A Design Of Time Synchronization Protocol Based On Dynamic Path And Variable Period

In order to solve the problems of large-scale wireless sensor networks time synchronization,such as serious accumulation of multi-hop errors,frequent changes of clock frequency,and high energy consumption of nodes,a time synchronization protocol based on dynamic path and variable period(TSP-DPVP)is proposed in this thesis.The network topology structure of clustering is adopted,which can not only reduce the maximum synchronous hops of the network,but also improve the network synchronization accuracy.In the inter-cluster synchronization phase,a multi-hop synchronization mechanism based on dynamic paths is adopted.In each round of synchronization,the neighboring cluster head nodes are selected as reference nodes based on the performance parameters of the number of synchronization hops and clock frequency offsets.By dynamically selecting the synchronization path,multi-hop cumulative error can be effectively reduced.In the intra-cluster synchronization phase,a variable-period synchronization mechanism is used.Through the modeling and analysis of the infra-cluster synchronization errors,the relationship between the frequency deviation change rate and the synchronization period can be determined,and the next synchronization interval can be updated according to the frequency deviation change and the set maximum synchronization error.It can not only meet the requirements of synchronization accuracy,but also extend the resynchronization period,reduce the transmission of synchronization messages,and save energy.Finally,simulation experiments of the TSP-DPVP synchronization scheme are performed on the NS-2 platform,which verify the feasibility of the TSP-DPVP protocol in improving the synchronization accuracy while effectively reducing the energy consumption.