Robust Covert and Secure Transmission for ISAC System With Transceiver Hardware Impairments

In integrated sensing and communication (ISAC) systems, communication signals can easily be wiretapped by targets (potential eavesdroppers) or detected by wardens. Different from previous works that address a single security problem, we investigate a covert and secure beamforming design in the ISAC system to address this issue. Meanwhile, we also consider the hardware impairments (HWI) of transceiver, the angle and distance estimation errors of the eavesdroppers, and the imperfect warden channel. We formulate a secure beamforming optimization problem under sensing integrated sidelobe to mainlobe ratio (ISMR), communication rate, and covert communication constraints. To solve the non-convex optimization problem, we adopt semidefinite relaxation (SDR) and S-procedure techniques to transform it into a convex problem and solve it. The simulation results demonstrate the effectiveness of the designed scheme and reveal a trade-off between the communication and sensing performance of the system.