Beamforming Optimization for Multiuser ISAC With Transceiver Hardware Impairments

In this paper, we investigate a multiuser integrated sensing and communication (ISAC) system with hardware im-pairments at both the base station (BS) transceiver and the users. Specifically, by considering the impact of hardware impairments, we optimize the transmit and receive beamforming at the ISAC BS to maximize the radar output signal-to-interference-plus-noise ratio (SINR) for sensing, under both point and extended target scenarios, subject to the constraints of communication requirement and power limitation. For both scenarios, we first find closed-form optimal radar receive beamforming and then obtain equivalent reformulations with respect to the transmit beamforming. Subsequently, for the resulting problems, a globally optimal solution is obtained for the point target scenario and an iterative solution is proposed for the extended target scenario. Finally, the effectiveness of the proposed methods is evaluated via simulation results.