a- tions in our transmit mode selection probabilities in MIMO configuration. 11.2.2 Detection Algorithms the downlink with K transmitters, we assume an MMSE filter at the receiver for the spatial separation of the multiplexed streams. An MRC is applied if only a single stream is transmitted. The receiver processing is performed in the frequency domain per subcarrier. For the experiments, a constant power profile over the allo- cated subcarriers was implemented and no beam forming was used. 11.2.2.1 MIMO-OFDM Downlink The parameter set for the PHY implementation was chosen according to working assumptions around November 2005. A detailed description of these assumptions is found in Table 11.1. 11.2.3 Measurement Scenarios For the experiments, we set up a basic configuration of one BS and one UE in an interference-free environment (no other BS or UEs are active during the experi- ments). Note that this is a single-cell, single-user setup, where we cannot benefit from multiuser diversity. On the other hand, we also do not suffer from intercell interference. The setup allows us to study the gains from the implemented multian- tenna techniques as in an isolated hot-spot scenario. 11.2.3.1 XPD Antennas It is common knowledge that MIMO performance degrades with the lack of spatial decorrelation. This is of concern in outdoor scenarios, where line of sight conditions exist. However, cross-polarized discrimination (XPD) antennas can be used for polarization multiplexing [4,5,7] to overcome this problem. A detailed analysis of XPD antennas and copolarized antennas is offered in the next section. Indoor. The cross-polarized BS antenna (+45°) is positioned in the corner of a typical office room of size 20 m X 8 m m and is looking into the center of the room. The office is equipped with standard office furniture and has doors at three sides of the room; the third side consists of a glass front. The UE is moved on a © 2009 by Taylor & Francis Group, LLC Long Term Evolution: 3GPP LTE Radio and Cellular Technology NSN facilities