Wireless Sensor Network Node Scheduling

Wireless sensor networks are integration of sensor techniques, nested computation techniques, distributed computation techniques and wireless communication techniques. Sensor networks are composed of a large number of sensor nodes that are densely deployed inside the phenomenon. Sensor nodes are limited in computational capacities and memory, so it is frequent to communicate with the remote base station and energy source provided for sensors is usually battery power without recharging. The network lifetime, which is measured by the time until all nodes have been drained out of their battery power or the network no longer provides an acceptable event detection ratio, directly affects network usefulness. Therefore, energy plays an important part. So we need design specific algorithms or protocols to reduce energy consumption as much as possible.Wireless sensor networks have a very high nodes density (even up to 20nodes/m~3), some problems may arise such as the intersection of sensing coverage. The data signals produced by neighbor nodes have a bigger relativity, namely sensor nodes may sense the same event and produce the same data, but base station don't need all the redundant data, and when they communicate with base station may cause interference, therefore energy will be wasted unnecessarily.Broadly used strategies for reducing energy consumption in wireless sensor networks is to dynamically manage the duty cycle, alternatively schedule some nodes into sleep mode and others keep active to provide service. To design such a mechanism, one must answer the following questions: 1.Which rule should each node follow to determine whether to enter sleep mode? 2. When should nodes make such a decision? 3. How long should a sensor remain in the sleep mode?This paper use the idea of coverage, after scheduling nodes should preserve full coverage of network, present detection of the redundant nodes based on Voronoi diagram and node-scheduling arithmetic. In the fist place, the detection arithmetic...