论文标题
主动智能反射地面辅助安全地面通信与无人机抖动
Active Intelligent Reflecting Surface Assisted Secure Air-to-Ground Communication with UAV Jittering
论文作者
论文摘要
由于移动性提供了额外的安全自由度，因此无人驾驶飞机（UAV）的通信是安全的空对地面（A2G）网络的有前途的解决方案。但是，由无人机本身的随机气流和身体振动引起的抖动特征对无人机通信的性能具有不可忽略的影响。考虑到无人机抖动的影响，本文提出了一种强大而安全的传输设计，该设计在新型的主动智能反射表面（IRS）的帮助下，其中IRS中的反射元素不仅调整了相移，而且还可以扩大信号的幅度。具体而言，在最严重的保密率约束下，我们的目标是通过在无人机 - 荷兰基地站（UBS）的Active IR反射系数和光束成形的强大关节设计来最大程度地降低传输功率。但是，由于其非凸度性，解决联合优化问题是一项挑战。为了解决这个问题，通过线性变化和线性矩阵不平等的线性近似对非凸面问题进行了重新制定。然后，我们将这个问题分解为两个子问题，即被动边界成形和Active IRS反射系数优化，并通过替代优化（AO）解决它们。最后，数值结果证明了在安全传输约束和无人机抖动的影响下，主动IRS在节省功率方面的潜力。
Unmanned Aerial Vehicles (UAV)-enabled communication is a promising solution for secure air-to-ground (A2G) networks due to the additional secure degrees of freedom afforded by mobility. However, the jittering characteristics caused by the random airflow and the body vibration of the UAV itself have a non-negligible impact on the performance of UAV communication. Considering the impact of UAV jittering, this paper propose a robust and secure transmission design assisted by an novel active intelligent reflecting surface (IRS),where the reflecting elements in IRS not only adjust the phase shift but also amplify the amplitude of signals. Specifically, under the worst-case secrecy rate constraints, we aim to minimize the transmission power by the robust joint design of active IRS's reflecting coefficient and beamforming at the UAV-borne base station (UBS). However,it is challenging to solve the joint optimization problem due to its non-convexity. To tackle this problem, the non-convex problem is reformulated with linear approximation for the channel variations and linear matrix inequality transformed by S-procedure and Schur's complement. Then, we decouple this problem into two sub-problems, namely, passive beamforming and active IRS's reflecting coefficient optimization, and solve them through alternate optimization (AO). Finally, the numerical results demonstrate the potential of active IRS on power saving under secure transmission constraints and the impact of UAV jittering.
