Variable-Length LDPC Encoding Through Shortening and Puncturing
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Solution Overview
Problem
Conventional LDPC encoding systems generate codewords of fixed length, limiting their ability to adapt to varying data transmission requirements in high-speed digital communication systems, which necessitate larger data processing, higher-speed data processing, and higher reliability.
Innovation Solution
The method involves shortening or puncturing LDPC codes with a fixed length to generate codes of variable length, adjusting the ratio of shortened bits to punctured bits using predetermined rules, and applying these techniques for encoding and decoding in communication systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If LDPC codes of fixed length are used, then encoding and decoding can be performed with simple structures, but the system cannot adapt to varying data transmission requirements
Solution Approach 1:
The patent applies dynamics by enabling the LDPC code length to be dynamically adjusted through shortening and puncturing operations. The base code is of fixed length, but by selectively removing (shortening) or not transmitting (puncturing) specific bits, the effective code length adapts to different data transmission requirements while maintaining a relatively simple base encoding structure
Solution Approach 2:
The patent changes the parameter of code length by applying shortening and puncturing techniques to the base LDPC code. By controlling the number of shortened bits and punctured bits, the system generates LDPC codes with different lengths and code rates, thereby adapting to varying transmission requirements without redesigning the entire encoding structure
2Adaptability or versatility
If shortening and puncturing are applied to generate variable length codes, then the system can support different data transmission needs, but the complexity of code generation and control increases
Solution Approach 1:
The patent applies preliminary action by pre-defining the shortening and puncturing patterns based on the desired code length and rate. The positions of bits to be shortened and punctured are determined in advance according to predetermined rules, which simplifies the control complexity during actual encoding operations by avoiding real-time complex calculations
Solution Approach 2:
The patent segments the base LDPC code into different portions that can be selectively shortened or punctured. By dividing the code structure and applying different operations to different segments, the system achieves variable length codes while maintaining organized control over the encoding process
Data Source
AI summary
An apparatus and a method for channel encoding/decoding in a communication system are provided. The apparatus and the method generate LDPC-encoded blocks with various lengths from an LDPC code with fixed length in a communication system using a Low-Density Parity-Check (LDPC) code. The apparatus and the method perform shortening using a predetermined number of shortened bits and perform LDPC encoding. The apparatus and the method apply predetermined rules according to the predetermined number of shortened bits and determine the number of bits to be punctured, and perform puncturing based on the determined number of punctured bits.