Method and cell for determining handover of PDU session

• US 10,708,830 B2
• Filed: 06/05/2018
• Issued: 07/07/2020
• Est. Priority Date: 06/06/2017
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Youn, Myungjune, Kim, Hyunsook, Ryu, Jinsook
• Primary Examiner(s): Perez-Gutierrez, Rafael
• Assistant Examiner(s): Donado, Frank E
• Application Number:
  US16/613,107
• Publication Number:
  US 20200100147A1
• Time in Patent Office: 763 Days
• Field of Search: 455436
• CPC Class Codes: H04W 36/0033 with transfer of context information
• CPC Class Codes: H04W 36/0055 Transmission or use of information for re-establishing the radio link
• CPC Class Codes: H04W 36/0058 Transmission of hand-off measurement information, e.g. measurement reports
• CPC Class Codes: H04W 36/00835 Determination of neighbour cell lists
• CPC Class Codes: H04W 36/04 Reselecting a cell layer in multi-layered cells
• CPC Class Codes: H04W 36/14 Reselecting a network or an air interface

Abstract

A disclosed feature of the present specification provides a method for a source cell determining a handover of a packet data unit (PDU) session. The method may include a step of determining a target cell or target next generation radio access network (NG-RAN) based on a measurement report by a terminal. A handover region list can additionally be considered in the target cell or target NG-RAN determination step. The method may include a step of transmitting a handover request message that does not include context with respect to the PDU session to the target cell or target NG-RAN, based on the handover region list, if it is confirmed that the determined target cell or target NG-RAN cannot serve for the PDU session.

Claims

1. A method for determining a handover of a Packet Data Unit (PDU) session, the method performed by a source cell and comprising:

determining, by the source cell, a target cell or a target Next Generation Radio Access Network (NG-RAN) based on a measurement report of a user equipment (UE), wherein a handover region list is additionally considered in determining the target cell or the target NG-RAN; and

transmitting, by the source cell, a handover request message that does not include context with respect to the PDU session to the target cell or the target NG-RAN, based on the handover region list and the determined target cell or target NG-RAN, when the determined target cell or target NG-RAN is unable to service the PDU session, in response to the PDU session not taking place within a region in which the PDU session is to be serviced,

wherein the determining the target cell or target NG-RAN includes;

confirming a handover region list with respect to each of a plurality of PDU sessions, based on presence of a plurality of handover region lists; and

selecting a target cell or a target NG-RAN to which a plurality of PDU sessions are all handed over, based on the plurality of handover region lists.

2. The method of claim 1, wherein the PDU session is used for a Local Area Data Network (LADN).

3. The method of claim 1, wherein the handover request message is transmitted for a handover procedure using Xn interface.

4. The method of claim 1, wherein the handover region list is configured for each PDU session.

5. The method of claim 1, wherein the handover region list includes information about a region in which handover is limited or allowed with respect to the corresponding PDU session.

6. The method of claim 5, further comprising obtaining the handover region list from an Access and Mobility Management Function (AMF) or Session Management Function (SMF) node during a PDU session establishment procedure.

7. The method of claim 1, further comprising deleting context with respect to the PDU session, based on the handover region list, in response to confirming that the determined target cell or target NG-RAN is unable to service the PDU session.

8. The method of claim 1, wherein the plurality of handover region lists is confirmed in order of priority.

9. The method of claim 8, wherein, in the absence of a target cell or a target NG-RAN to which the plurality of PDU sessions is all handed over, a handover region list with a low priority is excluded from use.

10. A cell that determines handover of a Packet Data Unit (PDU) session, the cell comprising:

a transceiver; and

a processor determining a target cell or a target NG-RAN based on a measurement report of a user equipment (UE), wherein a handover region list is additionally considered in determining the target cell or the target NG-RAN,

wherein the processor transmits a handover request message that does not include context with respect to the PDU session to the target cell or the target NG-RAN, based on the handover region list and the determined target cell or target NG-RAN, when the determined target cell or target NG-RAN is unable to service the PDU session, in response to the PDU session not taking place within a region in which the PDU session is to be serviced, and

wherein the determining the target cell or target NG-RAN includes;

confirming a handover region list with respect to each of a plurality of PDU sessions, based on presence of a plurality of handover region lists; and

selecting a target cell or a target NG-RAN to which a plurality of PDU sessions are all handed over, based on the plurality of handover region lists.