Cooperative Jamming via Spectrum Sharing for Secure UAV Communications

This paper investigates the physical layer security issue in unmanned aerial vehicle (UAV) communication networks. Specifically, two UAVs transmit confidential messages to their specified ground destinations by sharing the same spectrum, while a ground eavesdropper attempts to wiretap the confidential messages. In the considered scenario, although mutual interferences arising from spectrum sharing may lower the spectral efficiency, the overhearing effect may also be alleviated as these two UAVs inherently act as cooperative jammers for each other. Motivated by this, a cooperation strategy is designed to combat eavesdropping, so that the system secrecy rate can be maximized. To this end, an iterative algorithm is proposed to jointly optimize the trajectory and transmit power of both UAVs. Simulations demonstrate that our proposed scheme can achieve significant secrecy rate gain in comparison with the benchmarks.