Systems and methods for orthogonal frequency division multiplexing
First Claim
1. 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;
a transmitter;
a processor coupled to the transmitter, wherein the processor outputs data for transmission by the transmitter, wherein the processor applies an inverse Fourier transform algorithm to the data provided to the transmitter;
a controller programmed to calculate an elapsed time value for each of the at least two of a plurality of remote units, the elapsed time value representing an elapsed time between transmitting a ranging signal to a remote unit and receiving a signal from the remote unit in response to the ranging signal;
the controller further programmed to reducing any difference between at least two elapsed time values by instructing at least one of the plurality of remote units to adjust a delay.
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Abstract
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 spectrally overlapping carrier signals from at least two of a plurality of remotes, wherein the 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 by the transmitter, wherein the processor applies an inverse Fourier transform algorithm to the data provided to the transmitter; a controller programmed to calculate an elapsed time for each of the two remotes, the elapsed time representing a time between transmitting a ranging signal to a remote and receiving a signal from the remote in response to the ranging signal; the controller further programmed to reducing any difference between at least two elapsed times by instructing at least one of the plurality of remotes to adjust a delay.
680 Citations
5 Claims
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1. A multi-carrier modem, the modem comprising:
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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 by the transmitter, wherein the processor applies an inverse Fourier transform algorithm to the data provided to the transmitter; a controller programmed to calculate an elapsed time value for each of the at least two of a plurality of remote units, the elapsed time value representing an elapsed time between transmitting a ranging signal to a remote unit and receiving a signal from the remote unit in response to the ranging signal; the controller further programmed to reducing any difference between at least two elapsed time values by instructing at least one of the plurality of remote units to adjust a delay. - View Dependent Claims (2, 3, 4, 5)
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Specification