An optimization framework of target secrecy rate and power allocation for SWIPT system

In the simultaneous wireless information and power transfer (SWIPT) system, due to the broadcast nature of wireless radio, the energy receiver may act as a potential eavesdropper to eavesdrop the information sent to the information receiver. To address this issue, in this paper, we propose an optimization framework of target secrecy rate and power allocation ratio based on secrecy outage probability and effective secrecy throughput in the SWIPT system over fading wiretap channel. Firstly, we formulate the effective secrecy throughput maximization problem under the reliability constraint in the on-off and adaptive transmission modes, and provide the optimal target secrecy rate. Furthermore, we formulate the secrecy outage probability minimization problem and the average harvested energy maximization problem, respectively. By solving the two optimization problems, we propose the corresponding optimal power allocation policy. Finally, we provide numerical results to evaluate the performance of the proposed policy in effective secrecy throughput.