Memory system having non-volatile memory

A method of operating a memory system comprising a non-volatile memory including a word line and a plurality of memory cells connected to the word line, the method comprising:

• dividing an n-dimensional space into a plurality of regions by a plurality of hyperplanes, where n is an integer of 2 or more;
• assigning a representative point of a read level for reading data from a plurality of memory cells to each region;
• providing a binary tree for selecting any of the plurality of regions;
• tracing a branch node in the binary tree by determining whether a first read level is higher or lower than a voltage level at the branch node of the binary tree;
• when determining the first read level is higher or lower than the voltage level of the branch node in the binary tree, determining whether a voltage difference between the first read level and the voltage level of the branch node is within a voltage margin or not;
• when reaching the leaf node of the binary tree by tracing the branch node in the binary tree, determining a read level of a representative point assigned to a region correlated with a leaf node among the plurality of divided regions as a second read level corresponding to the first read level, and
• causing the non-volatile memory to read data of the plurality of memory cells by applying a voltage of the determined second read level to the word line.