论文标题
通过智能反射表面增强安全的MIMO传输
Enhancing Secure MIMO Transmission via Intelligent Reflecting Surface
论文作者
论文摘要
在本文中，我们考虑了一种智能反射表面（IRS）辅助Guassian多输入多输出（MIMO）窃听通道（WTC），并专注于提高其保密率。由于MIMO设置，所有现有的解决方案都完全落入了这项工作。此外，所有现有的研究仅基于理想的假设，即可以使用Eavesdropper（EV）的完整信道状态信息（CSI）。因此，我们提出了数值解决方案，以提高完整和无EV的CSI案例下该通道的保密率。对于完整的CSI情况，我们提出了一种屏障方法和一对一优化的合并优化（AO）算法，以共同优化IRS发射器（TX）和相移系数的发射协方差R。对于NO EV的CSI，我们会开发人造噪声（AN）辅助的关节传输方案，以提高保密率。在此方案中，提出了一个二分线搜索（BS）和OBO优化合并的AO算法来共同优化R和Q。在特殊情况下，该方案也适用于提高秘密率，在这种特殊情况下，TX和接收器/EV之间的直接链接由于障碍而被阻塞。特别是，我们提出了A BS和较小的最大化（MM），将AO算法组合起来，并稍快地收敛，以优化R和Q对于此情况。仿真结果验证了所提出的算法的单调收敛性，并且表明，IRS辅助设计的拟议算法的保密率明显高于全CSI下的其他基准方案。当EV的CSI尚不清楚时，该渠道的保密性能也可以通过拟议的辅助方案来提高，并且在提高RX服务质量与提高保密率之间存在权衡。
In this paper, we consider an intelligent reflecting surface (IRS) assisted Guassian multiple-input multiple-output (MIMO) wiretap channel (WTC), and focus on enhancing its secrecy rate. Due to MIMO setting, all the existing solutions for enhancing the secrecy rate over multiple-input single-output WTC completely fall to this work. Furthermore, all the existing studies are simply based on an ideal assumption that full channel state information (CSI) of eavesdropper (Ev) is available. Therefore, we propose numerical solutions to enhance the secrecy rate of this channel under both full and no Ev's CSI cases. For the full CSI case, we propose a barrier method and one-by-one (OBO) optimization combined alternating optimization (AO) algorithm to jointly optimize the transmit covariance R at transmitter (Tx) and phase shift coefficient Q at IRS. For the case of no Ev's CSI, we develop an artificial noise (AN) aided joint transmission scheme to enhance the secrecy rate. In this scheme, a bisection search (BS) and OBO optimization combined AO algorithm is proposed to jointly optimize R and Q. Such scheme is also applied to enhance the secrecy rate under a special scenario in which the direct link between Tx and receiver/Ev is blocked due to obstacles. In particular, we propose a BS and minorization-maximization (MM) combined AO algorithm with slightly faster convergence to optimize R and Q for this scenario. Simulation results have validated the monotonic convergence of the proposed algorithms, and it is shown that the proposed algorithms for the IRS-assisted design achieve significantly larger secrecy rate than the other benchmark schemes under full CSI. When Ev's CSI is unknown, the secrecy performance of this channel also can be enhanced by the proposed AN aided scheme, and there is a trade-off between increasing the quality of service at Rx and enhancing the secrecy rate.
