A Novel Adaptive Calibration Scheme for Frequency-Selective I/Q Imbalance in Broadband Direct-Conversion Transmitters

This brief proposes a novel adaptive calibration scheme for frequency-selective I/Q imbalance in broadband direct-conversion transmitters (Tx) with multiband multistandard capability. The calibration consists of pilot-based initial calibration, followed by pilot-free parameter tracking against time-variant characteristics. Compared to the state-of-the-art (SoA) schemes, the proposed scheme has much lower complexity. Furthermore, the pilot-free tracking can provide good performance independently from the communication signal characteristic and avoids the ill-conditioned matrix problem in the SoA schemes. Its performance is verified by both computer simulations and hardware-in-the-loop experiments.