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PRESENTATION

ON

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Contents:1. GSM

1.1. What is GSM?

1.2. GSM Phases

1.3. GSM specifications

1.4. GSM system architecture

1.5. GSM network areas

1.6. GSM service area

1.7. Advantages of GSM over Analog system

1.8. GSM Radio technology

2. Cell Planning

2.1. Cell Planning

2.2. Types of cell planning

2.3. Cell Planning Process

2.4. Cell cluster

3.Frequency reuse

3.1.what is frequency reuse

3.2.Example of frequency reuse

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GSM devicesrange from mobile telephones to data cards that allow devices to

connect and communicate with the GSM system.GSM mobile devices may

include the capability to use GSM radio channels on different frequency bands.

Mobile Telephones- Portable devices that can be used for voice

communication.

PCMCIA Air Cards- Cards that can slide into computers to provide data

services.

Embedded Radio Modules- Radio assemblies that can be built-in or installed in

devices such as laptop computers, video cameras, or digital signage displays.

External Radio Modems- Assemblies that can be connected to other devices

through USB, Ethernet, or other connection types to provide data services.

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1.2. GSM PHASES

In the late 1980s, it was decided that GSM would be released in phases to complete

the specifications for the entire range of GSM services & features that originally

planned.

There are three GSM phases; Phase 1, Phase 2 & Phase 2+.

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1.3. GSM Specifications

Frequency bands:

GSM 900:

890 915 MHz: Uplink (MS transmit)

935 - 960 MHz: Downlink (MS receive)

GSM 1800: 1710 - 1885 MHz: Uplink

1805 - 1880 MHz: Downlink

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1.3. GSM Specification(cont.)

Carrier Bandwidth : 200 Khz

Duplex Distance : 45 Mhz

Channels / carrier: 8

No. of RF carriers : 124

Access Method : TDMA/FDMA Modulation Method : GMSK

Modulation data rate : 270.833 Kbps

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1.4. GSM network areas:

In a GSM network, the following areas are defined:

Cell:Cell is the basic service area: one BTS covers one cell. Each cell is given a

Cell Global Identity (CGI), a number that uniquely identifies the cell.

Location Area:A group of cells form a Location Area. This is the area that is

paged when a subscriber gets an incoming call. Each Location Area is assigned aLocation Area Identity (LAI). Each Location Area is served by one or more BSCs.

MSC/VLR Service Area:The area covered by one MSC is called the MSC/VLR

service area.

PLMN:The area covered by one network operator is called PLMN. A PLMN can

contain one or more MSCs.

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1.5. GSM SERVICE AREA

The GSM service area is the entire geographical area in which a subscriber

can gain access to a GSM network. The GSM service area increases asmore operators sign contracts agreeing to work together.

International roaming is the term applied when an MS moves from one PLMN

to another.

fig: relations between areas in GSM10/15/2014 9

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1.6. GSM System Architecture

BSC

BSC

MSC

MS

MS

MS BTS

BTS

BTS

GMSC

PSTN

ISDNPDN

EIR

AUC

HLR

VLR

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1.6. GSM System Architecture(cont.)

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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1.4. GSM system architecture

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1.7. Advantages of GSM over

Analog system

Capacity increases

Reduced RF transmission power and longer battery life.

International roaming capability.

Better security against fraud (through terminal validation anduser authentication).

Encryption capability for information security and privacy.

Compatibility with ISDN, leading to wider range of services

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1.8. GSM Radio Technology

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2.1. What is Cell Planning?

Cell planning means building a network able toprovide service to the customers wherever they

are.The main issue of the cellular network Planneris achieving the maximum capacity whilstmaintaining an acceptable grade of service and

good speech quality.

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Three types of cells are used in cell planning :

Macro cells :Have a typical coverage range from1to 35 km. Normally the site location is on ahilltop or a rooftop.

Micro cells :Have a typical coverage range from0.1 to 1 km , it can maintain indoor coverage inthe lower levels of a building.

Pico cells :It supplies coverage in indoorenvironment. Pico cells are used when thecapacity need is extremely high in certain hotspots.

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2.3. Cell Planning Process

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A frequency used in one cell can be re-used inanother cell at a certain distance. This is known asfrequency re-use.

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References:

Wireless and Cellular Telecommunications

Willium C.Y.Lee

GSM System SurveyEricsson

Wireless Communication

Theodore S.Rappaport (2ndEdition)

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