A comparison of feedback schemes for network coding in wireless mesh networks

Intra-flow Network Coding (NC) has attracted extensive attention because that it can yield substantial performance gains in wireless mesh networks (WMNs). Feedback scheme is critical for almost all intra-flow NC protocols because the feedback can be used to inform the sender of the accomplishment of transmission as well as parameter adaptation, etc. The current feedback schemes in intra-flow NC technique mainly include two categories: Traditional feedback (TF) and Freedom feedback (FF). However, the performance comparison of these two types of feedback schemes has not been fully studied. In this paper, we model the two feedback schemes and compare their performance in WMNs. Through extensive simulations, we show that when the source uses small transmission intervals, FF outperforms TF in terms of both decoding delay and utilization, while FF has no advantage over TF under large transmission intervals. Furthermore, for both TF and FF, the performance degrades with the deterioration of link quality, and the trend is similar. We believe that this work can provide insight into the design of efficient intra-flow NC protocol in WMNs.