Systems for multi-peak-filter-based analog self-interference cancellation

1. A system for multi-peak filter-based analog self-interference cancellation comprising:

a transmit coupler, communicatively coupled to an analog transmit signal of a communication system, that samples the analog transmit signal to create a sampled analog transmit signal;

an analog self-interference canceller, comprising a first signal divider, first and second filters, first, second, and third scalers, and a first signal combiner, wherein the first signal divider splits the analog transmit signal into first, second, and third signal paths; wherein the first filter filters the first signal path and the first scaler scales the first signal path to create a first analog self-interference signal component; wherein the second filter filters the second signal path and the second scaler scales the second signal path to create a second analog self-interference signal component; wherein the third signal path is unfiltered and the third scaler scales the third signal path to create a third analog self-interference signal component; wherein the first filter has a single peak centered at a first frequency; wherein the second filter has exactly two peaks centered at a second frequency and a third frequency respectively; wherein the first frequency is twice the second frequency; wherein the third frequency is three times the second frequency; wherein the first signal combiner combines the first, second, and third analog self-interference signal components to form a first analog self-interference cancellation signal;

a receive coupler, communicatively coupled to an analog receive signal of the communication system, that combines the first analog self-interference cancellation signal with the analog receive signal.

2. The system of claim 1 , wherein the first and second filters are resonant element filters; wherein the second filter comprises two resonant elements in parallel.

3. The system of claim 2 , wherein the first and second filters are lumped element resonant element filters.

4. The system of claim 3 , wherein the first and second filters each include a tunable shunt capacitor; wherein the shunt capacitor is a varactor; wherein parameters of the varactor are controlled by a tuning circuit in response to received complex weights.

5. The system of claim 3 , wherein the first and second filters each include a tunable shunt capacitor; wherein the shunt capacitor is a digitally tunable capacitor; wherein parameters of the digitally tunable capacitor are controlled by a tuning circuit in response to received complex weights.

6. The system of claim 1 , wherein outer edges of passbands of the first filter and the second filter are at same frequencies.

7. The system of claim 1 , wherein the first signal path, associated with the first filter having a single peak, is configured to have a first delay; wherein the second signal path, associated with the second filter having two peaks, is configured to have a second delay; wherein the third signal path, associated with no filter, is configured to have a third delay; wherein a difference between the first delay and the third delay is equal to a difference between the second delay and the first delay.

8. The system of claim 7 , wherein the analog self-interference canceller further comprises a second signal divider, third and fourth filters, fourth, fifth, and sixth scalers, a second signal combiner, wherein the second signal divider splits the analog transmit signal into fourth, fifth, and sixth signal paths; wherein the third filter filters the fourth signal path and the fourth scaler scales the fourth signal path to create a fourth analog self-interference signal component; wherein the fourth filter filters the fifth signal path and the fifth scaler scales the fifth signal path to create a fifth analog self-interference signal component; wherein the sixth signal path is unfiltered and the sixth scaler scales the sixth signal path to create a sixth analog self-interference signal component; wherein the third filter has a single peak centered at the first frequency; wherein the fourth filter has exactly two peaks centered at the second frequency and the third frequency respectively; wherein the second signal combiner combines the fourth, fifth, and sixth analog self-interference signal components to form a second analog self-interference cancellation signal; wherein the receive coupler combines the first analog self-interference cancellation signal and the second analog self-interference cancellation signal with the analog receive signal.

9. The system of claim 8 , wherein the fourth signal path, associated with the third filter having a single peak, is configured to have the first delay; wherein the fifth signal path, associated with the fourth filter having two peaks, is configured to have the second delay; wherein the sixth signal path, associated with no filter, is configured to have the third delay.

10. The system of claim 9 , wherein the analog self-interference canceller further comprises a delayer, coupled to the second signal combiner, that delays the second analog self-interference cancellation signal.

11. The system of claim 10 , wherein the delayer delays the second analog self-interference cancellation signal by a post-combination delay; wherein the post-combination delay is equal to three times the difference between the first delay and the third delay, wherein addition of the post-combination delay results in formation of an arithmetic series of delays by the first, second, third, fourth, fifth, and sixth signal paths.

12. The system of claim 11 , wherein outer edges of passbands of the first, second, third, and fourth filters are at same frequencies.

13. The system of claim 11 , wherein the first scaler compensates for magnitude changes to the first signal path due to filtering by the first filter; wherein the second scaler compensates for magnitude changes to the second signal path due to filtering by the second filter; wherein the fourth scaler compensates for magnitude changes to the fourth signal path due to filtering by the third filter; wherein the fifth scaler compensates for magnitude changes to the fifth signal path due to filtering by the fourth filter.

14. The system of claim 8 , wherein the first, second, third, and fourth filters are resonant element filters; wherein the second and fourth filter comprise two resonant elements in parallel.

15. The system of claim 14 , wherein the first and third filters each include a tunable shunt capacitor; wherein the second and fourth filters each include two tunable shunt capacitors; wherein the shunt capacitor is a varactor; wherein parameters of the varactor are controlled by a tuning circuit in response to received complex weights.

16. The system of claim 14 , wherein the first and third filters each include a tunable shunt capacitor; wherein the second and fourth filters each include two tunable shunt capacitors; wherein the shunt capacitor is a digitally tunable capacitor; wherein parameters of the digitally tunable capacitor are controlled by a tuning circuit in response to received complex weights.

17. The system of claim 8 , wherein outer edges of passbands of the first, second, third, and fourth filters are at same frequencies.

18. The system of claim 8 , wherein the first scaler compensates for magnitude changes to the first signal path due to filtering by the first filter; wherein the second scaler compensates for magnitude changes to the second signal path due to filtering by the second filter; wherein the fourth scaler compensates for magnitude changes to the fourth signal path due to filtering by the third filter; wherein the fifth scaler compensates for magnitude changes to the fifth signal path due to filtering by the fourth filter.

19. The system of claim 1 , wherein the first scaler compensates for magnitude changes to the first signal path due to filtering by the first filter; wherein the second scaler compensates for magnitude changes to the second signal path due to filtering by the second filter.

20. A system for multi-peak filter-based analog self-interference cancellation comprising:

a transmit coupler, communicatively coupled to an analog transmit signal of a communication system, that samples the analog transmit signal to create a sampled analog transmit signal;

an analog self-interference canceller, comprising a first signal divider, first and second filters, first, second, and third scalers, and a first signal combiner, wherein the first signal divider splits the analog transmit signal into first, second, and third signal paths; wherein the first filter filters the first signal path and the first scaler scales the first signal path to create a first analog self-interference signal component; wherein the second filter filters the second signal path and the second scaler scales the second signal path to create a second analog self-interference signal component; wherein the third signal path is unfiltered and the third scaler scales the third signal path to create a third analog self-interference signal component; wherein the first filter has a single peak centered at a first frequency; wherein the second filter has exactly two peaks centered at a second frequency and a third frequency respectively; wherein the first signal combiner combines the first, second, and third analog self-interference signal components to form a first analog self-interference cancellation signal;

a receive coupler, communicatively coupled to an analog receive signal of the communication system, that combines the first analog self-interference cancellation signal with the analog receive signal.

21. The system of claim 20 , wherein the first and second filters are resonant element filters; wherein the second filter comprises two resonant elements in parallel.

22. The system of claim 20 , wherein outer edges of passbands of the first filter and the second filter are at same frequencies.

23. The system of claim 20 , wherein the first signal path, associated with the first filter having a single peak, is configured to have a first delay; wherein the second signal path, associated with the second filter having two peaks, is configured to have a second delay; wherein the third signal path, associated with no filter, is configured to have a third delay; wherein a difference between the first delay and the third delay is equal to a difference between the second delay and the first delay.