Frequency reuse technique for a high data rate satellite communication

Abstract

Frequency reuse and data coding methods for use in a high data rate satellite communication system. The frequency reuse method provides for dual polarization and spatial reuse of transmit and receive beams to provide for a twelve-fold increase in the effective bandwidth and number of users that may be supported by the system. Transmit and receive antennas provide multiple, interleaved transmit and receive antenna beams. Digital input data at a source user terminal is coded and transmitted from a source user terminal on one of the plurality of receive antenna beams. The received data is demodulated and is routed so that it may be transmitted to a destination user terminal. The data is then remodulated, multiplexed, and transmitted to the destination user terminal on one of the plurality of transmit beams. The transmitted data is decoded at the destination user terminal to produce the output data. The input and output data processed by the system is digital, and the coding (concatenated coding forward error correction processing) is employed to reduce the sensitivity of communicated data to interference. The presently preferred encoding method comprises Reed-Solomon encoding input data, interleaving the encoded data, and convolutionally encoding the interleaved data and then time division multiplexing and modulating the data. The presently preferred decoding method comprises demodulating and demultiplexing received time division multiplexed data, Viterbi decoding the demultiplexed data, deinterleaving the Viterbi decoded data, and Reed-Solomon decoding the deinterleaved data to produce the output data. Other multiplexing schemes may alternatively be employed. The demodulating and remodulating steps regenerates a high quality digital data stream on the satellite that is communicated to the destination terminal to reduce the effects of uplink interference upon the downlink data stream.