global syastem for mobile

8/9/2019 global syastem for mobile

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GLOBAL SYSTEM FOR

MOBILE


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HISTORY

The Europeans realized this early on,

and in 1982 the Conference of

European Posts and Telegraphs (CEPT)

formed a study group called the Groupe

Spcial Mobile (GSM) to study and

develop a pan-European public land

mobile system. The proposed systemhad to meet certain criteria:


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PURPOSES

Good subjective speech quality

Low terminal and service cost

Support for international roaming

Ability to support handheld terminals

Support for range of new services and

facilities

Spectral efficiency

ISDN compatibility


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ARCHITECTUREARCHITECTURE


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GSM network consists of the followingcomponents:

Mobile station. The GSM mobile station (ormobile phone) communicates with other parts ofthe system through the base-station system.

SIM:Subscriber Identification Module. A SIM cardcontains its unique serial number, internationalunique number of the mobile user (IMSI), securityauthentication and ciphering information,temporary information related to the local network

(also temporary local id that has been issued tothe user), a list of the services the user hasaccess to and two passwords (PIN for usual useand PUK for unlocking).


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GSM Base station system (BSS).

Base transceiver station (BTS). The basetransceiver station (BTS) handles the radiointerface to the mobile station. The basetransceiver station is the radio equipment(transceivers and antennas)

Base station controller (BSC). The BSCprovides the control functions and physicallinks between the MSC and BTS. Itprovides functions such as handover, cellconfiguration data and control of RF powerlevels in base transceiver stations. Anumber of BSCs are served by a MSC


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GSM Switching System

Mobile services switching center (MSC). TheMSC performs the telephony switching functionsof the system. It also performs such functions asnetwork interfacing, common channel signalling,

and others.

Home location register (HLR). The HLRdatabase is used for storage and managementof subscriptions. The home location register

stores permanent data about subscribers,including a subscriber's service profile, locationinformation, and activity status.


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Visitor location register (VLR). The VLR

database contains temporary informationabout subscribers that is needed by themobile services switching center (MSC) inorder to service visiting subscribers. When

a mobile station roams into a new mobileservices switching center (MSC) area, thevisitor location register (VLR) connected tothat MSC will request data about themobile station from the HLR, reducing the

need for interrogation of the home locationregister (HLR).


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Authentication center (AUC). The AUC

provides authentication and encryptionparameters that verify the user's identityand ensure the confidentiality of each call.The authentication center (AUC) alsoprotects network operators from fraud.

Equipment identity register (EIR). The EIRdatabase contains information on the

identity of mobile equipment to preventcalls from stolen, unauthorized or defectivemobile stations.


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CALL INPROGRESS-

STEPS 1) MS initialization after switched-on

2) Service request

3) Authentication and security 4) MS attach and detach

5) Location update

6) Outgoing voice call 7) Incoming voice call

8) SMS and special services

9) Call hand over


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GSM SPECIFICATIONS-1

RF SpectrumGSM 900

Mobile to BTS (uplink): 890-915 MhzBTS to Mobile(downlink):935-960 Mhz

GSM 1800Mobile to BTS (uplink): 1710-1785 MhzBTS to Mobile(downlink): 1805-1880Mhz


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GSM SPECIFICATIONS-2

Carrier Separation : 200 Khz

Duplex Separation : 45 Mhz No. of RF carriers : 124

Access Method : TDMA/FDMA

Modulation Method : GMSK Modulation data rate : 270.833 Kbps


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FDMA

Frequency Division Multiple

Access orFDMA is a channel access

method used in multiple-access

protocols as a channelization protocol.

FDMA gives users an individual

allocation of one or several frequency

bands, orchannels


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TDMA

Time division multiple access (TDMA)

is a channel access method for shared

medium networks. It allows several

users to share the samefrequencychannel by dividing the signal into

different time slots. The users transmit in

rapid succession, one after the other,each using his own time slot.


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EVOLUTION


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1-G

1G (or 1-G) refers to the first-generation

ofwireless telephone technology, mobile te

lecommunications.

The 1G system in GSM all power

allocation and handoffs strategies were

decided by MSC and then executed byBSC.


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2-G

GSM differs from its predecessors in that

both signaling and speech channels

are digital, and thus is considered a second

generation (2G) mobile phone system.

GSM also pioneered a low-cost (to the

network carrier) alternative to voice calls,the short message service (SMS, also called

"text messaging").


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The basic difference is that the

interfernce of MSC is reduced

as compared to 1-G the

power and handoff allocationdepends on THE BSC unless

in the case of roaming where

the MSCs are different.


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2.5-G

2.5 Generation ( Future of GSM)

HSCSD (High Speed ckt Switched

data)

Data rate : 76.8 Kbps (9.6 x 8 kbps)

GPRS (General Packet Radio service)

Data rate: 14.4 - 115.2 Kbps

EDGE (Enhanced data rate for GSM

Evolution)

Data rate: 547.2 Kbps (max)


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HSCSD-High-speed circuit-switched data

is the ability to use multiple time slots at

the same time. Using the maximum of fourtime slots, this can provide an increase in

maximum transfer rate of up to 57.6 kbit/s.

GPRS General Packet Radio Service

(GPRS) is a packet oriented Mobile Data

Service available to users of GlobalSystem for Mobile Communications

(GSM).


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GPRS can be used for services such

as WAP access, SMS, MMS, and forInternet communication services

such as email and World Wide Web

access. 2G cellular systemscombined with GPRS are often

described as "2.5G", that is, a

technology between the second (2G)

and third (3G) generations of mobile

telephony.


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EDGE Enhanced Data rates for

GSM Evolution (EDGE) is a digital

mobile phone technology that

allows increased data transmission

rates and improved data

transmission reliability. EDGE is

generally classified as 2.75G,

although it is part of the 3G

definition.


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3-G

3G is the third generation of telecommunicationhardware standards and general technology

for mobile networking.

3G networks enable network operators to offer

users a wider range of more advanced

services while achieving greater network

capacity through improved spectral efficiency.

Services include wide-area wireless voice

telephone, video calls, and broadband wireless

data, all in a mobile environment.


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Additional features also include HSPA data

transmission capabilities, which provides

users with data rates up to 14.4 Mbit/s on

the downlink and 5.8 Mbit/s on the uplink.

HSPA:High-Speed Packet Access (HSPA)is a 3G mobile telephony communications

protocol in the HSPA family, which allows

networks based on Universal Mobile

Telecommunications System (UMTS) to

increase data capacity and speed up

transfer rates.


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HSPA+ - HSPA+, also known as Evolved

HSPA is a wireless broadband standard

that provides HSPA data rates up to 42Mbit/s on the downlink and 22 Mbit/s on the

uplink .

UMTS Universal Mobile

Telecommunications System (UMTS) is one

of the third-generation (3G) cell phone

technologies, which is also being developedinto a 4G technology. It is closely related to

GSM/EDGE as it borrows and builds upon

concepts from GSM


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4-G

4G working group has defined the

following as objectives of the 4G

wireless communicationstandard:

A spectrally efficient system .

High network capacity: moresimultaneous users per cell.


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A nominal data rate of 100 Mbit/s

while the client physically moves athigh speeds relative to the station,

and 1 Gbit/s while client and station

are in relatively fixed positions as

defined by the ITU-R.

A data rate of at least 100 Mbit/s

between any two points in the world.

Smooth handoffacrossheterogeneous networks.


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Seamless connectivity and

global roaming across multiplenetworks.

High quality of service for next

generation multimedia support (real timeaudio, high speed data, HDTV video

content, mobile TV, etc).

Interoperability with existing wirelessstandards.

IP, packet switched network.


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LTE Long Term Evolution (LTE) is the

name given to a project to improve theUMTS mobile phone standard to cope

with future technology evolutions. Goals

include improving spectral efficiency,lowering costs, improving services,

making use of new spectrum and

reframed spectrum opportunities, and

better integration with other openstandards.


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CDMA

CDMA employs analog-to-digital conversion(ADC) in combination with spread

spectrum technology. Audio input is first

digitized into binary elements. The frequency of

the transmitted signal is then made to vary

according to a defined pattern (code), so it can

be intercepted only by a receiver whose

frequency response is programmed with thesame code, so it follows exactly along with the

transmitter frequency. There are trillions of

possible frequency-sequencing codes, which

enhances privacy and makes cloning difficult.


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CDMA CELL


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GSMCELL


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THANX

global syastem for mobile

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