A Node Scheduling Algorithm Based On Energy-probe In Wireless Sensor Network

Wireless sensor network consists of a large number of Energy-constrained,short-live, Unreliable sensors. sensor node'spower supply is usually provided by portable power , because the battery has limited energy, it is difficult to change the battery or charge it as the node's working environment restricted, that influenced the network lifetime, So conserving energy and prolonging network lifetime is one of the main design goal.A large number of sensors deployed in high density .There are a certain number of redundant nodes in Wireless sensor network. Making these nodes sleep does not affect the allover system function. An energy-effiect strategy to reduce network energy consumption and extend lifetime of network is schedule these nodes to work altematively. This algorithm is Base of energy conservation research in this paper.According to research of domestic and abroad, the algorithm has two kinds: deterministic and stochastic scheduling. Deterministic scheduling algorithm will accurately identify redundant nodes, and set these nodes to sleep model. It needs location information of each sensor node. It is very difficult to do in practical applications; at stochastic scheduling algorithm, the node has P sleep-probability or 1-P probability to work. The algorithm does not require complete coverage of the network, just to maintain a certain cover rate. Through many experiments under TinyOS found that the length of each node's work time is vary greatly in the implementation process of stochastic scheduling algorithm. The area in which sleep node are rarely covered, called uncover-region.Uncover-region harms greatly the system function. There is meaninglessthe,if scheduling algorithm can not guarantee the system function.For Uncover-region of stochastic scheduling algorithm, a Node scheduling Algorithm Based on Energy-probe (NABE) was proposed in this paper,The algorithm uses the variance to reflect the current state of regional energy, and set the network energy state Thresholdσt as acceptable state of network energy. Every X rounds NABE algorithm using energy-probe mechanism to detect state of network energy, based on current state network energy to carry out energy amendment,keep the balanced-energy among nodes,reduce the phenomenon of uncover-region.Analytical and simulation in OMNeT,the results show the mechanism can extends the network lifetime while have a high Coverage Rate and keep Balanced-energy.