CHIRP Z TRANSFORM BASED OFDM SIGNAL TRANSMISSION SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide an OFDM transmission system which is applicable to both reception and transmission and improves characteristics, in order to solve the problem that in a conventional FFT system mainly used for OFDM transmission, computational complexity is too high to be used in a portable terminal and sub channels cannot be used independently, while a system using a SAW chirp filter proposed for solving the problem is applicable only to reception.;SOLUTION: According to an OFDM signal transmission system, a reception OFDM signal is converted into a TDM signal by chirp Z transform and the TDM signal is input to a post-waveform shaping filter 6. The post-waveform shaping filter removes a frequency component of a portion corresponding to a GI (Guard Interval) in the OFDM signal. In that case, the post-waveform shaping filter has nyquist characteristics, thereby remarkably reducing intersymbol interference. An OFDM transmission apparatus can also be accomplished by an inverse transform circuit of the chirp Z transformation. Thus, a mobile terminal can also be accomplished and FDM-CDMA transformation is enabled, thereby expanding the range of application.;COPYRIGHT: (C)2010,JPO&INPIT