The Study Of Time Synchronization Protocol For Wireless Sensor Network

Wireless sensor network (WSN) has received high attention in the last few years. Time synchronization is an important support for wireless sensor network. Many aspects of WSN, such as protocols designing, network management, nodes' cooperation, object tracking and date fusion, all need the network time keep the same.The errors of these different protocols are studied in detail based on the analyses and classify of several existing time synchronization protocols and the decomposition of the message delivery delays ; in order to meet the accuracy requirement of wireless sensor network and take account of saving energy as soon as possible, reference-broadcast time synchronization protocol based on hiberarchy (RBTSH) is proposed; the module of RBTSH is designed and added to the Network Simulator(NS), evaluating the performance of RBTSH in the terms of average accuracy of multi-hop time synchronization and the total number of messages exchanged with the designed script.In RBTSH protocol, all nodes in the network are assigned a level when they receive the first level-discovery packet to reduce energy consumption and network congestion caused by flooding. Each parent node has a special child node. Two-way message exchange and reference-broadcast are used to achieve network-wide synchronization.The study and simulation results show that the new time synchronization protocol (RBTSH) can meet the accuracy requirement of wireless sensor network, and needs less transmission messages, can save energy resource efficiently. So RBTSH protocol can be used in the applications with low precision demands but long lifetime requirement.