A decoding method and associated circuit are provided. The circuit includes a first memory, a decoder and a control circuit. In operations of the circuit, the first memory is configured to receive a data stream; the decoder is configured to receive the data stream to sequentially generate a plurality of frames, and sequentially decode the plurality of frames to respectively generate a plurality of codewords; and the control circuit is configured to determine an allowed maximum iteration count for decoding a current frame according to an iteration count for successfully decoding at least one previous frame of the current frame.

Devices, systems, and methods for improving performance of an iterative 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 a low-density parity-check (LDPC) code, and performing, on the noisy codeword, a message passing algorithm. As part of the message passing algorithm, a check node is configured to receive each of multiple messages from a corresponding variable node connected to the check node. Then, the check node identifies, based on the multiple messages, check node unit (CNU) parameters, and maps a concatenation of the CNU parameters to a bit string that has a length less than that of the concatenation. The bit string, which is a compressed form of the CNU parameters, is stored in a CNU register, and used to process the noisy codeword to determine a candidate version of the transmitted codeword.

Method and apparatus for decoding error correction code (ECC) code words. Reference voltages are used to extract a selected code word from a communication channel. The selected code word is processed by an ECC decoder, and an initial syndrome weight is determined indicative of unresolved parity errors. A coarse search operates to concurrently adjust, over a first succession of iterations, each of the reference voltages. A subsequent fine search operates, over a second succession of iterations, to individually adjust the reference voltages. Decoding and syndrome weight determination continues over each iteration until a minimum syndrome weight is obtained, after which a user data content of the code word is decoded. The coarse search may transition the decoder from a saturated operational region to a linear operational region. The decoder may be a low density parity check (LDPC) decoder.

Apparatuses and methods related to correcting errors can include using FD decoders and AD decoders. Correcting errors can include receiving input data from the memory array, performing a plurality of operations associated with an error detection on the input data, and providing, based on processing the input data, output data, a validation flag, and a plurality of parity bits to a second decoder hosted by a controller coupled to the memory device.

In some embodiments, a bandwidth constrained equalized transport (BCET) communication system comprises a transmitter that transmits a signal, a communication channel that transports the signal, and a receiver that receives the signal. The transmitter can comprise a pulse-shaping filter that intentionally introduces memory into the signal, and an error control code encoder that is a low-density parity-check (LDPC) error control code encoder. The error control encoder comprises code that is optimized based on the intentionally introduced memory into the signal, a code rate, a signal-to-noise ratio, and an equalizer structure in the receiver. In some embodiments, the communication system is bandwidth constrained, and the transmitted signal comprises an information rate that is higher than for an equivalent system without intentional introduction of the memory at the transmitter.

A method and apparatus is described for assigning columns of an LDPC H matrix to a plurality of decoding logics for efficient decoding of codewords. The rows of the LDPC H matrix are evaluated in a number of different orderings, and for each row in each ordering, a number of columns containing non-zero circulants are determined that cannot be evenly distributed to a plurality of decoding logics. As each row is evaluated, one or more columns of the LDPC H matrix are assigned to temporary bins for storage. After the LDPC H matrix has been evaluated a plurality of times, the arrangement that resulted in the fewest number of mismatched columns is selected, and the columns of the LDPC H matrix that were assigned to the temporary storage bins for that particular row arrangement is used to assign the columns in the bins to the plurality of decoding logics.

In one implementation, the disclosure provides a system including a detector configured to generate an output of a first log-likelihood ratio for each bit in an input data stream. The system also includes at least one look-up table providing a mapping of the first log-likelihood ratio to a second log-likelihood ratio. The mapping between the first log-likelihood ratio and the second log-likelihood ratio is non-linear. The system also includes a decoder configured to generate an output data stream using the second log-likelihood ratio to generate a value for each bit in the input data stream.

In one implementation, the disclosure provides a system including a detector configured to generate an output of a first log-likelihood ratio for each bit in an input data stream. The system also includes at least one look-up table providing a mapping of the first log-likelihood ratio to a second log-likelihood ratio. The mapping between the first log-likelihood ratio and the second log-likelihood ratio is non-linear. The system also includes a decoder configured to generate an output data stream using the second log-likelihood ratio to generate a value for each bit in the input data stream.

Devices and techniques for variable read throughput control in a storage device are described herein. Bits from can be received for a read that is one of several types assigned to reads. A low-density parity-check (LDPC) iteration maximum can be set based on the type. LDPC iterations can be performed up to the LDPC iteration maximum and a read failure signaled in response to the LDPC iterations reaching the LDPC iteration maximum.

Systems and methods for implementing data protection techniques with symbol-based variable node updates for binary low-density parity-check (LDPC) codes are described. A semiconductor memory (e.g., a NAND flash memory) may read a set of data from a set of memory cells, determine a set of data state probabilities for the set of data based on sensed threshold voltages for the set of memory cells, generate a valid codeword for the set of data using an iterative LDPC decoding with symbol-based variable node updates and the set of data state probabilities, and store the valid codeword within the semiconductor memory or transfer the valid codeword from the semiconductor memory. The iterative LDPC decoding may utilize a message passing algorithm in which outgoing messages from a plurality of multi-variable nodes are generated using incoming messages (e.g., log-likelihood ratios or L-values) from a plurality of check nodes.