WO2023117118A1

WO2023117118A1 - Reporting on services exposed by a visited network to a roaming ue

Info

Publication number: WO2023117118A1
Application number: PCT/EP2021/087584
Authority: WO
Inventors: Massimo CONDOLUCI; Thorsten Lohmar; Tomas Nylander
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2021-12-23
Filing date: 2021-12-23
Publication date: 2023-06-29

Abstract

A method for reporting on network usage of a user equipment, UE, in a service based architecture, SBA, based communication network, wherein the UE is registered with a home network, H-PLMN, of the SBA-based communication network, and wherein the UE is roaming in a visited network, V-PLMN, of the SBA-based communication network; wherein the method comprises the following steps, performed by a network function, NF, in the V-PLMN: collecting service exposure information relating to services exposed by the V-PLMN to the UE, wherein the exposed services relate to the roaming; and providing the service exposure information to the H-PLMN.

Description

Reporting on services exposed by a visited network to a roaming UE

FIELD OF THE INVENTION

The present disclosure generally relates to reporting on services exposed by a visited network to a roaming UE (User Equipment). Particular embodiments relate to a method for reporting on network usage, to a method for keeping track of network usage, to a network node for performing one of those methods, and to a related computer program.

BACKGROUND

Within the automotive industry, the OEMs (Original Equipment Manufacturers) are global, and their vehicles will be present in many different countries. Vehicles are connected to the OEM backend systems which provide telematics and other functions. Such an OEM backend system is often centralized, serving a large area like a complete continent. Cellular connectivity is required for the connected vehicles. Cellular connectivity is provided by local or national Mobile Network Operators (MNOs). OEMs typically rely on existing roaming agreements, since it is impractical to swap SIM cards or swapping eSIM credentials might not be practical for several use cases. Thus, the vehicles will be roaming, i.e. they will be registered with a home mobile network, or shorter: home network (H-PLMN), and connected to a visited mobile network, or shorter: visited network (V-PLMN), in the context of a service-based architecture (SBA) based communication network.

Depending on OEM strategy and MNO support, different types of roaming may be used. In particular, these types include Home Routing (HR) and Local BreakOut (LBO).

- In HR, the user plane is routed back to the home mobile network and Internet access is provided by the home mobile network and only the radio part is used in the visited mobile network.

- In LBO, the user plane is handled by the visited mobile network which also provides the Internet access. On the other hand, the OEMs typically setup their backend systems in a more centralized manner, e.g. a few data centers per region. Of course, hybrid approaches sharing some aspects of HR and some aspects of LBO may be used as well. Hereafter, such approaches may be termed H BO-based hybrid roaming.

It is relevant to consider that different MNOs typically compete against each other. There may therefore be a certain reluctance to share topology information or performance information. An MNO may have a partner relation to an automotive OEM (which may be acceptable, since the two are not competing). As a result, some information may be considered safe to be shared with an OEM, but not safe to be shared with another MNO.

However, when the UE is in roaming condition according to today’s model, the visited network operator relies on the home network to receive payment for any network service offerings. The visited network operator typically has no direct charging relation to the UE (e.g. the vehicle or the OEM). Since usage of network exposure APIs (Application Programming Interfaces) may also become subject for charging, the home operator needs to be aware about the exposure usage. Network exposure services include for instance services offered via a Network Exposure Function (NEF), which includes services for applications to obtain network information (e.g. events, analytics, predictions, etc.), to request specific services (e.g. QoS (Quality of Service), change of policy, specific traffic treatment, etc.). Such services are disclosed in the 3^rd Generation Partnership Project (3GPP) Technical Standards (TS), in particular in 3GPP TS 23.502 §5.2.6, and examples include:

• Event Exposure services, allowing an AF to be notified when a certain event ID (e.g. loss of connectivity, roaming status, PDU session status) occurs.

• Background Data Transfer Policy Negotiation, that allows an AF (Application Function) to negotiate with the mobile network a policy (e.g. time windows, volume to transfer, charging, etc.) for transferring a certain data with relaxed transfer deadlines.

• AF Session with QoS, that allows an AF to interact with the mobile network to request the activation of a specific QoS treatment or a specific policy for a certain traffic. • Analytics Exposure, that allows an AF to receive statistics or predictions for analytics ID of interest (e.g. observed service experience, QoS Sustainability Analytics, network performance analytics) from the mobile network.

Consider the situation that the UE has roamed to a V-PLMN, i.e. it is registered with a H-PLMN and is connected to a V-PLMN. It is noted that that the network entity that generates the network information or notification of interest for the application service (e.g. AMF (Access and Mobility Management Function), NWDAF (Network Data Analytics Function) if considering advances to current 3GPP roaming architectures) is located at the V-PLMN. The network entity that exposes the network information or notification to the application could be e.g. a NEF. The AF interacts with the mobile network to request and obtain the network information or notification, and eventually provides the exposed information I notification to a client application at the UE-side.

The 3GPP technical standards define the HR and LBO roaming cases (cf. 3GPP TS 23.501 and TS 23.502). As a basic difference, in the HR case the user-plane traffic is re-directed from the V-PLMN to the H-PLMN before reaching, e.g. the Internet, whereas in the LBO case the user-plane is not re-directed to the H-PLMN (e.g. there is direct access to the Internet from the V-PLMN). In the present disclosure, exposure services in these two roaming scenarios are considered.

Figure 1 schematically illustrates an example of exposing services in the case of HR. The figure shows an event being produced by an event producer, e.g. AMF in the V- PLMN, and being delivered to an event consumer client, i.e. the UE roaming in the V- PLMN. In the case of HR, the service is delivered via a network exposure function, NEF, in the H-PLMN, via an event consumer, namely an AF in the H-PLMN.

In this example, it is noted that the role of providing the exposure service (e.g. NEF) is located at the H-PLMN. Therefore, the AF interacts with a NEF of the H-PLMN. In this particular example, the service being exposed is an event exposure, but other types of services may also be considered, such as analytics exposure. Figure 2 schematically illustrates an example of exposing services in the case of LBO. The figure shows an event being produced by an event producer, e.g. AMF in the V- PLMN, and being delivered to an event consumer client, i.e. the UE roaming in the V- PLMN. In the case of LBO, the service is delivered via a network exposure function, NEF, in the V-PLMN, via an event consumer, namely an AF in the V-PLMN.

In this example, it is noted that the V-PLMN has the role of providing exposure to the AF, i.e. the AF would be interacting with a NEF located at the V-PLMN. In this particular example, the service being exposed is an event exposure, but other types of services may also be considered, such as analytics exposure.

Figure 3 schematically shows the intermediate step of activation for exposure-related services with LBO roaming to V-PLMN. The figure shows a H-PLMN, a V-PLMN and an OEM cloud, as well as an application (App) client which uses, e.g. a UE in a car. The H-PLMN and the V-PLMN each comprise a NEF as well as various other functions (e.g. AMF, SMF, NWDAF, ...). The figure shows that, in a scenario with LBO-based handling of exposure services when the UE is roaming, the AF (e.g. OEM backend system in the OEM cloud) needs to interact with the exposure service (e.g. NEF) of the V-PLMN, as the required exposure services when the target UE has roamed to V- PLMN will be obtained and handled through the NEF at the V-PLMN (cf. Figure 4). Note that Figure 3 (and Figure 4) use LBO roaming as an example, but that LBO- based hybrid roaming may also be considered.

In particular, Figure 3 shows that, initially, there is a data path “Before roaming”, wherein the NEF of the H-PLMN is involved, and that, subsequently, another data path “After roaming” is set up, connecting the NEF of the V-PLMN directly with the AF of the OEM cloud, wherein the NEF of the H-PLMN is no longer involved.

The resulting situation (i.e. the “After roaming” data path of Figure 3) is shown again in Figure 4 for clarity. Figure 4 therefore clearly shows that in LBO roaming, the H- PLMN is after some point in time no longer involved in the actual exposure of the services exposed by the V-PLMN to the UE. It is noted that, in this setup and as exemplified in Figure 3, the H-PLMN is (or might be) involved in the setup phase of the exposure service between the AF and the NEF in the V-PLMN, e.g. to interact with the V-PLMN to authorize specific network exposure services that the AF should receive when a target UE has roamed to the V-PLMN, but the H-PLMN is not involved in the network exposure service path, i.e. the H-PLMN has no visibility of information relevant to a network service exposed by the NEF in the V- PLMN to the AF.

On the other hand, the H-PLMN will keep its business relationship with the customer to whom the AF belongs (e.g. automotive OEM), and it could be expected that business-related aspects such as charging of used network services will be handled via the H-PLMN because it is simpler for, e.g. an automotive OEM, to have a single relationship with the H-PLMN in a certain area instead of many relationships with many V-PLMNs.

The H-PLMN has the customer/subscriber relation, including also charging for used network services, and consequently the H-PLMN has the task of understanding how to correctly charge a target customer for its usage of network services when roaming to a V-PLMN. Nevertheless, as mentioned hereinabove, the H-PLMN is (or might be) involved in the setup phase of network exposure services when a target UE roams to a V-PLMN, but in an LBO-based exposure service the H-PLMN is not involved any longer in the actual service delivery (e.g. exposure notification of a certain network event or analytics) from the V-PLMN to the AF. For cases when charging of a network exposure service is based on, e.g. number of events I analytics notified or on e.g. number of requests for a certain service, the H-PLMN needs to have some sort of information to generate such charging.

Currently, most of the focus has been on charging whilst roaming for data connectivity, e.g., in 3GPP TS 32.25. For what concerns exposure services, 3GPP TS 32.255 and 3GPP TS 32.254 have been focusing on charging of exposure services, namely Northbound API charging principles and NEFCharginglnformation, considering the case of accessing exposure services in a home network. Currently, there exist no procedures that allow an H-PLMN to know how exposure services are used by a certain customer when connected to a V-PLMN with LBO. For example, a vehicle roaming to a visiting MNO could continue to exploit network services such as exposure of network information but the H-PLMN might not have visibility of whether and how such network services are being used (e.g. how frequently).

SUMMARY

It is an aim of embodiments according to the present disclosure to address the abovedescribed shortcomings of the state of the art.

In particular with regard to exposure of network information such as events and/or analytics I predictions, it is particularly sensitive for an MNO (V-MNO) to share such information with another MNO (H-MNO).

Accordingly, there is provided in a first aspect according to the present disclosure a method for reporting on network usage of a user equipment, UE, in a service based architecture, SBA, based communication network, wherein the UE is registered with a home network, H-PLMN, of the SBA-based communication network, and wherein the UE is roaming in a visited network, V-PLMN, of the SBA-based communication network; wherein the method comprises the following steps, performed by a network function, NF, in the V-PLMN:

- collecting service exposure information relating to services exposed by the V-PLMN to the UE, wherein the exposed services relate to the roaming; and

- providing the service exposure information to the H-PLMN.

In other words, it is an insight of the inventors to introduce the possibility for a H-PLMN to receive information from a V-PLMN on usage of network services by a service consumer while accessing these services via roaming.

Embodiments according to the present disclosure moreover advantageously speed up reporting, as only a limited amount of information is reported from the V-PLMN to the H-PLMN. In other words, by providing service exposure information, and therefore by providing only the necessary information to allow for correct processing at the H- PLMN, the amount of information that needs to be sent is kept limited.

With this solution, V-PLMN provides the H-PLMN with service exposure information. The H-PLMN may in turn use such information to generate the correct charging for the target customer.

Moreover, it is expected that embodiments according to the present disclosure may advantageously help to push the usage of LBO roaming, either “fully” LBO (as defined by 3GPP) or via partial LBO roaming scenarios wherein some functionalities remain handled as per the HR approach but more sensitive services such as exposure of network events and/or analytics are handled with an LBO approach.

In a particular embodiment, the service exposure information comprises at least one of the following, and preferably at most all of the following:

- event exposure information;

- analytics exposure information;

- background data transfer policy negotiation information; and

- information about an application function, AF, session with QoS.

In a particular embodiment, the UE is roaming in the V-PLMN via local breakout, LBO.

- a number of network information exposed to a certain AF in a certain time window;

- a frequency of exposed information; and

- a number and/or frequency of a certain service being requested or modified.

- event exposure information;

- analytics exposure information;

- background data transfer policy negotiation information; - information about an application function, AF, session with QoS;

- a frequency of exposed information; and

- a number and/or frequency of a certain service being requested or modified.

In a particular embodiment, the service exposure information is provided to the H- PLMN according to one or more pre-defined conditions.

Advantageously, this allows to exchange the service exposure information without inducing any overhead.

Examples of such pre-defined conditions may include a pre-defined, fixed time schedule (e.g. daily, weekly or monthly reporting), and/or pre-defined service level agreements (SLA) or other business agreements between the HMO and the VMO.

It is noted that aggregation of service exposure information over such a pre-defined, fixed time schedule may help to ensure that no sensitive information is accidentally leaked, by complicating any analysis of insights that can be gleaned from an individual piece of service exposure information.

In a particular embodiment, the network function in the V-PLMN performing the steps is a network exposure function, NEF, and the services exposed by the V-PLMN to the UE in the roaming are offered via the NEF.

In a particular embodiment, the service exposure information is collected by the NF in such a manner as to withhold any information that has been pre-defined by an operator of the V-PLMN as sensitive information.

In a particular embodiment, the method further comprises:

- inhibiting, by the NF, the inclusion of any information that has been pre-defined by an operator of the V-PLMN as sensitive information in the service exposure information to be provided to the H-PLMN. In a further developed embodiment, the information pre-defined as sensitive information comprises at least one of the following:

- information about a topology of the network;

- network performance metrics, in particular specific network performance metrics such as a throughput performance for a certain UE in a certain area, or a load value in a certain area and time window;

- analytical network information, in particular specific analytical network information such as a historical throughput in a certain area and in a certain time window for a certain QoS flow, a predicted throughput in a certain area and in a certain time window for a certain QoS flow, or a historical or predicted load value in a certain area and time window;

- network-specific charging information, i.e. information on how a certain exposure service would be charged in the network in case of non-roaming; and

- information, either granular or aggregated, on network exposure service usage by other parties not explicitly indicated in the configuration of the H-PLMN.

In a second aspect according to the present disclosure, there is provided a method for keeping track of network usage of a user equipment, UE, in a service based architecture, SBA, based communication network, wherein the UE is registered with a home network, H-PLMN, of the SBA-based communication network, and is roaming in a visited network, V-PLMN, of the SBA-based communication network; wherein the method comprises the following steps, performed by a network function, NF, in the H- PLMN:

- receiving service exposure information from the V-PLMN, wherein the service exposure information relates to services exposed by the V-PLMN to the UE, wherein the exposed services relate to the roaming; and

- processing the service exposure information, in order to keep track at the H-PLMN of services exposed in the V-PLMN to the UE relating to the roaming.

By receiving the service exposure information from the V-PLMN, the H-PLMN is able to keep track of the services exposed in the V-PLMN to the UE relating to the roaming, which it might otherwise not know of, especially in the case of LBO roaming or LBO- based hybrid roaming. It is noted that “keeping track” of exposed services may be used for example for billing, i.e. charging, for auditing, or for any other relevant purpose.

In a particular embodiment, the method further comprises at the H-PLMN:

- sending a subscription message to the V-PLMN in order to receive the service exposure information from the V-PLMN; wherein the subscription message defines one or more conditions that have to be satisfied at the V-PLMN for the V-PLMN to provide the service exposure information to the H-PLMN.

Advantageously, this allows the H-PLMN precise control over when and how the service exposure information is provided.

In a particular embodiment, the method further comprises at the H-PLMN:

- sending a request to the V-PLMN in order to receive, in response to the request, the service exposure information from the V-PLMN.

Advantageously this allows the H-PLMN close to real-time control over when it should receive the service exposure information, e.g. in order to provide up-to-date reporting and charging.

In a particular embodiment, the UE is associated with an application function, AF, in an application layer of the SBA based communication network, and the method further comprises at the H-PLMN:

- receiving verification information from the AF, the verification information serving to verify the service exposure information; and

- verifying the service exposure information based on the verification information.

In this manner, the H-PLMN may request reports on network exposure usage from the AF so that the H-PLMN can perform auditing functions (e.g. check whether usage of network exposure is consistent across the information reported by V-PLMN and AF) using information received from V-PLMN and from the customer’s AF. In a third aspect according to the present disclosure, there is provided a network node in a service based architecture, SBA, based communication network, configured for operating a network function, NF, wherein the NF is configured for performing the steps of the method for reporting on network usage of a user equipment, according to any one of the above described embodiments.

The skilled person will understand that any features and advantages described with respect to the method for reporting on network usage of a user equipment, may apply to this network node, mutatis mutandis.

In a fourth aspect according to the present disclosure, there is provided a network node in a service based architecture, SBA, based communication network, configured for operating a network function, NF, wherein the NF is configured for performing the steps of the method for keeping track of network usage of a user equipment, according to any one of the above described embodiments.

The skilled person will understand that any features and advantages described with respect to the method for keeping track of network usage of a user equipment, may apply to this network node, mutatis mutandis.

In a fifth aspect according to the present disclosure, there is provided a method for verifying network usage of a user equipment, UE, in a service based architecture, SBA, based communication network, wherein the UE is registered with a home network, H- PLMN, of the SBA-based communication network, and is roaming in a visited network, V-PLMN, of the SBA-based communication network; wherein the method comprises the following steps, performed by an application function, AF, in an application layer of the SBA based communication network, wherein the AF is associated with the UE: - optionally receiving a request for verification information serving to verify service exposure information, wherein the service exposure information relates to services exposed by the V-PLMN to the UE, wherein the exposed services relate to the roaming; - sending verification information serving to verify the service exposure information, to a network function, NF, in the H-PLMN.

In a fifth aspect according to the present disclosure, there is provided an application function, AF, in an application layer in a service based architecture, SBA, based communication network, configured for performing the steps of the method for verifying network usage of a user equipment.

The skilled person will understand that any features and advantages described with respect to the method for reporting on network usage of a user equipment, may apply to this method for verifying network usage of a user equipment and to this application function, mutatis mutandis.

In a seventh aspect according to the present disclosure, there is provided a computer program comprising instructions configured for, when executed by a processor of a network node, causing the network node to perform the method for reporting on network usage of a user equipment, according to any one of the above-described embodiments.

The skilled person will understand that any features and advantages described with respect to the method for reporting on network usage of a user equipment, may apply to this computer program, mutatis mutandis.

In an eighth aspect according to the present disclosure, there is provided a computer program comprising instructions configured for, when executed by a processor of a network node, causing the network node to perform the method for keeping track of network usage of a user equipment, according to any one of the above described embodiments.

The skilled person will understand that any features and advantages described with respect to the method for keeping track of network usage of a user equipment, may apply to this computer program, mutatis mutandis. Furthermore, it may be considered to embody the computer program onto a computer program product comprising a computer-readable medium storing the computer program.

Of course, the present invention is not limited to the above-described features and advantages. Indeed, the skilled person will recognize additional features and advantages upon reading the following detailed description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 schematically illustrates an example of exposing services in the case of HR.

Figure 2 schematically illustrates an example of exposing services in the case of LBO.

Figure 3 schematically shows the intermediate step of activation for exposure-related services with LBO roaming to V-PLMN.

Figure 4 reprises the situation of Figure 3 and shows that in LBO roaming, the H-PLMN is after some point in time no longer aware of services exposed by the V-PLMN to the UE.

Figure 5 shows the operation of a method according to the present disclosure, based on the situation of Figure 4.

Figure 6 schematically illustrates an example embodiment 60 of two interacting methods according to the present disclosure.

Figure 7 schematically illustrates a communication diagram 70 representing operation of the embodiment 60 of Figure 6, showing in more detail examples of the operations.

DETAILED DESCRIPTION It is noted that capitalized and uncapitalized terms in the context of the present disclosure should not be construed to have a different meaning. E.g. a network exposure function should not be construed to have a different meaning than a Network Exposure Function.

Figure 5 shows the operation of a method according to the present disclosure, based on the situation of Figure 4, in that the dashed arrow from the NEF of the V-PLMN towards the H-PLMN represents how the NEF of the V-PLMN provides the service exposure information to the H-PLMN. The network function, NF, at the H-PLMN, receiving the service exposure information may e.g. be a NEF, PCF, or another NF interacting with the CCS. In particular, the figure shows that the NEF of the V-PLMN, which is a network function, NF, has collected the service exposure information relating to services exposed by the V-PLMN to the UE, wherein the exposed services relate to the roaming, and provides the service exposure information to the H-PLMN, via the path represented by the dashed arrow.

In other words, some embodiments according to the present disclosure allow reporting on exposure service usage when the UE is in LBO Roaming between a V-PLMN (e.g. a V-NEF) and the home network, so that the home network operator can keep track on how Network Exposure services are used by its customers, in terms of number of transactions I requests, number of notifications, exposed services, exposed events/analytics, etc. This solution also introduces the possibility for the H-PLMN to request a report to an AF on which Network Exposure services it has received from a V-PLMN (and associated information such as number of transactions, etc.), in order to perform auditing of the report received from the V-PLMN, if necessary.

This solution overcomes the problem that a service consumer would need business agreements with many MNOs for exploiting network services while roaming with LBO or with LBO-based hybrid roaming. This solution simplifies the aspect of charging for using network exposure services while roaming, targeting all use cases and verticals for which network services such as exposure while roaming is key (e.g. automotive). This solution may guarantee that an H-PLMN can keep visibility of which and how network exposure services are used by a customer when the H-PLMN is not involved in the delivery of such services, and this consequently gives the H-PLMN the possibility to gather information for properly handling aspects such as charging. This solution also considers that the H-PLMN could trigger specific reports of exposure service usage from its customers, this giving the possibility to the H-PLMN to perform auditing functionalities considering the information received from both V-PLMN and customer.

This solution could also enable accounting among MNOs, giving the possibilities to create a business ecosystem among MNOs for supporting network exposure services during roaming with LBO, with possibilities of enhanced business agreements supported by network exposure service usage reports from a V-PLMN to a H-PLMN

In the context of the present disclosure, the following terminology is used:

• H- refers to a network entity (e.g. network function) located in and I or managed by the H-PLMN;

• V- refers to a network entity (e.g. network function) located in and I or managed by the V-PLMN.

Assume that a network user, i.e. customer (e.g. automotive OEM), has a business relationship with an H-PLMN, and has an AF which can be connected to the H-PLMN, for example to a NEF or to a PCF which then use the Nchf reference point to interact with the converged charging system (CCS) I charging function (CHF). Also assume that the network user/customer has an AF which is connected to the V-NEF (i.e. the NEF of the V-PLMN), AF which receives network exposure services with an LBO approach via the V-NEF for a certain target UE(s) served by the V-PLMN.

In the context of the present disclosure, AF (requesting and obtaining network services) and NEF (exposing and handling network services) may be considered as target network functions. Nevertheless, it is noted that more cases for these interactions could happen, e.g. based on the V2X Application Enabler (VAE) framework (3GPP TS 23.286, TR 23.700-64) where a V2X application specific server (client) could access network exposure services by interacting with a VAE server (client). In the present disclosure, a method is presented that allows a first mobile network (e.g. a H-PLMN) to configure and receive one or more reports from a second mobile network (e.g. a V-PLMN) and, optionally from an application layer (e.g. AF) as a complement, where such reports provide information on which and how (e.g. usage frequency of exposure services, types of used exposure services) network exposure services related to a certain UE(s) associated to the target AF were provided from the V-PLMN to the AF.

The first method of the two interacting methods is implemented at a V-PLMN 68, in this particular example at a NEF 61 (which is a type of NF) of the V-PLMN 68. The second method of the two interacting methods is implemented at a H-PLMN 69, in this particular example at a NF 62 of the H-PLMN 69 (which NF 62 may e.g. be a PCF, a NEF, etc.). By interacting, the two methods allow not only to report on network usage of a user equipment (not shown in Figure 6, but may e.g. be the UE of Figures 3-5), but also to keep track of that network usage.

The communication network to which the V-PLMN 68 and the H-PLMN 69 belong, is a service based architecture, SBA, based communication network, e.g. the 5G network for mobile communication. In the context of Figure 6, the UE is considered to be registered with the H-PLMN 69, and the UE is roaming in the V-PLMN 68.

In optional step 64, the H-PLMN may configure a Exposure Service Usage Report from the V-PLMN. Optionally also the H-PLMN may configure a Exposure Service Usage Report from the from AF 63.

The Exposure Service Usage Report configured in step 64 is service exposure information, in the sense that it relates to services exposed by the V-PLMN 68 to the UE, wherein the exposed services relate to the roaming of the UE. Note that step 64 is optional in the sense that the V-PLMN may have been provided beforehand with a template and schedule according to which the V-PLMN may autonomously collect and provide the service exposure information.

The configuration of Exposure Service Usage Report may include, but is not limited to, the following:

• List of exposure services that should be reported. This may be a list of exposure services, such as, but not limited to, Event Exposure services possibly with indications about specific event IDs of interest for the reporting (e.g. loss of connectivity, PDU session status), Background Data Transfer Policy Negotiation, AF Session with QoS possibly with indications about specific policies of interest for reporting, Analytics Exposure possibly with indications about specific event Analytics of interest for the reporting (e.g. observed service experience, QoS Sustainability Analytics, network performance analytics).

• List of targets, indicating whether reports should be provided only for a certain UE(s). This may be expressed in the form of e.g. GPSI, SUPI, External Group Identifier, or Internal Group Identifier.

• (if the configuration targets a V-PLMN) List of AFs, indicating that the report should refer to usage of exposure services provided by the V-PLMN to the listed AF(s). This may be in the form of IP address(es), etc.

• (if the configuration targets an AF) List of V-PLMNs, indicating that the report should refer to usage of exposure services received from the AF by the listed V-PLMN(s). This may be in the form of PLMN ID(s), or in the form of URI(s), URL(s), FQDN(s), IP address(es) associated to the exposure functions of the V-PLMN(s) under consideration.

• Report receiver, including information such as FQDN(s), URI(s), URL(s), IP address(es), NF ID(s) identifying the network entity/entities interested in receiving the Exposure Service Usage Report, and/or in the form of a charging I Exposure Service Usage Report context identifier.

• Report configuration, indicating how V-PLMN / AF should perform the reporting. Examples include, but are not limited to, whether a single report should be periodic and include information on exposure service usage over a certain time period (e.g. a daily-sent report including information on exposure usage over the last 24 hours), whether a single report should be triggered every time a single exposure service is provided, etc.

• Report filters, indicating whether the monitoring of exposure service for usage reporting should be performed in specific cases. Examples include, but not limited to, whether exposure service usage counting should be triggered in certain time windows, whether exposure service usage counting should be triggered only after a certain number of usage occasions (e.g. reporting should start after X occasions of exposure service), etc.

The configuration of Exposure Service Usage Report could be provided in different ways.

• One example is via one or more pre-defined conditions, e.g. a semi-static configuration based on, e.g. business agreements among H-PLMN and V- PLMN/AF where the agreement would include information such as the ones listed above plus other information such as APIs/URIs/URLs/IP address(es) to be used for the reporting.

• Another example is via a subscription-based approach, wherein the H-PLMN sends a subscription message to the V-PLMN in order to receive the service exposure information from the V-PLMN, wherein the subscription message defines one or more conditions that have to be satisfied at the V-PLMN for the V-PLMN to provide the service exposure information to the H-PLMN. In a practical example of such an approach, a system operation may allow the H- PLMN (e.g. a NEF or another network function such as PCF interacting with CCS or another network entity having charging I accountability functionalities) to send an “Exposure Service Usage Report Subscription Request” to V-PLMN (e.g. a NEF) (optionally to AF), request which includes the fields indicated above where the fields report configuration and report filters would indicate when an notification should be triggered. In this example, the V-PLMN (e.g. a NEF) I AF may reply (upon checking whether the request could be authorized for the case of request received by V-PLMN) with “Exposure Service Usage Report Subscription Response” to H-PLMN indicating whether the request has been accepted or not. • In another example, a request-based approach could be used wherein the H- PLMN sends a request to the V-PLMN in order to receive, in response to the request, the service exposure information from the V-PLMN. In a practical example of such an approach, a system operation may allow the H-PLMN (e.g. a NEF or another network function such as PCF interacting with CCS or another network entity having charging I accountability functionalities) to send a “Exposure Service Usage Report Request” to V-PLMN (e.g. a NEF) (optionally to AF), request which includes the fields indicated above. In this example, the V-PLMN (e.g. a NEF) I AF may reply (upon checking whether the request could be authorized for the case of request received by V-PLMN) with “Exposure Service Usage Report Response” to H-PLMN providing the reports as indicated in the request.

It is noted that configuration of Exposure Service Usage Report may be different for V-PLMN and AF. For example, the list of exposure services to be reported by V-PLMN and AF may be different. Furthermore, their setup may differ, e.g. a semi-static or a subscription-based configuration may be used with the V-PLMN, whereas a requestbased configuration may be used with the AF.

The H-PLMN may trigger a request I subscription of Exposure Service Usage Report based on a multitude of occasions. Examples include but are not limited to:

• Semi-static triggers based on business agreements with V-PLMNs and customers (i.e. the H-PLMN knows based on its business agreements from which V-PLMNs it should receive an Exposure Service Usage Report and for which customers/AFs).

• Roaming-status triggers, e.g. where a H-PLMN may monitor the roaming status of target UE(s) associated to AF(s) of a customer (e.g. by subscribing to “roaming status” Event Exposure), and when the H-PLMN receives the information that a target UE has roamed to a certain V-PLMN, this may trigger the request I subscription of Exposure Service Usage Report towards the V- PLMN (or an update of a previously sent request I subscription).

• Usage Report based triggers, e.g. the H-PLMN may decide whether to request an Exposure Service Usage Report from an AF (or multiple AFs) based on a usage report received from a certain V-PLMN (or multiple V-PLMNs). For instance, the H-PLMN may decide to do this because of auditing reasons, e.g. to compare the usage reports from V-PLMN and AF to verify, i.e. to double check, whether there is any information mismatch. This is linked to the processing of the usage report from the V-PLMN which is performed by the H- PLMN.

It is noted that triggers of a request I subscription of Exposure Service Usage Report from V-PLMN and AF may be different, e.g. the usage report from V-PLMN may be triggered based e.g. on business agreements or on roaming-status whereas the usage report from AF may be triggered based on some processing by the H-PLMN of the usage report from V-PLMN.

In step 65, V-PLMN 68 collects and optionally processes the service exposure information, i.e. usage information on exposure service(s) exposed to AF and, if requested by the H-PLMN, the AF also collects and optionally processes service exposure information, i.e. information on exposure service(s) received from V-PLMN based on the configuration agreed with the H-PLMN. In this step, when the V-PLMN (e.g. NEF) provides a target network exposure service to target AF(s) related to target UE(s), then the V-PLMN (e.g. NEF) may collect such information and may optionally process it for being able to later generate the report to be provided to H-PLMN. Similarly, if previously requested by H-PLMN, the AF may collect information on target network exposure services accesses via target V-PLMN(s) related to target UE(s), then the AF optionally processes it for providing it to H-PLMN. The processing may for example include aggregation of data over a certain time window, filtering and translation of information, adding additional information such as metadata associated to reported exposure services.

In step 66, the V-PLMN 68, and the AF 63 if requested, provide the service exposure information to the H-PLMN 69, i.e. they provide the H-PLMN 69 with Exposure Service Usage Report based on the configuration agreed with H-PLMN 69. It is noted that reporting from V-PLMN 68 and AF 63 may happen at two different moments, and that there may not necessarily be one-to-one mapping between a report from the V-PLMN and from the AF (e.g. the V-PLMN may provide multiple reports and the AF only one or a few, potentially covering in the report only a subset of exposure services w.r.t. those reported by the V-PLMN). The reporting may be triggered based on the agreed configuration, e.g. directly when target exposure services are provided from V-PLMN to AF, periodically for instance by sending a notification through an “Exposure Service Usage Report” system operation, as response to a report request from H-PLMN for instance by sending a response through an “Exposure Service Usage Report” system operation. The report may include an indication to the charging I Exposure Service Usage Report context identifier signaled by the H-PLMN, together with usage report information.

Obviously, as the V-PLMN 68 provides 66 the service exposure information to the H- PLMN 69, the H-PLMN 69 (in particular a NF 62 in the H-PLMN 69) receives 66 the service exposure information in the same operation.

In step 67, the H-PLMN 69 processes the service exposure information, i.e. the reports, received from the V-PLMN 68. Examples of processing include checking whether SLAs are fulfilled and I or to generate the correct charging for the exposure service services used by the AF at the V-PLMN. Another example of processing is calculating the correct charging based on the received reports and business agreements towards the customer of the AF(s) as well as towards the V-PLMN(s). A further example of processing is understanding whether auditing of the usage report from the V-PLMN should be performed (for instance based on a random selection, or because the usage report shows unexpected figures such as too high usage of a certain exposure service, or because the usage report shows a too high discrepancy w.r.t. last report such as the usage of an exposure service has doubled in a certain time window but the number of target UE(s) didn’t change in such window). In this case, the H-PLMN may decide to request service exposure information, i.e. an Exposure Service Usage Report, from the target AF(s) for the sake of comparing this with the report received from the V-PLMN(s) to understand whether they match, e.g. to make sure that the V-PLMN(s) doesn’t/don’t report a higher usage of exposure services from AF(s) than the actual one as well as to make sure that the AF(s) doesn’t/don’t report a lower usage of exposure services from the V-PLMN(s) than the actual one.

Figure 7 schematically illustrates a communication diagram 70 representing operation of the embodiment 60 of Figure 6, showing in more detail examples of the operations performed by the NF 71 of the V-PLMN 78 (corresponding with NF 61 of V-PLMN 68 in Figure 6), by the NF 72 of the H-PLMN 79 (corresponding with NF 62 of V-PLMN 69 in Figure 6), and by the AF 73 (corresponding with AF 63 in Figure 6).

In this particular example, the figure shows in detail how the NF 72 in the H-PLMN 79 optionally sends 701 a subscription request for the Service Exposure Usage Report, i.e. the service exposure information, to the NEF 71 (which is a type of NF) in the V- PLMN 78. The subscription request may optionally be processed at the NEF 71 , and a subscription response may optionally be sent in response to the subscription request.

The figure shows that the NEF 71 in the V-PLMN 78 may collect 702 (and if necessary process) the service exposure information, i.e. the information relating to the usage of any one or more services related to one or more target UEs exposed to one or more target AFs.

After collecting 702 the service exposure information, the NEF 71 in the V-PLMN 78 may provide 703 the service exposure information to the H-PLMN 79, in particular to a NF 72 in the H-PLMN 79.

Obviously, as the V-PLMN 78 provides 703 the service exposure information to the H- PLMN 79, the H-PLMN 79 (in particular the NF 72 in the H-PLMN 79) receives 703 the service exposure information in the same operation.

Subsequently, the H-PLMN 79 may process 704 the received service exposure information, for example in order to keep track at the H-PLMN 79 of services exposed in the V-PLMN 68 to the UE relating to the roaming. Additionally and optionally, as a self-contained method for verifying network usage of the UE, the H-PLMN may request 705 verification information from an AF 73, as was described above with reference to Figure 6. This request may be processed by the AF 73, which may collect 706 and optionally process the verification information, which may for example be configured to have the same format as the service exposure information provided 703 by the V-PLMN 78 to the H-PLMN 79, or which may have another suitable format.

The AF 73 may subsequently send 707 the verification information in response to the request, in order to allow the H-PLMN 79 to verify the service exposure information based on the received verification information.

Of course, the skilled person will understand that the present invention may be implemented in other ways than those specifically set forth herein without departing from the essential characteristics of the invention. The embodiments described herein are thus to be considered in all respects as illustrative and not restrictive, and all changes within the scope of the appended claims are intended to be embraced therein.

Abbreviations:

AF Application Function

AMF Access and Mobility Management Function

CCS Converged Charging System

CHF Charging Function

FQDN Fully Qualified Domain Name

GPSI Generic Public Subscription Identifier

HR Home Routing

LBO Local Breakout

MNO Mobile Network Operator

NEF Network Exposure Function

NWDAF Network Data Analytics Function

OEM Original Equipment Manufacturer

PCF Policy Control Function

PLMN Public Land Mobile Network SUPI Subscription Permanent Identifier

H-PLMN Home Public Land Mobile Network

UE User Equipment

URI Uniform Resource Identifier URL Uniform Resource Locator

VAE V2X Application Enabler

V-PLMN Visited Public Land Mobile Network

Claims

25 CLAIMS

1. A method for reporting on network usage of a user equipment, UE, in a service based architecture, SBA, based communication network, wherein the UE is registered with a home network, H-PLMN, (69) of the SBA-based communication network, and wherein the UE is roaming in a visited network, V-PLMN, (68) of the SBA-based communication network; wherein the method comprises the following steps, performed by a network function, NF, (61) in the V-PLMN:

- collecting (65) service exposure information relating to services exposed by the V- PLMN (68) to the UE, wherein the exposed services relate to the roaming; and

- providing (66) the service exposure information to the H-PLMN (69).

2. The method of claim 1 , wherein the service exposure information comprises at least one of the following:

- event exposure information;

- analytics exposure information;

- background data transfer policy negotiation information; and

- information about an application function, AF, session with QoS.

3. The method of any previous claim, the UE is roaming in the V-PLMN (68) via local breakout, LBO.

4. The method of any previous claim, wherein the service exposure information comprises at least one of the following:

- a frequency of exposed information; and

- a number and/or frequency of a certain service being requested or modified.

5. The method of any previous claim, wherein the service exposure information is provided to the H-PLMN (69) according to one or more pre-defined conditions.

6. The method of any previous claim, wherein the network function (61) in the V-PLMN performing the steps is a network exposure function, NEF, (61) and wherein the services exposed by the V-PLMN (68) to the UE in the roaming are offered via the NEF (61).

7. The method of any previous claim, wherein the service exposure information is collected by the NF (61) in such a manner as to withhold any information that has been pre-defined by an operator of the V-PLMN (68) as sensitive information.

8. The method of any previous claim, comprising:

- inhibiting, by the NF (61), the inclusion of any information that has been pre-defined by an operator of the V-PLMN (68) as sensitive information in the service exposure information to be provided to the H-PLMN (69).

9. The method of claim 7 or claim 8, wherein the information pre-defined as sensitive information comprises at least one of the following:

- information about a topology of the network;

- network performance metrics;

- analytical network performance metrics, either historical or predicted;

- network-specific charging information; and

10. A method for keeping track of network usage of a user equipment, UE, in a service based architecture, SBA, based communication network, wherein the UE is registered with a home network, H-PLMN, (69) of the SBA-based communication network, and is roaming in a visited network, V-PLMN, (68) of the SBA-based communication network; wherein the method comprises the following steps, performed by a network function, NF, (62) in the H-PLMN (69):

- receiving (66) service exposure information from the V-PLMN (68), wherein the service exposure information relates to services exposed by the V-PLMN (68) to the UE, wherein the exposed services relate to the roaming; and

- processing (67) the service exposure information, in order to keep track at the H- PLMN (69) of services exposed in the V-PLMN (68) to the UE relating to the roaming.

11. The method of claim 10, comprising at the H-PLMN (69):

- sending a subscription message to the V-PLMN (68) in order to receive the service exposure information from the V-PLMN (68); wherein the subscription message defines one or more conditions that have to be satisfied at the V-PLMN (68) for the V-PLMN (68) to provide the service exposure information to the H-PLMN (69).

12. The method of any one of claims 10-11 , comprising at the H-PLMN (69):

- sending a request to the V-PLMN (68) in order to receive, in response to the request, the service exposure information from the V-PLMN (68).

13. The method of any one of claims 10-12, wherein the UE is associated with an application function, AF, (63) in an application layer of the SBA based communication network; the method comprising at the H-PLMN (69):

- receiving (66) verification information from the AF (63), the verification information serving to verify the service exposure information; and

14. A network node in a service based architecture, SBA, based communication network, configured for operating a network function, NF, wherein the NF is configured for performing the steps of the method of any one of the claims 1-13.

15. A method for verifying network usage of a user equipment, UE, in a service based architecture, SBA, based communication network, wherein the UE is registered with a home network, H-PLMN, (69) of the SBA-based communication network, and is roaming in a visited network, V-PLMN, (68) of the SBA-based communication network; wherein the method comprises the following steps, performed by an application function, AF, (63) in an application layer of the SBA based communication network, wherein the AF (63) is associated with the UE:

- optionally receiving a request for verification information serving to verify service exposure information, wherein the service exposure information relates to services exposed by the V-PLMN (68) to the UE, wherein the exposed services relate to the roaming; 28

- sending (66) verification information serving to verify the service exposure information, to a network function, NF, (62) in the H-PLMN (69).

16. An application function, AF, (63) in an application layer in a service based architecture, SBA, based communication network, configured for performing the steps of the method of claim 15.

17. A computer program comprising instructions configured for, when executed by a processor of a network node, causing the network node to perform the method of any one of the claims 1-13 and 15.