Method and apparatus for secondary cell release during handover in a wireless communication system
Methods and an apparatus for Secondary Cell (SCell) release during User Equipment (UE) handover comprises including information by a source eNB in a HandoverPreparationInformation message for a target eNB to control SCell release in the UE during handover, or including an indicator by a target eNB in a handover command for the UE to distinguish whether or not to release all configured SCells.
1. A method of Secondary Cell (SCell) release during handover comprising:
configuring at least one SCell by a source eNB to a User Equipment (UE); and
including information by the source eNB in a HandoverPreparationInformation message for a target eNB to control SCell release in the UE during a handover,
wherein the information indicates SCell indexes of all SCells configured to the UE before the handover, thereby allowing the target eNB to include a sCellToReleaseList with all the SCells configured to the UE in a handover command for the UE to release the SCells included in the sCellToReleaseList.
2. The method of claim 1 , wherein the handover command corresponds to an RRCConnectionReconfiguration message including mobilityControlInfo.
3. The method of claim 2 , wherein the RRCConnectionReconfiguration message is sent from the source eNB to the UE to initiate a handover procedure.
4. The method of claim 2 , wherein the HandoverPreparationInformation message is sent from the source eNB to the target eNB to request the handover.
5. The method of claim 2 , wherein the handover is an inter-eNB handover.
6. The method of claim 3 , wherein the HandoverPreparationInformation message is sent from the source eNB to the target eNB to request the handover.
7. The method of claim 3 , wherein the handover is an inter-eNB handover.
8. The method of claim 1 , wherein the HandoverPreparationInformation message is sent from the source eNB to the target eNB to request the handover.
9. The method of claim 8 , wherein the handover is an inter-eNB handover.
10. The method of claim 1 , wherein the handover is an inter-eNB handover.
11. The method of claim 1 , wherein a RRCConnectionReconfiguration message is sent from the source eNB to the UE to initiate a handover procedure.
12. A communication device for use in a wireless communication system, the communication device comprising:
a control circuit;
a processor installed in the control circuit; and
a memory installed in the control circuit and coupled to the processor;
wherein the processor is configured to execute a program code stored in memory to:
configuring at least one SCell by a source eNB to a User Equipment (UE); and
including information by the source eNB in a HandoverPreparationInformation message for a target eNB to control SCell release in the UE during a handover,
wherein the information indicates SCell indexes of all SCells configured to the UE before the handover, thereby allowing the target eNB to include a sCellToReleaseList with all the SCells configured to the UE in a handover command for the UE to release the SCells included in the sCellToReleaseList.
13. The device of claim 12 , wherein the handover command corresponds to an RRCConnectionReconfiguration message including mobilityControlInfo.
14. The device of claim 13 , wherein the RRCConnectionReconfiguration message is sent from the source eNB to the UE to initiate a handover procedure.
15. The device of claim 13 , wherein the HandoverPreparationInformation message is sent from the source eNB to the target eNB to request the handover.
16. The device of claim 13 , wherein the handover is an inter-eNB handover.
17. The device of claim 14 , wherein the HandoverPreparationInformation message is sent from the source eNB to the target eNB to request the handover.
18. The device of claim 14 , wherein the handover is an inter-eNB handover.
19. The device of claim 12 , wherein the HandoverPreparationInformation message is sent from the source eNB to the target eNB to request the handover.
20. The device of claim 19 , wherein the handover is an inter-eNB handover.
21. The device of claim 12 , wherein the handover is an inter-eNB handover.
22. The device of claim 12 , wherein a RRCConnectionReconfiguration message is sent from the source eNB to the UE to initiate a handover procedure.