MMSE-based IQ Imbalance Compensation for mmWave Uplink MIMO Systems

Abstract

In this paper, we investigate the impact of in-phase and quadrature-phase imbalance (IQI) on millimeter-wave (mmWave) uplink multiple-input multiple-output (MIMO) systems in which multiple users suffering IQI send their messages to a base station (BS). In order to mitigate the impact of IQI on the achievable sum rate, we propose a compensation algorithm for each user's IQI at the BS side based on the minimum mean square error (MMSE) criterion. Simulation results demonstrate that the proposed scheme achieves improved sum rate compared to the conventional zero-forcing based IQI compensation approach at the low or intermediate signal-to-noise ratio (SNR) regime. It is further shown that the proposed compensation algorithm can effectively compensate IQI under the MMSE combiner, achieving almost the same sum rate for the case of no IQI.