cellular networks

CELLULAR NETWORKS

HISTORY OF MOBILE PHONES

� Two-way radios (known as mobile rigs) were used in

vehicle.

� During the early 1940s, Motorola developed a

backpacked two-way radio, the Walkie-Talkie and

later developed a large hand-held two-way radio for

the US military. This battery powered "Handie-

Talkie" (HT) was about the size of a man's forearm.

� Later radio telephony was introduced on a large

scale in German tanks during the Second World

War.

EARLY YEARS..

� In 1910 Lars Magnus EricssonLars Magnus EricssonLars Magnus EricssonLars Magnus Ericsson installed a

telephone in his car, although this was not a radio

telephone. While travelling across the country, he

would stop at a place where telephone lines were

accessible and using a pair of long electric wires he

could connect to the national telephone network.

� 1946 soviet engineers G. Shapiro and

I. Zaharchenko successfully tested their version of a

radio mobile phone mounted inside a car. The

device could connect to local telephone network on

a range up to 20 kilometers.

ContdContdContdContd…………

4

EARLY YEARS..� In1945

� The first mobile-radio-telephone service is established in St. Louis, Miss. The system is comprised of six channels that add up to 150 MHz.The project is approved by the FCC, but due to massive interference, the equipment barely works.

� In 1947

� AT&T comes out with the first radio-car-phones that can be used only on the highway between New York and Boston; they are known as push-to-talk phones. The system operates at frequencies of about 35 to 44 MHz, but once again there is a massive amount of interference in the system. AT&T declares the project a failure.

EARLY YEARS….

� In 1973

� Dr. Martin Cooper invents the first personal handset while working for Motorola. He takes his new invention, the Motorola Dyna-Tac., to New York City and shows it to the public. His is credited with being the first person to make a call on a portable mobile-phone.

EARLY YEARS…….

Top of cellular

telephone tower

Dr. Martin Cooper Dr. Martin Cooper Dr. Martin Cooper Dr. Martin Cooper

of MotorolaMotorolaMotorolaMotorola, made

the first US

analogue mobile

phone call on a

larger prototype

model in 1973.

PICTURE GALLRY

The First Mobile Phone: Motorola The First Mobile Phone: Motorola The First Mobile Phone: Motorola The First Mobile Phone: Motorola DynaTACDynaTACDynaTACDynaTAC 8000X 8000X 8000X 8000X

(1983)(1983)(1983)(1983)

Motorola's DynaTAC 8000X wasn't commercially

available until 1983, but its beginnings can be

tracked back to 1973 when the company showed

off a prototype of what would become the world's

first mobile phone. The DynaTAC weighed almost

a kilogram, provided one hour of battery life and

stored 30 phone numbers in its phonebook. The

Motorola DynaTAC is best known for bring used in

the 1987 movie Wall Street, starring Michael

Douglas as corporate raider Gordon Gecko.

PICTURE

First Car Phone: Nokia First Car Phone: Nokia First Car Phone: Nokia First Car Phone: Nokia MobiraMobiraMobiraMobira Senator Senator Senator Senator

(1982)(1982)(1982)(1982)

In the early 1980's, the mobile phone was

best known for its in-car use. Nokia's Mobira

Senator, released in 1982, was the first of its

kind. A car phone that weighed almost 10

kilograms, the Nokia Mobira Senator

resembled a large radio rather than a

conventional mobile phone.

FIRST GSM PHONE: NOKIA 101 (1992)FIRST GSM PHONE: NOKIA 101 (1992)FIRST GSM PHONE: NOKIA 101 (1992)FIRST GSM PHONE: NOKIA 101 (1992)

First GSM Phone: Nokia 101 (1992)First GSM Phone: Nokia 101 (1992)First GSM Phone: Nokia 101 (1992)First GSM Phone: Nokia 101 (1992)

Nokia's 101 was the world's first

commercially available GSM mobile

phone. Paving the way for future "candy-

bar" designs, the 101 had a

monochrome display, an extendable

antenna and a phonebook that could

store 99 phone numbers. It did however

lack Nokia's famous "Nokia tune"

ringtone — this wasn't introduced until

the next model in 1994.

10

EARLY YEARS….� In 1981

� The FCC makes firm rules about the growing cell phone industry in dealing with manufactures. It finally rules that Western Electric can manufacture products for both cellular and terminal use. (Basically they admit that they put the phone companies about 7 years behind)

� In 1988

� One of the most important years in cell phone evolution. The Cellular Technology Industry Association is created and helps to make the industry into an empire. One of its biggest contributions is when it helped create TDMA phone technology, the most evolved cell phone yet. It becomes available to the public in 1991.

TOUCH SCREEN: IBM SIMON PERSONAL TOUCH SCREEN: IBM SIMON PERSONAL TOUCH SCREEN: IBM SIMON PERSONAL TOUCH SCREEN: IBM SIMON PERSONAL

COMMUNICATOR (1993)COMMUNICATOR (1993)COMMUNICATOR (1993)COMMUNICATOR (1993)

Touch Screen: IBM Simon Touch Screen: IBM Simon Touch Screen: IBM Simon Touch Screen: IBM Simon

Personal Communicator (1993)Personal Communicator (1993)Personal Communicator (1993)Personal Communicator (1993)

The IBM Simon Personal

Communicator was one of the

first attempts at a commercially

viable smartphone. A joint

venture between IBM and

Bellsouth, the Simon was only

sold into the US and was best

known for having no physical

keys. It used a touch screen

and optional stylus to perform

the majority of its functions,

which included dialling phone

numbers, sending faxes and

writing memos. It was priced at

$899 when it launched.

GENERATIONS OF MOBILE PHONES

13

INTRODUCTION OF MOBILE TECHNOLOGY

� First Generation (1G)

� Analog system designed for voice only communication. 1G

systems are almost extinct now,

� Second Generation (2G)

� Use GSM and IS-95 CDMA technologies

� CDMA

�Allows users to communicate with different codes

� Still designed for voice communication

14


� 2.5 and 2.75 Generation

� General Packet Radio Service(GPRS )and

CDMA2000 (Phase 1) are belonged to 2.5 G

� Enhanced Data Rates for GSM Evolution(EDGE) is

belonged to 2.75G

� As higher data rate is provided, allows some data

transmission

15


� Third Generation (3G)

� Two 3G, Universal Mobile Telecommunication system(UMTS )and CDMA-2000, are used. UMTS is broadly deployed in Europe and CDMA-2000 is being deployed in North American and parts in Asia

� Higher data transmission rate (up to 2Mbps) which allows video conferencing

16


� Forth Generation (4G)

� Combined the technologies of Wireless local area

network (will be introduced soon) and 3G

THE CELLULAR CONCEPT

BASIC CONCEPT

� Cellular system developed to provide mobile telephony:

telephone access “anytime, anywhere.”

� First mobile telephone system was developed and

inaugurated in the U.S. in 1945 in St. Louis, MO.

� This was a simplified version of the system used today.

SYSTEM ARCHITECTURE

� A base station provides coverage (communication capabilities) to users on mobile phones within its coverage area.

� Users outside the coverage area receive/transmit signals with too low amplitude for reliable communications.

� Users within the coverage area transmit and receive signals from the base station.

� The base station itself is connected to the wired telephone network.

FIRST MOBILE TELEPHONE SYSTEM

One and only one

high power base

station with which all

users communicate.

Entire Coverage

Area

Normal

Telephone

System

Wired connection

CELLULAR GEOMETRIES

Rd 3=

• The most common model used for wireless networks

is uniform hexagonal shape areas

– A base station with omni-directional antenna is placed in

the middle of the cell

PROBLEM WITH ORIGINAL DESIGN

� Original mobile telephone system could only support a

handful of users at a time…over an entire city!

� With only one high power base station, users phones

also needed to be able to transmit at high powers (to

reliably transmit signals to the distant base station).

� Car phones were therefore much more feasible than

handheld phones, e.g., police car phones.

IMPROVED DESIGN

� Over the next few decades, researchers at AT&T Bell Labs

developed the core ideas for today’s cellular systems.

� Although these core ideas existed since the 60’s, it was

not until the 80’s that electronic equipment became

available to realize a cellular system.

� In the mid 80’s the first generation of cellular systems was

developed and deployed.

THE CORE IDEA: CELLULAR CONCEPT

� The core idea that led to today’s system was the cellular

concept.

� The cellular conceptThe cellular conceptThe cellular conceptThe cellular concept: multiple lower-power base stations

that service mobile users within their coverage area and

handoff handoff handoff handoff users to neighboring base stations as users move.

Together base stations tessellatetessellatetessellatetessellate the system coverage

area.

CELLULAR CONCEPT

� Thus, instead of one base station covering an entire city,

the city was broken up into cellscellscellscells, or smaller coverage

areas.

� Each of these smaller coverage areas had its own lower-

power base station.

� User phones in one cell communicate with the base

station in that cell.

3 CORE PRINCIPLES

� Small cells tessellate overall coverage area.

� Users handoff as they move from one cell to another.

� Frequency reuse.

SUMMARIZATION

1G 2G 2.5G 3G 3.5G 4G

Speeds n/a <20Kbps 30Kbps to 90Kbps

144Kbps to 2Mbps

384Kbps to 14.4Mbps

100Mbps to 1Gbps

Features Analog (voice only)

Voice; SMS; conference calls; caller ID; PTT

MMS; Images; Web browsing; Short audio video clips; games; apps; Ring tone downloads

Full motion video; streaming music; 3D gaming; faster Web browsing

On-demand video; video conferencing

High-quality streaming video, HQ video conferencing; VOIP telephony

Technology AMPS GSM CDMA iDen

GPRS 1xRTT EDGE

UMTS 1xEV-DO HSPDA 1x-EV-DV WiMax

Time 1980 1990 – 1995 1995 – 2000 2000 – 2005 2005 + TBA

TECHNOLOGY USED IN CELLULAR

NETWORK

WHAT IS GSM ?

Global System for Mobile (GSM) is a second

generation cellular standard developed to cater

voice services and data delivery using digital

modulation

GSM: HISTORY

• Developed by Group Spéciale Mobile (founded 1982) which was an initiative of CEPT ( Conference of European Post and Telecommunication )

• Aim : to replace the incompatible analog system

• Presently the responsibility of GSM standardization resides with special mobile group under ETSI ( European telecommunication Standards Institute )

• Full set of specifications phase-I became available in 1990

• Under ETSI, GSM is named as “ Global System for Mobile communication “

• Today many providers all over the world use GSM (more than 135

countries in Asia, Africa, Europe, Australia, America)

• More than 1300 million subscribers in world and 45 million subscriber in India.

6-31

CODE DIVISION MULTIPLE ACCESS (CDMA)

� used in several wireless broadcast channels (cellular, satellite, etc) standards

� unique “code” assigned to each user; i.e., code set partitioning

� all users share same frequency, but each user has own “chipping” sequence (i.e., code) to encode data

� encoded signal = (original data) X (chipping sequence)

� decoding: inner-product of encoded signal and chipping sequence

� allows multiple users to “coexist” and transmit simultaneously with minimal interference (if codes are “orthogonal”)

CDMA

THE MOST ADVANCED WIRELESS

DIGITAL TECHNOLOGY

. . . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . . .

1G 1G 1G 1G

AnalogAnalogAnalogAnalog

2G 2G 2G 2G

Time DivisionTime DivisionTime DivisionTime Division(TDMA & GSM)(TDMA & GSM)(TDMA & GSM)(TDMA & GSM)

3 3 3 3 –––– 7x Analog Capacity7x Analog Capacity7x Analog Capacity7x Analog Capacity

3G 3G 3G 3G

Code DivisionCode DivisionCode DivisionCode Division(CDMA2000(CDMA2000(CDMA2000(CDMA2000®, WCDMA), WCDMA), WCDMA), WCDMA)

20 20 20 20 –––– 26x Analog Capacity26x Analog Capacity26x Analog Capacity26x Analog Capacity

CDMA2000 BENEFITS FOR OPERATORS,

SUBSCRIBERS AND GOVERNMENTS

� CDMA is a high-speed wireless data and voice

network solution for low-cost, easy to deploy,

high-performance services, that address the

needs of governments, operators and

subscribers

� CDMA can support high volumes of voice traffic and

high-speed data traffic;

Contd.

....ContdContdContdContd

� Instead of being limited to a narrow channel structure in a given frequency, CDMA spreads signal across 1.25 MHz of the spectrum, and simultaneously transmits unique, digitally encoded and encrypted signals over the same radio frequency (RF) carrier;

� CDMA2000 technology can be configured for data and/or voice, as well as for fixed or mobile services.

� Due to its efficient use of the spectrum to provide high-quality voice and high-speed data services, CDMA can be utilized for fixed voice and data services, delivering end-users the richness and variety of the Internet with the quality and reliability of the traditional phone network.

OFDM

� Divides the spectrum into a number of equally spaced tones.

� Each tone carries a portion of data.

� A kind of FDMA, but each tone is orthogonal with every other tone. Tones can overlap each other.

� Example: 802.11a WLAN

3G WIRELESS SYSTEMS

� 3G Wireless Systems are the new generation of

systems that offer high bandwidth and support digital

voice along with multimedia and global roaming.

� Globally, different systems are being used, so, to

migrate to globally acceptable systems, numerous

standardization activities were carried out and three

systems emerged: W-CDMA, CDMA2000, and TD-

SCDMA

Communication services

•Video telephony

•Video conference

•Personal location (GPS)

Education

•Virtual schools

•On-line science lab

•On-line library

•On-line language labs

•Training

Applications Using 3GApplications Using 3GApplications Using 3GApplications Using 3G

Finance services

•Virtual banking

•On-line billing

•Universal USIM and credit card

Business services

• Mobile office

•Narrowcast business TV

•Virtual workgroups

•Expertise on tap

Entertainment

•Audio on demand

•Games

•Video clips

•Virtual sightseeing

Applications Using 3G…Applications Using 3G…Applications Using 3G…Applications Using 3G…

3G CONCLUSION

� 3G technologies promise to deliver a lot and are slowly being put into effect.

� We have already started seeing the early features of 3G technologies being implemented in our phones, i.e., the video phones in the market.

� It remains to be seen how much of the promised features and applications are actually implemented in today’s economy.

� However, they have been slow in coming in. Let’s see what the future holds…

cellular networks

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