LDPC Matrix Encoding for High-Block SSD Error Correction

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Solution Overview

Problem

Current LDPC code construction methods are inadequate for handling higher block lengths in solid state drive (SSD) systems, requiring efficient encoding methods and simple coding structures to achieve robust error-correcting performance and scalable code rates.

Innovation Solution

The development of new LDPC matrices based on algebraic relations, specifically constructing matrices H as [A|B] without a generator matrix, where A and B are designed to facilitate on-the-fly encoding, ensuring full rank and absence of short cycles, and using special linear group and Galois field-based structures for error correction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traditional LDPC code construction methods are used, then error correction capability is maintained, but encoding efficiency deteriorates and memory requirements increase for higher block lengths

Engineering Contradiction:
Improveencoding efficiencyVSAvoidmemory requirements
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The LDPC code is segmented into multiple blocks, where each block can be encoded independently. This segmentation allows the encoder to process data in smaller chunks rather than requiring memory for the entire block length, thus improving encoding efficiency while reducing memory requirements for higher block lengths.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent pre-computes and stores only the essential parity-check matrix structures and encoding parameters rather than the entire generator matrix. This preliminary action reduces memory requirements while maintaining the ability to efficiently encode higher block lengths by using the pre-computed structures.

Inventive Principle:
Principle #10Preliminary action

2Quantity of substance

If larger block lengths are used to increase storage capacity, then storage capacity is improved, but encoding complexity increases

Engineering Contradiction:
Improvestorage capacityVSAvoidencoding complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

Large block lengths are divided into smaller manageable segments that can be encoded using simplified procedures. This segmentation maintains storage capacity while reducing the complexity of encoding operations by breaking down the large-scale problem into smaller, more tractable sub-problems.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the parameter representation from full generator matrices to compact parity-check matrix structures and encoding parameters. This parameter change allows larger block lengths to be handled with reduced encoding complexity by using more efficient mathematical representations.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If conventional encoding schemes are used, then data integrity is maintained, but throughput is reduced due to interleaver requirements

Engineering Contradiction:
ImprovethroughputVSAvoiddata integrity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent extracts and eliminates the interleaver component from the conventional encoding scheme. By taking out the interleaver, throughput is improved as the encoding pipeline can operate continuously without the buffering and reordering operations that interleavers require, while data integrity is maintained through the inherent error correction capabilities of the LDPC code structure.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentUS9203434B1Systems and methods for improved encoding of data in data storage devices
Publication Date: 2015.12.01 WESTERN DIGITAL TECHNOLOGIES INC
  • US9203434B1 patent drawing
  • US9203434B1 patent drawing
  • US9203434B1 patent drawing

AI summary

Some embodiments of the invention are directed to systems and methods for an optimized and efficient encoding scheme that can accommodate higher block lengths of data. Some embodiments generally relate to: (1) coding structures for a new class of LDPC matrices based on algebraic relations, and (2) encoding method that achieves the R=1−k/n exact bound on code rate. In addition, in some embodiments, the coding structures efficiently create matrices with excellent error-correcting properties and are devoid of short cycles (leading to robust performance). The implementations of the coding structures are scalable over a range of code rates and block lengths.