Cooperative UAV Jammer for Enhancing Physical Layer Security: Robust Design for Jamming Power and Trajectory

An unmanned aerial vehicle (UAV)-aided network is becoming a promising application for the future wireless communication due to the flexible deployment and dominant line-of-sight channel. In this paper, we consider the UAV is operated as a cooperative jammer to enhance the physical layer security of the ground legitimated nodes in the presence of an eavesdropper (Eve). Furthermore, we assume that the UAV has imperfect information on the locations of the receiver and Eve due to GPS jamming and covert operation of Eve, respectively. With these uncertainties of the nodes' locations, we formulate a robust joint optimization problem of the UAV's jamming power and trajectory to maximize the average secrecy rate. To handle the non-convexity of the optimization problem, we propose an iterative suboptimal algorithm based on the block coordinate descent method. Simulation results present that the proposed algorithm has outstanding performance in terms of physical layer security compared to other benchmark methods.