| 摘要 |
A multibeam communications satellite has direct links with at least one othe r satellite. The satellite's repeater operates in the bent-pipe mode and can provide serv ice to users independent of signal content, format and protocol. Each incoming electromag netic (radio) beam received by the satellite contains at least one channel of info rmation, and each channel is divisible into subchannels. Naturally, each subchannel is of a bandwidth which is less than the bandwidth of the channel from which the subchannel wa s derived. The other satellite has outgoing beams that complement the first satellites incoming beams. Generally, both satellites have processors on board designed to inter beam-switch at the subchannel level. (However, a description is given also of an instanc e where one or the other satellites may not have subchannelizing capability and limited use may be made of the invention). The satellites are linked by an intersatellite link carrying information on a channel consisting of subchannels constituted from several incoming channels. Therefore, an outgoing beam from the second satellite can contain a channel having information combined from several incoming channels to the first sate llite and the channel information on any incoming electromagnetic (radio) beam can be deli vered at the subchannel level to several output beams from the second satellite. The system can operate in a broadcast mode whereby information at the subchannel level can be distributed simultaneously (i.e. in parallel) to several outgoing electromag netic (radio) beams. The intersatellite link is treated as any other beam (incoming or out going, as the case may be), although its operating wavelength may be different from the op erating wavelengths of the beams having terrestrial origin or destination. For examp le, the intersatellite link could be at microwave, optical or some other suitable fr equency. The basic concept may be extended to a system supporting multiple intersatellite links, e.g. links in both directions between the two satellites or, in some circumstance s, among a constellation of more than two satellites.
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