Relay Selection for Physical Layer Security in Decode-and-forward Two-way Relay Networks

Abstract

Relay selection for physical layer security is investigated in Decode-and-forward (DF) two-way relay networks, consisting of a group of intermediate nodes, two sources, and one eavesdropper. Three intermediate nodes are selected in the two transmission phases. One intermediate node is selected to perform the relaying operation, and the other two are selected to transmit the jamming to deteriorate the eavesdropping channels. It is found that the cooperative jamming scheme outperforms the conventional non-jamming scheme in the common scenario, where the intermediate nodes are distributed dispersedly. However, when the intermediate nodes cluster gets close to the sources, it is not superior any more due to the strong interference on the destinations. Therefore, an instantaneous switching between the nonjamming scheme and the jamming scheme is proposed to avoid the negative interference. The hybrid scheme is validated to well improve the secrecy performance of DF two-way relay networks via simulation analyses.