Experimental study of fast fading in wireless communications with a smart antenna system

Antenna arrays can be employed in mobile communications to increase channel capacity as well as communication quality via spatially selective reception/transmission at base stations. It has been demonstrated that the spatial signature of a terminal is stable enough to be estimated in uplink and then used in downlink in a smart antenna system when the terminal is stationary or moving at a very low speed. However, when the terminal is moving a relatively high speed, the Doppler effect can cause the spatial signature to change quickly. To understand better the Doppler effect in wireless communications with smart antennas, and the underlying physical model, measurement results and their analysis are given.