CN117597978A

CN117597978A - Method for repositioning session management function

Info

Publication number: CN117597978A
Application number: CN202180097911.9A
Authority: CN
Inventors: 朱进国; 李志军
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2021-05-06
Filing date: 2021-05-06
Publication date: 2024-02-23
Also published as: WO2022232999A1

Abstract

A wireless communication method for a first session management function is disclosed, the method comprising receiving a context creation request for a protocol data unit session from an access and mobility management function, wherein the context creation request comprises first wireless terminal location information associated with a first wireless communication node, sending a session context request associated with the protocol data unit session to a second session management function, and receiving a session context associated with the protocol data unit session from the second session management function, wherein the session context comprises second wireless terminal location information associated with a second wireless network node.

Description

Method for repositioning session management function

Technical Field

The present invention relates generally to wireless communications.

Background

For different reasons, the intermediate session management function (Intermediate Session Management Function, I-SMF) of the User Equipment (UE) may be relocated. For example, the serving I-SMF may be relocated when the UE moves outside the serving area of the serving SMF/I-SMF, when the serving I-SMF is not suitable for serving network slices, and/or when the serving I-SMF does not support the requested data network access identity (Data Network Access Identification, DNAI). During I-SMF relocation, some information (e.g., channel configuration) may be used to be reused to reduce signal overhead. However, it is unclear what kind of information should be reused and when it should be reused.

Disclosure of Invention

The present invention relates to methods, systems, and devices for SMF relocation, and in particular to I-SMF relocation.

The present disclosure relates to a wireless communication method for use in a first session management function, the method comprising: receiving a context creation request for a protocol data unit session from an access and mobility management function, wherein the context creation request comprises first wireless terminal location information associated with a first wireless communication node; sending a session context request associated with the protocol data unit session to a second session management function; a session context associated with the protocol data unit session is received from the second session management function, wherein the session context includes second wireless terminal location information associated with a second wireless network node.

Various embodiments may preferably implement the following features:

preferably, the first wireless terminal location information and the second wireless terminal location information are the same, the session context further comprising tunnel information associated with an interface between the second wireless network node and the first user plane function, the method further comprising at least one of: and using the tunnel information of the protocol data unit session or sending the tunnel information to a second user plane function.

Preferably, the tunnel information comprises at least one of an internet protocol address or a tunnel endpoint identifier of a protocol data unit session in the second wireless communication node.

Preferably, the first wireless terminal position information and the second wireless terminal position information are the same, the method further comprising: a request to modify a session context associated with a protocol data unit session is sent to an access and mobility management function.

Preferably, the first wireless terminal position information and the second wireless terminal position information are different, the method further comprising: a request to establish a session context associated with a protocol data unit session is sent to an access and mobility management function.

Preferably, the first wireless terminal position information and the second wireless terminal position information include at least one of: tracking area identity, new radio cell identity or global radio access network node identity.

The present disclosure relates to a wireless communication method for a second session management function, the method comprising:

receiving a session context request associated with a protocol data unit session from a first session management function; a session context is sent to the first session management function, the session context comprising second wireless terminal location information associated with a second wireless network node.

Various embodiments may preferably implement the following features:

preferably, the wireless communication method further comprises receiving second wireless terminal location information from the access and mobility management function.

Preferably, the second wireless terminal location information includes at least one of: tracking area identity, new radio cell identity or global radio access network node identity.

Preferably, the session context further comprises tunnel information associated with an interface between the second radio network node and the first user plane function.

Preferably, the wireless communication method further comprises receiving tunnel information from the access and mobility management functions.

The present disclosure relates to a wireless communication method for use in a first session management function, the method comprising receiving a context creation request for a protocol data unit session from an access and mobility management function, wherein the context creation request comprises an indication associated with validity of session information in a second wireless network node of the protocol data unit session.

Various embodiments may preferably implement the following features:

preferably, the indication indicates that session information in a second radio network node of the protocol data unit session is valid; the method further comprises the steps of: a session context request associated with the protocol data unit session is sent to a second session management function, wherein the session context request includes an indication requesting tunnel information associated with an interface between the second wireless network node and a first user plane function.

Preferably, the indication indicates that session information in the second radio network node of the protocol data unit session is valid, wherein the method further comprises: receiving a session context for the protocol data unit session from a second session management function, wherein the session context comprises tunnel information associated with an interface between the second radio network node and a first user plane function, wherein the method further comprises at least one of: and using the tunnel information of the protocol data unit session or sending the tunnel information to a second user plane function.

Preferably, the indication indicates that session information in the second radio network node of the protocol data unit session is valid, the method further comprising: a request to modify the session context associated with the protocol data unit session is sent to the access and mobility management function.

Preferably, the indication indicates that session information in the second radio network node of the protocol data unit session is not valid, and wherein the method further comprises: a request to establish the session context associated with the protocol data unit session is sent to the access and mobility management function.

The present disclosure relates to a wireless communication method for use in an access and mobility management function, the method comprising transmitting a context creation request for a protocol data unit session to a first session management function, wherein the context creation request comprises an indication associated with validity of session information in a second wireless network node of the protocol data unit session.

Various embodiments may preferably implement the following features:

preferably, the indication indicates that session information in the second radio network node of the protocol data unit session is valid, the method further comprising: receiving a request from a first session management function to modify a session context associated with a protocol data unit session;

Preferably, the indication indicates that session information in the second radio network node of the protocol data unit session is not valid, the method further comprising: a request is received from the first session management function to establish the session context associated with the protocol data unit session.

The present disclosure relates to a wireless device including a first session management function, the wireless device comprising:

a communication unit for receiving a context creation request for a protocol data unit session from an access and mobility management function, wherein the context creation request comprises first wireless terminal location information associated with a first wireless communication node; sending a session context request associated with the protocol data unit session to a second session management function; a session context associated with the protocol data unit session is received from the second session management function, wherein the session context includes second wireless terminal location information associated with a second wireless network node.

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.

The present disclosure relates to a wireless device including a second session management function, the wireless device comprising:

a communication unit for receiving a session context request associated with a protocol data unit session from a first session management function; a session context is sent to the first session management function, the session context comprising second wireless terminal location information associated with a second wireless network node.

Various embodiments may preferably implement the following features:

The present disclosure relates to a wireless device including a first session management function, the wireless device comprising: a communication unit for receiving a context creation request for a protocol data unit session from an access and mobility management function, wherein the context creation request comprises an indication associated with validity of session information in a second radio network node of the protocol data unit session.

Various embodiments may preferably implement the following features:

The present disclosure relates to wireless devices that include access and mobility management functions. The wireless device comprises a communication unit configured to transmit a context creation request for a protocol data unit session to a first session management function, wherein the context creation request comprises an indication associated with validity of session information in a second wireless network node of the protocol data unit session.

Various embodiments may preferably implement the following features:

The present disclosure relates to a computer program product comprising computer readable program code stored thereon, which when executed by a processor causes the processor to implement a wireless communication method as described in any of the preceding methods.

The exemplary embodiments of the present disclosure are intended to provide features that become 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. However, it should be understood that these embodiments are presented by way of example and not limitation, and that various modifications of the disclosed embodiments may be made and remain within the scope of the disclosure, as will be apparent to those of ordinary skill in the art from reading the disclosure.

Thus, the disclosure is not limited to the exemplary embodiments and applications described and illustrated. Furthermore, the particular order and/or hierarchy of steps in the methods of the present disclosure are exemplary approaches. Based on design preferences, the specific order or hierarchy of steps in the disclosed methods or processes may be rearranged while remaining within the scope of the present disclosure. As such, those of skill in the art will understand that the methods and techniques disclosed in this disclosure present different steps or acts in a sample order, and that the present invention is not limited to the particular order or hierarchy presented, unless explicitly stated otherwise.

The above and other aspects and implementations thereof are described in more detail in the accompanying drawings, description and claims.

Drawings

Fig. 1 shows a schematic diagram of a 5 th generation system (5 GS) architecture according to an embodiment of the present disclosure.

Fig. 2 shows a schematic diagram of a method according to an embodiment of the present disclosure.

Fig. 3 shows a schematic diagram of a method according to an embodiment of the present disclosure.

Fig. 4 shows a schematic diagram of a method according to an embodiment of the present disclosure.

Fig. 5 shows a flow chart of a method according to an embodiment of the present disclosure.

Fig. 6 shows a flow chart of a method according to an embodiment of the present disclosure.

Fig. 7 shows a flow chart of a method according to an embodiment of the present disclosure.

Fig. 8 shows a flow chart of a method according to an embodiment of the present disclosure.

Fig. 9 shows an example of a schematic diagram of a wireless terminal according to an embodiment of the present disclosure.

Fig. 10 shows an example of a schematic diagram of a wireless network node according to an embodiment of the present disclosure.

Detailed Description

Fig. 1 shows a schematic diagram of a 5 th generation system (5 GS) architecture according to an embodiment of the present disclosure. The network functions shown in fig. 1 are as follows:

ue: a user equipment.

Ran: (radio access network):

the radio access network (Radio Access Network, RAN) node provides a Uu (radio) interface towards the UE, an N2 interface towards the AMF (Control Plane, CP) and an N3 interface towards the UPF (User Plane, UP).

Amf (access and mobility management function):

the AMF includes the following functions: registration management, connection management, reachability management, and mobility management. The AMF also performs access authentication and access authorization. The AMF is a Non-Access Stratum (NAS) secure terminal, and relays SM NAS between the UE and the SMF, and so on. In addition, the AMF performs an SMF/I-SMF selection function during a Packet Data Unit (PDU) session establishment procedure and a UE mobility procedure.

Smf (session management function):

the session management function (Session Management Function, SMF) includes the following functions: session establishment, modification and release, UE IP address allocation and management (including optional authorization functions), selection and control of UP functions, downlink data notification, etc. The SMF service domain is a set of UPF service domains for all UPFs that the SMF can control.

5.I-SMF (intermediate SMF):

I-SMF is inserted, changed or removed from the PDU session when the UE moves outside the service area of the serving SMF/I-SMF. The I-SMF has an N16a interface towards the SMF and an N11 interface towards the AMF. Based on the UE mobility, the I-SMF may be relocated from the source I-SMF to the target I-SMF. The target I-SMF may retrieve the session related context from the source I-SMF via the N38 interface.

Upf (user plane function):

the user plane functions (User plane function, UPF) are controlled by the SMF over the N4 interface. The UPF includes the following functions: acting as anchor points for mobility within/between radio access technologies (Radio Access Technology, RATs), packet routing and forwarding, traffic usage reporting, quality of service (Quality Of Service, QOS) handling of the user plane, downlink packet buffering and downlink data notification triggering, etc. A UPF service area is an area comprised of one or more tracking areas within which a RAN node may service PDU sessions associated with a UPF via an N3 interface between the RAN and the UPF without adding a new UPF or removing/reassigning a UPF therebetween. The Anchor UPF (A-UPF) remains unchanged during UE mobility.

7.I-UPF (intermediate UPF):

when the UE moves outside the a-UPF service area, the I-UPF is inserted/relocated. The I-UPF uses an N3 tunnel to connect RAN nodes and an N9 tunnel to connect a-UPF. The I-UPF may also provide traffic offload functions to route the identified uplink traffic to the local data network.

8. Data network: the data network provides data services such as operator services, internet access services, third party services, and the like.

During UE mobility, the AMF may determine that an I-SMF needs to be inserted, relocated, or removed from the PDU session. The target I-SMF may retrieve the session-related context from the source I-SMF. The session related context includes the following information:

1. the SMF-related context includes PDU session identification, network slice related information, SMFID, UPF N9 tunnel information, QOS flow related information, and the like. Note that in the existing standard specification, RAN N3 tunnel information is not transferred to the target I-SMF.

AMF related information, including AMF ID.

The target I-SMF re-establishes the user plane of the PDU session using the session context information.

During relocation of the I-SMF, the RAN N3 tunnel information is available for reuse when the UE is in a connected state. While the source I-SMF does not provide RAN N3 tunnel information to the target I-SMF in the session related context.

Furthermore, even though RAN N3 tunnel information is provided to the target I-SMF, the target I-SMF may not know whether the provided RAN N3 tunnel information can be reused for the PDU session. In addition, the target I-SMF cannot distinguish whether to establish a new session context in the RAN node or to update an existing session context in the RAN node.

In order to solve the problems, the invention provides the following technical scheme:

1. the source I-SMF provides RAN N3 tunnel information and/or associated UE location information to the target I-SMF in a session related context.

2. The target I-SMF determines whether to reuse RAN N3 tunnel information based on the associated UE location information.

Fig. 2 shows a schematic diagram of a process according to an embodiment of the present disclosure. The procedure shown in fig. 2 may be applied in the scenario where a packet data network (Packet Data Network, PDN) connection is handed over from an evolved packet system (Evolved Packet System, EPS) to 5 GS. Furthermore, the procedure shown in fig. 2 illustrates how the I-SMF is relocated during the UE registration procedure. For the home routing case, the I-SMF may be replaced by a visited SMF (V-SMF), and the I-UPF may be replaced by a visited UPF (V-UPF). The process shown in fig. 2 may be used in the network architecture shown in fig. 1, including the following steps.

In step 201, the UE establishes a PDN connection (i.e., EPS) with a home route in the 4G network. The UE moves to the area of the 5G network and performs a EPS to 5GS handover procedure. During the EPS to 5GS handoff, the AMF selects a default I-SMF1 based on Single network slice selection assistance information (Single-Network Slice Selection Assistant Information, S-NSSAI) configured for interworking, and uses the I-SMF1 for PDU sessions. The SMF allocates and provides the correct S-nsai for the PDU session to the AMF.

In step 202, after the EPS to 5GS handover procedure, the UE initiates a UE registration procedure via the RAN node. The UE is in a connected state. The RAN has an active UE context and an N3 tunnel between the RAN node and I-UPF1 has been established during the EPS to 5GS handover procedure.

In step 203, the AMF determines that I-SMF1 is not suitable for the PDU session based on the S-NSSAI of the PDU session received from the SMF. In this case, the AMF reselects I-SMF2 for the PDU session, and initiates an I-SMF relocation procedure by invoking Nsmf to create an SM context request message to the I-SMF 2. The Nsmf creates the SM context request message including: PDU session ID, SM context ID, S-NSSAI, UE location information, access type, RAT type, and operation type. The SM context ID points to I-SMF1. The AMF sets the operation type to "UP active" to indicate that N3 tunnel user plane resources are established for the PDU session. The AMF determines the access type and the RAT type based on a global RAN node ID associated with the N2 interface.

In one embodiment, the AMF determines that the RAN node of the PDU session is unchanged and that the session context in the RAN node is valid. The AMF provides an indication to the I-SMF2 based on the determination. The indication may be used by I-SMF2 to determine whether the session context in the RAN node is valid, e.g., for reuse.

In step 204, I-SMF2 retrieves the SM context from I-SMF1 by invoking an Nsmf PDU session context request message, for example. Including SM context type, SM context ID, etc.). For example, I-SMF2 may use the SM context ID received from the AMF for the service operation. The SM context ID is used for the receiver of the Nsmf PDU session context _ request to determine the target PDU session. The SM context type indicates that the requested information includes all SM contexts, i.e., PDN connection context and 5GSM context. The I-SMF2 may also send an indication request RANN3 tunnel information to the I-SMF1 if the I-SMF2 determines that the session context in the RAN node is valid.

In step 205, I-SMF1 responds to I-SMF2 with the indicated SM context for the PDU session. When the UE is in a connection management connected (cm_connected) state (e.g., RRC connected state or RRC inactive state), the SM context may include session information associated with the RAN node. For example, the session information includes RANN3 tunnel information and/or UE location information. The RANN3 tunnel information includes the IP address and tunnel endpoint identification of the RAN node for the PDU session. The UE location information may include a tracking area identity (Tracking Area Identity, TAI), and/or an NR cell identity, and/or a global RAN node identity. UE location information is provided by the AMF and is saved in the I-SMF1 when the PDU session is handed over from EPS. The SM context may also include the S-nsai of the PDU session (i.e., S-nsai configured for interworking).

In step 206, I-SMF2 selects a new I-UPF (i.e., I-UPF 2). For example, I-SMF2 selects a new I-UPF (e.g., S-NSSAI and/or UE location information) to receive from the AMF based on the received SM context. The I-SMF2 initiates an N4 session setup to the new I-UPF.

In one embodiment, the I-SMF2 determines whether session information in the RAN node (e.g., associated with the RAN node) is valid based on the UE location information and/or S-nsai of the PDU session. For example, when a corresponding network slice of a PDU session changes, the I-SMF2 may determine that session information associated with the RAN node is not valid. Alternatively or additionally, if the UE location information received from the AMF and the UE location information received from the I-SMF1 are the same (even if the network slices are different), the I-SMF2 may determine that session information associated with the RAN node is still valid and/or RANN3 tunnel information received from the I-SMF1 may be reused.

If the session information associated with the RAN node is valid and the RAN N3 tunnel information is reused, the I-SMF2 provides the RAN N3 tunnel information to the I-UPF2 and the I-UPF2 provides the I-UPF N3 tunnel information and the I-UPF N9 tunnel information to the I-SMF 2.

In step 207, I-SMF2 invokes an SMF-oriented NSmf PDU session update request (e.g., including SM context ID, I-UPF DL tunnel information, SM context ID at I-SMF2, access type, RAT type). I-SMF2 uses the SM context ID received from I-SMF1 for this service operation.

In step 208, the SMF initiates an N4 session modification to the PDU session anchor (PDU Session Anchor, PSA) UPF. The SMF provides the PSA UPF with I-UPF N9 tunnel information.

In step 209, the SMF responds to I-SMF2 with an Nsmf PDU session update response.

In step 210, I-SMF2 sends an Nsmf PDU session creation SM context response (e.g., including N2SM information (e.g., PDU session ID, QFI, QOS profile, CNN3 tunnel information, S-NSSAI), N1SM container, reason) to the AMF. The CNN3 tunnel information (Info) is I-UPF N3 tunnel information of I-UPF 2. If the session information associated with the RAN node is valid, the N2SM information includes a request to modify the session information associated with the RAN node; otherwise, the N2SM information includes a request to establish a new session context in the RAN node.

In step 211, the AMF sends a registration accept (message) to the UE, wherein the registration accept (message) comprises the new allowed nsai and/or the new registration area.

In step 212, the AMF sends an N2 request (N2 SM information received from the SMF, security context, mobility restriction list) to the RAN node. The N2SM information includes I-UPF N3 tunnel information of I-UPF 2.

In step 213, the uplink data may be sent to the I-UPF2 and then forwarded to the UPF.

In step 214, the RAN sends AN N2 request acknowledgement (list of PDU sessions established with N2 SM information (AN tunnel information)) to the AMF. When the RAN determines to change old RAN N3 tunnel information associated with the old network slice, the N2 request acknowledgment message may include new N2 SM information.

In step 215, the AMF sends an Nsmf PDU session update SM context request (N2 SM information, RAT type, access type) per PDU session to the I-SMF 2. The N2 SM information may include new RAN N3 tunnel information.

In step 216, I-SMF2 may update the new RAN N3 tunnel information to I-UPF2 during the N4 session update procedure.

SMF2 sends an Nsmf PDU session update SM context response to the AMF.

In step 218, the downlink data may be sent to the RAN node through a new N3 tunnel.

AMF sends Nsmf release SM context request message to I-SMF1 to release the resources of the PDU session.

In step 220, I-SMF1 releases PDU session resources in I-UPF 2.

In step 221, I-SMF1 sends an Nsmf release SM context response (message) to the AMF.

Fig. 3 shows a schematic diagram of a process according to an embodiment of the present disclosure. In the procedure shown in fig. 3, a PDU session is established via a RAN node (e.g., RAN node), RAN1 is inserted with an I-SMF (e.g., I-SMF 1), and the UE moves to a radio resource control (Radio Resource Control, RRC) inactive state. Next, the UE moves to a service area of another RAN node (e.g., RAN 2) and initiates a UE registration procedure via RAN 2. Under such conditions, the I-SMF for the PDU session is relocated (e.g., to another I-SMF (e.g., I-SMF 2)).

Specifically, the UE accesses the network through the RAN1 and establishes PDU session with the I-SMF1 in the control plane. The RAN1 node may decide that the UE enters an RRC inactive state and release the RRC connection on the Uu interface while maintaining the UE context in the RAN 1. Note that the UE status in the AMF may still be connected mode. In addition, the N3 tunnel may also be maintained in both RAN1 and I-UPF1 (step 301).

In step 302, the UE remains in an RRC inactive state and moves outside of the registration area. In this case, the UE initiates the UE registration procedure through the new RAN node RAN 2.

In step 303, RAN2 may obtain a UE context containing AMF information from RAN1 and forward the registration request message to the AMF. RAN2 may select the old AMF or select another new AMF.

In step 304, the AMF determines that I-SMF1 is not suitable for the PDU session based on the current UE location. Thus, AMF reselects I-SMF2 for the PDU session, initiates an I-SMF relocation procedure by invoking Nsmf to create an SM context request to I-SMF 2. The message includes a PDU session ID, an SM context ID, an S-NSSAI, UE location information, an access type, a RAT type, an operation type. The SM context ID points to I-SMF1. The AMF sets the operation type to "UP active" to indicate that N3 tunnel user plane resources are established for the PDU session. The AMF determines the access type and RAT type based on a global RAN node ID associated with the N2 interface.

If the RAN2 selects a new AMF, the new AMF retrieves the UE context from the old AMF. In the UE environment, the old AMF may include old RAN1 information if the UE is in a connected state. The new AMF then determines that the RAN node changed and the session context in the old RAN node is invalid. AMF may provide an indication to I-SMF 2. The I-SMF2 may use the indication to determine whether the session context in the RAN node is valid.

In step 305, I-SMF2 obtains the SM context from I-SMF1 by invoking an NSmf PDU session context request (SM context type, SM context ID). The I-SMF2 uses the SM context ID received from the AMF for the service operation. The SM context ID is used for the receiver of the Nsmf PDU session context request to determine the target PDU session. The SM context type indicates that the requested information is all SM contexts, i.e. the SM context. PDN connectivity context and 5GSM context.

In step 306, I-SMF1 responds to I-SMF1 with the indicated SM context for the PDU session. The SM context may include session information associated with the RAN node when the UE is in a CM connected state. For example, the session information may include RAN1N3 tunnel information and/or UE location information. The RAN1N3 tunnel information includes an IP address and a tunnel endpoint identifier in the RAN1 node of the PDU session. The UE location information may include TAI or NR cell identity or global RAN node identity. UE location information is provided by the AMF and stored in the I-SMF1. The SM context may also contain the S-nsai of the PDU session.

In step 307, I-SMF2 selects a new I-UPF (i.e., I-UPF 2). For example, I-SMF2 selects I-UPF2 based on a received SM context (e.g., S-NSSAI) and/or UE location information received from an AMF. The I-SMF2 initiates an N4 session setup to the selected I-UPF2.

In one embodiment, the I-SMF2 may determine whether session information associated with the RAN node is valid based on the UE location information. For example, if the UE location information received from the AMF is not the same as the UE location information received from the I-SMF1, the I-SMF2 may determine that the session information is invalid and no longer use the RAN N3 tunnel information. Alternatively, the I-SMF2 may determine whether session information associated with the RAN node is valid based on an indication from the AMF, as described in step 304.

If session information associated with the RAN node is invalid and the RANN3 tunnel information is not reused, then the I-SMF2 does not provide the RAN N3 tunnel information to the I-UPF2.

In step 308, I-SMF2 invokes an NSmf PDU session update request (SM context ID, new I-UPF DL tunnel information, SM context ID at I-SMF, access type, RAT type) towards SMF. I-SMF2 uses the SM context ID at the SMF received from I-SMF1 for the service operation.

In step 309, the SMF initiates an N4 session modification to the PDU session anchor UPF. The SMF provides the PSA UPF with new I-UPF N9 tunnel information.

In step 310, the SMF responds to I-SMF2 with an Nsmf PDU session update response.

In step 311, I-SMF2 sends an Nsmf PDU session creation SM context response (N2 SM information (PDU session ID, QFI, QOS profile, CNN3 tunnel information, S-NSSAI), N1 SM container, reason) to the AMF. The CN N3 tunnel information is the I-UPF N3 tunnel information of the new I-UPF 2. If the session information associated with the RAN node is not valid, the N2SM information includes a request to establish a new session context associated with the RAN node.

In step 312, the AMF sends a registration accept to the UE, the registration accept including the new allowed NSSAI, the new registration area.

In step 313, the AMF transmits an N2 request (e.g., N2SM information, security context, and/or mobility restriction list received from the SMF) to the RAN. The N2SM information includes I-UPF N3 tunnel information for the new I-UPF 2.

In step 314, the uplink data may be sent to the new I-UPF2 and then forwarded to the UPF.

In step 315, the RAN sends an N2 request acknowledgement (e.g., including a list of PDU sessions to be established with N2SM information (RAN N3 tunnel information)) to the AMF. RAN2 allocates RAN N3 tunnel information for the PDU session and transmits the RAN N3 tunnel information to I-SMF2 in N2SM information.

In step 316, the AMF sends an Nsmf PDU session update SM context request per PDU session (N2 SM information, RAT type, access type) to the I-SMF2. The N2 SM information includes new RAN N3 tunnel information.

In step 317, I-SMF2 may update I-UPF2 with the new RAN N3 tunnel information during the N4 session update procedure.

In step 318, the I-SMF sends an Nsmf PDU session update SM context_response to the AMF.

In step 319, downlink data may be sent to the RAN node through the new N3 tunnel.

In step 320, the AMF determines to release the UE context in the old RAN 1. The AMF sends N2 UE context release requests to RAN 1.

In step 321, RAN1 releases the UE context and sends N2 UE context release completions to the AMF.

In step 322, the AMF sends an Nsmf release SM context request to the I-SMF1, releasing the resources of the PDU session.

In step 323, I-SMF1 releases the PDU session resources in I-UPF2.

In step 324, I-SMF1 sends an NSmf release SM context response to the AMF.

Fig. 4 shows a schematic diagram of a process according to an embodiment of the present disclosure. In fig. 4, a PDU session is established with I-SMF1 insertion and an application function (Application Function, AF) initiates an influential request procedure to offload traffic into a local DN identified by DNAI. I-SMF1 does not support the requested DNAI and requires relocation of the I-SMF for the PDU session.

Specifically, the UE establishes a PDU session at 5GS with I-SMF1 inserted into the control plane. The AF then sends a message to the 5G core network affecting the traffic routing of the local data network identified by DNAI. The policy control function (Policy Control Function, PCF) sends PCC rules including DNAI for the PDU session to the SMF by invoking an Npcf SM policy control update notification service operation. Based on the received DNAI information, the SMF may subscribe to the AMF for UE mobility event notifications (e.g., notifications associated with the UE move in or out of the region of interest). The SMF determines a target DNAI applicable to the current UE location (step 401).

In step 402, if the SMF and associated I-SMF1 are unable to service the target DNAI, an Nsmf PDU session state notification message is invoked. The content of the Nsmf PDU session state notification message contains target DNAI information, which may indicate a desire to select I-SMF. This is to trigger the AMF to (re) select the appropriate I-SMF for the PDU session. Target DNA1 was used to select (I-) SMF, which controls UPF linked to target DNAI.

In step 403, the I-SMF invokes the Nsmf PDU session SM context state notification message to send the target DNAI information for the existing PDU session to the AMF.

In step 404, if it is desired to select I-SMF, the AMF selects I-SMF2 which may serve the target DNAI of the existing PDU session. The AMF initiates the I-SMF relocation procedure by invoking Nsmf create SM context request message to I-SMF2. The message includes a PDU session ID, SM context ID, UE location information, access type, RAT type, operation type. The SM context ID points to I-SMF1. The AMF sets the operation type to "UP active" to indicate that N3 tunnel user plane resources are established for the PDU session only when the UE is in a connected state. The AMF determines the access type and RAT type based on the global RAN node ID associated with the N2 interface.

When the UE is in a connected state, the AMF then determines that the RAN node is unchanged and that the session context in the RAN node is valid. The AMF then provides an indication to I-SMF2 based on the result. The I-SMF2 may use the indication to determine whether the session context in the RAN node is valid.

In step 405, I-SMF2 obtains the SM context from I-SMF1 by invoking an NSmf PDU session context request (SM context type, SM context ID). The I-SMF2 uses the SM context ID received from the AMF for the service operation. The SM context ID is used by the receiver of the Nsmf PDU session context request to determine the target PDU session. The SM context type indicates that the requested information is all SM contexts, i.e., PDN connection context and 5GSM context. The I-SMF2 may also send an indication to the I-SMF1 requesting RAN N3 tunnel information if the I-SMF2 determines that the session context in the RAN node is valid.

In step 406, I-SMF1 responds with the indicated SM context for the PDU session. The SM context of the PDU session may include session information associated with the RAN node if the UE is in a connected state. For example, the session information may include RAN N3 tunnel information and UE location information. The RAN N3 tunnel information includes the IP address and tunnel endpoint identification of the RAN node for the PDU session. The UE location information may include a tracking area identity (Tracking Area Identity, TAI), or NR cell identity or global RAN node identity. UE location information is provided by the AMF and stored in the I-SMF 1.

In step 407, I-SMF2 selects a new I-UPF2. For example, I-SMF2 selects a new I-UPF2 based on the received SM context (e.g., UE location information received from the AMF). The I-SMF2 initiates an N4 session setup to the new I-UPF2.

The I-SMF2 determines whether session information in the RAN node is valid according to the UE location information. For example, I-SMF2 may determine that session information associated with the RAN node is valid and determine to reuse RAN N3 tunnel information if the UE location received from the AMF is the same as the UE location information received from I-SMF 1.

If session information associated with the RAN node is valid and the RAN N3 tunnel information is reused, the I-SMF2 provides the RAN N3 tunnel information to the I-UPF2.I-UPF2 provides I-UPF N3 tunnel information and I-UPF N9 tunnel information to I-SMF 2.

In step 408, I-SMF2 invokes an SMF-oriented NSmf PDU session update request (e.g., including SM context ID, new I-UPFDL tunnel information, SM context ID at I-SMF, access type, RAT type, DNAI list supported by I-SMF 2). I-SMF2 uses the SM context ID at the SMF received from I-SMF1 for the service operation.

In step 409, the SMF initiates an N4 session modification to a PDU Session Anchor (PSA) UPF. The SMF provides the PSA UPF with new I-UPF N9 tunnel information.

In step 410, the SMF responds to I-SMF2 with an Nsmf PDU session update response (e.g., including DNAI, N4 information of interest for the PDU session). The SMF determines DNAI of interest for the PDU session based on the DNAI list supported by I-SMF2 in the PCC rules of the PDU session and the requested DNAI. The SMF provides the I-SMF with DNAI of interest for this PDU session for local traffic steering. The SMF generates N4 information for local traffic offload based on available DNAIs indicated by the I-SMF, PCC rules and charging requirements associated with these DNAIs. The SMF provides the I-SMF with N4 information to detect, enforce, monitor traffic in the UPF controlled by the I-SMF. The I-SMF uses the N4 information to derive rules installed in the I-UPF controlled by the I-SMF. Based on the DNAI of interest, I-SMF2 selects a local PSA UPF to access the local data network and sends N4 information to the local PSAUPF.

In step 411, downlink data may be sent to the RAN node through an N3 tunnel.

In step 412, the I-SMF2 sends an Nsmf PDU session creation SM context response (N2 SM information (e.g., including PDU session ID, QFI, QOS profile, CN N3 tunnel information, S-nsai), reason) to the AMF. The CN N3 tunnel information is the I-UPF N3 tunnel information of the new I-UPF 2. If the session information associated with the RAN node is valid, the N2SM information includes a request to modify a session context associated with the RAN node.

In step 413, the AMF transmits an N2 request (e.g., including N2SM information received from the SMF, security context, mobility restriction list) to the RAN. The N2SM information includes I-UPF N3 tunnel information for the new I-UPF 2.

In step 414, the uplink data may be sent to the new I-UPF2 and then forwarded to the UPF.

In step 415, the RAN transmits an N2 request acknowledgement (e.g., a list including PDU sessions established with N2SM information) to the AMF.

In step 416, the AMF transmits an Nsmf PDU session update SM context request (e.g., including N2SM information, RAT type, access type) per PDU session to the SMF.

In step 417, the I-SMF sends an Nsmf PDU session update SM context response to the AMF.

In step 418, the AMF sends an Nsmf release SM context request to the I-SMF1, releasing the resources of the PDU session.

In step 419, I-SMF1 releases PDU session resources in I-UPF 1.

In step 420, I-SMF1 sends an NSmf release SM context response to the AMF.

Fig. 5 shows a flow chart of a method according to an embodiment of the present disclosure. The method shown in fig. 5 may be used in a first (intermediate) SMF (e.g., target I-SMF, I-SMF2 described above, including/first wireless device performing the functions of I-SMF/SMF) and comprises the following steps.

Step 501: a context creation request for a PDU is received from an AMF.

Step 502: a session context request associated with the PDU is sent to a second SMF.

Step 503: a session context associated with the PDU is received from the second SMF.

In fig. 5, a first SMF receives a context creation request for a PDU session, wherein the context creation request includes first wireless terminal location information (e.g., UE location information) associated with a first wireless communication node. For example, the first radio network node may be selected (via AMF) for the PDU session. The first SMF sends a session context request associated with the PDU session to the second SMF to retrieve a session context of the PDU session from the second SMF. Next, the first SMF receives a session context from the second SMF. In this embodiment, the received session context includes second wireless terminal location information associated with the second wireless network node. For example, the second radio network node may be an old serving network node of the PDU session. Based on the first wireless terminal location information and the second wireless terminal location information, the first SMF determines whether there is session information (e.g., N3 tunnel information associated with the wireless network node of the PDU session may be reused).

In one embodiment, the first wireless terminal location information and the second wireless terminal location information are the same (i.e. the first wireless network node is the second wireless network node). That is, session information associated with wireless network nodes of a PDU session may be available for reuse. In this case, the first SMF transmits a request to modify a session context associated with the PDU session to the AMF (e.g., step 210 or 412).

In one embodiment, the first wireless terminal location information and the second wireless terminal location information are different (i.e. the first wireless network node is not the second wireless network node). That is, session information associated with the wireless network node of the PDU session cannot be reused. In this embodiment, the first SMF transmits a request to establish a new session context associated with the PDU session to the AMF (e.g., step 210 or 311).

In one embodiment, the received session context includes tunnel information having an interface (e.g., an N3 tunnel/interface) between the second wireless network node and the first UPF, and the first wireless terminal location information and the second wireless terminal location information are the same. In this embodiment, the first SMF may use tunnel information of the PDU session, for example, for subsequent communications. Alternatively or additionally, the first SMF may send the tunnel information to the second UPF.

In one embodiment, the tunnel information includes at least one of an internet protocol address or a tunnel endpoint identifier of the PDU session in the second wireless communication node.

In one embodiment, the first/second wireless terminal location information comprises at least one of a tracking area identity, a new radio cell identity or a global radio access network node identity.

Fig. 6 shows a flow chart of a method according to an embodiment of the present disclosure. The method shown in fig. 6 may be used in a second (intermediate) SMF (e.g., source I-SMF, I-SMF1 described above, or a second wireless device) that performs/includes the functions of the SMF/I-SMF and includes the following steps.

Step 601: a session context request associated with a PDU session is received from a first SMF.

Step 602: a session context associated with the PDU session is communicated to the first SMF.

In fig. 6, a second SMF receives a session context request associated with a PDU session from a first SMF. In response to the session context request, the second SMF sends a session context for the PDU session to the first SMF. Note that the session context includes second wireless terminal location information associated with the second wireless network node as a reference to whether to reuse session information associated with the wireless network node of the PDU session.

In one embodiment, second wireless terminal location information is received from an AMF.

In one embodiment, the second wireless terminal location information comprises at least one of a tracking area identity, a new radio cell identity or a global radio access network node identity.

In one embodiment, the transmitted session context further includes tunnel information (e.g., N3 tunnel information) associated with an interface between the second wireless network node and the first user plane function.

In one embodiment, tunnel information is received from an AMF.

Fig. 7 shows a flow chart of a method according to an embodiment of the present disclosure. The method shown in fig. 7 may be used for a first SMF (e.g., I-SMF 2) and comprises the steps of:

step 701: receiving a context creation request of a PDU session sent by an AMF; the context creation request includes an indication associated with validity of session information in a second wireless network node of the PDU session.

In fig. 7, a first SMF receives a context creation request for a PDU session from an AMF. In this embodiment, an indication associated with the validity of session information in the second wireless network node of the PDU session is included in the context creation request. Based on the indication, the first SMF determines whether session information in the second radio network node of the PDU session is valid and/or whether to reuse session information in the second radio network node of the PDU session.

In an embodiment, the indication indicates that session information in the second radio network node of the protocol data unit session is valid. In this embodiment, the first SMF sends a session context request associated with the PDU session to the second SMF; the session context request includes an indication requesting tunnel information associated with an interface between a second wireless network node and a first UPF of the PDU session.

In one embodiment, the indication indicates that session information in the second radio network node of the protocol data unit session is valid. In this embodiment, the first SMF receives (retrieves) a session context for the PDU session from the second SMF, wherein the session context includes tunnel information (e.g., N3 tunnel information) associated with an interface between the second wireless network node and the first UPF. The first SMF may use (e.g., reuse) tunnel information for the PDU session and/or send the tunnel information to the second UPF.

In one embodiment, the tunnel information includes at least one of an IP address or a tunnel endpoint identifier of the PDU session in the second wireless communication node.

In an embodiment, the indication indicates that session information in the second radio network node of the PDU session is valid. In this embodiment, the first SMF may send a request to the AMF to modify a session context associated with the PDU session.

In one embodiment, the indication indicates that session information in the second wireless network node of the PDU session is not valid. In this case, the first SMF sends a request to the AMF to modify a session context associated with the PDU session.

Fig. 8 shows a flow chart of a method according to an embodiment of the present disclosure. The method shown in fig. 8 may be used in an AMF and comprises the steps of:

step 801: transmitting a context creation request for the PDU session to the first SMF; the context creation request includes an indication associated with validity of session information in a second wireless network node of the PDU session.

In fig. 8, the AMF may select a first SMF for the PDU session (e.g., due to UE mobility) and send a context creation request for the PDU session to the first SMF. In this embodiment, an indication associated with the validity of session information in the second wireless network node of the PDU session is included in the context creation request. For example, the AMF may generate the indication based on whether the second wireless communication node of the PDU session has changed.

In an embodiment, the indication indicates that session information in the wireless network node of the PDU session is valid (e.g., the wireless network node of the PDU session is unchanged). In this case, the AMF may receive a request from the first SMF to modify a session context associated with the protocol data unit session.

In an embodiment, the indication indicates that session information in the wireless network node of the PDU session is not valid (e.g., the wireless network node of the PDU session changes). In this embodiment, the AMF may receive a request from the first SMF to establish a session context associated with the protocol data unit session.

Fig. 9 relates to a schematic diagram of a wireless terminal 90 according to an embodiment of the present disclosure. The wireless terminal 90 may be a User Equipment (UE), a mobile phone, a notebook computer, a tablet computer, an electronic book, or a portable computer system, which is not limited herein. The wireless terminal 90 may include a processor 900, such as a microprocessor or application specific integrated circuit (Application Specific Integrated Circuit, 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. Embodiments of the Memory unit 912 include, but are not limited to, a subscriber identity module (Subscriber Identity Module, SIM), read-Only Memory (ROM), flash Memory, random-Access Memory (RAM), hard disk, and optical data storage. The communication unit 920 may be a transceiver and is configured to transmit and receive signals (e.g., messages or data packets) according to the processing result of the processor 900. In one embodiment, the communication unit 920 transmits and receives signals via at least one antenna 922 shown in fig. 9.

In one embodiment, the storage unit 910 and the program code 912 may be omitted, and the processor 900 may include a storage unit with stored program code.

Processor 900 may implement any of the steps of the exemplary embodiments on wireless terminal 90, for example, by executing program code 912.

The communication unit 920 may be a transceiver. The communication unit 920 may alternatively or additionally combine a transmission unit and a reception unit configured to transmit and receive signals to and from a wireless network node (e.g., a base station), respectively.

Fig. 10 relates to a schematic diagram of a wireless network node 100 according to an embodiment of the present disclosure. The wireless network node 100 may be a satellite, a Base Station (BS), a network entity, a mobility management entity (Mobility Management Entity, MME), a Serving Gateway (S-GW), a packet data network Gateway (Packet Data Network Gateway, P-GW), a radio access network RAN node, a Next Generation RAN (NG-RAN) node, gNB, eNB, gNB central unit (gNB-CU), a gNB distributed unit (gNB Distributed Unit, gNB-DU), a data network, a core network, or a radio network controller (Radio Network Controller, RNC), and is not limited herein. Further, the radio network node 100 may comprise (perform) at least one network function, such as an access and mobility management function AMF, a session management function SMF, a user location function UPF, a policy control function PCF, an application function AF, etc. The radio network node 100 may comprise a processor 1000, such as a microprocessor or ASIC, a storage unit 1010 and a communication unit 1020. The memory unit 1010 may be any data storage device that stores program code 1012 that is accessed and executed by the processor 1000. Examples of storage unit 1012 include, but are not limited to, a subscriber identity module, read only memory, flash memory, random access memory, hard disk, and optical data storage device. The communication unit 1020 may be a transceiver and is configured to transmit and receive signals (e.g., messages or data packets) according to the processing result of the processor 1000. In one example, communication unit 1020 transmits and receives signals via at least one antenna 1022 shown in fig. 10.

In one embodiment, the storage unit 1010 and the program code 1012 may be omitted. The processor 1000 may include a memory unit with stored program code.

Processor 1000 may implement any of the steps described in the exemplary embodiment on wireless network node 100, for example, by executing program code 1012.

The communication unit 1020 may be a transceiver. The communication unit 1020 may alternatively or additionally combine a transmitting unit and a receiving unit configured to transmit and receive signals to and from a wireless terminal (e.g., a wireless terminal), respectively. A user equipment or another radio network node).

While various embodiments of the present disclosure have been described above, it should be understood that they have been presented by way of example only, and not limitation. Likewise, the different diagrams may depict example architectures or configurations provided to enable those of ordinary skill in the art to understand the exemplary features and functions of the present disclosure. However, such persons will appreciate that the present disclosure is not limited to the example architectures or configurations shown, but may be implemented using a variety of alternative architectures and configurations. In addition, one or more features of one embodiment may be combined with one or more features of another embodiment described herein, as will be appreciated by those of ordinary skill in the art. Thus, the breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments.

It should also be understood that any reference to an element in this disclosure using names such as "first," "second," etc. generally does not limit the number or order of those elements. Rather, these designations may be used in this disclosure as a convenient means of distinguishing between two or more elements or instances of an element. Thus, reference to first and second elements does not mean that only two elements may be employed, or that the first element must somehow precede the second element.

In addition, those of skill in the art would understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, and symbols that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

Those of skill would further appreciate that any of the different illustrative logical blocks, units, processors, devices, circuits, methods, and functions described in connection with the aspects disclosed in this disclosure may be implemented with electronic hardware (e.g., digital implementations, analog implementations, or a combination of both), firmware, different forms of program or design code incorporating instructions (which may be referred to as "software" or "software units" in this disclosure for convenience), or any combination of these techniques.

To clearly illustrate this interchangeability of hardware, firmware, and software, various illustrative 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 such techniques depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation does not result in departing from the scope of the present disclosure. According to various embodiments, a processor, device, component, circuit, structure, machine, unit, or the like may be configured to perform one or more functions described in this disclosure. The term "configured to" or "configured for" as used in this disclosure with respect to a specified operation or function refers to a processor, device, component, circuit, structure, machine, unit, or the like that is physically constructed, programmed, and/or arranged to perform the specified operation or function.

Moreover, those of skill in the art will appreciate that the various illustrative logical blocks, units, devices, components, and circuits described in this disclosure may be implemented within or performed by an integrated circuit IC, which may comprise a general purpose processor, a digital signal processor DSP, an application specific integrated circuit ASIC, a field programmable gate array (Field Programmable Gate Array, FPGA), or other programmable logic device, or any combination thereof. Logic blocks, units, and circuits may also include antennas and/or transceivers to communicate with various components within the network or within the device. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, a combination of DSP cores or the above microprocessors, or any other suitable configuration for performing the functions described herein. If implemented in software, the functions may be stored on a computer-readable medium as one or more instructions or code. Thus, the steps of a method or algorithm of the present disclosure may be embodied as software stored on a computer readable medium.

Computer-readable media includes both computer storage media and communication media including any medium that can transfer a computer program or code from one place to another. A storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise random access memory, read only memory, charged erasable programmable read only memory, read only or other optical disk storage, magnetic disk storage or other magnetic storage devices, 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.

In this disclosure, the term "unit" as used in this disclosure refers to software, firmware, hardware, and any combination of these elements for performing the associated functions described in this disclosure. Furthermore, for purposes of discussion, the various units are described as discrete units; however, as will be apparent to one of ordinary skill in the art, two or more units may be combined to form a single unit that performs the associated functions in accordance with embodiments of the present disclosure.

Further, memory or other storage, as well as communication components, may be employed in embodiments of the present disclosure. It should be appreciated that for clarity, the above description has described embodiments of the 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 disclosure. For example, functions illustrated as being 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 only references to suitable means for providing the described functionality rather than indicative of a strict logical or physical structure or organization.

Various modifications to the implementations described in this disclosure will be readily apparent to those skilled in the art, and the generic principles defined in this disclosure may be applied to other implementations without departing from the scope of the disclosure. Thus, the present disclosure is not intended to be limited to the implementations 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. A wireless communication method for a first session management function, the method comprising:

receiving a context creation request for a protocol data unit session from an access and mobility management function, wherein the context creation request comprises first wireless terminal location information associated with a first wireless communication node,

sending a session context request associated with the protocol data unit session to a second session management function,

a session context associated with the protocol data unit session is received from the second session management function, wherein the session context includes second wireless terminal location information associated with a second wireless network node.

2. The wireless communication method according to claim 1, wherein the first wireless terminal position information and the second wireless terminal position information are the same,

wherein the session context further comprises tunnel information associated with an interface between the second radio network node and a first user plane function,

wherein the method further comprises at least one of:

the tunnel information for session using the protocol data unit, or

And sending the tunnel information to a second user plane function.

3. The wireless communication method of claim 2, wherein the tunnel information comprises at least one of an internet protocol address or a tunnel endpoint identifier of the protocol data unit session in the second wireless communication node.

4. The wireless communication method according to any one of claims 1 to 3, wherein the first wireless terminal position information and the second wireless terminal position information are the same,

wherein the method further comprises:

a request to modify the session context associated with the protocol data unit session is sent to the access and mobility management function.

5. The wireless communication method according to claim 1, wherein the first wireless terminal position information and the second wireless terminal position information are different,

wherein the method further comprises:

a request to establish the session context for the protocol data unit session is sent to the access and mobility management function.

6. The wireless communication method according to any one of claims 1 to 6, wherein the first wireless terminal position information and the second wireless terminal position information include at least one of: tracking area identity, new radio cell identity or global radio access network node identity.

7. A wireless communication method for a second session management function, the method comprising:

a session context request is received for a protocol data unit session from a first session management function,

a session context is sent to the first session management function, the session context comprising second wireless terminal location information associated with a second wireless network node.

8. The wireless communication method according to claim 7, further comprising:

the second wireless terminal location information is received from an access and mobility management function.

9. The wireless communication method according to claim 7 or 8, wherein the second wireless terminal position information includes at least one of: tracking area identity, new radio cell identity or global radio access network node identity.

10. The wireless communication method according to any of claims 7 to 9, wherein the session context further comprises tunnel information associated with an interface between the second wireless network node and a first user plane function.

11. The wireless communication method according to claim 10, further comprising:

The tunnel information is received from an access and mobility management function.

12. The wireless communication method of claim 11, wherein the tunnel information comprises at least one of an internet protocol address or a tunnel endpoint identifier of the protocol data unit session in the second wireless communication node.

13. A wireless communication method for a first session management function, the method comprising:

a context creation request for a protocol data unit session from an access and mobility management function is received, wherein the context creation request comprises an indication associated with validity of session information in a second radio network node of the protocol data unit session.

14. The wireless communication method according to claim 13, wherein the indication indicates that session information in the second wireless network node of the protocol data unit session is valid,

wherein the method further comprises:

a session context request associated with the protocol data unit session is sent to a second session management function, wherein the session context request includes an indication requesting tunnel information associated with an interface between the second radio network node and a first user plane function.

15. The wireless communication method according to claim 13 or 14, wherein the indication indicates that session information in the second wireless network node of the protocol data unit session is valid,

wherein the method further comprises:

receiving a session context for the protocol data unit session from a second session management function, wherein the session context comprises tunnel information associated with an interface between the second radio network node and a first user plane function,

wherein the method further comprises at least one of:

tunnel information for sessions using the protocol data unit, or

And sending the tunnel information to a second user plane function.

16. The wireless communication method according to claim 14 or 15, wherein the tunnel information comprises at least one of an internet protocol address or a tunnel endpoint identifier of the protocol data unit session in the second wireless communication node.

17. The wireless communication method according to any of the claims 13 to 16, wherein the indication indicates that session information in the second wireless network node of the protocol data unit session is valid,

Wherein the method further comprises:

18. The wireless communication method according to claim 13, wherein the indication indicates that session information in the second wireless network node of the protocol data unit session is not valid,

wherein the method further comprises:

a request to establish the session context associated with the protocol data unit session is sent to the access and mobility management function.

19. A wireless communication method for access and mobility management functions, the method comprising:

a context creation request for a protocol data unit session is sent to a first session management function, wherein the context creation request comprises an indication associated with validity of session information in a second radio network node of the protocol data unit session.

20. The wireless communication method according to claim 19, wherein the indication indicates that session information in the second wireless network node of the protocol data unit session is valid,

Wherein the method further comprises:

a request from the first session management function to modify the session context associated with the protocol data unit session is received.

21. The wireless communication method of claim 19, wherein the indication indicates that session information in the second wireless network node of the protocol data unit session is not valid,

wherein the method further comprises:

a request from the first session management function to establish the session context associated with the protocol data unit session is received.

22. A wireless device comprising a first session management function, the wireless device comprising:

a communication unit for receiving a context creation request for a protocol data unit session from an access and mobility management function, wherein the context creation request comprises first wireless terminal location information associated with a first wireless communication node,

23. The wireless device of claim 21, further comprising: a processor configured to perform the wireless communication method of any one of claims 2 to 6.

24. A wireless device comprising a second session management function, the wireless device comprising:

a communication unit for receiving a session context request associated with a protocol data unit session from a first session management function,

25. The wireless device of claim 24, further comprising: a processor configured to perform the wireless communication method of any one of claims 8 to 12.

26. A wireless device comprising a first session management function, the wireless device comprising:

a communication unit for receiving a context creation request for a protocol data unit session from an access and mobility management function, wherein the context creation request comprises an indication associated with validity of session information in a second radio network node of the protocol data unit session.

27. The wireless device of claim 25, further comprising: a processor configured to perform the wireless communication method of any one of claims 14 to 18.

28. A wireless device comprising access and mobility management functions, the wireless device comprising:

a communication unit for sending a context creation request for a protocol data unit session to a first session management function, wherein the context creation request comprises an indication associated with validity of session information in a second radio network node of the protocol data unit session.

29. The wireless device of claim 27, further comprising: a processor configured to perform the wireless communication method of claim 20 or 21.

30. A computer program product comprising computer readable program code stored thereon, characterized in that the code, when executed by a processor, causes the processor to implement the wireless communication method of any of claims 1 to 21.