Minimum cost flow solution for tolerating multiple node failures in wireless sensor networks

In a wireless sensor network (WSN), nodes probe their surroundings and collaboratively perform situational assessment. Given the need for information sharing, maintaining inter-node connectivity is a primary requirement. However, the failure of a node due to energy depletion or physical damage may cause the network to get partitioned into disjoint segments and thus hinders data delivery and inter-node coordination and thus degrades overall network operation. This paper presents a Recovery algorithm that forms a topology with Increased Robustness against recurrent failure (RIR). RIR tolerates the failure of multiple connectivity-critical nodes through repositioning of healthy nodes. The approach favors substituting a failed node with one with the highest residual energy in order to sustain the network connectivity for the longest time. RIR models the recovery as a Minimum Cost Flow problem to determine the best set of node relocations for repairing the network topology while minimizing the motion overhead of the recovery process. The effectiveness of RIR is validated through simulation.