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 de-modulate symbols from at least one of a plurality of spectrally overlapping carrier signals; a transmitter configured to modulate symbols onto at least one of a plurality of the spectrally overlapping carrier signals; and a processor coupled to the transmitter, wherein the processor outputs data for transmission by the transmitter, wherein the processor applies an inverse Fourier transform to the data transmitted by the transmitter, the processor programmed to multiplex upstream information onto an allocated number of the plurality of spectrally overlapping carrier signals based on an allocation instruction received be the receiver.
1 . A multi-carrier modem, the modem comprising:
a receiver configured to de-modulate symbols from at least one of a plurality of spectrally overlapping carrier signals;
a transmitter configured to modulate symbols onto at least one of a plurality of the spectrally overlapping carrier signals; and
a processor coupled to the transmitter, wherein the processor outputs data for transmission by the transmitter, wherein the processor applies an inverse Fourier transform to the data transmitted by the transmitter, the processor programmed to multiplex upstream information onto an allocated number of the plurality of spectrally overlapping carrier signals based on an allocation instruction received be the receiver.
2 . The modem of claim 1 , the controller further programmed to instruct the transmitter to transmit an adjustment instruction modulated using the inverse Fourier transform to the at least one of the plurality of remote units, the adjustment instruction instructing the at least one of the plurality of remote units to vary a phase of transmissions transmitted from the at least one of the plurality of remote units.
3 . The modem of claim 1 , wherein the inverse Fourier transform is based on one of an inverse Fast Fourier Transform (FFT) and an inverse Discrete Fourier Transform (DFT).
4 . A multi-carrier modem, the modem comprising:
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; and
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 determine a number of the plurality of the spectrally overlapping carrier signals to allocate to a first remote unit based on upstream data received from the first remote unit.
5 . The multi-carrier modem of claim 4 , wherein the inverse Fourier transform algorithm is based on one of an inverse Fast Fourier Transform (FFT) algorithm and an inverse Discrete Fourier Transform (DFT) algorithm.