High quality log likelihood ratios determined using two-index look-up table

Abstract

A nonvolatile memory controller includes memory storage configured to store a two-index look-up table that includes a Log-Likelihood Ratio (LLR), hard-and-soft-decision bits associate with the LLR and a neighboring cell read pattern associated with the LLR. Read circuitry is configured to perform a plurality of reads of a cell of a nonvolatile memory storage module at different read voltage levels to generate target cell hard-and-soft-decision bits and configured to read neighboring cells to generate neighboring cell reads. Neighboring cell processing circuitry combines the neighboring cell reads to generate a neighboring cell read pattern. Look-up circuitry accesses the two-index look-up table using the target cell hard-and-soft-decision bits and the neighboring cell read pattern to identify the corresponding LLR for use in Low-Density Parity Check (LDPC) decoding of a codeword stored in the nonvolatile memory storage module.