Measurement-Based Characterization of Non-Stationary Indoor Small-Scale Fading

In this work, we investigate small-scale fading observed in a singe-input-multiple-output indoor communication channel. We propose a framework to define the stationarity period and then we analyze the variations of small-scale fading statistics using the so-called second-order scattering fading (SOSF): (i) minimum stationarity period is 0.8 s, ii) the parameters of the SOSF distribution turn out to be following a Beta or an Extreme Value distribution, (iii) for describing the sudden changes of the statistics, we extracted probability and transition matrices, iv) angles of arrival can be described by a bi-modal Tikhonov-Von Mises distribution.