LDPC Shortening and Puncturing via Parity Matrix Bit Grouping
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Solution Overview
Problem
In communication/broadcasting systems, existing technologies face challenges in maintaining optimized performance when shortening or puncturing bits of an LDPC code, particularly due to the complexity of selecting the appropriate bits to be shortened or punctured, which affects the reliability and efficiency of high-speed digital communication.
Innovation Solution
The proposed solution involves a method for selecting shortened and punctured bits in a communication/broadcasting system using a parity test matrix structure, where the parity test matrix is divided into partial matrices for information and parity bits, allowing for optimized bit selection and maintenance of performance through specific patterns and procedures for padding, puncturing, and encoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If bits are shortened or punctured to adapt to variable transmission requirements, then the adaptability of the communication system is improved, but the performance of the LDPC code deteriorates
Solution Approach 1:
The parity test matrix is divided into multiple column groups, where each group corresponds to a set of bits that can be independently selected for shortening or puncturing. This segmentation allows the system to adaptively adjust the codeword length by selecting specific column groups while maintaining the structural integrity and error-correcting performance of the LDPC code.
Solution Approach 2:
Different column groups within the parity test matrix are designed with different properties, allowing selective shortening or puncturing of specific groups based on transmission requirements. This local differentiation enables the system to maintain optimized performance by preserving critical bit groups while removing less critical ones, thus resolving the contradiction between adaptability and performance.
2Ease of operation
If the parity test matrix is divided into partial matrices for information and parity bits, then the ease of operation is improved, but the device complexity increases
Solution Approach 1:
The parity test matrix is divided into an information word partial matrix and a parity partial matrix, with the parity partial matrix further divided into multiple column groups. This segmentation simplifies the encoding process by allowing separate handling of information bits and parity bits, making it easier to perform shortening and puncturing operations on specific portions without affecting the entire codeword structure.
Solution Approach 2:
The parity test matrix is pre-divided into structured partial matrices with defined column groups before encoding begins. This preliminary structuring enables straightforward selection and processing of specific bit groups during transmission, reducing the operational complexity during actual encoding and transmission while maintaining systematic organization.
Data Source
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Figure 3A~3C
AI summary
An apparatus and a method for performing shortening and puncturing in case of performing encoding and decoding using a parity test matrix in a communication/broadcasting system are provided. In a method for operating a transmission end, the number of bits to be 0-paded is determined. The number of bit groups Npad where all bits are to be padded to 0 is determined. All bits inside 0-th to (Npad-1)-th bit groups indicated by a shortening pattern are padded to 0. Information bits are mapped to unpadded bit positions in Bose Chaudhuri Hocquenghem (BCH) information bits. The BCH information bits are BCH-encoded in order to generate LDPC information bits. The LDPC information bits are LDPC-encoded in order to generate a 0-padded codeword. Here, the shortening pattern is defined in a sequence of bit groups defined as 9, 8, 15, 10, 0, 12, 5, 27, 6, 7, 19, 22, 1, 16, 26, 20, 21, 18, 11, 3, 17, 24, 2, 23, 25, 14, 28, 4, 13, 29.