Elevation domain channel measurement and modeling for FD-MIMO with different UE height

The full-dimensional MIMO (FD-MIMO) technology is expected to increase the system capacity significantly by elevation beamforming and sectorization, especially for the users on different floors in buildings. To design and evaluate the FD-MIMO requires the indoor-to-outdoor (I2O) channel modeling in the elevation domain, with the user equipments (UEs) located at different heights. However, such channel models are still lacking. In this paper, using a channel sounder equipped with two uniform planar antenna arrays, we have performed the spatial channel measurement in an urban micro-cell (UMi) environment where the UE is located from the 1st to the 5th floors and on each floor both LOS and NLOS scenarios are considered. The power and elevation angle of arrival (EoA) of each propagation path at the base station are estimated, and the distribution of the EoA and elevation spread of arrival (ESA) at each floor are obtained. The stochastic models of EoA and ESA with respect to the UE height are also proposed. This work can help to extend the current 2-dimensional channel models by combining the elevation propagation statistics to support the FD-MIMO system design.