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Submitted By :- Ankita SoganiRoll no :- 17Batch :- E.C.E (A-1 )

Under taken at:-

ERICSSION INDIA PVT. LTD.



Global System for Mobile (GSM) is a second

generation cellular standard developed to

cater voice services and data delivery using

digital modulation.



Developed by Group Spéciale Mobile (founded 1982) which was aninitiative of CEPT ( Conference of European Post andTelecommunication )

Aim : to replace the incompatible analog system

Presently the responsibility of GSM standardization resides withspecial mobile group under ETSI ( European telecommunicationStandards Institute )

Full set of specifications phase-I became available in 1990

Under ETSI, GSM is named as ³ Global System for Mobilecommunication ³

Today many providers all over the world use GSM (more than135countries in Asia, Africa, Europe, Australia, America)

More than 1300 million subscribers in world and 45 million subscriber in India.



Improved spectrum efficiency

. International roaming

. Low-cost mobile sets and base stations

. High-quality speech

. Compatibility with ISDN and other telephonecompany services.

. Support for new services

. Q o S



1.Tele Services

Telecommunication services that enable voice communication by mobile phones.

Offered services:- Mobile telephony, Emergency calling

2.Bearer Services

Include various data services for information transfer between GSM and other

networks like PSTN, ISD N etc.

Short Message Service (SMS), fax, voice mailbox, electronic mail,etc.

3.Supplementary Services

Call Waiting

Call Hold

Call Barring

Call Forwarding

Call Conferencing



A cell is the basic unit of a cellular system and is defined as the area of

radio coverage given by one BS antenna system. Each cell is assigned a

unique number called Cell Global Identity (CGI).

advantage

Frequency reuse ² same frequency in many cell sites

Cellular expansion ² easy to add new cellsHandover ² moving between cells

The reuse frequency distance



M acrocells(3 to 35 km)M icrocells(0,1 to 1 km)

Picocells(0,01 to 1km)

Nanocells(1m to 10m

Umbrella cells covers several microcells



Mobile Station (MS)

Mobile Equipment (ME)

Subscriber Identity

Module (SIM)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)

A uthentication Center

( AUC)

Equipment Identity

Register (EIR)



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 ² 20 W 160 character long SMS.

Subscriber Identity Module (SIM)

A llows user to send and receive calls and receive other

subscribed services Smart card contains the International Mobile Subscriber Identity

(IMSI) Encoded network identification details Key Ki, Kc and A3, A5 and A 8 algorithms Protected by a password or PIN Can be moved from phone to phone ² contains key information to

activate the phone



Base Transceiver Station (BTS)

Encodes,encrypts,multiplexes,modulates and feeds the RF

signals to the antenna.

House the radio transceivers of the cell.

Communicates with Mobile station and BSC.

Handle the radio link protocols.

Base Station Controller (BSC)

The BSC is the connection between the mobile station and theMobile service Switching Center (MSC).

Manages Radio resources for BTS. A ssigns Frequency and time slots for all MS·s in its area. Handles call set up. Handover for each MS.



Mobile Switching Center (MSC)

Heart of the network. Manage communication between GSM and other networks. Identify the origin , destination and type of the call. Billing information and collection.

supervises operation of the rest of the network components Mobility management GMSC: Gateway MSC act as a bridge between mobile network and

fixed network.

Home Location Register (HLR)

It acts as a permanent store for a person's subscription informationuntil that subscription is canceled.

The information stored includes:

Subscriber identity

Subscriber supplementary services

Subscriber location information

Subscriber authentication information



Visitor Location Register (VLR)

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

database Controls those mobiles roaming in its area . Database contains IMSI,MSISD N,MSR N,Location Area, authentication key Tracks and periodically updates the database on which phones are turned on

and ready to receive a call.

Authentication Center (AUC)

Authenticate the subscribers. Ciphering keys used to ensure network security. Generally associated with HLR.

Equipment Identity Register (EIR)

Database that is used to track handsets using the IMEI (International MobileEquipment Identity).

Made up of three sub-classes: The White List, The Black List and the GrayList.

Only one EIR per PLM N.



The initial design used the 900 MHz range Uplink to BTS 890 - 915 MHz Downlink to MS 935 - 960 MHz Duplex distance 45MHz Carrier Seperation 200KHz There are 124 channels A nd each channel can carry 8

TDM A users Modulation GMSK Usually an operator does not have access to the full range GSM technology is also used on other frequencies :- 4500,

800, 1800,1900 MHz

Maximum range is 35 kilometers due to timing requirements MS power is max 2 W for the handheld devices



1. MS sends dialled number to BSS .2. BSS sends dialled number to

MSC.3. MSC checks VLR if MS is

allowed the requestedservice.MSC asks BSS to allocateresources for call.

5. MSC routes the call to GMSC.6. GMSC routes the call to local

exchange of called user.7. Answer back(ring back) tone isrouted from called user to MS byGMSC,MSC,BSS.



1. Calling a GSMsubscribers.

2. Forwarding call toGMSC.

3. Signal Setup to HLR.

4. Request MSRN from VLR.

6. Forward responsibleMSC to GMSC.

7. Forward Call to currentMSC.

8. Get current status of MS.10. Paging of MS.12. MS answers.14. Security checks.16. Set up connection.



Mobile telephony

Telemetry System

A utomatic meter reading

Value A

dded Services Other A pplications:-

Call waiting

Call divert

Mail

RoamingSMS

MMS





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