Optimal Data Rate and Opportunistic Scheme on Network Coding over Rayleigh Fading Channels

Because wireless network coding technology may increase the total throughput in wireless networks, it has attracted a lot of attentions. However, there is few work focusing on wireless network coding over fading channels. In fact, signal fading usually occurs in wireless communications, resulting in the performance degradation of wireless networks seriously in some scenarios. To improve the throughput of wireless networks, we analyze network coding over Rayleigh fading channels, and formulate the fading compensation as an optimization problem. By solving the optimization problem, the optimal data rate is obtained. Numerical results and simulation results indicate that if the relay node transmits packets at the optimal data rate, the total throughput will increase. We also consider the selection of relay nodes, and give the optimal assignment location of relay nodes, which will increase the total throughput. In addition, based on the concept of optimal data rate proposed in this paper, an opportunistic optimal network coding (OONC) scheme is presented, which performs well under various situations.