Digital I/Q imbalance compensation in low-IF receivers: principles and practice

The current emphasis in radio transceiver design is on technologies suitable for integration on a single silicon chip. In order to simplify the receiver analog front-end and, thus, to enhance the receiver integrability, I/Q signal processing has received growing research interest. In practical analog implementations, the main barrier is vulnerability to amplitude and phase mismatches. We discuss the possibilities of using novel digital signal processing (DSP) techniques to unravel the I/Q imbalance effects. Two digital mismatch compensation algorithms are explored and analyzed using measured low-IF receiver front-end signals. Based on the obtained results, the studied algorithms can provide sufficient compensation performance also in practical operation environments, reinforcing the confidence in digital imbalance compensation techniques.