PURPOSE: A method for determining a training symbol, and a method and an apparatus for estimating a frequency offset in an OFDM(Orthogonal Frequency Division Multiplexing) system are provided to considerably decrease calculation quantity when estimating the frequency offset and expand the acquisition range of an offset by configuring the training symbol as a single training symbol including a protection interval in a frequency domain and estimating the frequency offset using the single training symbol. CONSTITUTION: An A/D converting unit(410) converts a received baseband analog training symbol signal into a digital training symbol signal. A protection interval removing unit(420) removes a protection interval included in the digital training symbol signal in a time domain using a detected symbol timing. An FFT(Fast Fourier Transform) unit(430) performs the FFT of the training symbol signal in which the protection interval is removed. A correlation value calculating unit(410) searches an interval in which a mean value of a plurality of successive data among the converted training symbol data is less than a predetermined threshold value, and estimates the center of a unit training symbol on the basis of the searched interval. The correlation value calculating unit(410) performs a sequential frequency transition of the unit training symbol data on the basis of the estimated center by one sample data interval unit, calculates a correlation value with a predetermined binary sequential sequence, and calculates a mean correlation value of a set uniform frequency interval per transition. An approximate frequency offset estimating unit(410) estimates a constant times frequency offset on the basis of transition degree when the calculated mean correlation value is maximum.
展开▼
