GSM Network Dilip

8/9/2019 GSM Network Dilip

1/21

Presentation on GSMPresentation on GSM

NetworkNetwork


2/21

What is GSM ?What is GSM ?

Global System for Mobile (GSM) is a

second generation cellular standarddeveloped to cater voice services and

data delivery using digital modulation


3/21

GSM: HistoryGSM: History

Developed by Group Special Mobile (founded 1982) which wasaninitiativeof CEPT ( Conferenceof European Postand

Telecommunication )

Aim : toreplacetheincompatibleanalogsystem

PresentlytheresponsibilityofGSM standardizationresides with special

mobilegroupunderETSI ( Europeantelecommunication Standards

Institute )

UnderETSI, GSM isnamedas GlobalSystem forMobile

communication

Todaymanyprovidersalloverthe worlduseGSM (morethan 135

countriesin Asia, Africa, Europe, Australia, America)

Morethan 1300 millionsubscribersin worldand 45 millionsubscriberin

India.


4/21

GSM inWorldGSM inWorld

Figures: March, 2005

37%

1%4%43%

4%

3%

3%

3% (INDIA)

3%

Arab World

Asia Pacific

Africa

East Central Asia

Europe

Russia

India

North America

South America


5/21

GSM in IndiaGSM in India

Figures: March 2005

Bharti

27%

BSNL

22%

Spice4%

IDEA

13%

Hutch

19%

BPL

6%

Aircel4%

Reliance

3%

MTNL2%

BhartiBSNL

Hutch

IDEA

BPL

Aircel

Spice

Reliance

MTNL


6/21

GSM ServicesGSM Services

Tele-services

Bearer orData Services

Supplementary services


7/21

Tele ServicesTele Services

Telecommunication services that enable voice communication

via mobile phones

Offered services

- Mobile telephony

- Emergency calling


8/21

Bearer ServicesBearer Services

Include various data services for information transferbetween GSM and other networks like PSTN,ISDN etc atrates from 300 to 9600 bps

Short Message Service (SMS)

up to 160 character alphanumeric data transmissionto/from the mobile terminal

Unified Messaging Services(UMS)

Group 3 fax

Voice mailbox

Electronic mail


9/21

Supplementary ServicesSupplementary Services

Call related services :

Call Waiting- Notification of an incoming call while on the handset

Call Hold- Put a caller on hold to take another call

Call Barring- All calls, outgoing calls, or incoming calls

Call Forwarding- Calls can be sent to various numbers defined bythe user

Multi Party Call Conferencing - Link multiple calls together

CLIP Caller line identification presentation

CLIRCaller line identification restriction

CUG Closed user group


10/21

GSM System ArchitectureGSM System Architecture

BSC

BSC

MSC

MS

MS

MS BTS

BTS

BTS

GMSC

PSTNISDN

PDN

EIRAUC

HLR

VLR


11/21

GSM System ArchitectureGSM System Architecture--II

Base Station Subsystem (BSS)

Base Transceiver Station (BTS)

Base Station Controller (BSC)

Network Switching Subsystem(NSS)

Mobile Switching Center (MSC)

Home Location Register (HLR)

Visitor Location Register (VLR)

Authentication Center (AUC)

Equipment Identity Register (EIR)


12/21

System ArchitectureSystem Architecture

Base Station Subsystem (BSS)Base Station Subsystem (BSS)

Base Station Subsystem is composed of two parts that

communicate across the standardized Abis interface allowing

operation between components made by different suppliers

1. Base Transceiver Station (BTS)

2. Base Station Controller (BSC)


13/21



Base Transceiver Station (BTS):

Encodes,encrypts,multiplexes,modulates and feeds the

RF signals to the antenna.

Frequency hopping Communicates with Mobile station and BSC

Consists ofTransceivers (TRX) units


14/21



Base Station Controller (BSC)

Manages Radio resources for BTS

Assigns Frequency and time slots for all MSs in its area

Handles call set up

Transcoding and rate adaptation functionality

Handover for each MS

Radio Power control

It communicates with MSC and BTS


15/21


Network Switching Subsystem(NSS)Network Switching Subsystem(NSS)

Mobile Switching Center (MSC)

Heart of the network

Manages communication between GSM and other networks Call setup function and basic switching

Call routing

Billing information and collection

Mobility management

- Registration

- Location Updating

- Inter BSS and inter MSC call handoff

MSC does gateway function while its customer roams to other networkby using HLR/VLR.


16/21


Network Switching SubsystemNetwork Switching Subsystem

Home Location Registers (HLR)

- permanent database about mobile subscribers in a large servicearea(generally one per GSM network operator)

- database contains IMSI,MSISDN,prepaid/postpaid,roamingrestrictions,supplementary services.

Visitor Location Registers (VLR)

- Temporary database which updates whenever new MS enters its area,by HLRdatabase

- Controls those mobiles roaming in its area

- Reduces number of queries to HLR

- Database contains IMSI,TMSI,MSISDN,MSRN,Location

Area,authentication key


17/21


Network Switch

ing SubsystemNetwork Switch

ing Subsystem Authentication Center (AUC)

- Protects against intruders in air interface

- Maintains authentication keys and algorithms and providessecurity triplets ( RAND,SRES,Kc)

- Generally associated with HLR

Equipment Identity Register (EIR)

- Database that is used to track handsets using the IMEI(International Mobile Equipment Identity)

- Made up of three sub-classes: The White List,The BlackList and the Gray List

- Only one EIRper PLMN


18/21

Outgoing CallOutgoing Call

1. MS sends dialled number to BSS2. BSS sends dialled number to MS

3,4 MSC checks VLRif MS isallowed the requested service.If

so,MS

C

asks BSS to allocateresources for call.

5 MSC routes the call to GMSC

6 GMSC routes the call to localexchange of called user

7, 8,9,10 Answer back(ring back) tone is

routed from called user to MS viaGMSC,MSC,BSS


19/21

Incoming CallIncoming Call1. Calling a GSM

subscribers

2. Forwarding call to

GSMC3. Signal Setup to HLR

4. 5. Request MSRN fromVLR

6. Forward responsibleMSC to GMSC

7. Forward Call to currentMSC

8. 9. Get current status of

MS10.11. Paging of MS

12.13. MS answers

14.15. Security checks

16.17. Set up connection


20/21

Thanks !Thanks !


21/21

Questions ?Questions ?

GSM Network Dilip

Documents

Transcript of GSM Network Dilip