Interference cancellation methods and apparatus
Methods and apparatus for reducing and/or canceling signal interference between receiver and transmitter components of a wireless communications device are described. The methods and apparatus are well suited for use in a wide range of devices including user equipment devices such as cell phones as well as in network equipment such a base stations. Opto-mechanical devices are used in some embodiments as part of an apparatus which performs interference cancellation on RF (Radio Frequency) signals.
1. A method of performing radio frequency (RF) self-interference cancellation comprising:
receiving a first RF signal and a control signal;
producing an acoustic signal carrying the first RF signal;
transducing the acoustic signal onto an optical signal according to the control signal;
transducing the optical signal to an electrical signal; and
combing the electrical signal with a second RF signal to cancel interference by the first RF signal in the second RF signal.
2. The method of claim 1 , wherein transducing the acoustic signal onto an optical signal is performed via phonon-photon transduction.
3. The method of claim 2 , wherein transducing the acoustic signal onto an optical signal performed via phonon-photon transduction is controlled by the control signal comprises modifying at least one of a group consisting of:
a property of a medium through which the acoustic signal travels;
a property of a waveguide through which the acoustic signal travels;
a location of said phono-photon transduction; and
a gain of said phonon-photon transduction.
4. The method of claim 2 , wherein transducing the acoustic signal onto an optical signal performed via phonon-photon transduction is controlled by the control signal.
5. The method of claim 4 , wherein the electrical signal comprises an electrical interference cancellation signal.
6. The method of claim 5 , further comprising:
cancelling interference in the second RF signal by combining the second RF signal with the electrical interference cancellation signal.
7. The method of claim 6 , wherein combining the second RF signal with the electrical interference cancellation signal comprises adding the electrical interference cancellation signal to the second RF signal.
8. The method of claim 7 , wherein combining the second RF signal with of the electrical interference cancellation signal comprises subtracting the electrical interference cancellation signal from the second RF signal.
9. A radio frequency (RF) self-interference cancellation apparatus comprising:
a first transducer configured to receive an RF signal and to produce an acoustic signal carrying the RF signal;
a control input configured to receive a control signal for controlling phonon-photon transduction of the acoustic signal to an optical signal;
a waveguide configured to communicate the optical signal;
an optical to electrical converter configured to convert the optical signal to an electrical interference cancellation signal; and
a combiner configured to combine the electrical interference cancellation signal with the RF signal.
10. The apparatus of claim 9 , further comprising:
a heating element positioned controlled by the control signal.
11. The apparatus of claim 9 , further comprising at least one additional transducer oriented differently than the first transducer.