Joint Transmit and Receive Beamforming Design for Uplink RSMA Enabled Integrated Sensing and Communication Systems

This paper studies an uplink rate splitting multiple access (RSMA) enabled integrated sensing and communication (ISAC) system, where a radar-communication (RadCom) base station (BS) receives the signals from communication users (CUs) while simultaneously sensing the target. By utilizing the rate splitting (RS) paradigm to split the CU with better channel condition into two virtual CUs, the inter-user interference is mitigated substantially and a higher sensing performance is achieved with determinate communication performance requirements. Under this consideration, we jointly optimize the transmit and receive beamforming to maximize the radar signal-to-interference-plus-noise ratio (SINR) while ensuring to the CUs’ rate requirements as well as the transmit power constraints of BS and CUs. However, due to the coupled variables and non-convex constraints, the formulated problem is non-convex and difficult to solve. To tackle this problem, we propose an effective alternating optimization (AO) algorithm, specifically, in each iteration, the optimal transmit radar waveform is derived via the rank-1 guaranteed semidefinite relaxation (SDR). Simulation results are provided to validate the performance of our proposed design and it is shown that RSMA is effective and robust for suppressing interference.