Signaling method in an OFDM multiple access system

• US 9,426,012 B2
• Filed: 09/14/2012
• Issued: 08/23/2016
• Est. Priority Date: 09/13/2000
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Laroia, Rajiv, Li, Junyi, Uppala, Sathyadev Venkata
• Primary Examiner(s): NGUYEN, STEVEN H D
• Application Number:
  US13/619,460
• Publication Number:
  US 20130016678A1
• Time in Patent Office: 1,439 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H04L 27/2602 Signal structure
• CPC Class Codes: H04L 27/26025 Numerology, i.e. varying one or more of symbol duration, subcarrier spacing, Fourier transform size, sampling rate or down-clocking allocating sub-channels of the transmission path H04L5/003
• CPC Class Codes: H04L 27/2614 Peak power aspects
• CPC Class Codes: H04L 27/2636 with FFT or DFT modulators, e.g. standard single-carrier frequency-division multiple access [SC-FDMA] transmitter or DFT spread orthogonal frequency division multiplexing [DFT-SOFDM]
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/023 Multiplexing of multicarrier modulation signals multicarrier modulation H04L27/2601

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.

Claims

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; and

a third circuit configured to generate a low peak-to-average orthogonal frequency division multiplexing (OFDM) signal representing the vector of digital signal samples for transmission.

2. The processor-based apparatus of claim 1, wherein the one or more groups of tones allocated to the processor-based apparatus are contiguous.

3. The processor-based apparatus of claim 1, wherein the one or more groups of tones allocated to the processor-based apparatus comprise non-contiguous groups of tones.

4. The processor-based apparatus of claim 1, wherein the second frequency response vector is generated by inserting the zero value symbols.

5. A method for generating wireless communications by an apparatus, 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;

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; and

generating a low peak-to-average orthogonal frequency division multiplexing (OFDM) signal representing the vector of digital signal samples for transmission.

6. The method of claim 5, wherein the one or more groups of tones allocated to the apparatus are contiguous.

7. The method of claim 5, wherein the one or more groups of tones allocated to the apparatus comprise non-contiguous groups of tones.

8. The method of claim 5, wherein the second frequency response vector is generated by inserting the zero value symbols.

9. An apparatus for generating wireless communications, the 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 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; and

means for generating a low peak-to-average orthogonal frequency division multiplexing (OFDM) signal representing the vector of digital signal samples for transmission.

10. The apparatus of claim 9, wherein the one or more groups of tones allocated to the apparatus are contiguous.

11. The apparatus of claim 9, wherein the one or more groups of tones allocated to the apparatus comprise non-contiguous groups of tones.

12. The apparatus of claim 9, wherein the second frequency response vector is generated by inserting the zero value symbols.

13. The apparatus of claim 9, wherein the means for performing the DFT, the means for performing the IDFT, and the means for generating comprise a combination of hardware and software modules.

14. The apparatus of claim 9, wherein at least one of the means for performing the DFT, the means for performing the IDFT, and the means for generating comprises a hardware module.