Solid-State Storage State Detection for LDPC Decoding Accuracy
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Solution Overview
Problem
Existing error correction technologies, such as BCH coding, are insufficient in providing adequate correction capability for non-volatile memory as manufacturing technologies improve, leading to increased error probability and reduced reliability in solid state storage devices.
Innovation Solution
A method is introduced that applies multiple sensing voltages to non-volatile memory units to define storing states, calculating strong correct and error ratios, and generating log-likelihood ratios to improve data bit value decoding accuracy, thereby enhancing error correction capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If BCH coding technology is used for error correction, then fast computation is achieved, but correction capability becomes insufficient as manufacturing technologies improve
Solution Approach 1:
The patent transitions from BCH coding to LDPC coding, changing the fundamental error correction algorithm parameters. LDPC codes provide stronger correction capability for modern high-capacity non-volatile memories while maintaining computational efficiency through iterative decoding processes.
2Productivity
If non-volatile memory undergoes multiple erasing and writing operations, then storage capacity is utilized, but error probability increases and reliability decreases
Solution Approach 1:
The patent applies error correction coding (LDPC) in advance during the writing process and performs preliminary error detection and correction during reading operations. This preliminary action prevents error accumulation from multiple erase-write cycles, maintaining reliability even as storage capacity is fully utilized.
3Measurement precision
If sensing voltages are applied to define storing states, then data bit value decoding accuracy is improved, but device complexity increases
Solution Approach 1:
The patent segments the threshold voltage distribution into multiple regions (strong correct region, weak correct region, strong error region, weak error region) by applying multiple sensing voltages. This segmentation enables more precise decoding by treating different threshold voltage ranges differently, improving accuracy while managing complexity through systematic region classification.
Data Source
AI summary
A method for detecting storing states of a solid state storage device is provided, including steps of: applying sensing voltages to memory units; comparing threshold voltages of the memory units with the sensing voltages and accordingly to define the storing states including a strong correct region, a weak correct region, a strong error region and a weak error region, in which the memory units are classified; calculating the number of the memory units in the storing states; calculating a strong correct ratio of the number of the memory units in the strong correct region to the number of the memory units in the strong and weak correct regions; calculating a strong error ratio of the number of the memory units in the strong error region to the number of the memory units in the strong and weak error regions; and generating a log-likelihood ratio based on said ratios.