METHOD AND APPARATUS FOR DETERMINING TIMING INFORMATION FOR CELLS

• US 20120190373A1
• Filed: 01/19/2012
• Published: 07/26/2012
• Est. Priority Date: 01/20/2011
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Tenny, Nathan E.
• Granted Patent: US 9,084,191 B2
• Time in Patent Office: Days
• US Class Current: 455/447
• CPC Class Codes: H04W 56/0015 one node acting as a reference for the others

Abstract

Techniques for determining timing information for cells are disclosed. A user equipment (UE) may communicate with a serving cell and may need to make measurements of other cells, e.g., to support positioning of the UE. Each cell may transmit reference signals based on its timing. Different cells may operate asynchronously or with unknown timing. The UE may send a request for measurement gaps to the serving cell and may include timing information in the request. The timing information may (directly or indirectly) convey relative timing between the serving cell and a reference cell. The serving cell may determine measurement gaps at the proper time for other cells based on the timing information from the UE and may avoid scheduling the UE for data transmission during the measurement gaps. The UE may make measurements of other cells during the measurement gaps, without losing any data from the serving cell.

Claims

1. A method for wireless communication, comprising:

determining a first timing offset between an intermediate cell and a serving cell of a user equipment (UE);

determining a second timing offset between a reference cell and the intermediate cell; and

determining a third timing offset between the reference cell and the serving cell based on the first and second timing offsets.

2. The method of claim 1, further comprising:

determining timing information based on the third timing offset;

sending a message comprising the timing information and a request for idle periods for measurements of cells; and

receiving a measurement gap pattern determined based on the timing information.

3. The method of claim 2, further comprising:

making measurements of cells during idle periods indicated by the measurement gap pattern; and

using the measurements of cells for positioning of the UE.

4. The method of claim 1, wherein the intermediate cell is a prior serving cell of the UE, and wherein the determining the first timing offset comprises determining the first timing offset based on measurements of the serving cell made by the UE while operating on the prior serving cell.

5. The method of claim 1, wherein the UE previously camped on the intermediate cell in an idle mode, and wherein the determining the first timing offset comprises determining the first timing offset based on measurements of cells made by the UE while camping on the intermediate cell.

6. The method of claim 1, wherein the UE previously operated on the intermediate cell in a connected mode, and wherein the determining the first timing offset comprises determining the first timing offset based on measurements of cells made by the UE while in the connected mode.

7. The method of claim 1, wherein the intermediate cell is a cell previously used by the UE.

8. The method of claim 1, further comprising:

making measurements of the intermediate cell by the UE while operating on the serving cell, and wherein the determining the first timing offset comprises determining the first timing offset based on the measurements of the intermediate cell.

9. The method of claim 1, further comprising:

camping on the serving cell by the UE in an idle mode; and

making measurements of cells by the UE while in the idle mode, and wherein the determining the first timing offset comprises determining the first timing offset based on the measurements of cells.

10. The method of claim 9, wherein the making measurements comprises making measurements of cells even when the serving cell is sufficiently strong and measurements of cells for reselection are not required.

11. The method of claim 1, further comprising:

communicating with the serving cell by the UE in a connected mode; and

making measurements of the intermediate cell by the UE while in the connected mode, and wherein the determining the first timing offset comprises determining the first timing offset based on the measurements of the intermediate cell.

12. The method of claim 1, wherein the determining the first timing offset comprises

determining a subframe offset between the intermediate cell and the serving cell,

determining a radio frame offset between the intermediate cell and the serving cell, and

determining the first timing offset based on the subframe offset and the radio frame offset.

13. The method of claim 1, further comprising:

receiving system information from the intermediate cell;

determining a system frame number (SFN) of the intermediate cell based on the system information; and

determining the first timing offset based on the SFN of the intermediate cell.

14. The method of claim 1, wherein the determining the second timing offset comprises determining the second timing offset without making measurements of the reference cell by the UE.

15. The method of claim 1, wherein the determining the second timing offset comprises setting the second timing offset to zero based on the reference cell and the intermediate cell operating on a same frequency and based further on a synchronous or a semi-synchronous network deployment on the same frequency.

16. The method of claim 1, further comprising:

receiving assistance data for at least one cell including the intermediate cell, the assistance data comprising the second timing offset between the reference cell and the intermediate cell, and wherein the determining the second timing offset comprises obtaining the second timing offset from the assistance data.

17. The method of claim 1, further comprising:

receiving assistance data for at least one cell operating on a same frequency as the intermediate cell, the assistance data comprising a fourth timing offset between the reference cell and the at least one cell, and wherein the determining the second timing offset comprises setting the second timing offset equal to the fourth timing offset.

18. The method of claim 1, further comprising:

sending a message comprising the third timing offset by the UE to a designated network entity.

19. The method of claim 1, further comprising:

determining a fourth timing offset between a measurement cell and the serving cell based on the third timing offset between the reference cell and the serving cell and a fifth timing offset between the measurement cell and the reference cell; and

sending a message comprising the fourth timing offset by the UE to a designated network entity.

20. An apparatus for wireless communication, comprising:

means for determining a first timing offset between an intermediate cell and a serving cell of a user equipment (UE);

means for determining a second timing offset between a reference cell and the intermediate cell; and

means for determining a third timing offset between the reference cell and the serving cell based on the first and second timing offsets.

21. The apparatus of claim 20, further comprising:

means for determining timing information based on the third timing offset;

means for sending a message comprising the timing information and a request for idle periods for measurements of cells; and

means for receiving a measurement gap pattern determined based on the timing information.

22. The apparatus of claim 21, further comprising:

means for making measurements of cells during idle periods indicated by the measurement gap pattern; and

means for using the measurements of cells for positioning of the UE.

23. The apparatus of claim 20, wherein the intermediate cell is a prior serving cell of the UE, and wherein the means for determining the first timing offset comprises means for determining the first timing offset based on measurements of the serving cell made by the UE while operating on the prior serving cell.

24. The apparatus of claim 20, further comprising:

means for making measurements of the intermediate cell by the UE while operating on the serving cell, and wherein the means for determining the first timing offset comprises means for determining the first timing offset based on the measurements of the intermediate cell.

25. The apparatus of claim 20, wherein the means for determining the second timing offset comprises means for setting the second timing offset to zero based on the reference cell and the intermediate cell operating on a same frequency and based further on a synchronous or a semi-synchronous network deployment on the same frequency.

26. The apparatus of claim 20, further comprising:

means for receiving assistance data for at least one cell, and wherein the means for determining the second timing offset comprises means for determining the second timing offset based on the assistance data.

27. An apparatus for wireless communication, comprising:

at least one processor configured

to determine a first timing offset between an intermediate cell and a serving cell of a user equipment (UE),

to determine a second timing offset between a reference cell and the intermediate cell, and

to determine a third timing offset between the reference cell and the serving cell based on the first and second timing offsets.

28. The apparatus of claim 27, wherein the at least one processor is configured

to determine timing information based on the third timing offset,

to send a message comprising the timing information and a request for idle periods for measurements of cells, and

to receive a measurement gap pattern determined based on the timing information.

29. The apparatus of claim 28, wherein the at least one processor is configured

to make measurements of cells during idle periods indicated by the measurement gap pattern, and

to use the measurements of cells for positioning of the UE.

30. The apparatus of claim 27, wherein the intermediate cell is a prior serving cell of the UE, and wherein the at least one processor is configured

to determine the first timing offset based on measurements of the serving cell made by the UE while operating on the prior serving cell.

31. The apparatus of claim 27, wherein the at least one processor is configured

to make measurements of the intermediate cell by the UE while operating on the serving cell, and

to determine the first timing offset based on the measurements of the intermediate cell.

32. The apparatus of claim 27, wherein the at least one processor is configured to set the second timing offset to zero based on the reference cell and the intermediate cell operating on a same frequency and based further on a synchronous or a semi-synchronous network deployment on the same frequency.

33. The apparatus of claim 27, wherein the at least one processor is configured

to receive assistance data for at least one cell, and

to determine the second timing offset based on the assistance data.

34. A computer program product, comprising:

a non-transitory processor-readable medium comprising;

code for causing at least one processor to determine a first timing offset between an intermediate cell and a serving cell of a user equipment (UE),

code for causing the at least one processor to determine a second timing offset between a reference cell and the intermediate cell, and

code for causing the at least one processor to determine a third timing offset between the reference cell and the serving cell based on the first and second timing offsets.

35. A method for wireless communication, comprising:

receiving, from a user equipment (UE), timing information determined by the UE based on a timing offset between a reference cell and a serving cell of the UE;

determining a measurement gap pattern for the UE based on the timing information; and

sending the measurement gap pattern to the UE.

36. The method of claim 35, wherein the timing offset between the reference cell and the serving cell is determined based on a first timing offset between an intermediate cell and the serving cell and a second timing offset between the reference cell and the intermediate cell.

37. The method of claim 35, wherein the timing information comprises the timing offset between the reference cell and the serving cell.

38. The method of claim 35, wherein the timing information comprises a second timing offset between a measurement cell and the serving cell, the second timing offset being determined based on the timing offset between the reference cell and the serving cell.

39. The method of claim 35, wherein the determining the measurement gap pattern comprises

determining a second timing offset between a measurement cell and the serving cell based on the timing information, and

determining the measurement gap pattern based on the second timing offset.

40. An apparatus for wireless communication, comprising:

means for receiving, from a user equipment (UE), timing information determined by the UE based on a timing offset between a reference cell and a serving cell of the UE;

means for determining a measurement gap pattern for the UE based on the timing information; and

means for sending the measurement gap pattern to the UE.

41. The apparatus of claim 40, wherein the timing offset between the reference cell and the serving cell is determined based on a first timing offset between an intermediate cell and the serving cell and a second timing offset between the reference cell and the intermediate cell.

42. The apparatus of claim 40, wherein the means for determining the measurement gap pattern comprises

means for determining a second timing offset between a measurement cell and the serving cell based on the timing information, and

means for determining the measurement gap pattern based on the second timing offset.

43. An apparatus for wireless communication, comprising:

at least one processor configured

to receive, from a user equipment (UE), timing information determined by the UE based on a timing offset between a reference cell and a serving cell of the UE,

to determine a measurement gap pattern for the UE based on the timing information, and

to send the measurement gap pattern to the UE.

44. The apparatus of claim 43, wherein the timing offset between the reference cell and the serving cell is determined based on a first timing offset between an intermediate cell and the serving cell and a second timing offset between the reference cell and the intermediate cell.

45. The apparatus of claim 43, wherein the at least one processor is configured

to determine a second timing offset between a measurement cell and the serving cell based on the timing information, and

to determine the measurement gap pattern based on the second timing offset.

46. A computer program product, comprising:

a non-transitory processor-readable medium comprising;

code for causing at least one processor to receive, from a user equipment (UE), timing information determined by the UE based on a timing offset between a reference cell and a serving cell of the UE,

code for causing the at least one processor to determine a measurement gap pattern for the UE based on the timing information, and

code for causing the at least one processor to send the measurement gap pattern to the UE.