OFDM Modem Method Suitable For Wireless LAN System And Supporting Variable Data Rate By Allocating Variable Bits To OFDM Subcarrier

摘要

PURPOSE: An OFDM(Orthogonal Frequency Division Multiplexing) modulation/demodulation apparatus supporting a variable data speed in a wireless LAN system and a method thereof are provided, which supports a variable data speed regulated in an IEEE 802.11a. CONSTITUTION: In an OFDM(Orthogonal Frequency Division Multiplexing) modulation/demodulation apparatus capable of receiving/transmitting MPDU(MAC Protocol Data Unit) with a variable data speed, a MAC(Medium Access Control)(40) generates a signal field and a data field constituting an OFDM frame structure or receives the signal field and the data field according to an external control signal. An OFDM modulation transmitter(60) comprises an OFDM modulation controller(1) which controls each block of an OFDM modulator on the basis of information as to a data speed and a data length included in the signal field so as to generate a final OFDM symbol by being combined with a preamble constituting an OFDM frame structure formed by being extracted from a stored sequence value, after receiving the signal field and the data field from the above MAC as exchanging the first control signal with the above MAC. And an OFDM demodulation receiver(70) comprises an OFDM demodulation controller(2) controlling each block of an OFDM demodulator on the basis of information as to the data speed and the data length included in the signal field so as to transmit the signal field and the data field to the MAC and to perform an OFDM demodulation process as exchanging the second control signal with the MAC.