GSM ppt

BY SHAILJA YADAV

COMPANY NAME:VIDEOCON

TELECOMMUNICATION LIMITED

Global System for Mobile Communication.

History of companyWhat is GSM?GSM historyGSM servicesGSM architectureGSM techniquesGSM channels

DISCUSSION TOPICS

Type : PublicIndustry : ConglomerateFounded : 1979Founder(s) : Nandlal Madhavlal DhootHeadquarters : Aurangabad, Mumbai, IndiaKey people : Venugopal Dhoot (chairman)Products : consumer electronics, DTH, oil

and gas, color picture tube, mobile phones and telecommunication

Net Income : US $ 90.77 millionRevenue : US $ 2.1 billion

History of company

GSM is a standard for a Global System for Mobile communications. Global System for Mobile communications, a mobile phone system based on multiple radio cells (cellular mobile phone network).

Two main standards are followed: 1. GSM 900 (global system for mobile

communications in the 900 MHz band) 2. DCS 1800 (digital cellular system for the 1800

MHz band)

WHAT is GSM?

Global system for mobile (GSM) is a second generation cellular standard developed to cater voice services and data delivery using digital modulation.

Today’s GSM platform is a hugely successful wireless technology and an unprecedented story of global achievement.

Since 1997, the number of GSM subscribers has increased by a staggering 10 fold. The progress hasn’t stopped there. Today’s GSM platform is living, growing and evolving and already offers and expanded and feature-rich ‘family’ of voice and data enabling services.

WHAT is GSM? (CONTD)

• Developed by Group Spéciale Mobile (founded 1982) which was an initiative of CEPT ( Conference of European Post and Telecommunication ).

• Presently the responsibility of GSM standardization resides with special mobile group under ETSI ( European telecommunication Standards Institute ).

• Full set of specifications phase-I became available in 1990.

• Under ETSI, GSM is named as “ Global System for Mobile communication “

GSM HISTORY

GSM HISTORY (CONTD)

Year Milestone1982 GSM formed 1986 Field test 1987 TDMA chosen as

access method1988 Memorandum of

understanding signed1989 Validation of GSM

system1990 Pre-operation system1991 Commercial system

start-up1992 Coverage of larger

cities/airports1993 Coverage of main

roads1995 Coverage of rural

areas

• Tele-services• Bearer or Data Services • Supplementary services

GSM 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 by the

userMulti Party Call Conferencing

- Link multiple calls together

Basic services provided by GSM

Calling Line ID- incoming telephone number displayed

Alternate Line Service- one for personal calls- one for business calls

Closed User Group- call by dialing last for numbers

Advice of Charge- tally of actual costs of phone calls

Fax & Data- Virtual Office / Professional Office

Roaming- services and features can follow customer from market to market

Advanced Features Provided by GSM

GSM ARCHITECTUREGSM System Network

Mobile Station (MS)

Mobile Equipment (ME)

Subscriber Identity Module (SIM)

Base Station Subsystem (BBS)

Base Transceiver Station (BTS)

Base Station Controller (BSC)

Network Subsystem( NSS)

Mobile Switching Center (MSC)

Home Location Register (HLR)

Visitor Location Register (VLR)

Authentication Center (AUC)

Equipment Identity Register (EIR)

GSM ARCHITECTURE (CONTD)

MSC/VLR

HLR/AUC EIR SC/VM

OMC

BSC

BTSPSTNISDNPSPDN

MS

BSS

MSS

Um

Abis

A

FC

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MSC/VLR

E

Mobile Equipment

• Portable, vehicle mounted, hand held device

• Uniquely identified by an IMEI (International Mobile Equipment Identity)

• Voice and data transmission • Monitoring power and signal

quality of surrounding cells for optimum handover

• Power level : 0.8W – 20 W• 160 character long SMS.

Mobile Station ( MS )

Subscriber Identity Module (SIM)

• Smart card contains the International Mobile Subscriber Identity (IMSI)

• Allows user to send and receive calls and receive other subscribed services

• Protected by a password or PIN• Can be moved from phone to phone –

contains key information to activate the phone

Mobile Station (MS) (CONTD)

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 of Transceivers (TRX) units

Base Station Subsystem (BSS)

Base Station Controller (BSC)

• Manages Radio resources for BTS• Assigns Frequency and time slots for all

MS’s 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

Base Station Subsystem (BSS) (CONTD)

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 network by using HLR/VLR.

Network Switching Subsystem(NSS)

• Home Location Registers (HLR) permanent database about mobile subscribers in a large service area

(generally one per GSM network operator) database contains IMSI, MSISDN, prepaid/postpaid, roaming

restrictions, supplementary services.

• Visitor Location Registers (VLR)

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

Controls those mobiles roaming in its area Reduces number of queries to HLR Database contains IMSI, TMSI, MSISDN, MSRN, Location

Area, authentication key

Network Switching Subsystem(NSS) (CONTD)

• Authentication Center (AUC) Protects against intruders in air interface Maintains authentication keys and algorithms and

provides security 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

Black List and the Gray List Only one EIR per PLMN

Network Switching Subsystem(NSS) (CONTD)

GSM InterfacesThe connections shown in pink are various

interfaces.

GSM MULTIPLE ACCESS TECHNIQUES

FDMADivide available frequency into

channels each of same bandwidth

Each of the providers buys some of these channels and thus the bandwidth for a provider is decided.

Still all the channels even if used together could not provide for all the consumers of the network thus the channels are further multiplexed.

Different signal energies are distributed into different timeslots. So the useful signal is passed only in the specified timeslot.

Each channel is divided into timeslots, each conversation uses one timeslot.

TDMA

GSM CHANNELSChannels are divided into two categories:

Physical channelsThe individual channels carried by radio frequency carrier.Each carrier comprises of 8 time separated channels.

Logical channelsTime dependant virtual channel carried on a single physical

channel.One physical channel may support one or multiple logical

channels. Logical channels are divided into nine types of

control channel and two types of traffic channel, all of which are mapped onto the time slots of the physical channels.

Control channels are divided into three classes, based on how and when they are used: broadcast channels (BCH); common control channels (CCCH); and dedicated control channels (DCCH).

Control / Logical channels