Ranging Method for Optical Network Latency Reduction
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Solution Overview
Problem
Passive Optical Networks (PON) face challenges in meeting low latency requirements due to the need for large silent windows during ONU registration, which delays low latency services like virtual reality and 5G wireless services.
Innovation Solution
A ranging method that performs coarse ranging followed by fine ranging with a smaller silent window, allowing for accurate distance calculation and registration of ONUs, thereby reducing latency and meeting low latency service requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large silent window is used during ONU registration to ensure accurate ranging, then measurement precision is improved, but service latency increases
Solution Approach 1:
The patent segments the ranging process into two distinct phases: coarse ranging and fine ranging. Coarse ranging uses a larger silent window to achieve initial distance estimation with lower precision requirements, while fine ranging uses a smaller silent window to achieve higher precision. This segmentation allows the system to balance between measurement precision and service latency by performing accurate ranging only when necessary.
Solution Approach 2:
The patent performs coarse ranging as a preliminary action before fine ranging. By first obtaining an approximate distance measurement through coarse ranging with a larger silent window, the system can then perform fine ranging with a smaller silent window, knowing the expected arrival time range. This preliminary action reduces the overall latency impact while maintaining ranging accuracy.
2Reliability
If a large silent window is used during ONU registration to capture all possible signals, then reliability is improved, but productivity decreases
Solution Approach 1:
The patent divides signal capture into two stages: coarse ranging stage with large silent window for reliable initial signal capture, and fine ranging stage with smaller silent window for precise measurement. This segmentation ensures that signals are reliably captured in the first stage, then allows faster processing in the second stage, improving overall system productivity.
Solution Approach 2:
The coarse ranging process serves as a preliminary action that identifies and captures candidate ONU signals before the fine ranging process. This preliminary signal capture ensures reliability by using a larger window, while the subsequent fine ranging with smaller window improves productivity by reducing the time needed for precise measurement.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces service latency by minimizing the silent window duration, enabling timely uplink data transmission for low latency services while maintaining accurate ONU registration.
Implementation Method 1
The OLT estimates, according to the first distance, a time at which a first uplink signal, which is sent on the first uplink bandwidth in a first sending mode by the ONU to be registered in response to the first message, arrives at the OLT
Data Source
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AI summary
A ranging method for an optical network, an OLT, an ONU, and an optical network system are provided. The OLT sends a bandwidth allocation message to the ONU; an OLT receiving a response message sent by an ONU in a first sending mode, wherein the first sending mode comprises sending power and a transmission rate; and the OLT performs ranging on the ONU according to the response message.