We have seen in Section 2.7 that the quadrature mixer amplitude and phase mismatches can severely degrade zero-IF OFDM transceiver performance by generating a complex conjugate image superimposed on the original signal. We demonstrated that the complex baseband signal including the IQ mismatch effect on the ideal signal *x*(*t*) can be expressed as

in which the ratio β/α is the ISR of the quadrature mixer, with

4.43

where Δ*G* and Δϕ are the amplitude and phase imbalances, respectively, and (.)* denotes the complex conjugate.

Let us suppose an ideal OFDM symbol not affected by the channel propagation:

4.44

where *s*_{k} are the data symbols, *k* is the subcarrier index, and *N* is the total number of subcarriers.

Applying the IQ mismatch from Equation 4.42, we obtain

4.45

In reception, after the DFT processing we obtain the impaired signal in frequency domain (Tubbax *et al*., 2003, 2004):

showing that the ideal symbols s_{k} are corrupted ...

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