Non-Binary LDPC Column Rotation for Varying Channel Conditions

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing data processing systems using Low Density Parity Check (LDPC) codes face suboptimal performance across varying channel conditions due to differences in error patterns at high and low channel bit densities, requiring multiple codes that increase complexity and size.

Innovation Solution

Applying column rotations to the parity check H-matrix or codewords allows a single non-binary LDPC code to perform effectively across different channel conditions by altering algebraic values without changing topology, enabling superior performance without the need for multiple codes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple LDPC codes are used to handle different channel conditions, then performance across varying channel conditions is improved, but device complexity and code size increase

Engineering Contradiction:

Improveperformance across channel conditionsVSAvoidcomplexity and size

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

A single non-binary LDPC code is designed to perform multiple functions by effectively handling different channel conditions (high bit density and low bit density) through algebraic modifications, eliminating the need for multiple separate codes and reducing system complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention changes algebraic parameters of the LDPC code by applying column rotations to the parity check H-matrix or codewords, which modifies the code's algebraic values while preserving its topological structure, enabling the same code to adapt to different channel conditions

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If a single LDPC code is used for all channel conditions, then device complexity is reduced, but performance under specific channel conditions deteriorates

Engineering Contradiction:

Improvecomplexity and sizeVSAvoidperformance under channel conditions

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The LDPC code is made dynamic by applying column rotations that can be adjusted based on channel conditions, allowing the code to adapt its algebraic properties in response to varying bit density conditions while maintaining a single code structure

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

By modifying algebraic values through column rotations of the H-matrix or codewords, the single LDPC code can change its parameters to optimize performance for different channel conditions without requiring multiple static codes

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9727419B2Non-binary low density parity check code column rotation

Publication Date: 2017.08.08 AVAGO TECHNOLOGIES INTERNATIONAL SALES PTE LTD

AI summary

An apparatus for processing data includes a storage medium operable to store encoded data, and a read channel circuit with a low density parity check encoder operable to encode data to generate the encoded data, and a low density parity check decoder operable to decode the encoded data retrieved from the storage medium. The read channel circuit is operable to perform a column rotation on the encoded data prior to storage and after retrieval before decoding.