Secure wireless communications with relay selection and wireless powered transfer

In this paper, we investigate the secrecy performance of an energy harvesting relay network, where a legitimate source communicates with a legitimate destination via the assistance of multiple trusted relays. In the considered system, the source and relays deploy the time-switching based radio frequency energy harvesting technique to harvest energy from a multi-antenna beacon. Different antenna selection and relay selection schemes are applied to enhance the security of the system. Specifically, two relay selection schemes based on the partial and full knowledge of channel state information are proposed. The exact closed-form expressions of the systems secrecy outage probability in these schemes are derived. A Monte-Carlo based simulation validates our analysis results.