Performance of MRC and ZF Receivers in IQ-Impaired Uplink Massive MIMO Systems

In this paper, we consider the impact of IQ imbalance (IQI) on the achievable information rate of low complexity linear multi-user receivers in IQ-impaired uplink massive multiple-input multiple-output systems. For linear receivers with least-squares channel estimation at the base station (BS), we derive an expression for the achievable information rate of each user equipment (UE). Through simulations, we show that with a sufficiently large antenna array at the BS, no IQI compensation is required, i.e., for a desired information sum-rate the required transmit power from each UE in the presence of IQI and that without IQI (ideal scenario) are roughly the same. This greatly simplifies the receiver design and reduces its complexity.