Upf reselection for downlink data size support in a communications network

Abstract

This disclosure provides a method for Small Data Transmission, SDT, in a communications network. The method comprises transmitting from a radio access network node (NG-RAN) to a access and mobility management node (AMF) an indication (step 2) that at least one of a PDU session and / or a QoS flow are subject to SDT, wherein the PDU session is identified by a PDU session ID, and / or wherein the QoS flow is identified by a QoS Flow Identifier, QFI; transmitting (step. 3) from the access and mobility management node to a session management node (SMF) a request including an indication of the PDU sessions and / or QoS flows subject to SDT, particularly wherein the indication is based on the received information for SDT from the radio access network node or local policy, and particularly wherein the request is a Nsmf_PDUSession_UpdateSMContext Request; inserting, selecting or reselecting (I-UPF reselection) at the session management node a user plane node that supports SDT, particularly if the current user plane node does not support SDT; and transmitting (steps 5 and 6) from the session management node to the radio access network node via the access and mobility management node, N3 tunnel information parameters associated with the selected user plane node.

Description

[0001] UPF RESELECTION FOR DOWNLINK DATA SIZE SUPPORT IN A COMMUNICATIONS NETWORK

[0002] TECHNICAL FIELD

[0003] The present invention generally relates to the selection and reselection of a User Plane Function (UPF) in a 3GPP mobile network, and more specifically, the invention relates to UPF reselection in a Small Data Transmission scenario.

[0004] BACKGROUND

[0005] Small Data Transmission (SDT) is a procedure defined by the Third Generation Partnership Project (3GPP) that allows data and signaling transmission from the User Equipment (UE) to the network while the UE remains in an RRCJNACTIVE state, meaning it does not switch to an RRC_CONNECTED state. SDT operates on a radio bearer basis and is initiated by the UE, i.e., mobile originated SDT (MO-SDT), only if the following conditions are met: the amount of uplink (UL) data waiting to be transmitted across all radio bearers for which SDT is enabled is below a configured threshold, the downlink (DL) Reference Signal Received Power (RSRP) is above a configured threshold and a valid SDT resource is available.

[0006] Mobile terminated Small Data Transmission (MT-SDT) is a procedure that enables the initial downlink (DL) data reception and subsequent uplink (UL) and DL data transmissions for User Equipment (UE) in an RRCJNACTIVE state. During an MT-SDT session, the UE remains in the RRCJNACTIVE state throughout the SDT transmission. This occurs when the UE receives an MT-SDT indication in the Radio Access Network (RAN) paging message, following a decision by the serving Next Generation Node B (gNB) to use MT-SDT paging.

[0007] The User Equipment (UE) supports an RRCJNACTIVE state with an Extended Discontinuous Reception (eDRX) period longer than 10.24 seconds. When the UE is unreachable due to this long eDRX in the RRCJNACTIVE state, the New Generation Radio Access Network (NG-RAN) sends a request to the Fifth Generation Core Network (5GCN) for handling mobile terminated (MT) data and signaling within the Core Network (CN). The 5GCN then begins buffering the data and sends an N2 confirmation to the NG-RAN, allowing the NG-RAN to release the UE to the RRCJNACTIVE state. When the UE resumes network activity and the serving Next Generation Node B (gNB) moves it to the RRC_CONNECTED state, the 5GCN, specifically the User Plane Function (UPF), which has been buffering the data, must be notified to deliver any pending downlink (DL) data to the UE. This process is specified in the UE Triggered Connection Resume procedure for the RRCJNACTIVE state.

[0008] In the User Equipment (UE) Triggered Connection Resume procedure for the RRCJNACTIVE state, the Connection Resume process allows the UE to transition from the RRCJNACTIVE state to the RRC_CONNECTED state. To support the Network Triggered Connection Resume for a UE in the RRCJNACTIVE state with Core Network (CN) based mobile terminated (MT) communication handling, the New Generation Radio Access Network (NG-RAN) performs Radio Access Network (RAN) paging towards the UE when there is downlink (DL) MT data coming from the CN. This paging is based on an N2 message from the Access and Mobility Management Function (AMF) to trigger the UE Triggered Connection Resume procedure.

[0009] In the Network Triggered Connection Resume procedure for the RRCJNACTIVE state with Core Network (CN) based mobile terminated (MT) communication handling, the UE is in a CM-CONNECTED state with RRCJNACTIVE. This setup involves high latency communication. The procedure can be triggered by MT data, an N1 procedure from the Session Management Function (SMF) and User Plane Function (UPF), or other Network Functions (NFs). During this process, the New Generation Radio Access Network (NG- RAN), specifically the Next Generation Node B (gNB), performs Radio Access Network (RAN) paging towards the UE based on an N2 message from the Access and Mobility Management Function (AMF). This paging is intended to trigger the UE Triggered Connection Resume procedure.

[0010] A problematic aspect of the current solutions is that providing the downlink (DL) data size may not be supported by the User Plane Function (UPF). In the Evolved Packet System (EPS), this functionality was based on Non-Access Stratum (NAS) negotiation between the User Equipment (UE) and the Core Network (CN). During the Packet Data Unit (PDU) session establishment for a UE that might use the RRCJNACTIVE state with Small Data Transmission (SDT), the CN does not know if this functionality is required. As a result, the UPF might be selected without this knowledge, potentially leading to an inadequate UPF being chosen. Consequently, related procedures, such as the paging procedure, may not work as expected or may fail. SUMMARY

[0011] The invention is set out in the appended set of claims.

[0012] An object of the invention is to enable UPF insertion, selection, or reselection for SDT scenarios.

[0013] An aspect of the invention relates to a method performed by a radio access network node for Small Data Transmission, SDT, in a communications network. The method comprises transmitting from a radio access network node to a access and mobility management node an indication that at least one of a PDU session and / or a QoS flow are subject to SDT, wherein the PDU session is identified by a PDU session ID, and / or wherein the QoS flow is identified by a QoS Flow Identifier, QFI; and receiving at the radio access network node from a session management node via the access and mobility management node, N3 tunnel information parameters associated with a selected user plane node by the session management node. In some embodiments, the indication from the radio access network node to the access and mobility management node is transmitted in a N2 MT Communication Handling request message. In some embodiments, the method further comprises sending from the access and mobility management node to the radio access network node, a N2 MT Communication Handling response message, particularly wherein the response message indicates that the access and mobility management node acknowledges the request or that the access and mobility management node has taken the request into account. In some embodiments, the access and mobility management node provides to the radio access network node the N3 tunnel information parameters received from the session management node in a N2 MT Communication Handling response message or triggers a separate PDU Session Resource Modify procedure to update the N3 tunnel information in the radio access network node. In some embodiments, the access and mobility management node provides to the radio access network node an indication of support for MT-SDT for the PDU session, particularly based on an indication from the session management node. In some embodiments, the access and mobility management node includes the DL data size information in the N2 DL Data Notification message to the radio access network node, if the DL data size information is provided by the session management node to the access and mobility management node. In some embodiments, the method further comprises performing at the radio access network node, RAN paging towards the UE based on the parameters provided by the access and mobility management node and setting at the radio access network node the MT-SDT flag in the paging message if the DL data size is provided, wherein the MS-SDT flag is set if the DL data size crossed a threshold or a DL data size flag is provided from the session management node. In some embodiments, If the LIL NG-ll UP TNL Information IE is included in the MT COMMUNICATION HANDLING RESPONSE message, the radio access network node shall update the new user plane node endpoint of the NG-U transport bearer information, for delivery of UL PDUs to the session management node for the indicated QoS flows. In some embodiments, the method further incudes: determining at an radio access network node, an eDRX cycle value for a User Equipment, UE, in RRCJNACTIVE state; initiating at the radio access network node, a Connection Inactive procedure with Core Network, CN, based Mobile Terminated, MT, communication handling; and transmitting from the radio access network node to the access and mobility management node, a N2 MT Communication Handling request message, wherein the request message indicates the UE's transition to RRCJNACTIVE state and provides the eDRX cycle value for the RRCJNACTIVE state. In some embodiments, the radio access network node is a New Radio - Radio Access Network, NG-RAN, the access and mobility management node is an Access and Mobility Management Function, AMF, the session management node is a Session Management Function, SMF, the user plane node is a User Plane Function, UPF, particularly wherein the SMF is an Intermediate SMF, l-SMF, or a Visited SMF, V-SMF, and particularly wherein the UPF is an Intermediate UPF, l-UPF, or a Visited UPF, V-UPF.

[0014] A further aspect of the invention relates to a method performed by a access and mobility management node for Small Data Transmission, SDT, in a communications network. The method comprises receiving at a access and mobility management node from a radio access network node an indication that at least one of a PDU session and / or a QoS flow are subject to SDT, wherein the PDU session is identified by a PDU session ID, and / or wherein the QoS flow is identified by a QoS Flow Identifier, QFI; transmitting from the access and mobility management node to a session management node a request including an indication of the PDU sessions and / or QoS flows subject to SDT, particularly wherein the indication is based on the received information for SDT from the radio access network node or local policy, and particularly wherein the request is a Nsmf PDUSession UpdateSMContext Request; and transmitting from the access and mobility management node to the radio access network node via the access and mobility management node, N3 tunnel information parameters associated with a selected user plane node received from the session management node. In some embodiments, the indication from the radio access network node to the access and mobility management node is transmitted in a N2 MT Communication Handling request message. In some embodiments, the method further comprises sending from the access and mobility management node to the radio access network node, a N2 MT Communication Handling response message, particularly wherein the response message indicates that the access and mobility management node acknowledges the request or that the access and mobility management node has taken the request into account. In some embodiments, the access and mobility management node provides to the radio access network node the N3 tunnel information parameters received from the session management node in a N2 MT Communication Handling response message or triggers a separate PDU Session Resource Modify procedure to update the N3 tunnel information in the radio access network node. In some embodiments, the access and mobility management node provides to the radio access network node an indication of support for MT-SDT for the PDU session, particularly based on an indication from the session management node. In some embodiments, the access and mobility management node includes the DL data size information in the N2 DL Data Notification message to the radio access network node, if the DL data size information is provided by the session management node to the access and mobility management node. In some embodiments, the method further comprises performing at the radio access network node, RAN paging towards the UE based on the parameters provided by the access and mobility management node and setting at the radio access network node the MT-SDT flag in the paging message if the DL data size is provided, wherein the MS-SDT flag is set if the DL data size crossed a threshold or a DL data size flag is provided from the session management node. In some embodiments, If the UL NG-U UP TNL Information IE is included in the MT COMMUNICATION HANDLING RESPONSE message, the radio access network node shall update the new user plane node endpoint of the NG-U transport bearer information, for delivery of UL PDUs to the session management node for the indicated QoS flows. In some embodiments, the method further incudes: determining at an radio access network node, an eDRX cycle value for a User Equipment, UE, in RRCJNACTIVE state; initiating at the radio access network node, a Connection Inactive procedure with Core Network, CN, based Mobile Terminated, MT, communication handling; and transmitting from the radio access network node to the access and mobility management node, a N2 MT Communication Handling request message, wherein the request message indicates the UE's transition to RRCJNACTIVE state and provides the eDRX cycle value for the RRCJNACTIVE state. In some embodiments, the radio access network node is a New Radio - Radio Access Network, NG-RAN, the access and mobility management node is an Access and Mobility Management Function, AMF, the session management node is a Session Management Function, SMF, the user plane node is a User Plane Function, UPF, particularly wherein the SMF is an Intermediate SMF, l-SMF, or a Visited SMF, V-SMF, and particularly wherein the UPF is an Intermediate UPF, l-UPF, or a Visited UPF, V-UPF.

[0015] A further aspect of the invention relates to a method performed by a session management node for Small Data Transmission, SDT, in a communications network. The method comprises receiving at a session management node from a access and mobility management node a request including an indication of the PDU sessions and / or QoS flows subject to SDT, particularly wherein the indication is based on the received information for SDT from the radio access network node or local policy, and particularly wherein the request is a Nsmf PDUSession UpdateSMContext Request; inserting, selecting or reselecting at the session management node a user plane node that supports SDT, particularly if the current user plane node does not support SDT; and transmitting from the session management node to a radio access network node via the access and mobility management node, N3 tunnel information parameters associated with the selected user plane node. In some embodiments, the method further comprises transmitting from the session management node to the user plane node rules for SDT data handling, particularly wherein the rules are for Mobile Terminated SDT, MT-SDT, and particularly wherein the rules are transmitted as part of the N4 Session establishment or update procedure. In some embodiments, the method further comprises transmitting from the session management node to the user plane node an N4 Session establishment message indicating the user plane node to report DL data size. In some embodiments, the method further comprises transmitting from the session management node to the user plane node an indication of support for MT-SDT for the PDU session. In some embodiments, the method further comprises providing from the user plane node to the session management node, DL data size information when sending Data Notification, and wherein the session management node includes the DL data size information in the Namf MT EnableUEReachability message to the access and mobility management node, particularly wherein the DL data size information is a DL data size parameter or a DL data size flag indicating that the DL data size crossed a threshold configured in the session management node. In some embodiments, the radio access network node is a New Radio - Radio Access Network, NG-RAN, the access and mobility management node is an Access and Mobility Management Function, AMF, the session management node is a Session Management Function, SMF, the user plane node is a User Plane Function, UPF, particularly wherein the SMF is an Intermediate SMF, l-SMF, or a Visited SMF, V-SMF, and particularly wherein the UPF is an Intermediate UPF, l-UPF, or a Visited UPF, V-UPF. A further aspect of the invention relates to a method performed by a user plane node for Small Data Transmission, SDT, in a communications network. The method comprises receiving at a user plane node from a session management node, rules for SDT data handling, particularly wherein the rules are for Mobile Terminated SDT, MT-SDT, and particularly wherein the rules are transmitted as part of the N4 Session establishment or update procedure. In some embodiments, the method further comprises receiving at the user plane node from the session management node an N4 Session establishment message indicating the user plane node to report DL data size. In some embodiments, the method further comprises receiving at the user plane node from the session management node an indication of support for MT-SDT for the PDll session. In some embodiments, the method further comprises receiving at the user plane node from the session management node, DL data size information when sending Data Notification, and wherein the session management node includes the DL data size information in the Namf MT EnableUEReachability message to the access and mobility management node, particularly wherein the DL data size information is a DL data size parameter or a DL data size flag indicating that the DL data size crossed a threshold configured in the session management node. In some embodiments, the radio access network node is a New Radio - Radio Access Network, NG- RAN, the access and mobility management node is an Access and Mobility Management Function, AMF, the session management node is a Session Management Function, SMF, the user plane node is a User Plane Function, UPF, particularly wherein the SMF is an Intermediate SMF, l-SMF, or a Visited SMF, V-SMF, and particularly wherein the UPF is an Intermediate UPF, l-UPF, or a Visited UPF, V-UPF.

[0016] In some embodiments, the radio access network node is a Radio Access Network (RAN). In some embodiments, the user plane node is a User Plane Function (UPF). In some embodiments, the access and mobility management node is an Access and Mobility Management Function (AMF). In some embodiments, the session management node is a Session Management Function (SMF).

[0017] Advantageously, the solution disclosed herein enables the delivery of DL data size to NG- RAN even when the current UPF does not support SDT such without major updates in the 5G system.

[0018] Further advantageously, the solution disclosed herein considers the data buffering in CN for RRCJNACTIVE and the setting of the MT-SDT flag in the Paging message from RAN based on buffered data size to apply MT-SDT paging. Further advantageously, the solution disclosed herein enables the 5G CN to provide the DL data size info to RAN for the paging procedure.

[0019] Further advantageously, the solution disclosed herein enables the 5G CN to provide the DL data size information to the RAN, especially when the current UPF does not support DL data size handling.

[0020] Additional objectives, features and advantages of the concepts disclosed herein will be apparent from the following description, claims and drawings, or may be learned by practice of the described technologies and concepts as set forth herein."

[0021] BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to best describe the manner in which the disclosed concepts may be implemented, as well as define other objects, advantages and features of the disclosure, a more particular description is provided below and is illustrated in the appended drawings. Understanding that these drawings depict only exemplary embodiments of the invention and are not therefore to be considered to be limiting in scope, the examples will be described and explained with additional specificity and detail through the use of the accompanying drawings.

[0023] Figure 1 illustrates an example networked system in accordance with particular embodiments of the solution described herein.

[0024] Figure 2 illustrates an example signaling diagram showing a procedure according to particular embodiments of the solution described herein.

[0025] Figure 3 illustrates an example signaling diagram showing a procedure according to particular embodiments of the solution described herein.

[0026] Figure 4 illustrates an example flowchart showing a method performed by a mobile network node according to particular embodiments of the solution described herein.

[0027] Figure 5 illustrates an example flowchart showing a method performed by a mobile network node according to particular embodiments of the solution described herein.

[0028] Figure 6 illustrates an example flowchart showing a method performed by a mobile network node according to particular embodiments of the solution described herein. Figure 7 illustrates an example flowchart showing a method performed by a mobile network node according to particular embodiments of the solution described herein.

[0029] Figure 8 illustrates an example block diagram of a mobile network node configured in accordance with particular embodiments of the solution described herein.

[0030] Figure 9 illustrates an example block diagram of a mobile network node configured in accordance with particular embodiments of the solution described herein.

[0031] Figure 10 illustrates an example block diagram of a mobile network node configured in accordance with particular embodiments of the solution described herein.

[0032] Figure 11 illustrates an example block diagram of a mobile network node configured in accordance with particular embodiments of the solution described herein.

[0033] Figure 12 illustrates an example signaling diagram showing a procedure according to particular embodiments of the solution described herein.

[0034] Figure 13 illustrates an example block diagram of a virtualized environment.

[0035] DETAILED DESCRIPTION

[0036] The invention will now be described in detail hereinafter with reference to the accompanying drawings, in which examples of embodiments or implementations of the invention are shown. The invention may, however, be embodied or implemented in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of present invention to those skilled in the art. It should also be noted that these embodiments are not mutually exclusive. Components from one embodiment may be tacitly assumed to be present / used in another embodiment. These embodiments of the disclosed subject matter are presented as teaching examples and are not to be construed as limiting the scope of the disclosed subject matter. For example, certain details of the described embodiments may be modified, omitted, or expanded upon without departing from the scope of the described subject matter.

[0037] The example embodiments described herein arise in the context of a telecommunications network, including but not limited to a telecommunications network that conforms to and / or otherwise incorporates aspects of a fifth generation (5G) architecture. Figure 1 is an example networked system 100 in accordance with example embodiments of the present disclosure. Figure 1 specifically illustrates User Equipment (UE) 101 , which may be in communication with a (Radio) Access Network (RAN) 102 and Access and Mobility Management Function (AMF) 106 and User Plane Function (UPF) 103. The AMF 106 may, in turn, be in communication with core network services including Session Management Function (SMF) 107 and Policy Control Function (PCF) 111. The core network services may also be in communication with an Application Server / Application Function (AS / AF) 113. Other networked services also include Network Slice Selection Function (NSSF) 108, Authentication Server Function (AUSF) 105, User Data Management (UDM) 112, Network Exposure Function (NEF) 109, Network Repository Function (NRF) 110 and Data Network (DN) 104. In some example implementations of embodiments of the present disclosure, each one of the entities in the networked system 100 are considered to be a Network Function (NF). One or more additional instances of the NFs may be incorporated into the networked system.

[0038] The solution described herein aims to enable UPF insertion, selection or reselection for SDT scenarios.

[0039] This disclosure provides a method for Small Data Transmission, SDT, in a communications network. The method comprises transmitting from a radio access network node to a access and mobility management node an indication that at least one of a PDU session and / or a QoS flow are subject to SDT, wherein the PDU session is identified by a PDU session ID, and / or wherein the QoS flow is identified by a QoS Flow Identifier, QFI; transmitting from the access and mobility management node to a session management node a request including an indication of the PDU sessions and / or QoS flows subject to SDT, particularly wherein the indication is based on the received information for SDT from the radio access network node or local policy, and particularly wherein the request is a Nsmf PDUSession UpdateSMContext Request; inserting, selecting or reselecting at the session management node a user plane node that supports SDT, particularly if the current user plane node does not support SDT; and transmitting from the session management node to the radio access network node via the access and mobility management node, N3 tunnel information parameters associated with the selected user plane node. In some embodiments, the method further comprises transmitting from the session management node to the user plane node rules for SDT data handling, particularly wherein the rules are for Mobile Terminated SDT, MT-SDT, and particularly wherein the rules are transmitted as part of the N4 Session establishment or update procedure. In some embodiments, the method further comprises transmitting from the session management node to the user plane node an N4 Session establishment message indicating the user plane node to report DL data size. In some embodiments, the method further comprises transmitting from the session management node to the user plane node an indication of support for MT-SDT for the PDU session. In some embodiments, the indication from the radio access network node to the access and mobility management node is transmitted in a N2 MT Communication Handling request message. In some embodiments, the method further comprises sending from the access and mobility management node to the radio access network node, a N2 MT Communication Handling response message, particularly wherein the response message indicates that the access and mobility management node acknowledges the request or that the access and mobility management node has taken the request into account. In some embodiments, the access and mobility management node provides to the radio access network node the N3 tunnel information parameters received from the session management node in a N2 MT Communication Handling response message or triggers a separate PDU Session Resource Modify procedure to update the N3 tunnel information in the radio access network node. In some embodiments, the access and mobility management node provides to the radio access network node an indication of support for MT-SDT for the PDU session, particularly based on an indication from the session management node. In some embodiments, the method further comprises providing from the user plane node to the session management node, DL data size information when sending Data Notification, and wherein the session management node includes the DL data size information in the Namf MT EnableUEReachability message to the access and mobility management node, particularly wherein the DL data size information is a DL data size parameter or a DL data size flag indicating that the DL data size crossed a threshold configured in the session management node. In some embodiments, the access and mobility management node includes the DL data size information in the N2 DL Data Notification message to the radio access network node, if the DL data size information is provided by the session management node to the access and mobility management node. In some embodiments, the method further comprises performing at the radio access network node, RAN paging towards the UE based on the parameters provided by the access and mobility management node and setting at the radio access network node the MT-SDT flag in the paging message if the DL data size is provided, wherein the MS-SDT flag is set if the DL data size crossed a threshold or a DL data size flag is provided from the session management node. In some embodiments, If the UL NG-U UP TNL Information IE is included in the MT COMMUNICATION HANDLING RESPONSE message, the radio access network node shall update the new user plane node endpoint of the NG-U transport bearer information, for delivery of LIL PDlls to the session management node for the indicated QoS flows. In some embodiments, the method further incudes: determining at an radio access network node, an eDRX cycle value for a User Equipment, UE, in RRCJNACTIVE state; initiating at the radio access network node, a Connection Inactive procedure with Core Network, CN, based Mobile Terminated, MT, communication handling; and transmitting from the radio access network node to the access and mobility management node, a N2 MT Communication Handling request message, wherein the request message indicates the UE's transition to RRCJNACTIVE state and provides the eDRX cycle value for the RRCJNACTIVE state. In some embodiments, the radio access network node is a New Radio - Radio Access Network, NG-RAN, the access and mobility management node is an Access and Mobility Management Function, AMF, the session management node is a Session Management Function, SMF, the user plane node is a User Plane Function, UPF, particularly wherein the SMF is an Intermediate SMF, l-SMF, or a Visited SMF, V-SMF, and particularly wherein the UPF is an Intermediate UPF, l-UPF, or a Visited UPF, V-UPF.

[0040] This disclosure also provides mobile network nodes, particularly a radio access network node (102, 800), a user plane node (103, 1100), an access and mobility management node (106, 900), a session management node (107, 1000) configured to perform the respective methods as described herein. In some embodiments, the radio access network node is a Radio Access Network (RAN) 102, a NR-RAN (New Radio RAN) 102 or a NG-RAN (Next Generation RAN) 102. In some embodiments, the user plane node is a User Plane Function (UPF) 103. In some embodiments, the access and mobility management node is an Access and Mobility Management Function (AMF) 106. In some embodiments, the session management node is a Session Management Function (SMF) 107.

[0041] This disclosure also provides the corresponding computer program and computer program products comprising code, for example in the form of a computer program, that when run on processing circuitry of the mobile network nodes causes the mobile network nodes to perform the disclosed methods.

[0042] Advantageously, the solution disclosed herein enables the delivery of DL data size to NG- RAN even when the current UPF does not support SDT such without major updates in the 5G system.

[0043] Further advantageously, the solution disclosed herein considers the data buffering in CN for RRCJNACTIVE and the setting of the MT-SDT flag in the Paging message from RAN based on buffered data size to apply MT-SDT paging. Further advantageously, the solution disclosed herein enables the 5G CN to provide the DL data size info to RAN for the paging procedure.

[0044] Further advantageously, the solution disclosed herein enables the 5G CN to provide the DL data size information to the RAN, especially when the current UPF does not support DL data size handling.

[0045] The solution and the features comprised therein are further described in what follows.

[0046] The solution disclosed herein enables to introduce l-UPF (re-)selection function based on the following:

[0047] NG-RAN indicates the PDU session / QoS flows that may be subject to SDT

[0048] AMF pass the SDT info to SMF

[0049] SMF may insert or reselect a l-UPF with SDT handling capability.

[0050] SMF / UPF provides the new N3 user tunnel info (of the l-UPF) back to NG-RAN.

[0051] That is, to introduce l-UPF selection function during the NG-RAN initiated Connection Inactive procedure with CN based MT communication handling procedure.

[0052] Hereinafter, drawings showing examples of embodiments of the solution are described in detail.

[0053] Figure 2 is a signaling diagram illustrating a procedure for Small Data Transmission (SDT) in a communications network. The procedure is performed by a radio access network node (102, 800), a user plane node (103, 1100), an access and mobility management node (106, 900), and a session management node (107, 1000). In some embodiments, the radio access network node is a Radio Access Network (RAN) 102, a NR-RAN (New Radio RAN) 102 or a NG-RAN (Next Generation RAN) 102. In some embodiments, the user plane node is a User Plane Function (UPF) 103. In some embodiments, the access and mobility management node is an Access and Mobility Management Function (AMF) 106. In some embodiments, the session management node is a Session Management Function (SMF) 107.

[0054] This procedure relates to Connection Inactive procedure with CN based MT communication handling and may be initiated by the serving NG-RAN node when CN based mobile terminating (MT) communication handling is requested for a UE that is configured with eDRX cycle value longer than 10.24 seconds for RRCJNACTIVE state and has at least one PDU session with active user plane. In step 0, the LIE is registered in the network with negotiated eDRX parameters for CM-IDLE state and is in CM-CONNECTED with RRC_CONNECTED state. The AMF provides the eDRX cycle value for CM-IDLE state to NG-RAN as part of the RRC Inactive Assistance Information.

[0055] In step 1 , NG-RAN determines eDRX cycle value for LIE in RRCJNACTIVE state and decides to initiate Connection Inactive with CN based MT communication handling.

[0056] In step 1 a, optionally the NG-RAN may initiate state transition from RRC_CONNECTED to RRCJNACTIVE with RRC configuring eDRX value. The NG-RAN may send the request in step 2 towards CN immediately following step 1a or the NG-RAN may delay this request towards CN.

[0057] In step 2, either immediately following step 1a or after having delayed the request for NG- RAN based on implementation, the NG-RAN sends N2 MT Communication Handling request message to AMF indicating the LIE is transitioning to RRCJNACTIVE state. The CN takes the NG-RAN request into consideration and handles MT communication. The NG-RAN also provides the eDRX cycle value for RRCJNACTIVE to AMF. The NG-RAN provides the PDll session IDs, and optionally the QFIs with indications that these PDU sessions / QoS flows are subject to SDT data.

[0058] If the NG-RAN receives DL NAS message and the LIE is in RRCJNACTIVE with RRC configured eDRX cycle and is considered not reachable, NG-RAN indicates to the AMF a NAS non-delivery and then initiates for the CN to handle mobile terminated (MT) communication.

[0059] In step 3, for each of the PDU sessions with user plane resources have been activated, the AMF invokes Nsmf PDUSession UpdateSMContext Request (PDU Session ID, Cause, Operation type, User Location Information, Age of Location Information, N2 SM Information (Secondary RAT usage data), CN based MT handling indication) towards SMF. The Operation Type is set to a value that indicates to stop user plane DL data transmissions towards the UE and enable data buffering. The AMF may provide indications on the PDU sessions / QFIs that are subject to SDT data handling (e.g. based on received information for SDT from NG-RAN in step 2 or local policy). The SMF starts data buffering for MT data if the data buffering is handled in SMF.

[0060] In step 4, if data buffering is handled in the UPF, the SMF updates the UPF with proper rules for MT data handling. If AMF provides information related to SDT, the SMF may decides to insert / re-select a l-UPF that supports SDT handling (e.g. provides DL data size to SMF when MT data comes) if the current UPF does not support the SDT handling. If new I-IIPF is selected, the SMF triggers the N4 Session establishment procedure towards the new l-UPF indicating the need of reporting DL data size and update current UPF with new tunnel information.

[0061] In step 5, the SMF sends the Nsmf PDUSession UpdateSMContext response. If new l-UPF is selected, the SMF provides all information for the user plane via the new l-UPF. The SMF provides the indication of support for MT-SDT for the PDU session.

[0062] In step 6, the AMF sends N2 MT Communication Handling response message to NG-RAN acknowledging the NG-RAN request and indicating the AMF has taken the NG-RAN request into account. The AMF considers the UE is in CM-CONNECTED with RRCJNACTIVE state. The AMF provides the new N3 tunnel information parameters received in step 5 in the N2 MT Communication Handling response message or triggers a separate PDU Session Resource Modify procedure to update the new N3 tunnel information received in step 5. The AMF may also provide the indication of support for MT-SDT for the PDU session, based on indication from SMF.

[0063] In step 7, if the UE connection is not released as specified in step 1a, the NG-RAN initiates state transition from RRC_CONNECTED to RRCJNACTIVE with RRC configuring the eDRX cycle value.

[0064] Figure 3 is a signaling diagram illustrating a procedure for Small Data Transmission (SDT) in a communications network. The procedure is performed by a radio access network node (102, 800), a user plane node (103, 1100), an access and mobility management node (106, 900), and a session management node (107, 1000). In some embodiments, the radio access network node is a Radio Access Network (RAN) 102, a NR-RAN (New Radio RAN) 102 or a NG-RAN (Next Generation RAN) 102. In some embodiments, the user plane node is a User Plane Function (UPF) 103. In some embodiments, the access and mobility management node is an Access and Mobility Management Function (AMF) 106. In some embodiments, the session management node is a Session Management Function (SMF) 107.

[0065] The procedure is related to Network Triggered Connection Resume in RRCJNACTIVE with CN based MT communication handling. When the UE is in CM-CONNECTED with RRCJNACTIVE state with CN based mobile terminating (MT) communication handling, high latency communication is applied. This procedure may be triggered by MT data, or a N1 procedure from SMF and UPF. When the procedure is triggered by other NFs (e.g. SMSF, LMF, GMLC), the UPF (or SMF) in the following figure should be replaced by the respective NF (the corresponding service operations used by other NFs when they communicate with AMF may also be different from the service operations used by SMF / UPF).

[0066] During the procedure, the NG-RAN (i.e., gNB) performs RAN paging towards the UE based on the N2 message from the AMF in order to trigger the UE triggered Connection Resume procedure.

[0067] In step 1 a, when downlink data is received and the SMF / UPF is requested to perform buffering, the UPF / SMF checks with AMF for the possibility of data delivery, this step includes the following:

[0068] The UPF that supports the provision of DL data size and instructed by SMF to report DL data size, provides also the DL data size information when sending Data Notification to SMF.

[0069] In the Namf MT EnableUEReachability the SMF may also send the PPI, the ARP and the 5QI, and / or QFI of the QoS Flow of the PDU Session which triggered the request for paging policy differentiation. The SMF also include the DL data size parameter if it’s provided. Note, the SMF may provide the exact DL data size, or only provide when it is under certain threshold based on configuration.

[0070] If the SMF, while waiting for UE triggered Connection Resume indication or a reject response (with Estimated Maximum Wait time) from the AMF, receives any additional Data Notification message due to additional data packets for another QoS Flow associated with a higher priority (i.e. ARP priority level) than the priority indicated to the AMF in the previous Namf MT EnableUEReachability, or the SMF derive a different Paging Policy Indicator according to the additional Data Notification, the SMF invokes a new Namf MT EnableUEReachability indicating the higher priority or different Paging Policy Indicator to the AMF. The information contained in the new

[0071] Namf MT EnableUEReachability request overrides the information from the previous Namf MT EnableUEReachability request that is stored in the AMF. If the SMF receives any additional Data Notification messages due to additional data packets for another QoS Flow associated with same or lower priority than the priority indicated to the AMF in the previous Namf MT EnableUEReachability or if the SMF has sent the second

[0072] Namf MT EnableUEReachability message indicating the higher priority and receives additional downlink data packets for this UE, the SMF buffers these downlink data packets and does not send a new Namf MT EnableUEReachability meassage.

[0073] The AMF determines if the UE is reachable based on the stored eDRX cycle value for RRCJNACTIVE state provided by NG-RAN. If the UE is unreachable, the AMF stores the information received in the Namf MT EnableUEReachability request and provides the Estimated Maximum Wait time in the response message based on the eDRX cycle value for RRCJNACTIVE in AMF (steps 2-5 are postponed until the UE becomes reachable). If the UE is considered reachable, step 2 is executed immediately.

[0074] This handling is similar to CM-IDLE with eDRX. When the AMF provides the Estimated Maximum Wait time, it can consider the time needed for RRC level procedures (e.g. RRC RNA update procedure) when UE wakes up from the eDRX cycle.

[0075] In step 2, when the AMF determines that the UE is reachable, the AMF sends an N2 DL Data Notification message to NG-RAN with the request for the UE's RRC connection to be resumed. The AMF may include the following parameter(s) the PPI, the ARP and the 5QI, and / or QFI of the QoS Flow of the PDU Session ID in the N2 DL Data Notification message to trigger and enable RAN paging. If DL data size is provided by SMF in

[0076] Namf UE EnableUEReachability, AMF includes the parameter in the N2 DL Data Notification message.

[0077] In step 3, NG-RAN performs RAN paging towards the UE considering the parameters provided by the AMF. If DL data size is provided by AMF, the NG-RAN may set the MT-SDT flag in Paging message.

[0078] In step 4, when the UE receives RAN paging, it initiates the UE triggered Connection Resume procedure and NG-RAN notifies CN including the N2 Notification in step 3b. If MT- SDT flag is set in the Paging, the UE may perform the Connection Resume with SDT options.

[0079] In step 5, the UPF triggers downlink data delivery if there is any. The AMF sends downlink NAS messages if there is any.

[0080] Figure 12 is a signaling diagram illustrating a procedure for Small Data Transmission (SDT) in a communications network. The procedure is performed by a radio access network node (102, 800), and an access and mobility management node (106, 900). In some embodiments, the radio access network node is a Radio Access Network (RAN) 102, a NR- RAN (New Radio RAN) 102 or a NG-RAN (Next Generation RAN) 102. In some embodiments, the access and mobility management node is an Access and Mobility Management Function (AMF) 106.

[0081] This procedure relates to MT Communication Handling procedure. The purpose of the MT Communication Handling procedure is to request the AMF to activate or deactivate the CN based MT Communication handling for a LIE in RRCJNACTIVE state with extended DRX beyond 10.24 seconds. The procedure uses UE-associated signalling.

[0082] The NG-RAN node initiates the procedure by sending the MT COMMUNICATION HANDLING REQUEST message to the AMF.

[0083] If the 5GC Action IE is included in the MT COMMUNICATION HANDLING REQUEST message and set to 'HLCom Activate', the AMF shall activate MT communication handling.

[0084] If the 5GC Action IE is included in the MT COMMUNICATION HANDLING REQUEST message and set to 'HLCom Deactivate', the AMF shall deactivate MT communication handling.

[0085] If the NR Paging eDRX Cycle for RRC INACTIVE IE is included in the MT COMMUNICATION HANDLING REQUEST message, the AMF shall, if supported, take it into account when applying MT communication handling.

[0086] If the UL NG-U UP TNL Information IE is included in the MT COMMUNICATION HANDLING RESPONSE message, the NG-RAN shall update the new UPF endpoint of the NG-U transport bearer information, for delivery of UL PDUs to the SMF for the indicated QoS flows.

[0087] Regarding the MT COMMUNICATION HANDLING RESPONSE, this message is sent by the AMF to indicate that CN based MT Communication handling was successfully applied. The direction is from the AMF to the NG-RAN node. This message comprises the following Information Elements (IE):

[0088] Hereinafter, flowcharts showing examples of embodiments of the solution are described in detail. The embodiments correspond to methods performed by and involving a radio access network node (102, 800), a user plane node (103, 1100), an access and mobility management node (106, 900), a session management node (107, 1000).

[0089] Figure 4 is a flowchart illustrating a method performed by the radio access network node for Small Data Transmission, SDT, in a communications network.

[0090] In step S-401 , the radio access network node transmits to a access and mobility management node an indication that at least one of a PDU session and / or a QoS flow are subject to SDT, wherein the PDU session is identified by a PDU session ID, and / or wherein the QoS flow is identified by a QoS Flow Identifier, QFI.

[0091] In step S-402, the radio access network node receives from a session management node via the access and mobility management node, N3 tunnel information parameters associated with a selected user plane node by the session management node.

[0092] In some embodiments, the indication from the radio access network node to the access and mobility management node is transmitted in a N2 MT Communication Handling request message.

[0093] In some embodiments, the method further comprises sending from the access and mobility management node to the radio access network node, a N2 MT Communication Handling response message, particularly wherein the response message indicates that the access and mobility management node acknowledges the request or that the access and mobility management node has taken the request into account.

[0094] In some embodiments, the access and mobility management node provides to the radio access network node the N3 tunnel information parameters received from the session management node in a N2 MT Communication Handling response message or triggers a separate PDU Session Resource Modify procedure to update the N3 tunnel information in the radio access network node.

[0095] In some embodiments, the access and mobility management node provides to the radio access network node an indication of support for MT-SDT for the PDU session, particularly based on an indication from the session management node.

[0096] In some embodiments, the access and mobility management node includes the DL data size information in the N2 DL Data Notification message to the radio access network node, if the DL data size information is provided by the session management node to the access and mobility management node. In some embodiments, the method further comprises performing at the radio access network node, RAN paging towards the UE based on the parameters provided by the access and mobility management node and setting at the radio access network node the MT-SDT flag in the paging message if the DL data size is provided, wherein the MS-SDT flag is set if the DL data size crossed a threshold or a DL data size flag is provided from the session management node.

[0097] In some embodiments, If the LIL NG-ll UP TNL Information IE is included in the MT COMMUNICATION HANDLING RESPONSE message, the radio access network node shall update the new user plane node endpoint of the NG-U transport bearer information, for delivery of UL PDUs to the session management node for the indicated QoS flows.

[0098] In some embodiments, the method further incudes: determining at an radio access network node, an eDRX cycle value for a User Equipment, UE, in RRCJNACTIVE state; initiating at the radio access network node, a Connection Inactive procedure with Core Network, CN, based Mobile Terminated, MT, communication handling; and transmitting from the radio access network node to the access and mobility management node, a N2 MT Communication Handling request message, wherein the request message indicates the UE's transition to RRCJNACTIVE state and provides the eDRX cycle value for the RRC NACTIVE state.

[0099] In some embodiments, the radio access network node is a New Radio - Radio Access Network, NG-RAN, the access and mobility management node is an Access and Mobility Management Function, AMF, the session management node is a Session Management Function, SMF, the user plane node is a User Plane Function, UPF.

[0100] Figure 5 is a flowchart illustrating a method performed by the access and mobility management node for Small Data Transmission, SDT, in a communications network.

[0101] In step S-501 , the access and mobility management node receives from a radio access network node an indication that at least one of a PDU session and / or a QoS flow are subject to SDT, wherein the PDU session is identified by a PDU session ID, and / or wherein the QoS flow is identified by a QoS Flow Identifier, QFI.

[0102] In step S-502, the access and mobility management node transmits to a session management node a request including an indication of the PDU sessions and / or QoS flows subject to SDT, particularly wherein the indication is based on the received information for SDT from the radio access network node or local policy, and particularly wherein the request is a Nsmf PDUSession UpdateSMContext Request. In step S-503, the access and mobility management node transmits to the radio access network node via the access and mobility management node, N3 tunnel information parameters associated with a selected user plane node received from the session management node.

[0103] In some embodiments, the indication from the radio access network node to the access and mobility management node is transmitted in a N2 MT Communication Handling request message.

[0104] In some embodiments, the method further comprises sending from the access and mobility management node to the radio access network node, a N2 MT Communication Handling response message, particularly wherein the response message indicates that the access and mobility management node acknowledges the request or that the access and mobility management node has taken the request into account.

[0105] In some embodiments, the access and mobility management node provides to the radio access network node the N3 tunnel information parameters received from the session management node in a N2 MT Communication Handling response message or triggers a separate PDU Session Resource Modify procedure to update the N3 tunnel information in the radio access network node.

[0106] In some embodiments, the access and mobility management node provides to the radio access network node an indication of support for MT-SDT for the PDU session, particularly based on an indication from the session management node.

[0107] In some embodiments, the access and mobility management node includes the DL data size information in the N2 DL Data Notification message to the radio access network node, if the DL data size information is provided by the session management node to the access and mobility management node.

[0108] In some embodiments, the method further comprises performing at the radio access network node, RAN paging towards the UE based on the parameters provided by the access and mobility management node and setting at the radio access network node the MT-SDT flag in the paging message if the DL data size is provided, wherein the MS-SDT flag is set if the DL data size crossed a threshold or a DL data size flag is provided from the session management node.

[0109] In some embodiments, If the UL NG-U UP TNL Information IE is included in the MT COMMUNICATION HANDLING RESPONSE message, the radio access network node shall update the new user plane node endpoint of the NG-U transport bearer information, for delivery of LIL PDlls to the session management node for the indicated QoS flows.

[0110] In some embodiments, the method further incudes: determining at an radio access network node, an eDRX cycle value for a User Equipment, UE, in RRCJNACTIVE state; initiating at the radio access network node, a Connection Inactive procedure with Core Network, CN, based Mobile Terminated, MT, communication handling; and transmitting from the radio access network node to the access and mobility management node, a N2 MT Communication Handling request message, wherein the request message indicates the UE's transition to RRCJNACTIVE state and provides the eDRX cycle value for the RRC NACTIVE state.

[0111] In some embodiments, the radio access network node is a New Radio - Radio Access Network, NG-RAN, the access and mobility management node is an Access and Mobility Management Function, AMF, the session management node is a Session Management Function, SMF, the user plane node is a User Plane Function, UPF.

[0112] Figure 6 is a flowchart illustrating a method performed by the session management node for Small Data Transmission, SDT, in a communications network.

[0113] In step S-601 , the session management node receives from a access and mobility management node a request including an indication of the PDU sessions and / or QoS flows subject to SDT, particularly wherein the indication is based on the received information for SDT from the radio access network node or local policy, and particularly wherein the request is a Nsmf PDUSession UpdateSMContext Request.

[0114] In step S-602, the session management node Inserts, selects or reselects a user plane node that supports SDT, particularly if the current user plane node does not support SDT.

[0115] In step S-603, the session management node transmits to a radio access network node via the access and mobility management node, N3 tunnel information parameters associated with the selected user plane node.

[0116] In step S-604, the session management node transmits to the user plane node rules for SDT data handling, particularly wherein the rules are for Mobile Terminated SDT, MT-SDT, and particularly wherein the rules are transmitted as part of the N4 Session establishment or update procedure.

[0117] In step S-605, the session management node transmits to the user plane node an N4 Session establishment message indicating the user plane node to report DL data size. In step S-606, the session management node transmits to the user plane node an indication of support for MT-SDT for the PDll session.

[0118] In some embodiments, the method further comprises providing from the user plane node to the session management node, DL data size information when sending Data Notification, and wherein the session management node includes the DL data size information in the Namf MT EnableUEReachability message to the access and mobility management node, particularly wherein the DL data size information is a DL data size parameter or a DL data size flag indicating that the DL data size crossed a threshold configured in the session management node.

[0119] In some embodiments, the radio access network node is a New Radio - Radio Access Network, NG-RAN, the access and mobility management node is an Access and Mobility Management Function, AMF, the session management node is a Session Management Function, SMF, the user plane node is a User Plane Function, UPF.

[0120] Figure 7 is a flowchart illustrating a method performed by the user plane node for Small Data Transmission, SDT, in a communications network.

[0121] In step S-701 , the user plane node receives from a session management node rules for SDT data handling, particularly wherein the rules are for Mobile Terminated SDT, MT-SDT, and particularly wherein the rules are transmitted as part of the N4 Session establishment or update procedure.

[0122] In step S-702, the user plane node receives from a session management node rules for SDT data handling, particularly wherein the rules are for Mobile Terminated SDT, MT-SDT, and particularly wherein the rules are transmitted as part of the N4 Session establishment or update procedure.

[0123] In step S-703, the user plane node receives from a session management node rules for SDT data handling, particularly wherein the rules are for Mobile Terminated SDT, MT-SDT, and particularly wherein the rules are transmitted as part of the N4 Session establishment or update procedure.

[0124] In some embodiments, the method further comprises receiving at the user plane node from the session management node, DL data size information when sending Data Notification, and wherein the session management node includes the DL data size information in the Namf MT EnableUEReachability message to the access and mobility management node, particularly wherein the DL data size information is a DL data size parameter or a DL data size flag indicating that the DL data size crossed a threshold configured in the session management node.

[0125] In some embodiments, the radio access network node is a New Radio - Radio Access Network, NG-RAN, the access and mobility management node is an Access and Mobility Management Function, AMF, the session management node is a Session Management Function, SMF, the user plane node is a User Plane Function, UPF.

[0126] Figure 8 is a block diagram illustrating elements of a mobile network node 800 of a mobile communications network. In some embodiments, the mobile network node 800 is a RAN 102. As shown, the mobile network node may include network interface circuitry 801 (also referred to as a network interface) configured to provide communications with other nodes of the core network and / or the network. The mobile network node may also include a processing circuitry 802 (also referred to as a processor) coupled to the network interface circuitry, and memory circuitry 803 (also referred to as memory) coupled to the processing circuitry. The memory circuitry 803 may include computer readable program code that when executed by the processing circuitry 802 causes the processing circuitry to perform operations according to embodiments disclosed herein. According to other embodiments, processing circuitry 802 may be defined to include memory so that a separate memory circuitry is not required. As discussed herein, operations of the mobile network node may be performed by processing circuitry 802 and / or network interface circuitry 801 . For example, processing circuitry 802 may control network interface circuitry 801 to transmit communications through network interface circuitry 801 to one or more other network nodes and / or to receive communications through network interface circuitry from one or more other network nodes. Moreover, modules may be stored in memory 803, and these modules may provide instructions so that when instructions of a module are executed by processing circuitry 802, processing circuitry 802 performs respective operations (e.g., operations discussed below with respect to Example Embodiments relating to core network nodes).

[0127] Figure 9 is a block diagram illustrating elements of a mobile network node 900 of a mobile communications network. In some embodiments, the mobile network node 900 is an AMF 106. As shown, the mobile network node may include network interface circuitry 901 (also referred to as a network interface) configured to provide communications with other nodes of the core network and / or the network. The mobile network node may also include a processing circuitry 902 (also referred to as a processor) coupled to the network interface circuitry, and memory circuitry 903 (also referred to as memory) coupled to the processing circuitry. The memory circuitry 903 may include computer readable program code that when executed by the processing circuitry 902 causes the processing circuitry to perform operations according to embodiments disclosed herein. According to other embodiments, processing circuitry 902 may be defined to include memory so that a separate memory circuitry is not required. As discussed herein, operations of the mobile network node may be performed by processing circuitry 902 and / or network interface circuitry 901 . For example, processing circuitry 902 may control network interface circuitry 901 to transmit communications through network interface circuitry 901 to one or more other network nodes and / or to receive communications through network interface circuitry from one or more other network nodes. Moreover, modules may be stored in memory 903, and these modules may provide instructions so that when instructions of a module are executed by processing circuitry 902, processing circuitry 902 performs respective operations (e.g., operations discussed below with respect to Example Embodiments relating to core network nodes).

[0128] Figure 10 is a block diagram illustrating elements of a mobile network node 1000 of a mobile communications network. In some embodiments, the mobile network node 1000 is an SMF 107. As shown, the mobile network node may include network interface circuitry 1001 (also referred to as a network interface) configured to provide communications with other nodes of the core network and / or the network. The mobile network node may also include a processing circuitry 1002 (also referred to as a processor) coupled to the network interface circuitry, and memory circuitry 1003 (also referred to as memory) coupled to the processing circuitry. The memory circuitry 1003 may include computer readable program code that when executed by the processing circuitry 1002 causes the processing circuitry to perform operations according to embodiments disclosed herein. According to other embodiments, processing circuitry 1002 may be defined to include memory so that a separate memory circuitry is not required. As discussed herein, operations of the mobile network node may be performed by processing circuitry 1002 and / or network interface circuitry 1001 . For example, processing circuitry 1002 may control network interface circuitry 1001 to transmit communications through network interface circuitry 1001 to one or more other network nodes and / or to receive communications through network interface circuitry from one or more other network nodes. Moreover, modules may be stored in memory 1003, and these modules may provide instructions so that when instructions of a module are executed by processing circuitry 1002, processing circuitry 1002 performs respective operations (e.g., operations discussed below with respect to Example Embodiments relating to core network nodes). - T1 -

[0129] Figure 11 is a block diagram illustrating elements of a mobile network node 1100 of a mobile communications network. In some embodiments, the mobile network node 1100 is a UPF 103. As shown, the mobile network node may include network interface circuitry 1101 (also referred to as a network interface) configured to provide communications with other nodes of the core network and / or the network. The mobile network node may also include a processing circuitry 1102 (also referred to as a processor) coupled to the network interface circuitry, and memory circuitry 1103 (also referred to as memory) coupled to the processing circuitry. The memory circuitry 1103 may include computer readable program code that when executed by the processing circuitry 1102 causes the processing circuitry to perform operations according to embodiments disclosed herein. According to other embodiments, processing circuitry 1102 may be defined to include memory so that a separate memory circuitry is not required. As discussed herein, operations of the mobile network node may be performed by processing circuitry 1102 and / or network interface circuitry 1101. For example, processing circuitry 1102 may control network interface circuitry 1101 to transmit communications through network interface circuitry 1101 to one or more other network nodes and / or to receive communications through network interface circuitry from one or more other network nodes. Moreover, modules may be stored in memory 1103, and these modules may provide instructions so that when instructions of a module are executed by processing circuitry 1102, processing circuitry 1102 performs respective operations (e.g., operations discussed below with respect to Example Embodiments relating to core network nodes).

[0130] Figure 13 is a block diagram illustrating a virtualization environment 1300 in which functions implemented by some embodiments may be virtualized. In the present context, virtualizing means creating virtual versions of apparatuses or devices which may include virtualizing hardware platforms, storage devices and networking resources. As used herein, virtualization can be applied to any device described herein, or components thereof, and relates to an implementation in which at least a portion of the functionality is implemented as one or more virtual components. Some or all of the functions described herein may be implemented as virtual components executed by one or more virtual machines (VMs) implemented in one or more virtual environments 1300 hosted by one or more of hardware nodes, such as a hardware computing device that operates as a network node, UE, core network node, or host. Further, in embodiments in which the virtual node does not require radio connectivity (e.g., a core network node or host), then the node may be entirely virtualized. In some embodiments, the virtualization environment 1300 includes components defined by the O-RAN Alliance, such as an O-Cloud environment orchestrated by a Service Management and Orchestration Framework via an 0-2 interface.

[0131] Applications 1302 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment Q400 to implement some of the features, functions, and / or benefits of some of the embodiments disclosed herein.

[0132] Hardware 1304 includes processing circuitry, memory that stores software and / or instructions executable by hardware processing circuitry, and / or other hardware devices as described herein, such as a network interface, input / output interface, and so forth. Software may be executed by the processing circuitry to instantiate one or more virtualization layers 1306 (also referred to as hypervisors or virtual machine monitors (VMMs)), provide VMs 1308a and 1308b (one or more of which may be generally referred to as VMs 1308), and / or perform any of the functions, features and / or benefits described in relation with some embodiments described herein. The virtualization layer 1306 may present a virtual operating platform that appears like networking hardware to the VMs 1308.

[0133] The VMs 1308 comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by a corresponding virtualization layer 1306. Different embodiments of the instance of a virtual appliance 1302 may be implemented on one or more of VMs 1308, and the implementations may be made in different ways. Virtualization of the hardware is in some contexts referred to as network function virtualization (NFV). NFV may be used to consolidate many network equipment types onto industry standard high volume server hardware, physical switches, and physical storage, which can be located in data centers, and customer premise equipment.

[0134] In the context of NFV, a VM 1308 may be a software implementation of a physical machine that runs programs as if they were executing on a physical, non-virtualized machine. Each of the VMs 1308, and that part of hardware 1304 that executes that VM, be it hardware dedicated to that VM and / or hardware shared by that VM with others of the VMs, forms separate virtual network elements. Still in the context of NFV, a virtual network function is responsible for handling specific network functions that run in one or more VMs 1308 on top of the hardware 1304 and corresponds to the application 1302.

[0135] Hardware 1304 may be implemented in a standalone network node with generic or specific components. Hardware 1304 may implement some functions via virtualization. Alternatively, hardware 1304 may be part of a larger cluster of hardware (e.g. such as in a data center or CPE) where many hardware nodes work together and are managed via management and orchestration 1310, which, among others, oversees lifecycle management of applications 1302. In some embodiments, hardware 1304 is coupled to one or more radio units that each include one or more transmitters and one or more receivers that may be coupled to one or more antennas. Radio units may communicate directly with other hardware nodes via one or more appropriate network interfaces and may be used in combination with the virtual components to provide a virtual node with radio capabilities, such as a radio access node or a base station. In some embodiments, some signaling can be provided with the use of a control system 1312 which may alternatively be used for communication between hardware nodes and radio units.

[0136] Embodiments within the scope of the present invention may also include computer-readable media for carrying or having computer-executable instructions or data structures stored thereon. Such computer-readable media can be any available media that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, such tangible computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to carry or store desired program code means in the form of computer-executable instructions or data structures. When information is transferred or provided over a network or another communications connection (either hardwired, wireless, or combination thereof) to a computer, the computer properly views the connection as a computer-readable medium. Thus, any such connection is properly termed a computer- readable medium. Combinations of the above should also be included within the scope of the tangible computer-readable media.

[0137] Computer-executable instructions include, for example, instructions and data which cause a general purpose computer, special purpose computer, or special purpose processing device to perform a certain function or group of functions. Computer-executable instructions also include program modules that are executed by computers in standalone or network environments. Generally, program modules include routines, programs, objects, components, and data structures that perform particular tasks or implement particular abstract data types. Computer executable instructions, associated data structures, and program modules represent examples of the program code means for executing steps of the methods disclosed herein. The particular sequence of such executable instructions or associated data structures represent examples of corresponding acts for implementing the functions described in such steps. Those of skill in the art will appreciate that other embodiments of the invention may be practiced in network computing environments with many types of computer system configurations, including personal computers, hand-held devices, multi-processor systems, microprocessor-based or programmable consumer electronics, network PCs, minicomputers, mainframe computers, and the like. Embodiments may also be practiced in distributed computing environments where tasks are performed by local and remote processing devices that are linked (either by hardwired links, wireless links, or by a combination thereof) through a communications network. In a distributed computing environment, program modules may be located in both local and remote memory storage devices.

[0138] Communication at various stages of the described system can be performed through a local area network, a token ring network, the Internet, a corporate intranet, 802.11 series wireless signals, fiber-optic network, radio or microwave transmission, etc. Although the underlying communication technology may change, the fundamental principles described herein are still applicable.

[0139] The various embodiments described above are provided by way of illustration only and should not be construed to limit the invention. For example, the principles herein may be applied to any remotely controlled device. Further, those of skill in the art will recognize that communication between the remote the remotely controlled device need not be limited to communication over a local area network but can include communication over infrared channels, Bluetooth or any other suitable communication interface. Those skilled in the art will readily recognize various modifications and changes that may be made to the present invention without following the example embodiments and applications illustrated and described herein, and without departing from the scope of the present disclosure.

[0140] The terminology used herein is for the purpose of describing various embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "includes," "including," "comprises," and "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, or components, and combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, or components, and combinations thereof. Further, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to ""a / an / the element, apparatus, component, means, module, step, etc."" are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, module, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.

Claims

CLAIMS1 . A method for Small Data Transmission, SDT, in a communications network, the method comprising: transmitting from a radio access network node to an access and mobility management node an indication that at least one of a Packet Data Unit, PDU, session and / or a Quality of Service, QoS, flow are subject to SDT, wherein the PDU session is identified by a PDU session Identifier, PDU session ID, and / or wherein the QoS flow is identified by a QoS Flow Identifier, QFI; transmitting from the access and mobility management node to a session management node a request including an indication of the PDU sessions and / or QoS flows subject to SDT, particularly wherein the indication is based on the received information for SDT from the radio access network node or local policy, and particularly wherein the request is a Nsmf PDUSession UpdateSMContext Request; inserting, selecting or reselecting at the session management node a user plane node that supports SDT, particularly if the current user plane node does not support SDT ; and transmitting from the session management node to the radio access network node via the access and mobility management node, N3 tunnel information parameters associated with the selected user plane node.

2. The method of claim 1 , further comprising: transmitting from the session management node to the user plane node rules for SDT data handling, particularly wherein the rules are for Mobile Terminated SDT, MT-SDT, and particularly wherein the rules are transmitted as part of the N4 Session establishment or update procedure.

3. The method of any one of claims from claim 1 to claim 2, further comprising: transmitting from the session management node to the user plane node an N4 Session establishment message indicating the user plane node to report DL data size.

4. The method of any one of claims from claim 1 to claim 3, further comprising:transmitting from the session management node to the user plane node an indication of support for MT-SDT for the PDll session.

5. The method of any one of claims from claim 1 to claim 4, wherein the indication from the radio access network node to the access and mobility management node is transmitted in a N2 MT Communication Handling request message.

6. The method of any one of claims from claim 1 to claim 5, wherein the method further comprises sending from the access and mobility management node to the radio access network node, a N2 MT Communication Handling response message, particularly wherein the response message indicates that the access and mobility management node acknowledges the request or that the access and mobility management node has taken the request into account.

7. The method of any one of claims from claim 1 to claim 6, wherein the access and mobility management node provides to the radio access network node the N3 tunnel information parameters received from the session management node in a N2 MT Communication Handling response message or triggers a separate PDU Session Resource Modify procedure to update the N3 tunnel information in the radio access network node.

8. The method of any one of claims from claim 1 to claim 7, wherein the access and mobility management node provides to the radio access network node an indication of support for MT-SDT for the PDU session, particularly based on an indication from the session management node.

9. The method of any one of claims from claim 1 to claim 8, wherein the method further comprises providing from the user plane node to the session management node, DL data size information when sending Data Notification, and wherein the session management node includes the DL data size information in the Namf MT EnableUEReachability message to the access and mobility management node, particularly wherein the DL data size information is a DL data size parameter or a DL data size flag indicating that the DL data size crossed a threshold configured in the session management node.

10. The method of any one of claims from claim 1 to claim 9, wherein the access and mobility management node includes the DL data size information in the N2 DL Data Notification message to the radio access network node, if the DL data size information is provided by the session management node to the access and mobility management node.11 . The method of any one of claims from claim 1 to claim 10, wherein the method further comprises performing at the radio access network node, RAN paging towards the UE based on the parameters provided by the access and mobility management node and setting at the radio access network node the MT-SDT flag in the paging message if the DL data size is provided, wherein the MS-SDT flag is set if the DL data size crossed a threshold or a DL data size flag is provided from the session management node.

12. The method of any one of claims from claim 1 to claim 11 , wherein If the UL NG-U UP TNL Information IE is included in the MT COMMUNICATION HANDLING RESPONSE message, the radio access network node shall update the new user plane node endpoint of the NG-U transport bearer information, for delivery of UL PDUs to the session management node for the indicated QoS flows.

13. The method of any one of claims from claim 1 to claim 12, wherein the method further incudes: determining at an radio access network node, an eDRX cycle value for a User Equipment, UE, in RRCJNACTIVE state; initiating at the radio access network node, a Connection Inactive procedure with Core Network, CN, based Mobile Terminated, MT, communication handling; and transmitting from the radio access network node to the access and mobility management node, a N2 MT Communication Handling request message, wherein the request message indicates the UE's transition to RRCJNACTIVE state and provides the eDRX cycle value for the RRCJNACTIVE state.

14. The method of any one of claims from claim 1 to claim 13, wherein the radio access network node is a New Radio - Radio Access Network, NG-RAN, the access and mobility management node is an Access and Mobility Management Function, AMF, the session management node is a Session Management Function, SMF, the user plane node is a User Plane Function, UPF, particularly wherein the SMF is an Intermediate SMF, l-SMF, or a Visited SMF, V-SMF, and particularly wherein the UPF is an Intermediate UPF, l-UPF, or a Visited UPF, V-UPF.

15. A method performed by a radio access network node for Small Data Transmission, SDT, in a communications network, the method comprising: transmitting from a radio access network node to an access and mobility management node an indication that at least one of a Packet Data Unit, PDU, session and / or a Quality of Service, QoS, flow are subject to SDT, wherein the PDU session is identified by a PDU session Identifier, PDU session ID, and / or wherein the QoS flow is identified by a QoS Flow Identifier, QFI; andreceiving at the radio access network node from a session management node via the access and mobility management node, N3 tunnel information parameters associated with a selected user plane node by the session management node.

16. The method of claim 15, wherein the indication from the radio access network node to the access and mobility management node is transmitted in a N2 MT Communication Handling request message.

17. The method of any one of claims from claim 15 to claim 16, wherein the method further comprises sending from the access and mobility management node to the radio access network node, a N2 MT Communication Handling response message, particularly wherein the response message indicates that the access and mobility management node acknowledges the request or that the access and mobility management node has taken the request into account.

18. The method of any one of claims from claim 15 to claim 17, wherein the access and mobility management node provides to the radio access network node the N3 tunnel information parameters received from the session management node in a N2 MT Communication Handling response message or triggers a separate PDU Session Resource Modify procedure to update the N3 tunnel information in the radio access network node.

19. The method of any one of claims from claim 15 to claim 18, wherein the access and mobility management node provides to the radio access network node an indication of support for MT-SDT for the PDU session, particularly based on an indication from the session management node.

20. The method of any one of claims from claim 15 to claim 19, wherein the access and mobility management node includes the DL data size information in the N2 DL Data Notification message to the radio access network node, if the DL data size information is provided by the session management node to the access and mobility management node.21 . The method of any one of claims from claim 15 to claim 20, wherein the method further comprises performing at the radio access network node, RAN paging towards the UE based on the parameters provided by the access and mobility management node and setting at the radio access network node the MT-SDT flag in the paging message if the DL data size is provided, wherein the MS-SDT flag is set if the DL data size crossed a threshold or a DL data size flag is provided from the session management node.

22. The method of any one of claims from claim 15 to claim 21 , wherein If the LIL NG-ll UP TNL Information IE is included in the MT COMMUNICATION HANDLING RESPONSE message, the radio access network node shall update the new user plane node endpoint of the NG-U transport bearer information, for delivery of UL PDUs to the session management node for the indicated QoS flows.

23. The method of any one of claims from claim 15 to claim 22, wherein the method further incudes: determining at an radio access network node, an eDRX cycle value for a User Equipment, UE, in RRCJNACTIVE state; initiating at the radio access network node, a Connection Inactive procedure with Core Network, CN, based Mobile Terminated, MT, communication handling; and transmitting from the radio access network node to the access and mobility management node, a N2 MT Communication Handling request message, wherein the request message indicates the UE's transition to RRCJNACTIVE state and provides the eDRX cycle value for the RRCJNACTIVE state.

24. The method of any one of claims from claim 15 to claim 23, wherein the radio access network node is a New Radio - Radio Access Network, NG-RAN, the access and mobility management node is an Access and Mobility Management Function, AMF, the session management node is a Session Management Function, SMF, the user plane node is a User Plane Function, UPF, particularly wherein the SMF is an Intermediate SMF, l-SMF, or a Visited SMF, V-SMF, and particularly wherein the UPF is an Intermediate UPF, l-UPF, or a Visited UPF, V-UPF.

25. A method performed by an access and mobility management node for Small Data Transmission, SDT, in a communications network, the method comprising: receiving at the access and mobility management node from a radio access network node an indication that at least one of a Packet Data Unit, PDU, session and / or a Quality of Service, QoS, flow are subject to SDT, wherein the PDU session is identified by a PDU session Identifier, PDU session ID, and / or wherein the QoS flow is identified by a QoS Flow Identifier, QFI; transmitting from the access and mobility management node to a session management node a request including an indication of the PDU sessions and / or QoS flows subject to SDT, particularly wherein the indication is based on the received information for SDT from the radio access network node or local policy, and particularly wherein the request is a Nsmf PDUSession UpdateSMContext Request; andtransmitting from the access and mobility management node to the radio access network node via the access and mobility management node, N3 tunnel information parameters associated with a selected user plane node received from the session management node.

26. The method of claim 25, wherein the indication from the radio access network node to the access and mobility management node is transmitted in a N2 MT Communication Handling request message.

27. The method of any one of claims from claim 25 to claim 26, wherein the method further comprises sending from the access and mobility management node to the radio access network node, a N2 MT Communication Handling response message, particularly wherein the response message indicates that the access and mobility management node acknowledges the request or that the access and mobility management node has taken the request into account.

28. The method of any one of claims from claim 25 to claim 27, wherein the access and mobility management node provides to the radio access network node the N3 tunnel information parameters received from the session management node in a N2 MT Communication Handling response message or triggers a separate PDU Session Resource Modify procedure to update the N3 tunnel information in the radio access network node.

29. The method of any one of claims from claim 25 to claim 28, wherein the access and mobility management node provides to the radio access network node an indication of support for MT-SDT for the PDU session, particularly based on an indication from the session management node.

30. The method of any one of claims from claim 25 to claim 29, wherein the access and mobility management node includes the DL data size information in the N2 DL Data Notification message to the radio access network node, if the DL data size information is provided by the session management node to the access and mobility management node.31 . The method of any one of claims from claim 25 to claim 30, wherein the method further comprises performing at the radio access network node, RAN paging towards the UE based on the parameters provided by the access and mobility management node and setting at the radio access network node the MT-SDT flag in the paging message if the DL data size is provided, wherein the MS-SDT flag is set if the DL data size crossed a threshold or a DL data size flag is provided from the session management node.

32. The method of any one of claims from claim 25 to claim 31 , wherein If the LIL NG-ll UP TNL Information IE is included in the MT COMMUNICATION HANDLING RESPONSE message, the radio access network node shall update the new user plane node endpoint of the NG-U transport bearer information, for delivery of UL PDUs to the session management node for the indicated QoS flows.

33. The method of any one of claims from claim 25 to claim 32, wherein the method further incudes: determining at an radio access network node, an eDRX cycle value for a User Equipment, UE, in RRCJNACTIVE state; initiating at the radio access network node, a Connection Inactive procedure with Core Network, CN, based Mobile Terminated, MT, communication handling; and transmitting from the radio access network node to the access and mobility management node, a N2 MT Communication Handling request message, wherein the request message indicates the UE's transition to RRCJNACTIVE state and provides the eDRX cycle value for the RRCJNACTIVE state.

34. The method of any one of claims from claim 25 to claim 33, wherein the radio access network node is a New Radio - Radio Access Network, NG-RAN, the access and mobility management node is an Access and Mobility Management Function, AMF, the session management node is a Session Management Function, SMF, the user plane node is a User Plane Function, UPF, particularly wherein the SMF is an Intermediate SMF, l-SMF, or a Visited SMF, V-SMF, and particularly wherein the UPF is an Intermediate UPF, l-UPF, or a Visited UPF, V-UPF.

35. A method performed by a session management node for Small Data Transmission, SDT, in a communications network, the method comprising: receiving at the session management node from an access and mobility management node a request including an indication of the Packet Data Unit, PDU, sessions and / or Quality of Service, QoS, flows subject to SDT, particularly wherein the indication is based on the received information for SDT from the radio access network node or local policy, and particularly wherein the request is a Nsmf PDUSession UpdateSMContext Request; inserting, selecting or reselecting at the session management node a user plane node that supports SDT, particularly if the current user plane node does not support SDT ; andtransmitting from the session management node to a radio access network node via the access and mobility management node, N3 tunnel information parameters associated with the selected user plane node.

36. The method of claim 35, further comprising: transmitting from the session management node to the user plane node rules for SDT data handling, particularly wherein the rules are for Mobile Terminated SDT, MT-SDT, and particularly wherein the rules are transmitted as part of the N4 Session establishment or update procedure.

37. The method of any one of claims from claim 35 to claim 36, further comprising: transmitting from the session management node to the user plane node an N4 Session establishment message indicating the user plane node to report DL data size.

38. The method of any one of claims from claim 35 to claim 37, further comprising: transmitting from the session management node to the user plane node an indication of support for MT-SDT for the PDll session.

39. The method of any one of claims from claim 35 to claim 38, wherein the method further comprises providing from the user plane node to the session management node, DL data size information when sending Data Notification, and wherein the session management node includes the DL data size information in the Namf MT EnableUEReachability message to the access and mobility management node, particularly wherein the DL data size information is a DL data size parameter or a DL data size flag indicating that the DL data size crossed a threshold configured in the session management node.

40. The method of any one of claims from claim 35 to claim 39, wherein the radio access network node is a New Radio - Radio Access Network, NG-RAN, the access and mobility management node is an Access and Mobility Management Function, AMF, the session management node is a Session Management Function, SMF, the user plane node is a User Plane Function, UPF, particularly wherein the SMF is an Intermediate SMF, l-SMF, or a Visited SMF, V-SMF, and particularly wherein the UPF is an Intermediate UPF, l-UPF, or a Visited UPF, V-UPF.41 . A method performed by a user plane node for Small Data Transmission, SDT, in a communications network, the method comprising:receiving at the user plane node from a session management node rules for SDT data handling, particularly wherein the rules are for Mobile Terminated SDT, MT-SDT, and particularly wherein the rules are transmitted as part of the N4 Session establishment or update procedure.

42. The method of claim 41 , further comprising: receiving at the user plane node from the session management node an N4 Session establishment message indicating the user plane node to report DL data size.

43. The method of any one of claims from claim 41 to claim 42, further comprising: receiving at the user plane node from the session management node an indication of support for MT-SDT for the PDll session.

44. The method of any one of claims from claim 41 to claim 43, wherein the method further comprises receiving at the user plane node from the session management node, DL data size information when sending Data Notification, and wherein the session management node includes the DL data size information in the Namf MT EnableUEReachability message to the access and mobility management node, particularly wherein the DL data size information is a DL data size parameter or a DL data size flag indicating that the DL data size crossed a threshold configured in the session management node.

45. The method of any one of claims from claim 41 to claim 44, wherein the radio access network node is a New Radio - Radio Access Network, NG-RAN, the access and mobility management node is an Access and Mobility Management Function, AMF, the session management node is a Session Management Function, SMF, the user plane node is a User Plane Function, UPF, particularly wherein the SMF is an Intermediate SMF, l-SMF, or a Visited SMF, V-SMF, and particularly wherein the UPF is an Intermediate UPF, l-UPF, or a Visited UPF, V-UPF.

46. Apparatus for Small Data Transmission, SDT, in a communications network, the apparatus comprising a processor and a memory, the memory containing instructions executable by the processor such that the apparatus is operable to perform the method of any one of claims from claim 15 to claim 24.

47. Apparatus for Small Data Transmission, SDT, in a communications network, the apparatus comprising a processor and a memory, the memory containing instructions executable by the processor such that the apparatus is operable to perform the method of any one of claims from claim 25 to claim 34.

48. Apparatus for Small Data Transmission, SDT, in a communications network, the apparatus comprising a processor and a memory, the memory containing instructions executable by the processor such that the apparatus is operable to perform the method of any one of claims from claim 35 to claim 40.

49. Apparatus for Small Data Transmission, SDT, in a communications network, the apparatus comprising a processor and a memory, the memory containing instructions executable by the processor such that the apparatus is operable to perform the method of any one of claims from claim 41 to claim 45.

50. A system comprising an apparatus as claimed in claim 46, an apparatus as claimed in claim 47, an apparatus as claimed in claim 48, and an apparatus as claimed in claim 49.51 . A computer-implemented system comprising one or more processors and one or more computer storage media storing computer-usable instructions that, when used by the one or more processors, cause the one or more processors to perform a method according to any one of claims from claim 15 to claim 45.

52. A computer program comprising instructions which, when executed on at least one processor, cause the at least one processor to perform a method according to any of claims from claim 15 to claim 45.

53. A computer program product, embodied on a non-transitory machine-readable medium, comprising instructions which are executable by a processor, causing the processor to perform the method according to any of claims from claim 15 to claim 45.

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