Browsing by Author "Wichman, Risto"

Now showing 1 - 1 of 1
  • Thumbnail Image
    Item
    Soft weighted STTD for W-CDMA
    (1999-09-20) Hottinen, Ari; Wichman, Risto; Rajan, Dinesh; Center for Multimedia Communications (http://cmc.rice.edu/)
    The 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 soft-weighted 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.