Estimation and correction of DC offset in the presence of frequency offset
First Claim
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1. A method for estimating a DC offset in a radio frequency communication receiver, the method comprising:
- receiving a plurality of samples corresponding to a transmitted signal;
correcting each of the received samples for a carrier frequency offset using a carrier frequency offset estimate, thereby generating a plurality of corrected samples;
computing an average value of a sequence of the corrected samples corresponding to a training period of the transmitted signal, wherein the transmitted signal has a known DC component during the training period;
computing an adjustment factor reflecting an effect on the DC offset of the act of correcting for a carrier frequency offset; and
adjusting the average value using the adjustment factor, thereby generating a DC offset estimate.
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Abstract
Systems and methods for estimating and correcting a DC offset in a receiver in the presence of a carrier frequency offset. Samples corresponding to a transmitted signal are received. Each sample is corrected for a carrier frequency offset. An average value is computed for a training sequence of the corrected samples, where the training sequence has a known DC offset. The average value is adjusted using an adjustment factor that reflects an effect on the DC offset of the act of correcting for a carrier frequency offset, thereby generating a DC offset estimate.
21 Citations
32 Claims
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1. A method for estimating a DC offset in a radio frequency communication receiver, the method comprising:
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receiving a plurality of samples corresponding to a transmitted signal; correcting each of the received samples for a carrier frequency offset using a carrier frequency offset estimate, thereby generating a plurality of corrected samples; computing an average value of a sequence of the corrected samples corresponding to a training period of the transmitted signal, wherein the transmitted signal has a known DC component during the training period; computing an adjustment factor reflecting an effect on the DC offset of the act of correcting for a carrier frequency offset; and adjusting the average value using the adjustment factor, thereby generating a DC offset estimate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for estimating and correcting for a DC offset in a radio frequency communication receiver, comprising:
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receiving a plurality of samples corresponding to a transmitted signal; correcting each of the received samples for a DC offset using a first DC offset estimate, thereby generating a plurality of first corrected samples; correcting each of the first corrected samples for a carrier frequency offset using a carrier frequency offset estimate, thereby generating a plurality of second corrected samples; computing an average value of a sequence of the second corrected samples corresponding to a training period of the transmitted signal, wherein the transmitted signal has a known DC component during the training period; computing an adjustment factor reflecting an effect on the DC offset of the act of correcting for a carrier frequency offset; adjusting the average value using the adjustment factor, thereby generating a residual DC offset estimate; and updating the first DC offset estimate using the residual DC offset estimate. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. In a receiver for a radio frequency communication system, a DC offset compensation circuit comprising:
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a first subtraction circuit configured to subtract a stored DC offset value from a received signal, thereby producing a first corrected signal; a phase correction circuit configured to compute a phase correction factor from a carrier frequency offset estimate; a first multiplier circuit configured to multiply the first corrected signal by the phase correction factor, thereby producing a second corrected signal; an averaging circuit configured to compute an average value of the second corrected signal over a time interval corresponding to a training period of a transmitted signal, thereby generating an average signal value, wherein the transmitted signal has a known DC component during the training period; an adjustment circuit configured to compute an adjustment factor reflecting an effect of the first multiplier circuit on the DC offset and to adjust the average signal value using the adjustment factor; and an updating circuit configured to update the stored DC offset value using the adjusted average signal value. - View Dependent Claims (21, 22, 23, 24, 25, 26)
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27. A receiver for an RF communication system, the receiver comprising:
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an analog RF module configured to receive a signal and remove an RF carrier, thereby generating a baseband analog signal; an analog-to-digital converter coupled to the analog RF module and configured to convert the baseband analog signal to a digital signal; a carrier frequency offset estimation module coupled to receive the digital signal and configured to generate a carrier frequency offset estimate; a DC offset compensation module configured to correct the received digital signal for a DC offset estimate; and a signal reconstruction module coupled to receive the corrected digital signal and configured to reconstruct a transmitted signal, the DC offset compensation module being further configured to compute the DC offset estimate by correcting the received digital signal for a carrier frequency offset using the carrier frequency offset estimate, averaging corrected signals corresponding to a training period of a transmitted signal, wherein the transmitted signal has a known DC component during the training period, and adjusting the averaged signal using an adjustment factor reflecting an effect on the DC offset of correcting the received digital signal for a carrier frequency offset. - View Dependent Claims (28, 29, 30, 31, 32)
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Specification