LDPC Basis Matrix Shift-Factor Tuning for Low Error Floors
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Solution Overview
Problem
Generating low-density parity-check code basis matrices with varying lifting factors often results in poor cycle length properties, leading to high error floors in parity check matrices, affecting data transmission reliability.
Innovation Solution
A method to generate low-density parity-check code basis matrices by iteratively selecting and replacing matrix elements with shift factors, improving cycle length properties, ensuring that parity check matrices expanded using different lifting factors have good average cycle length properties and low error floors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a same basis matrix is expanded using multiple different lifting factors, then the wireless communications device can support QC-LDPCs of different code lengths, but the cycle length property of the obtained parity check matrices becomes poor
Solution Approach 1:
The patent applies local quality by making different parts of the basis matrix have different properties. Specifically, different sub-matrices within the basis matrix are designed with different lifting factors and shift values, allowing each sub-matrix to contribute differently to the overall cycle length property. This enables the system to maintain good cycle length properties across multiple expanded matrices while supporting different code lengths.
Solution Approach 2:
The patent changes parameters (lifting factors and shift values) of the basis matrix to resolve the contradiction. By carefully selecting different lifting factors for different sub-matrices and optimizing shift values, the patent ensures that expanded matrices with different code lengths all achieve good cycle length properties, thereby improving reliability while maintaining adaptability.
2Adaptability or versatility
If a basis matrix is expanded with lifting factors to support different code lengths, then versatility is improved, but the error floor increases due to poor cycle length property
Solution Approach 1:
The patent divides the basis matrix into sub-matrices with different local properties. Each sub-matrix is designed with specific lifting factors and shift values that optimize the cycle length property for that local region. This local optimization prevents the formation of short cycles that would otherwise create high error floors, while still allowing the overall system to support multiple code lengths.
Solution Approach 2:
The patent performs preliminary design and optimization of the basis matrix structure before expansion. By pre-configuring the lifting factors and shift values in the basis matrix, the patent ensures that when expansion occurs for different code lengths, the resulting parity check matrices inherently possess good cycle length properties and low error floors, rather than requiring post-processing corrections.
Data Source
AI summary
The present disclosure relates to methods and apparatuses for generating a low-density parity-check code basis matrix. One example method includes obtaining a low-density parity-check code mother matrix, and generating a 1st matrix to a qth matrix one by one, where q is a preset positive integer. A Pth matrix in the 1st matrix to the qth matrix is generated in the following manner: selecting a to-be-replaced matrix element in a (P−1)th matrix, where the to-be-replaced matrix element is a matrix element having a value that is not −1 in the (P−1)th matrix, determining a Pth shift factor corresponding to the to-be-replaced matrix element, and replacing the to-be-replaced matrix element in the (P−1)th matrix with the Pth shift factor to obtain the Pth matrix whose cycle length property is better than a cycle length property of the (P−1)th matrix.