Multi-Master Clock Synchronization for Uniform Network Timestamps
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Solution Overview
Problem
Current time synchronization methods in networks, particularly those using the IEEE PTP standard, face challenges in ensuring uniform clock synchronization across different clocks, leading to potential errors in timestamp accuracy and event sequencing due to differences in clock rates and frequencies, especially when dealing with multiple clocks for working time and global time.
Innovation Solution
The method involves using synchronization messages from multiple masters to adjust the clock rate and time difference of slave clocks, allowing both clocks to run at the same speed without time jumps, and utilizing the clock rate of one clock to set the other, ensuring synchronization through both synchronization and syntonization processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If each clock is synchronized independently with its own master, then time synchronization is achieved for each clock, but clock rates differ between clocks leading to timestamp errors
Solution Approach 1:
The patent merges the synchronization of multiple clocks by making the second clock dependent on the first clock's synchronized time. Instead of independent synchronization, the second clock uses the first clock's time as its reference, ensuring both clocks maintain the same rate and remain synchronized, thereby preventing timestamp errors and sequencing issues.
Solution Approach 2:
The first clock acts as an intermediary between the first master and the second clock. The second clock synchronizes with the first clock rather than directly with the second master, creating a hierarchical synchronization structure that ensures uniform clock rates across all clocks while maintaining accuracy relative to their respective masters.
2Measurement precision
If clock rate is adjusted for synchronization, then time difference is reduced, but clock frequency differences cause continuous drift
Solution Approach 1:
The system continuously monitors the time difference between clocks and adjusts the second clock's rate based on feedback from the first clock. This closed-loop control ensures that any drift caused by frequency differences is corrected in real-time, maintaining both synchronization accuracy and long-term stability without requiring large rate adjustments.
3Reliability
If multiple masters send synchronization messages, then comprehensive time coverage is achieved, but clock rate differences cause synchronization errors
Solution Approach 1:
The patent introduces a hierarchical dimension to the synchronization structure. Instead of parallel synchronization from multiple masters, it creates a layered approach where the second clock synchronizes with the first clock (which synchronizes with the first master), and the second master's messages are processed relative to this hierarchical structure. This resolves the conflict by maintaining accuracy through the hierarchy while preserving comprehensive time coverage.
Data Source
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AI summary
The present invention describes a method for time synchronization in a network (1), wherein the network (1) contains a plurality of masters (M1, M2) and at least one slave (S). The at least one slave (S) receives synchronization messages (D1, D2) via the network (1) from the plurality of masters (M1, M2) for time synchronization of a first clock (3) and a second clock (5) of the slave (S). A first master (M1) sends a first synchronization message (D1) with a first timestamp (t1) to the at least one slave (S) for time synchronization of the first clock (3).At least one slave (S) compares the first timestamp (t1) of the first synchronization message (D1) with the current time of the first clock (3), determines a clock rate (rA) and a time difference (dt1) between the first clock (3) and the first master (M1) based on this comparison, and performs a time synchronization, causing the first clock (3) in the slave (S) to run with the synchronized time. A second master (M2) sends a second synchronization message (D2) with a second timestamp (t2) to the at least one slave (S) for time synchronization of the second clock (5), using the clock rate (rA) of the first clock (3) to set a clock rate (rG) for the second clock (5) by matching the clock rate (rA) of the first clock (3).The at least one slave (S) then compares the second timestamp (t2) of the second synchronization message (D2) with the second current time of the second clock (5) and, based on this comparison, determines a time difference (dt2) of the second clock (5) to the second master (M2) and then performs a time synchronization such that the second clock (5) in the slave (S) also runs with the synchronized time.