prerak show

8/9/2019 Prerak Show

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Presentation on GSM

Network

RAVI KUMAR

KHANDELWAL

VII SEM

EC-B

PRERAK KUMAR

JOSHI

VII SEM

EC -B


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COMPANY

Nokia SiemensNetworks


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NOKIA SIEMENS

Telecom Service Provisions

GSM

Basic

Internet

GSM Service Provider in INDIA

Basic Service Provide FOR VODAFONE.


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ORGANISATION STRUCTUREPROMOTERS

TECHNICAL PLANNING

IMPLEMENTATION OPERATIONS

OPERATIONS SYSTEM SUPPORT BILLING

IT ACTIVATIONS

MARKETING

CUSTOMER CARESALES

SUPPORT FUNCTIONS HR, ADMIN, ACCOUNTS


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Cellular Communication

A cellular system links Mobile subscribers to

Public Telephone System or to another Mobile

subscribers.

It removes the fixed wiring used in a traditional

telephone installation.

Mobile subscriber is able to move around,

perhaps can travel in a vehicle .


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The CELL

What is a cell ?

A cell is a certain area

that can be reached

with one transceiver

or

A small collection of

transceivers on

different channels at a

single base site.

The hexagonal-shaped communication cells are

artificial & are generated to simplify the planning &

design of a cellular network.

BTS


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Cells


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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.


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GSM - IN CELLULAR TELEPHONY

Each Cell in the Cellular Network consists of

one or more RF carriers.

An RF carrier is a pair of radio frequencies One used in upward direction by MS - Uplink

Other used in downward direction by BTS -

Downlink

The transmit and receive frequencies are

separated by a gap of 45 MHz in GSM of 75 MHz

in DCS.

There are 124 carries in GSM Band. With each


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Uplink-Downlink

Downlink = 935 to 960 MHz

Uplink = 890 to 915 MHz

BTS Tx MS Rx

BTS Rx MS Tx

dl

ul


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SERVICES

It contains two phases. Phase 1 Phase 1 contains the most common services including: Voice telephony International roaming Basic fax/data services (up to 9.6 kbits/s) Call forwarding

Call barring Short Message Service (SMS) Phase 1 also incorporated features such as ciphering and Subscriber Identity Module (SIM) cards.

Phase 1 specifications were then closed and cannot be modified.

Phase 2 Additional features were introduced in GSM phase 2 including: Advice of charge Calling line identification Call waiting Call hold Conference calling Closed user groups Additional data communications capabilities


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GSMSyst r it t r

BSC

BSC

MSC

MS

MS

MS BTS

BTS

BTS

GMSC

PSTNISDNPDN

EIR

UC

HLR

VLR


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GSM System Architecture-I 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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System Architecture

Mobile Station (MS)

The Mobile Station is made up of two

entities:1. Mobile Equipment (ME)

2. Subscriber Identity Module (SIM)


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System Architecture

Mobile Station (MS)Mobile Equipment

Portable,vehicle mounted, hand helddevice

Uniquely identified by an IMEI(International Mobile Equipment Identity)

Voice and data transmission Power level : 0.8W 20 W


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System Architecture

Mobile Station (MS) contd

Subscriber Identity Module (SIM)

Smart card contains the International

Mobile Subscriber Identity (IMSI) Allows user to send and receive calls andreceive other subscribed services

Encoded network identification details- Key Ki,Kc and A3,A5 and A8 algorithms

Protected by a password orPIN Can be moved from phone to phone

contains key information to activate the ph


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SIM

Subscriber Identity Module

The SIM stores

Subscriber Parameters

Personal Data for identifying

Subscriber to the Network.

IMSI,, MSISDN, PIN, PUK, Ki,

(for Kc generation)

Space reserved for TMSI & LAI

--------

------

--------

------

Small SIM

Full Size SIM Card

--------

------

--------

------


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System Architecture

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)


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A BTS Cabinet

OUTER VIEWINNER VIEWNETC

OMP


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System Architecture

Base Station Subsystem (BSS)-Base Transceiver Station (BTS):

Encodes,encrypts,multiplexes,modulatesand feeds the RF signals to the antenna.

Communicates with Mobile station and

BSC

Consists of Transceivers (TRX) units


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System Architecture

Base Station Subsystem (BSS)

Base Station Controller (BSC):

Manages Radio resources forBTS

Assigns Frequency and time slots for allMSs in its area

Handles call set up

Transcoding and rate adaptation

functionality Handover for each MS

It communicates with MSC and BTS


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System Architecture

NetworkSwitching 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- InterBSS and inter MSC call handoff

MSC does gateway function while its customerroams to other network by using HLR/VLR.


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MOBILE SWITCHING CENTRE

NETC

OMP


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System Architecture

Network Switching Subsystem Home Location Registers (HLR)

- Permanent database about mobile subscribers ina large service area(generally one per GSMnetwork operator)

- Database containsIMSI,MSISDN,prepaid/postpaid, roamingrestrictions,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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System Architecture

Network Switching Subsystem

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 MobileEquipment Identity)

- Made up of three sub-classes: The WhiteList, The Black List and the Gray List

- Only one EIR perPLMN


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GSM Specifications-1

RF Spectrum

GSM 900Mobile to BTS (uplink): 890-915 MHzBTS to Mobile(downlink):935-960 MHzBandwidth : 2* 25 MHz

GSM 1800

Mobile to BTS (uplink): 1710-1785 MHzBTS to Mobile(downlink) 1805-1880 MHzBandwidth : 2* 75 MHz


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GSM Specification-II

Carrier Separation : 200 KHz

Duplex Distance : 45 MHz

No. of RF carriers : 124 Access Method : TDMA/FDMA

Modulation Method : GMSK

Modulation data rate : 270.833 Kbps


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Call Routing

Call Originating from MS

Call termination to MS


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Outgoing Call1. MS sends dialed number to

BSS2. BSS sends dialed number to

MSC3,4 MSC checks VLR if MS is

allowed the requested

service. If so, MSC asks BSSto allocate resources for call.

5 MSC routes the call to GMSC6 GMSC routes the call to

local exchange of called user

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

tone is routed from calleduser to MS viaGMSC,MSC,BSS


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Incoming Call

1. Calling a GSM subscribers2. Forwarding call to GMSC3. Signal Setup to HLR4. 5. Request MSRN from VLR

6. Forward responsible MSCto GMSC

7. Forward Call to currentMSC

8. 9. Get current status of MS

10.11. Paging of MS12.13. MS answers14.15. Security checks16.17. Set up connection


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Handovers

*Between 1 and 2 Inter

BTS / Intra BSC

*Between 1 and 3 Inter

BSC/ Intra MSC

*B

etween 1 and 4

InterMSC


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Characteristics of GSM Standard

Fully digital system using 900,1800 MHz frequencyband.

TDMA over radio carriers(200 KHz carrier spacing.

8 full rate or 16 half rate TDMA channels per carrier.

User/terminal authentication for fraud control. Encryption of speech and data transmission over the

radio path.

Full international roaming capability.

Low speed data services (up to 9.6 Kb/s).

Compatibility with ISDN.

Support of Short Message Service (SMS).


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Japanese

Hebrew

ThankYou

English

MerciFrench

Russian

DankeGerman

GrazieItalian

GraciasSpanish

ObrigadoPortuguese

Arabic

Simplified Chinese

Traditional Chinese

Tamil

Thai

Korean


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