In this paper,a scheme of cooperative jamming with optimal relay selection and power allocation is proposed.The proposed scheme selects one node from the intermediate nodes as relay and the rest nodes as friendly jammers.The relay operates in amplify-and-forward (AF) strategy.Jammer weights are derived to null the jamming signals at the destination and relay node and maximize the jamming signal at the eavesdropper.Furthermore,a closed-form optimal solution of power allocation between the selected relay and cooperative jammers is derived.Numerical simulation results show that the proposed scheme can outperform the conventional schemes at the same power consumption.
[1] A D Wyner.The wire-tap channel[J].Bell Syst Tech J,1975,54(8):1355-1387.
[2] I Csiszar,et al.Broadcast channels with confidential messages[J].IEEE Transactions on Information Theory,1978,24(3):339-348.
[3] S K Leung-Yan-Cheong,et al.The Gaussian wiretap channel[J].IEEE Trans Inf Theory,1978,24(4):451-456.
[4] Y Liang,et al.Secure communication over fading channels[J].IEEE Transactions on Information Theory,2008,54(6):2470-2492.
[5] P K Gopala,et al.On the secrecy capacity of fading channels[J].IEEE Trans Inf Theory,2008,54(10):4687-4698.
[6] I Krikidis.Opportunistic relay selection for cooperative networks with secrecy constraints[J].IET Commun,2010,4(15):1787-1791.
[7] I Krikidis,et al.Relay selection for secure cooperative networks with jamming[J].IEEE Transactions on Wireless Communications,2009,8(10):5003-5011.
[8] B Rankov,et al.Achievable rate regions for the two way relay channel[A].Proceedings of IEEE International Symposium on Information Theory[C].Seattle:IEEE,2006.1668-1672.
[9] L Dong,et al.Improving wireless physical layer security via cooperating relays[J].IEEE Transactions on Signal Processing,2010,58(3):1875-1888.
[10] J Chen,et al.Joint relay and jammer selection for secure two-way relay networks[J].IEEE Transactions On Information Forensic and Security,2012,7(1):310-320.
2015, Vol. 43 
