Quasi-Cyclic LDPC Matrix Selection for Flexible Code Rates
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Solution Overview
Problem
Existing LDPC coding and decoding processes lack flexibility in terms of code rate and code length, which limits their adaptability to various communication standards and scenarios.
Innovation Solution
A quasi-cyclic LDPC coding and decoding method and apparatus that determines a basic matrix from a mother basic matrix set, using first-type and second-type elements, to support flexible code lengths and rates, thereby enhancing the flexibility of the LDPC coding and decoding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional LDPC coding is used with fixed code rates and lengths, then the coding and decoding process is simple, but the adaptability to various communication standards and scenarios is limited
Solution Approach 1:
The patent implements dynamic selection of code rates and code lengths by introducing a code rate determination module that selects from multiple pre-defined code rates based on communication requirements. The basic matrix is designed to support variable code lengths through flexible column selection, enabling the system to adapt to different transmission scenarios without requiring multiple separate coding schemes.
Solution Approach 2:
The patent creates a universal LDPC coding framework that can handle multiple code rates (1/2, 2/3, 3/4, 4/5, 5/6) and various code lengths within a single system. The basic matrix structure serves multiple functions: it supports different code rates through column selection, accommodates various code lengths, and maintains compatibility with existing LDPC decoding algorithms, thereby eliminating the need for separate coding schemes for different scenarios.
2Adaptability or versatility
If flexible code rates and lengths are supported, then adaptability to communication standards improves, but the complexity of the coding and decoding process increases
Solution Approach 1:
The patent segments the LDPC code structure into a basic matrix and its expansions. The basic matrix contains fundamental patterns that can be systematically expanded to generate codes with different rates and lengths. This segmentation allows the system to maintain a compact core structure while providing flexible expansion capabilities, reducing the overall complexity compared to designing entirely separate codes for each rate and length combination.
Solution Approach 2:
The patent enables parameter changes by allowing dynamic selection of code rate and code length parameters without changing the fundamental coding structure. The system maintains the same basic matrix and decoding algorithm while varying operational parameters (code rate, code length) to match different communication requirements, thereby achieving flexibility without proportional increases in complexity.
Data Source
AI summary
A quasi-cyclic LDPC coding and decoding method and apparatus, and an LDPC coder and decoder. The method includes: determining from a mother basis matrix set a basis matrix used for low density parity check (LDPC) coding (S202), wherein the basis matrix used for LDPC coding includes a first-type element and a second-type element, the first-type element corresponds to an all-zero square matrix, the second-type element corresponds to a matrix obtained by means of a cyclic shift of a unit matrix according to a value of the second-type element, and dimensions of the all-zero square matrix and the unit matrix are equal; and performing LDPC coding on an information sequence to be coded according to the basis matrix used for LDPC coding, and/or performing LDPC decoding on a data sequence to be decoded according to the basis matrix used for LDPC coding (S204).