Crosstalk Testing via Orthogonal Spread Spectrum Codes

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Solution Overview

Problem

Current technologies for addressing crosstalk in multi-subscriber communication lines are complex and primarily optimize DSL line performance based on statistical characteristics, failing to provide quantitative crosstalk tests, which limits the ability to significantly enhance transmission performance and activation rates of DSLAM systems.

Innovation Solution

A method involving the loading of orthogonal spread spectrum codes onto communication lines, using Fast Fourier Transform to obtain crosstalk vector information, and calculating quantitative crosstalk values through despreading and modulo operations, allowing for real-time crosstalk testing and identification without impacting transmission performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If current multi-subscriber detection technologies are used to address crosstalk, then system performance is optimized based on statistical characteristics, but the complexity of the technology increases and quantitative crosstalk testing cannot be provided

Engineering Contradiction:
Improvesystem performanceVSAvoidtechnology complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex statistical signal processing methods with a simpler electrical measurement approach. By injecting test signals and directly measuring voltage differences at the DSLAM end, the system obtains quantitative crosstalk values without requiring complex multi-subscriber detection algorithms or statistical characteristic analysis.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediary test signal injection mechanism. A test signal is injected into the DSL line, and the resulting voltage response is measured. This intermediary measurement approach allows quantitative crosstalk assessment without directly implementing complex detection technologies on the communication signals themselves.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If current technologies optimize DSL line performance based on statistical characteristics, then some performance improvement is achieved, but transmission performance cannot be optimized significantly due to lack of quantitative crosstalk testing

Engineering Contradiction:
ImproveDSL line performanceVSAvoidcrosstalk measurement capability
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent replaces indirect statistical inference methods with direct electrical measurement. By measuring the actual voltage difference caused by crosstalk signals at the DSLAM terminal, the system achieves precise quantitative crosstalk values that can directly guide performance optimization decisions.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the measurement parameter from statistical characteristics of communication signals to direct voltage response to test signals. This parameter change enables precise quantitative measurement of crosstalk levels, providing actionable data for optimizing DSL line performance and activation rates.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP1940140B1Method, apparatus and system for crosstalk testing of multi-user communication line
Publication Date: 2012.08.15 HUAWEI TECH CO LTD
  • EP1940140B1 patent drawingFigure 1~3
  • EP1940140B1 patent drawingFigure 4~5
  • EP1940140B1 patent drawingFigure 6~8

AI summary

A method, apparatus, and system for crosstalk test on multi-subscriber communication lines. The core of the invention is: loading a group of orthogonal spread spectrum codes to the transmitting side of each line, and testing the crosstalk of xSDL lines based on the received signal vector at the receiving side so that the source, amplitude, and phase of the crosstalk can be identified. With the invention, crosstalk test can be implemented in real time on xSDL lines without impacting the transmission performance of other lines. In addition, the test result shows how many lines have a significant impact on the line under test and reflects the severity of the impact, providing a powerful basis for dynamic spectrum management, and optimization of DSLAM system performance.