Gsm vs Cdma Presentation

8/3/2019 Gsm vs Cdma Presentation

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Presentation on

GSMand

CDMA


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What is GSM ?

Global System for Mobile (GSM) is a

second generation cellular standarddeveloped to cater voice services and

data delivery using digital modulation


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CellularNetworking technology

that breaks geographicarea into cells shapedlike honey comb

Cell

is the radio coveragearea of one basetransceiver station

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23

4

56

7

6

72

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5

GSM ConceptsCellular Structure


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GSM in World

Figures: March, 2005

37%

1%4%43%

4%

3%

3%

3% (INDIA)

3%

Arab World

Asia Pacific

AfricaEast Central Asia

Europe

Russia

India

North America

South America


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GSM in India

Figures: March 2005

Bharti

27%

BSNL

22%

Spice

4%

IDEA13%

Hutch

19%

BPL

6%

Aircel4%

Reliance

3%MTNL

2%

Bharti

BSNL

Hutch

IDEA

BPL

Aircel

Spice

Reliance

MTNL


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GSM Services

Tele-services

Bearer or Data Services

Supplementary services


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GSM System Architecture

BSC

BSC

MSC

MS

MS

MS BTS

BTS

BTS

GMSC

PSTNISDNPDN

EIRAUC

HLR

VLR


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GSM Actors

PublicSwitchedTelephoneNetwork

BTS

BSS

BSC

Fixed subscriberMobile subscriber

AUC

HLRVLR

MSC

NSS


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GSM System Architecture-I

Mobile Station (MS)Mobile Equipment (ME)

Subscriber Identity Module (SIM)

Base Station Subsystem (BSS)

Base Transceiver Station (BTS)

Base Station Controller (BSC)

Network Switching Subsystem(NSS)

Mobile Switching Center (MSC)

Home Location Register (HLR)

Visitor Location Register (VLR)

Authentication Center (AUC)

Equipment Identity Register (EIR)


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System Architecture

Mobile Station (MS)

The Mobile Station is made up of two entities:

1. Mobile Equipment (ME)

2. Subscriber Identity Module (SIM)


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System Architecture

Mobile Station (MS)

Mobile Equipment

Portable,vehicle mounted, hand held device Uniquely identified by an IMEI (International Mobile

Equipment Identity) used to identify stolen orfraudulently altered phones.

Voice and data transmission

Monitoring power and signal quality of surrounding cellsfor optimum handover

Power level : 0.8W20 W

160 character long SMS.


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System Architecture

Mobile Station (MS) contd.

Subscriber Identity Module (SIM)

Smart card contains the International Mobile SubscriberIdentity (IMSI) used to identify each home user.

Allows user to send and receive calls and receive othersubscribed services

Encoded network identification details

- Key Ki,Kc and A3,A5 and A8 algorithms

Protected by a password or PIN

Can be moved from phone to phonecontains keyinformation to activate the phone


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System Architecture


Base Station Subsystem is composed of two parts that

communicate across the standardized Abis interface allowing

operation between components made by different suppliers

1. Base Transceiver Station (BTS)

2. Base Station Controller (BSC)


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System Architecture


Base Transceiver Station (BTS):

Encodes,encrypts,multiplexes,modulates and feeds the

RF signals to the antenna.

Frequency hopping Communicates with Mobile station and BSC

Consists of Transceivers (TRX) units

Mobile Handoff: B/w two BTSs under the control of the

same BSC, greatly reduces switching burden of MSC.


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System Architecture


Base Station Controller (BSC)

Manages Radio resources for BTS

Assigns Frequency and time slots for all MSs in its area

Handles call set up

Handover for each MS

Radio Power control

It communicates with MSC and BTS


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System Architecture

Network Switching Subsystem(NSS)

Mobile Switching Center (MSC)

Heart of the network

Manages communication between GSM and other networks Call setup function and basic switching

Call routing

Billing information and collection

Mobility management

- Registration

- Location Updating

- Inter BSS and inter MSC call handoff

MSC does gateway function while its customer roams to other networkby using HLR/VLR.

In NSS, there are three different databases called HLR, VLR &

AUC.


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System Architecture

Network Switching Subsystem

Home Location Registers (HLR)

- permanent database about mobile subscribers in a large servicearea(generally one per GSM network operator)

- database contains IMSI,prepaid/postpaid,roamingrestrictions,supplementary services.

Visitor Location Registers (VLR)

- Temporary database which updates whenever new MS enters its area,by HLR database

- Controls those mobiles roaming in its area

- Reduces number of queries to HLR

- Database contains IMSI,TMSI,Location Area,authentication key.


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System Architecture

Network Switching Subsystem

Authentication Center (AUC)

- Protects against intruders in air interface

- Maintains authentication keys and algorithms and provides

security triplets ( RAND,SRES,Kc) >>- Generally associated with HLR and AUC consists of EIR.

Equipment Identity Register (EIR)

- Database that is used to track handsets using the IMEI(International Mobile Equipment Identity)

- Made up of three sub-classes: The White List, The BlackList and the Gray List >>

- Only one EIR per PLMN ( public land mobile network)


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Security Triplets :

RAND : is 128-bit random challenge

generated by the Home Location Register.

SRES : is the 32-bit Signed Responsegenerated by the Mobile Station and the

Mobile Services Switching Center.

Kc : is the 64-bit ciphering key used as aSession Key for encryption of the over-the-

air channel.


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The EIR contains three lists of IMEIs in its

database

white list (handsets allowed to access thenetwork)

grey list (handsets to be observed)

black list (handsets to be barred from

network)

EIR LISTS :


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Radio Link Aspects From Speech to RF Signal

Blah Blah Blah...Blah... Blah... Blah...Digitizing andSource Coding

Channel Coding

Interleaving

Ciphering

Burst Formatting

Modulating Demodulating

Burst De-formatting

Deciphering

De-interleaving

Channel Decoding

Source Decoding


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Characteristics of GSM Standard

Fully digital system using 900,1800 MHz frequency band. TDMA over radio carriers(200 KHz carrier spacing.

8 full rate or 16 half rate TDMA channels per carrier.

These rates are GSM traffic channels & carry digitized

speech or user data.

User/terminal authentication for fraud control.

Full international roaming capability.

Low speed data services (upto 9.6 Kb/s). Compatibility with ISDN (Integrated Services Digital

Network) >>

Support of Short Message Service (SMS).


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Advantages of GSM over Analog system

Capacity increases

Reduced RF transmission power and longer battery life.

International roaming capability due to wide N/w. Better security against fraud (through terminal validation

and user authentication).

Encryption capability for information security and privacy.

Compatibility with ISDN, leading to wider range ofservices & for simultaneous digitaltransmission of voice,

video, data, and other network services over the traditional

circuits of the public switched telephone network.
http://en.wikipedia.org/wiki/Digitalhttp://en.wikipedia.org/wiki/Transmission_(telecommunications)http://en.wikipedia.org/wiki/Public_switched_telephone_networkhttp://en.wikipedia.org/wiki/Public_switched_telephone_networkhttp://en.wikipedia.org/wiki/Transmission_(telecommunications)http://en.wikipedia.org/wiki/Digital


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GSM Applications

Mobile telephony

GSM-R (railway)

-. A sub-system ofEuropean Rail Traffic ManagementSystem (ERTMS), it is used for communication

between train and railway regulation control centers.

Telemetry System

- Fleet management- Automatic meter reading

- Toll Collection

Value Added Services
http://en.wikipedia.org/wiki/European_Rail_Traffic_Management_Systemhttp://en.wikipedia.org/wiki/European_Rail_Traffic_Management_Systemhttp://en.wikipedia.org/wiki/Trainhttp://en.wikipedia.org/wiki/Trainhttp://en.wikipedia.org/wiki/European_Rail_Traffic_Management_Systemhttp://en.wikipedia.org/wiki/European_Rail_Traffic_Management_System


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Future Of GSM

2nd Generation GSM -9.6 Kbps (data rate)

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)

3 Generation

WCDMA(Wide band CDMA)

Data rate : 0.3482.0 Mbps


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Multiple Access Techniques for WirelessCommunications

Multiple Access:

Enable many mobile users to share simultaneously radio

spectrum.

Provide for the sharing of channel capacity between a number

of transmitters at different locations.

Aim to share a channel between two or more signals in such

way that each signal can be received without interference from

another.


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Types of Multiple Access Techniques

Time Division Multiple Access (TDMA)

Code Division Multiple Access (CDMA)

Frequency Division Multiple Access

(FDMA).


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Each signal is modified by multiplying with a large BW

called a spreading signal.

This spreading occurs by combining the transmitter signal

with a spreading sequence which is known as Pseudo noise(PN) sequence, with higher chip rate compared to data rate

of message.

Hence, its a kind of spread spectrum technique.

Spread spectrum multiple access in which each channel isassigned a unique PN code which is orthogonal to PN codes

used by other users.



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Features of CDMA

Many users of a CDMA system share the same

frequency.

Due to high data rates the symbol (chip) duration

is very short and usually much less than the

channel delay spread.

The multipath fading is substantially reduced

because the signal is spread over large spectrum.



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Advantages of CDMA

Increased cellular communications security.

Simultaneous conversations.

Low power requirements and little cell-to-cell coordination needed by operators.

Extended reach - beneficial to rural users

situated far from cells. It provides soft Handoff which can

simultaneously monitor a particular user

from 2 or more Base stations.


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Disadvantages of CDMA

Unlike TDMA, it has soft capacity limit .

i.e. System performance ::1/no. of users.

CDMA is relatively new, and the network is

not as mature as GSM.

CDMA cannot offer international roaming,

a large GSM advantage.

Self jamming & near- far problems.


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What interested military for CDMA ?

CDMA, incorporating spread-spectrum, works by

digitizing multiple conversations, attaching a code

known only to the sender and receiver, and thendicing the signals into bits and reassembling them.

The military loved CDMA because coded signals

with trillions of possible combinations resulted in

extremely secure transmissions.


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Advantages of GSM

GSM is already used worldwide with over 450 million

subscribers.

International roaming permits subscribers to use one phone

throughout Western Europe. CDMA will work in Asia, but not

France, Germany, U.K. and other popular Europeandestinations.

GSM is mature, having started in the mid-80s. This maturity

means a more stable network with robust features. CDMA is still

building its network. GSM's maturity means engineers cut their teeth on the

technology, creating an unconscious preference.

The availability of smart cards (SIM) that provide secure data

encryption give GSM m-commerce advantages.


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Conclusion:

Today, the battle between CDMA and GSM is

muddled. Where at one point Europe clearly

favored GSM and North America, CDMA, the

distinct advantage of one over the other hasblurred as major carriers like AT&T Wireless

begin to support GSM, and recent trials even

showed compatibility between the two

technologies.

GSM still holds the upper hand however. There's

the numerical advantage for one thing: 456 million

GSM users versus CDMA's 82 million


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CDMA GSM

Global market

share: 18% 82%

Storage Type: Internal Memory SIM (subscriber identitymodule) Card

Dominance: Dominant standard in the U.S. Dominant standard worldwideexcept the U.S.

Stands for: Code Division Multiple Access Global System for Mobilecommunication

Comparison chart


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Thanks !


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Questions ?

Date post:	06-Apr-2018
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Gsm vs Cdma Presentation

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