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GLOBAL MOBILE PERSONAL COMMUNICATION BY SATELLITE

S. M. Khabiruzzaman

Since the invention of telecommunication, no technology more than satellites has so enlarged the scope and reach of man’s communications. The field of satellite communication is expected to expand in the next decade from an $ 11 billion industry to a $ 30 billion one. Despite the development of fiber optic cables, satellites still accommodate 60% of overseas communications traffic.

Historical Background of Satellite.

The concept of a global telecommunication system based on geosynchronous satellites was first put forward in an article for the British Magazine "Wireless World" in May 1945 by the physicist and author Arthur C. Clarke. After that the USSR launched the first satellite "SPUTNIK" in 1957. In 1962 in launching the first operational

telecommunication service, transatlantic connections between Andover (U.S.A) and Pleumeur-Bodou (France) later Goonhilly (UK) through TELSTAR then RELAY, were established. Then in 1963, the first geostationary telecommunication satellite SYMCOM-3 with 300 Telephone circuits or one TV Channel was launched. In 1964 a multinational organization INTELSAT is created to launch, operate and maintain global telecommunications through satellites with 19 national administrations as initial signatories.

INTELSATS operation was started in 1965 with the launch of the first INTELSAT Satellite (INTELSAT 1 or Early Bird) in the frequency band 4/6 GHz. Due to requirement for larger satellites with increased capacity, INTELSAT and some other countries and satellite companies have so for launched a series of satellites in the geostationary orbit. At present INTELSAT VH-A is the largest and latest commercial communications Satellite in the geostationary orbit.

Satellite Systems in Orbit.

Satellite system were evaluated in three options.

i) An enhanced Geostationary Orbit (GSO) Satellite system, orbiting at 36,000 km (22,300 miles) with more powerful and larger antennas.

ii) An Intermediate Circular Orbit (ICO) Satellite system overlay with between 9 and 15 space craft orbiting at about 10,000-15,000 Km (6,200 - 9,400 miles),

iii) A Low Earth Orbit (LEO) Satellite system overlay comprising 48 operational, orbiting at about 1,800 km (1,125 miles)

The Satellite System Candidates

INTELSAT OVERVIEW

INTELSAT is the International Telecommunications Satellite organization of over 125 countries. It operates the global communications satellite system used by most of the countries around the world for nigh quality, reliable, international telecommunications services. A large number of these countries use INTELSAT satellites for

domestic public communications as well. Infect INTELSAT is the major provider of the worlds international voice, data communications and international TV transmissions.

In accordance with its charter, INTELSAT provides international public telecommunications services to all countries of the world (about 180) at the lowest possible cost. INTELSAT now extends to more than 1,700 earth stations to earth station communication links that compass the globe with 19 geostationary Satellites. This system carried more than 119,000 public switched network and more than 240 full - lime leases. Today, Very Small Aperture Terminals (VSATs) are a dynamic and important part of the telecommunications environment. INTELSAT VIs and VIIs are leading to the increased use of VSATs, IBS and internet particularly for business applications. 1NTELSAT operate in a competitive environment, Moreover, INTELSAT remains the dominant force in the international satellite communications.

ICO Satellite system

Inmarsat-P and some other companies have decided to provide global hand - held phone service with and Intermediate Circular Orbit (ICO) Satellite system. At present following four companies planned to operate ICO Satellite system.

Venture

Ellipse

Odyssey

AMSC

Jnmarsat - P

Number of Satellite

16

12

10

10

The service of Inmarsat-P will be provided by the year 1999-2000, as the best overall selection in terms of technology service, performance, cost and risk trade-offs.

INMARSAT-P ICO system characteristics

No of Satellites                                 10 or 12 operational

                                                        (2 planes x S or 3 planes x 4)

Orbit                                                 ICO, 10,355 km

Frequency Bands                             1.9 GHz/2.2 GHz

(mobile links)

Frequency Bands                             Ka band or C band

 (feeder links)

Beams                                             about 85

Capacity (system)                         4000 circuits per satellite

Outer Power                                 Around 500W RF Power

LEO based system

Low Earth Orbit satellite systems will soon be bringing the benefits of fast and economic telecommunications systems to a growing number of developing countries. It is estimated that the worldwide market for mobile satellite communications service will be more than 5 million subscribers in 2002, growing to more than 33 million in 2012.

At present, the phone service penetration in selected countries are as follows:

Country/Region                                                     Lines/100 Population

United States   58
Europe                                                                44

    Great Britain                                                    47
Italy                                                                      42
Spain                                                                    36

Asia Pacific                                                           18

    Hong Kong                                                        51
New Zealand                                                         47
Japan                                                                     46
Malaysia                                                                 13
China                                                                         3   
Bangladesh                                                             0.25

Although many countries have explosive growth in mobile communications and some have achieved relatively high penetration in mobile communications services, but large regions of the world are still stumbling to provide basic telecommunications services to their populations.

So Mobile Satellite Services (MSS), especially Low Earth Orbit (LEO) MSS systems will provide a cost effective solution to meet the basic need for communications services to vast areas not currently reached by telecommunications systems.

By the year 2000, three or four LEO global systems will be operating with one or two Asian regional systems. The following LEO Satellite systems will be operating for global systems.

Venture                                     No of Satellites


Iridium                                             66
Globalstar                                         48
Teledesic                                         840
Aries/ECCO                                     48

Globalstar and Iridium got their licenses to operate the systems.

Beginning in 2000, Globalstar will provide the commercial alternative for voice and data as part of the basic telecommunications services to many rural areas in the Asia-Pacific region. Because of its ability to provide inexpensive service to vast area, Globalstar and other MSS systems will provide telecom services in the area of former Soviet Union, China and Africa as well as Southern and Central Asia.

The rates for the Globalstar service will be similar to those of terrestrial cellular systems. So Asia-Pacific regional nations must provide a flexible regulatory policy and a conductive business environment to ensure LEO based MSS effectively and hilly.

To provide the LEO-based MSS to be successful, every regional governments must take the following changes.

  • To develop the LEO system MSS, each country need necessary allocation of L-band and S-band for the system with out interference from existing systems.
  • A regional LEO MSS policy should ensure that such a service is provided as a free market commodity, driven by demand and regulated by a simple set of rules.
  • Each country should allow flexible operational rules for introduction of the latest technologies.

Reference

1. TEL - ASIA-95

2. Telecommunications by Satellite TELESPACE


Engr S. M. Khabiruzzaman, Director, Satellite earth station project was born in 1947. He received hLc degree in B. Sc. Engg. (Electrical) in 1970 from B UET He was the Honorary Secretary of Dhaka Centre of Institution Engineers. Currently he is the Vice-President of Bangladesh Civil Service (Telecom) Samiiy, He is the author of a book "Unnasattarer Gano Abbhuthan."