Research On Time Synchronization Algorithm For Wireless Sensor Network

Wireless sensor network integrates wireless communication technology,wireless sensor technology and information processing technology,it is widely used in industry,agriculture,medical care,artificial intelligence and other fields.Wireless sensor network is characterized by large number of node,equal status of node and flexible topology.Time synchronization ensures the synchronization of sensor node in wireless sensor network,and is the basis of application technologies such as location,data exchange,node scheduling and node state set.During time synchronization,sensor node repeatedly receive and send time packets,which consumes node energy and reduces node battery working time.It is of great significance to study low-power time synchronization algorithm for the development of wireless sensor network technology.RBS algorithm and TPSN algorithm are typical time synchronization algorithms,both algorithms have good synchronization effect,but there are still have some limitations.In largescale wireless sensor network,RBS algorithm has broadcast synchronization characteristics,and the data exchange capacity increases exponentially,increases the network communication burden.TPSN algorithm uses hierarchical network design to realize node time synchronization.When the network scale increases,the traffic increases and the cumulative error increases,affecting the synchronization accuracy.This thesis combines the advantages of RBS algorithm and TPSN algorithm,and put forward CS-TPSN(Core Node Synchronization-TPSN)algorithm.The network selects the clock node as the core node,stratifies the network according to the communication distance between common node and core node,and select synchronous node in each hop network,and data bidirectional communication is carried out between synchronous node.By selecting synchronization node,the transmission times of data packets are reduced and the network topology between each hop is optimized.In network communication,bidirectional data transmission and broadcast data transmission are combined.When time synchronization data packets are transmitted,except for bidirectional communication between synchronous node and core node,and between synchronous node,other node acquire data packets by broadcast monitoring.The method of combining bidirectional communication and broadcast communication can reduce the time synchronization request times and optimize the data communication mode.The algorithm on the premise of ensuring the accuracy,the network topology and data communication mode are optimized,and the energy consumption of the algorithm is reduced.Modeling and simulation analysis of CS-TPSN time synchronization optimization algorithm are carried out by OPNET.One-hop to seven-hop network model with 50,75,100,125,150,175 and 200 nodes are designed in OPNET.The CS-TPSN algorithm is compared with RBS algorithm and TPSN algorithm to analyze the network performance of synchronization error,running cost and convergence time.Simulation results show that,with the increase of node number and node hop number,CS-TPSN algorithm has low synchronization error,less packet exchange times and fast convergence speed,and achieves the goal of reducing the energy consumption of wireless sensor node.Based on CS-TPSN time synchronization algorithm,an experimental platform is built based on CC2530 chip development board.IAR EW is used as the development environment to design the test scheme.The feasibility and effectiveness of CS-TPSN algorithm are verified,and it has certain application value.