Multibeam, digitally modulated, time division, switched satellite communications system

摘要

The present invention relates to a multibeam, digitally modulated, time division switched communication system especially for use with a satellite repeater wherein separate up-link and down-link signals are transmitted between each of a plurality of ground station areas and the repeater using space diversity techniques. The frequency band of each up- link signal is split to include at least two frequency multiplexed channels, each channel being separated at the repeater and independently switched at baseband frequencies through a repeater switching network comprising at least two matrix switches for retransmission on the appropriate down-link signal. Synchronizing and clock recovery procedures are used to enable both the clock at each ground terminal station within each ground station area to be synchronized with a master clock at the repeater, and the corresponding bits and subframes within an information frame to arrive in synchronism at the repeater to permit simultaneous switching of all up-link channels through the repeater switching network. The repeater switching network is controlled from the ground terminal stations by control signals included in each up-link subframe, the control signals determining for its associated down-link channel which synchronized up-link channel from another ground station area is to be connected to the associated down-link channel.