Smart Antenna Investigations for Wireless Cellular Systems

The use of smart antennas in mobile radio communications cellular networks such as GSM network, to mitigate the fading effects and to increase the traffic capacity by exploiting the Spatial Division Multiple Access (SDMA) is actually of great interest. These intelligent antenna systems take advantages of both antenna and propagation technology. Smart antennas has the capability to reduce multipath interference as modeled in Rayleigh and Rician fading channel model, increase signal to noise ratio and introduce frequency reuse within a confined environment. The convenient base station antenna is 120o sectored. Although the implementation of smart antennas is mainly investigated on base stations, due in particular to obvious cumbersomeness reasons, it is still interesting to evaluate the smart antennas performance at the mobile level. The most important feature of a smart antenna is its beam forming capability.This technique can be used to increase the coverage of a particular area or data rate or the spectral efficiency of the system. In this paper different types of techniques are used for observing the behavior of the working of smart antennas. The amplitude or time delay (phase) of the signals received by all the antennas are modified then combined in such a manner as to improve reception of the desired signal.