Network Coding-Based Protection of Many-to-One Flow Networks

Survivability of many-to-one flow networks such as wireless mesh networks (WMNs) and wireless sensor networks (WSNs) is an important issue that has not received enough attention in the literature. Traditional proactive and reactive protection schemes are either resource-hungry like the (1 + 1) protection scheme, or introduce a delay and interrupt the network operation like the (1 : N) protection scheme. In this paper, we present a novel approach that relies on network coding to provide protection to many-to-one flows as in WMNs or WSNs at the speed of proactive protection, but at the cost of reactive protection. We derive and prove the necessary and sufficient conditions for our solution on a restricted network topology. Then we introduce three generalizations of our problem, and provide a heuristic and a mixed integer linear program (MILP) to solve one of them. We also show how to perform deterministic coding with {0,1} coefficients to achieve linear independence. Finally, we discuss some practical considerations related to our approach, and define a more general problem that takes these considerations into account. We also formulate this general problem as an MILP.