Search

EP-4740521-A1 - ROAMING SERVICE FOR A CLIENT DEVICE IN CASE OF A FAILURE CONDITION

EP4740521A1EP 4740521 A1EP4740521 A1EP 4740521A1EP-4740521-A1

Abstract

Embodiments of the invention relate to a client device (100) and a network access node (300) for providing roaming service to the client device (100) in case of a failure condition such as a disaster condition. Upon a failure condition in a first core network (600) of a first PLMN serving the client device (100), the network access node (300) can notify the client device (100) using a first release message (502) indicating the failure condition in the first core network (600). Based on the first release message (502), the client device (100) can move to an idle state and may select a second PLMN for providing roaming service to the client device (100). Alternatively, the network access node (300) can select a second PLMN for providing roaming service to the client device (100) and notify the client device (100) using a reconfiguration message (510) indicating the selected second PLMN and the failure condition in the first core network (600) of the first PLMN. Furthermore, embodiments of the invention also relate to a network node (720), corresponding methods and a computer program.

Inventors

  • MOPIDEVI, RAMA KUMAR
  • PREMAN, Vishnu
  • LI, BINGZHAO
  • QIANG, LI
  • Zhang, Tingrui

Assignees

  • Huawei Technologies Co., Ltd.

Dates

Publication Date
20260513
Application Date
20230719

Claims (20)

  1. A client device (100) for a communication system (500) , the client device (100) being configured to: receive a first release message (502) from a network access node (300) , the first release message (502) indicating a disaster condition in a first core network (600) of a first public land mobile network, PLMN, serving the client device (100) .
  2. The client device (100) according to claim 1, configured to: receive the first release message (502) when being in a connected state with the network access node (300) and/or having an active packet data unit, PDU, session with the first core network (600) .
  3. The client device (100) according to claim 1 or 2, configured to: move to an idle state upon receiving the first release message (502) .
  4. The client device (100) according to any one of the preceding claims, wherein the first release message (502) further indicates a set of second PLMNs configured to provide a disaster roaming service for the first PLMN and/or a system information block 15, SIB15, associated with the set of second PLMNs.
  5. The client device (100) according to claim 4, wherein the set of second PLMNs are a set of forbidden PLMNs for the client device (100) .
  6. The client device (100) according to claim 4 or 5, wherein the first release message (502) further comprises an indication to request a SIB15, and the client device (100) is configured to: transmit a system information request message (504) to the network access node (300) , the system information request message (504) indicating a request for a SIB15; and receive the SIB15 from the network access node (300) in response to the system information request message (504) .
  7. The client device (100) according to any one of claims 4 to 6, configured to: select a second PLMN from the set of second PLMNs for providing the disaster roaming service for the first PLMN based on the first release message (502) .
  8. The client device (100) according to claim 7, configured to: transmit a PDU session request message (506) to the network access node (300) , the PDU session request message (506) indicating a request for a PDU session with a second core network (700) of the selected second PLMN.
  9. The client device (100) according to claim 8, configured to: receive a second release message (502′) from the network access node (300) when having an active PDU session with the second core network (700) of the selected second PLMN, the second release message (502′) indicating a disaster over condition in the first core network (600) of the first PLMN.
  10. The client device (100) according to any one of the preceding claims, wherein the first release message (502) and/or second release message (502′) is a radio resource control, RRC, release message.
  11. A network access node (300) for a communication system (500) , the network access node (300) being configured to: transmit a first release message (502) to a client device (100) , the first release message (502) indicating a disaster condition in a first core network (600) of a first PLMN serving the client device (100) .
  12. The network access node (300) according to claim 11, wherein the first release message (502) further indicates a set of second PLMNs configured to provide a disaster roaming service for the first PLMN and/or a SIB15 associated with the set of second PLMNs.
  13. The network access node (300) according to claim 11 or 12, wherein the first release message (502) further comprises an indication to request a SIB15, and the network access node (300) is configured to receive a system information request message (504) from the client device (100) , the system information request message (504) indicating a request for a SIB15; and transmit the SIB15 to the client device (100) in response to the system information request message (504) .
  14. The network access node (300) according to any one of claims 11 to 13, configured to: receive a PDU session request message (506) from the client device (100) , the PDU session request message (506) indicating a request for a PDU session with a second core network (700) of a second PLMN.
  15. The network access node (300) according to 14, configured to: transmit a second release message (502′) to the client device (100) when the client device (100) has an active PDU session with the second core network (700) of the second PLMN, the second release message (502′) indicating a disaster over condition in the first core network (600) of the first PLMN.
  16. The network access node (300) according to any one of claims 11 to 15, wherein the first release message (502) and/or second release message (502′) is a RRC release message.
  17. The network access node (300) according to any one of claims 11 to 16, wherein the network access node (300) belongs to a shared radio access network, RAN, the shared RAN being shared by the first core network (600) of the first PLMN and a set of second core networks (700a, 700b, …700n) of a set of second PLMNs.
  18. A method (200) for a client device (100) , the method (200) comprises: receiving (202) a first release message (502) from a network access node (300) , the first release message (502) indicating a disaster condition in a first core network (600) of a first public land mobile network, PLMN, serving the client device (100) .
  19. A method (400) for a network access node (300) , the method (400) comprises: transmitting (402) a first release message (502) to a client device (100) , the first release message (502) indicating a disaster condition in a first core network (600) of a first PLMN serving the client device (100) .
  20. A computer program with a program code for performing a method according to claim 18 or 19 when the computer program runs on a computer.

Description

ROAMING SERVICE FOR A CLIENT DEVICE IN CASE OF A FAILURE CONDITION Technical Field Embodiments of the invention relate to a client device and a network access node for providing roaming service to the client device in case of a failure condition such as a disaster condition. Furthermore, embodiments of the invention also relate to a network node, corresponding methods and a computer program. Background Functionality was implemented in 3GPP release 17 specifications to provide service for a user equipment (UE) when the mobile network of the UE fails to provide service due to a disaster such as e.g., a fire or flooding. The functionality enables a UE of a given public land mobile network (PLMN) to obtain connectivity service such as e.g., voice or data from another PLMN when the UE has a disaster roaming agreement with that PLMN. This feature is called minimization of service interruption (MINT) . In short, the MINT feature enables a UE of a first PLMN in a disaster condition to select and register on a second PLMN from a forbidden PLMN list for the UE. In this way, the UE can obtain service in a disaster condition even when no other PLMNs except PLMNs in the forbidden PLMN list of the UE are available. The MINT feature in 3GPP release 17 handles the scenario where a radio access network (RAN) of a PLMN is in a disaster condition and the core network of the PLMN is functional. The disaster condition is notified to other PLMN (s) by the PLMN itself, an operations, administration and maintenance (OAM) system or government agencies. How the other PLMNs are notified about the disaster is out of 3GPP scope. The other PLMN (s) can then broadcast information to enable UEs to obtain a disaster roaming service. Summary An objective of embodiments of the invention is to provide a solution which mitigates or solves the drawbacks and problems of conventional solutions. Another objective of embodiments of the invention is to provide a solution which enables a client device to obtain roaming service in case of a failure condition in a core network serving the client device. The above and further objectives are solved by the subject matter of the independent claims. Further embodiments of the invention can be found in the dependent claims. According to a first aspect of the invention, the above mentioned and other objectives are achieved with a client device for a communication system, the client device being configured to: receive a first release message from a network access node, the first release message indicating a disaster condition in a first core network of a first public land mobile network, PLMN, serving the client device. An advantage of the client device according to the first aspect is that the client device can be informed about the disaster condition in the first core network directly with the release message. The client device will thereby not attempt to reconnect to the first PLMN after the release. The client device can instead take steps to obtain service from another PLMN (s) if the client device subscription allows disaster roaming. In this way, network resources can be saved and the power consumption in the client device can be reduced. In an implementation form of a client device according to the first aspect, the client device is configured to: receive the first release message when being in a connected state with the network access node and/or having an active packet data unit, PDU, session with the first core network. An advantage with this implementation form is that the network access node can use the first release message to release the connection with the client device and inform the client device about the reason for the release. Attempts to reconnect to the unavailable first PLMN can thereby be avoided. In an implementation form of a client device according to the first aspect, the client device is configured to: move to an idle state upon receiving the first release message. An advantage with this implementation form is that the first release message can trigger the client device to release the connection with the network access node and inform the client device about the reason for the release. Attempts to reconnect to the unavailable first PLMN can thereby be avoided. In an implementation form of a client device according to the first aspect, the first release message further indicates a set of second PLMNs configured to provide a disaster roaming  service for the first PLMN and/or a system information block 15, SIB15, associated with the set of second PLMNs. An advantage with this implementation form is that the client device can obtain the set of second PLMNs and/or the SIB15 directly from the first release message and does not have to wait for broadcasted system information. This reduces the power consumption in the client device as the client device does not have to perform system information decoding to obtain the set of second PLMNs and/or the SIB15. In an implementation fo