Experimental investigation of elevation angles and impacts on channel capacity in urban microcell

Three dimensional (3D) Multiple Input and Multiple Output (MIMO) is one of the most promising techniques for the 5th Generation (5G) mobile communication systems. Thus there is an urgent need for one reliable 3D MIMO channel model to research and evaluate 3D MIMO techniques. In this paper, we focus on the statistic characteristics of elevation angle in urban microcell (UMi) and propose a novel elevation angle modeling methodology. In order to capture enough 3D channel characteristics, field 3D channel measurements at 3.5 GHz with 100 MHz bandwidth are conducted in UMi scenario. Based on the existing 3D channel model frame, the proposed elevation angle model is introduced and the updated 3D channel model is used to perform channel capacity analysis. Comparisons among the updated 3D channel model, the traditional two dimensional (2D) channel model and the field 3D channel data are made. The updated 3D channel model obtains obvious capacity gain compared with 2D channel model. The proposed elevation angle model and the updated 3D channel model can optimally match the channel capacity of the real 3D channel data.