LDPC Parity-Check Matrix Selection for Variable Block Lengths

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Solution Overview

Problem

Broadcast and communication systems using LDPC codes face challenges in maintaining high data reception quality due to variable block lengths and coding rates, especially in mobile and semi-fixed environments, where existing methods struggle to optimize error correction performance effectively.

Innovation Solution

The system employs a method to select between two coding methods based on different parity check matrices, allowing for variable coding rates and block lengths by using puncturing to adjust the number of bits transmitted, and corresponding decoding methods are applied at the receiving end to ensure optimal error correction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single LDPC code configuration is used, then the system structure is simple, but error correction performance deteriorates in variable block length and coding rate scenarios

Engineering Contradiction:

Improveerror correction performanceVSAvoidsystem structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the LDPC code configuration into multiple code sets, each optimized for specific block lengths and coding rates. Instead of using a single universal LDPC code, the system segments the code space into multiple specialized code configurations that can be selected based on transmission requirements, thereby improving error correction performance for variable conditions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic selection of LDPC code configurations based on the required block length and coding rate. The system can adaptively choose the appropriate code set and code index from multiple available configurations, enabling flexible adaptation to varying transmission conditions while maintaining optimal error correction performance.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If multiple LDPC code configurations are used to handle variable block lengths and coding rates, then error correction performance improves, but the complexity of code selection and management increases

Engineering Contradiction:

Improvevariable block length and coding rate supportVSAvoidcode selection and management

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent creates a universal LDPC code management system that can handle multiple code configurations through a unified interface. The transmitting and receiving devices both support multiple code sets and can selectively apply appropriate codes based on control information, providing multi-functional capability while maintaining systematic management through standardized procedures.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent manages the complexity of multiple LDPC code configurations by parameterizing the code selection process. Instead of hardcoding multiple independent code management systems, the invention uses parameter-based selection where code set index and code index are transmitted as control information, allowing flexible configuration management through parameter changes rather than structural complexity.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If puncturing is used to adjust coding rate, then coding rate flexibility improves, but decoding complexity increases

Engineering Contradiction:

Improvecoding rate flexibilityVSAvoiddecoding process

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent performs preliminary configuration of puncturing patterns during code design and transmission. The transmitting device determines the appropriate puncturing scheme in advance based on the desired coding rate, and the receiving device is pre-equipped with corresponding depuncturing capabilities. This preliminary preparation reduces the computational burden during actual decoding operations.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces control information as an intermediary that carries puncturing pattern information between transmitting and receiving devices. Instead of directly implementing complex puncturing and depuncturing operations, the system uses control information to convey the necessary parameters, allowing both devices to coordinate their puncturing/depuncturing operations through this intermediary communication channel.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11502782B2Transmitting device for performing an encoding process on an information bit sequence using a coding scheme selected from a coding scheme set

Publication Date: 2022.11.15 PANASONIC INTELLECTUAL PROPERTY CORP OF AMERICA

AI summary

One coding method of a plurality of coding methods including at least a first coding method and a second coding method is selected, an information sequence is encoded by using the selected coding method, and an encoded sequence obtained by performing predetermined processing on the information sequence is modulated and transmitted. The first coding method is a coding method having a first coding rate, for generating a first encoded sequence by performing puncturing processing on a generated first codeword by using a first parity check matrix. The second coding method is a coding method having a second coding rate, for generating a second encoded sequence by performing puncturing processing on a generated second codeword by using a second parity check matrix that is different from the first parity check matrix, the second coding rate after the puncturing process being different from the first coding rate.