OFDM speed estimation
First Claim
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1. A method for estimating speed using an orthogonal frequency division multiplexing (OFDM) receiver, the method comprising:
- receiving a radio frequency (RF) signal at the OFDM receiver, the OFDM receiver having a fast Fourier transform (FFT) stage;
storing a first output of the FFT stage in a memory, the first output corresponding to the RF signal at a first time;
convolving the first output with a second output of the FFT stage, the second output corresponding to the RF signal at a second time;
determining one or more observables of the convolution; and
estimating a speed based on the one or more observables.
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Abstract
Techniques are provided for deriving speed estimates by performing a convolution of the output of the Fast Fourier Transform (FFT) stage from different time windows in an orthogonal frequency-division multiplexing (OFDM) modulation scheme. Such techniques enable speed estimation to be performed in the frequency domain, requiring little or no modification to existing OFDM systems.
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Citations
24 Claims
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1. A method for estimating speed using an orthogonal frequency division multiplexing (OFDM) receiver, the method comprising:
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receiving a radio frequency (RF) signal at the OFDM receiver, the OFDM receiver having a fast Fourier transform (FFT) stage; storing a first output of the FFT stage in a memory, the first output corresponding to the RF signal at a first time; convolving the first output with a second output of the FFT stage, the second output corresponding to the RF signal at a second time; determining one or more observables of the convolution; and estimating a speed based on the one or more observables. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An orthogonal frequency division multiplexing (OFDM) receiver comprising:
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an antenna configured to receive a radio frequency (RF) signal; a fast Fourier transform (FFT) module configured to provide; a first output corresponding to the RF signal at a first time; and a second output corresponding to the RF signal at a second time; a memory, coupled with the FFT module, configured to store the first output; and a convolution module, coupled with the FFT module and the memory, configured to convolve the first output and the second output; and a speed estimation module configured to; determine one or more observables of the convolution of the first output and the second output; and estimate a speed based on one or more observables. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A device comprising:
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means for receiving a radio frequency (RF) signal at an OFDM receiver, the OFDM receiver having a fast Fourier transform (FFT) stage; means for storing a first output of the FFT stage, the first output corresponding to the RF signal at a first time; means for convolving the first output with a second output of the FFT stage, the second output corresponding to the RF signal at a second time; means for determining one or more observables of the convolution; and means for estimating a speed based on the one or more observables. - View Dependent Claims (14, 15, 16, 17, 18)
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19. A non-transitory machine-readable storage medium comprising instructions that, when executed by a processor, perform functions including:
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receiving a radio frequency (RF) signal at an OFDM receiver, the OFDM receiver having a fast Fourier transform (FFT) stage; storing a first output of the FFT stage, the first output corresponding to the RF signal at a first time; convolving the first output with a second output of the FFT stage, the second output corresponding to the RF signal at a second time; determining one or more observables of the convolution; and estimating a speed based on the one or more observables. - View Dependent Claims (20, 21, 22, 23, 24)
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Specification