Research On Time Compensensation Technology Of Network Timing System

With the rapid development of modern technologies such as 5G and high-precision communications,network timing as a key supporting technology has received extensive attention.Distributed measurement,algorithm scheduling,high-frequency trading,and many other emerging applications have also rapidly increased the demand for network timing service,which puts forward higher requirements for the timing accuracy of the existing network timing service system.The Precision Time Protocol(PTP)is currently a widely used timing protocol,which has achieved a huge breakthrough in timing accuracy from milliseconds to sub-microseconds.However,due to the asymmetric uplink and downlink delays in the actual network,the calculation result of the PTP time offset is inaccurate,and the timing accuracy is therefore limited.The phase offset estimation method can use the prior information of the timing network and the time stamp of the synchronization data packet to estimate the offset of the slave clock.It does not require hardware support and does not require changes to the PTP to provide new network timing.The idea is to combine time offset estimation with time compensation technology to improve timing accuracy.In order to solve the problem that the network timing accuracy is restricted by the asymmetric delay,this paper has carried out research on the time compensation technology of the network timing system.The specific content is as follows:(1)Investigate related research on time service and time compensation technology.Summarized common timing technologies and network timing;introduced the basic concepts of PTP and the best master clock algorithm;conducted research on related research on time compensation technologies,and summarized and compared the characteristics and performance indicators of each technology.(2)Combining the asymmetric time delay model,carry out research on the time offset estimation method.Discuss the reasons for the asymmetric delay and propose corresponding solutions;model the network delay;conduct model analysis on common time offset estimation methods including phase offset estimation methods and traditional offset estimation methods;build In the test environment,the performance of different methods is compared and tested in a variety of scenarios such as cross background flow,parallel background flow and different loads.The experimental results show that the K model of the phase shift estimation method has better performance,and it is selected as The phase offset estimation method used for time compensation.(3)Propose the time compensation method of the network timing service system and realize the time compensation.A time compensation method for network timing system is proposed,which separates the time transmission and compensation of network timing,and adopts cost-effective centralized compensation methods to improve timing accuracy;build an environment to achieve network timing system time compensation,and the average time error after compensation is reduced to the original four.About one part,the effectiveness of time compensation is proved;for the problem of low slave clock stability,the time compensation algorithm based on PID control algorithm,TD control algorithm and Kalman filter is proposed,and the application effects of the three algorithms are carried out.In summary and comparison,the experimental results show that the standard deviation of the time error after applying the time compensation algorithm is reduced to about one-sixth of the original,which proves that the time compensation algorithm can improve the stability of the slave clock.