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Study On Energy-Hole Avoidance For Wireless Sensor Network

Posted on:2011-03-26Degree:DoctorType:Dissertation
Country:ChinaCandidate:Z W CengFull Text:PDF
GTID:1118360305992934Subject:Computer application technology
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Recently people focused their attentions on a hot international research frontier area the-Wireless sensor network (WSN), which is a multi-disciplinary and highly overlapping research area. It integrates highly with several subjects of knowledge and has the extremely broad application prospect and the practical value. Thus it is considered as one of the huge influential technique to the 21st century.As the wireless sensor node only provides limited power source and works in a bad environment, under the present condition, it is impossible to renew the energy greatly through the method of enhancing the battery capacity or shift the battery manually. Therefore, the energy is the rarest resources in the WSN. The most important issue in the WSN research is how to enhance the energy efficiently to lengthen the network lifetime. But the characteristics of the WSN data collection determine the formation of Energy hole (EH) phenomenon in the network because of imbalanced energy consumption, which causes the network failure. This dissertation aims at energy-hole avoidance in flat data-gathering WSN and deeply researched on the nodes in WSN with adjustable transmitting power, non-uniform node density WSN with buffer area and the EH avoidance strategy based on a mobile sink respectively. The research content and the achievement are as follows:1) Based on the correlation of data transmission speed, the energy consumption and the delay, it proposed a strategy of EH avoidance in the flat data-gathering WSN.The paper obtained the relationship between the quantity of the data and the transmitting radius r, then inferred the energy consumption in different network regions. It proposed a new method for balancing the energy consumption without increasing delay. The method is that the nodes with lower energy consumption adopt a higher data transmission rate, while the nodes with higher energy consumption maintain a lower data transmission rate. In this foundation, the system transmits part of the data primary toward the energy-hole region to the lower energy consumption region to balance the quantity of the data and the energy consumption, and it further lengthens the lifetime of the network. The data simulation demonstrated that the lifetime of the network has been lengthened by 17.48%, and the delay of the network reduced by 34.76%.2) In view of the flat data collection network, it has established the energy consumption model and proposed an EH avoidance strategy by deploying the node unevenly.Using the infinitesimal analysis method, the theoretical result of the network energy consumption in different regions is obtained. Therefore the uneven density curve of the node can be given. If the WSN's nodes were deployed on this density curve, the WSN energy consumption would be balanced theoretically. The simulation experiment indicated that this method can lower the remain energy to 20% below.(3) For the flat data-gathering WSN that its sink moves along the fixed buffer zone, optimized position of the buffer and the non-uniform node deployment density function are given, which can improve the network lifetime effectively.Using the infinitesimal analysis method, this paper established the energy consumption model for the WSN on which its sink moves along the fixed buffer zone. Based on the model, if the launch radius of the node and the position of the buffer zone were given, the energy consumption of the node on each point in the WSN can be calculated. We computed the energy consumption by each radius and each position. The optimization position of the buffer and the launch radius of the node lead the minimum energy consumption of the net, so we got them. Later we changed the minimum energy consumption to the node density function. Networks deployed on this density curve can balance node's energy consumption.(4) In view of the issue of the sink moving in the irregular convexity network, the heuristic algorithm has been proposed to determine the motion position of the sink,. This algorithm can avoid the energy hole and lengthen the lifetime of the network effectively.The paper analyzed the energy consumption of the node with the infinitesimal analytic method when the sink position is known. Then divided network into many small enough grids, calculated the energy consumption of each grids in the correspondence position of the sink. If the sink have collected data k rounds in some position, the next position of the sink can be selected as follows:1) obtain the total amount of the energy consumption that each grid has consumed, named it E1; 2) compute the amount of the energy consumption that each grid will consume when the sink is in one of the grids for collecting data k rounds, named it E2; 3) select the maximum from (E1+E2), named it E3.; 4) do 2) and 3) for the sink in every other grid. select the minimum form E3.named it E4. The sink position corresponding to E4 is the next position. The experimental result indicated that by this method the network life is 5 times longer than the ones with static sink about 6% longer than the ones whose sinks move on the borderline of the WSN.
Keywords/Search Tags:The wireless sensor network, the network lifetime, energy-hole avoidance, moving sink, variable transmitting power
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