Secrecy Rate Maximization under Improved Relay Selection with Different Coding Schemes for Cooperative Wireless Network

Abstract: Wireless communications system strategies are required that be dependent on the impending of the physical (PHY) layer to consent a transmitter-receiver pair communicate securely in the attendance of one or additional eavesdroppers. Communication is accomplished with the help of numerous trusted relays, via the amplify-and-forward (AF) or decode-and-forward (DF) protocol, and presumptuous knowledge of global channel state information (CSI). As an alternative, of dealing with information-theoretic security, we assume that eavesdroppers have bounded resources, and therefore we need to assure that the transmitted information is computationally secure; this is shown to impose constraints on the maximum power of the signals received by the eavesdroppers. Cooperative structures are a means to increase the performance of secure wireless communications. In this paper, we propose an improved relay selection scheme, based on source-eavesdropper channel SNR restriction, The first scheme tries to reduce the overheard information at the eavesdroppers by choosing the relay having the lowest instantaneous SNR to them both between source to relay (ER) and relay to desitnation (RE). The second is a conventional selection relaying one which seeks the relay having the highest SNR to the destination. Various DF (Convlution Codes, RS codes, Turbo Codes) relaying is used in order to find the best relaying technique. Performance has been studied in terms of secrecy rate, outage probability and average error probability (Symbol and bit error rates). Simulations shows that the proposed scheme outperforms in terms of the secrecy rate and error rate at the destination when compared to techniques in the literature.

Keywords: Cooperative Communication; Cooperative Secrecy; Cooperative diversity; Multiple Eavesdropper; Amplify & Forward; Decode & Forward; Maximum ratio combining algorithm; Best Relay Selection Scheme.