A practical SDMA protocol for 60 GHz millimeter wave communications

We study spatial division multiple access in 60 GHz millimeter wave communications and focus on estimation of the optimal transmit beamforming vectors for stations and optimal receive beamforming vectors for the access point. An iterative antenna training protocol is developed, where the optimal transmit/ receive beamforming vectors are computed without explicit knowledge of the actual wireless channels. The proposed training method is especially attractive to systems with a much smaller number of RF chains relative to the number of antenna elements, thanks to its low training overhead.