Secure Beamforming for IRS-Assisted Nonlinear SWIPT Systems With Full-Duplex User
Yong Jin, Ruijie Guo, Lin Zhou, Zhentao Hu
Abstract
Physical layer security of wireless communication network with intelligent reflecting surface (IRS) is investigated in this letter. At the access point (AP) transmission power and user nonlinear energy harvest constraints, maximum secrecy rate of full-duplex (FD) user which employs simultaneous wireless information and power transfer (SWIPT) technology is achieved by jointly optimizing transmit beamformer of AP, IRS phase shift, and artificial noise power of FD user. Due to its undesirable properties, such as coupling of multiple optimization variables and non-convex objective function, original optimization problem is hard to be handled. We solved this problem by an alternating optimization algorithm consisting of semi-definite relaxation, Charnes-Cooper transform and continuous phase shifting discretization techniques to obtain a feasible suboptimal solution. Simulation results demonstrate that although may only guarantee to convergence a local optimal, proposed algorithm still achieves the best security rate comparing to the benchmark algorithms with the computational efficiency sacrificing.