RIS-Assisted Integrated Sensing and Communication via Full-Duplex Cooperative NOMA

To improve the service quality for edge users, this paper proposes the full-duplex (FD) cooperative non-orthogonal multiple access (CNOMA) framework for a reconfigurable intelligent surface (RIS)-assisted integrated sensing and communication (ISAC) network. Specifically, OMA is integrated into CNOMA to mitigate substantial inter-cluster interference. Furthermore, we propose an optimization problem aimed at simultaneously maximizing the weighted sum rate and sensing power. This problem includes optimizing the power allocation of the near user in a cooperative system, the power allocation factors within each cluster, the beamforming matrix at the base station (BS) and the phase shift matrix at the RIS. To address this highly-coupled and non-convex problem, we propose an alternative optimization (AO) algorithm, where penalty and successive convex approximation (SCA) methods are employed. Simulation results validate the effectiveness of the proposed scheme, demonstrating significant performance gains compared to conventional NOMA and OMA benchmarks.