An integer frequency offset estimator in OFDM systems

This paper investigates an improved integer frequency offset (IFO) estimator based on guard band power ratio detection (PRD) in orthogonal frequency division multiplexing (OFDM) systems, which can work with large residual fractional frequency offsets (FFOs) and therefore large inter-carrier-interference (ICIs), resulting in excellent performance in very low signal-to-noise ratio (SNR) environments. Moreover, our algorithm does not need to design the special virtual subcarrier (VSC) distributions and hence is more spectrum efficient than conventional guard band power detection (GPD) method proposed by Huang. We verify the proposed algorithm by simulations and explicitly see the significant performance improvement. Thus the improved PRD method can be concurrently operated with the FFO adjustment.