Joint Beamforming and Reflection Design for RIS-Aided ISAC Systems

This paper investigates a sensing-centric beamforming design method for the integrated sensing and communication (ISAC) system aided by reconfigurable intelligent surface (RIS). The proposed framework addresses the critical challenge of spectrum efficiency enhancement through simultaneous sensing and data transmission. By exploiting the RIS’s ability to create virtual links through reflective elements, enhanced system performance is achieved. To maximize the detection probability, we formulate a joint optimization problem, which guarantees minimum sum-rate requirements for downlink users. The optimization involves the simultaneous design of transmit beamforming vectors and RIS phase shift matrices. Simulation results validate the effectiveness of ourmethod, demonstrating significant performance gains over conventional RIS-free ISAC systems in terms of both sensing accuracy and communication reliability.