On the Capacity of OFDM Systems with Receiver I/Q Imbalance

OFDM systems have gained outstanding popularity for high data rate wireless communications. In practice, however, the performance of OFDM systems is often limited due to hardware impairments that result from stringent cost requirements. Receiver I/Q imbalance is known to be one of the most serious hardware impairments degrading the performance of OFDM systems. Previous work has shown that receiver I/Q imbalance may severely increase the symbol error rate depending on the characteristics of the communications channel. In this paper we investigate the maximum data rate, i.e. the capacity of OFDM systems that are impaired by receiver I/Q imbalance. We derive the system capacity analytically and consider the upper bound for a fixed channel realization as well as for Rayleigh fading channels.