Variable-Length LDPC Matrix Construction to Avoid Small Cycles
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Solution Overview
Problem
Current quasi-cyclic LDPC codes can only support code length increases by integral multiples, leading to performance variations across different code lengths, which is not optimal.
Innovation Solution
A method and device for encoding or decoding LDPC codes with variable lengths by grouping code lengths and using extension factors to construct a base exponential matrix, ensuring no small cycles occur, thereby supporting continuous changes in code lengths and improving performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If quasi-cyclic LDPC code uses fixed base matrix with extension factors, then code length can be scaled by integral multiples, but performance varies significantly across different code lengths
Solution Approach 1:
The patent applies dynamics by making the base matrix construction adaptive rather than fixed. The base matrix is dynamically constructed based on the target code length, using a systematic approach that selects appropriate extension factors and base matrix dimensions to match the required code length, thereby maintaining optimal performance across variable lengths.
Solution Approach 2:
The patent changes parameters by adjusting the base matrix dimensions and extension factors based on the target code length. Instead of using a single fixed base matrix, the system varies the base matrix parameters (rows, columns, and extension factors) to match different code length requirements, ensuring consistent performance across different scales.
2Device complexity
If quasi-cyclic LDPC code uses single base matrix for multiple code lengths, then storage is simplified, but performance at each code length is suboptimal
Solution Approach 1:
The patent applies local quality by optimizing the base matrix specifically for each target code length rather than using a one-size-fits-all approach. Each code length receives a locally optimized base matrix constructed with appropriate dimensions and extension factors, ensuring that each specific application gets the most suitable configuration for its requirements.
3Ease of manufacture
If LDPC code supports only integral multiple code lengths, then construction is simplified, but continuous code length changes are not supported
Solution Approach 1:
The patent makes the code construction dynamic by allowing the base matrix dimensions and extension factors to be selected based on the target code length. This dynamic approach enables continuous code length support while maintaining construction simplicity through a systematic selection process that adapts to different length requirements.
Solution Approach 2:
The patent segments the code length support into different ranges, each with its own optimized base matrix construction parameters. By dividing the code length space into segments and providing optimized constructions for each segment, the system achieves both simplicity within segments and flexibility across the full range of code lengths.
Data Source
AI summary
A method for encoding or decoding an LDPC code with variable code lengths is provided in an embodiment of the present invention. The method includes: obtaining a base exponential matrix of an LDPC code and grouping code lengths during construction of the base exponential matrix; correcting the base exponential matrix according to a grouping correction factor to obtain an exponential matrix of the group corresponding to the grouping correction factor; extending the exponential matrix by using an extension factor of a code length in the group to obtain an LDPC matrix corresponding to the code length; and implementing encoding or decoding by using the LDPC matrix. The method for encoding or decoding an LDPC code with variable code lengths provided in an embodiment of the present invention can be used to ensure that no small cycles occur at each required code length of the LDPC code obtained through multiple constructions. Thus, the performance can be greatly improved. In addition, a device for encoding or decoding, an encoder, and a decoder are provided in embodiments of the present invention.