Characterization of NLOS wireless propagation channels with a proper coherence time value in a continuous mode stirred Reverberating Chamber

The rapid growing of new wireless communication systems looks for test site able to emulate the time variability of real propagation channels for wireless device performance and signal propagation testing. The emulation of real propagation environments is very challenging because of the time varying nature of the frequency dispersiveness of the wireless propagation channels. The coherence time is the most useful parameter for describing this frequency dispersiveness in the time-domain. This paper presents a simple but effective employment of the reverberating chamber (RC) as emulator of wireless propagation channels characterized by a proper coherence time value. In particular, it is shown how it is possible to physically emulate in the RC real propagation channels with a desired coherence time value, by means of a properly tailored modulation of the stirrer velocity. The coherence time values from experimental results are used in a channel simulator and the constellation of a Global System for Mobile Communication (GSM) signal from measurements are compared to the ones obtained from the Non-Line-of-Sight (NLOS) channel simulators. A visual and a quantitative analysis shows a good agreement between measurements and simulations.