Reserch On Coverage Algorithm In Wireless Sensor Networks And Its Realization

Wireless Sensor Networks (WSN), which is an important development direction in the field of information science, combines with research results of many frontier fields, such as sensor technology, embedded computing technology, micro electro mechanical system (MEMS) and wireless communication. The coverage problem is not only a basic problem for researches on WSN but also an important index of measuring the quality of network service. Effective monitoring on targeted monitoring area can be achieved only when network satisfies the coverage in this area to some extent. On the one hand, the volume of sensor nodes is small and hardware resource it carries is limited; on the other hand, the power is supplied by battery so that its energy is limited. Therefore, researches on WSN coverage focus on how to improve the effectiveness of the network energy and maximize network life cycle.This thesis concentrates on discussing the major characteristics, advantages and disadvantages of classical WSN coverage algorithm. Based on the feedback from overlay network on targeted events, this thesis puts forward a classification method which divides coverage algorithm into target-driven algorithm and coverage-preserving algorithm. According to the classification method and determined algorithm performance index, this thesis classifies and comparatively analyzes several popular coverage algorithms. The results of analyses show that coverage-preserving algorithm is suitable for large-scale network application circumstance where events occur frequently, while target-driven algorithm is appropriate for network application circumstance where there is monitoring on accidental events.Directing at shortages of coverage algorithm of node residual energy in the aspect of balanced energy consumption and coverage preserving of network, this thesis puts forward an improved coverage algorithm based on residual energy of node. Compared to the original algorithm, the improved algorithm optimizes the selection of start nodes in each round of original algorithm. On the basis of comprehensive consideration of the coverage value of nodes and balanced energy consumption of network, a new mechanism for the selection of start nodes is proposed. This algorithm is featured by its independence of node location information. Besides, for this algorithm, nodes in the network run for working node by exchanging their own state information and residual energy value with their neighbor nodes so that the node whose residual energy value is large will enter working state and the other nodes will enter dormant state.According to simulated experiments, this thesis proves the effectiveness of improved algorithm in the aspects of network coverage preserving and balanced energy consumption etc.