  For massive MIMO public channel with any sector size in either microwave or
millimeter wave (mmwave) band, this paper studies the beamforming design to
minimize the transmit power while guaranteeing the quality of service (QoS) for
randomly deployed users. First the ideal beampattern is derived via Parseval
Identity, based on which a beamforming design problem is formulated to minimize
the gap with the idea beampattern. The problem is transformable to a
multiconvex one and an iterative optimization algorithm is used to obtain the
full-digital beamformer. In addition, with the help of same beampattern
theorem, the power amplifier (PA) efficiency of the beamformer is improved with
unchanged beampattern. Finally, the practical hybrid implementation is obtained
that achieves the full-digital beamformer solution. Simulations verify the
advantages of the proposed scheme over existing ones.
