Abstract: Systems and methods for orthogonal frequency division multiplexing multipoint-to-point communications systems 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; receiving an address code assignment from the host unit, the address code to be used in communicating with the host unit, wherein the address code is unique among the plurality of remote units; and 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.

Abstract: Systems for multipoint-to-point communication using orthgonal 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. The system includes 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, multiple access configuration. 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. The first remote unit is configured to receive information from the host unit to adjust a carrier power of tones transmitted by the first of remote unit, and to adjust the carrier power based on the received information from the host unit so that the tones are orthogonal when received at the host unit.

Abstract: A bidirectional communication system is provided. In one embodiment, a system comprises a host; and a plurality of remote units, wherein a plurality of tones is shared among the plurality of remote units in order to communicate with the host using orthogonal frequency division multiplexing, wherein the plurality of tones is shared in a manner that permits at least two of the remote units to transmit to the host at any one time using the plurality of tones. The host causes at least one remote unit to adjust a timing of symbols transmitted on at least one of the plurality of orthogonal tones in order to improve an alignment of multiframes received at the host.

Abstract: A system is provided. The system includes a host and a plurality of remote units. Upstream bandwidth capacity is shared among a plurality of remote units in a manner that permits at least two of the remote units to transmit to the host at any one time using the upstream bandwidth capacity. The upstream bandwidth capacity includes a plurality of orthogonal tones generated using inverse fast Fourier transforms. The host causes at least one remote unit to adjust the manner in which symbols are transmitted therefrom on at least one of the plurality of orthogonal tones in order to improve the alignment of symbols received at the host.

Abstract: Systems for tone allocation are provided. In one embodiment, a system comprises: a plurality of remote units and a host including a demodulator. Each remote transmits an upstream OFDM signal using a multiple access scheme to the host using an OFDM waveform. The host receives the upstream OFDM signals, the tones of the upstream signals substantially orthogonal when received at the host. Portions of upstream OFDM signals from at least two remotes arrive at the host at the same time. The host demodulates said portions. At least one remote transmits to the host using a first tone allocated by the host. The host sends an adjustment signal to the remote to adjust the timing of transmissions to improve orthogonality of the OFDM waveform. After the remote has begun transmission using the first tone but before the remote has completed its transmission, the host allocates to the remote a different tone.

Abstract: Methods for multiframe alignment are provided. In one embodiment, a method comprises sharing upstream bandwidth capacity among a plurality of remote units in a manner that permits at least two of the remote units to transmit to a host at any one time using the upstream bandwidth capacity, the upstream bandwidth capacity provided by using orthogonal frequency division multiplexing with a plurality of tones; and causing at least one remote unit to adjust the timing of transmissions transmitted on at least one of the plurality of tones in order to improve alignment of multiframes received at the host.

Abstract: A method for maintaining the quality of transmission from a head end to a service unit in a telecommunications system that uses a multi-carrier transmission scheme with dynamic bandwidth allocation is disclosed. The method involves allocating a first payload channel to a service unit in a subband of a transmission channel of the telecommunications system and monitoring the quality of the first payload channel. When the quality of the first payload channel drops below a threshold, the method allocates a second, different payload channel to the channel unit.

Abstract: A multipoint-to-point, orthogonal frequency division multiplexed (OFDM) communication system is provided. The system includes a plurality of remote units and a host unit that includes a demodulator. Each of the remote units transmits an upstream OFDM signal using a multiple access scheme to the host unit demodulator using at least one of a plurality of orthogonal tones within an OFDM waveform. The host unit receives the upstream OFDM signals from a plurality of the remote units. Portions of upstream OFDM signals from at least two of the remote units arrive at the host unit at the same time. The host unit demodulator demodulates the portions and the upstream signals from the plurality of remote units arrive at the host unit synchronized in time and frequency within the OFDM waveform.

Abstract: A bidirectional communication system is provided. The system includes a first remote unit for communicating with a host unit using orthogonal frequency division multiplexing. The host unit is communicatively coupled to a plurality of remote units in a multipoint-to-point configuration. The first remote unit is configured to transmit up to a plurality of tones and the first remote unit includes a modulator for modulating the plurality of tones with upstream information using orthogonal frequency division multiplexing 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 tones are substantially orthogonal when received at the host unit.

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: A bi-directional communication system is provided. The system includes 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. A first remote unit of the plurality of remote units is configured to transmit upstream information to the multipoint-to-point host unit using one or more tones within the orthogonal frequency division multiplexing waveform. The first remote unit of the plurality of remote units is configured to detect a potential collision on one or more tones transmitted from the first remote unit and signals transmitted on one or more of the same tones within the orthogonal frequency division multiplexing waveform by another remote unit of the plurality of remote units.

Abstract: A bidirectional communication system is 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 using orthogonal frequency division multiplexing; and adjusting a round trip path delay associated with the first remote unit.

Abstract: A bidirectional communication system is provided. The system includes a first remote unit for communicating with a host unit using orthogonal frequency division multiplexing. The host unit is communicatively coupled to a plurality of remote units in a multipoint-to-point configuration. The first remote unit is configured to transmit up to a plurality of tones and the first remote unit includes a modulator for modulating the plurality of tones with upstream information using orthogonal frequency division multiplexing 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 tones are substantially orthogonal when received at the host unit.

Abstract: A method for an orthogonal frequency division multiplexing multipoint-to-point communications system is provided. The method includes 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 and 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 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 tones are substantially orthogonal when received at the host unit.

Abstract: A multiple access method for a remote unit of a multi-point to point communication system is provided. The method includes modulating one or more tones of an orthogonal frequency division multiplexing waveform with the upstream information based on an inverse Fourier transform algorithm, transmitting the one or more tones to a multi-point-to-point host unit, detecting a collision of the one or more tones, and when a collision is detected, re-transmitting the one or more tones.

Abstract: A method for an orthogonal frequency division multiplexing multipoint-to-point communications system is provided. The method includes 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, receiving information from the host unit to adjust a carrier frequency of tones transmitted by the first of remote unit, and adjusting the carrier frequency based on the received information from the host unit.