A Space-Time Pre-RAKE Transmitter Diversity Method for W-CDMA Using Long Range Prediction
S. Guncavdi · 2001
Transmitter diversity in the downlink for Code Division Multiple Access (CDMA) systems provides a means to achieve similar performance gains as for the mobile-station receiver diversity without the complexity of a mobile-station receiver antenna array. Pre-RAKE precoding at the transmitter can be employed to achieve the multipath diversity without the need of the RAKE receiver at the mobile station. We examine feasibility of several transmitter diversity techniques for the 3 rd generation Wideband CDMA (W-CDMA) systems. We also investigate an optimal method to combine transmitter diversity and precoding that achieves the gain of maximum ratio combining of all space and frequency diversity branches. We employ long range prediction to enable these methods for rapidly time varying multipath fading channels.