Raptor-Like LDPC Base Graph Signaling Across Code Rate Ranges
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Solution Overview
Problem
Raptor-like LDPC base graphs in 5G communications systems face challenges in ensuring encoding and decoding performance across a wide range of code lengths and code rates, failing to effectively support both high and low code-rate encoding and decoding.
Innovation Solution
A data transmission method that allows a base station to select and indicate a target Raptor-like LDPC base graph to a terminal device from a set of available graphs, based on specific requirements such as code rate, code length, and service type, using modulation and coding scheme (MCS) indexes and lifting factors, to optimize encoding and decoding performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single Raptor-like LDPC base graph is used to support a wide range of code lengths and code rates, then the system can accommodate various transmission requirements, but the encoding and decoding performance cannot be ensured for code blocks with different lengths and code rates
Solution Approach 1:
The patent divides a single base graph into multiple sub-graphs, where each sub-graph is optimized for specific code length and code rate ranges. This segmentation allows the system to maintain high encoding and decoding performance for different transmission conditions while supporting a wide overall range of parameters.
Solution Approach 2:
The patent introduces dynamic selection of base graphs based on actual transmission conditions (code length, code rate, channel quality). The system can adaptively choose the most appropriate base graph for current requirements, optimizing performance dynamically rather than using a fixed single base graph.
2Reliability
If multiple Raptor-like LDPC base graphs are used to optimize encoding and decoding performance for different code lengths and code rates, then the performance is improved, but the signaling overhead and system complexity increase
Solution Approach 1:
The patent designs base graphs with universal structures that can serve multiple code length and code rate requirements. Each base graph is constructed to be adaptable across different scenarios, reducing the total number of distinct base graphs needed while maintaining performance optimization.
Solution Approach 2:
The patent uses parameter-based identification and selection of base graphs, where base graphs are distinguished by key parameters (such as lifting factors, column weights) rather than completely different structures. This allows efficient selection and representation, reducing signaling overhead while maintaining performance differentiation.
Data Source
AI summary
This application provides a data transmission method, a base station, and a terminal device. The method includes: determining, by a base station, a target base graph in N Raptor-like low-density parity-check (LDPC) base graphs; and sending, by the base station, indication information to a terminal device, where the indication information is used to indicate the terminal device to use the target base graph to perform LDPC encoding and decoding. Based on the foregoing technical solution, the base station may determine a target base graph in a plurality of Raptor-like LDPC base graphs that may be used to perform LDPC encoding and decoding, and indicate the target base graph to the terminal device. Further, for one code rate or one code length, the base station may select different base graphs as required.