Covert Communication Against UAV Surveillance via Integrated Sensing and Communication System

This paper proposes a covert transmission scheme assisted by the integrated sensing and communication technique against the surveillance of a mobile unmanned aerial vehicle (UAV). Specifically, the transmitter attempts to transmit covert information to the legitimate receiver, while disturbing the detection of the warden UAV by sending artificial noise (AN). By utilizing the reflected AN, we track the UAV's position and velocity using the extended Kalman filter. To maximize the covert rate, we jointly design the beamforming vectors of AN and covert information signal while considering constraints on covertness, tracking mean squared error (MSE), and transmit power. Then, we solve the beamforming design problem by using the semidefinite relaxation and the Charnes-Cooper transform. Numerical results show that our proposed scheme can efficiently enhance the covert rate in comparison with the baseline schemes, demonstrating the superiority of integrating sensing into covert communications. Furthermore, we reveal the impacts of the covert coefficient and the maximum tracking MSE on the covert rate.