Advanced Signal Processors for Interference Suppression in Baseband Receivers

• US 20110069796A1
• Filed: 12/01/2010
• Published: 03/24/2011
• Est. Priority Date: 04/07/2005
• Status: Abandoned Application

• Current Assignee: III Holdings 1, LLC
• Original Assignee: Rambus Inc.
• Inventors: Scharf, Louis L., Nagarajan, Vijay
• Application Number:
  US12/958,141
• Publication Number:
  US 20110069796A1
• Time in Patent Office: Days
• US Class Current: 375/348
• CPC Class Codes: H04B 1/1027 assessing signal quality or detecting noise/interference for the received signal
• CPC Class Codes: H04B 1/1081 Reduction of multipath noise by equalising H04B7/005
• CPC Class Codes: H04B 1/126 having multiple inputs, e.g. auxiliary antenna for receiving interfering signal aerials in general H01Q
• CPC Class Codes: H04B 1/7105 Joint detection techniques, e.g. linear detectors
• CPC Class Codes: H04B 1/7107 Subtractive interference cancellation
• CPC Class Codes: H04B 1/7117 Selection, re-selection, allocation or re-allocation of paths to fingers, e.g. timing offset control of allocated fingers
• CPC Class Codes: H04B 1/712 Weighting of fingers for combining, e.g. amplitude control or phase rotation using an inner loop
• CPC Class Codes: H04B 2001/1045 Adjacent-channel interference
• CPC Class Codes: H04B 2201/70719 CDMA2000
• CPC Class Codes: H04B 2201/70979 Fat finger issues in RAKE receivers
• CPC Class Codes: H04B 7/0678 using different spreading codes between antennas code allocation H04J13/16
• CPC Class Codes: H04B 7/0891 Space-time diversity rake receivers H04B1/7115; space-time decoding H04L1/0631
• CPC Class Codes: H04J 13/0022 PN, e.g. Kronecker
• CPC Class Codes: H04J 13/20 having an orthogonal variable spreading factor [OVSF]

Abstract

A multi-mode receiver includes a channel decomposition module (e.g., a Rake receiver) for separating a received signal into multipath components, an interference selector for selecting interfering paths and subchannels, a synthesizer for synthesizing interference signals from selected sub channel symbol estimates, and an interference canceller for cancelling selected interference in the received signal. At least one of the channel decomposition module, the synthesizer, and the interference canceller are configurable for processing multi-mode signals.

Claims

1. A multi-mode receiver, comprising:

a channel decomposition module configured for performing a decomposition of a communication channel into a plurality of subchannels;

a baseband receiver comprising an upstream baseband processor and a downstream baseband processor;

an interference suppressor coupled between the upstream baseband processor and the downstream baseband processor;

wherein at least one of the channel decomposition module, the baseband receiver, and the interference suppressor is configurable for processing multi-mode signals;

an interference selector coupled to the downstream baseband processor and configured for selecting subchannels that are likely to contribute interference to at least one signal of interest, for producing at least one selected interference symbol;

a synthesizer configured to synthesize a synthesized interference signal from the at least one selected interference symbol; and

a channel emulator configured to produce an estimated interference signal from the synthesized interference signal.

2. The receiver recited in claim 1, wherein the synthesizer is configured for producing a linear combination of synthesized interference signals.

3. The receiver recited in claim 1, wherein the interference selector is configured to recursively determine subsets of channels that may be used in subtractions.

4. The receiver recited in claim 1, wherein the interference suppressor comprises a subtractive suppressor.

5. The receiver recited in claim 1, wherein the baseband receiver further comprises a receiver filter matched to a transmit filter.

6. The receiver recited in claim 1, wherein the channel decomposition module includes a physical channel identification module configured to estimate a multipath profile.

7. The receiver recited in claim 1, wherein the multi-mode signals include at least one of a set of signals, including signals corresponding to multiple transmission protocols, signals corresponding to multiple variations of a particular transmission protocol, and signals corresponding to multiple receiver signal-processing techniques.

8. The receiver recited in claim 1, wherein the interference suppressor is configured to process a sequence of estimated symbols.

9. The receiver recited in claim 1, wherein at least one of the synthesizer and the channel emulator is configured to synchronize the estimated interference signal with the signal output from the baseband receiver.

10. The receiver recited in claim 1, wherein the channel decomposition module is configured to track signals that are identified as at least one of strong sources and strong multi path components.

11. The receiver recited in claim 1, wherein the baseband receiver comprises a Rake receiver and an equalizer, the baseband receiver being configured for selecting at least one of the Rake receiver and the equalizer for processing a received baseband signal.

12. The receiver recited in claim 1 configured to operate in at least one of a transmit diversity system and a receive-diversity system.

13. The receiver recited in claim 1, wherein the interference suppressor includes an interference-suppressed signal combiner.

14. The receiver recited in claim 13, wherein the interference-suppressed signal combiner is configured to combine the outputs over a plurality of subchannels and multi paths.

15. The receiver recited in claim 13, wherein the interference-suppressed signal combiner is configured to perform at least one of Maximal Ratio Combining, Equal Gain Combining, Minimum Mean Squared Error Combining, Minimum Variance Unbiased Combining, and Selection Combining

16. The receiver recited in claim 1 configured to operate in at least one of a base station and a handset.

17. The receiver recited in claim 1 integrated in a chipset.

18. The receiver recited in claim 1, wherein at least one of the channel decomposition module, the baseband receiver, and the interference suppressor is configurable for processing a plurality of signal types of a set of signals, the set including GSM signals, CDMA signals, W-CDMA signals, and OFDM signals.

19. The receiver recited in claim 1, wherein at least one of the channel decomposition module, the baseband receiver, and the interference suppressor is configurable for processing a plurality of signal types of a set of signals, the set including CDMA signals, W-CDMA signals, and OFDM signals.

20. An interference suppression system configurable to operate in a multi-mode receiver, comprising:

a means for performing decomposition of a communication channel into a plurality of subchannels;

a means for performing baseband processing, comprising a means for performing upstream baseband processing and a means for performing downstream baseband processing;

a means for suppressing interference;

wherein at least one of the means for performing decomposition, the means for performing baseband processing, and the means for suppressing interference is configurable for processing multi-mode signals;

a means for selecting subchannels that are likely to contribute interference to at least one signal of interest, for producing at least one selected interference symbol;

a means for synthesizing a synthesized interference signal from the at least one selected interference symbol; and

a means for performing channel emulation to produce an estimated interference signal from the synthesized interference signal.

21. The interference suppression system recited in claim 20, wherein the means for synthesizing further comprises at least one means for compensating for multipath delay in a received baseband signal.

22. The interference suppression system recited in claim 20, further comprising a means for producing a linear combination of synthesized interference signals.

23. The interference suppression system recited in claim 20, wherein the means for selecting is configured to recursively determine subsets of channels that may be used in subtractions of increasing dimension.

24. The interference suppression system recited in claim 20, wherein the means for synthesizing further comprises a means for imparting a delay to the at least one estimated interference signal in order to synchronize the at least one synthesized interference signal with a received baseband signal.

25. The interference suppression system recited in claim 20, wherein the means for selecting includes a means for combining outputs from the means for suppressing.

26. The interference suppression system recited in claim 25, wherein the means for combining outputs is configured to combine the outputs over a plurality of subchannels and multi paths.

27. The interference suppression system recited in claim 25, wherein means for combining outputs is configured to perform at least one of Maximal Ratio Combining, Equal Gain Combining, Minimum Mean Squared Error Combining, Minimum Variance Unbiased Combining, and Selection Combining

28. The interference suppression system recited in claim 20, wherein the multi-mode signals include at least one of a set of signals, including signals corresponding to multiple transmission protocols, signals corresponding to multiple variations of a particular transmission protocol, and signals corresponding to multiple receiver signal-processing techniques.

29. The interference suppression system recited in claim 20, wherein the means for suppressing interference is configured to process sequences of estimated symbols.

30. The interference suppression system recited in claim 20 configured to operate in at least one of a transmit-diversity system and a receive-diversity system.

31. The interference suppression system recited in claim 20, wherein the means for performing baseband processing comprises a means for performing Rake reception and a means for equalizing, the means for performing baseband processing being configured for selecting at least one of the means for performing Rake reception and the means for equalizing for processing a received baseband signal.

32. The interference suppression system recited in claim 20, wherein at least one of the means for performing decomposition, the means for performing baseband processing, and the means for suppressing interference is configurable for processing a plurality of signal types of a set of signals, the set including GSM signals, CDMA signals, W-CDMA signals, and OFDM signals.

33. The interference suppression system recited in claim 20, wherein at least one of the means for performing decomposition, the means for performing baseband processing, and the means for suppressing interference is configurable for processing a plurality of signal types of a set of signals, the set including CDMA signals, W-CDMA signals, and OFDM signals.

34. An interference suppression method configurable to operate in a multi-mode receiver, comprising:

decomposing a communication channel into a plurality of subchannels in a receiver;

performing receiver baseband processing on one or more of the subchannels;

performing interference suppression on the one of more of the subchannels;

adapting at least one of decomposing, performing receiver baseband processing, and performing interference suppression to process multi-mode signals;

selecting at least one subchannel that is likely to contribute interference to at least one signal of interest, for producing at least one selected interference symbol;

synthesizing at least one synthesized interference signal from the at least one selected interference symbol; and

subtracting the at least one synthesized interference signal from a received baseband signal.

35. The interference suppression method recited in claim 34, wherein selecting at least one subchannel includes recursively determining subsets of channels that may be used in subtractions of increasing dimension.

36. The interference suppression method recited in claim 34, wherein selecting at least one subchannel includes tracking signals that are identified as at least one of strong sources and strong multi path components.

37. The interference suppression method recited in claim 34, wherein synthesizing further comprises processing the at least one synthesized interference signal to emulate predetermined channel distortions in the received baseband signal.

38. The interference suppression method recited in claim 34, wherein synthesizing includes imparting a delay to the at least one estimated interference signal in order to synchronize the at least one synthesized interference signal with the received baseband signal.

39. The interference suppression method recited in claim 34, wherein synthesizing includes imparting channel distortions onto the at least one synthesized interference signal.

40. The interference suppression method recited in claim 34, further comprising combining a plurality of the at least one synthesized interference signal for producing a linear combination of synthesized interference signals.

41. The interference suppression method recited in claim 34, wherein decomposing includes estimating a multi path profile.

42. The interference suppression method recited in claim 34, wherein the multi-mode signals include at least one of a set of signals, including signals corresponding to multiple transmission protocols, signals corresponding to multiple variations of a particular transmission protocol, and signals corresponding to multiple receiver signal-processing techniques.

43. The interference suppression method recited in claim 34 configured to operate in at least one of a transmit-diversity system and a receive-diversity system.

44. The interference suppression method recited in claim 34, wherein suppressing interference includes performing subtractive suppression.

45. The interference suppression method recited in claim 34, wherein suppressing interference includes processing sequences of estimated symbols.

46. The interference suppression method recited in claim 34, wherein suppressing interference includes combining a plurality of interference-suppressed signals.

47. The interference suppression method recited in claim 46, wherein combining includes combining the plurality of interference-suppressed signals over a plurality of subchannels and multipaths.

48. The interference suppression method recited in claim 46, wherein combining includes at least one of Maximal Ratio Combining, Equal Gain Combining, Minimum Mean Squared Error Combining, Minimum Variance Unbiased Combining, and Selection Combining

49. A digital computer system programmed to perform the method recited in claim 34.

50. A computer-readable medium storing a computer program implementing the method of claim 34.

51. A base station configured to perform the method of claim 34.

52. A handset configured to perform the method of claim 34.

53. A chipset configured to perform the method of claim 34.

54. The interference suppression method recited in claim 34, wherein at least one of decomposing, performing receiver baseband processing, and performing interference suppression is configurable for processing a plurality of signal types of a set of signals, the set including GSM signals, CDMA signals, W-CDMA signals, and OFDM signals.

55. The interference suppression method recited in claim 34, wherein at least one of decomposing, performing receiver baseband processing, and performing interference suppression is configurable for processing a plurality of signal types of a set of signals, the set including CDMA signals, W-CDMA signals, and OFDM signals.