Hottinen, AriWichman, RistoRajan, Dinesh2007-10-312007-10-311999-09-201999-09-20A. Hottinen, R. Wichman and D. Rajan, "Soft weighted STTD for W-CDMA," 1999.https://hdl.handle.net/1911/19957Conference PaperThe transmit diversity concept adopted for teh FDD mode of the third generation WCDMA system in 3G standardization has an open-loop and a closed-loop mode. The open-loop mode applies a space-time block for two transmit antennas. The closed-loop mode has two sub-modes, which both utilize downloink measurements at terminal and subsequent feedback in controlling the phase and/or gain transmit weights in the transmit antennas in order to approximate matched beamforming. These concepts are summarized in this paper for two transmit antennas and they are compared to a <i>soft-weighted</i> transmit diversity concept, proposed here, in which the relative transmit powers of the space-time encoded signals are controlled by feedback signaling. This leasds to a robust feeback mode in which the terminal is simplified in the sense that it does not require dedicated reference/pilot symbols, or weight verification, as opposed to the current feedback modes.engFDD modesoft weighted STTDW-CDMAtransmit antennasspace-timeConference paperFDD modesoft weighted STTDW-CDMAtransmit antennasspace-time