Covert Communications for RIS Assisted Systems With AAV Based Cognitive Jamming

In this study, a reconfigurable intelligent surface (RIS) assisted covert communication system with an autonomous aerial vehicle (AAV) based cognitive jamming is investigated. Specifically, the RIS is mounted on the AAV to assist the information transmission from the source to the destination. Simultaneously, the AAV could act as a cognitive jammer to interfere with the warden's detection by dynamically transmitting jamming signals according to the received ones. Under some certain covert constraints, an optimization problem is formulated by jointly optimizing both the transmit and jamming powers, and the RIS reflective phase shifts to maximize the transmission capacity. Numerical results demonstrate that adopting both cognitive cooperative jamming and RIS could enhance the transmission capacity under stringent covert constraints.