ds use measurements in anechoic chambers, where the effect of multiantenna solutions is not directly measurable. It is clearly seen from drive tests that multian- tenna solutions do provide significant improvements of throughput in an environ- ment with rich scattering (i.e., indoors or in urban areas) compared to SISO (single input, single output) solutions. The problem with drive tests, however, is that most of the time they give dif- ferent results because the environment is under constant change. It is therefore normally not possible to compare the performance of two different multiantenna devices because they will show different throughput results in different environ- ments and at different times. Thus, there is a need for a repeatable testing method- ology to check the throughput of multiantenna devices in an environment with rich scattering. This environment should preferably have rich scattering that is repeat- able as well as isolated from outside interference that may affect the measurements. The reverberation chamber fulfills these requirements. It is a shielded room (often with better than 100-dB isolation), with a repeatable fading environment follow- ing a Rayleigh distribution (see Figure 12.11), similar to the distribution in real indoor or urban environments. Objects in the reverberation chamber located more © 2009 by Taylor & Francis Group, LLC Long Term Evolution: 3GPP LTE Radio and Cellular Technology Figure 12.11 Simulation of the field in a reverberation chamber. It is Rayleigh distributed. This is similar to the distribution found in office environments and urban areas. than 0.5 wavelength from each other will experience independent fading. By plac- ing a multiantenna base station and multiantenna terminal inside the chamber a few wavelengths apart, it is possible to measure the throughput in the uplink and downlink in a repeatable way. To test that this works in praxis, Bluetest, together with Sony Ericsson [53], per- formed a project [54], briefly described later, within the Swedish Chas