Distributed approach for reconnecting disjoint segments

Due to low-risk and cost-effectiveness, Wireless Sensor Networks (WSNs) have become the primary choice for serving in inhospitable environments like battlefields or security surveillance. In these application setups, nodes operate in harsh conditions and become susceptible to failure. In addition, the environment makes it dangerous and sometime impossible to replace a node that depletes its energy or gets damaged. When multiple nodes fail at the same time the network may get partitioned into disjoint segments and its service may significantly degrade or even cease. Therefore, the network must self-heal using existing resources. The major loss of connectivity and the lack of centralized control leave distributed recovery procedures as the most appropriate option for recovery. In this paper we present DarDs, a distributed approach for reconnecting disjoint segments. The basic idea is to determine the position of the fewest relay nodes that enable the network to restore connectivity. Then, nodes are moved from the individual segments to the designated relay positions such that the total travel overhead is minimized. The performance of DarDs is validated through mathematical analysis and simulation.