Performance Analysis of Hybrid Decode-Amplify-Forward (HDAF) Relaying for Improving Security in Cooperative Wireless Network

Abstract

In present communication scenario, security and privacy of data being transmitted is very difficult due to the openness of wireless medium. To secure and protect the confidentiality of data being transmitted, physical layer security offers attractive solutions using cooperative relaying schemes, in which relay assists the transmission of data between source and destination. In this work, we consider a cooperative wireless network in which relay either tries to improve the channel capacity of source to destination link using cooperative relaying protocols or reduce the channel capacity of source to eavesdropper link using jamming techniques. In order to improve the performance of the communication system, optimal relay and jammer are selected based on the three proposed relay and jamming selection schemes namely Conventional selection (Without jamming), Optimal selection with jamming (OSJ) and Optimal selection with control jamming (OSCJ).Optimal relay forwards the source information using cooperating relaying protocols such as decode and forward(DF), Amplify and Forward(AF) ,Hybrid decode amplify forward (HDAF) which combines the benefits of both DF and AF schemes. At the same time, jammer generates artificial noise using cooperative jamming scheme, to confuse the eavesdropper. The received signals at the receiver are combined using the various diversity techniques such as maximum ratio combining (MRC) and fixed ratio combining (FRC) techniques.Monte Carlo simulations are carried out and the obtained results are compared for different relay,jammer and eavesdropper locations. A study of comparison is made in terms of secrecy capacity and intercept probability for the proposed relaying schemes in the presence of single eavesdropper. Finally from the simulated comparison study, it is observed that HDAF scheme outperforms AF and DF schemes and we can also observe control jamming selection achieves more secrecy rate compared to without jamming and with optimal jamming.