Beamforming is indispensable in the operation of 60-GHz millimeter-wave directional multi-gigabit Wi-Fi. Simple power method and its extensions enable the transmitting and receiving antenna arrays to form a beam for single spatial stream. To further improve the spectral efficiency in future 60-GHz directional Wi-Fi, alternating least square (ALS) algorithm can form multiple beams between the transmitter and receiver for multi-input-multi-output (MIMO) operations. For both shared and split MIMO architecture, the ALS beamforming algorithm can be operated in both frequency-flat and frequency-selective channels. In the split architecture, MIMO beamforming approximately maximizes the capacity of the beam-formed MIMO channel.
@article{arxiv.1403.7697,
title = {MIMO Beamforming in Millimeter-Wave Directional Wi-Fi},
author = {Keang-Po Ho and Shi Cheng and Jianhan Liu},
journal= {arXiv preprint arXiv:1403.7697},
year = {2014}
}