3928235 GSM Overview

7/29/2019 3928235 GSM Overview

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REG. NO.- U05EC005

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OBJECTIVES

Describe the Cellular Concept

Explain the GSM Access Network

Explain the GSM Core Network

Explain the GPRS Core Network

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Communication - Mobile

TelephoneExchange

Subscriber

Line(2W)

Inter-Exchange

Junction

Mobile SwitchingCentre (MSC)

BSC BTS MS

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CELLULAR MOBILE CONCEPTS

WHAT IS A CELL ?

• A base station (transmitter) having a number of

RF channels is called a cell

• Each cell covers a a limited number of mobile

subscribers within the cell boundaries

( Coverage area)

• Typical Cell Radius Aprrox = 30 Km(Start up), 1 KM (Mature)

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VoiceChannels

Orcontrol

channels

Lines to

BSC

MS

A RADIO CELL

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Fundamental problems

• Radio range, or coverage

• No. of channels, or voice circuits

• Full, seamless service coverage

• Large no. of subscribers in the range

of millions

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FERQUENCY SCARCITY PROBLEM

Tel

Ex.

WIRED NETWORK

100,000 50 Khz = 5 Ghz (NOT POSSIBLE)

Hence Individual RF Loop is not extended

But a Common group of channels is shared

CELLULAR MOBILE CONCEPTS

BW for Telephony speech:

3KHz increases to 25 KHz with FM for Radio Trans.

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GSM Specifications

Carrier Separation - 200 kHz

No. of RF Carriers - 124

Access Method - TDMA/FDMA

Modulation Method - GMSK

Transmission Rate - 270.833 Kbps

Speech Coding - Full rate 13 Kbps

Half rate 6.5 Kbps

Duplex Distance - 45 MHz

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GSM FDMA

(Frequency Division Multiple Access

25 MHz 25 MHz

Mobile to Base

0 1 2

890.2 890.4 890.6 (MHz)

Base to Mobile

0 1 2

935.2 935.4 935.6

200 kHz45MHz

Channel layout and frequency bands of operation

890 935 960 915

200 kHz

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GSM TDMA

(Time Division Multiple Access)

87

65

43

21

87

65

43

21

45 MHz

Frequency

F2’ F1’ (Cell transmit)

F2 F1(Cell Rx)

Amplitude

Typical TDMA/ FDMA frame structure

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FDMA/TDMA Scheme

BP1

BP2

BP3

BP4

BP5

BP6

BP7

BP8

BP1

BP2

TIME

890.0 890.2

890.4 890.6

890.8 891.0

891.2 915.8

FREQ

MHz

BURST F

R

A

M

E

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LOGICAL CHANNELS• USER INFORMATION( TRAFFIC)

• SIGNALLING INFORMATION (CONTROL)

GSM RF CHANNELS

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OPERATIONAL CONCEPTS

• Subscribers are not allocated dedicated channels

• TCH Allocated to users only when needed

• Hence IDLE MODE & DEDICATED MODE

• DEDICATED MODE

-- When a full Bi -directional P to P CHL

has been allocated during an established call

• IDLE MODE MODE

-- When MS is powered on (active)

without being in dedicated mode

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Network Architecture

B

TS

MSC VLR

HLR

PSTNISDN

Data

Networks

Air interface

OSS

BTS

BTS

MSC VLR

BSCBSC

1 MSC=16 BSC

1 BSC=1024 TRU

A Interface

A-bis interface

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GSM Network Structure

• GSM Service Area: Total area served by thecombination of all member countries where a mobile canbe served.

• PLMN Service Area: It is one N/W area.

• MSC Service Area: There can many MSC/VLR in onePLMN area.It is one Mobile Exch. Area.

• GMSC: All I/C calls for PLMN N/W will be routedthrough GMSC. In a GSM/PLMN N/W all mobileterminated calls will be routed to a Gateway MSC. Call

connections between PLMNs , or to fixed N/Ws must berouted to a GMSC.The GMSC contains the Inter workingfunctions to make these connections.

• Location Area

• Cells

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LOCATION AREA : There are several LA in a MSC/VLR

combination. A LA is a part of the MSC/VLR service area in

which a MS may move freely without updating location

information to the MSC/VLR exchange that control the LA.

Within a LA a paging message is broadcast in order to findthe called mobile subs. LA can be identified by system using

the LAI.

CELL : A cell is an identity served by one BTS. The MS

distinguishes between cells using the BASE STATIONIDENTIFICATION CODE(BSIC) that the cell site broadcast

over the air.

GSM Network Structure

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MSC/VLR

MSC/VLR

MSC/VLR

MSC/VLR

II

I

IIIIV

GSM

PLMN Service Area

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MSC/VLR

LA 1 LA 2

LA 6

LA 3

LA 4

LA 5

GSM

MSC Service Area

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MSC/VLR

LA 1 LA 2

LA 6

LA 3

LA 4

LA 5

C1

C5C4

C7

C2

C3

C6

GSM

Cells

C = Cell

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GSM

Relation between areas in GSM

Location AreaCell

Area served by a BTS

Location Area

MSC Service AreaPLMN Service Area

GSM Service Area

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GSM

Functions of Mobile Station

• Voice and data transmission

• Frequency and time synchronization

• Monitoring of power and signal quality of

the surrounding cells

• Provision of location updates even during

inactive state

• Equalization of multi path distortions

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GSM

Mobile Station

• Portable, vehicle mounted, hand held

• MS identified by unique IMEI(International Mobile Equipment

Identity)

• Shall display at least last ten received, dialled andmissed calls

• Minimum talk time of 1hr 30 min. and standby

time of 80 hrs

• 160 characters long SMS

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GSM

Mobile Identification Numbers

IMEI

MSISDN

IMSI

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GSM

IMSI• International mobile subscriber’s

Identity

• The IMSI is an unique identity which isused internationally and used within thenetwork to identify the mobile subscribers.

• The IMSI is stored on the subscriberidentity module (SIM), the HLR, VLR andAC database.

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RSS

n BTS n BTS

BSC

BSC

BSC

MSC/VLR

RADIO SUB SYSTEM (RSS)

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GSM

FUNCTION OF BTS -I

• Encodes, encrypts, multiplexes, modulates and

feeds the RF signals to the antenna

• Transcoding and rate adaption Functionality• Time and frequency synchronisation signals

transmission.

• 11 power classes from .01 watts to 320 watts

GSM

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GSM

FUNCTION OF BTS -II

• Frequency hopping

• Random access detection

• Uplink radio channel measurements

• BTS mainly consists of a set of transceivers

(TRX).

GSM

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GSM

FUNCTIONS OF BSC-I

• It is connected to BTS and offloads MSC

• Radio resource management

• Inter-cell handover

• Reallocation of frequencies

• Power control

GSM

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GSM

FUNCTIONS OF BSC-II

• Time delay measurement of the received signals

from MS with respect to BTS clock.

• Performs traffic concentration to reduce the

number of lines from BSC to MSC.

GSM

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GSM

MSC-BSS Configurations

BTSBTS

BTS

A-bis

BSC

BSS

Configuration -6 Multi - cell site =multi--BTS site

Many singlecell sites

BSS

MSC

BTS

AA

A

Single - cell siteConfiguration -1

Multi - cell site (sector CellsConfiguration -5

MCC: Mobile Switching Centre

BSS: Base Station System

BSC: Base Station Controller

BTS: Base Transceiver Station

A-bis

BTS BTS

BTS

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GSM MSC ( MOBILE SWITCHING CENTRE)

Manages communication between GSM & other

network

Call setup functions, basic switching are doneMSC takes into account the RR allocation in

addition to normal exchange functions

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

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GSM

MSC Functions - I

Paging, specifically call handling

Location updation

Handover management

Billing for all subscribers based in its area

Reallocation of frequencies to BTSs in its area

to meet heavy demands

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GSM

MSC Functions - II

Echo canceller operation control

Signaling interface to databases like HLR,

VLR. Gateway to SMS between SMS centers and

subscribers

Handle interworking function while

working as GMSC

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GSM

VISITOR LOCATION REGISTER (VLR)-I

It controls those mobiles roaming in its area.

VLR reduces the number of queries to HLR

One VLR may be incharge of one or more LA.

VLR is updated by HLR on entry of MS its area.

VLR assigns TMSI which keeps on changing.

IMSI detach and attach operation

GSM

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GSM

Data in VLR

IMSI & TMSI

MSISDN

MSRN.Location Area

Supplementary service parameters

MS category

Authentication Key

GSM

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GSM

Home Location Register(HLR)-I

• Reference store for subscriber’s parameters,numbers, authentication & Encryption values.

• Current subscriber status and associated VLR.

• Both VLR and HLR can be implemented inthe same equipment in an MSC.

• one PLMN may contain one or several HLR.

GSM

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GSM

Home Location Register(HLR)-II

Data stored is changed only by man-machine.

IMSI, MS-ISDN number.

Category of MS ( whether pay phone or not )

Roaming restriction ( allowed or not ).

Supplementary services like call forwarding

Permanent data in HLR

GSM

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Temporary data in HLRThe data changes from call to call & is

dynamicMSRN

RAND /SRES and Kc

VLR address, MSC address.

Messages waiting data used for SMS

GSM

Home Location Register(HLR)-II

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GSM SERVICES

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GSM Services

Services are defined as anything the end userexplicitly sees as worth paying for.

The primary objective of a mobile telephonysystem is to allow mobile subscribers tocommunicate effectively.

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SERVICE CATEGORIES

Main type of telecommunication services:

☻ Basic services:Available to all subscribers to a mobile network.

e.g. voice telephone calls.

☻ Supplementary services:Additional services that are available by subscription

only.

e.g. Call forwarding.

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Basic Telecommunication Services

Two main categories:

Teleservices

Bearer Services

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Teleservices

Teleservice allows the subscriber to communicate

(usually via voice, fax, data or SMS) with another

subscriber.

It is a complete system including necessary terminalequipment.

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Bearer services

It transports speech and data as digital information

within the network between user interfaces.

e.g.- a bearer service associated with the speech

telephony teleservice is the timeslot assigned to acall on a TDMA frame over the air interface.

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TELESERVICES

Emergency calls

The emergency call function enables a subscriberto make an emergency call by pressing a

predefined button or by using the emergency

number. (like 112 , 911).

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SMS Cell Broadcast (SMSCB)

A text message with a maximum length of

93 characters can be broadcast to allmobiles within a certain geographic area.

traffic congestion warnings

accident reports,weather announcements and

advertisements.

TELESERVICES

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Calling line identification services:

These cover both the presentation and restriction

of the calling line identity.

The presentation part of the service supplies the

called party with the ISDN or MSISDN number of

the calling party. The restriction service enables

calling parties to restrict the presentation of theirnumber on the MSs of called parties

SUPPLEMENTARY SERVICES

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Value Added Services

Mobile Messaging

Mobile internet

Mobile intelligent Network Services

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Some Applications

•Internet e.g. WAP

•E-mail

•Messaging Services e.g. MMS•Telemetery

•M-Commerce

•Location Based Service•Games

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Mobile

internet

Sports MTV

Jokes

Grocery

Prepaid,

messaging

GamblingCompany

data

Customer

data

Banking

data

Financial/

Stock news

Other

news

Young

people

Middle aged

Financial

community/trader

Traveling sales/-

business man

Anybody else

Wireless World - there’s something for everyone

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Unified Messaging

Mobile Positioning

Multimedia Messaging

Mobile Banking

Bluetooth:

Location based

Mobile E-mail:

Corporate Lan Access

Wireless World

bring in New Services Mobile Trading

Mobile Shopping

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Mobile Applications

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Mobile Messaging

SMS

EMS

MMS

Instant Messaging

Streaming

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Short Message Services (SMS)The service allows simple text message consisting of a

maximum of 160 alphanumeric characters to be sent to or

from an MS.

If the MS is switched off, or has left the coverage area, the

message is stores in a Short Message Service Center

(SMS-C).

When the mobile is switched on again or has re-entered the

network coverage area, the subscriber is informed that

there is a message.

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Enhanced Messaging System (EMS)

• EMS can support relatively simple pictures,sounds and

animation.

• EMS messages that are sent to devices that do not support

it will be displayed as SMS transmissions.

• It is a 3GPP standard.

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• MMS means a multimedia presentation which consists

of music, voice, image, text, video and graphics all

synchronized across a common timeline.

• “Synchronized Power Point Presentations”.

MULTIMEDIA MESSAGE SERVICE

(MMS)

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• MMS-enabled mobile phones enable subscribers to

compose and send messages with one or more multimedia

parts. Mobile phones with built-in or attached cameras, orwith built-in MP3 players are very likely to also have an

MMS messaging client -- a software program that

interacts with the mobile subscriber to compose, address,

send, receive, and view MMS messages.

MULTIMEDIA MESSAGE SERVICE

(MMS)

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Multimedia Messaging - Any combination

of media types

Videoand

Audio

Images

Graphics

Music

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rich content to encourage usageCartoons, Dating, Pop stars, Sports stars, Pets,

Special occasions, Hobbies, Sports results, TV programmes,News, Weather, Holidays, Timetables, Family...

http://www.bradpittfan.com/pics/magazine/premiere/mpr018b.jpg

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SMS MMS

Text Based Messagingrich content including text, graphic,

photos etc.

Proprietary Standard Based upon 3 GPP & WAP standards.

Store & Forward system Store & Forward system

Uses signaling links MMS uses main data channel.

SMS & MMS

** 3rd Generation Partnership Project (3GPP) **

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Instant Messaging

It enables to communicate with another

individual in real time, analogous to a

telephone conversation but using text based

communication instead of voice-based

communication.

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Streaming• It enables real time or on demand

distribution of audio, video and multimedia

on the internet.

• It is simultaneous transfer of digital media

(video,voice and data) so that it is received as

a continuous real-time stream.

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Movies

Video-clips

Photos

Pictures

Applications Evolution – user perspective

SMS

EMS

MMSText

Streaming

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Where do we fit in ???

• Ringtones and Images over SMS, EMS and MMS

• Games over SMS for single, multi player and as a team

• Gaming servers handling SMS, WAP and Java games

• MMS applications for Imaging and Melodies

• Java applications on handsets

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Content & Application

Fun: Cartoon of the day, Tarot cards, Cocktail recipes, Alcometer, Daily Horoscope,Personality Test,

Games: Hangman, Puzzles & Riddles, Cute’n’clever, Lifestyler, Friends PopStar, PopQuiz, Jewel & Rubin, Amour

Photo & Film: PhotoGallery, Mobile Greeting Card, My SoapOpera,

Chat & date: Mobile Chat, Love Horoscope, Love Matcher

Music: Karaoke, Fan Packages, Hit Lists, Music News

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The Greeting Card solution:

• Send Messages to your friends, familyand loved ones:- Via the web to the mobile phone

• Ease of use – self instructing -Drag ‘n’ drop

• Animations, Sounds, Pictures & Text

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MESSAGING

TYPE

STREAMING

INSTANT

MESSAGING

CONTENT

CARRIED

REAL TIME DISTRIBUTION OF AUDIO, VIDEO AND MULTIMEDIA

REAL TIME TEXT BASED COMMUNICATION

MMS PICTURES, SOUNDS AND ANIMATIONS

EMS RELATIVELY SIMPLE PICTURES, SOUNDS AND ANIMATIONS

SMSSIMPLE TEXT

WIRELESS MESSAGING LADDER

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Location Based Applications

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Location Based Services

Positioning application

Where am I

Yellow Pages

Tracking

Fleet management

Brand Finder

Geo Coding, Content,

Application Integration

Positioning methods:

– Cell/Sector , Time of Arrival

-- Network Based AGPS – Terminal Based EOTD

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• Stickiness : Daily traffic info. pushed during

rush hours via SMS/MMS

• Most people need to know the currenttraffic sitution on their route.

• Hosting: Operator / ISP

• WAP/Web/MMS/SMS: yes/yes/yes/yes

• Devices supported: - All devices

• Commerically used worldwide

This service both collects and distributes traffic information. Traffic informationis very important need for city dwellers. Systems can estimate trafficinformation by sampling mobiles in automobiles on freeways anonymously todetermine average velocity of vehicles. If this is not possible in locataion morestatic information can be collected from city authorities. All this information ismapped and sent to mobile users who request it.

APPLICATION OVERVIEW

Traffic Information

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Positioning based

information,advertisements...

Telecom & backhand ITinfrastructure makes it

possible!

All Trademarks and Registered Trademarks are of respective holders

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Operations

• Dispatchoperationsinterconnected: – Taxi – Field services – Parcel services

• Emergencyservices

Automation

• Vending

machines

• Lotterymachines

• Automatic ticket

machines

M2M –

Services

• Alarm &

supervision

• Point of sales

• Telemetry

• Financial

services

M2M –

Vehicle

• Vehicle tracking

• Electronic maps

• Traffic

telematics

• Car tolls

Vertical applications

Its all about Imagination……...

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Machine to Machine communication (M2M)

Some key technologies for M2M

• Bluetooth

• GSM/GPRS

• GSM/SMS

• WiFi

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I don’t need wires

to connect anymore

Help! I’m almost out of coke bottles…….

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age/status?

attitude?

culture?

interests?

financial situation?

location?

time?

behaviour/mood?

Who are your customers?

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Thanks

Documents

3928235 GSM Overview