FEXT Matrix Crosstalk Simulation for DSL Testing

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Solution Overview

Problem

Existing DSL systems lack effective methods to simulate and test dynamic crosstalk environments, particularly in multipair systems, leading to unreliable performance assessments due to variations in coupling paths and non-stationary noise conditions.

Innovation Solution

A system and method for simulating far end crosstalk using a FEXT matrix with loop simulators and scaling blocks, allowing for reproducible crosstalk environments by filtering and scaling input signals to create a manageable and realistic testing scenario.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a real cable plant with multiple cable segments is used to simulate crosstalk, then any-to-any pair crosstalk can be experienced, but the system becomes complex and results are not reproducible due to variations in coupling paths

Engineering Contradiction:

Improvecrosstalk simulation capabilityVSAvoidcable plant configuration

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent creates a simplified copy of the real cable plant environment by using a reduced number of line pairs (e.g., 2 victim lines and 2 disturber lines) that replicates the essential crosstalk characteristics. This copy approach allows reproducible testing while maintaining the ability to simulate any-to-any pair crosstalk conditions without requiring the full complexity of a complete cable plant with all possible pair combinations.

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent segments the crosstalk simulation into distinct functional components: victim lines for performance analysis, disturber lines for generating interference, and coupling paths for modeling interference transfer. This segmentation allows each component to be independently configured and tested, simplifying the overall system while maintaining simulation accuracy.

Inventive Principle:

Principle #1Segmentation

2Device complexity

If noise models are applied in a stationary fashion using a noise generator, then the implementation is simple, but dynamic behavior and robustness under non-stationary noise conditions cannot be tested

Engineering Contradiction:

Improvetesting system structureVSAvoiddynamic noise condition simulation

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic crosstalk simulation by allowing the coupling paths between disturber and victim lines to vary over time, enabling the system to model non-stationary noise conditions. This dynamic capability allows testing of DSL system robustness during startup and other transient conditions, moving beyond static noise models while maintaining manageable system complexity through the reduced line pair configuration.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS8270287B2Twisted pair cable plant cross talk coupling simulator

Publication Date: 2012.09.18 ALCATEL LUCENT SA

AI summary

Example embodiments are directed to a system for simulating far end crosstalk (FEXT). The system includes digital subscriber lines coupled to a FEET matrix which simulates the FEXT environment. The FEXT matrix simulates the FEXT environment using filters disposed in disturber lines. Signals output from the filters are added to a path in the victim line to create an output signal.