Jammer selection for secure two-way DF relay communications with imperfect CSI

This paper investigates jammer selection in a two-way decode-and-forward (DF) relay network with imperfect channel state information (CSI). The proposed scheme enables an selection of one conventional relay and two jamming nodes to enhance communication security against eavesdropper. The conventional relay assists two sources to exchange their data via a DF protocol. The two jamming nodes are used to create interference signals to confuse the eavesdropper. Furthermore, the asymptotic performance of proposed scheme is analyzed in detail. Under the assumption that the relay can decode received signals perfectly and when the jamming power is higher than that of source nodes, we find that the proposed scheme has a high secrecy performance which is almost independent of the position of the eavesdropper.