NCFF: Efficient network coding with freedom-based feedback in Wireless Mesh Networks

Network coding can greatly increase the network transmission efficiency in Wireless Mesh Networks (WMNs), by combining multiple input packets into one packet algebraically before forwarding. Feedback scheme is critical for almost all network protocols, as it is helpful for transmission accomplishment notification as well as parameter adaptation, etc. Most used feedback schemes for network coding protocols allow the destination node to acknowledge the completion of batch only when it can be decoded. Hence, the feedback packet may experience a long latency to arrive at the source node, due to the lossy and multi-hop characteristics of WMNs. This will lead to great degradation of performance in terms of throughput, etc. In this paper, we propose NCFF, an efficient network coding protocol with end-to-end freedom-based feedback in WMNs. The freedom-based feedback employed in NCFF can reflect the reception of the receiver gradually and accurately. Compared with MORE, extensive simulations show that NCFF improves the performance in terms of throughput, normalized packet overhead and end-to-end delay, by up to 2×, 1.76× and 2.7× respectively.