On adaptive cancellation of IQ mismatch in OFDM receivers

Design of wireless transceivers are driven by market demands for low-power and low cost terminals. Direct conversion receivers have thus been the focus of active research in recent years, since they offer great potential for compact and low power solutions. However, most direct conversion designs suffer from gain and phase imbalances between the in-phase and quadrature paths. In this paper, two adaptive algorithms for compensation of IQ mismatch effects in OFDM systems are evaluated and compared. One technique uses the samples in the time-domain while the other uses an adaptive two-tap equalizer for each sub-channel. The results of computer simulations show that using the time-domain approach, IQ imbalance can be almost completely compensated.