QC-LDPC Codebook Selection for Flexible 5G NR Code Rates

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Solution Overview

Problem

The development of 5G NR wireless communications requires efficient QC-LDPC coding and decoding methods, but specific standards for QC-LDPC-based coding and decoding are not yet defined, limiting implementation in next-generation communications.

Innovation Solution

Proposed methods involve generating QC-LDPC codes with embedded codebooks, quasi-row orthogonal layers, kernel matrices, and shift-coefficient designs to optimize encoding and decoding processes, allowing for flexible code rate support and efficient data transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If QC-LDPC coding methods are developed for 5G NR wireless communications, then encoding and decoding efficiency is improved, but device complexity increases due to the need to generate and manage multiple codebooks and optimization parameters

Engineering Contradiction:
Improveencoding and decoding efficiencyVSAvoiddevice complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent pre-calculates and stores optimization parameters (lifting factors, shift coefficients, codebook configurations) in tables before actual communication operations. During encoding/decoding, the system simply retrieves these pre-optimized parameters based on the required code rate, avoiding real-time complex calculations and reducing device complexity while maintaining high efficiency

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system optimizes multiple parameters including lifting factors, shift coefficients, and codebook sizes to achieve the best encoding/decoding efficiency for different code rates. By systematically varying and optimizing these parameters, the patent achieves high productivity while managing complexity through structured parameter management

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If multiple codebooks are embedded in QC-LDPC codes to support varying communication protocols, then adaptability is improved, but device complexity increases due to larger memory requirements and more complex codebook selection

Engineering Contradiction:
ImproveadaptabilityVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent divides the coding system into multiple codebooks, each optimized for specific code rate ranges or communication scenarios. The decoder segments the codebook selection process by using pre-defined thresholds and conditions to quickly identify the appropriate codebook, reducing the complexity of managing multiple codebooks while maintaining high adaptability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The QC-LDPC coding framework is designed to universally support multiple communication protocols and code rates through a unified structure that accommodates different codebooks. The base matrix and lifting mechanism provide a universal foundation that can adapt to various protocols without requiring completely separate decoding systems

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

3Quantity of substance

If lifting factors are optimized to reduce the number of tables stored, then memory usage is reduced, but encoding precision may be compromised due to fewer available lifting factor options

Engineering Contradiction:
Improvememory usageVSAvoidencoding precision
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent uses shift coefficient tables that can be reused across different lifting factors. Instead of storing separate optimization parameters for every possible lifting factor, the system copies and adapts shift coefficient tables from reference lifting factors, significantly reducing memory usage while maintaining encoding precision through the copying of proven parameter sets

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The system selectively optimizes which parameters are stored in tables versus which are calculated or copied. By changing the representation and storage of parameters (storing only critical optimization values rather than complete parameter sets), the patent reduces memory requirements while preserving encoding precision for the most critical parameters

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3902142A1QC-LDPC coding methods and apparatus
Publication Date: 2021.10.27 HFI INNOVATION INC
  • EP3902142A1 patent drawingFigure 1
  • EP3902142A1 patent drawingFigure 2
  • EP3902142A1 patent drawingFigure 3(A)~3(B)

AI summary

Concepts and schemes pertaining to quasi-cyclic-low-density parity-check (QC-LDPC) coding are described. A processor of an apparatus may generate a QC-LDPC code having a plurality of codebooks embedded therein. The processor may select a codebook from the plurality of codebooks. The processor may also encode data using the selected codebook. Alternatively or additionally, the processor may generate the QC-LDPC code including at least one quasi-row orthogonal layer. Alternatively or additionally, the processor may generate the QC-LDPC code including a base matrix a portion of which forming a kernel matrix that corresponds to a code rate of at least a threshold value.