Secrecy Rate Optimization for Intelligent Reflecting Surface Assisted MIMO System
Secrecy Rate Optimization for Intelligent Reflecting Surface Assisted MIMO System
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DOI：
10.1109/tifs.2020.3038994
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发表时间：
2021-01-01
影响因子：
6.8
通讯作者：
Feresidis, Alexandros P.
中科院分区：
文献类型：
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作者：
Chu, Zheng;Hao, Wanming;Feresidis, Alexandros P.
研究了智能反射面(IRS)实现无线安全传输的影响。具体地说，IRS用于辅助多输入多输出(MIMO)安全系统提高保密性能，并使用人工噪声(AN)引入干扰来降低窃听者的接收。为了提高保密性能，我们通过联合设计保密传输的预编码、AN干扰和IRS的反射相移，在发射功率受限的情况下最大化可达到的保密率。我们首先提出了一种替代的优化算法(即块坐标下降(BCD)算法)来解决所提出的问题的非凸性。这是通过利用拉格朗日对偶方法得到发射预编码和AN矩阵，并通过优化最小化(MM)算法得到相移来实现的。我们的分析表明，所提出的BCD算法以单调非递减的方式收敛，从而得到保证的最优解。最后，我们给出了数值结果，与基准方案相比，验证了所提方案的保密性增强。
This paper investigates the impact of intelligent reflecting surface (IRS) enabled wireless secure transmission. Specifically, an IRS is deployed to assist multiple-input multiple-output (MIMO) secure system to enhance the secrecy performance, and artificial noise (AN) is employed to introduce interference to degrade the reception of the eavesdropper. To improve the secrecy performance, we aim to maximize the achievable secrecy rate, subject to the transmit power constraint, by jointly designing the precoding of the secure transmission, the AN jamming, and the reflecting phase shift of the IRS. We first propose an alternative optimization algorithm (i.e., block coordinate descent (BCD) algorithm) to tackle the non-convexity of the formulated problem. This is made by deriving the transmit precoding and AN matrices via the Lagrange dual method and the phase shifts by the Majorization-Minimization (MM) algorithm. Our analysis reveals that the proposed BCD algorithm converges in a monotonically non-decreasing manner which leads to guaranteed optimal solution. Finally, we provide numerical results to validate the secrecy performance enhancement of the proposed scheme in comparison to the benchmark schemes.