QC-LDPC Rate Matching Using Circular Buffer Puncturing
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Solution Overview
Problem
Existing rate matching methods for LDPC codes, such as those used in 802.11n, are inefficient and unclear, particularly when applying shortening, puncturing, and repetition to achieve desired code rates and block lengths, and there is a lack of a simple and effective method for performing rate matching in these scenarios.
Innovation Solution
The implementation of circular buffer-based rate matching, which allows for the production of coded bits by puncturing systematic bits and utilizing redundancy versions, enabling flexible rate matching without the need for separate procedures for shortening, puncturing, and repetition, and allowing for arbitrary code sizes (Ktx, Ntx) to be achieved using a single procedure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate procedures for shortening, puncturing, and repetition are used to achieve different code rates and block lengths, then flexibility in rate matching is improved, but device complexity and procedure complexity increase
Solution Approach 1:
The patent combines shortening, puncturing, and repetition operations into a unified rate matching procedure. Instead of implementing separate procedures for each operation, the invention integrates them into a single framework that can handle all three operations through a common algorithmic approach, thereby reducing procedural complexity while maintaining flexibility.
Solution Approach 2:
The patent creates a universal rate matching procedure that can perform multiple functions (shortening, puncturing, and repetition) through a single unified method. This multi-functional approach allows the same procedure to adapt to different code rates and block lengths without requiring separate specialized procedures for each operation.
2Adaptability or versatility
If existing rate matching methods are used for LDPC codes in 802.11n, then code rate adaptation is achieved, but performance loss occurs due to inefficiency and unclear procedures
Solution Approach 1:
The patent optimizes rate matching by carefully controlling which parameters are changed and how. It systematically manages the modification of code block size and code rate through coordinated application of shortening, puncturing, and repetition operations, ensuring that parameter changes are made in an optimized sequence and manner to minimize performance degradation.
Solution Approach 2:
The patent applies preliminary actions by pre-determining the optimal combination of shortening, puncturing, and repetition operations before actual transmission. The method calculates and prepares the rate matching configuration in advance based on the desired code rate and block length, allowing the system to avoid suboptimal decisions during real-time operation and thereby reducing performance loss.
3Reliability
If different PCMs are used for each alternative of block lengths and rates, then code optimization is improved, but productivity decreases due to inefficiency
Solution Approach 1:
The patent employs a universal rate matching procedure that can work with a single base PCM to generate multiple different code rates and block lengths. This eliminates the need to store and process multiple different PCMs for different transmission parameters, thereby improving system efficiency and productivity while maintaining code optimization through the unified procedure.
Solution Approach 2:
The patent efficiently manages computational resources by discarding intermediate results that are not needed for the current transmission parameters and recovering/reusing computational patterns from previous operations. The unified rate matching procedure allows the system to reuse the same base PCM and computational framework across different code rates and block lengths, reducing redundant processing and improving overall productivity.
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.