METHOD AND APPARATUS FOR PERFORMING HANDOVER IN MOBILE COMMUNICATION SYSTEM

• US 20200137638A1
• Filed: 10/25/2019
• Published: 04/30/2020
• Est. Priority Date: 10/26/2018
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: KIM, Donggun
• Granted Patent: US 11,284,309 B2
• Time in Patent Office: Days
• CPC Class Codes: H04W 36/0011 for data sessions of end-to-end connection
• CPC Class Codes: H04W 36/0038 of security context information
• CPC Class Codes: H04W 36/0055 Transmission or use of information for re-establishing the radio link
• CPC Class Codes: H04W 36/06 Reselecting a communication resource in the serving access point

Abstract

A method of performing communication, by a user equipment (UE), in a wireless communication system, the method including receiving a radio resource control (RRC) message including a handover command, identifying whether a security key is updated based on the RRC message, and performing a packet data convergence protocol (PDCP) process based on a bearer type and a result of the identification.

Claims

1. A method of performing communication, by a user equipment (UE), in a wireless communication system, the method comprising:

receiving a radio resource control (RRC) message including a handover command;

identifying whether a security key is updated based on the RRC message; and

performing a packet data convergence protocol (PDCP) process based on a bearer type and a result of the identification.

2. The method of claim 1, wherein the performing of the PDCP process comprises performing, based on the security key not updated, a PDCP re-establishment process for a signaling radio bearer (SRB) and an unacknowledged mode data radio bearer (UM DRB) and a PDCP data recovery for an acknowledged mode data radio bearer (AM DRB).

3. The method of claim 1, wherein the performing of the PDCP process comprises performing, based on the security key not updated, a PDCP data recovery for an acknowledged mode data radio bearer (AM DRB),

wherein no PDCP procedure is triggered for a signaling radio bearer (SRB) and an unacknowledged mode data radio bearer (UM DRB) based on the update of the security key.

4. The method of claim 1, wherein the performing of the PDCP process comprises performing, based on an updated security key, a PDCP re-establishment process for a signaling radio bearer (SRB), an unacknowledged mode data radio bearer (UM DRB) and an acknowledged mode data radio bearer (AM DRB).

5. The method of claim 1, wherein the security key is not updated based on a handover within a distributed unit (DU) or between DUs connected to a same central unit (CU).

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

determining an update of a security key based on a type of a handover determined based on a measurement report;

determining a packet data convergence protocol (PDCP) process for each of bearers based on the update of the security key and a bearer type; and

transmitting a radio resource control (RRC) message for triggering the handover and the determined PDCP process for each of the bearers.

7. The method of claim 6, wherein the determining of the PDCP process comprises, based on the security key not updated, determining a PDCP re-establishment process for a signaling radio bearer (SRB) and an unacknowledged mode data radio bearer (UM DRB) and a PDCP data recovery for an acknowledged mode data radio bearer (AM DRB).

8. The method of claim 6, wherein the determining of the PDCP process comprises, based on the security key not updated, determining a PDCP data recovery for an acknowledged mode data radio bearer (AM DRB),

wherein no PDCP procedure is triggered for a signaling radio bearer (SRB) and an unacknowledged mode data radio bearer (UM DRB) based on the update of the security key.

9. The method of claim 6, wherein the determining of the PDCP process comprises determining, based on an updated security key, a PDCP re-establishment process for a signaling radio bearer (SRB), an unacknowledged mode data radio bearer (UM DRB) and an acknowledged mode data radio bearer (AM DRB).

10. The method of claim 6, wherein the security key is not updated based on a handover within a distributed unit (DU) or between DUs connected to a same central unit (CU).

11. A user equipment (UE) of performing communication in a wireless communication system, the UE comprising:

a transceiver; and

a processor coupled with the transceiver and configured to;

control the transceiver to receive a radio resource control (RRC) message including a handover command,

identify whether a security key is updated based on the RRC message, and

perform a packet data convergence protocol (PDCP) process based on a bearer type and a result of the identification.

12. The UE of claim 11, wherein the processor is configured to, based on the security key not updated, perform a PDCP re-establishment process for a signaling radio bearer (SRB) and an unacknowledged mode data radio bearer (UM DRB) and a PDCP data recovery for an acknowledged mode data radio bearer (AM DRB).

13. The UE of claim 11, wherein the processor is configured to, based on the security key not updated, perform a PDCP data recovery for an acknowledged mode data radio bearer (AM DRB),

wherein no PDCP procedure is triggered for a signaling radio bearer (SRB) and an unacknowledged mode data radio bearer (UM DRB) based on the update of the security key.

14. The UE of claim 11, wherein the processor is configured to perform, based on an updated security key, a PDCP re-establishment process for a signaling radio bearer (SRB), an unacknowledged mode data radio bearer (UM DRB) and an acknowledged mode data radio bearer (AM DRB).

15. The UE of claim 11, wherein the security key is not updated based on a handover within a distributed unit (DU) or between DUs connected to a same central unit (CU).

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

a transceiver; and

a processor coupled with the transceiver and configured to;

determine an update of a security key based on a type of a handover determined based on a measurement report,

determine a packet data convergence protocol (PDCP) process for each of bearers based on the update of the security key and a bearer type, and

control the transceiver to transmit a radio resource control (RRC) message for triggering the handover and the determined PDCP process for each of the bearers.

17. The base station of claim 16, wherein the processor is configured to, based on the security key not updated, determine, a PDCP re-establishment process for a signaling radio bearer (SRB) and an unacknowledged mode data radio bearer (UM DRB) and a PDCP data recovery for an acknowledged mode data radio bearer (AM DRB).

18. The base station of claim 16, wherein the processor is configured to, based on the security key not updated, determine a PDCP data recovery for an acknowledged mode data radio bearer (AM DRB),

wherein no PDCP procedure is triggered for a signaling radio bearer (SRB) and an unacknowledged mode data radio bearer (UM DRB) based on the update of the security key.

19. The base station of claim 16, wherein the processor is configured to, based on an updated security key, determine a PDCP re-establishment process for a signaling radio bearer (SRB), an unacknowledged mode data radio bearer (UM DRB) and an acknowledged mode data radio bearer (AM DRB).

20. The base station of claim 16, wherein the security key is not updated based on a handover within a distributed unit (DU) or between DUs connected to a same central unit (CU).