Turbo Product Code Decoding With Miscorrection Detection

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Solution Overview

Problem

Turbo Product Codes (TPC) decoding in NAND-based storage devices face significant issues with miscorrection, where constituent codes incorrectly decode to a codeword different from the original, leading to increased bit-errors and reduced decoding success rates, especially at higher bit-error rates.

Innovation Solution

Implementing a miscorrection detection system that distinguishes between corrected and miscorrected decoding attempts, limiting the number of bit-flips in each decoding round to prevent miscorrection, and scheduling corrections based on the number of bit-flips required for each codeword, thereby reducing the probability of miscorrection and improving overall decoding performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a decoder corrects received sequences to the nearest codeword, then decoding speed is improved, but miscorrection occurs when the received sequence is closer to an incorrect codeword

Engineering Contradiction:

Improvedecoding speedVSAvoiddecoding accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by performing miscorrection detection before final codeword selection. The system pre-calculates syndrome values and determines potential miscorrection scenarios in advance, allowing the decoder to identify and avoid incorrect codewords before committing to a correction, thus maintaining both speed and accuracy

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary mechanism - the syndrome calculation and miscorrection detection logic - that acts as a mediator between the received sequence and the final codeword selection. This intermediary layer verifies whether a correction would be valid before applying it, preventing miscorrections while preserving the efficiency of nearest-codeword decoding

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the number of bit-flips is increased to correct more errors, then error correction capability is improved, but the probability of miscorrection increases

Engineering Contradiction:

Improveerror correction capabilityVSAvoidmiscorrection probability

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements feedback by using syndrome calculations to provide information about the actual error state back to the decoding process. The syndrome values feedback whether the received sequence is closer to the transmitted codeword or an incorrect codeword, allowing the system to adjust its correction strategy and avoid miscorrections even when multiple bit-flips are involved

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent applies preliminary anti-action by detecting potential miscorrections before they occur. The miscorrection detection mechanism identifies scenarios where increasing bit-flips would lead to incorrect corrections and takes preventive action by rejecting such correction paths, thereby counteracting the harmful effect of miscorrection before it can degrade reliability

Inventive Principle:

Principle #9Preliminary anti-action

Data Source

PatentUS9569302B1Decoding of turbo product codes using miscorrection detection

Publication Date: 2017.02.14 SK HYNIX INC

AI summary

Decoding using miscorrection detection is disclosed. A measure indicative of the number of proposed corrections included in a set of proposed corrections corresponding to one or more of a plurality of read values is received. The plurality of read values corresponds to a codeword. It is determined whether the number of proposed corrections is a permitted number of corrections.