Optimal Pilot Based Frequency-Dependent I/Q Imbalance Compensation for Wideband Direct-Conversion Transmitters
Current trends in low-cost and low power consumption transmitters in state-of-the-art wireless systems is to use the direct-conversion principle. Such transmitters, however, suffer severely from the I/Q imbalance effect, which introduces mirror-frequency interference and degrades data detection. This paper proposes a novel method for frequency-dependent I/Q imbalance estimation and compensation. The I/Q imbalance is estimated jointly in the frequency domain with very low complexity and minimum error variance, by relying on a specially designed pilot and its optimization. The performance and complexity of the algorithm are evaluated through both theoretical analysis and computer simulations.