A USRP-based experimental testbed for OFDM systems impaired by I/Q imbalance

In this paper, an experimental testbed for packet based OFDM systems is proposed using USRP RF front-ends. I/Q imbalance estimation and compensation algorithms are implemented at the receiver by manually injecting I/Q imbalance at the transmitter and/or at the receiver. RX I/Q imbalance compensation is implemented in the time domain while the TX I/Q imbalance compensation is implemented in the frequency domain using a two-tap equalizer for each pair of a subcarrier and its image. The experimental results show significant improvement due to I/Q imbalance compensation.