COST IC1004 Temporary Document: Characterization of Interference for Over the Air Terminal Testing

The purpose of so-called over the air (OTA) testing of various MIMO devices is to include in the test the properties of both the antenna system as well as the transceiver. In the development of test procedures, much of the focus has been on modeling the properties of the radio channel of the desired signal. However, interfering signals also needs to be considered. The aims of the work described in this contribution is firstly to determine the level of the interference with respect to the desired signal and, secondly, to determine suitable interfering power distribution models, depending on the spherical angle.
To this end, a small series of measurements has been carried out using a spectrum analyzer and a dual-polarized horn antenna. The horn was attached to a programmable device which can point the horn into arbitrary directions on a sphere centered at a given location. For each geographical measurement location a full dual-polarized scan was performed, covering the sphere in azimuth angle and most in elevation angle.
Different locations were investigated, namely rural, sub-urban, and urban, all outdoors. The spectrum from 500–3000 MHz was measured in steps of about 350 kHz.