Switched antenna transmit diversity imperfections and their implications to HSUPA performance

Abstract

3GPP is investigating uplink transmit diversity alternatives for HSUPA. This paper focuses on a transmit diversity scheme using switching between two transmit antennas without additional feedback information. The special focus of this paper is on various non-ideal conditions that occur in real implementations, such as antenna imbalance, correlation and the existence of multiple different SATD algorithms in the network simultaneously. The studies show that transmit antenna correlation somewhat decreases performance but still keeps gains over the baseline, antenna imbalance reduces situations where the switching is feasible and that using a mixture of algorithms can bring down the gains.