The Impact of Feeder Link Interference in Multiple Gateway Multibeam Satellite Systems

High throughput satellites rely on the reuse of spectrum across different beams. To this end, beams are synthesized by complex array fed reflectors. Multiuser techniques such as precoding can make viable an aggressive reuse of the spectrum, even to the point of facilitating the path towards full frequency reuse deployments. This entails a high demand on the feeder link, which needs to be provisioned by multiple gateways in order to accommodate all the throughput. As a consequence, spectrum needs to be also reused by the different gateway-to-satellite links, potentially causing inter-feeder link interference in addition to the user link multiple beam interference. This paper addresses jointly the interference in both user and feeder links by proposing two novel precoding techniques. An analysis is provided to account for the additional degradation coming from the co-channel interference in the feeder link.