Robust 3D Trajectory Optimization for Secure UAV-Ground Communications

The utilization of UAV may suffer severe security problems due to the inherent characteristics of wireless air-to-ground (A2G) channels. To this end, researchers have drawn much attention on utilizing physical layer security (PLS) techniques to maintain secrecy data transmission in UAV enabled networks. Different from previous works, we jointly optimize user scheduling strategy, signal transmission power and 3D flying trajectory of the UAV to maximize the minimum system secrecy rate by considering UAV position and an eavesdropper with partial location information simultaneously. Because the formulated problem is intractable and non-convex, we in this paper develop an iteration approach to solve the problem based on the successive convex approximation (SCA) method. Finally, experimental results are further derived to validate the performance gains of our scheme.