Research On The Discovery And Restoration Of Bilnd Spots In Wireless Sensor Network

Wireless sensor network technology is a technology developed rapidly this year, it covers microelectronics, radio communication and computer technology and other disciplines. It is deployed in a network of a large number of tiny sensor nodes to monitor the area through self-organization and the formation of a wireless communication. With the development of science and technology, longer life, lower cost and more powerful sensor nodes been developed, wireless sensor network apply to more and more areas, such as modern logistics, smart home, urban transport, etc. Wireless sensor networks provide more convenient and intelligence lifestyle to human, and play an active role in scientific research, for example space exploration. All countries in the world attach great importance to research on wireless sensor networks, our country also included in the "National Long-term Science and Technology Development Plan" in wireless sensor network technology as the key research field of the country future development.The coverage problem in wireless sensor networks is a key research topic, it directly reflect the integrity of the perceived ability of network and data collection, become an important evaluation indicators to evaluate the quality of network service. In reality the position sensor node deployment is not reasonable, or part of a network node failure as destruction or energy depletion in the course of their work, these are likely to produce the coverage holes caused by covering problem. Detection data will be incomplete by network collected when coverage hole generating, incomplete data will not provide strong support for the command and control center of the decision-making. Therefore, we should try to avoid the coverage holes. When the network have covered holes should be immediately after opening holes detection algorithm to find the hole and repair them. The main work of this paper is to detect and repair the coverage holes, specifically include the following two aspects:Hole Detection. This paper introduces the current widespread use of detection algorithm based on computational geometry of the cavity, to find the defects existing in the algorithm, in-depth analysis the causes of defects. And improved the original algorithm, make a cavity detection algorithm based on polar coordinates. In order to verify the feasibility of improved algorithm, for improved algorithm simulation experiments in the simulation software MATLAB, and compare the former algorithm from detecting accuracy. Experiments show that, the improved algorithm and the original algorithm is same in the complexity but accuracy is greatly improved.Hole Repair. In order to guarantee the validity of the wireless sensor network, we need repair the coverage hole existed in the network. This paper present a hole repairing algorithm based on mobile node——"The joint patch method". The traditional repair algorithm based on the mobile node for compute-intensive and higher dependency on empty boundary location, this algorithm has the advantages of less computation, less dependent on boundary nodes and higher utilization of mobile node, especially, proposed the four kinds of patch sewing, these four schemes has each own good points, can be flexibility to choose each one according to the actual situation. Finally, the simulation platform of MATLAB to analyze the number of mobile nodes required the algorithm redundancy, experiments show that compared with the traditional algorithm——Algorithm of PATT, the lower algorithm of redundant but the higher utilization rate of node is a better algorithm.