Joint linear and non-linear cancellation of transmit self-jamming interference

1. A method, comprising:

generating a signal to be transmitted on a first frequency band;

transmitting the generated signal on the first frequency band;

computing an estimated distorted version of the generated signal by applying an adaptive joint linear and non-linear digital filter to the generated signal at baseband;

receiving a composite signal on at least a second frequency band, the composite signal comprising a desired signal and self-jamming interference, wherein the self-jamming interference is caused by a cascaded effect of at least one of non-linear or linear distortions introduced by at least one of transmit or receive chain non-idealities; and

subtracting the estimated distorted version of the generated signal from the composite signal to remove the self-jamming interference.

2. The method of claim 1 , wherein computing the estimated distorted version of the generated signal comprises:

applying a Volterra based filter to the generated signal at baseband, wherein the Volterra based filter comprises linear operators, non-linear operators, and delay elements.

3. The method of claim 2 , wherein the Volterra based filter estimates second-order inter-modulation (IM2) distortion.

4. The method of claim 2 , wherein the Volterra based filter estimates 3 rd harmonic distortion (H3D).

5. The method of claim 2 , wherein applying the Volterra based filter comprises:

applying polynomial generators to the generated signal at baseband to generate one or more Volterra states;

applying one or more weights to the generated one or more Volterra states; and

generating a sum of the one or more weighted Volterra states.

6. The method of claim 5 , wherein applying the polynomial generators to the generated signal at baseband comprises:

applying delay to the generated signal at baseband or to the Volterra states.

7. The method of claim 5 , wherein applying the polynomial generators to the generated signal at baseband comprises:

applying a generic p-th order polynomial expansion to the generated signal at baseband; and

generating at least one of p-th order inter-modulation (IMp) distortion or p-th order harmonic distortion (HpD).

8. The method of claim 5 , further comprising:

generating the one or more weights by minimizing a cost function.

9. The method of claim 8 , wherein the cost function is minimized by utilizing a least mean square (LMS), a recursive least squares (RLS) algorithm, least squares (LS) or a direct matrix inversion method, or other mean squared error methods.

10. The method of claim 1 , wherein the self-jamming interference is caused by a plurality of transmitter sources that are simultaneously active in an apparatus, and the self-jamming interference comprises a p-order inter-modulation distortion where p>1 and m-order harmonic distortion where m>1.

11. The method of claim 1 , wherein the transmitted and received signals are wireless signals.

12. The method of claim 11 , wherein the transmitted and received signals are from different systems that co-exist in the same apparatus.

13. The method of claim 1 , wherein the transmitted and received signals are wired signals.

14. The method of claim 13 , wherein the transmitted and received signals are from different systems that co-exist in the same apparatus.

15. The method of claim 1 , wherein multiple signals transmitted simultaneously by different co-located transmitters or a multi-carrier transceiver inter-modulate reciprocally due to non-linear radio frequency (RF) effects thus producing cross jamming interference in a given receiver band.

16. The method of claim 15 , wherein the estimated distorted version of the generated signal is computed by applying the adaptive joint linear and non-linear digital filter to the multiple transmitted signals at baseband.

17. The method of claim 15 , wherein an estimated joint multiple receiver distortion is computed by applying the adaptive joint linear and non-linear digital filter to the multiple transmitted signals at baseband.

18. The method of claim 1 , wherein the adaptive digital filter comprises linear coefficients and delay to estimate purely linear distortion.

19. The method of claim 1 , wherein the adaptive digital filter comprises a frequency rotator to compensate frequency offset between the estimated distorted version of the generated signal and the self-jamming interference present in the composite signal.

20. An apparatus, comprising:

means for generating a signal to be transmitted on a first frequency band;

means for transmitting the generated signal on the first frequency band;

means for computing an estimated distorted version of the generated signal by applying an adaptive joint linear and non-linear digital filter to the generated signal at baseband;

means for receiving a composite signal on at least a second frequency band, the composite signal comprising a desired signal and self-jamming interference, wherein the self-jamming interference is caused by a cascaded effect of at least one of non-linear or linear distortions introduced by at least one of transmit or receive chain non-idealities; and

means for subtracting the estimated distorted version of the generated signal from the composite signal to remove the self-jamming interference.

21. The apparatus of claim 20 , wherein the means for computing the estimated distorted version of the generated signal comprises:

means for applying a Volterra based filter to the generated signal at baseband, wherein the Volterra based filter comprises linear operators, non-linear operators, and delay elements.

22. The apparatus of claim 21 , wherein the Volterra based filter estimates second-order inter-modulation (IM2) distortion.

23. The apparatus of claim 21 , wherein the Volterra based filter estimates 3 rd harmonic distortion (H3D).

24. The apparatus of claim 21 , wherein the means for applying the Volterra based filter comprises:

means for applying polynomial generators to the generated signal at baseband to generate one or more Volterra states;

means for applying one or more weights to the generated one or more Volterra states; and

means for generating a sum of the one or more weighted Volterra states.

25. The apparatus of claim 24 , wherein the means for applying the polynomial generators to the generated signal at baseband comprises:

means for applying delay to the generated signal at baseband or to the Volterra states.

26. The apparatus of claim 24 , wherein the means for applying the polynomial generators to the generated signal at baseband comprises:

means for applying a generic p-th order polynomial expansion to the generated signal at baseband; and

means for generating at least one of p-th order inter-modulation (IMp) distortion or p-th order harmonic distortion (HpD).

27. The apparatus of claim 24 , further comprising:

means for generating the one or more weights by minimizing a cost function.

28. The apparatus of claim 27 , wherein the cost function is minimized by utilizing a least mean square (LMS), a recursive least squares (RLS) algorithm, least squares (LS) or a direct matrix inversion method, or other mean squared error methods.

29. The apparatus of claim 20 , wherein the self-jamming interference is caused by a plurality of transmitter sources that are simultaneously active in an apparatus, and the self-jamming interference comprises a p-order inter-modulation distortion where p>1 and m-order harmonic distortion where m>1.

30. The apparatus of claim 20 , wherein the transmitted and received signals are wireless signals.

31. The apparatus of claim 30 , wherein the transmitted and received signals are from different systems that co-exist in the same apparatus.

32. The apparatus of claim 20 , wherein the transmitted and received signals are wired signals.

33. The apparatus of claim 32 , wherein the transmitted and received signals are from different systems that co-exist in the same apparatus.

34. The apparatus of claim 20 , wherein multiple signals transmitted simultaneously by different co-located transmitters or a multi-carrier transceiver inter-modulate reciprocally due to non-linear radio frequency (RF) effects thus producing cross jamming interference in a given receiver band.

35. The apparatus of claim 34 , wherein the estimated distorted version of the generated signal is computed by applying the adaptive joint linear and non-linear digital filter to the multiple transmitted signals at baseband.

36. The apparatus of claim 34 , wherein an estimated joint multiple receiver distortion is computed by applying the adaptive joint linear and non-linear digital filter to the multiple transmitted signals at baseband.

37. The apparatus of claim 20 , wherein the adaptive digital filter comprises linear coefficients and delay to estimate purely linear distortion.

38. The apparatus of claim 20 , wherein the adaptive digital filter comprises a frequency rotator to compensate frequency offset between the estimated distorted version of the generated signal and the self-jamming interference present in the composite signal.

39. A computer-program product, comprising a non-transitory computer readable medium having instructions stored thereon, the instructions being executable by one or more processors and the instructions comprising:

instructions for generating a signal to be transmitted on a first frequency band;

instructions for transmitting the generated signal on the first frequency band;

instructions for computing an estimated distorted version of the generated signal by applying an adaptive joint linear and non-linear digital filter to the generated signal at baseband;

instructions for receiving a composite signal on at least a second frequency band, the composite signal comprising a desired signal and self-jamming interference, wherein the self-jamming interference is caused by a cascaded effect of at least one of non-linear or linear distortions introduced by at least one of transmit or receive chain non-idealities; and

instructions for subtracting the estimated distorted version of the generated signal from the composite signal to remove the self-jamming interference.

40. An apparatus, comprising:

at least one processor configured to:

generate a signal to be transmitted on a first frequency band,

transmit the generated signal on the first frequency band,

compute an estimated distorted version of the generated signal by applying an adaptive joint linear and non-linear digital filter to the generated signal at baseband,

receive a composite signal on at least a second frequency band, the composite signal comprising a desired signal and self-jamming interference, wherein the self-jamming interference is caused by a cascaded effect of at least one of non-linear or linear distortions introduced by at least one of transmit or receive chain non-idealities, and

subtract the estimated distorted version of the generated signal from the composite signal to remove the self-jamming interference; and

a memory coupled to the at least one processor.