基于多精度感知的MLC闪存比特翻转译码算法

Bit-flipping Decoding Algorithm for MLC Flash Memory Based on Multiple Precision Sensing Strategy

随着多级单元(multi-level cell,MLC)闪存存储密度的增加,单元间干扰(cell-to-cell interference,CCI)成为影响NAND闪存可靠性的主要噪声;在深入研究MLC闪存模型和CCI噪声模型基础上,提出了一种MLC闪存多精度感知的比特翻转译码方法,该方法通过选取合适的MLC闪存单元感知精度进而得到MLC单元中存储比特的准确对数似然比信息,利用此信息可降低原始错误比特率并且提高比特翻转译码算法的译码性能;仿真结果表明,在MLC闪存信道条件下,所给方法提高了比特翻转译码算法译码性能,并且保持较低的译码复杂度和较短的感知时延。

With the increase of MLC （Multi-Level Cell） flash memory density, CCI （Cell-to-Cell Interference） is the dominant noise source which affects the reliability of NAND flash memory. On the research of MLC flash memory model and CCI noise model, bit-flipping decoding algorithm based on multiple precision sensing is proposed for MLC flash memory. This method can obtain accurate LLR （ Log-Likelihood Ratio） information of bit stored in MLC by selecting the appropriate sensing precision of MLC flash memory, thus the accurate LLR information helps reduce the REBR （Raw Error Bit Rate） and improve the decoding performance of bit-flipping decoding algorithm. The simulation results show that the proposed method improves the decoding performance of bit-flipping decoding algorithm, and maintains a lower decoding complexity and a shorter sensing delay.