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Multicast Precoding for Multigateway Multibeam Satellite Systems With Feeder Link Interference

This paper studies the multigroup multicast precoding problem in frame-based multigateway multibeam satellite communications with feeder link interference. We formulate a sum rate maximization problem that incorporates the minimum signal-to-interference-and-noise-ratio requirement for each user, the sum power constraint at each gateway, as well as the per feed power constraints at the satellite. Both transparent payload and payload with on-board processing are considered. In the former case, we propose a centralized algorithm by employing the successive convex approximation (SCA) approach, which iteratively approximates the original nonconvex problem to a second-order cone program. Moreover, in order, for each gateway, to compute its precoding vector locally with local channel state information, we devise a decentralized algorithm by incorporating consensus alternating direction method of multipliers (ADMM) into the SCA framework. For the latter case, we devise a two-stage precoding scheme where, in the first stage, a leakage-based minimum mean-square-error scheme is employed to control the feeder link interference efficiently. In the subsequent second stage, we use the SCA-ADMM approach to deal with the user link interference while maximizing the sum rate. Finally, numerical results are presented to demonstrate the performance of the proposed schemes.