Protograph LDPC Parity-Check Matrix Layout for Low-Latency Decoding

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Solution Overview

Problem

Current wireless communication systems face challenges in achieving efficient low-density parity check (LDPC) coding for super ultra-reliable and low-latency communications, particularly in 5G wireless communication systems, where decoding delay and complexity are significant issues.

Innovation Solution

The method involves obtaining a protomatrix related to a protograph, generating permuted vectors based on weights and lifting factors, distributing these vectors to create lifted submatrices, and generating a base graph to produce a parity check matrix for LDPC coding, which maximizes parallelism in layered decoding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional LDPC coding methods are used in 5G wireless communication systems, then channel coding performance is achieved, but decoding delay and processing time increase

Engineering Contradiction:
Improvechannel coding performanceVSAvoiddecoding delay
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The parity check matrix is segmented into multiple submatrices through the lifting process, where each submatrix corresponds to a specific element of the protomatrix. This segmentation enables parallel processing during decoding operations, reducing overall decoding delay while maintaining the error correction performance of the complete LDPC code structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transforms the one-dimensional parity check matrix into a two-dimensional structure through the lifting factor Z, creating a base graph that is then expanded into a larger parity check matrix. This dimensional transformation allows for optimized decoding algorithms that can process multiple bits simultaneously, reducing decoding time while preserving coding performance.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If conventional LDPC coding methods are used in 5G wireless communication systems, then channel coding performance is achieved, but processing complexity increases

Engineering Contradiction:
Improvechannel coding performanceVSAvoidprocessing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

By dividing the large parity check matrix into smaller submatrices through lifting, the patent enables modular processing where each submatrix can be handled independently or in parallel. This segmentation reduces the computational complexity of individual processing steps while maintaining the overall coding performance through the coordinated operation of all submatrices.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs dynamic permuted vectors that can be adapted based on the specific requirements of the communication scenario. The lifting factor and permuted vectors can be adjusted to balance between processing complexity and performance requirements, allowing the system to optimize its operation dynamically based on channel conditions and traffic patterns.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS11784663B2Method and apparatus for performing encoding on basis of parity check matrix of low density parity check code generated from protograph in wireless communication system
Publication Date: 2023.10.10 LG ELECTRONICS INC
  • US11784663B2 patent drawing
  • US11784663B2 patent drawing
  • US11784663B2 patent drawing

AI summary

A method for performing low density parity check (LDPC) coding of a transmitter in a wireless communication system, according to the present disclosure, may comprise the steps of: acquiring a proto-matrix corresponding to a protograph; on the basis of weights and lifting factors of columns of the proto-matrix, acquiring one or more permuted vectors corresponding to each of the columns, a first permuted vector included in the one or more permuted vectors having been randomly generated; distributing the one or more permuted vectors for each row of a corresponding column; on the basis of the distributed one or more permuted vectors, acquiring a plurality of lifted sub matrices corresponding to a plurality of elements of the proto-matrix; generating a base graph on the basis of the plurality of lifted sub matrices; generating a parity check matrix (PCM) on the basis of the base graph; and performing LDPC coding by using the PCM.