Frequency Dependency Analysis of SHF Band Directional Propagation Channel in Indoor Environment

In the fifth-generation mobile communication system (5G), the millimeter wave band wireless communication is highly expected that it increases the network capacity drastically. The radio propagation characteristics in the millimeter wave band are thought to be quite different from the microwave band that has been used for the current mobile wireless communication. And it is needed to clarify those differences in a comparative way for investigating the feasibility of millimeter wave communication system in the actual environment. Author's research group has conducted channel measurements in several super high frequency (SHF) bands and investigated the frequency characteristics of the propagation channel to solve the issue. In this paper, we conducted the channel measurements in 3 GHz, 10 GHz and 28 GHz bands in a small room environment. The delay and both the azimuth and the elevation directional characteristics of the channels were investigated by using the virtual cylindrical array. The results showed that not only the reflection from walls but also the reflections from the floor and the ceiling were also significant in the early propagation delay region. The results are expected to be utilized for the system deployment of millimeter wave communication system.