Abstract
Considering the existence of a multi-antenna eavesdropper, the secure relay beamforming (SRO) problem for simultaneous wireless information and power transfer (SWIPT) in non-regenerative multi-antenna multi-relay networks is investigated. The objective is to maximize the achievable secrecy rate subject to individual transmit power constraint at relays and the energy harvesting (FIE constraint at FII receiver. Such an optimization problem is non-convex optimization problem and no tractable solution to the problem. In this paper, the optimization problem is transformed into several convex optimization subproblems. 'Therefore, the optimization problem can be handled by solving convex optimization sub-problems in an alternating fashion. The average achievable secrecy rate of our proposed AO-based SRB scheme is shown by simulation.