Boundary Clock Time Synchronization Failure Detection
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Solution Overview
Problem
In time synchronization systems using the Precision Time Protocol (PTP), failures in the grand master clock's GNSS antenna or the clock itself, or transmission paths can lead to significant deviations in time synchronization, causing incorrect time distribution to lower-level devices, potentially resulting in system failures or communication issues.
Innovation Solution
A time synchronization device and method that calculate the offset and transmission delay time between devices, determining the occurrence location of failures and stopping synchronization with higher-level devices if a failure is detected, using units such as offset calculation, transmission delay time calculation, and determination units to prevent incorrect time propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the boundary clock synchronizes with the grand master clock without failure detection, then time synchronization is maintained, but incorrect time may be propagated to lower-level devices causing system failures
Solution Approach 1:
The patent applies preliminary action by calculating the offset between the boundary clock and grand master clock before time synchronization is established. This pre-calculated offset serves as a baseline for detecting future synchronization failures, allowing the system to identify when the grand master clock provides incorrect time information without requiring complex real-time analysis of synchronization data.
Solution Approach 2:
The patent implements feedback by continuously monitoring the offset between the boundary clock and grand master clock, comparing it against the pre-calculated baseline offset. When the monitored offset deviates beyond a predetermined threshold from the baseline, the system detects a synchronization failure and stops distributing time to lower-level devices, thereby preventing propagation of incorrect time while maintaining system reliability.
2Reliability
If the boundary clock stops synchronization upon detecting failure, then propagation of incorrect time is prevented, but normal time synchronization may be interrupted due to transient issues
Solution Approach 1:
The patent applies partial action by implementing a threshold-based failure detection mechanism rather than absolute failure detection. The system monitors offset deviations and only stops synchronization when the deviation exceeds a predetermined threshold, allowing for transient variations and noise in the synchronization signal. This prevents over-reacting to minor fluctuations while still detecting genuine synchronization failures, thus maintaining productivity while ensuring reliability.
3Measurement precision
If the system monitors offset continuously to detect failures, then synchronization accuracy is maintained, but computational overhead and processing time increase
Solution Approach 1:
The patent reduces processing energy consumption by performing the computationally intensive offset calculation once during system initialization or when synchronization parameters change, rather than continuously recalculating it. This pre-calculated baseline offset is then used for simple comparison operations during continuous monitoring, significantly reducing the computational overhead and energy consumption of ongoing failure detection while maintaining measurement precision.
Data Source
AI summary
A boundary clock (100) as a time synchronization device according to the present disclosure includes: an offset calculation unit (102) that calculates an offset that is a difference between device internal time of a higher-level device and device internal time of an own device; a transmission delay time calculation unit (103) that calculates a transmission delay time of a packet transmitted and received between the higher-level device and the own device; and a determination unit (111) that determines an occurrence location of a failure in time synchronization with the higher-level device on the basis of the offset and the transmission delay time, and stops synchronization of device internal time of a lower-level device with the device internal time of the own device in a case where it is determined that the occurrence location of the failure is the higher-level device.