Granted Patent B2

US 12,501,327 · App. 18/305,838 · Granted Dec 16, 2025

Inventor: Minsung Cho (Suwon-si, KR)

Assignee: Samsung Electronics Co., Ltd.

H04W36/00835H04W36/0085H04W36/30H04W72/56H04W76/19

Abstract

Claims (75)

1 . A method performed by a radio access network (RAN) controller connected to base stations, the method comprising:

obtaining measurement reports of a plurality of user equipments (UEs), each measurement report of the measurement reports comprising a measurement result per cell of a corresponding UE;

identifying candidate cells of a UE among the plurality of UEs, based on the measurement reports, wherein the candidate cells comprise a first cell for access and a second cell for access to be performed in response to a failure of the access to the first cell; and

transmitting, to a serving base station for the UE, a control message comprising identification information for indicating the UE and identification information for indicating the candidate cells of the UE,

wherein the control message indicates a handover priority of each cell of the candidate cells.

2 . The method of claim 1 , wherein the handover is performed after the connection failure to the first cell while maintaining a radio resource control (RRC) connection state.

3 . The method of claim 1 ,

wherein the access to the second cell is initiated before an expiry of a timer for a radio resource control (RRC) re-establishment, and

wherein the timer is started by a RRC reconfiguration message for indicating a handover to the first cell.

4 . The method of claim 1 , wherein the obtaining of the measurement reports comprises:

receiving, from each base station, a report message comprising a UE identifier (ID) indicating a specific UE and a measurement report corresponding to the UE ID,

wherein the measurement report comprises a cell ID for indicating a specific cell, and a measurement result for the specific cell, and

wherein the measurement result for the specific cell comprises at least one of:

a reference signal received power (RSRP),

a reference signal received quality (RSRQ), or

a signal-to-noise ratio (SINR).

5 . The method of claim 1 , further comprising:

transmitting, to the serving base station, configuration information regarding a pre-detection condition of call drop,

wherein the configuration information is used to configure the serving base station to perform a handover to a target cell of a measurement report of the UE, in case that the pre-detection condition is satisfied.

6 . The method of claim 1 , wherein the control message indicates that at least one cell among the candidate cells of the UE is used for a dual-active protocol stack (DAPS) handover.

7 . The method of claim 1 ,

wherein the measurement reports of the plurality of UEs are obtained from report messages received during a designated interval, and

wherein the designated interval is configured to be smaller than a length of a T304 timer related to a handover failure.

8 . A radio access network (RAN) controller connected to base stations, the RAN controller comprising:

at least one transceiver; and

at least one processor operably coupled to the at least one transceiver and configured to:

obtain measurement reports of a plurality of user equipments (UEs), each measurement report of the measurement reports comprising a measurement result per cell of a corresponding UE,

identify candidate cells of a UE among the plurality of UEs, based on the measurement reports, wherein the candidate cells comprise a first cell for access and a second cell for access to be performed in response to a failure of the access to the first cell, and

transmit, to a serving base station for the UE, a control message comprising identification information for indicating the UE and identification information for indicating the candidate cells of the UE,

wherein the control message indicates a handover priority of each cell of the candidate cells.

9 . The RAN controller of claim 8 , wherein the handover is performed after the connection failure to the first cell while maintaining a radio resource control (RRC) connection state.

10 . The RAN controller of claim 8 ,

wherein the access to the second cell is initiated before an expiry of a timer for a radio resource control (RRC) re-establishment, and

wherein a T304 timer is started by a RRC reconfiguration message for indicating a handover to the first cell.

11 . The RAN controller of claim 8 , wherein the at least one processor is, to obtain the measurement reports, configured to:

receive, from each base station, a report message comprising a UE identifier (ID) indicating a specific UE and a measurement report corresponding to the UE ID,

wherein the measurement report comprises a cell ID for indicating a specific cell, and a measurement result for the specific cell, and

wherein the measurement result for the specific cell comprises at least one of:

a reference signal received power (RSRP),

a reference signal received quality (RSRQ), or

a signal-to-noise ratio (SINR).

12 . The RAN controller of claim 8 ,

wherein the at least one processor is further configured to transmit, to the serving base station, configuration information regarding a pre-detection condition of call drop, and

wherein the configuration information is used to configure the serving base station to perform a handover to a target cell of a measurement report of the UE, in case that the pre-detection condition is satisfied.

13 . The RAN controller of claim 8 , wherein the control message indicates that at least one cell among the candidate cells of the UE is used for a dual-active protocol stack (DAPS) handover.

14 . The RAN controller of claim 8 ,

wherein the measurement reports of the plurality of UEs are obtained from report messages received during a designated interval, and

wherein the designated interval is configured to be smaller than a length of a T304 timer related to a handover failure.

15 . A device of a base station, the device comprising:

at least one transceiver; and

at least one processor operably coupled to the at least one transceiver and configured to:

receive at least one measurement report from at least one user equipment (UE), each measurement report of the at least one measurement report comprising a measurement result per cell of a corresponding UE,

transmit, to a radio access network (RAN) controller, a report message comprising the at least one measurement report,

receive, from the RAN controller, a control message comprising identification information for indicating a UE and identification information for indicating candidate cells of the UE, and

transmit, to the UE, a handover command,

wherein the control message indicates a handover priority of each cell of the candidate cells, and

wherein the candidate cells comprise a first cell for access and a second cell for access to be performed in response to a failure of the first access to the first cell.

16 . The device of claim 15 , wherein the handover is performed after the connection failure to the first cell while maintaining a radio resource control (RRC) connection state.

17 . The device of claim 15 ,

wherein the handover is initiated before an expiry of a timer for a radio resource control (RRC) re-establishment, and

wherein a T304 timer is started by a RRC reconfiguration message for indicating a handover to the first cell.

18 . The device of claim 15 ,

wherein the report message comprises a UE identifier (ID) indicating a specific UE and a measurement report corresponding to the UE ID,

wherein the measurement report comprises a cell ID for indicating a specific cell and a measurement result for the specific cell, and

wherein the measurement result for the specific cell comprises at least one of:

a reference signal received power (RSRP),

a reference signal received quality (RSRQ), or

a signal-to-noise ratio (SINR).

19 . The device of claim 15 ,

wherein the handover command comprises information on the first cell and information on the second cell.

20 . The device of claim 15 ,

wherein the at least one processor is further configured to:

receive, from the RAN controller, configuration information regarding a pre-detection condition of call drop; and

in case that the pre-detection condition is satisfied, transmit, to the UE, a radio resource control (RRC) reconfiguration message for indicating a handover to a target cell, and

wherein the target cell is indicated based on a measurement report of the UE.

Assignments (1)

Priority Claims (1)

Continuity (2)

References Cited (28)