Experimental Validation of the Reverberation Effect in Room Electromagnetics

Abstract

The delay power spectrum is widely used in both communication and localization communities for characterizing the temporal dispersion of the radio channel. Experimental investigations of in-room radio environments indicate that the delay power spectrum exhibits an exponentially decaying tail. This tail can be characterized with Sabine's or Eyring's reverberation models, which were initially developed in acoustics. So far, these models were only fitted to data collected from radio measurements, but no thorough validation of their prediction ability in electromagnetics has been performed yet. This paper provides a contribution to fill this gap. We follow Sabine's original experimental approach, which consists in comparing model predictions to experimental observations in a room, while varying its mean absorption coefficient and total room surface. We find that Eyring's model provides a more accurate prediction of the parameters characterizing the decaying tail, such as the reverberation time, than Sabine's model. We further use the reverberation models to predict the parameters of a recently proposed model of a distance-dependent delay power spectrum. This model enables us to predict the path loss, mean delay, and root mean square (rms) delay spread versus transmitter-receiver distance. We observe good agreement between predictions and experimental results.