This paper considers unmanned aerial vehicle (UAV)-carried intelligent reflecting surface (IRS) for secure data collection in wireless sensor networks. An eavesdropper (Eve) lurks within the vicinity of the main receiver (Bob) while several randomly placed sensor nodes beamform collaboratively to the UAV-carried IRS that reflects the signal to the main receiver (Bob). The design objective is to maximise the achievable secrecy rate in the noisy communication channel by jointly optimizing the collaborative beamforming weights of the sensor nodes, the trajectory of the UAV and the reflection coefficients of the IRS elements. By designing the IRS reflection coefficients with and without the knowledge of the eavesdropper's channel, we develop a non-iterative sub-optimal solution for the secrecy rate maximization problem. It has been shown analytically that the UAV flight time and the randomness in the distribution of the sensor nodes, obtained by varying the sensor distribution area, can greatly affect secrecy performance. In addition, the maximum allowable number of IRS elements as well as a bound on the attainable average secrecy rate of the IRS aided noisy communication channel have also been derived. Extensive simulation results demonstrate the superior performance of the proposed algorithms compared to the existing schemes.

中文翻译：

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无人机携带智能反射面的无线传感器网络中安全数据收集的联合波束成形和位置优化

本文考虑了无人机（UAV）携带的智能反射面（IRS）在无线传感器网络中的安全数据收集。窃听者（Eve）潜伏在主接收器（Bob）附近，而几个随机放置的传感器节点协同协作地波束形成到无人机携带的IRS，该信号将信号反射到主接收器（Bob）。设计目标是通过共同优化传感器节点的协作波束成形权重，UAV的轨迹和IRS元素的反射系数，来最大化噪声通信信道中可实现的保密率。通过设计带有或不带有窃听者通道知识的IRS反射系数，我们针对保密率最大化问题开发了一个非迭代的次优解决方案。分析表明，通过改变传感器分布区域而获得的无人机飞行时间和传感器节点分布的随机性会极大地影响保密性能。此外，还得出了IRS元素的最大允许数量以及IRS辅助噪声通信信道可达到的平均保密率的界限。大量的仿真结果证明了与现有方案相比，所提出算法的优越性能。还得出了IRS元素的最大允许数量，以及IRS辅助噪声通信信道可达到的平均保密率的界限。大量的仿真结果证明了与现有方案相比，所提出算法的优越性能。还得出了IRS元素的最大允许数量，以及IRS辅助噪声通信信道可达到的平均保密率的界限。大量的仿真结果证明了与现有方案相比，所提出算法的优越性能。