Abstract: In order to solve the problem of optimizing the security rate of full duplex relay eavesdropping channel with energy harvesting capability, a secure beamforming design was proposed under simultaneous wireless information and power transfer (SWIPT) method. An optimization problem was considered aiming to maximize the secrecy rate of the system by jointly optimizing the beamforming matrix, energy signal covariance matrix and the power splitting ration under the constraint of the energy harvesting of the relay and energy-harvesting node. Since this problem is a non-convex secrecy rate maximization (SRM) problem, We use a step-by-step optimization approach to turn the objective problem into two sub-problems was decoupled. The first subproblem can be recast as a two-level optimization problem. Among them, the outer optimization problem was solved by one-dimensional search, and the inner optimization problem was solved by semidefinite relaxation (SDR) technique. The second subproblem can be solved by one-dimensional search. Simulation results show that the proposed method increases the security rate of the system.

Key words: energy harvesting, simultaneous wireless information and power transfer, beamforming, physical layer security, full-duplex relay