An LDPC code decoding method based on threshold voltage drift perception

Abstract

The invention discloses an LDPC code decoding method based on threshold voltage drift perception, and the method comprises the steps of obtaining a current drift parameter of a flash memory page P towhich to-be-decoded data belongs, and obtaining the threshold voltage distribution D of a storage unit in the current flash memory page P according to the corresponding relation between the thresholdvoltage distribution of the storage unit and the drift parameter; taking the voltage at each tail end point of the standard read reference voltage and the threshold voltage distribution D as a sampling voltage, and determining the voltage range [vi, vj] where the threshold voltage of each storage unit is located by applying different sampling voltages; calculating soft decision information according to the voltage range [vi, vj], and performing LDPC code decoding on the to-be-decoded data according to the soft decision information, wherein the drift parameter comprises the erasing frequency and the data storage time, and v is smaller than vj. According to the invention, the soft decision information can be accurately acquired by utilizing the drift characteristic of the threshold voltage of the storage unit, so that the decoding performance of the LDPC code can be improved, and the decoding delay is reduced.

Description

technical field [0001] The invention belongs to the technical field of solid-state disk storage, and more particularly relates to an LDPC code decoding method with threshold voltage drift perception. Background technique [0002] Three-dimensional stacked flash memory has the characteristics of high storage density, so it is widely used as a storage device in solid-state disks, smart phones and computer systems. However, high storage density reduces data storage reliability. LDPC code (Low-Density Parity-Check, low-density parity-check code) has a strong error correction capability and is applied to three-dimensional stacked flash memory to ensure data storage reliability. LDPC is a soft-decision error correction code. Before decoding, it needs to use multiple levels to obtain soft-decision information. High-precision soft-decision information can improve decoding performance and reduce decoding delay. In three-dimensional stacked flash memory, in order to obtain high-prec...

AI Technical Summary

Problems solved by technology

In the three-dimensional stacked flash memory, this drift phenomenon is very significant, but the existing flash memory decoding method does not consider the drift characteristics of the threshold voltage of the memory cell in the three-dimensional stacked flash memory when obtaining the soft decision information, which makes the acquired soft decision information The accuracy of decision information is not high, resulting in low decoding performance and high decoding delay, which in turn increases the read overhead of 3D stacked flash memory

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