Coded modulation for digital storage in analog memory devices

An analog memory device for storing a plurality of information bits, comprising:

• a plurality of analog memory cells;
• a coder having an input connected to receive the information bits, the coder coding at least a portion of a given set of b of the information bits to generate a corresponding set of coded bits including more than b bits, such that the portion of the information bits subject to the coding is transformed into corresponding coded bits in the set of coded bits;
• and
• a mapper having an input coupled to an output of the coder and receiving the set of coded bits, wherein the mapper is operative to map the set of coded bits to one or more corresponding levels, such that each of the one or more levels can be stored in one of the plurality of analog memory cells;
• wherein the mapper is configured to provide at least one of:
• (i) an increase in an effective storage capacity of at least a subset of the analog memory cells;
• and (ii) a decrease in a readout error probability of at least a subset of the analog memory cells;
• relative to an effective storage capacity and a readout error probability associated with storage of unmapped analog levels in the analog memory cells.

A method of storing information bits in an analog memory device, the device including a plurality of analog memory cells, the method comprising the steps of:

• coding at least a portion of a given set of b of the information bits to generate a corresponding set of coded bits including more than b bits, such that the portion of the information bits subject to the coding is transformed into corresponding coded bits in the set of coded bits;
• mapping a given set of the coded bits to one or more levels;
• storing each of the one or more levels in one of the cells of the analog memory device;
• and
• generating a single readout value using results of multiple readouts of a stored level from a given one of the cells
• wherein the mapping step is configured to provide at least one of:
• (i) an increase in an effective storage capacity of at least a subset of the analog memory cells;
• and (ii) a decrease in a readout error probability of at least a subset of the analog memory cells;
• relative to an effective storage capacity and a readout error probability associated with storage of unmapped analog levels in the analog memory cells.

An analog memory device for storing a plurality of information bits, comprising:

• a plurality of analog memory cells;
• a coder operative to code at least a portion of a given set of b of the information bits to generate a corresponding set of coded bits including more than b bits, such that the portion of the information bits subject to the coding is transformed into corresponding coded bits in the set of coded bits;
• a mapper operative to map a set of the coded bits to one or more levels, such that each of the one or more levels is stored in one of the plurality of cells;
• and
• a readout unit having an input coupled to an output of a given one of the memory cells, wherein the readout unit is operative to generate a single readout value using results of multiple readouts of a stored level from the given cell;
• wherein the mapper is configured to provide at least one of:
• (i) an increase in an effective storage capacity of at least a subset of the analog memory cells;
• and (ii) a decrease in a readout error probability of at least a subset of the analog memory cells;
• relative to an effective storage capacity and a readout error probability associated with storage of unmapped analog levels in the analog memory cells.