Systems and methods for searching interference canceled data

• US 20050169354A1
• Filed: 04/11/2005
• Published: 08/04/2005
• Est. Priority Date: 01/23/2004
• Status: Abandoned Application

• Current Assignee: Rambus Inc.
• Original Assignee: Rambus Inc.
• Inventors: Narayan, Anand P., Olson, Eric S.
• Application Number:
  US11/049,112
• Publication Number:
  US 20050169354A1
• Time in Patent Office: Days
• US Class Current: 375/148
• CPC Class Codes: H04B 1/7103 the interference being multiple access interference
• CPC Class Codes: H04B 1/7107 Subtractive interference cancellation
• CPC Class Codes: H04B 1/7113 Determination of path profile

Abstract

Systems and methods for searching interference-canceled data are presented. A searcher finger is configured for acquiring a signal that is buried beneath the noise and interference floor due to interference from other signals. The searcher finger can either search for a signal within an uncanceled digital signal or within a substantially interference canceled signal. The substantially interference canceled signal has one or more interfering signals substantially canceled from the digital signal. A Coded Signal Processing Engine is configured for a generating the substantially interference canceled signal by performing signal cancellation on an input signal and transferring the resulting signal to the searcher finger. The searcher finger acquires a signal within the substantially interference canceled signal. The signal cancellation of the processing engine may improve the signal to noise ratio of a signal, which may improve acquisition of the signal by the searcher finger.

Claims

1. A system, comprising:

a processor configured for substantially canceling one or more interfering signals from a digital signal to generate a substantially interference-canceled signal; and

a first searcher finger communicatively coupled to the processor and configured for performing acquisition to produce an acquired signal from the substantially interference-canceled signal.

2. The system of claim 1, further comprising a processing finger communicatively coupled to the first searcher finger and configured for processing the acquired signal.

3. The system of claim 2, further comprising a connection element configured for selectively transferring either an uncancelled signal or the substantially interference-canceled signal to the processing finger.

4. The system of claim 1, further comprising a connection element configured for selectively transferring either the digital signal or the substantially interference-canceled signal to the first searcher finger for acquisition of the acquired signal.

5. The system of claim 4, further comprising a buffer configured within the processor and communicatively coupled to the connection element, wherein the buffer is configured for applying a first delay to the digital signal.

6. The system of claim 5, wherein the first delay comprises a duration of time corresponding to a second delay introduced by the processing engine.

7. The system of claim 1, further comprising a second searcher finger configured for receiving a time-delayed said digital signal and for acquiring the acquired signal from the time-delayed said digital signal.

8. The system of claim 7, wherein the second searcher finger is configurable within a processing engine and wherein the processing engine comprises the processor.

9. The system of claim 1, wherein the first searcher finger is configurable within a processing engine and wherein the processing engine comprises the processor.

10. The system of claim 1, wherein the first searcher finger is configurable within a receiver and wherein the receiver comprises a processing finger communicatively coupled to the first searcher finger for processing an acquired said acquired signal.

11. The system of claim 10, wherein the receiver is configurable with a handset.

12. The system of claim 10, wherein the receiver is configurable with a base station.

13. The system of claim 1, further comprising a second searcher finger configurable within a receiver and wherein the receiver comprises a processing finger communicatively coupled for processing an acquired signal from either the first searcher finger or the second searcher finger.

14. The system of claim 1, wherein the processor is configured for generating a cancellation operator, wherein the cancellation operator is adapted to be used to substantially cancel the one or more interfering signals from the digital signal.

15. The system of claim 14, further comprising an applicator configured for applying the cancellation operator to an input signal to substantially cancel the one or more interfering signals from the input signal, wherein the input signal comprises the digital signal or a reference code.

16. The system of claim 1, further comprising a matrix generator configured for generating a cancellation matrix adapted to be used to generate a cancellation operator, wherein the cancellation operator is adapted to be used to substantially cancel the one or more interfering signals from the digital signal.

17. The system of claim 16, wherein the cancellation operator comprises the form:

P_s^⊥

=I−

S(S^TS)<sup>−

1</sup>S^T,

wherein P_s^⊥

is the cancellation operator, I is an identity matrix, S is the cancellation matrix and S^T is a transpose of the cancellation matrix.

18. The system of claim 1, further comprising an interference selector configured for selecting the one or more interfering signals for cancellation from a plurality of interfering signals.

19. The system of claim 1, wherein the acquired signal is one of a group, the group consisting of:

a CDMA signal;

a WCDMA signal;

a UMTS signal; and

a GPS signal.

20. A method, comprising:

providing for generating a cancellation operator;

providing for applying the cancellation operator to a digital signal to substantially cancel an interfering signal from the digital signal and generate a substantially interference canceled signal; and

providing for acquiring, with a first searcher finger, a selected signal from the substantially interference canceled signal.

21. The method of claim 20, further comprising providing for selecting the interfering signal for cancellation.

22. The method of claim 21, further comprising providing for generating a cancellation matrix from the interfering signal in response to selecting.

23. The method of claim 22, wherein providing for generating the cancellation operator comprises providing for generating the cancellation operator from the cancellation matrix according to the form:

P_s^⊥

=I−

S(S^TS)<sup>−

1</sup>S^T,

wherein P_s^⊥

is the cancellation operator, I is an identity matrix, S is the cancellation matrix and S^T is a transpose of the cancellation matrix.

24. The method of claim 20, further comprising providing for selectively transferring either a received signal or the substantially interference canceled signal to a processing finger in response to providing for acquiring.

25. The method of claim 24, further comprising providing for processing the substantially interference canceled signal with the processing finger.

26. The method of claim 24, further comprising providing for processing an acquired said selected signal with the processing finger.

27. The method of claim 20, further comprising selectively transferring either the digital signal or the substantially interference canceled signal to the first searcher finger in response to providing for applying.

28. The method of claim 20, further comprising providing for applying a first delay to the digital signal when providing for generating the cancellation operator to generate a time delayed said digital signal.

29. The method of claim 20, further comprising providing for acquiring, with a second searcher finger, the selected signal from the digital signal.

37. A digital computer system programmed to perform the method of claim 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, or 36.

38. A computer-readable medium storing a computer program implementing the method of claim 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, or 36.

30. A method, comprising:

providing for substantially canceling one or more interfering signals from an input signal by applying a cancellation operator to the input signal to produce an output canceled signal;

providing for acquisition of the output canceled signal to produce an acquired signal in response to providing for substantially canceling the one or more interfering signals from the input signal.

31. The method of claim 30, further comprising providing for detection of a digital signal to produce a detected digital signal while detecting the acquired signal from the output canceled signal.

32. The method of claim 31, further comprising providing for delaying the digital signal to account for a delay introduced by substantially canceling the one or more interfering signals.

33. The method of claim 31, further comprising providing for processing either the detected digital signal or the acquired signal detected from the output canceled signal.

34. The method of claim 33, wherein processing comprises:

providing for tracking the selected signal; and

providing for demodulating the selected signal to extract data from the selected signal.

35. The method of claim 30, further comprising providing for generating the cancellation operator from an interference matrix constructed of the one or more interfering signals.

36. The method of claim 35, wherein providing for generating the cancellation operator comprises providing for generating a projection operator according to the following form:

P_s^⊥

=I−

S(S^TS)<sup>−

1</sup>S^T,

wherein P_s^⊥

is the projection operator, I is an identity matrix, S is the interference matrix and S^T is a transpose of the interference matrix.

39. A system, comprising:

means for generating a cancellation operator;

means for applying the cancellation operator to a digital signal to substantially cancel an interfering signal from the digital signal and generate a substantially interference-canceled signal; and

means for performing acquisition with a first searcher finger to produce an acquired signal from the substantially interference-canceled signal.

40. The system of claim 39, further comprising means for selecting the interfering signal for cancellation.

41. The system of claim 40, further comprising means for generating a cancellation matrix from the interfering signal in response to selecting.

42. The system of claim 41, wherein the means for generating the cancellation operator comprises means for generating the cancellation operator from the cancellation matrix according to the form:

P_sy^⊥

=y−

S(S^TS)<sup>−

1</sup>S^Ty,

wherein P_s^⊥

is the cancellation operator, y is the digital signal, I is an identity matrix, S is the cancellation matrix and S^T is a transpose of the cancellation matrix.

43. The system of claim 39, further comprising means for selectively transferring either a received signal or the substantially interference-canceled signal to a processing finger in response to acquiring.

44. The system of claim 43, further comprising means for processing the substantially interference-canceled signal with the processing finger.

45. The system of claim 43, further comprising means for processing the acquired signal with the processing finger.

46. The system of claim 39, further comprising means for selectively transferring at least one of the digital signal and the substantially interference-canceled signal to the first searcher finger in response to applying.

47. The system of claim 39, further comprising means for applying a first delay to the digital signal when generating the cancellation operator to generate a time delayed said digital signal.

48. The system of claim 39, further comprising means for acquiring, with a second searcher finger, the acquired signal from the digital signal.

49. A system, comprising:

means for substantially canceling one or more interfering signals from an input signal by applying a cancellation operator to the input signal to produce an output canceled signal;

means for performing acquisition to produce an acquired signal from the output canceled signal in response to substantially canceling the one or more interfering signals from the input signal.

50. The system of claim 49, further comprising means for providing for detection to a digital signal to produce a detected digital signal while detecting the acquired signal from the output canceled signal.

51. The system of claim 50, further comprising means for delaying the digital signal to account for a delay introduced by substantially canceling the one or more interfering signals.

52. The system of claim 50, further comprising means for processing either the detected digital signal or the acquired signal detected from the output canceled signal.

53. The system of claim 52, wherein the means for processing comprises:

means for tracking the selected signal; and

means for demodulating the selected signal to extract data from the selected signal.

54. The system of claim 49, further comprising means for generating the cancellation operator from an interference matrix constructed of the one or more interfering signals.

55. The system of claim 54, wherein the means for generating the cancellation operator comprises means for generating a projection operator according to the following form:

P_s^⊥

=I−

S(S^TS)<sup>−

1</sup>S^T,

wherein P_s^⊥

is the projection operator, I is an identity matrix, S is the interference matrix and S^T is a transpose of the interference matrix.

56. A handset, comprising:

a processor configured for substantially canceling one or more interfering signals from a digital signal to generate a substantially interference-canceled signal; and

a first searcher finger communicatively coupled to the processor and configured for performing acquisition to produce an acquired signal from the substantially interference-canceled signal.

57. The handset of claim 56, further comprising a processing finger communicatively coupled to the first searcher finger and configured for processing the acquired signal.

58. The handset of claim 57, further comprising a connection element configured for selectively transferring either an uncancelled signal or the substantially interference-canceled signal to the processing finger.

59. The handset of claim 56, further comprising a connection element configured for selectively transferring either the digital signal or the substantially interference-canceled signal to the first searcher finger for acquisition of the acquired signal.

60. The handset of claim 59, further comprising a buffer configured within the processor and communicatively coupled to the connection element, wherein the buffer is configured for applying a first delay to the digital signal.

61. The handset of claim 60, wherein the first delay comprises a duration of time corresponding to a second delay introduced by the processing engine.

62. The handset of claim 56, further comprising a second searcher finger configured for receiving a time-delayed said digital signal and for acquiring the acquired signal from the time-delayed said digital signal.

63. The handset of claim 62, wherein the second searcher finger is configurable within a processing engine and wherein the processing engine comprises the processor.

64. The handset of claim 56, wherein the first searcher finger is configurable within a processing engine and wherein the processing engine comprises the processor.

65. The handset of claim 56, further comprising a processing finger communicatively coupled to the first searcher finger for processing an acquired said acquired signal.

66. The handset of claim 56, further comprising a second searcher finger configurable within a receiver and wherein the receiver comprises a processing finger communicatively coupled for processing an acquired signal from either the first searcher finger or the second searcher finger.

67. The handset of claim 56, wherein the processor is configured for generating a cancellation operator, wherein the cancellation operator is adapted to be used to substantially cancel the one or more interfering signals from the digital signal.

68. The handset of claim 67, further comprising an applicator configured for applying the cancellation operator to an input signal to substantially cancel the one or more interfering signals from the input signal, wherein the input signal comprises the digital signal or a reference code.

69. The handset of claim 56, further comprising a matrix generator configured for generating a cancellation matrix adapted to be used to generate a cancellation operator, wherein the cancellation operator is adapted to be used to substantially cancel the one or more interfering signals from the digital signal.

70. The handset of claim 69, wherein the cancellation operator comprises the form:

P_s^⊥

=I−

S(S^TS)<sup>−

1</sup>S^T,

wherein P_s^⊥

is the cancellation operator, I is an identity matrix, S is the cancellation matrix and S^T is a transpose of the cancellation matrix.

71. The handset of claim 56, further comprising an interference selector configured for selecting the one or more interfering signals for cancellation from a plurality of interfering signals.

72. The handset of claim 56, wherein the acquired signal is one of a group, the group consisting of:

a CDMA signal;

a WCDMA signal;

a UMTS signal; and

a GPS signal.