Reducing interference in a wireless communications signal in the frequency domain

• US 7,587,171 B2
• Filed: 03/03/2006
• Issued: 09/08/2009
• Est. Priority Date: 03/09/2005
• Status: Expired due to Fees

• Current Assignee: Mobile Satellite Venture LP
• Original Assignee: ATC Technology Corporation (FedEx Corporation)
• Inventors: Evans, Richard O., Karabinis, Peter D.
• Primary Examiner(s): Kincaid; Lester
• Assistant Examiner(s): CAI, WAYNE HUU
• Application Number:
  US11/367,955
• Publication Number:
  US 20060205346A1
• Time in Patent Office: 1,285 Days
• Field of Search: 455/427, 455/114.2, 455/278.1, 455/296, 455/63.1
• US Class Current: 455/63.1
• CPC Class Codes: H04B 1/1036 with automatic suppression of narrow band noise or interference, e.g. by using tuneable notch filters H04B1/123 takes precedence; filter circuits H03H
• CPC Class Codes: H04B 7/18513 Transmission in a satellite or space-based system

Abstract

Methods of reducing interference in wireless communications in a communications system are provided. A wireless communications signal is received within a frequency band. The wireless communications signal includes a desired component and an undesired interference component. The interference component may be caused by, for example, communications by another component of the communications system using frequencies in the frequency band. The received communications signal is converted to a frequency domain representation. Frequencies of the interference component of the frequency domain signal are identified. At least some of the identified frequencies of the interference component of the frequency domain signal are attenuated to generate an interference attenuated frequency domain signal. The interference attenuated frequency domain signal is converted to an interference attenuated time domain signal.

Claims

1. A method of reducing interference in wireless communications, the method comprising:

receiving a signal comprising a desired component and an interference component, the desired component and the interference component of the signal having at least one common frequency therebetween;

converting the signal from a time-domain representation to a frequency-domain representation;

identifying the at least one common frequency in the frequency-domain representation;

attenuating the at least one common frequency of the desired component and the interference component of the signal in the frequency-domain representation to generate an interference reduced frequency-domain signal; and

converting the interference reduced frequency-domain signal to a time domain representation so as to generate an interference reduced time-domain signal,

wherein attenuating the at least one common frequency of the desired component and the interference component of the signal in the frequency-domain representation to generate an interference reduced frequency-domain signal comprises attenuating the at least one common frequency of the desired component and the interference component so that both the desired component and the interference component are attenuated at the at least one common frequency thereof.

2. The method of claim 1, wherein:

converting the signal from a time-domain representation to a frequency-domain representation comprises performing a Fourier transform on the signal comprising a desired component and an interference component to obtain the frequency domain representation, and

identifying the at least one common frequency in the frequency-domain representation comprises comparing at least one element of the frequency domain representation to a threshold.

3. The method of claim 2, wherein comparing the at least one element of the frequency domain representation to a threshold comprises:

identifying at least one frequency at which an amplitude of the frequency domain representation exceeds the threshold.

4. The method of claim 2. wherein the Fourier transfrom comprises a discrete-time Fourier transform.

5. The method of claim 4, wherein the discrete-time Fourier transform comprises a Fast Fourier Transform (FFT) and/or a Discrete Fourier Transform (DFT).

6. The method of claim 1, wherein the time-domain representation comprises a discrete time-domain representation.

7. The method of claim 1, wherein receiving comprises receiving the signal via a plurality of different polarizations and/or antenna elements.

8. The method of claim 7 wherein receiving comprises receiving the signal at a space-based component.

9. The method of claim 7, wherein receiving comprises receiving the signal at a terrestrial component.

10. The method of claim 7, wherein receiving comprises receiving the signal at a radioterminal.

11. The method of claim 1, wherein attenuating the at least one common frequency of the signal comprises reducing an amplitude of the at least one common frequency of the signal to zero.

12. The method of claim 1, wherein:

receiving comprises receiving the signal at a satellite gateway; and

the method of identifying and attenuating is carried out at an interference reduction component associated at least partially with the satellite gateway.

13. The method of claim 1, wherein:

receiving comprises receiving the signal at a radioterminal; and

the method of identifying and attenuating is carried out at least partially at the radioterminal.

14. The method of claim 1, wherein:

receiving comprises receiving the signal at a space-based component; and

the method of identifying and attenuating is carried out at least partially at the space-based component.

15. The method of claim 1, wherein:

receiving comprises receiving the signal at a radioterminal from an ancillary terrestrial component that is using frequencies of a satellite frequency band; and

the method of identifying and attenuating is carried out at least partially at the radioterminal.

16. The method of claim 1, wherein:

receiving comprises receiving the signal at an ancillary terrestrial component from a radioterminal that is using frequencies of a satellite frequency band; and

the method of identifying and attenuating is carried out at least partially at an interference reduction component that is associated at least partially with the ancillary terrestrial component.

17. A wireless communications system comprising:

a receiver configured to receive a signal comprising a desired component and an interference component, the desired component and the interference component of the signal having at least one common frequency therebetween; and

an interference reduction component configured to convert the signal comprising a desired component and an interference component from a time domain representation to a frequency domain representation, to identify the at least one common frequency in the frequency domain representation, to attenuate the at least one common frequency of the desired component and the interference component of the signal in the frequency domain representation to generate an interference reduced frequency domain signal and to convert the interference reduced frequency domain signal to a time domain representation so as to generate an interference reduced time-domain signal, wherein the interference reduction component attenuates the at least one common frequency of the desired component and the interference component of the signal in the frequency-domain representation to generate the interference reduced frequency-domain signal by attenuating both the desired component and the interference component at the at least one common frequency thereof.

18. The communications system of claim 17, wherein the interference reduction component is further configured to convert the signal comprising a desired component and an interference component to the frequency domain representation by performing a Fourier transform on the signal comprising a desired component and an interference component, and to compare at least one element of the frequency domain representation to a threshold.

19. The communications system of claim 18, wherein the interference reduction component is further configured to identify at least one frequency at which an amplitude of the frequency domain representation exceeds the threshold.

20. The communications system of claim 18, wherein the Fourier transform comprises a discrete-time Fourier transform.

21. The communications system of claim 20, wherein the discrete-time Fourier transform comprises a Fast Fourier Transform (FFT) and/or a Discrete Fourier Transform (DFT).

22. The communications system of claim 17, wherein the time domain representation comprises a discrete time domain representation.

23. The communications system of claim 17, wherein the receiver is further configured to receive the signal comprising a desired component and an interference component via a plurality of different polarizations and/or antenna elements.

24. The communications system of claim 23, wherein the receiver is a part of a space-based component.

25. The communications system of claim 23, wherein the receiver is at a terrestrial component.

26. The communications system of claim 23, wherein the receiver is part of a radioterminal.

27. The communications system of claim 17, wherein the interference reduction component is further configured to reduce an amplitude of the at least one common frequency of the signal to zero.

28. The communications system of claim 17, wherein the interference reduction component is at least partially a part of a satellite gateway.

29. The communications system of claim 17, wherein the interference reduction component is at least partially a part of a radioterminal.

30. The communications system of claim 17, wherein the interference reduction component is at least partially a part of a space-based component.

31. The communications system of claim 17, further comprising:

a radioterminal configured to receive the signal comprising a desired component and an interference component from an ancillary terrestrial component that is using frequencies of a satellite frequency band, wherein the radioterminal comprises at least partially the interference reduction component.

32. The communications system of claim 17, further comprising:

an ancillary terrestrial component configured to receive the signal comprising a desired component and an interference component from a radioterminal that is using frequencies of a satellite frequency band, wherein the ancillary terrestrial component comprises at least partially the interference reduction component.

33. A wireless communications system comprising:

a receiver configured to receive a signal using a plurality of different polarizations and/or a plurality of antenna elements, the signal comprising a desired component and an interference component wherein the desired component and the interference component of the signal include at least one common frequency therebetween; and

an interference reduction component configured to convert the signal comprising a desired component and an interference component from a time domain representation to a frequency domain representation, to identify the at least one common frequency in the frequency domain representation, to attenuate the at least one common frequency of the desired component and the interference component of the signal in the frequency domain representation to generate an interference reduced frequency domain signal and to convert the interference reduced frequency domain signal to a time domain representation so as to generate an interference reduced time-domain signal, wherein the interference reduction component attenuates the at least one common frequency of the desired component and the interference component of the signal in the frequency-domain representation to generate the interference reduced frequency-domain signal by attenuating both the desired component and the interference component at the at least one common frequency thereof.

34. A wireless communications method comprising:

receiving a signal using a plurality of different polarizations and/or a plurality of antenna elements, the signal comprising a desired component and an interference component wherein the desired component and the interference component of the signal include at least one common frequency therebetween; and

reducing interference by converting the signal comprising a desired component and an interference component from a time domain representation to a frequency domain representation, identifying the at least one common frequency in the frequency domain representation, attenuating the at least one common frequency of the desired component and the interference component of the signal in the frequency domain representation to generate an interference reduced frequency domain signal and converting the interference reduced frequency domain signal to a time domain representation so as to generate an interference reduced time-domain signal,

wherein attenuating the at least one common frequency of the desired component and the interference component of the signal in the frequency domain representation to generate an interference reduced frequency domain signal comprises attenuating the at least one common frequency of the desired component and the interference component so that both the desired component and the interference component are attenuated at the at least one common frequency thereof.