Experiment and Simulation Results of Adaptive Antenna Array System at Base and Mobile Stations in Mobile Environment

In a time division duplex (TDD) based adaptive array antenna (AAA)/space division multiple access (SDMA) system, the array weights determined from up-link signals can be applied to the down-link transmission because of the channel reciprocity. However, under fast fading conditions, for example due to fast moving mobile station (MS), the array weights are no longer optimum for the down-link signal transmission and hence the spectral efficiency of the system degrades in down-link. In this paper, we present the computer simulation and field experiment down-link performance of MS with two antenna elements moving at various velocities in the field trial system of i-Burst, which is a wireless broadband system employing AAA and SDMA techniques. Both the results show that adaptive antenna processing at MS is effective in improving the mobility performance of TDDAAA/SDMA system.