Systems and method for orthogonal frequency divisional multiplexing

Systems and methods for orthogonal frequency division multiplexing are provided. In one embodiment, a multi-carrier modem comprises: a receiver configured to receive a waveform comprising a plurality of spectrally overlapping carrier signals from at least two of a plurality of remote units, wherein the plurality of spectrally overlapping carrier signals are modulated using an inverse Fourier transform algorithm; a transmitter; a processor coupled to the transmitter, wherein the processor outputs data for transmission to the transmitter, wherein the processor applies an inverse Fourier transform algorithm to the data provided to the transmitter; and a controller programmed to analyze a training signal received from a first remote unit and adjust receiver equalizer parameters based on the training signal.