Service Board Compensation for Time Path Asymmetry
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for compensating for time path asymmetry in fiber links within mobile communications systems are labor-intensive, require on-site measurements, and are inefficient, especially when fibers change or are deployed in unsuitable locations, such as basements or metro stations, leading to poor operability and high workloads.
Innovation Solution
A method and device that utilize service board units and compensation units to calculate and automatically compensate for time path delays by receiving and sending time stamps through fibers, calculating path delays, and using the difference as a compensation time value to correct for asymmetry, thereby enabling efficient and real-time correction of time tracking offsets without the need for node-by-node measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS is used to perform node-by-node measurement and compensate fibers with asymmetric value, then time synchronization precision is improved, but workload and operational complexity increase significantly
Solution Approach 1:
The system segments the time path compensation function into dedicated compensation units that are distributed at different nodes. Each compensation unit independently calculates and compensates for time path asymmetry on its local segment, eliminating the need for centralized GPS-based node-by-node measurement while maintaining synchronization precision.
Solution Approach 2:
The compensation units enable each node to automatically measure and compensate for its own time path asymmetry using local time stamps and path delay calculations. This self-service mechanism eliminates the need for external GPS equipment and manual on-site measurements, significantly reducing operational workload while maintaining measurement precision.
2Measurement precision
If on-site measurement is performed for each node using GPS, then fiber asymmetry is accurately measured, but measurement can be carried out only at suitable locations
Solution Approach 1:
The system replaces the mechanical GPS-based measurement system with an electronic time stamp-based measurement mechanism. Time stamps are embedded in data packets transmitted through the fiber links, allowing asymmetry measurement to be performed electronically at any deployment location without requiring GPS satellite visibility, thus enabling deployment in basements, metro stations, and other GPS-denied environments.
Solution Approach 2:
Time stamps serve as an intermediary mechanism that carries timing information through the fiber links. By using time stamps embedded in data packets as mediators, the system can measure fiber asymmetry without direct line-of-sight to GPS satellites, enabling measurements at locations where GPS antennas cannot be deployed.
3Reliability
If manual measurement and compensation is performed for each node, then time path asymmetry is corrected, but measurement must be repeated whenever fiber is disconnected
Solution Approach 1:
The compensation units continuously perform time path asymmetry measurement and compensation using ongoing data packet transmissions. Instead of performing discrete manual measurements that must be repeated after fiber disconnections, the system maintains continuous automatic measurement and compensation, ensuring time synchronization reliability is maintained throughout fiber lifecycle changes without requiring repeated manual interventions.
4Measurement precision
If node-by-node GPS measurement is used, then asymmetric value is obtained for compensation, but the process is labor-intensive and inefficient
Solution Approach 1:
Each compensation unit automatically performs local time path asymmetry measurement using time stamps from passing data packets and calculates its own compensation value. This self-service approach eliminates the need for external measurement teams to manually measure each node, maintaining measurement precision while dramatically improving productivity by enabling parallel automatic measurements across all nodes simultaneously.
Data Source
Figure 1~2
Figure 3~5
Figure 6
AI summary
Embodiments of the present invention relate to a method and a device for compensating for a time path. In the embodiments of the present invention, on the basis of not changing the implemented 1588 synchronization architecture, a compensation unit is added on a service board unit, the compensation unit calculates a compensation time value for asymmetrical reception and transmission of fiber links and transfers the compensation time value into the service board unit, and the service board unit implements automatic compensation according to a port status. The method and the device for compensating for a time path according to the embodiments of the present invention may implement automatic compensation for receiving and sending fiber links without manually testing the asymmetry of links node by node, so that the embodiments of the present invention can be widely applied in time synchronization networks.