Systems and methods for error correction and decoding on multi-level physical media

摘要

Apparatus and methods for operating a flash device characterized by use of Lee distance based codes in a flash device so as to increase the number of errors that can be corrected for a given number of redundancy cells, compared with Hamming distance based codes.

主权项

1. A method for operating a flash device, said method comprising:
reading, from flash memory cells the flash device, data symbols and redundancy symbols; calculating syndrome symbols based on the redundancy symbols; calculating estimated syndrome symbols based on at least the data symbols; calculating differences between the syndrome symbols and corresponding estimated syndrome symbols to provide error syndromes; and calculating corrected data symbols in response to the data symbols, the error syndromes; wherein the calculating of the corrected data symbols involves calculating Lee distances.