Communication Satellite Onboard Processing

The primary purpose of communication satellites is to receive signals from one or more sources and relay them to intended recipients. To accomplish this many communication satellites incorporate one or more “translating repeaters” or “transponders” which simply amplify and frequency-translate a band of frequencies. However, digital circuit and signal processing technology has progressed to the point that it is feasible and advantageous to implement more powerful processing functions on-board the satellite. On-board processing can enable systems to: make more effective use of power and bandwidth; improve multiple access performance; reject interference; and provide richer interconnectivity. On-board techniques include: beam switching; adaptive antennas; demodulation-remodulation; access control; and packet switching. This article will discuss each of the techniques and give a number of system application examples. Keywords: bandwidth-limited; beam switching; bent pipe; demodulation-remodulation; despreading; multiple access; multiple beams; on-board processing; packet switching; power-limited; satellite communication; translating repeater