Handover reliability enhancement in wireless communication

Patent metadata

Field	Value
Publication number	US-11963052-B2
Application number	US-202117450550-A
Country	US
Kind code	B2
Filing date	Oct 11, 2021
Priority date	Oct 16, 2020
Publication date	Apr 16, 2024
Grant date	Apr 16, 2024

Abstract

A method for user equipment (UE) service handover from the serving cell to a target cell includes information regarding a handover timer and an associated handover execution condition. For scheduled handover to be performed upon expiration of the handover timer, the associated handover execution condition comprises one or more abort conditions for aborting the scheduled handover. For two-stage triggered handover to be performed upon receipt of a subsequent triggering message, the handover timer is a handover validity timer and the associated handover execution condition comprises receipt of the handover triggering message prior to expiration of the handover validity timer.

First claim

What is claimed is:

1. A serving cell, comprising:
a processor configured to generate a radio resource control (RRC) reconfiguration message including information indicating handover execution conditions and handover cancelation conditions for conditional handover (CHO) of service for a user equipment (UE) from the serving cell to a target cell, wherein:
a first of the handover execution conditions is based on whether a distance between the UE and a reference location is less than a threshold value,
a second of the handover execution conditions is based on whether a time elapsed from when the UE received the RRC reconfiguration message is greater than a threshold value, and
a first of the handover cancelation conditions is based on whether a distance between the UE and the reference location is greater than a threshold value; and

a transceiver operably coupled to the processor, the transceiver configured to:
transmit, to the UE, the RRC reconfiguration message, and
receive a handover completion acknowledgement based on completion of the CHO from the serving cell to the target cell.

2. The serving cell of claim 1 , wherein a second of the handover cancelation conditions is based on whether a time elapsed from when the UE received the RRC reconfiguration message is greater than a threshold value.

3. The serving cell of claim 1 , wherein:
the RRC reconfiguration message further includes information indicating a handover timer associated with a third of the handover execution conditions,
in case the handover timer is a scheduled handover timer for a scheduled handover to be performed for the UE upon expiration of the scheduled handover timer, the third handover execution condition comprises one or more abort conditions for aborting the scheduled handover, and
in case the handover timer is a handover validity timer for a predicted handover to be performed based on receipt at the UE of a handover triggering message, the third handover execution condition comprises receipt of the handover triggering message prior to expiration of the handover validity timer.

4. The serving cell of claim 3 , wherein, in case the handover timer is a handover validity timer:
the third handover execution condition further comprises the one or more abort conditions for aborting the predicted handover, and
the handover triggering message includes an index of the handover timer among one or more configured handover timers.

5. The serving cell of claim 3 , wherein the serving cell configures the handover validity timer based on one or more of a location of the UE, a location of a transmission reception point (TRP), a trajectory of the UE, or a trajectory of the TRP.

6. The serving cell of claim 3 , wherein:
in case the handover timer is a handover validity timer, the transceiver is further configured to transmit a group triggering message to one or multiple UEs, and
wherein the group triggering message is scrambled with radio network temporary identifier (RNTI) known for a group of UEs and the group triggering message includes one or more of UE identifications triggered for handover among the UEs in the group of UEs.

7. The serving cell of claim 3 , wherein the one or more abort conditions comprise at least one of:
a radio resource management (RRM) event, and
a location of the UE.

8. The serving cell of claim 7 , wherein the RRM event comprises at least one of:
a measurement for the serving cell being better than a first threshold value upon expiration of the scheduled handover timer,
a measurement for a third cell being better, upon expiration of the scheduled handover timer, than one or more of the measurement for the serving cell, a measurement for the target cell, or a second threshold value, and
the measurement for the target cell being less than a third threshold value upon expiration of the scheduled handover timer.

9. The serving cell of claim 7 , wherein the location of the UE comprises a location-based abort condition comprising a measurement of UE location deviation from a location at which the UE was activated with the handover timer.

10. A user equipment (UE), comprising:
a transceiver configured to receive a radio resource control (RRC) reconfiguration message including information indicating handover execution conditions and handover cancelation conditions for conditional handover (CHO) of service for a user equipment (UE) from a serving cell to a target cell, wherein:
a first of the handover execution conditions is based on whether a distance between the UE and a reference location is less than a threshold value,
a second of the handover execution conditions is based on whether a time elapsed from when the UE received the RRC reconfiguration message is greater than a threshold value, and
a first of the handover cancelation conditions is based on whether a distance between the UE and the reference location is greater than a threshold value; and

a processor operably coupled to the transceiver, the processor configured to determine whether to initiate the CHO based on the handover execution conditions and the handover cancelation conditions,
wherein the transceiver is configured to transmit a handover completion acknowledgement based on completion of the CHO from the serving cell to the target cell.

11. The UE of claim 10 , wherein a second of the handover cancelation conditions is based on whether a time elapsed from when the UE received the RRC reconfiguration message is greater than a threshold value.

12. The UE of claim 10 , wherein:
the RRC reconfiguration message further includes information indicating a handover timer associated with a third of the handover execution conditions,
in case the handover timer is a scheduled handover timer for a scheduled handover to be performed for the UE upon expiration of the scheduled handover timer, the third handover execution condition comprises one or more abort conditions for aborting the scheduled handover, and
in case the handover timer is a handover validity timer for a predicted handover to be performed based on receipt at the UE of a handover triggering message, the third handover execution condition comprises receipt of the handover triggering message prior to expiration of the handover validity timer.

13. The UE of claim 12 , wherein the one or more abort conditions comprise at least one of:
a radio resource management (RRM) event, and
a location of the UE.

14. The UE of claim 13 , wherein the RRM event comprises at least one of:
a measurement for the serving cell being better than a first threshold value upon expiration of the scheduled handover timer,
a measurement for a third cell being better, upon expiration of the scheduled handover timer, than one or more of the measurement for the serving cell, a measurement for the target cell, or a second threshold value, and
the measurement for the target cell being less than a third threshold value upon expiration of the scheduled handover timer.

15. The UE of claim 13 , wherein the location of the UE comprises a location-based abort condition comprising a measurement of UE location deviation from a location at which the UE was activated with the handover timer.

16. A method for operating a user equipment (UE), the method comprising:
receiving a radio resource control (RRC) reconfiguration message including information indicating handover execution conditions and handover cancelation conditions for conditional handover (CHO) of service for a user equipment (UE) from a serving cell to a target cell, wherein:
a first of the handover execution conditions is based on whethe

Assignees

• Samsung Electronics Co Ltd

Inventors

• Jeon Jeongho
• Jeong Kyeongin
• Cho Joonyoung
• Park Andrew
• Kim Eunsun

Classifications

• H04W36/362 Primary

  Conditional handover · CPC title

• H04W36/322

  by location data · CPC title

• H04W36/249

  according to timing information · CPC title

• H04W36/00837 Primary

  Determination of triggering parameters for hand-off · CPC title

• H04W36/0072

  of resource information of target access point · CPC title