Multipath direction finding with subspace smoothing

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. In most wireless communications systems, directions of arrival of multipath signals need to be found for spatial selective transmission. Unfortunately, due to the coherent nature of multipath signals, it is quite di cult to nd their directions of arrival. In this paper, we will present a subspace smoothing algorithm for nding the directions of arrival of multipath signals based on the mobile terminal signals received at di erent time instances. More importantly, we will present our experimental results to demonstrate that the spatial diversity is present for slight movements of a mobile terminal and that the subspace smoothing approach is e ective in real wireless scenarios. All of the experiments were performed using the smart antenna testbed at the University of Texas at Austin.