Patent ID: 8649253

Claim:
A receiver for estimating a channel in an Orthogonal Frequency Division Multiple Access (OFDMA) system, the receiver comprising: a delay estimator for estimating, from a signal received from a transmitter through multipaths, at least one of an average time delay of the multipaths and a time delay of a multipath having a maximum power among the multipaths; a rotator for circular-rotating the received signal using the estimated delay before the received signal is input to a Fast Fourier Transform (FFT); and a channel estimator for estimating a channel impulse response of the circular-rotated signal, wherein the rotator quantizes the estimated average time delay and reversely circular-rotates samples of the received signal by the quantized delay, and wherein, when the received signal is rotated before being input to the FFT, the channel power of the received signal is symmetrically distributed on the basis of a time index 0 of an FFT window.