Research On Energy-Efficient Routing Mechanism And Algorithm For Wireless Sensor Networks

In recent years, some new low cost and multi-function micro-sensor nodes are produced along with the rapid development of Micro-Electro-Mechanical Systems, low energy-consumption electro-devices and wireless communication techniques. And in the future, wireless sensor networks that consist of these equipments will probably bring huge influence to almost all of the industrial fields and people's daily life. However, as wireless sensor nodes are characterized by limited energy availability, low memory and reduced processing power, energy efficiency is a key issue in designing the network. Routing mechanism can affect the network's status from the network layer; simple, effective and low energy consumption route becomes an important target of a high performance network. Taking the energy optimization as the goal, this dissertation mainly researches on the cluster-based hierarchical routing protocols, including the communication between nodes in cluster, dynamic foundation of the cluster as well as application-based routing solution.In the dissertation, a new least-hop based routing algorithm is proposed. The network overall uses the cluster-based hierarchical routing mechanism, and in cluster, least-hop based routing model is used for data collection and transmission. This kind of structure fully utilizes the advantage of least-hop route while the nodes is more in cluster, which can make the communication between nodes along with the best route, and can make the information packets in the network least. So long as remember their own hop number and those nodes that are one-hop far away from them, the source nodes can transmit data to their cluster-heads easily. Regarding the nodes that newly join, they can become the member of the network just after they send the registration information to their one-hop neighbors. Then, it achieves the goal of enhancing the network performance and reducing the energy consumption.A new convergence-degree based hierarchical cluster routing algorithm is also proposed here. It takes the node's convergence degree as the basis, and divides the network nodes into clusters, and fully displays the close relationship between the convergent nodes and reduces the network management energy consumption while frequently re-clustering. With this kind of structure, the nodes in same cluster will have more close relationship, and the network will have lower node overlapping between different clusters. In cluster, by using dynamic clustering organization, union with cluster rebuilding and cluster's self-recovery mechanism, the algorithm enables the protocol to have the dynamical equilibrium energy consumption characteristic, which balances the nodes' energy consumption. Between the cluster-heads, multi-hop routing model is used, which can reduce the transmission energy consumption, and then prolongs the lifetime of the network.In the on-demand network environment, a method that a cluster-head distributes energy load evenly among its members is proposed. Cluster-based routing protocol can reduce the nodes' energy consumption to a certain degree, but how to balance the nodes' energy consumption in cluster is still a major problem. By building the chain in cluster, the data can be fully fused while being translated from the source node to cluster-head, and the new route pattern needs less transmission energy. As the agent node of cluster-head, the head of chain shares the cluster-head's work, which reduces the cluster-head's energy consumption. At the same time, the dynamic replacement of chain-head causes the nodes energy consumption more balanced.As wireless sensor network is application-based, a mobile agent routing algorithm in cluster is also proposed, which can resolve the communication problem between mobile nodes and static nodes of the network. It regards the problem that mobile nodes collecting data in cluster along with superior way as a vertex-weighted traveling tourist problem, at the same time expands the mobile proxy based information processing process into the cluster. By using a new approximation algorithm, the cluster-head can get the best route that mobile nodes will along with, and then the mobile proxy will gather the fullest data from the static nodes. The new algorithm gives us the relationship between various essential factors, and enables the successful data transmission between nodes. And union with the dynamic dormancy mechanism, it can reduce the energy consumption.This dissertation mainly researches on the hierarchical routing algorithm of wireless sensor networks. Based on the networks' characteristics and its practical application environments' characteristics, the aim of the work is to resolve the present problems in domain.