On closed-loop transmit beamforming with simple beam-control commands

Transmit beamforming in frequency-division duplex wireless systems typically requires the channel state information of the forward link which is not easily available at base stations. We present a novel concept of transmit beamforming that operates without channel state information but based on beam-control commands in an analogous fashion to the well-known open-/closed-loop power control in cellular wireless communication systems. Simulation results show that the proposed operating principle is sufficiently effective in steering beam patterns toward multiple moving mobiles and also able to maintain the signal quality at a desired level expressed in SINR.