Downlink Beamforming With Transmit-Side Channel Correlation: A Large System Analysis
In this paper, the authors consider a large system analysis of Regularized Channel Inversion (RCI) beamforming for MISO Broadcast Channels (BC) with transmit-side channel correlation. In the analysis, they assume that both the number of users and transmit antennas grow unbounded with a constant ratio. They also assume that the channel correlation model is separable. Under this channel condition, they are particularly interested to find the optimal regularization parameter of RCI that maximizes the Signal to Interference plus Noise Ratio (SINR). First, they derive the large system limit of the SINR of each user by applying some results on large random matrices. Then, they determine the corresponding optimal regularization parameter and show that this optimal regularization parameter is not affected by the transmit correlation.