Patent Description:
A Universal Mobile Telecommunications System (UMTS) is a third generation (<NUM>) telecommunication network, which evolved from the second generation (<NUM>) Global System for Mobile Communications (GSM). Specifications for the Evolved Packet System (EPS), also called a Fourth Generation (<NUM>) network or Long Term Evolution (LTE), have been completed within the 3rd Generation Partnership Project (3GPP) and this work continues in the coming 3GPP releases, for example to specify a Fifth Generation (<NUM>) New Radio (NR) network.

3GPP TS <NUM> defines Stage <NUM> system architecture for <NUM> System. One of the new features introduced in the area of user equipment (UE) mobility consists of supporting Mobility Restrictions. Mobility Restrictions restrict mobility handling or service access of a UE. Mobility Restrictions consists of Radio Access Technology (RAT) restriction, Forbidden Area, Service Area Restrictions (SAR) and Core Network type restriction.

The core network determines the Mobility Restrictions based on UE subscription information, UE location and local policy. <NUM> Core Network Functions (NFs) comprises the following nodes:.

The UDM stores the Service Area Restrictions of a UE as part of the UE's subscription data. The PCF in the serving network may e.g. due to varying conditions such as UE's location, application in use, time and date further adjust Service Area Restrictions of a UE. In this respect, 3GPP TS <NUM> V16. <NUM> defines a policy and charging control framework for the <NUM> System. During registration, if the Service Area Restrictions of the UE is not present in the AMF, the AMF fetches from the UDM the Service Area Restrictions of the UE that may be further adjusted by the PCF. The serving AMF shall enforce the Service Area Restrictions of a UE. For more details, see 3GPP TS <NUM>, chapter <NUM>. In addition, <CIT>) discloses the AMF fetching subscription data from a UDM for a UE.

Access and mobility restrictions are not specified by 3GPP in <NUM>, but implemented mainly by node specific configuration, which created a lot of vendor specific implementations.

Registration area management in <NUM> is based on the concept of mobility restrictions, with the objective to restrict mobility handling or service access of a UE. For example:.

However, the current solution in 3GPP is limited to define either allowed or non-allowed areas. In addition, Allowed or Non-allowed areas apply to UE communication capability regardless of network slicing. 5GC network handles service area restrictions during registration and handover procedures, after network slice selection procedures. The AMF assigns service area restrictions to a UE that apply to all network slices the UE is currently attached to. Finally, service area restrictions are statically defined in the UDM and can only be adjusted by the PCF via operator policies.

Therefore it is an object of the invention herein to improve handling access and mobility restrictions in a communication system.

According to one aspect of embodiments herein, the object is achieved by an AMF node and method performed therein in a core network for dynamically handling access and mobility service areas with different capabilities in a communication system. The AMF node transmits to a UDM node, a subscription data request for a UE communication. The AMF node receives from the UDM node, subscription data with SAR data for the UE. The SAR data includes a number of service areas allowed or restricted for the UE and, for each service area, a service area identifier, a service area type and a service area definition. The service area type may be any one of: secure area, sponsored area, parental control area and dynamic area. The AMF node transmits to a PCF node, a policy request for the UE. The AMF node receives from the PCF node a policy response with a Service Area Definition (SAD) rule for the UE. The SAD rule comprises a service area definition and an indication of a set of service area characteristics enabled in the service area. The AMF node then take actions for the UE communication based on anyone of the SAR data, the SAD rule and local policies at the AMF node.

According to one aspect of embodiments herein, the object is achieved by a UDM node and method performed therein in a core network for dynamically handling access and mobility service areas with different capabilities in a communication system. The UDM node configures SAR data for a UE. The SAR data includes a number of service areas allowed or restricted for the UE and, for each service area, a service area identifier, a service area type and a service area definition. The UDM node receives from the AMF node, a subscription data request for the UE and transmits to the AMF node the subscription data with the SAR data for the UE.

As a part of developing embodiments herein some problems or limitations associated with the existing solutions will be first identified and discussed.

As discussed in the background, the current solution in 3GPP is limited to define either allowed or non-allowed areas. There is no means to define service areas with restricted capabilities e.g. a Secure Area with limited functionality or with additional security checks. The limitation of Service Area Restriction (SAR) of providing service in limited manner, i.e. Allowed & Not-Allowed only, is addressed according to embodiments herein.

In addition, Allowed or Non-allowed areas apply to UE communication capability regardless of network slicing. The PCF may further adjust Service Area Restrictions of a UE, but the update also applies to all network slices the UE is using.

Access and mobility restrictions are not specified by 3GPP in <NUM>, but implemented mainly by node specific configuration. For example, the applicant has provided a proprietary solution with a dedicated interface between mobility management entity (MME) and Policy and Charging Rules Function (PCRF) for location-based policy control. However, this interface does not handle service area restrictions, as defined in <NUM>, but enables use cases such as:.

There is no mechanism for over-the-top Adaptation Function (OTT/AF) to manage service area restrictions. Such mechanism will allow OTT/AF to create, modify, or remove service area restrictions on demand well suited for business cases driven by Enterprise or OTT/AF.

Therefore according to embodiments herein, it is proposed to extend the concept of Service Area Restrictions (SAR), to allow flexible definition of service areas with different capabilities, for specific network slices, that can also be managed on demand by OTT/AF via NEF service exposure.

Flexible Service Area can provide Network operator to manage the access & mobility function on certain triggers which are not fully utilized. There are many scenarios where different treatment of services is required based on Service Area requested.

To describe this functionality, following examples of Service Areas may be considered:.

All new service areas defined above are more or less static in nature and predefined. Having said that, these Service areas can be dynamic in nature which can be changed or modified on the fly by operator or enterprise as per their use case and same is highlighted below.

Dynamic Areas: All Service Areas can be used for static as well as dynamic Service area. For example, if considering Secure Area, this is similar to above service area, but this area might get modified dynamically. For example, if a president or king's envoy is moving to other location, e.g. from Palace to airport, then all the subscribers entering that area may be updated as per the Secure Area Policies.

These areas may be implemented in two ways:.

It is also possible to use a combination of both of the above. Some area types maybe defined as universal types, e.g. <NUM> to <NUM> and remaining service areas may be set as operator defined.

To implement the flexible Service Area, new parameters in UE subscription as well as update on PCF to AMF interface are proposed according to embodiments herein. This has impacts in both, the call flow for Registration and Session creation.

<FIG> illustrates a communication system <NUM> comprising a number of network nodes. The communication system <NUM> comprises a core network <NUM> comprising a number of core network function nodes, such as an AMF node <NUM>, a UDM node <NUM>, a PCF node <NUM>, an AF/NEF node <NUM>, a SMF node <NUM> etc. The communication system <NUM> further comprises a number of UEs and base stations, where a UE <NUM> and a base station <NUM> are shown.

Access and mobility service areas consist of a set of tracking areas where a UE is allowed to register and establish communication services with certain capabilities that make it suitable for certain scenarios or applications. For example, the operator may need to define certain service areas to provide communication services to the government or sensitive agencies that require fulfilling stringent security protocols. In such "secure areas" the network enables certain functionalities that are not typically required in the whole PLMN or network slice, such as secondary authentication or authorization, UE tracing and logging, lawful interception, etc..

As described above, a few examples of service areas with specific capabilities may be Secure Area with limited capacity and additional security features, Sponsored Area where OTT/AF can create, remove or manage the respective service area, Parental Control Area where certain types of content can be blocked for all subscribers. All Service Areas may be used for static as well as dynamic Service area where different capabilities may be modified dynamically.

A method for dynamically handling access and mobility service areas with different capabilities in a communication system <NUM> according to embodiment herein may be implemented in a core network, e.g. the core network <NUM>. The method may be carried out at the AMF node <NUM> and will be described with reference to <FIG>. The method comprises the following actions which may be performed in any suitable order.

When a UE, e.g. the UE <NUM> enters into service areas of a base station, the AMF node <NUM> receives a registration request from the UE via the base station <NUM>. After the registration request, in order to handle the communication for the UE <NUM>, the AMF node <NUM> transmits to the UDM node <NUM>, a subscription data request for the UE <NUM> communication. At the UDM node, the Service Area Restriction (SAR) data for a subscriber includes a number of service areas allowed or restricted for the subscriber. Further, for each service area, the UE's subscription data in the UDM includes a service area identity, a service area type and a service area definition.

The AMF node <NUM> receives from the UDM node <NUM>, subscription data with Service Area Restriction (SAR) data for the UE. The SAR data includes a number of service areas allowed or restricted for the UE and, for each service area, a service area identifier, a service area type and a service area definition. The service area definition may be specified by using explicit Tracking Area identities (TAls).

The number of service areas allowed or restricted for the UE indicates respective services allowed or restricted for the UE in each service area.

The service area type may be any one of secure area, sponsored area, parental control area and dynamic area.

The service area definition may comprise one or more TAls identifying one or more Tracking Areas (TAs) that the service area comprises.

The AMF node <NUM> may determine a set of service area characteristics, i.e. a set of functionalities enabled in the service area by means of the configuration SAR data received from the UDM node <NUM>, e.g. by mapping the service area identity and type to a pre-configured set of functionalities using, e.g. enumerated lists of different types of services areas representing Secure area, Sponsored area, Parental Control Area etc., or during interactions with the PCF node <NUM>.

The service area characteristics may comprise any one or any combination of elements listed in the following:.

The core network may determine access and mobility service areas based on dynamic information received from the PCF node <NUM>. In this case, the AMF node <NUM> may determine a set of service area characteristics during the interactions with the PCF node <NUM>. The AMF node <NUM> transmits to the PCF node <NUM>, a policy request about access and mobility service areas for the UE <NUM>.

The AMF node <NUM> receives, from the PCF node <NUM>, a policy response with a Service Area Definition (SAD) rule for the UE <NUM>. The SAD rule comprises a service area definition and an indication of a set of service area characteristics enabled in the service area.

The SAD rule may also comprise one or more Network Slice Selection Assistance Information (NSSAI) that the service area applies to.

The AMF node <NUM> takes actions for the UE communication based on anyone of the SAR data, the SAD rule and local policies at the AMF node.

The local policies at the AMF node <NUM> may define default values of the SAD rule when not provided by the PCF, and/or specify default actions to be taken for specific services areas or TAls.

The AMF node <NUM> may take actions as per the Selected Service Area defined by TAls. These actions may include, but not limited to:.

According to embodiments herein, a method carried out at a UDM node <NUM> in a core network for dynamically handling access and mobility service areas with different capabilities in a communication system, will be described with reference to <FIG>. The method comprises the following actions:.

The UDM node <NUM> configures SAR data for a UE <NUM>. The SAR data includes a number of service areas allowed or restricted for the UE <NUM> and, for each service area, a service area identifier, a service area type and a service area definition. The number of service areas allowed or restricted for the UE indicates respective services allowed or restricted for the UE in each service area. The service area type may be any one of secure area, sponsored area, parental control area and dynamic area. The service area definition may comprise one or more tracking area identifier (TAI) identifying one or more TA that the service area comprises.

The UDM node <NUM> receives from an AMF node <NUM> a subscription data request for the UE <NUM>.

The UDM node <NUM> transmits to the AMF node <NUM> subscription data with the SAR data for the UE <NUM>.

According to embodiments herein, a method carried out at a PCF node <NUM> in a core network <NUM> for dynamically handling access and mobility service areas with different restrictions capabilities in a communication system <NUM>, will be described with reference to <FIG>. The method comprises the following actions:.

The PCF node <NUM> configures a Service Area Definition (SAD) rule for a UE. The SAD rule comprises a service area definition, e.g. a list of TAls, and an indication of a set of service area characteristics enabled in the service area.

The SAD rule may comprise one or more Network Slice Selection Assistance Information (NSSAI) that the service area applies to, e.g. a list of S-NSSAIs.

The SAD rule may further comprise events that trigger a re-evaluation of the access and mobility service area policies, e.g. location change, change of allowed S-NSSAI, etc..

The PCF may configure the SAD rule based on the information received from the AMF node <NUM> in the AM Policy Association, static configuration, e.g. operator policies or during interaction with OTT/AF via a NEF node.

The PCF node <NUM> receives from the AMF node <NUM>, a policy request for the UE <NUM>.

The PCF node <NUM> transmits to the AMF node <NUM>, a policy response with the SAD rule for the UE <NUM>.

When the PCF node <NUM> configures the SAD rule, e.g. determines a set of service area characteristics, i.e. the set of functionalities enabled in the service area during interactions with the OTT/AF. The method may further comprise the following actions:.

The PCF node <NUM> may receive a Service Area Profile from provisioning system used by the service provider to update the configuration and subscription data in the core network nodes. Provisioning system uses Command Line Interface (CLI) or Application Programming Interface (API) to directly make configuration changes in the core network nodes.

The PCF node <NUM> may receive a Service Area Profile from the NEF node <NUM>. The NEF node <NUM> may receive the Service Area Profile from any one of Operator Application Function, OTT Application Function, Data Analytics Function or Government Regulatory body.

The OTT/AF via the NEF node <NUM> may issue requests to the PCF node <NUM> to manage, e.g. create, modify, or remove access and mobility service areas. The OTT/AF may issue requests on behalf of applications not owned by the PLMN serving the UE. In this case, the method may further comprise the following actions:.

The PCF node <NUM> may create a service area on-demand based on the received Service Area Profile.

To create a service area, the OTT/AF provides a Service Area Profile, which may include:.

The PCF node <NUM> may update dynamically Service Area Restriction based on the received Service Area Profile. The PCF node <NUM> may update type of Service Area where a subscriber is currently located. It may also update the Service Area itself. These inputs regarding service area may be provided by the provisioning system or by the NEF node <NUM>.

The external Application Function (AF) may not be aware of the network based location details, i.e. TAls, cells, base stations gNBs etc. So, it may provide the actual geographical location, e.g. Latitude & Longitude to NFs. But NFs do not understand these details. So, mapping of these parameters is needed. This may be done at the NEF node or may be at the PCF node.

Option <NUM>: First, mapping between geographical location e.g. Latitude & longitude, and Network location e.g. TAls, is done via provisioning system. Then provisioning system updates the PCF node or NEF node with the mapping of geographical location and Network location. It may be decided based on solution deployment, at which point this mapping will be done. This means that translation from geographical location to network location TAls may also be done at the NEF or at the PCF as alternative.

The AF may provide Service Area Profile with a message Nnef_ParameterProvision_Update to the NEF node <NUM>. The Service Area Profile may include:.

The NEF node <NUM> then updates the PCF node <NUM> about SAR. It may use the same location information provided by the AF or it may provide a list of TAls based on where the mapping is configured.

Based on the mapping, the PCF node <NUM> then updates other NFs, e.g. AMF node <NUM> or SMF node about SAR. Procedures between the PCF node and other NFs will be described in the following section.

Option <NUM>: The Service Area Profile may be directly provisioned in the PCF node <NUM> by the provisioning system instead of providing it as a part of service request from the NEF node <NUM>.

According to embodiments herein, a method carried out at a SMF node, e.g. the SMF node <NUM> in a core network for dynamically handling access and mobility service areas with different capabilities in a communication system <NUM> will be described with reference to <FIG>. The method comprises the following actions:.

The SMF node <NUM> receives from the AMF node <NUM>, a session request for a UE communication. The session request includes service area related information with a service area identifier and a service area type. The service area related information may comprise any one of:.

The SMF node <NUM> transmits to the PCF node <NUM> a policy request for the UE <NUM>.

The SMF node <NUM> receives from the PCF node <NUM>, a policy response with a Service Area Definition (SAD) rule for the UE <NUM>. The SAD rule comprises a service area definition and an indication of a set of service area characteristics enabled in the service area.

The set of service area characteristics may comprise any one of:.

The SMF node <NUM> takes actions for the UE communication based on the SAD rule, the information received from the AMF node (<NUM>) and/or local policies at the SMF node <NUM>. That is, in relation to the access and mobility service areas, the SMF node <NUM> combines the input received from the AMF node <NUM> with the input received from the PCF node and/or own information.

In the following, signaling flows for Registration and Session creation are described to see the impact of adding new capabilities related to the definition of flexible Service Areas.

<FIG> shows an updated signaling flow for Registration procedure. A method performed in a core network <NUM> for dynamically defining access and mobility service areas during registration procedure a communication system <NUM> will be described with reference to <FIG>.

As described above, the following configurations are made at the UDM node <NUM> and the PCF node <NUM>:.

The method comprises the following steps or actions:.

The service area characteristics may comprise any one of:.

<NUM>: The AMF node <NUM> takes actions based on anyone of the SAR data, the SAD rule and local policies at the AMF node.

The AMF node <NUM> may take actions to make service changes as per the Selected Service Area defined by TAls. These actions may include, but not limited to:.

<NUM>: After this, the AMF node <NUM> determines if the registration request is accepted or rejected based on the requirement of the service area and informs the UE <NUM>.

<FIG> shows an updated signaling flow for Session Management. A method performed in a core network <NUM> for dynamically defining access and mobility service areas during session management procedure a communication system <NUM> will be described with reference to <FIG>.

For example, the AMF node <NUM> sends a PDU Session Establishment Request by sending a Nsmf_PDUSession_CreateSMContext Request message to the SMF node <NUM> including Subscription Permanent Identifier (SUPI), Data Network Name (DNN), S-NSSAI, PDU Session ID, AMFID, Access Network Type (ANType), Request Type, SMContextStatusUri, N1 SM container etc. parameters as described in 3GPP TS <NUM>. The request creates an individual SM context for a given PDU. The Service Area related information may be included in the Nsmf_PDUSession_CreateSMContext Request message.

The Service Area related information may include:.

<NUM>: The SMF node responds with a Nsmf_PDUSession_CreateSMContext Response message to the AMF node <NUM> including SM Context ID. The AMF node <NUM> receives from the SMF node the response message.

<NUM>: If dynamic PCC is deployed, the SMF node performs a PCF selection.

<NUM>: The SMF node <NUM> may perform a Session Management Policy Establishment procedure to establish a session with the selected PCF node <NUM> and get a default PCC Rules for the session. The SMF node sends a Session Management Policy Establishment Request message Npcf_SMPolicyControl Create Req. to the PCF node.

<NUM>: The PCF node responds with a Session Management Policy Establishment Response message Npcf_SMPolicyControl Create Rsp. to the SMF node to provide service area characteristics to the SMF node. The PCF node may provide policies as per "Service Area". It may also provide any special characteristics of that service Area. For the PDU session, the service area characteristics may include:.

<NUM>: Based on above information, the SMF node <NUM> may update the subscriber services according to the service area characteristics received from the PCF node <NUM> and the Service Area related information for the session received from the AMF node <NUM>. The updating may comprise any one of disabling streaming services, activating LI for the subscriber, blocking some sites, providing sponsor data connectivity, or rejecting the session. For example, in a "Secure Area", e.g. FBI Headquarters, video streaming apps might be disabled. LI for the subscriber might be activated. Or in a School area all pornographic sites are blocked for all users. Further, SMF node may reject the session if it is not able to meet the mandatory requirement of "Service Area". For example, if LI is mandatary for a "Service Area" and the SMF node <NUM> is not able to support that, it may reject the session.

<NUM>: The SMF node <NUM> initiates a UPF selection procedure according to a local configuration. The SMF node <NUM> initiates an N4 Session Establishment procedure with the selected UPF node.

<NUM>: The SMF node <NUM> sends a Namf_Communication_N1N2_msg_Transfer Request message to the AMF node <NUM> including a N1 PDU Session Establishment Accept and N2 PDU Session Resource Setup Request Transfer messages.

<NUM>: The AMF node <NUM> responds a Namf_Communication_N1N2_msg Transfer Response message to the SMF node <NUM>.

<NUM>: The AMF node <NUM> accepts or rejects the session as per the information received from the SMF node <NUM>. The AMF node <NUM> determines accepting or rejecting the session based on the Transfer Request message received from the SMF node.

To summarize, methods performed in a core network <NUM> for dynamically handling access and mobility service areas with different capabilities in a communication system <NUM> are described. The methods may be carried out in an AMF node <NUM>, a UDM node <NUM>, a PCF node <NUM> and a SMF node <NUM>. The UDM node <NUM> may configure Service Area Restriction (SAR) data in a subscription data for a UE <NUM>. The SAR data includes a number of service areas allowed or restricted for the UE and, for each service area, a service area identifier, a service area type and a service area definition. The PCF node may configure a Service Area Definition (SAD) rule for a UE. The SAD rule comprises a service area definition and an indication of a set of service area characteristics enabled in the service area, one or more NSSAI that the service area applies to. The PCF node may receive a Service Area Profile from provisioning system or from NEF and update dynamically SAR based on the received Service Area Profile. The PCF node may create a service area on-demand based on the received Service Area Profile. During a registration procedure, the SAR data and SAD rule may be provided to the AMF node upon request for a UE communication. The AMF node then takes actions for the UE communication based on anyone of the SAR data, the SAD rule and local policies at the AMF node. During a session management procedure, the SMF node <NUM> may receive service area related information with a service area identifier and a service area type from the AMF node, and receive the SAD rule from the PCF node. The SMF node <NUM> then take actions for the UE communication based on the SAD rule, the information received from the AMF node <NUM> and/or local policies at the SMF node.

Therefore, the embodiments herein provide a mechanism to allow flexible definition of access and mobility service areas with different capabilities for e.g. <NUM> systems, for specific network slices, that can also be managed on demand by OTT/Enterprise via NEF service exposure. Few examples of service areas with specific capabilities are.

The embodiments herein allow flexible definition of access and mobility service areas with different capabilities, for specific network slices, for different subscribers based on the different use cases. The embodiments herein also provide new solutions to OTT/AF players to manage the business needs in real-time for use cases such as security, sponsoring and parental control.

Claim 1:
A method for dynamically handling access and mobility service areas with different capabilities in a communication system, the method carried out by an Access and Mobility Management function, AMF, node (<NUM>) and comprising:
Transmitting (<NUM>), to a Unified Data Management, UDM, node (<NUM>), a subscription data request for a user equipment, UE (<NUM>), communication;
Receiving (<NUM>), from the UDM node (<NUM>), subscription data with Service Area Restriction, SAR, data for the UE, wherein the SAR data includes a number of service areas allowed or restricted for the UE and, for each service area, a service area identifier, a service area type, wherein the service area type identifies a service provided in the service area, and a service area definition, wherein the service area definition delimits the service area;
Transmitting (<NUM>), to a Policy Control Function, PCF, node (<NUM>), a policy request for the UE (<NUM>);
Receiving (<NUM>), from the PCF node (<NUM>), a policy response with a Service Area Definition, SAD, rule for the UE (<NUM>), wherein the SAD rule comprises a service area definition and an indication of a set of service area characteristics enabled in the service area, wherein the service area characteristics relate to the service provided in the service area; and
Taking actions (<NUM>) for the UE communication based on anyone of the SAR data, the SAD rule and local policies at the AMF node.