LDPC Rate Matching Using Circular Buffer Systematic Bit 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 in their implementation, particularly when shortening, puncturing, and repetition are applied to achieve specific code rates and block lengths, leading to performance issues.
Innovation Solution
The method involves generating a codeword vector using LDPC codes and performing circular buffer-based rate matching, which includes puncturing systematic bits, to produce coded bits for transmission, allowing for flexible adjustment of code rates and block lengths without the need for separate procedures for shortening, puncturing, and repetition.
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 code configuration is improved, but device complexity and implementation difficulty 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 systematic process that selects and applies the appropriate operation based on the desired code rate and block length requirements, thereby reducing implementation complexity while maintaining flexibility
Solution Approach 2:
The patent creates a universal rate matching procedure that can handle multiple code configuration requirements (different code rates and block lengths) through a single unified mechanism. This multi-functional approach allows the same procedure to perform shortening, puncturing, and repetition operations as needed, eliminating the need for multiple specialized procedures
2Adaptability or versatility
If existing rate matching methods are implemented as specified in 802.11n, then standard compliance is improved, but implementation clarity and effectiveness deteriorate
Solution Approach 1:
The patent segments the rate matching process into clear, distinct steps with well-defined operations. By breaking down the unified procedure into manageable segments (such as determining the operation type, applying the operation, and managing the codeword), the implementation becomes more transparent and easier to execute while still achieving standard compliance
Solution Approach 2:
The patent performs preliminary analysis to determine which rate matching operation (shortening, puncturing, or repetition) is needed before executing the actual rate matching. This preliminary determination step clarifies the implementation path and ensures that the correct operation is applied, improving both clarity and effectiveness
3Productivity
If circular buffer-based rate matching punctures systematic bits, then rate matching efficiency is improved, but information reliability may worsen
Solution Approach 1:
The patent carefully controls which systematic bits are punctured and under what conditions, changing the parameters of the puncturing operation to optimize the balance between efficiency and reliability. By adjusting the selection criteria for punctured bits based on the specific code configuration and transmission requirements, the system maintains efficiency while minimizing reliability degradation
Data Source
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.