An effective and scalable connectivity restoration heuristic for Mobile Sensor/Actor Networks

Due to inhospitable environments, the actors/sensors in Mobile Sensor/Actor Networks are subject to various damages which can disrupt the data delivery and cooperation. Typically, the damages affect the existing routes and may even cause network partitioning. In such a case, the set of actors/sensors disconnected from the rest of the network, namely a partition, can be re-connected with the network through topology adjustment by exploiting node mobility. However, movement of the nodes consumes significant energy which needs to be minimized. In this paper, we propose an effective yet scalable heuristic approach for restoring network connectivity while minimizing the total movement distance of the nodes. Given that the nodes can move to infinitely many locations in the damaged area, the basic motivation of the heuristic is to reduce the number of locations where the nodes can move. For this purpose, a minimum set of relay points is identified first by running a relay node placement heuristic that can ensure connectivity. Existing nodes in the partitions are then used to fill the relay points based on a greedy heuristic. When selecting nodes from the partitions, the nodes that do not cause further disconnectivity in the partition are picked. This is done by determining the connected dominating set of the partition and identifying the dominatee nodes. The experiment results show that the proposed approach not only performs very close to a near-optimal solution but also scales well when the number of nodes or partitions are increased.