FLEXIBLE ALL-DIGITAL MULTI-BEAM TRANSPONDER FOR SATELLITE COMMUNICATIONS

This Phase I SBIR proposal defines and architects an all-digital, multi-beam transponder for satellite communications, the ADMBT. The transponder architecture consists of flexible, digital processing components to perform all required signal processing operations.The ADMBT architecture receives satellite channels using a multiple antenna array and downconverts the channels to intermediate frequencies for high-rate, wide bandwidth digitization. The digitized data is channelized to a comon bandwidth and then partial bandwidth synthesized to the bandwidths needed for each of the signals-of-interest across multiple antennas. The SOI antenna vectors are then independently processed using either fixed or adaptive beamforming algorithms to produce the desired baseband SOIs. Post-beamforming, an on-board baseband processor is available to retune, reformat, or restructure the incoming SOIs for retransmission. The output SOIs are spatially beamformed for transmission using a-priori, conjugate, or otimal retro-directive beamforming weights. The multi-antenna spatial SOI data is then partial bandwidth channelized, combined with other overlapping and non-overlapping SOI cells, and synthesized into appropriate digital IF channels. To complete the process, the wide bandwidth digital IF channels are converted to analog, upconverted to the transmission frequency, and amplified for transmission.