A New Self-Calibration Method for Transmitter and Receiver Radio Impairments in Direct-Conversion Architecture

Direct-conversion radio architecture is a low-cost, small-size design for the analog front-end subsystem in a wireless communication transceiver. This architecture, however, induces radio impairments such as I-Q imbalance and dc offset that incur severe degradation in communication performance. In this paper, a new time-domain method is proposed to self-calibrate simultaneously the transmitter and receiver impairments without a dedicated analog circuit in the feedback loop. Thanks to the time-domain approach, the method is applicable to all types of systems and is able to calibrate jointly the frequency-independent I-Q imbalance, frequency-dependent I-Q imbalance, and dc offset. In addition, training sequence design is investigated to optimize the performance of calibration. Analytical and simulation results confirm the effectiveness of the proposed method.