Optical Time Transmission Device for Asymmetric Path Synchronization
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Solution Overview
Problem
Current time synchronization technologies, such as Precision Time Protocol (PTP), face errors due to upstream and downstream asymmetry in optical transmission paths, leading to synchronization errors and inefficient wavelength band utilization, which increases the number of required transponders.
Innovation Solution
A time transmission device with an optical transmission unit and a time synchronization unit that uses delay measurement signals to correct time deviations, manages propagation delays, and generates intermittent signals to multiplex time information and communication data, allowing for efficient wavelength sharing and reduced transponder requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple wavelengths are used for time synchronization signal transmission, then time synchronization accuracy is improved, but wavelength band utilization efficiency deteriorates
Solution Approach 1:
The patent combines time synchronization signals and communication data signals into a single optical wavelength channel by using optical burst switching technology. Multiple signals that were previously transmitted on separate wavelengths are now multiplexed and transmitted together, improving wavelength band utilization while maintaining synchronization accuracy through dedicated burst formatting and timing mechanisms
Solution Approach 2:
The patent makes a single optical wavelength channel serve multiple functions by simultaneously transmitting both time synchronization signals and communication data. The optical transmission system is designed to handle different signal types (synchronization bursts and data bursts) on the same wavelength, making the wavelength band universally useful for both synchronization and communication purposes
2Reliability
If separate wavelength channels are allocated for time synchronization and communication data, then time synchronization reliability is improved, but device complexity increases
Solution Approach 1:
The patent merges the previously separate wavelength channels for synchronization and data into a single shared channel. By using optical burst switching with dedicated burst formats and timing, the system maintains synchronization reliability while eliminating the need for separate transponders, thereby reducing device complexity
Solution Approach 2:
The patent uses burst copying mechanisms where time synchronization bursts are replicated and distributed to multiple nodes through the same optical channel. The burst switching fabric copies synchronization bursts to appropriate destinations while maintaining timing relationships, eliminating the need for dedicated wavelength channels at each node
Data Source
AI summary
An optical transmission device of each node simultaneously sends a plurality of signals having different wavelengths as delay measurement signals to a transmission path. The optical transmission device determines a delay value that reflects a propagation delay calculated based on an arrival time difference between a plurality of wavelengths in a signal received from another node, and determines a waiting time amount based on the delay value and the propagation delay. The optical transmission device notifies the other node of the delay value. Each optical transmission device outputs the received signal from the other node with a delay of the waiting time amount. The optical transmission device generates an optical intermittent signal obtained by selecting and multiplexing any of time information, the delay measurement signal, and communication information. A reception side extracts a desired multiplexed signal from the received optical intermittent signals.