A Dynamical Model for CSI Feedback in Mobile MIMO Systems using Dynamic Mode Decomposition

In wireless communication, it is essential for the base station (BS) to obtain the downlink channel state information (CSI). In case of the absence of channel reciprocity, the mobile station (MS) needs to report the CSI back to the BS. In mobile multiple input multiple output (MIMO) systems, the CSI feedback overhead grows proportionally with the number of antennas and with the employed bandwidth. Moreover, the channel characteristics change constantly, so the feedback must be reported repeatedly with cautiously designed update intervals depending on how rapidly the channel changes. The increasing CSI overhead becomes a performance bottleneck, therefore it is vital to reduce it while keeping the system performance as good as required. In this paper, we propose a novel method based on designing a dynamical model of a time-varying channel with help of a framework called dynamic mode decomposition (DMD). Reporting the model to the BS gives it the ability to predict the channel state and track its changes over time. Simulation results show that the proposed method can increase the interval duration between the successive feedback updates and thus reduce the average overhead.