MOBILITY PARAMETER ADJUSTMENT AND MOBILITY STATE ESTIMATION IN HETEROGENEOUS NETWORKS

• US 20130244664A1
• Filed: 03/16/2012
• Published: 09/19/2013
• Est. Priority Date: 03/16/2012
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Blackberry Limited
• Inventors: Song, Yi, Bontu, Chandra Sekhar, Cai, Zhijun
• Granted Patent: US 8,744,449 B2
• Time in Patent Office: Days
• US Class Current: 455/437
• CPC Class Codes: H04W 36/00835 Determination of neighbour cell lists
• CPC Class Codes: H04W 36/00837 Determination of triggering parameters for hand-off
• CPC Class Codes: H04W 36/0085 Hand-off measurements
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/32 by location or mobility data, e.g. speed data
• CPC Class Codes: H04W 84/045 using private Base Stations, e.g. femto Base Stations, home Node B
• CPC Class Codes: H04W 84/047 using dedicated repeater stations

Abstract

Systems and methods for mobility parameter adjustment and mobility state estimation in heterogeneous networks are provided. The mobility parameters may be adjusted based on the cell change types associated with the mobility procedure. The mobility procedure may be a cell handover procedure or a cell reselection procedure. The cell change type may be dependent on the transmission power level of the UE'"'"'s serving cell and neighboring cells. In some implementations, the UE may provide a speed information to the serving cell such that the serving eNB may prioritize or optimize the mobility procedure for the UE. The UE may also estimate its mobility state by counting the number of cell changes within certain period of time and applying scaling factors to the number of cell changes based on the associated cell change types.

Claims

1. A method of operating user equipment (UE) in a wireless communications network, the method comprising:

identifying, by the UE, a cell change type associated with a neighboring cell;

determining, by the UE, one or more mobility parameters based on the cell change type; and

executing, by the UE, a mobility procedure with the neighboring cell using the one or more mobility parameters.

2. The method of claim 1, wherein the mobility procedure comprises a cell handover procedure.

3. The method of claim 2, wherein the cell handover procedure includes a procedure for the UE to change its serving cell in a connected mode.

4. The method of claim 1, wherein the cell change type is based, at least in part, on a transmission power level of the UE'"'"'s serving cell and a transmission power level of the neighboring cell.

5. The method of claim 1, wherein the cell change type is one of a macro-pico handover, a pico-macro handover, a pico-pico handover, and a macro-macro handover.

6. The method of claim 1, wherein the one or more mobility parameters include a timer-to-trigger parameter.

7. The method of claim 6, further comprising receiving, by the UE, the time-to-trigger parameter from a base station, using a radio resource control (RRC) message.

8. The method of claim 6, wherein the time-to-trigger parameter is determined by applying a scaling factor associated with the cell change type to a nominal time-to-trigger value.

9. The method of claim 8, further comprising receiving, by the UE, the scaling factor associated with the cell change type from a base station, using a radio resource control (RRC) message.

10. The method of claim 8, wherein the scaling factor associated with the cell change type is based, at least in part, on a transmission power level of the neighboring cell and a transmission power level of the UE'"'"'s serving cell.

11. The method of claim 10, wherein the transmission power of the neighboring cell is signaled to the serving cell via a backhaul interface.

12. The method of claim 1, wherein the one or more mobility parameters include a measurement report event trigger threshold.

13. The method of claim 12, wherein the measurement report event trigger threshold is adjusted by applying an offset associated with the cell change type and UE speed to a nominal measurement report event trigger threshold.

14. The method of claim 13, further comprising receiving, by the UE, the offset associated with the cell change type and UE speed from a base station, using a RRC message.

15. The method of claim 13, wherein the offset associated with the cell change type and UE speed is pre-configured.

16. The method of claim 1, wherein the one or more mobility parameters include a timer associated with cell range expansion.

17. The method of claim 1, further comprising estimating by the UE its speed and reporting the speed or a quantized representation of its speed to a base station.

18. The method of claim 1, further comprising determining, by the UE, a mobility state associated with the UE based on a number of cell changes during a certain period of time.

19. The method of claim 18, wherein the number of cell changes is scaled based on associated cell change types.

20. The method of claim 1, wherein the mobility procedure is a cell reselection procedure.

21. The method of claim 20, wherein the cell reselection procedure includes a procedure for the UE to change its serving cell in an idle mode.

22. The method of claim 20, wherein the one or more mobility parameters include a cell reselection timer.

23. The method of claim 20, wherein the one or more mobility parameters include a cell reselection threshold.

24. The method of claim 20, wherein the one or more mobility parameters are scaled based on the UE mobility state, cell range expansion value and cell change type.

25. The method of claim 20, further comprising receiving the one or more mobility parameters from a base station, using a system information block (SIB) message.

26. User equipment (UE) for operating in a wireless communications network, comprising one or more processors configured to:

identify a cell change type associated with a neighboring cell;

determine one or more mobility parameters based on the cell change type; and

execute a mobility procedure with the neighboring cell using the one or more mobility parameters.

27. The user equipment of claim 26, wherein the mobility procedure comprises a cell handover procedure.

28. The user equipment of claim 27, wherein the cell handover procedure includes a procedure for the UE to change its serving cell in a connected mode.

29. The user equipment of claim 27, wherein the cell change type is one of a macro-pico handover, a pico-macro handover, a pico-pico handover, and a macro-macro handover.

30. The user equipment of claim 26, wherein the cell change type is based, at least in part, on a transmission power level of the UE'"'"'s serving cell and a transmission power level of the neighboring cell.

31. The user equipment of claim 26, wherein the one or more mobility parameters include a timer-to-trigger parameter.

32. The user equipment of claim 31, the one or more processors further configured to receive the time-to-trigger parameter from a base station, using a radio resource control (RRC) message.

33. The user equipment of claim 31, wherein the time-to-trigger parameter is determined by applying a scaling factor associated with the cell change type to a nominal time-to-trigger value.

34. The user equipment of claim 33, the one or more processors further configured to receive the scaling factor associated with the cell change type from a base station, using a radio resource control (RRC) message.

35. The user equipment of claim 33, wherein the scaling factor associated with the cell change type is based, at least in part, on a transmission power level of the neighboring cell and a transmission power level of the UE'"'"'s serving cell.

36. The user equipment of claim 35, wherein the transmission power of the neighboring cell is signaled to the serving cell via a backhaul interface.

37. The user equipment of claim 26, wherein the one or more mobility parameters include a measurement report event trigger threshold.

38. The user equipment of claim 37, wherein the measurement report event trigger threshold is adjusted by applying an offset associated with the cell change type and UE speed to a nominal measurement report event trigger threshold.

39. The user equipment of claim 38, the one or more processors further configured to receive the offset associated with the cell change type and UE speed from a base station, using a RRC message.

40. The user equipment of claim 38, wherein the offset associated with the cell change type and UE speed is pre-configured.

41. The user equipment of claim 26, wherein the one or more mobility parameters include a timer associated with cell range expansion.

42. The user equipment of claim 26, the one or more processors further configured to estimate its speed and report the speed or a quantized representation of its speed to a base station.

43. The user equipment of claim 26, the one or more processors further configured to determine a mobility state associated with the UE based on a number of cell changes during a certain period of time.

44. The user equipment of claim 43, wherein the number of cell changes is scaled based on associated cell change types.

45. The user equipment of claim 26, wherein the mobility procedure is a cell reselection procedure.

46. The user equipment of claim 45, wherein the cell reselection procedure includes a procedure for the UE to change its serving cell in an idle mode.

47. The user equipment of claim 45, wherein the one or more mobility parameters include a cell reselection timer.

48. The user equipment of claim 45, wherein the one or more mobility parameters include a cell reselection threshold.

49. The user equipment of claim 45, wherein the one or more mobility parameters are scaled based on the UE mobility state, cell range expansion value and cell change type.

50. The user equipment of claim 45, the one or more processors further configured to receive the one or more mobility parameters from a base station, using a system information block (SIB) message.

51. A base station device for communication with user equipment (UE) in a wireless communications network, the base station device comprising one or more processors configured to:

signal transmission power level information of the base station device to the UE for identifying a cell chance type;

determine one or more mobility parameters associated with the cell change type; and

signal the one or more mobility parameters to the UE.

52. The base station device of claim 51, wherein the cell change type is based, at least in part, on a transmission power level of the UE'"'"'s serving cell and a transmission power level of a UE'"'"'s neighboring cell.

53. The base station device of claim 51, wherein the one or more mobility parameters include a timer-to-trigger parameter.

54. The base station device of claim 53, wherein the base station device is configured to signal the time-to-trigger parameter to the UE using a radio resource control (RRC) message.

55. The base station device of claim 53, wherein the base station device is configured to signal the time-to-trigger parameter to the UE by signaling a scaling factor associated with the cell change type relative to a nominal time-to-trigger value.

56. The base station device of claim 55, wherein the base station device is configured to signal the scaling factor associated with the cell change type to the UE using a radio resource control (RRC) message.

57. The base station device of claim 55, wherein the scaling factor associated with the cell change type is based, at least in part, on a transmission power of the base station device and a transmission power of a neighboring cell.

58. The base station device of claim 57, wherein the transmission power of the neighboring cell is signaled to the base station device via a backhaul interface.

59. The base station device of claim 51, wherein the one or more mobility parameters include a measurement report event trigger threshold.

60. The base station device of claim 59, wherein the base station device is configured to signal the measurement report event trigger threshold to the UE by signaling an offset associated with the cell change type and UE speed relative to a nominal measurement report event trigger threshold.

61. The base station device of claim 60, wherein the base station device is configured to signal the offset associated with the cell change type and UE speed to the UE using a RRC message.

62. The base station device of claim 60, wherein the offset associated with the cell change type and UE speed is pre-configured.

63. The base station device of claim 51, wherein the one or more mobility parameters include a timer associated with cell range expansion.

64. The base station device of claim 51, the one or more processors further configured to receive a UE speed estimation from the UE.

65. The base station device of claim 64, the one or more processors are further configured to:

determine that the UE is in a high mobility state; and

transmit a handover command to the UE prior to receiving a handover request acknowledgment message from a target cell.

66. The base station device of claim 51, wherein the one or more mobility parameters include a cell reselection timer.

67. The base station device of claim 51, wherein the one or more mobility parameters include a cell reselection threshold.

68. The base station device of claim 51, wherein the base station device is configured to signal the one or more mobility parameters to the UE using a system information block (SIB) message.