Blind CFO Estimation in OFDM Links with IQ Imbalance

In this paper a simple blind algorithm is presented for estimation of carrier frequency offset (CFO) in OFDM links with IQ imbalance distortion that exploits the finite alphabet nature of the transmitted symbols. Most algorithms proposed to date estimate the CFO using a specially designed preamble sequence, which makes them unsuitable for use in time-varying environments. Other algorithms based on the null carriers and the cyclic prefix either place restrictions on the CFO or the channel, or result in rate reduction. The proposed algorithm requires no pilot (no rate reduction), and instead just requires (assuming oversampling is used at the receiver), the symbol on any one carrier to be M-PSK. Performance of the proposed algorithm is evaluated by computer simulations to demonstrate its effectiveness.