Secure UAV Communications Under Uncertain Eavesdroppers Locations

Benefiting from the merits of low cost and high mobility, Unmanned aerial vehicle (UAV) enabled communications have recently drawn considerable attentions. In this paper, we consider the UAV-enabled physical-layer secure communications. Specifically, we consider a UAV-ground communication systems with multiple eavesdroppers whose locations are not perfectly known and are assumed to follow Gaussian distribution. An outage probability-constrained average secrecy rate maximization (ASRM) problem is formulated by jointly optimizing the trajectory and the transmit power of the UAV over a given flight duration. The ASRM problem is challenging due to the probabilistic constraints. To circumvent the difficulty, we employ a safe approximation approach and the successive convex optimization method to find a tractable solution to the ASRM problem. The effectiveness and robustness of the proposed design are demonstrated through simulations.