principle of mc.ppt

8/14/2019 Principle Of MC.ppt

1/34

1

AITTM

B.TECH(E&T), SEVENTH SEMESTER

Course on Cellular Communication

Topic: Principle Of Mobile Communication


2/34

2

Evolution of GSM

GSM is offering continuous improvement andmore services.

In 1995 the Phase2recommendations were

frozen.The GSM 900 and GSM 1800specifications were merged and additionalsupplementary services were defined,theshort message services was improved andimprovement in radio access and SIM cardswere introduced.

GSM continuous evolve at full speed.

The number of improvements so large that

together they are called Phase2++ features.


3/34

3

In 1982CEPT initiated a new cellular system.

* For roaming frequencies are in the band of900 MHz.

1987Memorandum of understanding (MoU).

Allocation of frequencies:-890-915MHz uplink &935-960 MHz downlink

1988- European Telecommunication Standard

Institute (ETSI)was created.

1991- First official call in the world with GSM on

1stJuly.


4/34

4

1992- Worlds first GSM network launched in

Finland. The first roaming agreement was made.

By December there were 13 networks operating in

7 areas. Australian operators were the first non-

European signatories of the GSM MoU.New frequency allocation for GSM 1800 (DCS

1800)- 1710-1785 MHz (uplink) & 1805-1880

MHz (downlink).

1993- GSM demonstrated for first time in Africa

at Telkom and there was 32 GSM network

operating in 18 areas.


5/34

5

1994 - The first GSM network in Africa was

launched in South Africa.

1995 -There were 117 GSM networks. Fax,

data, and SMS roaming was

implemented.

* The GSM phase2 standardization was

completed, forGSM 1900 (PCS1900).

1996- There were 120 networks operating.

* The 8K SIM was launched in

addition to prepaid GSM SIM cards.


6/34

6

1998 - HSCSD (High Speed Circuit Switched Data) trials

in Singapore.

1999The first mobile data call using GPRS(GeneralPacket Radio Service)in a live network was made.

LBS is combined with GPS(Global Positioning System), so

that subscriber can determine his geographical locationextremely accurately.

The 3G mobile communications system UMTS was

specified which is based on the GSM standards to allow asmooth evolution from the 2nd generation to the 3rd

generation.this ought to guarantee an investment protection

for GSM operators.


7/34

7

2000- The first GPRS network is launched.

2001- The Multimedia Messaging Service (MMS)

was standardized. GSM 700 supported; UL: 747

762 MHz and DL: 777792 MHz.

2002 UMTS/ GSM Rel.5 standardized (IMS) wasstandardized for GSM/GPRS and UMTS.

Smart phones are under development for GSM/GPRS

and UMTS to allow a wide range of mobile service,such as mobile Internet, mobile gambling, enhanced

LDAs, video messaging, agonistic services, etc.


8/34

8

2003- First commercial starts of UMTS network

operators in Europe.

2004More than one billion people are now

using GSM mobile phones.

More than 200 countries and territories has

adopted GSM and it has become a truly global

standard for mobile communications.


9/34

9

SUMMARY OF GSM BAND

U / L D / L B/W D/D

GSM90 890-915 MHz 935-960 MHz 25 MHz 45MHz

GSM-1800 (DCS-1800) 1710-1785 MHz 1805-1850 MHz 75 MHz 95MHz

GSM-850 (Support) 824-849 MHz 869-894 MHz 25 MHz 45MHz

GSM-700 (MMS) 747-762 MHz 777-792 MHz 15 MHz 30MHz


10/34

10

UMTS

UMTS3rdgeneration

It is based on GSM due to two reasons.

1. The GSM technology dominates the market.

2. Great investment made to GSM should be utilized asmuch as possible.


11/34

11

Some requirements for 3G are :

The system to be developed must be fully

specified(like GSM).The specifications

generated should be valid worldwide.

The system must bring clear added value.it

must be backward compatible at least with

GSM and ISDN.


12/34

12

Multimedia and all of its components must be supported

throughout the system.

The radio access of 3G must be generic. Radio access

and the network infrastructure must not limit the servicesto be generated. That is the technology platform is one

issue and the service using the platform another issue.

3G system has high data rate, that will allow multimediatraffic through the wireless network.


13/34

13

Enhanced packet switching and routing techniques are to

be deployed to support video traffic.

The 3G system will use Broadband Integrated Services

Digital Network (B-ISDN) to provide data services

between the exiting data networks and the wireless

network.

The Global 3G Partnership Project (3GPP) incorporating

many organization (ITU-T, ETSI, ARIB, and ANSI) isdeveloping standards for the 3G systems.


14/34

14

Mobile Communications: Basic Concepts

From ancient to modern times, mankind has been looking

for means of long distance communications.

Fire, flags, horns, etc were used to transmit information

faster.

19th century simplified long distance communications:

Telegraphy and later on Telephony.both technique were

wire line.


15/34

15

Marconi made economic use of electro-magnetic theory by

developing devices for wireless transmission of Morse

signals(about 1985). Already 6 years later, the first

transatlantic wireless transmission of Morse signal tookplace.

Voice was transmitted the first time in 1906 (R.Fess

Eden),and first radio broadcast transmission 1909 in New

York.


16/34

16

Economically most successful wireless

application in the first half of the 20thcentury was

radio broadcast. There is one transmitter, the so

called radio station. Information, such as news,

music etc. is transmitted from the radio station tothe receiver equipment, the radio device. This type

of one way transmission is called simplex

transmission.

In this transmission takes place in one direction,

from the transmitter to the receiver.


17/34

17

The first commercial wireless car phony telephony service

started in the late 1946 in St. Louise, Missouri (USA). It

was a car phone service, because at that time, the mobile

phone equipment was bulky and heavy.

Actually, in the start up, it filled the whole back of the

car. But it was real fullduplex solution.


18/34

18

In the 50ies, several vehicle radio systems were also

installed in Europe.

These systems are now a days called single cell system.

The user data transmission takes place between the

mobile phone and the base station (BS).

A base station transmit and receive user data. While a

mobile phone is only responsible for its users data

transmission and reception, a base station is capable tohandle the calls of several subscribers simultaneously.


19/34

19

Transmission of user data from base station to the

mobile phone is called downlink (DL).

Transmission from mobile phone to base station is

called uplink (UL).

The area, where the wireless transmission between

mobile phone to the base station can take place, is the

base station supply area,called cell.


20/34

20

For conversation, a technical solution is required where

information flow can take place in two directions. This

type of transmission is called Duplex transmission.

Walky-talky was already available the early 30ies. This

system already allowed a transmission of user data in twodirections, but there was a limitation: the users were not

allowed to transmit at the same time.

In other words, you could only receive or transmit the userinformation. This type of transmission is often called semi-

duplex transmission.


21/34

21

For telephony services, a technical solution is required,where subscribers have the impression, that they can

speak (transmit) and hear (receive) simultaneously. This

type of solution is regarded as fullduplex transmission.


22/34

22

Single cell system are quite limited. The more and

more distant the subscriber is from the base station, thelower the quality of the radio link. If the subscriber is

leaving the supply area of the cell, no communication is

possible any more. In order to over come this limitation,

cellular systems were introduced.


23/34

23

A cellular mobile communication system consists of

several cells, which can overlap. By doing so a whole

geographical area can be supported with the mobilecommunication service.

But what happens, when a subscriber moves during a

call from one cell to another cell?


24/34

24

If the subscriber is leaving the cell, and in parallel isentering a new cell, then system makes new radio

resources available in the neighboring cell, and the call is

handed over from one cell to the next one. By doing so,

service continuation is guaranteed, even when thesubscriber is moving. The process is known as

handover(HO).


25/34

25

A hand over takes place during a call i.e. when amobile in active mode.


26/34

26

In the idle mode of mobile, the mobile is switched on,but no resources are allocated to it to allow user data

transmission, and the mobile phone is still listening the

information, broadcast by the base station.

Why? Imagine, there is a mobile terminated call. The

mobile phone is then paged in the cell. This means the

phone receive information that there is a mobile

terminated call.


27/34

27

A cellular system may consists of hundreds of cell. If

the mobile network does not know, in which cell themobile phone is located, it must be paged in all of

them.

To reduce load on networks, paging is done in smallparts of mobile an operators network.

Mobile network operators group cells in

administrative units called location areas (LA).

A mobile phone is paged in only one direction area.


28/34

28

But How does the cellular system know, in which

location area the mobile phone is located?

In every cell, system information is continuously

transmitted. System information includes the location

area information.

In the idle mode, the mobile phone is listening to this

system information.

If the subscriber moves hereby from one cell to the nextcell, and the new cell belongs to the same location area,

the mobile stays idle.


29/34

29

If the new cell belongs to a new location area,

then the mobile phone has to become active. Itstarts a communication with the network

informing it about it new location. This is stored

in database with in the mobile network, and if

there is a mobile terminated call, the networkknows where to page the subscriber.

The process, where the mobile phones informs

the network about its new location is calledLocation Update Procedure (LUP).


30/34

30

First generation mobile communication systems

are:

TACS U.K (Total Access Communication System) 900 MHz band

NMT Scandivanian (Nordic Mobile Telephony) 450 & 900 MHz band

AMPS U.S (Advanced Mobile Phone Service) 800 MHz band

C450

etc.


31/34

31

All of them launched in the 80s of the last century.

1stgeneration mobile communication systems often

offered national wide coverage. But there was

limitations: Most of them did not support roaming.

Roaming is the ability to use another operators network

infrastructure.

International roaming is the ability to go even to another

country and use the locals operators infrastructure.


32/34

32

Most 1st

generation mobile communication systemsonly support only speech transmission, but not data

transmission such as fax.

Supplementary services, well known from ISDN,

were not available, such as number indication and

call forwarding, when busy.

The transmission takes place unprotected via the

radio interfaceas a consequence evaesdropping ispossible.


33/34

33

Finally, mobile communication started to

become a mass market. And the radiointerface is the main bottleneck in terms of

capacity.

Improved solution was urgently required.This led to the inauguration of the second

generation mobile communication systems,

one of which is GSM.


34/34

34

1980 1990 2000

1G 2G 3G

multi standard analog multi standard digital unified standard digital

voice only prepaid data barrier high speed data rate

low data rate up to 2Mb/sTACS,NMT, IS-95,GSM, WCDMA,UMTS,

AMPS CDMA IMT-2000

Terrestrial Terrestrial Satellite/Terrestrial

CXL, M/W OFC, M/W, Cellular Cellular/Satellite

DAMPSU.S 800 MHz Band

GSM Europe 900 / 1800 / 1900 MHz Band

CDMA U S 900 MHz

principle of mc.ppt

Documents