Frequency (outband) 0.1MHz f<1690MHz 1805MHz f<12750MHz

Level (dBm) 0 0

Where f0 is the useful signal frequency, and f is the interference signal frequency.

IV. C/I and bit error code rate

When the useful signal is -84dBm, relationship between the TCH/FS channel TYPE II BER and C/I measured under the non-hopping multipath condition is shown as in Table 5-7. This relationship in M900 is the same as that in M1800.

Table 5-7 Relationship between the BTS TYPE II BER and C/I

Interference frequency C/I(dB) TCH/FS TYPE II BER

f = f0 9 TU1.5 RBER<4.0%

| f - f0| = 200kHz -9 TU50 RBER<8.1%

| f - f0| = 400kHz -41 TU50 RBER< 8.1%

f is the random continuous GSM modulated interference signal frequency, and f0 is the useful signal frequency.

V. Inter-modulation response suppression

1) M900 BTS

For M900 BTS, when the useful signals with a sensitivity 3dB higher than the reference sensitivity are input to the receiver simultaneously with two -43dBm interference signals, the TYPE II BER measured on the TCH/FS channel is better than 2%, and the carrier relationship and modulation forms of interference signals satisfy GSM 11.21 specifications.

2) M1800 BTS

For M1800 BTS, when the useful signals with a sensitivity 3dB higher than the reference sensitivity are input to the receiver simultaneously with two -49dBm



5-25

interference signals, the TYPE II BER measured on the TCH/FS channel is better than 2%, and the carrier relationship and modulation forms of interference signals meet GSM 11.20 specifications.

VI. Stray radiation

The testing result is the same for both M900 BTS and M1800 BTS:

Radiation within 9kHz~1GHz: <-57dBm Radiation within 1GHz~12.75GHz: <-47dBm

5.7.2 Transmitters

I. Average carrier frequency power

For M900 BTS and M1800 BTS, the average carrier frequency power of the transmitter measured at the combiner input end is 46dBm with a tolerance of ±1dBm.

II. Power Control

1) Static power control

Both the M900 BTS and M1800 BTS transmitters have 10 levels for static power adjustment, with a step length of 2±1dB. On each static power level, the absolute precision is better than ±3dB.

2) Dynamic power control

Both the M900 BTS and M1800 BTS transmitters have 15 levels for dynamic power adjustment, with a step length of 2±1.5dB. On each dynamic power level, the absolute precision is better than ±3dB.

III. Carrier frequency envelope

Power flatness of the 147 bit useful part: <±1dB.

Cutoff timeslot power: <-30dBc.

The ramping up and down of the power bursts is in accordance with the power-versus-time template (Figure 5-5).



5-26

+4+1-1-6

-30

10 8 10 10 8 10542.8t(us)

dB

Figure 5-5 Power-versus-time template

Note: Testing results are the same for both M900 and M1800 BTSs.

IV. Transmission spectrum

1) Modulated spectrum

Power of various deviating frequency points of M900 and M1800 BTSs are shown in Table 5-8 and Table 5-9 respectively.

Table 5-8 Power of various deviating frequency points of M900 BTS

Frequency deviation 100kHz 200kHz 250kHz 400kHz 600kHz

~1.2MHz 1.2MHz ~1.8MHz

1.8MHz ~6MHz ƒ6MHz

Max. power level (dBc) at relative carrier

0.5 -30 -33 -60 -70 -73 -75 -80

Table 5-9 Power of various deviating frequency points of M1800 BTS

Frequency deviation 100kHz 200kHz 250kHz 400kHz 600kHz

~1.2MHz 1.2MHz ~1.8MHz

1.8MHz ~6MHz ƒ6MHz

Max. power level (dBc) at relative carrier

0.5 -30 -33 -60 -70 -73 -75 -80

2) Transient spectrum

For M900 and M1800 BTSs, the power levels caused by handover at the various deviating frequency points are shown in Table 5-10 and Table 5-11 respectively.



5-27

Table 5-10 Power levels of M900 BTS caused by handover at various deviating frequency points

Frequency deviation 400kHz 600kHz 1.2MHz 1.8MHz

Maximum power level (dBc) of relative carrier -57 -67 -74 -74

Table 5-11 Power levels of M1800 BTS caused by handover at various deviating frequency points

Frequency deviation 400kHz 600kHz 1.2MHz 1.8MHz

Maximum power level (dBc) of relative carrier -50 -58 -66 -66

V. Intermodulation suppression

1) M900 BTS

For interference signals coming from the antenna into the transmitter, the intermodulation signal suppression of the transmitter is over 70dBc (or under -36dBm), and the levels of the 3rd order and 5th order intermodulation signals falling within the 890~915MHz frequency band are under -98dBm.

The suppression of the intermodulated signal after multi-carrier combination is over 70dBc (or under -36dBm) when it falls within the 935MHz~960MHz frequency band, and that falling within the 890MHz~915MHz frequency band has an output level under -98dBm.

2) M1800 BTS

For interference signals coming from the antenna into the transmitter, the intermodulation signal suppression of the transmitter is over 70dBc (or under -36dBm), and the levels of the 3rd order and 5th order intermodulation signals falling within the 1710~1785MHz frequency band are under -98dBm.

The suppression of the intermodulated signal after multi-carrier combination is over 70dBc (or under -36dBm) when it falls within the 1805MHz~1880MHz frequency band, and that falling within the 1710MHz~1785MHz frequency band has an output level under -98dBm.

VI. Spurious emission

Conductive stray radiation measured at antenna connection points meets the following requirements:

1) M900 BTS 9kHz~1GHz: <-36dBm 890MHz~915MHz: <-98dBm



5-28

1GHz~12.75GHz: <-30dBm 2) M1800 BTS

9kHz~1GHz: <-36dBm 1710MHz~1785MHz: <-98dBm 1GHz~12.75GHz: <-30dBm

VII. Frequency deviation and phase deviation

Transmitting signal frequency deviation: <0.05ppm

Transmitting signal phase deviation: <5°(rms)

<20° (peak)

Note: For M900 BTS and M1800 BTS, the testing results are same.


System DescriptionChapter 6 Configuration and Typical Application

6-1

Chapter 6 Configuration and Typical Application

6.1 Configuration

We have already discussed that the BTS30 offers a variety of networking options and can be configured flexibly in different network topologies according to the user requirements. In the following chapter we will discuss the configuration of the BTS30 from several aspects.

6.1.1 Cell Configuration

Synchronous cells can be defined as cells that are using the same clock source carriers. A synchronous cell can be an omni cell, or a group of sectors. The BTS30 can support the following synchronous cell configurations:

Synchronous omni cell, 1~18 TRXs. Synchronous 2 sector-cell, 1+1~18+18 TRXs. Synchronous 3 sector-cell, 1+1+1~18+18+18 TRXs. Over-3-sector cells if required by customer.

A single BTS30 cabinet of the BTS30 may contain a maximum of 6 TRXs. A synchronous cell with more than 6 TRXs can be configured in more than one cabinets, which can be called "combined cabinet configuration". Combined cabinet configuration means that one basic cabinet supports (maximum) one extension cabinet, and the cabinets are connected via clock cables, O&M cables, etc.

In combined cabinet configuration, the cabinet with TMU board is called the "basic cabinets", and the cabinet without TMU board is called the "extension cabinet".

The extension cabinet and the basic cabinet share the same TMU board. Clock, data, and maintenance & operation signals required by the extension cabinet are sent via cables from the basic cabinet to the extension cabinet.

One basic cabinet, or 1 basic cabinet plus 1~2 extension cabinets, is called a cabinet group.

Each cabinet group can support a maximum of 18 TRXs. When the number of TRXs in a synchronous cell exceeds 18, multiple cabinet groups can be configured.

The cabinet group which provides the cell clock source is called the "basic cabinet group". In the basic cabinet group, the basic cabinet has 2 TMU boards. Other cabinet groups are called "extension cabinet groups" and 1 or 2 TMU boards can be configured in the basic cabinet of each extension cabinet group.



6-2

Clock and maintenance operation signals are sent via cables from the basic cabinet of the basic cabinet group to the basic cabinet of the extension cabinet group, and then from the basic cabinet of each cabinet group to the extension cabinet of this cabinet group.

Cabinet (group) configuration should observe the following rules:

When there are less than 6 TRXs in a synchronous cell, one cabinet is configured for this cell. When there are over 6 but less than 18 TRXs in a synchronous cell, combined cabinets are configured for this cell.

When there are over 18 TRXs in a synchronous cell, combined cabinet groups are configured for this cell.

Configuration of combined cabinets or cabinet groups should obey the following rules:

The minimum antenna rule, i.e., to use as few as possible antennas for cell configuration.

The minimum cabinet rule, i.e., to use as few as possible cabinets for cell configuration.

The complete synchronous sector rule, i.e., all TRXs of a synchronous sector are configured in the same cabinet group.

The basic cabinet priority rule, i.e., TRXs are configured in the basic cabinet in preference, and the number of TRXs in the basic cabinet is not less than that in any extension cabinet.

6.1.2 Configuration of the Common Resource Frame

The common resource frame in the basic cabinet of the basic cabinet group contains 4 PSUs, 1 PMU, 2 TMUs, 1 TEUs and 1 TES. The common frame in the basic cabinet of the extension cabinet group contains 4 PSUs, 1 PMU, 1 or 2 TMUs, 1 TEU and 1 TES.

In the common frame of the extension cabinet, only 4 PSUs and 1 PMU are configured, TEU and TES are optional.

The full configuration of the common resource frame is shown in Figure 6-1.

P S U

P S U

P S U

P S U

P M U

T MU

T MU

T E S

T E U

Figure 6-1 The common frame in full configuration



6-3

6.1.3 Configuration of the TRX Frame

A TRX frame has 6 TRX positions. When TRX units in a single cabinet are less than 6, the carriers are arranged from left to right. The TRX frame in full configuration is shown in Figure 6-2.

T R X

T R X

T R X

T R X

T R X

T R X

Figure 6-2 TRX frame in full configuration with TRX

When the much coverage is needed, the PBUs can be configured in the frame. The TRX frame in full configuration with TRX and PBU is shown in Figure 6-3.

P B U

T R X

P B U

T R X

P B U

T R X

Figure 6-3 TRX frame in full configuration with TRX and PBU

6.1.4 Full Configuration of CDU Frame

The BTS30 cabinet has 3 slots for CDUs, so in the full configuration 3 CDUs can be used. Single CDU is required for 1 to 2 carriers, two CDUs for 3 to 4 carriers, and three CDUs are required for 5 to 6 carriers configuration, as shown in Figure 6-4.

In some configurations, SCU might be used.

C D U

C D U

C D U

Figure 6-4 Front view of CDU frame configuration

EDU and SCU might be used in some configurations. Configuring an EDU may reduce the combining loss of RF signals and enhance the coverage of the base station. In the case of hot spot coverage, configuring an SCU may reduce the number of CDUs needed and thus lower the costs.



6-4

6.1.5 Configuration of the Antenna

I. Antenna

Each site can be configured with one omni cell or multiple directional cells (sectors). When each cell has no more than 4 TRXs, two sets of antennas are used, one antenna is used as diversity antenna. When the carriers in a cell are more than 4, one more antenna is needed. The dual polarization antennas can also be used to reduce the total number of antennas.

II. RF cable set

RF cable set refers to the RF cables from the combiner and divider unit to the top of the cabinet and to TRX or PBU. From the combiner and divider unit to the top of the cabinet, 1/4-inch super-flexible cables are used. While the receiving and transmitting cables from the combiner and divider unit to TRX or PBU are all half-flexible cables. The number of cables is usually related with TRX configuration.

6.2 Typical Configuration

This section discusses some typical configurations, including S (2) (one sector-cell, configured with 2 TRXs), S (2/2/2) (three sector-cell, each cell configured with 2 TRXs), O (3) (one omni cell, configured with 3 TRXs), and O (4).

6.2.1 S(2) Configuration

I. Configuration of antenna components

Antennas

Each sector is configured with 2 sets of single polarization antennas. Or, each sector is configured with one set of dual polarization antenna.

RF cable set

The BTS30 S (2) configuration cables are used.

II. Cabinet configuration

Only one cabinet is needed for S (2) configuration, as shown in Figure 6-5.



6-5

FAN BOX

T

E

U

T

E

S

T

M

U

T

M

U

SWITCH BOX

AIR BOX

P

S

U

P

S

U

P

S

U

P

M

U

T

R

X

T

R

X

TDU

E

D

U

Note: Boards with slashes in the diagram are optional.

Figure 6-5 S(2) cabinet configuration

6.2.2 S(2/2/2) Configuration


Antennas

Each cell is configured with 2 sets of single polarization antennas, So in total 6 antennas are needed for 3 cells. Or, each cell is configured with one set of dual polarization antenna, and 3 antennas are needed for 3 cells.



6-6

RF cable set

The BTS30 S (2/2/2) configuration cables are used.


Only one cabinet is needed for S (2/2/2) configuration, as shown in Figure 6-6.

FAN BOX

T

E

U

T

E

S

T

M

U

T

M

U

SWITCH BOX

AIR BOX

P

S

U

P

S

U

P

S

U

P

S

U

P

M

U

T

R

X

T

R

X

T

R

X

T

R

X

T

R

X

T

R

X

C

D

U

C

D

U

C

D

U

TDU


Figure 6-6 S(2/2/2) cabinet configuration



6-7

6.2.3 O (3) Configuration


Antenna

The cell is configured with one set of omni antenna.

RF cable set

The BTS30 O (3) configuration cables are used.


The cabinet configuration is shown in Figure 6-7.

FAN BOX

T

E

U

T

E

S

T

M

U

T

M

U

SWITCH BOX

AIR BOX

P

S

U

P

S

U

P

S

U

P

M

U

T

R

X

T

R

X

T

R

X

S

C

U

C

D

U

TDU


Figure 6-7 O(3) cabinet configuration



6-8

6.2.4 O(4) Configuration


Antenna

The cell is configured with one set of omni antenna.

RF cable set

The BTS30 O(4) configuration cables are used.


The cabinet configuration is shown in Figure 6-8.

FAN BOX

T

E

U

T

E

S

T

M

U

T

M

U

SWITCH BOX

AIR BOX

P

S

U

P

S

U

P

S

U

P

S

U

P

M

U

T

R

X

T

R

X

C

D

U

TDU

P

B

U

P

B

U

FAN BOX

T

E

U

T

E

S

T

M

U

T

M

U

AIR BOX

P

S

U

P

S

U

P

S

U

P

S

U

P

M

U

T

R

X

T

R

X

C

D

U

P

B

U

P

B

U

TDU


Figure 6-8 O(4) cabinet configuration


System DescriptionAppendix A Abbreviations

A-1

Appendix A Abbreviations

A

AB Access Burst

ACCH Associated Control CHannel

ACU Alternating Current Unit

AGCH Access Grant CHannel

AI Action Indicator

ARFCN Absolute Radio Frequency Channel Number

B

BA BCCH Allocation

BCC Base Transceiver Station (BTS) Color Code

BCCH Broadcast Control CHannel

BER Bit Error Ratio

BFI Bad Frame Indication

Bm Full-rate traffic channel

BP Burst Period

BSC Base Station Controller

BSIC Base transceiver Station Identity Code

BSS Base Station Sub-System

BSSAP Base Station Sub-System Application Part

BSSMAP Base Station Sub-System Management Application Part

BSSOMAP Base Station Sub-System Operation and Maintenance Application Part

BTS Base Transceiver Station

BTSM BTS Management

C

CA Cell Allocation

CBCH Cell Broadcast CHannel

CC Call Control

CCCH Common Control CHannel

CCH Control CHannel

CDU Combiner and Divider Unit



A-2

CM Connection Management

CMB Common resource Backplane

C/R Command/Response field bit

CRC Cyclic Redundancy Check (3 bit)

CUI Carrier Unit Interface Controller

D

DB Dummy Burst

DCCH Dedicated Control CHannel

DCL Diagnostic Control Link

DCU Direct Current Unit

DL Data Link (layer)

DLCI Data Link Connection Identifier

Dm Control channel

DRX Discontinuous reception (mechanism)

DTAP Direct Transfer Application Part

DTX Discontinuous transmission (mechanism)

E

EAC External Alarm Collection

ETS European Telecommunication Standard

ETSI European Telecommunications Standards Institute

F

FACCH Fast ACCH

FACCH/F Fast Associated Control Channel/Full rate

FB Frequency correction Burst

FCCH Frequency Correction CHannel

FCS Frame Check Sequence

FH Frequency Hopping

FN Frame Number

FU Frame Unit

G

GMSC Gateway Mobile-services Switching Centre

GMSK Gaussian Minimum Shift Keying (modulation)

GSM Global System for Mobile communications

H



A-3

HDLC High level Data Link Control

HLR Home Location Register

HPA High magnification Power Amplifier board

HSN Hopping Sequence Number

I

ID Identification/IDentity

IE Signalling information element

IF Information Frame

IMEI International Mobile station Equipment Identity

IMSI International Mobile Subscriber Identity

ISDN Integrated Services Digital Network

ISUP ISDN User Part (of signalling system No.7)

IWF Interworking Function

L

L1 Layer 1

L2 Layer 2

L2ML Layer 2 Management Link

L3 Layer 3

LA Location Area

LAPB Link Access Protocol Balanced

LAPD Link Access Protocol on the D channel

LAPDm Link Access Protocol on the Dm channel

Lm Half rate traffic channel

M

MA Mobile Allocation

MACN Mobile Allocation Channel Number

MAI Mobile Allocation Index

MAIO Mobile Allocation Index Offset

MAP Mobile Application Part

MCK Main Clock board

MM Mobility Management

MMI Man-Machine Interface

MPH Management entity - Physical layer [primitive]

MS Mobile Station



A-4

MSC Mobile-services Switching Centre, Mobile Switching Centre

MSISDN Mobile Station International ISDN Number

MTP Message Transfer Part

N

NB Normal Burst

NM Network Management

O

OCXO Oven voltage Control Oscillator

O&M, OM Operations & Maintenance

OMC Operations & Maintenance Centre

OML Operations & Maintenance Link

OSI Open System Interconnection

OSI RM OSI Reference Model

P

PAD Packet Assembly/Disassembly facility

PAU Power Amplifier Unit

PCH Paging CHannel

PCM Pulse Code Modulation

PH Physical (layer)

PLMN Public Land Mobile Network

PMU Power Monitor Unit (board)

PP Point-to-Point

PSTN Public Switched Telephone Network

PSU Power Supply Unit

R

RACH Random Access CHannel

RBER Residual Bit Error Ratio

RCU Receiver Unit

RFN Reduced TDMA Frame Number

RIL3 Radio Interface Layer 3

RNTABLE Table of 128 integers in the hopping sequence

RPU Radio frequency Process Unit

RR Radio Resource management

RSL Radio Signalling Link



A-5

RSM(RR') Radio Sub-system Management

RXLEV Received signal level

RXQUAL Received Signal Quality

S

SABM Set Asynchronous Balanced Mode

SACCH Slow Associated Control CHannel

SACCH/C4 Slow Associated Control CHannel/SDCCH/4

SACCH/C8 Slow Associated Control CHannel/SDCCH/8

SACCH/T Slow Associated Control CHannel/Traffic channel

SACCH/TF Slow Associated Control CHannel/Traffic channel Full rate

SAP Service Access Point

SAPI Service Access Point Indicator

SB Synchronization Burst

SCCP Signalling Connection Control Part

SCH Synchronization CHannel

SCN Sub-Channel Number

SCU Simple combining Unit

SDCCH Stand-alone Dedicated Control CHannel

SFH Slow Frequency Hopping

SID Silence Descriptor

SIM Subscriber Identity Module

SMS Short Message Service

SMSCB Short Message Service Cell Broadcast

SS Supplementary Service

STU Site Test Unit (board)

T

TA Timing Advance

TBU Transceiver Baseband Unit

TC Transcoder

TCH Traffic CHannel

TCH/F A full rate TCH

TCH/F2.4 A full rate data TCH (2.4kbit/s)

TCH/F4.8 A full rate date TCH (4.8kbit/s)

TCH/F9.6 A full rate data TCH (9.6kbit/s)



A-6

TCH/FS A full rate Speech TCH

TDMA Time Division Multiple Access

TDP Transmitter Driver and PLL

TEI Terminal Equipment Identifier

TES Transmission Extension power Supply unit

TEU Transmission Extension Unit

TDU Timing Distribution Unit

TI Transaction Identifier

TMSI Temporary Mobile Subscriber Identity

TMU Timing/Transmission and Management Unit

TN Timeslot Number

TRAU Transcoder & Rate Adaptor Unit

TRB Transceiver Backplane

TRX Transceiver

TS Time Slot

Technical Specification

TSC Training Sequence Code

U

UI Unnumbered Information (frame)

V

VAD Voice Activity Detection

VLR Visitor Location Register

Z

ZCS Zero Current Switch

ZVS Zero Voltage Switch

HUAWEI


Part 2 BTS Maintenance Terminal System


BTS Maintenance Terminal SystemTable of Contents

i

Table of Contents

Chapter 1 Overview....................................................................................................................... 1-1 1.1 Brief Introduction to BTS Terminal Maintenance............................................................... 1-1

1.1.1 BTS Logic Objects .................................................................................................. 1-1 1.1.2 Status of BTS Logic Objects ................................................................................... 1-1

1.2 Brief Introduction to BTS Terminal Maintenance Operations ............................................ 1-2 1.2.1 User Login ............................................................................................................... 1-2 1.2.2 Interface Operation ................................................................................................. 1-3

Chapter 2 Site Maintenance ......................................................................................................... 2-1 2.1 Overview ............................................................................................................................ 2-1 2.2 Site Administrationship ...................................................................................................... 2-1 2.3 Start Site Operation ........................................................................................................... 2-3 2.4 View Resource................................................................................................................... 2-4 2.5 Force Load SW.................................................................................................................. 2-5 2.6 SW Activate ....................................................................................................................... 2-6 2.7 Site Hierarchical Reset ...................................................................................................... 2-8 2.8 Site Test............................................................................................................................. 2-9 2.9 Site Environment Monitoring............................................................................................ 2-10

Chapter 3 Cell Maintenance ......................................................................................................... 3-1 3.1 Overview ............................................................................................................................ 3-1 3.2 Cell Attributes Management .............................................................................................. 3-1 3.3 Cell OpStart ....................................................................................................................... 3-5 3.4 Change Cell Administrative State ...................................................................................... 3-5 3.5 Cell Performance Test ....................................................................................................... 3-6

Chapter 4 BT Maintenance ........................................................................................................... 4-1 4.1 Overview ............................................................................................................................ 4-1 4.2 OpStart BT ......................................................................................................................... 4-1 4.3 Change BT Administrative State........................................................................................ 4-2 4.4 BT Reinitialization .............................................................................................................. 4-3 4.5 BT Test .............................................................................................................................. 4-4

Chapter 5 Channel Maintenance.................................................................................................. 5-1 5.1 Overview ............................................................................................................................ 5-1 5.2 Channel Attributes Management ....................................................................................... 5-1 5.3 OpStart Channel ................................................................................................................ 5-3 5.4 Change Channel Administrative State............................................................................... 5-3 5.5 Loop Test ........................................................................................................................... 5-4


BTS Maintenance Terminal SystemTable of Contents

ii

Chapter 6 RC Maintenance........................................................................................................... 6-1 6.1 Overview ............................................................................................................................ 6-1 6.2 RC Attributes Management ............................................................................................... 6-1 6.3 OpStart RC ........................................................................................................................ 6-2 6.4 Change RC Administrative State ....................................................................................... 6-3 6.5 RC Reinitialization.............................................................................................................. 6-4

Chapter 7 Board Maintenance...................................................................................................... 7-1 7.1 Overview ............................................................................................................................ 7-1

7.1.1 Board Maintenance Function .................................................................................. 7-1 7.1.2 Board Maintenance Operations .............................................................................. 7-2

7.2 Board Reset ....................................................................................................................... 7-4 7.3 OpStart Board.................................................................................................................... 7-5 7.4 Board Self-test ................................................................................................................... 7-5 7.5 Change Board Administrative State................................................................................... 7-6 7.6 Board Information .............................................................................................................. 7-7 7.7 Loop Test ........................................................................................................................... 7-7 7.8 Board Alarm....................................................................................................................... 7-8 7.9 MCK Clock Operation ........................................................................................................ 7-9 7.10 Set MDC Parameters..................................................................................................... 7-10 7.11 CDU Operation .............................................................................................................. 7-11


BTS Maintenance Terminal SystemChapter 1 Overview

1-1

Chapter 1 Overview

1.1 Brief Introduction to BTS Terminal Maintenance

In BTS terminal maintenance, the PC (desktop or laptop, but usually the latter) that is installed with BTS terminal maintenance software is connected by serial communication cables to the TMU, the operation and maintenance unit of the BTS (which bears a 9-pin serial communication cable port and a network port).

BTS terminal maintenance is carried out according to BTS logic objects.

The logic objects of a BTS are introduced below.

1.1.1 BTS Logic Objects

In BTS terminal maintenance, the logic objects include: Site, Cell, BT (Baseband Transceiver), CH (Channel), RC (Radio Carrier) and Board, as shown in Figure 1-1 below:

Site

Cell-0 Cell-1

BT-0 BT-1 BT-n RC-0 RC-n

CH-0 CH-1CH-0 CH-7

… …

…

…

Cell-m

Figure 1-1 Logic objects of a BTS

1.1.2 Status of BTS Logic Objects

I. Management status

The management status of a BTS logic object is set by BTS system administrator. It indicates whether a logic object is available or not.

The management status of a BTS logic object includes:



1-2

Locked: Transceiving with the radio interface and/or the terrestrial baseband disabled.

Unlocked: Transceiving with the radio interface and/or the terrestrial baseband enabled.

ShutDown: The ongoing service provided involving this logic object will be maintained till release, but no new users are allowed access to this object.

Note:

A cell does not have the management status of ShutDown. The management status of a site determines whether a particular operator needs to obtain site administrationship before he is able to set BTS parameters.

II. Operational status

The operational status of a BTS logic object indicates whether the object is in normal operation.

The operation status of a BTS object includes:

Enabled Disabled

1.2 Brief Introduction to BTS Terminal Maintenance Operations

In BTS terminal maintenance, maintenance operations are carried out on a single local PC. In this section, detailed description of operations carried out through the BTS terminal maintenance console is provided.

1.2.1 User Login

I. Function

To log in as a user and activate the BTS terminal maintenance console.

II. Login

Click on the fifth button in the toolbar, or select [User/User Login] in the menu, and a user login dialogue box will pop up. Input the user name and password in this dialogue box, and click <OK>, as shown in Figure 1-2.



1-3

If the login succeeds, this dialogue box closes automatically, and the maintenance personnel are able to perform operations, while if the login fails, causes are displayed.

Figure 1-2 User login

1.2.2 Interface Operation

The interface for the BTS terminal maintenance console is divided into several parts such as menu, tool bar, BTS logic object, object function, alarm window, status bar, etc., as shown in Figure 1-3.

Buttons in the toolbar are shortcuts for some commands. The function of this button will be provided in the status bar when the cursor is stopped at this button.



1-4

Figure 1-3 BTS terminal maintenance console

The bottom part of this interface (blue in Figure 1-3) is where BTS alarm information is to be displayed.

Click on any piece of the alarm information displayed, and the detailed explanation of the alarm will be provided in the popped up window (as shown in Figure 1-5).

Right click to activate the floating menu, as shown in Figure 1-4. Select from menu items to set, save, clear the alarm information, or browse along the list of alarm information.



1-5

Figure 1-4 BTS terminal maintenance console alarm display

Figure 1-5 Operation on alarm information



1-6

Figure 1-6 Detailed explanation of alarm information


BTS Maintenance Terminal SystemChapter 2 Site Maintenance

2-1

Chapter 2 Site Maintenance

2.1 Overview

There may be one or more cells at a site. The maintenance of the site involves the maintenance over the entire BTS.

Figure 2-1 shows the interface [Site Maintenance Terminal System] in the BTS maintenance console.

In the following sections, site maintenance functions are explained in detail.

Figure 2-1 The interface [Site Maintenance Terminal System]

2.2 Site Administrationship

I. Function

Site administrationship is the authority to set the various BTS parameters. BTS parameters can be set either at the BSC or the local BTS maintenance terminal. However, BTS parameter setting cannot be performed at the same time at both the



2-2

BSC and the local BTS terminal. Therefore, site administrationship will be granted to one side at a time.

When a site is installed and begins to run, BSC has the site administrationship by default. Therefore the maintenance personnel need to obtain site administrationship before performing any operation at a BTS terminal.

When the operation is over, please release the site administrationship.

II. Access

Activate BTS terminal maintenance console, and select [Site/Site Administrationship]. Click <Obtain> or <Release> in the popped up dialogue box to obtain or release site administrationship, and the operational result will be displayed in this box, as shown in Figure 2-2.

Figure 2-2 Site administrationship (obtain administrationship)

When the operation is over, the administrationship must be released. Otherwise, maintenance personnel will be blocked from performing remote maintenance.

The interface of releasing the administrationship is shown in Figure 2-3.



2-3

Figure 2-3 Release the administrationship

2.3 Start Site Operation

I. Function

To put the site data set in BTS operation and maintenance unit into effect and start the service of the site.

II. Access

Activate BTS terminal maintenance console, and select [Site/Site OpStart]. Click <OK> in the popped up message box [Start Site Operation]. The result of the operation will be displayed in the status bar, as shown in Figure 2-4.

Figure 2-4 Start Site Operation



2-4

2.4 View Resource

I. Function

The maintenance personnel can view the status of resource utilization in the terminal maintenance system of the BTS, specifically, the utilization ratio of the CPU and the RAM of TMU and TRX.

II. Access

Activate BTS terminal maintenance console, and select [Site/View Resource], and the resource utilization status of the TRX and the TMU of the site will be displayed in the popped-up window.

Select in [Resource Type] to determine the type of resource whose utilization status is to be viewed. As is shown in Figure 2-5, Figure 2-6.

Figure 2-5 View the status of resource



2-5

Figure 2-6 View CPU status

2.5 Force Load SW

I. Function

The BTS software can be upgraded from both the local and the remote terminal. Software upgrading for TMU, TRX and PBU can therefore be easily achieved.

II. Access

Activate BTS terminal maintenance console, select [Site/Forced Load SW], and the dialogue box [SW Download] will pop up.

Select in this dialogue box the name of the software and the type of the files to be loaded, and click <Begin>.

The progress of software loading will be displayed at the maintenance console, as shown in Figure 2-7.

When it is promoted that ‘Software loading successful’, click <Close> to complete the forced software loading from the maintenance console to the BTS.



2-6

Figure 2-7 The Dialogue Box [SW Download]

III. Interface description

For the description of the interface in Figure 2-7, please see Table 2-1 below.

Table 2-1 [SW Download]

Field Description Value range Recommended value

File Name The name of the file saved on the maintenance console that is to be loaded

Send Window Size

The data for software loading is transferred with the window size as one unit

1~49 49

Version Version number of the software to be loaded

Must be the same as the version number specified in the file to be loaded, otherwise the loading will fail.

File ID For which type of board the software upgrading is to be carried out Must be the same as the type of

the file to be loaded.

2.6 SW Activate

I. Function

After the forced BTS software loading, activate the software. The software upgrading task is not yet completed before the loaded software is activated.



2-7

II. Access

Activate BTS terminal maintenance console, select [Site/SW Activate], and the interface [SW Activate] (as shown in Figure 2-8 and Figure 2-9) will pop up. Input the version of the software to be activated, select the corresponding board number and file ID, and click <OK>. If the activation is successful, the prompt ‘SW activation request is confirmed’ will be displayed.

Figure 2-8 Activating the TMU board software

Figure 2-9 Activating the TRX board software



2-8


For the description of the software activation interface, see Table 2-2.

Table 2-2 The Interface [SW Activate]

Field Meaning Value range Recommended value

Version Version number of the loaded software

Must be the same as the version number of the software to be loaded, otherwise the activation will fail.

Board No. Number of the specified board that is to be activated

Format: 0, 1, 0-X, etc. (X being the number of the TRXs configured)

File ID Type of board for which the software upgrading is to be carried out

2.7 Site Hierarchical Reset

I. Function

Site resetting is performed as a remedy when a site is abnormal.

Resetting a site will stop the services of the cells for several minutes under this site. Therefore, care should be taken with this function.

II. Access

Enter the maintenance console of the BTS, select [Site/Site Reset Hierarchically]. The interface [Site Hierarchical Reset] will pop up. Select the level of the resetting in this interface, and click <OK>, as shown in Figure 2-10.



2-9

Figure 2-10 The 'Site Hierarchical Reset' interface


For description of the interface [Site Hierarchical Reset], see Table 2-3.

Table 2-3 Site resetting levels

Reset level Meaning

First Level Reset Currently not supported by the BTSs.

Please see the definition of this level of resetting on the interface.

Second Level Reset Currently not supported by the BTSs.

Please see the definition of this level of resetting on the interface.

Third Level Reset Please see the definition of this level of resetting on the interface.

In this level of resetting, the base station applies to BSC side for the re-sending of data configuration.

Fourth Level Reset Please see the definition of this level of resetting on the interface. In this level of resetting, base station TMU hardware resetting is performed, and the base station re-applies for BSC data configuration.

2.8 Site Test

I. Function

To test the functional boards configured for the site, and return the test results.



2-10

II. Access

Activate BTS terminal maintenance console, and select [Site/Site Test]. The interface [Site Test] will pop up. Click <Begin>, and the test results will be displayed in this interface, as shown in Figure 2-11.

Figure 2-11 Site test results

2.9 Site Environment Monitoring

I. Function

To implement operations on the environment monitoring box such as resetting the environment monitoring box, clearing the burglary alarm, setting the upper and lower limits for humidity and temperature alarms, relay operation and disable the EAC alarm.

Caution:

In this system, burglary alarm, fire alarm and smoke alarm are all reported as burglary alarm. Therefore, the occurrence of any of them will trigger the burglary alarm.

II. Access

Activate BTS terminal maintenance console, and select [Site/Environment Monitoring Setting]. The interface [Environment Monitoring Setting] will pop up, as shown in Figure 2-12.



2-11

Figure 2-12 Environment monitoring setup

Resetting of the environment monitoring instrument is performed when the equipment is in abnormal service. Select ‘Reset’ in [Select Operation Type]. Click <OK>, then the resetting can be performed and the operational result will be displayed, as shown in Figure 2-13.

Figure 2-13 Resetting operation

When the burglary alarm is confirmed or cleared, please clear the burglary alarm record. Select ‘Clear Burglary alarm’ in [Select Operation Type]. Click <OK>, and



2-12

the burglary alarm record will be cleared, and the operational result will be displayed in the status bar, as shown in Figure 2-14.

Figure 2-14 Clear burglary alarm

Conditions for the generation of environment alarms can be determined by the upper and lower limits for temperature and humidity. Select ‘Set Temperature and Humidity’ in [Select Operation Type] and set the upper and lower limits for alarm generation in [Temperature and Humidity]. Click <OK>. The operational result is displayed in the status bar, as shown in Figure 2-15.

Figure 2-15 Set upper and lower limits for temperature and humidity



2-13

With the implementation of relay operation, maintenance can startup and close some relevant equipment. Select ‘Relay Operation’ in [Select Operation Type], and set the starting and closing of the relevant relays in ‘Relay Operation’. Click <OK> and the operational result will be displayed, as shown in Figure 2-16.

Figure 2-16 Relay operation

Select ‘Disable the EAC Alarm’, and the alarm report will be shut down for 10 minutes. This is performed by the maintenance personnel in equipment maintenance to prevent the mis-generation of false alarms caused by their operations. Select ‘Disable the EAC Alarm’ in [Select Operation Type], and click <OK>. The operational result will be displayed, as shown in Figure 2-17.

Figure 2-17 Disable the EAC alarm


BTS Maintenance Terminal SystemChapter 3 Cell Maintenance

3-1

Chapter 3 Cell Maintenance

3.1 Overview

A cell corresponds to an inseparable wireless service area and may include one or more baseband transceivers and radio carrier units. A cell should have a BCCH to broadcast cell information.

When it is necessary to carry out maintenance over a cell or over all the baseband transceivers and radio carriers in a cell, perform cell maintenance to achieve this, as shown in Figure 3-1.

Figure 3-1 Cell maintenance

3.2 Cell Attributes Management

I. Function

On-the-spot site maintenance and debugging operation often involve the setting of various attribute parameters at a BTS terminal.



3-2

Cell attributes management involves the setting of cell attributes. With cell attributes management, cell attributes can also be obtained.

The setting of the other attribute parameters will be described later in this module.

II. Access

Activate BTS maintenance console, and select [Cell/Cell Attributes Management]. The interface [Cell Attributes Management] will pop up. Input the proper values in this interface, and click <Set>, as shown in Figure 3-2, Figure 3-3, and Figure 3-4. Click <Refresh> to obtain the cell attributes.

Figure 3-2 Cell attributes management (a)



3-3

Figure 3-3 Cell attributes management (b)

Figure 3-4 Cell attributes management (c)


For the description of the above interfaces, see Table 3-1.



3-4

Table 3-1 Cell attributes


Interference level boundary

There are six interference levels, therefore 6 parameters need to be configured. The BTS calculates the interference level on the channel according to the MR (measurement report) from the mobile station. After the calculation is compared with the six levels, the interference level of the channel can be obtained.

-115~85.

The six parameters should be arranged in ascending sequence.

Interference average parameter

The BTS calculates the level of interference according to the reports received from the mobile station. This parameter determines the number of reports a BTS receives before it makes such a calculation

0 ~255 15

Connection failure threshold

BTS makes comparisons the report from the mobile station and the error rate with the level, and determine if the connection fails.

0 ~16 14

T200 The timer interval for waiting for response when there is no response after a message is transferred.

Max time advanced

The farthermost timing advance in the coverage area of a cell. 0 ~63 63

Overload period

A span in time that serves as an interval for the BTS to calculate the occupation rate of the channel.

0 ~255

CCCH load threshold

Ratio between the number of successful random accesses in a time unit and the number of collisions during this time unit.

0 ~100% 80%

CCCH load indication period

The interval a which the BTS reports to the network side if CCCH is overloaded. 15s

RACH busy threshold The level of the random access threshold. -110 ~145 dBm

The range is decided by the operator

RACH load averaging slots

The random access channel load average timeslots on RACH.

Cell air timer The timing period of the timer.

NY1 Maximum number of physical information retransmissions. (Relevant to handover). Usually 6 and 4

BCCH ARFCN There are 124 and 374 frequencies respectively in the M900 system and M1800 system. This field means the number of the frequency of BCCH.



3-5


BSIC BTS color code. BSIC equals the sum of the network color code and the cell color code.

Starting frame No.

No. of the frame that the setting in this interface to be valid for. If the settings are desired to take effect right away, this parameter should be 65535.

0 ~ 42432, 65535 65535

3.3 Cell OpStart

I. Function

To put the site data set at the BTS operation and maintenance terminal into effect and put the cell into service.

II. Access

Activate BTS maintenance console, and select [Cell/Cell OpStart]. The interface [Start Cell Operation] will pop up. Click <OK>, and the operational result will be displayed in the status bar, as shown in Figure 3-5.

Figure 3-5 Cell OpStart

3.4 Change Cell Administrative State

I. Function

In some cases the cell administrative state needs to be changed. This can be achieved through the BTS terminal.



3-6

The cell administrative state can be set to ‘Locked’ or ‘Unlocked’. However, please note that when the administrative state is successfully set to ‘Locked’, all the channels in the cell are in ‘Out of Service’ state, which means the cell is not in service and the MSs in this service area can not access the network or make/answer any call. Therefore, care should be taken with this function.

II. Access

Activate BTS maintenance console, and select [Cell/Change Administrative State]. The interface [Change Cell Administrative State] will pop up. Select the administrative state to be changed into and click <OK>, as shown in Figure 3-6.

Figure 3-6 Change cell administrative state

3.5 Cell Performance Test

I. Function

To check all basebands and RCs in the cell to see if they are working normally.

II. Access

Activate BTS maintenance console, and select [Cell/Cell Test]. Click <Begin> in the popped up interface, and the test result will be displayed in this interface, as shown in Figure 3-7.



3-7

Figure 3-7 Cell performance test


BTS Maintenance Terminal SystemChapter 4 BT Maintenance

4-1

Chapter 4 BT Maintenance

4.1 Overview

Baseband Transceiver (BT) is a function entity involved in baseband processing. It corresponds to the 8 timeslots at the radio interface. The BTS terminal maintenance over the BT logic objects is shown in Figure 4-1.

Figure 4-1 BT maintenance

4.2 OpStart BT

I. Function

To enable the data set at the BT and put the BT into service through BTS terminal maintenance.



4-2

II. Access

Activate BTS maintenance console, select [BT/BT OpStart] and click <OK> on the pop-up interface, and the operational result will be displayed in this interface, as shown in Figure 4-2.

Figure 4-2 BT OpStart

4.3 Change BT Administrative State

I. Function

The administrative state of BT can be changed according to operations at the maintenance console. However, please note that changing the BT administrative state into ’Locked’ or ‘ShutDown’ will affect service provision. Therefore, care should be taken with this function.

II. Access

Activate BTS maintenance console, and select [BT/Change BT Administrative State]. Select the BT whose administrative state needs to be changed in the pop-up interface and select the administrative state to be changed into, then click <OK>. The operational result will be displayed in the right half of this interface, as shown in Figure 4-3.



4-3

Figure 4-3 Change BT administrative state

4.4 BT Reinitialization

I. Function

To reset the hardware of the BT. This will disconnect the users from the BT. Therefore, care should be taken with this function.

II. Access

Activate BTS maintenance console, select [BT/BT Reinitialization], and click <OK> in the pop-up interface, and the operational result will be displayed in the interface, as shown in Figure 4-4.

Figure 4-4 BT reinitialization



4-4

4.5 BT Test

I. Function

BT test includes:

BIU loop test TRX self-test

The BIU loop test involves the testing of physical links between the Abis signaling channel of the BSC and the baseband part of the TRX. On receiving the command, BT board performs the test, and reports the test result. The operation personnel can judge if the Abis link of the current BT board is normal according to the reported results.

In the TRX self-test, self-test is performed over the TRX and the test results are returned.

II. Access

Activate BTS maintenance console, select [BT/BT Test]. Select test items in the pop-up interface (e.g., BIU loop test /TRX self-test), set ‘Test time’ and click <Begin> to start the test. When the test is over, the result will be displayed in this interface, as shown in Figure 4-5 and Figure 4-6.

Figure 4-5 BIU loop test



4-5

Figure 4-6 TRX self-test


BTS Maintenance Terminal SystemChapter 5 Channel Maintenance

5-1

Chapter 5 Channel Maintenance

5.1 Overview

A channel is a transceiving entity of a timeslot at the radio interface.

A physical channel is determined by its corresponding timeslot and frequency parameters, and may correspond to several logic channels due to different combinations of channels.

Maintenance over the channel is shown in Figure 5-1.

Figure 5-1 Channel maintenance

5.2 Channel Attributes Management

I. Function

To set the attributes of BTS channel on the BTS site. With channel attributes management, channel attributes can be obtained.



5-2

II. Access

Activate BTS maintenance console, and select [Channel/Channel Attributes Management]. Input appropriate parameters, and click <Set>. The result of the setting will be displayed on the status bar in the window, as shown in Figure 5-2. Click <Refresh> to obtain the channel attributes.

Figure 5-2 Channel attributes management


For the description of the above interface, see Table 5-1.

Note:

The configuration of channel parameters must be the same as that at the BSC side, otherwise the system will not be able to operate normally.

Table 5-1 Description of the interface [Channel Attributes Management]

Channel attribute Description Value range Recommende

d value

Channel combination

Combination of logic channels carried by the physical channel

See the pulldown list

TSC selection The demodulation part of BT is used to calculate channel features for correct decoding of valid information.

0 ~ 7



5-3

Channel attribute Description Value range Recommende

d value

Starting frame No.

No. of the frame that the setting in this interface to be valid for. If the settings are desired to take effect right away, this parameter should be 65535.

0 ~ 42432, 65535 65535

5.3 OpStart Channel

I. Function

To validate the data setting of the channel.

II. Access

Activate BTS maintenance console, and select [Channel/OpStart Channel]. Click <OK> in the pop-up interface, and the operational result will be displayed in the status bar, as shown in Figure 5-3.

Figure 5-3 OpStart channel

5.4 Change Channel Administrative State

I. Function

The administrative state of the channels can be changed by operations at the maintenance console.

However, please note that changing the BT administrative state into 'LOCKED' will affect service provision. Therefore, care should be taken with this function.



5-4

II. Access

Activate BTS maintenance console, and select [Channel/Change Administrative State]. Select the channel whose administrative state is to be changed, and click <OK>. The operational result will be displayed in the sub-window on the right of this interface, as shown in Figure 5-4 and Figure 5-5.

Figure 5-4 Channel in 'Locked' state

Figure 5-5 Channel in 'Unlocked' state

5.5 Loop Test

I. Function

Channel loop test involves the testing of BT parameters such as channel error rate and transmitted power for the purpose of getting a better idea of the quality of the channel.



5-5

Currently, BTS30 supports:

TRX RF self-loop test BIU loop test

In the TRX RF self-loop test, mainly the performance of the RF unit is tested. After the TMU issues a test command, the TRX transfers data to the RF unit on a traffic channel, and the data loops back from the RF unit so that the TRX can receive the traffic channel data sent by itself. After comparing the received data with the copy of it that was sent earlier, the TRX report the error rate and thus determines the link quality of the current RF unit.

The BIU loop test mainly involves the testing of the connection state between the TMU and the TRX. The data sent from the TRX loops back from the TMU. After comparison, the error rate will be calculated so as to judge if the connection between TMU and TRX is normal.

II. Access

Activate BTS maintenance console, and select [Channel/Loop Test]. Select appropriate test items in the pop-up interface, set the test time and the power level for the TRX RF self-test. Click <OK> to start the test. For illustration of the TRX FR self-loop test and the BIU loop test, see Figure 5-6 and Figure 5-7 below.

Figure 5-6 Result of BIU loop test



5-6

Figure 5-7 Result of TRX RF self-loop test


BTS Maintenance Terminal SystemChapter 6 RC Maintenance

6-1

Chapter 6 RC Maintenance

6.1 Overview

The radio carrier (RC) is a transceiving entity corresponding to the eight timeslots at the radio interface. Operation and maintenance to the RC will be introduced in detail in the following sections.

Figure 6-1 RC maintenance

6.2 RC Attributes Management

I. Function

RC attributes management involves the setting of RC attributes during BTS site maintenance and commissioning.

With this function, the RC attributes can be obtained.



6-2

II. Access

Activate BTS maintenance console, and select [RC/RC Attributes Management]. Input RC attributes in the pop-up interface, and click <Set>.The operational result will be displayed in the status bar in the window, as shown in Figure 6-2. Click <Refresh> to obtain the RC attributes.

Figure 6-2 RC attributes management



Table 6-1 Description of the interface [RC Attributes Administration]

RC attribute Meaning

RF Max power reduction

The maximum value of power reduction. When the power reduction value exceeds this value, it can not be reduced any further.

ARFCN In the M900/M1800 systems, there are 124 (numbered 0 ~ 123) and 374 (numbered 512 ~ 885) frequencies respectively. ARFCN refers to the frequency number of this RC. The value of the 900MHz RCs ranges 0 ~ 124, and that of 1800MHz RCs 512 ~ 885.

6.3 OpStart RC

I. Function

To put the set RC data (RC attributes and RC extended attributes) into effect.



6-3

II. Access

Activate BTS maintenance console, and select [RC/RC OpStart]. Click <OK>, and the operational result will be displayed in the pop-up interface [Start RC Operation], as shown in Figure 6-3.

Figure 6-3 Opstart RC

6.4 Change RC Administrative State

I. Function

The administrative state of an RC can be changed by operations at the maintenance console.

However, please note that changing the RC administrative state into 'LOCKED' will affect service provision. Therefore, care should be taken with this function.

II. Access

Activate BTS maintenance console, and select [RC/Change Administrative State]. In the pop-up interface, select the BT whose administrative state is to be changed and the target administrative state, and click <OK>. The operational result will be displayed in the sub-window on the right of this interface, as shown in Figure 6-4 and Figure 6-5.



6-4

Figure 6-4 RC in the 'LOCKED' state

Figure 6-5 RC in 'UNLOCKED' state

6.5 RC Reinitialization

I. Function

This is the reconfiguration of TRX data and the resetting of TRX. RC resetting will lead to the disconnection of users of the corresponding BT. Therefore, care should be taken with this function.

II. Access

Activate BTS maintenance console, and select [RC/RC Reinitialization]. Click <OK> in the pop-up window, and the operational result will be shown in this interface, as shown in Figure 6-6.



6-5

Figure 6-6 RC reinitialization


BTS Maintenance Terminal SystemChapter 7 Board Maintenance

7-1

Chapter 7 Board Maintenance

7.1 Overview

7.1.1 Board Maintenance Function

Visual and direct maintenance is achieved with the BTS terminal maintenance console. Double click on [Board/BoardAdm] in the maintenance console, and the interface for board maintenance will pop up, as shown in Figure 7-1.

Hardware configurations (as in the Slot Description table) set by the BSC for a site are displayed in this interface, and the No., name and status of the boards can be obtained from the display.

Operations can be performed in this interface. Select and right click on the icon of the board to be operated on, and execute the menu command you desire from the floating menu that pops up. Note that different maintenance commands apply to different boards.

Figure 7-1 Board operation



7-2

7.1.2 Board Maintenance Operations

There are unified operation procedures for board maintenance: 1) Activate board maintenance interface. 2) Right click on the icon of the board to be operated on. 3) Select the corresponding function in the pop-up menu.

The TRX maintenance menu is as shown in Figure 7-2. The TMU maintenance menu is as shown in Figure 7-3. The CDU maintenance menu is as shown in Figure 7-4. The PMB maintenance menu is as shown in Figure 7-5.

Figure 7-2 TRX maintenance menu



7-3

Figure 7-3 TMU maintenance menu

Figure 7-4 CDU maintenance menu



7-4

Figure 7-5 PMB maintenance menu

7.2 Board Reset

I. Function

To reset boards, i.e., to reinitialize the corresponding boards.

Please note that the resetting of a board may affect the sessions of the subscribers. Therefore, care should be taken with this function.

II. Access

Select [Reset] in the board operation menu, and the result will be displayed in the pop-up interface, as shown in Figure 7-6.

Figure 7-6 Board reset



7-5

7.3 OpStart Board

I. Function

To put the data configurations of the objects into effect.

II. Access

Select [OpStart] in the board operation menu, and the operational results will be displayed in the pop-up interface, as shown in Figure 7-7.

Figure 7-7 OpStart Board

7.4 Board Self-test

I. Function

The board tests by itself if the board software is running normally.

II. Access

Select [Test] in the operation menu, and the test results will be displayed in the pop-up interface, as shown in Figure 7-8.

Figure 7-8 Board self-test



7-6

7.5 Change Board Administrative State

I. Function

The meaning of the operations on the TRX board administrative state is the same as on the BT administrative state in the logic object operations. In board operations, operations on the administrative state of the channel of the BT corresponding to the TRX can also be performed. And it also means the same as with the operations on the administrative state of channel objects.

II. Access

To operate on the administrative state of the logic object: Right click on the icon of the board, and select [Administrative State/Locked] or [Administrative State/ Unlocked].

To operate on a certain channel of the logic object: Right click on the icon of the board, and select [Administrative State/Block Channel], and select the channel to be operated on.

See Figure 7-9.

Figure 7-9 Change board administrative state



7-7

7.6 Board Information

I. Function

To query the software version and the number of alarms generated during board maintenance.

II. Access

Right click on the icon of the board, and select [Board Information]. The result of the query will be displayed in the pop-up interface, as shown in Figure 7-10.

Figure 7-10 Board information

7.7 Loop Test

I. Function

To test if the link between the board and the TMU is normal.

The initialization and maintenance of the boards in BTS are accomplished with the TMU, the BTS operation and maintenance unit, therefore links between the boards and the TMU are very important.

II. Access

Right click on the icon of the board, and select [Loop Test]. The interface [Loop Test] will pop up, as shown in Figure 7-11.



7-8

Figure 7-11 Board loop test


For the description of the interface [Loop Test], see Table 7-1.

Table 7-1 Description of the interface [Loop Test]

Field Description Value range

Data Length Valid single-frame data length of the loop test command issued by the TMU to the board. 1 ~ 220

Initial Data Valid initial data of the loop test command issued by the TMU to the board. 0 ~ 255

Data Step Length

Data increment length of the loop test command issued by the TMU to the board. 0 ~ 255

7.8 Board Alarm

I. Function

BTS reports on the abnormality that occurs during BTS operation it to the BSC side in the form of an alarm.

The maintenance personnel can observe the real-time alarms through the alarm message window at the maintenance terminal of the BTS to facilitate the maintenance operations. They can also obtain information on alarms by querying them.



7-9

II. Access

Right click on the icon of the board, and select [Board Alarm]. The interface [Board Alarm Information] will pop up. On the left of this window is a visual diagram for board alarms, where each grid stands for an alarm. If the grid is green, the corresponding board is normal, while if red, the board is faulty. In this case, click the grid that is red, and a detailed explanation of the alarm will be displayed in the sub-window on the right of the interface, as shown in Figure 7-12.

Figure 7-12 Board alarm information

7.9 MCK Clock Operation

I. Function

The BTS clock can work both in the mode of internal clock (free-run mode), external clock (phase-locked mode) and external synchronization clock. The selection of the operational mode of the BTS clock can be done through TMU maintenance.

II. Access

In the TMU maintenance menu, select [Set CLK Hardware Parameters], then select the clock mode and input the parameters in the pop-up interface. Then click <OK>, and the operational result will be displayed in the window, as shown in Figure 7-13.



7-10

Figure 7-13 Select the MCK clock mode



Table 7-2 MCK clock mode selection


Clock mode

Internal clock: the BTS clock unit works in free-run mode and can not ensure the synchronization with the network clock.

External clock: the BTS clock unit works in phase-locked mode, and is in synchronization with the network clock.

Set DAC This parameter is an adjustment of the crystal oscillation voltage. 0000~4095 (decimal)

7.10 Set MDC Parameters

I. Function

To set the CDU parameters of the BTS antenna and feeder part in board maintenance.

II. Access

In the CDU maintenance menu (refer to section 7.1), select [Set MDC Parameters], input appropriate parameters in the pop-up interface, click <OK>, and the operational result will be displayed in the status bar, as shown in Figure 7-14.



7-11

Figure 7-14 Set MDC parameters



Table 7-3 Description of the interface [Set MDC Parameters]


Device type CDU( combiner and splitter); HYCM ( combiner); SPL (splitter)

Subroute No. Tributary No. of uplink signal 0: main tower top amplifier; 1: diversity tower top amplifier

Attenuation value Power attenuation for the uplink signal 0 ~ 15 dB

7.11 CDU Operation

I. Function

To provide the control function for switching on/off the tower top amplifier in CDU maintenance.

II. Access

In the CDU maintenance menu, select [CDU Operation], select the operation to be performed in the pop-up interface, click <OK>, and the operational result will be displayed in the status bar, as shown in Figure 7-15.



7-12

Figure 7-15 CDU operation

HUAWEI


Part 3 BTS Maintenance


BTS MaintenanceTable of Contents

i

Table of Contents

Chapter 1 Routine Maintenance Instructions............................................................................. 1-1 1.1 Routine Maintenance Overview......................................................................................... 1-1

1.1.1 Purpose of Routine Maintenance............................................................................ 1-1 1.1.2 Routine Maintenance Classification........................................................................ 1-1 1.1.3 BTS Routine Maintenance Record & Instructions................................................... 1-2

1.2 Weekly Maintenance Instructions ...................................................................................... 1-8 1.3 Monthly Maintenance Instructions ..................................................................................... 1-9 1.4 Quarterly Maintenance Instructions................................................................................... 1-9 1.5 Yearly Maintenance Instructions...................................................................................... 1-10 1.6 Return Loss, VSWR and Reflection Coefficient .............................................................. 1-11

Chapter 2 Fault Analysis and Location....................................................................................... 2-1 2.1 Communication Fault ......................................................................................................... 2-1

2.1.1 Introduction to Mobile Station's Search for the Network ......................................... 2-1 2.1.2 Call Failure .............................................................................................................. 2-2 2.1.3 No Voice Heard after the Call is Connected ........................................................... 2-5 2.1.4 Unidirectional Talk................................................................................................... 2-6 2.1.5 Poor Voice Quality .................................................................................................. 2-7 2.1.6 Conversation Interruption........................................................................................ 2-8 2.1.7 Cross Talk ............................................................................................................... 2-9 2.1.8 Mobile Station Frequently Disconnected from the Network.................................... 2-9 2.1.9 Immediate Assignment Rejection.......................................................................... 2-10

2.2 Network Fault................................................................................................................... 2-11 2.2.1 Mobile Station Fails to Find a Network ................................................................. 2-11 2.2.2 Mobile Station Fails to Access the Network.......................................................... 2-12 2.2.3 MS Frequent Location Updating ........................................................................... 2-15

2.3 Loading Fault ................................................................................................................... 2-16 2.3.1 Software Loading Failure ...................................................................................... 2-16 2.3.2 Base Station Initialization Failure.......................................................................... 2-18

2.4 Signaling Fault ................................................................................................................. 2-20 2.4.1 OML Link Blocked ................................................................................................. 2-20 2.4.2 RSL Link Blocked.................................................................................................. 2-21

2.5 Antenna and Feeder System Fault .................................................................................. 2-22 2.6 Optical Channel Fault ...................................................................................................... 2-23 2.7 Board Fault ...................................................................................................................... 2-24

2.7.1 CDU....................................................................................................................... 2-24 2.7.2 EDU....................................................................................................................... 2-26 2.7.3 PBU ....................................................................................................................... 2-29


BTS MaintenanceTable of Contents

ii

2.7.4 PMU ...................................................................................................................... 2-31 2.7.5 PSU ....................................................................................................................... 2-34 2.7.6 TES ....................................................................................................................... 2-36 2.7.7 TEU ....................................................................................................................... 2-37 2.7.8 TMU....................................................................................................................... 2-39 2.7.9 TRX ....................................................................................................................... 2-42


BTS MaintenanceChapter 1 Routine Maintenance Instructions

1-1

Chapter 1 Routine Maintenance Instructions

1.1 Routine Maintenance Overview

1.1.1 Purpose of Routine Maintenance

Reliable running of the BTS depends on effective routine maintenance. The aim of such maintenance is to detect and solve problems in time.

This chapter describes the contents of routine maintenance and the correct operation procedures, thus providing the basic methods and reference basis of routine maintenance for users in deciding local office maintenance solutions.

1.1.2 Routine Maintenance Classification

I. Classification by Implementing Methods

1) Conventional maintenance

To observe, test and analyze the equipment performance and operating conditions by means of normal maintenance.

2) Unconventional maintenance

To check whether the equipment performance has degraded by observing, testing and analyzing it in artificially-created special conditions.

For example, to avoid alarm system fault, the maintenance personnel can deliberately create some faults and check whether the alarm system can generate reports correctly.

II. Classification by Period Length

1) Unscheduled maintenance

Maintenance tasks incurred by equipment fault and network adjustment.

For example, the maintenance operations required at the time of user complaint, equipment damage and line fault are unscheduled. In addition, problems found and recorded in routine maintenance are also one of the triggering factors of unscheduled maintenance operations.

2) Daily routine maintenance



1-2

Maintenance operations conducted every day, which help the maintenance personnel keep track of equipment running conditions and solve problems in time.

When a problem is found in daily maintenance, please record in detail the exact physical position where it occurs and describe it in detail, so that maintenance operations can be conducted in time to avoid bigger trouble.

3) Periodical routine maintenance

Maintenance operations conducted regularly, which help the maintenance personnel keep track of the long-time performance of the equipment.

Periodical routine maintenance includes quarterly and yearly maintenance.

1.1.3 BTS Routine Maintenance Record & Instructions

BTS Weekly Maintenance Record

Please note down in this record the operations actually conducted in BTS weekly maintenance. For methods of conducting weekly maintenance operations, please refer to BTS Weekly Maintenance Instructions.

BTS Monthly Maintenance Record

Please note down in this record the operations actually conducted in BTS monthly maintenance. For methods of conducting monthly maintenance operations, please refer to BTS Monthly Maintenance Instructions.

BTS Quarterly Maintenance Record

Please note down in this record the operations actually conducted in BTS quarterly maintenance. For methods of conducting quarterly maintenance operations, please refer to BTS Quarterly Maintenance Instructions.

BTS Yearly Maintenance Record

Please note down in this record the operations actually conducted in BTS yearly maintenance. For methods of conducting yearly maintenance operations, please refer to BTS Yearly Maintenance Instructions.

BTS Unexpected Fault Handling Record

Please note down in this record the operations actually conducted in clearing the unexpected faults that come up in BTS routine maintenance.

This record serves as a basis for future reference in equipment maintenance. The maintenance personnel may modify the list of items in this record according to the actual conditions of the local office, and compile several sheets of records into a handbook on the clearing of unexpected faults.



1-3

I. BTS Unexpected Fault Handling Record

Site name Home BSC

Time when faults occur Time when faults get solved

Person on duty Faults handled by

Fault type:

Primary power supply

Baseband frame

Antenna and feeder system

Secondary power supply

TRX frame

Others

Sources of fault information

Subscriber complaints

Discovery in daily maintenance

Alarm system

Other sources

Fault description:

Handling methods and results:



1-4

II. BTS Weekly Maintenance Record

Site name:

Maintenance time: Maintenance personnel:

Maintenance item Maintenance status Remarks Maintenance personnel

Environment condition Normal Abnormal

Temperature condition Normal Abnormal

Humidity condition Normal Abnormal

Dust-proof condition Normal Abnormal

Indoor air-conditioner running state Normal Abnormal

Board running state Normal Abnormal

Fault description and handling

Problems remained

Checked by shift leader



1-5

III. BTS Monthly Maintenance Record

Site name:



Call test Normal Abnormal

Check working status of battery set Normal Abnormal

Check grounding, lightning arrester and power supply system

Normal Abnormal

Check running status of antenna and feeder Normal Abnormal

Check running status of secondary power supply Normal Abnormal


Problems remained




1-6

IV. BTS Quarterly Maintenance Record

Site name:



Check primary power supply Normal Abnormal

Check running conditions of fan Normal Abnormal

Road test Normal Abnormal

VSWR test Normal Abnormal

Check alarm collecting devices Normal Abnormal

Fault description and the handling

Problems remained




1-7

V. BTS Yearly Maintenance Record

Site name:



Check running state of channel Normal Abnormal

Cabinet cleanness Normal Abnormal

Check base station power output Normal Abnormal

Earth resistance test and grounding cable check Normal Abnormal

Check the waterproof status of antenna and feeder connectors and lightning-proof grounding cards

Normal Abnormal

Check the firmness of antenna and tower-top amplifier and the tilting angle of directional antenna

Normal Abnormal


Problems remained




1-8

1.2 Weekly Maintenance Instructions

Maintenance item Operation instructions Reference standard

Check the machine room for any environment alarm including power supply, fire and smoke alarms.

Everything should be normal. No alarm appears.

Environment condition Check the anti-theft net, doors and windows, and other facilities in the equipment room.

The facilities including anti-theft net, doors and windows ought to be intact.

Temperature condition Observe the thermometer indication in the equipment room.

Normal equipment room environmental temperature: 15 C~30 C.

Humidity condition Observe the hygrometer indication in the equipment room.

Normal equipment room environmental humidity: 40% ~ 65%.

Dust-proof condition Observe equipment housing, equipment interior, floor and desktop.

All items should be clean without any visible dust attaching. Then the dust-proof condition is good. If any item is not up to the standard, then the dust-proof condition is bad.

Indoor air conditioner running status Check whether it is normally running and whether the refrigeration function is good.

The indication of the thermometer is consistent with the temperature set and the refrigeration system works.

Board running status Observe whether indicators of all boards are normal.



1-9

1.3 Monthly Maintenance Instructions


Call Test

Use the testor mobile station to perform call test with another one cooperating beside the BSC, and observe whether calls are normal over all channels.

There should be no noises, interruptions or crosstalk.

Check the running status of battery sets

Check whether there is liquid leakage regarding the battery, or the connection is loose.

Check the grounding, lightning arrester and power supply systems

Check whether the grounding system and lightning protection system are working normally, whether the connection is reliable, whether the power supply system is working normally and whether there is any scorch for the lightening arrester.

Make sure the signal lightning arrester, power supply lightning arrester, antenna and feeder lightning arrester are in good condition.

Check the working status of antenna and feeder system

Check whether there is standing wave alarm, whether there is deviation of antenna support, and whether the waterproofness of the feeder line is good.

Check whether there is standing wave alarm from CDU.

Check the running conditions of secondary power supply boards

See whether they are operating normally No alarm.

1.4 Quarterly Maintenance Instructions


Primary power check Measure the output voltage and the voltage of each battery, and check the aging of DC power cable.

Output voltage <-43.5V

Battery voltage error < 0.3V

Check running conditions of fan Check whether the fan runs normally or whether there are alarms No alarm

Road test Use the testor mobile station to test the switch-over function and the coverage.

VSWR test Check the CDU VSWR alarm indicator

Test whether the transmitting power is normal.

Check alarm collecting device Humidity, temperature, fire alarm etc.



1-10

1.5 Yearly Maintenance Instructions


Check running conditions of channel

Use the testor mobile station to test the communication conditions of respective channels. Observe whether there are call drop, call interruption, noise and single-sided communication, and make record for future reference.

Cabinet cleanness Tools: vacuum cleaner, alcohol, towel etc.

Set strict operation regulations to avoid mis-touching switch or power supply accidentally.

Check base station output power Measure TRX transmitting power. Check whether it is consistent with the BSC setting.

Earth resistance test and grounding cable check

1. Measure earth resistance with an earth resistance meter.

2. Examine whether the connectors of respective grounding cables are loose and check their aging condition.

Check the waterproof conditions of the connectors and lightning grounding clips

Check the external part or untie the insulating tape to have a check Reseal it with the same material!

Check the firmness of antenna and tower top amplifier and the tilting angle of the antenna

1. Screw up the nut again with a wrench.

2. Use an angle meter to check the titling angle.

Do not apply too much force when screwing up the nut with the wrench.



1-11

1.6 Return Loss, VSWR and Reflection Coefficient

Return loss (dB) VSWR Reflection coefficient (Γ)

4 4.41943 0.63096

5 3.56977 0.56234

6 3.00952 0.50119

7 2.61457 0.44668

8 2.32285 0.39811

9 2.09988 0.35481

10 1.92495 0.31623

11 1.78489 0.28184

12 1.6709 0.25119

13 1.57689 0.22387

14 1.49852 0.19953

15 1.43258 0.17783

16 1.37668 0.15849

17 1.32898 0.14125

18 1.28805 0.12589

19 1.25276 0.1122

20 1.22222 0.1

21 1.19569 0.08913

22 1.17257 0.07943

23 1.15238 0.07079

24 1.13469 0.0631

25 1.11917 0.05623

26 1.10553 0.05012

27 1.09351 0.04467

28 1.08292 0.03981

29 1.07357 0.03548

30 1.06531 0.03162

31 1.058 0.02818

32 1.05153 0.02512

33 1.0458 0.02239



1-12

Return loss (dB) VSWR Reflection coefficient (Γ)

34 1.04072 0.01995

35 1.03621 0.01778

36 1.03221 0.01585

37 1.02866 0.01413

38 1.0255 0.01259

39 1.0227 0.01122

40 1.0202 0.01

41 1.01799 0.00891

42 1.01601 0.00794

43 1.01426 0.00708

44 1.0127 0.00631

45 1.01131 0.00562

46 1.01007 0.00501

47 1.00897 0.00447

48 1.00799 0.00398

49 1.00712 0.00355

50 1.00634 0.00316



1-13

Formulas for calculating reflection coefficient Γ, return Loss RL, and VSWR is displayed in the following table:

Reflection coefficient Γ VSWR Return loss (RL) Z1=Z2=Z3

Γ=UreflectedUforward

VSWR=

Uforward+UreflectedUforward－Ureflected

VSWR=Uforward+UreflectedUforward－Ureflected

Γ=1

alog( )R20 VSWR=

1+Γ1−Γ

RL=

1Γ

20log

Γ=VSWR−1VSWR+1

VSWR=

alog( ) −1R20

R20alog( )+1

RL=VSWR+1VSWR−1

20log


BTS MaintenanceChapter 2 Fault Analysis and Location

2-1

Chapter 2 Fault Analysis and Location

2.1 Communication Fault

2.1.1 Introduction to Mobile Station's Search for the Network

Mobile stations may operate either in the HPLMN (Home Public Land Mobile Network), or in other PLMNs. There are two modes for a mobile station to select the serving network:

Automatic network search Manual network search

After a mobile station (with a SIM card or after a SIM card is inserted) is powered on, the mobile station searches for the PLMN it logged in last time. If the PLMN does exist, the mobile station attempts to log in.

If the login succeeds, the mobile station will be served by this PLMN. If the login fails because no appropriate cell is available, the mobile station will

search at least thirty 900M channels or forty 1800M channels (The process of searching the radio frequency channels actually includes the selection of PLMN).

If the login fails due to the failure of location updating, then it is unnecessary to select the above mentioned frequency channels. However, the available PLMNs must be displayed to the subscriber. Subscribers can then select network in automatic or manual mode.

In automatic network search mode, the mobile station selects the network according to the priority of PLMN list it has saved. While in manual mode, the mobile station displays the available networks to the subscriber and tries to log in to the specified PLMN according to the subscriber's selection.

Network search may be affected by the roaming process of the mobile station. This process can be classified into two types:

International roaming Domestic roaming

International roaming: in which the mobile station logs in to other PLMNs in a different country from where the HPLMN is located.

Domestic roaming: in which the mobile station logs in to other PLMNs in the same country where the HPLMN is located in. When the mobile station is roaming across the country, it will search for a HPLMN periodically. To prevent a mobile station from logging in frequently to a prohibited Location Area (LA) during domestic roaming, the



2-2

mobile station saves this LA in a table named "Forbidden Las for domestic roaming" of the mobile station equipment. This table will be cleared when the mobile station is powered off or when the SIM card is pulled out.

In addition, the mobile station saves in its own SIM card some of the PLMNs where services are prohibited. Only when these PLMNs are selected in the manual network search mode and the location updating succeeds can these PLMNs be deleted from the service-prohibited PLMN table.

Failure of mobile station network search indicates the failure in selecting a PLMN or a cell.

2.1.2 Call Failure

I. Fault Description

When the mobile station is powered on and detects a network, the following occur after subscriber dial-up:

1) No ringing at the called MS after dialing though that MS is idle.

2) After dialing, the caller hears the ring-back tone, but the call is automatically disconnected.

3) After dialing, the caller hears the ring-back tone, but the call is automatically disconnected when the called answers.

II. Fault Analysis and Location

The failure of an MS in originating calls might be related to the fault of BTS, BSC, MSC or the PSTN.



2-3

III. Troubleshooting Procedure

No

Yes

No

YesNo

YesNo

YesANo

B

Yes

Start

Check Abis interface

Immediateassignment

Assignmentis over

Radio linkfails

Check the measurement

SDCCHavailable?

TCHFavailable?

Re-configure or increasethe cell capacity

Check the setting ofpaging parameter

Check Abis interface

data mapping relationship

Re-configure or increasethe cell capacity

report



2-4

Receiving qualityis too poor

B

Yes

Possible causes:1. Improper BTS connection 2. Poor TMU clock precision3. Too much air interference4. BSC clock is not accurate enough5. Problems with antenna and feeder system

No route at network side YesPossible causes:

2. TC board abnormal3. A-interface blocked4. MSC unable to obtain the No. Of roaming subscribers5. Some routes are blocked at MSC side

No

1. Incorrect connection of BSC switching

No

Other causes

Possible causes:

End

FTC program abnormal

A

Figure 2-1 Troubleshooting procedures for call failure

To clear the faults in originating calls, follow the instructions below:

1) Trace and check Abis interface message via the interface in BSC maintenance console.

2) If the immediate assignment fails, check if any assignment failed because SDCCHs are insufficient.

Y The cell capacity is not large enough.

In this case, re-configure or expand the cell capacity.

N The failure of immediate assignment may be caused by data configuration errors.

In this case, check the setting of paging parameters of the cell at the data management console.

3) If instead of immediate assignment failure there is TCH assignment failure, check whether the TCHs are insufficient.

Y The cell capacity is not large enough.



2-5

In this case, re-configure or expand the cell capacity.

N Check Abis interface data mapping relationship at the data management console.

4) If the radio link failure occurs after the TCH channel is established, observe the measurement report on the channel before the failure.

Poor quality of BTS or MS signals may be the result of the following factors:

Improper BTS connection Low TMU clock precision Too much air interference BSC clock not accurate enough Problems with the antenna and feeder system Blind spots in network coverage

The causes for absence of route at network side that causes the disconnection of links may be:

Connection error of BSC switching network Abnormality of FTC board Blocking of A-interface Failure of MSC in get roaming subscriber number Blocking of some routes at MSC side

2.1.3 No Voice Heard after the Call is Connected

I. ault Description

There is ringing at the called mobile station, but no voice is heard when the called subscriber answers to the call.


The ringing at the called mobile station indicates that the signaling flow is normal. The voice generation failure may be related to multiple aspects:

1) The failure of corresponding timeslots of FTC, which is the only place where the voice can be converted from voice signals of 16K into that of 64K.

2) Switching network failure, which disables proper switching of voice timeslots.

3) Activation failure of DTX voice transmission.

4) Call re-establishment failure, which causes the signaling course being switched over before the time specified in data configuration, but the switching circuit did not receive the indication of change properly, therefore, the circuit failed to react to the change.



2-6

5) Abnormality of TMU board.


1) Check the occupation of network board timeslots to see whether the network is distributed correctly, i.e., check whether both TCHs have been switched over correctly.

2) Switch off the DTX to see whether the fault reappears.

3) Check signaling analyzer or Abis signaling interface tracing through BSC maintenance console to see whether there are any messages about call re-establishment failure.

4) Reset TMU board to see whether the phenomenon reappears.

5) If the phenomenon persists, there may be erroneous switching at the fixed network side.

6) Plug in/pull out or replace FTC board to see whether the phenomenon reappears. If not, it is the board that fails.

2.1.4 Unidirectional Talk


Mobile station can make calls, but:

1) When both the two parties use an MS for conversation, one of them cannot hear the other.

2) When one of the two parties uses an MS and the other a fixed phone for conversation, one of them cannot hear the other.


Judging from that one of the two parties can hear the other, the signaling flow is normal.

Then, this fault may be caused by:

1) Mobile phone transmitter fault.

2) Activation failure of DTX voice transmission.

3) GNET board exchange error, which disables the up-link of one party from being switched properly to the down-link circuit of the other party.

4) Some links on FTC Board are blocked.



2-7


1) Does this occur repeatedly to some MSs? If so, the transmitter function of the mobile station may be faulty.

2) Switch off the DTX to see whether the fault still exists.

3) View the occupation status of GNET board timeslots to see whether the circuits are switched normally by querying GNET board status on BSC maintenance console.

4) Trace and query the circuit status at MSC. If some circuit ports are always disconnected, block the port or replace FTC board.

5) Check whether there is any Public network faults.

2.1.5 Poor Voice Quality


The mobile station can detect a network after it is powered on, and can make/receive calls, but the voice quality is poor.


If the mobile station can make calls, the signaling channels are normal.

Poor voice quality indicates that the voice BER (Bit Error Ratio) at the radio interface is high. Generally, high BER during decoding at the base station is caused by low receiving level or degrading of clock precision.


1) Determine whether the fault is related to the TRX or any timeslots of it. If yes, reset or replace the TRX.

2) Check the strength of MS signal. If the signal is weak, it could be that the receiving level is too low. In this case, make a call in the open space.

3) With the help of signaling analyzing instruments or by tracing Abis interface messages at BSC maintenance console, determine which of the two is unsatisfactory, the uplink level, or the down link level.

If the up-link level is poor, please check whether the power supply of the mobile station is sufficient.

If the down link level is poor, the fault may be caused by the coverage. In this case, check whether the radio frequency is degrading or whether the subscriber is at the edge of a cell.



2-8

4) Ask the subscriber to check whether the power supply of the mobile station is sufficient.

5) If the receiving level is OK but BER is high, the fault may be caused by the instability of the clock. In this case, try to relocate the network by measuring the precision of BTS, BSC clocks.

6) If both the receiving level and BER are OK, check the interference on the transmission links between BSC and BTS.

7) Check antenna and feeder system.

2.1.6 Conversation Interruption


Conversation interruption during the normal process of a conversation of a mobile station refers to the fact that there is no voice heard for a while, or the voice is intermittent.


Conversation interruption is related to the faults of BTS, BSC, MSC or PSTN. It possibly results from the negative impact of the environment or the degrading of equipment performance.


The fact that voice is heard during the conversation indicates that the speech channel has been established and kept in service. But the intermittence of the voice indicates that there are some break points in the link, which hinders the normal transmission of the voice to the receiving end and causes conversation interruption.

Follow the instruction below to clear the fault:

1) Check whether the FTC board is normal. If not, reset it (or replace it if necessary).

High BER at the network side and BTS side may be the result of low precision of BSC or BTS clock, or the interference between transmission links.

2) Check whether the TRX sensitivity is too low.

If yes, replace the TRX.

3) Check whether the fault is caused by co-frequency interference among cells.

If yes, reconfigure cell data.



2-9

4) Check whether the receiving antenna and feeder are normal.

If no, check whether there is water-penetration, corrosion or short-circuit with the receiving antenna and feeder, and take corresponding measures.

5) Check whether the mobile station is located too far away from the BTS, or in blind area, and take corresponding measures.

6) Check if the fixed network equipment is abnormal, and take corresponding measures.

2.1.7 Cross Talk


The voice from another channel is heard in the course of normal conversation of the mobile station.


Cross talk is most possibly caused by timeslot exchange error, i.e., the signals of another speech channel are switched to the timeslot currently engaged in the conversation. As a result, the subscriber affected may either hear the voice from the ongoing conversation among some other subscribers, hear nothing at all, or cannot be heard by the other party engaged in the conversation with him.


1) Check GNET board networking to see whether there is any missing or duplicated networking.

2) Check the exchange of timeslots at the switch side. Fault of this exchange is common in fixed network.

2.1.8 Mobile Station Frequently Disconnected from the Network


1) When the MS is idle, it happens frequently that the MS sometimes display the network it accessed and sometimes not, indicating that the MS is frequently disconnected from the network.

2) The MS is frequently disconnected from the network while in the course of communication.



2-10


When the MS receives system message and calculates the parameters such as C1, it finds that the cell where it is located no longer meets the requirements of the protocols. However, no other cells are detected appropriate to serve as the substitute. In this case, the mobile station disconnects from the network.


1) Check whether the system message is sent properly, whether the reselected parameters of the cell and the parameters of random access control changes frequently.

2) Check with the tester MS whether the value of C1 displayed on the MS is too small. If yes, check whether the parameters that may affect the value of C1 are set properly, such as MS RXLEV_ACCESS_MIN, MS maximum transmission power allowable, etc. Check the up-link and down-link receiving levels to see whether the MS is located in an area of poor coverage.

3) Check whether the BTS output is stable. If not, check whether the TRX output is normal or whether the antenna is fixed in a stable manner.

2.1.9 Immediate Assignment Rejection


From Abis interface, it can be observed that immediate assignment rejection message is sent on CCCH channel in the course of SDCCH channels assigning.


This fault is caused by the absence of SDCCH channels available for the assignment.


1) Check whether BSC data configuration is correct, such as radio channel configuration table, and so on.

2) Observe at BTS maintenance console whether SDCCH channels are blocked or whether they are available. Unblock them if they are in ‘BLOCKED’ state.



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2.2 Network Fault

2.2.1 Mobile Station Fails to Find a Network


1) The message 'No Network' is displayed at the MS.

2) There is no display at the MS at all.

3) There is no home PLMN in the network list displayed at the MS.


1) The cell is not in service

At the BTS maintenance console, select [Obtain Cell Attributes] to view the information of the corresponding cell.

If it is prompted that 'Cell is not initialized', the cell then is not in service.

If the information on the corresponding cell is displayed, the cell then is already in service.

2) Trace Abis interface message flow and observe whether there is any channel request

If no channel request is detected to be directed to this cell, either the network or the individual MS may be faulty.

The causes of network fault may be:

BS hardware fault

At the BTS maintenance console, check whether the operating status or the status indicators of respective boards are normal. Check if the attributes of TRX and TMU boards are consistent with the data configuration of the data management console, and whether the BSC clock is locked by the clock board. If all these items are normal, test whether the power output of the antenna and feeder is normal.

Incorrect system message

Check whether the configurations of CI, LAI, BSIC and CCCH are consistent with those in the radio channel configuration table.

The causes of individual MS fault may be:

The MS is not located in a suitable place and RXQUAL (signal quality) is poor or RXLEV (signal level) is too low. Move the MS to an open place and try again.

The battery of the MS is low.



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1) Initializing the cell and the site

If the cell is not in service, reset the site hierarchically.

Please note that this may affect the other cells under this site.

During the initialization, the progress of the initialization will be displayed.

Base station initialization is embodied by the initialization of site and cell.

Site initialization procedure:

Set site logic object Set site hardware object Set site extended attributes Establish multi-point connection Site activation

Cell initialization procedure:

Create TEI Establish signaling channel connection Establish traffic channel connection Set cell attributes Set cell extended attributes Set RC attributes Set RC extended attributes Set channel attributes Set cell alarm threshold Cell activation Wait for cell status change report

The result of these two types of initialization will be displayed at the maintenance console on a realtime basis. If the operation succeeds, a solid star will be displayed. If the operation fails, a hollow star together with the cause of failure will be displayed.

2) Clearing hardware problem

If the system messages are wrong, correct them. Set the whole table and validate them with the help of dynamic data configuration.

2.2.2 Mobile Station Fails to Access the Network


1) The MS displays 'No Services' or 'Only Emergence Call', or does not display anything at all.



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2) One or more networks are detected when manual searching of networks is performed.

3) From Abis interface, no message can be observed or 'Location Updating Rejection' is observed.

4) The indicator of OML link of LAPD board flashes quickly or is off.

5) The indicator of RSL link of LAPD board flashes quickly or is off.


1) No SIM card is installed. Please insert a SIM card.

2) The battery of the MS is low. Please recharge the battery.

3) The cell is not in service. For details, refer to the troubleshooting procedure of this section.

4) If RSL is disconnected, the indicator of RSL link on LAPD board flashes quickly or is off. For details, refer to '4 Signaling Fault' of this module.

5) If OML is disconnected, the indicator of OML link on LAPD board blinks quickly or is off. For details, refer to '4 Signaling Fault' of this module.

6) System message is incorrect.

7) If a dual-band MS is forcedly set as a single band 1800M (or 900M) MS, then it can not access the 900M network (or 1800M network).

8) If some internal settings of the MS are improperly modified, the MS may fail to access the network.


If the cell is not in service, then perform level-4 resetting to the site and check whether the initialization flow is normal.

1) Is the cell activated?

Y Step 3).

N Step 2).

To judge whether the cell has been activated:

Select [Obtain Cell Attributes] to view for the information of the corresponding cell at the base station maintenance console. If it is prompted 'Cell is not initialized', the cell has not been activated. If attribute information about the cell is displayed, the cell has already been in service.



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2) For the cell that has not been activated, reset the site that the cell belongs to.

Please note that this will affect the conversation of other cells under the site.

During the initialization, the progress indication of respective stages of the initialization will be displayed.


Site initialization procedures:


Cell initialization procedures:

Create TEI Establish signaling channel connection Create traffic channel connection Set cell attributes Set cell extended attributes Set RC attributes Set RC extended attributes Set channel attributes Set cell alarm threshold Cell activation Wait for the cell status change report

The result of these two types of initialization will be displayed at the maintenance console in real time. If the operation succeeds, a solid star will be displayed. If the operation fails, a hollow star along with the causes of failure will be displayed.

If there is any data error in the initialization, check the corresponding data configuration.

If the initialization can not be executed, there is a configuration error in the board corresponding to the main control board of the base station. Check the board and return to Step 1).

3) If the cell has already been in service, check whether the clock signal of the cell and TRX board corresponding to BCCH are normal. If they are not, please take corresponding measures.

How to check:

Select [Equipment Status Query] at the maintenance console to view the board status.



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If the icon of the board is red, the board is abnormal. In this case, check whether the hardware of the base station, the communication between TRX and TMU, and whether each board is normally powered on.

4) If the MS is a dual band one, but forcedly set to single band mode, change back into dual band mode.

5) If the MS is improperly set, restore the ex-factory default setting.

2.2.3 MS Frequent Location Updating


When powered on, the MS can locate the network and make/receive calls. But the voice quality is poor because the MS updates its location frequently.


Location update of an MS takes place when:

1) It is moved into a new location area.

2) It is time for a regular location update.

3) It is powered on.

Frequent location updating usually results from improper data configuration.


1) Check the interface signaling. If 'Normal location updating', then the MS may be located on the edge of a boundary area where multiple location areas are overlapped (which is a rare case). Please try to move the MS forward to any direction.

2) If the interface message 'IMSI ATTACH' appears frequently, and the MS is not powered on and off frequently, check whether the MS RXLEV is so low that the MS fails to receive base station messages and is thus disconnected from the network.

3) If frequent MS location updating is periodical, then the system message may be abnormal and the location updating period may be set too short. Please check whether the MS receives system message (T3212) correctly. Modify the value of T3212 in the system message.

Check if the location area codes in different system messages are consistent.



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2.3 Loading Fault

2.3.1 Software Loading Failure


If software fails to be loaded to the base station, and the interface does not prompt on the successful completion of software loading, it indicates that the software of the new version is not loaded to the base station.

II. Introduction to Software Loading

In BS software loading, the specified software is loaded to the base station through a remote maintenance console or the local MMI to upgrade the software of the base station.

Files that can be loaded and activated are the ones named in the format of *.bin. The loading of TRX software is actually the loading of 7 files that are bundled together. TMU uses OM software.

The interface of software loading is shown in Figure 2-2:

Figure 2-2 [SW Download] interface

In this interface, set all items of the software to be loaded, including file name, sending window size, version, and file ID (file type), and then click <Begin> to start the loading



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Caution:

The software loaded will not take effect until it is activated.

Interface description:

[File ID]: Identifier of various types of board software of the base station. Software No. varies with the types of boards. The file ID must match with the software. TRX_MAIN is the running software for TRX, and TMU_MAIN that of TMU.

[Version]: Identifies the software of different versions for the same type of boards.

[File Name]: The path and file name of the file loaded.

[Send Window Size]: The number of frames of the messages sent by TMU between two responses. Generally it can be set as 49.

After the software is successfully loaded, the interface of software loading will be as shown in Figure 2-3. The prompt 'Load SW successfully' will be displayed in the message bar at the bottom of the interface [SW Download].

If the loading does not proceed as described above, it is not successful.

Figure 2-3 Load SW successfully

III. Fault Analysis and Location

1) Check the channel for the software loading.



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If the software is loaded via a local MMI, check whether the serial port connection is normal.

If the software is loaded via a remote maintenance console, check whether the network connection is normal, and whether E1 line connection is correct.

2) Check whether the management authority is correct. If it is loaded at a local end, the management authority should be obtained at the local end. If it is loaded remotely, the management authority should be released at the local end.

3) Confirm whether the selection of software type is correct. For example, if the loaded software is TRX software, but the selected software type is not TRX_MAIN, then the loading will fail.

IV. Troubleshooting Procedure

1) Make sure that the line connection is normal.

2) Make sure that the management authority is correctly set.

3) Make sure that the loaded software matches the selected type.

4) Make sure that the version No. of the loaded software is correct.

2.3.2 Base Station Initialization Failure


Base station initialization cannot be normally completed.

II. Introduction to Base Station Initialization


1) Site initialization procedures:


2) Cell initialization procedures:

Create TEI Establish signaling channel connection Establish traffic channel connection Set cell attributes Set cell extended attributes



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Set RC attributes Set RC extended attributes Set channel attributes Set cell alarm threshold Cell activation

Corresponding commands or data configuration is sent to the base station during different stages of the initialization.


For site initialization error, check the corresponding data configuration, the TMU board and the maintenance link.

For cell initialization error, check the corresponding data configuration, the TMU board, the maintenance link and the corresponding board.

Check if the bit error rate on the transmission cable is too high or if there is any transmission fault.


1) Check the corresponding data configuration step by step according to the erroneous initialization. Correct errors if there is any.

2) Check if the corresponding boards and the maintenance links are normal.

3) Check if the maintenance link are blocked.

Listed below is an explanation of the prompts on initialization errors:

a. 'Data configuration error' and 'Message does not match the physical configuration': there are errors in the data configuration of BSC data management console. Please check the corresponding data configuration.

b. 'Communication timeout': BTS does not respond within the specified time. After this prompt appears, BSC will re-send the message. If the fault repeats, the transmission link between BSC and BTS is disconnected or a fatal error has occurred to the TMU of BTS.

c. 'Message structure error', 'Message type error', 'Illegal object type', 'Unsupported object type', 'BTS No. error', 'TRX No. error', 'Illegal attribute ID', 'Unsupported attribute', and 'Parameter exceeds the boundary': there are errors with the commands sent by BSC, which may be caused by BSC fault. The problem 'Parameter exceeds the boundary' may possibly be caused by incorrect data configuration.



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2.4 Signaling Fault

2.4.1 OML Link Blocked


While querying the corresponding maintenance link from BSC maintenance console, it is detected that the signaling link status corresponding to OML link is not in multi-frame link-setup state.

II. ntroduction to OML

OML link is the link for maintenance message between BSC and BTS.


1) Check the status of the corresponding link.

2) Check whether the corresponding data configuration is correct.

3) Check whether the corresponding LAPD board is in normal position.

4) Check whether the BIE board of BSC are in normal position, whether the corresponding E1 line and HW line are well connected, whether the status of the corresponding E1 port of BIE board is normal.

5) Check whether the status of TMU board of the base station is normal.


1) If the corresponding OML link is in 'TEI unallocated' status, first check whether the corresponding data configuration is correct.

2) Check whether the corresponding data configuration is correct and consistent with hardware configuration.

3) Check whether LAPD board is in normal position.

4) Check whether the corresponding BIE board status is correct, and whether HW line and E1 line of the board are connected properly. If the corresponding E1 port status is abnormal, HW line or E1 line might be wrongly connected.

5) Check whether the status of BIE board of the base station is correct.



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2.4.2 RSL Link Blocked


While querying the corresponding signaling link via the BSC maintenance console, it is detected that the link is not in multi-frame link-setup state.

II. Introduction to RSL Link

RSL link is the channel for signaling message between TRX and BSC.


1) Check the status of the corresponding signaling link. If it is not in multi-frame link-setup state, specify what status it is in.

2) Check whether the corresponding data configuration of the link is correct.

3) Check the BIE board of BSC to see whether the corresponding E1 line and HW line are well connected, and whether their status is normal.

4) Check whether the status of TMU board of BTS is normal.

5) Check whether the software of the cell is activated.

6) Check whether TRX board works normally.

7) Check whether the 900M/1800M attributes of TRX are correct.


1) If links are in 'TEI unallocated' status, check whether the data of the corresponding link are configured correctly.

2) If the link is in disconnected status, please check whether the data of the corresponding link matches the configuration of the hardware. If not, adjust either the data configuration or the hardware configuration to make them match.

3) Check the status of the BIE board of BSC. Check whether E1 line and HW line are well connected. If not, please connect them properly, and then recheck whether the corresponding status recovers normal.

4) Check whether the corresponding LAPD board is in right location, and whether its status is normal, and whether other links have been established.

5) Check whether TMU board status to see if it is normal.

6) Check whether the software of the cell is activated, whether it is in normal running.

7) Make sure that 900M /1800M TRX is inserted in a proper slot.



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8) Check whether the connector on the BTS cabinet top is well inserted.

2.5 Antenna and Feeder System Fault


The uplink and downlink signals detected are inconsistent with the standard parameters.

II. Introduction to the Antenna and Feeder System

The antenna and feeder system is used to provide duplex radio channels between MS and BTS.

A radio channel from BTS to MS is defined as a downlink channel, while one from MS to BTS an uplink channel.


1) Poor downlink signal

2) Unstable downlink signal

3) Poor uplink signal


Poor downlink signal

1) Check whether the output of TRX OUT port on TRX module (including power amplifier) is normal. If not, replace TRX module.

2) Check whether the output of TX/RX_ANT port on CDU module is normal. If not, replace the CDU

Caution:

The prerequisite to the above procedures is that the transmit cable from TRX to CDU is not faulty.

3) Test the antenna VSWR (voltage standing wave ratio) from 1/2” jumper connector connected with TX/RX_ANT port of CDU module. If it is normal, check the pitch angle of the antenna and adjust it to an appropriate angle.



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4) If the VSWR at testing antenna end, tested from 1/2" jumper connector, is abnormal, check section by section the VSWRs of respective connection ports of the connecting cable (including tower-top amplifier, lightning arrester) between this port and the transmitting antenna till the causes that worsen the VSWR are found. The causes may be poor connection of connectors, water leakage due to poor waterproofing of connectors, high VSWR of the antenna and feeder lightning arrester, high VSWR and water penetration of the antenna etc. Then take corresponding measures to clear the fault according to the different causes.

Unstable downlink signal

1) Check whether the output (PA OUT port) of TRX module (including power amplifier) is stable. If not, replace the TRX module.

2) Check whether the outdoor antenna and feeder system is reliable, and make sure that the antenna and feeder do not sway with wind too much.

Poor uplink signal

1) Check whether CDU has tower-top amplifier alarm (TTA). If so, replace the tower-top amplifier. CDU tower-top amplifier alarm can be obtained by viewing the panel indicator and the alarm report from the operation and maintenance console.

2) Check whether CDU LNA gives alarm. If so, replace the CDU module.

3) Check whether the connecting cable from input port TX/RX_ANT of CDU antenna to the top of cabinet is normal. If not, replace the cable.

4) Test the VSWR of antenna and feeder from the top of the cabinet, the procedure is the same as that in step 4 in I (Poor downlink signal).

2.6 Optical Channel Fault


Optical channel alarm and transmission fault.


This fault may be caused by:

1) Fault of the receiving and transmitting optical channel.

2) Loss of 2M analog signals, 2M interface external clock or 2M line signals, or 2M signal alarm.

3) Loss of 2M interface transmitting clock or 2M interface digital signals.

4) Fault of TEU-TES communication.



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1) Check the optical channel between ASU and BSC.

2) Check the E1 wiring of ASU.

3) Check ASU board.

4) Check TES and TEU.

2.7 Board Fault

2.7.1 CDU

I. Sources of Fault Information

TMU fault can be detected from the information gathered from:

1) The alarm box

2) The alarm console

3) CDU indicator status

4) Hardware configuration status panel of the maintenance console

II. Fault Classification

1) High VSWR 1 (VSWR1) alarm

2) High VSWR 2 (VSWR2) alarm

3) Tower-top amplifier (TTA) alarm

4) Low noise amplifier (LNA) alarm


Clear the fault step by step as instructed.

High standing wave ratio alarm 1 (VSWR1)

1) Use a test mobile station to check if the antenna feeder system of the base station can receive and transmit signals properly.

Y Reset the CDU with the force resetting function of the alarm control unit and see whether the reported alarm is false.



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If the signal is intermittent or cannot be transmitted at all, the antenna and feeder system may be faulty. Check the antenna and feeder system. If the fault is caused by the loose contact of the feeder, proceed with Step 2).

2) Test the voltage standing wave ratio of the outdoor antenna feeder system. Check if it is faulty, and determine whether replacement is necessary on the parts of antenna feeder.

Below are the instructions on the testing of the outdoor antenna and feeder system:

a. Start the check from the 1/2 inch jumper connector that is joined to the TX/RX ANT port of CDU. Check if there is any loose contact with the connector.

b. Check if there is a tower top amplifier. If yes, power off the amplifier before further test to prevent short circuiting or other accidents that may damage the instruments.

c. Check the VWSR at the 1/2 inch connector that is joint to the TX/RX ANT port of CDU. If the VWSR is not stable, check section by section the connection between the TX/RX ANT port and the sending end of the antenna (including the tower top amplifier and the lightening arrester) to locate the cause to the unstableness of VWSR.

Normally, unstable VWSR may be caused by improper installation, improper encapsulation that causes water inflow, high feeder system lightening arrester VWSR, high antenna VWSR or water inflow of the antenna.

Take corresponding measures to eliminate faults.

3) If the CDU is found faulty, replace it.

High standing wave ratio alarm 2 (VSWR2)

1) CDU reports alarm to the Background when VSWR2 occurs, and reports critical VSWR2 alarm to the Background if the alarm lasts for more than one minute.

The operation and maintenance unit, after receiving the VSWR2 alarm, sends a command to the TRX to switch off transmitting excitation.

2) Locate the cause of the fault. Repeat Step 2) of the last section 'I. High standing wave ratio alarm 1 (VSWR1)'.

3) If the fault is not yet located at this point, enable TRX transmitting excitation and repeat Step 1) of the last section “I. High standing wave ratio alarm 1 (VSWR1)”.

4) Replace the CDU.

Tower-top Amplifier (TTA) Alarm

1) Disconnect the jumper from the antenna port, and test the antenna and feeder system with a multi-meter. Power on the CDU, and test whether the input voltage is normal. If not, the CDU is faulty. In this case, replace the CDU.



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2) Disconnect the jumper from the antenna port, and tandem the ammeter in the circuit. Power on the tower top amplifier, and check:

Whether the input voltage is as desired Whether the input current is within the range desired

If the input voltage is normal, but the input current is zero, the TTA may be in bypass status and is faulty. In this case, replace the TTA.

3) Replace the CDU.

Low noise amplifier (LNA) alarm

1) Test the gain from the testing coupling port to RX output port of this channel to see whether it is normal. If not, replace the CDU.

2) Reset the CDU with the force resetting function of the alarm control unit.

Execute the force resetting command from the Background to the CDU, and check whether the indication of CDU indicators. Is CDU alarm reported again? If not, the alarm reported formerly may be false.

3) If the CDU is confirmed to be faulty, replace it.

2.7.2 EDU


The fault of EDU can be detected with the information gathered from:

The alarm box The alarm information at the alarm console Status of EDU indicators Hardware configuration status at the maintenance console panel


VSWRA alarm VSWRB alarm TTA alarm LNA alarm



High standing wave ratio alarm A (VSWRA)

1) When VSWRA occurs to EDU, EDU will report the alarm to TMU. When this alarm lasts one minute, CDU will report a critical SWR alarm to TMU; After the TMU



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receives this report, it will automatically send a command to the TRX to switch off transmitting excitation

2) Test to see if the said CDU has transmitting power. If not, go to Step 4); if so, (the TMU does not switch off transmitting excitation), got to Step 3).

3) Use a test mobile station to check if the antenna feeder system of the base station can receive and transmit signals properly.

Y Check whether the reported alarm is false by manually resetting the CDU. If the alarm is false, proceed with Step 5).

N There might be fault with the antenna feeder transmission system.

4) Test the standing wave ratio of the outdoor antenna feeder system to determine whether it is faulty and whether parts of the antenna feeder system should be replaced.

Below are the instructions:

Shake the 1/4-inch jumper and 1/2-inch jumper on top of the cabinet connected with TX/RX_ANT port of EDU, and see if their VSWR is stable.

Test the VSWR at the 1/4-inch jumper connector connected with TX/RX_ANT port of EDU, and shake the 1/4-inch jumper and the 1/2-inch jumper on top of the cabinet to see if the VSWR changes noticeably.

When the VSWR is less than 1.3:1, the VSWR of the antenna feeder system is regarded as normal. When the VSWR is greater than 1.4:1 or the cable is not correctly connected, you may initially conclude that the antenna feeder system is faulty. Adopt the method of antenna feeder system replacement to further make sure if the system is faulty. When this method fails, go to Step 5). If this step shows the antenna feeder system is faulty, please deal with fault in the way of checking the fault of the antenna feeder system.

Caution:

If a tower top amplifier is installed on the feeder line, cut off the power supply of the TTA, and test if the SWR of EDU TX/RX_ANT port exceeds the standard by a large degree.

5) Check if the EDU is faulty

Test to see if the VSWR of EDU TX/RX_ANT port is more than 2.5:1, which is seriously beyond the standard.



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Check whether the VSWR alarm processing function of EDU is abnormal. First reset EDU and power it on again. If after this the alarm is not reported again, the EDU may be faulty. In this case, replace the EDU to see if it is indeed faulty.

6) If the EDU is confirmed to be faulty, replace it.

Standing wave ratio alarm B (VSWRB)

The removal process of this alarm is similar to that of VSWRA.3. Top-tower amplifier alarm (TTA).

1) Reset EDU to see if the TTA alarm disappears. If not, the reported alarm is false. In this case, replace the EDU If the alarm disappears, go to Step 2).

2) Disconnect EDU antenna port with the 1/4-inch jumper. Use a multimeter to check if there is any short-circuiting. If yes, it indicates the antenna feeder system is faulty, and it is necessary to check the feeder line, jumper and tower amplifier to locate the short-circuiting (e.g. those caused by water inflow).

3) Switch on EDU TTA feeding power, and see if TTA alarm occurs to the EDU. If so, it indicates that EDU voltage output is normal (the alarm arises from the shortage alarm of TTA current, which shuts down the voltage. This is normal).

4) Connect a ammeter in series between the antenna port of the EDU and the 1/4-inch jumper. Please be sure to keep good electric contact between the external conductor of EDU antenna port and the external conductor of the 1/4-inch jumper. Switch on the feeding power of tower amplifier and measure whether the feeding voltage is accurate (12V) and see if the current of the feeding power of tower top amplifier stays within the normal work current range of the tower amplifier selected. If the voltage is normal but the current is zero, it indicates the tower top amplifier is in a state of bypass, the tower amplifier has been damaged and thus requires replacing.

Note:

When the conditions for taking this step are not satisfied, an EDU without its tower top amplifier working properly to check if the antenna feeder system that the EDU with alarm fault corresponds to is normal. Here are the instructions: 1) Power off this EDU and disconnect the jumper from it. 2) Connect the jumper of the antenna feeder system to the antenna port of the EDU that works properly. 3) Power on the EDU as well as the tower top amplifier feeding (TCP), and see if alarm is reported on the EDU tower top amplifier. If yes, the tower amplifier is faulty.

5) Check each part of the antenna feeder system to locate the fault. If the tower top amplifier is still faulty, replace it.



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Low noise amplifier alarm (LNA)

1) Test the gain from the testing coupling port to RX output port of this channel to see whether it is normal. If not, replace the EDU.

2) Utilize the forced reset function of EDU alarm control unit.

3) Manually reset the EDU on the terminal maintenance console, and check if the EDU indicator works properly to determine whether the reported alarm is false.

4) When EDU fault is located, replace the EDU.

2.7.3 PBU


Alarm box View alarm console information Observe the status of PBU indicator View hardware configuration status of maintenance console panel


High voltage standing-wave ratio alarm Over temperature alarm Under power alarm Board communication alarm Flash memory alarm EPLD load times alarm EPLD upgrade failure alarm Master clock alarm Slave clock alarm Clock critical alarm



PBU high voltage standing wave ratio alarm

1) Check the connecting cable and connection input from PBU to CDU.

2) Reset PBU.

3) If the alarm continues, replace this PBU.

PBU over temperature alarm

1) Check the equipment temperature and environment control equipment.



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2) Check the operation of rack fans.

3) If all the temperature control equipment works properly, replace this PBU module.

PBU under power alarm

1) Restart the equipment to see if it can be restored.

2) If it cannot be restored, replace the said PBU module.

PBU board communication alarm

1) Check if PBU is powered on.

2) Replace PBU.

PBU Flash memory alarm

1) Replace Flash memory.

2) Replace PBU.

EPLD load times alarm

If the EPLD is erased for times more than the threshold (100 times), this alarm will arise.

PBU EPLD upgrade failure alarm

If EPLD in Flash upgrade software fails to be loaded for three times consecutively, this alarm will occur.

PBU master clock alarm

1) Check TMU clock.

2) Check clock transmission line.

3) Check TDU.

4) View if extended TMU is installed.

PBU slave clock alarm

1) TMU clock.

2) Check the clock transmission line.

3) Check TDU.

4) View if extended TMU is installed.

PBU clock critical alarm

1) Check active and standby clock transmission line.



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2) Check active and standby clock.

3) Replace PBU unit.

2.7.4 PMU


1) PMU indicator status

2) Hardware status display panel on the maintenance console

II. Related Function Units

PMU, power frame backplane distribution line, power module PSU, sensor and its circuitry, battery pack loop.

III. Fault Classification

1) Board power-off

2) Power supply system alarm


Board power-off

In this case, the indicator RUN on PMU board is off, the board does not work, and remote treatment becomes impossible.

First check whether PSU is switched on, and whether VOUT indicator is on. If the indicator is off, then there must be no PSU voltage output. If VOUT indicator is on, measure whether the output voltage is normal. If it does not fall within the operating voltage range, then PSU power supply is abnormal. If it is normal, check whether PMU is properly inserted. If the problem still exists, replace the PMU board.

Power supply system alarm

In this case, the ALM system alarm indicator on PMU panel is on. It indicates that there are faults in the power supply system. These faults can be viewed via the base station maintenance console and they may be power module alarm, power distribution alarm, and environment alarm.

1) Power module alarm Power module fault

First check whether the input voltage and output voltage of the power frame fall within the operating range. If they do not, check the input power supply and output load. If they are normal, pull out the faulty power module from the backplane according to the



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alarm power module address prompted in the base station maintenance console. Then re-insert when all indicators are off. View the base station maintenance console for any module fault alarm. If there is no fault alarm, then the power module has recovered and can be put into use again. If the alarm reoccurs, replace the faulty power module.

Power module protection

The cause is that the power module input voltage exceeds the operating range or the operating temperature is too high. Check whether there is any over/under-voltage in the input power supply. If it is abnormal, repair the input power supply. If it is normal, check whether the operating temperature of the power module is too high or whether the cooling fan is faulty. If all the above are normal, pull out the power protection module from the backplane according to the alarm power module address prompted in the base station maintenance console. Reinsert the module when all indicators are off. View the base station maintenance console for any module protection alarm. If there is no alarm, then the power module has recovered and can be put into use again. If the alarm reoccurs, replace the power protection module.

Power module communication failure

Check whether PMU and PSU are well inserted. If they are properly installed and of good contact, check via the base station maintenance console to see whether the power module quantity and the data configuration of each module address are correct. If correct, check whether all the inserted modules fail in communication. If all fail in communication and yet it is not sure whether the PMU is normal, replace the PMU. If PMU is confirmed to be normal, replace power frame backplane. If communication failure only occurs to some modules, interchange the positions of the power modules of successful communication with those of communication failure. If the modules that previously failed in communication still fail in communication, replace the power module PSU. If the power module of successful communication fails in communication after the interchange, replace the power frame backplane.

2) Power distribution alarm AC input power-off or AC input over/under-voltage

In DC/DC power supply system, check whether module communication is successful. If all fail in communication, refer to Subsection c (Power Module Communication Failure) in Section 1) for solutions. When no power module is installed, check via the base station maintenance console to see whether module quantity is set as 0. Check the AC input distribution in AC/DC power supply system. If the distribution wires are normal and AC input voltage is normal as well, check whether the PMU is well inserted. If it is properly installed and of good contact, first consider replacing the PMU. If AC input power-off alarm still exists, replace the power supply backplane.

DC output over/under-voltage



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View the busbar voltage via the base station maintenance console and compare it with the actual voltage. If the over/under-voltage is caused by measurement error, check whether the PMU is well inserted. If it is properly installed and of good contact, consider replacing the PMU. If the measurement is made correctly, check when there is DC over-voltage alarm whether the power module or power supply input or power load is abnormal. When there is DC under-voltage alarm, check whether the AC input, power module or power supply input, and power load are abnormal.

Battery powered off

If the conditions for batteries being powered off are met, the monitoring module should stop working and no battery powered off alarm should be detected due to single power supply mode. Check whether the power-off contactor is working. Replace it if it is not working.

Battery fuse broken

Check whether the battery loop fuse, contactor and wiring are normal. If no problem is found with the wiring of the battery loop and devices, check whether the PMU is well inserted. If it is properly installed and of good contact, replace the PMU.

System output voltage abnormal

There is wide differences between the busbar voltage and the specified output voltage. If it is a DC/DC system, the problem may come from the power module or the load. Check whether the power module and the load are abnormal. If it is an AC/DC system, the problem may come from battery pack temperature compensation, power module fault or the load. Check via the base station maintenance console to see whether the measured value of the battery pack temperature is correct. If the value is correct, do calculation using the following formula:

Temperature compensation voltage = floating charge voltage – (battery pack temperature - 25) * temperature compensation coefficient

If the battery pack compensation voltage and busbar output voltage calculated deviate within the error range (0.3V), then it is normal. If the deviation is too big, check whether the power module and the load are abnormal. If the temperature sensor measurement value is incorrect and there is no battery pack temperature sensor attached, check whether the PMU is well inserted. If it is properly installed and of good contact, replace the PMU. When there is a battery pack temperature sensor attached, remove the temperature sensor. And if the measured temperature value is the default value 25 °C, then the temperature sensor must be defective. Replace the battery pack temperature sensor. If the measured temperature value of the battery pack is not the default value, the PMU temperature measurement circuit may be faulty. Replace the PMU.

3) Environment alarm Ultra high/low ambient temperature or humidity



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When installing temperature/humidity sensor, check via the base station maintenance console to see whether the measured value is consistent with the actual value. If it is, tackle the environment problem. If the alarm is caused by incorrect measurement, check whether the PMU is well inserted. If it is properly installed and of good contact, replace the sensor first. If the measurement remains inaccurate, replace the PMU. If no temperature/humidity sensor is installed, check whether the PMU is well inserted. If it is properly installed and of good contact, replace the PMU.

Smoke alarm, infrared alarm and soaking alarm

Check whether the PMU is well inserted. If it is properly installed and of good contact, check whether there is any environmental alarm on the site mentioned above. If there is any such alarm clear it. If there is no such alarm, check whether there is any fault in the sensor and its line. If the sensor and its line are normal, replace the PMU.

Door control alarm

Check whether PMU is well inserted. If it is properly installed and of good contact, and no door control sensor is installed, check whether there is short-circuit jumper connector in the door control sensor interface MC on the power supply backplane. If there is not, install short circuit jumper connector. If there is, replace the PMU. If door control sensor has been installed, check the site for any environmental alarm mentioned above. If such alarm exists, solve the on-site environment problem. If there is no such alarm, check whether the sensor and its line are faulty. If they are normal, replace the PMU.

Fan alarm

Check whether PMU is well inserted. If it is well installed and of good contact, check whether the rack feature No. configured in the base station maintenance console is correct. If it is, check whether the fan fault signal input connector has been installed in the fan port of the power supply backplane. Install the connector if it is not installed. If there is a line fault, solve the problem of fan fault signal input line. If everything is normal, replace the PMU.

2.7.5 PSU


1) Alarm box

2) Alarm console

3) PSU indicator status




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1) Power supply alarm

2) Proper power supply unavailable



Under normal conditions, the two green indicators on the power module are on simultaneously, and the red indicator is off.

Note:

When system output load is small, individual modules may not work (i.e., the VO indicator is off) due to current equalization. Yet it should not be considered as a fault.

If the green input indicator (VIN) of the power module is on, while the green output indicator (VO) is off or flashing, check as instructed below

1) Check whether the faulty module is well installed, and whether the two fasteners at the upper and lower sides of the panel are tightly screwed. If not, reinstall the module following the specified module assembly procedure.

2) Check whether the system fan is running normally. If it is not running, turn on the fan.

3) When the fan is running normally, and the green output indicator (VO) remains off, then it may be that the module has not yet received the PMU voltage regulation signal. Please wait for half a minute and observe.

4) If the green output indicator (VO) remains off after the above steps, this module must be faulty.

If none of the three indicators on the module are on, check as instructed below

1) Check the status of other power module indicators in the same system. If all of them are off, check whether the power supply system input busbar (or connector post) is live or whether the connection is loose. If any problem is found, reconnect the input line.

2) If one or module indicators are on or it is sure the power system input busbar is live, check whether the module is properly installed and whether the two fasteners at the



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upper and lower sides of the panel are tightly screwed. If not, reinstall the module following the specified module assembly procedure.

3) If the indicator remains off after the above steps, this module must be faulty.

4) If the green input indicator (VIN) and red indicator (ALM) on the module panel are off while the green output indicator (VO) is on, it means that the module itself can normally output power supply. Please make replacement if spares are available. If no spares are available, this module can still work as before and normal power supply function will not be affected.

If the red alarm indicator (ALM) on the module panel is on while the green output indicator (VO) is off, check as instructed below

1) Check the system monitoring for any input over/under-voltage alarms. If such alarm is found, then it is normal that the red indicator (ALM) is on. When the input voltage resumes normal, the module will also resume its normal operation.

2) If the input voltage is normal, check whether the cooling fan of the system cabinet has stopped running. When the fan has stopped for a long time, over temperature protection will occur to the module. Pull out the alarm module according to the power module replacement procedure. Detach the module from the power system and reinsert it into the power supply system frame a few minutes later when it is cooled. Then the module should work normally, otherwise it must be faulty and replacement is needed.

2.7.6 TES


1) Alarm console

2) TES indicator status


II. Related Functional Units

TMU, TEU, CDU


1) Board powered off

2) Board communication alarm



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Board powered off

In this case, the PWR power indicator on TES board is off. The board does not work and remote treatment becomes impossible.

First check whether PSU is switched on and whether VOUT indicator is on. If the indicator is not on, it means that there is no PSU voltage output. Then check whether the TES power switch of the switch box on top of the cabinet is shut on. If they are all normal, check whether the TES is properly inserted and whether the power cable of the backplane is well connected. If the problem still exists, replace the TES board.

Board communication alarm

In this case, the ALM indicator on TES panel is on, indicating that a communication fault has occurred to the serial port between TES and TEU, and the serial port between the two boards is blocked.

First replace the TES board. If the communication alarm does not disappear, replace the TEU board. If the alarm still exists, replace the CMB backplane.

2.7.7 TEU


1) Alarm console

2) TEU indicator status

3) Hardware configuration status panel of the base station maintenance console


PSU, TES, TMU, Transmission line and E1 line.


1) Board power-off

2) Transmission line alarm

3) E1 link alarm

4) Calls can not be put through


Board power-off



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In this case, all indicators on TEU board are off and the board does not work.

First check whether PSU is switched on, and whether VOUT indicator is on. If VOUT indicator is not on, it means that there is no PSU voltage output. Then check whether the TES power switch of the switch box on top of the cabinet is on, and then whether the PWR indicator of the TES board is on. If they are all normal, check whether TEU is properly inserted. If the problem still exists, replace the TEU board.

When the TEU is used for the optical transmission system, it is a public resource of the whole network. If the transmission is interrupted due to improper operation, serious consequences will arise. Therefore, TEU power-off operation must be done with extreme caution.

Transmission line alarm

In this case, the RUN indicator on TEU panel will indicate fault. For details, refer to the instructions of various interface boards.

Seen from the OMC, transmission line alarm breaks up into transmission line receiving alarm and transmission line sending alarm. Transmission line receiving alarm means that all receiving lines of the board are blocked. Please check the receiving lines.

Transmission line sending alarm means that all sending lines of the board are blocked. Please check the sending lines.

E1 link Alarm

1) Off-board E1 alarm

This alarm means that faults have occurred to the E1 line. Check whether the E1 line connectors are in good contact. E1 line transmits in 75Ω and 120Ω resistance respectively. Check whether the setting of board toggle switch is correct. The default value of the board is 75Ω. Directly connect the receiving end and sending end of the port using a 75Ω coaxial cable to determine whether the board is faulty. If any alarm occurs, it can be determined that the TEU board is faulty. Please replace the board.

2) Intra-board E1 alarm

A fault has occurred within the board. Please replace the board.

Orderwire blocked

Check whether the board has 48V or 24V power supply input, i.e., whether the jumper setting is correct (Jumpers of ASU and PAT are all set to 48V). Replace TEU board. If the problem still exists, replace CMB backplane.



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2.7.8 TMU


TMU fault can be detected from the information gathered from:

1) The alarm box

2) The alarm console

3) TMU indicators



TRX, CDU, PSU, PMU and E1 lines.


TMU fault may be caused by:

1) No power supply

2) System alarm

3) E1 link alarm

4) Clock is in holdover or free-run mode

5) 13M output clock is found to be inaccurate when tested with a frequency meter


Board power-off

In this case, the PWR power indicator on TMU board is off, the board does not work and remote treatment becomes impossible.

1) Check whether PSU is switched on and whether VOUT indicator is on. If the indicator is off, it means there is no PSU voltage output.

2) Check whether the TMU power switch in the switch box on top of the cabinet is on.

3) Check whether the TMU is properly inserted and whether the power cable of the backplane is well connected.

4) If the problem still exists, replace the TMU board.

System alarm

1) The remote maintenance console prompts on OML link fault



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First check whether CPU is normal, i.e., if the RUN indicator on TMU panel stops flashing, CPU is abnormal.

If it is abnormal, replace the board and then check whether the E1 ports connected to BSC are normal, i.e., if Indicators LI1, LI2, LI3 or LI4 on TMU panel are on or flashing, it indicates that faults have occurred to the corresponding E1 ports.

If they are abnormal, refer to Section III 'E1 link alarm (including local alarm and remote alarm)' to solve the problem and then check whether BSC data configuration is correct.

If the problem still exists, replace the TMU.

2) The MMI maintenance console shows the fault of the boards or modules other than TMU

First check whether the board reported to be faulty is really faulty.

Y Refer to relevant chapters or sections to solve the problem.

N There may be communication fault between TMU and this board. In this case, solve the problem according to the following instructions:

a. Check BSC data configuration and the wiring of the backplane.

b. If the problem still exists, replace the TMU board or the board or module that is reported to be faulty.

E1 link alarm (including local and remote alarm)

When some of the E1 ports are faulty, the line alarm indicators LI1, LI2, LI3 or LI4 on the TMU board are on or flashing.

Fault of local E1 port is indicated with the above listed indicators on, while that of the remote E1 ports, with these indicators flashing.

To clear this type of fault, first check whether data configuration and line connection are correct.

For fault of local E1 port, check if the port reported to be faulty is configured and if the E1 cables are connected.

For fault of E1 port that has been configured, connect the receiving and transmitting terminals of the port with a 75 Ω coaxial cable to determine whether the board is faulty. If alarm appears, it may be a TMU fault. Then replace the TMU board.

If the site is configured as in cascading mode, check the data configuration relative to the cascaded sites.

Clock is in free-run mode



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In this case, the PLL indicator on TMU panel is on.

The clock enters free-run mode due to poor stability or loss of upper level clock reference signal.

Check whether the configured clock reference source is introduced by the E1 link or form the external clock.

If the clock reference signal is introduced by the E1 link, check whether there is E1 link alarm.

Y Refer to Section III, 'E1 link alarm (including local alarm and remote alarm)'.

N Test T2M clock on the panel.

If this clock is not very stable, there is fault with the upper level clock. Clear the fault of the upper level clock and TMU will automatically switch to the locked mode.

If external clock is configured, check: 1) whether the wiring is correct, 2) whether there is any external clock, 3) whether the external clock, if any, meets the requirements.

Clear the fault of the upper level clock and TMU will switch to the locked mode automatically.

13M output clock is found to be inaccurate when tested with a frequency meter

Possible causes of this cause include:

1) Upper level clock is not accurate enough.

2) TMU is damaged.

To clear this fault,

1) Check whether T2M signals on the TMU panel are faulty.

Y There is fault with the upper level clock. In this case, clear the upper level clock fault.

Correct the time of the upper level clock, and then:

a. Set the 13M output clock in free-run mode.

b. Send user-defined command to the 13M output clock to adjust the time of it.

c. Check if the 13M output clock returns to normal.

d. If the 13M output clock fails to lock the right frequency within (about) 20 minutes, replace the TMU board.



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2.7.9 TRX


1) Alarm box

2) Alarm console

3) TRX indicator status

4) Hardware configuration status panel of maintenance console


1) Over standing-wave alarm

2) Power alarm

3) Temperature alarm

4) Clock alarm

5) Phase-locked loop alarm

6) DSP alarm

7) FPGA alarm

8) FIFO alarm

9) Frequency hopping bus alarm

10) DBUS bus alarm

11) Power supply alarm

12) TRX no power output



High voltage standing wave ratio alarm

1) Check the connecting cable between TRX and CDU. If there is poor contact or any broken point, replace the cable.

2) Check whether the antenna is installed properly.

3) Replace the TRX if the fault still can not be removed.

Power alarm



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1) Check whether there is power supply alarm.

2) Check whether there is any clock alarm and whether the clock line between TRB and CMB is normal.

3) Check whether TRX is firmly inserted.


Temperature alarm

1) Check the cooling fan. Replace it if it stops running.

2) Check whether the ambient temperature is too high.


Clock alarm

1) Check whether TRX is in good contact with the backplane. Make sure that it is firmly inserted.

2) Replace the TRX. If the problem still exists, replace the backplane.

If all TRXs of this cabinet give clock alarms, then go as follows:

Check whether the wiring is correct. If not, modify the wiring as required. Check whether there is any broken line.

Check whether TDU module and the wire are properly connected and whether there is any fault in TDU module. If there is, replace the TDU module.

Check whether there is fault in TMU module. If there is, replace the TMU module.

Phase-locked loop alarm

1) Check whether there is any clock alarm. If there is, refer to section IV, 'Clock alarm', to solve the problem.

2) Check whether there is any power supply alarm. If there is, refer to section XI, '(Power supply alarm', to solve the problem.

3) Check whether the data configuration of this cell is consistent with the attributes of this cell (GSM900 or DCS1800).


DSP alarm





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3) Check whether the indicators on TRX panel are flashing alternatively. If they stop flashing or they are not on, reactivate TRX software or reset the TRX.

4) Replace TRX if the fault still can not be removed.

FPGA alarm

1) Check clock alarm.

2) Reset TRX.


FIFO alarm



3) Replace TRX.

Frequency hopping bus alarm


2) Check whether there is any DSP alarm. If there is, refer to section VI, 'DSP alarm', to solve the problem.

3) Check whether there is any FPGA alarm. If there is, refer to section VII, 'FPGA alarm', to solve the problem.


DBUS bus alarm

1) Check whether data configuration is correct and whether the cell is in service.

2) Check whether the wiring is correct.

3) Check whether TMU module is in good contact with the backplane.

4) Check whether there is any fault in TMU module.

5) Check whether E1 line connection is proper.

6) Check whether the TRX and the backplane are well connected.

7) Check whether TRX is inserted into the right slot.


Power supply alarm



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1) Check whether the power is switched off.

2) Check the backplane wiring.

3) Replace TRX.

TRX no power output


2) Check whether there is any phase lock loop alarm. If there is, refer to section V, 'Phase-locked loop alarm', to solve the problem.

3) Check whether there is any DSP alarm. If there is, refer to section VI, 'DSP alarm', to solve the problem.

4) Check whether there is any power supply alarm. If there is, refer to section XI, 'Power supply alarm', to solve the problem.



Documents

BTS30 User Manual