mobile commn_summer trg

R.T.T.C. HYDERABAD

GSMGlobal System for

Mobile Communications

R.T.T.C. HYDERABAD 2

Contents

• Objective• GSM Principles• Cellular Technology• GSM Network• Call Processing• Handoffs• GPRS• EDGE


MOBILE COMMUNICATION

• Any time Anywhere• Mobility & Roaming • High capacity & subs. density• Efficient use of radio spectrum• Seamless Network Architecture• Low cost• Flexibility• Innovative Services• Standard Interfaces


Public Land Mobile Network

• INDIA has adopted GSM standard for PLMN.

• Digital Cellular System.• Operates at 900 MHz.• International Roaming facility.• Power class 0.8 to 20W.• Cell Radius upto 35 Kms.• Maximum mobility speed 250 Km/hr.


GSM900 :up: 890~915MHz down: 935~960MHzduplex interval: 45MHzbandwidth: 25MHz ，frequency interval:

200KHzGSM1800 :up: 1710-1785MHz down: 1805-1880MHzduplex interval: 95MHz ，working bandwidth: 75MHz ，frequency interval: 200KHz

EGSM900 :

up: 880~890MHz

down: 925~935MHz

duplex interval: 45MHz

bandwidth: 10MHz ，frequency interval: 200KHz

GSM1900MHz:up:1850~1910MHzdown:1930~1990MHzduplex interval: 80MHz ，working bandwidth: 60MHz ，frequency interval: 200KHz

Allocated GSM Frequency Bands


BANDWIDTH MANAGEMENT TECHNIQUES

• FDMA • TDMA • Cellular Technology & Frequency Re-use Scheme


FDMA

• Frequency Division Multiple Access Scheme

• Uplink Frequency Band = (890 – 915) MHz• Downlink Frequency Band = (935 – 960)

MHz

• Absolute Radio Freq Carrier Number (ARFCN)

• Bandwidth = 915 – 890 or 960 – 935 = 25 MHz


GSM-FDMA

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 960915

200 kHz


TDMA

• Time Division Multiple Access Scheme• One Radio Frequency = Eight Time

Slots• One TDMA Frame = Eight Time Slots• One Time Slot = One Physical Channel• One Time Slot Duration = 0.577 m.sec


GSM-TDMA

8765

43

21

8765

43

21

45 MHz

Frequency

F2’F1’(Cell transmit)

F2F1(Cell Rx)

Amplitude

Typical TDMA/ FDMA frame structure


Cellular Technology

• Cell • Site

• Cluster


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). Types of Cells

•OMNI CELLS•SECTOR CELLS - Two Sector Cells

- Three Sector Cells


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


A CLUSTER OF CELLS

4

5

6

7

2

3

1 1 2 3 4 5 6 7

GIVEN FREQ. RESOURCE

CELLULAR MOBILE CONCEPTS


:Interference caused by another cell/mobile using the same frequency

D

R

Co Chl Interference is a Function of “Q”the re-use ratio:

Q =D / R

Lower Q Increased Co-Chl Interference

Higher Q Reduced Co-Chl Interference

CO-CHL INTERFERENCE


CLASSIFICATION OF CELLS

• MICRO CELL• MACRO CELL• UMBRELLA CELL


GSM subsystems

1. Network Subsystem includes the equipments and functions related to end-to-end call.

2. Radio Subsystem includes the equipments and functions related to the management of the connections on the radio path.

3. Operations and Maintenance subsystem includes the operation and maintenance of GSM equipment for the radio and network interface.

18R.T.T.C. HYDERABAD

BTS

MSC VLR

HLR

PSTNISDN

DataNetworks

Air interface

OSS

BTS

BTS

MSC VLR

BSCBSC

1 MSC=16 BSC, 1 BSC=1024 TRU

A Interface

A-bis interface

BSC:BASE STATION CONTROLLER, BTS: BASE TRANSRECEIVER STATION, OSS: OPERATION AND SUPPORT SUBSYSTEM.ss

Network Architecture


GSM Network Structure

• GSM Service Area: Total area served by the combination of all member countries where a mobile can be served.

• PLMN Service Area:It is one N/W area. • MSC Service Area:There can many MSC/VLR

in one PLMN area.It is one Mobile Exch. Area.

• Location Area: 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.

• Cells


V

MSC

MSC

MSC

MSC

VLR

VLRVLR

I II

IVIII

I

GSM PLMN Service Area


MSCVLRLA1

LA2LA3

LA6LA4

LA5

GSM MSC Service Area


MSC

VLR

LA1

LA2

LA3

LA6LA4

LA5

C1C2 C3

C6 C5C4

C=CELL

GSM Cells


GSM--Relation between areas in GSM

Location AreaCellArea served by a BTS

Location AreaMSC Service AreaPLMN Service AreaGSM Service Area


Call Processing


• SETUP PHASE

• RINGING PHASE

•CONVERSATION PHASE

•RELEASE PHASE

Mobile Originated Call- MO Call


- REQUEST FOR SERVICE ( CHANNEL ) BY MS

- CM SERVICE REQUEST

- AUTHENTICATION

- CIPHERING

- SETUP MESSAGE

- EQUIPMENT VALIDATION ( EIR CHECK )

- VALIDATION AT VLR

- ASSIGNMENT

Mobile To Land Call Set-up Scenario

• SETUP PHASE


Mobile To Land Call Set-up Scenario

MSC/VLR

Call Setup message

Is the requested basic service

provisioned for the subscriber ?

Yes

No

Release Complete

message to MS

Preliminary Digit Analysis

Is the number of digits less than the

minimum expected?

Yes

Release Complete

message to MS

No1. Check of ODB( BAOC/BOIC/ BOIC Ex HC )

2. Subscriber call barring checks(BAOC/BOIC etc. )

ASSIGNM ENT


• Routing Analysis

• Paging

• Authentication

• Call-Setup

• Ciphering

• Call Release

Mobile Terminating - MT Call


Handover

• Hard Handover – Break before make• Soft Handover – make before break• Softer Handover


Handovers


GSM Evolution

GPRS200 KHz carrier115 Kbps peak data rates

EDGE200 KHz carrierData rates up to 384 Kbps8-PSK modulationHigher symbol rate

UMTS5 MHz carrier2 Mbps peak data ratesNew IMT-2000 2 GHz spectrum

GSM200 KHz carrier8 full-rate time slots16 half-rate time slots

GSM GPRS EDGE UMTS

3G2.5G2G

HSCSD

HSCSDCircuit-switched data64 Kbps peak data rates


MAIN ADVANTAGES FOR OPERATORS

• More Revenue :

By providing more than a mobile connection.

Also operator can charge on the basis of type and amount of content accessed.

• Huge Potential Market for Data Sevices :

Mobile Phone and Internet, both are fastest growing technologies and GPRS is the merger of two.

• Fast Roll-out and Continuous Network Expansion :

GPRS is an integral part of GSM.

• GPRS uses excess voice capacity for data :

GPRS Packets are transmitted in short, free periods between busy hour calls.


2.5G-GPRS Vs 2G-GSM

2.5G – GPRS (GSM Advanced)

2G-GSM

SUPPORTS BOTH CKT. SWITCHED as well as packet switched service.

Only circuit switched.

MS Utilizes Automatic retransmission (ARQ) at data link layer to re-transmit error frames.

No re-transmission is provided.

Multiple time slots can be allotted to a single user

Single time slot per user.

One time slot can be allotted to several users.

Single time slot per user.

Charging/ billing more complex (Volume based, Q.O.S. based)

Simple time-based billing.


GPRS Network

HLR

Air (Um)

Gb

Gs Gr Gf

Gn

Gn Inter-PLMN

GPRS Backbone

Gp

External packet network

Gi

SGSN

EIR

BSC

MSC/ VLR

SMS- GMSC

Gd

GGSN

GGSN

Signalling and data

Signalling


EDGE Enhanced Data rates for GSM Evolution

GPRS = General Packet Radio System

EGPRS = GPRS + EDGE modulation


* Communications- E-mail, fax, intranet/ internet access.

* Value added services - Information services, games, e-commerce.

* Location-based Navigation, traffic conditions, applications - airline/rail schedule, location finder.

* Vertical applications - Freight delivery, fleet management, sales-force automation

* Location sensitive A user nearing a cinema hall or Advertising - a restaurant receives flashes of advertisement

TYPICAL GPRS SERVICES


Mobile VAS

VAS categoriesVAS categories

EntertainmentEntertainment InformationInformation mCommercemCommerce

Entertainment VAS is

designed for mass

appeal and extensive

usage.

These provide

entertainment for leisure

time usage

E.g. Jokes, Bollywood

ringtones, games, etc.

Information VAS provides useful information to the end user

User interest comes in from the personal component of the content

E.g. News alerts, travel information, ticket information, etc.

mCommerce allow the use to conduct a transaction using the mobile phone.

Currently in a nascent stage

E.g. banking applications from Barclays, ICICI bank and payment platform from paymate, obopay, etc.


VALUE ADDED SERVICES

• Very high speed downloads

• IPTV

• Quicker MMS

• Video call

• Streaming Applications – Youtube, etc.

• Corporate Intranet connections

• Vertical corporate applications – Video

Conference, Remote presentations


MMS• Multimedia Messaging Service (MMS)

• Message of Text, Sound, Image, Video etc• Graphs, Tables, Diagram , Maps etc

Phone 2 Phone

Phone 2 e-mail

e-mail 2 Phone


Mobile TV allows the user to view TV channels on the mobile

Mobile TV allows the user to view TV channels on the mobile


Full movie /music download

Live news & sport updates

Interactive games

Video streaming

Wallpapers and

Tone downloads

Full movie /music download

Live news & sport updates

Interactive games

Video streaming

Wallpapers and

Tone downloads

The content services include the following:The content services include the following:


Products & Services 2

BSNL offers Live IPTV as well as a wide range of exciting VAS

BSNL Live WAP Portal Video-on-Demand Full movie downloads

Full-track music downloads Multiplayer gaming

Live TV

3G-Training deck-v21.ppt

42


This has happened:This has happened:

This is happening now:This is happening now:


Access devices like a portable laptop or a mobile handset are typically used.

Access devices like a portable laptop or a mobile handset are typically used.

Mobile Broadband signifies Mobile Broadband signifies

High speed Wireless access High speed Wireless access

3G gives the user the flexibility to access high speed internet any time anywhere.

3G gives the user the flexibility to access high speed internet any time anywhere.


Video Call

With the deployment of 3G,Video call

service will put BSNL on clear cut

advantageous positionwith respect to it’s

competitors

With the deployment of 3G,Video call

service will put BSNL on clear cut

advantageous positionwith respect to it’s

competitors


Video Call

A girl in a city looking and talking to her grandmother ,living in a rural area, through 3G Phone

A girl in a city looking and talking to her grandmother ,living in a rural area, through 3G Phone


Thank You

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