Performance Estimation of Adaptive Beamforming Algorithms in Smart Antennas

Adaptive antenna also known as smart antenna is a combination of antenna array with digital signal processor. It optimizes the beam pattern of antenna array according to the changing electromagnetic environment. The two key signal processing approaches of adaptive antenna are identification of spatial signature of incoming signals and adaptive beamforming (ABF). The behavior of three different beamforming algorithms, i.e., conjugate gradient algorithm (CGA), affine projection algorithm (APA), and quasi-Newton algorithm (QNA), are analyzed in terms of their beam pattern characteristics and their convergence rate. The results obtained in the simulations show that CGA has greater null depth and has fastest convergence rate among all the three algorithms.