Quasi-Cyclic LDPC Padding for SSD Space-Aligned Error Correction
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Solution Overview
Problem
The existing quasi-cyclic LDPC codes in SSDs face challenges in adapting to the internal space of flash memory, leading to degraded error correction capabilities and reduced reliability and service life due to the need to modify code lengths by deleting or adding check bits, which affects the storage unit's internal space alignment.
Innovation Solution
A data processing method and system that calculates the magnitude of the information bit of the quasi-cyclic LDPC, fills service data to match the storage unit's size, and codes it to generate redundancy check data, ensuring the code length adapts to the storage unit's space while maintaining high error correction capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the code length of quasi-cyclic LDPC is changed by deleting or adding check bits to adapt to flash memory internal space, then the adaptation to storage unit space is improved, but the error correction capability is degraded
Solution Approach 1:
The patent changes the code length parameter of quasi-cyclic LDPC by deleting or adding check bits to make the code length an integral multiple of the circulant matrix magnitude (128 bits), enabling ideal adaptation to flash memory internal space. This parameter change resolves the space alignment issue while maintaining the quasi-cyclic structure for efficient encoding and decoding.
Solution Approach 2:
The patent dynamically adjusts the code length of LDPC codes based on the specific storage capacity of flash memory devices. By making the code length adaptable rather than fixed, the system can optimize the balance between space utilization and error correction performance for different device configurations.
2Reliability
If the code length of quasi-cyclic LDPC is kept constant, then the error correction capability is maintained, but the adaptation to storage unit internal space is degraded
Solution Approach 1:
The patent introduces a configurable code length parameter that can be adjusted based on storage unit capacity. The code length is set to an integral multiple of the circulant matrix magnitude, allowing the system to maintain optimal error correction capability while adapting to different flash memory sizes through parameter configuration rather than structural changes.
3Adaptability or versatility
If puncturing operation is performed on check bits to adjust code length, then the space adaptation is improved, but the original check bits are changed causing error floor phenomenon
Solution Approach 1:
The patent segments the LDPC code structure into information bits and check bits, where check bits are specifically designed to be deletable without affecting the core error correction capability. By segmenting the code in this way, the system can remove redundant check bits for space adaptation while preserving the essential error correction functionality through the remaining structured check bits.
Solution Approach 2:
Instead of performing puncturing operations that alter original check bits, the patent changes the code length parameter by selectively adding or removing check bits in a controlled manner. This parameter change approach maintains the integrity of the error correction mechanism while achieving the desired code length for space adaptation.
Data Source
AI summary
A data processing method based on a quasi-cyclic LDPC includes: when a size of service data is less than a magnitude of information bit of the quasi-cyclic LDPC, calculating a difference value between the magnitude of the information bit of the quasi-cyclic LDPC and the size of the service data, and filling the service data with the same amount of known data as the difference value (S103); coding the filled service data to obtain redundancy check data corresponding to the service data (S104); and sending the service data and the redundancy check data to a corresponding physical location in the storage unit (S105). It ensures that when a code length of the quasi-cyclic LDPC is constant, the code length ideally adapts to internal space of the storage unit, and the quasi-cyclic LDPC has a relatively high error correction capability, thereby improving reliability and service life of the storage unit.