4 cellular networks-__infarastructure

Cellular Networks

& Infrastructure

A Brief Overview

By

Engr. Abdul Razzaque Memon

MCS (IT/MIS); BE (Electronics) ; PE(PEC) ; BA (Arts)

WEB : http : // www.uldhdqpia.webs.com

E-Mail : [email protected]

Cellular Network

Design Issues

By

Engr. Abdul Razzaque Memon

MCS (IT/MIS); BE (Electronics) ; PE(PEC) ; BA (Arts)

WEB : http : // www.uldhdqpia.webs.com

E-Mail : [email protected]

CELLUAR TELEPHONY

What is a Cell?

Cellular Telephony meets

demand multiple users in a

metropolitan (called the

market) by breaking whole

market into several smalle

regions known as CELLS.

Each cell has its own

transmissi tower and set of

assignable communication

channels. A Cell i area

covered by a BASE STATION.

CELLUAR TELEPHONY

Figure showing mobile

telephone tower

CELLUAR TELEPHONY

Question?

Why hexagon is

us as a cell?

Why not

triangle? a

square a circle?

CELLUAR TELEPHONY

Answer – Yes Hexagon

Because to avoid gaps between cells.

If a customer is near the boundary of a cell, it can’t be undertaken by the cell next to it,because of the gap between two cells, therefore communication breakdown occurs.

And also to remain equal distance from a base station to a mobile user.

FREQUENCY REUSE

The same frequency is used by many cell (separated by a distance).

Spectral efficiency (or capacity) is greatly increased.

See next slide . . .

Cellular Network Architect

Example of 2G Digital Cellular

The Global System for Mobile communication . . . .

Network Architecture

(

Mobile Station (MS)

The Cellular (GSM) committee has introduce important powerful innovation by using a S Card in conjunction with a mobile telephone GSM subscribers are provided with a Subs Identity Module card (SIM-Card) with it identification at the very beginning of the s "Confidential information -- may not b or disclosed without permission".

The Mobile Station (MS) includes radio e and the man machine interface (MMI) that subscriber needs in order to access the ser provided by the Cellular (GSM) network.

Mobile Station (MS)

Mobile Station (MS)

The mobile station includes provisions fo communication as well as voice.

Each mobile station has an International Mobile Equipment Identity (IMEI) th permanently stored in the mobile unit. U request, the MS sends this number over signaling channel to the network.

The IMEI is used to identify mobile units are reported stolen or operating incorrect

GSM Architecture

MS Transmission Band : 890 – 915 MHZ

45 MHz

F1 F2 F1' F2'

Frequency

BS Transmission Band : 935 – 960 MHZ

1

2

3

4

5

6

7

8

Year Introduced 1

Access method T

Channel Bandwidth 2

Number of duplex 1

channels

Users per channel 8

Speech coding bit rate 1

Data coding bit rate 1

Frame size 4