Vertical Layered FAID for High-Throughput LDPC Decoding

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Solution Overview

Problem

Conventional LDPC decoders face challenges in achieving low error rates and high throughput while maintaining low hardware costs, with existing approaches often requiring significant resources and power, and previous solutions focused primarily on FAIDs for LDPC codes with fixed column-weight dv=3, which are not sufficient for storage applications.

Innovation Solution

The implementation of vertical layered finite alphabet iterative decoding, which processes messages between variable and check nodes using a parity-check matrix composed of row and column blocks, allowing for flexible hardware architectures and improved error correction capabilities across both fixed and variable column-weight LDPC codes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional LDPC decoders use traditional decoding algorithms, then error correction capability is maintained, but hardware resources and power consumption increase significantly

Engineering Contradiction:
Improveerror correction capabilityVSAvoidhardware resources
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The parity-check matrix H is divided into multiple column blocks, where each column block contains multiple sub-matrices. The decoding process is segmented to process one column block at a time, allowing the hardware to focus on smaller, manageable subsets of the full code structure. This segmentation enables reuse of computational resources across different column blocks, reducing overall hardware requirements while maintaining full error correction capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The decoding algorithm employs periodic action by repeatedly processing column blocks in a systematic sequence. The same hardware structure is applied periodically to each column block, with results accumulated across iterations. This periodic processing approach allows limited hardware resources to achieve the functionality of a larger system through repeated application over time.

Inventive Principle:
Principle #19Periodic action

2Measurement precision

If conventional LDPC decoders process the entire parity-check matrix simultaneously, then decoding accuracy is improved, but throughput is limited and resource usage increases

Engineering Contradiction:
Improvedecoding accuracyVSAvoidthroughput
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The parity-check matrix processing is segmented into column block-level operations. Each column block is processed independently and completely before moving to the next column block. This segmentation enables pipelining and parallel processing of different column blocks, significantly increasing throughput while ensuring that each block receives the full attention needed for accurate decoding.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The decoding process maintains continuity of useful action by systematically processing column blocks in sequence without idle periods. While one column block is being processed, preparation for the next block can occur simultaneously, ensuring continuous utilization of hardware resources. The iterative nature of the algorithm ensures that decoding accuracy improves with each complete pass through all column blocks.

Inventive Principle:
Principle #20Continuity of useful action

3Device complexity

If previous FAID solutions are used for LDPC codes with fixed column-weight dv=3, then implementation is simplified, but error correction performance is insufficient for storage applications

Engineering Contradiction:
Improveimplementation complexityVSAvoiderror correction performance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The decoding algorithm is designed with universality to handle both fixed column-weight (dv=3) and variable column-weight LDPC codes using the same hardware structure and processing logic. The column block processing approach and sub-matrix operations remain consistent regardless of the specific code parameters, allowing a single implementation to serve multiple code types and applications, including storage systems requiring higher error correction performance.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentUS11381255B2Vertical layered finite alphabet iterative decoding
Publication Date: 2022.07.05 CODELUCIDA INC
  • US11381255B2 patent drawing
  • US11381255B2 patent drawing
  • US11381255B2 patent drawing

AI summary

This invention presents a method and apparatus for vertical layered finite alphabet iterative decoding of low-density parity-check codes (LDPC) which operate on parity check matrices that consist of blocks of sub-matrices. The iterative decoding involves passing messages between variable nodes and check nodes of the Tanner graph that associated with one or more sub-matrices constitute decoding blocks, and the messages belong to a finite alphabet. Various embodiments for the method and apparatus of the invention are presented that can achieve very high throughputs with low hardware resource usage and power.