Compensation of Transmitter I/Q Imbalance in Millimeter-Wave SC-FDE Systems

Due to imperfect analog processing, millimeter-wave communication is confronted with severe radio frequency impairments, such as in-phase/quadrature (IQ) imbalance. The presence of I/Q imbalance introduces image interference to the desired signal and can significantly degrade the performance if not compensated. In this paper, we propose a novel training-based compensation method for transmitter (TX) I/Q imbalance in millimeter-wave single carrier with frequency domain equalization (SC-FDE) systems. The novelty of the proposed method is that it can obtain the separate estimates of the TX I/Q imbalance and multipath channel. With the obtained estimates, we can easily conduct the FDE and compensate for the TX I/Q imbalance by simple operations. Simulations show that the proposed method can accurately estimate the TX I/Q imbalance and multipath channel and, thus, can achieve almost the same performance as the ideal case free of TX I/Q imbalance.