Joint Design of Phase Shift and Transceiver Beamforming in RIS-Assisted Full-Duplex ISAC System

Integrated Sensing and Communication (ISAC) is becoming increasingly important in next-generation wireless networks. This paper focuses on an ISAC system supported by a reconfigurable intelligent surface (RIS), where a full-duplex base station (BS) simultaneously performs uplink multi-user communication, downlink multi-user communication, and radar sensing tasks with the assistance of the RIS. To maximize the sum rate of all downlink and uplink users, an optimization problem is formulated, subject to multiple constraints, including target detection signal-to-interference-plus-noise ratio, self-interference, BS transmission power, user transmission power, and unit-modulus constraints of RIS reflection coefficients. To address the complex non-convex optimization problems, efficient solving algorithms are proposed, and their performance is validated through simulations. The results demonstrate that the RIS-assisted full-duplex ISAC (RAFD-ISAC) system significantly enhances both communication and sensing performance. The proposed joint beamforming and reflection design offers a novel solution for the deep integration of sensing and communication in next-generation networks.