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

Abstract

This paper 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.

Weighted Sum Secrecy Rate Maximization Using Intelligent Reflecting Surface

“…, respectively, D r and D t are the number of antennas at the receiver (Rx) and the transmitter (Tx), respectively, while d r and d t are the antenna separation distance at the Rx and the Tx, respectively, λ is the wavelength, ϑ AoD and ϑ AoA are the angle of departure and arrival, respectively. In the following, similar to [33], we set β = 3, d r /λ = d t /λ = 0.5, ϑ AoA = tan −1 y IRS −y BS x IRS −x BS , and ϑ AoD = π − ϑ AoA , respectively.…”

“…Fortunately, the IRS technique can be exploited to overcome the challenge. Specifically, in [33] and [34], the authors investigated the IRS-aided secure MIMO transmission, where a MM based method and a two layer algorithm were proposed to maximize the secrecy rate, respectively.…”

6G Enabled Smart Infrastructure for Sustainable Society: Opportunities, Challenges, and Research Roadmap

“… Noise effect Only reflects the received signal. The use of artificial noise is helpful to the system [ 151 ]. The backscatter signals are weak and with a low signal-to-noise ratio.…”

Physical-Layer Security Improvement with Reconfigurable Intelligent Surfaces for 6G Wireless Communication Systems

“…These techniques have been proposed to improve the secrecy rate by maximizing the legitimate channel gain and minimizing the eavesdropping channel gain for private message transmission through the legitimate link. Furthermore, joint transmit beamforming and reflecting beamforming optimization with artificial noise (AN) or jamming signals have been proposed for PLS enhancement in various wireless networks [ 33 , 34 , 35 , 36 , 37 , 38 , 39 ]. These techniques aim to maximize the signal to interference-plus-noise ratio (SINR) for a legitimate user and to minimize SINR for the EVE by transmitting a signal that combines the private message and AN.…”