Satellite on-board digital signal processing (DSP) offers the potential for significantly improved performance in certain satellite communications system scenarios in terms of system capacity and link quality. On-board DSP functions include digital beamforming, frequency multiplexing and demultiplexing, interference suppression, signal level control and, in a regenerative system, modems. The paper reviews the status of DSP in communications satellite payloads, focusing on the system advantages, some basic algorithms, and application specific IC implementation issues. As a specific illustrative example an advanced land mobile system is described which features digital beamforming and associated digital signal processing to achieve significant gains in power efficiency (and hence capacity), frequency reuse and flexibility to respond to changing traffic scenarios.
