关键词: 物理层安全, 保密能量效率, 无线携能

Abstract: This paper investigates simultaneous wireless information and power transfer in multiple-input-multiple-output system consisting of multiple multi-antenna eavesdroppers. In the case that the channel state information of the eavesdroppers can not be accurately obtained, the objective is to maximize the worst-case secrecy energy efficiency by jointly designing the beamforming matrix, artificial noise covariance matrix and power splitting ratio subject to transmit power constraint and energy harvest constraint. Based on fractional theory, the original non-convex problem is transformed into an equivalent optimization problem in subtractive form. By means of novel equivalent transformation, the problem of coupling between multiple optimization variables is solved and then the alternating optimization is avoided. With the aid of S-procedure and first order Taylor series expansion, the non-convex problem is transformed into a convex one. Based on Dinkelbach method, a two-level optimization iterative algorithm is proposed and simulation results are provided to show the effectiveness and convergence of the proposed algorithm.

Key words: physical-layer security, secrecy energy efficiency, simultaneous wireless information and power transfer (SWIPT)