Flexible LDPC Matrix Coding for Variable 5G Code Lengths
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Solution Overview
Problem
Existing LDPC coding schemes struggle to efficiently support encoding and decoding of information bit sequences of varying lengths and code rates, limiting their flexibility and performance in wireless communication systems.
Innovation Solution
The proposed method utilizes a low density parity check (LDPC) matrix based on a lifting factor Z and base matrices, combined with row and column permutations, to create flexible LDPC codes that can accommodate different code block lengths and rates, enhancing encoding and decoding efficiency.
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 and rates deteriorates
Solution Approach 1:
The LDPC matrix is segmented into a base matrix and multiple permutation matrices. The base matrix provides a fixed structure for low decoding complexity, while the permutation matrices enable adaptability to different code block lengths and rates by selectively applying permutations to different columns of the base matrix.
Solution Approach 2:
The patent introduces dynamic column permutation to the otherwise static base matrix structure. By applying different column permutations based on the required code block length and rate, the system achieves adaptability while maintaining the underlying fixed structure that ensures low decoding complexity.
2Reliability
If LDPC codes are designed for specific code block lengths, then decoding performance is optimized, but flexibility to support varying lengths deteriorates
Solution Approach 1:
A single base matrix is designed to serve multiple code block lengths and rates through column permutation. This universal base matrix can be configured to support various code lengths (e.g., 512, 1024, 2048 bits) and code rates by selectively permuting columns, eliminating the need for separate matrices for each configuration.
Solution Approach 2:
The patent changes the parameter of column permutation to adapt the base matrix for different code block lengths and rates. By varying the permutation configuration rather than changing the entire matrix structure, the system maintains optimized decoding performance across different configurations while achieving flexibility.
3Reliability
If multiple LDPC matrices are designed for different code rates, then encoding performance is improved, but device complexity and storage requirements increase
Solution Approach 1:
Instead of designing separate LDPC matrices for different code rates, the patent creates a universal base matrix that can generate codes for multiple rates through column permutation. This single matrix structure serves multiple functions, reducing device complexity and storage requirements while maintaining optimized encoding performance for various code rates.
Solution Approach 2:
The patent extracts the rate-adaptation functionality from the matrix structure itself and implements it through column permutation operations. By separating the base matrix (containing the optimized structure) from the permutation operations (providing rate adaptation), the system achieves multiple code rates without requiring multiple complete matrices.
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.