Holdover Calibration for Network Time Sync After Routing Changes
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Solution Overview
Problem
Existing networked systems face synchronization issues due to asymmetrical propagation delays between devices, which are exacerbated by routing changes that disrupt the precision of time transfer protocols.
Innovation Solution
Implement a holdover mode in networked devices to temporarily suspend synchronization during routing changes, measure phase differences, and recalibrate using a new reference value based on holdover timing and time comparison measurements to adapt to new routing paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a calibration of the transmitter and/or receiver is implemented based on the initial relative delay coefficient, then synchronization precision is improved for the initial routing path, but the calibration becomes invalid when routing changes occur, introducing new phase offsets
Solution Approach 1:
The system dynamically adjusts the relative delay coefficient based on detected routing changes. Instead of using a static calibration value, the system continuously monitors routing path variations and updates the delay coefficient accordingly, allowing the synchronization system to adapt to changing network conditions while maintaining precision
Solution Approach 2:
The system implements a feedback mechanism where routing changes are detected and trigger recalculation of the relative delay coefficient. The detected routing information feeds back into the calibration process, allowing the system to automatically adjust and maintain synchronization precision despite network topology changes
2Duration of action of stationary object
If continuous synchronization is maintained during routing changes, then time transfer continuity is preserved, but phase offsets are introduced due to asymmetrical propagation delays in new routing paths
Solution Approach 1:
The system performs preliminary detection of routing changes before they fully impact synchronization. By detecting routing variations in advance, the system can prepare appropriate calibration adjustments, recalculating the relative delay coefficient proactively to prevent phase offsets before they occur
Solution Approach 2:
The system changes the calibration parameter (relative delay coefficient) in response to detected routing changes. When a routing change is detected, the system updates the delay coefficient to match the new path characteristics, thereby maintaining both continuity and precision through parameter adaptation
3Measurement precision
If routing changes are detected and calibration is updated, then synchronization precision is maintained, but system complexity increases due to additional detection and recalibration mechanisms
Solution Approach 1:
The system performs self-calibration by automatically detecting routing changes and adjusting its own calibration parameters without external intervention. The transmitter or receiver autonomously monitors routing path variations and recalculates the relative delay coefficient, eliminating the need for complex external calibration infrastructure
Solution Approach 2:
The routing detection and calibration update mechanisms are integrated into the existing time transfer protocol infrastructure. The same communication channels and processing units used for time synchronization are also utilized for routing change detection and calibration management, reducing overall system complexity through multi-functionality
Data Source
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AI summary
Networked system having at least a first device, a second device being connected to the first device, at least the second device comprises at least one holdover module (208) so that the second device could operate in a first mode wherein the second device is synchronized with the first device and a second mode wherein the synchronization between the first device and the second device is interrupted. Associated calibration process.