Closed loop transmit diversity techniques for WCDMA systems

In this paper, closed loop transmit diversity for WCDMA systems is investigated. Performance of RAKE receiver is analyzed and compared with that of space-time block coding based transmit diversity (STTD). It is shown that closed loop transmit diversity can provide a performance gain of 3dB over the open loop scheme in a single path fading channel, while the performance gain is less than 3dB in a multipath fading channel.