Thanks to their quick placement and high flexibility, unmanned aerial vehicles (UAVs) can be very useful in the current and future wireless communication systems. With a growing number of smart devices and infrastructure-free communication networks, it is necessary to legitimately monitor these networks to prevent crimes. In this paper, a novel framework is proposed to exploit the flexibility of the UAV for legitimate monitoring via joint trajectory design and energy management. The system includes a suspicious transmission link with a terrestrial transmitter and a terrestrial receiver, and a UAV to monitor the suspicious link. The UAV can adjust its positions and send jamming signal to the suspicious receiver to ensure successful eavesdropping. Based on this model, we first develop an approach to minimize the overall jamming energy consumption of the UAV. Building on a judicious (re-)formulation, an alternating optimization approach is developed to compute a locally optimal solution in polynomial time. Furthermore, we model and include the propulsion power to minimize the overall energy consumption of the UAV. Leveraging the successive convex approximation method, an effective iterative approach is developed to find a feasible solution fulfilling the Karush-Kuhn-Tucker (KKT) conditions. Extensive numerical results are provided to verify the merits of the proposed schemes.

中文翻译：

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无人机支持的合法监控系统的能量管理和轨迹优化

由于其快速放置和高度灵活性，无人驾驶飞行器 (UAV) 在当前和未来的无线通信系统中非常有用。随着越来越多的智能设备和无基础设施的通信网络，有必要合法地监控这些网络以防止犯罪。在本文中，提出了一种新颖的框架，通过联合轨迹设计和能量管理，利用无人机的灵活性进行合法监控。该系统包括带有地面发射机和地面接收机的可疑传输链路，以及用于监控可疑链路的无人机。无人机可以调整位置并向可疑接收器发送干扰信号，以确保成功窃听。基于这个模型，我们首先开发了一种方法来最小化无人机的整体干扰能耗。在明智的（重新）公式的基础上，开发了一种交替优化方法来在多项式时间内计算局部最优解。此外，我们建模并包括推进功率，以最大限度地减少无人机的整体能耗。利用逐次凸逼近方法，开发了一种有效的迭代方法来找到满足 Karush-Kuhn-Tucker (KKT) 条件的可行解。提供了广泛的数值结果来验证所提出方案的优点。我们建模并包含推进功率以最小化无人机的整体能耗。利用逐次凸逼近方法，开发了一种有效的迭代方法来找到满足 Karush-Kuhn-Tucker (KKT) 条件的可行解。提供了广泛的数值结果来验证所提出方案的优点。我们建模并包含推进功率以最小化无人机的整体能耗。利用逐次凸逼近方法，开发了一种有效的迭代方法来找到满足 Karush-Kuhn-Tucker (KKT) 条件的可行解。提供了广泛的数值结果来验证所提出方案的优点。