Research On Coverage Evaluation And Optimization Technology For Wireless Sensor Networks

As the forefront of the Internet of Things, wireless sensor networks(WSNs) has been widely used in all aspects of national life and production. Coverage as one of the most important issue in WSNs is that people are still hot research. The quality of coverage directly determines whether the result of a real and effective network monitoring, and monitoring tasks can proceed smoothly. Therefore, it is very necessary to study the evaluation and optimization methods of network coverage quality.This paper addressed above problem, in order to cover the evaluation and optimization of WSNs method as an object of study, summed up the results of previous experience and the issue on the basis of a detailed discussion and research.The main research content and innovation points are as follows:1. In wireless static sensor networks, a greedy coverage optimization algorithm is proposed, which bases on the geometric features of the networks. This algorithm avoided the high computational complexity by computing nodes ’ sensing range overlap, instead using computational geometric methods to evaluate and optimize the quality of coverage, greatly reduces the computational complexity. It activates only one sleeping node each round of turn to improve the coverage efficiency of single nodes as much as possible for achieving fewer nodes cover larger target area. Simulation results showed that the algorithm can rapidly improve coverage while reducing the number of nodes in use.2. For coverage evaluation problem, a novel coverage hole description method,called Hole-Tree, is proposed. It can portray position, shape and size of coverage hole more accurately compared to the conventional coverage hole description methods, and the detection results of Hole-tree get more closer to the real area and avoided a bug which would occur in conventional method. Simulation results confirmed the effectiveness and comparative advantages of the Hole-tree.3. In wireless hybrid sensor networks, a coverage hole patching algorithm named DHT is proposed, which utilizes mobile sensors to patch the detected coverage holes by Hole-tree method. Primarily, it divides the result of Hole-tree into several sub-Hole-tree according to specific principles. And then the certain key positions of sub-Hole-tree would be repaired. A parallel repair strategies is implemented in this algorithm, network will calculated multiple key positions to lead several mobile nodes to repairsimultaneously, per round. So it shortening the repairing time.4. The possibility of breakthrough is an criteria of coverage quality. In this paper,another coverage hole patching algorithm named BDH is proposed. It can enhance the quality of network coverage while reducing the possibility of the network be break. The core idea of the algorithm is the larger degree of branch point of Hole-tree, it has a higher priority to be repaired,thereby reducing the number of branches of coverage holes and improve the quality of network coverage.5. There were studied for the wireless directional sensor networks(DSNs)coverage problems. Conventional sector sensing model is simplified into a triangle one in this paper, and the scope of application of triangle model is determined, which is less than the angle of view 45. Based on this, a distributed coverage improvement greedy algorithm is proposed. This method is calculated on a per-node local Voronoi diagram,each node cover its own Voronoi cell as much as possible. Moreover, in order to avoid excess overlap between nodes, a sensing direction adjustment schedule has been considered to further increasing the coverage area of the network. Notably algorithm considers the mechanical energy of movement to bring huge loss factors, allow a certain extent at the expense of coverage to ensure that the angle of rotation of less additional energy cost savings. The simulation results show the effectiveness and superiority of the algorithm.