Downlink Performance Analysis of Multicell Multiuser 3D MIMO System

Three-dimensional multiple-input multiple-output (3D MIMO) is a promising technology for the future wireless communication systems, since antenna tilt angle can reduce the intercell interference. In this paper, we consider 3D MIMO downlink analysis for a multicell multiuser scenario. Zero-forcing (ZF) precoding technique is applied at BS with perfect channel state information of all users in its cell. We derive the exact analytical expressions for downlink sum rate and outage probability for the multicell multiuser 3D MIMO system. Furthermore, we study the asymptotic system performance in the high signal-to-noise ratio (SNR) and large number of antennas regimes. The relationship between tilt angle and sum rate is given. By analyzing the effects of the tilt angle and distance between users and BS on outage probability, the optimal tilt angle and distance are determined to guarantee the outage probability performance.