OFDM carrier frequency offset correction using zero-crossings of the inter-carrier interference based cost function

摘要

This paper introduces a carrier frequency offset (CFO) correction technique for Orthogonal Frequency Division Multiplexing (OFDM) by exploiting baseband characteristics of the Nyquist sampled received signal Fourier transform. The novelty of our algorithm is to capture the inter-carrier interference (ICI) effects using a cost function called CFO characteristic function (CF). The CFO CF is derived analytically by considering the structured nature of CFO effects. Using pilot data in an OFDM frame, we convert the matrix relation capturing the ICI effects in the OFDM signal to a functional representation of CFO. By finding numerically the root of this function, the CFO is estimated and consequently canceled. The computational complexity of the proposed receiver is significantly reduced by working with efficient numerical methods for root estimation. Robustness of the proposed ICI reduction is demonstrated at the expense of an increased computational complexity at the receiver, making this scheme attractive in practical communication systems.