Receiver techniques for wireless communication

• US 20070071070A1
• Filed: 09/29/2005
• Published: 03/29/2007
• Est. Priority Date: 09/29/2005
• Status: Active Grant

• Current Assignee: LGS Innovations LLC (CACI International Incorporated)
• Original Assignee: Alcatel-Lucent USA, Inc. (Nokia Corporation)
• Inventors: Mardani, Reza, Dominique, Francis, Mailaender, Laurence, Mullany, Francis
• Granted Patent: US 7,894,514 B2
• Time in Patent Office: Days
• US Class Current: 375/147
• CPC Class Codes: H04B 1/7115 Constructive combining of multi-path signals, i.e. RAKE receivers
• CPC Class Codes: H04L 2025/03585 Modifying the length
• CPC Class Codes: H04L 25/03019 adaptive, i.e. capable of adjustment during data reception

Abstract

A receiver device for use in a wireless communication system (20) includes a rake receiver (32) and an equalizer receiver (34). A controller (36) selects one of the rake receiver (32) or the equalizer receiver (34) for processing a received signal. In some situations, the rake receiver (32) will provide better performance. In other situations, the equalizer receiver (34) will provide better performance. One embodiment includes a plurality of equalizers (34A, 34B). One of the equalizers processes a data packet from a received signal while another one of the equalizers trains for processing a signal from a subsequent scheduled user. Another example embodiment includes controlling an equalizer length based on a delay span or another selected channel metric.

Claims

1-19. -19. (canceled)

20. A method of communicating using a base station having an equalizer receiver and a rake receiver, comprising:

selecting one of the equalizer receiver or the rake receiver for processing a received signal.

21. The method of claim 20, comprising determining whether the equalizer receiver or the rake receiver will provide better performance for a given received signal and selecting the one of the equalizer receiver or the rake receiver that will provide the better performance.

22. The method of claim 21, comprising determining a performance metric associated with processing the received signal using each of the equalizer receiver and the rake receiver and selecting the one of the equalizer receiver or the rake receiver based upon the determined associated performance metric.

23. The method of claim 22, comprising determining an error energy associated with each of the equalizer receiver and the rake receiver and selecting the one of the equalizer receiver or the rake receiver that has a lower associated error energy.

24. The method of claim 23, comprising

receiving a pilot signal from a source of the received signal;

determining a difference between the received pilot signal and a corresponding expected pilot signal; and

squaring the determined difference to thereby determine the error energy.

25. The method of claim 20, comprising

using a plurality of equalizers;

training at least a first one of the plurality of equalizers during a current packet interval for adapting an equalizer technique to correspond to an expected signal; and

processing a received signal using a second one of the plurality of equalizers during the current packet interval.

26. The method of claim 20, comprising

using an equalizer having an equalizer length;

determining a selected characteristic of a channel used for communicating at least one signal to the equalizer; and

determining a desired value for the equalizer length corresponding to the determined characteristic.

27. A method of communicating using a plurality of equalizers, comprising:

training at least a first one of the plurality of equalizers during a current packet interval for adapting an equalizer technique to correspond to an expected signal; and

processing a received signal using a second one of the plurality of equals during the current packet interval.

28. The method of claim 27, comprising

training the second one of the plurality of equalizers during a subsequent packet interval for adapting an equalizer technique to correspond to a subsequently expected signal;

receiving the expected signal during the subsequent packet interval; and

processing the received, expected signal using the trained first one of the plurality of equalizers during the subsequent packet interval.

29. The method of claim 27, comprising

performing the training during K packet intervals, wherein K≧

1 and there are K+1 equalizers in the plurality; and

training K of the plurality of equalizers during the current packet interval.

30. The method of claim 27, comprising

providing information from the first one of the plurality of equalizers to the second one of the plurality of equalizers regarding the training during the current packet interval;

adapting the equalizer technique of the second one of the plurality of equalizers using the provided information; and

processing the received, expected signal using the adapted equalizer technique of the second one of the plurality of equalizers during the subsequent packet interval.

31. The method of claim 27, comprising at least one of

adapting the equalizer technique of the second one of the plurality of equalizers prior to the current packet interval;

or

adapting the equalizer technique of the second one of the plurality of equalizers during the current packet interval.

32. The method of claim 27, comprising selecting one of an equalizer technique or a rake receiver technique for processing a received signal.

33. The method of claim 27, comprising

using an equalizer having an equalizer length;

determining a selected characteristic of a channel used for communicating at least one signal to the equalizer; and

determining a desired value for the equalizer length corresponding to the determined characteristic.

34. A method of communicating using an equalizer having an equalizer length, comprising

determining a selected characteristic of a channel used for communicating at least one signal to the equalizer;

and

determining a desired value for the equalizer length corresponding to the determined characteristic.

35. The method of claim 34, comprising determining a delay span of the channel as the selected characteristic.

36. The method of claim 34, comprising determining the delay span by determining an impulse response on the channel.

37. The method of claim 34, comprising

predetermining a plurality of equalizer lengths that each correspond to one of a plurality of values of the selected characteristic;

and

selecting one of the plurality of equalizer lengths responsive to determining the selected characteristic.

38. The method of claim 34, comprising selecting one of an equalizer technique or a rake receiver technique for processing a received signal.

39. The method of claim 34, comprising

using a plurality of equalizers;

training at least a first one of the plurality of equalizers during a current packet interval for adapting an equalizer technique to correspond to an expected signal; and

processing a received signal using a second one of the plurality of equalizers during the current packet interval.