A novel antenna concept for double-directional channel measurements

In this paper, a novel concept for the characterization of the double-directional mobile radio channel is presented. It is based on a broad-band real-time channel-sounding device together with appropriate antenna arrays, thus forming a multiple-input-multiple-output system. For the propagation measurements within the 5.2-GHz wireless local area network band presented here, a uniform linear antenna array at the receiver site and a switched multibeam antenna at the transmitter site have been employed. By application of the multibeam antenna, the entire azimuthal range of 360° is covered without ambiguities. The measurement data obtained with this platform in a simple synthetic scenario, as well as in a typical multipath environment, is then analyzed in terms of the propagation path properties. Using the three-dimensional estimation of signal parameters via rotational invariance techniques algorithm together with a proper Fourier transform, the channel parameters of all relevant multipaths such as delay, direction of arrival, direction of departure, and path loss are extracted from the measurement data. For both scenarios, the obtained estimated paths are verified to the underlying physical propagation environment by means of geometrical considerations. This geometrical matching accounts for multipath components due to single-bounce as well as multiple-bounce reflections and demonstrates the high suitability and good performance of the proposed concept.