Performance study of hybrid decode-amplify-forward (HDAF) relaying scheme for physical layer security in wireless cooperative network

In this paper, the secrecy performance and power allocation of the signal-to-noise ratio-based hybrid decode-amplify-forward (HDAF) relaying protocol in wireless cooperative network are investigated to get security at physical layer. The performance metrics considered are secrecy rate and intercept probability. The Ergodic secrecy rate is approximated theoretically. The effect of relay and eavesdropper locations on the secrecy performance of the system is analyzed. It is found that maximum secrecy rate is obtained for the relay close-to-destination case and minimum for the relay close-to-eavesdropper case. Jamming schemes are superior in secrecy rate performance than without jamming schemes. To enhance the secrecy rate further with the optimized relay and jammer powers, invasive weed optimization (IWO) algorithm-based power allocation is proposed. Here, maximizing the secrecy rate is defined as the cost function for the proposed IWO algorithm-based power allocation. Comparative study is done over the conventional equal and proposed power allocation schemes for validation. The proposed power allocation scheme proved to be superior. Copyright (C) 2016 John Wiley & Sons, Ltd.