REDUCED COMPLEXITY INTERFERENCE SUPPRESSION FOR WIRELESS COMMUNICATIONS

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 diagrammatically illustrates an example of a wireless communication system in which principles according to the present invention can be implemented.

FIGS. 2 and 2A diagrammatically illustrate a conventional example of the base station receiver of FIG. 1.

FIG. 3 diagrammatically illustrates a wireless communication receiver apparatus that uses a shared inverse correlation matrix according to exemplary embodiments of the invention.

FIG. 4 diagrammatically illustrates a weight computer of FIG. 3 according to exemplary embodiments of the invention.

FIG. 4A illustrates examples of zero-padded vectors that can be used in the weight computer of FIG. 4.

FIG. 5 diagrammatically illustrates a weight computer of FIG. 3 according to further exemplary embodiments of the invention

FIG. 6 diagrammatically illustrates a wireless communication receiver apparatus that uses a shared correlation matrix according to exemplary embodiments of the invention.

FIG. 7 diagrammatically illustrates a weight computer of FIG. 6 according to exemplary embodiments of the invention.

FIG. 8 diagrammatically illustrates a weight computer of FIG. 6 according to further exemplary embodiments of the invention.

FIG. 9 diagrammatically illustrates a wireless communication receiver apparatus that uses a shared parameter estimate according to exemplary embodiments of the invention.

FIG. 10 graphically illustrates examples of users' rake finger delays.

FIG. 11 diagrammatically illustrates a wireless communication receiver apparatus that uses a shared correlation values according to exemplary embodiments of the invention.

FIGS. 12-14 graphically illustrate exemplary relationships between users' rake finger delays, and delays used to produce impairment correlation values according to exemplary embodiments of the invention.

FIG. 15 is generally similar to FIGS. 3, 6, 9 and 11, but diagrammatically illustrates a wireless communication receiver apparatus that implements chip equalization according to exemplary embodiments of the invention.

Claims

1. A CDMA wireless communication receiver apparatus, comprising: an input for providing a communication signal which has been transmitted over a wireless communication link and which includes interference and a plurality of communication signal components;an interference statistic unit coupled to said input for producing in response to said communication signal a set of data indicative of a statistical characteristic of said interference; anda plurality of signal processing paths that correspond respectively to said plurality of communication signal components, each of said signal processing paths coupled to said interference statistic unit, each of said signal processing paths receiving said set of data for sharing among each of said signal processing paths in common, and each of said signal processing paths applying to said shared set of data a signal processing operation associated with the corresponding communication signal component.
2. The apparatus of claim 1, wherein said set of data indicates a second order statistical property of said interference.
3. The apparatus of claim 1, wherein said set of data is an inverse correlation matrix associated with said interference.
4. The apparatus of claim 3, including a plurality of channel estimators respectively associated with the communication signal components and coupled to said input for providing respective channel estimate vectors that are respectively associated with the communication signal components, and a plurality of vector adjusters respectively associated with the communication signal components, each said vector adjuster coupled between the associated channel estimator and the associated signal processing path, said vector adjusters applying respective adjustments to the associated channel estimate vectors to produce respectively corresponding adjusted vectors, and each said signal processing path combining the associated adjusted vector with said inverse correlation matrix to produce a weight vector for use in combining signals that have been despread for the associated communication signal component.
5. The apparatus of claim 4, wherein each of said adjustments includes zero-padding the associated channel estimate vector to compensate for a difference between rake finger delays employed for the associated communication signal component and delays used by said interference statistic unit to produce said data.
6. The apparatus of claim 3, wherein said signal processing paths include respective matrix adjusters that apply respective adjustments to said inverse correlation matrix to produce respectively corresponding adjusted matrices, each said signal processing path receiving a channel estimation vector that corresponds to the associated communication signal component, and each said signal processing path combining the associated channel estimation vector with the associated adjusted matrix to produce a weight vector for use in combining signals that have been despread for the associated communication signal component.
7. The apparatus of claim 6, wherein each of said adjustments includes removing a portion of said inverse correlation matrix to compensate for a difference between rake finger delays employed for the associated communication signal component and delays used by said interference statistic unit to produce said data.
8. The apparatus of claim 1, wherein said set of data is a correlation matrix associated with said interference.
9. The apparatus of claim 8, wherein said signal processing paths include respective interpolation units for performing respective interpolation operations with respect to correlation values in said correlation matrix, each of said interpolation operations compensating for a difference between rake finger delays employed for the associated communication signal component and delays used by said interference statistic unit to produce said data.
10. The apparatus of claim 9, wherein each of said interpolation operations produces an interpolated matrix, said signal processing paths including respective matrix inverters, each said matrix inverter coupled to the associated interpolation unit for inverting the associated interpolated matrix to produce an inverted matrix, each said signal processing path receiving a channel estimation vector that corresponds to the associated communication signal component, and each said signal processing path combining the associated channel estimation vector with the associated inverted matrix to produce a weight vector for use in combining signals that have been despread for the associated communication signal component.
11. The apparatus of claim 9, wherein each of said interpolation operations produces an interpolated matrix, each said signal processing path receiving a channel estimation vector that corresponds to the associated communication signal component, and each said signal processing path using the associated channel estimation vector and the associated interpolated matrix to produce a weight vector for use in combining signals that have been despread for the associated communication signal component.
12. The apparatus of claim 11, wherein each said signal processing path applies a Gauss-Seidel operation with respect to the associated channel estimation vector and the associated interpolated matrix to produce the associated weight vector.
13. The apparatus of claim 1, wherein said interference statistic unit produces said set of data based on a set of delays.
14. The apparatus of claim 13, wherein said interference statistic unit determines said delays based on information indicative of demodulation delays employed for said communication signal components.
15. The apparatus of claim 14, wherein, for each of said communication signal components, said demodulation delays employed for said communication signal components define a subset of said set of delays.
16. The apparatus of claim 15, wherein said set of delays is a union of said demodulation delays employed for said communication signal components.
17. The apparatus of claim 13, wherein, said set of delays is an equally spaced grid of delays, and some of said demodulation delays employed for said communication signal components are not synchronized with any of said delays.
18. The apparatus of claim 1, wherein said set of data includes a set of correlation values associated with said interference, said signal processing paths including respective matrix construction units, each said matrix construction unit using correlation values from said set to produce for the associated communication signal component a corresponding correlation matrix associated with said interference.
19. The apparatus of claim 18, wherein said matrix construction units interpolate correlation values of said set.
20. The apparatus of claim 18, wherein said interference statistic unit produces said correlation values by averaging correlation values that correspond to different chip sample phases.
21. The apparatus of claim 18, wherein all of said correlation values of said set correspond to the same chip sample phase.
22. A method for use in a CDMA communication receiver, comprising: providing a communication signal which has been transmitted over a wireless communication link and which includes interference and a plurality of communication signal components;producing in response to said communication signal a set of data indicative of a statistical characteristic of said interference;making said set of data available to be shared in support of each of said communication signal components in common; andfor each of said communication signal components, applying to said shared set of data a signal processing operation associated with said communication signal component.
23. The method of claim 22, wherein said set of data is an inverse correlation matrix associated with said interference, and including, for each of said communication signal components, applying an adjustment to a channel estimate vector associated with the communication signal component to produce a corresponding adjusted vector, andcombining the adjusted vector with said inverse correlation matrix to produce a weight vector for use in combining signals that have been despread for the communication signal component.
24. The method of claim 23, wherein each of said adjustments includes zero-padding the associated channel estimate vector to compensate for a difference between rake finger delays employed for the associated communication signal component and delays used in said producing step.
25. The method of claim 22, wherein said set of data is an inverse correlation matrix associated with said interference, and including, for each of said communication signal components, applying an adjustment to said inverse correlation matrix to produce a corresponding adjusted matrix, andcombining the adjusted matrix with a channel estimation vector associated with the communication signal component to produce a weight vector for use in combining signals that have been despread for the communication signal component.
26. The method of claim 25, wherein each of said adjustments includes removing a portion of said inverse correlation matrix to compensate for a difference between rake finger delays employed for the associated communication signal component and delays used in said producing step.
27. The method of claim 22, wherein said set of data is a correlation matrix associated with said interference, and including, for each of said communication signal components, performing an interpolation operation with respect to correlation values in said correlation matrix to compensate for a difference between rake finger delays employed for the communication signal component and delays used in said producing step.
28. The method of claim 27, wherein each of said interpolation operations produces an interpolated matrix, and including, for each of said communication signal components, inverting the associated interpolated matrix to produce an inverted matrix, andcombining the inverted matrix with a channel estimation vector associated with the communication signal component to produce a weight vector for use in combining signals that have been despread for the communication signal component.
29. The method of claim 27, wherein each of said interpolation operations produces an interpolated matrix, and including, for each of said communication signal components, using the associated interpolated matrix and a channel estimation vector associated with the communication signal component to produce a weight vector for use in combining signals that have been despread for the communication signal component.
30. The method of claim 29, wherein said using step includes applying a Gauss-Seidel operation with respect to the channel estimation vector and the interpolated matrix to produce the associated weight vector.
31. The method of claim 22, wherein said producing step includes producing said set of data based on a set of delays.
32. The method of claim 31, including determining said delays based on information indicative of demodulation delays employed for said communication signal components.
33. The method of claim 32, wherein, for each of said communication signal components, said demodulation delays employed for said communication signal component define a subset of said set of delays.
34. The method of claim 33, wherein said set of delays is a union of said demodulation delays employed for said communication signal components.
35. The method of claim 31, wherein said set of delays is an equally spaced grid of delays, and some of said demodulation delays employed for said communication signal components are not synchronized with any of said delays.
36. The method of claim 22, wherein said set of data includes a set of correlation values associated with said interference, and including, for each of said communication signal components, using correlation values from said set to produce for the associated communication signal component a corresponding correlation matrix associated with said interference.
37. The method of claim 36, wherein said using step includes interpolating correlation values of said set.
38. The method of claim 36, including producing said correlation values by averaging correlation values that correspond to different chip sample phases.
39. The method of claim 36, wherein all of said correlation values of said set correspond to the same chip sample phase.
40. A CDMA communication receiver apparatus, comprising: an input for providing a communication signal which has been transmitted over a wireless communication link and which includes interference and a plurality of communication signal components;a plurality of signal producing units respectively associated with said communication signal components, each said signal producing unit coupled to said input for providing, in response to said communication signal, further signals that are to be combined for the associated communication signal component;a parameter estimator coupled to at least one of said signal producing units for providing a parameter estimate in response to the associated further signals; anda plurality of weight units respectively associated with said communication signal components and respectively coupled to said signal producing units, each of said weight units coupled to said parameter estimator for sharing said parameter estimate in common, each of said weight units responsive to said parameter estimate for providing for the associated communication signal component a plurality of weights for use in processing the associated further signals.
41. The apparatus of claim 40, wherein said parameter estimator is coupled to more than one of said signal producing units, said parameter estimator making initial parameter estimates in response to the further signals produced by said coupled signal producing units, and said parameter estimator producing said shared parameter estimate based on said initial parameter estimates.
42. The apparatus of claim 41, wherein said shared parameter estimate is an average of said initial parameter estimates.
43. The apparatus of claim 40, wherein said shared parameter estimate includes an estimate of one of noise power and interference power of said communication signal.
44. The apparatus of claim 40, wherein said shared parameter estimate includes estimates of noise power and interference power of said communication signal.
45. The apparatus of claim 40, wherein said signal producing unit includes a despreading unit.
46. A method for use in a CDMA communication receiver apparatus, comprising: providing a communication signal which has been transmitted over a wireless communication link and which includes interference and a plurality of communication signal components;in response to said communication signal, providing, for each of said communication signal components, further signals that are to be processed for the associated communication signal components;producing a parameter estimate in response to the further signals associated with at least one of said communication signal components;making said parameter estimate available to be shared in support of each of said communication signal components in common; andin response to said shared parameter estimate, providing for each of said communication signal components a plurality of weights for use in processing the associated further signals.
47. The apparatus of claim 1, wherein each of said signal processing paths produces filter coefficients for use by a respectively corresponding chip equalizer.
48. The method of claim 22, wherein each of said signal processing operations produces filter coefficients for use in a respectively corresponding chip equalization operation.
49. The apparatus of claim 13, wherein said set of delays is a set of predetermined delay values.
50. The apparatus of claim 49, wherein said set of delays is an equally spaced grid of delays.
51. The method of claim 31, wherein said set of delays is a set of predetermined delay values.
52. The method of claim 51, wherein said set of delays is an equally spaced grid of delays.

REDUCED COMPLEXITY INTERFERENCE SUPPRESSION FOR WIRELESS COMMUNICATIONS

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