Work-in-Progress: ECC Management with Rate Compatible LDPC Code for NAND Flash Storage

The NAND flash memory has rapidly increased in storage capacity per unit area, and the rate of occurrence of errors per P/E cycle is also rapidly increasing accordingly. ECC modules such as LDPC have been added to flash controller for recovering from the errors. However, the system designs to increase the lifetime of the flash memory storage device are still in great demand. In this paper, we design the LDPC encoding and decoding scheme to get stepwise code rate according to the P/E cycle by applying rate-compatible LDPC, as well as the management scheme of excessive parity data. Through this, we can improve the error recovery rate of flash memory storage system and extend the lifetime of NAND flash storage system while reducing the system read and write overhead due to the increase in additional parity data.