The impact of antenna directivity on the small-scale fading in indoor environments

Results obtained from using a geometrically based, single-bounce propagation model are presented to characterize small-scale fading in indoor propagation channels when directional antennas are used. The model is verified by comparing simulated results to measured results. The model is then used to obtain, via simulation, fading statistics for an indoor, line-of-sight channel. The results show that when directive antennas are used, the parameters of the Nakagami- or Rician-distributed small-scale fading vary with separation between the transmit and receive antennas. Furthermore, the strength of the variation depends on antenna directivity. Some physical mechanisms for this effect are discussed.