Space-Time Transmit Diversity Field Trial Using Commercial WCDMA Equipments

Space-Time Transmit Diversity (STTD) is an open-loop transmit diversity technique mandatory for WCDMA User Equipment (UE) compliant with the Release 99 of 3GPP Technical Specifications [1]. In this paper the performances of STTD are estimated through the use of link level simulations, lab tests and more importantly with an extensive field trial in which commercial WCDMA network equipments and handsets were used. The lab and field tests took place in Huawei´s research lab and trial network in Shanghai, China. The outcomes of the lab and field tests, which were fully in line with the simulation results, showed that STTD is able to offer a reduction in the NodeB transmitted code power from 1.0 dB to 3.0 dB, depending on the multipath radio channel characteristics and UE speed. The measured gains per link, translated in capacity figures, result in 40% air-interface capacity increase for a typical urban propagation environment. Therefore the results of this trial confirm that STTD is an effective feature to increase the coverage and capacity of WCDMA systems.