Feature based read threshold estimation in nand flash memory

Abstract

A method for reading data from a solid-state drive (SSD) configured to store data in a plurality of memory cells arranged in memory blocks comprising rows, the method performed by a controller in communication with the plurality of memory cells. The method comprises retrieving data from a target row of memory cells of the plurality of memory cells associated with a read request received from a host using initial threshold voltages. The method also includes decoding the data using a hard decision stage. Additionally the method comprises estimating read threshold voltages of the target row of memory cells based on a transformation of a distribution of threshold voltages of cells in a memory block containing the target row when the hard decision decoding stage fails. The method further includes retrieving data from the target row using the estimated read threshold voltages.