The Path-planning Strategy For Mobile Sink And Network-repairing Strategy In Wireless Sensor Networks

The sensor node in wireless sensor networks has limited energy, and it is difficult to be recharged for the sensor node. So energy factor is one of the key issues which should be considered in design of wireless sensor networks. Hot spots of the network always appear due to node’s transporting data by multi-hop, which is unfavorable for energy balance of the network. Employing a mobile sink node can balance the energy consumption among sensor nodes, so the research on the moving strategy of sink nodes attracts more and more attention in recent years. In harsh environments, such as the result of fire, the network will often split into multiple disjoint segments, and its services becomes limited, so it is very important to repair the network.In order to make the work more energy balance, we propose a novel mobile sink path-planning strategy. The sink path-planning strategy computes the location of the sink node based on both the residual energy of cluster heads and the distance between cluster heads. Then we use the ant colony algorithm to optimize the path of the sink node which reduces the moving distance of the sink node. The simulation results showed that the strategy proposed could effectively improve the energy balance of the network and reduce the moving distance of the sink node.In addition, a network repair solution is proposed for the large-scale distributed network to restore the connectivity among disjoint segments by employing the least number of relay nodes. The novel solution selects four nodes as the access points of the network segment, and it connects the segments using the best access points based on the least distance between access points. And then after information exchange between leading relay nodes, we then get the location of relay nodes and achieve the optimization of the number of relay nodes depending on the minimum spanning tree algorithm. The simulation results showed that the new solution not only minimized the number of relay nodes, but also reduced the computing time of the network-repairing.