Robust Rate-Matching Framework for Multibeam Satellite Communications with Phase Perturbations

Multibeam satellite communications (SATCOM) is emerging as one of the key technologies to provide broadband services over a wide area with ubiquitous connectivity. Within the broad coverage for the multibeam SATCOM, the traffic demands of users are extremely heterogeneous due to various geological conditions and user distribution. Inspired by this, we propose a robust and powerful rate-matching (RM) framework to minimize the difference between traffic demands and offered rates based on rate-splitting multiple access (RSMA). Moreover, channel phase perturbations caused by both channel estimation and feedback errors are considered to capture realistic multibeam SATCOM scenarios. To tackle the non-convexity of the RSMA-based RM problem under phase perturbations, we convert the formulated problem into a tractable convex form via the successive convex approximation method and present an efficient algorithm to solve the RM problem. Numerical results show the superiority of the proposed RSMA-based scheme, compared with the various benchmark schemes, in terms of non-uniform traffic demand fulfillment and phase perturbation robustness.