An antenna array consists of distributed antenna elements whose outputs are combined in such a way that the parameters of communication system are optimized. A smart antenna is an antenna array system aided by some “smart” algorithms designed to adapt to different signal environments. Through beamforming, smart antennas offer low co-channel interference and large antenna gain to the desired signal, leading to better performance than conventional antenna systems. Since beamforming is performed in software, forming several beams with the same array is possible by simply reusing the array output. The signal received at each antenna element is multiplied by an optimum weight and these products are added to get the desired output signal. The weight vector can be calculated using one of the many adaptive algorithms such as Least Mean Square (LMS) algorithm, Sample Matrix Inversion (SMI) algorithm, Recursive Least Square (RLS) algorithm and their variants. The SMI algorithm has a faster convergence rate since it employs direct inversion of covariance matrix to compute the weights. This paper analyzes how weight vector and beam pattern of the smart antenna system are changing for different angles of arrival of desired signal and also for different number of antenna elements in an antenna array.

The chief goal of wireless communication research is to enhance user capacity, data rates and channel reliability. User capacity refers to the number of subscribers that can be simultaneously serviced by a wireless system. Increasing data rates allow subscribers to enjoy new services such as multimedia and broadband Internet access. Improving channel reliability can reduce symbol-error rates or reduce the chances of dropped calls. Major obstacles to these goals include channel fading, noise, interference and frequency selective distortion.

Smart antennas (Reed, 2002; and Frank, 2005) can be used to improve the quality of wireless communication systems. A smart antenna is an antenna array system aided by some “smart” algorithms designed to adapt to different signal environments. An antenna array consists of distributed antenna elements whose outputs are combined or selected and is a practical tool for enhancing wireless system performance. They mitigate fading through diversity reception and beamforming, while minimizing interference through spatial filtering. Using a single smart antenna system is not ideal for all these tasks like minimizing fading and interference, etc. So certain array designs of smart antennas are more suited for interference rejection than diversity reception and vice versa.

Telecommunications Journal, Smart antennae, Fully adaptive arrays, Adaptive algorithms, Sample Matrix Inversion (SMI) algorithm, Least Mean Square (LMS) algorithm.