Support for priority of SMS over IMS

Abstract

Systems and methods are disclosed for supporting multimedia priority service (MPS) for messaging over Internet Protocol (IP) Multimedia Subsystem (IMS). In one embodiment, a method performed by a proxy call session control function (P-CSCF) for on-demand MPS for messaging includes receiving a notification from a serving call session control function (S-CSCF) indicating that MPS messaging is activated for a user equipment (UE) or subscriber. The method also includes receiving a session initiation protocol (SIP) message from the UE, and inserting a resource priority header into the SIP message that causes the SIP message to be handled in accordance with the MPS message being activated for the UE or subscriber. In this way, support for MPS messaging over IMS is provided.

Description

[0001] Related applications

[0002] This application claims the benefit of provisional patent application 63 / 556,110, filed on February 21, 2024, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] This disclosure relates to Multimedia Priority Service (MPS) over Internet Protocol (IP) Multimedia Subsystem (IMS), and more specifically, to MPS for message delivery over IMS. Background Technology

[0004] Multimedia Priority Service (MPS) is an existing feature that enables subscribers with this feature to receive priority when initiating Internet Protocol (IP) Multimedia Subsystem (IMS) sessions. Subscribers without this feature can also initiate regular IMS sessions, which are preceded by a specific signature that allows third parties to authorize these subscribers for priority service in that IMS session. This existing feature ensures that subscribers authorized for priority IMS sessions have signaling and user plane bearers provided with appropriate Quality of Service (QoS) and Allocation and Retention Policy (ARP), thus avoiding preemption in the event of congestion. The 3GPP Technical Specifications (TS) 23.501 (see up to V18.4.0), 23.502 (see up to V18.4.0), 23.503 (see up to V18.4.0), 23.401 (see up to V18.4.0), and 23.203 (see up to V17.2.0) have specified how fourth-generation (4G) and fifth-generation (5G) systems support MPS. Summary of the Invention

[0005] Systems and methods for supporting Multimedia Priority Service (MPS) for messaging over Internet Protocol (IP) Multimedia Subsystem (IMS) are disclosed. In one embodiment, a method for on-demand MPS for messaging, performed by a Proxy Call Session Control Function (P-CSCF), includes receiving from a Serving Call Session Control Function (S-CSCF) a notification indicating activation of MPS messaging for a User Equipment (UE) or subscriber. The method further includes receiving a Session Initiation Protocol (SIP) message from the UE and inserting a resource priority header into the SIP message, the resource priority header causing the SIP message to be processed according to the activation of MPS messaging for the UE or subscriber. In this way, support for MPS messaging over IMS is provided.

[0006] In one embodiment, the method further includes sending a SIP message including the resource priority header to the next hop in the delivery path of the SIP message.

[0007] In one embodiment, the resource priority header ensures that the SIP message is transmitted with a higher priority than other non-MPS services.

[0008] In one embodiment, the method further includes: subscribing to receive a notification from the S-CSCF indicating activation of MPS message transmission for the UE or subscriber. In one embodiment, subscribing to receive the notification includes: subscribing to registration change notifications for the UE or subscriber during the UE's IMS registration process.

[0009] The corresponding embodiments of P-CSCF and IMS nodes for implementing P-CSCF are also disclosed.

[0010] An embodiment of a method performed by the Home Subscriber Server (HSS) of IMS is also disclosed. In one embodiment, the method for on-demand MPS for message delivery performed by the HSS of IMS includes: updating the UE profile of a UE to activate MPS message delivery for the UE or subscriber; and sending a notification to the P-CSCF indicating the activation of MPS message delivery for the UE or subscriber.

[0011] In one embodiment, updating the UE profile is in response to a request received at the HSS or at the associated Unified Data Management (UDM) to activate the MPS message transmission for the UE or subscriber.

[0012] The corresponding embodiments of HSS and IMS nodes for implementing HSS are also disclosed.

[0013] Embodiments of a method executed in the core network of a cellular communication system are also disclosed. In one embodiment, a method executed in the core network of a cellular communication system includes: receiving, at the Network Open Function (NEF), a request from the Application Function (AF) to activate MPS message transmission for a UE or subscriber, and sending the request to the Unified Data Management (UDM) of the core network to activate MPS message transmission for the UE or subscriber. The method further includes, at the UDM, receiving, from the NEF, the request to activate MPS message transmission for the UE or subscriber, and updating the UE profile of the UE or subscriber to activate MPS message transmission for the UE or subscriber.

[0014] In one embodiment, the method further includes sending a notification at the UDM or at the associated Unified Data Repository (UDR) to the Policy and Control Function (PCF) indicating activation of MPS messaging for the UE or subscriber. In one embodiment, the method further includes starting a timer at the UDM or at the associated UDR associated with the activation of MPS messaging for the UE or subscriber, wherein MPS messaging for the UE or subscriber is deactivated upon timeout. In one embodiment, the method further includes receiving a notification at the PCF indicating activation of MPS messaging for the UE or subscriber, and sending a request to the Session Management Function (SMF) to update Policy and Charging Control (PCC) rules, wherein the update ensures that the default signaling bearer of the UE or subscriber is updated to prioritize MPS messaging services over other services in terms of Quality of Service (QoS). In one embodiment, the PCF subscribes to the UDR to be notified when MPS messaging changes.

[0015] In one embodiment, the method further includes sending an update message at the NEF to the UDR, the update message indicating activation of MPS message transmission for the UE or subscriber.

[0016] In one embodiment, the method further includes sending a request at the UDM to the Access and Mobility Management Function (AMF) to activate MPS message delivery for the UE or subscriber. In another embodiment, the method further includes, at the AMF, receiving the request to activate MPS message delivery for the UE or subscriber, and sending an update request to the SMF indicating activation of MPS message delivery for the corresponding PDU session of the UE. The method further includes, at the SMF, receiving the update request indicating activation of MPS message delivery for the corresponding PDU session of the UE, and sending a request to the PCF to notify the PCF of the activation of MPS message delivery for the corresponding PDU session of the UE. The method further includes, at the PCF, receiving the request from the SMF and initiating a process to update the PCC rules for the UE, wherein the update ensures that the default signaling bearer of the UE or subscriber is updated to a QoS that prioritizes MPS message delivery over other services.

[0017] Embodiments of a method performed by a NEF are also disclosed. In one embodiment, a method performed by a NEF in the core network of a cellular communication system includes: receiving a request from an AF to activate MPS message transmission for the UE or subscriber, and sending the request to a UDM of the core network to activate MPS message transmission for the UE or subscriber.

[0018] In one embodiment, the method further includes sending an update message to the UDR, the update message indicating activation of MPS message transmission for the UE or subscriber.

[0019] The document also discloses corresponding embodiments of NEF and network nodes used to implement NEF. Attached Figure Description

[0020] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate several aspects of this disclosure and, together with the specification, serve to explain the principles of this disclosure.

[0021] Figure 1 An example of a wireless communication system is shown, in which a user equipment (UE) has the ability to utilize a cellular access network, which is shown as the 3rd Generation Partnership Project (3GPP) (Radio) Access Network ((R)AN).

[0022] Figure 2 It shows Figure 1 A specific example of a wireless communication system in which the 3GPP core network is the fifth generation core (5GC).

[0023] Figure 3 This is a call flow illustrating an embodiment of the present disclosure according to the first option described herein.

[0024] Figure 4 This is a call flow illustrating an embodiment of the present disclosure according to the second option described herein.

[0025] Figure 5 This is a call flow illustrating an embodiment of the present disclosure according to the third option described herein.

[0026] Figure 6 and 7 This is a schematic block diagram of an exemplary embodiment of an Internet Protocol (IP) Multimedia Subsystem (IMS) node.

[0027] Figure 8 and 9 This is a schematic block diagram illustrating an exemplary embodiment of a network node. Detailed Implementation

[0028] Some embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. However, other embodiments are also included within the scope of the subject matter disclosed herein, and the disclosed subject matter should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.

[0029] Radio node: As used herein, a “radio node” is a radio access node or user equipment (UE).

[0030] Radio Access Node: As used herein, a “radio access node,” “radio network node,” or “radio access network node” is any node operating in the radio access network (RAN) of a cellular communication network for wirelessly transmitting and / or receiving signals. Some examples of radio access nodes include, but are not limited to, base stations (e.g., new radio (NR) base stations (gNBs) in 3GPP 5G NR networks or enhanced or evolved Node Bs (eNBs) in 3GPP LTE networks), high-power or macro base stations, low-power base stations (e.g., micro base stations, pico base stations, home eNBs, etc.), relay nodes, network nodes that implement some of the functions of a base station (e.g., network nodes that implement a gNB central unit (gNB-CU) or a gNB distributed unit (gNB-DU),) or network nodes that implement some of the functions of other types of radio access nodes.

[0031] Core Network Node: As used herein, a “core network node” is any type of node in the core network or any node that implements core network functions. Some examples of core network nodes include, for example, Mobility Management Entities (MMEs), Packet Data Network Gateways (P-GWs), Service Capability Opening Functions (SCEFs), Home Subscriber Servers (HSSs), etc. Other examples of core network nodes include nodes that implement Access and Mobility Management Functions (AMFs), User Plane Functions (UPFs), Session Management Functions (SMFs), Authentication Server Functions (AUSFs), Network Slice Selection Functions (NSSFs), Network Opening Functions (NEFs), Network Functions Library Functions (NRFs), Policy Control Functions (PCFs), Unified Data Management (UDMs), etc.

[0032] User Equipment (UE): As used herein, a UE is a wireless communication device that can be any type of wireless device accessing a wireless communication network (e.g., a cellular communication network) (i.e., served by a wireless communication network). Some examples of UEs include, but are not limited to: 3GPP UEs (i.e., UEs in 3GPP networks), machine-type communication (MTC) devices, and Internet of Things (IoT) devices. Such UEs can be, or can be integrated into, mobile phones, smartphones, sensor devices, meters, vehicles, home appliances, medical appliances, media players, cameras, or any type of consumer electronics, such as, but not limited to, televisions, radios, lighting fixtures, tablet computers, laptop computers, or PCs. A UE can be a portable, handheld, computer-integrated, or vehicle-mounted mobile device capable of transmitting voice and / or data via a wireless connection.

[0033] Network Node: As used herein, a “network node” can be any node that is part of the RAN or the core network of a cellular communication network / system. Other types of network nodes can be network nodes outside the RAN and core network of a cellular communication network, such as a network node hosting an Untrusted Application Function (AF) that accesses the 5GC via a Network Open Function (NEF).

[0034] IMS Node: As used herein, an “IMS node” is a node that implements all or part of the functions of an Internet Protocol (IP) Multimedia Subsystem (IMS) entity, such as a proxy call session control function (P-CSCF), an inquiry call session control function (I-CSCF), a service call session control function (S-CSCF), an access transfer control function (ATCF), an access gateway (AGW), etc.

[0035] Note that the descriptions given here focus on 3GPP cellular communication systems, and therefore, 3GPP terminology or similar terms are frequently used. However, the concepts disclosed herein are not limited to 3GPP systems.

[0036] Several challenges exist. Multimedia Priority Service (MPS) is an existing feature that enables subscribers with this feature to receive priority when initiating Internet Protocol (IP) Multimedia Subsystem (IMS) sessions. Subscribers without this feature can also initiate regular IMS sessions, which are preceded by a specific signature that allows third parties to authorize these subscribers for priority service in that IMS session. Existing features ensure that subscribers authorized for priority IMS sessions have signaling and user plane bearers provided with appropriate Quality of Service (QoS) and Allocation and Reservation Policy (ARP), thus protecting them from preemption in congestion situations. 3GPP TS23.501, 23.502, 23.503, 23.401, and 23.203 have specified how fourth-generation (4G) and fifth-generation (5G) systems support MPS.

[0037] Furthermore, there is a new requirement to prioritize on-demand messaging (MPS) for subscribers. This means that messages from subscribers authorized for MPS messaging will take precedence over other services. This feature can be independent of the original MPS feature. However, there is currently no solution specified for this requirement in the 3GPP specifications.

[0038] Some aspects of this disclosure and its embodiments may provide solutions to the above or other challenges. Three options are presented below (i.e., "Option 1", "Option 2" and "Option 3").

[0039] Regarding Option 1, the disclosed solution implementation relies on an external application function (AF) that sets up an MPS subscription in a unified data management (UDM) / unified data repository (UDR) when it wants to grant an MPS messaging subscription to a subscriber. This subscription is inherently temporary. In one embodiment, the subscription remains enabled in the UDM for a configured time period and is removed (i.e., disabled) once the timer expires.

[0040] In IMS, when an MPS messaging subscription is granted, the UDM notifies the Home Subscriber Server (HSS), which then updates the IMS subscription for that subscriber to activate MPS messaging. The HSS notifies the Service Call Session Control Function (S-CSCF) of this MPS messaging activation, and the S-CSCF notifies the Agent Call Session Control Function (P-CSCF) via a NOTIFY associated with the registration event packet. This allows the P-CSCF to insert a Resource Priority Header (RPH) when it receives a Session Initiation Protocol (SIP) message from a subscriber with active MPS messaging.

[0041] In a 5G system (5GS), the UDM / UDR notifies the Policy and Control Function (PCF) of changes to the MPS messaging subscription via NOTIFY. The PCF subscribes to the UDR to be notified of MPS messaging changes when an IMS Protocol Data Unit (PDU) session is established. The PCF then updates the Session Management Function (SMF) with new Policy and Charging Control (PCC) rules to update the User Plane Function (UPF) associated with the signaling bearer used for that PDU session with appropriate QoS and ARP corresponding to the MPS messaging.

[0042] When the timer in the UDM expires, repeat the same steps above to remove MPS message delivery to ensure normal SMS processing on the IMS is restored.

[0043] The timer applies to all options.

[0044] Typically, when an MPS message is delivered during a call flow, it triggers a new action. This complements the timers in the UDM.

[0045] Some embodiments may provide one or more of the following technical advantages. Embodiments of this disclosure provide solutions that reuse existing principles for MPS.

[0046] On this point, Figure 1An example of a wireless communication system 100 is shown, in which a UE 102 has the capability to utilize a cellular access network, shown as a 3GPP (Radio) Access Network ((R)AN) 104. The 3GPP (R)AN 104 can be a fourth-generation (4G) RAN (e.g., LTE or LTE Advanced RAN, including several base stations referred to as eNBs) or a 5G RAN (e.g., NR RAN (also known as NG-RAN), including several base stations referred to as gNBs). The 3GPP (R)AN 104 is connected to a core network, shown as a 3GPP core network 106 (e.g., an evolved packet core (EPC) or a 5G core (5GC)). As those skilled in the art will understand, the 3GPP core network 106 is connected to an Internet Protocol (IP) Multimedia Subsystem (IMS) 108.

[0047] Figure 2 It shows Figure 1 A specific example of a wireless communication system 100, wherein the 3GPP core network 106 is 5GC 200. As those skilled in the art will understand, 5GC 200 includes several network functions (NFs) connected by service-based interfaces in the control plane. NFs can be implemented as network elements on dedicated hardware, software instances running on dedicated hardware, or virtualized functions instantiated on a suitable platform (e.g., cloud infrastructure). As shown, 5GC 200 includes UPF 202, SMF 204, AMF 206, AUSF 208, NSSF 210, NEF 212, NRF 214, PCF 216, UDM 218, and Application Function (AF) 220. Note that although in Figure 2 In this context, AF 220 is shown as part of 5GC 200, but AF 220 may alternatively be external to 5GC 200 (e.g., an untrusted AF or a third-party AF).

[0048] Note that, although Figure 2 The 5GC 200 is presented as a service-based architecture, but reference point notation can be used alternatively. Reference point notation for 5G network architecture is used to develop detailed call flows in the specification standardization process. Each NF interacts directly with another NF. Intermediate functions can be used to route messages from one NF to another. In the control plane, a set of interactions between two NFs is defined as a service, making reuse possible. This service enables modularity. The user plane supports interactions such as forwarding operations between different UPF 202s.

[0049] Services provided by one NF to other authorized NFs can be exposed to the authorized NFs through service-based interfaces. Figure 2In this context, service-based interfaces are indicated by the letter "N" followed by the name of the NF (e.g., Namf for the service-based interface for AMF 206 and Nsmf for the service-based interface for SMF 204, etc.).

[0050] As those skilled in the art will understand, IMS 112 includes various IMS entities, such as the Proxy Call Session Control Function (P-CSCF) 222, the Interrogation Call Session Control Function (I-CSCF) 224, the Service Call Session Control Function (S-CSCF) 226, the Access Transfer Control Function (ATCF) 228, and the Access Gateway (AGW) 230. The operational details of P-CSCF 222, I-CSCF 224, S-CSCF 226, ATCF 228, and AGW 230 are well known to those skilled in the art and therefore will not be described herein.

[0051] A more detailed description of embodiments of the present disclosure will now be provided. These details include a description of three options, referred to herein as "Option 1", "Option 2", and "Option 3".

[0052] Option 1 is consistent with the above description.

[0053] Figure 3 This illustrates a call flow according to an embodiment of this disclosure based on option 1. Note that, for the sake of brevity, this process does not include the RAN resource update triggered by SMF 204 via AMF 206 to reflect the new ARP.

[0054] The steps in the call process are as follows: • Step 0: After UE 102 initiates an IMS PDU session based on the existing procedure in 3GPP TS 23.228, it performs IMS registration (i.e., UE 102 IMS registration). During this process, P-CSCF 222 subscribes to registration event packets from S-CSCF 226 to be notified of any changes in registration. In an alternative embodiment, in conjunction with IMS registration, P-CSCF 222 subscribes to MPS (MPS4MSG) policy changes for messaging from PCF 216 (via N5). That is, when PCF 216 receives notification from UDR (N36) regarding MP4MSG activation, PCF 216 notifies P-CSCF 222 of MPS via N5, whereby P-CSCF 222 stores a trigger to add an RPH header to an upcoming Mobile Origin (MO)SIP message. • Step 0.1: PCF 216 subscribes to the UDR for changes in the MPS message delivery subscription. This is an extension of the existing process to include MPS message delivery. • Step 1: The external / internal AF that needs to authorize MPS messaging features for a specific subscriber sends a request to NEF 212 via an Nnef_ParameterProvision_Update request (Activate MPS Messaging, ...) to activate MPS messaging for that subscriber. This is an extension of the existing request to support MPS messaging. • Step 2: NEF 212 sends a request to the UDM via a Nudm_SDM_ModifySubscription request (MPS Messaging, ...) to activate the MPS messaging subscription. This existing request is extended to support this new feature. In one embodiment, the UDM associates a configured timer with the MPS messaging activation. In one embodiment, the timer value may be suggested by the AF. When the timer expires, the UDM automatically removes the MPS messaging subscription for that subscriber. In one embodiment, the UDM starts the timer when it successfully responds to NEF 212. • Step 3: UDM notifies HSS of the update to the MPS subscription used for subscriber IMS subscription. • Step 4: The HSS notifies S-CSCF 226 that the subscriber now has MPS messaging (i.e., MPS messaging is enabled for the subscriber). • Step 4.5: S-CSCF 226 notifies P-CSCF 222: The subscriber now has MPS messaging (i.e., MPS messaging is enabled for the subscriber). Note that in the examples above in steps 4 and 4.5, P-CSCF 222 is notified of the activation of the MPS message for the subscriber (or associated UE 102) by receiving a notification from S-CSCF 226 notified by HSS. However, any mechanism can be used to notify P-CSCF 222 of the activation of MPS message delivery for the subscriber (or associated UE 102). Examples include the following: • Example 1: P-CSCF 222 receives notifications from the registration event packet. • Example 2: P-CSCF 222 subscribes to PCF 216 (or PCRF) for new events for MPS message transmission, and when PCF / PCRF is notified of the activation of MPS message transmission for the subscriber (or associated UE 102), PCF / PCRF then notifies P-CSCF 222. • Example 3: P-CSCF 222 sends a request to S-CSCF 226. S-CSCF 226 updates the HSS with the activation of MPS message delivery for the subscriber (or associated UE 102), and then S-CSCF 226 can notify P-CSCF 222 based on the update. • Step 5: UDM / UDR issues a Nudr_Notify request (MPS message delivery set) to notify PCF 216 that the subscriber has an MPS message delivery set. • Step 6: PCF 216 sends an Npcf_SMPolicyControl_Update service request (including new PCC rules for upgrading the signaling bearer) to SMF 204 to download the new PCC rules, thereby ensuring that the default signaling bearer is upgraded to the appropriate QoS and that the assigned ARP has an appropriate value. QoS and ARP are values ​​set to be suitable for MPS message delivery. • Step 7: SMF 204 sends an N4 session establishment / modification request to UPF 202 to download the new policy and PCC rules. • Step 8: SMF 204 returns the Npcf_SMPolicyControl_Update service response to PCF 216. • Step 9: The subscriber sends a SIP message to P-CSCF 222. • Step 10: P-CSCF 222 checks the UE context and, based on MPS message delivery being set and active, inserts an appropriate resource priority header to ensure the SIP message is properly processed before being proxied to the next hop. Alternatively, S-CSCF 226 receives the SIP message from P-CSCF 222 and, based on MPS message delivery being set and active, inserts an appropriate resource priority header to ensure the SIP message is properly processed before being proxied to the next hop.

[0055] Subsequently, the SIP message is passed to SMS_C. All nodes along the path ensure that the transmission of this message receives higher priority than other services.

[0056] In the embodiment where the timer started in the UDM in step 2 expires, the same steps are taken to ensure that the default signaling bearer is restored to its original state, and P-CSCF 222 is notified that the MPS message delivery has been removed. Since these steps are essentially the same—removing the MPS message delivery and updating the UPF with the corresponding new PCC rule—the call flow is not shown.

[0057] Figure 4This is a call flow diagram illustrating an embodiment of this disclosure according to option 2. Compared to option 1, in option 2, PCF 216 subscribes to the UDR to be notified when there are changes in MPS message transmission (step 0.1). Additionally, when AF activates MPS message transmission for the subscriber in step 1, NEF 212 updates the UDR (step 1b). This, in turn, triggers a notification to PCF 216 in step 5.

[0058] exist Figure 4 In the call flow, steps 0.1 and 5 are different, and step 1b is different from option 1 ( Figure 3 The comparison shown is additional.

[0059] Given that the additional and different steps have been explained above, all other steps are the same as in option 1 and will not be repeated.

[0060] In Option 3, as in Options 1 and 2, AMF206 is notified when AF activates MPS priority via NEF 212. UDM is updated as in Options 1 and 2.

[0061] Compared to Options 1 and 2, the following is new in Option 3: AMF 206 is notified of changes to MPS messaging in its subscription. AMF 206 then sends a PDU session update to SMF 204 to notify SMF 204 of the activation of MPS messaging for that PDU session. SMF 204 then sends a Policy Authorization Update Request to PCF 216 to obtain the new PCC rules. Subsequently, and as in Options 1 and 2, PCF 216 updates SMF 204 with the new PCC rules downloaded to UPF 202.

[0062] Figure 5 This illustrates a call flow according to an embodiment of this disclosure based on option 3, which shows the above process. Figure 5 The steps in the call process are as follows: • Steps 0, 1, 3, 4, and 4.5 are the same as the corresponding steps 0, 1, 3, 4, and 4.5 for options 1 and 2. • In step 4b, the changes in the MPS message delivery subscription are notified to AMF 206. • In step 5b, AMF 206 initiates an Nsmf_PDUSession_updateSMContext request to notify SMF204 to activate MPS message transmission for the PDU session. • In step 5c, SMF 204 initiates an Npcf_PolicyAuthorization_Update request to notify PCF216, which in turn provides SMF 204 with new PCC rules to upgrade QoS and ARP to appropriate values. • Steps 6-11 are the same as the corresponding steps for options 1 and 2.

[0063] Some exemplary technical specifications (TS) of the exemplary embodiments of this disclosure have the following effects: • P-CSCF: 3GPP TS 23.228. ° P-CSCF subscribes to S-CSCF to be notified of MPS message activation / deactivation to insert appropriate Resource Priority Header (RPH) based on received SIP messages when conditions apply. ° All Options • HSS: 3GPP TS 23.228. The HSS notifies the S-CSCF of MPS message activation / deactivation. Upon receiving the notification from the HSS, the S-CSCF notifies the P-CSCF of MPS message transmission activation / deactivation. ° All Options • UDM / UDR: 3GPP TS 23.502 / 23.501. UDM enables MPS message delivery (all options). ° (Optional) Start and stop timers associated with MPS for message delivery (all options) In option 1, notify the PCF due to subscription changes in MPS messaging. In option 3, the AMF is notified of subscription changes due to MPS messaging. • PCF: 3GPP TS 23.502 / 23.501. ° Process notifications related to MPS message delivery from UDM - Option 1. ° When conditions apply, notify the SMF of the new PCC rules associated with MPS message delivery—all options ° Subscriptions are notified of changes related to MPS message delivery in the subscription data – Option 1. • NEF: 3GPP TS 23.502 / 23.501. ° All options support requesting MPS message delivery to the UDM. ° Update UDR in Option 2 • AMF: 3GPP TS 23.502 / 23.501 – Option 3 ° AMF initiates SMF modifications when notified to activate MPS message transmission.

[0064] In options 1, 2, and 3 above, P-CSCF 222 is notified of the activation of MPS message transmission for the subscriber (or associated UE 102), and based on this notification, P-CSCF 222 inserts a priority header into the SIP message received from UE 102 for initiating the SMS. However, in another variation applicable to options 1, 2, and 3, P-CSCF 222 may not be notified of the activation of MPS message transmission for the subscriber (or associated UE 102). Instead, S-CSCF 226 is notified of the activation of MPS message transmission for the subscriber (or associated UE 102), and S-CSCF 226 inserts a priority header into the SIP message from UE 102, which S-CSCF 226 receives from P-CSCF 222.

[0065] Figure 6 This is a schematic block diagram of an IMS node 600 according to some embodiments of the present disclosure. Optional features are indicated by dashed boxes. The IMS node 600 may be a node that implements all or part of the functionality of an IMS entity as described herein (e.g., P-CSCF 222, HSS, etc.). As shown, the IMS node 600 includes one or more processors 604 (e.g., a central processing unit (CPU), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), and / or similar devices), memory 404, and network interface 608. The one or more processors 604 are also referred to herein as processing circuitry. The one or more processors 604 operate to provide one or more functions of the IMS node 600 as described herein. In some embodiments, the functionality is implemented in software, which is stored in, for example, memory 606 and executed by the one or more processors 604.

[0066] Figure 7 This is a schematic block diagram illustrating a virtualized embodiment of an IMS node 600 according to some embodiments of the present disclosure. As used herein, a “virtualized” IMS node is an implementation of the IMS node 600 in which at least a portion of the functionality of the IMS node 600 (e.g., via a virtual machine executed on a physical processing node in the network) is implemented as a virtual component. As shown, the IMS node 600 includes one or more processing nodes 700 coupled to or included as part of a network 702. Each processing node 700 includes one or more processors 704 (e.g., CPU, ASIC, FPGA, and / or similar), memory 706, and a network interface 708.

[0067] In this example, the functionality 710 of the IMS node 600 described herein is implemented at one or more processing nodes 700, or distributed in any desired manner across two or more processing nodes 700. In some specific embodiments, some or all of the functionality 710 of the IMS node 600 described herein is implemented as virtual components executed by one or more virtual machines, which are implemented in one or more virtual environments hosted by one or more processing nodes 700.

[0068] In some embodiments, a computer program is provided that includes instructions, which, when executed by at least one processor, cause the at least one processor to perform the functions of an IMS node 600 or a node (e.g., a processing node 700) that performs one or more of the functions 710 of the IMS node 600 implemented in a virtual environment, according to any embodiment described herein. In some embodiments, a carrier comprising the above-described computer program product is provided. The carrier is one of an electronic signal, an optical signal, a radio signal, or a computer-readable storage medium (e.g., a non-transitory computer-readable medium (e.g., memory)).

[0069] Figure 8 This is a schematic block diagram of a network node 800 according to some embodiments of the present disclosure. Optional features are indicated by dashed boxes. The network node 800 may be, for example, a network node that implements all or part of the functions of the NFs in the core network as described herein (e.g., one or more functions of AMF 206, UPF 202, SMF 204, PCF 216, UDM, UDR, etc. as described herein). As shown, the network node 800 includes one or more processors 804 (e.g., a central processing unit (CPU), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), and / or the like), memory 806, and network interface 808. The one or more processors 804 are also referred to herein as processing circuitry. The one or more processors 804 operate to provide one or more functions of the network node 800 as described herein (e.g., one or more functions of AMF 206, UPF 202, SMF 204, PCF 216, UDM, UDR, etc. as described herein). In some embodiments, the functionality is implemented in software, which is stored in, for example, memory 806 and executed by one or more processors 804.

[0070] Figure 9This is a schematic block diagram illustrating a virtualized embodiment of a network node 800 according to some embodiments of the present disclosure. Optional features are also indicated by dashed boxes. As used herein, a “virtualized” network node is an implementation of network node 800 in which at least a portion of the functionality of network node 800 (e.g., via a virtual machine executing on a physical processing node in the network) is implemented as a virtual component. As shown, network node 800 includes one or more processing nodes 900 coupled to or included as part of network 902. Each processing node 900 includes one or more processors 904 (e.g., CPU, ASIC, FPGA, etc.), memory 906, and network interface 908.

[0071] In this example, the functions 910 of the network node 800 described herein (e.g., one or more functions such as AMF 206, UPF 202, SMF 204, PCF 216, UDM, UDR, etc., as described herein) are implemented at one or more processing nodes 900 or distributed across two or more processing nodes 900 in any desired manner. In some specific embodiments, some or all of the functions 910 of the network node 800 described herein are implemented as virtual components executed by one or more virtual machines, which are implemented in one or more virtual environments hosted by one or more processing nodes 900.

[0072] In some embodiments, a computer program is provided that includes instructions, when executed by at least one processor, causing the at least one processor to perform the functions of network node 800 or the functions of one or more of the nodes (e.g., processing node 900) that implement the functions of network node 800 in a virtual environment, according to any embodiment described herein. In some embodiments, a carrier comprising the above-described computer program product is provided. The carrier is one of electronic signals, optical signals, radio signals, or computer-readable storage media (e.g., non-transitory computer-readable media (e.g., memory)).

[0073] Any suitable steps, methods, features, functions, or benefits disclosed herein may be performed by one or more functional units or modules of one or more virtual devices. Each virtual device may include several such functional units. These functional units may be implemented by processing circuitry, which may include one or more microprocessors or microcontrollers, and other digital hardware, including digital signal processors (DSPs), application-specific digital logic, etc. The processing circuitry may be configured to execute program code stored in memory, which may include one or more types of memory, such as read-only memory (ROM), random access memory (RAM), cache memory, flash memory devices, optical storage devices, etc. The program code stored in memory includes program instructions for executing one or more telecommunications and / or data communication protocols and instructions for executing one or more techniques described herein. In some embodiments, the processing circuitry may be used to cause corresponding functional units to perform corresponding functions according to one or more embodiments of this disclosure.

[0074] While the processes in the figures may illustrate a particular sequence of operations performed by certain embodiments of this disclosure, it should be understood that such a sequence is exemplary (e.g., alternative embodiments may perform operations in a different order, combine some operations, overlap some operations, etc.).

[0075] Some exemplary embodiments of this disclosure are as follows:

[0076] Example 1: A method for On-Demand Multimedia Priority Service (MPS) performed by the Proxy Call Session Control Function (P-CSCF) (222), the method comprising any one or more of the following: subscription ( Figure 3 Step 0; Figure 4 Step 0; Figure 5 Step 0) User equipment (UE) (102) (or subscriber) registration change notification; receive ( Figure 3 Step 4.5; Figure 4 Step 4.5; Figure 5 Step 4.5) instructs the notification to activate MPS message transmission for the UE (102) (or subscriber); receives from the UE (102) ( Figure 3 Step 9; Figure 4 Step 9; Figure 5 Step 10) Session Initiation Protocol (SIP) message; and inserting the Resource Priority header (...) Figure 3 Step 10; Figure 4 Step 10; Figure 5 In step 11), the resource priority header in the SIP message causes the SIP message to be processed according to the activation MPS message transmission for the UE (102).

[0077] Example 2: The method described in Example 1 further includes: sending a SIP message including the resource priority header to the next hop in the delivery path of the SIP message.

[0078] Example 3: The method described in Example 2, wherein the SIP message is transmitted via a cellular communication system, and the resource priority header ensures that the SIP message is transmitted through the cellular communication system according to the specific Quality of Service (QoS) and / or Allocation and Retention Policy (ARP) for MPS services.

[0079] Example 4: The method described in Example 1 or 2, wherein the resource priority header ensures that the SIP message is transmitted with a higher priority than other non-MPS services.

[0080] Example 5: The method according to any one of Examples 1 to 4, wherein the subscription notification includes subscribing to the registration change notification of the UE (102) (or subscriber) from the Home Subscriber Server (HSS), and the receiving notification includes receiving from the HSS a notification indicating that MPS message transmission is activated for the UE (102) (or subscriber).

[0081] Example 6: The method as described in any one of Examples 1 to 5, wherein the subscription to the registration change notification of the UE (102) (or subscriber) is performed during the IMS registration process of the UE (102) after an IMS PDU session has been established for the UE (102).

[0082] Example 7: A proxy call session control function P-CSCF (222) adapted to perform the method as described in any one of Examples 1 to 6.

[0083] Example 8: An Internet Protocol IP Multimedia Subsystem (IMS) node for implementing the proxy call session control function P-CSCF (222), the IMS node comprising: a communication interface; and processing circuitry associated with the communication interface, the processing circuitry being configured to cause the IMS node to perform the method as described in any one of Examples 1 to 6.

[0084] Example 9: A method for On-Demand Multimedia Priority Service (MPS) performed by a Service Call Session Control Function (S-CSCF) (226), the method comprising any one or more of the following: receiving ( Figure 3 Step 4; Figure 4 Step 4; Figure 5Step 4) Indicates a notification to activate MPS message transmission for UE (102) (or subscriber); receives a Session Initiation Protocol (SIP) message from the UE (102) from the Proxy Call Session Control Function (P-CSCF) (222); and inserts a resource priority header into the SIP message, the resource priority header causing the SIP message to be processed in accordance with the activation of MPS message transmission for the UE (102).

[0085] Example 10: The method as described in Example 9 further includes: sending the SIP message including the resource priority header to the next hop in the delivery path of the SIP message.

[0086] Example 11: The method as described in Example 10, wherein the SIP message is transmitted via a cellular communication system, and the resource priority header ensures that the SIP message is transmitted through the cellular communication system according to the specific Quality of Service (QoS) and / or Allocation and Retention Policy (ARP) for MPS services.

[0087] Example 12: The method described in Example 9 or 10, wherein the resource priority header ensures that SIP messages are transmitted with a higher priority than other non-MPS services.

[0088] Example 13: A Service Call Session Control Function (S-CSCF) (226) adapted to perform the method as described in any one of Examples 9 to 12.

[0089] Example 14: An Internet Protocol IP Multimedia Subsystem (IMS) node for implementing Service Call Session Control Function (S-CSCF) (226), the IMS node comprising: a communication interface; and processing circuitry associated with the communication interface, the processing circuitry being configured to cause the IMS node to perform the method as described in any one of Examples 9 to 12.

[0090] Example 15: A method for On-Demand Multimedia Priority Service (MPS) executed by the Service Call Session Control Function (S-CSCF) (226) of the Internet Protocol IP Multimedia Subsystem (IMS), the method comprising any one or more of the following: receiving from the Proxy Call Session Control Function (P-CSCF) (222) of the IMS ( Figure 3 Step 0; Figure 4 Step 0; Figure 5 Step 0) Subscribe to the registration change notification for the user equipment (UE) (102) (or subscriber); receive ( Figure 3 Step 4; Figure 4 Step 4; Figure 5Step 4) Notification to activate MPS message transmission for the UE (102) (or subscriber) (e.g., from HSS); and sending ( Figure 3 Step 4.5; Figure 4 Step 4.5; Figure 5 Step 4.5) instructs the notification to activate MPS message transmission for the UE (102) (or subscriber).

[0091] Example 16: The method as described in Example 15, wherein receiving a notification to activate MPS message transmission for the UE (102) (or subscriber) is in response to a request received at the HSS or at the associated UDM for activating MPS message transmission for the UE (102) (or subscriber).

[0092] Example 17: The method as described in Example 15 or 16, wherein receiving the subscription request includes receiving the subscription request from the P-CSCF (222) during the IMS registration process of the UE (102) after an IMS PDU session has been established for the UE (102).

[0093] Example 18: A Service Call Session Control Function (S-CSCF) (226) of Internet Protocol IP Multimedia Subsystem (IMS), wherein the HSS is adapted to perform the method as described in any one of Examples 15 to 17.

[0094] Example 19: An Internet Protocol IP Multimedia Subsystem (IMS) node for implementing Service Call Session Control Function (S-CSCF) (226), the IMS node comprising: a communication interface; and processing circuitry associated with the communication interface, the processing circuitry being configured to cause the IMS node to perform the method as described in any one of Examples 15 to 17.

[0095] Example 20: A method for providing On-Demand Multimedia Priority Service (MPS) executed by the Home Subscriber Server (HSS) of the Internet Protocol IP Multimedia Subsystem (IMS), the method comprising any one or more of the following: updating ( Figure 3 Step 3; Figure 4 Step 3; Figure 5 Step 3) The UE profile of the UE (102) is used to activate the transmission of MPS messages for the UE (102) (or subscriber); and a message is sent to the P-CSCF (222) ( Figure 3 Step 4.5; Figure 4 Step 4.5; Figure 5 Step 4.5) instructs the notification to activate MPS message transmission for the UE (102) (or subscriber).

[0096] Example 21: The method as described in Example 20, wherein updating the UE profile is in response to a request received at the HSS or at the associated UDM to activate MPS message transmission for the UE (102) (or subscriber).

[0097] Example 22: A Home Subscriber Server (HSS) of Internet Protocol IP Multimedia Subsystem (IMS), the HSS being adapted to perform the method as described in any one of Examples 20 to 21.

[0098] Example 23: An Internet Protocol IP Multimedia Subsystem (IMS) node for implementing a Home Subscriber Server (HSS), the IMS node comprising: a communication interface; and processing circuitry associated with the communication interface, the processing circuitry being configured to cause the IMS node to perform the method as described in any one of Examples 20 to 21.

[0099] Example 24: A method performed in the core network (106, 200) of a cellular communication system (100), the method comprising: • At Network Open Function (NEF) (212): ° Received from application function AF ( Figure 3 Step 1; Figure 4 Step 1) is a request to activate the Multimedia Priority Service (MPS) message transmission for the user equipment (UE) (102) (or subscriber); ° Send to the Unified Data Management (UDM) of the core network (106, 200) ( Figure 3 Step 2; Figure 4 Step 2) is used to request the activation of MPS message transmission for the UE (102) (or subscriber); • At the UDM: ° Receive from the NEF (212) Figure 3 Step 2; Figure 4 Step 2) is used to request the activation of MPS message transmission for the UE (102) (or subscriber); ° Update ( Figure 3 Step 3; Figure 4 Step 2) The UE profile of the UE (102) (or subscriber) is used to activate MPS message transmission for the UE (102) (or subscriber).

[0100] Example 25: The method as described in Example 24 further includes: sending ( ) to the Policy and Control Function PCF (216) at the UDM or at the associated UDR. Figure 3 Step 5; Figure 4 Step 5) Instructs the notification to activate MPS message transmission for the UE (102) (or subscriber).

[0101] Example 26: The method as described in Example 25 further includes: starting a timer associated with the activation of MPS message transmission for the UE (102) (or subscriber) at the UDM or at the associated UDR, wherein the MPS message transmission for the UE (102) (or subscriber) is deactivated when the timer expires.

[0102] Example 27: The method as described in Example 25 or 26 further includes: • At the PCF (216): ° Receive ( Figure 3 Step 5; Figure 4 Step 5) instructs the notification to activate MPS message transmission for the UE (102) (or subscriber); and ° Send (to Session Management Function SMF (204)) Figure 3 Step 6; Figure 4 Step 6) is a request to update policy and charging control (PCC) rules (e.g., to ensure that the default signaling bearer of the UE (102) (or subscriber) is updated to prioritize MPS messaging service over other services in terms of Quality of Service (QoS).

[0103] Example 28: The method as described in Example 27, wherein the PCF (216) is notified to the UDR when the MPS message transmission changes.

[0104] Example 29: The method as described in any one of Examples 24 to 28 further includes: at the NEF (212), sending ( Figure 4 Step 1b) Update message, the update message indicating that MPS message transmission is activated for the UE (102) (or subscriber).

[0105] Example 30: The method as described in Example 24 further includes: at the UDM, sending ( ) to the Access and Mobility Management Function (AMF) (206) Figure 5 Step 4b) is used to request the activation of MPS message transmission for the UE (102) (or subscriber).

[0106] Example 31: The method as described in Example 30 further includes: • At the AMF (206): ° Receive ( Figure 5 The request to activate MPS message transmission for the UE (102) (or subscriber) as described in step 4b); ° Send (to Session Management Function SMF (204)) Figure 5Step 5b) instructs an update request to activate MPS message transmission for the corresponding PDU session of the UE (102); and • At the SMF (204): ° Receive ( Figure 5 Step 5b) indicates the update request for activating the MPS message transmission for the corresponding PDU session of the UE (102); and ° Send (to the policy and control function PCF (216)) Figure 5 Step 5c) Notify the PCF (216) of the request to transmit the corresponding PDU session activation MPS message for the UE (102); and • At the PCF (216): ° Receive ( Figure 5 Step 5c) The request from the SMF (204); and ° Initiate ( Figure 5 Step 6) is a process for updating the policy and charging control (PCC) rules of the UE (102) (e.g., to ensure that the default signaling bearer of the UE (102) (or subscriber) is updated to prioritize MPS messaging service over other services in terms of Quality of Service (QoS).

Claims

1. A method for On-Demand Multimedia Priority Service (MPS) performed by a proxy call session control function (P-CSCF) (222), the method comprising: Receive (Figure 3, step 4.5; Figure 4, step 4.5; Figure 5, step 4.5) notification from the Service Call Session Control Function S-CSCF (226) indicating the transmission of an MPS message for the User Equipment (UE) (102) or subscriber; Receive (Figure 3, step 9; Figure 4, step 9; Figure 5, step 10) Session Initiation Protocol (SIP) message from the UE (102); and A resource priority header is inserted (Figure 3, step 10; Figure 4, step 10; Figure 5, step 11) into the SIP message, the resource priority header causing the SIP message to be processed according to the MPS message transmission for the UE (102) or subscriber activation.

2. The method of claim 1, further comprising: Send the SIP message, including the resource priority header, to the next hop in the delivery path of the SIP message.

3. The method of claim 1 or 2, wherein, The resource priority header ensures that the SIP message is transmitted with a higher priority than other non-MPS services.

4. The method of any one of claims 1 to 3, further comprising: Subscribe to receive a notification from the S-CSCF (226) indicating that the MPS message transmission is activated for the UE (102) or subscriber.

5. The method of claim 4, wherein, Subscribing to receive the notifications includes: subscribing to registration change notifications for the UE (102) or its subscribers during the IMS registration process of the UE (102).

6. A proxy call session control function P-CSCF (222) adapted to perform the method as described in any one of claims 1 to 5.

7. An Internet Protocol IP Multimedia Subsystem (IMS) node for implementing the proxy call session control function P-CSCF (222), the IMS node comprising: Communication interface; as well as A processing circuit associated with the communication interface, the processing circuit being configured to cause the IMS node to perform the method as described in any one of claims 1 to 5.

8. A method for providing On-Demand Multimedia Priority Service (MPS) executed by a Home Subscriber Server (HSS) of an Internet Protocol (IP) Multimedia Subsystem (IMS), the method comprising: Update (Figure 3, step 3; Figure 4, step 3; Figure 5, step 3) the UE profile of the user equipment (UE) (102) to activate MPS message transmission for said UE (102) or subscriber; and Send a notification to the proxy call session control function P-CSCF (222) (Figure 3, step 4.5; Figure 4, step 4.5; Figure 5, step 4.5) indicating the activation of MPS message transmission for the UE (102) or subscriber.

9. The method of claim 8, wherein, Updating the UE profile is in response to a request received at the HSS or at the associated Unified Data Management UDM to activate MPS message transmission for the UE (102) or subscriber.

10. A Home Subscriber Server (HSS) for an Internet Protocol IP Multimedia Subsystem (IMS), the HSS being adapted to perform the method as described in any one of claims 8 to 9.

11. An Internet Protocol IP Multimedia Subsystem (IMS) node for implementing a Home Subscriber Server (HSS), the IMS node comprising: Communication interface; as well as A processing circuit associated with the communication interface, the processing circuit being configured to cause the IMS node to perform the method as described in any one of claims 8 to 9.

12. A method performed in the core network (106, 200) of a cellular communication system (100), the method comprising: • At Network Open Function (NEF) (212): ° Receive a request from the application function AF (Figure 3, step 1; Figure 4, step 1) for the transmission of a Multimedia Priority Service (MPS) message for the user equipment (UE) (102) or subscriber; ° Send (Figure 3, step 2; Figure 4, step 2) to the Unified Data Management UDM of the core network (106, 200) to request the transmission of MPS message for the UE (102) or subscriber; • At the UDM: ° Receive from the NEF (212) (Figure 3, step 2; Figure 4, step 2) a request to activate MPS message transmission for the UE (102) or subscriber; as well as ° Update (Figure 3, step 3; Figure 4, step 2) the UE profile of the UE (102) or subscriber to activate MPS message transmission for the UE (102) or subscriber.

13. The method of claim 12, further comprising: At the UDM or at the associated unified data repository UDR, a notification instructing the Policy and Control Function (PCF) (216) to activate MPS message delivery for the UE (102) or subscriber is sent (Figure 3, step 5; Figure 4, step 5).

14. The method of claim 13, further comprising: At the UDM or the associated UDR, a timer is started that is associated with the activation of MPS message transmission for the UE (102) or subscriber, wherein the MPS message transmission for the UE (102) or subscriber is deactivated when the timer expires.

15. The method of claim 13 or 14, further comprising: • At the PCF (216): ° Receive (Figure 3, step 5; Figure 4, step 5) a notification indicating the activation of the MPS message transmission for the UE (102) or subscriber; and ° Send a request to the Session Management Function (SMF) (Figure 3, step 6; Figure 4, step 6) to update the Policy and Charging Control (PCC) rules, wherein the update ensures that the default signaling bearer of the UE (102) or subscriber is updated to prioritize MPS messaging service over other services in terms of Quality of Service (QoS).

16. The method of claim 15, wherein, The PCF (216) subscribes to the UDR to be notified when MPS message transmission changes.

17. The method of any one of claims 12 to 16, further comprising: At the NEF (212), an update message (Figure 4, step 1b) is sent to the UDR, the update message indicating the activation of MPS message transmission for the UE (102) or subscriber.

18. The method of claim 12, further comprising: At the UDM, a request to activate MPS message transmission for the UE (102) or subscriber is sent to the Access and Mobility Management Function (AMF) (206) (Figure 5, step 4b).

19. The method of claim 18, further comprising: • At the AMF (206) ° Receive (Figure 5, step 4b) a request to activate MPS message transmission for the UE (102) or subscriber; ° Send an update request (Figure 5, step 5b) to the Session Management Function (SMF) (204) instructing the transmission of the corresponding PDU Session Activation MPS message for the UE (102); and • At the SMF (204): ° Receive (Figure 5, step 5b) the update request indicating the transmission of the corresponding PDU session activation MPS message for the UE (102); and ° Send a request to the Policy and Control Function (PCF) (216) (Figure 5, step 5c) to notify the PCF (216) of a request to transmit the corresponding PDU session activation MPS message for the UE (102); and • At the PCF (216): ° Receive the request from the SMF (204) (Figure 5, step 5c); and ° Initiate (Figure 5, step 6) a process to update the policy and charging control (PCC) rules of the UE (102), wherein the update ensures that the default signaling bearer of the UE (102) or subscriber is updated to prioritize MPS messaging service over other services in terms of Quality of Service (QoS).

20. A method performed in a Network Open Function (NEF) (212) in the core network (106, 200) of a cellular communication system (100), the method comprising: Received from application function AF (Figure 3, step 1); Figure 4, step 1) is a request to activate the Multimedia Priority Service (MPS) message for the User Equipment (UE) (102) or subscriber; and Send (Figure 3, step 2; Figure 4, step 2) to the Unified Data Management (UDM) of the core network (106, 200) to request the transmission of the MPS message for the UE (102) or subscriber.

21. The method of claim 20, further comprising: Send an update message (Figure 4, step 1b) to the Unified Data Repository (UDR), the update message indicating the activation of MPS message transmission for the UE (102) or subscriber.

22. A network open function (NEF) (212) for a core network (106, 200) of a cellular communication system (100), said NEF (212) being adapted to perform the method as claimed in any one of claims 20 to 21.

23. A network node for implementing the Network Open Function (NEF) (212) of the core network (106, 200) of a cellular communication system (100), the network node comprising: Communication interface; as well as A processing circuit associated with the communication interface, the processing circuit being configured to cause the network node to perform the method according to any one of claims 20 to 21.

Images