TECHNIQUES FOR EXPLICIT FEEDBACK DELAY MEASUREMENT

• US 20130230079A1
• Filed: 03/02/2012
• Published: 09/05/2013
• Est. Priority Date: 02/28/2006
• Status: Active Grant

• Current Assignee: Basson Gal, Kaidar Oren, Kasher Assaf, Myszne Jorge, Trainin B. Solomon
• Original Assignee: Basson Gal, Kaidar Oren, Kasher Assaf, Myszne Jorge, Trainin B. Solomon
• Inventors: Solomon, Trainin B., Assaf, Kasher, Oren, Kaidar, Jorge, Myszne, Gal, Basson
• Granted Patent: US 8,781,017 B2
• Time in Patent Office: Days
• US Class Current: 375/219
• CPC Class Codes: H04B 7/0413 MIMO systems
• 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 7/0626 Channel coefficients, e.g. channel state information [CSI]
• CPC Class Codes: H04B 7/0663 using vector or matrix manipulations

Abstract

Techniques for explicit feedback delay measurement are described. An apparatus may comprise a processor to generate a steering matrix for transmit spatial processing over a channel, determine a delay time associated with explicit feedback information for the channel, and determine whether to modify the steering matrix with the explicit feedback information based on the delay time. Other embodiments are described and claimed.

Claims

1-16. -16. (canceled)

17. A wireless device, comprising:

circuitry to calculate a beamforming feedback matrix for a beamformer, the circuitry to determine a time delay between a feedback request sent to a beamformee and a feedback response received from the beamformee over a multi-carrier communications channel of a wireless local area network (WLAN), the feedback response to include information to calculate the beamforming feedback matrix for transmit beamforming, the circuitry to determine whether to use the information in the feedback response to calculate the beamforming feedback matrix based on the time delay.

18. The wireless device of claim 17, the circuitry to determine to use the information in the feedback response to calculate the beamforming feedback matrix when the time delay is less than or equal to a coherence time interval of the multi-carrier communications channel.

19. The wireless device of claim 17, the circuitry to determine not to use the information in the feedback response to calculate the beamforming feedback matrix when the time delay is greater than a coherence time interval of the multi-carrier communications channel.

20. The wireless device of claim 17, the information in the feedback response to comprise channel state information (CSI) with multiple input multiple output (MIMO) channel coefficients, a non-compressed beamforming matrix, or a compressed beamforming matrix.

21. The wireless device of claim 17, the feedback request comprising a non-beamformed sounding physical layer convergence protocol (PLCP) protocol data unit (PPDU).

22. The wireless device of claim 17, the feedback request comprising a beamformed PPDU.

23. The wireless device of claim 17, the multi-carrier communications channel comprising a multiple input multiple output (MIMO) channel.

24. The wireless device of claim 17, the multi-carrier communications channel comprising part of an Institute of Electrical and Electronics Engineers (IEEE) 802.11 WLAN.

25. The wireless device of claim 17, the circuitry to comprise at least a portion of a WLAN access point (AP).

26. The wireless device of claim 17, comprising a radio frequency (RF) transceiver coupled to the circuitry to send electromagnetic representations of the feedback request and the data signal to the beamformee, and receive electromagnetic representations of the feedback response from the beamformee.

27. The wireless device of claim 26, comprising an antenna array coupled to the RF transceiver.

28. A wireless device, comprising:

circuitry to generate a feedback response for a beamformee, the circuitry to advertise feedback request capabilities to a beamformer and receive a feedback request from the beamformer over a multi-carrier communications channel of a wireless local area network (WLAN), the circuitry to generate information to calculate a beamforming feedback matrix for transmit beamforming a data signal from the beamformer to the beamformee, the information to include a time when the feedback request arrived at the beamformee.

29. The wireless device of claim 28, the circuitry to generate the feedback response to include channel state information (CSI) with multiple input multiple output (MIMO) channel coefficients.

30. The wireless device of claim 28, the circuitry to generate the feedback response to include a non-compressed beamforming matrix.

31. The wireless device of claim 28, the circuitry to generate the feedback response to include a compressed beamforming matrix.

32. The wireless device of claim 28, the feedback request comprising a non-beamformed sounding physical layer convergence protocol (PLCP) protocol data unit (PPDU).

33. The wireless device of claim 28, the feedback request comprising a beamformed PPDU.

34. The wireless device of claim 28, the multi-carrier communications channel comprising a multiple input multiple output (MIMO) channel.

35. The wireless device of claim 28, the multi-carrier communications channel comprising part of an Institute of Electrical and Electronics Engineers (IEEE) 802.11 WLAN.

36. The wireless device of claim 28, the circuitry to comprise at least a portion of a mobile device.

37. The wireless device of claim 28, comprising a radio frequency (RF) transceiver coupled to the circuitry to receive electromagnetic representations of the feedback request and the data signal from the beamformer, and send electromagnetic representations of the feedback response to the beamformer.

38. The wireless device of claim 37, comprising an antenna array coupled to the RF transceiver.

39. A method, comprising:

sending a feedback request over a wireless channel from a beamformer to a beamformee;

receiving a feedback response from the beamformee by the beamformer, the feedback response including information to calculate a beamforming feedback matrix for transmit beamforming, the feedback response including a first timestamp of when the feedback request arrived at the beamformee;

determining a second timestamp of when the feedback response arrived at the beamformer;

calculating a time delay as the second timestamp minus the first timestamp; and

determining whether to use the information in the feedback response to form or modify the beamforming feedback matrix for transmit beamforming a data signal from the beamformer to the beamformee based on the time delay.

40. The method of claim 39, comprising beamforming a data signal from the beamformer to the beamformee using the information in the feedback response when the time delay is less than or equal to a coherence time interval of the wireless channel.

41. The method of claim 39, comprising discarding the information in the feedback response when the time delay is greater than a coherence time interval of the wireless channel.

42. The method of claim 39, the information in the feedback response comprising channel state information (CSI) including multiple input multiple output (MIMO) channel coefficients.

43. The method of claim 39, the information in the feedback response comprising a non-compressed beamforming matrix or a compressed beamforming matrix.

44. The method of claim 39, the feedback request comprising a non-beamformed sounding physical layer convergence protocol (PLCP) protocol data unit (PPDU).

45. The method of claim 39, the feedback request comprising a beamformed PPDU.

46. The method of claim 39, the wireless channel comprising a multi-carrier communications channel of an Institute of Electrical and Electronics Engineers (IEEE) 802.11 wireless local area network (WLAN).