Granted Patent B2

US 12,581,368 · App. 18/449,639 · Granted Mar 17, 2026

Inventors: Jaehyuk Jang (Suwon-si, KR); Soenghun Kim (Suwon-si, KR); Sangbum Kim (Suwon-si, KR); Donggun Kim (Seoul, KR); Seungri Jin (Suwon-si, KR)

Assignee: Samsung Electronics Co., Ltd.

H04W28/26H04W28/0268H04W28/0278H04W36/249H04W72/1215H04W72/1268H04W72/569H04W28/0215H04W36/0064H04W72/0453

Abstract

Claims (81)

1 . A method performed by a terminal in a wireless communication system, the method comprising:

receiving, from a source base station, a first message comprising conditional handover configuration information, the conditional handover configuration information comprising information on at least one candidate target cell, information on at least one execution condition for a conditional handover of the at least one candidate target cell, and information on a T304 timer;

identifying a target cell in case that the at least one execution condition for the target cell among the at least one candidate target cell is fulfilled;

starting the T304 timer, in case that the at least one execution condition is fulfilled; and

transmitting, to a target base station to which the target cell belongs, a second message for completion of the conditional handover to the target cell.

2 . The method of claim 1 ,

wherein the at least one candidate target cell belongs to at least one candidate target base station.

3 . The method of claim 1 , further comprising:

stopping the T304 timer based on a successful completion of the conditional handover.

4 . The method of claim 1 ,

wherein the first message includes a radio resource control (RRC) reconfiguration message, and

wherein the at least one execution condition comprises at least one of at least one measurement result of the at least one candidate target cell becomes a predetermined offset better than a measurement result of a primary cell, or the measurement result of the primary cell becomes worse than a first threshold and the at least one measurement result of the at least one candidate target cell becomes better than a second threshold.

5 . The method of claim 1 , further comprising:

receiving, from the source base station, a third message including measurement configuration information for a measurement; and

transmitting, to the source base station, a fourth message including measurement result based on the measurement configuration information,

wherein the measurement configuration information comprises information on at least one measurement object and information on at least one measurement report configuration, and

wherein the third message includes a radio resource control (RRC) reconfiguration message.

6 . A method performed by a source base station in a wireless communication system, the method comprising:

transmitting, to a terminal, a first message comprising conditional handover configuration information, the conditional handover configuration information comprising information on at least one candidate target cell, information on at least one execution condition for a conditional handover of the at least one candidate target cell, and information on a T304 timer;

receiving, from a target base station to which a target cell belongs, a second message indicating that the terminal has successfully accessed the target cell; and

releasing resources associated to a terminal context,

wherein the T304 timer is started on the terminal, in case that the at least one execution condition for the target cell among the at least one candidate target cell is fulfilled.

7 . The method of claim 6 ,

wherein the first message includes a radio resource control (RRC) reconfiguration message, and

wherein the at least one execution condition comprises at least one of at least one measurement result of the at least one candidate target cell becomes a predetermined offset better than a measurement result of a primary cell, or the measurement result of the primary cell becomes worse than a first threshold and the at least one measurement result of the at least one candidate target cell becomes better than a second threshold.

8 . The method of claim 6 ,

wherein the at least one candidate target cell belongs to at least one candidate target base station.

9 . The method of claim 6 , wherein the transmitting the first message further comprises:

transmitting, to the terminal, a third message including measurement configuration information for a measurement;

receiving, from the terminal, a fourth message including measurement result based on the measurement configuration information;

determining whether to use the conditional handover based on the measurement result;

transmitting, to at least one candidate target base station, a fifth message for requesting the conditional handover of the terminal;

receiving, from the at least one candidate target base station, a sixth message as a response to the fifth message; and

transmitting, to the terminal, the first message comprising the conditional handover configuration information,

wherein the at least one candidate target cell belongs to the at least one candidate target base station,

wherein the measurement configuration information comprises information on at least one measurement object and information on at least one measurement report configuration, and

wherein the third message includes a radio resource control (RRC) reconfiguration message.

10 . The method of claim 6 ,

wherein the T304 timer is a stopped based on a successful completion of the conditional handover.

11 . A terminal in a wireless communication system, the terminal comprising:

a transceiver; and

a controller configured to:

receive, from a source base station via the transceiver, a first message comprising conditional handover configuration information, the conditional handover configuration information comprising information on at least one candidate target cell, information on at least one execution condition for a conditional handover of the at least one candidate target cell, and information on a T304 timer,

identify a target cell in case that the at least one execution condition for the target cell among the at least one candidate target cell is fulfilled,

start the T304 timer, in case that the at least one execution condition is fulfilled, and

transmit, to a target base station to which the target cell belongs via the transceiver, a second message for completion of the conditional handover to the target cell.

12 . The terminal of claim 11 ,

wherein the at least one candidate target cell belongs to at least one candidate target base station.

13 . The terminal of claim 11 , wherein the controller is further configured to:

stop the T304 timer based on a successful completion of the conditional handover.

14 . The terminal of claim 11 ,

wherein the first message includes a radio resource control (RRC) reconfiguration message, and

wherein the at least one execution condition comprises at least one of at least one measurement result of the at least one candidate target cell becomes a predetermined offset better than a measurement result of a primary cell, or the measurement result of the primary cell becomes worse than a first threshold and the at least one measurement result of the at least one candidate target cell becomes better than a second threshold.

15 . The terminal of claim 11 , wherein the controller is further configured to:

receive, from the source base station via the transceiver, a third message including measurement configuration information for a measurement, and

transmit, to the source base station via the transceiver, a fourth message including measurement result based on the measurement configuration information,

wherein the measurement configuration information comprises information on at least one measurement object and information on at least one measurement report configuration, and

wherein the third message includes a radio resource control (RRC) reconfiguration message.

16 . A source base station in a wireless communication system, the source base station comprising:

a transceiver; and

a controller configured to:

transmit, to a terminal via the transceiver, a first message comprising conditional handover configuration information, the conditional handover configuration information comprising information on at least one candidate target cell, information on at least one execution condition for a conditional handover of the at least one candidate target cell, and information on a T304 timer,

receive, from a target base station to which a target cell belongs via the transceiver, a second message indicating that the terminal has successfully accessed the target cell, and

release resources associated to a terminal context,

wherein the T304 timer is started on the terminal, in case that the at least one execution condition for the target cell among the at least one candidate target cell is fulfilled.

17 . The source base station of claim 16 ,

wherein the first message includes a radio resource control (RRC) reconfiguration message, and

wherein the at least one execution condition comprises at least one of at least one measurement result of the at least one candidate target cell becomes a predetermined offset better than a measurement result of a primary cell, or the measurement result of the primary cell becomes worse than a first threshold and the at least one measurement result of the at least one candidate target cell becomes better than a second threshold.

18 . The source base station of claim 16 , wherein the at least one candidate target cell belongs to at least one candidate target base station.

19 . The source base station of claim 16 , wherein the controller is further configured to:

transmit, to the terminal via the transceiver, a third message including measurement configuration information for a measurement,

receive, from the terminal via the transceiver, a fourth message including measurement result based on the measurement configuration information,

determine whether to use the conditional handover based on the measurement result,

transmit, to at least one candidate target base station via the transceiver, a fifth message for requesting the conditional handover of the terminal,

receive, from the at least one candidate target base station via the transceiver, a sixth message as a response to the fifth message, and

transmit, to the terminal via the transceiver, the first message comprising the conditional handover configuration information,

wherein the at least one candidate target cell belongs to the at least one candidate target base station,

wherein the measurement configuration information comprises information on at least one measurement object and information on at least one measurement report configuration, and

wherein the third message includes a radio resource control (RRC) reconfiguration message.

20 . The source base station of claim 16 ,

wherein the T304 timer is a stopped based on a successful completion of the conditional handover.

Assignments (1)

Priority Claims (1)

Continuity (3)

References Cited (60)