This letter 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.

中文翻译：

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通过频谱共享进行协作干扰以实现安全的无人机通信

这封信调查了无人机 (UAV) 通信网络中的物理层安全问题。具体来说，两架无人机通过共享相同的频谱将机密信息传输到指定的地面目的地，而地面窃听者则试图窃听机密信息。在所考虑的场景中，虽然频谱共享引起的相互干扰可能会降低频谱效率，但也可以减轻窃听效应，因为这两种无人机本质上充当了彼此的合作干扰器。受此启发，设计了合作策略以打击窃听，从而最大限度地提高系统保密率。为此，提出了一种迭代算法来联合优化两种无人机的轨迹和发射功率。