Power efficient organization of wireless sensor networks

recently as an effective way of monitoring remote or inhospitable physical environments. One of the major challenges in devising such networks lies in the constrained energy and computational resources available to sensor nodes. These constraints must be taken into account at all levels of system hierarchy. The deployment of sensor nodes is the first step in establishing a sensor network. Since sensor networks contain a large number of sensor nodes, the nodes must be deployed in clusters, where the location of each particular node cannot be fully guaranteed a priori. Therefore, the number of nodes that must be deployed in order to completely cover the whole monitored area is often higher than if a deterministic procedure were used. In networks with stochastically placed nodes, activating only the necessary number of sensor nodes at any particular moment can save energy. We introduce a heuristic that selects mutually exclusive sets of sensor nodes, where the members of each of those sets together completely cover the monitored area. The intervals of activity are the same for all sets, and only one of the sets is active at any time. The experimental results demonstrate that by using only a subset of sensor nodes at each moment, we achieve a significant energy savings while fully preserving coverage. I. INTRODUCTION Sensor networks are wireless networks comprised of a large number of miniscule devices equipped with one or more sensors, some processing circuits, and a wireless transceiver. Such devices are called sensor nodes. The dimensions of a sensor node are small enough to allow easy deployment of a large number of nodes into remote and inhospitable areas. Once deployed, sensor nodes organize a network, so that they can combine their partial observations of the environment. By combining those partial observations, a network offers to a user a global view of a monitored area. The source of energy for a node is most often an attached battery cell. Since the size of a cell is limited, the amount of available energy is also limited. Therefore, sensor network architectures and applications, as well as deployment strategies, must be developed with low energy consumption as one of the important requirements. We study the problem of the placement of sensor nodes into a monitored area and their organization so that the full coverage is achieved with minimal energy consumption. Specifically, we have developed a heuristic that organizes the available sensor nodes …