Adaptive Relay Selection with Physical Layer Security for Green Communicaions

This paper investigates the issue of physical layer security for green communications. Specifically, the cooperative communication scenario which contains one source node, one eavesdropper, one destination and multiple cooperative nodes is considered. We aim at minimizing the total power consumption under the restriction of security performance. To achieve this goal, two novel cooperation strategies are proposed. The two methods are named as Only Relay and Relay and Jamming Pair. The former selects one relay node for cooperation. However, as the legitimate receiver's channel condition deteriorates, in order to satisfy security performance, the system would switch to the latter method, which selects a relay and jamming node pair for cooperation. The optimum node selection and power allocation method under the two strategies is studied. The performance of minimal power consumption under different circumstances is investigated. Numerical simulation results show that compared to traditional communication without cooperative node, the proposed methods result in less power consumption under security restriction.