A novel adaptive technique for digital I/Q imbalance compensation in OFDM receivers

One of the most important impairments introduced by the analog radio frequency (RF) front-end in wireless digital communication receivers is the imbalance between the I and Q arms of a practical quadrature demodulator. In this paper we present a novel adaptive mixed time-frequency domain technique for digital I/Q imbalance compensation where the compensation is performed in the time domain while the adaptation is performed in the frequency domain. This method is suitable for orthogonal frequency division multiplexing (OFDM) receivers in the presence of carrier frequency offset (CFO) and is applied during the receiver´s normal operation without a need for an off-line calibration phase and training signals. Theoretical analysis and simulation results that prove the achievable performance and the robustness of the approach are provided.