PON ONU Ranging with Segmented Quiet Windows for Low Registration Delay
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Solution Overview
Problem
Existing PON systems face excessive delay due to large quiet windows during ONU registration, which cannot meet the low-delay demands of services like virtual reality and 5G wireless services.
Innovation Solution
The method involves opening multiple small, predetermined quiet windows for ONUs, allowing them to send uplink signals with low rate and low optical power, and calculating distance based on signal arrival times to minimize delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a large quiet window is opened during ONU registration, then all ONUs within the maximum distance range can be registered, but the registration delay becomes excessive and cannot meet low-delay service requirements
Solution Approach 1:
The patent divides the single large quiet window into multiple small quiet windows, each corresponding to a specific distance range from the OLT. Instead of opening one quiet window that covers the entire maximum distance range (causing excessive delay), the system segments the registration process into multiple phases, with each phase handling ONUs within a specific distance interval. This segmentation reduces the time each ONU waits for registration while maintaining comprehensive coverage.
Solution Approach 2:
The patent dynamically adjusts the quiet window configuration based on the actual distribution of ONUs. The OLT determines the maximum distance range based on actual registration needs and dynamically opens appropriate数量的 small quiet windows. This dynamic approach allows the system to adapt to different scenarios - whether ONUs are concentrated near the OLT or distributed across the full distance range - optimizing both coverage and delay performance.
2Loss of time
If multiple small quiet windows are opened for different distance ranges, then registration delay is reduced, but the system complexity increases
Solution Approach 1:
The patent implements a self-service mechanism where the OLT autonomously determines the maximum distance range based on actual registration requests and automatically calculates the appropriate number and positioning of small quiet windows. The system does not require manual configuration or complex external control - the OLT itself performs the optimization by monitoring registration needs and adjusting the quiet window strategy accordingly. This self-service approach reduces operational complexity while maintaining optimal performance.
3Ease of operation
If quiet windows are opened for ONU registration, then uplink bandwidth is allocated for registration signals, but data transmission efficiency is impacted due to bandwidth occupation
Solution Approach 1:
The patent extracts the registration function from the general data transmission bandwidth by dedicating specific small quiet windows exclusively for registration signals. Instead of allowing registration traffic to compete with data traffic for bandwidth resources, the system separates these functions temporally and spectrally. The small quiet windows are specifically allocated for registration purposes only, while the remaining uplink bandwidth continues to serve data transmission without interruption. This extraction minimizes the impact on overall data transmission efficiency.
Solution Approach 2:
The patent employs periodic action by opening small quiet windows at specific intervals rather than continuously occupying bandwidth for registration. The quiet windows are opened only when needed for ONU registration, and closed otherwise to allow full data transmission. This periodic approach ensures that registration functionality is maintained while maximizing data transmission efficiency during non-registration periods.
Data Source
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AI summary
Provided are a ranging method and a communication method for an optical network, an Optical Line Terminal (OLT), an Optical Network Unit (ONU), and an optical network system. The OLT sends a broadcast message to the ONU, the broadcast message being used to indicate an uplink bandwidth allocated to the ONU. The OLT opens a quiet window for the ONU in a predetermined region. The OLT receives an uplink signal sent by the ONU at the quiet window.