Abstract: Methods and apparatus are provided for soft data generation for memory devices using reference cells. At least one soft data value is generated in a memory device by writing a known data to one or more reference cells; reading one or more of the reference cells; obtaining a read statistic based on the read one or more reference cells; and obtaining the at least one soft data value based on the obtained read statistic. The read statistics can optionally be obtained for one or more desired locations of a memory array; or for a given pattern, PATT, in one or more aggressor cells. The read statistic can optionally comprise asymmetric statistics obtained for a plurality of possible values.

Abstract: A method and system for decoding information read from a non-volatile memory uses a two stage decoding algorithm, where the first stage is a high-speed, low precision decoder and the second stage is a low-speed, high precision decoder. Most of the time only the first stage of the decoder is used, which lowers the average power consumption of the decoding process.

Abstract: Methods and apparatus are provided for storing data in a multi-level cell flash memory device with cross-page sectors, multi-page coding and per-page coding. A single sector can be stored across a plurality of pages in the flash memory device. Per-page control is provided of the number of sectors in each page, as well as the code and/or code rate used for encoding and decoding a given page, and the decoder or decoding algorithm used for decoding a given page. Multi-page and wordline level access schemes are also provided.

Abstract: Methods and apparatus are provided for storing data in a multi-level cell flash memory device with cross-page sectors, multi-page coding and per-page coding. A single sector can be stored across a plurality of pages in the flash memory device. Per-page control is provided of the number of sectors in each page, as well as the code and/or code rate used for encoding and decoding a given page, and the decoder or decoding algorithm used for decoding a given page. Multi-page and wordline level access schemes are also provided.

Abstract: Methods and apparatus are provided for storing data in a multi-level cell flash memory device with cross-page sectors, multi-page coding and per-page coding. A single sector can be stored across a plurality of pages in the flash memory device. Per-page control is provided of the number of sectors in each page, as well as the code and/or code rate used for encoding and decoding a given page, and the decoder or decoding algorithm used for decoding a given page. Multi-page and wordline level access schemes are also provided.

Abstract: Methods and apparatus for soft data generation for memory devices using decoder performance feedback. At least one soft data value is generated in a memory device, by obtaining performance feedback from a decoder; obtaining an error statistic based on the performance feedback; and generating the at least one soft data value based on the obtained error statistic. The performance feedback comprises one or more of decoded bits, a number of erroneous bits based on data decoded by the decoder and a number of unsatisfied parity checks.

Abstract: Methods and apparatus are provided for soft data generation for memory devices. At least one soft data value is generated for a memory device, by obtaining at least one hard read value; and generating the soft data value associated with the at least one hard read value based on statistics for reading the hard read value. The hard read value may be one or more of data bits, voltage levels, current levels and resistance levels. The generated soft data value may be one or more of (i) a soft read value that is used to generate one or more log likelihood ratios, and (ii) one or more log likelihood ratios. The statistics comprise one or more of bit-based statistics and cell-based statistics. The statistics may also optionally comprise pattern-dependent disturbance of at least one aggressor cell on the target cell, as well as location-specific statistics.

Abstract: Methods and apparatus are provided for intercell interference mitigation using modulation coding. During programming of a flash memory, a modulation encoding is performed that selects one or more levels for programming the flash memory such that a reduced number of cells in the flash memory are programmed with a value that violates one or more predefined criteria. During a reading of a flash memory, a modulation decoding is performed that assigns one or more levels to cells in the flash memory such that a reduced number of cells in the flash memory are read with a value that violates one or more predefined criteria. The predefined criteria can be based, for example, on one or more of an amount of disturbance caused by the programmed cell; a voltage shift of a programmed cell: a voltage stored by a programmed cell; an amount of change in current through a programmed cell; and an amount of current through a programmed cell.

Abstract: Methods and apparatus are provided for soft demapping and intercell interference mitigation in flash memories. In one variation, a target cell in a flash memory device capable of storing at least two data levels, s, per cell is read by obtaining a measured read value, r, for at least one target cell in the flash memory; obtaining a value, h, representing data stored for at least one aggressor cell in the flash memory; selecting one or more probability density functions based on a pattern of values stored in at least a portion of the flash memory, wherein the probability density functions comprises pattern-dependent disturbance of one or more aggressor cells on the at least one target cell in the flash memory; evaluating at least one selected probability density function based on the measured read value, r; and computing one or more log likelihood ratios based on a result of the evaluating step.

Abstract: Methods and apparatus are provided for computing soft data or log likelihood ratios for received values in communication or storage systems. Soft data values or log likelihood ratios are computed for received values in a communication system or a memory device by obtaining at least one received value; identifying a segment of a function corresponding to the received value, wherein the function is defined over a plurality of segments, wherein each of the segments has an associated set of parameters; and calculating the soft data value or log likelihood ratio using the set of parameters associated with the identified segment. The computed soft data values or log likelihood ratios are optionally provided to a decoder.

Abstract: Methods and apparatus are provided for storing data in a multi-level cell flash memory device with cross-page sectors, multi-page coding and per-page coding. A single sector can be stored across a plurality of pages in the flash memory device. Per-page control is provided of the number of sectors in each page, as well the code and/or code rate used for encoding and decoding a given page, and the decoder or decoding algorithm used for decoding a given page. Multi-page and wordline level access schemes are also provided.

Abstract: Methods and apparatus are provided for storing data in a multi-level cell flash memory device with cross-page sectors, multi-page coding and per-page coding. A single sector can be stored across a plurality of pages in the flash memory device. Per-page control is provided of the number of sectors in each page, as well as the code and/or code rate used for encoding and decoding a given page, and the decoder or decoding algorithm used for decoding a given page. Multi-page and wordline level access schemes are also provided.

Abstract: Methods and apparatus are provided for storing data in a multi-level cell flash memory device with cross-page sectors, multi-page coding and per-page coding. A single sector can be stored across a plurality of pages in the flash memory device. Per-page control is provided of the number of sectors in each page, as well as the code and/or code rate used for encoding and decoding a given page, and the decoder or decoding algorithm used for decoding a given page. Multi-page and wordline level access schemes are also provided.

Abstract: Methods and apparatus are provided for storing data in a multi-level cell flash memory device with cross-page sectors, multi-page coding and per-page coding. A single sector can be stored across a plurality of pages in the flash memory device. Per-page control is provided of the number of sectors in each page, as well as the code and/or code rate used for encoding and decoding a given page, and the decoder or decoding algorithm used for decoding a given page. Multi-page and wordline level access schemes are also provided.

Abstract: Methods and apparatus are provided for programming multiple program values per signal level in flash memories. A flash memory device having a plurality of program values is programmed by programming the flash memory device for a given signal level, wherein the programming step comprises a programming phase and a plurality of verify phases. In another variation, a flash memory device having a plurality of program values is programmed, and the programming step comprises a programming phase and a plurality of verify phases, wherein at least one signal level comprises a plurality of the program values. The signal levels or the program values (or both) can be represented using one or more of a voltage, a current and a resistance.

Abstract: Methods and apparatus are provided for write-side intercell interference mitigation in flash memories. A flash memory device is written by obtaining program data to be written to at least one target cell in the flash memory; obtaining one or more bits of program data for at least one aggressor cell to be programmed later than the target cell: and precompensating for intercell interference for the target cell by generating precompensated program values. The aggressor cells comprise one or more cells adjacent to the target cell, such as adjacent cells in a same wordline as the target cell and/or cells in an upper or lower adjacent wordline to the target cell. The precompensated program values for the target cell are optionally provided to the flash memory.

Abstract: Methods and apparatus are provided for approximating a probability density function or distribution for a received value in communication or storage systems. A target distribution is approximated for a received value in one or more of a communication system and a memory device, by substantially minimizing a squared error between the target distribution of the received values and a second distribution obtained by mapping a predefined distribution, such as a Gaussian distribution, through a mapping function, wherein the second distribution has an associated set of parameters. The mapping function can be, for example, a piecewise linear function. The second distribution has a plurality of segments and each of the segments has an associated set of parameters. The associated set of parameters can be used to compute probability values, soft data values or log likelihood ratios.

Abstract: Methods and apparatus are provided for read-side intercell interference mitigation in flash memories. A flash memory device is read by obtaining a read value for at least one target cell; obtaining a value representing a voltage stored in at least one aggressor cell that was programmed after the target cell; determining intercell interference for the target cell from the at least one aggressor cell; and obtaining a new read value that compensates for the intercell interference by removing the determined intercell interference from the read value for the at least one target cell. The new read value can optionally be provided to a decoder. In an iterative implementation, one or more intercell interference mitigation parameters can be adjusted if a decoding error occurs.

Abstract: One or more methods and systems of effectively retrieving data stored in a media of a storage device are presented. The one or more methods and systems are implemented by way of correcting and detecting errors using a multi-stage decoding process. In one embodiment, the storage device comprises a magnetic hard drive. In one embodiment, the system and method applies an encoding/decoding technique that allows error correction and detection to be performed over a number of successive decode stages or processing stages. Use of the system and method increases the maximum number of symbol errors that may be corrected in an encoded codeword, providing an improvement in data recovery.

Abstract: Methods and apparatus are provided for computing a probability value of a received value in communication or storage systems. A probability value for a received value in a communication system or a memory device is computed by obtaining at least one received value; identifying a segment of a function corresponding to the received value, wherein the function is defined over a plurality of segments, wherein each of the segments has an associated set of parameters; and calculating the probability value using the set of parameters associated with the identified segment.