| Wireless cellular communication is witnessing a rapid growth in markets, technology, and range of services. The increasing demand for capacity and quality motivates the need for new techniques to improve spectrum utilization. The use of adaptive antennas is one area that shows promise for increasing spectrum efficiency.This paper begins with an overview of the fundamentals of adaptive antennas. The correspondence between a spatial filter and the FIR filter is illustrated, and the spatial filter characteristic of adaptive antennas is investigated by DMI and LS-DRMTCMA algorithms. The discrete-time transmission model of synchronous CDMA systems with antenna arrays is also developed. The direction of arrival and time of arrival statistic for circular and elliptical vector channel model are derived, and efficient methods are give that can be used to simulate these models. The benefits of using adaptive antennas are also studied for 3G mobile radio system based on TD-SCDMA. hi this thesis, these benefits are explained theoretically and illustrated by computer simulation. Additionally, the mutual coupling characteristic of adaptive antennas is analyzed by MOM and equivalent network method, and the data model is built considering the mutual coupling of antennas arrays. The effect of mutual coupling on MUSIC algorithm is also studied, and we get a method to find the mutual coupling matrix based on MUSIC algorithm. Finally, the effects of mutual coupling and RF channel imbalances on TD-SCDMA are investigated, which will provide a reference for system design.
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