Analysis of propagation mechanisms based on direction-of-arrival measurements in urban environments at 2 GHz frequency range

In cellular mobile communications propagation environments are usually defined roughly by base station location, distance from the base station, and local environment around the mobile station. In this paper a rough categorization of the main propagation mechanisms was done based on the direction of arrival information of each incident wave at the mobile. Three propagation mechanisms, or classes, were specified; propagation along street canyons, propagation directly from transmitter over rooftops in a vertical plane, and other mechanisms as the third class. The first two classes correspond to propagation planes of quasi-3D-models, and the last class presents the proportion of power which quasi 3D-models cannot predict. The categorization is based on a constant elevation boundary for street canyon propagation and tracing of the transmitter´s azimuth direction with a small margin for over rooftop propagation. The study of the significance of different propagation mechanisms is based on measurements in several different city environments at 2 GHz frequency range. The measured data consist of microcell and small macrocell measurements and the distance between transmitter and receiver varies from 100 m to 550 m.