RIS-Aided Multi-Beam Cooperative Transmission for Satellite-Terrestrial Communication

Achieving seamless connectivity is one of the key visions for sixth-generation (6G) wireless communication systems. Satellite communication (SatCom) system, especially the multisatellite cooperative communication, has become an indispensable part of space-air-ground integrated communication network due to its superior capability in providing wide area coverage. However, the performance of satellite-terrestrial communication is severely limited by high path loss. Reconfigurable Intelligent Surface (RIS) has been considered as a potential enabling technology in 6G to improve the service quality of various communication systems. In this paper, a RIS-aided multi-beam cooperative transmission scheme is proposed to boost the system performance of satellite-terrestrial communication. By optimizing the RIS reflection phase dynamically, the system capacity is considerably improved during the continuous service time of dual satellites. Based on the simulation results, we also point out the impact of the discrete phase optimization and RIS's inclination angle on the system performance considering the deployment of RIS in three-dimensional (3D) space.