Method and Apparatus for Returning During a Baton Handover

• US 20120172043A1
• Filed: 03/31/2010
• Published: 07/05/2012
• Est. Priority Date: 09/22/2009
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Chin, Tom, Shi, Guangming, Lee, Kuo-Chun
• Granted Patent: US 9,094,883 B2
• Time in Patent Office: Days
• US Class Current: 455/436
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 36/0072 of resource information of target access point
• CPC Class Codes: H04W 36/0079 in case of hand-off failure or rejection
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/28 involving a plurality of connections, e.g. multi-call or multi-bearer connections
• CPC Class Codes: H04W 48/20 Selecting an access point
• CPC Class Codes: H04W 72/541 using the level of interference
• CPC Class Codes: H04W 92/20 between access points

Abstract

An apparatus and method enable mobile user equipment to return to a first cell after attempting a baton handover to a second cell. In one aspect of the disclosure, a method of wireless communication in a cellular network including a source cell and a target cell is disclosed. Here, the method includes switching transmission of an uplink from the source cell to the target cell while maintaining a downlink with the source cell, determining to return the transmission of the uplink to the source cell, and returning the transmission of the uplink from the target cell to the source cell. In some aspects, the method may further include switching reception of a downlink from the source cell to the target cell, determining to return the reception of the downlink to the source cell, and returning the reception of the downlink from the target cell to the source cell.

Claims

1. A method of wireless communication in a cellular network comprising a source cell and a target cell, the method comprising:

switching transmission of an uplink from the source cell to the target cell while maintaining a downlink with the source cell;

determining to return the transmission of the uplink to the source cell; and

returning the transmission of the uplink from the target cell to the source cell.

2. The method of claim 1, wherein the determining to return the transmission of the uplink to the source cell comprises determining a failure of the uplink to the target cell.

3. The method of claim 2, wherein the determining the failure of the uplink to the target cell comprises determining, at an expiration of a timer corresponding to the switching the transmission of the uplink from the source cell to the target cell, that the uplink to the target call was not acquired.

4. The method of claim 2, wherein the determining the failure of the uplink to the target cell comprises determining that an error rate of the uplink is higher than a threshold error rate.

5. The method of claim 1, wherein the determining to return the transmission of the uplink to the source cell comprises determining that at least one of a signal strength or a SINR of the downlink has increased, or that an error rate of the downlink has decreased.

6. The method of claim 1, further comprising:

switching reception of a downlink from the source cell to the target cell;

determining to return the reception of the downlink to the source cell; and

returning the reception of the downlink from the target cell to the source cell.

7. The method of claim 6, wherein the determining to return the reception of the downlink to the source cell comprises determining a failure of the downlink from the target cell.

8. The method of claim 7, wherein the determining the failure of the downlink from the target cell comprises determining that at least one of a signal strength or a SINR of the downlink is lower than a threshold, or that an error rate is higher than an error threshold.

9. The method of claim 7, wherein the determining the failure of the downlink from the target cell comprises determining, at an expiration of a timer corresponding to the switching the transmission of the downlink from the source cell to the target cell, that the downlink from the target cell was not acquired.

10. The method of claim 6, wherein, when a location of a user equipment utilizing the uplink and the downlink, or a metric of quality of the downlink, are substantially the same since a time when the switching the transmission of the uplink began, the returning the reception of the downlink from the target cell to the source cell comprises first returning the transmission of the uplink from the target cell to the source cell, and subsequently returning the reception of the downlink from the target cell to the source cell.

11. The method of claim 10, wherein the metric of quality of the downlink comprises a received signal strength corresponding to the downlink and a delay in the downlink.

12. The method of claim 6, wherein, when a location of a user equipment utilizing the uplink and the downlink, and a metric of quality of the downlink, have changed by an amount greater than respective predetermined thresholds, the returning the reception of the downlink from the target cell to the source cell comprises returning the transmission of the uplink and the reception of the downlink from the target cell to the source cell at substantially the same time.

13. The method of claim 12, wherein the metric of quality of the downlink comprises a received signal strength corresponding to the downlink and a delay in the downlink.

14. The method of claim 1, wherein the switching the transmission of the uplink from the source cell to the target cell comprises storing a transmission power and a timing parameter corresponding to the uplink, and the returning the transmission of the uplink from the target cell to the source cell comprises utilizing the stored transmission power and timing parameter for the transmission of the uplink.

15. An apparatus for wireless communication in a cellular network comprising a source cell and a target cell, the apparatus comprising:

means for switching transmission of an uplink from the source cell to the target cell while maintaining a downlink with the source cell;

means for determining to return the transmission of the uplink to the source cell; and

means for switching the transmission of the uplink from the target cell to the source cell.

16. The apparatus of claim 15, wherein the means for determining to return the transmission of the uplink to the source cell comprises means for determining a failure of the uplink to the target cell.

17. The apparatus of claim 16, wherein the means for determining the failure of the uplink to the target cell comprises means for determining, at an expiration of a timer corresponding to the switching the transmission of the uplink from the source cell to the target cell, that the uplink to the target was not acquired.

18. The apparatus of claim 16, wherein the means for determining the failure of the uplink to the target cell comprises means for determining that an error rate of the uplink is higher than a threshold error rate.

19. The apparatus of claim 15, wherein the means for determining to return the transmission of the uplink to the source cell comprises means for determining that at least one of a signal strength or a SINR of the downlink has increased, or that an error rate of the downlink has decreased.

20. The apparatus of claim 15, further comprising:

means for switching reception of a downlink from the source cell to the target cell;

means for determining to return the reception of the downlink to the source cell; and

means for returning the reception of the downlink from the target cell to the source cell.

21. The apparatus of claim 20, wherein the means for determining to return the reception of the downlink to the source cell comprises means for determining a failure of the downlink from the target cell.

22. The apparatus of claim 21, wherein the means for determining the failure of the downlink from the target cell comprises means for determining that at least one of a signal strength or a SINR of the downlink is lower than a threshold, or that an error rate is higher than an error threshold.

23. The apparatus of claim 21, wherein the means for determining the failure of the downlink from the target cell comprises means for determining, at an expiration of a timer corresponding to the switching the transmission of the downlink from the source cell to the target cell, that the downlink from the target cell was not acquired.

24. The apparatus of claim 20, wherein, when a location of a user equipment utilizing the uplink and the downlink, or a metric of quality of the downlink, are substantially the same since a time when the switching the transmission of the uplink began, the means for returning the reception of the downlink from the target cell to the source cell comprises means for first returning the transmission of the uplink from the target cell to the source cell, and subsequently returning the reception of the downlink from the target cell to the source cell.

25. The apparatus of claim 24, wherein the metric of quality of the downlink comprises a received signal strength corresponding to the downlink and a delay in the downlink.

26. The apparatus of claim 20, wherein, when a location of a user equipment utilizing the uplink and the downlink, and a metric of quality of the downlink, have changed by an amount greater than respective predetermined thresholds, the means for returning the reception of the downlink from the target cell to the source cell comprises means for returning the transmission of the uplink and the reception of the downlink from the target cell to the source cell at substantially the same time.

27. The apparatus of claim 26, wherein the metric of quality of the downlink comprises a received signal strength corresponding to the downlink and a delay in the downlink.

28. The apparatus of claim 15, wherein the means for switching the transmission of the uplink from the source cell to the target cell comprises means for storing a transmission power and a timing parameter corresponding to the uplink, and the means for returning the transmission of the uplink from the target cell to the source cell comprises means for utilizing the stored transmission power and timing parameter for the transmission of the uplink.

29. A computer program product, comprising:

a computer-readable medium comprising;

code for switching transmission of an uplink from the source cell to the target cell while maintaining a downlink with the source cell;

code for determining to return the transmission of the uplink to the source cell; and

code for switching the transmission of the uplink from the target cell to the source cell.

30. The computer program product of claim 29, wherein the code for determining to return the transmission of the uplink to the source cell comprises code for determining a failure of the uplink to the target cell.

31. The computer program product of claim 30, wherein the code for determining the failure of the uplink to the target cell comprises code for determining, at an expiration of a timer corresponding to the switching the transmission of the uplink from the source cell to the target cell, that the uplink to the target was not acquired.

32. The computer program product of claim 30, wherein the code for determining the failure of the uplink to the target cell comprises code for determining that an error rate of the uplink is higher than a threshold error rate.

33. The computer program product of claim 29, wherein the code for determining to return the transmission of the uplink to the source cell comprises code for determining that at least one of a signal strength or a SINR of the downlink has increased, or that an error rate of the downlink has decreased.

34. The computer program product of claim 29, further comprising:

code for switching reception of a downlink from the source cell to the target cell;

code for determining to return the reception of the downlink to the source cell; and

code for returning the reception of the downlink from the target cell to the source cell.

35. The computer program product of claim 34 wherein the code for determining to return the reception of the downlink to the source cell comprises code for determining a failure of the downlink from the target cell.

36. The computer program product of claim 35, wherein the code for determining the failure of the downlink from the target cell comprises code for determining that at least one of a signal strength or a SINR of the downlink is lower than a threshold, or that an error rate is higher than an error threshold.

37. The computer program product of claim 35, wherein the code for determining the failure of the downlink from the target cell comprises code for determining, at an expiration of a timer corresponding to the switching the transmission of the downlink from the source cell to the target cell, that the downlink from the target cell was not acquired.

38. The computer program product of claim 34, wherein, when a location of a user equipment utilizing the uplink and the downlink, or a metric of quality of the downlink, are substantially the same since a time when the switching the transmission of the uplink began, the code for returning the reception of the downlink from the target cell to the source cell comprises code for first returning the transmission of the uplink from the target cell to the source cell, and subsequently returning the reception of the downlink from the target cell to the source cell.

39. The computer program product of claim 38, wherein the metric of quality of the downlink comprises a received signal strength corresponding to the downlink and a delay in the downlink.

40. The computer program product of claim 34, wherein, when a location of a user equipment utilizing the uplink and the downlink, and a metric of quality of the downlink, have changed by an amount greater than respective predetermined thresholds, the code for returning the reception of the downlink from the target cell to the source cell comprises code for returning the transmission of the uplink and the reception of the downlink from the target cell to the source cell at substantially the same time.

41. The computer program product of claim 40, wherein the metric of quality of the downlink comprises a received signal strength corresponding to the downlink and a delay in the downlink.

42. The computer program product of claim 29 wherein the code for switching the transmission of the uplink from the source cell to the target cell comprises code for storing a transmission power and a timing parameter corresponding to the uplink, and the code for returning the transmission of the uplink from the target cell to the source cell comprises code for utilizing the stored transmission power and timing parameter for the transmission of the uplink.

43. An apparatus for wireless communication in a cellular network comprising a source cell and a target cell, the apparatus comprising:

at least one processor; and

a memory coupled to the at least one processor,

wherein the at least one processor is configured to;

switch transmission of an uplink from the source cell to the target cell while maintaining a downlink with the source cell;

determine to return the transmission of the uplink to the source cell; and

return the transmission of the uplink from the target cell to the source cell.

44. The apparatus of claim 43, wherein the determining to return the transmission of the uplink to the source cell comprises determining a failure of the uplink to the target cell.

45. The apparatus of claim 44, wherein the determining the failure of the uplink to the target cell comprises determining, at an expiration of a timer corresponding to the switching the transmission of the uplink from the source cell to the target cell, that the uplink to the target call was not acquired.

46. The apparatus of claim 44 wherein the determining the failure of the uplink to the target cell comprises determining that an error rate of the uplink is higher than a threshold error rate.

47. The apparatus of claim 43, wherein the determining to return the transmission of the uplink to the source cell comprises determining that at least one of a signal strength or a SINR of the downlink has increased, or that an error rate of the downlink has decreased.

48. The apparatus of claim 43, wherein the at least one processor is further configured to:

switch reception of a downlink from the source cell to the target cell;

determine to return the reception of the downlink to the source cell; and

return the reception of the downlink from the target cell to the source cell.

49. The apparatus of claim 48, wherein the determining to return the reception of the downlink to the source cell comprises determining a failure of the downlink from the target cell.

50. The apparatus of claim 49, wherein the determining the failure of the downlink from the target cell comprises determining that at least one of a signal strength or a SINR of the downlink is lower than a threshold, or that an error rate is higher than an error threshold.

51. The apparatus of claim 49, wherein the determining the failure of the downlink from the target cell comprises determining, at an expiration of a timer corresponding to the switching the transmission of the downlink from the source cell to the target cell, that the downlink from the target cell was not acquired.

52. The apparatus of claim 48, wherein, when a location of a user equipment utilizing the uplink and the downlink, or a metric of quality of the downlink, are substantially the same since a time when the switching the transmission of the uplink began, the returning the reception of the downlink from the target cell to the source cell comprises first returning the transmission of the uplink from the target cell to the source cell, and subsequently returning the reception of the downlink from the target cell to the source cell.

53. The apparatus of claim 52, wherein the metric of quality of the downlink comprises a received signal strength corresponding to the downlink and a delay in the downlink.

54. The apparatus of claim 48, wherein, when a location of a user equipment utilizing the uplink and the downlink, and a metric of quality of the downlink, have changed by an amount greater than respective predetermined thresholds, the returning the reception of the downlink from the target cell to the source cell comprises returning the transmission of the uplink and the reception of the downlink from the target cell to the source cell at substantially the same time.

55. The apparatus of claim 54, wherein the metric of quality of the downlink comprises a received signal strength corresponding to the downlink and a delay in the downlink.

56. The apparatus of claim 43, wherein the switching the transmission of the uplink from the source cell to the target cell comprises storing a transmission power and a timing parameter corresponding to the uplink, and the returning the transmission of the uplink from the target cell to the source cell comprises utilizing the stored transmission power and timing parameter for the transmission of the uplink.