Signaling method in an ofdm multiple access system
AssigneeQUALCOMM Incorporated
InventorsRajiv Laroia, Junyi Li, Sathyadev Venkata Uppala
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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.
Claims48
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 map values of the first frequency response vector to values of a second frequency response vector of length N, the second frequency response vector having zero value symbols corresponding to tones other than tones allocated to the processor-based apparatus;
- a third circuit configured to perform an N-point Inverse DFT (IDFT) on a second frequency response vector to obtain a vector of digital signal samples;
- a fourth circuit configured to pre-pend a cyclic prefix to the vector of digital signal samples;
- and
- a fifth circuit configured to generate a signal representing the vector of digital signal samples with pre-pended cyclic prefix for transmission.
A method for wireless communications utilizing at least one processor, comprising:
- performing a Discrete Fourier Transform (DFT) on a discrete signal of complex data symbols to obtain a first frequency response vector of length M;
- mapping values of the first frequency response vector to values of a second frequency response vector of length N, the second frequency response vector having zero value symbols corresponding to tones other than tones allocated to an apparatus;
- performing an N-point Inverse DFT (IDFT) on a second frequency response vector to obtain a vector of digital signal samples;
- pre-pending a cyclic prefix to the vector of digital signal samples;
- and
- generating a signal representing the vector of digital signal samples with pre-pended cyclic prefix for transmission.
A processor-based apparatus for wireless communications, the processor-based apparatus comprising:
- 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 mapping values of the first frequency response vector to values of a second frequency response vector of length N, the second frequency response vector having zero value symbols corresponding to tones other than tones allocated to the processor-based apparatus;
- means for performing an N-point Inverse DFT (IDFT) on a second frequency response vector to obtain a vector of digital signal samples;
- means for pre-pending a cyclic prefix to the vector of digital signal samples;
- and
- means for generating a signal representing the vector of digital signal samples with pre-pended cyclic prefix for transmission.
Dependencies are inferred from the claim text.