VARIABLE ERROR CORRECTION IN MULTIPOINT-TO-POINT COMMUNICATION USING ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING
First Claim
1. A multipoint-to-point, orthogonal frequency division multiplexed (OFDM) communication system comprising:
- a plurality of remote units; and
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, the tones of the upstream signals being substantially orthogonal when received at the host unit;
wherein portions of upstream OFDM signals from at least two of the remote units arrive at the host unit at the same time;
wherein the host unit demodulator demodulates said portions;
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 at least one remote unit to improve orthogonality of the OFDM waveform received at the host unit; and
wherein at least one of the remote units transmits an upstream OFDM signal to the host unit using variable error correction in which the remote unit applies at least one of a plurality of available levels of error correction.
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Accused Products
Abstract
Variable error correction for a multipoint-to-point orthogonal frequency division multiplexing (OFDM) system are provided. In one embodiment, a system comprises: a host unit; a plurality of remote units using a multiple access scheme to communicate at the same time with the host unit using 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 at least one remote unit to improve orthogonality of an OFDM waveform received at the host unit; and wherein at least one of the remote units transmits an upstream OFDM signal to the host unit using variable error correction in which the remote unit applies at least one of a plurality of available levels of error correction.
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Citations
10 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; and
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, the tones of the upstream signals being substantially orthogonal when received at the host unit;
wherein portions of upstream OFDM signals from at least two of the remote units arrive at the host unit at the same time;
wherein the host unit demodulator demodulates said portions;
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 at least one remote unit to improve orthogonality of the OFDM waveform received at the host unit; and
wherein at least one of the remote units transmits an upstream OFDM signal to the host unit using variable error correction in which the remote unit applies at least one of a plurality of available levels of error correction. - View Dependent Claims (2, 3, 4, 5)
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6. A multipoint-to-point, orthogonal frequency division multiplexed (OFDM) communication system comprising:
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a plurality of remote units; and
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, the tones of the upstream signals being substantially orthogonal when received at the host unit;
wherein portions of upstream OFDM signals from at least two of the remote units arrive at the host unit at the same time;
wherein the host unit demodulator demodulates said portions;
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 at least one remote unit to improve orthogonality of the OFDM waveform received at the host unit; and
wherein at least two different orthogonal tones used simultaneously within the OFDM communication system carry upstream signals having different levels of error correction.
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7. A system comprising:
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a host unit;
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 at least one remote unit to improve orthogonality of an OFDM waveform received at the host unit; and
wherein at least one of the remote units transmits an upstream OFDM signal to the host unit using variable error correction in which the remote unit applies at least one of a plurality of available levels of error correction. - View Dependent Claims (8, 9, 10)
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Specification