Zone sharing transponder concept

Claim 1

An improved Space Division Multiple Access-Time Division Multiple Access Communications satellite system of the type which includes a switching matrix on-board the satellite for selectively interconnecting a plurality of communications receivers, each receiving incoming signals from a separate spotbeam antenna in view of its associated discrete geographical zone, to a plurality of transmitters each transmitting outgoing signals through a separate antenna in view of its associated discrete geographical zone, according to a predefined sequence, wherein the improvement comprises: a. input switching means on-board the satellite for alternately connecting a plurality of receive spot-beam antennas to a common receiver thereby enabling said receive antennas to share the same receiver; b. output switching means on-board the satellite for alternately connecting a plurality of transmit spot-beam antennas to a common transmitter thereby enabling said transmit antennas to share the same transmitter; c. a holding register on board the satellite having a capacity for storing and outputting an input code word corresponding to said input switching means and capacity for storing and outputting an output code word corresponding to said output switching means; d. timing control means on-board the satellite for producing pulsed timing signals on a periodic basis, each period representing a satellite time frame, said timing signals being for synchronizing said input switch and said output switch with said switching matrix; e. first decoding means on-board the satellite connected to receive said input code words outputted from said holding register and connected to said input switching means for decoding said input code word and causing the switch connection made by said input switching means to change in response to a change in said input code word; and f. second decoding means on-board the satellite connected to receive said output code words outputted from said holding register and connected to said output switching means for decoding said output code word and causing the switch connections made by said output switching meaNs to change in response to a change in said output code word.