Environment-oriented beamforming for space-time block coded multiuser MIMO communications

Multiple antennas are mounted at both transmitters and receivers to exploit the multipath environment and achieve a channel capacity that grows with the number of antennas. Space-time block coded transmission is employed and polarization diversity has been considered for such systems. We heuristically combine eigenbeamforming and Alamouti STBC with polarization diversity. The beamforming maximizes output signal-to-interference-plus-noise-ratios (SINRs) before STBC decoders. STBC decoding process is modified to adopt beamforming. It is found that the beamforming is environment-oriented in that it forms a directive beam pattern toward impinging waves´ directions-of-arrival (DOAs) with respect to the dual polarized antenna (DPA) array in a high Rician-K and cross polarization discrimination (XPD) environment. The performance of the Alamouti scheme is boosted with the antenna array directivity gain.