PiggyCode: A MAC Layer Network Coding Scheme to Improve TCP Performance Over Wireless Networks

In this paper we propose PiggyCode, a network-coding based scheme specifically designed to enhance TCP performance over IEEE 802.11 multi-hop wireless networks. The root of this approach is a network coding module operating between the network and the MAC layer. Each node running PiggyCode encodes, whenever it is possible, TCP-DATA and TCP-ACK packets belonging to the same information flow. The coding approach is conceptually analogous to piggyback the TCP- ACK packet within the TCP-DATA packet, with the substantial difference that, by performing network coding operations, the actual packet size remains unchanged. The proposed scheme is simple and effective. It leverages the benefits of network coding in the wireless environment, to jointly reduce the overall number of transmissions on the channel and speed up the delivery process of TCP-ACK packets, thus achieving significant improvements in terms of TCP performance.