LDPC Rate Matching Using Circular Buffers and Systematic Bit Puncturing
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Solution Overview
Problem
Existing rate matching methods for LDPC codes, such as those in 802.11n, are unclear on how to perform rate matching when some systematic bits are punctured by design, making it difficult to achieve efficient code performance.
Innovation Solution
A circular buffer-based rate matching method is introduced, where systematic bits are punctured and parity bits are managed to produce coded bits for transmission, allowing for flexible code rate adjustment through shortening, puncturing, and repetition without needing separate procedures for each method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate procedures are used for shortening, puncturing, and repetition in rate matching, then code performance can be optimized for specific scenarios, but device complexity and procedural overhead increase
Solution Approach 1:
The patent merges shortening, puncturing, and repetition operations into a unified rate matching procedure. The encoder uses a single base matrix and applies all three operations through one integrated process, eliminating the need for separate procedural implementations while maintaining the performance benefits of each technique
Solution Approach 2:
The unified rate matching procedure is designed to perform multiple functions simultaneously - it can shorten code length, puncture coded bits, and repeat information bits all within the same encoding framework. This multi-functional approach allows the system to adapt to different transmission requirements without requiring separate specialized procedures
2Reliability
If different PCMs are used for each alternative of block lengths and rates, then code performance can be optimized for specific parameters, but productivity and efficiency decrease
Solution Approach 1:
The patent employs a single universal base matrix that can generate codewords for multiple block lengths and code rates through the unified rate matching procedure. This eliminates the need to store and switch between multiple different PCMs, significantly improving encoding efficiency while maintaining optimized performance for various transmission parameters
3Reliability
If systematic bits are punctured by design, then code performance can be improved for specific scenarios, but clarity and ease of operation regarding rate matching procedures deteriorate
Solution Approach 1:
The patent segments the codeword into systematic bits and parity bits, with the unified rate matching procedure explicitly identifying and handling punctured systematic bits separately. This segmentation provides clear procedural guidance on which bits to puncture and how to manage the remaining bits, improving ease of operation while maintaining performance benefits
Data Source
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AI summary
A method of producing a set of coded bits from a set of information bits for transmission between a first node (110, 115) and a second node (110, 115) in a wireless communications system (100), the method comprises generating (904) a codeword vector by encoding the set of information bits with a low-density parity-check code, wherein the codeword vector is composed of systematic bits and parity bits. The method comprises performing (908) circular buffer-based rate matching on the generated codeword vector to produce the coded bits for transmission, wherein the circular buffer-based rate matching comprises puncturing a first plurality of systematic bits.