Adaptive LDPC Decoder Parameters for 3D Flash Memory Zones
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Solution Overview
Problem
High-capacity data storage devices, such as 3D flash memory and multi-level cell (MLC) devices, are prone to errors due to dense threshold voltage distributions and cell-to-cell interference, which existing error correction codes struggle to address effectively, especially as operating conditions and physical locations within the memory device change.
Innovation Solution
The implementation of a self-adaptive low-density parity check (LDPC) decoder that adjusts its parameters based on operating conditions and physical locations within the memory device, using prior successful decoder parameters and a set of predefined parameters to optimize decoding performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional error correction codes are used for high-capacity data storage devices, then data storage capacity is increased, but error correction capability deteriorates due to dense threshold voltage distributions and cell-to-cell interference
Solution Approach 1:
The patent dynamically changes decoder parameters (such as threshold values, iteration counts, and syndrome calculation parameters) based on detected error patterns and operating conditions. This allows the LDPC decoder to adapt to varying error characteristics caused by dense threshold voltage distributions and cell-to-cell interference, maintaining high error correction capability while supporting high storage capacity
Solution Approach 2:
The patent implements a dynamic parameter adjustment mechanism where decoder parameters are not fixed but are continuously adapted based on real-time feedback from decoding performance and error patterns. This dynamic adaptation enables the system to handle the increased error rates associated with high-capacity storage while maintaining efficient decoding operation
2Reliability
If decoder parameters are optimized for each physical location zone, then decoding reliability is improved, but device complexity increases due to need for multiple parameter sets
Solution Approach 1:
The patent divides the memory device into multiple physical location zones (e.g., upper, middle, lower zones) and assigns different decoder parameter sets to each zone based on their specific error characteristics. This localized parameter optimization improves decoding reliability for each zone while managing complexity through systematic zone-based classification rather than individual parameter optimization for each memory cell
Solution Approach 2:
The patent segments the memory device into distinct physical location zones and creates separate parameter optimization strategies for each segment. This segmentation approach reduces overall system complexity by grouping memory locations with similar error characteristics together, allowing for manageable parameter sets rather than requiring unique parameters for every memory cell
3Reliability
If large look-up tables are used to store optimal decoder parameters, then decoding performance is improved, but memory resource consumption increases
Solution Approach 1:
Instead of storing large look-up tables with pre-computed optimal parameters for all possible conditions, the patent implements a dynamic parameter generation mechanism that computes appropriate decoder parameters on-demand based on current error patterns and operating conditions. This approach maintains high decoding performance while significantly reducing memory resource consumption by eliminating the need for extensive pre-stored parameter tables
Data Source
AI summary
Disclosed are methods, systems and devices for decoding data read from a memory device, including receiving noisy data from a first memory location included in a word line zone of the memory device, identifying the word line zone and a prior successful decoder parameter associated with the word line zone, decoding the noisy data using the prior successful decoder parameter used in a prior successful decoding with respect to a second memory location included in the same word line zone, determining whether the decoding based on the prior successful decoder parameter has succeeded, maintaining, upon a determination that the decoding has succeeded, the prior successful decoder parameter as a decoder parameter for the first memory location, and decoding, upon a determination that the decoding operation has failed, the noisy data read from the first memory location by using another decoder parameter selected from a set of predefined decoder parameters.