Study On Coverage Strategy In Wireless Sensor Networks

Coverage technology is one of the most important filed on the wireless sensor networks. It refers to gain the greatest degree of monitoring through the controlling of nodes' distribution and working condition. A good coverage control strategy can always use the lowest energy to obtain the most valid and sufficient information. Coverage has become one of the hottest topics in this field, for the hardware and energy is always limited in wireless sensor networks.This thesis presents a new idea for the deterministic area coverage problem. The main research work and results are as follows:1. In this thesis, the coverage of classical control strategy has been researched and the objectives and implementation process of various types of control problems are analyzed. We explained the classical model of coverage. Then we point two factors which constraining the implementation of this model.2. This thesis tries to describe the coverage problem from the viewpoint of digital image processing. By developing the mapping between area terrain information and gray scale, and the one between nodes sensing information and gray scale, This thesis uses the point operation, area operation and image segmentation to construct the model of sensor nodes and object area. Then, both of two parts are combined into one whole gray scale model. Through the calculating for the gray component, a fitness function for the heuristic was built.3. This thesis studied the genetic algorithm and particle swarm optimization. Then the coverage problem based on gray model was optimized by them. Through comparing both the exploring ability and mining ability of two optimizations, this thesis makes a choice to find the most suitable optimization to the whole coverage strategy.4. For the inadequacies of our new strategy, either the model or the optimization is improved. This thesis presents some new model like redundancy-evaluating model, multiple priorities model and the nodes model with noise, while some more complex problem of coverage can be described. In addition, this thesis presents a resurrection strategy for the dead nodes and reduces the losses.The results show that the new control strategy which using gray scale model can adapt more complex terrain of the coverage, and are able to gain a higher performance of computing speed. Through further improvements, this strategy may apply in practical large-scale complex networks coverage problem.