Method and apparatus for reducing a peak-to-average power ratio in an orthogonal frequency division multiplex signal
First Claim
1. A method for reducing a peak-to-average power ratio (PAPR) in an orthogonal frequency division multiplex (OFDM) signal, the method comprising:
- reordering a plurality of elements of an original frequency-domain input vector in a predetermined manner to create a plurality of candidate input vectors;
performing an inverse Fourier transform on said plurality of candidate input vectors to obtain a corresponding plurality of approximating OFDM outputs;
comparing samples of each of said plurality of approximating OFDM outputs with corresponding samples of a target output signal having an acceptably low PAPR; and
choosing, responsive to said comparing said samples, a desired output signal from said plurality of approximating OFDM outputs, said desired output signal corresponding to a next OFDM transmit symbol.
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Accused Products
Abstract
An apparatus and method therein for reducing a PAPR in an OFDM signal includes: a reorderer (104) that reorders (706) a plurality of elements of an original frequency-domain input vector in a predetermined manner to create a plurality of candidate input vectors; a Fourier processor (108) that performs (708) an inverse Fourier transform on the candidate input vectors to obtain a corresponding plurality of approximating OFDM outputs; a comparator (114) that compares (710) samples of each of the approximating OFDM outputs with corresponding samples of a target output signal; and an output selector (110) that chooses (712) a desired output signal from the approximating OFDM outputs, in response to a comparison of the samples.
81 Citations
24 Claims
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1. A method for reducing a peak-to-average power ratio (PAPR) in an orthogonal frequency division multiplex (OFDM) signal, the method comprising:
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reordering a plurality of elements of an original frequency-domain input vector in a predetermined manner to create a plurality of candidate input vectors;
performing an inverse Fourier transform on said plurality of candidate input vectors to obtain a corresponding plurality of approximating OFDM outputs;
comparing samples of each of said plurality of approximating OFDM outputs with corresponding samples of a target output signal having an acceptably low PAPR; and
choosing, responsive to said comparing said samples, a desired output signal from said plurality of approximating OFDM outputs, said desired output signal corresponding to a next OFDM transmit symbol. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An apparatus for reducing a peak-to-average power ratio (PAPR) in an orthogonal frequency division multiplex (OFDM) signal, the apparatus comprising:
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a target definer for defining a target output signal having predetermined properties including an acceptably low PAPR;
a reorderer arranged to apply a reordering to a plurality of elements of an original frequency-domain input vector in a predetermined manner to create a plurality of candidate input vectors;
a Fourier processor, coupled to the reorderer, programmed to perform an inverse Fourier transform on said plurality of candidate input vectors to obtain a corresponding plurality of approximating OFDM outputs;
a comparator, coupled to said target definer and coupled to said Fourier processor, for comparing samples of each of said plurality of approximating OFDM outputs with corresponding samples of said target output signal; and
an output selector, coupled to said comparator, arranged to choose a desired output signal corresponding to a next OFDM transmit symbol from said plurality of approximating OFDM outputs, in response to a comparison of said samples. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A wireless communication device arranged and constructed for reducing a peak-to-average power ratio (PAPR) in an orthogonal frequency division multiplex (OFDM) signal, the wireless communication device comprising:
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a modulator arranged to modulate an input data stream to produce an original frequency-domain input vector having a plurality of elements for in generating a corresponding next OFDM transmit symbol;
a reorderer, coupled to said modulator, arranged to apply a reordering to said plurality of elements in a predetermined manner to create a plurality of candidate input vectors;
a Fourier processor, coupled to the reorderer and programmed to perform an inverse Fourier transform on said plurality of candidate input vectors to obtain a corresponding plurality of approximating OFDM outputs;
a comparator, coupled to said Fourier processor, for comparing samples of each of said plurality of approximating OFDM outputs with corresponding samples of a target output signal having an acceptable PAPR;
an output selector, coupled to said comparator, arranged to choose a desired output signal from said plurality of approximating OFDM outputs, in response to a comparison of said samples, and a transmitter, coupled to said output selector, for transmitting said desired output signal as said next OFDM transmit symbol. - View Dependent Claims (20, 21, 22, 23, 24)
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Specification