Joint Estimation of IQ Parameters and Channel Response for OFDM Systems

In this paper, we develop a new algorithm to jointly estimate the channel impulse response and inphase-quadrature (IQ) imbalances for OFDM systems. The estimation algorithm is based on the expectation maximization(EM) algorithm, exploiting information from the pilot symbols and detected data symbols in a systematic fashion. To reduce the complexity of the estimation algorithm, a suboptimal scheme is also introduced. The results indicate that the proposed algorithms achieve a significant improvement in the bit error rate (BER) performance when compared with conventional data-aided algorithms.