Carrier frequency offset estimation for OFDM systems
First Claim
Patent Images
1. A system comprising:
- a receiver module that receives a signal that is modulated using coherent orthogonal frequency division multiplexing (OFDM) modulation;
a signal to noise ratio (SNR) module that communicates with said receiver module and that generates a SNR estimate based on said OFDM signal; and
an estimator module that communicates with said SNR module and that estimates a carrier frequency offset (CFO) of said OFDM signal based on said SNR estimate, wherein said SNR estimate is based on a difference between carrier frequencies of said receiver module and a remote transmitter, a number of subcarriers of said OFDM signal and a sampling period for said OFDM signal.
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Abstract
A system comprises a receiver module that receives a signal that is modulated using coherent orthogonal frequency division multiplexing (OFDM) modulation. A signal to noise ratio (SNR) module communicates with the receiver module and generates a SNR estimate based on the OFDM signal. An estimator module communicates with the SNR module and estimates carder frequency offset (CFO) based on the SNR estimate. System for orthogonal frequency division multiplexing (OFDM) signals such as frequency differential demodulation and time differential demodulation are also described.
92 Citations
53 Claims
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1. A system comprising:
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a receiver module that receives a signal that is modulated using coherent orthogonal frequency division multiplexing (OFDM) modulation; a signal to noise ratio (SNR) module that communicates with said receiver module and that generates a SNR estimate based on said OFDM signal; and an estimator module that communicates with said SNR module and that estimates a carrier frequency offset (CFO) of said OFDM signal based on said SNR estimate, wherein said SNR estimate is based on a difference between carrier frequencies of said receiver module and a remote transmitter, a number of subcarriers of said OFDM signal and a sampling period for said OFDM signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A system comprising:
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a receiver module that receives an orthogonal frequency division multiplexing (OFDM) signal that is modulated using differential OFDM modulation; a signal to noise ratio (SNR) module that communicates with said receiver module and that generates a SNR estimate based on said OFDM signal; and a carrier frequency offset (CFO) estimator module that communicates with said SNR module and that estimates a residual CFO of said OFDM signal based on said SNR estimate, wherein said SNR estimate is based on a difference between a carrier frequency of said receiver module and a carrier frequency of said remote transmitter, a number of subcarriers of said OFDM signal and a sampling period for said OFDM signal. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A system comprising:
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receiver means for receiving a signal that is modulated using coherent orthogonal frequency division multiplexing (OFDM) modulation; signal to noise ratio (SNR) estimating means that communicates with said receiver means for generating a SNR estimate based on said OFDM signal; and CFO estimating means that communicates with said SNR estimating means for estimating a carrier frequency offset (CFO) of said OFDM signal based on said SNR estimate, wherein said SNR estimate is based on a difference between a carrier frequency of said receiver means and a carrier frequency of a remote transmitter, a number of subcarriers of said OFDM signal and a sampling period for said OFDM signal. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28)
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29. A system comprising:
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receiver means for receiving an orthogonal frequency division multiplexing (OFDM) signal that is modulated using differential OFDM modulation; signal to noise ratio (SNR) estimating means that communicates with said receiver means for generating a SNR estimate based on said OFDM signal; and carrier frequency offset (CFO) estimating means that communicates with said SNR estimating means for estimating a residual CFO of said OFDM signal based on said SNR estimate, wherein said SNR estimate is based on a difference between a carrier frequency of said receiver module and a carrier frequency of a remote transmitter, a number of subcarriers of said OFDM signal and a sampling period for said OFDM signal. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36, 37, 38)
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39. A method comprising:
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receiving a signal in a receiver means for receiving that is modulated using coherent orthogonal frequency division multiplexing (OFDM) modulation; generating a SNR estimate based on said OFDM signal; and estimating a carrier frequency offset (CFO) of said OFDM signal based on said SNR estimate, wherein said SNR estimate is based on a difference between a carrier frequency of said receiver means and a carrier frequency of a remote transmitter, a number of subcarriers of said OFDM signal and a sampling period for said OFDM signal. - View Dependent Claims (40, 41, 42, 43, 44, 45)
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46. A method comprising:
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receiving an orthogonal frequency division multiplexing (OFDM) signal that is modulated using differential OFDM modulation; generating a SNR estimate based on said OFDM signal; and estimating a residual carrier frequency offset of said OFDM signal based on said SNR estimate, wherein said SNR estimate is based on a difference between a carrier frequency of a receiver means for receiving said OFDM signal and a carrier frequency of a remote transmitter, a number of subcarriers for said OFDM signal and a sampling period for said OFDM signal. - View Dependent Claims (47, 48, 49, 50, 51, 52, 53)
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Specification