Abstract: Systems for multipoint-to-point communication using orthogonal frequency division multiplexing and identification codes are provided. In one embodiment, a system comprises: a host unit; and a plurality of remote units using a multiple access scheme to communicate at the same time with the host unit using orthogonal frequency division multiplexing (OFDM); wherein the host unit allocates orthogonal tones within the system to the plurality of remote units; wherein the host unit sends an adjustment signal to at least one of the remote units instructing the at least one remote unit to adjust the timing of transmissions from the remote unit to improve orthogonality of an OFDM waveform received at the host unit, and wherein the host unit associates an address code with each of the plurality of remote units for designating downstream signals to the remote units.

Abstract: A bidirectional communication system is provided. In one embodiment, a system comprises a host unit to communicate with a plurality of remote units using orthogonal frequency division multiplexing (OFDM), the plurality of remote units communicatively coupled to the host unit in a multipoint-to-point configuration; and wherein the host unit is configured to adjust a round trip path delay associated with at least one of the plurality of remote units.

Abstract: Methods and systems for tone hopping are provided. In one embodiment, a method for an orthogonal frequency division multiplexing (OFDM) multipoint-to-point communications system comprises: establishing communication between a first remote unit of a plurality of remote units and a host unit, the plurality of remote units communicatively coupled to the host unit in a multipoint-to-point configuration; transmitting up to a plurality of tones from the first remote unit modulated with upstream information using OFDM; adjusting at least one characteristic of the up to a plurality of tones such that when any tones are transmitted from the first remote unit and at least one other remote unit of the plurality of remote units, the orthogonality of the tones received at the host unit is improved; and dynamically switching modulation between tones of the up to a plurality of tones based on an error-rate history of at least one of the tones.

Abstract: Systems and methods for bidirectional communication are provided. In one embodiment, a bidirectional communication comprises a multipoint-to-point host unit and a plurality of remote units communicatively coupled to the multipoint-to-point host unit through an orthogonal frequency division multiplexing waveform. The multipoint-to-point host unit is configured to receive the orthogonal frequency division multiplexing waveform, the orthogonal frequency division multiplexing waveform comprising a plurality of tones transmitted by the plurality of remote units. The multipoint-to-point host unit is configured to allocate up to a plurality of the plurality of tones to a first remote unit of the plurality of remote units based on a characteristic of upstream information transmitted by the first remote unit.

Abstract: Systems and methods for orthogonal frequency division multiplexing are provided.

Abstract: Systems for orderwire modulation are provided. In one embodiment, a bidirectional communication system comprises a first remote unit for communicating with a host unit using orthogonal frequency division multiplexing, the host unit communicatively coupled to a plurality of remote units in a multipoint-to-point configuration; wherein the first remote unit is configured to transmit up to a plurality of tones, the up to a plurality of tones modulated with upstream information using orthogonal frequency division multiplexing; and wherein the first remote unit is configured to modulate at least one tone of the up to a plurality of tones with payload data using a first modulation scheme, and modulate at least one tone of the up to a plurality of tones with control data using a second modulation scheme, the second scheme more robust than the first modulation scheme.

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 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; a controller programmed to instruct the transmitter to transmit a predetermined identifier on at least one of the spectrally overlapping carrier signals, the predetermined identifier identifying to a first remote unit a range of the plurality of spectrally overlapping carrier signals for the first remote unit to receive control information.

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 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.

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 a plurality of spectrally overlapping carrier signals from at least two of a plurality of remotes, the carrier signals are modulated using an inverse Fourier transform; a transmitter; a processor coupled to the transmitter, the processor outputs data for transmission to the transmitter, the processor applies an inverse Fourier transform to the data provided to the transmitter; a controller programmed to instruct the transmitter to transmit timing adjustments to the at least two of the plurality of remotes, the timing adjustments instruct the at least two of the plurality of remotes to adjust transmission timing so that transmitted symbols associated with frames of a predetermined multiframe structure are received in sequence from the at least two of the plurality of remotes based on the structure.

Abstract: Systems and methods for orthogonal frequency division multiplexing are provided.

Abstract: 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; 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 encode upstream information using a forward error correction algorithm based on forward error correction parameters received by the receiver.

Abstract: Systems and methods for bidirectional communication are provided. In one embodiment, a method for aligning communications from a plurality of remote units in a multipoint-to-point orthogonal frequency division multiplexed (OFDM) communications comprises sending a first signal from a host unit to a first remote unit; receiving a second signal transmitted from the first remote unit in response to the first signal; generating at least one timing adjustment signal based at least in part on a round trip delay between the sending of the first signal and the receiving of the second signal; transmitting the timing adjustment signal to the first remote unit; wherein the timing adjustment signal instructs the first remote unit to delay OFDM transmission of data to improve alignment of multiframes at the host unit when communications are received at the host unit from the plurality of remote units.

Abstract: Methods for an orthogonal frequency division multiplexing multipoint-to-point communications system are provided. In one embodiment, a method comprises: establishing communication between a first remote unit of a plurality of remote units and a host unit, the plurality of remote units communicatively coupled to the host unit in a multipoint-to-point configuration; transmitting up to a plurality of tones from the first remote unit, the up to a plurality of tones modulated with upstream information using orthogonal frequency division multiplexing; adjusting at least one characteristic of the plurality of tones such that when any tones are transmitted from the first remote unit and at least one other remote unit of the plurality of remote units, the orthogonality of the tones when received at the host unit is improved; and dynamically switching modulation between tones of the plurality of tones to reduce the impact of using any corrupted tones.

Abstract: Methods for orderwire modulation are provided. In one embodiment, a method for an orthogonal frequency division multiplexing multipoint-to-point communications system comprises: establishing communication between a first remote unit of a plurality of remote units and a host unit, the plurality of remote units communicatively coupled to the host unit in a multipoint-to-point configuration; transmitting non-control data on up to a plurality of tones from the first remote unit using an orthogonal frequency division multiplexing (OFDM) waveform, the up to a plurality of tones modulated with the non-control data using a first modulation scheme; and transmitting control signals on up to a plurality of tones from the first remote unit using an orthogonal frequency division multiplexing (OFDM) waveform, the up to a plurality of tones modulated with the control signals using a second, more robust modulation scheme.

Abstract: Systems and methods for bidirectional communication are provided. In one embodiment, a multipoint-to-point, orthogonal frequency division multiplexed (OFDM) communication system comprises: a plurality of remote units, a host unit; wherein the host sends an adjustment signal to a remote instructing the remote to adjust the timing of transmissions from the remote to improve orthogonality of the OFDM waveform received at the host, wherein the host sends an adjustment signal to a remote instructing the remote to adjust the frequency of transmissions from the remote to improve orthogonality of the OFDM waveform received at the host, wherein payload data is transmitted between a remote and the host over a first orthogonal tone within the OFDM communication system during a first time interval, and wherein control data is transmitted between a remote and the host over the first orthogonal tone within the OFDM communication system during a second time interval.

Abstract: Systems and methods for multiframe alignment in a multipoint-to-point orthogonal frequency division multiplexing (OFDM system are provided. In one embodiment, an (OFDM) communication system comprises: a host unit; a plurality of remote units that access the host unit using an orthogonal frequency division multiple access scheme; wherein each of the remote units modulates upstream information into an OFDM signal modulated using a Fourier transform; wherein the host unit receives upstream OFDM signals from a plurality of the remote units, wherein portions of the upstream OFDM signals arrive at the host unit at the same time; and wherein the host unit causes at least one remote unit to align symbols with symbols transmitted from another remote unit based on a predefined multiframe pattern.

Abstract: Systems and methods for round-trip-delay adjustment in a multipoint-to-point orthogonal frequency division multiplexing (OFDM) system are provided. In one embodiment, a method for multipoint-to-point communication comprises: receiving at a host a plurality of upstream symbols transmitted from a plurality of remote units, the upstream symbols transmitted on a plurality of orthogonal carriers modulated using an inverse Fourier transform; and determining respective round trip path delay values associated with each of at least two of the plurality of remote units.

Abstract: Systems and methods for contention based tones in a multipoint-to-point orthogonal frequency division multiplexing system are provided. In one embodiment, a multipoint-to-point, orthogonal frequency division multiplexed (OFDM) communication system comprises: a host unit; a plurality of remote units that access the host unit using an orthogonal frequency division multiple access scheme; wherein each of the remote units modulates upstream information into an OFDM signal modulated using a Fourier transform; wherein the host unit receives upstream OFDM signals from a plurality of the remote units, wherein portions of the upstream OFDM signals arrive at the host unit at the same time; wherein a first remote unit transmits a first upstream signal to the host unit on a first orthogonal tone; and wherein the first remote unit retransmits the first upstream signal to the host unit in the event a collision occurs on the first orthogonal tone.

Abstract: A training premable in multipoint-to-point communication using orthogonal frequency division multiplexing (OFDM) is provided. In one embodiment, a system comprises a host unit and a plurality of remote units using a multiple access scheme to communicate at the same time with the host unit using OFDM. The host unit sends an adjustment signal to at least one of the remote units instructing the at least one remote unit to adjust the timing of transmissions from the remote unit to improve orthogonality of an OFDM waveform received at the host unit. The host unit allocates orthogonal tones within the OFDM waveform to the plurality of remote units. At least one remote unit transmits a training sequence in at least one upstream OFDM signal to the host unit and the host unit uses the training sequence to assist in demodulating the upstream OFDM signal of the at least one remote unit.

Abstract: Methods and systems for forward-looking tone allocation are provided. In one embodiment, a method for an orthogonal frequency division multiplexing (OFDM) multipoint-to-point communications system comprises: establishing communication between a plurality of remote units and a host unit, the remote units communicatively coupled to the host in a multipoint-to-point configuration; transmitting a plurality of tones from the remote units, such that tones from more than one remote unit are simultaneously received at the host, the tones modulated with upstream information using OFDM; adjusting at least one characteristic of at least one tone at least one remote unit, in response to adjustment commands from the host, such that the orthogonality of the simultaneously received tones is improved as received at the host unit; and dynamically switching modulation from at least a first tone of the plurality of tones to a second tone based on an error-rate history of the second tone.