Patent application number | Description | Published |
20090185643 | Methods and Apparatus for Map Detection with Reduced Complexity - Methods and apparatus are provided for high-speed, low-power, high-performance channel detection. A soft output channel detector is provided that operates at a rate of 1/N and detects N bits per 1/N-rate clock cycle. The channel detector comprises a plurality, D, of MAP detectors operating in parallel, wherein each of the MAP detectors generates N/D log-likelihood ratio values per 1/N-rate clock cycle and wherein at least one of the plurality of MAP detectors constrains each of the bits. The log-likelihood ratio values can be merged to form an output sequence. A single MAP detector is also provided that comprises a forward detector for calculating forward state metrics; a backward detector for calculating backward state metrics; and a current branch detector for calculating a current branch metric, wherein at least two of the forward detector, the backward detector and the current branch detector employ different trellis structures. | 07-23-2009 |
20090187813 | Methods and Apparatus for Reduced Complexity Soft-Output Viterbi Detection - Methods and apparatus are provided for reduced complexity Soft-Output Viterbi detection. A Soft-Output Viterbi algorithm processes a signal by determining branch metrics using a branch metrics unit; determining survivor paths for sequence detection using a first add-compare select unit; and determining survivor paths for generating one or more bit reliability values using a second add-compare select unit, wherein the first and second add-compare select units process the branch metrics determined by the branch metrics unit. The first and second add-compare select units can optionally process branch metrics having a different number of bits. A sequence detector is provided that comprises a branch metrics unit for determining branch metrics having a first precision; a programmable precision conversion unit for converting the branch metrics having the first precision to branch metrics having a desired precision; and an add-compare select unit for computing path metrics based on the desired precision branch metrics. The Soft-Output Viterbi processor optionally processes a trellis having a reduced number of states relative to a trellis processed by the sequence detector. | 07-23-2009 |
20110090734 | METHODS AND APPARATUS FOR STORING DATA IN A MULTI-LEVEL CELL FLASH MEMORY DEVICE WITH CROSS-PAGE SECTORS, MULTI-PAGE CODING AND PER-PAGE CODING - 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. | 04-21-2011 |
20110216586 | Methods And Apparatus For Intercell Interference Mitigation Using Modulation Coding - 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. | 09-08-2011 |
20110225350 | Methods and Apparatus for Soft Data Generation for Memory Devices Based Using Reference Cells - 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. | 09-15-2011 |
20110243281 | PIPELINED DECISION-FEEDBACK UNIT IN A REDUCED-STATE VITERBI DETECTOR WITH LOCAL FEEDBACK - A pipelined decision feedback unit (DFU) is disclosed for use in reduced-state Viterbi detectors with local feedback. The disclosed pipelined decision feedback unit improves the maximum data rate that may be achieved by the reduced state Viterbi detector by the pipelined computation of partial intersymbol interference-based estimates. A pipelined decision feedback unit is thus disclosed that computes a plurality of partial intersymbol interference based estimates, wherein at least one partial intersymbol interference-based estimate is based on a selected partial intersymbol interference-based estimate; and selects the selected partial intersymbol interference-based estimate from among partial intersymbol interference-based estimates for path extensions into a state. | 10-06-2011 |
20110246136 | METHODS AND APPARATUS FOR COMPUTING A PROBABILITY VALUE OF A RECEIVED VALUE IN COMMUNICATION OR STORAGE SYSTEMS - 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. A probability value for a received value in a communication system or a memory device can also be computed by calculating the probability value for the received value using a first distribution, wherein the first distribution is predefined and wherein a mapped version of the first distribution approximates a distribution of the received values and wherein the calculating step is implemented by a processor, a controller, a read channel, a signal processing unit or a decoder. | 10-06-2011 |
20110246842 | METHODS AND APPARATUS FOR APPROXIMATING A PROBABILITY DENSITY FUNCTION OR DISTRIBUTION FOR A RECEIVED VALUE IN COMMUNICATION OR STORAGE SYSTEMS - 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. | 10-06-2011 |
20110246859 | METHODS AND APPARATUS FOR COMPUTING SOFT DATA OR LOG LIKELIHOOD RATIOS FOR RECEIVED VALUES IN COMMUNICATION OR STORAGE SYSTEMS - 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. | 10-06-2011 |
20110292535 | METHODS AND APPARATUS FOR SYNCHRONIZATION MARK DETECTION BASED ON A POSITION OF AN EXTREME DISTANCE METRIC - Methods and apparatus are provided for detection of a synchronization mark based on a position of an extreme distance metric. A synchronization mark is detected in a received signal by computing a distance metric between the received signal and an ideal version of the received signal expected when reading the synchronization mark, wherein the distance metric is computed for a plurality of positions within a search window; determining a substantially extreme distance metric within the search window; and detecting the synchronization mark based on a position of the substantially extreme distance metric. The distance metric can comprise a sum of square differences or a Euclidean distance between the received signal and the ideal version of the received signal. | 12-01-2011 |
20120063022 | Systems and Methods for Inter-track Interference Compensation - Various embodiments of the present invention provide systems and methods for data processing. As an example, a data processing circuit is discussed that includes: a data buffer, an inter-track interference response circuit, and an inter-track interference signal estimator circuit. The data buffer is operable to store a previous track data set. The inter-track interference response circuit is operable to estimate an inter-track interference response from the previous track data set based at least in part on the previous track data set and a current track data set. The inter-track interference signal estimator circuit is operable to calculate an inter-track interference from the previous track data set based at least in part on the previous track data set and the inter-track interference response from the previous track data set. | 03-15-2012 |
20120063023 | Systems and Methods for Block-wise Inter-track Interference Compensation - Various embodiments of the present invention provide systems and methods for data processing. As an example, a block-wise data processing circuit is discussed that includes: a data buffer, an inter-track interference response circuit, and an inter-track interference signal estimator circuit. The data buffer is operable to store a previous track data set corresponding to a block. The inter-track interference response circuit is operable to estimate an inter-track interference response from the previous track data set across the block based at least in part on the previous track data set and a current track data set. The inter-track interference signal estimator circuit is operable to calculate an inter-track interference from the previous track data set across the block based at least in part on the previous track data set and the inter-track interference response from the previous track data set. | 03-15-2012 |
20120063024 | Systems and Methods for Handling Sector Gaps in Inter-track Interference Compensation - Various embodiments of the present invention provide systems and methods for data processing. As an example, a data processing circuit is discussed that includes an inter-track interference determination circuit operable to calculate an inter-track interference from a previous track data set based at least in part on the previous track data set and a current track data set. The previous track data set includes a gap. A portion of the data in the previous track data set corresponds to a previous track on a storage medium, and the data in the previous track data set corresponding to the gap corresponds to a track preceding a previous track. | 03-15-2012 |
20120063284 | Systems and Methods for Track to Track Phase Alignment - Various embodiments of the present invention provide systems and methods for data processing. As an example, a data processing circuit is discussed that includes: a data buffer, an inter-track interference response circuit, an inter-track interference signal estimator circuit, and a sync mark detector circuit. The data buffer is operable to store a previous track data set that includes a first sync pattern. The inter-track interference response circuit is operable to estimate an inter-track interference response from the previous track data set based at least in part on the previous track data set and a current track data set. The current track data set includes a second sync pattern. The inter-track interference signal estimator circuit is operable to calculate an inter-track interference from the previous track data set based at least in part on the previous track data set and the inter-track interference response from the previous track data set. The sync mark detector circuit operable to identify the first sync pattern in the inter-track interference from the previous track data set in the current track data set. | 03-15-2012 |
20120170678 | METHODS AND APPARATUS FOR TRELLIS-BASED MODULATION ENCODING - Methods and apparatus are provided for trellis-based modulation encoding. A signal is modulation encoded by encoding one or more blocks of the signal using one or more corresponding edges in a trellis, wherein each edge in the trellis has a corresponding bit pattern; selecting a winning path through the trellis based on at least one transition-based run-length constraint; and generating an encoded sequence using edges associated with the winning path. Exemplary trellis pruning techniques are also provided. The winning path through the trellis is selected by minimizing one or more modulation metrics. | 07-05-2012 |
20120290894 | MEMORY READ-CHANNEL WITH SIGNAL PROCESSING ON GENERAL PURPOSE PROCESSOR - Methods and apparatus are provided for processing a data value in a read channel of a memory device. The data value provided to a general purpose processor for processing. The data value is not decoded data and may comprise one or more of a raw data value and an intermediate data value. The data value can be provided to the general purpose processor, for example, upon a detection of one or more predefined trigger conditions. A data value can be obtained from a memory device and then be redirected to a general purpose processor. The data value is not decoded data. The redirection can be conditionally performed if one or more predefined bypass conditions exist. The general purpose processor is optionally time-shared with one or more additional applications. | 11-15-2012 |
20130054663 | Determining Coefficients For Digital Low Pass Filter Given Cutoff And Boost Values For Corresponding Analog Version - Methods and apparatus are provided for determining coefficients for a digital low pass filter, given cutoff and boost values for a corresponding analog version of the digital low pass filter. Coefficients are determined for a digital low pass filter by obtaining cutoff and boost values for a corresponding analog version of the digital low pass filter; and determining the coefficients for the digital low pass filter based on the obtained cutoff and boost values. The coefficients can be determined, for example, by generating a transfer function, H(s), for the corresponding analog version using the obtained cutoff and boost values: transforming the transfer function, H(s), to a frequency domain characterization, H(z), using one or more bilinear transforms to obtain a plurality of coefficients for an infinite impulse response (IIR) filter; generating the IIR filter using the plurality of coefficients for the IIR filter; and applying an impulse to the IIR filter to obtain the one or more coefficients for the digital low pass filter. In another variation, the coefficients are pre-computed and obtained from a look-up table. | 02-28-2013 |
20130083417 | Hardware-Based Methods And Apparatus For Inter-Track Interference Mitigation In Magnetic Recording Systems - Hardware-based methods and apparatus are provided for inter-track interference mitigation in magnetic recording systems. Inter-track interference (ITI) is mitigated in a magnetic recording system by obtaining ITI cancellation data; and providing the ITI cancellation data to an ITI mitigation circuit using a write data path in the magnetic recording system. The write data path can optionally operate substantially simultaneously with the read data path performing the read operation. The ITI cancellation data comprises, for example, user data and/or media data. | 04-04-2013 |
20130083418 | HARDWARE-BASED INTER-TRACK INTERFERENCE MITIGATION IN MAGNETIC RECORDING SYSTEMS WITH READ CHANNEL STORAGE OF CANCELATION DATA - Hardware-based methods and apparatus are provided for inter-track interference mitigation in magnetic recording systems. Inter-track interference (ITI) cancellation data is stored in a memory of a read channel of a magnetic recording system. The memory can be in a write data path or a read data path of the read channel. The inter-track interference cancellation data is optionally provided to an inter-track interference mitigation circuit using at least a portion of a write data path, for example, based on a control signal. The storage of the inter-track interference cancellation data can be in response to a second control signal. | 04-04-2013 |
20130120867 | Methods and Apparatus for Map Detection with Reduced Complexity - Methods and apparatus are provided for high-speed, low-power, high-performance channel detection. A soft-output detector is provided for processing a received signal, comprising: a forward detector for calculating forward state metrics; a backward detector for calculating backward state metrics; and a current branch detector for calculating a current branch metric, wherein at least two of the forward detector, the backward detector and the current branch detector employ trellis structures with a different number of states. A method is provided for processing a received signal using a soft-output detector, comprising: calculating forward state metrics using a forward detector; calculating backward state metrics using a backward detector; and calculating a current branch metric using a current branch detector, wherein at least two of the forward detector, the backward detector and the current branch detector employ trellis structures with a different number of states. | 05-16-2013 |
20130145235 | DETECTION AND DECODING IN FLASH MEMORIES WITH SELECTIVE BINARY AND NON-BINARY DECODING - Methods and apparatus are provided for detection and decoding in flash memories with selective binary and non-binary decoding. Data from a flash memory device is processed by obtaining one or more read values for a plurality of bits from one or more pages of the flash memory device; converting; the one or more read values for the plurality of bits to a non-binary log likelihood ratio based on a probability that a given data pattern was written to the plurality of bits when a particular pattern was read from the plurality of bits; and jointly decoding the plurality of bits using the non-binary log likelihood ratio, wherein the pages are encoded independently. | 06-06-2013 |
20130145238 | ENCODING AND DECODING IN FLASH MEMORIES USING CONVOLUTIONAL-TYPE LOW PARITY DENSITY CHECK CODES - Methods and apparatus are provided for encoding and decoding in flash memories using convolutional-type low parity density check codes. A plurality of bits to be stored on a flash memory device are encoded using a convolutional-type low density parity check code, such as a spatially coupled low density parity check code. The encoded pages or portions thereof can be decoded independently of other pages. In one embodiment, an encoded page is decoded jointly with one or more additional pages in the same wordline or a different wordline. | 06-06-2013 |
20130148230 | Systems and Methods for Medium Proximity Detection in a Read Channel - A contact event between a sensing device and a storage medium is detected by receiving a signal indicating a physical proximity between the sensing device and the storage medium; generating a plurality of frequency bin outputs; comparing one or more frequency bin outputs to a corresponding first level threshold to yield a corresponding comparator output; summing the comparator output with at least one prior instance of the comparator output to yield an aggregated value; comparing the aggregated value to an aggregate threshold to yield an aggregate output; and generating a contact event output if one or more of a first group of the plurality of frequency bin outputs has an associated aggregate output set to a predefined binary value and a predefined minimum number of a second group of the plurality of frequency bin outputs has an associated aggregate output set to a predefined binary value. | 06-13-2013 |
20130176778 | CELL-LEVEL STATISTICS COLLECTION FOR DETECTION AND DECODING IN FLASH MEMORIES - Methods and apparatus are provided for collecting cell-level statistics for detection and decoding in flash memories. Data from a flash memory device is processed by obtaining one or more read values for a plurality of bits in a page of the flash memory device; and generating cell-level statistics for the flash memory device based on a probability that a data pattern was read from the plurality of bits given that a particular pattern was written to the plurality of bits. The cell-level statistics are optionally generated substantially simultaneously with a reading of the read values, for example, as part of a read scrub process. The cell-level statistics can be used to convert the read values for the plurality of bits to a reliability value for a bit among the plurality of bits. | 07-11-2013 |
20130176779 | INTER-CELL INTERFERENCE CANCELLATION IN FLASH MEMORIES - Inter-cell interference cancellation is provided for flash memory devices. Data from a flash memory device is processed by obtaining one or more quantized threshold voltage values for at least one target cell of the flash memory device; obtaining one or more hard decision read values for at least one aggressor cell of the target cell; determining an aggressor state of the at least one aggressor cell; determining an interference amount based on the aggressor state; determining an adjustment to the quantized threshold voltage values based on the determined interference amount; and adjusting the quantized threshold voltage values based on the determined adjustment. The quantized threshold voltage values for at least one target cell are optionally re-used from a previous soft read retry operation. The adjusted quantized threshold voltage values are optionally used to determine reliability values and are optionally applied to a soft decision decoder and/or a buffer. | 07-11-2013 |
20130176780 | DETECTION AND DECODING IN FLASH MEMORIES WITH ERROR CORRELATIONS FOR A PLURALITY OF BITS WITHIN A SLIDING WINDOW - Methods and apparatus are provided for detection and decoding in flash memories with error correlations for a plurality of bits within a sliding window. Data from a flash memory device is processed by obtaining one or more read values for a plurality of bits from one or more pages of the flash memory device; converting the one or more read values for the plurality of bits to a non-binary log likelihood ratio based on a probability that a given data pattern was written to the plurality of bits when a particular pattern was read from the plurality of bits; and decoding the plurality of bits using a binary decoder. The non-binary log likelihood ratio captures one or more of intra-page correlations and/or intra-cell correlations. A least significant bit and a most significant bit of a given cell can be independently converted and/or jointly converted to the non-binary log likelihood ratio. | 07-11-2013 |
20130185598 | MULTI-TIER DETECTION AND DECODING IN FLASH MEMORIES - Methods and apparatus are provided for multi-tier detection and decoding in flash memory devices. Data from a flash memory device is processed by obtaining one or more read values for at least one bit in a given page of the flash memory device; converting the one or more read values for the at least one bit to a reliability value; performing an initial decoding of the at least one bit in a given page using the reliability value; and performing an additional decoding of the at least one bit in the given page if the initial decoding is not successful, wherein the additional decoding uses one or more of additional information for the given page and at least one value for at least one bit from at least one additional page. | 07-18-2013 |
20130185599 | DETECTION AND DECODING IN FLASH MEMORIES USING CORRELATION OF NEIGHBORING BITS - Methods and apparatus are provided for detection and decoding in flash memories using a correlation of neighboring bits or errors in neighboring bits. Data from a flash memory device is processed by obtaining one or more read values for a plurality of bits in a given page of the flash memory device; converting the one or more read values for the plurality of bits to a reliability value for a bit among said plurality of bits based on a probability that a data pattern was written to the plurality of bits given that a particular pattern was read from the plurality of bits; and decoding the bit in the page using the reliability value. The probability that the data pattern was written to the plurality of bits given that the particular pattern was read from the plurality of bits is obtained from one or more tables. | 07-18-2013 |
20130286498 | INTER-TRACK INTERFERENCE MITIGATION IN MAGNETIC RECORDING SYSTEMS USING AVERAGED VALUES - Hardware-based methods and apparatus are provided for inter-track interference mitigation in magnetic recording systems using averaged values. Inter-track interference (ITI) is mitigated in a magnetic recording system by obtaining ITI cancellation data; and providing the ITI cancellation data for ITI mitigation, wherein the ITI mitigation is performed in combination with an averaging procedure for one or more of ITI mitigation of averaged data and averaging of ITI mitigated data. The sector is optionally decoded using the ITI mitigated samples. Samples for one or more side track sectors can also be averaged. The averaged side track samples can be provided as ITI cancellation data for ITI mitigation. The averaging procedure optionally applies a scaling factor to each read value. | 10-31-2013 |
20140002920 | Systems and Methods for Identifying Head Contact | 01-02-2014 |
20140050023 | MEMORY DEVICE HAVING COLLABORATIVE FILTERING TO REDUCE NOISE - An apparatus is described that is configured to modify a signal to at least substantially remove a noise portion from the signal. In one or more implementations, the apparatus is a collaborative filtering module that is configured to communicatively couple to a memory array having a plurality of memory cell blocks. The memory array is configured to furnish a signal representative of data stored within the plurality of memory cell blocks. The collaborative filtering module is configured to determine a noise distribution associated with the plurality of memory cell blocks and generate a noise prediction, which is based upon the noise distribution, when a read operation for the plurality of memory cell blocks is issued. The collaborative filtering module is also configured to modify the signal utilizing the noise prediction to at least substantially remove noise from the signal. | 02-20-2014 |
20140052893 | FILE DELETION FOR NON-VOLATILE MEMORY - A device includes non-volatile memory and a controller. The controller receives a write request including data and a logical address associated with a file. The controller stores the data at a data storage segment having a physical address and associates the physical address with the logical address and a file identifier for the file. The controller receives a second write request including data and the logical address associated with the file. The controller stores the data at a second data storage segment having a second physical address and associates the second physical address with the logical address and the file identifier. When a file delete request for the file is received, the controller identifies the first physical address and the second physical address using the file identifier and erases the information stored at the first data storage segment and the second data storage segment based upon the file identification. | 02-20-2014 |
20140078608 | Systems and Methods for Hard Decision Based ITI Cancellation - Embodiments of the present inventions are related to systems and methods for data processing, and more particularly to systems and methods for reducing inter-track interference in relation to processing data retrieved from a storage medium. | 03-20-2014 |
20140095110 | FLASH CHANNEL PARAMETER MANAGEMENT WITH READ SCRUB - An apparatus having a first circuit and a second circuit is disclosed. The first circuit may be configured to generate statistics of a region of a memory circuit as part of a read scrub of the region. The region may have multiple units of data. The memory circuit may be configured to store the data in a nonvolatile condition. The second circuit is generally configured to (i) track one or more parameters of the region based on the statistics, (ii) determine when one or more of the statistics of one or more outliers of the units in the region exceeds a corresponding threshold and (iii) track the parameters of the outlier units separately from the parameters of the region in response to exceeding the corresponding threshold. The parameters generally control one or more reference voltages used to read the data from the region. | 04-03-2014 |
20140126287 | Methods And Apparatus For Storing Data In A Multi-Level Cell Flash Memory Device With Cross-Page Sectors, Multi-Page Coding And Per-Page Coding - 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. | 05-08-2014 |
20140126288 | Methods And Apparatus For Storing Data In A Multi-Level Cell Flash Memory Device With Cross-Page Sectors, Multi-Page Coding And Per-Page Coding - 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. | 05-08-2014 |
20140126289 | Methods And Apparatus For Storing Data In A Multi-Level Cell Flash Memory Device With Cross-Page Sectors, Multi-Page Coding And Per-Page Coding - 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. | 05-08-2014 |
20140153126 | Systems and Methods for Old Data Inter-track Interference Compensation - Systems and methods for data processing, and more particularly to estimating or calculating interference between tracks on a storage medium. | 06-05-2014 |
20140164868 | FLASH MEMORY READ ERROR RECOVERY WITH SOFT-DECISION DECODE - An apparatus having a circuit and one or more processor is disclosed. The circuit is configured to receive a codeword from a memory. The memory is nonvolatile. The codeword generally has one or more errors. The processors are configured to generate read data by decoding the codeword repeatedly. The decoding includes a soft-decision decoding that uses a plurality of parameters calculated by (i) a first procedure, (ii) a second procedure in response to a plurality of failures of the decoding to converge using the first procedure and (iii) a third procedure in response to another failure of the decoding to converge using the second procedure. | 06-12-2014 |
20140164881 | POLICY FOR READ OPERATIONS ADDRESSING ON-THE-FLY DECODING FAILURE IN NON-VOLATILE MEMORY - An apparatus includes a non-volatile memory and a controller. The controller is operatively coupled to the non-volatile memory and configured to perform read and write operations on the non-volatile memory using codewords as a unit of read access. The controller includes an error correction engine configured to perform an error correction on codewords read from the non-volatile memory, and, if the error correction fails, to perform one or more retry procedures. The controller is further configured to perform one or more background procedures as a result of the error correction or one or more of the retry procedures not being successful and send an error message as a result of all of the retry procedures not being successful. The one or more background procedures are directed to determining a cause of the error correction failure. | 06-12-2014 |
20140177767 | METHOD AND APPARATUS FOR JOINT EQUALIZATION AND DECODING OF MULTIDIMENSIONAL CODES TRANSMITTED OVER MULTIPLE SYMBOL DURATIONS - Techniques are provided for performing joint equalization and decoding of multidimensional codes transmitted over multiple symbol durations. A reduced state sequence estimation (RSSE) decoder is provided for a multidimensional code. A multidimensional code symbol comprises a number of symbol components of lower dimensionality. The RSSE decodes comprises at least one branch metric unit that calculates branch metrics for a received signal based on intersymbol interference and intrasymbol interference estimates, the at least one branch metric unit compensating for intrasymbol interference caused by symbol components within a current multidimensional code symbol; and a decision feedback unit that processes survivor symbols to calculate the intersymbol interference estimates for different code states of the multidimensional code and channels used to transmit the multidimensional code. | 06-26-2014 |
20140247514 | Systems and Methods for ADC Sample Based Inter-track Interference Compensation - Various embodiments of the present invention provide systems and methods for mitigating inter-track interference using pre-equalized data samples. | 09-04-2014 |
20140269048 | RETENTION DETECTION AND/OR CHANNEL TRACKING POLICY IN A FLASH MEMORY BASED STORAGE SYSTEM - A method for determining a retention time in a solid state device (SSD), comprising the steps of providing a plurality of write operations to a memory, determining a reference voltage for each of the write operations, determining a difference between (i) the reference voltage after each of the write operations and (ii) a target reference voltage and if the difference is above a predetermined value, generating a flag indicating an excessive retention has occurred. | 09-18-2014 |
20140281767 | RECOVERY STRATEGY THAT REDUCES ERRORS MISIDENTIFIED AS RELIABLE - A method for applying a sequence of sensing/read reference voltages in a read channel includes (A) setting a read window based on an estimate of a read channel, (B) setting first, second, and third values of a sequence of sensing voltages to values corresponding to different ones of (i) a left-hand limit of the read window, (ii) a right-hand limit of the read window; and (iii) a point central to the read window, (C) determining whether first, second and third reads are successful, and (D) if the first, second and third reads are not successful, setting fourth and fifth values of the sequence of sensing voltages to values corresponding to different ones of (i) a point between the left-hand limit and the point central to the read window and (ii) a point between the right-hand limit and the point central to the read window. | 09-18-2014 |
20140281822 | METHOD AND APPARATUS FOR GENERATION OF SOFT DECISION ERROR CORRECTION CODE INFORMATION - A method and apparatus for generating soft decision error correction code information. The method includes generating or creating a lookup table (LUT), such as a log likelihood ratio (LLR) lookup table, characterizing a flash memory device. The method also includes loading the lookup table into the SSD controller. The method also includes accessing the lookup table to assign LLR or other characteristic values to the cells of a flash memory device. The method also includes decoding the data in a flash memory device using the soft decision information provided by the lookup table and assigned to the appropriate cells of the flash memory device. | 09-18-2014 |
20140289450 | Dynamic Log Likelihood Ratio Quantization for Solid State Drive Controllers - A method for system for dynamic channel Log Likelihood Ratio (LLR) quantization for a Solid State Drive (SSD) controller is a targeted approach to scaling which results in a scaled, quantized set of LLRs whose relative magnitude remains undisturbed from an original magnitude. The method reads a set of voltages from each channel of the SSD. The set of reads is configured in location and number for performance. Once a set is returned, the method determines an LLR for each of the voltages read resulting in a raw set of LLRs. Targeted scaling results in a scaled set of LLRs between an upper limit and a lower limit determined for reading by a decoder. Once scaled, the LLRs are rounded and quantized for use by the decoder to produce an Error Correction Code (ECC). | 09-25-2014 |
20140298131 | Priori Information Based Post-Processing in Low-Density Parity-Check Code Decoders - A low-density parity-check decoder utilizes information about hard errors in a storage medium to identify bit locations to flip log-likelihood ratios while attempting to decode codewords. The decoder iteratively flips and saturates log-likelihood ratios for bits at hard error locations and re-decodes until a valid codeword is produced. The decoder also identifies variable nodes associated with trapping sets for iterative log-likelihood ratio bit flipping. | 10-02-2014 |
20150077277 | REDUCED POLAR CODES - A method for encoding a reduced polar code is disclosed. The method generally includes steps (A) to (C). Step (A) may generate the intermediate codeword by polar code encoding input data. Step (B) may remove one or more bits from one of (i) a first part of the intermediate codeword and (ii) a second part of the intermediate codeword. Step (C) may generate an output codeword by concatenating the first part of the intermediate codeword with the second part of the intermediate codeword after the bits are removed. | 03-19-2015 |
20150082121 | METHOD OF ERASE STATE HANDLING IN FLASH CHANNEL TRACKING - An apparatus includes a non-volatile memory and a controller. The controller may be configured to track one or more channel parameters of the non-volatile memory. The controller may be further configured to estimate an erase state voltage distribution of the non-volatile memory by selecting one or more parameters of the erase state distribution from a look-up table based upon at least one of the one or more channel parameters. | 03-19-2015 |