Multiuser Transmit Beamforming via Regularized Channel Inversion: A Large System Analysis

In this paper, we analyze the performance of multiuser transmit beamforming for the broadcast channel. We focus on transmit beamforming via regularized channel inversion and our analysis is in the large system limit where both the number of users and the number of antennas approach infinity with their ratio held constant. We derive an expression for the signal-to-interference-plus-noise ratio in this large system limit. We then use this result to obtain a very simple expression for a locally optimal regularization parameter, that which maximizes the asymptotic signal-to-interference-plus-noise ratio.