IQ mismatch compensation using time domain signal processing: A practical approach

In recent times, analysis of transceiver RF front-end analog impairments and their compensation using digital signal processing techniques have drawn increasing interest. Analysis and calibration of frequency dependent and frequency independent IQ imbalance (FD-IQI & FI-IQI) are explored in this paper. In order to reduce implementation complexity, we propose sequential compensation rather than joint compensation of FD-IQI and FI-IQI. A low-complexity technique for compensation of FD-IQI in time-domain is presented. Fundamental limit on estimation accuracy of FI-IQI parameters is derived in the presence of uncompensated FD-IQI. Impact of the proposed technique on packet-error-rate (PER) performance of a IEEE 802.11g receiver is demonstrated via silicon measurements.