GB2629841A

GB2629841A - Apparatus, method and computer program

Info

Publication number: GB2629841A
Application number: GB2307052.7A
Authority: GB
Inventors: Chandramouli Devaki; Landais Bruno; Amin Nassar Mohamed
Original assignee: Nokia Technologies Oy
Current assignee: Nokia Technologies Oy
Priority date: 2023-05-12
Filing date: 2023-05-12
Publication date: 2024-11-13
Also published as: WO2024236447A1; CN121128247A; GB202307052D0

Abstract

A method comprising: providing a configuration to a user equipment capable of multiple registrations, the configuration including information that a network function node for managing access to a first network supports multiple registrations. A further method comprises providing an indication, from a second network to a user equipment capable of multiple registrations with one or more networks, that multiple registrations are supported by a network function node for managing access to the second network; and receiving and accepting multiple registration requests from the user equipment at the second network. A third method comprises at least one of the following: (i) receiving, by a user equipment supporting multiple registrations with one or more networks, a configuration including information that a network function node for managing access to a first network supports multiple registrations; or (ii) obtaining, by the user equipment, an indication from a second network that multiple registrations are supported by a network function node for managing access to the second network; and, subsequently, determining, by the user equipment, whether to provide a registration request to the network function node for managing access to the second network based on at least one of the obtained indication or on the received configuration. The indication (within a broadcast message in cells of the second network) includes the number of registrations supported by the second network. The configuration comprises a list of networks for which multiple registrations are supported. The registration request comprises a registration identifier associated with the request.

Description

APPARATUS, METHOD AND COMPUTER PROGRAM

Field

The present application relates to a method, apparatus, system and computer program and in particular but not exclusively to multiple registrations.

Background

A communication system can be seen as a facility that enables communication sessions between two or more entities such as user terminals, base stations and/or other nodes by providing carriers between the various entities involved in the communications path. A communication system can be provided for example by means of a communication network and one or more compatible communication devices. The communication sessions may comprise, for example, communication of data for carrying communications such as voice, video, electronic mail (email), text message, multimedia and/or content data and so on. Non-limiting examples of services provided comprise two-way or multi-way calls, data communication or multimedia services and access to a data network system, such as the Internet.

In a wireless communication system at least a part of a communication session between at least two stations occurs over a wireless link. Examples of wireless systems comprise public land mobile networks (PLMN), satellite based communication systems and different wireless local networks, for example wireless local area networks (WLAN). Some wireless systems can be divided into cells, and are therefore often referred to as cellular systems.

A user can access the communication system by means of an appropriate communication device or terminal. A communication device of a user may be referred to as user equipment (UE) or user device. A communication device is provided with an appropriate signal receiving and transmitting apparatus for enabling communications, for example enabling access to a communication network or communications directly with other users. The communication device may access a carrier provided by a station, for example a base station of a cell, and transmit and/or receive communications on the carrier.

The communication system and associated devices typically operate in accordance with a given standard or specification which sets out what the various entities associated with the system are permitted to do and how that should be achieved. Communication protocols and/or parameters which shall be used for the connection are also typically defined. One example of a communications system is Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (UTRAN) (3G radio). Other examples of communication systems are the long-term evolution (LTE) of the Universal Mobile Telecommunications System (UMTS) radio-access technology and so-called 5G or New Radio (NR) networks. NR is being standardized by the 3rd Generation Partnership Project (3GPP). Other examples of communication systems include 5G-Advanced (NR Rel-18 and beyond) and 6G.

Summary

In a first aspect there is provided an apparatus comprising at least one of the following: means for receiving, by a user equipment supporting multiple registrations with one or more networks, a configuration including information that a network function node for managing access to a first network supports multiple registrations or means for obtaining, by the user equipment, an indication from a second network that multiple registrations are supported by a network function node for managing access to the second network and means for determining, by the user equipment, whether to provide a registration request to the network function node for managing access to the second network based on at least one of the obtained indication or on the received configuration.

The indication may include the number of registrations supported by the second network.

The apparatus may be pre-configured with the information that the network access node for managing access to the first network is capable of supporting multiple registrations or comprises means for receiving the configuration from a home public land mobile network, a visited public land mobile network or a stand-alone non-public network.

The apparatus may comprise means for receiving the indication in a broadcast message in cells of the second network.

The apparatus may comprise means for determining based on the received configuration, that the network function node for managing access to the first network supports multiple registrations and based on the determining, means for providing at least one registration request to the network function node for managing access to the second network based on the indication that the second network supports multiple registrations.

The apparatus may comprise means for providing the at least one registration request to the second network while the user equipment is registered to the same network or a different network.

The apparatus may comprise means for determining based on the received configuration, that the network function node for managing access to the first network supports multiple registrations and based on the determining, means for determining to select or reselect a serving cell belonging to the second network based on the indication that the second network supports multiple registrations.

The configuration may comprise a list of networks for which multiple registrations are supported.

The registration request may comprise a registration identifier associated with the request.

The first network and the second network may be the same network or different networks.

The first network may comprise a home network. The second network may comprise a serving network.

In a second aspect there is provided an apparatus comprising means for providing an indication from a second network to a user equipment capable of multiple registrations with one or more networks that multiple registrations are supported by a network function node for managing access to the second network and means for receiving and accepting multiple registration requests from the user equipment at the second network.

The apparatus may comprise means for providing the indication via a radio access network in a broadcast message.

In a third aspect there is provided an apparatus comprising means for providing a configuration to a user equipment capable of multiple registrations, the configuration including information that a network function node for managing access to a first network supports multiple registrations.

The apparatus may comprise means for providing the configuration to the user equipment from a home public land mobile network via a visited public land mobile network.

In a fourth aspect there is provided a method comprising at least one of the following: receiving, by a user equipment supporting multiple registrations with one or more networks, a configuration including information that a network function node for managing access to a first network supports multiple registrations or obtaining, by the user equipment, an indication from a second network that multiple registrations are supported by a network function node for managing access to the second network and determining, by the user equipment, whether to provide a registration request to the network function node for managing access to the second network based on at least one of the obtained indication or on the received configuration.

The user equipment may be pre-configured with the information that the network access node for managing access to the first network is capable of supporting multiple registrations or the method may comprise receiving the configuration from a home public land mobile network, a visited public land mobile network or a stand-alone non-public network.

The method may comprise receiving the indication in a broadcast message in cells of the second network.

The method may comprise determining based on the received configuration, that the network function node for managing access to the first network supports multiple registrations and based on the determining, providing at least one registration request to the network function node for managing access to the second network based on the indication that the second network supports multiple registrations.

The method may comprise providing the at least one registration request to the second network while the user equipment is registered to the same network or a different network.

The method may comprise determining based on the received configuration, that the network function node for managing access to the first network supports multiple registrations and based on the determining, determining to select or reselect a serving cell belonging to the second network based on the indication that the second network supports multiple registrations.

In a fifth aspect there is provided a method comprising providing an indication from a second network to a user equipment capable of multiple registrations with one or more networks that multiple registrations are supported by a network function node for managing access to the second network and receiving and accepting multiple registration requests from the user equipment at the second network.

The method may comprise providing the indication via a radio access network in a broadcast message.

In a sixth aspect there is provided a method comprising providing a configuration to a user equipment capable of multiple registrations, the configuration including information that a network function node for managing access to a first network supports multiple registrations.

The method may comprise providing the configuration to the user equipment from a home public land mobile network via a visited public land mobile network.

In a seventh aspect there is provided a computer readable medium comprising instructions which, when executed by an apparatus, cause the apparatus to perform at least the following: at least one of the following: receiving, by a user equipment supporting multiple registrations with one or more networks, a configuration including information that a network function node for managing access to a first network supports multiple registrations or obtaining, by the user equipment, an indication from a second network that multiple registrations are supported by a network function node for managing access to the second network and determining, by the user equipment, whether to provide a registration request to the network function node for managing access to the second network based on at least one of the obtained indication or on the received configuration.

The user equipment may be pre-configured with the information that the network access node for managing access to the first network is capable of supporting multiple registrations or the apparatus may be caused to perform receiving the configuration from a home public land mobile network, a visited public land mobile network or a stand-alone non-public network.

The apparatus may be caused to perform receiving the indication in a broadcast message in cells of the second network.

The apparatus may be caused to perform determining based on the received configuration, that the network function node for managing access to the first network supports multiple registrations and based on the determining, providing at least one registration request to the network function node for managing access to the second network based on the indication that the second network supports multiple registrations.

The apparatus may be caused to perform providing the at least one registration request to the second network while the user equipment is registered to the same network or a different network.

The apparatus may be caused to perform determining based on the received configuration, that the network function node for managing access to the first network supports multiple registrations and based on the determining, determining to select or reselect a serving cell belonging to the second network based on the indication that the second network supports multiple registrations.

In an eighth aspect there is provided a computer readable medium comprising instructions which, when executed by an apparatus, cause the apparatus to perform at least the following: providing an indication from a second network to a user equipment capable of multiple registrations with one or more networks that multiple registrations are supported by a network function node for managing access to the second network and receiving and accepting multiple registration requests from the user equipment at the second network.

The apparatus may be caused to perform providing the indication via a radio access network in a broadcast message.

In a ninth aspect there is provided a computer readable medium comprising instructions which, when executed by an apparatus, cause the apparatus to perform at least the following: providing a configuration to a user equipment capable of multiple registrations, the configuration including information that a network function node for managing access to a first network supports multiple registrations.

The apparatus may be caused to perform providing the configuration to the user equipment from a home public land mobile network via a visited public land mobile network.

In a tenth aspect there is provided 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 at least to: at least one of the following: receive, by a user equipment supporting multiple registrations with one or more networks, a configuration including information that a network function node for managing access to a first network supports multiple registrations or obtain, by the user equipment, an indication from a second network that multiple registrations are supported by a network function node for managing access to the second network and determine, by the user equipment, whether to provide a registration request to the network function node for managing access to the second network based on at least one of the obtained indication or on the received configuration.

The apparatus may be pre-configured with the information that the network access node for managing access to the first network is capable of supporting multiple registrations or the apparatus may be caused to receive the configuration from a home public land mobile network, a visited public land mobile network or a stand-alone non-public network.

The apparatus may be caused to receive the indication in a broadcast message in cells of the second network.

The apparatus may be caused to determine based on the received configuration, that the network function node for managing access to the first network supports multiple registrations and based on the determining, provide at least one registration request to the network function node for managing access to the second network based on the indication that the second network supports multiple registrations.

The apparatus may be caused to provide the at least one registration request to the second network while the user equipment is registered to the same network or a different network.

The apparatus may be caused to determine based on the received configuration, that the network function node for managing access to the first network supports multiple registrations and based on the determining, determine to select or reselect a serving cell belonging to the second network based on the indication that the second network supports multiple registrations.

In an eleventh aspect there is provided 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 at least to provide an indication from a second network to a user equipment capable of multiple registrations with one or more networks that multiple registrations are supported by a network function node for managing access to the second network and receive and accept multiple registration requests from the user equipment at the second network.

The apparatus may be caused to provide the indication via a radio access network in a broadcast message.

In a twelfth aspect there is provided 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 at least to provide a configuration to a user equipment capable of multiple registrations, the configuration including information that a network function node for managing access to a first network supports multiple registrations.

The apparatus may be caused to provide the configuration to the user equipment from a home public land mobile network via a visited public land mobile network.

In a thirteenth aspect there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method according to the third or fourth aspect.

In the above, many different embodiments have been described. It should be appreciated that further embodiments may be provided by the combination of any two or more of the embodiments described above.

Description of Figures

Embodiments will now be described, by way of example only, with reference to the accompanying Figures in which: Figure 1 shows a schematic diagram of an example 5GS communication system; Figure 2 shows a schematic diagram of an example mobile communication device; Figure 3 shows a schematic diagram of an example control apparatus; Figure 4 shows a flowchart of a method according to an example embodiment; Figure 5 shows a flowchart of a method according to an example embodiment; Figure 6 shows a flowchart of a method according to an example embodiment; Figure 7 shows a signalling flow according to an example embodiment.

Detailed description

Before explaining in detail the examples, certain general principles of a wireless communication system and mobile communication devices are briefly explained with reference to FIG. 1, FIG. 2 and FIG. 3 to assist in understanding the technology underlying the described examples.

An example of a suitable communications system is the 5G or NR concept. Network architecture in NR may be similar to that of LTE-advanced. Base stations of NR systems may be known as next generation NodeBs (gNBs). Changes to the network architecture may depend on the need to support various radio technologies and finer Quality of Service (QoS) support, and some on-demand requirements for e.g. QoS levels to support Quality of Experience (QoE) for a user. Also network aware services and applications, and service and application aware networks may bring changes to the architecture. Those are related to Information Centric Network (ICN) and User-Centric Content Delivery Network (UC-CDN) approaches. NR may use Multiple Input-Multiple Output (MIMO) antennas, many more base stations or nodes than the LTE (a so-called small cell concept), including macro sites operating in co-operation with smaller stations and perhaps also employing a variety of radio technologies for better coverage and enhanced data rates.

Future networks may utilise network functions virtualization (NFV) which is a network architecture concept that proposes virtualizing network node functions into "building blocks" or entities that may be operationally connected or linked together to provide services. A virtualized network function (VNF) may comprise one or more virtual machines running computer program codes using standard or general type servers instead of customized hardware. Cloud computing or data storage may also be utilized. In radio communications this may mean node operations to be carried out, at least partly, in a server, host or node operationally coupled to a remote radio head. It is also possible that node operations will be distributed among a plurality of servers, nodes or hosts. It should also be understood that the distribution of labour between core network operations and base station operations may differ from that of the LTE or even be non-existent.

FIG. 1 shows a schematic representation of a 5G system (5GS) 100. The 5GS may comprise a user equipment (UE) 102 (which may also be referred to as a communication device or a terminal), a 5G radio access network (5GRAN) 104, a 5G core network (5GCN) 106, one or more internal or external application functions (AF) 108 and one or more data networks (DN) 110.

An example 5G core network (CN) comprises functional entities. The 5GCN 106 may comprise one or more Access and mobility Management Functions (AMF) 112, one or more session management functions (SMF) 114, an authentication server function (AUSF) 116, a Unified Data Management (UDM) 118, one or more user plane functions (UPF) 120, a Unified Data Repository (UDR) 122 and/or a Network Exposure Function (NEF) 124. The UPF is controlled by the SMF (Session Management Function) that receives policies from a PCF (Policy Control Function).

The CN is connected to a UE via the Radio Access Network (RAN). The 5GRAN may comprise one or more gNodeB (gNB) Distributed Unit(DU) functions connected to one or more gNodeB (gNB) Centralized Unit(CU) functions. The RAN may comprise one or more access nodes.

A User Plane Function (UPF) referred to as PDU Session Anchor (PSA) may be responsible for forwarding frames back and forth between the DN and the tunnels established over the 5G towards the UE(s) exchanging traffic with the DN.

A possible mobile communication device will now be described in more detail with reference to FIG. 2 showing a schematic, partially sectioned view of a communication device 200. Such a communication device is often referred to as user equipment (UE) or terminal. An appropriate mobile communication device may be provided by any device capable of sending and receiving radio signals. Non-limiting examples comprise a mobile station (MS) or mobile device such as a mobile phone or what is known as a 'smart phone', a computer provided with a wireless interface card or other wireless interface facility (e.g., USB dongle), personal data assistant (PDA) or a tablet provided with wireless communication capabilities, voice over IP (VoIP) phones, portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), smart devices, wireless customer-premises equipment (CPE), or any combinations of these or the like. A mobile communication device may provide, for example, communication of data for carrying communications such as voice, electronic mail (email), text message, multimedia and so on. Users may thus be offered and provided numerous services via their communication devices. Non-limiting examples of these services comprise two-way or multi-way calls, data communication or multimedia services or simply an access to a data communications network system, such as the Internet. Users may also be provided broadcast or multicast data. Non-limiting examples of the content comprise downloads, television and radio programs, videos, advertisements, various alerts, and other information.

A mobile device is typically provided with at least one data processing entity 201, at least one memory 202 and other possible components 203 for use in software and hardware aided execution of tasks it is designed to perform, including control of access to and communications with access systems and other communication devices. The data processing, storage and other relevant control apparatus can be provided on an appropriate circuit board and/or in chipsets. This feature is denoted by reference 204. The user may control the operation of the mobile device by means of a suitable user interface such as key pad 205, voice commands, touch sensitive screen or pad, combinations thereof or the like. A display 208, a speaker and a microphone can be also provided. Furthermore, a mobile communication device may comprise appropriate connectors (either wired or wireless) to other devices and/or for connecting external accessories, for example hands-free equipment, thereto.

The mobile device 200 may receive signals over an air or radio interface 207 via appropriate apparatus for receiving and may transmit signals via appropriate apparatus for transmitting radio signals. In FIG. 2 transceiver apparatus is designated schematically by block 206. The transceiver apparatus 206 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.

FIG. 3 shows an example of a control apparatus 300 for a communication system, for example to be coupled to and/or for controlling a station of an access system, such as a RAN node, e.g. a base station, eNB or gNB, a relay node or a core network node such as an MME or Serving Gateway (S-GW) or Packet Data Network Gateway (P-GVV), or a core network function such as AM F/SM F, or a server or host. The method may be implemented in a single control apparatus or across more than one control apparatus. The control apparatus may be integrated with or external to a node or module of a core network or RAN. In some embodiments, base stations comprise a separate control apparatus unit or module. In other embodiments, the control apparatus can be another network element such as a radio network controller or a spectrum controller. In some embodiments, each base station may have such a control apparatus as well as a control apparatus being provided in a radio network controller. The control apparatus 300 can be arranged to provide control on communications in the service area of the system. The control apparatus 300 comprises at least one memory 301, at least one data processing unit 302, 303 and an input/output interface 304. Via the interface the control apparatus can be coupled to a receiver and a transmitter of the base station. The receiver and/or the transmitter may be implemented as a radio front end or a remote radio head.

Access Traffic Steering, Switching and Splitting (ATSSS) is a data switching function, which decides how to steer, switch and split uplink traffic across 3GPP and non-3GPP accesses based on the provisioned rules. Rules are transmitted from the network to the UE. UE then adjusts uplink traffic accordingly.

In ATSSS, "steering" refers to the possibility of selecting for user-plane traffic, according to the service (QoS-type for a data flow), the best link to use, "switching" describes the possibility of performing handover without service interruption to the other link when necessary, "splitting" means the simultaneous use (bonding) of the two links.

Access Traffic Steering, Switching and Splitting (ATSSS) allows a 5G System to steer, switch and split traffic among a 3GPP and a non-3GPP access. 3GPP Rel. 18 has recently enabled the coexistence of a 3GPP and temporarily two non-3GPP accesses. Performance measurements between UE and UPF (measuring Round-trip time (RTT), packet loss ratio (PLR), Access Availability/Unavailability) may be taken into consideration for ATSSS decisions.

ATSSS between multiple 3GPP access legs is also being considered by 3GPP for Rel-19.

The concept of dual steer has been introduced in Rel-19. In these cases, the UE is registered simultaneously in 5G Systems multiple times via 3GPP accesses and/or non-3GPP accesses.

Additional use cases and potential service requirements that could benefit from 5GS support of upper layer steering, split and switching of UE's traffic (e.g. pertaining to the same data session) across two 3GPP access links, assuming only single subscription to a public land mobile network (PLMN), are being studied.

Potential scenarios include single PLMN, PLMN plus (standalone) non-public network (NPN), two PLMNs, the same or different 3GPP RATS (NR or Non-Terrestrial network (NTN), plus one of NR, NTN or LTE).

NTN refers to NR-based satellite access, including different orbits (e.g., GEO/MEO/LEO).

For the PLMN plus PLMN/NPN scenarios, the two networks may be managed by the same operator or by different operators (assumed to have a business agreement among them).

For a UE to be registered multiple times in a 5G System, the network (both the Home PLMN (HPLMN) and Visited PLMN (VPLMN) for a roaming UE) must support certain features to ensure that the source NF (e.g. AMF) serving a UE for a specific registration is appropriately cancelled when the UE moves to a target NF.

A UE with the capability for multiple registrations provides a registration ID in each Registration request message. The registration ID acts as an identifier for the registration request and subsequent registration.

An AMF that supports this capability for multiple registrations accepts the registration ID, forwards the registration ID to a UDM to facilitate cancel registration and assigns different 5G-Globally Unique Temporary Identifier (GUTI) for different registration from the same UE.

If a UE tries to camp in a network that does not support this capability, it may be problematic as the network would ignore the registration ID, handle the UE as if it registers at most once for a 3GPP access and once for a non-3GPP access which would result in network misbehavior such as cancelling a wrong UE registration at a wrong AMF (i.e. AMF serving the UE for the wrong registration).

In a first scenario, a UE camps in a gNB and AMF1/PLM N 1, and the UE provides registration ID-1. AMF1 accepts the registration but ignores the registration ID-1 (R1) as AMF1 doesn't support dual/multi registration. AMF1 is registered for the UE in UDM.

The UE camps in a gNB and AMF2/PLMN1, provides registration ID-2. AMF2 accepts the registration but ignores the registration ID-2 as AMF2 doesn't support dual/multi registration.

AMF2 is replaced by AM F1 registration for UE in the UDM as the UDM considers that the UE has moved and the UDM cancels registration in the AMF1, even if UDM itself supports the dual registration feature.

Assuming AMF1, AMF2 are registered in the UDM for the UE. UE moves from AMF1 to AMF3. AMF1 should be cancelled and not AMF2.

Thus, it would be problematic if the UE tries to camp in the network that doesn't support multiple registration capabilities both in the AMF and UDM for a given UE.

In a second scenario, a UE camps in a gNB and AMF1/PLM N 1, and UE provides registration ID-1. AMF1 accepts the registration but ignores the registration ID-1. AMF1 is registered for the UE in the UDM. UE camps in a gNB and AMF2/PLMN2, and UE provides registration ID-2. AMF2 accepts the registration but ignores the registration ID-2 Similar problems as described with respect to the first scenario may occur.

In a third scenario, a UE camps in a gNB and AMF1/PLMN1, and UE provides registration ID- 1. AMF1 accepts the registration and supports handling the registration ID-1. AMF1 is registered for the UE in the UDM. But UDM does not support multiple registrations. UDM ignores the Registration ID-1. The UE camps in a gNB and AMF2/PLMN1, and UE provides registration ID-2. AMF2 accepts the registration and supports handling the registration ID-2.

AMF2 registers for the UE in the UDM but UDM does not support multiple registrations. UDM ignores the Registration ID-2 and cancels the UE registration in AM F1.

One proposal was that the AM F may acknowledge the "registration ID" in the REGISTRATION ACCEPT message to the UE, which indicates to the UE that this AMF supports the multi-registration. The main drawback of this approach is that it happens too late for the UE, i.e. the UE has started the registration assuming multi-registration is supported, while the UE may have other better PLMN choices. Also, the UE may trigger a back-to-back REGISTRATION REQUEST to another AMF without waiting for the REGISTRATON ACCEPT from the first AMF.

Figure 4 shows a flowchart of a method according to an example embodiment. The method may be performed at a user equipment. The UE may comprise a UE such as that described with reference to Figure 2.

In 401, the method comprises at least one of the following: receiving by a user equipment supporting multiple registrations with one or more networks, a configuration including information that a network function node for managing access to a first network supports multiple registrations or obtaining an indication by the user equipment from a second network that multiple registrations are supported by a network function node for managing access to the second network.

In 403, the method comprises determining, by the user equipment, whether to provide a registration request to the network function node for managing access to the second network based on at least one of the obtained indication or on the received configuration.

Figure 5 shows a flowchart of a method according to an example embodiment. The method may be performed at a second network function node, e.g., an AMF. The second network function node may comprise a control apparatus such as that described with reference to Figure 3.

In 501, the method comprises providing an indication from a second network to a user equipment capable of multiple registrations with one or more networks that multiple registrations are supported by the second network.

In 502, the method comprises receiving multiple registration requests from the user equipment at the second network.

Figure 6 shows a flowchart of a method according to an example embodiment. The method may be performed at a network function node, e.g., an AMF of a PLMN or SNPN. The network function node may comprise a control apparatus such as that described with reference to Figure 3.

In 601, the method comprises providing a configuration to a user equipment capable of multiple registrations, the configuration including information that a network function node for managing access to a first network supports multiple registrations.

The apparatus may be pre-configured with the information that a network function node for managing access to a first network is capable of supporting multiple registrations or may comprise means for receiving the configuration from a home public land mobile network, a visited public land mobile network or a stand-alone non-public network.

The first network and the second network may be the same network or may be different networks. The first network may be a HPLMN, a VPLMN or a SNPN. The second network may be a serving network or a network in which a UE is camping.

In an example embodiment, a UE is configured by a HPLMN/VPLMN/SNPN (or pre-configured by a HPLMN/SNPN) regarding the support for multiple registrations (e.g., supported/not supported or allowed/not allowed).

The expression "allowed/not allowed" can be used interchangeably with "supported/not supported" unless specified otherwise.

HPLMN/SNPN may configure or preconfigure the UE to indicate whether multiple registrations to the HPLMN/SNPN is allowed / not allowed e.g. {PLMN ID, multiple registrations allowed or not allowed}.

Ways for a UE to obtain the parameters (e.g., the configuration) it needs to use include obtaining those parameters from the network (e.g. from PCF) using DL (downlink) signalling messages, storing them and using them for future operation or having those parameters pre-configured in the UE. The Pre-configuration of the UE for some parameters means that, the UE is configured to use some specific parameters in the procedures it performs after it powers-on without interacting with the network. Method to pre-configure parameters in the UE include having the parameters pre-configured in the USIM or having the parameters pre-configured as MO (Management Object) in some sort of e.g. non-volatile memory.

Here, multiple registrations configurations (supported/not supported, allowed/not allowed, number Of Allowed Registrations) may be received from the network/PCF, or pre-configured in the UE.

One possibility to achieve the configuration to the UE is using policy provisioning procedures.

A method may comprise providing the configuration from a home public land mobile network to the user equipment via a visited public land mobile network.

The configuration may comprise a list of networks for which multiple registrations are supported (e.g, a list of preferred VPLMNs). Equivalent Home PLMNs (EHPLNM) are PLMNs that are treated like the HPLMN. One or more EHPLNMs can be included in an Equivalent HPLMN list. PLMN codes that are present within this list can replace the HPLMN code derived from the International Mobile Subscriber Identity (IMSI) for PLMN selection purposes. This list is stored on a sim card, e.g. an USIM and is known as the EHPLMN list. The EHPLMN list may also contain the HPLMN code derived from the IMSI. If the HPLMN code derived from the IMSI is not present in the EHPLMN list then it shall be treated as a Visited PLMN for PLMN selection purposes The registration request may comprise a registration identifier associated with the request.

For a roaming UE, HPLMN may indicate to the VPLMN if multiple registrations is allowed/not allowed by the HPLMN (e.g. a new indication from H-PCF to V-PCF, or a new feature/indication in the UDM profile registered at the NRF and discovered by the AM F). If the HPLMN allows multiple registrations and the serving PLMN also supports and allows it, then the Serving PLMN configures the UE with the information that multiple registration is allowed/supported. The method is thus applicable where the serving network is for VPLMN rather than HPLMN.

Alternatively, the HPLMN may pre-configure the UE with the indication on whether it allows the UE to use multiple registration in serving PLMNs (and TAls in the serving PLMNs) (whereby the serving PLMN may be the HPLMN or a VPLMN) that broadcast support of multiple registration. In that case, no indication is needed from H-PCF to V-PCF (or from UDM to AM F).

In an example embodiment, a UE is allowed to do multiple registrations in a serving PLMN if the UE is enabled by the HPLMN to do so (UE (pre)configuration by the HPLMN) and the serving PLMN either broadcasts support of multiple registrations to the UE (in the Tracking Area Identity (TAI) where the UE is currently located) or pre-configures the support of multiple registrations to the UE (in the TAI where the UE is currently located).

The UE is thus aware that multiple registration is allowed/not allowed by operator/network The indication may comprise a number of registrations supported at the serving network function. The indication may be provided via a radio access network (e.g., NG-RAN) in a broadcast message e.g., system information blocks (SIBS).

In an example embodiment, the Serving Network (PLMN or SNPN) provides an indication to the UE that it is capable of supporting more than one registration, e.g. multiple registration capability flag (and possibly the number of allowed simultaneous registrations).

The serving network may broadcast that it is capable of supporting/allowing multiple registration, in this case the UE would trigger multiple registration only if it gets this broadcast information and if the UE was (pre)configured to use multi-registration.

The serving network thus broadcasts to the UE the support of multiple registration. The UE is aware that the serving network supports multiple registrations before the registration process.

The method may comprise determining based on the received configuration, that the network function node for managing access to the first network supports multiple registrations and, based on the determining, providing at least one registration request to the network function node for managing access to the second network based on the indication that the second network supports multiple registrations.

The at least one registration request may be provided to the second network while the user equipment is registered to the same network or a different network.

That is, UE doesn't wait till it gets the Multiple Registration as a capability from the AM F/network after it starts the registration itself. Instead, the UE learns about this capability, e.g., prior to network (PLMN) selection, during the cell camping phase, while acquiring the SIBs of the cell, and hence the UE can decide if it can/cannot trigger Multiple registrations on that cell, and the UE can decide to select another network (PLMN or SNPN) or cell that supports multiple registrations if available.

For example, at method at a user equipment may comprise determining based on the received configuration, that the network function node for managing access to the first network supports multiple registrations and, based on the determining, determining to select or reselect a serving cell belonging to a second network based on the indication that the second network supports multiple registrations.

The AMF may provide this information to the gNB as part of NG Setup. This can apply for a given TA/PLMN, i.e., network capability information can be configured in the gNB on a per TA/PLMN basis. Alternatively, the gNBs may be locally configured with the information of whether multiple registration is supported in the serving PLMN.

This may be useful in the case that the support of multi-registration is not done homogenously in the entire PLMN, e.g. by not all AMFs of the PLMN. In that case the broadcast/indication to the UE may be helpful regardless of what is configured in the UE, e.g. UE could be configured with "multi registration allowed" but would be able to do multiple registration only when being served by an AMF supporting multi-registration.

If the cell broadcasts that it doesn't support multiple registration, the UE may further search for and select another cell that broadcast its support for multiple registrations.

Both cell reselection (idle mode) and handover (connected mode) may be impacted by this proposal, e.g.., in order to find a target cell that also supports/broadcasts the Multiple Registration when the UE has been camping on a cell that supports the multiple registrations.

In an example embodiment, if the UE is configured/preconfigured that multiple registration is allowed, the UE selects a network that broadcasts multiple registration capability, camps in the network and provided registration IDs as part of each registration.

If the UE cannot find a network that broadcasts multiple registration capability, the UE camps in the network for single registration only. The UE does not perform registrations multiple times.

Figure 7 shows a signalling diagram for a implementing an embodiment such as that described with reference to Figures 4 to 6. In this case, the first network is a HPLMN and the second network is a serving network.

In step 1, the UE is configured/pre-configured by HPLMN that multiple registration is allowed for EHPLMN5 and preferred roaming partners (VPLM Ns). This may be a pre-configuration that exists on the USIM or non-volatile memory of the UE (e.g., as a Mobile object (MO)), or it may be a configuration that is received from the HPLMN network, e.g. the UDM, the PCF, to the U E. In step 2, the AMF indicates to NG-RAN that multiple registration is supported.

In step 3, the NG-RAN broadcasts its support of dual or multiple registrations (and optionally, the number of allowed registrations).

In step 4, the UE determines whether multiple registration is allowed and supported in the serving PLMN.

In step 5, the UE may reselect a serving PLMN that supports multiple registrations.

In step 6, the UE triggers multiple registrations with the AMF.

Multiple registration capability in a UE and a network may be needed for various use cases e.g. camp in two 5GS to obtain services from different network slices, camp in two 5GS (PLMN & SNPN) to obtain different services such as voice and data connectivity, camp in 5GS via NTN and TN for different services. Network behaviour can otherwise become unpredictable (and may also result in failure due to network canceling wrong registration), as explained in the problem statement. Also, the UE may not know if it is allowed to trigger multiple registration or not; also it wouldn't know whether multiple registration will work or not in a given network.

The methods described above with reference to Figures 4 to 7 may provide multiple registration support in 5G-Advanced and 6G Systems, and may become critical as part of initial release as 6G is expected to support above mentioned deployment scenarios.

An apparatus may comprise at least one of the following: means for receiving, by a user equipment supporting multiple registrations with one or more networks, a configuration including information that a network function node for managing access to a first network supports multiple registrations or means for obtaining, by the user equipment, an indication from a second network that multiple registrations are supported by a network function node for managing access to the second network and means for providing multiple registration identifiers to the serving network function from the user equipment.

The apparatus may comprise a user equipment as described with reference to Figure 2. The apparatus may comprise the user equipment, such as a mobile phone, be the user equipment or be comprised in the user equipment or a chipset for performing at least some actions of/for the user equipment.

An apparatus may comprise means for providing an indication from a second network to a user equipment capable of multiple registrations with one or more networks that multiple registrations are supported by a network function node for managing access to the second network and means for receiving and accepting multiple registration requests from the user equipment at the second network.

The apparatus may comprise a control apparatus as described with reference to Figure 3. The apparatus may comprise the control apparatus, be the control apparatus or be comprised in the control apparatus or a chipset for performing at least some actions of/for the control apparatus.

An apparatus may comprise means for providing a configuration to a user equipment capable of multiple registrations, the configuration including information that a network function node for managing access to a first network supports multiple registrations.

It should be understood that the apparatuses may comprise or be coupled to other units or modules etc., such as radio parts or radio heads, used in or for transmission and/or reception. Although the apparatuses have been described as one entity, different modules and memory may be implemented in one or more physical or logical entities.

It is noted that whilst some embodiments have been described in relation to 5G networks, similar principles can be applied in relation to other networks and communication systems such as 6G networks or 5G-Advanced networks. Therefore, although certain embodiments were described above by way of example with reference to certain example architectures for wireless networks, technologies and standards, embodiments may be applied to any other suitable forms of communication systems than those illustrated and described herein.

It is also noted herein that while the above describes example embodiments, there are several variations and modifications which may be made to the disclosed solution without departing from the scope of the present invention.

As used herein, "at least one of the following: <a list of two or more elements>" and "at least one of <a list of two or more elements>" and similar wording, where the list of two or more elements are joined 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 the elements.

In general, the various embodiments may be implemented in hardware or special purpose circuitry, software, logic or any combination thereof. Some aspects of the disclosure 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, although the disclosure is not limited thereto. While various aspects of the disclosure may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof As used in this application, the term "circuitry" may refer to one or more or all of the following: (a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and (b) combinations of hardware circuits and software, such as (as applicable): (i) a combination of analog and/or digital hardware circuit(s) with software/firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and I hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation." This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

The embodiments of this disclosure may be implemented by computer software executable by a data processor of the mobile device, such as in the processor entity, or by hardware, or by a combination of software and hardware. Computer software or program, also called program product, including software routines, applets and/or macros, may be stored in any apparatus-readable data storage medium and they comprise program instructions to perform particular tasks. A computer program product may comprise one or more computer-executable components which, when the program is run, are configured to carry out embodiments. The one or more computer-executable components may be at least one software code or portions of it.

Further in this regard it should be noted that any blocks of the logic flow as in the Figures may represent program steps, or interconnected logic circuits, blocks and functions, or a combination of program steps and logic circuits, blocks and functions. The software may be stored on such physical media as memory chips, or memory blocks implemented within the processor, magnetic media such as hard disk or floppy disks, and optical media such as for example DVD and the data variants thereof, CD. The physical media is a non-transitory media.

The term "non-transitory," as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM vs. ROM).

The memory may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The data processors may be of any type suitable to the local technical environment, and may comprise one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASIC), FPGA, gate level circuits and processors based on multi core processor architecture, as non-limiting examples.

Embodiments of the disclosure may be practiced in various components such as integrated circuit modules. The design of integrated circuits is by and large a highly automated process.

Complex and powerful software tools are available for converting a logic level design into a semiconductor circuit design ready to be etched and formed on a semiconductor substrate.

The scope of protection sought for various embodiments of the disclosure is set out by the independent claims. The embodiments and features, if any, described in this specification that do not fall under the scope of the independent claims are to be interpreted as examples useful for understanding various embodiments of the disclosure.

The foregoing description has provided by way of non-limiting examples a full and informative description of the exemplary embodiment of this disclosure. However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings and the appended claims. However, all such and similar modifications of the teachings of this disclosure will still fall within the scope of this invention as defined in the appended claims. Indeed, there is a further embodiment comprising a combination of one or more embodiments with any of the other embodiments previously discussed.

Claims

Claims 1. An apparatus comprising at least one of the following: means for receiving, by a user equipment supporting multiple registrations with one or more networks, a configuration including information that a network function node for managing access to a first network supports multiple registrations or means for obtaining, by the user equipment, an indication from a second network that multiple registrations are supported by a network function node for managing access to the second network; and means for determining, by the user equipment, whether to provide a registration request to the network function node for managing access to the second network based on at least one of the obtained indication or on the received configuration.
2. The apparatus according to claim 1, wherein the indication includes the number of registrations supported by the second network.
3. The apparatus according to claim 1 or claim 2, wherein the apparatus is pre-configured with the information that the network access node for managing access to the first network is capable of supporting multiple registrations or comprises means for receiving the configuration from a home public land mobile network, a visited public land mobile network or a stand-alone non-public network.
4. The apparatus according to any of claims 1 to 3, comprising means for receiving the indication in a broadcast message in cells of the second network.
5. The apparatus according to any of claims 1 to 4, comprising means for determining based on the received configuration, that the network function node for managing access to the first network supports multiple registrations; and based on the determining, means for providing at least one registration request to the network function node for managing access to the second network based on the indication that the second network supports multiple registrations.
6. The apparatus according to claim 5, comprising means for providing the at least one registration request to the second network while the user equipment is registered to the same network or a different network.
7. The apparatus according to any of claims 1 to 6, comprising means for determining based on the received configuration, that the network function node for managing access to the first network supports multiple registrations; and based on the determining, means for determining to select or reselect a serving cell belonging to the second network based on the indication that the second network supports multiple registrations.
8. The apparatus according to any of claims 1 to 7, wherein the configuration comprises a list of networks for which multiple registrations are supported.
9. The apparatus according to any of claims 1 to 8, wherein the registration request comprises a registration identifier associated with the request.
10. The apparatus according to any of claims 1 to 9, wherein the first network and the second network are the same network or different networks.
11. The apparatus according to any one of claims 1 to 10, wherein the first network comprises a home network and the second network comprises a serving network.
12. An apparatus comprising: means for providing an indication from a second network to a user equipment capable of multiple registrations with one or more networks that multiple registrations are supported by a network function node for managing access to the second network; and means for receiving and accepting multiple registration requests from the user equipment at the second network.
13. The apparatus according to claim 12, comprising means for providing the indication via a radio access network in a broadcast message.
14. An apparatus comprising: means for providing a configuration to a user equipment capable of multiple registrations, the configuration including information that a network function node for managing access to a first network supports multiple registrations.
15. The apparatus according to claim 14, comprising means for providing the configuration to the user equipment from a home public land mobile network via a visited public land mobile network.
16. A method comprising: at least one of the following: receiving, by a user equipment supporting multiple registrations with one or more networks, a configuration including information that a network function node for managing access to a first network supports multiple registrations or obtaining, by the user equipment, an indication from a second network that multiple registrations are supported by a network function node for managing access to the second network; and determining, by the user equipment, whether to provide a registration request to the network function node for managing access to the second network based on at least one of the obtained indication or on the received configuration.
17. A method comprising: providing an indication from a second network to a user equipment capable of multiple registrations with one or more networks that multiple registrations are supported by a network function node for managing access to the second network; and receiving and accepting multiple registration requests from the user equipment at the second network.
18. A method comprising: providing a configuration to a user equipment capable of multiple registrations, the configuration including information that a network function node for managing access to a first network supports multiple registrations.
19. A computer readable medium comprising instructions which, when executed by an apparatus, cause the apparatus to perform at least the following: at least one of the following: receiving, by a user equipment supporting multiple registrations with one or more networks, a configuration including information that a network function node for managing access to a first network supports multiple registrations or obtaining, by the user equipment, an indication from a second network that multiple registrations are supported by a network function node for managing access to the second network; and determining, by the user equipment, whether to provide a registration request to the network function node for managing access to the second network based on at least one of the obtained indication or on the received configuration.
20. A computer readable medium comprising instructions which, when executed by an apparatus, cause the apparatus to perform at least the following: providing an indication from a second network to a user equipment capable of multiple registrations with one or more networks that multiple registrations are supported by a network function node for managing access to the second network; and receiving and accepting multiple registration requests from the user equipment at the second network.
21. A computer readable medium comprising instructions which, when executed by an apparatus, cause the apparatus to perform at least the following: providing a configuration to a user equipment capable of multiple registrations, the configuration including information that a network function node for managing access to a first network supports multiple registrations.
22. 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 at least to: at least one of the following: receive, by a user equipment supporting multiple registrations with one or more networks, a configuration including information that a network function node for managing access to a first network supports multiple registrations or obtain, by the user equipment, an indication from a second network that multiple registrations are supported by a network function node for managing access to the second network; and determine, by the user equipment, whether to provide a registration request to the network function node for managing access to the second network based on at least one of the obtained indication or on the received configuration.
23. 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 at least to: provide an indication from a second network to a user equipment capable of multiple registrations with one or more networks that multiple registrations are supported by a network function node for managing access to the second network; and receive and accept multiple registration requests from the user equipment at the second network.
24. 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 at least to: provide a configuration to a user equipment capable of multiple registrations, the configuration including information that a network function node for managing access to a first network supports multiple registrations.