Grand Clock Error Signal for Precision Time Distribution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In large networks, the accumulation of clock errors introduced by each boundary clock in the distribution chain leads to unacceptable precision issues, especially in large telecommunication and IP-based systems, where existing methods like PTP do not achieve sufficient precision.
Innovation Solution
A system and method that synchronizes clock regenerators directly to a grand master clock by distributing an additional error signal through the network, calculating and propagating a grand clock error that accounts for each stage's error, effectively eliminating wander accumulation and ensuring precision time distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a chain of boundary clocks is used to distribute the grand master clock reference across a large network, then the network coverage is extended, but the clock error accumulates and precision deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where each boundary clock receives not only timing information from its upstream neighbor but also the grand clock error signal from the grand master clock. This feedback allows each boundary clock to correct its timing based on the actual error relative to the grand master, preventing error accumulation across the network chain and maintaining precision even as network coverage expands.
Solution Approach 2:
The patent segments the error correction function by introducing a separate grand clock error signal that is independently distributed to each boundary clock. Instead of relying on the cumulative error from the chain structure, each boundary clock segment receives direct error information from the grand master, allowing independent correction at each segment and preventing overall error accumulation.
2Device complexity
If each boundary clock synchronizes to its immediate upstream clock, then the synchronization protocol is simplified, but error accumulation occurs across multiple stages
Solution Approach 1:
The patent adds another dimension to the synchronization protocol by introducing a separate grand clock error signal channel. While boundary clocks still synchronize to their upstream clocks (maintaining the simple hierarchical structure), this additional dimension provides direct error information from the grand master to each boundary clock, enabling precision correction without increasing the fundamental synchronization protocol complexity.
3Measurement precision
If the grand clock error signal is distributed to all boundary clocks, then wander accumulation is eliminated, but network traffic increases
Solution Approach 1:
The patent makes the grand clock error signal serve multiple functions simultaneously: it provides precision correction to each boundary clock, enables wander accumulation elimination across the entire network, and can be used by any boundary clock that needs direct reference to the grand master. This multi-functionality justifies the additional network traffic as it delivers high-value information that benefits the entire network rather than just a single node.
Data Source
AI summary
A system and method for synchronizing clocks across a packet-switched network eliminates wander accumulation to enable precision clock distribution across a large network. In addition to standard Precision Time Protocol (PTP) synchronization messages or similar time synchronization messages, each clock regenerator stage receives a grand clock error message from the previous stage, updates this error message with its own stage clock error, and then transmits the updated grand clock error to the next stage. This enables the synchronization algorithm to compensate for the error of the previous stage, effectively locking each clock regenerator stage to the grand master clock directly.