SYNCHRONIZED MULTIPOINT-TO-POINT COMMUNICATION USING ORTHOGONAL FREQUENCY DIVISION
First Claim
1. A multipoint-to-point, orthogonal frequency division multiplexed (OFDM) communication system comprising:
- a plurality of remote units;
a host unit that includes a demodulator;
wherein 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;
wherein the host unit receives the upstream OFDM signals from a plurality of the remote units;
wherein portions of upstream OFDM signals from at least two of the plurality of remote units arrive at the host unit at the same time;
wherein the host unit demodulator demodulates said portions; and
wherein the upstream signals from the plurality of remote units arrive at the host unit synchronized in time and frequency within the OFDM waveform.
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Accused Products
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.
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Citations
15 Claims
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1. A multipoint-to-point, orthogonal frequency division multiplexed (OFDM) communication system comprising:
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a plurality of remote units;
a host unit that includes a demodulator;
wherein 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;
wherein the host unit receives the upstream OFDM signals from a plurality of the remote units;
wherein portions of upstream OFDM signals from at least two of the plurality of remote units arrive at the host unit at the same time;
wherein the host unit demodulator demodulates said portions; and
wherein the upstream signals from the plurality of remote units arrive at the host unit synchronized in time and frequency within the OFDM waveform. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for an orthogonal frequency division multiplexed (OFDM) multipoint-to-point communications system, the method comprising:
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transmitting from a host unit to at least one of a plurality of remote units an adjustment signal to assist in synchronizing upstream signals received at the host unit from the at least one remote unit; and
simultaneously receiving at the host unit over a wireless distribution network a plurality of orthogonal frequency division multiplexed upstream signals, the simultaneously received upstream signals being transmitted from a plurality of the remote units, each of the plurality of upstream signals being synchronized in time and frequency to assist in making the upstream signals orthogonal to the upstream signals of each other remote unit when received at the host unit.
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8. A multipoint-to-point, orthogonal frequency division multiplexed (OFDM) communication system comprising:
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a plurality of remote units;
a host unit that includes a demodulator;
wherein 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;
wherein the host unit allocates to each remote unit only a subset of the plurality of orthogonal tones within the OFDM waveform;
wherein the host unit receives the upstream OFDM signals from a plurality of the remote units; and
wherein modulation and transmission of the upstream OFDM signals from the plurality of remote units are synchronized in time and frequency by the host unit to be substantially orthogonal at the host unit to the upstream OFDM signals from each other remote unit. - View Dependent Claims (9, 10, 11, 12)
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13. A multipoint-to-point, orthogonal frequency division multiplexed (OFDM) communication system comprising:
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at least one host unit including a multicarrier demodulator that simultaneously demodulates upstream information modulated on a plurality of orthogonal tones, and a plurality of remote units that transmit upstream information to the host unit, each remote unit including a multicarrier modulator, the remote units synchronously transmitting in time and frequency upstream information so that when received at the host unit the tones are orthogonal within the OFDM communications system. - View Dependent Claims (14, 15)
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Specification