Apparatus and method for beamforming in a changing-interference environment

• US 6,839,573 B1
• Filed: 10/31/2000
• Issued: 01/04/2005
• Est. Priority Date: 06/07/1999
• Status: Expired due to Term

• Current Assignee: Intel Corporation
• Original Assignee: ArrayComm LLC (Ygomi LLC)
• Inventors: Trott, Mitchell D., Karuppiah, Kamarai, Petrus, Paul, Youssefmir, Michael
• Primary Examiner(s): Appiah, Charles
• Assistant Examiner(s): Mehrpour, Naghmeh
• Application Number:
  US09/704,393
• Time in Patent Office: 1,526 Days
• Field of Search: 343/702, 343/757, 343/766, 342/359, 342368-384, 375/340, 375/346, 375/349, 455/362, 455/272, 455/279.1, 455/67.1, 455/423, 455/67.11, 455/67.12, 455/67.13, 455/67.14, 455/562.1, 455/114.1
• US Class Current: 455/562.1
• CPC Class Codes: H04B 7/0615 of weighted versions of same signal
• CPC Class Codes: H04B 7/0617 for beam forming
• CPC Class Codes: H04B 7/0619 using feedback from receiving side feedback signaling for adaptive modulation/coding H04L1/0001
• CPC Class Codes: H04B 7/0848 Joint weighting
• CPC Class Codes: H04B 7/0851 using training sequences or error signal minimizing error signal H04B7/0854
• CPC Class Codes: H04B 7/086 using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/021 Estimation of channel covariance
• CPC Class Codes: H04L 25/03203 Trellis search techniques
• CPC Class Codes: H04L 25/0328 with interference cancellation circuitry adaptations for interference cancellation within a sequence estimator H04L25/03305; interference related aspects of direct sequence spread spectrum H04B1/7097; interference related aspects of frequency hopping spread spectrum H04B1/715; see also H04B1/10
• CPC Class Codes: H04L 25/03299 with noise-whitening circuitry

Abstract

An apparatus and method for adaptively producing transmitted signals and processing received signals in a communication system which includes smart antenna array of antenna elements. When processing received signals, the invention modifies an existing processing scheme by incorporating information about a second set of signals for which training or other characteristic information such as a reference is unknown to information about a first set of signals for which characteristic information such as a reference is known, prior to executing the processing scheme. This approach can be used to modify the receive weights which determine the relative weight assigned to the signals received from each of a plurality of antenna elements to take into account the presence of a changing interference environment. This permits an adaptive updating of the receive weights based on the additional information provided by the second set of data, and may be accomplished faster and with less computational resources than required to determine the weights based on applying the entire processing scheme to the second set of data. In addition, assuming a relationship between the transmit and receive environment, the invention can also be used to modify the transmit weights used by the base station.

Claims

1. A method comprising:

receiving primary data for which a reference signal is available;

receiving secondary data for which a reference signal is not available;

developing a signal processing strategy based on the primary data and the available reference signal; and

incorporating information in the secondary data into the signal processing strategy to account for a changing interference environment.

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

applying the signal processing strategy to processing of one or more of an uplink and a downlink signal associated with a wireless communication system element.

3. A method according to claim 1, wherein developing the signal processing strategy and incorporating information into the signal processing strategy comprises:

combining at least a part of a feature of the secondary data with at least a part of a feature of the primary data; and

computing the signal processing strategy with the combination.

4. A method according to claim 3, wherein combining at least a part of the feature of the secondary, data with at least a part of the feature of the primary data comprises combining at least a part of the feature of the secondary data with an estimate of a feature of the primary data.

5. A method according to claim 4, wherein the estimate of the feature of the primary data includes an estimate of the covariance of the primary data.

6. A method according to claim 5, wherein the covariance estimate is represented by a noise-plus-interference-plus-signal covariance estimate.

7. A method according to claim 4, wherein the estimate of the feature of the primary data is developed using a Viterbi algorithm with branch metrics.

8. A method according to claim 3, wherein combining at least a part of the feature of the secondary data with at least a part of the feature of the primary data comprises combining a variable amount of the feature of the secondary data with at least a part of the feature of the primary data.

9. A method according to claim 8, wherein combining a variable amount of the feature of the secondary data with at least a part of the feature of the primary data comprises combining an amount of the feature of the secondary data as defined by an adjustable parameter.

10. A method according to claim 8, wherein combining a variable amount of the feature of the secondary data with at least a part of the feature of the primary data comprises combining with at least a part of the feature of the primary data a variable amount of the feature of the secondary data, wherein the feature of the secondary data accounts for aspects of an interference environment associated with the secondary data that is not associated with the primary data.

11. A method according to claim 1, wherein developing the signal processing strategy and incorporating information into the signal processing strategy comprises:

computing the signal processing strategy with the primary data;

combining at least a part of a feature of the secondary data with at least a part of a feature of the primary data; and

re-computing the signal processing strategy with the combination.

12. A method according to claim 11, further comprising:

selectively applying a set of weights for an associated number of antennae in an antenna array to one or more of signal(s) received via said antenna array or signal(s) for transmission via said antenna array.

13. A method according to claim 12, wherein each set of weights modify one or more of an amplitude and/or a phase characteristic of an uplink and/or downlink signal on an associated element of the antenna array.

14. A method according to claim 11, further comprising:

combining at least a part of a feature of tertiary data for which a reference signal is not available with the combination of at least a part of the feature of the secondary data with at least a part of the feature of the primary data; and

re-computing the signal processing strategy with the combination.

15. An article of manufacture comprising a machine-accessible medium that includes content that when accessed provides instruction to cause a machine to:

receive primary data for which a reference signal is available;

receive secondary data for which a reference signal is not available;

develop a signal processing strategy based on the primary data and the available reference signal; and

incorporate information in the secondary data into the signal processing strategy to account for a changing interference environment.

16. An article of manufacture according to claim 15, further comprising the content to provide instruction to cause the machine to:

apply the signal processing strategy to processing of one or more of an uplink and a downlink signal associated with a wireless communication system element.

17. An article of manufacture according to claim 15, wherein the content to provide instruction to cause the machine to develop the signal processing strategy and incorporate information into the signal processing strategy comprises the content to provide instructions to cause the machine to:

combine at least a part of a feature of the secondary data with at least a part of a feature of the primary data; and

compute the signal processing strategy with the combination.

18. An article of manufacture according to claim 17, wherein the content to provide instructions to cause the machine to combine at least a part of the feature of the secondary data with at least a part of the feature of the primary data comprises the content to provide instructions to cause the machine to combine at least a part of the feature of the secondary data with an estimate of a feature of the primary data.

19. An article of manufacture according to claim 18, wherein the estimate of the feature of the primary data includes an estimate of the covariance of the primary data.

20. An article of manufacture according to claim 19, wherein the covariance estimate is represented by a noise-plus-interference-plus-signal covariance estimate.

21. An article of manufacture according to claim 18, wherein the estimate of the feature of the primary data is developed using a Viterbi algorithm with branch metrics.

22. An article of manufacture according to claim 17, wherein the content to provide instructions to cause the machine to combine at least a part of the feature of the secondary data with at least a part of the feature of the primary data comprises the content to provide instructions to cause the machine to combine a variable amount of the feature of the secondary data with at least a part of the feature of the primary data.

23. An article of manufacture according to claim 22, wherein the content to provide instructions to cause the machine to combine a variable amount of the feature of the secondary data with at least a part of the feature of the primary data comprises the content to provide instructions to cause the machine to combine an amount of the feature of the secondary data as defined by an adjustable parameter.

24. An article of manufacture according to claim 22, wherein the content to provide instructions to cause the machine to combine a variable amount of the feature of the secondary data with at least a part of the feature of the primary data comprises the content to provide instructions to cause the machine to combine with at least a part of the feature of the primary data a variable amount of the feature of the secondary data, wherein the feature of the secondary data accounts for aspects of an interference environment associated with the secondary data that is not associated with the primary data.

25. An article of manufacture according to claim 15, wherein the content to provide instructions to cause the machine to develop the signal processing strategy and incorporate information into the signal processing strategy comprises the content to provide instructions to cause the machine to:

compute the signal processing strategy with the primary data;

combine at least a part of a feature of the secondary data with at least a part of a feature of the primary data; and

re-compute the signal processing strategy with the combination.

26. An article of manufacture according to claim 25, further comprising the content to provide instructions to cause the machine to:

selectively apply a set of weights for an associated number of antennae in an antenna array to one or more of signal(s) received via said antenna array or signal(s) for transmission via said antenna array.

27. An article of manufacture according to claim 26, wherein the content provides instructions to cause the machine to use each set of weights to modify one or more of an amplitude and/or a phase characteristic of an uplink and/or downlink signal on an associated element of the antenna array.

28. An article of manufacture according to claim 25, further comprising the content to provide instructions to cause the machine to:

combine at least a part of a feature of tertiary data for which a reference signal is not available with the combination of at least a part of the feature of the secondary data with at least a part of the feature of the primary data; and

re-compute the signal processing strategy with the combination.

29. An apparatus comprising:

an antenna system to receive uplink signals and transmit downlink signals; and

a processor responsive to the antenna system to receive primary data for which characteristic information is available and secondary data for which characteristic information is not available, and to develop a signal processing strategy based on the primary data and the available reference signal, and incorporate information in the secondary data into the signal processing strategy to account for a changing interference environment.

30. An apparatus according to claim 29, wherein the processor is a timeslot processor in a time-division multiple access (TDMA) communications device.

31. An apparatus according to claim 30, wherein the TDMA communications device is a wireless subscriber unit.

32. An apparatus according to claim 30, wherein the TDMA communications device is a wireless communication station.

33. An apparatus according to claim 29, wherein at least a subset of antennae within the antenna system has an associated set of weights to selectively modify one or more characteristics of an uplink signal or a downlink signal at the associated antenna.

34. An apparatus according to claim 33, wherein the set of weights selectively modifies one or more of a phase characteristic and an amplitude characteristic of a signal at the associated antenna.

35. An apparatus according to claim 34, wherein the processor includes circuitry to combine at least a part of a feature of the secondary data with at least a part of a feature of the primary data, the processor to compute a signal processing strategy with the combination.

36. An apparatus according to claim 35, wherein the circuitry combines an estimate of the feature of the primary data with at least a part of the feature of the secondary data.

37. An apparatus according to claim 36, wherein the estimate of the feature of the primary data includes an estimate of the covariance estimate of the primary data.

38. An apparatus according to claim 37, wherein the covariance estimate is represented by a noise-plus-interference-plus-signal covariance estimate.

39. An apparatus according to claim 36, wherein the estimate of the feature of the primary data is developed using a Viterbi algorithm with branch metrics.

40. An apparatus according to claim 35, wherein the circuitry combines a variable amount of the feature of the secondary data with at least a part of the feature of the primary data.

41. An apparatus according to claim 40, wherein the circuitry to combine a variable amount of the feature of the secondary data comprises the circuitry to combine an amount of the feature of the secondary data as defined by an adjustable parameter.

42. An apparatus according to claim 40, wherein the circuitry to combine a variable amount of the feature of the secondary data with at least a part of the feature of the primary data comprises the circuitry to combine a variable amount of the feature of the secondary data, wherein the secondary data accounts for aspects of an interference environment associated with the secondary data that is not associated with the primary data.