Disclosed herein are related to a memory system including unit storage circuits. In one aspect, each of the unit storage circuits abuts an adjacent one of the unit storage circuits. In one aspect, each of the unit storage circuits includes a first group of memory cells, a second group of memory cells, a first sub-word line driver to apply a first control signal to the first group of memory cells through a first sub-word line extending along a direction, and a second sub-word line driver to apply a second control signal to the second group of memory cells through a second sub-word line extending along the direction. In one aspect, the memory system includes a common word line driver abutting one of the unit storage circuits and configured to apply a common control signal to the unit storage circuits through a word line extending along the direction.