This dissertation was presented to the Faculty of the Graduate School of The University of Texas at Austin in partial fulfillment of the requirements for the degree of

Ph.D. in Electrical Engineering

The proliferation of digital wireless communication services has been stimulating unprecedented demand for scarce radio spectrum. As the number of subscribers grows, spectral crowding and co-channel interference are becoming increasingly important issues. To alleviate such problems and to achieve the ambitious requirements introduced for existing and future wireless systems, attention has recently turned to spatial filtering methods using advanced antenna techniques, a.k.a. smart antennas. Smart antennas exploit the spatial dimension as a hybrid multiple access technique (space division multiple access-SDMA) for complementing FDMA, TDMA and CDMA to improve the quality and spectral efficiency of communications over wireless channels.

This dissertation develops new signal processing methods and derives upper bounds on capacity for smart antenna wireless communication systems. In particular, I study channel estimation for uplink and optimum weight vector design to maximize the downlink channel capacity. For uplink, I focus on blind multi-user channel estimation in code division multiple access wireless communication systems. For downlink, I investigate multi-transmitter broadcast systems. A multi-transmitter broadcast channel is a communication channel in which an antenna array system is transmitting to two or more receiving users. In order to optimize performance of the communications system, the optimal weight vector must be designed for each message signal that maximizes the overall channel capacity.