LDPC Check Matrix Switching for Flexible Code Rates

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Solution Overview

Problem

The method for improving error correction capability by changing the code rate of LDPC codes using puncturing techniques leads to increased power consumption and a deterioration in error correction capability, as it requires processing overhead and reduces the number of iterative decoding iterations.

Innovation Solution

A transmitter system that employs a check matrix with cyclic permutation matrices, allowing for efficient switching between different code rates by rearranging connection relationships between variable and check nodes, using a common check matrix for both high and low code rates to maintain error correction capability while reducing circuit size and power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If puncturing techniques are used to change code rate of LDPC codes, then code rate flexibility is improved, but power consumption increases and error correction capability deteriorates

Engineering Contradiction:
Improvecode rate flexibilityVSAvoidpower consumption
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The check matrix is divided into multiple submatrices, each corresponding to a specific code rate. By selecting and connecting appropriate submatrices, the system achieves code rate flexibility without requiring puncturing operations, thereby reducing power consumption while maintaining error correction capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connection relationships between variable nodes and check nodes are made dynamically configurable based on the desired code rate. Switching mechanisms allow the system to adaptively reconfigure the decoding graph structure, enabling flexible code rate changes without the energy overhead and performance degradation associated with puncturing techniques.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If puncturing techniques are used to change code rate of LDPC codes, then code rate flexibility is improved, but error correction capability deteriorates

Engineering Contradiction:
Improvecode rate flexibilityVSAvoiderror correction capability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The check matrix is segmented into multiple submatrices, each optimized for specific code rates. This segmentation allows the system to maintain dedicated, optimized decoding structures for each code rate, preserving error correction capability while achieving flexibility through selective submatrix connection rather than puncturing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system changes the structural parameters of the decoding graph by reconfiguring connection relationships between variable nodes and check nodes based on the target code rate. This parameter change approach maintains optimal error correction performance for each code rate while providing the desired flexibility, avoiding the performance degradation caused by puncturing.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If multiple check matrices are used for different code rates, then error correction capability is maintained, but device complexity increases

Engineering Contradiction:
Improveerror correction capabilityVSAvoidcircuit size
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple check matrices for different code rates are merged into a single unified check matrix structure with configurable submatrices. This merging approach allows the system to maintain error correction capability for multiple code rates while reducing device complexity by sharing common hardware resources and avoiding the need for separate dedicated matrices for each code rate.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The unified check matrix structure serves multiple functions by supporting different code rates through configurable submatrix connections. This multi-functionality reduces device complexity by eliminating the need for separate check matrices for each code rate, while maintaining optimized error correction capability across all supported code rates through appropriate submatrix selection and connection.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3771105B1Transmitter, receiver, communication system, and coding rate revision method
Publication Date: 2022.10.05 MITSUBISHI ELECTRIC CORP
  • EP3771105B1 patent drawingFigure 1
  • EP3771105B1 patent drawingFigure 2
  • EP3771105B1 patent drawingFigure 3~4

AI summary

A transmitter (10) according to the present invention includes: an encoding unit (11) that generates a code word by performing coding with a low-density parity-check code using a check matrix, the encoding unit (11) being capable of switching the check matrix for use in generating the code word, between a first check matrix with a first code rate and a second check matrix with a second code rate smaller than the first code rate, the first check matrix containing a plurality of cyclic permutation matrices, the encoding unit (11) generating the second check matrix by masking the cyclic permutation matrix at a predetermined position in the first check matrix and adding a row with a column weight equal to or less than a threshold; and a transmission unit (12) that transmits the code word.