LDPC Base Matrix Generation for Fixed Puncturing Patterns

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Solution Overview

Problem

In wireless communications networks with limited frequency resources, the reliability and effectiveness of information transmission are compromised due to high computational complexity and slow convergence in decoding LDPC codes, especially when using incremental redundancy HARQ, where poor puncturing patterns lead to increased decoding errors.

Innovation Solution

A method for generating a base matrix of LDPC codes with a fixed puncturing pattern is introduced, involving transformations of an initial matrix to determine a check bit part and information bit part, ensuring performance by transforming the base matrix based on a predetermined pattern, thereby reducing decoding errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If row combination and column deletion are performed on the initial check matrix based on a poor puncturing pattern, then the transformed check matrix can be obtained, but the performance of the transformed check matrix deteriorates and the probability of decoding error increases

Engineering Contradiction:
Improvedecoding performanceVSAvoidtransformation operation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent pre-generates multiple transformed check matrices corresponding to different puncturing patterns before actual decoding. When a punctured codeword is received, the system directly selects the pre-generated transformed check matrix that matches the puncturing pattern, avoiding real-time transformation operations. This preliminary preparation ensures that even with poor puncturing patterns, the correct transformed matrix is available, maintaining decoding performance without computational overhead.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the parameter of the check matrix by pre-computing transformed versions with different column deletion patterns. Instead of performing dynamic transformation based on the received puncturing pattern, the system prepares multiple static transformed matrices in advance with varying structures. This parameter variation allows the receiver to select the appropriate pre-transformed matrix, ensuring optimal decoding performance regardless of the puncturing pattern quality.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the receive end performs transformation operations on the initial check matrix to obtain a transformed check matrix, then the decoding can be performed with the correct bit rate, but the computational complexity increases and convergence speed decreases

Engineering Contradiction:
Improvedecoding speedVSAvoidtransformation operation complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent performs the computationally intensive transformation operations in advance during system initialization or code generation phase. Multiple transformed check matrices are pre-computed and stored. During actual decoding operations, the receiver simply retrieves the appropriate pre-transformed matrix without performing any transformation operations, thereby eliminating the computational complexity and convergence delay that would otherwise occur during real-time decoding.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates multiple copies of the check matrix, each transformed according to different puncturing patterns. Instead of copying and transforming the matrix dynamically during decoding, the system prepares multiple static copies in advance. This allows the receiver to directly use a pre-copied and pre-transformed matrix that matches the received codeword's puncturing pattern, avoiding real-time computational overhead.

Inventive Principle:
Principle #26Copying

3Reliability

If a fixed puncturing pattern is used in the base matrix generation, then the performance of the transformation matrix is ensured and decoding errors are reduced, but the adaptability to different channel environments decreases

Engineering Contradiction:
Improvedecoding accuracyVSAvoidchannel adaptation capability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal base matrix that can serve multiple functions by incorporating a fixed puncturing pattern structure. This base matrix is designed to work correctly with the fixed pattern while also enabling the generation of multiple transformed matrices through systematic column deletions. The fixed pattern provides a reliable foundation that ensures decoding accuracy, while the ability to generate multiple transformed versions maintains adaptability to different channel conditions and code rates.

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

Solution Approach 2:

The patent maintains a fixed puncturing pattern structure in the base matrix but allows parameter changes in the transformed matrices by deleting different numbers and positions of columns. The fixed pattern ensures structural integrity and decoding reliability, while variable parameter adjustments in the transformed matrices (different column deletions) provide adaptability to different channel environments and transmission requirements.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3477865B1Basis matrix generating method, coding/decoding method and apparatus for LDPC codes
Publication Date: 2021.07.28 HUAWEI TECH CO LTD
  • EP3477865B1 patent drawingFigure 1~2
  • EP3477865B1 patent drawingFigure 3
  • EP3477865B1 patent drawingFigure 4

AI summary

The present invention relates to a communications field, and discloses a method for generating a base matrix of an LDPC code, an encoding/decoding method, and a device, to resolve a problem that a probability of a decoding error increases because performance of a transformed check matrix cannot be ensured due to a poor puncturing pattern. A specific solution is as follows: A size of a check bit part of a base matrix is determined based on a required minimum bit rate, and the check bit part of the base matrix is determined based on the size of the check bit part and an initial matrix. The initial matrix is a matrix with a size of m×m that has a bidiagonal structure, the check bit part is a k-order transformation matrix Hk obtained after the initial matrix is transformed k times, k meets 2k-1m<T≤2km, and T is the size of the check bit part. An information bit part of the base matrix is determined based on the check bit part, and the base matrix is obtained based on the check bit part and the information bit part. The present invention is used in an encoding/decoding process.