Non-Recursive Channel Prediction for TDD Massive MIMO Systems

Multi-user broadcast downlink communication where the Base Station (BS) is equipped with massive array of antenna elements serving multiple users (MU-MIMO) is a key enabler for realizing increased spectral and energy efficiencies in current and future wireless communication networks. For using complexity efficient signal processing techniques and yet achieving these promising gains, the availability of highly accurate Channel State Information (CSI) at the transmitter is a must. As the mobility of the served user and/or its surrounding environment increases, the CSI present at the transmitter becomes outdated, so if it was used for downlink transmission it would cause performance degradation due to residual inter-user interference In this paper a CSI prediction method is proposed, that uses exponentially weighted current and past channel measurements to efficiently predict the future channel realizations. A closed form lower bound expression for the rate per user is provided, moreover simulation results presented show the robustness of the proposed method against model mismatch and longer channel prediction horizons in comparison with other conventional methods.