Hybrid cooperative relaying and jamming for secure two-way relay networks

In this paper, we address the physical-layer security of a two-way wireless transmission with the help of multiple inter-mediate nodes in the presence of an eavesdropper. We propose a hybrid cooperative relaying and jamming mechanism to enhance the security of the data exchange, where some intermediate nodes adopt distributed beamforming to improve the channel quality to legitimate terminals and others jam the eavesdropper, simultaneously. Two different schemes are proposed with and without the instantaneous channel state information (CSI) of the eavesdropper, respectively. The solutions of both schemes can be obtained by convex optimization techniques. Comparisons show that the proposed hybrid schemes greatly improve the security of the two-way relay networks.