LDPC Base Matrix Permutation for High-Rate Code Reliability
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Solution Overview
Problem
Current LDPC codes face performance challenges at high code rates due to puncturing effects, which impact their reliability and efficiency in communications systems, particularly in fifth-generation mobile communications.
Innovation Solution
The method involves encoding and decoding using a low-density parity-check (LDPC) matrix with a base matrix structure that includes permutations of parity check columns, specifically adjusting the column weights and positions to optimize code rate and performance, by permuting groups of bits in the parity check columns to reduce the number of punctured non-zero entries and enhance decoding reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If puncturing is performed on the encoded bit sequence to achieve high code rates, then the code rate is improved, but the performance of the LDPC code deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-permuting the parity check columns in the LDPC base matrix before encoding. Specifically, columns with weight 2 in the core matrix part are arranged in a bidiagonal structure, and columns with weight greater than 2 are positioned to minimize puncturing impact. This preliminary arrangement ensures that when puncturing is performed to achieve high code rates, the remaining bits maintain optimal error correction capability, thus resolving the contradiction between achieving high code rates and maintaining LDPC code performance
Solution Approach 2:
The patent applies local quality by differentiating the treatment of different column types in the LDPC base matrix. Columns are categorized by their weight (weight 2, weight >2, weight 1), and each category is assigned a specific position and permutation strategy. For example, weight-2 columns are placed in bidiagonal structures while weight-1 columns are positioned in specific locations to preserve their error detection capability. This localized optimization of different matrix regions allows the system to achieve high code rates through selective puncturing while maintaining overall code performance
Data Source
AI summary
This application discloses an information processing method and apparatus, a communications device, and a communications system. The method includes: encoding an input sequence by using a low density parity check LDPC matrix to obtain a bit sequence D, where a base matrix of the LDPC matrix is represented by a matrix of m rows and n columns, each column corresponds to a group of Z continuous bits in the bit sequence D, and both n and Z are integers greater than 0; and obtaining an output bit sequence based on a bit sequence V, where the bit sequence V is obtained by permuting groups of bits corresponding to at least two parity check columns in the bit sequence D.