Performance study of multiuser interference mitigation schemes for hybrid broadband multibeam satellite architectures

As the demand for higher throughput satellites increases, multibeam architectures with smaller beam spots are becoming common place. If the same frequency is strongly reused, the resulting interference when serving simultaneously many users requires some sort of pre or post-cancelation process. This article focuses on precoding and multiuser detection schemes for multibeam satellites, comparing hybrid on-board on-ground beamforming techniques with fully ground-based beamforming. Both techniques rely on the exchange of radiating element signals between the satellite and the corresponding gateway but, in the latter case, the interference mitigation process acts on all the radiating signals instead of the user beams directly, with the corresponding extra degrees of freedom for those cases for which the number of radiating elements is higher than the number of user beams. The analysis carried out in this study has shown that the potential advantage of ground-based beamforming may exceed 20% of the total throughput.