Method for session renewal after session management failure and reselection - Patents.com

Abstract

A wireless communication method is disclosed for use by a first session management function (SMF), the method including taking over control of a protocol data unit (PDU) session serviced by a second SMF and sending SMF change information associated with the PDU session to at least one network function associated with the PDU session.

Description

[Technical field]

[0001] This document describes wireless communications in general, and fifth generation (5G) in particular. th generation) communication. [Background technology]

[0002] In a 5G system, a user equipment (UE) can request a protocol data unit (PDU) session establishment to a network to obtain internet protocol (IP) connectivity services. In this case, a session management function (SMF) is selected to control the established PDU session, and such an SMF is called an anchor SMF. In addition, a user plane function (UPF) selected by the anchor SMF to assign a UE IP address is called a PDU Session Anchor (PSA) or PSA UPF.

[0003] Generally speaking, the anchor SMF and PSA UPF have their own serving areas and cannot serve the entire network (e.g., public land mobile network (PLMN)). In order to support PDU session services when the UE is outside the service area supported by the anchor SMF and PSA UPF, an intermediate SMF and intermediate UPF are inserted to serve the UE location area (i.e., the area where the UE is located). For example, the intermediate SMF can be a visited SMF (V-SMF) in a home-routed roaming scenario or an I-SMF in a non-roaming scenario. Therefore, the intermediate UPF can be a visited UPF (V-UPF) in a home-routed roaming scenario or an I-UPF in a non-roaming scenario.

[0004] A PDU session may involve an intermediate SMF or may involve no intermediate SMF. In a PDU session without an intermediate SMF, the anchor SMF maintains the UE's session management (SM) context and the PDU session context. In a PDU session with an intermediate SMF, the SM context is maintained by the intermediate SMF and the PDU session context is maintained by the anchor SMF. The intermediate SMF assigns an SM context ID that is used to locate the SM context in the intermediate SMF. The SM context includes the necessary information related to the AMF and the N3 tunnel, such as access and mobility management function (AMF) information, N3 tunneling information, etc. The PDU session context includes, for example, the UE IP address, PDU session policy information, N6 tunnel information, etc.

[0005] The anchor SMF is one of the most important network functions (NFs) that provide services to PDU sessions in 5G systems. If the anchor SMF fails or operates abnormally, the UE may lose the IP connectivity service completely. To avoid interruption of the IP connectivity service, an alternative anchor SMF can be selected to take over the PDU session when the original anchor SMF fails.

[0006] In the 5G system, the general concept of an NF set is introduced to support NF failure and restoration with less impact on service continuity. The concept of an NF set is designed in the 5G system to support stateless deployment of NFs and is commonly used in the case of NF failure and restoration. Specifically, NFs in the same NF set share resources (e.g., UE IP address resources) and session contexts (e.g., UE PDU session contexts). When the failure of one NF is detected by another NF, the detecting NF can select one NF in the same NF set of the failing NF to continue the service procedure.

[0007] Furthermore, a Packet Forwarding Control Protocol (PFCP) association may be set up between the SMF and the UPF before establishing the first PFCP session on that UPF. During the PFCP association setup procedure, the SMF may send SMF set information to the UPF. The UPF may use the SMF set information to transfer one PFCP session from the failed SMF to another SMF in the same SMF set.

[0008] The UPF performs periodic keep-alive detection (e.g., using a heartbeat procedure) with the SMFs to which the UPF is connected. When the UPF detects that one SMF has failed (e.g., the SMF is not responsive), the UPF reselects another SMF in the SMF set to take over the control of the affected PFCP session. According to existing procedures, the AMF may also reselect a new SMF in the SMF set when the AMF detects that the old SMF has failed (e.g., the old SMF is not responsive) and send PDU session-related messages to the SMF reselected by the AMF. However, the SMF reselected by the AMF may be different from the SMF reselected by the UPF. Under such conditions, the SMF reselected by the AMF needs to redirect the PDU session-related messages received from the AMF to the SMF reselected by the UPF, which may result in additional signaling exchanges and procedural complexities. In addition, potential signaling timeout errors may occur.

[0009] Therefore, the present disclosure provides a method that enables, when the UPF reselects another SMF to service a PDU session, the reselected SMF to proactively update the SMF information of the PDU session to other NFs, e.g., the AMF and PCF (Policy Control Function).

[0010] This document relates to a method that enables a reselected SMF to proactively update the SMF information of a PDU session to other Network Functions (NFs), in particular when a UPF reselects an SMF to take over control of a PDU session from another SMF, and relates to a method that enables a reselected SMF to proactively update the SMF information of a PDU session to other NFs. Summary of the Invention [Means for solving the problem]

[0011] The present disclosure relates to a wireless communication method for use in a first session management function (SMF), the method comprising: Taking over control of a protocol data unit (PDU) session served by the second SMF; and and transmitting SMF change information associated with the PDU session to at least one network function associated with the PDU session.

[0012] Various embodiments may preferably implement the following features. Preferably, the SMF modification information includes an identifier of the first SMF.

[0013] Preferably, the SMF change information is: An identifier for the second SMF, an identifier of a first SMF set that contains the first SMF; An identifier for the second SMF set that contains the second SMF, or A forwarding instruction indicating at least one PDU session to which the SMF change information applies.

[0014] Preferably, the transfer instruction indicates a single PDU session or multiple PDU sessions serviced by the second SMF.

[0015] Preferably, taking over control of a PDU session served by the second SMF comprises: The method includes receiving a request from a user plane function from a second SMF to take over control of a packet forwarding control protocol session corresponding to the PDU session.

[0016] Preferably, the at least one network function includes at least one of an access and mobility management function, a policy control function, an integrated data management, an intermediate SMF, or a visited SMF.

[0017] Preferably, the at least one network function includes a policy control function, and the SMF change information sent to the policy control function further includes a notification uniform resource identifier of a recipient of the session management policy update notification.

[0018] The present disclosure relates to a wireless communication method for use in an intermediate session management function (SMF), the method comprising: receiving, from a first SMF, SMF modification information associated with a protocol data unit (PDU) session serviced by a second SMF; and sending the SMF change information to an access and mobility management function associated with the PDU session.

[0019] Various embodiments may preferably implement the following features. Preferably, the SMF modification information includes an identifier of the first SMF.

[0020] Preferably, the SMF change information is: Identifier of the second SMF, an identifier of a first SMF set that contains the first SMF; An identifier for the second SMF set that contains the second SMF, or A forwarding instruction indicating at least one PDU session to which the SMF change information applies.

[0021] Preferably, the transfer instruction indicates a single PDU session or multiple PDU sessions serviced by the second SMF.

[0022] The present disclosure relates to a wireless communication method for network functionality, the method comprising: receiving, from a first session management function (SMF), SMF modification information associated with a protocol data unit (PDU) session serviced by a second SMF; and updating SMF information of at least one PDU session based on the SMF change information.

[0023] Various embodiments may preferably implement the following features. Preferably, the SMF modification information includes an identifier of the first SMF.

[0024] Preferably, the SMF change information is: An identifier for the second SMF, an identifier of a first SMF set that contains the first SMF; An identifier for the second SMF set that contains the second SMF, or A forwarding instruction indicating at least one PDU session to which the SMF change information applies.

[0025] Preferably, the transfer instruction indicates a single PDU session or multiple PDU sessions serviced by the second SMF.

[0026] Preferably, the SMF change information includes a forwarding instruction indicating a single PDU session or does not include a forwarding instruction, and updating the SMF information of at least one PDU session based on the SMF change information includes: This includes updating the SMF information of the PDU session based on the SMF change information.

[0027] Preferably, the SMF modification information includes a forwarding instruction indicating a plurality of PDU sessions serviced by the second SMF, and updating the SMF information of at least one PDU session based on the SMF modification information includes: and updating SMF information of multiple PDU sessions serviced by the second SMF based on the SMF change information.

[0028] Preferably, the network functions include at least one of an access and mobility management function, a policy control function, or integrated data management.

[0029] Preferably, the network functions include access and mobility management functions, and the SMF change information is received via an intermediate SMF.

[0030] Preferably, the network function includes a policy control function, and the SMF change information further includes a notification uniform resource identifier of a recipient of the session management policy update notification.

[0031] The present disclosure relates to a wireless device having a first session management function (SMF), a processor configured to take over control of a protocol data unit (PDU) session served by a second SMF; and a communication unit configured to transmit SMF change information associated with the PDU session to at least one network function associated with the PDU session.

[0032] Various embodiments may preferably implement the following features. Preferably, the processor is further configured to perform any of the wireless communication methods described above.

[0033] The present disclosure relates to a wireless device having an intermediate session management function (SMF). receiving, from the first SMF, SMF change information associated with a protocol data unit (PDU) session serviced by the second SMF; configured to send SMF change information to an access and mobility management function associated with the PDU session; Equipped with a communication unit.

[0034] Various embodiments may preferably implement the following features. Preferably, the wireless device further comprises a processor configured to perform any of the aforementioned wireless communication methods.

[0035] The present disclosure relates to a wireless device having network capabilities, a communication unit configured to receive, from a first session management function (SMF), SMF change information associated with a protocol data unit (PDU) session serviced by a second SMF; A processor configured to update SMF information of at least one PDU session based on the SMF change information.

[0036] Various embodiments may preferably implement the following features. Preferably, the processor is further configured to perform any of the wireless communication methods described above.

[0037] The present disclosure relates to a computer program product comprising computer readable program medium code stored thereon, which when executed by a processor causes the processor to perform a wireless communication method as set forth in any one of the preceding methods.

[0038] Exemplary embodiments disclosed herein are directed to providing features that will be readily apparent by reference to the following description in conjunction with the accompanying drawings. According to various embodiments, exemplary systems, methods, devices, and computer program products are disclosed herein. However, it is understood that these embodiments are presented by way of example and not by way of limitation, and it will be apparent to those skilled in the art upon reading this disclosure that various modifications to the disclosed embodiments may be made while remaining within the scope of this disclosure.

[0039] Therefore, the present disclosure is not limited to the exemplary embodiments and applications described and illustrated herein. Moreover, the specific order and / or hierarchy of things in the methods disclosed herein are merely exemplary approaches. Based on design preferences, the specific order or hierarchy of things in a disclosed method or process can be rearranged while remaining within the scope of the present disclosure. Thus, one skilled in the art will understand that the methods and techniques disclosed herein present various things or operations in a sample order, and that the present disclosure is not limited to the specific order or hierarchy presented, unless otherwise specified.

[0040] These and other aspects and implementations thereof are explained in more detail in the drawings, description, and claims. [Brief description of the drawings]

[0041] [Figure 1] FIG. 1 illustrates a schematic diagram of a 5G home routed roaming architecture according to one embodiment of the present disclosure. [Diagram 2] 1 illustrates a schematic diagram of a 5G non-roaming architecture according to one embodiment of the present disclosure. [Diagram 3] A schematic diagram of a PDU session establishment procedure according to one embodiment of the present disclosure is shown. [Figure 4] 1 illustrates a schematic diagram of a PFCP association setup procedure according to an embodiment of the present disclosure. [Diagram 5] FIG. 1 shows a schematic diagram of a procedure according to one embodiment of the present disclosure. [Figure 6] FIG. 1 shows a schematic diagram of a procedure according to one embodiment of the present disclosure. [Figure 7] FIG. 1 shows a schematic diagram of a procedure according to one embodiment of the present disclosure. [Figure 8] 1 illustrates an example schematic diagram of a wireless terminal according to one embodiment of the present disclosure. [Figure 9] FIG. 2 illustrates an example schematic diagram of a radio network node according to one embodiment of the present disclosure. [Figure 10] 1 shows a flowchart of a method according to one embodiment of the present disclosure. [Figure 11] 1 shows a flowchart of a method according to one embodiment of the present disclosure. [Figure 12] 1 shows a flowchart of a method according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0042] In this disclosure, the term "information" has the same meaning as or the same as "info."

[0043] FIG. 1 illustrates a 5G home-routed roaming architecture according to an embodiment of the present disclosure. In FIG. 1, the anchor SMF and the PSA UPF cannot directly serve the visited PLMN (VPLMN) where the UE is camped. FIG. 2 illustrates a 5G non-roaming architecture according to an embodiment of the present disclosure. In FIG. 2, the anchor SMF and the PSA UPF cannot directly serve the area where the UE is located (i.e., the UE location area). In FIG. 1 and FIG. 2, there are the following network functions and network entities:

[0044] 1) UE (User Equipment) 2) RAN (Radio Access Network): In a 5G network, the RAN may be a new radio (NR) base station.

[0045] 3) AMF (Access and Mobility Management Function): The AMF includes the functions of registration management, connection management, reachability management, and mobility management. The AMF also performs access authentication and authorization. The AMF is a non-access stratum (NAS) security termination, and relays the SM NAS between the UE and the SMF.

[0046] 4) SMF (Session Management Function) The SMF includes functions such as session establishment, modification and release, UE IP address allocation and management (including optional authorization functions), UP function selection and control, downlink data notification, etc. The SMF controls the UPF via the N4 association.

[0047] 5) UPF (User plane function) The UPF includes functions as an anchor point for intra- / inter-radio access technology (RAT) mobility, packet routing and forwarding, traffic usage reporting, user plane QoS processing, buffering of downlink packets and triggering of downlink data notification, etc. The UPF can be deployed as an intermediate UPF (I-UPF) or PSA. The PSA / UPF is a UPF that terminates the N6 interface towards the data network. The I-UPF provides traffic forwarding between the RAN and the PSA / UPF. The I-UPF can support "ULCL" (Uplink classifier: offloads uplink traffic based on target IP address) or "BP" (Branching point: offloads uplink traffic based on source IP address) to offload some traffic to a local PSA / UPF.

[0048] 6) PCF (Policy Control Function) The PCF provides QoS policy rules to the control plane functions to enforce the rules. The PCF translates Application Function (AF) requests into policies that apply to PDU sessions. The PCF provides AF-influenced traffic steering enforcement control on PCC rules to the SMF so that the SMF can establish data paths to offload traffic to the local data network.

[0049] 7) AF (Application Function) The AF interacts with the 3GPP core network to provide services, e.g., to support application influence on traffic routing. Based on the operator's deployment, AFs that are considered trusted by the operator may interact directly with the relevant network functions. AFs that are not authorized by the operator to directly access network functions shall use an external exposure framework via a network exposure function (NEF) to interact with the relevant network functions.

[0050] In the PDU session establishment procedure, if the selected anchor SMF and PSA UPF cannot serve the area where the UE is camped, the I-SMF and I-UPF need to be inserted (see FIG. 2). The visited SMF (V-SMF) shown in FIG. 1 (i.e., home-routed roaming scenario) plays a similar role to the I-SMF shown in FIG. 2 (i.e., non-roaming scenario). Therefore, in the present disclosure, the I-SMF may be equal to the V-SMF. Similarly, the I-UPF may be equal to the visited UPF (V-UPF) shown in FIG. 1 of the present disclosure.

[0051] 3 shows a schematic diagram of a PDU session establishment procedure according to an embodiment of the present disclosure. The PDU session establishment procedure in FIG. 3 includes an I-SMF insertion. Specifically, after the UE is registered in the 5G network, the UE can request a PDU session establishment procedure including the following steps:

[0052] Step 301: The UE sends a PDU session establishment request to the AMF. The PDU session establishment request is included in a non-access stratum (NAS) message and encapsulated in an N1 SM container. The NAS message may include Single Network Slice Selection Assistance information (S-NSSAI), the UE requested data network name (DNN), a PDU session ID, a request type, and an N1 SM container (containing the PDU session establishment request). The NAS message sent by the UE is encapsulated by the RAN in an N2 message towards the AMF.

[0053] Step 302: The AMF selects an appropriate SMF (i.e., anchor SMF) to serve the PDU session based on the requested DNN, S-NSSAI, and current UE location information. If the anchor SMF cannot serve the UE's current location, the AMF also decides to select an I-SMF for the PDU session.

[0054] Step 303: The AMF sends a Nsmf_PDUSession_CreateSMContext request to the I-SMF, where the Nsmf_PDUSession_CreateSMContext request includes a Subscription Permanent Identifier (SUPI), a selected DNN, a UE requested DNN, an S-NSSAI, a PDU Session ID, an AMF ID, a request type, an N1 SM container (PDU Session Establishment Request), a user location information, an access type, a RAT type, a Permanent Equipment Identifier (PEI), a General Public Subscriber Identifier (GPSI), an AMF callback URI for receiving SM context status notification, etc. The SUPI uniquely identifies the UE subscription. The AMF ID carries a Globally Unique AMF ID (GUAMI) that uniquely identifies the AMF serving the UE. The AMF callback URI for receiving SM context notifications is used by an SMF (e.g., I-SMF, anchor SMF) to send notifications of SM context status to the AMF.

[0055] Step 304: The I-SMF sends a Nsmf_PDUSession_CreateSMContext response to the AMF, where the Nsmf_PDUSession_CreateSMContext response includes a cause and an SM context ID. The SM context ID identifies the SM context created in the I-SMF for the UE.

[0056] Step 305: The I-SMF selects an I-UPF for serving the PDU session based on the UE location.

[0057] Step 306: The I-SMF initiates an N4 session establishment procedure with the selected I-UPF.

[0058] Step 307: The I-SMF sends a Nsmf_PDUSession_Create request to the anchor SMF, where the Nsmf_PDUSession_Create request includes the DNN, the S-NSSAI, the PDU Session ID, the I-SMF Instance ID, the I-SMF SM Context ID, and intermediate-core-network (ICN) tunnel information. The ICN tunnel information carries an I-UPF downlink (DL) Fully Qualified Tunnel Endpoint Identifier (F-TEID) that is used to identify the I-UPF's GTP-U (GPRS tunneling protocol user plane) tunnel information to receive downlink traffic.

[0059] Step 308: The anchor SMF sends a Nudm_SDM_Get request to a unified data management (UDM) to obtain session management subscription data. The UDM returns the requested data in a response message.

[0060] Step 309: The anchor SMF selects a UPF to act as the PSA. Step 310: The anchor SMF initiates an N4 session establishment procedure with the selected UPF.

[0061] Step 311: The anchor SMF sends a Nsm_PDUSession_Create response to the I-SMF, where the Nsm_PDUSession_Create response includes a quality of service (QoS) rule, a QoS flow level, a QoS parameter, a QoS flow ID (QFI), a QoS profile, a session maximum bit rate (MBR), and H-UPF tunnel information. The H-UPF tunnel information carries the H-UPF GTP-U tunnel information of the PSA UPF for receiving UL traffic.

[0062] Step 312: The I-SMF initiates an N4 session modification procedure with the I-UPF to update the GTP-U tunnel information of the PSA UPF, i.e., the UPF UL F-TEID.

[0063] Step 313: The I-SMF sends a Namf_Communication_N1N2MessageTransfer request to the AMF, in which the Namf_Communication_N1N2MessageTransfer request includes a PDU session ID, N2 SM information (PDU session ID, QFI, QoS profile, N3 CN tunnel information), and an N1 SM container (PDU session establishment acceptance).

[0064] The N2 SM information carries information that the AMF forwards to the RAN, including N3 CN tunnel information carrying the I-UPF UL F-TEID, the QFI and QoS profile used by the RAN to set up the QoS flow. In one embodiment, the N1 SM container includes a PDU session establishment acceptance that the AMF provides to the UE.

[0065] Step 314: The AMF sends an N2 PDU session request to the RAN, where the N2 PDU session request includes N2 SM information, NAS message (PDU Session ID, N1 SM container (PDU Session Establishment Accept)). The AMF sends a NAS message to the RAN, including a PDU Session ID and a PDU Session Establishment Accept targeted to the UE, and the N2 SM information received from the SMF in the N2 PDU Session Request.

[0066] Step 315: The RAN may issue an AN-specific signaling exchange with the UE related to the information received from the SMF. For example, in the case of a 3GPP RAN, an RRC connection reconfiguration may be performed with the UE that establishes the necessary RAN resources related to the QoS rules for the PDU session request. The RAN forwards a NAS message (PDU Session ID, N1 SM Container (PDU Session Establishment Accept)) to the UE. The RAN also assigns AN N3 tunnel information to the PDU session.

[0067] Step 316: The RAN sends a PDU session response to the AMF, where the N2 PDU session response includes a PDU session ID, a cause, and N2 SM information (PDU session ID, AN tunnel information, and a list of accepted / rejected QFIs).

[0068] The AN tunnel information corresponds to the access network address of the N3 tunnel corresponding to the PDU session.

[0069] Step 317: The AMF sends Nsmf_PDUSession_UpdateSMContext to the I-SMF, and the Nsmf_PDUSession_UpdateSMContext request includes N2 SM information.

[0070] The AMF forwards the N2 SM information received from the RAN to the I-SMF. If the N2 SM information contains a list of rejected QFIs, the SMF shall release the QoS profiles associated with the rejected QFIs.

[0071] Step 318: The I-SMF initiates an N4 session modification procedure with the I-UPF. The I-SMF provides the RAN tunnel information to the I-UPF and corresponding forwarding rules.

[0072] Step 319: The I-SMF sends a Nsmf_PDUSession_UpdateSMContext response to the AMF.

[0073] Figure 4 shows a schematic diagram of a PFCP association setup procedure according to one embodiment of the present disclosure. In Figure 4, the SMF selects a UPF and the PFCP association has not yet been established. During the PFCP association setup procedure, the SMF provides its SMF set information to the UPF. In one embodiment, the SMF initiates the PFCP association setup procedure to request that a PFCP association be set up towards the UPF before establishing the first PFCP session on this UPF. Specifically, the PFCP association setup procedure shown in Figure 4 includes the following steps:

[0074] Step 401: The SMF sends a PFCP association setup request to the UPF. In one embodiment, the PFCP association setup request includes: -SMF Node ID: The node ID may be set to a fully qualified domain name (FQDN) representing the SMF, and / or -SMF Set ID: The SMF Set ID is set to the FQDN that represents the SMF set.

[0075] Step 402: Upon receiving the PFCP association setup request, the UPF stores the node ID of the SMF, and stores the SMF set ID if received. If the PFCP association setup request is accepted, the UPF sends a PFCP association setup response to the SMF, including a successful cause.

[0076] Step 403: After the PFCP association is successfully established between the SMF and the UPF, the UPF checks the available status of the SMF using the heartbeat procedure.

[0077] Figure 5 shows a schematic diagram of a procedure according to one embodiment of the present disclosure. In Figure 5, the UPF detects a failure of an SMF and reselects another SMF to take over control of a PDU session from the failed SMF. In particular, the procedure shown in Figure 5 includes:

[0078] Step 501: During the PDU session establishment procedure, the SMF1 receives a PDU session establishment request message from the AMF (not shown in FIG. 5). The PDU session establishment request message triggers the SMF1 to establish a PFCP session with the UPF. The SMF1 selects an appropriate UPF based on the data network name (DNN) and other information.

[0079] Step 502: SMF1 sends a PFCP session establishment request to the selected UPF. In one embodiment, SMF1 assigns a Session Endpoint Identifier (SEID) that is used to uniquely identify the PFCP session. In the request message, SMF1 includes a Control Plane Fully Qualified SEID (CP F-SEID). Note that the CP F-SEID is unique within at least one SMF set and may be unique within one SMF.

[0080] Step 503: The UPF returns a PFCF session establishment response message to the SMF1. Step 504: SMF1 responds to the AMF by sending a PDU session establishment response message.

[0081] Step 505: The UPF continues to monitor the status of the SMF1 using the heartbeat message. In this embodiment, the UPF can later detect that the SMF1 has failed.

[0082] Step 506: If or after the UPF detects that SMF1 has failed (e.g., SMF1 is not responding), the UPF reselects another SMF in the SMF set, e.g., SMF2, based on the SMF set information received during the PFCP association setup procedure. The UPF initiates a PFCP session-related request (e.g., PFCP session report request) to the new SMF2.

[0083] When sending a request to the new SMF2, the UPF sets the SEID field in the PFCP header of the PFCP request to 0 and includes the CP F-SEID assigned by the previous SMF1 in the request. The SEID set to 0 gives an instruction / instruction to the SMF2 that the UPF is requesting the SMF2 to take over this PFCP session. The CP F-SEID assigned by the previous SMF1 allows the new SMF2 to fetch the UE's PFCP session context, which can be stored in external storage (e.g., UDSF).

[0084] Step 507: If or after receiving a request from the UPF with the SEID field set to 0 and the CP F-SEID assigned by the previous SMF1, the reselected SMF2 takes over control of the PFCP session from the previous SMF1.

[0085] Step 508: The SMF2 responds to the UPF by sending a response corresponding to the PFCP session-related message.

[0086] In Figure 5, the new SMF2 does not proactively update the new SMF information to the AMF, for example, after the new SMF2 takes over the PFCP session. To avoid potential problems and improve procedure efficiency, a method is provided in the present disclosure that enables a reselected SMF (e.g., SMF2) to proactively update the SMF information of the PDU session to other NFs (e.g., AMF and PCF).

[0087] Figure 6 shows a schematic diagram of a procedure according to one embodiment of the present disclosure, in which the reselected SMF (i.e., SMF2) informs the AMF that the reselected SMF will take over control of the PDU session (e.g., the SM context has been transferred to the reselected SMF after the UPF selects a new SMF to take over control of the PFCP session).

[0088] Step 601: The UPF detects that SMF1 has failed (e.g., SMF1 is unresponsive or behaving abnormally) and reselects a new SMF (i.e., SMF2) to service the PDU session.

[0089] In one embodiment, if SMF set information was received during the PFCP association setup procedure, the new SMF2 may be selected from the same SMF set. Alternatively or additionally, if alternative SMF information was received during the PFCP association setup / update procedure, the new SMF may be selected from an alternative SMF.

[0090] The UPF triggers a procedure towards the new SMF2 to request it to take over control of the PFCP session, for example as described in the procedure shown in Figure 5.

[0091] Step 602: The new (anchor) SMF2 sends an SM context status notification request message to the AMF to proactively update the AMF with the new anchor SMF information.

[0092] In one embodiment, the SM context status notification request message includes an ID of the PDU session.

[0093] In one embodiment, a new SMF ID (i.e., the SMF ID of SMF2 in this embodiment) is included in the SM context status notification request message to indicate that the PDU session will be taken over by the new anchor SMF2 (i.e., the SMF reselected by the UPF).

[0094] In one embodiment, the SM context status notification request message may further include at least one of the following:

[0095] - New SMF Set ID, indicating the SMF Set ID of the new SMF, - the old SMF ID indicating the previous SMF serving the PDU session, - Old SMF Set ID, indicating the SMF Set ID of the old SMF, - Forwarding indication. The forwarding indication indicates that the SMF information replacement (i.e., replacing the old SMF with the new SMF) applies to either (a) a single PDU session (related to the request and / or) serviced by the old SMF, or (b) a batch of PDU sessions serviced by the old SMF. In one embodiment, by default, the absence of this forwarding indication means that the SMF information replacement applies to the single PDU session related to the request.

[0096] In one embodiment, the old SMF ID is included in the SM context status notification request message together with the new SMF ID, regardless of whether the reselected SMF2 and the previous SMF1 are in the same SMF set. In addition, a forwarding indication may also be included in the SM context status notification request message to indicate the scope of the SMF information replacement, especially if the SMF replacement applies to a batch of PDU sessions (e.g., at least a portion of the PDU sessions served by SMF1).

[0097] In one embodiment, if the reselected SMF2 and previous SMF1 are not in the same SMF set, the new SMF set ID and / or the old SMF set ID and / or the old SMF set ID are included in the SM context status notification request message together with the new SMF ID. In this embodiment, a forwarding indication may also be included in the SM context status notification request message to indicate the scope of the SMF information replacement, especially if the SMF replacement applies to a batch of PDU sessions.

[0098] In step 602, the AMF responds to SMF2 by sending an SM context status notification response message to SMF2.

[0099] Step 603: When / after receiving an SM context status notification request message carrying SMF change information, the AMF performs SMF information replacement.

[0100] In one embodiment, if the SM context status notification request message does not include a forwarding instruction, the AMF updates the PDU session-related information and replaces the old SMF ID with the new SMF ID.

[0101] In one embodiment, if a forwarding indication is provided and set to indicate "single PDU session", the AMF updates the PDU session related information to replace the old SMF ID with the new SMF ID.

[0102] In one embodiment, if a forwarding indication is provided and set to "Batch of PDU sessions", the AMF updates the PDU session-related information for all affected PDU sessions (e.g., PDU sessions served by SMF1) to replace the old SMF ID with the new SMF ID.

[0103] Step 604: The new anchor SMF2 initiates the SM policy association establishment procedure or the SM policy association update procedure to the PCF by sending a Npcf_SMPolicyControl_Create request message or a Npcf_SMPolicyControl_Update request message.

[0104] In one embodiment, the Npcf_SMPolicyControl_Create or Npcf_SMPolicyControl_Update request message includes an ID of the PDU session.

[0105] Similar to step 602, the new SMF2 may include the new SMF ID in the request message to the PCF. In one embodiment, the request message further carries at least one of the following: new SMF Set ID, old SMF ID, old SMF Set ID, forwarding instruction. Alternatively or additionally, the new anchor SMF2 may also include a notification (uniform resource identifier) ​​URI in the request message, where the notification URI is used to identify the recipient of the SM policy update notification sent by the PCF.

[0106] In one embodiment, the PCF responds to the SMF2 by sending an Npcf_SMPolicyControl_Create response message or an Npcf_SMPolicyControl_Update response message to the SMF2.

[0107] In step 604, the PCF performs SMF information replacement in the same manner as the AMF does in step 603.

[0108] Step 605: The new anchor SMF2 initiates the SMF Registration procedure to the UDM by sending a Nudm_UECM_Registration request message.

[0109] In one embodiment, the Nudm_UECM_Registration request message includes an ID of the PDU session.

[0110] Similar to step 602, the new SMF2 includes the new SMF ID in the request message sent to the UDM. In one embodiment, the request message may further carry at least one of the following: new SMF Set ID, old SMF ID, old SMF Set ID, and forwarding indication.

[0111] In one embodiment, the UDM responds to the SMF2 by sending a Nudm_UECM_Registration response message to the SMF2. Additionally, the UDM performs SMF information replacement similar to the AMF in step 603.

[0112] Figure 7 shows a schematic diagram of a procedure according to one embodiment of the present disclosure. In Figure 7, an I-SMF / V-SMF is involved in a PDU session. The reselected anchor SMF (i.e., SMF2) informs the AMF via the I-SMF / V-SMF that the reselected anchor SMF takes over control of the PDU session (i.e., the PDU session context has been transferred to the reselected anchor SMF after the UPF selects a new anchor SMF to take over control of the PFCP session).

[0113] Step 701: The UPF detects that SMF1 has failed (e.g., SMF1 is not responding) and reselects a new SMF2 to service the PDU session.

[0114] If SMF set information was received during the PFCP association setup procedure, a new SMF2 is selected from the same SMF set. Alternatively or additionally, if alternative SMF information was received during the PFCP association setup / update procedure, a new SMF is selected from the alternative SMF.

[0115] In step 701, the UPF triggers a procedure to the new SMF (i.e., SMF2) to request the new SMF to take over the PFCP session, similar to the UPF in FIG. 5.

[0116] In this embodiment, the new anchor SMF2 performs either step 702a or step 702b to notify the I-SMF / V-SMF of the changes associated with the anchor SMF.

[0117] Step 702a: The new anchor SMF2 sends a Nsmf_PDUSession_Update request message to the I-SMF / V-SMF. The Nsmf_PDUSession_Update request message may include an ID of the PDU session. Similar to step 602, the new anchor SMF2 includes a new SMF ID in the request message sent to the I-SMF / V-SMF. The request message may further carry at least one of a new SMF set ID, an old SMF ID, an old SMF set ID, and a forwarding indication.

[0118] In step 702a, the I-SMF / V-SMF responds to SMF2 by sending a Nsmf_PDUSession_Update response message to SMF2.

[0119] Step 702b: The new anchor SMF2 sends a Nsmf_PDUSession_StatusNotify request message to the I-SMF / V-SMF. The Nsmf_PDUSession_StatusNotify request message may include an ID of the PDU session. Similar to step 602, the new anchor SMF2 includes the new SMF ID in the request message sent to the I-SMF / V-SMF. The request message may further carry at least one of the following: a new SMF set ID, an old SMF ID, an old SMF set ID, and a forwarding indication.

[0120] In step 702b, the I-SMF / V-SMF responds to SMF2 by sending a Nsmf_PDUSession_StatusNotify response message to SMF2.

[0121] In the embodiment shown in FIG. 7, the I-SMF / V-SMF performs either step 703a or step 703b to notify the AMF about the changes associated with the anchor SMF.

[0122] Step 703a: The I-SMF / V-SMF sends a Nsmf_PDUSession_SMContextStatusNotify request message to the AMF to proactively update the AMF with new anchor SMF information. The Nsmf_PDUSession_SMContextStatusNotify request message may include an ID of the PDU session. The I-SMF / V-SMF includes the new SMF ID and, optionally, at least one of the new SMF Set ID, old SMF ID, old SMF Set ID, and forwarding indication in the request message sent to the AMF if such information is received from the new anchor SMF2.

[0123] Step 703b: The I-SMF / V-SMF sends a Namf_Communication_N1N2MessageTransfer request message to the AMF to proactively update the AMF with new anchor SMF information. The Namf_Communication_N1N2MessageTransfer request message may include an ID of the PDU session. The I-SMF / V-SMF includes the new SMF ID and, optionally, at least one of the new SMF set ID, old SMF ID, old SMF set ID, and transfer indication in the request message sent to the AMF if such information is received from the new anchor SMF2.

[0124] Step 704: The AMF performs SMF information replacement like the AMF in step 603. Step 705: The new anchor SMF2 initiates the SM policy association establishment procedure or the SM policy association update procedure by sending a Npcf_SMPolicyControl_Create request message or a Npcf_SMPolicyControl_Update request message to the PCF. The Npcf_SMPolicyControl_Create request message or the Npcf_SMPolicyControl_Update request message may include an ID of the PDU session. Like the SMF2 in step 604, the new anchor SMF2 includes the new SMF ID in the request message to the PCF, which optionally further carries at least one of the new SMF set ID, the old SMF ID, the old SMF set ID, and a forwarding indication. The new anchor SMF2 may also include a notification URI in the message, which is used to identify the recipient of the SM policy update notification sent by the PCF.

[0125] In step 705, the PCF responds to the SMF2 by sending a Npcf_SMPolicyControl_Create response message or a Npcf_SMPolicyControl_Update response message to the SMF2. Furthermore, the PCF performs SMF information replacement similar to the AMF in step 603.

[0126] Step 706: The new anchor SMF2 initiates the SMF Registration procedure by sending a Nudm_UECM_Registration request message to the UDM. The Nudm_UECM_Registration request message may include an ID of the PDU session. Similar to step 605, the new anchor SMF2 includes the new SMF ID in the request message to the UDM, and the request message may further carry at least one of the new SMF set ID, the old SMF ID, the old SMF set ID, and a forwarding indication.

[0127] In step 706, the UDM responds to the SMF2 by sending a Nudm_UECM_Registration response message to the SMF2. The UDM performs SMF information substitution as with the AMF in step 603.

[0128] In one embodiment of the present disclosure, a new anchor SMF (e.g., SMF2 in FIGS. 5-7) receives a PFCP session-related message from the UPF to take over control of the PFCP session from an old SMF (e.g., SMF1 in FIGS. 5-7). For example, the PFCP session-related message indicates the new anchor SMF taking over control of the PFCP session. Alternatively or additionally, the PFCP session-related message indicates that the old SMF serving the PFCP session has failed / behaved abnormally. Under such conditions, the new anchor SMF sends SMF change information to connected network functions related to the PDU session, such as AMF, intermediate SMF, PCF, and / or UDM.

[0129] In one embodiment, the SMF change information includes a new SMF ID that is used to indicate that the PDU session will be taken over by a new anchor SMF (i.e., the SMF reselected by the UPF).

[0130] In one embodiment, the SMF change information may further include at least one of an old SMF ID, a new SMF set ID, an old SMF set ID, and a forwarding instruction.

[0131] In one embodiment, the forwarding instruction indicates that the SMF information replacement (i.e., replacing an old SMF with a new SMF) applies to either a single PDU session served by the old SMF or a batch of PDU sessions served by the old SMF.

[0132] In one embodiment of the present disclosure, the intermediate SMF may receive SMF modification information (associated with a PDU session) from the new anchor SMF and send the SMF modification information to the corresponding AMF.

[0133] In one embodiment, the SMF change information includes a new SMF ID that is used to indicate that the PDU session will be taken over by a new anchor SMF (i.e., the SMF reselected by the UPF).

[0134] In one embodiment, the SMF change information may further include at least one of an old SMF ID, a new SMF set ID, an old SMF set ID, and a forwarding instruction.

[0135] In one embodiment, the forwarding instruction indicates that the SMF information replacement (i.e., replacing an old SMF with a new SMF) applies to either a single PDU session served by the old SMF or a batch of PDU sessions served by the old SMF.

[0136] In one embodiment of the present disclosure, the AMF / PCF / UDM receives SMF change information (associated with the PDU session). It should be noted that if no intermediate SMF is involved, the AMF can receive the SMF change information directly from the new anchor SMF. Alternatively, the AMF can receive the SMF change information from the intermediate SMF if an intermediate SMF is involved. Furthermore, the PCF / UDM receives the SMF change information from the new anchor SMF. Based on the SMF change information, the AMF / PCF / UDM updates the SMF information of the affected PDU session.

[0137] In one embodiment, the SMF change information includes a new SMF ID that is used to indicate that the PDU session will be taken over by a new anchor SMF (i.e., the SMF reselected by the UPF).

[0138] In one embodiment, the SMF change information may further include at least one of an old SMF ID, a new SMF set ID, an old SMF set ID, and a forwarding instruction.

[0139] In one embodiment, the forwarding instruction indicates that the SMF information replacement (i.e., replacing an old SMF with a new SMF) applies to either a single PDU session served by the old SMF or a batch of PDU sessions served by the old SMF.

[0140] In one embodiment of SMF change information without a forwarding instruction, the AMF / PCF / UDM updates the PDU session-related information of the PDU session corresponding to the SMF change information to replace the old SMF ID with the new SMF ID.

[0141] In one embodiment of SMF change information in which the transfer instruction is set / indicated to “single PDU session”, the AMF / PCF / UDM updates the PDU session-related information corresponding to the SMF change information to replace the old SMF ID with the new SMF ID.

[0142] In one embodiment of SMF change information where the forwarding instruction is set / indicated to "Batch of PDU sessions", the AMF / PCF / UDM updates the PDU session related information for all affected PDU sessions to replace the old SMF ID with the new SMF ID.

[0143] In one embodiment, the SMF change information received by the PCF may further include a notification URI that identifies the recipient of the SM policy update notification sent by the PCF.

[0144] FIG. 8 relates to a schematic diagram of a wireless terminal 80 according to an embodiment of the present disclosure. The wireless terminal 80 may be a user equipment (UE), a mobile phone, a laptop, a tablet computer, an e-book, or a portable computer system, and is not limited herein. The wireless terminal 80 may include a processor 800, such as a microprocessor or an application specific integrated circuit (ASIC), a storage unit 810, and a communication unit 820. The storage unit 810 may be any data storage device that stores program code 812 that is accessed and executed by the processor 800. Embodiments of the storage unit 812 include, but are not limited to, a subscriber identity module (SIM), a read-only memory (ROM), a flash memory, a random-access memory (RAM), a hard disk, and an optical data storage device. The communication unit 820 may be a transceiver, and is used to transmit and receive signals (e.g., messages or packets) according to the processing results of the processor 800. In one embodiment, the communication unit 820 transmits and receives signals via at least one antenna 822 as shown in FIG.

[0145] In one embodiment, the memory unit 810 and the program code 812 may be omitted and the processor 800 may include a memory unit having the program code stored therein.

[0146] The processor 800 may, for example, by executing program code 812 to perform any of the steps in the illustrated embodiments at the wireless terminal 80 .

[0147] The communication unit 820 may be a transceiver. Alternatively or additionally, the communication unit 820 may combine a transmitting unit and a receiving unit configured to transmit and receive signals, respectively, to and from a wireless network node (e.g., a base station).

[0148] 9 relates to a schematic diagram of a radio network node 90 according to one embodiment of the present disclosure. The radio network node 90 may be a satellite, a base station (BS), a network entity, a Mobility Management Entity (MME), a Serving Gateway (S-GW), a Packet Data Network (PDN) Gateway (P-GW), a radio access network (RAN), a next generation RAN (NG-RAN) node, a gNB, an eNB, a gNB central unit (gNB-CU), a gNB distributed unit (gNB-DU), a data network, a core network, or a Radio Network Controller (RNC), and is not limited herein. Furthermore, the radio network node 90 may comprise (perform) at least one network function, such as an access and mobility management function (AMF), a session management function (SMF), a user place function (UPF), a policy control function (PCF), an application function (AF), a unified data management (UDM), etc. The radio network node 90 may include a processor 900, such as a microprocessor or an ASIC, a storage unit 910, and a communication unit 920. The storage unit 910 may be any data storage device that stores program code 912 that is accessed and executed by the processor 900. Examples of the storage unit 912 include, but are not limited to, a SIM, a ROM, a flash memory, a RAM, a hard disk, and an optical data storage device.The communication unit 920 may be a transceiver and is used to transmit and receive signals (e.g., messages or packets) according to the processing results of the processor 900. In one example, the communication unit 920 transmits and receives signals via at least one antenna 922 shown in FIG.

[0149] In one embodiment, the storage unit 910 and the program code 912 may be omitted. The processor 900 may include a storage unit having program code stored therein.

[0150] The processor 900 may perform any of the steps described in the illustrated embodiment at the radio network node 90, for example by executing the program code 912.

[0151] The communication unit 920 may be a transceiver. Alternatively or additionally, the communication unit 920 may combine a transmitting unit and a receiving unit configured to transmit and receive, respectively, signals to and from a wireless terminal (e.g., user equipment or another wireless network node).

[0152] 10 shows a flowchart of a method according to one embodiment of the present disclosure. The method shown in FIG. 10 may be used in a first SMF (e.g., a wireless device that includes an SMF or a wireless device that performs at least a part of the functionality of an SMF) and includes the following steps:

[0153] Step 1001: Take over control of a PDU session served by a second SMF.

[0154] Step 1002: Send SMF change information associated with the PDU session to at least one NF associated with the PDU session.

[0155] In the method shown in Figure 10, a first SMF takes over control of a PDU session initially served by a second SMF. For example, a failure of the second SMF may be detected by the UPF, and the first SMF may receive a request (e.g., a PFCP session-related request) from the second SMF instructing the first SMF to take over control of the PDU session (e.g., a corresponding PFCP session). Under such conditions, the first SMF sends SMF change information associated with the PDU session to at least one NF associated with the PDU session to proactively update the SMF information of the PDU session.

[0156] In one embodiment, the SMF change information may include or be associated with an ID of the PDU session to identify the PDU session.

[0157] In one embodiment, the SMF modification information includes an ID of the first SMF. In one embodiment, the SMF change information is: ID of the second SMF, ID of the first SMF set that contains the first SMF, The ID of the second SMF set that contains the second SMF, or A forwarding instruction indicating at least one PDU session to which the SMF change information applies.

[0158] In one embodiment, the forwarding indication indicates a single PDU session or multiple PDU sessions serviced by the second SMF.

[0159] In one embodiment of SMF modification information without a forwarding instruction, the SMF modification information is applied in a default manner (e.g., to only PDU sessions or to all PDU sessions serviced by the second SMF).

[0160] In one embodiment, at least one NF includes an AMF and / or a PCF and / or a UDM and / or an I-SMF / V-SMF.

[0161] In an embodiment in which the SMF change information is sent to the PCF, the first SMF may further include a notification URI of the recipient of the SM policy update notification in the SMF change information.

[0162] 11 shows a schematic diagram of a method according to one embodiment of the present disclosure. The method shown in FIG. 11 may be used in an intermediate SMF (e.g., an I-SMF / V-SMF, a wireless device comprising an I-SMF / V-SMF, or a wireless device performing at least a part of the functionality of an I-SMF / V-SMF), and includes the following steps:

[0163] Step 1101: Receive SMF change information associated with a PDU session serviced by a second SMF from a first SMF.

[0164] Step 1102: Send SMF change information to the AMF associated with the PDU session. In the method of Figure 11, the intermediate SMF receives SMF modification information associated with a PDU session serviced by a second SMF from a first SMF, in which case the intermediate SMF transmits / forwards the received SMF modification information to an AMF associated with the PDU session.

[0165] In one embodiment, the SMF change information may include or be associated with an ID of the PDU session to identify the PDU session.

[0166] In one embodiment, the SMF modification information includes an ID of the first SMF. In one embodiment, the SMF change information is: ID of the second SMF, ID of the first SMF set that contains the first SMF, The ID of the second SMF set that contains the second SMF, or A forwarding instruction indicating at least one PDU session to which the SMF change information applies.

[0167] In one embodiment, the forwarding indication indicates a single PDU session or multiple PDU sessions serviced by the second SMF.

[0168] In one embodiment of SMF modification information without a forwarding instruction, the SMF modification information is applied in a default manner (e.g., to only PDU sessions or to all PDU sessions serviced by the second SMF).

[0169] 12 shows a flowchart of a method according to an embodiment of the present disclosure. The method shown in FIG. 12 may be used in an NF (e.g., an AMF / PCF / UDM, a wireless device having an AMF / PCF / UDM, or a wireless device performing at least a part of the functions of an AMF / PCF / UDM), and includes the following steps:

[0170] Step 1201: Receive SMF change information associated with a PDU session serviced by a second SMF from a first SMF.

[0171] Step 1202: Update the SMF information of at least one PDU session based on the SMF change information.

[0172] In the method shown in Figure 12, an NF receives SMF change information associated with a PDU session served by a second SMF from a first SMF. Based on the SMF change information, the NF updates SMF information of at least one PDU session (e.g., only the PDU session associated with the SMF change information or all PDU sessions served by the second SMF).

[0173] In one embodiment, the SMF change information may include or be associated with an ID of the PDU session to identify the PDU session.

[0174] In one embodiment, the SMF modification information includes an ID of the first SMF. In one embodiment, the SMF change information is: ID of the second SMF, ID of the first SMF set that contains the first SMF, The ID of the second SMF set that contains the second SMF, or A forwarding instruction indicating at least one PDU session to which the SMF change information applies.

[0175] In one embodiment, the forwarding indication indicates a single PDU session or multiple PDU sessions serviced by the second SMF.

[0176] In one embodiment of the SMF modification information without a forwarding instruction, the SMF modification information is applied in a default manner, for example, the NF can update the SMF information of only the PDU session or all PDU sessions serviced by the second SMF according to the SMF modification information.

[0177] In one embodiment where the NF is an AMF, the SMF modification information may be received from an intermediate SMF. In an embodiment where the NF is a PCF, the SMF change information may further include a notification URI for the recipient of the SM policy update notification.

[0178] Although various embodiments of the present disclosure have been described above, it should be understood that they are presented only as examples and not as limitations. Similarly, various figures may depict example architectures or configurations provided to enable those skilled in the art to appreciate the exemplary features and functionality of the present disclosure. However, such skilled in the art will appreciate that the present disclosure is not limited to the illustrated example architectures or configurations, but may be implemented using various alternative architectures and configurations. Furthermore, as will be appreciated by those skilled in the art, one or more features of one embodiment may be combined with one or more features of another embodiment described herein. Thus, the breadth and scope of the present disclosure should not be limited by any of the exemplary embodiments described above.

[0179] It is also understood that any reference to an element herein using a designation such as "first," "second," etc., does not generally limit the quantity or order of those elements. Rather, these designations may be used herein as a convenient means of distinguishing between two or more elements or instances of an element. Thus, a reference to a first and second element does not imply that only two elements may be used or that the first element must precede the second element in any way.

[0180] Further, those skilled in the art will understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, the data, instructions, commands, information, signals, bits, and symbols that may be referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0181] Those skilled in the art will further appreciate that any of the various illustrative logical blocks, units, processors, means, circuits, methods, and functions described in connection with the embodiments disclosed herein may be realized by electronic hardware (e.g., digital implementations, analog implementations, or a combination of the two), firmware, various forms of programs or design code incorporating instructions (which may be referred to herein for convenience as "software" or "software units"), or any combination of these technologies.

[0182] To clearly illustrate this interchangeability with hardware, firmware, and software, various exemplary components, blocks, units, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware, firmware, or software, or a combination of these technologies, depends on the particular application and design constraints imposed on the overall system. Those skilled in the art may implement the described functionality in various ways for each particular application, but such implementation decisions should not be interpreted as departing from the scope of the present disclosure. According to various embodiments, a processor, device, component, circuit, structure, machine, unit, etc. may be configured to perform one or more of the functions described herein. The term "configured for" or "configured to" as used herein with respect to a specified operation or function refers to a processor, device, component, circuit, structure, machine, unit, etc. that is physically constructed, programmed, and / or arranged to perform the specified operation or function.

[0183] Furthermore, those skilled in the art will appreciate that the various exemplary logical blocks, units, devices, components and circuits described herein can be implemented in or performed by an integrated circuit (IC), which may include a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, or any combination thereof. The logical blocks, units and circuits may further include an antenna and / or a transceiver for communicating with various components in a network or device. The general purpose processor may be a microprocessor, but in alternative examples, the processor may be any conventional processor, controller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other suitable configuration for performing the functions described herein. If implemented in software, the functions may be stored as one or more instructions or code on a computer-readable medium. Thus, the steps of a method or algorithm disclosed herein can be implemented as software stored on a computer-readable medium.

[0184] Computer-readable media includes both computer storage media and communication media, including any medium that can enable a computer program or code to be transferred from one place to another. Storage media can be any available medium that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer.

[0185] The term "unit" as used herein refers to software, firmware, hardware, and any combination of these elements for performing the relevant functions described herein. Furthermore, for purposes of explanation, various units are described as separate units, but as will be apparent to one skilled in the art, two or more units may be combined to form a single unit that performs the relevant functions according to embodiments of the present disclosure.

[0186] Furthermore, memory or other storage devices, as well as communication components, may be used in embodiments of the present disclosure. For clarity, it will be appreciated that the above description has described embodiments of the present disclosure with reference to different functional units and processors. However, it will be apparent that any suitable distribution of functionality between different functional units, processing logic elements, or domains may be used without detracting from the present disclosure. For example, functions shown to be performed by separate processing logic elements or controllers may be performed by the same processing logic element or controller. Thus, references to specific functional units are merely to suitable means for providing the described functions, rather than to a strict logical or physical structure or organization.

[0187] Various modifications to the embodiments described in this disclosure will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments without departing from the scope of the claims. Thus, the present disclosure is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the novel features and principles disclosed herein as set forth in the following claims.

Claims

1. 1. A wireless communication method for use in a first session management function (SMF), comprising: Taking over control of a protocol data unit (PDU) session served by the second SMF; and A wireless communication method comprising: transmitting SMF change information associated with the PDU session to at least one network function associated with the PDU session.

2. The wireless communication method according to claim 1 , wherein the SMF modification information includes an identifier of the first SMF.

3. The SMF change information is an identifier of the second SMF; an identifier of a first SMF set that includes the first SMF; an identifier of a second SMF set that includes the second SMF; or 3. The wireless communication method of claim 2, further comprising at least one of: a forwarding indication indicating at least one PDU session to which the SMF change information applies;

4. The wireless communication method of claim 3 , wherein the forwarding indication indicates a single PDU session or multiple PDU sessions serviced by the second SMF.

5. Taking over control of the PDU session served by the second SMF comprises: The wireless communication method according to any one of claims 1 to 4, further comprising receiving a request from a user plane function from the second SMF to take over control of a packet forwarding control protocol session corresponding to the PDU session.

6. The wireless communication method according to any one of claims 1 to 5, wherein the at least one network function includes at least one of an access and mobility management function, a policy control function, an integrated data management, an intermediate SMF, or a visited SMF.

7. the at least one network function includes a policy control function; The wireless communication method according to any one of claims 1 to 6, wherein the SMF change information sent to the policy control function further includes a notification uniform resource identifier of a recipient of a session management policy update notification.

8. 1. A wireless communication method for use in an intermediate session management function (SMF), comprising: receiving, from a first SMF, SMF modification information associated with a protocol data unit (PDU) session serviced by a second SMF; and transmitting the SMF change information to an access and mobility management function associated with the PDU session.

9. The wireless communication method according to claim 8 , wherein the SMF modification information includes an identifier of the first SMF.

10. The SMF change information is an identifier of the second SMF; an identifier of a first SMF set that includes the first SMF; an identifier of a second SMF set that includes the second SMF; or 10. The wireless communication method of claim 9, further comprising at least one of: a forwarding indication indicating at least one PDU session to which the SMF modification information applies;

11. The wireless communication method of claim 10, wherein the forwarding indication indicates a single PDU session or multiple PDU sessions serviced by the second SMF.

12. A wireless communication method for network functionality, comprising: receiving, from a first session management function (SMF), SMF modification information associated with a protocol data unit (PDU) session serviced by a second SMF; A wireless communication method comprising: updating SMF information of at least one PDU session based on the SMF change information.

13. The wireless communication method according to claim 12, wherein the SMF modification information includes an identifier of the first SMF.

14. The SMF change information is an identifier of the second SMF; an identifier of a first SMF set that includes the first SMF; an identifier of a second SMF set that includes the second SMF; or 14. The wireless communication method of claim 13, further comprising at least one of: a forwarding indication indicating at least one PDU session to which the SMF modification information applies;

15. The wireless communication method of claim 14, wherein the forwarding indication indicates a single PDU session or multiple PDU sessions serviced by the second SMF.

16. The SMF modification information includes a forwarding instruction indicating a single PDU session or does not include the forwarding instruction; Updating the SMF information of the at least one PDU session based on the SMF change information A wireless communication method according to any one of claims 12 to 15, comprising updating the SMF information of the PDU session based on the SMF change information.

17. The SMF modification information includes a forwarding instruction indicating a plurality of PDU sessions serviced by the second SMF; Updating the SMF information of the at least one PDU session based on the SMF change information A wireless communication method according to any one of claims 12 to 15, comprising updating the SMF information of the plurality of PDU sessions served by the second SMF based on the SMF change information.

18. The wireless communication method according to any one of claims 12 to 17, wherein the network functions include at least one of an access and mobility management function, a policy control function, or an integrated data management function.

19. the network functions include access and mobility management functions; A wireless communication method according to any one of claims 12 to 18, wherein the SMF change information is received via an intermediate SMF.

20. the network function includes a policy control function; The wireless communication method according to any one of claims 12 to 19, wherein the SMF change information further includes a notification uniform resource identifier of a recipient of the session management policy update notification.

21. A wireless device having a first session management function (SMF), a processor configured to take over control of a protocol data unit (PDU) session served by a second SMF; A wireless device comprising: a communication unit configured to transmit SMF change information associated with the PDU session to at least one network function associated with the PDU session.

22. The wireless device of claim 21, wherein the processor is further configured to perform a wireless communication method according to any one of claims 2 to 7.

23. A wireless device having an intermediate session management function (SMF), receiving, from the first SMF, SMF change information associated with a protocol data unit (PDU) session serviced by the second SMF; configured to transmit the SMF change information to an access and mobility management function associated with the PDU session; A wireless device comprising a communication unit.

24. The wireless device of claim 23, further comprising a processor configured to perform the wireless communication method of any one of claims 9 to 11.

25. A wireless device having a network function, a communication unit configured to receive, from a first session management function (SMF), SMF change information associated with a protocol data unit (PDU) session serviced by a second SMF; A wireless device comprising: a processor configured to update SMF information of at least one PDU session based on the SMF change information.

26. The wireless device of claim 25, wherein the processor is further configured to perform a wireless communication method according to any one of claims 13 to 20.

27. A computer program product comprising computer readable program medium code stored thereon, the code, when executed by a processor, causing the processor to implement a wireless communication method according to any one of claims 1 to 20.

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