Eigenvalue Statistics and Spatial Characteristics in Hotspot Areas Based on Wideband MIMO Channel Measurements

Wideband channel measurements have been performed at 5.25 GHz in hotspot areas in Beijing with a multiple- input multiple-output (MIMO) channel sounder. Based on the measured data in the indoor line-of-sight (LOS) and outdoor LOS/obstructed-line-of-sight (OLOS) scenarios, the frequency- dependent eigenvalues and average eigenvalue statistics are presented in this paper. In the indoor scenario, the probability density functions (PDFS) of the maximum and minimum eigenvalues are well fitted using the normal distribution. In the outdoor scenario, the log-normal distribution is proposed to model the pdfs of these two eigenvalues. As the indicator of spatial selectivity, the empirical cumulative distribution functions (CDFS) of condition number are obtained in two scenarios, indicating that the spatial multiplexing technique is more suitable in indoor LOS scenario than in the outdoor LOS/OLOS scenario. Additionally, the three-dimensional (3D) directional spread is calculated to illustrate the spatial dispersion of the multipath components. These information are of significance for the design and performance evaluation of MIMO communication systems employed in hotspot areas.