Single-Read Soft Decoding for Solid-State Memory Recovery
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Solution Overview
Problem
In solid-state memory systems, error correction after a first read can fail, leading to additional reads from the memory array, which increases read time and negatively affects system performance and throughput, especially as the memory ages.
Innovation Solution
A one-read soft-decision decoding scheme is implemented, utilizing existing data from a first read to provide reliability information for failed code words, allowing recovery without additional reads, thereby improving system performance and postponing performance degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional reads are performed to recover uncorrectable code words, then data reliability is improved, but read time increases and system throughput deteriorates
Solution Approach 1:
The patent performs preliminary actions during the first read operation by capturing and storing reliability information (such as read voltages, pass/fail status, and error patterns) before the decode failure occurs. This preliminary data collection enables subsequent soft decoding attempts without requiring additional physical reads from the memory array, thus resolving the contradiction between data recovery capability and system throughput
2Reliability
If additional reads are performed after decode failure, then uncorrectable errors can be recovered, but read time increases
Solution Approach 1:
The patent creates a copy of the reliability information from the first read operation and uses this copied data for multiple soft decoding attempts. Instead of performing additional physical reads, the system repeatedly processes the copied reliability data through different decoding algorithms and parameters, enabling comprehensive error recovery without incurring additional read time penalties
3Productivity
If hard decoding is used with single read, then system throughput is maintained, but uncorrectable errors cannot be recovered
Solution Approach 1:
The patent changes the decoding parameters by implementing soft decoding that utilizes reliability information (such as log-likelihood ratios, read voltage levels, and error patterns) captured during the first read. This parameter change enables the decoder to make more informed decisions about error correction, significantly improving data recovery capability while maintaining single-read operation and thus preserving system throughput
Data Source
AI summary
Systems and methods are disclosed for decoding solid-state memory cells using one-read soft decision decoding. A controller of a data storage device is configured to perform a first decoding of a first code word based at least in part on data associated with a reading of the first code word, and to detect a decoding failure associated with the first decoding. The controller determines reliability information for decoding the first code word in response to the decoding failure based at least in part on data associated with a successful decoding of a second code word and performs a second decoding of the first code word based at least in part on the reliability information.