Non-Binary LDPC Protograph Rate Adaptation for Short Packets
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional LDPC encoding methods face challenges in achieving improved performance, especially in ultra-reliable and low-latency communication scenarios, where rate-compatible non-binary LDPC codes are required for efficient channel coding in short packet regimes.
Innovation Solution
A method for supporting rate-compatible non-binary LDPC codes is implemented by obtaining a kernel part with specific check and variable nodes, setting the degree of each variable node to 2, and generating a protograph for different code rates, allowing for efficient extension to higher or lower rates while maintaining improved decoding thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional LDPC encoding methods are used, then the basic linear block code operation is maintained, but the performance is insufficient for ultra-reliable and low-latency communication scenarios
Solution Approach 1:
The LDPC code is segmented into a kernel part and an extension part. The kernel part contains the essential structure with variable nodes of degree 2, while the extension part allows for rate adaptation. This segmentation enables the code to maintain core decoding performance while adapting to different code rates through selective extension.
Solution Approach 2:
The invention changes the degree parameter of variable nodes in the kernel part to 2, which fundamentally alters the decoding threshold characteristics. This parameter change improves the decoding performance and enables better waterfall performance across different code rates, making the code suitable for ultra-reliable communication scenarios.
2Reliability
If the degree of variable nodes in the kernel part is set to 2, then the decoding threshold is improved and error floors are minimized, but the code structure becomes more constrained
Solution Approach 1:
By segmenting the code into kernel and extension parts with specific structural requirements only in the kernel, the invention maintains simplicity where possible while enforcing constraints only where necessary for performance improvement. The degree-2 constraint is applied only to kernel variable nodes, not throughout the entire code structure.
Solution Approach 2:
The degree-2 constraint is applied locally to variable nodes in the kernel part rather than globally to all variable nodes. This local application of the constraint achieves the desired decoding threshold improvement without unnecessarily complicating the entire code structure, allowing flexibility in the extension part.
3Adaptability or versatility
If a protograph is generated for different code rates based on the kernel part, then rate compatibility is achieved, but the generation process becomes more complex
Solution Approach 1:
The kernel part is designed in advance with the optimal degree-2 structure established before rate adaptation is needed. This preliminary design of the core structure eliminates the need for complex real-time optimization when generating protographs for different code rates, as the kernel provides a stable foundation for extension.
Solution Approach 2:
The kernel part with degree-2 variable nodes serves as a universal foundation that can generate protographs for multiple different code rates. This single kernel structure performs the multi-function of supporting various code rates (e.g., 1/2, 2/3, 3/4) through systematic extension, reducing the need for separate designs for each rate.
Data Source
AI summary
A method for supporting a rate-compatible non-binary LDPC code, performed by a wireless device, according to the present embodiment, comprises the steps of: acquiring a kernel part comprising a plurality of first check nodes and a plurality of first variable nodes, the kernel part having a predetermined first code rate applied thereto, and the level of each of the plurality of first variable nodes included in the kernel part being set to 2; and generating, on the basis of the kernel part, a protograph having a second code rate, when a change from the first code rate to the second code rate is required.