An optimization method of ldpc decoding based on flash programming disturbance error perception

Abstract

The invention discloses an LDPC (low density parity check) decoding optimization method based on flash programming interference error perception. Along with the increase of NAND flash-memory storage density, more bit information is stored in each unit; the coupling interference along the units is high; the serious programming interference errors are caused, so that the traditional BCH code cannot ensure the data reliability; the LDPC code has error-correcting performance superior to that of the BCH code, and is applied to an NAND flash-memory storage system. The used optimized LDPC decoding algorithm has important significance. Through observation, the programming interference errors have value correlative characters; when the LDPC decoding is performed, the value correlative characters of the programming interference errors can be blended into the LDPC decoding process; the additional information is provided for bit judgment, so that the bit judgment precision is improved; the decoding convergence speed is accelerated; the LDPC decoding delay is reduced.

Description

technical field [0001] The invention belongs to the technical field of solid-state disk storage, and more specifically relates to an LDPC decoding optimization method based on flash programming interference error perception. Background technique [0002] Solid State Disk (SSD for short) based on NAND flash memory has the advantages of high performance, large capacity, anti-vibration, low power consumption and non-volatility, and is widely used in computer storage systems. Solid state disk SSD uses NAND flash memory (NAND flash) as the storage medium. With the improvement of NAND flash manufacturing process, each unit stores more bit information. For example, each unit of MLC NAND flash memory stores two bits of information, and the unit stores less information. The charge and the distance between the cells are relatively close, and the coupling interference between the cells is relatively strong. When a programming operation is performed on a certain page in the NAND flash m...

AI Technical Summary

Problems solved by technology

[0005] The existing LDPC decoding algorithm has the following obvious deficiencies: 1. The existing LDPC decoding algorithm only considers the internal information transmission and does not make full use of the error mode characteristics of the flash itself, which has high decoding complexity and larger decoding delay overhead; 2. The existing LDPC decoding algorithm does not consider the influence of the numerical correlation feature of the program disturbance error, and does not incorporate this favorable feature into the LDPC decoding information update process; 3. The existing The LDPC decoding algorithm does not provide additional decision information, and simply relies on the characteristics of the decoding mechanism itself to update information

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