Two-Stage Framework for Sensing Assisted Covert Communications

Abstract

In this work, we propose a two-stage integrated sensing and communication (ISAC) framework for exploiting the benefits of utilizing ISAC's detection capability in covert communications. Specifically, in the first stage a full-duplex transceiver Bob detects the presence of a warden Willie while performing uplink transmissions to another transceiver Alice. Then, in the second stage Bob helps Alice's covert downlink transmission via jamming as per his detection outcome in the first stage. We optimally design the covert ISAC system to maximize the formulated overall covert rate subject to a covertness constraint, an average power constraint at Bob, and an uplink rate requirement. As shown in our examinations, the proposed two-stage framework significantly outperforms a benchmark scheme without the detection function in terms of achieving a higher covert rate. This, for the first time, explicitly demonstrates the superiorities of using ISAC's detection function to enhance covert communications.