A memory device includes a memory array and a memory controller. The memory array includes a first memory bank, a second memory bank, and a third memory bank. The first memory bank includes a first sub memory bank. The second memory bank includes a second sub memory bank. The memory controller, according to a write command from a host, writes first data from the host to the first memory bank and second data to the second memory bank at the same time, and writes a first Hamming weight of the first data to the third memory bank. The second data is the inverse of the first data.

This application discloses example decoding methods, example decoders, and example decoding apparatuses. One example decoding method includes performing soft decision decoding on a first sub-codeword in a plurality of sub-codewords to obtain a hard decision result. It is determined whether to skip a decoding iteration. In response to determining not to skip the decoding iteration, a first turn-off identifier corresponding to the first sub-codeword is set to a first value based on the hard decision result. The first turn-off identifier indicates whether to perform soft decision decoding on the first sub-codeword in a next decoding iteration. The soft decision decoding is not performed on the first sub-codeword in the next decoding iteration when a value indicated by the first turn-off identifier is the first value. The hard decision result is stored.

A processing device in a memory system reads a sense word from a memory device and executes a plurality of parity check equations on corresponding subsets of the sense word to determine a plurality of parity check equation results. The processing device determines a syndrome for the sense word using the plurality of parity check equation results, determines whether the syndrome for the sense word satisfies a codeword criterion, and responsive to the syndrome for the sense word not satisfying the codeword criterion, performs an iterative low density parity check (LDPC) correction process, wherein at least one criterion of the iterative LDPC correction process is adjusted after a threshold number of iterations is performed.

A method of correcting data stored in a memory device includes: applying an iterative decoder to the data; determining a total number of rows in first data the decoder attempted to correct; estimating first visible error rows among the total number that continue to have an error after the attempt; estimating residual error rows among the total number that no longer have an error after the attempt; determining second visible error rows in second data of the decoder that continue to have an error by permuting indices of the residual error rows according to a permutation; and correcting the first data using the first visible error rows.

Embodiments of the present disclosure provide a scheme for decoding over a small subgraph which highly likely includes some errors. A controller is configured to: control the first decoder to decode the data, read from the memory device, using a parity check matrix for the error correction code; extract one or more subgraphs from the entire bipartite graph of the parity check matrix, which is defined by a plurality of variable nodes and a plurality of check nodes when a particular condition satisfied; and control the second decoder to decode the decoding result of the first decoder using a submatrix of the parity check matrix corresponding to the extracted subgraphs.

A data storage device includes a memory device and a controller coupled to the memory device. The controller is configured to decode data from the memory device, store a decoder level for the decoded data in a bloom filter, receive a read command for the data, and decode the data using a decoder associated with the stored decoder level. The decoder level corresponds to a decoder having a certain decoding strength. The decoder level is stored in the bloom filter as an ID, where a bloom filter may be associated with each decoder level.

Methods, systems, and devices for operating a memory device are described. An error correction bit flipping scheme may include methods, systems, and devices for performing error correction of one or more bits (e.g., a flip bit) and for efficiently communicating error correction information. The data bits and the flip bit (e.g., an error corrected flip bit) may be directly transmitted (e.g., to a flip decision component). The flip bit may be transmitted to the flip decision component over a dedicated and/or unidirectional line that is different from one or more other lines that carry data bits (e.g., to the flip decision component).

A system for a fiber-optic network includes a transceiver. The transceiver includes a fiber-optic interface unit and a host unit. The host unit includes a low-complexity error correction decoder and a high-complexity error correction decoder. One or both from the low-complexity error correction decoder and the high-complexity error correction decoder are selected to decode input data from the fiber-optic interface unit, the input data including codewords.

The subject technology provides for scanning blocks of a flash memory device for erased pages. A first codeword read from a page of a block in a flash memory device is received and provided to a first decoder for decoding. In response to receiving a first success indicator from the first decoder indicating that the first codeword was successfully decoded, first decoded data is provided from the first decoder to a second decoder for verification of the first decoded data. In response to receiving a first failure indicator from the second decoder indicating that the first decoded data was not verified, the page of the block is identified as being in an erased state based on the first success indicator received from the first decoder and the first failure indicator received from the second decoder.

A multi-channel decoder circuit associated with a multi-channel decoder system is disclosed. The multi-channel decoder circuit comprises a distributed decoder circuit comprising a set of unit decoder circuits, each unit decoder circuit configured to receive one or more codewords of a plurality of codewords associated with a plurality of input channels, and decode the one or more codewords. The multi-channel decoder circuit further comprises a distribution controller circuit configured to distribute each incoming codeword of the one or more codewords to the respective unit decoder circuit of the set of unit decoder circuits within the distributed decoder circuit, based on determining a currently available unit decoder circuit within the set of unit decoder circuits.