Carrier frequency offset estimation for OFDM systems with I/Q imbalance

In orthogonal frequency division multiplexing (OFDM) communication systems, there are two main types of radio frequency front-end imperfections, i.e., carrier frequency offset and in-phase/quadrature (I/Q) imbalance, which deteriorate the demodulation performance of direct conversion receiver. In this paper, a new frequency offset estimation algorithm using preambles specified in IEEE 802.11a is proposed considering the presence of I/Q imbalance. The new algorithm enjoys a low computational complexity and is less dependent on the amplitude imbalance and the angular error of the I and Q components. Simulation results show that the proposed algorithm is superior to some of the existing algorithms.