Multi-Source Multihop Wireless Networks: A Trellis Representation and Network Coding

We consider practical network coding, a useful generalization of routing, in a dynamic wireless network comprising a set of nodes transmitting data wirelessly to a set of common destinations. It is shown that an arbitrary network can be transformed to a "trellis network", such that routing becomes equivalent to path discovery in the trellis. Exploiting a distributed, real-time matching-code-with-graph technique in each stage of the possibly time-varying trellis, a general network coding framework is developed. Depending on whether or not decoding is performed at the intermediate relays, three practical network coding categories, progress network coding, concatenated network coding and hybrid network coding, are investigated. Analysis shows that the proposed framework can be as dissemination- efficient as those with random codes, but only more practical.