Multi-Bit Data Encoding with Partial ECC for Flash Memory

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Solution Overview

Problem

Existing error-correcting code methods in semiconductor memory devices reduce the number of information bits per cell, limiting storage capacity due to the use of parity bits for error correction.

Innovation Solution

A method that determines the range of an error pattern in multi-bit level data, encodes only the M-bit level of a P-bit level, and excludes encoding the (P-M) bit level, using a mapping table to map transmission symbols to P-bit levels and minimizing Hamming distance between binary vectors, thereby increasing the average information bit number per cell.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If error-correcting codes with parity bits are used in multi-bit flash memory devices, then data errors can be detected and corrected, but the number of information bits that can be stored in each cell is reduced

Engineering Contradiction:

Improveerror correction capabilityVSAvoidnumber of information bits per cell

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The P-bit level data is segmented into M encoded bits and (P-M) unencoded bits. The encoding operation is applied only to the M-bit portion while the (P-M) bit portion remains unencoded, thereby reducing the overall impact of parity bits on storage capacity while maintaining error correction capability for the encoded portion.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the P-bit level data are treated differently: the M-bit level is encoded with error correction while the (P-M) bit level is left unencoded. This local differentiation allows the system to optimize error protection for critical data while maximizing storage capacity for other data, resolving the contradiction between reliability and storage quantity.

Inventive Principle:

Principle #3Local quality

2Reliability

If all P-bit levels are encoded with error correction, then data reliability is improved, but the storage capacity of the flash memory device is reduced

Engineering Contradiction:

Improvedata accuracyVSAvoidstorage capacity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

Instead of applying error correction encoding to all P-bit levels, the invention applies encoding only partially to the M-bit level while leaving the (P-M) bit level unencoded. This partial action approach maintains sufficient data accuracy for the encoded portion while preserving storage capacity that would otherwise be consumed by redundant parity bits across all levels.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS8656258B2Method of encoding and decoding multi-bit level data

Publication Date: 2014.02.18 SAMSUNG ELECTRONICS CO LTD

AI summary

A method of encoding multi-bit level data includes: determining a range of an error pattern generated according to a transmission symbol, encoding an M-bit level of a P-bit level corresponding to the transmission symbol based on the range of the error pattern, and excluding encoding of a P-M bit level of the P-bit level. The variable P is a natural number of a value at least two, and the variable M is a natural number less than P.