Fast antenna-weights tracking algorithm of adaptive antenna array diversity receiver in W-CDMA reverse link

In wideband direct sequence code division multiple access (W-CDMA), employing an adaptive antenna array is a very promising technique to reduce severe multiple access interference (MAI) especially from high rate users. This paper proposes a fast and accurate two-step antenna-weight tracking algorithm incorporated in a pilot symbol-assisted coherent adaptive antenna array diversity (PSA-CAAAD) receiver and evaluates its performance both by computer simulations and laboratory experiments. In the proposed scheme, the receiver antenna weights are updated by using both an adaptive algorithm based on the minimum mean square error (MMSE) criterion and the signal-to-interference power ratio (SIR) measurements employing multiple sets of antenna weights (MSAW), in which other sets except for a master set of antenna weights are simply generated by a master set. Computer simulation results show that antenna weights of a four-antenna PSA-CAAAD receiver using the proposed beam-tracking algorithm tracks changes in the direction of arrival (DOA) of the desired user at up to 20 degrees per sec, which corresponds to 250 km/h at 200 m from a base station. We also confirm based on experiments in radio anechoic room that the generated antenna weights can track the DOA changes up to 12 degrees/sec.