©1999 IEEE VESIT Student Branch Hits :
Webauthor : Saumitra M Das
|
|
|
|
SATELLITE PHONES The cellular telephony rewrote the way communications are done. Now, the advent of mobile satellite services is once again about to change how we communicate.Now, we need not be out of touch with anyone no matter where on Earth you are! Whether you are in the dense jungles of South Africa, or on the tip of the Mount Everest or holidaying away on the beaches of Hawaii, the need to be in constant communication in this highly competitive world will be satiated by the state of the art technology of the SATELLITE PHONES. These satellite phones are the cutting edge of how things in the next decade will be done.With this new technology any type of telephone transmission--voice, data, fax, or paging--will soon be able to reach its destination anywhere on the planet via satellite-based wireless personal communications networks. So, you can take your portable office consisting of a laptop interfaced to your satellite phone anywhere in the world. By providing global handheld service, mobile satellite services will bring a new dimension to global personal communications. Indeed, a NASA-commissioned study compared mobile satellite services with personal computers, in terms of their potential impact on both our professional and personal lives. The concept of mobile satellite services is not new. Ships, airplanes, and trucks have relied on geostationary satellites to provide mobile satellite services for years. Now, however, low cost orbit satellites will soon make mobile satellite services available for individuals using wireless and handheld telephones.The satellite services to be used will be based upon the technology used. The major companies in the fray like Iridium, Global Star and Inmarsat are investing into low-orbit earth satellites as well as geostationary satellites. The geostationary satellites which have an altitude of 35,900 km above the earth, while the low-earth orbit satellites are deployed some 700 km over the earth. This, in combination with recent advances in semiconductors, microprocessors, and other technologies, makes it possible to use a handheld telephone to provide Mobile satellite services. Unlike cellular telephone technology, where a user moves through cells, mobile satellite services rely on satellites moving overhead of a user. If a subscriber moves out of the beam of one satellite, an adjacent satellite will take over the call and hence, a network of satellites have to be maintained. The number of satellites in a network varies, depending on the design of the mobile satellite service. Moreover, the users of dual mode mobile satellite phones will be able to chose between satellite or cellular connections. Thus, mobile satellite services are designed to be complementary to landline and cellular telecommunications networks. The majority of calls will either originate or terminate over conventional communications hardware, which will add traffic--and revenue--to domestic networks. It’s flat rate, single billing charges and no long distance or roaming fees will make it more cost effective. Milind Nagda |
|
©1999 IEEE VESIT Student Branch Hits :
Webauthor : Saumitra M Das |