A recursive coding algorithm for two-unicast-Z networks

We derive a new linear network coding algorithm for two-unicast-Z networks over directed acyclic graphs, that is, for two-unicast networks where one destination has apriori information of the interfering source message. Our algorithm discovers linear network codes for two-unicast-Z networks by combining ideas of random linear network coding and interference neutralization. We show that our algorithm outputs an optimal network code for networks where there is only one edge emanating from each of the two sources. The complexity of our algorithm is polynomial in the number of edges of the graph.