Robust Equalizer Design for OFDM receivers in presence of Frequency Dependent IQ-Mismatch

In this work, we study the effect of frequency dependent IQ mismatch (TX and RX) for a wideband OFDM system. We develop a joint channel response and IQ mismatch estimation scheme that can implicitly take care of frequency dependent IQ mismatch occurring at both TX and RX. We also propose a modified frequency domain equalizer structure that can work with the above estimates to efficiently remove the interference from the image subcarrier during equalization. Finally, we have presented closed form analytical expressions for performance analysis of the above scheme for a Gray coded 8-PSK constellation at moderately high SNR.