Multibeam smart antenna systems for wireless communications

Abstract

<p>Smart antennas have emerged as one of the key technologies in wireless communications. This thesis focuses on developing algorithms and structures that can be applied to one of the most important types of smart antennas--the multibeam smart antenna--in order to improve the quality and capacity of both existing and future wireless networks. A large database, consisting of vector channel measurement data using an 8-element circular antenna array is analyzed to investigate the underlying characteristics of the multibeam smart antenna in practical propagation environments. Extensive vector channel simulations are also conducted, including the innovative work on the simulation of smart antennas in Frequency Division Duplexing (FDD) systems. Based on the data analysis and simulation results, two multibeam smart antenna algorithms, one for reception and one for transmission, are proposed. Significant performance and capacity improvements can be achieved using these two algorithms. The proposed multibeam smart antenna reception algorithm for DS-CDMA system is expected to have important application in both existing and the third generation CDMA systems, while the proposed multibeam smart antenna transmission algorithm can be used in FDD wireless networks to solve the downlink problem.</p>