3-D Successive-Hover-and-Fly With Power Allocation for UAV Covert Communications

Abstract

This letter addresses the scenario where uncrewed aerial vehicles (UAVs) perform covert transmission in three-dimensional (3D) space against ground Willie (GW). Aiming to maximize the minimum throughput among ground users (GUs) while ensuring fairness, we first derive the UAV transmit power subject to covertness constraints under GW position uncertainty. Building upon the successive-hover-and-fly (SHF) structure, we incorporate the UAV’s vertical dimension to transform the original 3D continuous trajectory into a finite set of connected discrete waypoints. Accordingly, a joint trajectory design and power allocation problem is formulated based on the transformed trajectory. Ultimately, a successive convex approximation technique is leveraged to convexify the problem, which is then efficiently solved via an iterative algorithm based on the ellipsoid method. Simulation results demonstrate that the proposed scheme significantly outperforms traditional benchmarks.