Research On Deployment Model Based On Coverage In WSNs

In the deployment of Wireless Sensor Networks(WSNs),there may be overlapping of sensing areas of nodes or a large quantity of redundant nodes in some area of the network.In one hand,such problems lead to wasting of energy of nodes and make communication channels busy.On the other hand,there may appear blind areas which could not be sensed by the sensor nodes,resulting in the decreasing of reliability and credibility of the network.At the same time,not only should the coverage problem be considered,but also the connectivity between nodes.As there might be unanticipated loss after deployment,the problem will not be solved with only 1-connectivity.The deployment models and topology control methods of Wireless Sensor Networks' coverage problem were researched in depth in this paper.It mainly embodied in following four aspects:(1) Paying a great effort on the algorithms of coverage controlling strategy,and mainly focusing on the analysis of the region coverage and barrier coverage which paved the way for the following optimizing designing of topology of the network.(2) An optimized solution was proposed based on Voronoi polygons after we have analyzed at least 2-connectivity and considered factors of optimization of WSNs' coverage control,effects of sensor models,restrictions and nodes efficiency.Thus,the full coverage and 2-connectivy are implemented.The sensing range can be described as a set of Voronoi polygons which includes every node with 1-to-1 mappings between Voronoi polygons and sensor nodes.So the minimum numbers of nodes used in the network can be evaluated through maximum value of corresponding Voronoi polygons,then the cost of network is greatly reduced.(3) For the redundant problem of nodes in sensing boundary of sensing region,an optimization deployment strategy was proposed based on the topological controlling of boundaries.Coverage deployment was divided into vertical deployment and horizontal deployment on the premise of maintaining global property of network topology.The paper combined with internal relations between network connectivity and connection angles according to theories of geometrical topology efficiently.Deployment of the 3 kinds of basis patterns was optimized and the differentia of optimal solutions and reliability of models were proved. (4) The paper verified the performance of all the solutions proposed in this paper by simulation considering the factors of different deployments,connectivity of network, positions of nodes and the utilizations rate of nodes.The simulations show that,the optimization pattern based on Voronoi polygon of this paper is better than deployment pattern in corresponding works,which achieved better coverage results with fewer nodes.Also,topological graph of nodes deployment network is plotted for optimization deployment models based on boundary topology.The experiment illustrates that every deployment model has a predominant advantage in a certain situation. However,when the ratio of communication radius and sensor radius is between[1.73,2),the triangle pattern based on 6-connectivity shows great superiority,and compared to the models based on 4-connectivity and 3-connectivity,the average number of nodes used reduced by 23.9%and 50.0%separately,while the efficiency of nodes reaches as high as 82.7%.