Flexible Position Antenna Enabled Resource Optimization for UAV Covert Communication

As a novel technology in recent years, the movable antenna (MA) array can effectively address the problem that the traditional fixed-position antenna (FPA) array is unable to use the spatial freedom degree well, thereby obtaining the higher covert communication capacity in the unmanned aerial vehicle (UAV) covert communication system. In this paper, we propose a resource optimization method for the UAV covert communication enabled by the flexible position antenna. Firstly, we formulate an optimization problem aimed at maximizing the average covert communication rate of all users in all time slots under the constraints about the three variables to be optimized, which are transmitting beamforming, trajectory, and MA position. Then, we propose three subproblems to optimize the three variables, respectively. And for the optimization of the MA position, we adopt the projected gradient ascent (PGA) method to obtain its final solution. Finally, we propose an alternate optimization (AO) algorithm to solve the proposed optimization problem. Simulation results demonstrate that the MA array outperforms the FPA array due to its superior flexibility, and the proposed method has better covert communication performance than all benchmarks.