Performance Analysis of Relay Selection with Enhanced Dynamic Decode-and-Forward and Network Coding in Two-Way Relay Channels

Relay selection (RS), enhanced dynamic decode-and-forward (EDDF), and network coding (NC) have been proven to effectively improve the performance of cooperative communications systems. This motivates us to combine these three techniques to see how they can improve the performance of cooperative communications systems. In this study, we adopt the RS protocol proposed by Bletsas, Khisti, Reed and Lippman in 2006. The protocol features an EDDF and NC system for two-hop two-way multirelay networks. All nodes are single-input single-output and half-duplex (i.e., they cannot transmit and receive data simultaneously). The outage probability and its asymptotic behavior at a high SNR, diversity gain, coding gain at a high SNR, multiplexing gain of the sum rate, and spectrum efficiency of the RS-DDF&NC and RS-EDDF&NC schemes were analyzed. In this paper, we present comparisons of the outage probability in various scenarios under the Rayleigh fading channel. Our results demonstrate that the RS protocol with the EDDF and NC scheme exhibits optimal performance regarding outage probability based on the considered DF relay scheme if there exist sufficient relays. In addition, the performance loss is large if a relay is selected randomly. This demonstrates the importance of RS strategies.