Research On Energy-Efficiency Coverage Control Problems In Wireless Sensor Networks

Wireless sensor networks consist of low-cost, low-power tiny sensor nodes that can communicate with each other to perform sensing and data processing cooperatively. Energy consumption and network coverage are two primary problems in wireless sensor networks. The performance of a sensor network depends to a large extent on the sensor field coverage and its lifetime is determined by its energy consumption. Common routing protocols tend to only consider the energy efficiency of network connectivity, but ignore the quality of network coverage in the initial random placement of sensor nodes. Similarly, most of the coverage control algorithm can guarantee the good quality of network coverage, are dependent on the exact location of sensor nodes, but also increase the energy cost of the network. This thesis focuses on the energy efficiency and the quality of coverage.This thesis summarized the characteristics of wireless sensor network, structure, concept and network of energy efficiency, introduces the coverage problem and several different coverage control algorithms, and then analyzes the clustering routing algorithm. On this basis, two new algorithms based on different considerations are proposed.So far the clustering algorithm is considered an efficient way to perform energy management and to extend the network lifetime. Therefore, new protocols used the clustering idea to improve the energy efficiency of the network. And classical clustering protocol for wireless sensor networks LEACH (Low Energy Adaptive Clustering Hierarchy) is analyzed and discussed in detail, especially in the cluster-head selection and the cluster-heads communication. Based on the shortcomings of LEACH, new improved routing protocols are given:1) In order to solve the arbitrary of LEACH's cluster-head selection, an energy-efficient distributed clustering algorithm on coverage (ECAC) is proposed. It considering the coverage of networks and the remaining energy of node, means that the nodes with high coverage redundancy as much as possible to act as cluster-head, while the time with the operation of the network increased the probability of the node with more remaining energy as cluster head. So it can ensure higher coverage, balance the energy consumption, and extend the effective life time of network.2) For the problem of LEACH protocol routing cluster head of the single-hop communication, a cluster-heads multi-hop routing protocol on coverage (ECAC-M) is proposed. It follows ECAC algorithm cluster head selection mechanism, cluster-head and base station communications using multi-hop communications. Each cluster-head is based on its distance from the base station and energy to construct multi-hop path tree. And one cluster-head send data to the base station through the multi-hop path tree's root node. Finally, the distance constraint which can ensure cluster-heads multi-hop to save energy is proved.The simulated experiments of LEACH, ECAC and ECAC-M are developed on NS-2 platform. The results show that all of the improved algorithms are better than LEACH in the performance of the network coverage and saving energy.