Patent Description:
3GPP TS <NUM> ch5. <NUM> states that when the NF service consumer receives the number of supported packet filter for signaled QoS rules for the PDU session from the UE during the PDU Session Modification procedure after the first inter-system change from EPS to 5GS for a PDU Session established in EPS and transferred from EPS with N26 interface, the NF service consumer shall include the "NUM_OF_PACKET_FILTER" within the "repPolicyCtrlReqTriggers" attribute and the number of supported packet filter for signaled QoS rules within the "numOfPackFilter" attribute. This is only applicable to the interworking scenario as defined in Annex B.

The number of packet filters supported in Long Term Evolution, LTE, is limited to <NUM> per EPS bearer (<NUM> ch10. <NUM>), wherein the number of supported packet filters can reach <NUM> assuming that <NUM> EPS bearers are supported for a PDN connection. The number of packet filters per PDU session can be up to <NUM> in <NUM> (<NUM> ch5. The above chapters from the 3GPP specifications have defined how to handle supported number of packet filters more than the maximum number of supported packet filters in 5GS and after first inter system change from EPS to 5GS in UE and also in SMF as well as PCF.

3GPP TS <NUM> ch6. <NUM> states that at PDU Session Establishment Accept procedure, if interworking with EPS is supported for the PDU session, the SMF shall set in the PDU SESSION ESTABLISHMENT ACCEPT message:.

3GPP TS <NUM> ch9. <NUM> defines the mapped EPS bearer contexts. When the parameter identifier indicates traffic flow template, the length and parameter contents field are coded from octet <NUM> as shown in figure <NUM>. <NUM> and table <NUM>. <NUM> of 3GPP TS <NUM>, which limits the maximum number of packet filters to <NUM> per mapped EPS bearer context.

Document <CIT> discloses ethernet type packet data unit session communications.

There currently exist certain challenge(s). It is not clear how to handle PDU sessions established in 5GS with more packet filters then supported in EPS, for signaled QoS rules during 5GS to EPS mobility procedures. This may result in service disturbance or delay for critical services, such as Delay critical services, MPS etc, during 5GS to EPS inter system change.

PCF may optionally update policy decisions during EPS interworking procedure if certain triggers are provisioned (e. g RAT type change). But there is no trigger that indicates that the supported number of packet filter changed, i.e. the supported number of packet filters is reduced, during 5GS to EPS mobility (e.g. RAT changes may occur within 5GS), and it is not guaranteed that PCF is aware of the change if no applicable policy control report triggers are provisioned before the EPS interworking procedure. Moreover, the RAT type change report to the PCF occurs after the interworking procedure has been triggered, that is, when the UE is already in <NUM> access. Thus service disruption could occur before the PCF can update the PCC Rules according to the packet filter demands
Certain aspects of the disclosure and their embodiments may provide solutions to these or other challenges.

The present disclosure proposes a mechanism regarding how to handle Service Based Architecture, SBA, to Evolved Packets System, EPS, mobility for session established in 5GS with more than a predetermined number of packet filters. That is, with more packet filters that are supported in the EPS domain.

The underlying concept is that the PCF either indicates which packet filters to preserve, or that the PCF indicates some sort of priority for the packet filters. This allows the SMF to determine which packet filters to inactivate or disregard whenever the UE is to be handled in accordance with a fewer number of packet filters.

For example, a new mechanism may be introduced for Policy and Charging Control, PCC, rule provision that the PCF includes an indication for the packet filters of the PCC rule when EPS interworking is applicable.

The first option is that a new attribute, or new attributes, are introduced, one for each packet filter, for indicating whether the corresponding packet filter is to be preserved. Such a new attribute may, for example, be introduced in the FlowInformation to indicate that the packet filters of the Flow Description shall be preserved so that packet filters of the corresponding PCC rule are to be included in Traffic Flow Templates, TFT, of the mapped EPS bearers context.

Another option is that attributes are introduced, one for each packet filter, for indicating the priority of a corresponding packet filter. Such a new attribute may, for example, be introduced in the FlowInformation to indicate the priority of preservation of the corresponding packet filters of the PCC rule for EPS interworking.

Yet another option is to introduce a new attribute in the PCC rule for indicating the priority of preservation, or preservation indication, for all packets filters in that corresponding PCC rule for EPS interworking.

An even further option is to reuse the PCC rule precedence to indicate the priority of the preservation of the packet filters of the PCC rule for EPS interworking.

Yet another option is that the SMF may make its own decision on whether or not to allocate packets filters based on local policy, for example based on operator policy or implementation. It is noted that this option may, or mar not, override the information received above from the PCF.

It is noted that a PCC rule may be considered a set of information elements enabling the detection of a service data flow and providing parameters for policy control and/or charging control. There may be two different types of PCC rules as defined in 3GPP TS <NUM>.

The first type is related to dynamic PCC rules. These type of PCC rules may be dynamically provisioned by the PCF to the SMF. These PCC rules may be either predefined or dynamically generated in the PCF. Dynamic PCC rules may be installed, modified and removed at any time.

The second type is related to predefined PCC rules. These type of PCC rules may be preconfigured in the SMF. Predefined PCC rules may be activated or deactivated by the PCF at any time. Predefined PCC rules within the PCF may be grouped allowing the PCF to dynamically activate a set of PCC rules.

It is noted that the SMF may decide to use the information received from the PCF to decide which of the packets filters to allocate, irrespective of whether these packets filters are associated to the dynamic or predefined PCC rules.

On top of the above, it is noted that the PCF may include, or activate, the above described new attribute in the PCC rule only in case it is aware that there might be a situation in which said SBA network is interworking with an Evolved Packet System, EPS, network, for a particular UE.

The PCF may become aware of this particular aspect based on, for example, the Data Network Name, DNN, or the Single Network Slice Selection Assistance Information, S-NSSAI, that is received by the PCF during the random access procedure of the UE to the <NUM> network.

The S-NSSAI is an identifier for a Network Slice across the <NUM> core network, the <NUM>-RAN and the UE. The S-NSSAI may be associated with a PLMN, for example PLMN ID, and may have network-specific values or have standard values. An S-NSSAI may be used by the UE in access network in the PLMN that the S-NSSAI is associated with.

In a telecommunication network, Data Networks may be identified using a DNN. The DNN is typically in the form of an Access Point Name, APN, or the like. In <NUM>, the Data Network Name, DNN, may be equivalent to an APN in EPS.

In a detailed example, the inventors have found that it might be beneficial if the SMF provides a policy update to the PCF indicating that one or more PCC rules, or one or more packet filters, are invalid after 5GS to EPS mobility due to the reasons that either all packet filters in the PCC rule are removed, i.e. the rule is inactive, or that the number of supported packet filters in the EPS network are exceeded.

In a further example, the SMF may provide a policy control message at 5GS to EPS mobility to indicate that the supported maximum number of packet filters has been reduced. This could be done by reusing the existing policy control request trigger, i.e. NUM_OF_PACKET_FILTER. For a PDU session established in 5GS or established in EPS but for which an inter-system change from EPS to 5GS occurred in the past, with more than the maximum number of supported packet filters for signaled QoS rules, after 5GS to EPS mobility, the SMF may report policy control request trigger NUM_OF_PACKET_FILTER and may set the number of supported packet filters to <NUM> per EPS bearer, or <NUM> per PDN connection assuming that <NUM> EPS bearers are supported for a single PDN connection. Another option is to introduce a new policy control request trigger NO_NUM_OF_PACKET_FILTER. For a PDU session established in 5GS or established in EPS but for which an inter-system change from EPS to 5GS occurred in the past with more than the maximum number of packet filters for signaled QoS rules, after 5GS to EPS mobility, the SMF may report policy control request trigger NO_NUM_OF_PACKET_FILTER. When the PCF receives such a trigger report, it may imply that the supported maximum number of packet filters is <NUM> per PDN connection. In the above, the number of <NUM> is explicitly mentioned as that may be implemented in conventional EPS systems, i.e. <NUM> packet filters per EPS bearer and <NUM> EPS bearers per PDN connection. However, any number lower than the number supported by 5GS may be applicable.

In a further detailed example a failure code may be introduced, for example for indicating that a PCC rule can't be installed or updated due to the situation that the number of packet filters have exceeded the maximum number of supported packet filters for a PDU session.

Certain embodiments may provide one or more of the following technical advantage(s). The present disclosure provides guidance to the SMF to determine which packet filters to maintain at inter system change from 5GS to EPS. This helps to avoid service disturbance or delay that may be caused by no being able to transfer all packet filters of installed PCC rules to the corresponding EPS bearer due to the limitation of the maximum number of packet filters per PDN connection in EPS.

Another advantage of the present disclosure is that it may make the PCF aware of removed, or inactivated, PCC rules due to the fact that none of the packet filters of the corresponding PCC rule can be transferred to an EPS bearer context for the scenario that in 5GS PDU session established with the number of packet filters for signaled QOS rules is more than a predetermined number of packet filters, for example sixteen packet filters. A PCC rule error report with an explicit failure code may be generated to indicate the removal, or inactivation, of a PCC rule due to the situation that the number of packet filters exceed the maximum number of packet filters allowed in EPS, after the 5GS to EPS mobility. The PCF is then aware of the situation and can make proper policy decisions as a result thereof.

With respect to the above, it is noted that the PCC rules may not necessarily be removed or inactivated. The PCC rules may still be kept active, but may be marked by any means possible. The SMF may then inform the PCF with respect to the marked PCC rules, irrespective of whether the PCC rules have been removed, inactivated or kept active.

Yet an additional benefit of the invention is that the SMF may proactively notify the PCF about the change in supported number of packets filters after the 5GS to EPS mobility such that the PCF is able to make proper policy decisions thereafter based on the updated number of supported packet filters.

Embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art. Additional information may also be found in the document(s) provided in the Appendix.

Figure QQ1 shows an example of a communication system QQ100 in accordance with some embodiments.

In the example, the communication system QQ100 includes a telecommunication network QQ102 that includes an access network QQ104, such as a radio access network (RAN), and a core network QQ106, which includes one or more core network nodes QQ108. The access network QQ104 includes one or more access network nodes, such as network nodes QQ110a and QQ110b (one or more of which may be generally referred to as network nodes QQ110), or any other similar <NUM>rd Generation Partnership Project (3GPP) access node or non-3GPP access point. The network nodes QQ110 facilitate direct or indirect connection of user equipment (UE), such as by connecting UEs QQ112a, QQ112b, QQ112c, and QQ112d (one or more of which may be generally referred to as UEs QQ112) to the core network QQ106 over one or more wireless connections.

Moreover, in different embodiments, the communication system QQ100 may include any number of wired or wireless networks, network nodes, UEs, and/or any other components or systems that may facilitate or participate in the communication of data and/or signals whether via wired or wireless connections. The communication system QQ100 may include and/or interface with any type of communication, telecommunication, data, cellular, radio network, and/or other similar type of system.

The UEs QQ112 may be any of a wide variety of communication devices, including wireless devices arranged, configured, and/or operable to communicate wirelessly with the network nodes QQ110 and other communication devices. Similarly, the network nodes QQ110 are arranged, capable, configured, and/or operable to communicate directly or indirectly with the UEs QQ112 and/or with other network nodes or equipment in the telecommunication network QQ102 to enable and/or provide network access, such as wireless network access, and/or to perform other functions, such as administration in the telecommunication network QQ102.

In the depicted example, the core network QQ106 connects the network nodes QQ110 to one or more hosts, such as host QQ116. The core network QQ106 includes one more core network nodes (e.g., core network node QQ108) that are structured with hardware and software components. Features of these components may be substantially similar to those described with respect to the UEs, network nodes, and/or hosts, such that the descriptions thereof are generally applicable to the corresponding components of the core network node QQ108.

The host QQ116 may be under the ownership or control of a service provider other than an operator or provider of the access network QQ104 and/or the telecommunication network QQ102, and may be operated by the service provider or on behalf of the service provider. The host QQ116 may host a variety of applications to provide one or more service.

As a whole, the communication system QQ100 of Figure QQ1 enables connectivity between the UEs, network nodes, and hosts.

In some examples, the telecommunication network QQ102 is a cellular network that implements 3GPP standardized features. Accordingly, the telecommunications network QQ102 may support network slicing to provide different logical networks to different devices that are connected to the telecommunication network QQ102. For example, the telecommunications network QQ102 may provide Ultra Reliable Low Latency Communication (URLLC) services to some UEs, while providing Enhanced Mobile Broadband (eMBB) services to other UEs, and/or Massive Machine Type Communication (mMTC)/Massive IoT services to yet further UEs.

In some examples, the UEs QQ112 are configured to transmit and/or receive information without direct human interaction. For instance, a UE may be designed to transmit information to the access network QQ104 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the access network QQ104. Additionally, a UE may be configured for operating in single- or multi-RAT or multi-standard mode. For example, a UE may operate with any one or combination of Wi-Fi, NR (New Radio) and LTE, i.e. being configured for multi-radio dual connectivity (MR-DC), such as E-UTRAN (Evolved-UMTS Terrestrial Radio Access Network) New Radio - Dual Connectivity (EN-DC).

In the example, the hub QQ114 communicates with the access network QQ104 to facilitate indirect communication between one or more UEs (e.g., UE QQ112c and/or QQ112d) and network nodes (e.g., network node QQ110b). In some examples, the hub QQ114 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs. For example, the hub QQ114 may be a broadband router enabling access to the core network QQ106 for the UEs. As another example, the hub QQ114 may be a controller that sends commands or instructions to one or more actuators in the UEs. Commands or instructions may be received from the UEs, network nodes QQ110, or by executable code, script, process, or other instructions in the hub QQ114. As another example, the hub QQ114 may be a data collector that acts as temporary storage for UE data and, in some embodiments, may perform analysis or other processing of the data. As another example, the hub QQ114 may be a content source. For example, for a UE that is a VR headset, display, loudspeaker or other media delivery device, the hub QQ114 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which the hub QQ114 then provides to the UE either directly, after performing local processing, and/or after adding additional local content. In still another example, the hub QQ114 acts as a proxy server or orchestrator for the UEs, in particular in if one or more of the UEs are low energy IoT devices.

The hub QQ114 may have a constant/persistent or intermittent connection to the network node QQ110b. The hub QQ114 may also allow for a different communication scheme and/or schedule between the hub QQ114 and UEs (e.g., UE QQ112c and/or QQ112d), and between the hub QQ114 and the core network QQ106. In other examples, the hub QQ114 is connected to the core network QQ106 and/or one or more UEs via a wired connection. Moreover, the hub QQ114 may be configured to connect to an M2M service provider over the access network QQ104 and/or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with the network nodes QQ110 while still connected via the hub QQ114 via a wired or wireless connection. In some embodiments, the hub QQ114 may be a dedicated hub - that is, a hub whose primary function is to route communications to/from the UEs from/to the network node QQ110b. In other embodiments, the hub QQ114 may be a non-dedicated hub - that is, a device which is capable of operating to route communications between the UEs and network node QQ110b, but which is additionally capable of operating as a communication start and/or end point for certain data channels.

Figure QQ6 shows a communication diagram of a host QQ602 communicating via a network node QQ604 with a UE QQ606 over a partially wireless connection in accordance with some embodiments. Example implementations, in accordance with various embodiments, of the UE (such as a UE QQ112a of Figure QQ1 and/or UE QQ200 of Figure QQ2), network node (such as network node QQ110a of Figure QQ1 and/or network node QQ300 of Figure QQ3), and host (such as host QQ116 of Figure QQ1 and/or host QQ400 of Figure QQ4) discussed in the preceding paragraphs will now be described with reference to Figure QQ6.

Like host QQ400, embodiments of host QQ602 include hardware, such as a communication interface, processing circuitry, and memory. The host QQ602 also includes software, which is stored in or accessible by the host QQ602 and executable by the processing circuitry. The software includes a host application that may be operable to provide a service to a remote user, such as the UE QQ606 connecting via an over-the-top (OTT) connection QQ650 extending between the UE QQ606 and host QQ602. In providing the service to the remote user, a host application may provide user data which is transmitted using the OTT connection QQ650.

The network node QQ604 includes hardware enabling it to communicate with the host QQ602 and UE QQ606. The connection QQ660 may be direct or pass through a core network (like core network QQ106 of Figure QQ1) and/or one or more other intermediate networks, such as one or more public, private, or hosted networks.

The UE QQ606 includes hardware and software, which is stored in or accessible by UE QQ606 and executable by the UE's processing circuitry. The software includes a client application, such as a web browser or operator-specific "app" that may be operable to provide a service to a human or non-human user via UE QQ606 with the support of the host QQ602. In the host QQ602, an executing host application may communicate with the executing client application via the OTT connection QQ650 terminating at the UE QQ606 and host QQ602. The OTT connection QQ650 may transfer both the request data and the user data. The UE's client application may interact with the user to generate the user data that it provides to the host application through the OTT connection QQ650.

The OTT connection QQ650 may extend via a connection QQ660 between the host QQ602 and the network node QQ604 and via a wireless connection QQ670 between the network node QQ604 and the UE QQ606 to provide the connection between the host QQ602 and the UE QQ606. The connection QQ660 and wireless connection QQ670, over which the OTT connection QQ650 may be provided, have been drawn abstractly to illustrate the communication between the host QQ602 and the UE QQ606 via the network node QQ604, without explicit reference to any intermediary devices and the precise routing of messages via these devices.

As an example of transmitting data via the OTT connection QQ650, in step QQ608, the host QQ602 provides user data, which may be performed by executing a host application. In some embodiments, the user data is associated with a particular human user interacting with the UE QQ606. In other embodiments, the user data is associated with a UE QQ606 that shares data with the host QQ602 without explicit human interaction. In step QQ610, the host QQ602 initiates a transmission carrying the user data towards the UE QQ606. The host QQ602 may initiate the transmission responsive to a request transmitted by the UE QQ606. The request may be caused by human interaction with the UE QQ606 or by operation of the client application executing on the UE QQ606. The transmission may pass via the network node QQ604, in accordance with the teachings of the embodiments described throughout this disclosure. Accordingly, in step QQ612, the network node QQ604 transmits to the UE QQ606 the user data that was carried in the transmission that the host QQ602 initiated, in accordance with the teachings of the embodiments described throughout this disclosure. In step QQ614, the UE QQ606 receives the user data carried in the transmission, which may be performed by a client application executed on the UE QQ606 associated with the host application executed by the host QQ602.

In some examples, the UE QQ606 executes a client application which provides user data to the host QQ602. The user data may be provided in reaction or response to the data received from the host QQ602. Accordingly, in step QQ616, the UE QQ606 may provide user data, which may be performed by executing the client application. In providing the user data, the client application may further consider user input received from the user via an input/output interface of the UE QQ606. Regardless of the specific manner in which the user data was provided, the UE QQ606 initiates, in step QQ618, transmission of the user data towards the host QQ602 via the network node QQ604. In step QQ620, in accordance with the teachings of the embodiments described throughout this disclosure, the network node QQ604 receives user data from the UE QQ606 and initiates transmission of the received user data towards the host QQ602. In step QQ622, the host QQ602 receives the user data carried in the transmission initiated by the UE QQ606.

In an example scenario, factory status information may be collected and analyzed by the host QQ602. As another example, the host QQ602 may process audio and video data which may have been retrieved from a UE for use in creating maps. As another example, the host QQ602 may collect and analyze real-time data to assist in controlling vehicle congestion (e.g., controlling traffic lights). As another example, the host QQ602 may store surveillance video uploaded by a UE. As another example, the host QQ602 may store or control access to media content such as video, audio, VR or AR which it can broadcast, multicast or unicast to UEs. As other examples, the host QQ602 may be used for energy pricing, remote control of non-time critical electrical load to balance power generation needs, location services, presentation services (such as compiling diagrams etc. from data collected from remote devices), or any other function of collecting, retrieving, storing, analyzing and/or transmitting data.

In some examples, a measurement procedure may be provided for the purpose of monitoring data rate, latency and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring the OTT connection QQ650 between the host QQ602 and UE QQ606, in response to variations in the measurement results. The measurement procedure and/or the network functionality for reconfiguring the OTT connection may be implemented in software and hardware of the host QQ602 and/or UE QQ606. In some embodiments, sensors (not shown) may be deployed in or in association with other devices through which the OTT connection QQ650 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or supplying values of other physical quantities from which software may compute or estimate the monitored quantities. The reconfiguring of the OTT connection QQ650 may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not directly alter the operation of the network node QQ604. In certain embodiments, measurements may involve proprietary UE signaling that facilitates measurements of throughput, propagation times, latency and the like, by the host QQ602. The measurements may be implemented in that software causes messages to be transmitted, in particular empty or 'dummy' messages, using the OTT connection QQ650 while monitoring propagation times, errors, etc..

Figure QQ7 shows an example of a flow chart in accordance with the present disclosure.

It is noted that, in accordance with the present disclosure, the SMF may have so-called Packet Data Network, PDN, Gateway Control plane, PGW-C functionality embedded therein. The PGW-C controls the functionality performed by an assigned PGW-U when control and user plane separation is in place. When a subscriber establishes an EPS bearer to a given PDN, the PGW-C selects and controls the point of attachment to that PDN for the life of the EPS bearer. Responsibilities include resource management for bearer resources, bearer binding, subscriber IP address management and mobility support. The use of SMF having PGW-C functionality, allows the policy control and charging rules function, PCRF, used for policy control in the Evolved Packet Core, EPC, to be replaced by a new dual-mode policy management system that supports <NUM>-enabled devices regardless of the access technology currently used.

The flow chart is directed to a method performed by a session management function, SMF, in a service based architecture, SBA, network for handling packet filters when said SBA network is interworking with an Evolved Packet System, EPS, network, wherein the number of supported packet filters in the SBA network exceeds the number of supported packet filters in the EPS network, the method comprising the steps of:.

The above is described in more detail here below.

A User Equipment, UE, QQ701 may initiate the procedure by requesting a PDU Session Establishment QQ709 in 5GS. The UE may initiate the UE Requested PDU Session Establishment procedure by the transmission of a NAS message containing a PDU Session Establishment Request within the N1 SM container. The PDU Session Establishment Request may include a PDU session ID, Requested PDU Session Type, a Requested SSC mode, 5GSM Capability, PCO, SM PDU DN Request Container, Number Of Packet Filters, Header Compression Configuration, UE Integrity Protection Maximum Data Rate, Always-on PDU Session Requested, RSN and [PDU Session Pair ID. The present disclosure is directed to the number of Packet Filters.

The Number Of Packet Filters may indicate the number of supported packet filters for signaled QoS rules for the PDU Session that is being established. The number of packet filters indicated by the UE may be valid for the lifetime of the PDU Session.

For example, the UE may indicate the maximum number of packet filters that can be supported for the PDU session in a maximum number of packet filter Information Element, IE, of a PDU session establishment request message only if the UE is able to support more than the maximum number of packet filters in EPS, for this PDU session. In this regard, it is noted that, typically, the maximum number of packet filters is <NUM> per EPS bearer, wherein typically <NUM> EPS bearers are supported for a PDN connection established in an Evolved Packet System, EPS, network (<NUM>). This may result in a maximum number of <NUM> packet filters in EPS.

Following the above, it is noted that the present disclosure is also applicable for a PDU Session Modification procedure instead of a PDU Session Establishment procedure, for the situation in which an EPS to 5GS handover occurs. In that particular scenario, the UE notifies, in the PDU Session Modification request, the <NUM> network that is supports more than the maximum number of packet filters supported by EPS.

The above described message is sent to the Access and Mobility Management Function, AMF, QQ705. One of the responsibilities of the AMF QQ705 is related to registration management. Registration management allows a UE QQ701 to register and deregister with the <NUM> network.

In a next step QQ710, the AMF QQ705 may send a PDU Session Create Context request towards a Session Management Function, SMF, QQ707. The PDU Session Create Context request is, for example, the Nsmf_PDUSession_CreateSmContext Request and it may include the PDU Session Establishment Request that was initially sent by the UE QQ701. One of the responsibilities of the SMF is managing the PDU sessions of a UE, for example creating, updating and removing Protocol Data Unit, PDU, sessions and managing session context with the User Plane Function, UPF.

The SMF QQ707 may then transmit, to a Policy Control Function, PCF, QQ708 in said <NUM> network, a policy control request in relation to the session request of the UE QQ701. The policy control request is, for example, an Npcf_SMPolicyControl_Create Request or an Npcf_SMPolicyControl_Update Request.

The Policy Control Service may perform provisioning, update and removal of session related policies and PCC rules by the Policy Control Function, PCF, QQ708 to the NF service consumer, for example the SMF QQ707. The Policy Control Service can be used for charging control, policy control and/or application detection and control. Session Management Policy Control Service applies to the cases where the SMF QQ707 interacts with the PCF QQ708 in a non-roaming scenario, the Visited SMF interacts with the Visited PCF in the local breakout roaming scenario and the Home SMF interacts with the Home PCF in the home-routed scenario.

Based on the received policy control request, the PCF QQ708 may transmit a policy control response QQ712 back to the SMF QQ707. The policy control response is, for example, an Npcf_SMPolicyControl_Create Response or an Npcf_SMPolicyControl_Update Response. Such a response includes Policy Decisions. The present disclosure is directed to the concept that the response comprises additional packet filter information, which additional packet filter information indicates to the SMF QQ707 how to deal with an excess number of packet filters in <NUM>-<NUM> interworking scenarios. That is, it provides information to the SMF QQ707 which packet filters to "keep" and which packet filters to disregard in order to reduce the total number of packet filters back to the number that is allowed in the EPS network, for example <NUM> packet filters per EPS bearer. This is explained in a bit more detail here below.

The additional packet filter information may, for example, include any of preservation information which indicates which applicable packet filters to preserve when said SBA (<NUM>) network is interworking the EPS network and/or priority information which indicates priority information of the applicable packet filters that is to be taken into account when determining which applicable packet filters to preserve when the SBA (<NUM>) network is interworking with the EPS network.

It is noted that the PCF may determine that the SBA network is interworking with an Evolved Packet System, EPS, network based on, for example, the Data Network Name, DNN, or the Single Network Slice Selection Assistance Information, S-NSSAI, that is received by the PCF, for example during the random access procedure of the UE to the <NUM> network.

In an example, the preservation information may be included as an attribute in the FlowInformation, for example as shown below.

The PCF QQ708 may, for example, ensure that for all the dynamic PCC rules of a PDU session, the number of preserved packet filters contained within the "flowDescription" attribute or the "ethFlowDescripiont" attribute with the "packetFilterUsage" set to true does not exceed the value of supported by EPS, for example <NUM> per EPS bearer or <NUM> in total considering <NUM> EPS bearers.

In an example, the priority information may be included as an attribute in the FlowInformation, for example as shown below.

The SMF QQ707 may, for example, use the "packFiltPrio" attribute in order to prioritize the packet filters to be preserved from those provisioned for all the dynamic PCC rules of a PDU session. Only the packet filters with higher priority are preserved. The higher the value of the packFiltPrio attribute, the lower the precedence of the packet filter.

In a further example, the preservation information may be included as an attribute in the definition of the PCC rule, for example as shown below.

The "packFiltPre" attribute may be used to specify the precedence of the packet filters of the PCC rule among packet filters of all PCC rules associated with the PDU session for EPS interworking. It may, for example, include an integer value in the range from <NUM> to <NUM> (decimal). The higher the value of the "packFiltPre" attribute, the lower the precedence of packet filters of that PCC rule is.

Alternatively, the PCC rule could include a flag, which would indicate whether the PCC rule should be preserved at EPS interworking. This may, for example, be accomplished by using an attribute called packFiltPrsv which may be of a Boolean type. If present and set to TRUE, the packet filter(s) of the corresponding PCC rule may be preserved at EPS interworking procedures, i.e. the packet filter(s) may be included in the Traffic Flow Template, TFT, of the mapped EPS bearer contexts. The default value FALSE may apply if the attribute is not present and/or has not been supplied previously.

The preservation information may also be directed to reusing the "precedence" of the PCC rule to determine the order in which packet filters of the PCC rule is applied relative to the packet filters of other PCC rules within the same PDU session for EPS interworking, or reusing the "precedence" of the PCC rule to determine whether the PCC rule should be preserved at EPS interworking.

During the step Validating, as indicated with reference numeral QQ713, the SMF QQ707 may determine whether the number of packet filters received from the PCF QQ708 can be supported. The SMF QQ707 may report a failure, i.e. a PCC Rule failure, back to the PCF QQ708 in case the validating fails. The validation step may include validating that the total number of packet filters of the PDU session does not exceed the received Number of Packet Filter as initially received from the UE QQ701 in the PDU Session Establishment or Modification Request message. The validation may also, or alternatively, be directed to validate that the total number of preserved packet filters of the PDU session has reached the maximum number of packet filter preservations for EPS interworking. This is explained in more detail here below.

Multiple failure codes may be applicable and may be transmitted QQ714 back to the PCF QQ708, as shown in the table here below. It is noted that the first two failure codes may be transmitted as a result of the validating step as indicated by reference numeral QQ713. The third failure code here below may be transmitted as a result of the step as indicated with reference numeral QQ718.

It is noted that the first indicated failure code, i.e. directed to the concept that the number of packet filters exceeds the number as initially indicated by the UE in the corresponding PDU Session Establishment request is not a failure code that is specifically directed to an EPS interworking scenario.

That is, this particular scenario may be directed to a method performed by a Session Management Function, SMF, in a Service Based Architecture, SBA, network for handling packet filters related to a session of User Equipment, UE, in said SBA network, the method comprising the steps of transmitting, by said SMF, to a Policy Control Function, PCF, in said SBA network, a policy control request in relation to said session of said UE with said SBA network and receiving, by said SMF, from said PCF, a policy control response, wherein said policy control response comprises applicable packet filters for said session request of said UE with said SBA network, and determining, by said SMF, that the number of packet filter received from the PCF exceeds a number of packet filters supported by the UE, and transmitting, by said SMF, to said PCF, a failure code, i.e. a PCC rule report failure code, indicating that one or more packet filters could not be installed or updated due to the reason that the maximum number of packet filters has been reached. It is noted that, in this regard, the number of packet filters supported by the UE may be communicated in the originating PDU Session Establishment Request message as indicated above or, alternatively, in a PDU Session Modification Request message. The above is explained in more detail with respect to figure QQ8.

Based on the received failure code, the PCF QQ708 may then determine new policy decisions and may provide these back to the SMF QQ707, as indicated by the reference numeral QQ715.

In addition to the above, the procedure may continue QQ716 in the PDU Session Establishment procedure, wherein the SMF QQ707 may take into account the PCC rule's packet filter preservation indication when handling the Traffic Flow Template, TFT, of mapped EPS bearer contexts.

At a certain moment in time, a 5GS to EPS handover or Idle mobility procedure may be triggered from the UE QQ701, as indicated with the reference numeral QQ717. This may trigger the SMF QQ707 to mark PCC rule(s) that are to be deactivated or being kept active, as indicated with reference numeral QQ718. The PCC rules for which none of its corresponding packet filters are to be preserved for 5GS to EPS interworking may be marked as to become deactivated or kept being active. This example is directed to this third failure code as disclosed in the table here above, i.e. PACKET_FILTER_NOT_PRESERVED.

It is noted that the SMF QQ707 may decide which whether or not to allocate packet filters based on operator policy or implementation. The SMF QQ707 may then, subsequently, inform the PCF about its decision.

In addition to the above, the SMF QQ707 may update or notify QQ719 the PCF QQ708 with respect to the updated maximum number of packet filters. For example, the SMF QQ707 may send an SMPolicyControl _Update Request to the PCF which includes Policy Control Report Triger "NO_NUM_OF_PACKE_FILTER" indicating that the number of packet filter per PDN connection has changed, i.e. is reduced to the number of packet filters supported by EPS. The maximum number of supported packets filters in EPS may be <NUM> per EPS bearer, wherein up to <NUM> EPS bearers are supported per PDN connection. In addition, a PCC rule report may be provided with a failureCode set to PACKET_FILTER_NOT_PRESERVED, if applicable. In another example, the SMF may send an SMPolicyControl_Update Request to PCF includes Policy Control Report Triger "NUM_OF_PACKE_FILTER" and set "numPaketFilter" equal to <NUM>, or <NUM>, indicating that number of packet filters per EPS bearer has changed to <NUM> or indicating that the number of packet filters per PDN connection has changed to <NUM>, respectively. In addition, a PCC rule report may be provided with a failureCode set to PACKET_FILTER_NOT_PRESERVED, if applicable.

The PCF QQ708 may respond with an SMPolicyControl _Update Response and may include new policy decisions, if necessary. This is indicated with reference numeral QQ720. The procedure may then continue to finish 5GS to EPS handover or Idle Mobility steps QQ721. In addition, An SMF triggered PDU Session Modification may be initiated resulted from the step QQ720, which is indicated with reference numeral QQ722.

Figure QQ8 discloses an example of how a Session Management Function, SMF QQ707, will tackle a situation in which the number of packet filters provided by the Policy Control Function, PCF, QQ708 exceeds the number of supported packet filters initially indicated by the UE QQ701.

The present disclosure is directed to a new mechanism for the SMF QQ707 to generate a PCC rule failure report when the number of packet filters for all signaled QOS rules exceed the maximum number of UE supported packet filters, during PCC rule provision, so that the PCF is able to adapt policy decisions accordingly.

The underlying concept is that the SMF QQ707 introduced a failureCode for a PCC rule error report in SBA networks, like the 5GS, that the corresponding PCC rule can not be installed or updated due to the reasons that the maximum number of packets filters of all signaled QoS rules of the corresponding PDU session of the UE has been reached.

Figure QQ8 discloses an example in which a User Equipment, UE, QQ701 sends a PDU Session Establishment request procedure for establishing a PDU session with the SBA network, as indicated with reference numeral QQ804, and shows an example in which a UE QQ701 sends a PDU Session Modification request procedure for modifying an ongoing PDU session with the SBA network, as indicated with reference numeral QQ805.

With respect to the PDU Session Establishment procedure QQ804, a PDU Session Establishment Request message may be send QQ801 to the AMF QQ705 via the NGRAN QQ703, like the gNodeb. Such a request message comprises an indication of the number of packet filters that are supported by the UE QQ701.

The UE QQ701 may thus initiate the UE Requested PDU Session Establishment procedure QQ804 by the transmission of a NAS message containing a PDU Session Establishment Request within the N1 SM container. The PDU Session Establishment Request includes a PDU session ID, Requested PDU Session Type, a Requested SSC mode, 5GSM Capability, PCO, SM PDU DN Request Container, [Number Of Packet Filters], [Header Compression Configuration], UE Integrity Protection Maximum Data Rate, [Always-on PDU Session Requested], [RSN] and [PDU Session Pair ID]. The present disclosure is directed to the [Number of Packet Filters] attribute.

The AMF QQ705 may then select an SMF QQ707 as described in clause <NUM>. <NUM> of TS <NUM> and clause <NUM>. If the Request Type indicates "Initial request" or the request is due to handover from EPS or from non-3GPP access serving by a different AMF, the AMF QQ705 may store an association of the S-NSSAI(s), the DNN, the PDU Session ID, the SMF ID as well as the Access Type of the PDU Session.

If the AMF QQ705 does not have an association with an SMF QQ707 for the PDU Session ID provided by the UE QQ701, for example when Request Type indicates "initial request", the AMF QQ705 may invoke the Nsmf_PDUSession_CreateSMContext Request QQ802, but if the AMF QQ705 already has an association with an SMF QQ707 for the PDU Session ID provided by the U QQ701, for example when Request Type indicates "existing PDU Session", the AMF QQ705 may invoke the Nsmf_PDUSession_UpdateSMContext Request QQ807 as is the case for the PDU Session Modification request procedure QQ805.

It is noted that the PDU Session Request procedure QQ801 may comprise additional steps which are not shown in the figures for readability purposes. The SMF QQ701 may, for example, contact a UDM, for subscription retrieval or anything alike.

The present disclosure focuses on different steps in the procedure. For example, if dynamic PCC rules are to be used for the PDU session, the SMF QQ707 may perform PCF selection. If the initial Request Type indicates "Existing PDU Session" or "Existing Emergency PDU Session", like is the case for the PDU Modification Request procedure QQ805, the SMF may use the PCF that was already selected for that particular PDU session.

In any case, the SMF QQ707 may perform an SMPolicyControl request procedure, for example an SMPolicyControl_Create request or an SMPolicyControl _Update request as indicated with the reference numerals QQ803 and QQ808. The idea is to establish, or update, an SM Policy Association with the PCF and to get the PCC rules for the corresponding PDU Session. These requests may comprise an indication to the number of Packet Filters supported by the UE QQ701, for example using an attribute NumOfPackFilter.

The PCF QQ708 responds QQ809 by providing a SMPolicyControl_Create response or SMPolicyControl _Update response message indicating the policy decisions, including the number of packet filters of signaled QoS rules of the PDU session.

The present disclosure is directed to a step that is performed by the SMF QQ707 trigged by the above described response message. That is, the SMF QQ707 validates QQ810 that the number of packet filters of the signaled QoS rules of the PDU session does not exceed the initially provided number of Packet Filters supported by the UE QQ701. If the validation fails, i.e. if the number of packet filter of the signaled QoS rules of the PDU session does exceed the initially provided number of Packet Filters supported by the UE QQ701, the SMF may provide an indication that such a failure has occurred.

This may, for example, be reported in that PCC rules are set as inactive with a failureCode set to "MAX_NR_PACKET_FILTERS_EXCEEDED". This may be reported as indicated by the reference numeral QQ811, for example as shown in the table below.

Finally, the PCF QQ708 may respond with adjusted policy decisions, as indicated with reference numeral QQ812 and the PDU Session Establishment procedure QQ804 or the PDU Session Modification procedure QQ805 may continue QQ813.

One of the advantages of the above described procedure is that in case the number of packet filters of all signaled QoS rules has reached the maximum number of supported packet filters indicated by the UE QQ701, the SMF QQ707 can generate a PCC rule error report with the specific failure code, so that the PCF QQ708 is aware of the situation and can adjust the policy decision accordingly.

Particularly, if the PCF provides new or modified PCC rules to the SMF and if the number of packet filters for the provided PCC rules exceeds the value included within the "numOfPackFilter" attribute, the SMF may reject the installation of the affected PCC rules based on operator policies until the limit is reached and include a "ruleReports" attribute containing a RuleReport data instance which specifies the affected PCC rules within the "pccRuleIds" attribute, the status of the PCC rule as "INACTIVE" as the value within the "ruleStatus" attribute and the "MAX_NR_PACKET_FILTERS_EXCEEDED" as the value of the "failureCode" attribute.

Further, when the UE establishes a PDN connection through the 5GS network in an 5GS-EPC interworking deployment, and if the feature "FilterPreservation" is supported, the PCF may provide, as part of the PCCRule data type(s) for the PCC Rules to be installed, the "packFiltPrsv" attribute to indicate that the packet filters should be preserved when the UE moves to the EPC network. The PCF can ensure that, for all the dynamic PCC rules of the PDU session, the number of preserved packet filters contained within the "flowDescription" attribute or the "ethFlowDescription" attribute with the "packetFilterUsage" set to true does not exceed the value of the maximum number of supported packet filters in EPS. If the number of packet filters for PCC Rules that include the"packFiltPrsv" attribute set to true exceeds the this value, the SMF+PGW-C based on operator policies may:.

Further, when the UE has an established PDN connection through the 5GS network in an 5GS-EPC interworking deployment, if the feature "FilterPreservation" is supported, the PCF may provide, as part of the PccRule data type for the PCC Rules to be installed/modified, the "packFiltPrsv" attribute to indicate that the packet filters should be preserved when the UE moves to the EPC network. The PCF shall ensure that, for all the dynamic PCC rules of the PDU session, the number of preserved packet filters contained within the "flowDescription" attribute or the "ethFlowDescription" attribute with the "packetFilterUsage" set to true does not exceed the value maximum number of supported packet filters in EPS. If the PCF provides new/modified PCC Rules and the final number of installed packet filters for PCC Rules that include the"packFiltPrsv" attribute exceeds the value of the maximum number of supported packet filters in EPS, the SMF+PGW-C based on operator policies may:.

Further, when the UE handed over from 5GS to EPC/E-UTRAN and if the feature "FilterPreservation" is supported, the SMF+PGW-C may send an HTTP POST request to the PCF as follows:.

Claim 1:
A method performed by a session management function, SMF, in a service based architecture, SBA, network for handling packet filters related to a session of User Equipment, UE, in said SBA network, the method comprising the steps of:
- transmitting, by said SMF, to a Policy Control Function, PCF, in said SBA network, a policy control request in relation to said session of said UE with said SBA network;
- receiving, by said SMF, from said PCF, a policy control response, wherein said policy control response comprises applicable packet filters for said session of said UE with said SBA network,
- determining, by said SMF, that a number of the applicable packet filters received from said PCF exceeds a number of packet filters supported by said UE;
- transmitting, by said SMF, to said PCF, an update message with rule report comprising a failure code indicating that at least one of said applicable packet filters cannot be installed or updated due to that a maximum number of packet filters has been reached.