Joint Transmitter/Receiver I/Q Imbalance Compensation for Direct Conversion OFDM in Packet-Switched Multipath Environments

This correspondence presents an algorithm for compensation of I/Q imbalance for a direct-conversion packet-switched orthogonal frequency-division-multiplexing (OFDM) communications system, which accounts for transmitter I/Q imbalance, receiver I/Q imbalance, phase/frequency error, and dispersive multipath fading. The proposed estimation algorithm is then presented, which operates within the framework of existing multiuser OFDM radio standards (802.11a). It is shown that this algorithm accurately estimates and corrects transceiver I/Q imbalance on a packet-by-packet basis, all within the receiver´s digital baseband.