REPORTING OF TIMING INFORMATION TO SUPPORT DOWNLINK DATA TRANSMISSION

• US 20110085460A1
• Filed: 10/12/2010
• Published: 04/14/2011
• Est. Priority Date: 10/13/2009
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Luo, Tao, Zhang, Xiaoxia
• Granted Patent: US 8,948,028 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04B 7/024 Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems
• CPC Class Codes: H04W 56/005 compensating for timing error by adjustment in the receiver

Abstract

Techniques for reporting timing information to facilitate data transmission on a downlink are described. A user equipment (UE) may receive signals from a plurality of cells available for data transmission to the UE. Each cell may have a different propagation delay to the UE. The UE may determine timing information based on the received signals and may report the timing information to one or more of the cells. The timing information may include a receive time of each cell at the UE. The UE may receive a data transmission from at least one cell, which can be selected from the plurality of cells, based on the timing information. The at least one cell may provide a coordinated or a non-coordinated data transmission. A coordinated transmission mode may be determined based on the timing information and can include, for example, a joint transmission, a coordinated beamforming, or a coordinated silencing.

Claims

1. A method for wireless communication, comprising:

receiving at a user equipment (UE) signals from a plurality of cells available for data transmission to the UE;

determining timing information for the plurality of cells based on the received signals;

sending the timing information for the plurality of cells; and

receiving a data transmission from at least one cell in the plurality of cells determined based on the timing information.

2. The method of claim 1, wherein the data transmission comprises a coordinated transmission or a non-coordinated transmission.

3. The method of claim 2, wherein the coordinated transmission comprises a joint transmission, a coordinated beamforming, or a coordinated silencing by cells in the plurality of cells.

4. The method of claim 1, wherein the data transmission is received from multiple cells and each of the multiple cells has a receive time within a timing window at the UE.

5. The method of claim 1, wherein the data transmission is received from a single cell.

6. The method of claim 1, wherein the data transmission is associated with a second data transmission from at least one other cell in the plurality of cells, the second data transmission comprising a coordinated beamforming based at least in part on the timing information.

7. The method of claim 6, wherein the at least one other cell has a receive time outside a timing window at the UE.

8. The method of claim 1, wherein the data transmission is associated with a coordinated silencing of at least one other cell in the plurality of cells, and wherein the coordinated silencing is based at least in part on the timing information.

9. The method of claim 1, wherein the determining the timing information comprises:

determining a receive time of each of the plurality of cells at the UE, and

determining the timing information based on receive times of the plurality of cells at the UE.

10. The method of claim 9, wherein the determining the receive time of each of the plurality of cells comprises:

determining the receive time of each cell based on a first arriving path, or a strongest path, or a center of mass of a channel impulse response for the cell.

11. The method of claim 9, wherein the timing information comprises an indication of whether the receive time of each of the plurality of cells is within a timing window at the UE.

12. The method of claim 11, wherein the timing window has a width determined based on a cyclic prefix of the received signals.

13. The method of claim 1, wherein the determining the timing information comprises

determining a reference time,

determining a receive time of each of the plurality of cells at the UE,

determining a time difference for each of the plurality of cells based on the receive time of the cell and the reference time, and

determining the timing information based on time differences for the plurality of cells.

14. The method of claim 13, wherein the determining the reference time comprises determining the reference time based on a first arriving path, or a strongest path, or a center of mass of a channel impulse response for a designated cell among the plurality of cells.

15. The method of claim 13, wherein the determining the reference time comprises determining the reference time based on a first arriving path, or a strongest path, or a center of mass of a composite channel impulse response for at least two cells among the plurality of cells.

16. The method of claim 1, wherein the reporting the timing information comprises reporting the timing information to a serving cell in a coordinated multi-point transmission (CoMP) set.

17. The method of claim 1, further comprising:

reporting channel state information for the plurality of cells by the UE for use for data transmission to the UE.

18. The method of claim 17, further comprising:

generating a feedback report comprising the channel state information and the timing information for the plurality of cells; and

sending the feedback report by the UE.

19. An apparatus for wireless communication, comprising:

means for receiving signals from a plurality of cells available for data transmission;

means for determining timing information for the plurality of cells based on the received signals;

means for sending the timing information for the plurality of cells; and

means for receiving a data transmission from at least one cell in the plurality of cells determined based on the timing information.

20. The apparatus of claim 19, wherein the data transmission comprises a coordinated transmission or a non-coordinated transmission.

21. The apparatus of claim 20, wherein the coordinated transmission comprises a joint transmission, a coordinated beamforming, or a coordinated silencing by cells in the plurality of cells.

22. The apparatus of claim 19, wherein the means for determining the timing information comprises:

means for determining a receive time of each of the plurality of cells at the UE, and

means for determining the timing information based on receive times of the plurality of cells at the UE.

23. The apparatus of claim 22, wherein the means for determining the receive time comprises:

means for determining the receive time of each cell based on a first arriving path, or a strongest path, or a center of mass of a channel impulse response for the cell.

24. The apparatus of claim 19, wherein the means for determining the timing information comprises

means for determining a reference time,

means for determining a receive time of each of the plurality of cells at the UE,

means for determining a time difference for each of the plurality of cells based on the receive time of the cell and the reference time, and

means for determining the timing information based on time differences for the plurality of cells.

25. The apparatus of claim 19, further comprising:

means for determining channel state information for the plurality of cells by the UE;

means for generating a feedback report comprising the channel state information and the timing information for the plurality of cells; and

means for sending the feedback report by the UE.

26. An apparatus for wireless communication, comprising:

at least one processor configured to;

receive signals from a plurality of cells available for data transmission,

determine timing information for the plurality of cells based on the received signals;

report the timing information for the plurality of cells, and

receive a data transmission from at least one cell in the plurality of cells determined based on the timing information.

27. The apparatus of claim 26, wherein the data transmission comprises a coordinated transmission or a non-coordinated transmission.

28. The apparatus of claim 27, wherein the coordinated transmission comprises a joint transmission, a coordinated beamforming, or a coordinated silencing by cells in the plurality of cells.

29. The apparatus of claim 26, wherein the at least one processor is configured to:

determine a receive time of each of the plurality of cells at the UE, and

determine the timing information based on receive times of the plurality of cells at the UE.

30. The apparatus of claim 29, wherein the at least one processor is configured to determine the receive time of each cell based on a first arriving path, or a strongest path, or a center of mass of a channel impulse response for the cell.

31. The apparatus of claim 26, wherein the at least one processor is configured to:

determine a reference time,

determine a receive time of each of the plurality of cells at the UE,

determine a time difference for each of the plurality of cells based on the receive time of the cell and the reference time, and

determine the timing information based on time differences for the plurality of cells.

32. The apparatus of claim 26, wherein the at least one processor is configured to:

determine channel state information for the plurality of cells by the UE,

generate a feedback report comprising the channel state information and the timing information for the plurality of cells, and

send the feedback report by the UE.

33. A computer program product, comprising:

a non-transitory computer-readable medium comprising;

code for causing at least one computer to receive signals from a plurality of cells available for data transmission to a user equipment (UE),

code for causing the at least one computer to determine timing information for the plurality of cells based on the received signals,

code for causing the at least one computer to report the timing information for the plurality of cells by the UE, and

code for causing the at least one computer to receive a data transmission from at least one cell in the plurality of cells determined based on the timing information for the plurality of cells.

34. A method for wireless communication, comprising:

receiving timing information for a plurality of cells from a user equipment (UE);

determining a data transmission comprising a coordinated data transmission or a non-coordinated data transmission based on the timing information; and

sending data from one or more cells in the plurality of cells as part of the data transmission.

35. The method of claim 34, further comprising:

determining one or more cells to participate in the data transmission based on the timing information.

36. The apparatus of claim 35, further comprising determining a coordinated transmission mode for the UE based on the timing information.

37. The method of claim 36, wherein the coordinated transmission mode comprises a joint transmission, a coordinated beamforming, or a coordinated silencing by cells in the plurality of cells.

38. The method of claim 34, wherein the one or more cells comprise a plurality of cells selected to participate in the data transmission, and wherein each of the plurality of cells selected to participate in the data transmission has a receive time within a timing window at the UE.

39. The method of claim 34, further comprising:

determining at least one cell in the plurality of cells to perform a coordinated beamforming for the UE, the at least one cell having a receive time outside a timing window at the UE.

40. The method of claim 34, further comprising:

determining at least one cell in the plurality of cells to perform a coordinated silencing for the UE.

41. The method of claim 34, wherein the determining the one or more cells to participate in the data transmission comprises:

determining whether a receive time associated with a corresponding signal is within a timing window at the UE, and

selecting the one or more cells from among cells having receive times within the timing window.

42. The method of claim 34, wherein the determining the one or more cells to participate in the data transmission comprises:

obtaining a time difference for each of the plurality of cells from the timing information, the time difference for each cell being determined based on a receive time of the cell at the UE and a reference time, and selecting the one or more cells based at least on the time differences.

43. The method of claim 34, further comprising:

receiving channel state information for the plurality of cells from the UE, and

wherein the sending the data transmission comprises sending the data transmission from the one or more cells based on the channel state information.

44. An apparatus for wireless communication, comprising:

means for receiving timing information for a plurality of cells from a user equipment (UE);

means for determining a data transmission comprising a coordinated data transmission or a non-coordinated data transmission based on the timing information; and

means sending data from one or more cells in the plurality of cells as part of the data transmission.

45. The apparatus of claim 44, further comprising:

means for determining one or more cells to participate in the data transmission based on the timing information.

46. The apparatus of claim 44, further comprising:

means for determining a coordinated transmission mode for the UE based on the timing information.

47. The apparatus of claim 46, wherein the coordinated transmission mode comprises a joint transmission, a coordinated beamforming, or a coordinated silencing by cells in the plurality of cells.

48. The apparatus of claim 44, wherein the means for determining the one or more cells comprise:

means for determining whether a receive time of each of the plurality of cells is within a timing window at the UE based on the timing information, and

means for selecting the one or more cells from the cells having with receive times within the timing window.

49. The apparatus of claim 44, wherein the means for determining the one or more cells comprise:

means for obtaining a time difference for each of the plurality of cells from the timing information, the time difference for each cell being determined based on a receive time of the cell at the UE and a reference time, and

means for selecting the one or more cells based at least on time differences for the plurality of cells.

50. The apparatus of claim 44, further comprising:

means for receiving channel state information for the plurality of cells from the UE, and wherein the means for sending the data transmission comprises means for sending the data transmission from the one or more cells based on the channel state information.

51. An apparatus for wireless communication, comprising:

at least one processor configured to;

receive timing information for a plurality of cells from a user equipment (UE);

determine a data transmission comprising a coordinated data transmission or a non-coordinated data transmission based on the timing information; and

send data from one or more cells in the plurality of cells as part of the data transmission.

52. The apparatus of claim 51, wherein the at least one processor is configured to determine one or more cells to participate in the data transmission based on the timing information.

53. The apparatus of claim 51, wherein the at least one processor is configured to determine a coordinated transmission mode for the UE based on the timing information.

54. The apparatus of claim 53, wherein the coordinated transmission mode comprises a joint transmission, a coordinated beamforming, or a coordinated silencing by cells in the plurality of cells.

55. The apparatus of claim 51, wherein the at least one processor is configured to:

determine whether a receive time of each of the plurality of cells is within a timing window at the UE based on the timing information, and

select the one or more cells from among all cells having receive times within the timing window.

56. The apparatus of claim 51, wherein the at least one processor is configured to:

obtain a time difference for each of the plurality of cells from the timing information, the time difference for each cell being determined based on a receive time of the cell at the UE and a reference time, and

select the one or more cells based at least on time differences for the plurality of cells.

57. The apparatus of claim 51, wherein the at least one processor is configured to:

receive channel state information for the plurality of cells from the UE, and

send the data transmission from the one or more cells based on the channel state information.

58. A computer program product, comprising:

a non-transitory computer-readable medium comprising;

code for causing at least one computer to receive timing information for a plurality of cells from a user equipment (UE);

code for causing the at least one computer to determine a data transmission comprising a coordinated data transmission or a non-coordinated data transmission based on the timing information;

code for causing the at least one computer to determine one or more cells to participate in the data transmission based on the timing information; and

code for causing the at least one computer to send data from the one or more cells to the UE as part of the data transmission.