Channel and Interference adaptive SATCOM Digital beam-former

ABSTRACT: Digital beamforming is a key to maximum bandwidth utilization and flexibility for communication satellites. Adaptive beamforming further enhances this flexibility by more effectively removing interferers in the spatial domain. However, adaptive beamforming doesn't account for frequency differences in interferers, and may be difficult to implement for varying beam-bandwidths. Adding channelization before the beamformer and implementing the adaptive beamformer on a subchannel level resolves these issues. By making the adaptive beamformer work on a beam-subchannel basis, the beamformer processing resources can be easily assigned to beams ranging from a few kHz of bandwidth to hundreds of MHz. Additionally, the beamformer can adapt more effectively, since interferers are optimally nulled within each subchannel. This SBIR focuses on verifying the effectiveness of adaptive beamforming on a subchannel level, using polyphase filter banks for preprocessing. The research compares this approach with a more traditional approach using Digital Down Conversion (DDC) through performance simulations. It also evaluates the feasibility of implementation on SEAKR's advanced onboard processing hardware systems. Advanced processing systems, rapid signal processing design methodology, channelizer development experience, and knowledge of adaptive beamforming algorithms and implementations make SEAKR an ideal choice for performing this work. BENEFIT: Benefits of this research include improved bandwidth utilization and flexibility for communication satellites, improved response to atmospheric effects, and reduction of interference in the spatial domain. Additionally, the techniques proposed here enable practical implementation of sophisticated, high performance adaptive beamforming on existing onboard processing hardware. Commercialization opportunities are many, and include the WGS mission, the space platforms used by Intelsat and Inmarsat, among others. Commercial satellites have used RF beamforming for many years, and are beginning to move to more flexible beamforming approaches, as the desire for better bandwidth reuse drives system performance and flexibility.