Communication Device Clock Synchronization for Cascaded Networks
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Solution Overview
Problem
Existing network synchronization methods, such as PTP, face challenges in maintaining high clock accuracy across cascaded networks due to inconsistencies and errors caused by unrelated clock counters, leading to biased residence time calculations.
Innovation Solution
A communication device with at least two communication ports, each associated with a respective clock, computes and synchronizes the offset between these clocks to improve clock accuracy and reliability in residence time calculation, using methods like Pulse Per Second (PPS) signal synchronization and clock adjustment processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If independent clocks are used at each communication port, then device complexity is reduced and ease of operation is improved, but clock synchronization accuracy and residence time calculation precision deteriorate
Solution Approach 1:
The patent merges the clock systems of multiple communication ports by introducing a master clock that synchronizes all port clocks. The master clock generates a reference signal that is distributed to all ports, ensuring they use a unified time base. This resolves the contradiction by maintaining the simplicity of having clocks at each port while eliminating the precision issues of independent clocks through centralized synchronization.
Solution Approach 2:
The master clock acts as an intermediary between the independent port clocks and the external PTP grand master clock. It receives synchronization from the external source and distributes it to all ports, mediating the time reference to ensure consistency across all communication ports while maintaining their operational independence.
2Reliability
If PTP synchronization protocol is implemented, then network time synchronization is achieved, but clock offset and frequency offset errors persist due to unrelated clock counters
Solution Approach 1:
The patent combines all port clocks under a single master clock that shares the same time counter. This merging eliminates the fundamental issue of unrelated clock counters that causes offset and frequency offset errors in PTP synchronization. By using a unified time base for all ports, the system achieves both network synchronization reliability and high clock synchronization accuracy.
3Measurement precision
If a single time system is shared across all ports, then residence time calculation accuracy is improved, but device complexity increases
Solution Approach 1:
The patent segments the time system into two distinct parts: a shared master clock that provides the common time base for accurate residence time calculation, and independent port clocks that maintain operational simplicity. This segmentation allows the system to enjoy the accuracy benefits of a unified time system without the complexity of fully integrating all clock functions into a single unit.
Data Source
AI summary
A communication device comprising at least one communication port called reception port and another communication port called forward port, each communication port being associated with a respective clock, the communication device being further configured for computing an offset between the respective clocks associated with the reception and forward ports, and synchronizing the respective clocks based on the computed offset.