DSL Line Testing via SNR Margin and Moisture Monitoring

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Solution Overview

Problem

Existing methods for troubleshooting digital subscriber line (DSL) faults, particularly intermittent and weather-related issues, are inadequate as they often fail to detect faults when they occur, leading to service disruptions and inefficiencies in regular overnight line testing.

Innovation Solution

A method that continuously monitors signal-to-noise ratio (SNR) margin on DSL lines, using SNR measurements and atmospheric moisture sensors to trigger electrical line tests only when specific conditions are met, thereby identifying and addressing faults associated with wet joints and other intermittent issues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If regular overnight line testing is performed, then faults can be detected, but service disruptions occur and resources are wasted on testing when lines are not exhibiting problems

Engineering Contradiction:
Improvefault detection capabilityVSAvoidservice disruption time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary monitoring of SNR margin continuously during normal operation to detect degradation trends before faults occur. This allows the system to prepare for potential faults and trigger tests only when necessary, avoiding unnecessary overnight testing and service disruptions.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The testing strategy transitions from static regular overnight testing to dynamic condition-based testing. The system continuously monitors SNR margin and adapts testing frequency based on real-time line conditions, performing tests only when degradation patterns indicate imminent faults.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If continuous monitoring is performed, then fault detection precision is improved, but system complexity increases

Engineering Contradiction:
Improvefault detection precisionVSAvoidmonitoring system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system uses feedback from continuous SNR margin monitoring to dynamically control when electrical line tests are triggered. The monitoring provides continuous feedback on line health, and this feedback loops back to the test triggering mechanism, creating a closed-loop system that improves detection precision without requiring complex continuous testing infrastructure.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

SNR margin measurements serve as an intermediary parameter that indirectly indicates line health and fault conditions. Rather than directly monitoring complex fault conditions, the system uses SNR margin as a measurable intermediary that correlates with line degradation, simplifying the monitoring approach while maintaining high detection precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If electrical line tests are triggered on-demand, then testing resources are optimized, but intermittent faults may be missed

Engineering Contradiction:
Improvetesting efficiencyVSAvoidintermittent fault detection
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system performs preliminary continuous monitoring of SNR margin to identify degradation patterns before intermittent faults manifest. By detecting trends in SNR margin deterioration, the system can trigger electrical line tests at optimal moments when intermittent faults are most likely to be detected, rather than relying on random or scheduled testing.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system maintains continuous useful action through ongoing SNR margin monitoring during normal operation. This continuous monitoring ensures that the system is always aware of line conditions and can immediately trigger electrical line tests when degradation patterns indicate intermittent faults may be present, eliminating gaps in detection coverage.

Inventive Principle:
Principle #20Continuity of useful action

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 effectively reduces service outages by proactively identifying and testing DSL faults, especially those related to weather, without the need for frequent overnight testing, thereby improving fault detection and maintenance efficiency.

Implementation Method 1

continuously measures the signal to noise (SNR) margin on the DSL line

Methodology Applied
Scientific EffectSignal-to-noise ratio measurement:

Data Source

PatentEP3202129B1Optimised broadband line testing
Publication Date: 2018.06.27 BRITISH TELECOM PLC
  • EP3202129B1 patent drawingFigure 1
  • EP3202129B1 patent drawingFigure 2
  • EP3202129B1 patent drawingFigure 3

AI summary

This invention relates to a method of managing a digital subscriber line, where an optimum point at which to trigger a line test on the DSL line is determined. The invention continuously measures the signal to noise (SNR) margin on the DSL line, and compares the measurements to predetermined conditions based on SNR margin characteristics associated with a population of good lines. Once the SNR margin measurements fail to meet the predetermined conditions, an electrical line test is triggered. Thus, monitoring is done in the DSL domain, but the line test triggered is in the electrical domain. In an improved method, moisture level sensors provide a measure of the atmospheric moisture levels experienced by the line. If the SNR margin measurements fail to meet the predetermined conditions, and in addition there is a correlation with atmospheric moisture levels, then a line test is triggered on the line. This improvement picks up faults associated with wet joints that are generally intermittent in nature, and otherwise difficult to identify and properly test.