Artificial-Noise-Aided Secure MIMO Wireless Communications via Intelligent Reflecting Surface
Artificial-Noise-Aided Secure MIMO Wireless Communications via Intelligent Reflecting Surface
复制标题
通过智能反射表面的人工噪声辅助安全 MIMO 无线通信
DOI：
10.1109/tcomm.2020.3024621
复制
发表时间：
2020-12-01
影响因子：
8.3
通讯作者：
Nallanathan, Arumugam
中科院分区：
文献类型：
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作者：
Hong, Sheng;Pan, Cunhua;Nallanathan, Arumugam
研究了一种人工噪声辅助的安全MIMO无线通信系统。为了提高系统的安全性能，引入了先进的智能反射面（IRS），并在基站（BS）、合法信息接收机（IR）和窃听器（Eve）上配置了多根天线。以最大化保密率（SR）为目标，在发射功率限制和IRS相移单位模的约束下，联合优化BS的发射预编码（TPC）矩阵、AN的协方差矩阵和IRS的相移.然后，保密率最大化（SRM）问题，这是一个非凸的多耦合变量的问题。为了解决这个问题，我们建议利用块坐标下降（BCD）算法交替更新变量，同时保持SR非递减。具体地说，最佳TPC矩阵和AN协方差矩阵的拉格朗日乘子法推导，并通过优化最小化（MM）算法获得的最佳相移。由于所有的变量都可以在封闭的形式计算，所提出的算法是非常有效的。本文还将SRM问题扩展到更一般的多IR场景，并提出了一种BCD算法来解决该问题，仿真结果验证了通过IRS增强系统安全性的有效性。
This article considers an artificial noise (AN)-aided secure MIMO wireless communication system. To enhance the system security performance, the advanced intelligent reflecting surface (IRS) is invoked, and the base station (BS), legitimate information receiver (IR) and eavesdropper (Eve) are equipped with multiple antennas. With the aim for maximizing the secrecy rate (SR), the transmit precoding (TPC) matrix at the BS, covariance matrix of AN and phase shifts at the IRS are jointly optimized subject to constrains of transmit power limit and unit modulus of IRS phase shifts. Then, the secrecy rate maximization (SRM) problem is formulated, which is a non-convex problem with multiple coupled variables. To tackle it, we propose to utilize the block coordinate descent (BCD) algorithm to alternately update the variables while keeping SR non-decreasing. Specifically, the optimal TPC matrix and AN covariance matrix are derived by Lagrangian multiplier method, and the optimal phase shifts are obtained by Majorization-Minimization (MM) algorithm. Since all variables can be calculated in closed form, the proposed algorithm is very efficient. We also extend the SRM problem to the more general multiple-IRs scenario and propose a BCD algorithm to solve it. Simulation results validate the effectiveness of system security enhancement via an IRS.