Oma000001 Gsm Fundamentals Issue4[1].0

Huawei Confidential. All Rights Reserved

OMA000001GSM Fundamentals

ISSUE 4.0

2 Internal Use

ObjectivesObjectives

Upon completion of this course, you will be

able to:Grasp basic idea of GSM system such as

frequency spectrum, frequency reuse etc.

Grasp the structure of the GSM system and

the protocol used.

Grasp certain numbers that refer to BSS

Grasp the 4 kinds of channel combination

and understand the idea of multi-frame.

Know some radio techniques

Get the idea of EDGE

3 Internal Use

References References

BSS Feature Description

BSS Signaling Analysis Manual

BSC Technical Manual

4 Internal Use

Chapter 1 GSM System Overview

Chapter 2 GSM Network Structure

Chapter 3 Service Area and Number Planning

Chapter 4 Channels on the Wireless Interface

Chapter 5 Radio Techniques

Chapter 6 GPRS & EDGE Introduction

5 Internal Use

GSM system overviewGSM system overview

The GSM system is a frequency- and time-division cellular system, each physical channel is characterized by a carrier frequency and a time slot number

Cellular systems are designed to operate with groups of low-power radios spread out over the geographical service area. Eachgroup of radios serve MSs presently located near them. The area served by each group of radios is called a CELL

Uplink and downlink signals for one user are assigned different frequencies, this kind of technique is called Frequency DivisionDuplex (FDD)

Data for different users is conveyed in time intervals called slots , several slots make up a frame. This kind of technique is called Time Division Multiple Access (TDMA)

6 Internal Use

GSM DevelopmentGSM Development

Standard Protocol for GSM take effect

System was named as Global System for Mobile Communication

GSM system began to provide service in Europe(2G)

Provide services for the whole world

Micro Cell Technique is used in GSM system

1989

1991

1992

1994

1996

7 Internal Use

Cell TechniqueCell Technique

A certain radio coverage area formed by a set of transceivers that

connected to a set of antennas is called a CELL.

Macro Cell

In the beginning , High-Power BTSs are adopted to provide services.

The BTS covers a wider area , but its frequency utilization is not efficient.

So , it can only provide a few channels for subscribers.

Micro Cell

Later the Low-Power BTS joins the system for getting a better service

area with high capacity . At the same time it adopts the frequency reuse

technique to improve the efficiency of the frequency utilization and also

the whole capacity of the network.

Macro Cell and Micro Cell

8 Internal Use

Multiple Access TechniqueMultiple Access Technique

Multiple Access Technique allows many

subscribers to use the same communication

medium.

There are three kinds of basic Multiple Access

Technique : FDMA , TDMA and CDMA.

GSM system adopt FDD-TDMA (FDMA and

TDMA together).

9 Internal Use

FDMAFDMA

FDMA uses different frequency

channels to accomplish

communication.

The whole frequency spectrum

available is divided into many

individual channels (for transmitting

and receiving)，every channel can

support the traffic for one subscriber

or some control information.

Frequency

Time

10 Internal Use

TDMATDMA

TDMA accomplishes the

communication in different

timeslot.

A carrier is divided into channels

based on time. Different signals

occupy different timeslots in

certain sequence , that is , many

signals are transmitted on the

same frequency in different time.Time

Frequency

11 Internal Use

CDMACDMA

CDMA accomplishes the

communication in different code

sequences.

Special coding is adopted before

transmission, then different

information will lose nothing after

being mixed and transmitted

together on the same frequency

and at the same time.Time

Frequency

12 Internal Use

GSM 900GSM 900

Duplex Separation: 45MHzChannel Bandwidth: 200KHz

The Frequency SpectrumThe Frequency Spectrum

Uplink

890 915 935 960MHz

Downlink

13 Internal Use

Duplex Separation: 95MHzChannel Bandwidth: 200KHz

Base Station Receive

1710 1785 1805 1880MHz

Base Station Transmit

DCS 1800DCS 1800


14 Internal Use


Fd(n)=Fu(n)+10259<=n<=293Fu(n)=450.6+0.2(n-259)450.4~457.6460.4~467.6

GSM 450

Fd(n)=Fu(n)+10306<=n<=340Fu(n)=479+0.2(n-306)478.8~486488.8~496

GSM 480

Fd(n)=Fu(n)+45128<=n<=251Fu(n)=824.2+0.2(n-128)824~849869~894

GSM 850

Fd(n)=Fu(n)+80512<=n<=810Fu(n)=1850.2+0.2(n-512)1850~19101930~1990

PCS 1900

Fd(n)=Fu(n)+450<=n<=124

955<=n<=1023Fu(n)=890+0.2n

Fu(n)=890+0.2(n-1024)876~915921~960

R-GSM 900

Fd(n)=Fu(n)+450<=n<=124

975<=n<=1023Fu(n)=890+0.2n

Fu(n)=890+0.2(n-1024)880~915 925~960E-GSM 900

Downlink Frequency

Frequency Point Available

Uplink FrequencyRange (MHz)Frequency Spectrum

15 Internal Use

Frequency ReuseFrequency Reuse

The frequency resource of mobile system is very

limited.

The different Subscribers can use the same

frequency in different places.

The quality of communication must be ensured.

16 Internal Use


7(Site)X 1(Cell) reuse

2

1

2

3

4

5

6

7

17 Internal Use

4 site X 3 cells reuse

1

8

9

210

46

5 3 7

11

12

R


18 Internal Use

Cell TypesCell Types

Omni

1

120degree

12

3

Omni-directional CellOmni-directional Cell

120 Degree Cell120 Degree Cell

19 Internal Use







20 Internal Use

GSMGSM--GPRS Network ComponentGPRS Network Component

GSM /GPRS BSS

BTS

BSC

BTS

BSC

PCU SS7

SMS system

PSTNISDN

Internet,Intranet

MSC/VLR GMSC

HLR/AUC

SGSN

CG BG

GGSN

GPRS Backbone

Other PLMN

MS

MS

OMC

21 Internal Use

Interface Between Different EntitiesInterface Between Different Entities

GSM /GPRS BSS

BTS

BSC

BTS

BSC

PCU SS7

SMS system

PSTNISDN

Internet,Intranet

MSC/VLR GMSC

HLR/AUC

SGSN

CG BG

GGSN

GPRS backbone

Other PLMN

A

Gb

Gi

Gp

C/D/Gs

Gr/Gs/Gd/Ge Gc

Ga

Abis

Um

MS

MS

OMC

22 Internal Use

Mobile StationMobile Station——MSMS

International Mobile Equipment Identity (IMEI)

– Mobile Equipment

MS=ME+SIMMS=ME+SIM

International Mobile Subscriber Identity (IMSI)

– Subscriber Identity Module

23 Internal Use

Subscriber Identity Module Subscriber Identity Module –– SIMSIM

International Mobile Subscriber Identity (IMSI)Temporary Mobile Subscriber Identity (TMSI)Location Area Identity (LAI)Subscriber Authentication Key(Ki)

SIM

24 Internal Use

The Base Station Controller – BSCThe Base Transceiver Station – BTSThe Trans-coder – TC and Sub multiplexer (SM)

BTSBTS

BSCBSC

TC/SMTC/SMBSS

MSC

Base Station Subsystem Base Station Subsystem –– BSSBSS

25 Internal Use

Packet data switchingBridge between SGSN and BSCProvide Pb and Gb interface

BTSBTS

BSCBSC

TC/SMTC/SMBSS

MSC

Packet Control UnitPacket Control Unit----------PCUPCU

GPRS Backbone

PCUPCU SGSNSGSN

26 Internal Use

Mobile-service Switching Center – MSC Home Location Register – HLR Visitor Location Register – VLR Equipment Identity Register – EIR Authentication Center – AUC Echo Cancellor – EC

AUCAUCHLRHLR

MSC/VLRMSC/VLR

PSTN

NSSEIREIROMC

BSS

ECEC

The Network Switching SystemThe Network Switching System

27 Internal Use

MobileMobile--service Switching Center service Switching Center –– MSC MSC

Call ProcessingOperations and Maintenance SupportInterface managementInter-network & Inter-workingBilling

28 Internal Use

Home Location Register Home Location Register –– HLR HLR

Subscriber ID (IMSI and MSISDN)Current subscriber VLR (current location)Supplementary service informationSubscriber status (registered/deregistered)Authentication key and AuC functionality

29 Internal Use

Visitor Location Register Visitor Location Register –– VLR VLR

Mobile Status (IMSI attached / detached /

busy / idle etc.)

Location Area Identity(LAI)

Temporary Mobile Subscriber Identity(TMSI)

Allocating the Roaming Number

30 Internal Use

IMEI is Checked In White List

IMEI is Checked in Black/Grey List

If NOT found

EIR focus on the equipment , not the subscriber!!

•White List•Black List•Grey List

Equipment Identity Register Equipment Identity Register –– EIR EIR

31 Internal Use

OMC Functional ArchitectureOMC Functional Architecture

OS

MMIDB

Event/AlarmManagement

SecurityManagement

ConfigurationManagement

Performance Management

Fault Management

32 Internal Use







33 Internal Use

Service AreaService Area

PLMN service area

......

Service Area

MSC service area...

Location area...

cell

PLMN service area PLMN service areaMSC service area...

Location area...

cell

34 Internal Use

LAILAI

Location Area Identification

The LAI is the international code for a location area.

MCC: Mobile Country Code，It consists of 3 digits .For example: The MCC of China is "460"

MNC: Mobile Network Code，It consists of 2 digits .For example: The MNC of China Mobile is "00"

LAC: Location Area Code，It is a two bytes hex code.The value 0000 and FFFF is invalid.

For example: 460-00-0011

MCC MNC LAC

35 Internal Use

CGICGI

The CGI is a unique international identification for a cellThe format is LAI+CILAI: Location Area IdentificationCI: Cell Identity. This code uses two bytes hex code to

identify the cells within an LAI.For example : 460-00-0011-0001

CGI: Cell Global Identification

36 Internal Use

BSICBSIC

NCC: PLMN network color code. It comprises 3 bit. It allows various neighboring PLMNs to be distinguished.

BCC: BTS color code. It comprises 3 bit, used to distinguish different cells assigned the same frequency!

NCC BCC

BSIC

BSIC（Base Station Identification Color Code)

37 Internal Use

CC: Country Code. For example: The CC of China is "86".NDC: National Destination Code. For example: The NDC of

China Telecom is 139, 138, 137, 136, 135.SN: Subscriber Number. Format:H0 H1 H2 H3 ABCDExample: 86-139-0666-1234

MSISDNMSISDN

CC NDC SNNational (significant)

Mobile number

Mobile station internationalISDN number

38 Internal Use

MCC: Mobile Country Code，It consists of 3 digits .For example: The MCC of China is "460"。

MNC: Mobile Network Code，It consists of 2 digits .For example: The MNC of China Telecom is "00"。

MSIN: Mobile Subscriber Identification Number. H1H2H3 S ABCDEFFor example: 666-9777001

NMSI: National Mobile Subscriber Identification，MNC and MSIN form it together.

For Example of IMSI : 460-00-666-9777001

Not more than 15 digits

3 digits 2 digits

IMSI

MCC MNC MSINNMSI

IMSI IMSI

39 Internal Use

The TMSI is assigned only after successful subscriber authentication. The VLR controls the allocation of new TMSI numbers and notifies them to the HLR.TMSI is used to ensure that the identity of the mobile subscriber on the air interface is kept secret.The TMSI consists of 4 bytes( 8 HEX numbers) and determined by the operator.

TMSITMSI

TMSI: Temporary Mobile Subscriber Identification)

40 Internal Use

IMEIIMEI

TAC FAC SNR SP

IMEI

IMEI: International Mobile Station Equipment Identification

TAC: Type approval code, 6 bit, determined by the type approval centerFAC: Final assembly code, 2 bit, It is determined by the manufacturer.SNR: Serial number, 6 bits, It is issued by the manufacturer of the MS. SP: 1 bit , Not used.Check the IMEI in your MS : *#06#

TAC: Type approval code, 6 bit, determined by the type approval centerFAC: Final assembly code, 2 bit, It is determined by the manufacturer.SNR: Serial number, 6 bits, It is issued by the manufacturer of the MS. SP: 1 bit , Not used.Check the IMEI in your MS : *#06#

41 Internal Use







42 Internal Use

2 30 16 74 52 3

The physical channel is the medium over which the information is carried: 200KHz and 0.577ms

0 1

TDMA FRAME

TimeslotThe information carried in one time

slot is called a “burst”The information carried in one time

slot is called a “burst”

Physical Channel and Logical ChannelPhysical Channel and Logical Channel

The logical channel consists of the information carried over the physical channels

TDMA FRAME

43 Internal Use

Two types of Logical ChannelTwo types of Logical Channel

Traffic Channel (TCH) :Transmits traffic information, include data and speech.

Control Channel (CCH) :Or Signaling Channel, transmits all kinds of control information.

44 Internal Use

Traffic Channel (TCH)Traffic Channel (TCH)

TCHTraffic Channels

Speech

TCH/FS

Data

TCH/HSTCH/9.6 TCH/2.4

TCH/4.8

TCH Traffic ChannelTCH/FS Full rate Speech Channel TCH/HS Half rate Speech Channel TCH/9.6 Data Channel 9.6kb/sTCH/4.8 Data Channel 4.8kb/sTCH/2.4 Data Channel 2.4Kb/s

45 Internal Use

FCCHSCH

CCH (Control Channels)

DCCH

SDCCH

BCH

BCCH Synch. CH.ACCH

SACCHFACCH CCCH

RACH CBCH

PCH/AGCH

Broadcast Control Channel – BCCHCommon Control Channel – CCCHDedicated Control Channel – DCCHAssociated Control Channel – ACCH

Control Channel (CCH)Control Channel (CCH)

46 Internal Use

CCH

BCH

BCCH Synch.

Channels

SCH FCCH

The information carried on the BCCH

is monitored by the MS

periodically when it is in idle mode

BCCH: Broadcast Control Channel

FCCH: Frequency Correction Channel

SCH: Synchronization Channel

Broadcast Control Channel Broadcast Control Channel –– BCCHBCCH

47 Internal Use

CCH

CCCH

RACHuplink

CBCH downlink

PCH/AGCHdownlink

The CCCH is responsible for transferring control information between all mobiles and the network.

RACH: Random Access Channel

PCH: Paging Channel

AGCH: Access Granted Channel

CBCH: Cell Broadcast Channel

Common Control Channel Common Control Channel –– CCCHCCCH

48 Internal Use

CCH

DCCH

SDCCH

FACCH SACCH

DCCH is assigned to a single wireless connection for measurement and handover purpose.SDCCH: Stand-alone Dedicated

Control Channel ACCH: Associated Control Channel SACCH: Slow Associated

Control Channel FACCH: Fast Associated Control

Channel

ACCH

Dedicated Control Channel Dedicated Control Channel –– DCCH DCCH

49 Internal Use

RACH CCCHCCH

SDCCH

SACCHFACCH

TCH/F

TCH/H

DCCH

TCH

DCH

Uplink Logical channelUplink Logical channel

50 Internal Use

FCCHSCHBCCH

PCH

AGCH

BCCH

CCCH

CCH

SDCCHSACCHFACCH

TCH/F

TCH/H

DCCH

TCH

DCH

Downlink Logical channelDownlink Logical channel

51 Internal Use

Allocate signaling channel

FCCHSCHBCCH

PCHRACHAGCHSDCCHSDCCHTCHFACCH

Power-off

Idle mode

Dedicated mode

Idle mode

How to use these channels?How to use these channels?

Search for frequency correction burst

Search for synchronous burst

Extract system information

Monitor paging message

Send access burst

Set up the call

Allocate voice channel

Conversation

Release the call

52 Internal Use

Packet data channel (PDCH)Comprising packet service channel and packet control channel

Packet service channel (PDTCH) Combined into the single-directional service channel

Packet control channelBroadcast control channel: PBCCHPublic control channel: PPCH, PRACH, PAGCHPrivate control channel: PACCH, PTCCH

TCH

BCCH

SACCH

Packet logic channelPacket logic channel

CCCH

TCH

53 Internal Use

GSM Logical Channel CombinationGSM Logical Channel Combination

Main BCCH combination – FCCH + SCH + BCCH + CCCH SDCCH combination – SDCCH/8 + SACCH/8Combined BCCH – BCCH + CCCH +SDCCH/4 + SACCH/4TCH/FR combination – TCH/F + FACCH/F + SACCH/FTCH/HR combination – TCH/H + FACCH/H + SACCH/H

54 Internal Use

Packet logic channels (PDCH) can be combined via the following three modes

Mode 1: PBCCH+PCCCH+PDTCH+PACCH+PTCCH; Mode 2: PCCCH+PDTCH+PACCH+PTCCH; Mode 3: PDTCH+PACCH+PTCCH

In case of small GPRS traffic, GPRS and circuit services use the same BCCH and CCCH in the cell. In this case, only combination mode 3 is needed in the cell

With the increase of traffic, the packet public channel should be configured in the cell. Channel combination mode 1 and mode 2 should be adopted

Combination of Combination of packet logic channelpacket logic channel

55 Internal Use

TDMA Frames

0 1

0 1 2 43 46 47 48 5049

51 – Frame Multi-frames

0 1 10

CONTROL CHANNELS

2 3 4 5 6 7 2 3 5 764

GSM MultiGSM Multi--framesframes

56 Internal Use

GSM MultiGSM Multi--framesframes

TDMA Frames

0 1

0 1 2 43 21 22 23 2524

26 – Frame Multi-frames

0 1 10

TRAFFIC CHANNELS

2 3 4 5 6 7 2 3 5 764

57 Internal Use







58 Internal Use

Power ControlPower Control

Saves battery powerReduces co-channel andadjacent channel interference

8W

0.8W

5WBoth Uplink and Downlink power settings can be controlled independently and individually.

BCCH -------Does not attend Power control

59 Internal Use

DTX and VADDTX and VAD

Voice Activity Detection – VAD

Discontinuous Transmission – DTX

Battery SavingInterference reduction

60 Internal Use

Timing Advance (TA)Timing Advance (TA)

Transmission delay t

Transmission delay t

TA

The mobile phone shouldsend the signal in advance!

61 Internal Use

MultiMulti--path Fadingpath Fading

Diversity

Frequency Hopping

Time Dispersion

62 Internal Use

Diversity Diversity –– WhatWhat’’s Diversity?s Diversity?

Receive diversity provides an effective technique for both overcoming the impact of fading across the radio channel and increasing the received signal to interference ratio.

The former is achieved by ensuring “uncorrelated” (i.e. low enough correlated) fading between antenna branches i.e. not all antennas experience fades at the same time.

63 Internal Use

Kinds of DiversityKinds of Diversity

Time diversityCoding, interleaving

Frequency diversityFrequency hopping

Space diversityMultiple antennas

Polarization diversityDual-polarized antennas

Multi-path diversityEqualizer

t

f

64 Internal Use

Frequency HoppingFrequency Hopping

Frequency

f 0

Frame

f 1

f 2

f 3

f 4

Time

65 Internal Use







66 Internal Use

57.6 kbps

115 kbps

384kbps

2Mbps

GSM

HSCSD

GPRS

EDGE

IMT-2000

9.6 kbps

2G

2.5G

3G

GSM Development EvolutionGSM Development Evolution

67 Internal Use

Data rate of EDGE and GPRSData rate of EDGE and GPRS

8PSKGMSK

9.013.4

15.6

21.4

8.811.2

14.817.6

22.4

29.6

44.8

54.4

59.2

0.0

10.0

20.0

30.0

40.0

50.0

60.0

CS-1 CS-2 CS-3 CS-4 MCS-1 MCS-2 MCS-3 MCS-4 MCS-5 MCS-6 MCS-7 MCS-8 MCS-9

Kbps

GPRS

EGPRS

68 Internal Use

Downlink, 4 TS, MCS-9：

Huawei EDGE Test ResultHuawei EDGE Test Result

69 Internal Use

SummarySummary

The basic idea of GSM The frequency spectrum used in GSMThe structure of GSMCertain service area and numbersSome radio techniques used in GSMEvolution of GSM

SummarySummary

Huawei Confidential. All Rights Reserved

Documents

Oma000001 Gsm Fundamentals Issue4[1].0