REJECTION OF TRANSMIT SIGNAL LEAKAGE IN WIRELESS COMMUNICATION DEVICE
First Claim
1. A filter circuit for a radio frequency (RF) receiver, the filter circuit comprising:
- a summer that receives an RF receive (RX) input signal having a transmit (TX) leakage signal, and subtracts a TX leakage signal estimate from the RX input signal to produce an RX output signal; and
an estimator that generates the TX leakage signal estimate based on the RX output signal and a reference signal at a carrier frequency of the TX leakage signal.
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Accused Products
Abstract
This disclosure describes techniques for reducing adverse effects of transmit signal leakage in a full-duplex, wireless communication system. The disclosure describes techniques for reducing adverse effects of second order distortion and cross-modulation distortion of transmit signal leakage from a transmitter via a duplexer. The techniques may be effective in rejecting at least a portion of a transmit leakage signal, thereby reducing or eliminating distortion. The adaptive filter may include an estimator circuit that generates a transmit leakage signal estimate. A summer subtracts the estimate from the received signal to cancel transmit leakage and produce an output signal. The estimator circuit generates the transmit leakage signal estimate based on a reference signal and feedback from the output signal. The reference signal approximates the carrier signal used to generate the transmit signal in the transmitter. The reference signal may be provided by the same oscillator used to produce the transmit carrier signal.
61 Citations
47 Claims
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1. A filter circuit for a radio frequency (RF) receiver, the filter circuit comprising:
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a summer that receives an RF receive (RX) input signal having a transmit (TX) leakage signal, and subtracts a TX leakage signal estimate from the RX input signal to produce an RX output signal; and an estimator that generates the TX leakage signal estimate based on the RX output signal and a reference signal at a carrier frequency of the TX leakage signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 23, 24)
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13. A method for filtering a transmit (TX) leakage signal from a received input signal in a radio frequency (RF) receiver, the method comprising:
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receiving an RF receive (RX) input signal having a TX leakage signal; subtracting a TX leakage signal estimate from the input signal to produce an output signal; and generating the TX leakage signal estimate based on the output signal and a reference signal at a carrier frequency of the TX leakage signal. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22)
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25. A filter circuit for a radio frequency (RF) receiver, the filter circuit comprising:
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means for receiving an RF receive (RX) input signal having a transmit (TX) leakage signal; means for subtracting a TX leakage signal estimate from the input signal to produce an output signal; and means for generating the TX leakage signal estimate based on the output signal and a reference signal at a carrier frequency of the TX leakage signal. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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37. A radio frequency (RF) receiver, the receiver comprising:
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an antenna that receives a receive (RX) input signal; an amplifier that amplifies the RX input signal; a duplexer that couples the RX input signal from the antenna to the amplifier, and passes a transmit (TX) leakage signal to the amplifier as part of the RX input signal; a summer that subtracts a TX leakage signal estimate from the RX input signal to produce an RX output signal; an estimator that generates the TX leakage signal estimate based on the RX output signal and a reference signal at a carrier frequency of the TX leakage signal; and a mixer that downconverts the RX output signal to a baseband. - View Dependent Claims (38, 39, 40, 41, 42, 43, 44, 45, 46, 47)
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Specification