Modulation Analysis Using Pre-Equalization Coefficients

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Solution Overview

Problem

Current methods for characterizing upstream communication channels are expensive, require specialized skills, and cause user downtime, while also being limited in capacity and unable to efficiently identify and resolve signal impairments in real-time streaming protocols.

Innovation Solution

The use of pre-equalization coefficients in conjunction with Fourier analysis to derive an inverse channel response and synthesize QAM symbols, allowing for the identification of radial tilt and voltage dispersion caused by distortion sources, and determining the presence of non-linear distortion sources in the network.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional packages are used to characterize upstream communication channels, then measurement precision is improved, but device complexity and cost increase significantly

Engineering Contradiction:

Improvechannel characterization accuracyVSAvoidhardware complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent creates a virtual copy of the channel characterization functionality by synthesizing QAM symbols mathematically to replicate the effect of physical QAM analysis hardware. This allows the system to perform channel characterization through software-based symbol synthesis and analysis rather than requiring expensive physical measurement equipment.

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical/physical measurement system (QAM analysis hardware) with a computational/mathematical system. By using pre-equalization coefficients and Fourier analysis to synthesize QAM symbols, the system substitutes physical measurement apparatus with algorithmic processing to achieve the same channel characterization function.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If traditional packages are used to characterize upstream communication channels, then measurement precision is improved, but loss of time increases due to user downtime

Engineering Contradiction:

Improvechannel characterization accuracyVSAvoiduser downtime

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent enables the network system to perform self-diagnosis and self-characterization by analyzing pre-equalization coefficients already available from normal modem operations. The system uses existing operational data and pre-equalization information to characterize channels without requiring separate measurement campaigns that would interrupt user service.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent utilizes pre-equalization coefficients that are calculated in advance during normal modem operation to perform channel characterization. By preparing and storing these coefficients beforehand, the system can conduct analysis without requiring real-time hardware intervention that would cause user downtime.

Inventive Principle:

Principle #10Preliminary action

3Measurement precision

If traditional packages are used to characterize upstream communication channels, then measurement precision is improved, but productivity decreases due to limited capacity

Engineering Contradiction:

Improvechannel characterization accuracyVSAvoidanalysis throughput

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent creates a universal analysis system that can characterize multiple upstream communication channels simultaneously using the same software-based approach. By replacing hardware limitations with computational scalability, the system can process multiple channels in parallel without being constrained by physical device capacity, thereby improving overall productivity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 enables efficient and accurate characterization of upstream communication channels, reducing user downtime and identifying the probable location of non-linear distortion sources, thereby improving network performance without the need for expensive hardware or specialized skills.

Implementation Method 1

pre-equalization coefficients may be used in conjunction with Fourier analysis to derive an inverse channel response of a return path spectrum

Methodology Applied

Scientific EffectFourier analysis:

Data Source

PatentUS10187397B2Modulation analysis and distortion identification

Publication Date: 2019.01.22 COMCAST CABLE COMM LLC

AI summary

An apparatus, method, computer readable medium, and system are provided to determine whether a non-linear signal impairment is present in a network communication channel. For instance, a computing device may transmit equalization coefficients to a user device to modify future signals generated by the user device. If the equalization coefficients are unable to reduce a signal impairment, the signal impairment may be a non-linear signal impairment. The computing device may generate symbol placements based on signals received from the user device and transmit status messages.