R-SACE: RIS-Enabled Sensing-Aided Communication Enhancement in ISAC Systems

Integrated sensing and communication (ISAC) and reconfigurable intelligent surface (RIS) are two critical enablers for sixth-generation (6G) communication systems. Sensing-aided communication enhancement (SACE) is one of the foreseeable scenarios of ISAC. This paper focuses on a RIS-assisted SACE (R-SACE) mechanism where the base station (BS) acts as a sensor and communicator. In particular, the RIS and the sensing at the BS assist in suppressing harmful direct interference and meanwhile reconstructing another feasible communication link. The average achievable capacity maximization problem of the RIS-assisted communication link is investigated by jointly optimizing the time resource allocation within a coherent ISAC time frame and the reflecting recoding of the RIS under the constraints of sensing performance and interference. Alternating algorithm (AO) and particle swarm optimization (PSO) methods are utilized to solve the above optimization problem. Simulation results validate the performance gains of the proposed R-SACE mechanism in suppressing interference and enhancing average achievable capacity.