PON Equalization Using Distance-Based OLT-ONU Parameter Classes

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Solution Overview

Problem

The implementation of equalization in passive optical networks (PON) is complex due to unknown transmission chain characteristics and varying OLT/ONU distances, making it difficult to achieve effective signal compensation across a wide range of distances, especially with high bitrates like 50 Gb/s NRZ.

Innovation Solution

Adapt equalization parameters based on specific OLT/ONU distances and other transmission parameters for each network ODN, rather than a general range, using methods like pre- and post-compensation to optimize signal transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If equalization is implemented using a general distance range approach, then it can cover all possible OLT/ONU distances, but the complexity of determining equalization parameters increases and effectiveness decreases

Engineering Contradiction:

Improvecoverage of OLT/ONU distance rangeVSAvoidcomplexity of equalization parameter determination

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the continuous distance range into discrete distance classes (e.g., 0-5km, 5-10km, 10-20km). Each distance class has its own predetermined equalization parameters. This segmentation allows the system to cover all distances while simplifying parameter determination, as the OLT only needs to identify which class the ONU falls into and apply the corresponding parameters.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent pre-calculates and stores equalization parameters for each distance class before actual operation. During runtime, the OLT only needs to determine the distance class and retrieve the pre-computed parameters, avoiding complex real-time calculations. This preliminary action significantly reduces the complexity of parameter determination during actual equalization operations.

Inventive Principle:

Principle #10Preliminary action

2Manufacturing precision

If equalization parameters are determined for each specific OLT/ONU distance, then equalization accuracy improves, but the complexity of the system increases

Engineering Contradiction:

Improveequalization accuracyVSAvoidsystem complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by assigning specific equalization parameters tailored to each distance class. Instead of using a single general parameter set, the system optimizes parameters locally for each distance range, improving equalization accuracy for specific scenarios while maintaining manageable system complexity through the use of discrete classes rather than continuous parameters.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes equalization parameters based on the determined distance class. The OLT adjusts parameters such as equalization coefficients and filtering characteristics according to the ONU's distance category. This parameter adaptation improves accuracy for each specific distance scenario while avoiding the complexity of continuously varying parameters.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If bandwidth of emitter and receiver is increased to reduce distortion, then signal quality improves, but the cost and complexity of equipment increases

Engineering Contradiction:

Improvesignal qualityVSAvoidequipment complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces physical hardware improvements (increasing emitter and receiver bandwidth) with signal processing methods (equalization). Instead of requiring higher-bandwidth, more expensive components, the system uses digital signal processing to compensate for bandwidth limitations. This substitution maintains signal quality while avoiding the increased cost and complexity associated with higher-bandwidth hardware.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS12580653B2Method for equalization in an access network of passive optical network type, computer program product, optical line termination and optical network unit corresponding thereto

Publication Date: 2026.03.17 ORANGE SA

AI summary

A method for equalization in an access network of passive optical network type. The method includes, for a given optical distribution network connecting a given input port of an optical line termination to a given plurality of optical network units: for at least one of the optical network units of the given plurality, obtaining a distance between the optical line termination and the optical network unit; determining a representative distance associated with the given optical distribution network, according to the one or more distances obtained; determining at least one equalization parameter, according to the representative distance; and equalizing transmission channels within the given optical distribution network, according to the at least one equalization parameter, each of the transmission channels connecting the given port of the optical line termination to one of the optical network units of the given plurality.