WO2021064445A1

WO2021064445A1 - Mobile network operator (mno) and internet protocol (ip) multimedia subsystem session (ims) slicing

Info

Publication number: WO2021064445A1
Application number: PCT/IB2019/058314
Authority: WO
Inventors: George Foti
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2019-09-30
Filing date: 2019-09-30
Publication date: 2021-04-08

Abstract

Apparatuses and methods for Mobile Network Operator (MNO) and Internet Protocol (IP) Multimedia Subsystem (IMS) slicing. In one embodiment, a method for a Proxy-Call Session Control Function (P-CSCF node) includes sending a request message for requesting registration of the P-CSCF node in a network resource function (NRF) node, the request message including information indicating a MNO associated with the P-CSCF node. The information indicating the MNO includes at least one of: a MNO identifier; and at least one subscriber permanent identifier (SUPI) associated with the MNO. In another embodiment, a method for a Session Management Function (SMF) node includes discovering a profile of a P-CSCF node, the profile including information indicating a MNO associated with the P-CSCF node.

Description

MOBILE NETWORK OPERATOR (MNO) AND INTERNET PROTOCOL (IP) MULTIMEDIA SUBSYSTEM SESSION (IMS) SLICING

TECHNICAL FIELD

Wireless and network communications and in particular, methods and apparatuses for Mobile Network Operator (MNO) and Internet Protocol (IP) Multimedia Subsystem (IMS) slicing.

BACKGROUND

The IP Multimedia Subsystem (hereinafter “IMS”) enables operators of a Public Land Mobile Network (hereinafter “PLMN”) to provide their subscribers with multimedia services based and built on Internet applications, services and protocols. Different services and applications can be offered on top of IMS.

Support for network slicing in IMS is currently being considered by the 3^rd Generation Partnership Project (3 GPP). One of the applications for IMS slicing is MNO virtualization and where an IMS owned operator network is subdivided for use between MNOs and operator own subscribers, and where dedicated resources can be allocated to a single MNO at the MNO’s request, or shared by more than one MNO. IMS network slicing may hence provide new business models for MNOs and other operators.

FIG. 1 depicts an example how MNOs can make use of IMS network slicing. For example, in FIG. 1, the MNOs are allocated different IMS slices, each of the IMS slices being associated to and/or made up of different IMS resources in a system 10 (e.g., P-CSCF, S-CSCF, etc.) for each MNO. FIG. 1 illustrates that each MNO (MNOl, MN02 and MN03) is associated to and/or uses a respective IMS slice (IMS slice 1, IMS slice 2 and IMS slice 3, respectively), as well as, a respective subscriber database 16 (e.g., Home Location Register (HLR)l 16a, HLR2 16b and HLR3 16c, respectively).

FIG. 2 depicts an example of MNOs sharing resources in a system 10. For example, FIG. 2 shows MN02 and MN03 sharing at least some resources (as indicated by the partial overlapping of IMS slice 2 and IMS slice 3) but also having some dedicated resources for the MNOs. FIG. 3 illustrates yet another example of the MNO usage of IMS slicing in a system 10 including at least IMS resources: P-CSCF1 18a, P-CSCF2 18b, P-CSCF3 18c, P-CSCF4 18d, S-CSCF1 20a, S-CSCF220b, S-CSCF3 20c, S-CSCF420d, S- CSCF5 20e, S-CSCF620f, subscriber database (HLRl)16a, subscriber database (HLR2)16b. For example, FIG. 3 shows MNOl and MN02 being associated to and/or using a respective subscriber database 16 (MNOl HLR1 16a and MN02 HLR2 16b, respectively) and also that MNOl uses P-CSCF1 18a, P-CSCF2 18b (shared with MN02) and S-CSCF1 20a, S-CSCF220b, and S-CSCF3 20c (shared with MN02). MN02 uses P-CSCF2 18b (shared with MNOl), P-CSCF3 18c and S- CSCF3 20c (shared with MNOl), S-CSCF420d, S-CSCF520e, and S-CSCF620f. MNOl uses IMS slice 1, while MN02 uses IMS slice 2, with some resources shared between the MNOs and slices. For example, FIG. 3 shows that P-CSCF2 18b is common to IMS slice 1 and IMS slice 2; and that S-CSCF3 20c is common to IMS slice 1 and IMS slice 2. With IMS network slicing, network resources can be distributed and/or shared to service different use cases (e.g., latency, reliability, capacity and domain specific functionalities).

However, there currently exists some challenges to IMS network slicing. For example, it is not clear how different MNOs can share such resources in existing network architectures.

SUMMARY

Some embodiments advantageously provide methods and apparatuses for Mobile Network Operator (MNO) and Internet Protocol (IP) Multimedia Subsystem (IMS) slicing.

According to one aspect of the present disclosure, a method for a Proxy-Call Session Control Function, P-CSCF, node for an Internet Protocol, IP, Multimedia Subsystem, IMS, is provided. The method includes sending a request message for requesting registration of the P-CSCF node in a network resource function, NRF, node. The request message includes information indicating a mobile network operator, MNO, associated with the P-CSCF node. The information indicating the MNO includes at least one of: a MNO identifier; and at least one subscriber permanent identifier, SUPI, associated with the MNO. In some embodiments of this aspect, the request message is a Nnrf_NFManagement_NFRegister request message. In some embodiments of this aspect, the information indicating the MNO is included in a profile of the P-CSCF node, the profile being stored at the NRF node as part of registration of the P-CSCF node in the NRF node. In some embodiments of this aspect, the profile of the P- CSCF node includes information indicating at least two MNOs sharing the P-CSCF node. In some embodiments of this aspect, the association of the MNO with the P- CSCF node is at least one of: a leasee; and an owner of the P-CSCF node. In some embodiments of this aspect, the method further includes sending a registration message to register a user equipment, UE, with an Internet Protocol, IP, Multimedia Subsystem, IMS, network, the registration message including the information indicating the MNO associated with the P-CSCF node. In some embodiments of this aspect, the method further includes obtaining an IMS network slice identifier associated with the MNO; and sending a registration message to register a user equipment, UE, with an IMS network, the registration message including the IMS network slice identifier corresponding to the MNO associated with the P-CSCF node. In some embodiments of this aspect, the IMS network slice identifier is pre configured in the P-CSCF node. In some embodiments of this aspect, the IMS network slice identifier identifies an IMS network slice, the IMS network slice using at least the P-CSCF node as an IMS network resource.

According to another aspect of the present disclosure, a method for a Session Management Function, SMF, node is provided. The method includes discovering a profile of a Proxy-Call Session Control Function, P-CSCF, node. The profile includes information indicating a mobile network operator, MNO, associated with the P-CSCF node. The information indicating the MNO includes at least one of: a MNO identifier; and at least one subscriber permanent identifier, SUPI, associated with the MNO.

In some embodiments of this aspect, the profile of the P-CSCF node includes information indicating at least two MNOs sharing use of the P-CSCF node as an Internet Protocol, IP, Multimedia Subsystem, IMS, network resource. In some embodiments of this aspect, the method further includes receiving a request message for creating a session management context for an IMS packet data unit, PDU, session for a user equipment, UE, the request message including information indicating an MNO associated with the IMS PDU session. In some embodiments of this aspect, the method further includes obtaining MNO subscription information associated with the UE and comparing the obtained MNO subscription information to the information indicating the MNO in the received request message. In some embodiments of this aspect, the method further includes, as a result of receiving the request message to create the session management context for the IMS PDU session for the UE, using the information indicating the MNO in the received request message to identify the P- CSCF node having the profile associated to the MNO indicated in the received request message. In some embodiments of this aspect, the request message includes one of a Nsmf_PDUSession_CreateSMContext request message and a Nsmf_PDUSession_Create request message. In some embodiments of this aspect, the request message includes a protocol configuration options, PCO, message, the PCO message including the information indicating the MNO.

According to yet another aspect of the present disclosure, a Proxy-Call Session Control Function, P-CSCF, node for an Internet Protocol, IP, Multimedia Subsystem, IMS is provided. The P-CSCF node includes processing circuitry. The processing circuitry is configured to send a request message for requesting registration of the P- CSCF node in a network resource function, NRF, node the request message including information indicating a mobile network operator, MNO, associated with the P-CSCF node. The information indicating the MNO includes at least one of: a MNO identifier; and at least one subscriber permanent identifier, SUPI, associated with the MNO.

In some embodiments of this aspect, the request message is a Nnrf_NFManagement_NFRegister request message. In some embodiments of this aspect, the information indicating the MNO is included in a profile of the P-CSCF node. The profile is stored at the NRF node as part of registration of the P-CSCF node in the NRF node. In some embodiments of this aspect, the profile of the P- CSCF node includes information indicating at least two MNOs sharing the P-CSCF node. In some embodiments of this aspect, the association of the MNO with the P- CSCF node is at least one of: a leasee; and an owner of the P-CSCF node. In some embodiments of this aspect, the processing circuitry is further configured to send a registration message to register a user equipment, UE, with an Internet Protocol, IP, Multimedia Subsystem, IMS, network. The registration message includes the information indicating the MNO associated with the P-CSCF node. In some embodiments of this aspect, the processing circuitry is further configured to obtain an IMS network slice identifier associated with the MNO. In some embodiments of this aspect, the processing circuitry is further configured to send a registration message to register a user equipment, UE, with an IMS network. The registration message includes the IMS network slice identifier corresponding to the MNO associated with the P-CSCF node. In some embodiments of this aspect, the IMS network slice identifier is pre-configured in the P-CSCF node. In some embodiments of this aspect, the IMS network slice identifier identifies an IMS network slice. The IMS network slice uses at least the P-CSCF node as an IMS network resource.

According yet another aspect of the present disclosure, a Session Management Function, SMF, node is provided. The SMF node includes processing circuitry. The processing circuitry is configured to discover a profile of a Proxy-Call Session Control Function, P-CSCF, node. The profile includes information indicating a mobile network operator, MNO, associated with the P-CSCF node. The information indicating the MNO includes at least one of: a MNO identifier; and at least one subscriber permanent identifier, SUPI, associated with the MNO.

In some embodiments of this aspect, the profile of the P-CSCF node includes information indicating at least two MNOs sharing use of the P-CSCF node as an Internet Protocol, IP, Multimedia Subsystem, IMS, network resource. In some embodiments of this aspect, the processing circuitry is further configured to receive a request message for creating a session management context for an IMS packet data unit, PDU, session for a user equipment, UE. The request message includes information indicating an MNO associated with the IMS PDU session. In some embodiments of this aspect, the processing circuitry is further configured to obtain MNO subscription information associated with the UE and comparing the obtained MNO subscription information to the information indicating the MNO in the received request message. In some embodiments of this aspect, the processing circuitry is further configured to, as a result of receiving the request message to create the session management context for the IMS PDU session for the UE, use the information indicating the MNO in the received request message to identify the P-CSCF node having the profile associated to the MNO indicated in the received request message.

In some embodiments of this aspect, the request message includes one of a Nsmf_PDUSession_CreateSMContext request message and a

Nsmf_PDUSession_Create request message. In some embodiments of this aspect, the request message includes a protocol configuration options, PCO, message, the PCO message including the information indicating the MNO.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present embodiments, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:

FIG. 1 is a schematic diagram illustrating an example arrangement for how MNOs can make use of IMS network slicing;

FIG. 2 is a schematic diagram illustrating an example arrangement in which two MNOs, MN02 and MN03, share some resources while also having dedicated resources for themselves;

FIG. 3 is a block diagram illustrating yet another example of MNOs using of IMS network slicing;

FIG. 4 is a block diagram illustrating an example system architecture according to some embodiments of the present disclosure;

FIG. 5 illustrates yet another example system architecture and example hardware arrangements for devices in the system, according to some embodiments of the present disclosure;

FIG. 6 is a flowchart of an example process in a P-CSCF node for requestor according to some embodiments of the present disclosure;

FIG. 7 is a flowchart of an example process in a SMF node for discoverer according to some embodiments of the present disclosure;

FIG. 8 is a call flow diagram of an example process in a system for P-CSCF registration in NRF and P-CSCF discovery according to some embodiments of the present disclosure; FIG. 9 is a call flow diagram of another example process in a system related to a UE initiating and/or establishing an IMS PDU session according to some embodiments of the present disclosure; and

FIG. 10 is a call flow diagram of another example process in a system related to a UE registering with IMS according to some embodiments of the present disclosure.

DETAILED DESCRIPTION

Some embodiments of the present disclosure provide arrangements for how MNOs can share resources (e.g., IMS network slice resources such as, for example, P- CSCF, S-CSCF, HLR, etc.) in an IMS network slicing environment. For example, some embodiments of the present disclosure provide support for MNO resource sharing regardless of the various different sharing scenarios, such as, for example, a separate subscriber database 16 being used by each MNO, one subscriber database being shared by multiple MNOs, or the operator of the IMS-owned subscriber database being used.

Some embodiments of the present disclosure provide arrangements and techniques that facilitate resource sharing, whether e.g., a separate IMS resource is allocated to an MNO, or shared by more than one MNO. Some embodiments of the present disclosure may benefit MNOs. In addition, enterprises desiring to have their own IMS system can benefit from and/or utilize the disclosed arrangements.

Some embodiments of the present disclosure may include one or more of the following:

The 3GPP 5^th Generation (5G) (also called New Radio (NR)) wireless device (WD) or user equipment (UE)) profile includes the MNO (e.g., MNO identifier) that the WD/UE belongs to and/or may be stored part of the Nudm_SubscriberDataManagement (SDM) Service as a new data element similar to other subscription data and/or which the SMF can fetch using the service Nudm_Get service. This can advantageously enable the SMF to validate the MNO if provided by the WD/UE at IMS PDU session establishment and/or enable the SMF to use this information for P-CSCF selection during discovery. The UE at IMS PDU session establishment can include either the UE’s SUPI or the MNO that the UE belongs to in the PCO (or both SUPI and MNO) during IMS PDU session establishment. The UE may be configured with this information apriori in order to include such information during IMS PDU session establishment.

At IMS PDU session establishment, the SMF may retrieve the SUPI and/or MNO identifier from the PCO if available. In addition, the AMF may include the SUPI when the AMF forwards the IMS PDU session establishment to the SMF. This may enable the SMF to validate the UE- included SUPI if provided. The SMF may also retrieve the MNO subscription data type and validate the MNO subscription data type against the UE-included MNO identifier if provided in the PCO. This can make the use of the PCO optional both for the SUPI and MNO identifier. The SMF may use the SUPFMNO identifier to locate the P-CSCFs that can handle this UE and session (see below for what the P-CSCF registers in the NRF for discovery).

The P-CSCF may, at registration of its profile in the NRF, include the MNO identifier(s) of the MNO(s) that the P-CSCF is to be allocated for at IMS PDU session establishment if the UE provides an MNO identifier.

The P-CSCF may also include, as part of its profile, the SUPI range of the UE(s) for which the P-CSCF may be allocated for at IMS PDU session establishment.

The SMF may discover the P-CSCF profile and store all the additional information so that the SMF can use the information later during IMS PDU session establishment in order to return to the UE the applicable list of P-CSCFs.

For IMS, some embodiments of the present disclosure may include one or more of the following additional elements:

P-CSCFs may be configured with the MNO identifier(s) associated to the MNO(s) that the P-CSCFs are used for and/or an IMS network slice identifier corresponding to the P-CSCF and/or MNO. Information provisioned in the subscriber databasel6 (e.g., HLR/HSS/UDM) regarding services supported by a S-CSCF may now also include the MNO identifier(s) of the MNO(s) the S-CSCF is allocated for.

In response to e.g., a query including one or more of the MNO identifier(s) of the MNO(s) to which the S-CSCF(s) can be allocated, the subscriber databasel6 (e.g., HLR/HSS/UDM) may return, to an Interrogating-Call Session Control Function (I-CSCF), only the S-CSCF(s) that can be allocated to the MNO(s) based on provisioned information, where applicable.

At IMS registration, the P-CSCF may include in the outgoing IMS Session Initiation Protocol (SIP) Register Request the MNO(s) and/or the corresponding IMS network slice identity. I-CSCF may use this information in its query to locate in subscriber databasel6 (e.g., HLR/HSS/UDM) S-CSCF(s) that can be allocated to the UE and/or the MNO.

Some embodiments of the present disclose may advantageously propose techniques that allow IMS network slicing to provide a flexible arrangement to support MNOs and/or private enterprises in an efficient manner, and with relatively minor changes to existing networks and existing messaging in e.g., network function (NF) registration and discovery, IMS PDU session establishment and IMS registration.

Note that while the description of the various embodiments in the present disclose primarily discusses the techniques in terms of MNOs, it should be understood that the techniques disclosed herein can also be used by any enterprise that desires to have their own private virtual IMS network.

Before describing in detail exemplary embodiments, it is noted that the embodiments reside primarily in combinations of apparatus components and processing steps related to Mobile Network Operator (MNO) and Internet Protocol (IP) Multimedia Subsystem (IMS) slicing. Accordingly, components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

As used herein, relational terms, such as “first” and “second,” “top” and “bottom,” and the like, may be used solely to distinguish one entity or element from another entity or element without necessarily requiring or implying any physical or logical relationship or order between such entities or elements. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the concepts described herein. 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. It will be further understood that the terms “comprises,” “comprising,” “includes” and/or “including” when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

In embodiments described herein, the joining term, “in communication with” and the like, may be used to indicate electrical or data communication, which may be accomplished by physical contact, induction, electromagnetic radiation, radio signaling, infrared signaling or optical signaling, for example. One having ordinary skill in the art will appreciate that multiple components may interoperate and modifications and variations are possible of achieving the electrical and data communication.

In some embodiments described herein, the term “coupled,” “connected,” and the like, may be used herein to indicate a connection, although not necessarily directly, and may include wired and/or wireless connections.

In some embodiments, the non-limiting terms wireless device (WD) or a user equipment (UE) are used interchangeably. The UE herein can be any type of wireless device capable of communicating with a network node or another UE over radio signals. The UE herein can by any type of communication device capable of communicating with another UE, an application server, a network node, a server, an IMS NF or other IMS network node, via a wired connection and/or a wireless connection. The UE may also be a radio communication device, target device, device to device (D2D) UE, machine type UE or UE capable of machine to machine communication (M2M), low-cost and/or low-complexity UE, a sensor equipped with UE, Tablet, mobile terminals, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles, Customer Premises Equipment (CPE), an Internet of Things (IoT) device, or a Narrowband IoT (NB-IOT) device etc.

In some embodiments, the term “node” and “network node” is used interchangeably herein and can be any kind of network node, such as, a subscriber database node and a Network Function (NF) node, such as a P-CSCF node, S-CSCF node, I-CSCF node, AMF node, SMF node, NRF node, etc. As used herein, the terms P-CSCF node, S-CSCF node, I-CSCF node, AMF node, SMF node and NRF node may be used interchangeably with the terms P-CSCF, S-CSCF, I-CSCF, AMF, SMF and NRF, respectively.

A node may include physical components, such as processors, allocated processing elements, or other computing hardware, computer memory, communication interfaces, and other supporting computing hardware. The node may use dedicated physical components, or the node may be allocated use of the physical components of another device, such as a computing device or resources of a datacenter, in which case the node is said to be virtualized. A node may be associated with multiple physical components that may be located either in one location, or may be distributed across multiple locations.

One or more of the nodes described herein may support IMS network slicing according to some embodiments of the present disclosure.

A network slice generally corresponds to a set of network resources which have been allocated to support at least one specific service on the network. Such network resources may include cloud-based communication resources, computing and memory resources, physical connection and communication resources, wireless radio access resources such as frequency, time and code multi-access resources, telecommunication resources, memory resources and computing resources. A user equipment (UE) seeking access to a service may connect to a network slice that supports the service.

In some embodiments, the terms “predefined/predetermined” and “pre configured” in the context of this disclosure may refer to the related information being defined for example in a standard, and/or being available without being received from a node, e.g. stored in memory, for example independent of receiving information from the network.

In some embodiments, the term “obtain” or “obtaining” is used herein and may indicate obtaining in e.g., memory such as in the case where the information is predefined or pre-configured. The term “obtain” or “obtaining” as used herein may also indicate obtaining by receiving signaling indicating the information obtained.

In some embodiments, the term “protocol configuration option (PCO)” is used and may in some embodiments encompass extended PCO (ePCO), as well.

Any two or more embodiments described in this disclosure may be combined in any way with each other.

Note also that some embodiments of the present disclosure may be supported by standard documents disclosed in Third Generation Partnership Project (3GPP) technical specifications. That is, some embodiments of the description can be supported by the above documents. In addition, all the terms disclosed in the present document may be described by the above standard documents.

Note that although terminology from one particular wireless system, such as, for example, 3^rd Generation Partnership Project (3GPP), Long Term Evolution (LTE), 5^th Generation (5G) and/or New Radio (NR), may be used in this disclosure for clarity, this should not be seen as limiting the scope of the disclosure to only the aforementioned system. Other wireless systems, including without limitation Wide Band Code Division Multiple Access (WCDMA), Worldwide Interoperability for Microwave Access (WiMax), Ultra Mobile Broadband (UMB) and Global System for Mobile Communications (GSM), may also benefit from exploiting the ideas covered within this disclosure.

Note further, that functions described herein as being performed by a UE, subscriber databasel6, a P-CSCF node 18, S-CSCF node 20 or any network node (e.g., AMF, NRF, I-CSCF, etc.) may be distributed over a plurality of UEs, a plurality of subscriber databases 16, a plurality of P-CSCF nodes 18, a plurality of S-CSCF nodes 20 and/or a plurality of network nodes. In other words, it is contemplated that the functions of the UE, subscriber databasel6, P-CSCF node 18, S-CSCF node 20 and any network node described herein are not limited to performance by a single physical device and, in fact, can be distributed among several physical devices. Unless otherwise expressly defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Referring again to the drawing figures, in which like elements are referred to by like reference numerals, there is shown in FIG. 4 a schematic diagram of another example communication system 10, according to some embodiments, constructed in accordance with the principles of the present disclosure. The communication system 10 in FIG. 4 is a non-limiting example and other embodiments of the present disclosure may be implemented by one or more other systems and/or networks. Referring to FIG. 4, system 10 includes UE 22, in addition to various support elements for supporting IMS communications, such as, a radio access network (RAN) 24 (e.g., 4G, 5G or NR RAN, etc.), which may provide radio access to the UE 22, and a subscriber databasel6 (e.g., Home Location Register/Home Subscriber Server/User Data Management (HLR/HSS/UDM)), which may provide a database of subscriber information allowing users to be granted access to the IMS associated with the subscriber’s specific information. The system 10 includes an Access and Mobility Management Function (AMF) node 26, which may provide a function for access and mobility management for the UE 22, and a Session Management Function (SMF) node 28, which may provide session management for the UE 22. The system 10 may further include the Proxy-Call Session Control Function (P-CSCF) node 18, which may provide proxy communications between the UE 22 and the IMS via e.g., the RAN 24. The system 10 further includes a Network Function (NF) Repository Function (NRF) node 30, which may provide support for NF service registration and discovery, enabling NFs to identify appropriate services in one another. The system 10 further includes Serving-Call Session Control Function (S-CSCF) node 20, which may be an IMS entity assigned to the UE 22 e.g., during IMS registration, and an Interrogating-Call Session Control Function (I-CSCF) node 32. It should be noted that, for simplicity, a single node is shown for the various entities in the system 10 depicted in FIG. 4 (e.g., a single UE 22, a single P-CSCF node 18 and a single S- CSCF node 20, etc.); however, it should be understood that the system 10 may include numerous entities/nodes of those shown in FIG. 4, as well as, additional entities/nodes not shown in FIG. 4. In addition, the system 10 may include many more connections than those shown in FIG. 4.

Example implementations, in accordance with an embodiment, of the UE 22, P-CSCF node 18, SMF node 28 and a network node 34 (which may be any network node or any node supporting IMS, such as, for example, AMF node 26, S-CSCF node 20, 1-CSCF node 32, NRF node 30, subscriber databasel6, etc.) discussed herein will now be described with reference to FIG. 5.

The UE 22 includes a communication interface 40, processing circuitry 42, and memory 44. The communication interface 40 may be configured to communicate with the P-CSCF node 18 and/or other elements in the system 10 to facilitate MNO use of IMS slicing according to one or more embodiments of the present disclosure.

In some embodiments, the communication interface 40 may be formed as or may include, for example, one or more radio frequency (RF) transmitters, one or more RF receivers, and/or one or more RF transceivers, and/or may be considered a radio interface. In some embodiments, the communication interface 40 may also include a wired interface.

The processing circuitry 42 may include one or more processors 46 and memory, such as, the memory 44. In particular, in addition to a traditional processor and memory, the processing circuitry 42 may comprise integrated circuitry for processing and/or control, e.g., one or more processors and/or processor cores and/or FPGAs (Field Programmable Gate Array) and/or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 46 may be configured to access (e.g., write to and/or read from) the memory 44, which may comprise any kind of volatile and/or nonvolatile memory, e.g., cache and/or buffer memory and/or RAM (Random Access Memory) and/or ROM (Read-Only Memory) and/or optical memory and/or EPROM (Erasable Programmable Read-Only Memory).

Thus, the UE 22 may further include software stored internally in, for example, memory 44, or stored in external memory (e.g., database) accessible by the UE 22 via an external connection. The software may be executable by the processing circuitry 42. The processing circuitry 42 may be configured to control any of the methods and/or processes described herein and/or to cause such methods, and/or processes to be performed, e.g., by the UE 22. The memory 44 is configured to store data, programmatic software code and/or other information described herein. In some embodiments, the software may include instructions stored in memory 44 that, when executed by the processor 46, causes the processing circuitry 42 and/or configures the UE 22 to perform the processes described herein with respect to the UE 22.

The P-CSCF node 18 includes a communication interface 50, processing circuitry 52, and memory 54. The communication interface 50 may be configured to communicate with the UE 22 and/or other elements in the system 10 to facilitate MNO use of IMS slicing according to one or more embodiments of the present disclosure. In some embodiments, the communication interface 50 may be formed as or may include, for example, one or more radio frequency (RF) transmitters, one or more RF receivers, and/or one or more RF transceivers, and/or may be considered a radio interface. In some embodiments, the communication interface 50 may also include a wired interface.

The processing circuitry 52 may include one or more processors 56 and memory, such as, the memory 54. In particular, in addition to a traditional processor and memory, the processing circuitry 52 may comprise integrated circuitry for processing and/or control, e.g., one or more processors and/or processor cores and/or FPGAs (Field Programmable Gate Array) and/or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 56 may be configured to access (e.g., write to and/or read from) the memory 54, which may comprise any kind of volatile and/or nonvolatile memory, e.g., cache and/or buffer memory and/or RAM (Random Access Memory) and/or ROM (Read-Only Memory) and/or optical memory and/or EPROM (Erasable Programmable Read-Only Memory).

Thus, the P-CSCF node 18 may further include software stored internally in, for example, memory 54, or stored in external memory (e.g., database) accessible by the P-CSCF node 18 via an external connection. The software may be executable by the processing circuitry 52. The processing circuitry 52 may be configured to control any of the methods and/or processes described herein and/or to cause such methods, and/or processes to be performed, e.g., by the P-CSCF node 18. The memory 54 is configured to store data, programmatic software code and/or other information described herein. In some embodiments, the software may include instructions stored in memory 54 that, when executed by the processor 56 and/or requester 58, causes the processing circuitry 52 and/or configures the P-CSCF node 18 to perform the processes described herein with respect to the P-CSCF node 18 (e.g., processes described with reference to FIG. 6 and/or any of the other flowcharts and figures).

The SMF node 28 includes a communication interface 60, processing circuitry 62, and memory 64. The communication interface 60 may be configured to communicate with the P-CSCF node 18 and/or other elements in the system 10 to facilitate MNO use of IMS slicing according to one or more embodiments of the present disclosure. In some embodiments, the communication interface 60 may be formed as or may include, for example, one or more radio frequency (RF) transmitters, one or more RF receivers, and/or one or more RF transceivers, and/or may be considered a radio interface. In some embodiments, the communication interface 60 may also include a wired interface.

The processing circuitry 62 may include one or more processors 66 and memory, such as, the memory 64. In particular, in addition to a traditional processor and memory, the processing circuitry 62 may comprise integrated circuitry for processing and/or control, e.g., one or more processors and/or processor cores and/or FPGAs (Field Programmable Gate Array) and/or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 66 may be configured to access (e.g., write to and/or read from) the memory 64, which may comprise any kind of volatile and/or nonvolatile memory, e.g., cache and/or buffer memory and/or RAM (Random Access Memory) and/or ROM (Read-Only Memory) and/or optical memory and/or EPROM (Erasable Programmable Read-Only Memory).

Thus, the SMF node 28 may further include software stored internally in, for example, memory 64, or stored in external memory (e.g., database) accessible by the SMF node 28 via an external connection. The software may be executable by the processing circuitry 62. The processing circuitry 62 may be configured to control any of the methods and/or processes described herein and/or to cause such methods, and/or processes to be performed, e.g., by the SMF node 28. The memory 64 is configured to store data, programmatic software code and/or other information described herein. In some embodiments, the software may include instructions stored in memory 64 that, when executed by the processor 66 and/or discoverer 68, causes the processing circuitry 62 and/or configures the SMF node 28 to perform the processes described herein with respect to the SMF node 28 (e.g., processes described with reference to FIG. 7 and/or any of the other flowcharts and figures).

The network node 34 includes a communication interface 70, processing circuitry 72, and memory 74. The communication interface 70 may be configured to communicate with the UE 22 and/or other elements in the system 10 to facilitate MNO use of IMS slicing according to one or more embodiments of the present disclosure. In some embodiments, the communication interface 70 may be formed as or may include, for example, one or more radio frequency (RF) transmitters, one or more RF receivers, and/or one or more RF transceivers, and/or may be considered a radio interface. In some embodiments, the communication interface 70 may also include a wired interface.

The processing circuitry 72 may include one or more processors 76 and memory, such as, the memory 74. In particular, in addition to a traditional processor and memory, the processing circuitry 72 may comprise integrated circuitry for processing and/or control, e.g., one or more processors and/or processor cores and/or FPGAs (Field Programmable Gate Array) and/or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 76 may be configured to access (e.g., write to and/or read from) the memory 74, which may comprise any kind of volatile and/or nonvolatile memory, e.g., cache and/or buffer memory and/or RAM (Random Access Memory) and/or ROM (Read-Only Memory) and/or optical memory and/or EPROM (Erasable Programmable Read-Only Memory).

Thus, the network node 34 may further include software stored internally in, for example, memory 74, or stored in external memory (e.g., database) accessible by the network node 34 via an external connection. The software may be executable by the processing circuitry 72. The processing circuitry 72 may be configured to control any of the methods and/or processes described herein and/or to cause such methods, and/or processes to be performed, e.g., by the network node 34. The memory 74 is configured to store data, programmatic software code and/or other information described herein. In some embodiments, the software may include instructions stored in memory 74 that, when executed by the processor 76, causes the processing circuitry 72 and/or configures the network node 34 to perform the processes described herein with respect to the network node 34.

In FIG. 5, the connection between the devices UE 22, P-CSCF node 18, SMF node 28 and an network node 34 (which may be any network node or any node supporting IMS, such as, for example, AMF node 26, S-CSCF node 20, 1-CSCF node 32, NRF node 30, subscriber databasel6, etc.) is shown without explicit reference to any intermediary devices or connections. However, it should be understood that intermediary devices and/or connections may exist between these devices, although not explicitly shown.

Although FIG. 5 shows requester 58 and discoverer 68, as being within a respective processor, it is contemplated that these elements may be implemented such that a portion of the elements is stored in a corresponding memory within the processing circuitry. In other words, the elements may be implemented in hardware or in a combination of hardware and software within the processing circuitry.

FIG. 6 is a flowchart of an exemplary process in a P-CSCF node 18 for facilitating MNO use of IMS slicing according to one or more embodiments of the present disclosure. One or more Blocks and/or functions and/or methods performed by the P-CSCF node 18 may be performed by one or more elements of P-CSCF node 18 such as by requester 58 in processing circuitry 52, memory 54, processor 56, communication interface 50, etc. according to the example process/method. The example process includes sending (Block S100), such as via requester 58, processing circuitry 52, memory 54, processor 56 and/or communication interface 50, a request message for requesting registration of the P-CSCF node 18 in a network resource function, NRF, node. The request message includes information indicating a mobile network operator, MNO, associated with the P-CSCF node 18. The information indicating the MNO includes at least one of: a MNO identifier; and at least one subscriber permanent identifier, SUPI, associated with the MNO. In some embodiments, the request message is a Nnrf_NFManagement_NFRegister request message. In some embodiments, the information indicating the MNO is included in a profile of the P-CSCF node, the profile being stored at the NRF node as part of registration of the P-CSCF node in the NRF node. In some embodiments, the profile of the P-CSCF node includes information indicating at least two MNOs sharing the P-CSCF node. In some embodiments, the association of the MNO with the P-CSCF node is at least one of: a leasee; and an owner of the P-CSCF node. In some embodiments, the method further includes sending, such as via requester 58, processing circuitry 52, memory 54, processor 56 and/or communication interface 50, a registration message to register a user equipment, UE 22, with an Internet Protocol, IP, Multimedia Subsystem, IMS, network. The registration message includes the information indicating the MNO associated with the P-CSCF node 18. In some embodiments, the method further includes obtaining, such as via requester 58, processing circuitry 52, memory 54, processor 56 and/or communication interface 50, an IMS network slice identifier associated with the MNO. In some embodiments, the method further includes sending, such as via requester 58, processing circuitry 52, memory 54, processor 56 and/or communication interface 50, a registration message to register a user equipment, UE 22, with an IMS network. The registration message includes the IMS network slice identifier corresponding to the MNO associated with the P-CSCF node 18. In some embodiments, the IMS network slice identifier is pre-configured in the P- CSCF node 18. In some embodiments, the IMS network slice identifier identifies an IMS network slice, the IMS network slice using at least the P-CSCF node as an IMS network resource.

FIG. 7 is a flowchart of an exemplary process in a SMF node 28 for facilitating MNO use of IMS slicing according to one or more embodiments of the present disclosure. One or more Blocks and/or functions and/or methods performed by the SMF node 28 may be performed by one or more elements of SMF node 28 such as discoverer 68 in processing circuitry 62, memory 64, processor 66, communication interface 60, etc. according to the example process/method. The example process includes discovering (Block S102), such as via discoverer 68, processing circuitry 62, memory 64, processor 66 and/or communication interface 60, a profile of a Proxy-Call Session Control Function, P-CSCF, node 18, the profile including information indicating a mobile network operator, MNO, associated with the P-CSCF node 18. The information indicating the MNO includes at least one of: a MNO identifier; and at least one subscriber permanent identifier, SUPI, associated with the MNO.

In some embodiments, the profile of the P-CSCF node 18 includes information indicating at least two MNOs sharing use of the P-CSCF node 18 as an Internet Protocol, IP, Multimedia Subsystem, IMS, network resource. In some embodiments, the method further includes receiving, such as via discoverer 68, processing circuitry 62, memory 64, processor 66 and/or communication interface 60, a request message for creating a session management context for an IMS packet data unit, PDU, session for a user equipment, UE, the request message including information indicating an MNO associated with the IMS PDU session. In some embodiments, the method further includes obtaining, such as via discoverer 68, processing circuitry 62, memory 64, processor 66 and/or communication interface 60, MNO subscription information associated with the UE 22 and comparing the obtained MNO subscription information to the information indicating the MNO in the received request message. In some embodiments, the method further includes, as a result of receiving the request message to create the session management context for the IMS PDU session for the UE 22, using, such as via discoverer 68, processing circuitry 62, memory 64, processor 66 and/or communication interface 60, the information indicating the MNO in the received request message to identify the P-CSCF node 18 having the profile associated to the MNO indicated in the received request message. In some embodiments, the request message includes one of a Nsmf_PDUSession_CreateSMContext request message and a Nsmf_PDUSession_Create request message. In some embodiments, the request message includes a protocol configuration options, PCO, message. The PCO message includes the information indicating the MNO.

Having generally described arrangements for Mobile Network Operator (MNO) and Internet Protocol (IP) Multimedia Subsystem (IMS) slicing, a more detailed description of some of the embodiments are provided as follows with reference to FIGS. 8-10, and which may be implemented by UE 22, P-CSCF node 18, SMF node 28 and a network node 34 (which may be any IMS node or any network node, such as, for example, AMF node 26, S-CSCF node 20, 1-CSCF node 32, NRF node 30, subscriber databasel6, etc.). The call flow diagrams in FIGS. 8-10 show non-limiting example procedures that may be followed by the network according to some embodiments of the present disclosure.

FIG. 8 illustrates an example of UE configuration, P-CSCF registration with NRF and SMF discovery procedures. In some embodiments, these steps may not be performed in the sequence shown. In step S200, the UE 22 is configured with an MNO identifier. In some embodiments, the UE 22 is configured with an MNO identifier identifying the MNO that the UE 22 is associated to and/or a SUPI that is associated to a particular MNO/MNO identifier. Thus, whether an MNO identifier is used, or a SUPI that is associated to a particular MNO (or both), the UE 22 can be associated with a particular MNO in the network. In step S202, the P-CSCF2 18b registers with NRF 30. Included in the P-CSCF2’s 18b profile is one or more MNO identifier(s) associated to P-CSCF2 18b. In some embodiments, the profile includes a SUPI range, the SUPI range being associated with a particular MNO. In step S204, the P-CSCF1 18b registers with NRF 30. Included in the P-CSCFl’s 18a profile is one or more MNO identifier(s) associated to P-CSCF1 18a. In some embodiments, the profile includes a SUPI range, the SUPI range being associated with a particular MNO. Thus, the P-CSCFs’ 18a and 18b registration of their profiles with the NRF 30 includes the new additional information provided in this disclosure (namely, the MNO identifier(s) and/or the SUPI range) that may support MNOs using and/or sharing IMS network slicing resources. In step S206, the SMF 28 discovers the P-CSCFs 18a, 18b and their P-CSCF profiles and stores the profile information. The stored profile information may then be used during IMS PDU establishment/connectivity for a UE 22. One example of use of this new additional profile information at IMS PDU establishment is provided below with reference to the call flow diagram in FIG. 9.

In FIG. 9, a UE 22 initiates an IMS PDU session according to one embodiment of the present disclosure. In step S210, the UE 22 performs a 5G registration, such as defined in e.g., Third Generation Partnership Project (3GPP) Technical Specification (TS) 23.502, section 4.2.2. In step S212, the UE 22 initiates an IMS PDU establishment request to the AMF 26. The UE 22 includes, in the PCO, the MNO identifier identifying the MNO that the UE 22 belongs to (i.e., the MNO identifier configured in the UE 22 in step S200). In some embodiments, the UE 22 may include, in the PCO (or extended PCO), (in addition to the MNO identifier or instead of in some embodiments) the device SUPI which may be associated with the MNO. The PCO may also include neither the SUPI nor the MNO identifier as this information can be obtained from network functions (e.g., the SUPI may be known or determinable by network functions, such as SMF, as a SUPI of a particular MNO, according to e.g., a predetermined/predefined determination procedure). In step S214, as a result of the IMS PDU establishment request, the AMF 26 provides the SUPI to the SMF 28, e.g., when the AMF 26 invokes the, e.g.,

Nsmf_PDUSession_CreateSMContext Request service. The corresponding services for the home routed model may be impacted if such a model is used (Nsmf_PDUSession_Create). For example, the call flow diagram in FIG. 9 may be considered to describe an example of a local breakout (FBO) approach, in case of roaming as well as the case of a non-roaming subscriber. However, some embodiments may also be applicable to a home routed (HR) routing for a roaming subscriber, which in such a case there may be 2 SMFs in this alternative embodiment, one SMF in the visited domain V-SMF, and one SMF in the home domain H-SMF. The SMF in the home domain, H-SMF, may perform the SMF 28 steps described in FIG. 9. However, in the case of FBO (roaming scenario), the V-SMF would perform the SMF 28 steps in FIG. 9. The difference may be in the messages that trigger the SMF 28 to perform the steps (e.g., one of more of steps S216, S220-S224). In the case of FBO, and non-roaming subscribers, it may be a

Nsmf_PDUSession_CreateSMContext request message that triggers the SMF 28, which is shown in FIG. 9. In the home routed scenario, it may be a Nsmf_PDUSession_Create request message that triggers the SMF 28 (not shown in FIG. 9).

In step S216, the SMF 28 intercepts the PCO from the UE 22 and extracts the available information from the PCO (e.g., SUPI associated to MNO, MNO identifier, both or neither if not available). In step S218, the SMF 28 fetches the MNO identifier from the subscriber database 16. In some embodiments, the SMF 28 may fetch the MNO data subscription type as an additional type when the SMF 28 invokes e.g., the Nudm_Get service to fetch the UE 22 profile.

In some embodiments, the SMF 28 may perform an authentication/verification procedure to verify that the additional UE/PCO information, if provided, matches the network provided information. For example, the SMF 28 may compare the SUPI received from the AMF 26 (e.g., via step S214) with the SUPI received in the PCO from the UE 22, if available. Similarly, in some embodiments, the SMF 28 may compare the fetched MNO identifier (e.g., from step S218) identifying the MNO that the UE 22 belongs to with the MNO identifier included in the PCO, if available. If the UE 22 provided information (MNO identifier and/or SUPU in the PCO) does not match the SMF 28 fetched information, the authentication/verification may fail. In some embodiments, local policies may determine whether to enable the session establishment to progress based on the network information, or whether to reject the session establishment request if the information does not match up. Subsequently, and based on the information (e.g., MNO identifier and/or SUPI associated to the MNO) the SMF 28 selects the list of P-CSCFs 18 whose profile matches the information. In step S224, the SMF 28 may return the list of selected P-CSCFs 18 to the AMF 26, which passes the list of selected P-CSCFs 18 to the UE 22. Thus, the P-CSCFs 18 associated with the appropriate MNO can be used for the UE 22 that is also associated with that MNO.

FIG. 10 is a call flow diagram that illustrates an example of IMS registration using the arrangements provided in the present disclosure. In step S230, the UE 22 initiates IMS registration. In step S231, the subscriber database 16 stores the MNO identifier(s) and/or the IMS slice identifier(s) for every S-CSCF 20 that is stored at the subscriber database 16 (this step may occur out of the sequence order shown in the diagram, but is nonetheless shown here to represent that this occurs to support the arrangement shown in FIG. 10 as described in more detail below). In step S232, the P-CSCF 18 obtains an MNO identifier. In some embodiments, the P-CSCF 18 is configured/pre-configured with MNO identifier(s) identifying the MNO(s) that the P- CSCF 18 can be used for. In some other embodiments, the P-CSCF obtains the MNO identifier from the network, such as a network function having this information. As a result of the initiation of the IMS registration, the P-CSCF 18 may also obtain an IMS network slice identifier. In some embodiments, the P-CSCF 18 may obtain the IMS network slice identifier by being configured/pre-configured with the IMS network slice identifier. In some embodiments, the P-CSCF 18 may obtain the IMS network slice identifier from the network, such as a network function having this information. In some embodiments, the IMS network slice identifier may be based at least in part on the MNO identifier. The IMS network slice identifier may be included in the SIP registration message sent from the P-CSCF 18 to other IMS nodes (e.g., step S234, as well as, step S258). Optionally, the MNO identifier may be included in the SIP registration request (e.g., from the UE 22 in step S230).

In step S236, the I-CSCF 32 includes, in a query to the subscriber database 16, the IMS network slice identifier and/or the MNO identifier that the I-CSCF 32 received from the P-CSCF 18. In step S238, the subscriber database 16 (HSS/HLR/UDM) uses this information (the IMS network slice identifier and/or the MNO identifier in the query) to return a list of S-CSCFs 20 that fulfill this query, such as the S-CSCFs 20 that are dedicated for the MNO(s) indicated by the information. Hence, the information provisioned in subscriber database 16 includes, in addition to the list of services supported by the S-CSCFs 20, the MNO identifier(s) that such S- CSCFs 20 can be allocated to. The subscriber database 16 may be provisioned with this information apriori (see step S231).

In step S240, the I-CSCF 32 selects one of the S-CSCFs in the list of S-CSCFs 20 returned from the query. In step S242, the selected S-CSCF 20 receives, from the I-CSCF 32, a registration request message including the IMS network slice identifier and/or the MNO identifier. The S-CSCF 20 may be configured/pre-configured with the MNO identifier(s) and/or the IMS network slice identifier(s) that the S-CSCF 20 can be allocated to. Thus, e.g., in response to the registration request message received in step S242, the S-CSCF 20 can validate this pre-configured information against incoming requests for validation purposes in step S244.

In step S246, the S-CSCF 20 obtains authentication information from the subscriber database 16. In step S248, the subscriber database 16 stores an identifier of the S-CSCF 20 temporarily allocated to the UE 22. In steps S250-S254, the S-CSCF 20 sends a 401 SIP (unauthorized) message towards the UE 22. As a result of receiving the 401 message, the UE 22 sends a registration request message to the P- CSCF 18 in step S256 with the authentication information. In step S258, the P-CSCF 18 sends the registration request message (including the IMS network slice identifier and/or MNO identifier) to the I-CSCF 32. In step S260, responsive to the registration request message including the IMS network slice identifier and/or MNO identifier, the I-CSCF 32 sends a query to the subscriber database 16, the query including the IMS network slice identifier and/or MNO identifier. In step S262, as a result of the query, the subscriber database 16 returns to the I-CSCF 32 the identifier of the S-CSCF 20 allocated to the UE 22 and stored in step 248. In step S264, the I-CSCF 32 sends a registration request message including the IMS network slice identifier and/or MNO identifier to the S-CSCF 20 (e.g., that was identified in step S262). The S-CSCF 20 identifier and/or the associated IMS network slice identifier and/or the associated MNO identifier is stored at the S-CSCF 20 and/or the subscriber database 16 in step S268. In step S270, profile information is obtained. In steps S272-S276, a SIP 200 OK message (indicating a successful registration request) is sent from the S-CSCF 20 towards the UE 22.

In some embodiments, the P-CSCF 18 is shared between two or more MNOs. In this case, the P-CSCF 18 may not know which is the actual MNO that the user/UE 22 belongs to. In such embodiments, the P-CSCF 18 includes in the registration request sent to the I-CSCF 32 (e.g., similar to step S234 in FIG. 10) all the MNOs/IMS slices that share this P-CSCF 18. The I-CSCF 32 may include this information in the query to the subscriber database 16 (e.g., HSS) (e.g., similar to step S236). It is subscriber database 16 (e.g., HSS) then that may know exactly the MNO the registering UE 22 belongs to. This may be provisioned in the subscriber database 16 (e.g., HSS), so that the MNO for the registering UE 22 can be determined. This determined information can be returned in the 200 OK message (e.g., similar to step S274), and the P-CSCF 18 can then store the determined MNO and use the information later, e.g., when the UE 22 refreshes the registration or when the UE 22 is challenged.

In some embodiments, charging information will include the MNO identifier and/or the IMS network slice identifier for proper charging at a charging node. The inclusion of the MNO identifier and/or the IMS network slice identifier can ensure that proper IMS resources/elements are selected for IMS network slices that may be owned and/or leased by one or more MNOs.

It should be understood that although the example embodiments discussed herein may use one or another type of message, the techniques disclosed herein may be used with other types of messages or other communication protocols to support MNO use of IMS network slicing according to the techniques provided in this disclosure.

As will be appreciated by one of skill in the art, the concepts described herein may be embodied as a method, data processing system, and/or computer program product. Accordingly, the concepts described herein may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects all generally referred to herein as a “circuit” or “module.” Furthermore, the disclosure may take the form of a computer program product on a tangible computer usable storage medium having computer program code embodied in the medium that can be executed by a computer. Any suitable tangible computer readable medium may be utilized including hard disks, CD-ROMs, electronic storage devices, optical storage devices, or magnetic storage devices.

Some embodiments are described herein with reference to flowchart illustrations and/or block diagrams of methods, systems and computer program products. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer readable memory or storage medium that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instruction means which implement the function/act specified in the flowchart and/or block diagram block or blocks.

The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

It is to be understood that the functions/acts noted in the blocks may occur out of the order noted in the operational illustrations. For example, two blocks shown in succession may in fact be executed substantially concurrently or the blocks may sometimes be executed in the reverse order, depending upon the functionality/acts involved. Although some of the diagrams include arrows on communication paths to show a primary direction of communication, it is to be understood that communication may occur in the opposite direction to the depicted arrows.

Computer program code for carrying out operations of the concepts described herein may be written in an object oriented programming language such as Java® or C++. However, the computer program code for carrying out operations of the disclosure may also be written in conventional procedural programming languages, such as the "C" programming language. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer. In the latter scenario, the remote computer may be connected to the user's computer through a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).

Many different embodiments have been disclosed herein, in connection with the above description and the drawings. It will be understood that it would be unduly repetitious and obfuscating to literally describe and illustrate every combination and subcombination of these embodiments. Accordingly, all embodiments can be combined in any way and/or combination, and the present specification, including the drawings, shall be construed to constitute a complete written description of all combinations and subcombinations of the embodiments described herein, and of the manner and process of making and using them, and shall support claims to any such combination or subcombination. It will be appreciated by persons skilled in the art that the embodiments described herein are not limited to what has been particularly shown and described herein above. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. A variety of modifications and variations are possible in light of the above teachings without departing from the scope of the following claims.

Claims

What is claimed is:

1. A method for a Proxy-Call Session Control Function, P-CSCF, node (18) for an Internet Protocol, IP, Multimedia Subsystem, IMS, the method comprising: sending (S100) a request message for requesting registration of the P-CSCF node (18) in a network resource function, NRF, node (30), the request message including information indicating a mobile network operator, MNO, associated with the P-CSCF node (18), the information indicating the MNO including at least one of: a MNO identifier; and at least one subscriber permanent identifier, SUPI, associated with the MNO.

2. The method of any one of Claim 1, wherein the request message is a Nnrf_NFManagement_NFRegister request message.

3. The method of any one of Claims 1 and 2, wherein the information indicating the MNO is included in a profile of the P-CSCF node (18), the profile being stored at the NRF node as part of registration of the P-CSCF node (18) in the NRF node (30).

4. The method of Claim 3, wherein the profile of the P-CSCF node (18) includes information indicating at least two MNOs sharing the P-CSCF node (18).

5. The method of any one of Claims 1-4, wherein the association of the MNO with the P-CSCF node (18) is at least one of: a leasee; and an owner of the P-CSCF node (18).

6. The method of any one of Claims 1-5, the method further comprising: sending a registration message to register a user equipment, UE (22), with an

Internet Protocol, IP, Multimedia Subsystem, IMS, network, the registration message including the information indicating the MNO associated with the P-CSCF node (18).

7. The method of any one of Claims 1-6, the method further comprising: obtaining an IMS network slice identifier associated with the MNO; and sending a registration message to register a user equipment, UE (22), with an

IMS network, the registration message including the IMS network slice identifier corresponding to the MNO associated with the P-CSCF node (18).

8. The method of Claim 7, wherein the IMS network slice identifier is pre-configured in the P-CSCF node (18).

9. The method of any one of Claims 7 and 8, wherein the IMS network slice identifier identifies an IMS network slice, the IMS network slice using at least the P-CSCF node (18) as an IMS network resource.

10. A method for a Session Management Function, SMF, node (28), the method comprising: discovering (S102) a profile of a Proxy-Call Session Control Function, P- CSCF, node (18), the profile including information indicating a mobile network operator, MNO, associated with the P-CSCF node (18), the information indicating the MNO including at least one of: a MNO identifier; and at least one subscriber permanent identifier, SUPI, associated with the MNO.

11. The method of Claim 10, wherein the profile of the P-CSCF node (18) includes information indicating at least two MNOs sharing use of the P-CSCF node (18) as an Internet Protocol, IP, Multimedia Subsystem, IMS, network resource.

12. The method of any one of Claims 10 and 11, the method further comprising: receiving a request message for creating a session management context for an IMS packet data unit, PDU, session for a user equipment, UE (22), the request message including information indicating an MNO associated with the IMS PDU session.

13. The method of Claim 12, the method further comprising: obtaining MNO subscription information associated with the UE (22) and comparing the obtained MNO subscription information to the information indicating the MNO in the received request message.

14. The method of any one of Claims 12 and 13, the method further comprising: as a result of receiving the request message to create the session management context for the IMS PDU session for the UE (22), using the information indicating the MNO in the received request message to identify the P-CSCF node (18) having the profile associated to the MNO indicated in the received request message.

15. The method of any one of Claims 12-14, wherein the request message includes one of a Nsmf_PDUSession_CreateSMContext request message and a Nsmf_PDUSession_Create request message.

16. The method of any one of Claims 12-15, wherein the request message includes a protocol configuration options, PCO, message, the PCO message including the information indicating the MNO.

17. A Proxy-Call Session Control Function, P-CSCF, node (18) for an Internet Protocol, IP, Multimedia Subsystem, IMS, the P-CSCF node (18) comprising processing circuitry (52), the processing circuitry (52) configured to: send a request message for requesting registration of the P-CSCF node (18) in a network resource function, NRF, node (30) the request message including information indicating a mobile network operator, MNO, associated with the P-CSCF node (18), the information indicating the MNO including at least one of: a MNO identifier; and at least one subscriber permanent identifier, SUPI, associated with the MNO.

18. The P-CSCF node (18) of any one of Claim 17, wherein the request message is a Nnrf_NFManagement_NFRegister request message.

19. The P-CSCF node (18) of any one of Claims 17 and 18, wherein the information indicating the MNO is included in a profile of the P-CSCF node (18), the profile being stored at the NRF node as part of registration of the P-CSCF node (18) in the NRF node (30).

20. The P-CSCF node (18) of Claim 19, wherein the profile of the P-CSCF node (18) includes information indicating at least two MNOs sharing the P-CSCF node (18).

21. The P-CSCF node (18) of any one of Claims 17-20, wherein the association of the MNO with the P-CSCF node (18) is at least one of: a leasee; and an owner of the P-CSCF node (18).

22. The P-CSCF node (18) of any one of Claims 17-21, wherein the processing circuitry (52) is further configured to: send a registration message to register a user equipment, UE (22), with an Internet Protocol, IP, Multimedia Subsystem, IMS, network, the registration message including the information indicating the MNO associated with the P-CSCF node (18).

23. The P-CSCF node (18) of any one of Claims 17-22, wherein the processing circuitry (52) is further configured to: obtain an IMS network slice identifier associated with the MNO; and send a registration message to register a user equipment, UE (22), with an IMS network, the registration message including the IMS network slice identifier corresponding to the MNO associated with the P-CSCF node (18).

24. The P-CSCF node (18) of Claim 23, wherein the IMS network slice identifier is pre-configured in the P-CSCF node (18).

25. The P-CSCF node (18) of any one of Claims 23 and 24, wherein the IMS network slice identifier identifies an IMS network slice, the IMS network slice using at least the P-CSCF node (18) as an IMS network resource.

26. A Session Management Function, SMF, node (28), the SMF node (28) comprising processing circuitry (62), the processing circuitry (62) configured to: discover a profile of a Proxy-Call Session Control Function, P-CSCF, node (18), the profile including information indicating a mobile network operator, MNO, associated with the P-CSCF node (18), the information indicating the MNO including at least one of: a MNO identifier; and at least one subscriber permanent identifier, SUPI, associated with the MNO.

27. The SMF node (28) of Claim 26, wherein the profile of the P-CSCF node (18) includes information indicating at least two MNOs sharing use of the P- CSCF node (18) as an Internet Protocol, IP, Multimedia Subsystem, IMS, network resource.

28. The SMF node (28) of any one of Claims 26 and 27, wherein the processing circuitry (62) is further configured to: receive a request message for creating a session management context for an IMS packet data unit, PDU, session for a user equipment, UE (22), the request message including information indicating an MNO associated with the IMS PDU session.

29. The SMF node (28) of Claim 28, wherein the processing circuitry (62) is further configured to: obtain MNO subscription information associated with the UE (22) and comparing the obtained MNO subscription information to the information indicating the MNO in the received request message.

30. The SMF node (28) of any one of Claims 28 and 29, wherein the processing circuitry (62) is further configured to: as a result of receiving the request message to create the session management context for the IMS PDU session for the UE (22), use the information indicating the MNO in the received request message to identify the P-CSCF node (18) having the profile associated to the MNO indicated in the received request message.

31. The SMF node (28) of any one of Claims 28-30, wherein the request message includes one of a Nsmf_PDUSession_CreateSMContext request message and a Nsmf_PDUSession_Create request message.

32. The SMF node (28) of any one of Claims 28-32, wherein the request message includes a protocol configuration options, PCO, message, the PCO message including the information indicating the MNO.