Method and system for providing two-way communication using an overlay of signals over a non-linear communications channel

• US 20030224723A1
• Filed: 05/30/2002
• Published: 12/04/2003
• Est. Priority Date: 05/30/2002
• Status: Abandoned Application

• Current Assignee: Hughes Network Systems LLC (Echostar Corporation)
• Original Assignee: Hughes Network Systems LLC (Echostar Corporation)
• Inventors: Sun, Feng-Wen, Lee, Lin-Nan, Becker, Neal, Karimullah, Khalid
• Application Number:
  US10/158,278
• Publication Number:
  US 20030224723A1
• Time in Patent Office: Days
• US Class Current: 455/12.1
• CPC Class Codes: H04B 7/18528 Satellite systems for providing two-way communications service to a network of fixed stations, i.e. fixed satellite service or very small aperture terminal [VSAT] system

Abstract

An approach is provided for communicating in a radio communication system, such as a satellite network, wherein a terminal and a hub station communicates bi-directionally using a composite signal that is transmitted from a relay station and includes an inbound signal overlaid with an outbound signal. The hub station extracts the inbound signal from the composite signal by compensating for a non-linear effect (an optionally filter delay) associated with the composite signal.

Claims

1. A method for communicating in a radio communication system, the method comprising:

receiving a composite signal including an inbound signal and an outbound signal; and

extracting the inbound signal from the composite signal by compensating for a non-linear effect associated with the composite signal.

2. A method according to claim 1, further comprising:

determining the non-linear effect based on at least one of a pre-measurement of the non-linear effect and the received composite signal.

3. A method according to claim 2, further comprising:

adaptively learning the non-linear effect based on the received composite signal.

4. A method according to claim 3, wherein the learning step is performed according to at least one of curve fitting estimation and minimum mean squared estimation.

5. A method according to claim 2, further comprising:

generating a reference signal representing the outbound signal.

6. A method according to claim 5, further comprising:

buffering the outbound signal, wherein the outbound signal is used as the reference signal.

7. A method according to claim 5, further comprising:

modifying the reference signal based on the determined non-linear effect;

selectively further modifying the reference signal for filter delay of the composite signal; and

canceling the modified reference signal from the composite signal.

8. A method according to claim 2, further comprising:

matching a plurality of parameters associated with the reference signal to that of the composite signal, wherein the plurality of parameters include at least one of gain, timing, phase, and frequency.

9. A method according to claim 2, further comprising:

selectively modifying the reference signal for filter delay of the composite signal; and

modifying the composite signal based on the determined non-linear effect; and

canceling the modified reference signal from the modified composite signal.

10. A method according to claim 1, wherein the radio communication system includes a terminal in communication with a hub station over a satellite.

11. A method according to claim 1, wherein the composite signal is received according to a polarization frequency reuse scheme, and the composite signal occupies one of a plurality of polarization components, the method further comprising:

correlating the one polarization component with another one of the plurality of polarization components; and

canceling the other polarization component.

12. A system for communicating in a radio communication system, the system comprising:

a receiver circuit configured to receive a composite signal including an inbound signal and an outbound signal; and

a cancellation module configured to extract the inbound signal from the composite signal by compensating for a non-linear effect associated with the composite signal.

13. A system according to claim 12, further comprising:

a non-linearity compensation module configured to determine the non-linear effect based on at least one of a pre-measurement of the non-linear effect and the received composite signal.

14. A system according to claim 13, wherein the non-linearity compensation module determines the non-linear effect by adaptively learning the non-linear effect based on the received composite signal.

15. A system according to claim 14, wherein the non-linearity compensation module adaptively learns according to at least one of curve fitting estimation and minimum mean squared estimation.

16. A system according to claim 13, further comprising:

a signal reconstruction module configured to generate a reference signal representing the outbound signal.

17. A system according to claim 16, further comprising:

memory configured to store the outbound signal, wherein the outbound signal is used as the reference signal.

18. A system according to claim 16, further comprising:

a non-linearity compensation module configured to modify the reference signal based on the determined non-linear effect.

19. A system according to claim 18, further comprising:

a group delay compensation module configured to modify the reference signal for filter delay of the composite signal.

20. A system according to claim 13, wherein the non-linearity compensation module is further configured to match a plurality of parameters associated with the reference signal to that of the composite signal, wherein the plurality of parameters include at least one of gain, timing, phase, and frequency.

21. A system according to claim 13, further comprising:

a non-linearity compensation module configured to modify the composite signal based on the determined non-linear effect.

22. A system according to claim 21, further comprising:

a group delay compensation module configured to modify the reference signal for filter delay of the composite signal.

23. A system according to claim 12, wherein the radio communication system includes a terminal in communication with a hub station over a satellite.

24. A system according to claim 12, wherein the composite signal is received according to a polarization frequency reuse scheme, and the composite signal occupies one of a plurality of polarization components, the system further comprising:

a correlation module configured to correlate the one polarization component with another one of the plurality of polarization components; and

a polarization cancellation module configured to cancel the other polarization component.

25. A device for communicating in a radio communication system, the device comprising:

means for receiving a composite signal including an inbound signal and an outbound signal; and

means for extracting the inbound signal from the composite signal by compensating for a non-linear effect associated with the composite signal.

26. A device according to claim 25, further comprising:

means for determining the non-linear effect based on at least one of a pre-measurement of the non-linear effect and the received composite signal.

27. A device according to claim 26, wherein the determining means determines the non-linear effect by adaptively learning the non-linear effect based on the received composite signal.

28. A device according to claim 27, wherein the determining means adaptively learns according to at least one of curve fitting estimation and minimum mean squared estimation.

29. A device according to claim 26, further comprising:

means for generating a reference signal representing the outbound signal.

30. A device according to claim 29, further comprising:

means for buffering the outbound signal, wherein the outbound signal is used as the reference signal.

31. A device according to claim 29, further comprising:

means for modifying the reference signal based on the determined non-linear effect.

32. A device according to claim 31, further comprising:

means for modifying the reference signal for filter delay of the composite signal; and

means for canceling the modified reference signal from the composite signal.

33. A device according to claim 26, further comprising:

means for matching a plurality of parameters associated with the reference signal to that of the composite signal, wherein the plurality of parameters include at least one of gain, timing, phase, and frequency.

34. A device according to claim 26, further comprising:

means for modifying the composite signal based on the determined non-linear effect.

35. A device according to claim 34, further comprising:

means for modifying the reference signal for filter delay of the composite signal; and

means for canceling the modified reference signal from the modified composite signal.

36. A device according to claim 25, wherein the radio communication system includes a terminal in communication with a hub station over a satellite.

37. A device according to claim 25, wherein the composite signal is received according to a polarization frequency reuse scheme, and the composite signal occupies one of a plurality of polarization components, the device further comprising:

means for correlating the one polarization component with another one of the plurality of polarization components; and

means for canceling the other polarization component.

38. A computer-readable medium carrying one or more sequences of one or more instructions for communicating in a radio communication system, when executed by one or more processors, cause the one or more processors to perform the steps of:

receiving a composite signal including an inbound signal and an outbound signal; and

extracting the inbound signal from the composite signal by compensating for a non-linear effect associated with the composite signal.

39. A computer-readable medium according to claim 38, wherein the one or more processors further perform the step of:

determining the non-linear effect based on at least one of a pre-measurement of the non-linear effect and the received composite signal.

40. A computer-readable medium according to claim 39, wherein the one or more processors further perform the step of:

adaptively learning the non-linear effect based on the received composite signal.

41. A computer-readable medium according to claim 40, wherein the learning step is performed according to at least one of curve fitting estimation and minimum mean squared estimation.

42. A computer-readable medium according to claim 39, wherein the one or more processors further perform the step of:

generating a reference signal representing the outbound signal.

43. A computer-readable medium according to claim 42, wherein the one or more processors further perform the step of:

buffering the outbound signal, wherein the outbound signal is used as the reference signal.

44. A computer-readable medium according to claim 42, wherein the one or more processors further perform the steps of:

modifying the reference signal based on the determined non-linear effect;

selectively further modifying the reference signal for filter delay of the composite signal; and

canceling the modified reference signal from the composite signal.

45. A computer-readable medium according to claim 39, wherein the one or more processors further perform the step of:

matching a plurality of parameters associated with the reference signal to that of the composite signal, wherein the plurality of parameters include at least one of gain, timing, phase, and frequency.

46. A computer-readable medium according to claim 39, wherein the one or more processors further perform the steps of:

selectively modifying the reference signal for filter delay of the composite signal; and

modifying the composite signal based on the determined non-linear effect; and

canceling the modified reference signal from the modified composite signal.

47. A computer-readable medium according to claim 38, wherein the radio communication system includes a terminal in communication with a hub station over a satellite.

48. A computer-readable medium according to claim 38, wherein the composite signal is received according to a polarization frequency reuse scheme, and the composite signal occupies one of a plurality of polarization components, the one or more processors further performing the steps of:

correlating the one polarization component with another one of the plurality of polarization components; and

canceling the other polarization component.

49. A method for communicating in a radio communication system including a terminal and a hub station, the method comprising:

receiving an inbound signal from the terminal and an outbound signal from the hub station; and

transmitting a composite signal including the inbound signal and the outbound signal to the hub station, wherein the station extracts the inbound signal from the composite signal by compensating for a non-linear effect associated with the composite signal.

50. A method according to claim 49, wherein the hub station is configured to perform the step of:

determining the non-linear effect based on at least one of a pre-measurement of the non-linear effect and the received composite signal.

51. A method according to claim 50, wherein the hub station is configured to further perform the step of:

adaptively learning the non-linear effect based on the received composite signal.

52. A method according to claim 51, wherein the learning step is performed according to at least one of curve fitting estimation and minimum mean squared estimation.

53. A method according to claim 50, wherein the hub station is configured to perform the step of:

generating a reference signal representing the outbound signal.

54. A method according to claim 53, wherein the hub station is configured to perform the step of:

buffering the outbound signal, wherein the outbound signal is used as the reference signal.

55. A method according to claim 53, wherein the hub station is configured to perform the steps of:

modifying the reference signal based on the determined non-linear effect;

selectively further modifying the reference signal for filter delay of the composite signal; and

canceling the modified reference signal from the composite signal.

56. A method according to claim 50, wherein the hub station is configured to perform the step of:

matching a plurality of parameters associated with the reference signal to that of the composite signal, wherein the plurality of parameters include at least one of gain, timing, phase, and frequency.

57. A method according to claim 50, wherein the hub station is configured to perform the steps of:

selectively modifying the reference signal for filter delay of the composite signal; and

modifying the composite signal based on the determined non-linear effect; and

canceling the modified reference signal from the modified composite signal.

58. A method according to claim 49, wherein the composite signal is transmitted according to a polarization frequency reuse scheme, and the composite signal occupies one of a plurality of polarization components, the hub station being configured to perform the steps of:

correlating the one polarization component with another one of the plurality of polarization components; and

canceling the other polarization component.