Capacity of Generalized UTRA FDD Closed-Loop Transmit Diversity Modes

JYRI HÄMÄLÄINEN, RISTO WICHMAN, ALEXIS DOUWHUSZKO, GRACIELA CORRAL-BRIONES

WIRELESS PERSONAL COMMUNICATIONS

Springer Netherlands

Año: 2009 p. 1 - 1

0929-6212

nbsp; Transmit diversity techniques have received a lot of attention recently, and open-loop and closed-loop downlink transmit diversity modes for two transmit antennae have been included into universal terrestrial radio access (UTRA) frequency division duplex (FDD) specification. Closed-loop modes provide larger system capacity than open-loop modes, but they need additional side information of the downlink channel in the trans-mitter. In FDD systems this requires a separate feedback channel. Quantization of channel state information (CSI) in closed-loop transmit diversity schemes decreases the performance when compared to a closed-loop system where the transmitter has access to complete CSI. Inthis paper, we analyze the effect of quantization of CSI and deduce approximate capacity formulae for closed-loop transmit diversity schemes that are generalizations of the closed-loopschemes included in UTRA FDD specification. Moreover, we calculate approximation error