Artificial-Noise-Aided Secure MIMO Wireless Communications via Intelligent Reflecting Surface

Sheng Hong, Cunhua Pan, Hong Ren, Kezhi Wang, Arumugam Nallanathan

Research output: Contribution to journalArticlepeer-review

198 Citations (Scopus)
92 Downloads (Pure)


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.

Original languageEnglish
Article number9201173
Pages (from-to)7851-7866
Number of pages16
JournalIEEE Transactions on Communications
Issue number12
Early online date21 Sept 2020
Publication statusPublished - 1 Dec 2020


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