LDPC Lifting Factor Selection for Flexible Wireless Code Blocks
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Solution Overview
Problem
Current LDPC code systems face challenges in supporting flexible code lengths and code rates, particularly in wireless communication systems, where existing methods struggle to efficiently encode and decode information bit sequences with varying lengths effectively.
Innovation Solution
The proposed solution involves using a low-density parity-check (LDPC) matrix obtained through a lifting factor Z and a base matrix, which includes specific row and column transformations, allowing for the encoding and decoding of input sequences with different lengths by determining the appropriate lifting factor based on the input sequence length, thereby supporting various code block lengths and rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed LDPC matrix is used for encoding, then the encoding structure is simple and hardware implementation is easier, but the system cannot support flexible code lengths and code rates
Solution Approach 1:
The patent applies dynamics by making the LDPC matrix configurable through a lifting factor Z that can be adjusted based on the input sequence length. The base matrix is expanded using different lifting factors to generate different-sized LDPC matrices, allowing the encoding structure to adapt dynamically to different code lengths and rates while maintaining a consistent base design.
Solution Approach 2:
The patent changes the parameter Z (lifting factor) to transform a fixed base matrix into multiple LDPC matrices with different dimensions. By varying Z, the system can support different code lengths and rates without changing the fundamental base matrix structure, thus achieving flexibility while controlling complexity.
2Adaptability or versatility
If different base matrices are used for different lifting factors, then various code block lengths can be supported, but the system complexity and overhead increase
Solution Approach 1:
The patent achieves universality by designing a single base matrix that can serve multiple functions through different lifting factors. The same base matrix structure is reused across different code block lengths by adjusting Z, eliminating the need for multiple distinct base matrices and reducing system complexity while maintaining versatility.
Solution Approach 2:
The system dynamically selects the appropriate lifting factor Z based on the required code block length, allowing a single base matrix to adapt to different coding requirements. This dynamic parameter adjustment reduces the need for multiple static matrix configurations.
3Reliability
If LDPC coding is used to improve reliability and power utilization, then error correction capability increases, but the decoding complexity and processing time increase
Solution Approach 1:
The patent segments the decoding process into parallel operations by exploiting the sparse structure of the LDPC matrix. The iterative decoding algorithm processes multiple check equations simultaneously, reducing the effective complexity per iteration while maintaining strong error correction capability through the distributed parallel computation.
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.