NEW DELHI, DEC 29: If internet can draw the world to a desk top, satellite networking promises to revolutionise wireless telephony and confine the globe in a palm sized hand set.Whether on the top of Everest or in the middle of Sahara, or the remote villages of India, all one would need to connect elsewhere on earth would be a number with satellite networks and a handset.With mobile satellite service a reality and more and more groups working to improve the standard of telecommunications, a new society is in the making thanks to technology and the exploring spirit of man."We worked many hours, building satellites. Seven days a week, three shifts a day, week ends and holidays, so there is a lot of personal sacrifice involved, sure it has turned fruitful," says Kevin Zanellato, production manager of Motorola, the primary contractor of Iridium, a unique satellite network cenceptualised in 1987 to make global wireless communication a reality.Within ten years from then, the first satellite was launchedfrom California last year and by September 1998 a fully operational constellation of Iridium satellites were in the earth's orbit changing the very concept of communication.The Iridium network has 66 satellites orbiting earth in six planes with 11 in each plane. They operate approximately 780 kms above the earth in what is called Low Earth Orbit (LEO).Each satellite weighs about 700 kg and has a life span of five to eight years with a capability of transmitting 2.4 kilobytes per second.It can transmit voice and data in digital form with the Iridium's global mobile personal communication system offering fax and pager services to any corner in the world."Instead of one vehicle as in a traditional satellite programme, our attention was focused on developing many such satellites to influence a cost effective design at a low unit cost," says Andrew Feller, an engineer working with the project since 1992."Though satellites were used in telecommunication for the last three decades, the concept andvalue has changed with the invention of Iridium system, driven by an eventually radical thinking of satellite network architecture," says Feller.The technology has by now advanced so much that similar work can be carried out by three to four geostationary earth orbit satellites which are placed 36,000 kms above.Iridium satellites work differently from the geo-stationary ones in two ways and have an advantage over them: "first they are close enough to receive the hand held phone or a pager; and second, they act like cellular towers in the sky where wireless signals can move overhead instead of through ground based cells," says T K Sreedharan, the technical vice president of Iridium India Ltd.But communication experts say, geo-stationary satellites pose a major threat to Low Earth Orbit (LEO) satellites like Iridium as the former are much advanced in technology and would enable mobile phone service at a lower cost.However, Iridium engineers say they being the pioneers in providing global roamingfacility to cellular phone users, they consider the other satellites as a welcome step to boost competition."With others joining the mobile satellites service, the competition will increase which will result in high growth. But I feel the 18-24 months edge over them will confer a market leader status to us," says Jaydev Raja, chief of Iridium India.By investing 70 million US Dollar in the dream project, India enjoys a proud position in the Iridium LCC Inc. With the South Asian gateway being located at Dighi, near Pune bringing the whole of the sub-continent in its ambit.The Pune gateway is one among 15 in the world. These are ground stations that interface satellite system with the subscribers hand sets. They maintain a database and monitor subscribers billing and settlement of other technically related matters.They also offer 24-hour global customer care in 13 languages world over to facilitate easy and free roaming. So far this unique facility was limited to few stations and not used in cellulartelephony.The subscribers are allotted one permanent phone number and callers can reach one without knowing where that person is. Unlike the cellular system and the other terrestrial mode of telecommunication where it is not possible to establish contact if the whereabouts of the other person are not known, says a senior official.A subscriber handset costs about Rs two lakh in India and serves dual purpose : as cellular and satellite phones. While receiving and sending call, its antenna will connect the signals to the nearest satellite."The entire calling and dialing process takes only 15 seconds. As intersatellite link and transmission is possible the call is directed quickly," says Sreedharan."As each subscriber is given separate frequencies to operate, the signals will not overlap. The system employs highly sophisticated frequency and time division multiple access (FDMA and TDMA), he says.As the technology boom is ushered in, people can only look forward to top-of-the line facilities and atcompetitive price.
