On the constrained stochastic gradient algorithm behavior in wireless communication networks

The purpose of this paper is to report on an unsuitable behavior of the constrained stochastic gradient (CSG) algorithm for adaptive beamforming in the combination of two events: one or more interference angles-of-arrival are close to the signal angle-of-arrival and the angle spreads of the involved signals are small. In this situation, the CSG algorithm stresses the co-channel interference minimization more than the maximization of the power radiated to the in-cell mobile terminal. We term this phenomenon unbalanced behavior and provide an analytical study to explain it.