An Adaptive Rank Selection Method in 3GPP 5G NR Systems

A user equipment (UE) estimates channel state information (CSI) which includes the rank indicator (RI), the precoding matrix indicator (PMI), and the channel quality indicator (CQI), and feedbacks the CSI to the base station (BS). Rank Indicator is a number (indicator) that represents how well a Multiple Input Multiple Output (MIMO) system communication works. Therefore, the RI estimation and selection is an important issue for system efficiency. In this paper, we propose an adaptively adj usted RI selection method to accommodate the channel condition. Simulation results demonstrate that the performance of the proposed adaptive method satisfies the performance requirements of the IMT -2020 evaluation. Furthermore, the proposed adaptive method works well in a low-mobility indoor scenario.