QC-LDPC Lifting and Base Matrix Selection for Variable Code Lengths
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Solution Overview
Problem
Existing LDPC code technologies face challenges in supporting various input lengths and code rates, particularly with the existing lifting method limiting the length of QC-LDPC codes and making it difficult to apply to communication systems requiring high length compatibility.
Innovation Solution
The proposed method involves using a lifting method that adjusts the exponent matrix values based on different L values, allowing for the generation of LDPC codes with various lengths and code rates by determining one of two base matrices based on the transport block size and code rate, enabling flexible encoding and decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a lifting method is used to generate QC-LDPC codes, then code length can be adjusted, but the code length is limited and length compatibility is poor
Solution Approach 1:
The patent divides the QC-LDPC code structure into base matrices of different sizes (e.g., 6×6, 8×8, 10×10, 12×12) that can be selectively used. Each base matrix can be independently configured to support specific code lengths, allowing the system to segment the code generation process into manageable blocks that can be adapted to different length requirements without requiring a complete redesign of the code structure.
Solution Approach 2:
The patent changes the parameter of base matrix size to achieve different code lengths and rates. By selecting different base matrix dimensions (6×6, 8×8, 10×10, 12×12) and configuring the exponent values within these matrices, the system can generate QC-LDPC codes with various lengths (e.g., 512, 1024, 1536, 2048 bits) and rates, thereby improving length compatibility while maintaining a systematic approach to code generation.
2Reliability
If LDPC codes are designed for specific code rates and lengths, then encoding performance is optimized, but adaptability to various input lengths and code rates is reduced
Solution Approach 1:
The patent creates a universal base matrix framework that can serve multiple functions. The same base matrix structure can be configured to support different code rates (e.g., 1/2, 2/3, 3/4, 5/6) and different code lengths by adjusting the exponent values and selecting different base matrix sizes. This multi-functional design allows the system to maintain optimized encoding performance across various configurations without requiring separate code designs for each rate and length combination.
Solution Approach 2:
The patent introduces dynamic configurability to the LDPC code design. The base matrices are designed with adjustable parameters that can be dynamically configured based on the required code rate and length. For example, the exponent values in the base matrices can be adjusted, and different base matrix sizes can be selected, allowing the system to adapt to different transmission conditions and requirements while maintaining optimal encoding performance for each specific configuration.
3Adaptability or versatility
If multiple base matrices are used to support various lengths, then length compatibility improves, but system complexity increases
Solution Approach 1:
The patent performs preliminary configuration of base matrices with predetermined structures and exponent values. The base matrices are pre-designed to support specific code rates and lengths, so when the system needs to generate a QC-LDPC code, it can simply select the appropriate pre-configured base matrix based on the required parameters. This preliminary preparation reduces the complexity of real-time configuration and selection, as the heavy design work has already been done in advance.
Solution Approach 2:
The patent applies different base matrix configurations to different parts of the code generation process based on local requirements. Each base matrix is optimized for specific code rates and lengths, allowing the system to select the most appropriate configuration for each particular transmission scenario. This localized optimization approach ensures that each part of the system uses the most suitable base matrix for its specific needs, improving overall efficiency without requiring a complete redesign for each scenario.
Data Source
AI summary
This disclosure relates to a 5G or pre-5G communication system for supporting a higher data transfer rate than a 4G communication system such as LTE. The present invention relates to a method for encoding and decoding a channel in a communication or broadcasting system, comprising the steps of: determining an input bit size (CBS); determining a code rate (R); determining a size (Z) of a block; comparing the determined CBS and code rate with predetermined reference values; determining an LDPC sequence to perform LDPC encoding according to the comparison result; and performing LDPC encoding and decoding on the basis of the LDPC sequence and the block size. Further, the present invention comprises the steps of: determining a code rate (R) indicated by a modulation and coding scheme (MCS) index; determining a transport block size; and determining either a first basic matrix or a second basic matrix as a basic matrix on the basis of the transport block size and the code rate.