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. S-MAC 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.