Interference-aware assignment of programming levels in analog memory cells

摘要

A method for data storage includes accepting data for storage in a memory including multiple analog memory cells. For each memory cell, a respective set of nominal analog values is assigned for representing data values to be stored in the memory cell, by choosing the nominal analog values for a given memory cell in a respective range that depends on interference between the given memory cell and at least one other memory cell in the memory. The data is stored in each memory cell using the respective selected set of the nominal analog values.

主权项

1. A method for data storage, comprising:
accepting data for storage in a memory comprising multiple memory cells; assigning, for each memory cell, a respective set of nominal analog values for representing data values to be stored in the memory cell, by choosing the nominal analog values for a given memory cell in a respective range that depends on interference between the given memory cell and at least one other memory cell in the memory; encoding the data with a shaping code that causes the encoded data to be mapped to the nominal analog values chosen within the respective range in each memory cell; and storing the encoded data in each memory cell using the respective selected set of the nominal analog values; dividing, for a group of N memory cells, an N-dimensional space that includes a number of combinations of respective analog values of the N memory cells into a first region that includes combinations of nominal analog values that are unavailable for assignment due to the interference, and a second region includes combinations of nominal analog values that are available for assignment; and assigning the sets of the nominal analog values to the N memory cells only within the second region.