Robust Linear Processing for Downlink Multiuser MIMO System with Imperfectly Known Channel

In practical systems, due to the time-varying radio channel, the channel state information (CSI) may not be known well at both transmitters and receivers. For most of the current multiuser multiple-input multiple-output (MIMO) schemes, they suffer a significant degression on the performance due to the mismatch between the true and estimated CSI. To alleviate the performance penalty, a robust downlink multiuser MIMO scheme is proposed in this paper by exploiting the channel mean and antenna correlation. These channel statistics are more stable than the imperfect CSI estimation in the time-varying radio channel, and they are used, in the proposed scheme, to minimize the total mean squared error under the sum power constraint. Simulation results demonstrate that the proposed scheme effectively mitigates the performance loss due to the CSI mismatch.