Secure communication of IRS based on weighted fractional Fourier transform

Using 4 weighted-typed fractional fourier transform (4-WFRFT) and artificial noise (AN)，a multiple-input multiple-output (MIMO) wireless communication system assisted by intelligent reflective surface (IRS) based on artificial noise and weighted fractional Fourier transform was proposed．In order to improve the channel quality，intelligent reflective surfaces were introduced into the communication system composed of base stations (BS)， legitimate users (LU) and eavesdroppers (Eve)， and further，artificial noise was introduced and weighted Fourier transforms were used to improve the security performance of the system．With the maximum secrecy rate (SR) as the goal，and the transmission power limitation and intelligent reflective surface phase shift unit mode as constraints， the transmit precoding (TPC) matrix of the base station， the covariance matrix of AN and the intelligent reflective surface phase shift were jointly optimized．Since the proposed problem is a non-convex problem，the block coordinate descent (BCD) algorithm was used to alternately update variables while keeping the SR not decreasing，and finally the effectiveness of the method was verified to improve the system security through simulation results. © 2023 Huazhong University of Science and Technology. All rights reserved.