Robust MMSE Precoding for the MIMO Complex Gaussian Broadcast Channel

This paper addresses the design of the linear precoders and decoders of the complex Gaussian broadcast channel in which both the base station and the remote station are equipped with arrays of multiple antennas. An imperfect channel knowledge is assumed at the base station and the minimization of the sum of the mean square errors (MMSE) of the system's substreams is chosen as optimization criterion. A stochastic approach is taken to make the design robust against the channel estimation errors. The solution is based on an iterative algorithm whose convergence is guaranteed. Simulations results emphasize the benefit of the proposed design.