Local Topology Assisted XOR Coding in Wireless Mesh Networks

Network coding has shown great potential to improve the overall throughput of wireless networks with broadcast nature. Existing network coding schemes (e.g., COPE) require information exchange among neighboring nodes, in order to correctly encode and decode the data packets. Such an approach results in significant overhead. Moreover, the information exchange can be delayed due to channel contention, and thus leads to inefficient coding (i.e., many missed coding opportunities). In this paper, we propose a new encoding strategy, XOR-Top, which relies on local topology information only, and uses bitwise XOR for packet coding. In addition, it proactively tries to decode coded packets stored in its buffer. Compared with COPE, XOR-Top can always accurately identify coding opportunities according to local topology, and consumes less bandwidth for signaling. Our simulation results have shown that Xor-Top improves the network throughput, by up to 240% over traditional unicast and up to 150% over COPE. Moreover, there is a significant reduction in average end-to-end packet latency.