Abstract: Devices, systems and methods for improving the convergence of a bit-flipping decoder in a non-volatile memory are described. An example method includes receiving a noisy codeword that is based on a transmitted codeword generated from an irregular QC-LDPC code, the irregular QC-LDPC code having an associated parity matrix comprising a plurality of columns of circulant matrices, computing a plurality of flipping energies for each column of a first subset of columns from the plurality of columns of circulant matrices, computing, based on the plurality of flipping energies, one or more metrics, selecting, based on the one or more metrics, a second subset of columns from the first subset of columns in an order that is different from a sequential indexing order of the second subset of columns, determining, based on processing the second subset of columns using a vertically shuffled scheduling operation, a candidate version of the transmitted codeword.

Abstract: A controller estimates optimal read threshold values for a memory device using deep learning. The memory device includes multiple pages coupled to select word lines in a memory region. The controller performs multiple read operations on a select type of page for each word line using multiple read threshold sets, obtains fail bit count (FBC) information associated with each read operation, and determines an optimal read threshold set for each word line based on the FBC information. When optimal read threshold sets for the select word lines are different each other, the controller predicts a best read threshold set using the optimal read threshold sets.

Abstract: A method of operating a storage system is provided. The storage system includes memory cells and a memory controller, wherein each memory cell is an m-bit multi-level cell (MLC), where m is an integer, and the memory cells are arranged in m pages. The method includes determining initial LLR (log likelihood ratio) values for each of the m pages, comparing bit error rates in the m pages, identifying a programmed state in one of the m pages that has a high bit error rate (BER), and selecting an assist-read threshold voltage of the identified page. The method also includes performing an assist-read operation on the identified page using the assist-read threshold voltage, determining revised LLR values for the identified page based on results from the assist-read operation, and performing soft decoding using the revised LLR values for the identified page and the initial LLR values for other pages.

Abstract: A non-volatile data storage device includes memory cells arranged in a plurality of blocks and a memory controller coupled to the memory cells for controlling operations of the memory cells. The memory controller is configured to determine if a given block is a bad m-bit multi-level block. In an m-bit multi-level block, each memory cell is an m-bit multi-level cell (MLC), m being an integer equal to or greater than 2. Upon determining that the given block is a good m-bit multi-level block, the memory controller assigns the given block to be an m-bit multi-level user block. Upon determining that the given block is a bad m-bit multi-level block, the memory controller determines if the given block is a good n-bit block. In an n-bit block, each memory cell is an n-bit cell, n being an integer less than m. Upon determining that the given block is a good n-bit block, the memory controller assigns the given block to be an n-bit user block or an n-bit write-buffer block.

Abstract: A controller optimizes read threshold values for a memory device using domain transformation. The controller determines, for the decoded data of each read operation, an asymmetric ratio (AR) and the number of unsatisfied checks (USCs), the AR indicating a ratio of the number of a first binary value to the number of a second binary value in the decoded data. The controller determines a Z-axis such that AR values of the threshold sets are arranged in a set order along the Z-axis. The controller determines an optimum read threshold set using coordinate values on the Z-axis, which correspond to a set AR value and a set USC value.

Abstract: A memory controller optimizes read threshold values for a memory device using multi-dimensional search. The controller performs a read operation on cells using a pair of default read threshold values on a multi-dimensional plane. When the read operation has failed, the controller determines program states of cells and a pair of next read threshold values based on the program states and performs an additional read operation using the next read threshold values.

Abstract: Devices, systems and methods for reducing complexity of a bit-flipping decoder for quasi-cyclic (QC) low-density parity-check (LDPC) codes are described. An example method includes receiving a noisy codeword that is based on a transmitted codeword generated from an irregular QC-LDPC code, the irregular QC-LDPC code having an associated parity matrix, storing, based on a weight of a plurality of columns of the parity matrix of the irregular QC-LDPC code, a portion of the noisy codeword corresponding to the plurality of columns in a first buffer of a plurality of buffers, and accessing and processing the portion of the noisy codeword that includes applying a vertically shuffled scheduling (VSS) scheme that uses a plurality of processing units to determine a candidate version of a portion of the transmitted codeword that corresponds to the portion of the noisy codeword.

Abstract: Devices, systems, and methods for dynamic control of a quasi-cyclic low-density parity-check (QC-LDPC) bit-flipping decoder are described. An example method includes receiving a noisy codeword based on a transmitted codeword generated from an irregular QC-LDPC code, performing a plurality of decoding iterations on the received noisy codeword, each of the plurality of decoding iterations comprising processing of N circulant matrices, performing, before processing a current circulant matrix in a current M-th iteration of the plurality of decoding iterations, operations that include computing a number of bit flips that have occurred over the processing of N previous circulant matrices, the N previous circulant matrices spanning the current M-th iteration and an (M?1)-th iteration, wherein M and N are positive integers, and wherein M?2, and updating, based on the number of bit flips, a bit-flipping threshold, and processing, based on the updated bit-flipping threshold, the current circulant matrix.

Abstract: A descrambler receives data from a memory device. The descrambler calculates a sub-syndrome weight for multiple bits in each of the plurality of descrambled sequences using a set parity check matrix to generate multiple sub-syndrome weights, one for each of the plurality of descrambled sequences. The descrambler selects a sub-syndrome weight among the multiple sub-syndrome weights. The descrambler determines, as a correct scrambler sequence for descrambling the data, a scrambler sequence corresponding to the selected sub-syndrome weight, among the plurality of scrambler sequences.

Abstract: Systems, memory controllers, decoders and methods perform decoding by exploiting differences among word lines for which soft decoding fails (failed word lines). Such decoding generates extrinsic information for codewords of failed word lines based on the soft decoding. The soft information obtained during the soft decoding is updated based on the extrinsic information, and the updated soft information is propagated across failed word lines. Low-density parity-check (LDPC) decoding of codewords of failed word lines is performed with the updated soft information.

Abstract: Devices, systems and methods for improving the convergence of a bit-flipping decoder in a non-volatile memory are described. An example method includes receiving a noisy codeword that is based on a transmitted codeword generated from an irregular QC-LDPC code, the irregular QC-LDPC code having an associated parity matrix comprising a plurality of columns of circulant matrices, computing a plurality of flipping energies for each column of a first subset of columns from the plurality of columns of circulant matrices, computing, based on the plurality of flipping energies, one or more metrics, selecting, based on the one or more metrics, a second subset of columns from the first subset of columns in an order that is different from a sequential indexing order of the second subset of columns, determining, based on processing the second subset of columns using a vertically shuffled scheduling operation, a candidate version of the transmitted codeword.

Abstract: A data processing system includes a storage medium, and a controller including a data processing block, configured to receive data from a host, transmit the received data to the storage medium, read data from the storage medium in response to a read request from the host, and decode the read data by the data processing block according to multiple decoding modes. The data processing block includes a first decoder and a second decoder, and is configured to manage the first decoder and the second decoder to run the decoding for the read data, and activate a fast decoding having shorter latency than a normal decoding after a fast decoding condition is satisfied.

Abstract: Examples include techniques to use intrinsic information when implementing a bit-flipping algorithm. An error correction control (ECC) decoder uses the intrinsic information to decode a low density parity count (LDPC) codeword. The intrinsic information including bits of a copy of a received LDPC codeword are compared to bits for variable nodes during an iteration of the bit-flipping algorithm to aid a determination as whether one or more bits for the variable nodes are to be flipped.

Abstract: Techniques are described for improving the decoding latency and throughput of an error correction system that includes a bit flipping (BF) decoder, where the BF decoder uses a bit flipping procedure. In an example, different decoding parameters are determined including any of a decoding number of a decoding iteration, a checksum of a codeword, a degree of a variable node, and a bit flipping threshold defined for the bit flipping procedure. Based on one or more of these decoding parameters, a decision can be generated to skip the bit flipping decoding procedure, thereby decreasing the decoding latency and increasing the decoding throughput. Otherwise, the bit flipping decoding procedure can be performed to compute a bit flipping energy and determine whether particular bits are to be flipped or not. Hence, the overall performance (e.g., bit error rate) is not significantly impacted.

Abstract: Memory controllers, decoders and methods perform decoding of a codeword comprising multiple bits. For a select one of those bits, which belongs to at least one component codeword of the codeword, at an iteration of decoding, the following operations are performed. Channel information for the select bit is biased based on degree of the select bit. A reliability indicator of an initial decision as to whether to flip the select bit is computed based on the initial decision and the biased channel information. The reliability indicator is compared with an adaptive threshold, which is determined based on the degree of the select bit and unsatisfied check (USC) information from the initial decision. A decision is then made as to whether to flip the select bit. The decision and syndromes of each component codeword to which the select bit belongs are updated based on the compare operation.

Abstract: A memory controller optimizes read threshold values for a memory device using multi-dimensional search. The controller performs a read operation on cells using a pair of default read threshold values on a multi-dimensional plane. When the read operation has failed, the controller determines program states of cells and a pair of next read threshold values based on the program states and performs an additional read operation using the next read threshold values.

Abstract: Devices, systems and methods for maintaining consistent write latencies in non-volatile memory devices are described. An example method includes receiving, from a host device, a write command, computing an actual latency of the write command based on an arrival of the write command and a completion of the write command, incrementing, based on the actual latency, one or more of a plurality of counters, updating, based on the plurality of counters subsequent to the incrementing, a value of a minimum duration, and transmitting, at a time instance determined based on an updated value of the minimum duration, an indication of the completion of the write command to the host device, wherein the minimum duration represents a minimum latency between the arrival and the transmitting, and wherein transmitting at the time instance enables an observed latency to remain within a predetermined tolerance of an average value of the actual latency.

Abstract: Techniques are described for improving the decoding latency and throughput of an error correction system that includes a bit flipping (BF) decoder, where the BF decoder uses a bit flipping procedure. In an example, different decoding parameters are determined including any of a decoding number of a decoding iteration, a checksum of a codeword, a degree of a variable node, and a bit flipping threshold defined for the bit flipping procedure. Based on one or more of these decoding parameters, a decision can be generated to skip the bit flipping decoding procedure, thereby decreasing the decoding latency and increasing the decoding throughput. Otherwise, the bit flipping decoding procedure can be performed to compute a bit flipping energy and determine whether particular bits are to be flipped or not. Hence, the overall performance (e.g., bit error rate) is not significantly impacted.

Abstract: A control of a memory system includes firmware and one error correction code (ECC) module. The module includes a power control engine and ECC components, each ECC component including a power monitor and a power controller. The firmware configures a window of time and a power consumption rate of a select ECC component depending on characteristics of the memory system. The power monitor of the select ECC component measures a power consumption of the select ECC component within the window. The power control engine receives the measurement of power consumption, decides a next power level for the select ECC component, and controls the power controller of the select ECC component such that the select ECC component operates at the next power level.

Abstract: Devices, systems and methods for reducing complexity of a bit-flipping decoder for quasi-cyclic (QC) low-density parity-check (LDPC) codes are described. An example method includes receiving a noisy codeword that is based on a transmitted codeword generated from an irregular QC-LDPC code, the irregular QC-LDPC code having an associated parity matrix, storing, based on a weight of a plurality of columns of the parity matrix of the irregular QC-LDPC code, a portion of the noisy codeword corresponding to the plurality of columns in a first buffer of a plurality of buffers, and accessing and processing the portion of the noisy codeword that includes applying a vertically shuffled scheduling (VSS) scheme that uses a plurality of processing units to determine a candidate version of a portion of the transmitted codeword that corresponds to the portion of the noisy codeword.