MMSE Estimation of Frequency Offset for OFDM

Abstract

In this paper, a MMSE (Minimum Mean Square Error) estimation of frequency offset for OFDM is proposed, utilizing the ICI (Inter Carrier Interference). Essentially, the ICI arises from the unorthogonality between subcarriers caused by frequency offset, which gives the chance to estimate frequency offset using ICI. To obtain the MMSE estimation of frequency offset, a linear approximation of ICI is derived. Additionally, theoretical analysis of the proposed MMSE estimator is also given. Usually, the classical estimation theory ignores the prior distribution information of parameter that is to be estimated, while in the proposed MMSE estimation, the variance of frequency offset is utilized and the variance of frequency offset can be easily obtained through the ppm (par per million) value of oscillator.