Low-Complexity Grouping Precoding Based on RSMA for Multibeam Satellite System (Invited Paper)

Multibeam satellite system can provide seamless information service with high spectrum efficiency (SE). However, adjacent beams will cause severe inter-beam interference due to the reuse of spectrum resources in each beam. The existing interference management schemes regard multibeam satellite system as terrestrial multi-antenna system, and then apply precoding technology to mitigate inter-beam interference, which neglects the characteristics of beam gain attenuation. Meanwhile, the traditional precoding technology for all users will significantly challenge satellites with limited computational resources. Motivated by this, we design a low-complexity grouping precoding (GP) scheme to simultaneously consider beam gain and complexity. Combined with the promising rate-splitting multiple access (RSMA), we further maximize the weighted sum rate (WSR). Then, an alternating optimization algorithm is proposed. Simulation shows that the proposed GP scheme based on RSMA has higher WSR and lower computational complexity than other baseline access modes.