Research On The Coverage Problem In Wireless Sensor Networks

Since 1990s, along with technique development of wireless communication, embedded computation, sensor and MEMS(Micro-Electro-Mechanical Systems) et al, people have paid more attention to micro sensor with the capability of sensing, computing and wireless network communication, and WSN(Wireless Sensor Networks) that is made up of such sensors.Network coverage and energy consumption are two primary problems in wireless sensor networks. The performance of a sensor network depends to a large extent on the sensor field coverage and its lifetime is determined by its energy consumption. While network coverage is closely related to network energy consumption, the deployment of sensor nodes is an important factor affecting the coverage of a sensor network. This thesis focuses on energy-efficient coverage control in wireless sensor networks and movement-assisted self-deployment of sensor nodes. It presents methods for energy-efficient node scheduling and self-organization, as well as techniques for coverage-centric sensor node deployment.In wireless sensor networks, the number of sensor nodes has direct relation to WSN' s cost and performance, such as robustness, fault-tolerance. And furthermore, it is considered at first as WSN is designed. Analyzing the coverage problem of WSN, the thesis proposes the concepts of efficient coverage area and efficient coverage area ration, the analysis formula is given that minimum number of sensor nodes is demanded in a given sensor field if the field is covered fully and seamlessly. Then, this article on wireless sensor network coverage at home and abroad to optimize the study of the problem of classification and comparison, the three kinds of the existing grid of the advantages and disadvantages of methods. Designed to take full advantage of each sensor node sensing coverage of the round, come to monitor the area, the sensor nodes, sensor coverage relationship.For certainty distributed network, the classification and research of coverage and connectivity in wireless sensor network are introduced briefly. Then, start with grid network, we proposed a new method of regular hexagonal grid plot for wireless sensor network. By means of theoretical proving and computing, the result shows that this method of grid plot not only demand less sensor nodes, but also have a very outstanding low energy-consuming characteristic.For random distributed network, we divided the monitored area into hexagonal grids with sensing radius. By means of mathematic inference, theoretical analysis and calculation, the relationship between number of nodes and complete coverage were got. Finally, The simulation results show that the model gives can achieve the partial coverage with any expectant percentage, achieve seamless network coverage in the deployment of the smaller node density, and maintain the network connectivity.