Quasi-Cyclic LDPC Encoding for Flexible 5G Code Rates
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Solution Overview
Problem
Current LDPC encoding solutions are not suitable for the 5G system, particularly in the eMBB scenario, as they fail to provide adequate performance and flexibility in supporting various code rates and information bit lengths with low storage complexity.
Innovation Solution
The proposed solution involves designing a quasi-cyclic LDPC code with a check matrix constructed using circular permutation matrices and cyclic coefficient exponent matrices, which are optimized to support a range of code rates and information bit lengths, and incorporating incremental redundancy to enhance performance and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional LDPC encoding solutions are used, then the encoding can be implemented, but the encoding performance is insufficient and not suitable for 5G system requirements
Solution Approach 1:
The patent applies parameter changes by optimizing the base matrix structure with specific cyclic shift values (e.g., P=163, P=179, P=211) and configuring the check matrix to support multiple code rates (1/5, 1/6, 1/8, 1/9, 2/3, 3/4, 4/5, 5/6). These parameter optimizations enable the LDPC code to achieve superior encoding performance while meeting diverse 5G system requirements for different transmission scenarios.
2Reliability
If the check matrix density is reduced to satisfy sparsity requirements, then decoding feasibility is improved, but the code length increases
Solution Approach 1:
The patent applies local quality by constructing the check matrix with non-uniform cyclic shift values for different sub-matrices. For example, different P values (163, 179, 211) are used in different positions of the base matrix, creating local variations in the check matrix structure. This allows the matrix to maintain overall sparsity for decoding feasibility while optimizing local regions to support shorter effective code lengths through incremental redundancy.
3Adaptability or versatility
If the LDPC code is designed to support various code rates and information bit lengths, then adaptability is improved, but storage complexity increases
Solution Approach 1:
The patent applies universality by designing a single base matrix structure that can generate multiple check matrices for different code rates and information bit lengths. The base matrix with configurable cyclic shifts serves as a universal template that can be adapted to support code rates ranging from 1/5 to 5/6 and various information bit lengths, eliminating the need to store separate pre-generated check matrices for each configuration and thus reducing storage complexity.
Data Source
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AI summary
An encoding method and apparatus, and a computer storage medium, wherein same are used to improve the LDPC encoding performance, and are thus suitable for 5G systems. The encoding method comprises: determining a base graph of a low density parity check code (LDPC) matrix, and constructing a cyclic coefficient index matrix; determining a sub-cyclic matrix according to the cyclic coefficient index matrix; and carrying out LDPC encoding according to the sub-cyclic matrix and the base graph.