Joint Design of Cooperative Beamforming and Jamming for Physical Layer Security Improvement in AF-based Two-Way Relay

Cooperative beamforming and jamming are two common techniques to enhance the Physical-layer security of a wireless transmission, in this paper, we study the problem that joint design of cooperative beamforming and jamming for secrecy rate improvement in AF(Amplify-and-Forward)-based two-way relay networks. Under the assumption that the full CSI is obtained, we propose a joint scheme that the relay not only adopt distributed beamforming but also jam the eavesdroppers. Then we compute the sum secrecy rate with the total power constraint. A two-step iterative algorithm is proposed to search the optimal cooperative scheme which can maximize the sum secrecy rate of the networks, and we compare it with a suboptimal cooperative scheme with low complexity. Simulations show that the proposed scheme searched by two-step approach is superior to suboptimal cooperative scheme in enhancing the security of the AF-based two-way relay networks.