Mobility parameter adjustment and mobility state estimation in heterogeneous networks
View Patent ↗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.
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, 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;
determining, by the UE, one or more mobility parameters based on the cell change type, wherein the one or more mobility parameters include a timer-to-trigger parameter, the time-to-trigger parameter determined by applying a scaling factor associated with the cell change type to a nominal time-to-trigger value, the scaling factor associated with the cell change type is based, at least in part, on the transmission power level of the neighboring cell and the transmission power level of the UE's serving cell; 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 one of a macro-pico handover, a pico-macro handover, a pico-pico handover, and a macro-macro handover.
5. The method of claim 1 , further comprising receiving, by the UE, the time-to-trigger parameter from a base station, using a radio resource control (RRC) message.
6. The method of claim 1 , 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.
7. The method of claim 1 , wherein the transmission power of the neighboring cell is signaled to the serving cell via a backhaul interface.
8. The method of claim 1 , wherein the one or more mobility parameters include a measurement report event trigger threshold.
9. The method of claim 8 , 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.
10. The method of claim 9 , 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.
11. The method of claim 9 , wherein the offset associated with the cell change type and UE speed is pre-configured.
12. The method of claim 1 , wherein the one or more mobility parameters include a timer associated with cell range expansion.
13. 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.
14. 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.
15. The method of claim 14 , wherein the number of cell changes is scaled based on associated cell change types.
16. The method of claim 1 , wherein the mobility procedure is a cell reselection procedure.
17. The method of claim 16 , wherein the cell reselection procedure includes a procedure for the UE to change its serving cell in an idle mode.
18. The method of claim 16 , wherein the one or more mobility parameters include a cell reselection timer.
19. The method of claim 16 , wherein the one or more mobility parameters include a cell reselection threshold.
20. The method of claim 16 , wherein the one or more mobility parameters are scaled based on the UE mobility state, cell range expansion value and cell change type.
21. The method of claim 16 , further comprising receiving the one or more mobility parameters from a base station, using a system information block (SIB) message.
22. 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, 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;
determine one or more mobility parameters based on the cell change type, wherein the one or more mobility parameters include a timer-to-trigger parameter, the time-to-trigger parameter determined by applying a scaling factor associated with the cell change type to a nominal time-to-trigger value, the scaling factor associated with the cell change type is based, at least in part, on the transmission power level of the neighboring cell and the transmission power level of the UE's serving cell; and
execute a mobility procedure with the neighboring cell using the one or more mobility parameters.
23. The user equipment of claim 22 , wherein the mobility procedure comprises a cell handover procedure.
24. The user equipment of claim 23 , wherein the cell handover procedure includes a procedure for the UE to change its serving cell in a connected mode.
25. The user equipment of claim 23 , 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.
26. The user equipment of claim 22 , 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.
27. The user equipment of claim 22 , 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.
28. The user equipment of claim 22 , wherein the transmission power of the neighboring cell is signaled to the serving cell via a backhaul interface.
29. The user equipment of claim 22 , wherein the one or more mobility parameters include a measurement report event trigger threshold.
30. The user equipment of claim 29 , 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.
31. The user equipment of claim 30 , 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.
32. The user equipment of claim 30 , wherein the offset associated with the cell change type and UE speed is pre-configured.
33. The user equipment of claim 22 , wherein the one or more mobility parameters include a timer associated with cell range expansion.
34. The user equipment of claim 22 , 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.
35. The user equipment of claim 22 , 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.
36. The user equipment of claim 35 , wherein the number of cell changes is scaled based on associated cell change types.
37. The user equipment of claim 22 , wherein the mobility procedure is a cell reselection procedure.
38. The user equipment of claim 37 , wherein the cell reselection procedure includes a procedure for the UE to change its serving cell in an idle mode.
39. The user equipment of claim 37 , wherein the one or more mobility parameters include a cell reselection timer.
40. The user equipment of claim 37 , wherein the one or more mobility parameters include a cell reselection threshold.
41. The user equipment of claim 37 , wherein the one or more mobility parameters are scaled based on the UE mobility state, cell range expansion value and cell change type.
42. The user equipment of claim 37 , 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.
43. A non-transitory computer-readable medium coupled to the one or more processors having instructions stored thereon which, when executed by the one or more processors, cause the one or more processors to perform operations comprising:
identifying a cell change type associated with a neighboring cell, wherein the cell change type is based, at least in part, on a transmission power level of a user equipment's (UE) serving cell and a transmission power level of the neighboring cell;
determining one or more mobility parameters based on the cell change type, wherein the one or more mobility parameters include a timer-to-trigger parameter, the time-to-trigger parameter determined by applying a scaling factor associated with the cell change type to a nominal time-to-trigger value, the scaling factor associated with the cell change type is based, at least in part, on the transmission power level of the neighboring cell and the transmission power level of the UE's serving cell; and
executing a mobility procedure with the neighboring cell using the one or more mobility parameters.
44. The non-transitory computer-readable medium of claim 43 , wherein the mobility procedure comprises a cell handover procedure.
45. The non-transitory computer-readable medium of claim 44 , wherein the cell handover procedure includes a procedure for the UE to change its serving cell in a connected mode.
46. The non-transitory computer-readable medium of claim 43 , 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.
47. The non-transitory computer-readable medium of claim 43 , the operations further comprising receiving, by the UE, the time-to-trigger parameter from a base station, using a radio resource control (RRC) message.
48. The non-transitory computer-readable medium of claim 43 , the operations 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.
49. The non-transitory computer-readable medium of claim 43 , wherein the transmission power of the neighboring cell is signaled to the serving cell via a backhaul interface.
50. The non-transitory computer-readable medium of claim 43 , wherein the one or more mobility parameters include a measurement report event trigger threshold.
51. The non-transitory computer-readable medium of claim 50 , 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.
52. The non-transitory computer-readable medium of claim 51 , the operations 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.
53. The non-transitory computer-readable medium of claim 50 , wherein the offset associated with the cell change type and UE speed is pre-configured.
54. The non-transitory computer-readable medium of claim 43 , wherein the one or more mobility parameters include a timer associated with cell range expansion.
55. The non-transitory computer-readable medium of claim 43 , the operations further comprising estimating by the UE its speed and reporting the speed or a quantized representation of its speed to a base station.
56. The non-transitory computer-readable medium of claim 43 , 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.
57. The non-transitory computer-readable medium of claim 56 , wherein the number of cell changes is scaled based on associated cell change types.
58. The non-transitory computer-readable medium of claim 43 , wherein the mobility procedure is a cell reselection procedure.
59. The non-transitory computer-readable medium of claim 58 , wherein the cell reselection procedure includes a procedure for the UE to change its serving cell in an idle mode.
60. The non-transitory computer-readable medium of claim 43 , wherein the one or more mobility parameters include a cell reselection timer or a cell reselection threshold.
61. The non-transitory computer-readable medium of claim 43 , wherein the one or more mobility parameters are scaled based on the UE mobility state, cell range expansion value and cell change type.
62. The non-transitory computer-readable medium of claim 43 , the operations further comprising receiving the one or more mobility parameters from a base station, using a system information block (SIB) message.