UAV-enabled Secure Communication with Finite Blocklength

In the finite blocklength scenario, which is suitable for practical applications, a method of maximizing the average effective secrecy rate (AESR) is proposed for a UAV-enabled secure communication by optimizing the UAV's trajectory and transmit power subject to the UAV's mobility constraints and transmit power constraints. To address the formulated non-convex optimization problem, it is first decomposed into two non-convex subproblems. Then the two subproblems are converted respectively into two convex subproblems via the first-order approximation. Finally, an alternating iteration algorithm is developed by solving the two subproblems iteratively based on successive convex approximation (SCA) technique. Numerical results show that our proposed scheme can achieve a 6% to 13% improvement on the AESR performance compared with the benchmark schemes.