Method and apparatus for error reduction in an orthogonal modulation system
First Claim
1. A method for error reduction in a communication system comprising a plurality of communication devices and a plurality of orthogonal subcarriers, the method comprising steps of:
- determining, by a first communication device of the plurality of communication devices, an equalization function that reduces a multipath delay of the received signal;
receiving, by a second communication device of the plurality of communication devices, subcarrier suppression information;
suppressing, by the second communication device, an orthogonal subcarrier of the plurality of orthogonal subcarriers based on the received subcarrier suppression information to produce a suppressed subcarrier and a non-suppressed subcarrier;
transmitting, by the second communication device, a signal comprising at least the non-suppressed subcarrier to produce a transmitted signal;
receiving, by the first communication device, the transmitted signal to produce a received signal; and
processing, by the first communication device, the received signal based on the determined equalization function.
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Accused Products
Abstract
A method and apparatus reduces error in a communication system that includes multiple orthogonal subcarriers by suppressing a subcarrier in a transmitting communication device and by equalizing a received signal in a receiving communication device. Subcarrier suppression is based on a determination of a signal quality metric with respect to each subcarrier or is based on a determination of excessive signal power overdriving an amplifier of the receiving communication device. Equalization of the received signal is based on an equalization function that reduces a multipath delay introduced to the transmitted signal when the multipath delay exceeds a tolerable multipath delay.
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Citations
33 Claims
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1. A method for error reduction in a communication system comprising a plurality of communication devices and a plurality of orthogonal subcarriers, the method comprising steps of:
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determining, by a first communication device of the plurality of communication devices, an equalization function that reduces a multipath delay of the received signal;
receiving, by a second communication device of the plurality of communication devices, subcarrier suppression information;
suppressing, by the second communication device, an orthogonal subcarrier of the plurality of orthogonal subcarriers based on the received subcarrier suppression information to produce a suppressed subcarrier and a non-suppressed subcarrier;
transmitting, by the second communication device, a signal comprising at least the non-suppressed subcarrier to produce a transmitted signal;
receiving, by the first communication device, the transmitted signal to produce a received signal; and
processing, by the first communication device, the received signal based on the determined equalization function. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14, 15, 17, 18, 19, 20, 21, 22, 24, 25, 27, 29, 30, 31, 32, 33)
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12. A method for error reduction in a communication system comprising a plurality of orthogonal subcarriers, the method comprising steps of:
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determining a signal quality metric for each orthogonal subcarrier of the plurality of orthogonal subcarriers to produce a plurality of signal quality metrics; and
suppressing an orthogonal subcarrier of the plurality of orthogonal subcarriers based on a signal quality metric of the plurality of signal quality metrics.
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16. A method for error reduction in an orthogonal modulation communication system comprising steps of:
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determining an equalization function that is capable of reducing a multipath delay of a received signal that comprises a plurality of orthogonal subcarriers; and
reducing a delay of the received signal based on the computed equalization function.
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23. A communication device comprising:
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a receiver that receives a signal that comprises a plurality of orthogonal subcarriers;
a signal processing unit coupled to the receiver that receives the plurality of orthogonal subcarriers from the receiver, determines a signal quality metric for each subcarrier of the plurality of orthogonal subcarriers, and determines subcarrier suppression information based on the determined signal quality metrics; and
a transmitter coupled to the signal processing unit that receives the subcarrier suppression information from the signal processing unit and transmits the received subcarrier suppression information.
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26. In a communication system comprising an orthogonal modulation scheme wherein user information is modulated onto a plurality of orthogonal subcarriers, a communication device comprising:
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a receiver that receives a signal comprising subcarrier suppression information, wherein the subcarrier suppression information is based on a plurality of signal quality metrics determined for each orthogonal subcarrier of the plurality of orthogonal subcarriers;
a signal processing unit coupled to the receiver that receives the subcarrier suppression information, suppresses at least one orthogonal subcarrier of the plurality of orthogonal subcarriers based on the subcarrier suppression information to produce a suppressed orthogonal subcarrier, receives data sourced by a data source, modulates the data onto a non-suppressed orthogonal subcarrier of the plurality of orthogonal subcarriers to produce a modulated non-suppressed orthogonal subcarrier; and
a transmitter coupled to the signal processing unit that transmits the modulated non-suppressed orthogonal subcarrier.
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28. In a communication system wherein a communication channel introduces multipath delay to a transmitted signal, a communication device comprising:
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a receiver that receives a signal comprising a plurality of orthogonal subcarriers; and
a signal processing unit coupled to the receiver that determines a transfer function corresponding to the communication channel, determines an equalization function that is based on a determined communication channel transfer function and that reduces the multipath delay when the multipath delay exceeds a tolerable multipath delay, and processes the signal based on the determined equalization function.
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Specification