Cable Modem Echo Cancellation Training for Full Duplex Coaxial Networks

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Solution Overview

Problem

In full duplex coaxial networks, existing systems face challenges in efficiently performing echo cancellation training when there are changes in channel assignment, leading to potential interference and suboptimal receiver performance.

Innovation Solution

A method and system for cable modem echo cancellation training in full duplex coaxial networks, where a cable modem receives a resource block assignment message from a cable modem termination system, determines changes in channel assignments, and initiates echo cancellation training if necessary, using a look-up table or training matrix to ensure proper echo cancellation across mixed downstream and upstream channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If echo cancellation training is performed frequently to ensure accurate echo cancellation, then receiver performance is improved, but system complexity and processing overhead increase

Engineering Contradiction:

Improvereceiver performanceVSAvoidsystem complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system performs echo cancellation training in advance when channel assignments change, rather than continuously during operation. The CMTS identifies RBA changes and triggers EC training proactively, ensuring echo cancellation is ready before it is needed, thus improving receiver performance without requiring continuous complex processing

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from RBA message changes to determine when EC training is needed. The CMTS monitors resource block assignment changes and triggers EC training only when necessary, creating a feedback-driven approach that balances performance requirements with system complexity by avoiding unnecessary training operations

Inventive Principle:

Principle #23Feedback

2Device complexity

If echo cancellation training is delayed to reduce processing overhead, then system complexity is reduced, but adjacent leakage interference increases

Engineering Contradiction:

Improveprocessing overheadVSAvoidadjacent leakage interference

Core Design Contradiction:

Device complexityVSObject-generated harmful factors

Solution Approach 1:

EC training is performed in advance when the CMTS detects an RBA change, ensuring that echo cancellation parameters are updated before full-duplex operations resume. This preliminary action prevents adjacent leakage interference from occurring during the transition, while still limiting processing overhead to only when necessary

Inventive Principle:

Principle #10Preliminary action

3Reliability

If continuous echo cancellation training is performed to maintain optimal performance, then receiver performance is improved, but loss of time for other operations increases

Engineering Contradiction:

Improvereceiver performanceVSAvoidtime for other operations

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

Instead of continuous EC training, the system performs EC training periodically only when RBAs change. The CMTS monitors for RBA changes and triggers EC training at these discrete intervals, ensuring receiver performance is maintained when channel assignments change while freeing up time for other operations during stable periods

Inventive Principle:

Principle #19Periodic action

4Measurement precision

If echo cancellation training is performed on all channels regardless of assignment changes, then echo cancellation accuracy is improved, but productivity of channel reallocation decreases

Engineering Contradiction:

Improveecho cancellation accuracyVSAvoidchannel reallocation efficiency

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The system applies EC training selectively only to channels whose assignments have changed, rather than uniformly to all channels. The CMTS identifies specific channels with assignment changes and triggers EC training only for those channels, maintaining echo cancellation accuracy for affected channels while improving overall channel reallocation efficiency by avoiding unnecessary training on unchanged channels

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS10523271B2Cable modem echo cancellation training in full duplex coaxial networks

Publication Date: 2019.12.31 FUTUREWEI TECHNOLOGIES INC

AI summary

A method, system, and apparatus for calibration for cable modem (CM) echo cancellation (EC) training in full duplex (FDX) coaxial networks is provided. A CM receives a current resource block assignment message (RBA) from a cable modem termination system (CMTS), and determines if designated channels available for assignment as downstream (DS) channels or upstream (US) channels have changed assignment values from a previously received RBA, and if EC training has been performed on the designated channels for the current RBA. If the designated channels have changed assignment values and EC training has not been performed on the designated channels for the current RBA, the CM performs EC training on the designated channels for the current RBA.