Mobile Communication System - Electrical Engineering - Lecture Slides, Slides of Electrical Engineering

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LECTURE

ON

MOBILE

COMMUNICATION

SYSTEMS

Terminologies

Base Station: A fixed station in a mobile radiosystem used for radio communication with mobilestations.M.S.C

:Switching

centre

which

co-ordinates

the

routing

of

calls

and

connects

the

cellular

base

stations and the mobiles to the P.S.T.NMIN: Mobile identification numberE.S.N: Electronic Serial NumberS.C.M: Station class marksSIM: Subscriber Identity Module

ADVANCED MOBILE PHONE SYSTEM

(AMPS)

•^

AMPS is known as the first generation (1G)analog commercial cellular systems. It is one ofthe

earliest

cellular

systems

or

mobile

phone

system standard. It introduced in early 1980s.

-^

It is based on Analog modulation.

-^

This allowed a larger number of phones to besupported over a geographical area.

-^

It is the earliest radio standard in North America

GSM(Global System For Mobile)

-^

It Is a second generation technology.

-^

GSM was originally developed to serve as thepan-european cellular service.

-^

By

the

end

of

several

non-european

countries in Asia, Australia had adopted GSM

-^

By

there

are

million

GSM

subscribers around the world

Architecture Of GSM

Base Station Controller

Controls:

Wireless link distribution between MS and BTS

Communication connection and disconnection

MS location, handover and paging

Voice encoding, trans encoding (TC) rate, adaptation,

The operation and maintenance functions of BSS.

Mobile Service Switching Center ( MSC ) •^

holds all the switching functions and manages thenecessary

radio

resources,

like

updating

the

location

registration

carrying

out

the

inter-BSC

and

inter-MSC tenderInter-working with other networks (IWF).

Home Location Register( HLR ) Manages

the

mobile

subscribers

database

subscriber information, part of the mobile locationinformation,

3

identities

essential

i.e

the

International

Mobile

subscriber

Identity

,^

the

Mobile station ISDN Number ,the VLR address.

AUC/EIR Providing the authentication key used forauthorizing the subscriber access to the associatedGSM.

-^

Equipment Identity Register(s) (EIR)

-^

Handling Mobile Station Equipment Identity

OMC(Operation Maintenance Centre) •

Maintains all telecommunication hardware andnetwork operations with a particular market

-^

Manages all charging and billing procedures

-^

Manages all mobile equipments in the system

-^

The interface between BSC and MSC is calledA interface and interface between BTS andBSC is called Abis interface

•^

A interface uses an SS7 Protocol called thesignaling correction control part(SCCP) Whichsupports

communication

between

MSC

and

BSS.

•^

Each

subscriber

in

the

GSM

network

is

provided

with

a

IMSI(INTERNATIONAL

MOBILE

SUBSCRIBER

IDENTITY).this

number acts as a identity for home user

• There is near and far problem in CDMA which

is removed by RSSI( Radio signal strengthindicator)Features of CDMA

-^

With

the

use

of

more

numbers

of

Users

efficiency decreases

because more noise is

increases •Multiple fading is removed by using the rake

receiver

•The channels data rate is very high in CDMA

system •Provide soft Hand off•Self Jamming is a Problem in CDMA•Privacy•Grace Degradation

•^

the code received at the output if user a isconsidered as:

-^

•^

The other code words are not selected an theresum is not 6 or less than 6, may be zero.

-^

The given codeword with data is decoded.

G.P.R.S(General Packet Radio Service )^ •

GPRS

facilitates

instant

connections

and

high

immediacy whereby information can be sent orreceived immediately. There are 3 classes of GPRS: •

Class A

:^

Can be connected to GPRS service

and GSM service (voice, SMS), using both at thesame time.

Class B

: an be connected to GPRS service and

GSM service (voice, SMS), but using only one orthe other at a given time.

Class C

: Are connected to either GPRS service

or GSM service (voice, SMS). Must be switchedmanually between one or the other service.