Effectiveness of Terminal Antenna Employing Orthogonal Polarizations and Patterns in Outdoormultiuser Mimo System

This report presents experimental results on a Multi-User MultiInput Multi-Output (MU-MIMO) channel of an antenna with orthogonal patterns and polarizations in an outdoor urban area. The antenna configuration employing orthogonal patterns and polarizations is useful in achieving a small terminal antenna since many antennas can be placed in the same location. The properties of this antenna are compared to an antenna array that has only vertical or horizontal polarization in this environment. The measurement results indicate that the antenna with orthogonal polarizations and patterns can always provide fairly high Signal to Noise Ratio (SNR) properties when two in three antennas are chosen. We verified the MU-MIMO transmission properties and found that the antenna with only a single polarization causes serious capacity deterioration when the antenna is inclined horizontally. On the contrary, the antenna in which each element has a polarization or pattern that is different to the others can provide a high channel capacity consistently even when the antenna is placed in any direction. The measured results indicate the effectiveness of the combination of the antenna selection and the use of the orthogonal antennas, which can enhance the channel capacity by up to 50%.