Comparisons on Performances in MIMO Systems under Different Propagation Environments

1 The purpose of this paper is to study how the different propagation environments as well as antenna configurations impact on the performances of space-time block coded (STBC) MIMO systems. Based on the geometrical differences such as one-ring model and elliptical model with different distributions of scatters, the comparisons on system performances are presented here. The impacts of the mean spread of the angle of arrival (AOA), the width of AOA and the antenna array configuration are included in the discussion. According to the geometrical models, analytical expressions of spatial cross-correlation functions are derived. The results show that the power efficiency and spectral efficiency are influenced differently by the antenna array configuration. So, thresholds of these impacts are found finally. Besides, a closed-form expression of a new upper bound of the ergodic capacity for STBC MIMO systems is also given here.