Study of Transmitter Diversity Techniques for WCDMA Systems

• Main Authors: Jui-peng Wu, 吳睿朋
• Other Authors: Ching-Tai Chiang
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/10871821034596893490

碩士 === 義守大學 === 電機工程學系碩士班 === 93 === The voice, data, internet and video applications are essential to future wireless communication systems. Therefore, advanced antennas array technology structures will be demanded for the variety of service requirements. As a cheap way to promote the system performance in wireless communications, transmit diversity technology has become indispensable in the third generation mobile communications. In the 3GPP standards, the transmit diversity is divided into the closed-loop and the open-loop schemes. The difference between them is that the antenna array at base-station for the closed-loop scheme obtains the optimum weights from the feedback channel information, and hence, to improve the performance of the whole system. For a transmit diversity system with M transmit antennas and one receive antenna over a flat Rayleigh fading channel, this thesis deduces the theoretical formula of bit error rate (BER) by the maximum ratio combining (MRC) technology. The analytic results show that the signal to noise ratio (SNR) of closed-loop transmit diversity is better than that of open-loop by about dB when both with same BER of . Moreover, though the phased-information-only feedback will reduce the equivalent array aperture gain, the reduction is no more than about dB. The results are helpful to design the transmit diversity systems. That is the main contribution of this thesis.