In the past, wireless systems were deployed using fixed antenna systems. For such systems, the antenna pattern could not be changed to react dynamically to changing traffic requirements. The application of smart antenna was proposed in cellular systems to overcome the problem of supporting a growing number of subscribers using the limited channel bandwidth [1]. Smart antenna also called software antenna since the beam direction and pattern can be controlled by software. In this thesis, first we study on differences between omni-directional and directional antennas and then we evaluate the capacity of CDMA systems according to three sector control methods: Fixed and Variable Angle and Silence sectoring. These methods can be used in smart antenna systems to dynamically assign channels to cellular users. We show how these algorithms could improve the capacity of cellular systems.
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