SSD LDPC Decoding Using Syndrome Weight and Read Threshold Search
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Solution Overview
Problem
Conventional Low-Density Parity Check (LDPC) error correction in Solid State Drive (SSD) storage devices is inefficient, leading to extended error correction times and operational interference, due to sub-optimal read voltage thresholds and unnecessary error correction stages.
Innovation Solution
A syndrome-weight-based error correction system that performs hard decoding operations using initial read voltage thresholds, determines optimal second read voltage thresholds, and initiates soft decoding if the first syndrome weight is less than the second, thereby skipping unnecessary error correction stages and reducing latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional LDPC error correction performs multiple hard decoding operations with different read voltage thresholds, then error correction reliability is improved, but error correction time is extended
Solution Approach 1:
The system performs preliminary hard decoding operations with initial read voltage thresholds before committing to time-consuming soft decoding operations. By evaluating syndrome weights after hard decoding, the system can determine early whether soft decoding is necessary, avoiding unnecessary time expenditure while maintaining reliability
Solution Approach 2:
The error correction process dynamically adapts its path based on syndrome weight evaluation. The system transitions from hard decoding to soft decoding only when necessary (when syndrome weight threshold is not met), creating a dynamic, conditional execution flow that optimizes the balance between reliability and time
2Reliability
If soft decoding operations are performed after hard decoding fails, then error correction capability is improved, but operational interference increases
Solution Approach 1:
The system performs preliminary evaluation of syndrome weights after hard decoding to determine whether soft decoding is actually needed. This preliminary check prevents unnecessary soft decoding operations that would cause operational interference, while still maintaining the capability to perform soft decoding when truly necessary for error correction
3Device complexity
If read voltage thresholds are not optimized, then error correction process is simpler, but correction accuracy decreases
Solution Approach 1:
The system performs preliminary hard decoding operations with initial read voltage thresholds to evaluate syndrome weights. This preliminary action provides information about the quality of the initial decoding, allowing the system to determine whether more accurate soft decoding with optimized voltage thresholds is necessary
Solution Approach 2:
The system changes read voltage threshold parameters conditionally based on syndrome weight evaluation. When the syndrome weight indicates insufficient correction quality, the system proceeds to soft decoding with optimized voltage thresholds, thereby adapting parameters to maintain accuracy while avoiding unnecessary complexity
Data Source
AI summary
A storage device syndrome-weight-based error correction system includes a syndrome-weight-based error correction subsystem that is coupled to a storage subsystem in a chassis. The syndrome-weight-based error correction subsystem performs a first error correction hard decoding operation on the storage subsystem that utilizes first read voltage thresholds and that generates a first final codeword candidate having a first syndrome weight. The syndrome-weight-based error correction subsystem then performs error correction hard decoding read voltage threshold real-time search operations to determine second read voltage thresholds, and performs a second error correction hard decoding operation on the storage subsystem that utilizes the second read voltage thresholds and that generates a second final codeword candidate having a second syndrome weight. If the syndrome-weight-based error correction subsystem determines that the first syndrome weight is less than the second syndrome weight, it performs error correction soft decoding operations using the first read voltage thresholds.