Rate-Compatible LDPC Coding Using Puncturing and Pruning
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Solution Overview
Problem
Current communication systems face challenges in supporting variable coding rates for LDPC codes, which limits their performance in high-capacity data transmission and error correction, especially in mobile communication systems where efficient coding and decoding are crucial.
Innovation Solution
A method and apparatus for encoding and decoding block Low Density Parity Check (LDPC) codes with variable coding rates are developed, utilizing specific design techniques such as shortening, puncturing, extending, and pruning schemes to create a parity check matrix that supports multiple coding rates with minimized coding complexity and optimized degree distribution in the factor graph.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LDPC codes are used for error correction in communication systems, then reliability of data transmission is improved, but device complexity increases due to the need for iterative decoding processes and factor graph management
Solution Approach 1:
The patent segments the LDPC code into multiple sub-codes with different coding rates. Each sub-code can be independently decoded, reducing the overall decoding complexity while maintaining high reliability through selective use of sub-codes based on channel conditions
Solution Approach 2:
The patent implements dynamic selection of coding rates and sub-codes based on channel conditions. The system dynamically adjusts which sub-codes to use and at what coding rates, optimizing the balance between reliability and complexity for different transmission scenarios
2Adaptability or versatility
If variable coding rates are supported for LDPC codes, then adaptability to different channel conditions is improved, but device complexity increases due to multiple parity check matrices and rate compatibility requirements
Solution Approach 1:
The patent designs a universal LDPC code structure where a single base code can operate at multiple coding rates through systematic puncturing patterns. This multi-functional design allows the same encoder and decoder to support variable coding rates without requiring separate implementations for each rate
Solution Approach 2:
The patent changes the effective coding rate parameter by selectively puncturing different portions of the coded data rather than changing the fundamental code structure. This allows smooth transition between coding rates while maintaining the same underlying LDPC code framework
3Productivity
If high-capacity data transmission is implemented, then productivity is improved, but loss of information increases due to errors caused by noise and interference in wireless channels
Solution Approach 1:
The patent implements feedback mechanisms where the receiver detects errors in high-capacity data transmission and requests retransmission of specific erroneous packets. This selective retransmission feedback loop maintains high productivity while minimizing information loss through efficient error correction
Data Source
AI summary
A method for encoding a rate-compatible block Low Density Parity Check (LDPC) code. The method includes designing specific LDPC codes for a predetermined number of coding rates, and generating a pruning pattern by comparing information node degrees of the predetermined number of LDPC codes; matching check node degrees of the predetermined number of LDPC codes; generating a predetermined number of puncturing patterns according to the check node degree when the matched check node degree is calculated; determining whether a first condition given for the generated puncturing patterns is satisfied; and determining the generated puncturing patterns as rate-compatible puncturing patterns when the puncturing patterns satisfy the first condition.