LDPC Base Matrix Lifting for Flexible Code Length and Rate
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Solution Overview
Problem
Current LDPC code systems face challenges in supporting diverse code block lengths and code rates, leading to limitations in encoding and decoding performance, particularly in wireless communication systems where flexibility is required.
Innovation Solution
The proposed solution involves using a lifting factor Z and a base matrix to generate LDPC matrices, allowing for different code block lengths by adjusting parameters such as row and column indices and shift values, enabling flexible code length and rate support through row/column transformations and storage of relevant parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed LDPC matrix structure is used, then decoding complexity is reduced, but adaptability to different code block lengths deteriorates
Solution Approach 1:
The patent implements dynamic selection of LDPC base matrices from a pre-defined set, where the selection is based on the actual code block length requirements. This allows the system to adapt its structure dynamically without increasing decoding complexity, as each base matrix is designed for specific length ranges.
Solution Approach 2:
The patent changes structural parameters of the LDPC matrix (specifically the base matrix selection and lifting factor) according to code block length requirements. By pre-defining multiple base matrices with different structures and selecting appropriate ones based on length parameters, the system achieves adaptability while maintaining manageable complexity.
2Adaptability or versatility
If multiple LDPC base matrices are stored to support different code block lengths, then adaptability improves, but device complexity increases
Solution Approach 1:
The patent segments the LDPC base matrices into multiple pre-defined types, each optimized for specific code block length ranges. This segmentation allows the system to store only the necessary subset of base matrices for given application requirements, reducing overall storage needs while maintaining adaptability across different scenarios.
Solution Approach 2:
The patent performs preliminary organization and classification of LDPC base matrices during system initialization or manufacturing. By pre-categorizing base matrices according to their suitable code block length ranges and characteristics, the system enables fast selection without complex runtime analysis, reducing operational complexity.
3Reliability
If code block length is increased, then error correction capability improves, but decoding time increases
Solution Approach 1:
The patent dynamically adjusts the lifting factor and base matrix selection based on code block length to optimize decoding speed. For longer code blocks, the system selects base matrices with structures that enable more efficient parallel decoding operations, thereby reducing the time penalty associated with increased block lengths.
Solution Approach 2:
The patent applies different base matrix structures and lifting factors to different segments or portions of the code block based on local requirements. This allows optimization of decoding speed for specific portions while maintaining overall error correction capability, effectively balancing reliability and time consumption.
Data Source
AI summary
Embodiments of this application disclose provides a low density parity check (LDPC) channel encoding method for use in a wireless communications system. A communication device encodes 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. Embodiments of the application provide eight particular designs of the base matrix. The encoding method provided in the embodiments of the application 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.