Data shaping to reduce error rates in solid state memory devices

A method implemented on a memory device, the method comprising:

• prior to applying a data shaping to input data:
• obtaining, for a group of cells on the memory device, information reflective of measured characteristics of the group of cells by performing write and read operations to the group of cells, wherein the measured characteristics vary among groups of cells on the memory device, the information identifying expected voltage ranges for at least two states in which individual cells within the group of cells may be placed;
• and
• identifying a state, of the at least two states, whose expected voltage range overlaps with the expected voltage range of another state of the at least two states, wherein the state is representative of a data value;
• obtaining the input data to be written to the group of cells;
• applying the data shaping to the input data to generate output data, wherein the data shaping is selected at least partly based on the identified state, and wherein the data shaping transforms the input data into the output data while reducing a probability of the data value occurring within the output data relative to a probability of the data value occurring within the input data;
• and
• storing the output data within the group of cells.

A memory device comprising:

• a non-volatile memory;
• and
• a controller comprising a processor and configured to:
• prior to applying a data shaping to input data:
• obtain, for a group of cells of the non-volatile memory, information reflective of measured characteristics of the group of cells by performing write and read operations to the group of cells, wherein the measured characteristics vary among groups of cells on the memory, the information identifying expected voltage ranges for at least two states in which the group of cells may be placed;
• and
• identify a state, of the at least two states, whose expected voltage range overlaps with the expected voltage range of another state of the at least two states, wherein the state is representative of a data value;
• obtain the input data to be written to the group of cells;
• apply the data shaping to the input data to generate output data, wherein the data shaping is selected at least partly based on the identified state, and wherein the data shaping transforms the input data into the output data while reducing a probability of the data value occurring within the output data relative to a probability of the data value occurring within the input data;
• and
• store the output data within the group of cells.

A memory device, comprising:

• means for storing a plurality of blocks of data;
• and
• controller means coupled to the means for storing, wherein the controller means is configured to:
• receive input data;
• prior to determining a data shaping to be applied to the input data:
• obtain, for a first block of the plurality of blocks, information reflective of measured characteristics of the first block by performing write and read operations to the first block, wherein the measured characteristics vary among the plurality of blocks, the information identifying an expected voltage range for each state of a plurality of states in which non-volatile solid-state memory cells of the first block are placed;
• and
• identify a state, of the plurality of states, whose expected voltage range overlaps with the expected voltage range of another state of the plurality of states, wherein the state is representative of a data value;
• determine, based at least partly on the state, the data shaping to be applied to the input data intended to be written to the first block, wherein the data shaping transforms the input data into output data while reducing a probability of the data value occurring within the output data relative to a probability of the data value occurring within the input data;
• apply the data shaping to the input data to transform the input data into the output data;
• and
• write the output data to the block, wherein the input data, if written to the first block, results in the non-volatile solid-state memory cells of the first block being placed in a uniform distribution of the plurality of states, and wherein the output data, when written to the block, results in the non-volatile solid-state memory cells of the first block being placed in a non-uniform distribution of the plurality of states.