Improving Secrecy Outage and Throughput Performance in Two-Way Energy-Constraint Relaying Networks Under Physical Layer Security

In this paper, we propose three secrecy cooperative transmission protocols for a two-way energy-constrained relaying network in which two sources wish to exchange information with the help of multiple intermediate relays being subjected to wiretapping by multiple eavesdroppers. In the secure two-way communication (STW protocol), an energy-constrained relay is preselected via one of three investigated relay-selection strategies, which harvest the energy from the radio-frequency signals of one source and decode-and-forward the signals to another source. In secure two-way communication with network coding (STWNC protocol), the network coding technique is applied at a relay preselected via one of two investigated relay-selection strategies. In secure two-way communication with cooperative jamming and network coding (STWJNC protocol), under cooperative jamming, the network coding technique is applied at two sources and a preselected relay where a jammer-relay pair is preselected via one of two investigated selection strategies. The power-splitting receiver is applied at the energy-constrained relay for all proposed protocols. To evaluate performance, we derive new closed-form expressions for the secrecy outage probability and the throughput performance of the three protocols with the different relay and jammer-selection strategies. Our analysis is verified using Monte Carlo simulations.