APPARATUS FOR FFT AND IFFT IN COMMUNICATION SYSTEM USING ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING AND METHOD THEREOF

摘要

An adaptive fast fourier transform and inverse transform apparatus and a method therefor in a communication system of orthogonal frequency division multiplexing are provided to efficiently compensate a channel distortion due to speed of a terminal by adaptively changing the number of points for an IFFT(Inverse Fast Fourier Transform) based on the kind of service and an estimated channel value. A terminal(700) receives a preamble signal in a frame basis from a base station(750)(711). The terminal(700) performs a channel estimation of each sub-carrier through the received preamble signal(713). Upon completing the channel estimation, the terminal(700) transmits the estimated channel information to the base station(750)(715). The base station(750) determines the number of FFT(Fast Fourier Transform)/IFFT points using the received the estimated channel information and service information(717). The base station(750) transmits determined FFT/IFFT point information to the terminal(700)(719). The terminal(700) and the base station(750) share changed FFT/IFFT point information to perform data receiving/transmitting operation(721).