Performance Analysis of Three Dimensional Fading Channel Model with Angle Offset

As one of the most promising techniques for the 5th Generation (5G) mobile communication systems, Three dimensional (3D) Multiple Input and Multiple Output (MIMO) has the potential of improving spectrum efficiency, but it needs further research. For 3D channel model, the elevation angle should be accurately included. Conventionally 3D channel is modeled with an assumption that the mean elevation angle of multipath is coincided with the line of sight (LOS) direction. To investigate its authenticity, we conduct extensive 3D multiple antenna field channel measurements with 100 MHz bandwidth in a typical urban microcell (UMi) scenario. The elevation angles of each multipath is extracted from the measurement data and its statistical propagation characteristics are analyzed. It is found that for LOS case, this assumption holds. However, for none line of sight (NLOS) case, there exists an elevation angle difference between the mean and the line directly connecting transmitting and receiving antenna, which is defined as elevation angle offset. The performance of the 3D channel model with the elevation angle offset is validated in terms of channel capacity comparing to the 3D channel model without angle offset. Results show that the 3D channel model with angle offset fits the real measured data better.