Vectoring Coefficient Encoding with Differential Bit-Length Control

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Solution Overview

Problem

Current compression methods for vectoring coefficients in Vectoring Processors (VPs) are inefficient, leading to high memory requirements and increased costs due to the need for large on-chip memory to store and retrieve crosstalk cancellation data, especially in systems with diverse disturber properties and strong frequency correlations.

Innovation Solution

A novel compression scheme that differentially encodes vectoring coefficients using variable-length codes, adjusting the number of bits required for each coefficient based on previous values, to minimize overhead and optimize storage efficiency while maintaining fidelity, specifically designed for vectoring processors in access nodes providing broadband communication services.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If fixed-length encoding is used for vectoring coefficients, then decoding is simpler and faster, but memory requirements increase significantly

Engineering Contradiction:
Improvedecoding speedVSAvoidmemory requirements
Core Design Contradiction:
ProductivityVSQuantity of substance

Solution Approach 1:

The patent applies differential encoding where the number of bits allocated to encode each vectoring coefficient dynamically adapts based on the previous coefficient value. This creates a dynamic encoding scheme that exploits the statistical correlation between adjacent coefficients, allowing shorter codes for similar values and reducing overall memory requirements while maintaining efficient decoding through simple differential computation

Inventive Principle:
Principle #15Dynamics

2Quantity of substance

If variable-length encoding is used for vectoring coefficients, then memory requirements are reduced, but decoding complexity increases

Engineering Contradiction:
Improvememory requirementsVSAvoiddecoding complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent changes the encoding parameter from fixed bit-length to variable bit-length based on the magnitude of difference between consecutive coefficients. By encoding only the difference values and using adaptive bit allocation, the system reduces memory requirements while keeping decoding complexity manageable through a systematic approach to variable-length code generation and differential decoding

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If more bits are allocated per coefficient, then encoding precision is higher, but storage efficiency decreases

Engineering Contradiction:
Improvecoefficient encoding precisionVSAvoidstorage efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent applies local quality by allocating different numbers of bits to encode different coefficient values based on their local characteristics. Coefficients with small differences from previous values use fewer bits, while those with larger differences use more bits. This localized adaptive allocation maintains high precision where needed while improving overall storage efficiency by using minimal bits for redundant information

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3291452B1Encoding and decoding of vectoring coefficients with differential encoding size
Publication Date: 2020.03.25 ALCATEL LUCENT SA
  • EP3291452B1 patent drawingFigure 1
  • EP3291452B1 patent drawingFigure 2
  • EP3291452B1 patent drawingFigure 3

AI summary

The present invention relates to a method for encoding a first sequence of integer coefficient values ({x*(i ,j,2l-1)}=1, 2,...; {X*(i,j,21)}l=1,2,...) indicative of coupling coefficient values. In accordance with an embodiment of the invention, the method comprises determining a second sequence of numbers of digits for encoding the respective integer coefficient values of the first sequence, the second sequence comprising, as first element, a first number of digits for encoding the first integer coefficient value of the first sequence, and as second and subsequent elements, constrained numbers of digits that are greater than or equal to respective minimum required numbers of digits for encoding the second and subsequent integer coefficient values of the first sequence. The constrained numbers of digits are such that any two successive elements of the second sequence do not differ from each other by more than a given threshold value. The method further comprises encoding difference values between the successive elements of the second sequence; and encoding the integer coefficient values of the first sequence using the respective numbers of digits of the second sequence. The present invention also relates to a corresponding encoder, to a method for decoding, and to a corresponding decoder.