Performance Gain of Smart Antennas with Hybrid Combining at Handsets for the 3GPP WCDMA System

We investigated the performances of the diversity combining and the adaptive combining schemes. Based on the results, we propose a hybrid combining for a dual smart antenna system at handsets for the 3GPP WCDMA system and present the performance of the hybrid combining scheme. The proposed hybrid combiner intends to exploit the advantages of the two combining schemes. We considered two different channel models for dual antenna signals and adopted the geometrically based single bounce (GBSB) elliptical and circular models to obtain the channel profile. The simulation results indicate that i) the adaptive combining scheme performs the best among the three combining schemes in an interference-dominant environment or for low mobile velocity, ii) the diversity combining scheme performs the best provided dual antenna signals are uncorrelated, the interference from an adjacent base station is weak, or the mobile velocity is high, and iii) the performance of the hybrid combining scheme always lies in between those of the two combining schemes.