BSNL GSM training presentation

8/4/2019 BSNL GSM training presentation

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GSMOperations & Maintenance

BSNL, Lucknow


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BSNL - History

On October 1st, 2000, the Department of Telecom Operations,

Government of India became a corporation and was christened

Bharat Sanchar Nigam Limited (BSNL).

It is the largest public sector undertaking of India in telecom. Its99.9% exchanges are digital.

In order to manage efficiently and better way U.P. Telecom Circle

was bifurcated into two separate Circles viz., U.P. (East) TelecomCircle with Headquarters at Lucknow and U.P. (West) Telecom

Circle with Headquarters at Meerut.


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GSM - Introduction

Global System for Mobile (GSM) is

a second generation cellularstandard developed to cater voice

services and data delivery using

digital modulation.


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GSM - History

Developed by Group Spciale Mobile (founded 1982) which wasan initiative of CEPT ( Conference of European Post and

Telecommunication)

Aim : to replace the incompatible analog system

Presently the responsibility of GSM standardization resides withspecial 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

Today many providers all over the world use GSM (more than 135

countries in Asia, Africa, Europe, Australia, America)

More than 1300 million subscribers in world and 45 million

subscriber in India.


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GSM Network Architecture


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GSM System Architecture

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)

Authentication Center (AUC)

Equipment Identity Register (EIR)


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contMobile Station (MS)

The Mobile Station is made up of two entities:

1.Mobile Equipment (ME)

2. Subscriber Identity Module (SIM)


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contMobile Station - SIM

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

Encoded network identification details

- Key Ki,Kc and A3,A5 and A8 algorithms

Protected by a password or PIN

Can be moved from phone to phone contains key information toactivate the phone


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contBase Station Subsystem

BSS 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)


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contBase 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


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contBase 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


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contMobile 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 toother network by using HLR/VLR.


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cont Home Location Registers (HLR)

- permanent database about mobile subscribers in a largeservice 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,LocationArea,authentication key


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cont 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 Black List andthe Gray List

- Only one EIR per PLMN


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GSM - Operation

Speech decoding

Channel decoding

De-interleaving

Burst Formatting

De-ciphering

DemodulationModulation

Ciphering

Burst Formatting

Interleaving

Channel Coding

Speech coding

Radio Interface

Speech Speech

13 Kbps

22.8 Kbps

22.8 Kbps

33.6 Kbps

33.6 Kbps

270.83 Kbps


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Core Technologies

2G - Second generation telephone technology is based on. Secondgeneration was launched in Finland in the year 1991.

2G networks are fully digital while their predecessors were

analog.

Three primary benefits

Improved voice quality (less noise)

Longer battery life

Encryption

2.5G

Second and a Half generation telephone technology was thestepping stone between 2G and 3G cellular wireless technology.

It can provide some of the benefits of 3G and can use some of the

existing 2G infrastructure in GSM and CDMA.


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Core Technologies cont

3G Third Generation telephone technology is the superseding

technology to 2G and preceding 4G.

The International Telecommunications Union (ITU) defined the

third generation (3G) of mobile telephony standards IMT-2000 tofacilitate growth, increase bandwidth, and support more diverse

applications.

Service includes wide area wireless voice telephony , video calls,

and broadband wireless data, all in a mobile environment.

It incorporates high speed Internet access.


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Future of 3G

3G evolution (pre-4G)

The standardization of 3G evolution is progressing in both 3GPP and

3GPP2.

The corresponding specifications of 3GPP and 3GPP2 evolutions arenamed as LTE and UMB, respectively. 3G evolution uses partly beyond 3G

technologies to enhance the performance and to make a smooth

migration path.

A 4g network is in the pipe line, capable of speeds of 100Mbit/s whilemoving and 1Gbit/s stationary. This however will take some time.


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Thank you!

Documents

BSNL GSM training presentation