Analytical BER Performance of M-QAM-OFDM Systems in the Presence of IQ Imbalance

It is well known that the performance of OFDM systems is severely affected by the inphase and quadraure (IQ) imbalances of down converter modulators in receivers. In this paper, the effects of IQ imbalance on the performance of the OFDM systems with rectangular M-QAM constellations are investigated and a closed form of bit error rate (BER) of these systems in additive white Gaussian noise (AWGN) channels is derived. Theoretical results show perfect matching with those obtained by simulations and they can be used to derive the OFDM system performance, without the need to run extensive simulations.