Memory controller, memory system and operation method thereof

A memory system, comprising:

• a memory device including a plurality of memory blocks for storing data, the memory block including a plurality of memory cells;
• and
• a memory controller for controlling the memory device, wherein the memory controller is configured to:
• search, according to a number of erase cycles of the memory blocks, for a read retry table corresponding to a range to which the number of erase cycles belongs, when reading fails, the read retry table including a plurality of read bias groups;
• perform read retry operations on the memory block according to the plurality of read bias groups in the read retry table;
• and
• fetch a read retry table corresponding to a storage status of the memory blocks within the range to which the number of erase cycles belongs, according to the storage status.

An operation method for a memory system, the memory system comprising a memory device and a memory controller, the memory device including a plurality of memory blocks for storing data, the memory block including a plurality of memory cells, the memory controller being configured to control the memory device, the operation method comprising:

• searching, by the memory controller and according to a number of erase cycles of the memory block, for a read retry table corresponding to a range to which the number of erase cycles belongs, when reading fails, the read retry table including a plurality of read bias groups;
• performing, by the memory controller, read retry operations on the memory block according to the plurality of read bias groups in the read retry table;
• and
• fetching a read retry table corresponding to a storage status of the memory blocks within the range to which the number of erase cycles belongs, according to the storage status.