Interference and Channel Allocation Problems Associated with Orbiting Satellite Communication Relays

The use of active and passive relays is considered for application to long-distance global trunk communication, with particular emphasis on economic utilization of the media from the traffic capacity viewpoint. Active and passive techniques are compared with regard to power requirements, coverage, mutual interference, and ability to exploit wide-band modulation systems to reduce interference. With the emphasis on microwave transmission, narrow beamwidths, and a multiplicity of relays, channel allocations of the future will necessarily be determined by spatial considerations, in addition to specifying frequency bands. Examples with typical global paths and assumed active and passive systems are illustrated. It is concluded that, although a great increase in transmission capacity is forecast with the new techniques, a much broader scope of coordination will be necessary to control interference.