Large System Analysis of the Maximum Ratio Transmission Precoding Under Imperfect Channel State Information With Hardware Impairments

It is well known that massive multi-input multi-output (MIMO) systems rely on highly accurate channel state information (CSI). Given this critical dependence, we present a general downlink model with maximum ratio transmission (MRT) precoding, applied in a realistic cellular system with multiple antenna base station (BS). We take into consideration the aggregate effect of the limited training power, the aged CSI due to user equipment (UE) mobility, and the hardware impairments all contributing to the CSI imperfection at the BS and the UE sides. We provide a tight lower bound on the achievable sum-rate assuming the BS is using MRT precoding to serve multiple single-antenna users. The asymptotic sum-rate as the number of BS antennas becomes very large is studied, and the detrimental impacts of hardware impairment and channel aging are shown.