Two-dimensional channel models have been sufficiently accurate in 4th generation wireless communication (4G), but the traffic is expected to grow explosively over the next few years. More advanced channel models are needed for 5G mobile and wireless communication systems.
To meet this demand, the higher frequencies and wider bandwidths should be utilized. The analysis of radio wave propagation in the elevation domain has gained a lot of interest over the past few years. The majority of the research has focused on the macrocell environment. This motivated Antti Roivainen, Veikko Hovinen, Nuutti Tervo, Marko Sonkki and Claudio Ferreira Dias from the University of Oulu in Finland, and Juha Meinilä from Elektrobit Wireless Communications Ltd. In Oulu, Finland, to perform radio channel measurements in a microcell environment.
They concentrate on the analysis of the elevation angles of departure, and the elevation spread of departure. In order to achieve an accurate elevation resolution at the transmitter, nine antenna elements at the frequency of 2.3 GHz with linear spacing in the vertical dimension were placed in Oulu’s city centre. Transmitter antennas of 5 and 10 metres in height were used. By these, the researchers can provide more accurate elevation angle estimates for the propagated paths against the majority of the existing measurement results.
The results showed that the departure angles in the elevation domain can be modelled by the Laplacian distribution. The difference in elevation spread of departure between the line-of-sight and the non-line-of-sight propagation environment was significant.