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Adaptive Antennas in
Wireless Systems

Jack H. Winters
AT&T Bell Laboratories
HOH L277
791 Holmdel-Keyport Road
Holmdel, NJ 07733-0400
email: jhw@research.att.com

Abstract Three major impairments in wireless systems are: multipath fading; dispersion due to frequency-selective fading; and interference between users. In this presentation we show how antenna arrays can overcome these problems and greatly increase the capacity, range, and performance of these systems. We first describe wireless communication systems and the transmission impairments. We then show how multiple antennas at the receiver and/or transmitter can be used for overcoming problems due to multipath and frequency-selective fading, as well as suppressing interfering signals to increase system capacity. Theoretical, computer simulation, and experimental results are presented, with emphasis on practical implementation in commercial indoor wireless and cellular systems, including AMPS, IS-54, IS-95, DECT, GSM, and PCS.



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