Method and apparatus for peak to average power ratio reduction for orthogonal frequency division multiplex systems
First Claim
1. A method for reducing a Peak to Average Power Ratio (PAPR) of a signal, the signal comprising a plurality of tones, the plurality of tones apportioned into a set of data tones and a set of reserved tones, the method comprising the steps of:
- modifying a signal value of at least one of the reserved tones according to a first processing method;
after the modification of the signal value of the at least one of the reserved tones, modifying a signal value of at least one of the data tones according to a second processing method to provide a modified signal; and
transmitting the modified signal to a receiver.
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Accused Products
Abstract
A multi-stage signal processing method is provided that reduces the Peak to Average Power Ratio (PAPR) of an Orthogonal Frequency Division Multiplexed (OFDM) signal without increasing the bit error rate of the system. The multi-stage processing system apportions the tones into a number of types, and processes the tones in an order and by a process consistent with their determined type. Advantageously, preprocessing of the time domain signal may be used to condition the data tones for optimal PAPR reduction during the multi-stage process.
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Citations
28 Claims
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1. A method for reducing a Peak to Average Power Ratio (PAPR) of a signal, the signal comprising a plurality of tones, the plurality of tones apportioned into a set of data tones and a set of reserved tones, the method comprising the steps of:
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modifying a signal value of at least one of the reserved tones according to a first processing method; after the modification of the signal value of the at least one of the reserved tones, modifying a signal value of at least one of the data tones according to a second processing method to provide a modified signal; and transmitting the modified signal to a receiver. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An Orthogonal Frequency Division Multiplexing (OFDM) transmitter comprising:
Peak to Average Power Ratio (PAPR) reduction circuitry comprising at least two stages, wherein a first stage of the PAPR reduction circuitry processes a first type of tones of an OFDM signal, a second stage of the PAPR reduction circuitry processes a second, different type of tones of the OFDM signal; and
wherein the first stage of processing operates on the OFDM signal prior to the second stage operating on the OFDM signal.- View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 28)
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26. A method of allocating tones in a multicarrier communication system comprising the steps of:
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designating a first set of tones as a reserved set of tones, the reserved set of tones being reserved for Peak to Average Power Ratio (PAPR) reduction; designating a second set of tones as data tone; reserving a third set of tones as restricted tones; and processing each type of tone of a received input signal by an OFDM transmitter in a different manner to provide an output signal with a desirable PAPR characteristic. - View Dependent Claims (27)
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Specification