Research And Implementation Of Clock Synchronization Method For High Reliable Real-time Ethernet

The research background of this thesis is a real-time Ethernet communication project,which can be used in asymmetric network.In the real-time network,the transmission of data depends on the time trigger mechanism,which requires a unified time benchmark for the whole network.Keeping the frequency difference and phase difference of each clock in a reasonable range is called clock synchronization.The purpose of this thesis is to design a set of clock synchronization scheme,which is used in the synchronization module of this project,to provide accurate time reference for the network.IEEE 1588v2 protocol provides an efficient clock synchronization scheme for Ethernet field,but its application in real-time asymmetric network environment remains to be studied.To solve this problem,this thesis studies the clock synchronization mechanism of 1588v2 protocol in asymmetric network,and completes the following work:1.This thesis analyzes the maladjustment between 1588v2 protocol and this project,makes some adaptive improvement to 1588v2 standard,and puts forward corresponding solutions.2.In this thesis,the processing method of 1588v2 protocol for asymmetric network is studied,and the reason why the asymmetric communication path is easy to reduce the synchronization accuracy is analyzed,which is verified by simulation.3.Based on the real-time asymmetric network background of this project,the application defects of 1588v2 protocol in this kind of network are demonstrated,and the clock synchronization algorithm which can avoid these defects is proposed and verified by simulation.4.Based on the idea of the above-mentioned improved algorithm,combined with the structural characteristics of four common networks in the project,four corresponding synchronization algorithms are proposed and verified by simulation based on Verilog.In general,the 1588v2 protocol has been extended and applied in real-time network.Through simulation,the application defects of 1588v2 protocol in real-time asymmetric network are verified.The synchronization accuracy of the improved algorithm is higher than that of the original algorithm in 1588v2 protocol.In addition,the synchronization algorithm corresponding to each topology is feasible,and the synchronization accuracy meets the index requirements.The research results of this thesis can be used in the project synchronization module and achieve the expected goal.