  Hybrid analog and digital beamforming (HBF) has been recognized as an
attractive technique offering a tradeoff between hardware implementation
limitation and system performance for future broadband millimeter wave (mmWave)
communications. In contrast to most current works focusing on the HBF design
for orthogonal frequency division multiplexing based mmWave systems, this paper
investigates the HBF design for single carrier (SC) systems due to the
advantage of low peak-to-average power ratio in transmissions. By applying the
alternating minimization method, we propose an efficient HBF scheme based on
the minimum mean square error criterion. Simulation results show that the
proposed scheme outperforms the conventional HBF scheme for SC systems.
