A low-cost blind estimation of I/Q imbalance in OFDM systems in the presence of CFO

The estimation of carrier frequency offset (CFO) and in-phase and quadrature-phase (I/Q) imbalance is an important issue in the study of the orthogonal frequency division multiplexing (OFDM) systems. In our recent work [6], we have proposed a blind algorithm for the estimation of CFO in the absence of I/Q imbalance. In this paper, a blind algorithm is introduced for the estimation of I/Q parameter in the presence of CFO. The proposed method does not need to know the channel and CFO value. Moreover a closed form formula for the I/Q parameter is derived and thus the algorithm has low complexity. Simulation results show that the proposed method performs very well. Combining the proposed method and our method in [6], we can solve the joint estimation problem of I/Q and CFO.