DEVICE AND METHOD FOR EFFICIENTLY PERFORMING IFFT FOR ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING (OFDM) MODULATION

摘要

A communications device includes at least one memory device (102) for storingcomplex exponential functions asapproximations of sine and cosine basis waveforms. A logic circuit (108) addsand subtracts the complex exponential functions togenerate an Orthogonal Frequency Division Multiplexed (OFDM) communicationssignal as a plurality of N data subcarriers thatcarry communications data. The logic circuit (108) provides efficient andaccurate implementation of the IFFT for use as anOFDM modulator using additions of stored complex "exponential function andmodulation of integer-valued QAM data symbolsusing logic shifts and sign changes (2's complement).