On using the cyclically-coupled QC-LDPC codes in future SSDs

Abstract

As the flash memory continues its capacity scaling and correspondingly decreases its reliability, a technology upgrade regarding the error-correction engine in state-of-art solid-state drives (SSDs) is intensely expected. Due to their limit-approaching decoding ability, low-density parity-check (LDPC) codes are seen as one of the most promising substitute for the traditional BCH codes, though implementation barriers remain to degrade their performance. In our recent work, a co-design of LDPC block codes and their decoder architecture are developed and found suitable to apply to address these barriers with an overall excellence in error rate, complexity as well as throughput. Four codes of 4 KB and 4/5 rate are proposed and their FPGA-based implementations are conducted. It is shown that the decoders reach 1.47 Gb/s throughput at 100 MHz clock rates, and their complexity are estimated to be 1 million gates with 1 Mb memory.