Experimental Evaluation of Outdoor-to-Indoor Mimo Systems with a Multi-Antenna Handset

In this paper, we present empirically based results on the spectral efficiencies of 4×4 multiple-input multiple-output (MIMO) wireless systems in an outdoor-to-indoor propagation scenario. Field channel measurements are performed using a compact four-element prototype handset with planar inverted-F antennas. From the measured channels, the spectral efficiencies of several MIMO techniques are calculated and compared. These techniques are open-loop and closed-loop spatial multiplexing, eigen-beamforming, and multi-mode transmission. The obtained results show that significant MIMO capacity gains are achievable with the multi-antenna handset in the propagation environment under study.