A robust linear receiver for multi-access space-time block-coded MIMO systems based on probability-constrained optimization

Traditional multiuser receiver algorithms developed for multiple-input multiple-output (MIMO) wireless communication systems are based on the assumption that the channel state information (CSI) is precisely known at the receiver. However, in practical situations the exact CSI is never available. We address the problem of robustness of multi-access space-time block-coded MIMO systems against imperfect CSI. We propose a new linear receiver which guarantees the robustness against CSI errors with a certain selected probability. The proposed receiver has a form of a probability-constrained optimization problem, which can be simplified to a convex nonlinear programming (NLP) problem, based on the observation that the CSI mismatch is Gaussian. The later problem can be efficiently solved using standard optimization methods. Numerical simulations demonstrate the robustness of the proposed receiver against CSI errors.