Energy-Efficient Covert Communication With the Aid of Aerial Reconfigurable Intelligent Surface

In this letter, a novel aerial reconfigurable intelligent surface (ARIS) assisted covert communication framework is proposed, where RIS is mounted on unmanned aerial vehicle (UAV) to enhance the covert performance of ground transceivers in the presence of a warden. The detection performance of warden is first analyzed, and then a covert energy efficiency (CEE) maiximization problem is formulated by jointly optimizing power control, passive beamforming, and UAV trajectory. To solve the non-convex problem, an algorithm based on alternating optimization is devised to achieve the suboptimal solution. Numerical evaluations show that the proposed scheme has a larger CEE gain than the scheme without RIS under the condition of more reflecting elements. Moreover, the proposed scheme can achieve near-same covertness performance at a lower energy consumption cost compared with covert transmission rate maximization scheme.