An Efficient Low-Complexity Method to Calculate Hybrid Beamforming Matrices for mmWave Massive MIMO Systems

In the context of a massive MIMO system, number RF chains increases prohibitively. To solve problem, hybrid beamforming (BF) has been proposed. Nevertheless, amplitude constraint analog part in BF limits achieving optimal performance given by digital BF. Some studies have conducted recently to relax deploying multiple phase shifters and switches (that select shifters) structures. The tremendous structure makes problem switch state selection very complex. this paper, we propose an efficient low-complexity algorithm obtain states. proposed algorithm, decompose main into sub-ones reduce complexity using finite search space. results our study suggest that solution will be attainable searching through less than 1% space, if levels exceeds 14. Moreover, potential perfectly implement linear beamformers, designed for fully architectures, structure, while applying minimum chains. Finally, simulation prove efficiency confirm sufficiency achieve just few fixed shifters.