ON-BOARD PROCESSING AND FUTURE SATELLITE-COMMUNICATIONS SERVICES

During the thirty year history of satellite communications there have been numerous changes due to technological advances. Nonetheless, there has been but one single dominant paradigm underlying the philosophy of communications satellites. That paradigm is referred to as the 'bent-pipe' geostationary satellite. There is now evidence that some of the latest technolog ical innovations will do more than merely improve methodologies and change techniques. There is the potential for a drastic change in the underlying paradigm. One element of this new paradigm is the concept of satellite constellations. Another element is on-board processing. The purpose of this article is to demonstrate that on-board processing can provide operational flexibility and system performance not available within the present paradigm; that there are no technological reasons for not implementing the current state-of-the-art technologies; and that the satellite communications paradigm is in the process of shifting from 'bent-pipe' geostationary satellites to intelligent satellite constellations. On-board processing is also an enabling technique for other associated advanced technologies such as multibeam antenna systems; high frequency transmission systems; baseband switching; and rain fade compensation. These advanced technologies are evaluated and recommendations regarding their implementation are presented.