Transmit Antenna Selection and Analog Beamforming With Low-Resolution Phase Shifters in mmWave MISO Systems

Millimeter-wave (mmWave) communications with large-scale antenna arrays have been deemed as a key technology for future 5G networks. Analog beamforming implemented by low-resolution phase shifters (PSs) has been widely considered because of its significant advantages of low hardware complexity and power consumption. Antenna selection is an efficient approach to compensate the accuracy loss due to the use of low-resolution PSs by utilizing augmented antenna diversity. In this letter, we consider joint transmit antenna selection and analog beamformer design with low-resolution PSs to maximize the spectral efficiency of a multiple-input single-output mmWave system. We first formulate the joint design problem into a mixed-integer nonlinear programming optimization with pure binary variables, which can be solved by branch-and-bound-based algorithms. Then, a simple heuristic approach is also proposed to further reduce the complexity. Simulation results demonstrate the advantages of adopting antenna selection in low-resolution analog beamforming schemes and validate the effectiveness of the proposed algorithms.