Chapter 1 Junaid

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M. Junaid Mughal January, 2006

Wireless CommunicationsPrinciples and Practice

2nd Edition

Prentice-Hall

Chapter 1: Introduction to Wireless

Communication Systems


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Growth of Mobile communications Industry

What are the factors that fueled the growth of mobile communication industry?

Digital and RF circuit fabrication improvement Large scale circuit integration

Miniaturization technologies

Digital Switching techniques


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Evolution of Mobile Radio Communications

Factors which has an impact on the evaluation of Mobile Radio Communication

Government regulatory agenciese.g., licensing, spectrum allocation

Competitors

new products and services, e.g., music, picture, camera in mobile phone

Subscribers

demand services in far flung areas etc.


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Cellular Concept developed by Bell Labs in 1960s and 70s

Recent Growth in Cellular Telephony is due to the development of

highly reliable, miniaturization and development of solid state radio

frequency hard ware in 1970s

Future Growth will depend on

radio spectrum allocation

regulatory decisions which support new and extended services

consumer needs

Technology advances in signal processing

Technology advances in Network area

Growth of Mobile Telephony


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The growth of mobile telephony as compared with

other popular inventions of the 20th century


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Radio Frequency

Common frequency bands include the following:

AM radio - 535 kilohertz to 1.7 megahertz

Short wave radio - bands from 5.9 megahertz to 26.1 megahertzCitizens band (CB) radio - 26.96 megahertz to 27.41 megahertz

Television stations - 54 to 88 megahertz for channels 2 through 6

FM radio - 88 megahertz to 108 megahertz

Television stations - 174 to 220 megahertz for channels 7 through 13


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Mobile Radiotelephone in the US

First Public mobile telephone service introduced in 1946

Single transmitter with coverage of 50km

120kHz simplex channel

1940s Channel RF bandwidth was 120 kHz (single channel)

1950, FCC doubled the channels in the same bandwidth with channel bandwidth

reduced to 60 kHz

1960, bandwidth was reduced to 30 kHz

1950s and 60s automatic channel trunking was introduced and implemented under

the label IMTS (Improved Mobile Telephone Service)

1976 Bell Mobile Phone service has only 12 channels and could provide service to

543 paying channels

1968, Bell labs proposed the idea of cellular phone to FCC

1983, FCC allocated 666 duplex channels (666 x 30kHz x 2 = 39.96 MHz = 40MHz

in the 800MHz band) for the US Advanced Mobile Phone System (AMPS)

Two service providers in each city with half the channels


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Mobile Radiotelephone in the US

1989, FCC allocated additional 166 channels (166 x 30kHz x 2 = 9.96MHz =

10MHz)

Total channels 666+166 = 832, with bandwidth of 50 MHz (really it is 833

channels)

Used FDMA (Frequency Division Multiple Access)


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Frequency Allocation in the US for AMPS


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Major Mobile Radio Standards in North

America


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Major Mobile Radio Standards in Europe


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Major Mobile Radio Standards in Japan


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Wireless Communications System

Definitions:


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Wireless Communications System

Definitions:


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A wide area paging system


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A Cordless Telephone System


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A Cellular System


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Definitions/Acronyms

CAI: Common Air Interface

For communication between the base station and the mobile

It has 4 different channels

1. FVC: Forward Voice Channel

2. RVC: Reverse Voice Channel

3. FCC: Forward Control Channel

4. RCC: Reverse Control Channel

** Control channels are often called setup channels

** Control channels make up about 5% of the total channels


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Definitions/Acronyms (contd.)

MSC: Mobile Switching Centeralso called

MTSO: Mobile Telephone Switching office

PSTN: Public Switched Telephone Network


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How a Cellular Telephone Call is Made

From Land line to Mobile

PSTN MSC

MIN: mobile identification number

MIN

FCC

MIN

RCCFree channels


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Timing Diagram Illustration for

Call from Land line to Mobile


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How a Cellular Telephone Call is Made

From Mobile to Land line

PSTN MSC

MIN: mobile identification number

Free channels

MIN/telephone #

RCC

MIN/telephone


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Timing Diagram Illustration for

Cal from Mobile to Land line


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Comparison of Mobile Communication

System- Mobile Station


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Comparison of Mobile Communication

System- Base Station


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Linear Cells as an Example

of Frequency Reuse

For acceptable voice quality Signal to Interference ratio

P/I > 50 (17dB)

f1 f2 f3 f1 f2 f3

P I

Cell 1 Cell 2 Cell 3 Cell 1 Cell 2 Cell 3

Region 1 Region 2

Total Band width (BW) is divided into three adjacent bands f1,f2 and f3Such that BW = f1+f2+f3


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Frequency Reuse for

Area Coverage

12

3 4

5

67

12

3 4

5

67

12

3 4

5

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Base Station (BS)

Chapter 1 Junaid

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