LDPC Soft Decoding with Reduced Power and Latency in 1X-2X NAND Flash-Based Solid State Drives

The reliability of the non-volatile NAND flash memories, measured in terms of Raw Bit Error Rate (RBER), is reaching critical levels for traditional error detection and correction. Therefore, to ensure data trustworthiness in nowadays NAND flash-based Solid State Drives, it becomes essential exploiting powerful correction algorithms such as the Low Density Parity Check (LDPC). However, the burdens of this approach materialize in an increased NAND flash power consumption due to the increased memory read latencies that translates in limited disk performance. In this work it is performed a comparison between a standard LDPC decoding approach based on hard and soft decisions and an optimized solution called LDPC NAND- Assisted Soft Decision. The simulation results on 2X, 1X and mid-1X MLC NAND flash-based Solid State Drives in terms of NAND flash I/O power consumption, disk read latencies and performance, favor the adoption of the presented solution.