Modification of transmission values to compensate for interference in a satellite down-link communications

• US 7,796,986 B2
• Filed: 03/03/2006
• Issued: 09/14/2010
• Est. Priority Date: 03/11/2005
• Status: Active Grant

• Current Assignee: ATC Technology Corporation (FedEx Corporation)
• Original Assignee: ATC Technology Corporation (FedEx Corporation)
• Inventors: Karabinis, Peter D.
• Primary Examiner(s): Urban; Edward
• Assistant Examiner(s): Hannon; Christian A
• Application Number:
  US11/367,065
• Publication Number:
  US 20060217070A1
• Time in Patent Office: 1,656 Days
• Field of Search: 455/430, 455/432.2, 455/447, 455/448, 455427-429, 4551142-1143, 455133-136, 455/140, 455230-231, 455/269, 455/272, 455/277.2, 455/278.1, 455/303
• US Class Current: 455/430
• CPC Class Codes: H04B 1/1027 assessing signal quality or detecting noise/interference for the received signal
• CPC Class Codes: H04B 1/123 using adaptive balancing or compensation means adaptive filter circuits and algorithms H03H
• CPC Class Codes: H04B 7/18513 Transmission in a satellite or space-based system

Abstract

Methods of compensating for interference in communications in a satellite communications system are provided. At a first radioterminal, a measure of an error in communications received through a first service down-link from a satellite is generated. A communications waveform is identified which causes interference to communications through the first service down-link to the first radioterminal when it is transmitted to a second radioterminal at a frequency that is substantially the same as a frequency of the first service down-link. The measure of the error and a measure of the interfering communications waveform are processed to obtain at least one interference compensation value. The at least one interference compensation value is combined with a waveform that is to be transmitted to the first radioterminal to obtain an interference compensated waveform. The interference compensated waveform is transmitted to the first radioterminal through the first service down-link.

Claims

1. A method of reducing interference, the method comprising:

receiving at an interference reducer from a first radioterminal a measure of an error of a waveform that is received at the first radioterminal;

receiving at the interference reducer from an electronic component a measure of at least one other waveform that has been transmitted to at least one second radioterminal and contributes an interference component to the waveform that is received at the first radioterminal, wherein the electronic component is separate from the first radioterminal and is also separate from the at least one second radioterminal;

operating the interference reducer to process the measure of an error and the measure of at least one other waveform to generate at least one interference compensation value; and

operating the interference reducer to combine the at least one interference compensation value with a waveform to generate an interference compensated waveform prior to transmission of the interference compensated waveform to the first radioterminal.

2. The method of claim 1, wherein the waveform that is received at the first radioterminal and the at least one other waveform that has been transmitted to the at least one second radioterminal and contributes an interference component to the waveform that is received at the first radioterminal include at least one common frequency.

3. The method of claim 2, wherein the waveform that is received at the first radioterminal includes at least one frequency that is not included in the at least one other waveform that has been transmitted to the at least one second radioterminal and contributes an interference component to the waveform that is received at the first radioterminal.

4. The method of claim 1, wherein the waveform that is received at the first radioterminal is received using a first air interface protocol, and the at least one other waveform that has been transmitted to at least one second radioterminal and contributes an interference component to the waveform that is received at the first radioterminal is transmitted to the at least one second radioterminal using a second air interface protocol that is different than the first air interface protocol.

5. The method of claim 4, wherein the waveform that is received at the first radioterminal is received through a satellite service link.

6. The method of claim 1, further comprising:

communicating the measure of the error of the waveform that is received at the first radioterminal to the interference reducer using a frequency of a satellite frequency band.

7. The method of claim 6, wherein the interference reducer at least partially resides at a satellite or at a satellite gateway.

8. The method of claim 1, wherein the at least one other waveform that contributes an interference component to the waveform that is received at the first radioterminal is a waveform that is transmitted by a space-based or terrestrial component.

9. The method of claim 1, wherein:

receiving at an interference reducer from a first radioterminal a measure of an error of a waveform comprises receiving the measure of the error at a satellite gateway that comprises the interference reducer.

10. The method of claim 9, wherein receiving the measure of the error at a satellite gateway comprises receiving the measure of the error using frequencies authorized for use by a space-based component.

11. The method of claim 1, wherein receiving at an interference reducer from a first radioterminal a measure of an error of a waveform that is received at the first radioterminal comprises:

comparing at least one predetermined value to at least one value of the waveform that is received at the first radioterminal.

12. The method of claim 1, wherein receiving at an interference reducer from a first radioterminal a measure of an error of a waveform that is received at the first radioterminal comprises:

making at least one decision and comparing at least one value associated with the at least one decision to at least one value of the waveform that is received at the first radioterminal.

13. The method of claim 1, wherein the combining comprises linear or non-linear combining.

14. The method of claim 1, wherein operating the interference reducer to combine the at least one interference compensation value with a waveform to generate an interference compensated waveform comprises:

generating the at least one interference compensation value in response to correlating the measure of the at least one other waveform that has been transmitted to the at least one second radioterminal and contributes an interference component to the waveform that is received at the first radioterminal with the measure of the error.

15. The method of claim 1, wherein operating the interference reducer to combine the at least one interference compensation value with a waveform to generate an interference compensated waveform comprises:

passing the measure of the at least one other waveform through at least one filter to generate the at least one interference compensation value, wherein the at least one filter is configured to modify the measure of the at least one other waveform using at least one coefficient that is changed in response to a change in the measure of the error.

16. The method of claim 1, wherein operating the interference reducer to combine the at least one interference compensation value with a waveform to generate an interference compensated waveform comprises:

passing the measure of the at least one other waveform through a plurality of filters configured therebetween in parallel to generate the at least one interference compensation value, wherein the plurality of filters are each configured to modify a measure of the at least one other waveform using at least one coefficient that is changed in response to a change in the measure of the error.

17. The method of claim 1, wherein operating the interference reducer to combine the at least one interference compensation value with a waveform to generate an interference compensated waveform comprises carrying out at least one time alignment between the measure of the error and the measure of the at least one other waveform.

18. A communications system comprising:

an electronic component;

a transmitter; and

an interference reducer that is configured to process a measure of an error of a waveform that is received at a first radioterminal and a measure of at least one other waveform that has been transmitted to at least one second radioterminal and contributes an interference component to the waveform that is received at the first radioterminal;

wherein the interference reducer is configured to process the measure of an error and the measure of at least one other waveform in order to obtain at least one interference compensation value, and to combine the at least one interference compensation value with a waveform to generate an interference compensated waveform prior to the transmitter transmitting the interference compensated waveform to the first radioterminal;

wherein the measure of the error is received at the interference reducer from the first radioterminal; and

wherein the electronic component is separate from the first radioterminal and is separate from the at least one second radioterminal, and the electronic component is configured to generate the measure of the at least one other waveform and to provide the measure of the at least one other waveform to the interference reducer.

19. The communications system of claim 18, wherein the waveform that is received at the first radioterminal and the at least one other waveform that has been transmitted to the at least one second radioterminal and contributes an interference component to the waveform that is received at the first radioterminal include at least one common frequency.

20. The communications system of claim 19, wherein the waveform that is received at the first radioterminal includes at least one frequency that is not included in the at least one other waveform that has been transmitted to the at least one second radioterminal and contributes an interference component to the waveform that is received at the first radioterminal.

21. The communications system of claim 18, wherein the transmitter is configured to transmit the interference compensated waveform to the first radioterminal based on a first air interface protocol, wherein the at least one other waveform that has been transmitted to the at least one second radioterminal and contributes an interference component to the waveform that is received at the first radioterminal is based on a second air interface protocol and wherein the first air interface protocol is different than the second air interface protocol.

22. The communications system of claim 21, wherein the transmitter is configured to transmit the interference compensated waveform to the first radioterminal using a satellite service link.

23. The communications system of claim 22, wherein the measure of an error of a waveform is received at the interference reducer using a frequency of a satellite frequency band.

24. The communications system of claim 23, wherein the interference reducer at least partially resides at a satellite or at a satellite gateway.

25. The communications system of claim 18, wherein the at least one other waveform that contributes an interference component to the waveform that is received at the first radioterminal is a waveform that is transmitted by a space-based or terrestrial component.

26. The communications system of claim 18, wherein the measure of an error of a waveform that is received at a first radioterminal is transmitted by the first radioterminal to the interference reducer.

27. The communications system of claim 26, wherein the first radioterminal is configured to transmit the measure of the error to a satellite gateway, wherein the satellite gateway comprises the interference reducer.

28. The communications system of claim 27, wherein the first radioterminal is configured to transmit the measure of the error to the satellite gateway using frequencies authorized for use by a space-based component.

29. The communications system of claim 18, wherein the first radioterminal is configured to generate the measure of an error of a waveform that is received at the first radioterminal based on a comparison of at least one predetermined value with at least one value of the waveform that is received at the first radioterminal.

30. The communications system of claim 18, wherein the first radioterminal is configured to generate the measure of an error of a waveform that is received at the first radioterminal based on the first radioterminal making at least one decision and comparing at least one value associated with the at least one decision to at least one value of the waveform that is received at the first radioterminal.

31. The communications system of claim 18, wherein the interference reducer is configured to use linear or non-linear combining to combine the at least one interference compensation value with a waveform to generate the interference compensated waveform.

32. The communications system of claim 18, wherein the interference reducer is configured to generate the at least one interference compensation value by correlating the measure of the at least one other waveform that contributes an interference component to the waveform that is received at the first radioterminal with the measure of the error of the waveform that is received at the first radioterminal.

33. The communications system of claim 18, wherein the interference reducer is configured to obtain the at least one interference compensation value by passing the measure of the at least one other waveform through at least one filter, wherein the at least one filter is configured to modify the measure of the at least one other waveform using at least one coefficient that is changed in response to a change in the measure of the error.

34. The communications system of claim 18, wherein the interference reducer is configured to obtain at least one interference compensation value by passing the measure of the at least one other waveform through a plurality of filters configured therebetween in parallel, wherein the plurality of filters are each configured to modify the measure of the at least one other waveform each using at least one coefficient that is changed in response to a change in the measure of the error.

35. The communications system of claim 18, wherein the interference reducer is configured to obtain at least one interference compensation value by carrying out at least one time alignment between the measure of the error and the measure of the at least one other waveform.

36. A method of compensating for interference in communications, the method comprising:

receiving from a first transceiver a measure of error in communications that are received at the first transceiver through a first service link;

determining, at an electronic component that is separate from the first transceiver, a measure of at least one waveform that causes interference to communications through the first service link to the first transceiver when the at least one waveform is transmitted to at least one second transceiver;

processing the measure of the error and the measure of the at least one waveform to obtain an interference compensation value;

combining the interference compensation value with a waveform that is to be transmitted to the first transceiver to obtain an interference compensated waveform; and

transmitting the interference compensated waveform to the first transceiver through the first service link.

37. The method of claim 36, wherein the at least one waveform is transmitted to the at least one second transceiver using at least one frequency that is also used to transmit the interference compensated waveform to the first transceiver.

38. The method of claim 36, wherein combining the interference compensation value with a waveform to be transmitted to the first transceiver to obtain an interference compensated waveform comprises:

modifying the waveform to be transmitted to the first transceiver based on the interference compensation value to compensate for interference during transmission of the interference compensated waveform to the first transceiver through the first service link.

39. The method of claim 36, further comprising communicating the at least one waveform that causes interference through a second service link with a satellite.

40. The method of claim 39, wherein the first and second service links are with respective first and second different satellites.

41. The method of claim 36, wherein determining a measure of at least one waveform comprises:

using a terrestrial link to transport a measure of the at least one waveform to an interference compensator.

42. The method of claim 36, wherein the first transceiver comprises a radioterminal receiver and the at least one second transceiver comprises a radioterminal receiver.

43. A system comprising:

a waveform pre-distorter that is configured to receive a measure of an error of a waveform that is received at a first receiver, to receive a measure of an other waveform that is transmitted to a second receiver and contributes an interference component to the waveform received at the first receiver, to process the measure of the error and the measure of the other waveform to derive an interference compensation value by passing the measure of the other waveform through at least one filter that is configured to modify the measure of the other waveform using at least one coefficient that is changed in response to a change in the measure of the error, and to combine the interference compensation value with a waveform that is to be transmitted to the first receiver.

44. The system of claim 43, wherein the first receiver and the second receiver comprise respective first and second wireless receivers.

45. The system of claim 43, wherein the waveform pre-distorter is configured to combine the interference compensation value with the waveform that is to be transmitted to the first receiver to form a pre-distorted waveform such that during propagation of the pre-distorted waveform over a first link towards the first receiver, a level of interference from at least one other waveform that is propagating over at least one other link towards the second receiver, combines with the pre-distorted waveform to reduce a level of interference of the pre-distorted waveform.

46. The system of claim 45, wherein the first link comprises a wireless link and the at least one other link comprises at least one other wireless link.