Transmit Diversity in the WCDMA System

摘要

This document presents the transmit diveristy concept adopted for the FDD mode of the third-generation WCDMA system is ETSI in 1998. The open-loop mode is based on the space-time block code attaining full diversity order with two transmit antennas. Different feedback modes are specified. They all utilize terminal measurements in controlling the transmit weighting in the transmit antenneas. The concept is described in detail for two transmit antennas. It is shown that very limited feedback from the terminal to the base, as defined for the FDD mode, can increase downlink performance significantly when compared to single-antenna transmission.