Design of Secure Beamforming for the IRS-Assisted System of Simultaneous Wireless Information and Power Transfer Under Hardware Impairments

To improve the security of simulated wireless information and power transfer communication systems and overcome the impact of hardware impairments on the system transceiver, a secure beamforming design method for SWIPT systems assisted by intelligent reflecting surface (IRS) under hardware impairments was proposed. This method jointly optimized the beamforming vector of the base station, artificial noise vector, and IRS phase shift matrix, and constructed a secrecy rate optimization problem under multiple constraints such as maximum transmit power of the BS, the minimum receiving energy of the energy harvesting receiver, and IRS phase shift. Considering that the optimization problem is non convex and the variables are coupled, an effective algorithm based on alternating optimization and semi-definite relaxation is proposed to solve this problem suboptimally. Firstly, the original optimization problem is decomposed into two sub problems using alternating optimization. The first sub problem solves the beamforming vector and AN vector of the BS transmission, and the second sub problem solves the auxiliary vector of the IRS reflection coefficient. Finally, the SDR method is used to handle non convex constraints, and the alternating optimization method is employed to solve the subproblem. Simulation results show that the proposed method can guarantee the energy harvesting requirement, improve the security of system and mitigate the impact of hardware impairments.