Content-Aware SSD Decoding Using Data Pattern Parameters

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Solution Overview

Problem

Conventional soft Error Code Correction (ECC) decoders for solid state drives (SSDs) face issues with high bit flips, inaccurate estimation of underlying statistics, increased decoding latency, and power consumption due to incorrect decoding parameters, leading to potential data loss and reliability concerns.

Innovation Solution

The implementation of content-aware decoding methods that estimate data values using source and channel log-likelihood ratios, determine data pattern parameters, and perform decoding processes to improve correction capability, reduce latency, and optimize power consumption by leveraging underlying data statistics and patterns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional soft ECC decoders use default parameters assuming uniform distribution of data, then the decoder can operate without prior knowledge of data statistics, but the decoding accuracy deteriorates due to wrong estimation of underlying statistics

Engineering Contradiction:
Improvedecoder operation without prior knowledgeVSAvoiddecoding accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The system performs preliminary actions by collecting data samples during the write operation and estimating underlying statistics before the actual decoding process. This preliminary statistical estimation is stored and reused during subsequent read operations, eliminating the need to assume uniform distribution while avoiding the cost of real-time statistics collection during decoding.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system prepares correction capabilities in advance by estimating data statistics during the write phase and storing these estimates. When reading data, these pre-computed statistical estimates cushion against the uncertainties of unknown data distributions, preventing decoding failures before they occur.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Measurement precision

If the decoder adjusts parameters based on estimated statistics, then decoding accuracy may improve, but the number of bit flips increases leading to wrong estimation and potential decoding failure

Engineering Contradiction:
Improvedecoding accuracyVSAvoiddecoding success rate
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The system applies partial action by using a limited number of data samples collected during write operations to estimate statistics, rather than processing the entire data set. This partial estimation is sufficient to improve decoding accuracy without causing excessive bit flips that would lead to wrong statistics estimation.

Inventive Principle:
Principle #16Partial or excessive action

3Device complexity

If conventional decoders use inaccurate decoding parameters, then the device complexity remains low, but the power consumption increases and decoding latency increases

Engineering Contradiction:
Improvedecoder structureVSAvoidpower consumption
Core Design Contradiction:
Device complexityVSUse of energy by moving object

Solution Approach 1:

The system performs statistics estimation and parameter optimization in advance during the write operation, storing the results for later use. This preliminary action eliminates the need for complex real-time parameter adjustment mechanisms, maintaining low device complexity while reducing power consumption and latency during read operations.

Inventive Principle:
Principle #10Preliminary action

4Reliability

If the system collects data samples during write to estimate statistics, then the correction capability improves, but the write operation time increases

Engineering Contradiction:
Improveerror correction capabilityVSAvoidwrite operation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system uses a partial set of data samples collected during the write operation to estimate statistics, rather than processing the complete data set. This partial estimation provides sufficient correction capability while minimizing the time penalty during write operations.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS11251814B2Content aware decoding method and system
Publication Date: 2022.02.15 SANDISK TECHNOLOGIES LLC
  • US11251814B2 patent drawing
  • US11251814B2 patent drawing
  • US11251814B2 patent drawing

AI summary

A method and apparatus for obtaining data from a memory, estimating a probability of data values of the obtained data based on at least one of a source log-likelihood ratio and a channel log-likelihood ratio, wherein each bit in the obtained data has an associated log-likelihood ratio, determining at least one data pattern parameter for the data and performing a decoding process using the at least one data pattern parameters to determine a decoded data set.