LDPC Base Graph Layout for Flexible Code Rates and Row-Parallel Decoding
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Solution Overview
Problem
Existing LDPC codes, particularly those used in new radio (NR) and 802.11ay, face limitations in decoding efficiency due to the inability to support parallel decoding of entire rows and flexible code rates, which restricts the implementation of incremental redundancy-hybrid automatic repeat request (IR-HARQ) mechanisms.
Innovation Solution
The proposed method involves obtaining an LDPC base graph based on a storage matrix and indication information, maintaining the total number of edges in the Tanner graph, and supporting flexible code rates, enabling row parallel decoding and reducing calculation complexity by adjusting row and column correspondences, while incorporating orthogonal relationships between extended nodes to enhance decoding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If LDPC base graph is obtained by extending high code rate to low code rate, then code rate flexibility is improved, but calculation complexity increases
Solution Approach 1:
The LDPC base graph is segmented into non-extended columns and extended columns. The non-extended columns maintain the original structure from the high code rate base graph, while extended columns are added to support low code rates. This segmentation allows the system to maintain calculation complexity for the core functionality while adding flexibility through optional extensions.
Solution Approach 2:
The patent extracts the essential non-extended columns from the original base graph that maintain the same calculation complexity characteristics, and separates them from the extended columns. By taking out and preserving only the necessary components, the system achieves code rate flexibility without proportionally increasing calculation complexity.
2Productivity
If traditional LDPC code structure is used, then decoding implementation is simple, but parallel decoding of entire rows is not supported
Solution Approach 1:
The patent introduces a new dimensional organization to the LDPC base graph by arranging columns into non-extended and extended groups with specific row parallelization structures. This dimensional reorganization enables entire rows to be decoded in parallel while maintaining a structured format that can be implemented with modified but manageable complexity.
3Reliability
If 802.11ay LDPC code is used, then one check matrix is stored per code rate, but flexible code rate and IR-HARQ mechanism are not supported
Solution Approach 1:
The patent creates a universal LDPC base graph structure that can serve multiple code rates through the non-extended and extended column configuration. This single base graph structure supports both flexible code rate selection and IR-HARQ mechanisms, replacing the need for separate check matrices for each code rate while maintaining reliability requirements.
Data Source
AI summary
This application provides an LDPC base graph construction manner. An LDPC base graph may be obtained based on a storage matrix and indication information that indicates a correspondence between rows of the storage matrix or a correspondence between rows of the expected LDPC base graph. In addition, in a process of obtaining the LDPC base graph, a total quantity of edges that correspond to non-extended columns and that are in a Tanner graph may not be changed. Therefore, the manner provided in this application helps maintain calculation complexity of an LDPC code, and in particular, helps reduce calculation complexity of an LDPC code in a scenario in which a high code rate is extended to a low code rate, to improve decoding efficiency.