LDPC Circular Buffer Rate Matching for Flexible Code Rates
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Solution Overview
Problem
Existing rate matching methods for LDPC codes, such as those used in 802.11n, are unclear and inefficient, particularly in applying shortening, puncturing, and repetition to achieve desired code rates and block lengths, leading to performance issues in wireless communications.
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 the desired code rates and block lengths can be obtained, but the system complexity increases and performance loss occurs
Solution Approach 1:
The patent combines shortening, puncturing, and repetition operations into a single unified rate matching procedure. The encoder applies all three operations simultaneously during the encoding process rather than sequentially, which reduces procedural complexity while maintaining the ability to achieve various code rates and block lengths. This merging of operations resolves the contradiction by eliminating the need for separate procedures.
Solution Approach 2:
The unified rate matching procedure serves multiple functions: it performs shortening, puncturing, and repetition all in one process. This multi-functional approach allows the system to adapt to different code rates and block lengths without requiring separate specialized procedures for each operation, thereby reducing complexity while maintaining versatility.
2Adaptability or versatility
If traditional rate matching methods are used, then code rates and block lengths can be adjusted, but performance loss occurs in wireless communications
Solution Approach 1:
The patent applies shortening, puncturing, and repetition operations during the encoding process itself, before transmission. This preliminary application of rate matching operations ensures that the coded bits are optimally prepared for transmission, improving reliability by avoiding performance loss that occurs with traditional post-encoding rate matching methods.
3Adaptability or versatility
If multiple separate rate matching operations are performed, then desired code parameters can be achieved, but the processing time and complexity increase
Solution Approach 1:
By merging shortening, puncturing, and repetition into a single simultaneous operation during encoding, the patent eliminates the sequential processing time required for separate operations. This unified approach maintains code parameter flexibility while significantly reducing the time required to perform rate matching.
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.