A memory system includes a nonvolatile memory and a memory controller. The nonvolatile memory has data encoded with an error correction code stored therein. The memory controller reads data from the nonvolatile memory, calculates likelihood information from the read data and an LLR table for calculating the likelihood information, determines a parameter for a decoding process of the read data based on the likelihood information, executes the decoding process based on the determined parameter, and outputs a decoding result obtained by the decoding process.

A decoding circuit and a decoding method based on the Viterbi algorithm are provided. The decoding method includes the following steps: decoding an encoded data based on the Viterbi algorithm to generate a decoded data; performing error correction on the decoded data to obtain a data content of the encoded data; comparing the decoded data and the data content to generate bit correction information; using the encoded data to calculate multiple first branch metrics based on the Viterbi algorithm, the first branch metrics corresponding to a target bit of the data content; adjusting at least one of the first branch metrics based on the data content and the bit correction information to generate multiple second branch metrics; and selecting the first branch metrics or the second branch metrics based on the bit correction information.

A method of correcting one or more bit errors in a memory device includes retrieving a codeword from a memory device. The codeword includes a data and an error correcting code. The method further includes determining whether the one or more bit errors are present in the retrieved codeword and correcting the retrieved codeword for the one bit error in response to determining one bit error is present in the retrieved codeword. The method also includes flipping a bit of the retrieved codeword in response to determining a plurality of bit errors is present in the retrieved codeword and correcting the retrieved codeword for the plurality of bit errors based on the bit-flipped codeword.

The present disclosure includes apparatuses and methods for estimating an error rate associated with memory. A number of embodiments include sensing data stored in a memory, performing an error detection operation on the sensed data, determining a quantity of parity violations associated with the error detection operation, and estimating an error rate associated with the memory based on the determined quantity of parity violations.

The disclosure provides a method and a polar code decoder for determining a to-be-flipped bit position when performing a successive cancellation list flip operation. The method includes: obtaining a polar code decoding tree generated by performing a successive cancellation list (SCL) operation on a polar code segment, and the polar code segment includes multiple bit positions, and each bit position in the polar code decoding tree includes multiple surviving paths and multiple pruned paths; in a post-processing stage for the SCL operation, estimating a correct path probability of each of the surviving paths and the pruned paths of the i-th bit position and accordingly estimating a reliability for the i-th bit position; selecting a specific bit position among the bit positions based on the reliability of each bit position; and performing an SCL flip operation on the polar code decoding tree based on the specific bit position.

A method of decoding a polar coded signal includes determining channel reliabilities for a plurality of polar coded bit channels in a data communication system including a plurality of frozen bit channels and non-frozen bit channels, selecting a frozen bit channel, calculating a likelihood value for a bit estimate associated with the frozen bit channel, generating a hard decision value for the bit estimate in response to the likelihood value, comparing the hard decision value for the bit estimate to a known value of a frozen bit transmitted on the frozen bit channel, in response to determining that the hard decision value for the bit estimate differs from the known value of the frozen bit transmitted on the frozen bit channel, updating an accumulated uncertainty, comparing the accumulated uncertainty to a threshold, and determining that a decoding error has occurred in response to the comparison.

A method of correcting one or more bit errors in a memory device includes retrieving a codeword from a memory device. The codeword includes a data and an error correcting code. The method further includes determining whether the one or more bit errors are present in the retrieved codeword and correcting the retrieved codeword for the one bit error in response to determining one bit error is present in the retrieved codeword. The method also includes flipping a bit of the retrieved codeword in response to determining a plurality of bit errors is present in the retrieved codeword and correcting the retrieved codeword for the plurality of bit errors based on the bit-flipped codeword.

A memory system includes a memory device and a controller. The memory device is configured to supply a read voltage into a plurality of non-volatile memory cells and transfer values obtained from the plural non-volatile memory cells. The controller is coupled to the memory device via at least one channel. The controller adjusts a level of the read voltage based on a cell difference probability (CDP) calculated from the values when a read operation to the plurality of non-volatile memory cells fails.

A decoding system, a decoding controller, and a decoding control method are provided. In the decoding system, a decoding controller is disposed between two adjacent decoders. The decoding controller determines whether to perform turn-off based on a non-turn-off indication received by a previous-stage decoder, a turn-off indication output by the previous-stage decoder, and historical turn-off probability statistics. This is equivalent to adding a buffer zone between the two adjacent decoders.

A memory storage device including a memory storage array and a memory controller is provided. The memory storage array is configured to store data. The memory controller is coupled to the memory storage array. The memory controller is configured to write to-be-written data to the memory storage array. The to-be-written data includes a plurality of data bits and a flip bit. The memory controller performs a verification operation on the to-be-written data to determine whether the data bits includes error bits and records information of the error bits. The memory controller, determines, according to a quantity of the error bits, whether to invert parities of the data bits and the flip bit, and records the parity of the flip bit. In addition, a data access method is also provided.