Robust Algorithms for DOA Estimation and Adaptive Beamforming for Smart Antenna Application

This paper presents a tool for the modelling, analysis and simulation of direction-of-arrival (DOA) estimation and adaptive beamforming needed in the design of smart antenna arrays for wireless mobile communications. In this paper performance of adaptive beamforming algorithm has been studied for two different DOA estimation algorithms namely MUSIC & MVDR. MUSIC estimates the number of incident signals on the array and their directions of arrival. It also gives the direction of arrival of desired signal. The Minimum Variance Distortion less Response (MVDR) is a very well known algorithm to obtain the optimum weight vector, which maximizes the output signal to noise and interference ratio (SNIR) of multiple antennas. The LMS algorithm, which has been simulated, is a simple yet efficient technique for robust adaptive beamforming. The LMS algorithm recursively computes and updates the weight vector. It has been observed that LMS algorithm gives the response for the two different DOA estimation algorithms MUSIC & MVDR depending upon the DOA estimations.As the signals are randomly generated the response of LMS algorithm differ for some cases of DOA estimations using MUSIC & MVDR otherwise it gives same response for both the algorithms. The algorithms have been simulated in MATLAB 7.4 version. A simulation tool with a graphical user interface, which implements these algorithms, is developed. Results of numerical simulation are useful for the design of smart antennas systems with optimal performance.