Use of a processing satellite for digital data transmission between low-cost earth terminals

A digital data transmission network consisting of thousands of small, low-cost user terminals and a fairly complex communication satellite is considered. Randomly timed data packets are transmitted by the user to the satellite where the signals are demodulated, processed, and retransmitted to ground. The low bandwidth efficiency of the uplink is compensated by extensive frequency reuse through use of a multiple-beam satellite antenna. Data readout from satellite buffer storage occurs at a lower continuous rate to provide a bandwidth-efficient downlink to the user. Thus, frequency reuse for the downlink need not be as extensive as the uplink, and fewer downlink antenna beams are required. It is predicted that advances in technology will make multiple-beam satellites with on-board signal processing feasible.