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.
Claims32
An apparatus for generating a vector of digital signal samples (S), the apparatus comprising:
- a processor;
- and
- a memory coupled to the processor, the memory including a set of instructions stored therein and executable by the processor to
- receive a discrete signal of complex data symbols (C), calculate frequency responses (A1, . . . AM) corresponding to tones (f(1), . . . f(M), though an M-point DFT, and output a vector of length M;
- expand the vector to a new vector of length N, and insert zero-value symbols corresponding to tones other than tones allocated to a transmitter;
- and
- perform an N-point inverse discrete Fourier transform operation on the new vector after zero insertion to obtain the vector of digital signal samples (S), and generate a low peak-to-average OFDM-based signal using the vector of digital signal samples (S) for transmission.
An apparatus for generating a vector of digital signal samples (S), the apparatus comprising:
- a processor and
- at least one hardware module coupled to the processor and configured to
- receive a discrete signal of complex data symbols (C), calculate frequency responses (A1, . . . AM) corresponding to tones (f(1), . . . f(M), through an M-point DFT, and output a vector of length M;
- p1 expand the vector to a new vector of length N, and insert zero-value symbols corresponding to tones other than tones allocated to a transmitter;
- and
- perform an N-point inverse discrete Fourier transform operation on the new vector after zero insertion to obtain the vector of digital signal samples (S), and generate a low peak-to-average OFDM-based signal using the vector of digital signal samples (S) for transmission.
Dependencies are inferred from the claim text.