The Coefficient of Variation as a Performance Metric of Mimo Antenna Systems Under Arbitrary Handset Orientations

Abstract

The Coefficient of Variation (CoV) is investigated, studied, and proposed as an alternative and important performance metric to describe the effects of handset orientation on the capacity of Multiple-Input-Multiple-Output (MIMO) systems. We combine 3-D simulated radiation patterns of a base station and handset and their associated scattering parameters in two anisotropic propagation environments. The capacity is evaluated as the handset rotates about the X-Y -Z axes using standard Euler's angles. The coefficient of variation is numerically derived by rotating the handset over the Euler angles (ϕ, θ, ψ) in each direction every 15 • about each axis over a full sphere where each rotation involves the creation of numerous instances of the propagation environment depending on the statistical robustness of the results sought. Three antenna array geometries operating at a frequency of 2.45 GHz are examined using two different propagation channel models (TGnB and TGnF) to verify the validity of the proposed approach. The derived results suggest that the proposed CoV is an effective and practical reasonable metric in selecting the best antenna system design, where "best" here refers to the design with the ability to reach the highest throughput of the designs considered.