A New Mechanism to Incorporate Network Coding Into TCP in Multi-radio Multi-channel Wireless Mesh Networks

Most of the approaches in the application of network coding either require the overhearing opportunity or have bad interaction with TCP. A new mechanism, named TCP-I²NC, is proposed in this paper to incorporate network coding into TCP in interference-free multi-radio multi-channel wireless mesh networks where there are nearly no overhearing opportunities. Multiple TCP flows are coded together and forwarded in block by hop-by-hop ACK and retransmissions in TCP-I²NC. Several encoding blocks are working simultaneously to effectively utilize available bandwidth. However the maximum of encoding blocks is adaptively adjusted according to the bandwidth, propagation delay and packet loss rate of a wireless link, and also back pressure algorithm is used to perform flow and scheduling control. The end-to-end delay is optimized so that TCP-I²NC is applicable to delay-sensitive applications. Simulations show that our mechanism both significantly improves the throughput of TCP and derives a relatively short end-to-end delay as losses increase. And the delay jitter of TCP-I²NC is also very small. TCP-I²NC also achieves complete fairness in resource allocation.