Method and apparatus for estimating read levels of nonvolatile memory and for programming pilot signals used for such estimation

A method, executed by a memory controller, for estimating read levels of a nonvolatile memory includes reading voltages stored by memory cells of a page space within the nonvolatile memory to which pilot signals of a predetermined symbol are programmed. The number of memory cells are identified whose voltages, read from the page space, are less-than/greater-than a read-voltage applied in reading the voltages stored by the memory cells. A voltage to be applied for reading data stored in the page space is estimated based upon the identified number of memory cells.