Contents I. Introduction
Emerging bandwidth-demanding services such as augmented/virtual reality put great a strain on wireless systems [1]. Millimeter-wave (mmWave) communications spanning a wide frequency range can provide a data rate of Gbps, which have been widely studied [2], [3]. Compared to signals at sub-6GHz frequencies [1], one differentiating factor in mmWave signals is the ten-fold decrease in wavelength. The decrease in wavelength enables packing massive mmWave antennas into small form factors [2]. From the Friis free-space equation [4], however, the penetration loss at mmWave frequencies is more excessive than that at sub-6GHz frequencies, and therefore, mmWave signals are more sensitive to blockages than sub-6GHz signals [5], [6].
