Optimal Covert Age of Information for ARIS-Assisted Covert Communication System

In this letter, we investigate the problem of the covert age of information (CAoI) in short-packet covert communication assisted by aerial reconfigurable intelligent surfaces (ARIS). We analyze the detection performance at warden Willie and provide the expression for the system’s average CAoI. Then, through joint optimization of the three-dimensional (3D) hovering position of uncrewed aerial vehicle (UAV) and phase-shift matrix of reconfigurable intelligent surfaces (RIS), we propose the problem of minimizing average CAoI under covert constraints. To address this non-convex optimization problem, we decouple it into two sub-problems and introduce an iterative optimization algorithm to find suboptimal solutions. Simulation results demonstrate the superior performance of the proposed algorithm, showing that it achieves a smaller average CAoI compared to baseline schemes.