Capacity Analysis for OFDM Systems with Transceiver I/Q Imbalance

OFDM systems have gained utmost importance for wireless communications requiring ever higher data rates. The maximum data rate that can be achieved is, however, limited by the wireless communications channel as well as by hardware imperfections that can not be avoided in practice. One of the most serious hardware imperfections affecting the performance of OFDM systems is transceiver I/Q imbalance. This paper studies the maximum data rate, i.e. the capacity of OFDM systems that are impaired by transceiver I/Q imbalance of low-cost mobile terminals. Both, the downlink and the uplink case are considered. Closed-form expressions are derived for the ergodic system capacity and the outage probability considering different types of Rayleigh fading channels. Numerical examples are given to provide clear insight into the system capacity degradation due to transceiver I/Q imbalance.