Rate-Splitting Multiple Access Based on Spectrum Sharing for Integrated Satellite-Terrestrial Network

Abstract

To provide seamless communication service, the integrated satellite-terrestrial network (ISTN) has become the trend of communication development, where terrestrial terminals and satellite terminals share the same spectrum resources. Meanwhile, rate-splitting multiple access (RSMA) has recently emerged for flexible multiple access and robust interference management. Based on the two promising technologies, spectrum sharing and RSMA, we design two coordinated multiple access schemes in overlay and underlay spectrum sharing modes for ISTN. Furthermore, we consider the quality of service rate requirements and formulate joint optimization problems to maximize the weighted sum rate. To solve the non-convex optimization problems, an improved alternating optimization algorithm based on weighted minimum mean square error is proposed. Simulation results verify that the proposed schemes have significant performance gains compared with various baseline schemes.