Method, apparatus and computer program

Abstract

The invention relates to a method, an apparatus and a computer program. There is provided an apparatus comprising: means for receiving, at a target public land mobile network, signaling for establishing a protocol data unit session for a first service for a user equipment, where the first service can be hosted by the target public land mobile network and a home public land mobile network; and means for causing data associated with the protocol data unit session for the first service to be transmitted between the target public land mobile network and a visited public land mobile network with which the user equipment is registered.

Description

Technical Field

[0001] Various example embodiments of the present disclosure are directed to methods, apparatus, and computer programs for wireless communication systems. Background Art

[0002] A communication system may be a facility for enabling communication sessions between two or more entities such as user terminals, base stations / access points, and / or other nodes by providing carriers between the various entities involved in the communication path. For example, a communication system may be provided by a communication network and one or more compatible communication devices. For example, a communication session may include data communications for carrying communications such as voice, electronic mail (email), text messaging, multimedia, and / or content data, etc. Non-limiting examples of the services provided include two-way or multi-way calls, data communications or multimedia services, and access to data network systems such as the Internet. Summary of the invention

[0003] Details describing aspects of various example embodiments follow.

[0004] According to one aspect, a device is provided, comprising: a device for receiving, at a target public land mobile network, signaling for establishing a protocol data unit session for a first service for a user equipment, wherein the first service can be hosted by the target public land mobile network and a home public land mobile network; and a device for causing data associated with the protocol data unit session for the first service to be transmitted between the target public land mobile network and a visited public land mobile network, wherein the user equipment is registered with the visited public land mobile network.

[0005] In some aspects, means for receiving includes means for receiving a network function discovery request from the home public land mobile network.

[0006] In some aspects, the apparatus includes means for providing information about a session management function of the target public land mobile network to the visited public land mobile network for use in establishing the protocol data unit session.

[0007] In some aspects, the information about the session management function of the target public land mobile network is provided in an Nnrf_NFDiscovery_Request response message.

[0008] In some aspects, the device for receiving includes: a device for receiving a service request message from a session management function of the home public land mobile network at a session management function of the target public land mobile network, the service request message including at least one of the following: information related to the protocol data unit session establishment request, or subscription data related to the user equipment.

[0009] In some aspects, the apparatus for receiving includes: means for receiving, at the session management function of the target public land mobile network, a protocol data unit session establishment request message from a session management function of the home public land mobile network; and wherein the apparatus includes: means for selecting a user plane function of the target public land mobile network to service the protocol data unit session; and means for responding to the session management function of the home public land mobile network with an indication of the selected user plane function of the target public land mobile network.

[0010] In some aspects, means for receiving, at a target public land mobile network, signaling for establishing a protocol data unit session for a first service for a user equipment includes means for receiving the signaling for establishing a protocol data unit session for a first service for a user equipment from the visited public land mobile network.

[0011] In some aspects, the device includes: a device for obtaining session management subscription data from a unified data management function of the home public land mobile network, the session management subscription data including at least one of the following according to the data network name: an indication of whether the data network name supports roaming value-added service routing to a target public land mobile network, or an identifier of the target public land mobile network.

[0012] According to one aspect, an apparatus is provided, comprising: a circuit configured to execute, at a target public land mobile network, receiving signaling for establishing a protocol data unit session for a first service for a user equipment, wherein the first service can be hosted by the target public land mobile network and a home public land mobile network; and a circuit configured to execute so that data associated with the protocol data unit session for the first service is transmitted between the target public land mobile network and a visited public land mobile network, wherein the user equipment is registered with the visited public land mobile network.

[0013] According to one aspect, a device is provided, comprising: a device for determining whether to route signaling for establishing a protocol data unit session for a first service for a user equipment to a target public land mobile network based on at least one of the following: a data network name associated with the first service, subscription data associated with the user equipment, or an identifier of a visited public land mobile network serving the user equipment, wherein the user equipment is registered with the visited public land mobile network, wherein the first service can be hosted by the target public land mobile network and a home public land mobile network; and a device for routing the signaling for establishing the protocol data unit session at the target public land mobile network based on the determination.

[0014] In some aspects, the apparatus for routing signaling for establishing the protocol data unit session includes: an apparatus for forwarding a network function discovery request from the visited public land mobile network to the target public land mobile network based on at least one of: a data network name associated with the first service, subscription data associated with the user equipment, or an identifier of a visited public land mobile network serving the user equipment.

[0015] In some aspects, the apparatus includes means for using, at a network repository function of the home public land mobile network, a stored configuration including an indication of a serving public land mobile network and a data network name mapped to a target public land mobile network.

[0016] In some aspects, the device includes: a device for receiving a protocol data unit session establishment request for the user equipment from the visited public land mobile network at a session management function of the home public land mobile network; and a device for providing a service request message to the session management function of the target public land mobile network based on the protocol data unit session establishment request, wherein the service request message includes at least one of the following: information associated with the protocol data unit session establishment request, or subscription data associated with the user equipment.

[0017] In some aspects, the apparatus includes means for controlling, by a session management function of the home public land mobile network, a user plane function of the target public land mobile network by encapsulating an N4 message in a service request message from the session management function of the home public land mobile network to a session management function of the target public land mobile network.

[0018] In some aspects, the apparatus includes: an apparatus for storing session management subscription data for the user equipment at a unified data management function of the home public land mobile network, the session management subscription data including at least one of the following: a data network name having an indication of supporting roaming value-added service routing, or a target public land mobile network identifier having an indication of supporting roaming value-added service routing.

[0019] In some aspects, the apparatus includes: an apparatus for storing session management function selection subscription data at a unified data management function of the home public land mobile network, the session management function selection subscription data including at least one of the following according to the data network name: an indication of whether the data network name supports roaming value-added service routing to a target public land mobile network, or an identifier of the target public land mobile network; and an apparatus for providing the session management function selection subscription data for the user equipment to the target land mobile network based on a request received from the session management function of the target public land mobile network.

[0020] According to one aspect, an apparatus is provided, comprising: a circuit configured to perform a determination of whether to route signaling for establishing a protocol data unit session for a first service for a user equipment to a target public land mobile network based on at least one of: a data network name associated with the first service, subscription data associated with the user equipment, or an identifier of a visited public land mobile network serving the user equipment, wherein the user equipment is registered with the visited public land mobile network, wherein the first service can be hosted by the target public land mobile network and a home public land mobile network; and a circuit configured to perform, based on the determination, routing signaling for establishing the protocol data unit session at the target public land mobile network.

[0021] According to one aspect, a device is provided, comprising: at least one processor, and at least one memory, wherein the at least one memory stores instructions, which, when executed by the at least one processor, cause the device to perform: receiving, at a target public land mobile network, signaling for establishing a protocol data unit session for a first service for a user equipment, wherein the first service can be hosted by the target public land mobile network and a home public land mobile network; and causing data associated with the protocol data unit session for the first service to be transmitted between the target public land mobile network and a visited public land mobile network, wherein the user equipment registers with the visited public land mobile network.

[0022] In some aspects, the receiving includes receiving a network function discovery request from the home public land mobile network.

[0023] In some aspects, the apparatus is caused to perform: providing information about a session management function of the target public land mobile network to the visited public land mobile network for use in establishing the protocol data unit session.

[0024] In some aspects, information about the session management function of the target public land mobile network is provided in an Nnrf_NFDiscovery_Request response message.

[0025] In some aspects, the receiving includes: receiving a service request message from a session management function of the home public land mobile network at a session management function of the target public land mobile network, the service request message including at least one of: information associated with the protocol data unit session establishment request, or subscription data associated with the user equipment.

[0026] In some aspects, the receiving comprises: receiving, at the session management function of the target public land mobile network, a protocol data unit session establishment request message from a session management function of the home public land mobile network; and wherein the method comprises: selecting a user plane function of the target public land mobile network to serve the protocol data unit session; and responding to the session management function of the home public land mobile network with an indication of the selected user plane function of the target public land mobile network.

[0027] In some aspects, receiving, at the target public land mobile network, signaling to establish a protocol data unit session for the first service for the user equipment includes receiving the signaling to establish a protocol data unit session for the first service for the user equipment from the visited public land mobile network.

[0028] In some aspects, the device is caused to execute: obtaining session management subscription data from a unified data management function of the home public land mobile network, the session management subscription data including at least one of the following according to the data network name: an indication of whether the data network name supports roaming value-added service routing to a target public land mobile network, or an identifier of the target public land mobile network.

[0029] According to one aspect, a method is provided, comprising: receiving, at a target public land mobile network, signaling for establishing a protocol data unit session for a first service for a user equipment, wherein the first service can be hosted by the target public land mobile network and a home public land mobile network; and causing data associated with the protocol data unit session for the first service to be transmitted between the target public land mobile network and a visited public land mobile network, wherein the user equipment is registered with the visited public land mobile network.

[0030] In some aspects, the receiving includes receiving a network function discovery request from the home public land mobile network.

[0031] In some aspects, the method includes providing information about a session management function of the target public land mobile network to the visited public land mobile network for use in establishing the protocol data unit session.

[0032] In some aspects, the information about the session management function of the target public land mobile network is provided in an Nnrf_NFDiscovery_Request response message.

[0033] In some aspects, the receiving includes: receiving a service request message from a session management function of the home public land mobile network at a session management function of the target public land mobile network, the service request message including at least one of: information related to the protocol data unit session establishment request, or subscription data related to the user equipment.

[0034] In some aspects, the receiving comprises: receiving, at the session management function of the target public land mobile network, a protocol data unit session establishment request message from a session management function of the home public land mobile network; and wherein the method comprises: selecting a user plane function of the target public land mobile network to serve the protocol data unit session; and responding to the session management function of the home public land mobile network with an indication of the selected user plane function of the target public land mobile network.

[0035] In some aspects, receiving, at the target public land mobile network, signaling to establish a protocol data unit session for the first service for the user equipment includes receiving the signaling to establish a protocol data unit session for the first service for the user equipment from the visited public land mobile network.

[0036] In some aspects, the method includes: obtaining session management subscription data from a unified data management function of the home public land mobile network, the session management subscription data including at least one of the following according to the data network name: an indication of whether the data network name supports roaming value-added service routing to a target public land mobile network, or an identifier of the target public land mobile network.

[0037] According to one aspect, a device is provided, comprising: at least one processor, and at least one memory, wherein the at least one memory stores instructions, which, when executed by the at least one processor, cause the device to perform: determining whether to route signaling for establishing a protocol data unit session for a first service for a user equipment to a target public land mobile network based on at least one of the following: a data network name associated with the first service, subscription data associated with the user equipment, or an identifier of a visited public land mobile network serving the user equipment, wherein the user equipment is registered with the visited public land mobile network, wherein the first service can be hosted by the target public land mobile network and a home public land mobile network; and based on the determination, routing the signaling for establishing the protocol data unit session at the target public land mobile network.

[0038] In some aspects, routing signaling used to establish the protocol data unit session includes forwarding a network function discovery request from the visited public land mobile network to the target public land mobile network based on at least one of: a data network name associated with the first service, subscription data associated with the user equipment, or an identifier of a visited public land mobile network serving the user equipment.

[0039] In some aspects, the apparatus is caused to perform: using a stored configuration at a network repository function of the home public land mobile network, the stored configuration comprising an indication of a serving public land mobile network and a data network name mapped to a target public land mobile network.

[0040] In some aspects, the device is caused to perform: receiving a protocol data unit session establishment request for the user equipment from the visited public land mobile network at the session management function of the home public land mobile network; and providing a service request message to the session management function of the target public land mobile network based on the protocol data unit session establishment request, the service request message including at least one of the following: information associated with the protocol data unit session establishment request, or subscription data associated with the user equipment.

[0041] In some aspects, the apparatus is caused to perform: controlling, by a session management function of the home public land mobile network, a user plane function of the target public land mobile network by encapsulating an N4 message in a service request message from the session management function of the home public land mobile network to a session management function of the target public land mobile network.

[0042] In some aspects, the apparatus is caused to perform: storing session management subscription data for the user equipment at a unified data management function of the home public land mobile network, the session management subscription data comprising at least one of the following: a data network name having an indication of supporting roaming value-added service routing, or a target public land mobile network identifier having an indication of supporting roaming value-added service routing.

[0043] In some aspects, the apparatus is caused to perform: storing session management function selection subscription data at a unified data management function of the home public land mobile network, the session management function selection subscription data including at least one of the following according to the data network name: an indication of whether the data network name supports roaming value-added service routing to a target public land mobile network, or an identifier of the target public land mobile network; and providing the session management function selection subscription data for the user equipment to the target land mobile network based on a request received from the session management function of the target public land mobile network.

[0044] According to one aspect, a method is provided, comprising: determining whether to route signaling for establishing a protocol data unit session for a first service for a user equipment to a target public land mobile network based on at least one of: a data network name associated with the first service, subscription data associated with the user equipment, or an identifier of a visited public land mobile network serving the user equipment, wherein the user equipment is registered with the visited public land mobile network, wherein the first service can be hosted by the target public land mobile network and a home public land mobile network; and routing signaling for establishing the protocol data unit session at the target public land mobile network based on the determination.

[0045] In some aspects, routing signaling used to establish the protocol data unit session includes forwarding a network function discovery request from the visited public land mobile network to the target public land mobile network based on at least one of: a data network name associated with the first service, subscription data associated with the user equipment, or an identifier of a visited public land mobile network serving the user equipment.

[0046] In some aspects, the method includes using, at a network repository function of the home public land mobile network, a stored configuration including an indication of a serving public land mobile network and a data network name mapped to a target public land mobile network.

[0047] In some aspects, the method includes: receiving, at a session management function of the home public land mobile network, a protocol data unit session establishment request for the user equipment from the visited public land mobile network; and providing, based on the protocol data unit session establishment request, a service request message to the session management function of the target public land mobile network, the service request message including at least one of the following: information associated with the protocol data unit session establishment request, or subscription data associated with the user equipment.

[0048] In some aspects, the method includes controlling, by a session management function of the home public land mobile network, a user plane function of the target public land mobile network by encapsulating an N4 message in a service request message from the session management function of the home public land mobile network to a session management function of the target public land mobile network.

[0049] In some aspects, the method includes: storing session management subscription data for the user equipment at a unified data management function of the home public land mobile network, the session management subscription data including at least one of the following: a data network name with an indication of supporting roaming value-added service routing, or a target public land mobile network identifier with an indication of supporting roaming value-added service routing.

[0050] In some aspects, the method includes: storing session management function selection subscription data at a unified data management function of the home public land mobile network, the session management function selection subscription data including at least one of the following according to the data network name: an indication of whether the data network name supports roaming value-added service routing to a target public land mobile network, or an identifier of the target public land mobile network; and providing the session management function selection subscription data for the user equipment to the target land mobile network based on a request received from the session management function of the target public land mobile network.

[0051] According to one aspect, a computer program comprising instructions is provided, which, when executed by an apparatus, causes the apparatus to perform at least the following operations: receiving, at a target public land mobile network, signaling for establishing a protocol data unit session for a first service for a user equipment, wherein the first service can be hosted by the target public land mobile network and a home public land mobile network; and causing data associated with the protocol data unit session for the first service to be transmitted between the target public land mobile network and a visited public land mobile network, wherein the user equipment is registered with the visited public land mobile network.

[0052] According to one aspect, a computer program comprising instructions is provided, which, when executed by an apparatus, causes the apparatus to perform at least the following operations: determining whether to route signaling for establishing a protocol data unit session for a first service for a user equipment to a target public land mobile network based on at least one of the following: a data network name associated with the first service, subscription data associated with the user equipment, or an identifier of a visited public land mobile network serving the user equipment, wherein the user equipment is registered with the visited public land mobile network, wherein the first service can be hosted by the target public land mobile network and a home public land mobile network; and routing signaling for establishing the protocol data unit session at the target public land mobile network based on the determination.

[0053] According to one aspect, a system is provided, comprising: a device for determining, at a home public land mobile network, whether to route signaling for establishing a protocol data unit session for a first service for a user equipment to a target public land mobile network based on at least one of the following: a data network name associated with the first service, subscription data associated with the user equipment, or an identifier of a visited public land mobile network serving the user equipment, wherein the user equipment is registered with the visited public land mobile network, wherein the first service can be hosted by the target public land mobile network and the home public land mobile network; a device for routing signaling for establishing the protocol data unit session at the target public land mobile network from the home public land mobile network to the target public land mobile network based on the determination; and a device for causing data associated with the protocol data unit session for the first service to be transmitted between the target public land mobile network and the visited public land mobile network at the target public land mobile network, wherein the user equipment is registered with the visited public land mobile network.

[0054] According to one aspect, a system is provided, comprising: a first apparatus, comprising: at least one processor, and at least one memory, the at least one memory storing instructions, the instructions, when executed by the at least one processor, causing the apparatus to perform: determining, at a home public land mobile network, whether to route signaling for establishing a protocol data unit session for a first service of a user equipment to a target public land mobile network based on at least one of: a data network name associated with the first service, subscription data associated with the user equipment, or an identification of a visited public land mobile network serving the user equipment, wherein the user equipment is registered with the visited public land mobile network, wherein the first service can be provided by the target public land mobile network; land mobile network and the home public land mobile network hosting; and based on the determination, routing signaling for establishing the protocol data unit session at the target public land mobile network from the home public land mobile network to the target public land mobile network; a second device, comprising: at least one processor, and at least one memory, the at least one memory storing instructions, the instructions when executed by the at least one processor causing the device to perform: at the target public land mobile network, causing data associated with the protocol data unit session for the first service to be transmitted between the target public land mobile network and a visited public land mobile network, wherein the user equipment is registered with the visited public land mobile network.

[0055] According to one aspect, a method is provided, comprising: determining, at a home public land mobile network, whether to route signaling for establishing a protocol data unit session for a first service for a user equipment to a target public land mobile network based on at least one of the following: a data network name associated with the first service, subscription data associated with the user equipment, or an identifier of a visited public land mobile network serving the user equipment, wherein the user equipment is registered with the visited public land mobile network, wherein the first service can be hosted by the target public land mobile network and the home public land mobile network; based on the determination, routing signaling for establishing the protocol data unit session at the target public land mobile network from the home public land mobile network to the target public land mobile network; and at the target public land mobile network, causing data associated with the protocol data unit session for the first service to be transmitted between the target public land mobile network and the visited public land mobile network, wherein the user equipment is registered with the visited public land mobile network.

[0056] According to one aspect, a device is provided, comprising: a device for receiving, at a network repository function of a home public land mobile network, a request for network function discovery associated with a first service for a user equipment from a visited public land mobile network; a device for determining whether to route the request to a target public land mobile network based on at least one of: a data network name associated with the first service, or an identifier of a visited public land mobile network serving the user equipment; and a device for routing the request from the visited public land mobile network to the network repository function of the target public land mobile network based on the determination.

[0057] According to one aspect, a device is provided, comprising: at least one processor, and at least one memory, wherein the at least one memory stores instructions, which, when executed by the at least one processor, cause the device to perform: receiving, at a network repository function of a home public land mobile network, a request for network function discovery associated with a first service for a user equipment from a visited public land mobile network; determining whether to route the request to a target public land mobile network based on at least one of the following: a data network name associated with the first service, or an identifier of a visited public land mobile network serving the user equipment; and routing the request from the visited public land mobile network to the network repository function of the target public land mobile network based on the determination.

[0058] According to one aspect, a method is provided, comprising: receiving, at a network repository function of a home public land mobile network, a request for network function discovery associated with a first service for a user equipment from a visited public land mobile network; determining whether to route the request to a target public land mobile network based on at least one of: a data network name associated with the first service, or an identifier of a visited public land mobile network serving the user equipment; and routing the request from the visited public land mobile network to a network repository function of the target public land mobile network based on the determination.

[0059] In some aspects, the apparatus comprises: means for accessing the data network name associated with the first service and the identification of a visited public land mobile network serving the user equipment. In an example, a first identification of a visited public land mobile network is associated with a first data network name, wherein the first visited public land mobile network associated with the first data network name is mapped to a first target public land mobile network. In an example, the apparatus comprises means for determining whether the request is associated with the first data network name and is received from a visited public land mobile network associated with the first identification of the visited public land mobile network; and based on the determination, routing the request to the first target public land mobile network.

[0060] According to one aspect, a device is provided, comprising: a device for storing session management subscription data of a user equipment at a unified data management function of a home public land mobile network, the session management subscription data comprising at least one of the following: a data network name with an indication supporting routing to a target public land mobile network, or an identifier of the target public land mobile network; and a device for providing the session management function of the home public land mobile network with the session management subscription data of the user equipment.

[0061] According to one aspect, a device is provided, comprising: at least one processor, and at least one memory, wherein the at least one memory stores instructions, and when the instructions are executed by the at least one processor, the device performs: storing session management subscription data of a user equipment at a unified data management function of a home public land mobile network, the session management subscription data comprising at least one of the following: a data network name with an indication of supporting routing to a target public land mobile network, or an identifier of the target public land mobile network; and providing the session management subscription data of the user equipment to the session management function of the home public land mobile network.

[0062] According to one aspect, a method is provided, comprising: storing, at a unified data management function of a home public land mobile network, session management subscription data of a user equipment, the session management subscription data comprising at least one of the following: a data network name with an indication supporting routing to a target public land mobile network, or an identifier of the target public land mobile network; and providing the session management subscription data of the user equipment to the session management function of the home public land mobile network.

[0063] According to one aspect, a device is provided, comprising: a device for obtaining, at a session management function of a home public land mobile network, session management subscription data of a user equipment from a unified data management function of the home public land mobile network, the session management subscription data comprising at least one of the following: a data network name with an indication supporting routing to a target public land mobile network, or an identifier of the target public land mobile network; a device for determining the target public land mobile network using at least one of the following: the session management subscription data, or a stored configuration; and a device for invoking a service request towards the session management function of the target public land mobile network based on the determination.

[0064] According to one aspect, a device is provided, comprising: at least one processor, and at least one memory, wherein the at least one memory stores instructions, and when the instructions are executed by the at least one processor, the device performs: obtaining, at a session management function of a home public land mobile network, session management subscription data of a user equipment from a unified data management function of the home public land mobile network, the session management subscription data comprising at least one of the following: a data network name with an indication of supporting routing to a target public land mobile network, or an identifier of the target public land mobile network; determining the target public land mobile network using at least one of the following: the session management subscription data, or a stored configuration; and based on the determination, invoking a service request toward the session management function of the target public land mobile network.

[0065] According to one aspect, a method is provided, comprising: obtaining, at a session management function of a home public land mobile network, session management subscription data of a user equipment from a unified data management function of the home public land mobile network, the session management subscription data comprising at least one of: a data network name with an indication supporting routing to a target public land mobile network, or an identification of the target public land mobile network; determining the target public land mobile network using at least one of: the session management subscription data, or a stored configuration; and invoking a service request towards the session management function of the target public land mobile network based on the determination.

[0066] According to one aspect, an apparatus is provided, comprising means for receiving, at a session management function of a target public land mobile network, a service request from a session management function of a home public land mobile network.

[0067] According to one aspect, an apparatus is provided, comprising: at least one processor, and at least one memory, wherein the at least one memory stores instructions, which when executed by the at least one processor cause the apparatus to perform: receiving, at a session management function of a target public land mobile network, a service request from a session management function of a home public land mobile network.

[0068] According to one aspect, a method is provided that includes receiving, at a session management function of a target public land mobile network, a service request from a session management function of a home public land mobile network.

[0069] According to one aspect, an apparatus is provided, comprising: means for controlling, by a session management function of a home public land mobile network, a user plane function of a target public land mobile network by encapsulating an N4 message in a service request message from the session management function of the home public land mobile network to a session management function of the target public land mobile network.

[0070] According to one aspect, an apparatus is provided, comprising: at least one processor, and at least one memory storing instructions, which, when executed by the at least one processor, cause the apparatus to perform: controlling, by a session management function of a home public land mobile network, a user plane function of a target public land mobile network by encapsulating an N4 message in a service request message from the session management function of the home public land mobile network to a session management function of the target public land mobile network.

[0071] According to one aspect, a method is provided, comprising: controlling, by a session management function of a home public land mobile network, a user plane function of a target public land mobile network by encapsulating an N4 message in a service request message from the session management function of the home public land mobile network to a session management function of the target public land mobile network.

[0072] According to one aspect, a device is provided, comprising: a device for storing session management function subscription selection subscription data at a unified data management function of a home public land mobile network, wherein the session management function subscription selection subscription data includes, according to a data network name, an indication of whether the data network name supports routing to a target public land mobile network, and an identifier of the target public land mobile network; and a device for providing the session management function subscription selection subscription data to an access and mobility management function.

[0073] According to one aspect, a device is provided, comprising: at least one processor, and at least one memory, wherein the at least one memory stores instructions, and when the instructions are executed by the at least one processor, the device performs: storing session management function subscription selection subscription data at a unified data management function of a home public land mobile network, wherein the session management function subscription selection subscription data includes, according to a data network name, an indication of whether the data network name supports routing to a target public land mobile network, and an identifier of the target public land mobile network; and providing the session management function subscription selection subscription data to an access and mobility management function.

[0074] According to one aspect, a method is provided, comprising: storing session management function subscription selection subscription data at a unified data management function of a home public land mobile network, wherein the session management function subscription selection subscription data comprises, according to a data network name, an indication of whether the data network name supports routing to a target public land mobile network, and an identifier of the target public land mobile network; and providing the session management function subscription selection subscription data to an access and mobility management function.

[0075] According to one aspect, a device is provided, the device comprising: a device for receiving session management function subscription selection subscription data at an access and mobility management function of a visited public land mobile network, the session management function subscription selection subscription data comprising, according to a data network name, an indication of whether the data network name supports routing to a target public land mobile network, and an identifier of the target public land mobile network; and a device for determining, based on the session management function selection subscription data during establishment of a protocol data unit session, whether the protocol data unit session is to be routed to the target public land mobile network; a device for discovering the session management function of the target public land mobile network using the identifier of the target public land mobile network based on the determination; and a device for including an instance identifier associated with the session management function of the target public land mobile network and the identifier of the target public land mobile network in a request message toward the session management function of the visited public land mobile network.

[0076] According to one aspect, a device is provided, comprising: at least one processor, and at least one memory, wherein the at least one memory stores instructions, wherein when the instructions are executed by the at least one processor, the device performs: receiving, at an access and mobility management function of a visited public land mobile network, session management function subscription selection subscription data, wherein the session management function subscription selection subscription data comprises, according to a data network name, an indication of whether the data network name supports routing to a target public land mobile network, and an identifier of the target public land mobile network; determining, based on the session management function selection subscription data during establishment of a protocol data unit session, whether the protocol data unit session is to be routed to the target public land mobile network; based on the determination, discovering a session management function of the target public land mobile network using the identifier of the target public land mobile network; and including an instance identifier associated with the session management function of the target public land mobile network and the identifier of the target public land mobile network in a request message toward the session management function of the visited public land mobile network.

[0077] According to one aspect, a method is provided, the method comprising: receiving, at an access and mobility management function of a visited public land mobile network, session management function subscription selection subscription data, the session management function subscription selection subscription data comprising, according to a data network name, an indication of whether the data network name supports routing to a target public land mobile network, and an identifier of the target public land mobile network; determining, based on the session management function selection subscription data during establishment of a protocol data unit session, whether the protocol data unit session is to be routed to the target public land mobile network; based on the determination, discovering a session management function of the target public land mobile network using the identifier of the target public land mobile network; and including an instance identifier associated with the session management function of the target public land mobile network and the identifier of the target public land mobile network in a request message toward the session management function of the visited public land mobile network.

[0078] A computer product stored on a medium may cause an apparatus to perform the method as described herein.

[0079] A non-transitory computer-readable medium comprising program instructions which, when executed by an apparatus, cause the apparatus to perform a method as described herein.

[0080] An electronic device may include an apparatus as described herein.

[0081] In the above, various aspects have been described. It should be understood that other aspects can be provided by combining any two or more of the above various aspects.

[0082] Various other aspects are also described in the following detailed description and claims.

[0083] According to some aspects, the subject matter of the independent claims is provided. Some further aspects are defined in the dependent claims. Example embodiments, if any, that do not fall within the scope of the claims are to be construed as examples that aid in understanding the present disclosure.

[0084] Abbreviations:

[0085] AF: Application Function

[0086] AMF: Access and Mobility Management Function

[0087] AN: Access Network

[0088] BS: Base Station

[0089] CN: Core Network

[0090] DL: Downlink

[0091] eNB: eNodeB

[0092] gNB: gNodeB

[0093] IIoT: Industrial Internet of Things

[0094] LTE: Long Term Evolution

[0095] NEF: Network Exposure Function

[0096] NG-RAN: Next Generation Radio Access Network

[0097] NF:Network Function

[0098] NR: New Radio

[0099] NRF: Network Repository Function

[0100] NW:Network

[0101] MS: Mobile Station

[0102] PCF Policy Control Function

[0103] PLMN: Public Land Mobile Network

[0104] HPLMN: Home Public Land Mobile Network

[0105] TPLMN: Target Public Land Mobile Network

[0106] VPLMN: Visited Public Land Mobile Network

[0107] RAN: Radio Access Network

[0108] RF: Radio Frequency

[0109] RVAS: Roaming Value Added Service

[0110] SMF: Session Management Function

[0111] UE: User Equipment

[0112] UDR: Unified Data Repository

[0113] UDM: Unified Data Management

[0114] UL: Uplink

[0115] UPF: User Plane Function

[0116] 3GPP: Third Generation Partnership Project

[0117] 5G: Fifth Generation

[0118] 5GC: 5G Core Network

[0119] 5G-AN: 5G Radio Access Network

[0120] 5GS: 5G System BRIEF DESCRIPTION OF THE DRAWINGS

[0121] Some example embodiments will now be described, by way of illustrative and non-limiting examples only, and with reference to the accompanying drawings, in which:

[0122] Figure 1 A schematic diagram of a 5G system is shown;

[0123] Figure 2 A schematic diagram of a control device is shown;

[0124] Figure 3 shows a schematic diagram of a terminal;

[0125] Figure 4 A schematic diagram showing a wireless communication system having a home public land mobile network, a visited public land mobile network, a target public land mobile network, and a roaming user equipment;

[0126] Figure 5 A schematic diagram showing interfaces between network functions of a visited public land mobile network, a home public land mobile network, and a target public land mobile network;

[0127] Figure 6 An example signaling flow diagram between network functions of a visited public land mobile network, a home public land mobile network, and a target public land mobile network is shown;

[0128] Figure 7 A schematic diagram showing interfaces between network functions of a visited public land mobile network, a home public land mobile network, and a target public land mobile network;

[0129] Figure 8 An example signaling flow diagram between network functions of a visited public land mobile network, a home public land mobile network, and a target public land mobile network is shown;

[0130] Fig. 9 A schematic diagram showing interfaces between network functions of a visited public land mobile network, a home public land mobile network, and a target public land mobile network;

[0131] Fig.10a and 10b shows an example signaling diagram between network functions of a visited public land mobile network, a home public land mobile network, and a target public land mobile network;

[0132] Fig.11 An example method flow performed by an apparatus is shown;

[0133] Fig.12 An example method flow performed by an apparatus is shown;

[0134] Fig.13 An example method flow performed by the system is shown;

[0135] Fig.14 An example method flow performed by an apparatus is shown;

[0136] Fig.15a and 15b An example method flow is shown, each of which is performed by a device;

[0137] Fig.16a and 16b An example method flow is shown, each of which is performed by a device;

[0138] Fig.17a and 17b An example method flow is shown, each of which is performed by a device;

[0139] Fig.18 A schematic diagram of a non-volatile storage medium is shown, which stores instructions that, when executed by a processor, allow the processor to perform Figures 11 to 17b One or more steps of a method. DETAILED DESCRIPTION

[0140] In the following, various exemplary embodiments of the present disclosure are described with reference to a mobile communication device capable of communicating via a wireless cellular system and a mobile communication system serving such a mobile communication device. Figures 1 to 3 Certain general aspects of wireless communication systems and mobile communication devices are briefly described to aid understanding of the technology upon which the described examples are based.

[0141] Figure 1 A schematic diagram of a wireless communication system 100 is shown. The wireless communication system 100 includes one or more devices 102 such as user equipment (UE) or terminals. The wireless communication system 100 also includes a 5G system (5GS). The 5GS includes a 5G radio access network (5G-RAN) 106, a 5G core network (5GC) 104 including one or more network functions (NFs), one or more application functions (AFs) 108, and one or more data networks (DNs) 110.

[0142] The 5G-RAN 106 may include one or more gNodeB (gNB) distributed unit (DU) functions connected to one or more gNodeB (gNB) centralized unit (CU) functions.

[0143] 5GC 104 includes access management function (AMF) 112, session management function (SMF) 114, authentication server function (AUSF) 116, user data management (UDM) 118, user plane function (UPF) 120, network public function (NEF) 122 and / or other NFs. Some example embodiments described below may be applied to the 3GPP 5G standard. Additionally or alternatively, some example embodiments may be applied to 3G, 4G, 5G-advanced, 6G and other 3GPP standards or non-3GPP standards.

[0144] In a wireless communication system 100 (such as Figure 1 In the wireless communication system 100 shown in FIG. 1 , a mobile communication device / terminal or user equipment, and / or user equipment (UE), and / or machine type communication device is provided with wireless access via at least one base station or similar wireless transmission and / or reception node or access point. The terminal is provided with appropriate signal reception and transmission means for enabling communication (e.g., allowing access to a communication network or communicating directly with other devices). The communication device can access a carrier provided by a base station or access point and send and / or receive communications on the carrier.

[0145] Figure 2 An example of a control device 200 is shown. The control device 200 may be configured to control one or more network entities / network functions (such as Figure 1211b). The control device 200 includes at least one random access memory (RAM) 211a, at least one read-only memory (ROM) 211b, at least one processor 212, 213, and an input / output interface 214. At least one processor 212, 213 is coupled to the RAM 211a and the ROM 211b. At least one processor 212, 213 may be configured to execute appropriate software code 215. For example, the software code 215 may allow the execution of various example embodiments of the present disclosure. The software code 215 may be stored in the ROM 211b. The control device 200 may be interconnected with another control device 200 that controls another entity / function of the 5G-AN or 5GC. In some example embodiments, each function of the 5G-AN or 5GC includes a control device 200. In an alternative example embodiment, two or more functions of the 5G-AN or 5GC may share a control device. The control device 200 may include one or more circuits or circuit systems (not shown) that may be configured to execute one or more example embodiments.

[0146] Figure 3 The terminal 300 (such as Figure 1 ) as an example of a terminal shown in . The terminal 300 may be provided by any device capable of sending and receiving radio signals. Illustrative and non-limiting examples of terminals include user equipment, a mobile station (MS) or a mobile device (such as a mobile phone or a so-called 'smart phone'), a computer with a wireless interface card or other wireless interface facility (e.g., a USB dongle), a personal digital assistant (PDA) or tablet computer with wireless communication capabilities, a machine type communication (MTC) device, a cellular Internet of Things (CIoT) device, or any combination of these items, etc. The terminal 300 may, for example, provide data communications for bearer communications. The communications may be one or more of voice, electronic mail (email), text messaging, multimedia, data, machine data, etc.

[0147] The terminal 300 may receive signals via an air interface or radio interface 307 via appropriate means for receiving, and may transmit signals via appropriate means for transmitting radio signals. Figure 3 In the mobile device, the transceiver arrangement is schematically represented by block 306. The transceiver arrangement 306 may be provided, for example, by means of a radio part and associated antenna arrangement. The antenna arrangement may be arranged internally or externally to the mobile device.

[0148] The terminal 300 may be provided with at least one processor 301, at least one memory ROM 302a, at least one RAM 302b and other possible components 303, for performing the tasks it is designed to perform with the assistance of software and hardware, including controlling access to access systems and other communication devices and communication with access systems and other communication devices. At least one processor 301 is coupled to RAM 302b and ROM 302a. At least one processor 301 may be configured to execute appropriate software code 308. For example, software code 308 may allow execution of one or more of the various exemplary embodiments of the present disclosure. Software code 308 may be stored in ROM 302a. The terminal 300 may include one or more circuits or circuit systems (not shown) that may be configured to execute one or more of the various exemplary embodiments of the present disclosure.

[0149] The processor, storage and other related control means may be provided on an appropriate circuit board and / or in a chipset. This feature is indicated by reference numeral 304. The device may optionally have a user interface, such as a keypad 305, a touch-sensitive screen or touchpad, a combination thereof, or the like. Optionally, one or more of a display, a speaker and a microphone may be provided, depending on the type of device.

[0150] In wireless communications, a public land mobile network (PLMN) is a combination of wireless communication services provided by a specific operator (e.g., a mobile network operator (MNO)) in a specific country. A PLMN typically includes multiple cellular technologies (e.g., 5G / NR, LTE / 4G, etc.) provided by a single operator within a given country, and is commonly referred to as a cellular network. A PLMN can be identified by a globally unique PLMN code, which may include an MCC (Mobile Country Code) and an MNC (Mobile Network Code).

[0151] Information associated with a user or user equipment, such as an International Mobile Subscriber Identifier (IMSI), may be used to determine a Home PLMN (HPLMN). A user / UE has a HPLMN in which the user profile is configured. When roaming, the user / UE changes its location, which may change its roaming PLMN. The new PLMN may be the same as the HPLMN or a PLMN of its other network. When roaming, the user attaches to a core network via an access network. The roaming core network belongs to the PLMN. This is called a Visited VPLMN (VPLMN). The VPLMN and the HPLMN may be the same or different, depending on the location of the user / UE and the serving MNO.

[0152] 3GPP is studying the potential requirements for supporting roaming value-added services (RVAS) in future studies (e.g., in 3GPP TR 22.877). An RVAS provider may be an external entity that performs actions outside the boundaries of the MNO's network domain to provide RVAS services to the MNO. The services provided may include services for the service user (e.g., roaming control services, roaming welcome messages) or services for the service network (e.g., to resolve interoperability issues, corrective actions).

[0153] It has been recognized that there may be problems when a user / UE roams from a home country to a roaming country. For example, there may be a multi-country operator (e.g., MNO 1). MNO 1 may have two or more PLMN IDs. For example, 'MNO 1 India' and 'MNO 1 Sri Lanka'. A UE of MNO 1 India may roam in Sri Lanka (i.e., MNO 1 India is the HPLMN of the UE). The UE may be registered to any VPLMN in Sri Lanka. For example, the UE has subscribed to 'Service X' hosted by MNO 1. Service X is hosted by both 'MNO 1 India' and 'MNO 1 Sri Lanka'. When the UE is roaming in Sri Lanka and registered to the VPLMN, if the UE wants to access Service X, the UE will establish a Home Routing (HR) Protocol Data Unit (PDU) session to its home network (i.e., MNO 1 India). However, the HRPDU session established between Sri Lanka and India means that the communication of the PDU session must travel back and forth to India where the HPLMN is located. Due to the increased latency, this may have a negative impact on the user experience of the UE. Furthermore, traffic routing between countries results in a higher variance in traffic failures.

[0154] One or more of the various example embodiments described herein are directed to addressing one or more of the above-identified problems.

[0155] In some example embodiments, an apparatus is provided, which is configured to receive, at a target public land mobile network, signaling for establishing a protocol data unit session for a first service for a user equipment, wherein the first service can be hosted by the target public land mobile network and a home public land mobile network. The apparatus is also configured to cause data associated with the protocol data unit session for the first service to be transmitted between the target public land mobile network and a visited public land mobile network, wherein the user equipment is registered with the visited public land mobile network. Other aspects of this example embodiment and other example embodiments will be described in more detail below.

[0156] Figure 4 A schematic diagram of a wireless communication system with a home public land mobile network, a visited public land mobile network, a target public land mobile network, and a roaming user equipment is shown.

[0157] exist Figure 4 In a system 400, a UE 401 (UE-A) is provided with a 'home' country (e.g., India). A 'roaming' country (e.g., Sri Lanka) is also provided. The home country has an HPLMN 403 and the roaming country has a VPLMN 405. UE-A 401 is roaming in the VPLMN 405. Based on the example problem discussed above, MNO 1 India may be associated with the HPLMN 403, while MNO 1 Sri Lanka may be associated with the VPLMN 405.

[0158] Some services may be provided to UE-A 401 using a Home Routing (HR) PDU session between VPLMN 405 and HPLMN 403. As discussed above, this may result in high latency for the session.

[0159] A data network (DN) 407 is provided in the roaming country. UE-A 401 can access some services using a local breakout (LBO) PDU session to DN 407. For the LBO PDU session, the session will be managed by VPLMN 403.

[0160] exist Figure 4 In the example, MNO 1 Sri Lanka and MNO 1 India are both capable of hosting ‘Service X’. A target PLMN (TPLMN) 409 is provided. TPLMN 409 is capable of hosting ‘Service X’. TPLMN 409 is configured to establish a PDU session for ‘Service X’ for UE-A 401, where ‘Service X’ can be hosted by TPLMN 407 and HPLMN 403. After the PDU session is established, TPLMN 409 is capable of sending and receiving data associated with the PDU session for Service X between TPLMN 407 and VPLMN 405. That is, downlink data of the PDU session is provided from TPLMN 409 to VPLMN 405, and uplink data of the PDU session is provided from VPLMN 405 to TPLMN 409.

[0161] When the UE is roaming in Sri Lanka, it can be beneficial for the user experience (e.g. latency, throughput, etc.) that a specific service (e.g., 'Service X') is provided by the T-PLMN 409 of MNO 1 Sri Lanka (rather than MNO 1 India). Since the traffic needs to cross the country border (between India and Sri Lanka), intra-country traffic routing makes the service less prone to failure. In this way, a mechanism is provided where PDU sessions specific to Service-X are served by the target PLMN 409 (i.e., MNO 1 Sri Lanka), while PDU sessions for other services still use home routing (to MNO 1 India) or LBO. Some services (e.g., Service X) for one user (e.g., UE-A 401) or a group of users are handled by the target PLMN 409 instead of the HPLMN 403, where the determination of which entity / network should provide the service is based on the UE's subscription data and the current serving PLMN.

[0162] Further aspects of this and some other example embodiments are described in further detail below.

[0163] In some example embodiments, the HPLMN's NRF (H-NRF) is configured to forward an H-SMF (SMF of the HPLMN) discovery request from the VPLMN to the TPLMN based on a data network name (DNN) and an identity of the VPLMN (VPLMN ID). The DNN and / or VPLMN ID may be locally configured in the HPLMN's NRF. For example, the VPLMN NRF sends a discovery request to the HPLMN NRF to discover the H-SMF. The HPLMN NRF has such a stored configuration / is able to access such a configuration: when an SMF discovery request for a specific DNN (e.g., DNN "Y") is received from a VPLMN with a specific VPLMN ID (e.g., VPLMN ID "X"), the request is forwarded to the TPLMN. The TPLMN is determined based on the VPLMN ID. The TPLMN then provides information about the TPLMN's SMF (T-SMF) to the VPLMN, which establishes a PDU session for the (requested) DNN. The TPLMN then selects the UPF of the TPLMN (T-UPF) to serve the PDU session. After the PDU session is established, uplink data and downlink data are transmitted between the VPLMN and the TPLMN. In this example embodiment, the HPLMN is not involved in the data transmission (uplink and downlink) of the PDU session. Figure 5 and Figure 6 Other aspects of this example embodiment and some other example embodiments are described together in more detail.

[0164] In some example embodiments, the SMF of the HPLMN SMF (H-SMF) is configured to invoke services of the SMF (T-SMF) toward the TPLMN when the H-SMF receives a PDU session establishment request for a UE from the SMF (V-SMF) of the VPLMN, wherein the DNN is enabled for routing to the TPLMN of the VPLMN. The session establishment request includes PDU session information provided by the VPLMN, and subscription data of the UE retrieved from the UDM. The UDM is associated with the HPLMN. In an alternative example embodiment, the T-SMF downloads the subscription data from the UDM. The T-SMF processes the session establishment request, and selects the UPF (T-UPF) of the TPLMN to service the PDU session, and returns a response to the H-SMF. In response to receiving the response from the T-SMF, the H-SMF provides a response to the V-SMF. Signaling exchanged for managing the PDU session that has been established between the VPLMN and the TPLMN occurs via the HPLMN. After the PDU session is established, uplink data and downlink data are transmitted between the VPLMN and the TPLMN. In this example embodiment, the HPLMN is not involved in the data transmission (uplink and downlink) of the PDU session. Figure 7 and Figure 8 Other aspects of this example embodiment and some other example embodiments are described together in more detail.

[0165] In some example embodiments, subscription data associated with the UE (which can be used for SMF selection) is provided in accordance with the VPLMN and stored in the UDM, wherein the subscription data includes at least one of the following indications in accordance with the DNN: i) whether the DNN is enabled for routing to the TPLMN, ii) the TPLMN ID. In the UDM, different UE subscription data can be stored. For example, at least one of the following: access and mobility subscription data, session management subscription data, or SMF selection subscription data. In some example embodiments, the SMF selection subscription data can be stored / included in accordance with the indication of the DNN. During the establishment of the PDU session, based on the subscription data, the AMF (V-AMF) of the VPLMN determines that the PDU session will be routed to the TPLMN. The V-AMF uses the TPLMN ID associated with the TPLMN to discover the T-SMF. The discovered T-SMF will act as the H-SMF for the (home-routed) PDU session. The V-AMF includes the T-SMF and TPLMN ID in the Nsmf_PDUSession_CreateSMContext request to the V-SMF. The V-SMF sends Nsmf_PDUSession_CreateSMContext to the selected T-SMF. In some example embodiments, this may be followed by other steps, such as the procedure specified in clause 4.3.2.2.2 of 3GPP TS 23.502. Once the HR PDU session is established, the H-SMF and H-UPF are replaced by the T-SMF and T-UPF (e.g., the PDU session is established between the TPLMN and the VPLMN). Together with Fig. 9 , Fig.10a and Fig.10b Other aspects of this example embodiment and some other example embodiments are described together in more detail.

[0166] Figure 5 A schematic diagram showing interfaces between network functions of a visited public land mobile network, a home public land mobile network, and a target public land mobile network is shown.

[0167] Figure 5 Shown above Figure 1 , wherein the network functions are associated with each of the VPLMN 501, the HPLMN 503, and the TPLMN 505. Figure 5 In the example embodiment of , UE 507 is roaming and registered with VPLMN 501.

[0168] like Figure 5As shown, the NRF of the HPLMN (H-NRF) 509 is configured to select the NRF of the TPLMN (T-NRF) 511 and send a discovery request query to the T-NRF. In this way, the H-NRF 509 interfaces with the T-NRF 511. In some example embodiments, the H-NRF 509 selects the T-NRF 511 based on the DNN and the serving PLMN ID. The SMF of the TPLMN (T-SMF) 513 is able to obtain subscription data from the UDM 515 of the HPLMN (UDM).

[0169] In some example embodiments, enhancements to SMF selection by the AMF during an HR PDU session are provided. UE requested PDU session establishment for home routed roaming scenarios (e.g., procedures associated with clause 4.3.2.2.2 of TS 23.502) may be performed.

[0170] For SMF selection, the AMF selects an SMF in the HPLMN using the single network slice association information (S-NSSAI) of the HPLMN for the PDU session. In some example embodiments, this step is performed in addition to the step performed at step 2 described in clause 4.3.2.2.3 of TS23.502.

[0171] In some example embodiments, enhancements to HPLMN SMF selection (eg, related to clause 4.3.2.2.3 of TS 23.502) are provided.

[0172] When the NRF (hNRF) of the HPLMN receives the Nnrf_NFDiscovery_Request, the hNRF determines that the received query should be forwarded to the T-NRF based on the DNN and the serving PLMN ID. The hNRF triggers "NF Discovery" to the T-NRF on behalf of the V-AMF. The hNRF uses local configuration for mapping the serving PLMN and the DNN to the target PLMN. The T-NRF then provides information about the set of T-SMF instances to the hNRF in the Nnrf_NFDiscovery_Request response message. In some example embodiments, these steps are performed at step 6 of 4.3.2.2.3.3-1 in TS23.502 or at step 2 of 4.3.2.2.3.3-2. Thereafter, the SMF selection is completed, where the H-SMF is replaced by the T-SMF for the PDU session, and the H-UPF is replaced by the T-UPF. In this way, the T-SMF plays the role of the H-SMF, and the T-UPF plays the role of the H-UPF.

[0173] In some example embodiments, before sending the Nsmf_PDUSession_Create request, when the V-SMF sends a T-SMF discovery request to the vNRF (and hNRF) based on the T-SMF instance ID received from the V-AMF, the hNRF uses the same local configuration (e.g., based on the DNN and serving PLMN ID) to determine that the query is to be forwarded to the T-NRF to obtain the NF profile of the T-SMF that matches the NF instance ID.

[0174] The PCF and UDM remain at the home PLMN, which means that the T-SMF can obtain session management (SM) subscription data from the H-UDM. The T-SMF can also register with the H-UDM. For SM policies, the T-SMF interacts with the H-PCF.

[0175] Figure 6 An example signaling flow diagram between network functions of a visited public land mobile network, a home public land mobile network, and a target public land mobile network is shown.

[0176] Figure 6 The discovery of the NRF of the TPLMN is shown. When the DNN and VPLMN ID are not configured for RVAS routing, then S603a is followed, as described below (eg, existing behavior). When the DNN and VPLMN ID are configured for RVAS routing, then S603b is followed, as described below.

[0177] exist Figure 6 In the example embodiment of FIG. 5 , it is assumed that the UE is roaming and registered with a VPLMN.

[0178] At S601, the AMF (vAMF) of the VPLMN provides a NF discovery request to the NRF (vNRF) of the VPLMN. In some example embodiments, the NF discovery request may be a Nnrf_NFDiscovery_Request message. In other example embodiments, other suitable messages are used.

[0179] At S602, the vNRF forwards the request to the NRF (hNRF) of the HPLMN.

[0180] In a first alternative (alternative a), when the DNN and VPLMN ID are not configured for RVAS routing, then S603a may be arranged to occur.

[0181] At S603a.1, the hNRF provides a response message to the vNRF. The response message may be a Nnrf_NFDiscovery_Request response. In other example embodiments, other suitable messages are used.

[0182] S603a.2: vNRF forwards the response message to vAMF.

[0183] In a second alternative (alternative b), S603b may be arranged to occur when the DNN and VPLMN ID are configured for RVAS routing.

[0184] At S603b.1, the hNRF forwards the request message to the NRF of the TPLMN (TPLMN NRF).

[0185] The hNRF may forward the NF discovery request based on the VPLMN ID of the VPLMN providing the request and the DNN associated with the request. For example, the VPLMN NRF has sent a discovery request to the HPLMN NRF to discover the H-SMF (e.g., S602). The hNRF has a stored configuration of one or more VPLMN IDs and DNNs. In some example embodiments, the VPLMN ID may be referred to as a serving PLMN ID. When an SMF discovery request for a specific DNN (e.g., DNN "Y") is received from a V-NRF with a specific VPLMN ID (e.g., VPLMN ID "X"), the request is forwarded to the T-NRF. The TPLMN can be determined based on the VPLMN ID.

[0186] In step S603b.2, the TPLMN NRF provides a response message to the hNRF. The response message may be a Nnrf_NFDiscovery_Request response. In other example embodiments, other suitable messages are used.

[0187] At S603b.3, the hNRF forwards the response message to the vNRF.

[0188] At S603b.4, the vNRF forwards the response message to the vAMF.

[0189] The result of the signaling of 'Alternative b' is that the NRF of the TPLMN is discovered and selected for the PDU session. Figure 6 In the Nnrf_NFDiscovery_Request response message, the hNRF can determine that the request (query) should be forwarded to the TPLMN NRF based on the DNN and the serving PLMN ID. The hNRF triggers "NF Discovery" to the TPLMN NRF on behalf of the V-AMF. The hNRF uses the local configuration for the mapping of the serving PLMN and DNN to the TPLMN. The TPLMN NRF then provides the hNRF with information about the set of T-SMF instances in the Nnrf_NFDiscovery_Request response message.

[0190] Figure 7A schematic diagram showing interfaces between network functions of a visited public land mobile network, a home public land mobile network, and a target public land mobile network is shown.

[0191] Figure 7 Shown above Figure 1 , wherein the network function is associated with each of the VPLMN 701, the HPLMN 703, and the TPLMN 705. Figure 7 In the example embodiment of , UE 707 is roaming and registered with VPLMN 701.

[0192] A UDM 709 of the HPLMN 703 is provided. The session management subscription data of the UE stored in the UDM 709 is configured to include at least one of: a DNN marked / indicated for RVAS routing, or a target PLMN ID for RVAS routing.

[0193] The SMF (H-SMF) 711 of the HPLMN 703 is provided. The H-SMF 711 provides / invokes a service request towards the SMF (T-SMF) 713 of the TPLMN 705 based on the target PLMN ID for RVAS routing received in the session management subscription data from the UDM 709. In other example embodiments, instead of the service request, the H-SMF 711 provides an Nsfm_PDUSessionCreate message including the SM subscription data retrieved by the H-SMF from the UDM. Alternatively or additionally, the H-SMF 711 may control the UPF (T-UPF) 715 of the TPLMN 705 via the T-SMF 713 to encapsulate the N4 message in a 'new' service based interface (SBI) message from the H-SMF 711 to the T-SMF 713.

[0194] In some example embodiments, T-SMF 713 receives a service request (or Nsfm_PDUSessionCreate) from H-SMF 711 and is responsible for managing PDU sessions for UE 707. T-SMF 713 registers with UDM 709 and establishes a policy association with PCF (H-PCF) 717 of HPLMN 703.

[0195] In some example embodiments, the T-SMF converts the N4 message encapsulated in the 'new' SBI message into an N4 request towards the T-UPF. In the 5G Core (5GC) network, the N4 interface is a bridge between the control plane and the user plane. In this example embodiment, the H-SMF 711 is managing the PDU session and is also controlling the T-UPF. In this way, the H-SMF 711 registers with the UDM 709 and establishes a policy association with the H-PCF 717.

[0196] Figure 8 An exemplary signaling flow diagram between network functions of a visited public land mobile network, a home public land mobile network, and a target public land mobile network is shown.

[0197] A V-PLMN is provided, the V-PLMN has a V-AMF, a V-SMF and a V-UPF. A H-PLMN is also provided, the H-PLMN has a UDM, an H-SMF and an H-UPF. A T-PLMN is also provided, the T-PLMN has a T-SMF and a T-UPF.

[0198] exist Figure 8 In the example signaling diagram of , it is assumed that the UE is roaming and registered at the VPLMN.

[0199] At S801: UE initiates PDU session establishment. When the UE is roaming, the PDU session may be a home-routed PDU session. As part of establishing the PDU session, signaling exists between the NFs of the VPLMN and the HPLMN. The HPLMN is the home PLMN of the UE.

[0200] For example, the UE may request to initiate a PDU session for a particular service (e.g., also referred to herein as a 'first service'). In this example embodiment, it may be assumed that the first service may be hosted or provided by both the TPLMN and the HPLMN. Based on the serving PLMN to which the UE is registered, the HPLMN determines whether to route signaling to the TPLMN.

[0201] During the establishment process, when the H-SMF obtains the UE's session management subscription data from the UDM (of the HPLMN), the H-SMF determines that the PDU session should be handled at the TPLMN. The determination to route the signaling to the TPLMN may be controlled at the HPLMN based on at least one of the following: the UE's subscription data, information about the DNN that the UE is attempting to access, or the VPLMN ID that is currently serving the UE.

[0202] In some example embodiments, steps 1 to 9 of clause 4.3.2.2.2 of TS 23.502 (eg, HR UE initiated PDU session establishment) may be performed at S801.

[0203] At S802, the H-SMF provides / invokes a service request message towards the T-SMF. The service request may be an SBI message. In other example embodiments, the H-SMF provides a Nsfm_PDUSessionCreate message (instead of a service request) to the T-SMF. The message to the T-SMF includes the information received from the V-SMF in the Nsmf_PDUSessionCreate request and the session management subscription data obtained by the H-SMF from the UDM. In other example embodiments, the T-SMF obtains the SM subscription data from the UDM instead of providing the SM subscription data in the message.

[0204] At S803, based on the message received at the T-SMF, the TPLMN initiates establishment of a PDU session for the UE. The PDU session is established so that the PDU session will be established at the TPLMN.

[0205] In some example embodiments, the T-SMF selects the T-UPF of the TPLMN for the PDU session.

[0206] In some example embodiments, steps 10 to 12c of clause 4.3.2.2.2 of TS 23.502 (eg, HR UE initiated PDU session establishment) may be performed at S803, wherein steps 10 to 12c are performed by the TPLMN.

[0207] At S804: T-SMF provides a response message to H-SMF. In some example embodiments, the response message may be a service request response. In some example embodiments, the response message may be a Nsfm_PDUSessionCreate response message.

[0208] At S805, downlink (DL) data for the PDU session is provided from the TPLMN to the VPLMN. For example, the DL data is provided from the T-UPF of the TPLMN to the V-UPF of the VPLMN.

[0209] At S806 , there may be other signaling for the PDU session between the VPLMN and the HPLMN.

[0210] In some example embodiments, steps 13 to 17 of clause 4.3.2.2.2 of TS 23.502 (eg, HRUE-initiated PDU session establishment) may be performed at S806.

[0211] At S807, uplink (UL) data for the PDU session is provided from the VPLMN to the TPLMN. For example, the UL data is provided from the V-UPF to the T-UPF.

[0212] At S808 , there may be other signaling for the PDU session between the VPLMN and the HPLMN.

[0213] In some example embodiments, steps 18 to 21 of clause 4.3.2.2.2 of TS 23.502 (eg, HRUE-initiated PDU session establishment) may be performed at S808.

[0214] At S809, IPv6 address configuration is provided from the TPLMN to the VPLMN.

[0215] At S810, when an update of the established PDU session is to be provided, the VPLMN provides an update request message to the HPLMN. The update request message may be a Nspm_PDUSessionUpdate request message.

[0216] At S811, the HPLMN forwards the update request message to the TPLMN.

[0217] In some example embodiments, the H-SMF establishes an N4 session with the T-UPF via the T-SMF. A service request / SBI message (e.g., provided from the HPLMN to the TPLMN) may include an N4 message container from the H-SMF to the T-SMF. The T-SMF then sends the N4 message to the T-UPF over the N4 interface. In this way, the N4 message sent from the T-UPF to the T-SMF is then carried to the H-SMF on the SBI message. The H-SMF then controls, for example, Internet Protocol (IP) allocation, event disclosure, quality of service (QoS) control, billing, etc. In this example embodiment, the T-UPF selection is performed by the H-SMF (e.g., instead of the T-SMF).

[0218] In this example embodiment, the UE's subscription data is not sent from the HPLMN to the TPLMN.

[0219] Fig. 9 A schematic diagram showing interfaces between network functions of a visited public land mobile network, a home public land mobile network, and a target public land mobile network is shown.

[0220] Fig. 9 As shown above Figure 1 , wherein the network functions are associated with each of the VPLMN 901, the HPLMN 903, and the TPLMN 905. Fig. 9 In the example embodiment of , UE 907 is roaming and registered with VPLMN 901.

[0221] A UDM 909 of the HPLMN 903 is provided. The SMF selection subscription data may be included in the UDM 909. The SMF selection subscription data may include at least one of the following per DNN: whether the DNN is enabled for RVAS features (e.g., routing to TPLMN), or TPLMN ID. The indication of whether the DNN is enabled for RVAS features may be implemented, for example, as a flag, an indication message, etc.

[0222] The AMF 911 of the VPLMN 901 is provided. Based on the SMF selection subscription data during the PDU session establishment, the V-AMF 911 determines that the PDU session should be routed to the TPLMN 905 (e.g., instead of the H-PLMN 903). The V-AMF 911 uses the TPLMNID to discover the T-SMF 913 (e.g., the T-SMF 913 will act as the H-SMF for the HRPDU session).

[0223] The V-AMF 911 includes the T-SMF NF instance ID and the T-PLMN ID in the Nsmf_PDUSession_CreateSMContext request towards the V-SMF 915.

[0224] The V-SMF 915 uses the TPLMN SMF 913 information and the TPLMN ID information to discover the T-SMF 913 for PDU session establishment. The T-SMF 913 obtains the SM subscription data from the UDM 909 and registers with the UDM 913. For SM policy, the T-SMF 913 interacts with the PCF 917 of the HPLMN.

[0225] Fig.10a and 10b An example signaling diagram between network functions of a visited public land mobile network, a home public land mobile network, and a target public land mobile network is shown.

[0226] for Fig.10a and 10b Signaling, assuming that the UE is roaming and registered with the VPLMN.

[0227] Fig.10a S1001 to S1011 are shown. Fig.10b S1012a to S1024 are shown.

[0228] At S1001, the UE provides a PDU session establishment request to the AMF of the VPLMN.

[0229] In S1002, AMF selects SMF.

[0230] In some example embodiments, based on the SMF selection subscription data obtained / received during PDU session establishment, the AMF determines that the PDU session should be routed to the TPLMN instead of the H-PLMN. The AMF uses the target PLMN ID to discover the T-SMF (which will act as the H-SMF for the HR PDU session).

[0231] At S1003a, the AMF provides a Nsfm_PDUSession_CreateSMContext request to the V-SMF. The AMF may include T-SMF information (e.g., T-SMF NF instance ID) and T-PLMN ID in the Nsmf_PDUSession_CreateSMContext request toward the V-SMF.

[0232] At S1003b, V-SMF provides Nsfm_PDUSession_CreateSMContext response to AMF.

[0233] At S1004, the V-SMF performs UPF selection. The V-SMF uses T-SMF information and / or TPLMN ID information to discover the T-SMF for PDU session establishment.

[0234] At S1005a, the V-SMF provides an N4 session establishment request to the V-UPF.

[0235] At S1005b, the V-UPF provides an N4 session establishment response to the V-SMF.

[0236] At S1006, the V-SMF provides a Nsfm_PDUSession_Create request to the T-SMF.

[0237] In S1007, the T-SMF interacts with the UDM so that the T-SMF obtains the subscription data of the UE. For example, the T-SMF obtains the SM subscription data from the UDM.

[0238] The SMF selective subscription data may be included in the UDM. The SMF selective subscription data may include at least one of the following according to the DNN: whether the DNN is enabled for RVAS features (e.g., routing to TPLMN), or TPLMN ID. The T-SMF may obtain the SMF selective subscription data.

[0239] At S1008 , there is PDU session authentication / authorization.

[0240] At S1009a, the T-SMF performs PCF selection.

[0241] At S1009b, the T-SMF and the (selected) H-PCF perform SM policy association establishment or SMF-initiated SM policy association modification.

[0242] At S1010 , the T-SMF performs UPF selection.

[0243] In S1011, T-SMF and H-PCF interact to perform SM policy association modification initiated by SMF.

[0244] At S1012a, the T-SMF provides an N4 session establishment request to the selected T-UPF.

[0245] At S1012b, the T-UPF provides an N4 session establishment response message to the T-SMF.

[0246] At S1012c, the T-SMF registers with the UDM.

[0247] At this stage, downlink data is provided from T-UPF to V-UPF for PDU session.

[0248] At S1013, the T-SMF provides the V-SMF with a Nsmf_PDUSession_Create response message.

[0249] At S1013a, the V-SMF provides an N4 session modification request to the V-UPF.

[0250] At S1013b, the V-UPF provides an N4 session modification response message to the V-SMF.

[0251] At S1014, Namf_Communication_N1N2Message is transmitted between AMF and V-SMF.

[0252] At S1015, the AMF provides an M2 PDU session request to the RAN.

[0253] At S1016 , the RAN and the UE interact to perform RRC reconfiguration.

[0254] At S1017, the RAN provides an N2 PDU Session Request Confirm message to the AMF.

[0255] At this stage, uplink data is provided from the UE to the V-UPF and then to the T-UPF.

[0256] At S1018, AMF provides a Nsmf_PDUSession_UpdateSMContext request message to V-SMF.

[0257] In S1019a, the V-SMF provides an N4 session modification request to the V-UPF.

[0258] At S1019b, the V-UPF provides an N4 session modification response to the V-SMF.

[0259] At this stage, downlink data is provided from the V-UPF to the UE.

[0260] At S1020, V-SMF provides Nsmf_PDUSession_UpdateSMcontext response to AMF.

[0261] At S1021, V-SMF provides Nsmf_PDUSession_SMContextStatusNotify message to AMF.

[0262] At S1022, there is an IPv6 address configuration from the T-SMF via the T-UPF and the V-UPF to the UE.

[0263] In S1023, the V-SMF provides a Nsmf_PDUSession_Update request to the T-SMF.

[0264] At S1024 , the T-SMF interacts with the UDM to perform an unsubscribe / unregister action.

[0265] It should be understood that together with Figure 5 to Figure 1 0 The example signaling discussed together may be performed in conjunction with each other. Figure 5 to Figure 1 0 are combined, the signaling may be performed in a different order and / or one or more signaling steps may be performed in a different order. In addition, one or more other intermediate signaling steps may be included between any signaling steps described herein.

[0266] One or more of the different example embodiments described herein include enhancements that are obvious to those skilled in the relevant art. By way of illustrative and non-limiting example, one or more of the different example embodiments provide roaming user equipment with the ability to benefit from an improved user experience due to reduced latency and increased throughput, because specific services when roaming are provided from a TPLMN in a country where the user equipment is roaming. Since specific services are hosted by a TPLMN in a roaming country, rather than being routed to a home country (home roaming), uplink data and downlink data are transmitted between a VPLMN and a TPLMN (e.g., in the same country). In addition, intra-country traffic routing can result in services being less prone to failure because it does not need to cross national borders.

[0267] Fig.11An example method flow performed by an apparatus is shown. The apparatus may be configured to operate as a TPLMN. The apparatus may be configured to operate as one or more network functions of the TPLMN. The apparatus may be configured to perform one or more functions of the one or more network functions of the TPLMN.

[0268] At S1101 , the method includes: receiving, at a target public land mobile network, signaling for establishing a protocol data unit session for a first service of a user equipment, wherein the first service can be hosted by the target public land mobile network and a home public land mobile network.

[0269] At S1103 , the method includes causing data associated with a protocol data unit session for a first service to be transmitted between a target public land mobile network and a visited public land mobile network, wherein the user equipment is registered with the visited public land mobile network.

[0270] Fig.12 An example method flow performed by an apparatus is shown. The apparatus may be configured to operate as a HPLMN. The apparatus may be configured to operate as one or more network functions of the HPLMN. The apparatus may be configured to perform one or more functions of the one or more network functions of the HPLMN.

[0271] At S1201, the method includes: determining whether to route signaling for establishing a protocol data unit session for a first service for a user equipment to a target public land mobile network based on at least one of the following: a data network name associated with the first service, subscription data associated with the user equipment, or an identifier of a visited public land mobile network serving the user equipment, wherein the user equipment is registered with the visited public land mobile network, and wherein the first service can be hosted by the target public land mobile network and the home public land mobile network.

[0272] At S1203, the method includes: based on the determination, routing signaling for establishing a protocol data unit session at the target public land mobile network.

[0273] Fig.13 An example method flow performed by a system is shown. The system may include one or more devices of a TPLMN and one or more devices of a HPLMN. Each device may be configured to operate as one or more network functions of the HPLMN and / or the TPLMN. Each device may be configured to perform one or more functions of one or more network functions of the HPLMN and / or the TPLMN.

[0274] At S1301, the method includes: determining, at a home public land mobile network, whether to route signaling for establishing a protocol data unit session for a first service for a user equipment to a target public land mobile network based on at least one of the following: a data network name associated with the first service, subscription data associated with the user equipment, or an identifier of a visited public land mobile network serving the user equipment, wherein the user equipment is registered with the visited public land mobile network, and wherein the first service can be hosted by the target public land mobile network and the home public land mobile network.

[0275] At S1303, the method includes: based on the determination, routing signaling for establishing a protocol data unit session at the target public land mobile network from the home public land mobile network to the target public land mobile network.

[0276] At S1305 , the method includes: at the target public land mobile network, causing data associated with the protocol data unit session of the first service to be transmitted between the target public land mobile network and the visited public land mobile network.

[0277] Fig.14 An example method flow performed by an apparatus is shown. The apparatus may be configured to operate as an NRF of an HPLMN. The apparatus may be configured to perform one or more functions of an NRF of an HPLMN.

[0278] At S1401 , the method includes receiving, at a network repository function of a home public land mobile network, a request for network function discovery associated with a first service for a user equipment from a visited public land mobile network.

[0279] At S1403, the method includes: determining whether to route the request to a target public land mobile network based on at least one of: a data network name associated with the first service, or an identification of a visited public land mobile network serving the user equipment.

[0280] At S1405 , the method includes: based on the determination, routing the request from the visited public land mobile network to a network repository function of the target public land mobile network.

[0281] Fig.15a and 15b Example method flows each executed by an apparatus are shown.

[0282] Fig.15a The apparatus may be configured to operate as a UDM of the HPLMN. The apparatus may be configured to perform one or more functions of a UDM of the HPLMN.

[0283] At S1501, the method includes: storing session management subscription data of a user equipment at a unified data management function of a home public land mobile network, the session management subscription data including at least one of the following: a data network name with an indication of supporting routing to a target public land mobile network, or an identifier of the target public land mobile network.

[0284] At S1503, the method includes providing session management subscription data of the user equipment to a session management function of the home public land mobile network.

[0285] Fig.15b The apparatus may be configured to operate as an SMF of the HPLMN. The apparatus may be configured to perform one or more functions of an SMF of the HPLMN.

[0286] At S1551, the method includes: at a session management function of a home public land mobile network, obtaining session management subscription data of a user equipment from a unified data management function of the home public land mobile network, the session management subscription data including at least one of the following: a data network name having an indication of supporting routing to a target public land mobile network, or an identifier of the target public land mobile network.

[0287] At S1553 , the method includes: determining the target public land mobile network using at least one of: session management subscription data, or a stored configuration.

[0288] At S1555, the method includes invoking a service request towards a session management function of the target public land mobile network based on the determination.

[0289] Fig.16a and 16b Example method flows each executed by an apparatus are shown.

[0290] Fig.16a The device may be configured to operate as a SMF of a TPLMN. The device may be configured to perform one or more functions of a SMF of a TPLMN.

[0291] At S1601 , the method includes: receiving, at a session management function of a target public land mobile network, a service request from a session management function of a home public land mobile network.

[0292] Fig.16b The apparatus may be configured to operate as an SMF of the HPLMN. The apparatus may be configured to perform one or more functions of an SMF of the HPLMN.

[0293] At S1651, the method includes controlling, by the session management function of the home public land mobile network, a user plane function of the target public land mobile network by encapsulating an N4 message in a service request message from the session management function of the home public land mobile network to the session management function of the target public land mobile network.

[0294] Fig.17a and 17b Exemplary method flows each executed by a device are shown.

[0295] Fig.17a The device may be configured to operate as a UDM of a TPLMN. The device may be configured to perform one or more functions of a UDM of a TPLMN.

[0296] At S1701, the method includes: storing session management function subscription selection subscription data at a unified data management function of a home public land mobile network, wherein the session management function subscription selection subscription data includes, according to the data network name, an indication of whether the data network name supports routing to a target public land mobile network, and an identifier of the target public land mobile network.

[0297] At S1703, the method includes: providing the session management function subscription selection subscription data to the access and mobility management function.

[0298] Fig.17b The apparatus may be configured to operate as an AMF of a VPLMN. The apparatus may be configured to perform one or more functions of an AMF of a VPLMN.

[0299] At S1751, the method includes: receiving, at an access and mobility management function of a visited public land mobile network, session management function subscription selection subscription data, the session management function subscription selection subscription data including, according to a data network name, an indication of whether the data network name supports routing to a target public land mobile network, and an identifier of the target public land mobile network.

[0300] At S1753, the method includes determining whether the protocol data unit session is to be routed to the target public land mobile network based on the session management function selection subscription data during the protocol data unit session establishment.

[0301] At S1755 , the method includes: based on the determination, using the identification of the target public land mobile network to discover a session management function of the target public land mobile network.

[0302] At S1757, the method comprises: including the instance identification associated with the session management function of the target public land mobile network and the identification of the target public land mobile network in a request message towards the session management function of the visited public land mobile network.

[0303] Fig.18 Schematic diagram of non-volatile storage media 1800a (e.g., a computer disk (CD) or digital versatile disk (DVD)) and 1800b (e.g., a universal serial bus (USB) memory stick) storing instructions and / or parameters 1102 that, when executed by a processor, allow the processor to perform Figures 11 to 17b One or more steps of a method.

[0304] It is noted that although various example embodiments are described above, many variations and modifications may be made without departing from the scope of the various example embodiments.

[0305] It will be appreciated that while the above concepts have been discussed in the context of 5GS, one or more of these concepts can be applied to other cellular standards and systems.

[0306] Different example embodiments may therefore vary within the scope of the claims. In general, some example embodiments may be implemented in hardware or dedicated circuits, software, logic, or any combination thereof. For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software, which may be executed by a controller, microprocessor, or other computing device, but the different example embodiments are not limited thereto. Although different example embodiments may be illustrated and described as block diagrams, flow charts, or using some other graphical representations, it is well known that the boxes, devices, systems, techniques, or methods described herein may be implemented in hardware, software, firmware, dedicated circuits or logic, general hardware or controllers or other computing devices, or some combination thereof as illustrative and non-limiting examples.

[0307] Different example embodiments may be implemented by computer software stored in a memory and executable by at least one data processor of the entity involved, or by hardware, or by a combination of software and hardware. In addition, in this regard, it should be noted that any process may represent program steps, or interconnected logic circuits, boxes and functions, or a combination of program steps and logic circuits, boxes and functions. The software may be stored on a physical medium such as a memory chip or a storage block implemented in a processor, a magnetic medium such as a hard disk or a floppy disk, and an optical medium such as, for example, a DVD and its data variants, a CD.

[0308] As used herein, the term "non-transitory" is a limitation of the medium itself (eg, tangible, non-signal), as opposed to a limitation on data storage persistence (eg, RAM vs. ROM).

[0309] As used herein, “at least one of: ” and “at least one of: ” and similar expressions (wherein a list of two or more elements is connected by “and” or “or”) mean at least any one of the elements, or at least any two or more of the elements, or at least all of the elements.

[0310] The memory may be of any type suitable for the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based storage devices, magnetic storage devices and systems, optical storage devices and systems, fixed memory, and removable memory. The data processor may be of any type suitable for the local technical environment and may include, by way of illustrative and non-limiting examples, one or more of a general purpose computer, a special purpose computer, a microprocessor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a gate level circuit, and a processor based on a multi-core processor architecture.

[0311] As used herein, the term "means for..." or "means configured to perform..." (or similar terms) may be any device suitable for performing the feature. The "means" may be configured to perform one or more of the previously described functions and / or method steps. For example, the "means" may include one or more of the following: at least one processor, at least one memory, transceiver circuitry, antenna circuitry, etc. It should be understood that these are provided as illustrative and non-limiting examples.

[0312] Alternatively, or in addition, some example embodiments may be implemented using circuits. The circuits may be configured to perform one or more of the previously described functions and / or method steps. The circuits may be provided in a base station and / or a communication device.

[0313] As used herein, the term "circuitry" may refer to one or more or all of the following example embodiments:

[0314] (a) hardware-only circuit implementation (e.g., implementation in analog and / or digital circuits only);

[0315] (b) a combination of hardware circuitry and software, such as:

[0316] (i) a combination of analog and / or digital hardware circuitry and software / firmware, and

[0317] (ii) a hardware processor (including a digital signal processor) with software, software, and any portion of memory that work together to enable an apparatus (such as a communication device or base station) to perform the various functions previously described; and

[0318] (c) A hardware circuit and / or processor, such as a microprocessor or portion of a microprocessor, that uses software (eg, firmware) to operate, but the software may not be present when the software is not required for operation.

[0319] This definition of circuitry applies to all uses of the term herein, including in any claims. As a further example, as used herein, the term "circuitry" also covers an implementation of only a hardware circuit or processor (or multiple processors) or a portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term "circuitry" also covers, for example, an integrated device. For example, and if applicable to a particular claim element, the term "circuitry" also covers a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in a server, cellular network device, or other computing or network device.

[0320] As used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. For example, the expression "device" may therefore refer to a single device or to two or more devices. It will be further understood that when used herein, the terms "comprising", "having", and / or "including" specify the presence of stated aspects within an example embodiment, but do not preclude the presence or addition of one or more other aspects.

[0321] The above description provides a complete and informative description of various example embodiments by way of illustrative and non-limiting examples. However, various modifications and adaptations will become apparent to those skilled in the relevant arts in view of the foregoing description when read in conjunction with the accompanying drawings and claims. However, all such and similar modifications of the teachings will still fall within the scope of the various example embodiments described herein.

Claims

1. A device comprising: at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to perform: receiving, at a target public land mobile network, signaling for establishing a protocol data unit session for a first service for a user equipment, wherein the first service can be hosted by the target public land mobile network and a home public land mobile network; and Data associated with the protocol data unit session for the first service is caused to be transferred between the target public land mobile network and a visited public land mobile network with which the user equipment is registered.

2. A method comprising: receiving, at a target public land mobile network, signaling for establishing a protocol data unit session for a first service for a user equipment, wherein the first service can be hosted by the target public land mobile network and a home public land mobile network; and Data associated with the protocol data unit session for the first service is caused to be transferred between the target public land mobile network and a visited public land mobile network with which the user equipment is registered.

3. A device comprising: at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to perform: determining whether to route signaling for establishing a protocol data unit session for a first service for a user equipment to a target public land mobile network based on at least one of: a data network name associated with the first service, subscription data associated with the user equipment, or an identification of a visited public land mobile network serving the user equipment, wherein the user equipment is registered with a visited public land mobile network, wherein the first service can be hosted by the target public land mobile network and the home public land mobile network; and Based on the determination, signaling for establishing the protocol data unit session is routed at the target public land mobile network.

4. A method comprising: determining whether to route signaling for establishing a protocol data unit session for a first service for a user equipment to a target public land mobile network based on at least one of: a data network name associated with the first service, subscription data associated with the user equipment, or an identification of a visited public land mobile network serving the user equipment, wherein the user equipment is registered with a visited public land mobile network, wherein the first service can be hosted by the target public land mobile network and the home public land mobile network; and Based on the determination, signaling for establishing the protocol data unit session is routed at the target public land mobile network.

5. A device comprising: at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to perform: receiving, at a network repository function of the home public land mobile network, a request for network function discovery associated with a first service for the user equipment from a visited public land mobile network; determining whether to route the request to a target public land mobile network based on at least one of: a data network name associated with the first service, or an identification of a visited public land mobile network serving the user equipment; Based on the determination, the request is routed from the visited public land mobile network to a network repository function of the target public land mobile network.

6. A method comprising: receiving, at a network repository function of the home public land mobile network, a request for network function discovery associated with a first service for the user equipment from a visited public land mobile network; determining whether to route the request to a target public land mobile network based on at least one of: a data network name associated with the first service, or an identification of a visited public land mobile network serving the user equipment; Based on the determination, the request is routed from the visited public land mobile network to a network repository function of the target public land mobile network.

7. A device comprising: at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to perform: storing, at a unified data management function of the home public land mobile network, session management subscription data of the user equipment, the session management subscription data comprising at least one of: a data network name with an indication supporting routing to a target public land mobile network, or an identification of the target public land mobile network; as well as The session management subscription data of the user equipment is provided to a session management function of the home public land mobile network.

8. A method comprising: storing, at a unified data management function of the home public land mobile network, session management subscription data of the user equipment, the session management subscription data comprising at least one of: a data network name with an indication supporting routing to a target public land mobile network, or an identification of the target public land mobile network; as well as The session management subscription data of the user equipment is provided to a session management function of the home public land mobile network.

9. An apparatus comprising: at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to perform: At a session management function of the home public land mobile network, obtaining session management subscription data of the user equipment from a unified data management function of the home public land mobile network, the session management subscription data comprising at least one of the following: a name of a data network having an indication of supporting routing to a target public land mobile network, or an identification of the target public land mobile network; determining a target public land mobile network using at least one of: the session management subscription data, or a stored configuration; as well as Based on the determination, a service request is invoked towards a session management function of the target public land mobile network.

10. A method comprising: At a session management function of the home public land mobile network, obtaining session management subscription data of the user equipment from a unified data management function of the home public land mobile network, the session management subscription data comprising at least one of the following: a name of a data network having an indication of supporting routing to a target public land mobile network, or an identification of the target public land mobile network; determining a target public land mobile network using at least one of: the session management subscription data, or a stored configuration; as well as Based on the determination, a service request is invoked towards a session management function of the target public land mobile network.

11. An apparatus comprising: at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus to perform: storing, at a unified data management function of the home public land mobile network, session management function subscription selection subscription data, wherein the session management function subscription selection subscription data includes, according to the data network name: an indication of whether the data network name supports routing to a target public land mobile network, and an identifier of the target public land mobile network; and The session management function subscription selection subscription data is provided to an access and mobility management function.

12. A method comprising: storing, at a unified data management function of the home public land mobile network, session management function subscription selection subscription data, wherein the session management function subscription selection subscription data includes, according to the data network name: an indication of whether the data network name supports routing to a target public land mobile network, and an identifier of the target public land mobile network; and The session management function subscription selection subscription data is provided to an access and mobility management function.

13. A computer storage medium storing a computer program comprising instructions, which when executed by a device causes the device to perform the method of any one of claims 2, 4, 6, 8, 10, and 12.

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