Signaling method in an OFDM multiple access system
First Claim
1. A processor-based apparatus for generating wireless communications, the processor-based apparatus comprising:
- a first circuit configured to perform a Discrete Fourier Transform (DFT) on a discrete signal of complex data symbols to obtain a first frequency response vector of length M;
a second circuit configured to perform an N-point Inverse DFT (IDFT) on a second frequency response vector of length N to obtain a vector of digital signal samples, wherein the second frequency response vector is generated from the first frequency response vector and the second frequency response vector has entries corresponding to one or more groups of tones allocated to the processor-based apparatus and zero value symbols corresponding to tones not allocated to the processor-based apparatus;
a third circuit configured to pre-pend a cyclic prefix to the vector of digital signal samples; and
a fourth circuit configured to generate an orthogonal frequency division multiplexing (OFDM) based signal representing the vector of digital signal samples for transmission.
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Abstract
A method for reducing the peak-to-average ratio in an OFDM communication signal is provided. The method includes defining a constellation having a plurality of symbols, defining a symbol duration for the OFDM communication signal, and defining a plurality of time instants in the symbol duration. A plurality of tones are allocated to a particular communication device, and a discrete signal is constructed in the time domain by mapping symbols from the constellation to the time instants. A continuous signal is generated by applying an interpolation function to the discrete signal such that the continuous signal only includes sinusoids having frequencies which are equal to the allocated tones.
899 Citations
16 Claims
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1. A processor-based apparatus for generating wireless communications, the processor-based apparatus comprising:
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a first circuit configured to perform a Discrete Fourier Transform (DFT) on a discrete signal of complex data symbols to obtain a first frequency response vector of length M; a second circuit configured to perform an N-point Inverse DFT (IDFT) on a second frequency response vector of length N to obtain a vector of digital signal samples, wherein the second frequency response vector is generated from the first frequency response vector and the second frequency response vector has entries corresponding to one or more groups of tones allocated to the processor-based apparatus and zero value symbols corresponding to tones not allocated to the processor-based apparatus; a third circuit configured to pre-pend a cyclic prefix to the vector of digital signal samples; and a fourth circuit configured to generate an orthogonal frequency division multiplexing (OFDM) based signal representing the vector of digital signal samples for transmission. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for generating wireless communications by an apparatus, comprising:
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performing a Discrete Fourier Transform (DFT) on a discrete signal of complex data symbols to obtain a first frequency response vector of length M; performing an N-point Inverse DFT (IDFT) on a second frequency response vector of length N to obtain a vector of digital signal samples, wherein the second frequency response vector is generated from the first frequency response vector and the second frequency response vector has entries corresponding to one or more groups of tones allocated to the apparatus and zero value symbols corresponding to tones not allocated to the apparatus; pre-pending a cyclic prefix to the vector of digital signal samples; and generating an orthogonal frequency division multiplexing (OFDM) based signal representing the vector of digital signal samples for transmission. - View Dependent Claims (8, 9, 10)
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11. An apparatus for generating wireless communications, the apparatus comprising:
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means for performing a Discrete Fourier Transform (DFT) on a discrete signal of complex data symbols to obtain a first frequency response vector of length M; means for performing an N-point Inverse DFT (IDFT) on a second frequency response vector of length N to obtain a vector of digital signal samples, wherein the second frequency response vector is generated from the first frequency response vector and the second frequency response vector has entries corresponding to one or more groups of tones allocated to the apparatus and zero value symbols corresponding to tones not allocated to the apparatus; means for pre-pending a cyclic prefix to the vector of digital signal samples; and means for generating an orthogonal frequency division multiplexing (OFDM) based signal representing the vector of digital signal samples for transmission. - View Dependent Claims (12, 13, 14, 15, 16)
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Specification