LIAD: A Method for Extending the Effective Time of 3-D TLC NAND Flash Hard Decision

Triple-level cell NAND flash memory is widely used today due to its higher storage density and capacity. However, with the increase in the storage density, lower reliability results in more read times for flash memory and significantly reduces the read performance. In order to avoid unnecessary read operations, this article proposes a hard decision–soft decoding method called location information-assisted decoding (LIAD) method, which determines the additional information required for decoding by mutual information, and then transmits the required information to correct the log-likelihood ratio (LLR). Different from the conventional LLR correction algorithm, this method does not require additional read operations and correct data. Only using sensing results, our method can reduce uncorrectable error bit rate (UBER) by up to 99%, and the system read latency under SSDsim (Hu et al. 2011) simulation can be reduced by up to 53%.