Millimeter wave systems offer high date rate due to huge bandwidth but suffers from poor link budget. This is due to the blockage of the millimeter wave signal by the obstacles of size comparable to that of the wavelength of the signal. Various analysis in improving the signal strength is reported. One of them suggests use of directional antenna which guarantees signal delivery if line of sight communication between the transmitter and receiver exists. The other alternative scheme is Multi Input Multi Output (MIMO) beamforming that uses the channel statistics to steer the beam thereby improving the multiplexing gain and beamforming gain. In this paper, extensive research work carried out by us in MMW MIMO at 60 GHz covering aspects related to MIMO fixed-beam, adaptive beam and multibeam beamformers addressing line-of-sight and non-line-of-sight channel for MMW 60 GHz system is reviewed.
S. Kirthiga and Dr. Jayakumar M., “Performance Studies and Review of Millimeter Wave MIMO Beamforming at 60 GHz”, Procedia Technology, vol. 21, pp. 658–666, 2015.