THE DEVELOPMENT OF CELLULAR MOBILE COMMUNICATION SYSTEMS

By: Yusuf Kurniawan

I. Introduction

Nowadays, to get in touch with someone who is mobile is not a problem any

more. If we could not call him at home we can contact him while he is on the

move. Whether he is in a remote place out of reach of the telephone line or just on

his way to work, we can still give him a ring. The condition at present differs

greatly compared to the 1940s, when the basic cellular concept was developed.1

Cellular phones or mobile phones are now widely used by a lot of people in

all over the world. From year to year the number of mobile phones subscribers

increases. For example in the United Kingdom in the end of 1992 there were 1.4

million subscribers,

The cellular mobile communication system enables the beginning of the wireless

communication.

2 then in 1993 the number became 1.8 million.3 It is a

tremendous figure in the growing number of cellular phones subscribers. Based on

the data in the International Institute of Communications (IIC), World Bank,

Britain sat in the second position of having the largest cellular phones subscribers

after the United States in 1989.4 According to the poll conducted during 30 March

– 2 April 2000 half of all Americans own a cellular phone.5

1 http://www.wave-guide.org/archives/waveguide_3/cellular-history.html 2 Central Office of Information, Aspects of Britain. (London:1994).p. 7. 3 Central Office of Information in Lax, S. Beyond the Horizon.(Luton:1997).p.20. 4 Central Office of Information, Aspects of Britain. (London:1994).p.8

5 http://www.gallup.com/poll/releases/pr000426.asp

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The development of the cellular mobile communication system recently is

very fast. The network providers of cellular phones are now ubiquitous in every

country in all over the world. The rapid development and diffusion of the cellular

mobile communication system virtually can not be separated from the previous

development of the telecommunication systems, namely electronic telegraphy,

radio and telephone. Even though the result of technological development were

not planned before, it is important to consider the previous communication

devices. Started from the infancy of the telegraph until the maturity of cellular

mobile communication, it is a span of inseparable history. This essay tries to

reveal the historical and technological development of the cellular mobile

communication system since its infancy up to the present time.

II. Analysis

The development of cellular mobile communication system can be interpreted

very broadly. This essay is not going to look at the development in a certain

country but in general, since there are several countries take the lead of

developing cellular mobile communication system such as the United States and

Japan.

Let us have a look at a glance to the development of the electric telegraph

network. The nature of sending a message through a span of wire electronically

inspired Alexander Graham Bell to set up a new telecommunication system called

telephone. There are two versions actually who invented the telephone, Alexander

Graham Bell or Elisha Gray. Because on the same day, 14 February 1876 they

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both patented their inventions in Washington.6 Telephone uses spoken message

instead of written as it is used in the telegraph system. Most of all, the invention

of the telephone has brought the telecommunication advancement one more step

ahead after the telegraphy. The phenomenon of there will be an advanced new

technology in communication has actually been started in 1851 when the Thomas

Crampton’s Submarine Telegraph Company successfully laid a cable across the

sea, from Dover to Calais.7

One of the key elements which cause the rapid development of the cellular

mobile communication system is the invention of optical fibres. Optical fibres

which were invented in 1964 are ‘tiny strands of ultra-pure glass which can carry

voice, data, text and images in digital format’. Moreover ‘they also can carry a

large amounts of digital information including thousands of telephone calls on

pulses of light’.

The submarine cables which formerly functioned as

the electronic telegraph network then were improved to convey telephone signals.

And the quality of the cables did gradually improved from copper to coaxial

cables and then to optical fibres. Then, by combining the mobile radio system and

a certain band, the cellular mobile communication system could be actualised for

daily communication.

8

6 Flichy, P. Dinamics of Modern Communications. (London:1995).p. 82.

Compared to the predecessor, copper and coaxial cables, optical

fibres obviously exceed in all aspects. Optical fibres have many excellence in the

voice clearness, amounts of calls they can carry, very low level of interference,

speed of pulses and many others that copper and coaxial cables do not have like

data and image transfer. The only thing that might be still a consideration for

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some cellular phones network providers is probably the cost which is much more

expensive compared with coaxial cables.

Cellular mobile communication is also called wireless communication since

it does not need wire to call. The term ‘wireless’ was actually inspired by

Gulielmo Marconi when in 1894 he succeeded to tap out a message in Morse

Code. And as a response to the signal, a bell rang at the other end of the room. It

was because the signal travelled through the air. Then he called it ‘Wireless’.9

Thus because Bell’s telephone wires could carry the human voice, then scientists

began to search for ways Marconi’s invention could broadcast speech too. And

then in 1906, Reginald Fessenden managed to do it by changing sound waves into

signals through a process called amplitude modulation (AM). In 1935 Edwin

Armstrong, from the United States, introduced FM (frequency modulation) radio

waves. Since FM used less power, and smaller, lighter receivers, wireless was on

the move.10

a. Period of the 1920s – 1950s

II.1. Cellular Background

The development of cellular mobile communication system had actually been

commenced in the early of the 1920s (exactly in 1921) when mobile radio

communication was used in a vehicle by Detroit Michigan Police Dept.11

7 Headrick, D.R. The Invisible Weapon. (New York:1991).p. 15. 8 Central Office of Information, Aspects of Britain. (London:1994).p. 33. 9 http://www.cellularone.com/pages/library/history.html 10 http://www.cellularone.com/pages/library/history.html

However the channels got overcrowded very quickly since it was operated at a

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frequency of 2 MHz. Then the next event of important development also occurred

in the United States was the inauguration of the first public mobile telephone

system in the US. It had three channels at 150 MHz.12 But the interference still

happened and the equipment still could not solve the problem because the

technology at that time did not yet exist to overcome the problems that appeared.

Until the 1920s most of the mobile radio communications used Morse-coded on-

off keying.13 In the early development, mobile telephone handsets were still very

heavy, bulky and noisy. Because they were operated in the lower frequency part

of the VHF band and the range was about ten miles.14

b. Period of the 1950s – 1960s

During this period there was a large increase in bandwidth and switching

technology used by the workstations and. For instance in 1956 ’12 wire line

channels were added near 450 MHz.’ And the automatic capability was extended

to the 450 MHz band in the late of the 1960s. It was called “Improved Mobile

Telephone System”, and became the standard for mobile telephone service in the

US.15

c. Period of the 1970s – 1980s

This was the period of the more advanced cellular mobile communication system.

It was in 1970 when FCC announced a tentative allocation of 75 MHz in the 800

MHz region.16

11 http://www.wave-guide.org/archives/waveguide_3/cellular-history.html 12 http://www.wave-guide.org/archives/waveguide_3/cellular-history.html 13 Steele, Raymond. Mobile Radio Communications. (London:1992).p. 1 14 Steele, Raymond. Mobile Radio Communications. (London:1992).p. 1 15 http://www.wave-guide.org/archives/waveguide_3/cellular-history.html 16 http://www.wave-guide.org/archives/waveguide_3/cellular-history.html

And FCC asked some industries to submit their proposals to obtain

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communication goals and as well as to demonstrate feasibility. One monumental

event occurred when The Illinois Bell Telephone company was awarded a licence

to operate a developmental cellular system in 1977. And between 1974 and 1981

AT&T Bell Labs collaborated with other cellular terminal vendors to develop

their cellular phones so that consumers would be able to use their mobile phone

on the cellular network.17 And on October 13, 1983 the first call on a commercial

cellular system was built in Chicago.18

d. Period of the 1980s – present

Based on the development of the cellular mobile communication system in

the first three periods, the most fundamental problem that still existed was

bandwidth –the measure of a communication channel.

During this period the development of cellular mobile communication system has

been diffusing very rapidly. The big mobile phones manufacturers like Ericsson,

Nokia, Siemens, Motorola and NEC began to adopt and applied new technologies

in their products and to maximaze the quality of sending and reception in their

mobile phones. The development achieved by cellular mobile phone companies

during this period showed a great achievement. Especially during the last ten

years the development of cellular mobile communication system has been very

sophisticated. A cell phone now can be combined with internet. We could be E-

mailing from our purses and downloading from our pockets. With WAP (Wireless

Application Protocol) phones a mobile phone subscriber can access information in

17 http://www.wave-guide.org/archives/waveguide_3/cellular-history.html 18 http://www.cellularone.com/pages/library/history.html

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the internet from his mobile phone. More than that, with WAP technology even

one can do shopping just from his fingertip.

Also in this period, mobile phones subscribers are excited by the emergence

of SMS (short message service) that makes them able to send and receive

messages to and from other cellular phones. In addition, nowadays there are many

ASP (Application Service Protocol) that provide service to send sms, one can

send short message to other mobile phones in one country or to all over the world

such as www.lycos.co.uk and www.mtnsms.com. Lycos could deliver message to

mobile phones in the whole UK with 130 maximum characters long. While using

mtnsms one could deliver messages to cellular phones to all over the world with

140 characters long. Even, with mtnsms the subscriber who receives a message

could reply it. And the sender would be able to find out the reply message in his

mtnsms account. And all of these services are mostly delivered within under ten

seconds. These advancements in the technology of cellular mobile communication

has enticed more new subscribers to subscribe to cellular phones.

Along with the technological development of the cellular mobile phones

basically they can be divided into two main categories namely analogue and

digital cellular technologies. Each category has its own types. For example in

analogue we have like AMPS (Advanced Mobile Phone System). It was

developed by Bell Labs in the 1970s and first used commercially in the United

States in 1983. It operates in the 800 MHz band and became the world’s largest

cellular standard.19

19 http://www.privateline.com/PCS/wirelesstable.htm

However, after the 1980s there are more and more cellular

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mobile providers began to shift to digital system. And GSM (Global System for

Mobile) is considered the first digital cellular system.20

The principle used in cellular is called ‘frequency reuse’.

GSM is a digital

communication technology used by some carriers to provide PCS service. And the

other technologies besides GSM and AMPS are CDMA (Code Division Multiple

Access) and TDMA (Time Division Multiple Access).

II.2 The Basic Principles of Cellular Mobile Phone System

21 It is aimed to increase

the service to mobile phone’s subscribers. What is meant by frequently reuse is

using low powered mobiles and radio equipment in each site of cells, so that it

enables the same radio frequency to be reused in different cells. And it can

multiply the calling capacity without causing interference. It is greatly different

from the earlier mobile systems which used a high powered, centrally located

transmitter. And the frequency used by the mobile phones were not reused over a

wide area.22

All analogue and digital mobiles use a network of base stations and

antennas to cover a large area. If it is seen on a diagram the small place which is

covered by each base station appears like a cell in a honeycomb. That’s why it is

called cellular. The size of the cell varies from sixth tenths of a mile to thirty

miles in radius for cellular (1km to 50km).

23

20 http://www.comms.eee.strath.ac.uk/~gozalvez/gsm/gsm.html 21 http://www.privateline.com/Cellbasics/Cellbasics.html 22 http://www.privateline.com/Cellbasics/Cellbasics.html 23 http://www.privateline.com/PCS/HowPCS works.htm

In each cell was built radio base

station to handle the incoming signals from other cells.

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The Ericsson diagram below shows the macrocells, microcells and piccocells

work. Slow-moving subscribers such as those who are walking are handled within

microcells. While fast-moving subscribers for instance those who are driving or

on the public transports are handled within the macrocells. Piccocells are to

maintain subsribers of cellular phones who are in a building or in a closed place.

The advancement in dividing cells into several kinds has developed the quality of

receiving and sending voice.

Figure 1: Ericksson Diagram of macrocells, microcells and piccocells

(http://www.privateline.com/PCS/HowPCSworks.htm)

Figure 2: Cells

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(http://www.privateline.com/PCS/HowPCSworks.htm) The cells, geographical area where mobile radio communications in cellular radio

happen between a fixed base station (BS) and a number of roaming mobile stations (MSs).

Figure 3 (http://www.privateline.com/Cellbasics/Cellbasics.html)

The picture above shows how wireless technology work. Cell phones use low-

energy FM radio waves to transmit voice to the nearest antenna (in a cell) with the

local phone network. Then the call will go through either a regular phone line or

by radio signal to another cell phone, depending on whom we are calling. This

technology uses individual radio frequencies by dividing service areas into

different geographic zones. And these zones are called cells. Cells here can be as

small as Leeds University library or as large as London City. Usually there are

more cells in cities than in rural areas, because there are more people in cities than

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in rural areas. So, more people, more cells. And each has its own computer,

transmitter, receiver and directional antenna which are linked to MTSO or Mobile

Telephone Switching Offices.24 The power of the radio equipment in the base

station is fixed so that it covers only the particular cell. When a cellular phone is

switched on, the computer at the nearest base station senses its presence within the

cell and then the phone can transmit and receive messages from that position.25

II.3 Analogue vs Digital Cellular Phones

When a cell phone’ subscriber moves from one place to another, his/her call is

handed off by MTSO to the next cell site.

Cellular telephone systems can be ‘analogue’ or ‘digital’. Older systems like

AMPS, TACS, NMT are "analogue" and newer systems such as GSM and PCS

are "digital".26 The major difference is in how the audio signals, e.g. our voice, is

transmitted between the phone and base station. "Analogue" and "digital" refer to

this transmission mechanism. Probably just as audio cassettes versus CDs - audio

cassettes are analogue and CDs are digital.27

In either system, the audio at the microphone always starts out as a voltage

level that varies continuously over time. High frequencies (high pitch) cause rapid

changes and low frequencies cause slow changes. With analogue systems, the

audio is modulated directly onto a carrier. It has many similarities with FM radio

where the audio signal is translated to the RF signal. With digital systems, the

audio is converted to digitised samples at about 8000 samples per second or so.

24 http://www.cellularone.com/library/pages/history.html 25 Central Office of Information, Aspects of Britain. (London:1994).p. 49-50. 26 http://www.iit.edu/~diazrab/cell/analogueDigital.html

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The digital samples are numbers that represent the time-varying voltage level at

specific points in time. These samples (numbers) are now transmitted as 1s and

0s.28 At the other end, the samples are converted back to voltage levels and

"smoothed out" so that you get about the same audio signal. Some maybe lost, but

it may be unnoticeable - depending on how it is done. With analogue

transmissions, interference (RF noise or some other anomaly that affects the

transmitted signal) gets translated directly into the recovered signal - there is no

"check" that the signal makes sense. The neat thing about digital is that the 1s and

0s can not be easily confused or distorted during transmission, plus extra data is

typically included in the transmission to help detect and correct any errors.29

Digital technology offers better quality of sound, service and more security

for the customers and the capability to support services of the next generation.

30

There are three types of cellular handset or cellular phone, namely the car-phone

or mobile, the transportable and hand-portable.

Moreover, digital is more efficient in terms of its achievement in the network. An

operator could fit more information into each transmission. So, no wonder if there

are many cellular phones’ providers are converting their systems to digital now.

II.4 Cellular Equipment

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The car-phone or mobile is fitted into a vehicle and receives its power supply

directly from the vehicle’s battery. It is hands-free since it is voice-activated. This

27 Communication and Technology lecture, December 2000. 28 Technology and Communication lecture, December 2000. 29 http://www.iit.edu/~diazrab/cell/analogueDigital.html 30 http://www.wirelessadvisor.com/analog-cellular.cfm 31 Central Office of Information, Aspects of Britain. (London:1994).p. 53.

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enables a caller to use it without holding the handset. However, this device can

only be used in the vehicle.

The transportable phone is the same with the car-phone but it is designed as

an integral unit. It is equipped with detachable battery so that it can be used

outside the vehicle. However, it has a lower output if it is used outside the vehicle.

Hand-portables are the lightest cellular phones because they are equipped

with battery that is integrated with the handset. And the battery is rechargeable.

Therefore, the hand-portables cellular phones can be used inside or outside a

vehicle. Their power output is lower than the car-phones or transportable, so that

they can work best where network coverage is good, like in cities or other built-up

areas.32

- The problem of the previous technology of cellular mobile communication

system was the limited bandwidth. Because bandwidth allows information to

move effortlessly and transparently to where it is needed. The greater the

bandwidth, the richer the information we can move.

III. Conclusion

Based on the analysis, it can be concluded that:

- Wireless technology has come along way. And it will go further. With

increased competition, lower rates, smaller phones and larger coverage areas,

wireless service will challenge traditional phone service for our business.

32 Central Office of Information, Aspects of Britain. (London:1994).p.53

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- The invention of cellular mobile communications system has boosted the

development of the ‘wireless technology’. People can get connected any time

and any where.

- The combination of cellular phone and internet enable the cellular mobile

communication system maximaze its function as a wireless communication

device. Moreover with the more advanced technological development, the cost

of communication through cellular phones can be reduced and the size of the

hand set gets smaller, lighter and rich in features. What’s more the coverage

area becomes wider.

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REFERENCES

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December 2000. Reference Services, Central Office of Information (1994), Aspects of Britain:

Telecommunications, London: HMSO Publications Centre. Steele, Raymond (1992), Mobile Radio Communications (Ed). London: Pentech

Press Publishers. http://www.wave-guide.org/archives/waveguide_3/cellular-history.html. Accessed

on 05/12/00. http://www.privateline.com/PCS/HowPCSworks.htm. Accessed on 05/12/00. http://www.privateline.com/PCS/wirelesstable.htm. Accessed on 05/12/00. http://www.fcc.gov/wtb/cellular/celfctsh.html. Accessed on 21/11/00. http://www.dailynews.yahoo.com/h/zd/20001124/tc/bandwidth_is_a_blessing_1.h

tm. Accessed on 26/11/00. http://www.cellularone.com/pages/library/history/html. Accessed on 20/12/00. http://www.privateline.com/Cellbasics/Cellbasics.html. Accessed on 20/12/00. http://www.comms.eee.strath.ac.uk/~gozalvez/gsm/gsm.html. Accessed on

06/12/00. http://www.gallup.com/poll/releases/pr000426.asp. Accessed on 19/12/00. http://www.wirelessadvisor.com/Glossary.cfm. Accessed on 23/12/00. http://www.wirelessadvisor.com/analogue-cellular.cfm. Accessed on 23/12/00.