METHOD AND APPARATUS FOR MULTIPLE USER UPLINK REQUIRING MINIMAL STATION TIMING AND FREQUENCY SYNCHRONIZATION

• US 20100329236A1
• Filed: 08/26/2009
• Published: 12/30/2010
• Est. Priority Date: 06/26/2009
• Status: Abandoned Application

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Jones, Vincent Knowles IV, Vermani, Sameer, Sampath, Hemanth, Abraham, Santosh P.
• Application Number:
  US12/548,081
• Publication Number:
  US 20100329236A1
• Time in Patent Office: Days
• US Class Current: 370/350
• CPC Class Codes: H04B 7/0452 Multi-user MIMO systems
• CPC Class Codes: H04W 56/0005 synchronizing of arrival of multiple uplinks
• CPC Class Codes: H04W 56/0035 detecting errors in frequency or phase

Abstract

An apparatus is disclosed having a receiver configured to receive correction information; and a transmitter configured to transmit data based on the correction information through one or more antennas to one or more nodes. A method for wireless communications is also disclosed. The method includes sending correction information to a plurality of wireless nodes; receiving corrected data generated by at least one station of the plurality of wireless nodes based on the correction information; and spatially processing the corrected data.

Claims

1. A method for wireless communications comprising:

sending correction information to a plurality of wireless nodes;

receiving corrected data generated by at least one wireless node of the plurality of wireless nodes based on the correction information; and

spatially processing the corrected data.

2. The method of claim 1, wherein the sending of the correction information to the plurality of wireless nodes comprises requesting at least one wireless node in the plurality of wireless nodes to correct a frequency offset in a first communication based on a frequency offset estimate determined during a second communication.

3. The method of claim 2, wherein the second communication comprises at least one of a preamble or a pilot, and the at least one wireless node estimates the frequency offset based on the at least one of the preamble and the pilot.

4. The method of claim 1, wherein the sending of the correction information to the plurality of wireless nodes comprises requesting at least one wireless node in the plurality of wireless nodes to correct a frequency offset in a communication based on a frequency offset estimate determined during a previous communication from the at least one wireless node.

5. The method of claim 1, wherein the sending of the correction information to the plurality of wireless nodes comprises requesting at least one wireless node to correct power in a first communication based on a power estimate determined by the at least one wireless node in a second communication.

6. The method of claim 5, wherein the power estimate is based on a preamble in a packet from the second communication.

7. The method of claim 1, further comprising transmitting a request for uplink information to the plurality of wireless nodes.

8. The method of claim 7, wherein the request for uplink information comprises a reservation of a transmission medium to be used to receive at least one response to the request.

9. The method of claim 7, wherein the request for uplink information is transmitted using a backoff procedure.

10. The method of claim 1, further comprising selecting the plurality of wireless nodes based on a QoS requirement of at least one of the wireless nodes.

11. The method of claim 1, wherein the correction information comprises at least one of frequency, time or power correction information.

12. The method of claim 11, wherein the timing correction information comprises a request for at least one of the plurality of wireless nodes to use an extended cyclic prefix.

13. The method of claim 11, further comprising determining the power correction information based on a backoff power value.

14. The method of claim 11, further comprising determining the frequency correction information for a wireless node from a plurality of sounding frames sent by that wireless node.

15. The method of claim 14, wherein each sounding frame in the plurality of sounding frames was transmitted as part of a CTS frame that was also transmitted by each of the wireless nodes.

16. The method of claim 14, further comprising transmitting an acknowledgement message in an MU-MIMO fashion based on a channel estimate calculated from the plurality of sounding frames.

17. The method of claim 16, further comprising modifying the channel estimate based on channel state information before the acknowledgement transmission.

18. The method of claim 1, wherein the corrected data are received simultaneously from at least two of the plurality of wireless nodes.

19. An apparatus for wireless communications, comprising:

a processing system configured to;

send correction information to a plurality of wireless nodes;

receive corrected data generated by at least one wireless node of the plurality of wireless nodes based on the correction information; and

spatially process the corrected data.

20. The apparatus of claim 19, wherein the processing system is further configured to request at least one wireless node in the plurality of wireless nodes to correct a frequency offset in a first communication based on a frequency offset estimate determined during a second communication.

21. The apparatus of claim 20, wherein the second communication comprises at least one of a preamble and a pilot, and the at least one wireless node estimates the frequency offset based on the at least one of the preamble and the pilot.

22. The apparatus of claim 19, wherein the sending of the correction information to the plurality of wireless nodes comprises requesting at least one wireless node in the plurality of wireless nodes to correct a frequency offset in a communication based on a frequency offset estimate determined during a previous communication from the at least one wireless node.

23. The apparatus of claim 19, wherein the processing system is further configured to request at least one wireless node to correct power in a first communication based on a power estimate determined by the at least one wireless node in a second communication.

24. The apparatus of claim 23, wherein the power estimate is based on a preamble in a packet from the second communication.

25. The apparatus of claim 19, wherein the processing system is further configured to transmit a request for uplink information to the plurality of wireless nodes.

26. The apparatus of claim 25, wherein the request for uplink information comprises a reservation of a transmission medium used to receive at least one response to the request.

27. The apparatus of claim 25, wherein the request for uplink information is transmitted using a backoff procedure.

28. The apparatus of claim 19, further comprising selecting the plurality of wireless nodes based on a QoS requirement of at least one of the wireless nodes.

29. The apparatus of claim 19, wherein the correction information comprises at least one of frequency, time and power correction information.

30. The apparatus of claim 29, wherein the timing correction information comprises a request for at least one of the plurality of wireless nodes to use an extended cyclic prefix.

31. The apparatus of claim 29, wherein the processing system is further configured to determine the power correction information based on a backoff power value.

32. The apparatus of claim 29, wherein the processing system is further configured to determine the frequency correction information for a wireless node from a plurality of sounding frames sent by that wireless node.

33. The apparatus of claim 32, wherein each sounding frame in the plurality of sounding frames was transmitted as part of a CTS frame that was also transmitted by each of the wireless nodes.

34. The apparatus of claim 32, wherein the processing system is further configured to transmit an acknowledgement message in an MU-MIMO fashion based on a channel estimate calculated from the plurality of sounding frames.

35. The apparatus of claim 34, wherein the processing system is further configured to modify the channel estimate based on channel state information before the acknowledgement transmission.

36. The apparatus of claim 19, wherein the corrected data are received simultaneously from at least two of the plurality of wireless nodes.

37. An apparatus for wireless communications, comprising:

means for sending correction information to a plurality of wireless nodes;

means for receiving corrected data generated by at least one wireless node of the plurality of wireless nodes based on the correction information; and

means for spatially processing the corrected data.

38. The apparatus of claim 37, wherein the means for sending the correction information to the plurality of wireless nodes comprises means for requesting at least one wireless node in the plurality of wireless nodes to correct a frequency offset in a first communication based on a frequency offset estimate determined during a second communication.

39. The apparatus of claim 38, wherein the second communication comprises at least one of a preamble and a pilot, and the at least one wireless node estimates the frequency offset based on the at least one of the preamble and the pilot.

40. The apparatus of claim 37, wherein the means for sending the correction information to the plurality of wireless nodes comprises means for requesting at least one wireless node in the plurality of wireless nodes to correct a frequency offset in a communication based on a frequency offset estimate determined during a previous communication from the at least one wireless node.

41. The apparatus of claim 37, wherein the means for sending the correction information to the plurality of wireless nodes comprises means for requesting at least one wireless node to correct power in a first communication based on a power estimate determined by the at least one wireless node in a second communication.

42. The apparatus of claim 41, wherein the power estimate is based on a preamble in a packet from the second communication.

43. The apparatus of claim 37, further comprising transmitting a request for uplink information to the plurality of wireless nodes.

44. The apparatus of claim 43, wherein the request for uplink information comprises a reservation of a transmission medium used to receive at least one response to the request.

45. The apparatus of claim 43, wherein the request for uplink information is transmitted using a backoff procedure.

46. The apparatus of claim 37, further comprising selecting the plurality of wireless nodes based on a QoS requirement of at least one of the wireless nodes.

47. The apparatus of claim 37, wherein the correction information comprises at least one of frequency, time and power correction information.

48. The apparatus of claim 47, wherein the timing correction information comprises a request for at least one of the plurality of wireless nodes to use an extended cyclic prefix.

49. The apparatus of claim 47, further comprising means for determining the power correction information based on a backoff power value.

50. The apparatus of claim 47, further comprising means for determining the frequency correction information for a wireless node from a plurality of sounding frames sent by that wireless node.

51. The apparatus of claim 50, wherein each sounding frame in the plurality of sounding frames was transmitted as part of a CTS frame that was also transmitted by each of the wireless nodes.

52. The apparatus of claim 50, further comprising transmitting an acknowledgement message in an MU-MIMO fashion based on a channel estimate calculated from the plurality of sounding frames.

53. The apparatus of claim 52, further comprising modifying the channel estimate based on channel state information before the acknowledgement transmission.

54. The apparatus of claim 37, wherein the corrected data are received simultaneously from at least two of the plurality of wireless nodes.

55. A computer-program product for wireless communications, comprising:

a machine-readable medium comprising instructions executable to;

send correction information to a plurality of wireless nodes;

receive corrected data generated by at least one wireless node of the plurality of wireless nodes based on the correction information; and

spatially process the corrected data.

56. An access point, comprising:

one or more antennas;

a transmitter configured to send, via the one or more antennas, correction information through the antennas to a plurality of wireless nodes;

a receiver configured to receive corrected data generated by at least one wireless node of the plurality of wireless nodes based on the correction information; and

a processor configured to spatially process the corrected data.

57. A method for wireless communications comprising:

receiving correction information; and

transmitting data based on the correction information.

58. The method of claim 57, wherein the correction information comprises at least one of frequency, time or power correction information.

59. The method of claim 58, wherein the correction information further comprises at least one of buffer size, QoS requirement, delay requirement or latency requirement

60. The method of claim 58, further comprising transmitting a sounding frame to allow the frequency correction information to be determined.

61. The method of claim 60, further comprising transmitting a CTS frame before the sounding frame.

62. The method of claim 61, further comprising providing a reduced interframe spacing between the CTS frame and at least one sounding frame transmissions.

63. The method of claim 61, further comprising providing a short interframe spacing before the CTS frame transmission.

64. The method of claim 60, wherein the sounding frame comprises a training portion comprising of a short training field and a long training field.

65. The method of claim 57, wherein the data are transmitted using an extended cyclic prefix.

66. The method of claim 58, further comprising performing frequency correction based on the correction information, wherein the frequency correction is performed in a digital domain.

67. An apparatus for wireless communications, comprising:

a processing system configured to;

receive correction information; and

transmit data based on the correction information.

68. The apparatus of claim 67, wherein the correction information comprises at least one of frequency, time and power correction information.

69. The apparatus of claim 68, wherein the correction information further comprises at least one of buffer size, QoS requirement, delay requirement or latency requirement.

70. The apparatus of claim 68, wherein the processing system is further configured to transmit a sounding frame to allow the frequency correction information to be determined.

71. The apparatus of claim 70, wherein the processing system is further configured to transmit a CTS frame before the sounding frame.

72. The apparatus of claim 71, wherein the processing system is further configured to provide a reduced interframe spacing between the CTS frame and at least one sounding frame transmissions.

73. The apparatus of claim 71, wherein the processing system is further configured to provide a short interframe spacing before the CTS frame transmission.

74. The apparatus of claim 70, wherein the sounding frame comprises a training portion comprising of a short training field and a long training field.

75. The apparatus of claim 67, wherein the data are transmitted using an extended cyclic prefix.

76. The apparatus of claim 68, wherein the processing system is further configured to perform frequency correction based on the correction information, wherein the frequency correction is performed in a digital domain.

77. An apparatus for wireless communications, comprising:

means for receiving correction information; and

means for transmitting data based on the correction information.

78. The apparatus of claim 77, wherein the correction information comprises at least one of frequency, time or power correction information.

79. The apparatus of claim 78, wherein the correction information further comprises at least one of buffer size, QoS requirement, delay requirement or latency requirement.

80. The apparatus of claim 78, further comprising means for transmitting a sounding frame to allow the frequency correction information to be determined.

81. The apparatus of claim 80, further comprising means for transmitting a CTS frame before the sounding frame.

82. The apparatus of claim 81, further comprising means for providing a reduced interframe spacing between the CTS frame and at least one sounding frame transmissions.

83. The apparatus of claim 80, further comprising means for providing a short interframe spacing before the CTS frame transmission.

84. The apparatus of claim 80, wherein the sounding frame comprises a training portion comprising of a short training field and a long training field.

85. The apparatus of claim 77, wherein the data are transmitted using an extended cyclic prefix.

86. The apparatus of claim 78, further comprising means for performing frequency correction based on the correction information, wherein the frequency correction is performed in a digital domain.

87. A computer-program product for wireless communications, comprising:

a machine-readable medium comprising instructions executable to;

receive correction information; and

transmit data based on the correction information.

88. A mobile station, comprising:

one or more antennas;

a receiver configured to receive, via the one or more antennas, correction information; and

a transmitter configured to transmit data based on the correction information.

89. An electronic card, comprising:

a receiver configured to receive correction information; and

a transmitter configured to transmit data based on the correction information through one or more antennas to one or more nodes.