Joint Secure and Covert Beamforming Design in Dual-Functional Radar-Communication Systems

Integrated sensing and communication (ISAC) has been recognized as a promising technique for the next generation wireless network. In this paper, we investigate the joint beamforming design from the perspective of the channel capacity based secure communication and the low probability detection based covert communication in the dual-functional radar-communication (DFRC) system. Specifically, the adversary is capable of both wiretapping and detection towards different legitimate users. In order to guarantee the security of both aspects simultaneously, we maximize the secrecy rate under the predefined level of the Kullback-Leibler (KL) divergence, covert rate and sensing metric, i.e., signal-to-clutter-plus-noise ratio (SCNR) of the echo signal. To deal with the proposed non-convex problem, we develop the semi-definite relaxation and quadratically constrained quadratic program (SDR-QCQP) based solution to implement the secure and covert beamforming design, where the initialization is implemented by the QCQP based on the feasible point pursuit (FPP) framework. Simulation results demonstrate the superiority and robustness of proposed algorithms under various parameter settings.