Design and optimization of adaptable BCH codecs for NAND flash memories

NAND flash memories represent a key storage technology for solid-state storage systems. However, they suffer from serious reliability and endurance issues that must be mitigated by the use of proper error correction codes. This paper proposes the design and implementation of an optimized Bose–Chaudhuri–Hocquenghem hardware codec core able to adapt its correction capability in a range of predefined values. Code adaptability makes it possible to efficiently trade-off, in-field reliability and code complexity. This feature is very important considering that the reliability of a NAND flash memory continuously decreases over time, meaning that the required correction capability is not fixed during the life of the device. Experimental results show that the proposed architecture enables to save resources when the device is in the early stages of its lifecycle, while introducing a limited overhead in terms of area.