A simple transmit beamforming technique by beam identification based on the energy detected at the receiver

In this paper transmit beamforming based on direction estimation is considered to enhance the reliability of data transmission. For the transmit beam design, we propose the simple beam design based on the direction-of-departure (DOD) to avoid the high computational angle estimation techniques. The proposed beam design technique approximates the wireless channels by selecting one dominant steering vector for the transmit beamformer. To minimize the feedback data, only the index of the best beam is fed back to the transmitter. Orthogonal codes are utilized to differentiate the largest energy beam from the others at the receiver side. The proposed scheme is thus applicable to both the rich scattering and line-of-sight (LOS) environments. The hybrid scheme is also discussed as the solution when the estimated beam is not acceptable for the beamforming.