Multi-Master Clock Synchronization with Drift Compensation
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Solution Overview
Problem
In computer networks, especially in time-sensitive applications, synchronizing master and slave clocks is challenging due to differences in clock characteristics such as frequency drift and granularity, leading to intolerable clock deviations in industrial and automotive systems.
Innovation Solution
A method for synchronizing master and slave clocks by receiving information about remote times from multiple master clocks, calculating transmission delays and frequency drift compensations, and using IEEE standards like IEEE 802.1 AS-2011 and IEEE 1588-2008 to establish a reliable and robust time synchronization mechanism, where slave clocks are adjusted based on current times and transmission characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If slave clocks are synchronized to multiple master clocks with different time scales, then the reliability and robustness of time synchronization is improved, but the complexity of calculating transmission delays and frequency drift compensations increases
Solution Approach 1:
The synchronization process is segmented into distinct components: receiving remote time information from multiple master clocks, calculating transmission delays separately for each master clock, computing frequency drift compensations independently, and then integrating these results to determine the local time. This segmentation allows each sub-task to be handled independently, improving reliability while managing complexity through modular processing.
Solution Approach 2:
The method performs preliminary calculations of transmission delays and frequency drift compensations before final time synchronization. By pre-calculating these parameters based on received remote time information and current time differences, the system prepares compensation values in advance, ensuring reliable synchronization while organizing complex calculations into a structured sequence that reduces overall system complexity.
2Measurement precision
If transmission delays and frequency drift compensations are calculated for each master clock, then the measurement precision of time synchronization is improved, but the quantity of synchronization messages and network traffic increases
Solution Approach 1:
The method merges multiple synchronization operations into a unified process. Instead of treating each master clock synchronization independently, the system combines the reception of remote time information, delay calculations, and frequency drift compensations into a single integrated synchronization cycle. This merging reduces the total number of separate message exchanges while maintaining precision through comprehensive calculation of all time scale differences.
Solution Approach 2:
The synchronization mechanism is designed with universal applicability to handle multiple master clocks with different time scales. A single synchronization protocol and calculation framework is used that can accommodate any number of master clocks, eliminating the need for separate specialized procedures for each master clock. This multi-functional approach maintains measurement precision while reducing network traffic by avoiding redundant message types.
3Ease of operation
If IEEE 802.1 AS and IEEE 1588 standards are used for synchronization, then the ease of operation and standardization is improved, but the device complexity for implementing multiple compensation calculations increases
Solution Approach 1:
The method uses standardized synchronization messages as intermediaries that carry remote time information between master and slave clocks. These standardized messages, defined by IEEE 802.1 AS and IEEE 1588, serve as a common language that simplifies operation and integration. The intermediary messages encapsulate the necessary time scale information, allowing the complex compensation calculations to be performed systematically without requiring custom proprietary protocols, thus easing operation while managing implementation complexity through standardization.
Data Source
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AI summary
The invention relates to a system and corresponding method of synchronizing master and slave clocks in a computer network, comprising receiving, by a local network node (102), information about a first remote time (t1rel) of a first master clock, receiving, by the local network node (102), information about a second remote time (t1abs) of a second master clock, wherein a first slave clock of the local network node (102) is synchronized to the first master clock, and a second slave clock of the local network node (102) is synchronized to the second master clock, wherein a first time (trel) for the first slave clock is determined depending on a current time (t5r) of the first slave clock, information about the first remote time (t1rel), information about a first delay (Tlink_rel) characterizing a first transmission time for transmitting the first remote time (t1rel) to the local network node (102), and a first compensation (rrel) for a first frequency drift between the first master clock and the first slave clock, a second time (tabs) for the second slave clock is determined depending on the current time (t5r) of the first slave clock, information about the second remote time (t1abs), information about a second delay (Tlink_abs) characterizing a second transmission time for transmitting the second remote time (t1abs) to the local network node (102), and a second compensation (rabs) for a second frequency drift between the second master clock and the first slave clock.