PON Time Synchronization Using Shared ONU Equalization Delay
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Solution Overview
Problem
In passive optical networks (PONs), non-low-delay ONUs cannot perform low-delay ranging, and existing time synchronization methods fail to account for local time variation parameters of ONUs, leading to incompatibility and synchronization failures when different ONUs access the same branch optical fiber.
Innovation Solution
A method for time synchronization that involves acquiring and configuring equalization delays and response times for ONUs through the OLT, ensuring that the equalization delays of different ONUs accessing the same branch optical fiber are matched, thereby improving compatibility and synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the OLT calculates equalization delay without considering local time variation parameters of ONUs, then the calculation process is simple, but time synchronization fails and uplink data collisions occur
Solution Approach 1:
The patent changes the parameter set used in equalization delay calculation by incorporating local time variation parameters (response times) of ONUs. The OLT obtains response times from multiple ONUs and uses these parameters to calculate a comprehensive equalization delay that accounts for local time variations, thereby achieving reliable time synchronization while maintaining calculation simplicity.
Solution Approach 2:
The patent creates a universal equalization delay value that can be applied to multiple ONUs accessing the same branch optical fiber. By incorporating local time variation parameters into the calculation, the resulting equalization delay becomes universally applicable across different ONU types (low-delay and non-low-delay ONUs), enabling one ONU to reuse the ranging result of another without data collisions.
2Measurement precision
If the OLT uses dedicated ranging results for each ONU, then ranging accuracy is high, but compatibility among different ONUs accessing the same branch fiber is poor
Solution Approach 1:
The patent modifies the ranging calculation by incorporating local time variation parameters (response times) of multiple ONUs. This parameter enhancement transforms the dedicated ranging result into a compatible ranging result that can be reused by different ONU types while maintaining ranging accuracy. The response time parameter acts as a correction factor that accounts for local time variations.
Solution Approach 2:
The patent introduces response time as an intermediary parameter that bridges the gap between different ONU types. By using response times of multiple ONUs in the equalization delay calculation, the system creates a intermediary reference that enables both low-delay and non-low-delay ONUs to access the same branch fiber with proper time synchronization, achieving compatibility without sacrificing ranging accuracy.
3Measurement precision
If the OLT configures different equalization delays for different ONUs, then time synchronization is precise, but system complexity increases
Solution Approach 1:
The patent achieves precise time synchronization through a single universal equalization delay configuration that applies to all ONUs accessing the same branch optical fiber. By incorporating local time variation parameters into the calculation of this universal delay value, the system eliminates the need to configure different equalization delays for different ONU types, thereby maintaining precision while reducing configuration complexity.
Solution Approach 2:
The patent merges the equalization delay configuration into a single unified value that accounts for local time variations of multiple ONUs. Instead of separately configuring delays for low-delay and non-low-delay ONUs, the system combines response time parameters from multiple ONUs to calculate one comprehensive equalization delay that ensures precise time synchronization for all ONUs, simplifying the configuration process.
Data Source
AI summary
A time synchronization method for a passive optical network, and an electronic device and a storage medium are disclosed. The method may include acquiring a first response time from a first optical network unit (ONU); performing a ranging calculation to the first ONU to acquire a first equalization time delay; generating an equalization delay configuration message according to the first response time and the first equalization delay; and sending the equalization delay configuration message to a second ONU to configure a second equalization delay for the second ONU; where the first ONU and the second ONU access the same branch optical fiber.