I. Introduction
With the exponential growth in the number of users and the diversity of the broadband applications in next-generation communication systems, the ever-increasing need to explore higher bandwidths, reveals the pivotal role of mmWave communications in future wireless networks. However, given the high path-loss and poor scattering associated with mmWave communications, effective beamforming techniques integrating a large number of antennas are required to ensure satisfactory quality of service (QoS).