10 UE Co-Pol., 2 UE XPD, 2 UE Co-Pol., 1 UE XPD, UE Throughput (Mbps) Figure 11.36 Individual user throughput. © 2009 by Taylor & Francis Group, LLC Long Term Evolution: 3GPP LTE Radio and Cellular Technology 11.4.5 Discussion of Results Spatial multiplexing with multiple antennas is an important PHY layer aspect to deliver high throughput in OFDMA systems. Spatial multiplexing relies on chan- nel scattering effects in wireless multipath environments. In practical cellular sys- items, such channel conditions may not commonly exist to support multiplexing. Multiplexing with polarized antennas is then shown to be a suitable solution. Our measurement results, which were performed in LOS conditions, demonstrate the throughput gains by using polarized antennas. Throughput analysis shows that orthogonally polarized antennas considerably outperform copolarized antennas at high SNRs. This spectral efficiency gain is shown to better influence multiuser scheduling. It is seen that orthogonally polarized antennas are more suitable for user fairness in OFDMA scheduling. 11.4.5.1 Summary of Field Trial Results As shown in the previous sections, we could verify that the 3GPPLTE air interface, which is still under discussion as this book is edited, can be operated indoors as well as outdoors and achieve very high data rates. Robustness to channel conditions has also been shown for coverage areas up to 800 m with mobility. Furthermore, we could demonstrate the benefits of the new 3GPP-LTE air interface with a new cross-layer MAC architecture of link adaptation, transmit MIMO mode selec- tion, and MCS level selection, all of which are frequency dependent. The plot in Figure 11.37 gives an overview of the coverage in a single-cell/single-sector scenario measured in downtown Berlin. The base station was installed at a height of about 60 m on top of the HHI building and the XPD BS antenna pointed southwest toward the campus of the University of Technology in Berlin. The sector antenna had an 11-dBi antenna gain and a 60° horizontal 