Research On MIMO Space Fading Correlation

The main focus of this research is to investigate the spatial fading correlation of multiple-input and multiple-output (MIMO) antenna arrays systems including spatial correlation model for clustered MIMO and the effects of the spatial fading correlation on the performance of MIMO antenna system with optimum combining. Firstly, some average capacities of several typical systems, such as SISO, MISO, SIMO, MIMO, are theoretically analyzed. Then two kinds of correlation equations for MIMIO system are proposed, which are based on Gaussian angle distribution and Uniform angle distribution. Using mathematical analysis and the modified Bessel functions, the two complex models are simplified. Numerical simulations show that approximate analysis can replace the exact analysis in some cases and reduce the calculation complexity. An approximate spatial correlation model for clustered multiple-input multiple-output channels is proposed, which is for uniform linear and circular arrays to avoid numerical integrals. A new performance metric to compare parametric and nonparametric channel models is proposed and used to show that the proposed model is a good fit to the existing parametric models for low angle spreads. The proposed method is a numerically efficient way of generating the spatially correlated MIMO channels. Finally, we investigate the effects of the spatial fading correlation on the performance of a MIMO adaptive antenna system with optimum combining. We derive the closed-form formulas for the probability density function and outage probability of the maximum output SIR and the average output SIR in an interference-limited MIMO-OC system. According simulation, for given normalized threshold, increasing the number of receive antennas implies a better outage performance in the MIMO-OC system, when increasing the number of transmit antennas implies a degradation of performance in the MIMO-OC system. The effect of the spatial correlation is negligible when the maximum correlation between pairs of antenna branches is less than 0.4.