Variable-Rate LDPC Parity Matrix Design for Signal Transmission
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Solution Overview
Problem
Next-generation communication systems require support for variable coding rates to enhance data throughput, but existing block LDPC codes are limited in coding rate, making it difficult to implement optimal performance due to restrictions such as cycle structure in factor graphs and hardware implementation.
Innovation Solution
A signal transmission and reception apparatus and method that generate child parity check matrices based on a parent parity check matrix to support variable coding rates, using a concatenation of semi-systematic block LDPC codes and single parity check codes to optimize noise threshold performance and enable coding rates from ½ to ¾.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If block LDPC codes are used for high-speed data transmission, then error correction performance is improved, but coding rate flexibility deteriorates
Solution Approach 1:
The parity check matrix is segmented into multiple sub-matrices (first sub-parity check matrix and second sub-parity check matrix), allowing the system to selectively use different segments for different coding rates. This segmentation enables flexible adaptation while maintaining the error correction properties of LDPC codes.
Solution Approach 2:
The system dynamically selects and configures parity check matrices based on the required coding rate. By having a pool of pre-defined parity check matrices with different rates (1/2, 2/3, 3/4) and dynamically selecting appropriate ones, the system achieves both reliability and coding rate flexibility.
2Productivity
If variable coding rates are supported, then data throughput is improved, but system complexity increases
Solution Approach 1:
Multiple parity check matrices for different coding rates are pre-defined and stored in the system. When a specific coding rate is needed, the system simply retrieves the pre-configured matrix rather than generating it dynamically, significantly reducing computational complexity while supporting variable coding rates for high throughput.
Solution Approach 2:
The system changes parameters (coding rate, parity check matrix selection) based on transmission conditions. By having pre-configured matrices with different parameters (rates of 1/2, 2/3, 3/4), the system can adapt to different throughput requirements without complex real-time calculations.
3Reliability
If optimal degree distribution is calculated using density evolution scheme, then coding rate is reduced, but implementation difficulty increases
Solution Approach 1:
Instead of performing complex density evolution calculations to determine optimal degree distributions, the patent uses pre-defined parity check matrices that have been optimized beforehand. This copying of pre-optimized structures achieves near-optimal noise threshold performance while dramatically simplifying implementation.
Solution Approach 2:
The patent replaces complex computational processes (density evolution scheme) with simple, pre-computed structures (standardized parity check matrices). These pre-defined matrices serve as disposable, pre-optimized solutions that eliminate the need for complex real-time calculations while maintaining optimal performance.
Data Source
AI summary
Provided are an apparatus and method for transmitting/receiving signal, supporting a variable coding rate, in a communication system. The method includes receiving an information vector, generating a child parity check matrix based on a parent parity check matrix according to a coding rate to be applied for generating a block Low Density Parity Check (LDPC) codeword using the information vector, and encoding the information vector into the block LDPC codeword according to the child parity check matrix.