QC-LDPC Matrix Lifting for Variable Code Lengths and Rates
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Solution Overview
Problem
Current LDPC code systems face challenges in supporting diverse code block lengths and code rates, which limits their flexibility and performance in various communication systems.
Innovation Solution
The proposed solution involves using a lifting factor Z and a base matrix to generate LDPC matrices that can support different code block lengths, achieved through row and column permutations and offsetting, allowing for flexible code length and rate requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed LDPC matrix structure is used, then the decoding complexity is low, but the system cannot support diverse code block lengths and code rates
Solution Approach 1:
The LDPC matrix is segmented into multiple submatrices with different structures (e.g., identity submatrices, zero submatrices, and parity-check submatrices). This segmentation allows the system to support diverse code block lengths and code rates by selectively activating different submatrices, while maintaining relatively simple decoding complexity for each segment.
Solution Approach 2:
The patent employs dynamic LDPC matrix construction where the matrix structure adapts based on code block length and code rate requirements. Different matrix configurations are selected or generated dynamically to match transmission conditions, enabling versatile support for various parameters without permanently increasing system complexity.
2Reliability
If LDPC code is used to increase channel transmission reliability, then the error correction capability is improved, but the system complexity increases
Solution Approach 1:
The LDPC matrix is designed with local quality variations where different submatrices have different structures optimized for specific functions. Identity submatrices provide simple encoding, zero submatrices reduce complexity, and carefully designed parity-check submatrices provide error correction. This local differentiation improves reliability while controlling overall complexity.
Solution Approach 2:
The patent changes key parameters of the LDPC matrix (such as the size and structure of submatrices, the number of parity bits, and the distribution of non-zero elements) to optimize the balance between reliability and complexity. By adjusting these parameters, the system achieves high channel transmission reliability while maintaining manageable encoding and decoding complexity.
3Productivity
If QC-LDPC matrices with high parallelism are used, then the throughput is improved, but the hardware requirements increase
Solution Approach 1:
The patent merges multiple LDPC matrices with different structures into a unified matrix framework. This consolidation allows the system to achieve high throughput by processing multiple code blocks simultaneously using the same hardware resources, rather than requiring separate hardware for each matrix type, thereby improving productivity while controlling hardware quantity.
Data Source
AI summary
A low density parity check (LDPC) channel encoding method for use in a wireless communications system includes a communication device encoding an input bit sequence by using a LDPC matrix to obtain an encoded bit sequence for transmission. The LDPC matrix is obtained based on a lifting factor Z and a base matrix. The encoding method can be used in various communications systems including the fifth generation (5G) telecommunication systems, and can support various encoding requirements for information bit sequences with different code lengths.