Rearch On K-coverage Mechanism For 3-D Wireless Sensor Networks

Wireless sensor network is a self-organizing network system, which is mainly consist of a large number of sensor nodes with wireless communications and computing power. This thesis focuses on the coverage of the sensor network. Currently, the research of wireless sensor network is mostly on two-dimensional sensor networks, but the reality is often the need to deploy sensor nodes in three-dimensional space.For the K-coverage of the omnidirectional wireless sensor network in three-dimensional space, Thesis will be from two aspects of deterministic and random coverage to deploy the sensor nodes to realize K-coverage in the three-dimensional monitoring area. In deterministic coverage, the entire monitoring area is divided into several polyhedrons which the external diameter of the ball is the sensors radius Rs, and deploy sensor nodes at vertices of each polyhedron, so that the lowest rate of coverage redundancy in monitoring area. In the random deployment, in three-dimensional monitoring area deploy nodes randomly, the initial state of the sensor nodes are working, and transfer the respective node position information to the sink. At first, choose K sensors in polyhedron overlapping area to keep it working, remaining dormant; if not reached K-coverage, in the polyhedron choose sensors to achieve K-coverage, and the rest to sleep.For the K-coverage of the directional wireless sensor network in three-dimensional space, a major study to scheduling policy which is effectively improved the efficiency of network coverage, the policy making and using wireless sensor networks satisfy K-coverage. Firstly, introduce a three-dimensional model of directional sensor network and the coverage range of each sensor node; secondly, the introduction of a meshing method used to calculate the coverage of wireless sensor networks, and can determine the node redundancy or coverage holes; and finally proposed a hierarchical scheduling policy by the sensor node moves in the vertical direction to increase the coverage area of the sensor nodes, in order to improve network coverage target monitoring area.Finally, we study the problem of a three-dimensional re-coverage, which is to study the virtual force between the sensor nodes such that each sensor nodes uniformly distributed in the target monitoring area, thereby increasing the efficiency of the network coverage.