Power-saving And Lifetime-aware Data Gathering Algorithms For Wireless Sensor Networks

In recent years, with the rapid development of chip, communication and sensor technology, Wireless Sensor Networks(WSNs) have been widely used in many fields. WSNs is made up of a large number of nodes that integrated sensor unit, data-processing unit and communication unit. The nodes can self-organize into a wireless network. They are used to sense, collect and process all kinds of information from the surveillance, then send to the data receiver. WSNs can be widely applied to military defense, environmental detection, antiterrorism and health-care etc.The nodes of WSN run on battery, and usually are working at somewhere bad or even hostile. So, the supply of energy to nodes is restricted. How to save energy, improve network lifetime of the network is the key issue in WSNs research.In the paper, we emphasize on data gathering problem. Our main purpose is extending network lifetime. Network lifetime is closely related to the amount of energy used by nodes, once some of the key nodes run out of energy, the network will not be able to work. The energy of WSNs is mainly used on data transmission, and the amount of energy used lies on the distance of two neighbor nodes(the longer the distance is, the more energy it needs). In order to save energy, it adopts a way of short-distance and multi-hop transmission. However, multi-hop transmission will cause a delay of data transfer. Multi-hop transmission will overbalance the energy consumption of each nodes. The closer nodes to base station, the faster they consume energy, because they have more data to transmit. A lifetime-aware data gathering algorithm(LDGA) is proposed in this dissertation. LDGA takes into account both of the remain energy and energy consumption for data transmitting among nodes, and construct a data gathering tree which can prolong network lifetime. Numeric experimental results show that LDGA algorithm can prolong network lifetime evidently.In order to balance the energy consumption of node and data transmission delay, an energy-aware data gathering algorithm is proposed, referred to as diffluent traffic routing algorithm (DTRA). The DTRA algorithm adopts a optimization model to improve the outgoing traffic proportion of each node, where genetic algorithm is used to find the solution of the optimization problem. The DTRA algorithm can balance network lifetime and the number of packet hops. Numeric experimental results show that the DTRA is able to prolong network lifetime considerably and keep packet hops in a relatively low level. Further, it outperforms some well-known routing algorithm in terms of network lifetime.Research achievement will certainly make data gathering of WSNs low in energy and high in network lifetime. it can apply to environment detection, environmental protection,disaster presentiment etc.