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Design And Simulated Implementation Of Coverage And Connectivity Mechanism In Three Dimensional Wireless Sensor Networks

Posted on:2012-08-26Degree:MasterType:Thesis
Country:ChinaCandidate:J R WuFull Text:PDF
GTID:2348330482455620Subject:Communication and Information System
Abstract/Summary:PDF Full Text Request
Two basic factors in wireless sensor networks (WSNs) are coverage and connectivity, by which the networks performance is influenced directly. Coverage reflects the performance of area or target detection in wireless sensor networks, while connectivity decides the reliability of communication between sensor nodes in the networks. With the extending and deepening of applications in wireless sensor networks, higher coverage degree and connectivity degree are requested by more and more applications in order to improving the performance of detection and reliability of communication. Under this background, a k-coverage mechanism and a topology control algorithm preserving k-connectivity are designded in this thesis.Current researches on coverage and connectivity in wireless sensor networks mainly focus on two dimensional (2D) planes, and adopt the assumption of sensors's random distribution. While in the real world, many pratical applications in wireless sensor networks are deployed in three dimensional (3D) spaces belong to three dimensional wireless sensor networks (3DWSNs), in which sensor nodes are determisticly deployed. So the related research consultions in two dimentsional wireless sensor networks can not be extended to three dimensional wireless sensor networks directly. Based on spactial tessellation theory, the performance of networks using cude, hexagonal prism and truncated octahedron in nodes deterministic deployment is analyzed contrastively. The truncated octahedron is selected to be filling polyhedra according to the comprehensive performance of networks. The size of truncated octahedron is calculated according to the sensing radius of node firstly while the k-coverage mechanism is designed. And then a subset of truncated octahedron vertex set is choosed as the positions of nodes deployed. Considering the uniform distribution of nodes and minimality of nodes, strategies of random and deterministic deployment for nodes are designed when at least k active nodes are selected in each truncated octahedron in nodes deployment algorithm. Given the case that coverage degree descends caused by coverage holes emerging, two coverage holes detection and recovery algorithms are designed based on the catalogues of recovery in filling polyhedra independently and cooperatively. At last, considering the shortage of cone-base topology control applied in three dimensional (CBTC-3D). a modified topology control algorithm is proposed while preserving k-connectivity in the networks unsing binary search to find neighbors in order to reduce the node degree and transmitted power with the goal of energy conservation.The k-coverage mechanism and modified topology control algorithm are implemented and performances are analyzed based on NS2 simulation platform. According to the simulation results, the k-coverage in three dimensional wireless sensor networks is realized effectively by the nodes deployment algorithms and coverage holes detection and recovery algorithms proposed in this thesis. Compared to the CBTC-3D, the modified topology control algorithm moves forward to reduce node degree and transmitted power extending the network survival time while preserving k-connectivity in three dimensional wireless sensor networks.
Keywords/Search Tags:Wireless sensor networks, Spactial tessellation theory, ?-coverage, ?-connectivity, Topography control
PDF Full Text Request
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