A distributed reorganization algorithm in wireless sensor networks

Wireless Sensor networks (WSN) are composed of a large number of sensor nodes which are normally battery powered. Since these nodes are often deployed in hazard environments, it is very difficult to change or recharge batteries. Some nodes' batteries may deplete faster than others because they undertake more transmission and reception tasks. Some of the depleted nodes may play a critical role in network connectivity, whose removal will separate the network into two or more pieces. Sub-networks disconnected to sink nodes can't send data to a base station any more. In this paper, we propose a distributed algorithm to prevent this crisis happening. In our algorithm, each node has the information of its neighbors and can predict whether it is a critical node. Once it identifies itself as a critical node, it triggers the network reconnection algorithm. SMAC is a contention-based MAC protocol explicitly designed for sensor networks and we integrate our algorithm onto S-MAC. Our algorithm is simulated and the simulation results show that it works well for connectivity maintenance in wireless sensor networks.