Memory system and decoding method
AssigneeToshiba Memory Corporation
InventorDaiki WATANABE
Life of this patent
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Abstract
According to one embodiment, a memory system includes a nonvolatile memory and a memory controller. The memory controller calculates a reliability metric on the basis of at least a soft-decision input value calculated on the basis of read information that is read from the nonvolatile memory, and a decoded word, stores reference information that is a history of a plurality of reliability metrics or statistical information obtained from the history, calculates reliability from the reliability metric by using correspondence information, calculates decoding information on the basis of the decoded word and the reliability, and updates the correspondence information on the basis of the reference information.
Claims20
A memory system, comprising:
- a nonvolatile memory that stores an error correction code;
- and
- a memory controller, wherein
- the memory controller
- performs processing of acquiring read information from the nonvolatile memory,
- calculates a reliability metric that is information having a correlation with reliability of a decoded word on the basis of a soft-decision input value calculated on the basis of at least the read information, and the decoded word decoded by the soft-decision input value,
- stores reference information that is a history of a plurality of the reliability metrics or statistical information obtained from the history,
- calculates the reliability from the reliability metric by using correspondence information for calculating the reliability from the reliability metric,
- calculates decoding information on the basis of the decoded word and the reliability, and
- updates the correspondence information on the basis of the reference information.
A method of controlling a nonvolatile memory, the method comprising:
- acquiring read information from the nonvolatile memory that stores an error correction code;
- calculating a reliability metric that is information having a correlation with reliability of a decoded word on the basis of a soft-decision input value calculated on the basis of at least the read information, and the decoded word decoded by the soft-decision input value;
- storing reference information that is a history of a plurality of the reliability metrics or statistical information obtained from the history;
- calculating the reliability from the reliability metric by using correspondence information for calculating the reliability from the reliability metric;
- calculating decoding information on the basis of the decoded word and the reliability;
- and
- updating the correspondence information on the basis of the reference information.
Dependencies are inferred from the claim text.