WOM Codes Against Inter-Cell Interference in NAND Memories
Flash memories, especially NAND flash memories, are prevalent in the memory market due to their outstanding features such as high density and so on. However, the problems coming with the density are the parasitic effects, of which the cell-to-cell interference is the dominant one. Besides interference, another challenge for NAND flash memories is its limited life time. Actually, flash memories can be regarded as "Write-Once Memories (WOM)", where cells can be changed from lower states to higher states, not vice versa. In this paper, the authors study WOM codes against cell-to-cell interference. They derive bounds of the rewriting capacity of WOM codes based on the new WOM codes, Delta-WOM, and constrained codes.