Research On Multi-objective Optimization Of ZigBee Network Routing Protocol

Wireless sensor networks(WSNs) is a kind of Ad-hoc network that is formed by many isomorphic sensor nodes distributed in an area randomly. The main functions of the WSNs are data collection and terminal controlling. At present, ZigBee technology, which has the characteristics of low rate, low cost and low power consumption, is the most widely used in the WSNs. Since the nodes in ZigBee networks are usually battery-powered, the researches on ZigBee are concentrated on reducing energy consumption of single node and prolong the life time of a network. In addition, how to guarantee the quality of service (QoS) is becoming more and more important.This thesis introduces the details of the ZigBee technology at first, then proposed some improvements to ZigBee:(1) In the stage of routing discovery, the nodes use the routing discovery strategy which is based on restricting the RREQ broadcast. Node which received the RREQ will determine whether the node is located between the source node and the destination node through calculating the depth of the destination node. If so, the node will broadcast the RREQ, on the contrary, it will not broadcast the RREQ. This strategy can restrain the minimum route, eliminate the broadcast storm of RREQ, and improve links quality.(2) In the stage of routing selection, the nodes use the distributed dynamic energy balancing routing strategy. The algorithm introduces backup routing table and local energy balanced routing indicator. When node determine the route, it will calculates the local energy balanced routing indicator when choosing a next hop in the backup routing table in order, and determine which route to choose.(3) The data of the network layer will be classified according to different QoS requirements. The different data have different priority, and use the different routes. Through data classifying, the management of network layer becomes more precise, and the link are used efficiently, the loads and energy are distributed more balanced.At last, the thesis simulates the algorithms via OPNET modeler. The result of simulation indicates that the improvements to ZigBee routing algorithm can improve the QoS of the network effectively, balance the distribution of the loads and energy, and prolong the life time of the whole network.