Covert Transmission via Integrated Sensing and Communication Systems

Integrated Sensing and Communication (ISAC) Systems, which can support simultaneous information transmission and target detection, have been regarded as promising solutions for various emerging wireless network applications. In this work, a covert transmission system with the aid of the ISAC technique is proposed, where the radar intends to sense a target and send message to legitimate users covertly against the warden's surveillance with either perfect or imperfect channel state information (CSI) at the warden. We formulate a beamforming optimization problem for the dual-function signal used for sensing and communication to maximize the covert throughput, subject to a covertness constraint, a maximum transmit power constraint, and a radar detection constraint. We then determine the sufficient conditions under which the covert beamforming design problem can be solved by semidefinite relaxation (SDR). Numerical results show that the proposed covert ISAC system can guarantee covert transmission while ensuring a certain level of sensing performance, and there exists a performance trade-off between the considered radar detection and covert transmission.