3D correlation function of a uniform circular array using maximum power in the direction of arrival

In this paper, we derive a closed-form expression for three-dimensional (3D) spatial fading correlation (SFC) of a uniform circular array (UCA) useful for evaluating geometry-based stochastic channel models (GBSMs). The fundamental idea of the proposed model is that the total power of the incident wave is relative to the true distribution of power and dependent on the azimuthal spread (AS) and elevation spread (ES). This generalized closed-form expression permits the presentation of ES at all levels which renders the expression helpful for examining the degree of flexibility offered by ES in 3D multi-input and multi-output (MIMO) channel modeling. To minimize the effect of mutual coupling on MIMO performance using the SFC expression, the geometry-based channel is evaluated before and after decoupling process at the mobile station (MS). Finally, the present investigations demonstrate the joint contribution of AS and ES on 3D MIMO performance under Gaussian and Student's t-distributions.