Modulator and demodulator using dispersed pilot subchannel and ofdm frame structure in orthogonal frequency division multiplexing system

PURPOSE: A frame structure for OFDM(Orthogonal Frequency Division Multiplexing) communication system and a modulator/demodulator using dispersed pilot sub channel of the same are provided to easily equalize frame data by applying a channel estimation mode using a pilot sub channel dispersed in a data symbol. CONSTITUTION: A synchronizing symbol detects a frame starting. An OFDM symbol has a shape in which a data sub carrier wave and a pilot sub carrier wave are assigned alternately. An equalizer assigns a reference pilot signal to represent for all sub channels in a frame, extracts a phase transformed from the received OFDM symbol into the reference pilot signal of the pilot sub carrier wave, and estimates a channel of OFDM symbol through an interpolation.