Group System for MobileGroup System for Mobile

OROR

Global System for MobilesGlobal System for Mobiles

HISTORY INTRODUCTION CELLULAR COMPONENTS GSM COMPONENTS NETWORK STRUCTURE SUBSCRIBER IDENTITY MODULE GSM SECURITY ADVANTAGES OF GSM DISADVANTAGES OF GSM

CONTENTSCONTENTS

The European Conference of Postal and Telecommunications Administrations (ECPT) created the Group Special Mobile (GSM) to develop a standard for a mobile telephone system that could be used across Europe.

The first GSM network was launched in 1991 by Radio-Linja in Finland with joint technical infrastructure maintenance from Ericsson.

HISTORYHISTORY

INTRODUCTIONINTRODUCTION

GSM is a cellular network, which means that mobile phones connect to it by searching for cells in the immediate vicinity.

Time Division Multiple Access(TDMA) Frequency Division Multiple

Access(FDMA) 3 billion people across more than 212

countries and territories.

Cellular ComponentsCel lular Components

Cell Site(Base Station Equipment) Frequency System

Cell SiteCel l Site

Large CellsLarge Cells• 32 kms• High Transmission

Power• Few Subscribers Smart CellsSmart Cells• 0.8 kms• Urban Areas• Many Subscribers

Cel l TypesCel l Types There are five different cell sizes in a GSM network—macro,

micro, pico, femto and umbrella cells. Macro cells can be regarded as cells where the base station

antenna is installed on a mast or a building above average roof top level.

Micro cells are cells whose antenna height is under average roof top level; they are typically used in urban areas.

Picocells are small cells whose coverage diameter is a few dozen meters; they are mainly used indoors.

Femtocells are cells designed for use in residential or small business environments and connect to the service provider’s network via a broadband internet connection.

Umbrella cells are used to cover shadowed regions of smaller cells and fill in gaps in coverage between those cells.

GSM operate on four different frequency ranges.

GSM operate in 890 MHz - 960 MHz bands. In GSM network there are two frequencies:-1. Uplink Frequency (890 MHz – 915 MHz)2. Downlink Frequency (935 MHz – 960 MHz)3. Frequency Channel = 124 (200kHz B/W)

Frequency SystemFrequency System

GSM Network ComponentsGSM Network Components

The Mobile Station The Base Station System The Network Switching System

Mobile Station (MS)Mobile Station (MS) Mobile Equipment(ME)

1. Vehicle Mounted

2. Portable Mobile Unit

3. Handportable Unit

Subscriber Identity Module Subscriber Identity Module (SIM)(SIM)

1. International Mobile Subscriber Identity-IMSI

2. Temporary Mobile Subscriber Identity-TMSI

3. Location Area Identity-LAI

4. Subscriber Authentication Key-KI

5. Mobile Station International Services Digital Network-MSISDN

Base Station SystemBase Station System

Connection b/w ME and MSC Its Components:- Base Station Controller(BSC)

1. Contains 40 BTSs.

2. Handover phone signal without involving MSC.

Base Tranreceiver Station(BTS) Make connection with mobiles

The Network Switching The Network Switching SystemSystem

Mobile Services Switching Centre-MSC Home Location Register-HLR Visitor Location Register-VLR Equipment Identity Register-EIR Authentication Centre-AUC InterWorking Function-IWF Echo Canceller-EC

The network behind the GSM system seen by the customer is large and complicated in order to provide all of the services which are required.

The Base Station Subsystem (the base stations and their controllers).

The Network and Switching Subsystem (the part of the network most similar to a fixed network). This is sometimes also just called the core network.

The GPRS Core Network (the optional part which allows packet based Internet connections).

All of the elements in the system combine to produce many GSM services such as voice calls and SMS.

NETWORK STRUCTURENETWORK STRUCTURE

Subscriber Identity ModuleSubscr iber Identity Module

One of the key features of GSM is the Subscriber Identity Module (SIM), commonly known as a SIM card.

The SIM is a detachable smart card containing the user's subscription information and phonebook. This allows the user to retain his or her information after switching handsets

GSM SECURITYGSM SECURITY GSM was designed with a moderate level of

security. PIN (Personal Identity Number) Password PIN2 (Personal Identity Number) Password PUK (Personal Unlock Keyword) Password

(e.g.,14468400)

Call Costs are becoming lower and lower everyday. Call quality is much more pure and secure in GSM. More and more value-added services like GPRS,

EDGE etc are coming everyday. Power is less consumed in GSM handsets compared

to CDMA handsets. If u have a tri-band GSM phone u can use it in

almost any part of the world.

Call costs will still remain higher compared to CDMA. Roaming costs are much lower in CDMA compared to GSM.

GSM phones can be tampered with. They have their unique IMEI number which is used to lock the phone permanently but now a days software’s are available which can tamper them too.

If your SIM is lost then all data is lost unless u have it stored in the phone’s memory.

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