Unmanned aerial vehicles (UAVs) have attracted a lot of research attention because of their high mobility and low cost in serving as temporary aerial base stations (BSs) and providing high data rates for next-generation communication networks. To protect user privacy while avoiding detection by a warden, we investigate a jammer-aided UAV covert communication system, which aims to maximize the user’s covert rate with optimized transmit and jamming power. The UAV is equipped with multi-antennas to serve multi-users simultaneously and enhance the Quality of Service. By considering the general composite fading and shadowing channel models, we derive the exact probability density (PDF) and cumulative distribution functions (CDF) of the signal-to-interference-plus-noise ratio (SINR). The obtained PDF and CDF are used to derive the closed-form expressions for detection error probability and covert rate. Furthermore, the covert rate maximization problem is formulated as a Nash bargaining game, and the Nash bargaining solution (NBS) is introduced to investigate the negotiation among users. To solve the NBS, we propose two algorithms, i.e., particle swarm optimization-based and joint two-stage power allocation algorithms, to achieve covertness and high data rates under the warden’s optimal detection threshold. All formulated problems are proven to be convex, and the complexity is analyzed. The numerical results are presented to verify the theoretical performance analysis and show the effectiveness and success of achieving the covert communication of our algorithms.

中文翻译：

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干扰器辅助多天线无人机隐蔽通信性能分析与优化


无人机（UAV）因其高机动性和低成本作为临时空中基站（BS）并为下一代通信网络提供高数据速率而引起了广泛的研究关注。为了保护用户隐私，同时避免被看守发现，我们研究了一种干扰机辅助的无人机隐蔽通信系统，该系统旨在通过优化的传输和干扰功率来最大化用户的隐蔽率。无人机配备多天线，可同时为多个用户提供服务，提高服务质量。通过考虑一般的复合衰落和阴影信道模型，我们推导了信号与干扰加噪声比 (SINR) 的精确概率密度 (PDF) 和累积分布函数 (CDF)。获得的PDF和CDF用于推导检测错误概率和隐蔽率的封闭式表达式。此外，将隐蔽率最大化问题表述为纳什讨价还价博弈，并引入纳什讨价还价解决方案（NBS）来研究用户之间的协商。为了解决NBS问题，我们提出了两种算法，即基于粒子群优化的算法和联合两级功率分配算法，以在典狱长的最佳检测阈值下实现隐蔽性和高数据速率。所有表述的问题都被证明是凸的，并分析了复杂性。数值结果验证了理论性能分析，并展示了我们算法实现隐蔽通信的有效性和成功性。