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

• US 20060217070A1
• Filed: 03/03/2006
• Published: 09/28/2006
• 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.
• Granted Patent: US 7,796,986 B2
• Time in Patent Office: Days
• US Class Current: 455/63.100
• 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:

generating at a radioterminal a measure of an error of a waveform received at the radioterminal;

processing the measure of the error and a measure of at least one other waveform that contributes a component to the waveform received at the radioterminal to obtain at least one interference compensation value; and

combining the at least one interference compensation value with a waveform prior to transmitting the waveform to the radioterminal.

2. The method of claim 1, wherein the waveform received at the radioterminal and the at least one other waveform that contributes a component to the waveform received at the radioterminal include at least one common frequency.

3. The method of claim 2, wherein the waveform received at the radioterminal includes at least one frequency that is not included in the at least one other waveform that contributes a component to the waveform received at the radioterminal.

4. The method of claim 1, wherein transmitting the waveform to the radioterminal is based on a first air interface and wherein the at least one other waveform that contributes a component to the waveform received at the radioterminal is based on a second air interface, and wherein the first air interface is different or substantially the same compared to the second air interface.

5. The method of claim 4, wherein transmitting the waveform to the radioterminal comprises transmitting using a satellite service link through a satellite.

6. The method of claim 5, wherein the measure of an error of a waveform received at the radioterminal is transmitted to an interference reducer using a frequency of a satellite frequency band.

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

8. The method of claim 5, wherein the interference reducer at least partially resides at a satellite and/or at a satellite gateway.

9. The method of claim 1, wherein generating at a radioterminal a measure of an error of a waveform received at the radioterminal comprises transmitting the measure of the error from the radioterminal to an interference reducer.

10. The method of claim 9, wherein transmitting the measure of the error from the radioterminal to an interference reducer comprises transmitting the measure of the error to a satellite gateway, wherein the satellite gateway comprises the interference reducer.

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

12. The method of claim 1, wherein generating at a radioterminal a measure of an error of a waveform received at the radioterminal comprises:

comparing at least one known value to at least one value received at the radioterminal.

13. The method of claim 1, wherein generating at a radioterminal a measure of an error of a waveform received at the 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 received at the radioterminal.

14. The method of claim 1, wherein the combining comprises linear and/or non-linear combining.

15. The method of claim 1, wherein processing the measure of the error and a measure of at least one other waveform that contributes a component to the waveform received at the radioterminal to obtain at least one interference compensation value comprises:

generating the at least one interference compensation value in response to correlating the measure of the at least one other waveform that contributes a component to the waveform received at the radioterminal with the measure of the error.

16. The method of claim 1, wherein processing the measure of the error and a measure of the at least one other waveform that contributes a component to the waveform received at the radioterminal to obtain at least one interference compensation value 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.

17. The method of claim 16, wherein processing the measure of the error and a measure of the at least one other waveform that contributes a component to the waveform received at the radioterminal to obtain at least one interference compensation value further 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 filter coefficient that is changed in response to a change in the measure of the error.

18. The method of claim 1, wherein processing the measure of the error and a measure of the at least one other waveform that contributes a component to the waveform received at the radioterminal to obtain at least one interference compensation value comprises carrying out at least one time alignment between the measure of the error and the measure of the at least one other waveform.

19. A communications system comprising:

a transmitter; and

an interference reducer configured to process a measure of an error of a waveform received at a radioterminal and a measure of at least one other waveform that contributes a component to the waveform received at the radioterminal 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 radioterminal.

20. The communications system of claim 19, wherein the waveform received at the radioterminal and the at least one other waveform that contributes a component to the waveform received at the radioterminal include at least one common frequency.

21. The communications system of claim 20, wherein the waveform received at the radioterminal includes at least one frequency that is not included in the at least one other waveform that contributes a component to the waveform received at the radioterminal.

22. The communications system of claim 19, wherein the transmitter is configured to transmit the interference compensated waveform to the radioterminal based on a first air interface and wherein the at least one other waveform that contributes a component to the waveform received at the radioterminal is based on a second air interface, and the first air interface is different or substantially the same compared to the second air interface.

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

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

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

26. The communications system of claim 19, wherein the at least one other waveform that contributes a component to the waveform received at the radioterminal is a waveform that is transmitted by a space-based and/or terrestrial component.

27. The communications system of claim 19, wherein the measure of an error of a waveform received at a radioterminal is transmitted by the radioterminal to an interference reducer.

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

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

30. The communications system of claim 19, wherein the radioterminal is configured to generate the measure of an error of a waveform based on a comparison of at least one known value to at least one value received at the radioterminal.

31. The communications system of claim 19, wherein the radioterminal is configured to generate the measure of an error of a waveform based on the radioterminal making at least one decision and comparing at least one value associated with the at least one decision to at least one value received at the radioterminal.

32. The communications system of claim 19, wherein the interference reducer is configured to use linear and/or non-linear combining to combine the at least one interference compensation value with a waveform to generate the interference compensated waveform.

33. The communications system of claim 19, wherein the interference reducer is configured to process the measure of an error of a waveform received at a radioterminal and the measure of at least one other waveform that contributes a component to the waveform received at the radioterminal to obtain at least one interference compensation value by generating the at least one interference compensation value in response to correlating the measure of the at least one other waveform that contributes a component to the waveform received at the radioterminal with the measure of the error.

34. The communications system of claim 19, wherein the interference reducer is configured to process the measure of an error of a waveform received at a radioterminal and the measure of at least one other waveform that contributes a component to the waveform received at the radioterminal to obtain at least one interference compensation value by 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.

35. The communications system of claim 34, wherein the interference reducer is configured to process the measure of an error of a waveform received at a radioterminal and the measure of at least one other waveform that contributes a component to the waveform received at the radioterminal to obtain at least one interference compensation value further by 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 each using at least one filter coefficient that is changed in response to a change in the measure of the error.

36. The communications system of claim 19, wherein the interference reducer is configured to process the measure of an error of a waveform received at a radioterminal and the measure of at least one other waveform that contributes a component to the waveform received at the radioterminal 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.