Statistical modeling of signal amplitude fading of indoor radio propagation channels

Small-scale and large-scale variations of signal amplitude for wideband data collected at two office buildings have been investigated. The data base includes 12000 impulse response estimates which were obtained by inverse Fourier transforming of the channel´s frequency response profiles. Extensive curve fitting for the distribution of individual multipath components´ amplitudes using elaborate tests based on the Kolmogorov-Smirnov and Wilcoxon procedures shows that amplitude fading is lognormal for both local and global data. For the local data, the lognormal, Nakagami, and Rayleigh distributions passed the Kolmogorov-Smirnov test with a 90% confidence level for 76%, 36%, and 13% of cases, respectively. For global data the Wilcoxon test showed that with 99% confidence lognormal is better than Nakagami, and with 94% confidence Nakagami fits the data better than Rayleigh. After establishing the lognormality of signal amplitude fading in these environments, a two-dimensional Gaussian distribution for simulating the log- amplitudes of spatially-adjacent profiles has been proposed and implemented.