3-D Directional Wideband Dual-Polarized Measurement of Urban Mobile Radio Channel with Synthetic Aperture Technique

this paper we present a novel concept for spatial radio channel measurements at the base station site in urban environment. It combines RF switching and synthetic aperture technique and allows the full 3-D channel characterization. A high-resolution 2-D Unitary ESPRIT algorithm is used for estimation of azimuth and elevation angles of the incoming waves, and a high delay resolution is obtained using a wideband channel sounder with 2154 MHz carrier frequency. The used dual-polarized microstrip patch array allows the separation of horizontally and vertically polarized wave components. Spatial measurements at the base station (BS) site with a planar array are especially interesting because the directions of arrival (DOA) are more discrete from the BS point of view. A measurement campaign was carried out using three different receiver array (base station) sites in urban environment (downtown Helsinki), below, at, and above the roof-top level. The antenna heights and positions correspond well to urban macro- and microcell antenna installations of the operational networks. 20-30 transmitter (mobile) locations at ground level were measured for each site. Transmitter using an omnidirectional discone antenna was always at 1.5 m above the street level. The main goal of the measurement campaign was to improve understanding of the urban propagation mechanisms, such as the roles of 'street-canyon-' and 'over-therooftop -' propagation. The measurement campaign is described in more detail in [2