Secrecy Energy Efficiency Maximization for UAV Enabled Communication Systems

Unmanned aerial vehicle (UAV) communication is recognized as a promising technology in next generation wireless communication system. As air-to-ground (A2G) communication is vulnerable to eavesdropping attacks by malicious ground adversaries, UAV communication systems face severe security challenges. This paper investigates the secrecy energy efficiency (SEE) maximization problem for UAV enabled communication systems. We aim to minimize energy consumptions required for secure communication via jointly optimizing scheduling, power allocation and UAV trajectory over a certain period of time. However, The formulated problem is non-convex and difficult to solve. To make the problem more tractable, we decompose it into three subproblems and propose an efficient iterative algorithm to obtain an appropriate solution. Simulation results show that compared with the benchmark schemes, our proposed method significantly improves the secrecy energy efficiency of UAV communication systems.