Method of managing registration and session in a wireless communication system and apparatus performing the method

Abstract

The disclosure provides a method of performing access deregistration and an apparatus thereof, wherein a method of performing access deregistration by an access and mobility management function (AMF) includes: assigning a temporary identifier to a terminal during a registration procedure over a 3GPP access in a public land mobile network (PLMN), the assigned temporary identifier being reused in a registration procedure over a non-3GPP access for the terminal in the PLMN; after the terminal is registered over the 3GPP access and the non-3GPP access, determining to initiate a deregistration procedure over the 3GPP access to deregister the non-3GPP access for the terminal; based on the determination, sending a request to a session management function (SMF) for releasing protocol data unit (PDU) sessions, the request including a non-3GPP access PDU session ID, wherein all PDU sessions associated with the non-3GPP access are released based on the request.

Description

[0001] This application is a divisional application of patent application filed on March 16, 2018, with application number 201880017664.5 and entitled "Method for managing registration and sessions in a wireless communication system and apparatus for performing the method". Technical Field

[0002] This disclosure relates to a method for processing registration request messages for a terminal to register on a 5G network based on the access management function (AMF) that issues the temporary user ID when registering on a 5G network.

[0003] Furthermore, this disclosure relates to a method for processing a user's PDU session establishment request in the processing of a PDU session for service in a mobile communication system, taking into account whether the PDU session type supports Session Management Function (SMF).

[0004] Furthermore, this disclosure relates to a method for effectively managing terminal registration and session management when coverage loss occurs in a 5G network accessed via 3GPP access and non-3GPP access. Background Technology

[0005] To meet the increasing demand for wireless data traffic since the commercialization of 4G communication systems, efforts have been made to develop improved 5G or pre-5G communication systems. Therefore, 5G or pre-5G communication systems are also called super 4G network communication systems or post-LTE systems.

[0006] To achieve high data rates, 5G communication systems have been considered for implementation in ultra-high frequency (mmWave) bands (e.g., the 60 GHz band). To reduce path loss and increase transmission distance of radio waves in the mmWave band, beamforming, massive MIMO, full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive MIMO technologies for 5G communication systems have been discussed.

[0007] In addition, in 5G communication systems, in order to improve the system network, technologies have been developed for evolved small cells, advanced small cells, cloud radio access networks (cloud RAN), ultra-dense networks, device-to-device communication (D2D), wireless backhaul, mobile networks, cooperative communication, coordinated multipoint (CoMP), and receiver interference cancellation.

[0008] In addition, hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC) have been developed for advanced coding and modulation (ACM) systems, as well as filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) for advanced connectivity technologies.

[0009] On the other hand, the Internet, a human-centric network for generating and consuming information, is now evolving into the Internet of Things (IoT), where distributed entities such as things exchange and process information. The Internet of Everything (IoE), a combination of IoT technology connected to cloud servers and big data processing technology, has emerged. Since IoT implementation requires technological elements such as sensing technology, wired / wireless communication and network infrastructure, service interface technology, and security technology, sensor networks for machine-to-machine connections, machine-to-machine (M2M) communication, and machine-type communication (MTC) have recently been studied. Such an IoT environment can provide intelligent Internet of Things (IT) services, creating new value for human life by collecting and analyzing data generated between connected things. Through the integration and combination of existing information technology (IT) with various industries, IoT can be applied to a wide range of fields, including smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, healthcare, smart appliances, and advanced medical services.

[0010] Consistent with this, various attempts have been made to apply 5G communication systems to IoT networks. For example, technologies for sensor networks, machine-to-machine (M2M) communication, and MTC have been implemented using beamforming, MIMO, and array antennas, which correspond to 5G communication technologies. As a big data processing technology, the application of cloud radio access networks (cloud RAN) will be an example of the convergence between 5G and IoT technologies.

[0011] The above information is provided for background information purposes only to aid in understanding this disclosure. No determination or assertion is made as to whether any of the foregoing content may apply to prior art relating to this disclosure. Summary of the Invention

[0012] Technical issues

[0013] Various aspects of this disclosure are intended to at least address the aforementioned problems and / or disadvantages, and provide at least the following advantages. Therefore, one aspect of this disclosure is to provide an apparatus and method for a terminal that, when registering on a 5G network using a temporary user ID, can efficiently perform registration processing using the UE context of previous access via the temporary user ID and the current access context of a terminal accessing via another access. However, the operation of the AMF (Active Memory Frame) depends on whether the context indicated by the temporary user ID is the UE context of previous access or the current access context of a terminal accessing via another access, and one aspect of this disclosure provides a method for a terminal to process a registration request message for registration on a 5G network based on the state of the temporary user ID.

[0014] According to another aspect of this disclosure, in a mobile communication system, a terminal sends a PDU session establishment request to an AMF to initiate a PDU session for service purposes, and the AMF generates a PDU session by selecting and processing the PDU session establishment request message through an SMF.

[0015] Another aspect of the present invention provides a method for resuming SMF selection, such that if the SMF does not support the PDU session type requested by the terminal, for example, IP version, the SMF that supports the PDU session type requested by the terminal can handle the PDU session establishment request.

[0016] Another aspect of this disclosure provides a method for handling PDU sessions served by existing non-3GPP access (or non-3GPP access) services and processing the registration status of non-3GPP access when a terminal accesses a 5G network via 3GPP access (or non-3GPP access) and non-3GPP access, if the terminal leaves the coverage area of ​​the non-3GPP access. If the non-3GPP access PDU sessions continue or the registration status remains unchanged in the 5G network, unnecessary resources will be used; therefore, it is necessary to provide a method for effectively managing the registration and PDU sessions of non-3GPP access via 3GPP access.

[0017] Technical solution

[0018] According to one aspect of this disclosure, a method is provided for a user equipment (UE) to perform access deregistration. The method includes, when the UE is registered on both 3GPP access and non-3GPP access, sending a deregistration request message for deregistering the non-3GPP access to the Access and Mobility Management Function (AMF) via the 3GPP access; and receiving a deregistration acceptance message corresponding to the deregistration request message from the AMF via the 3GPP access.

[0019] Beneficial effects

[0020] According to one aspect of this disclosure, it is possible to efficiently process registration request messages sent by a terminal performing registration using a temporary user ID.

[0021] Furthermore, according to another aspect of this disclosure, through this disclosure, the terminal can successfully conduct a PDU session by selecting the SMF to adapt to the PDU session type for which the terminal intends to provide services, thereby enabling smooth use of service services.

[0022] Furthermore, according to another aspect of this disclosure, in cases where the terminal cannot use non-3GPP access, such as when the terminal is out of the coverage area of ​​non-3GPP access, terminal registration management and PDU session management can be effectively performed through 3GPP access. Therefore, it is possible to effectively manage resources in 5G networks through this disclosure.

[0023] Other aspects, advantages, and salient features of this disclosure will become apparent to those skilled in the art from the following detailed description of various embodiments disclosed in conjunction with the accompanying drawings. Attached Figure Description

[0024] The above and other aspects, features and advantages of certain embodiments of this disclosure will become more apparent from the following description taken in conjunction with the accompanying drawings, wherein:

[0025] Figure 1 This is a diagram illustrating an example of a cellular network structure using a common AMF when a terminal performs access via 3GPP access and non-3GPP access, according to an embodiment of the present disclosure, if the PLMN of the 3GPP access is the same as the PLMN of the N3IWF.

[0026] Figure 2 This diagram illustrates the processing of a registration request message routed based on a temporary user ID when the terminal uses a temporary user ID as routing information to be transmitted to the RAN or N3IWF during the registration process, according to an embodiment of this disclosure.

[0027] Figure 3 This is a diagram illustrating the process of the AMF processing the registration request message, which has received a registration request message including a temporary user ID, in the terminal registration process according to an embodiment of the present disclosure;

[0028] Figure 4 This is a diagram illustrating the process of the AMF processing the registration request message, which has received a registration request message including a temporary user ID, in the terminal registration process according to an embodiment of the present disclosure;

[0029] Figure 5 This is a diagram illustrating an example of a 5G network structure of a terminal according to an embodiment of the present disclosure;

[0030] Figure 6 This is a diagram illustrating the process of selecting an SMF and forwarding the PDU session establishment request to the selected SMF when a terminal sends a PDU session establishment request to a 5G network according to an embodiment of the present disclosure;

[0031] Figure 7 This is a diagram illustrating the process by which an AMF discovers a suitable SMF via NRF according to an embodiment of the present disclosure;

[0032] Figure 8 This is a diagram illustrating the process by which an AMF discovers a suitable SMF via NRF according to an embodiment of the present disclosure;

[0033] Figure 9 This is a diagram illustrating an example of a structure for a terminal to access a 5G network via 3GPP access and non-3GPP access according to an embodiment of the present disclosure;

[0034] Figure 10 This diagram illustrates the process by which a terminal releases its non-3GPP access PDU session or deregisters its non-3GPP access session locally if a terminal accessing a 5G network via 3GPP access or non-3GPP access cannot use non-3GPP access, according to an embodiment of this disclosure.

[0035] Figure 11 This diagram illustrates the process according to an embodiment of the present disclosure where, if a terminal accessing a 5G network via 3GPP access and non-3GPP access cannot use non-3GPP access, the terminal releases the non-3GPP access PDU session or deregisters non-3GPP access via 3GPP access.

[0036] Figure 12 This diagram illustrates the process, according to an embodiment of the present disclosure, where if a terminal accessing a 5G network via 3GPP access and non-3GPP access cannot use non-3GPP access, the terminal transfers its non-3GPP access PDU session to 3GPP access via 3GPP access.

[0037] Figure 13 This diagram illustrates the process according to an embodiment of the present disclosure: if the AMF identifies through the N3IWF that a terminal accessing the 5G network via 3GPP access and non-3GPP access cannot use non-3GPP access, then the non-3GPP access PDU session is released or the non-3GPP access is deregistered.

[0038] Figure 14This diagram illustrates the process according to an embodiment of the present disclosure: if the AMF identifies through the N3IWF that a terminal accessing the 5G network via 3GPP access and non-3GPP access cannot use non-3GPP access, then the non-3GPP access PDU session is released or the non-3GPP access is deregistered via 3GPP access.

[0039] Figure 15 This diagram illustrates the process of switching a PDU session from non-3GPP access to 3GPP access to 3GPP access if the AMF identifies through the N3IWF that a terminal accessing the 5G network via 3GPP access and non-3GPP access cannot use non-3GPP access, according to an embodiment of this disclosure.

[0040] Figure 16 This diagram illustrates the process of performing registration management and connection management when a terminal accessing a 5G network via 3GPP access and non-3GPP access, according to an embodiment of the present disclosure, identifies that it cannot use non-3GPP access.

[0041] Figure 17 This diagram illustrates the process of performing registration management and connection management according to an embodiment of the present disclosure if the AMF identifies through the N3IWF that a terminal accessing the 5G network via 3GPP access and non-3GPP access cannot use non-3GPP access.

[0042] Figure 18 This is a diagram illustrating the structure of a network entity according to an embodiment of the present disclosure; and

[0043] Figure 19 This is a diagram illustrating the structure of a terminal according to an embodiment of the present disclosure.

[0044] Throughout the accompanying drawings, it should be noted that the same reference numerals are used to depict the same or similar elements, features, and structures. Detailed Implementation

[0045] The following description, provided with reference to the accompanying drawings, is intended to aid in a full understanding of the various embodiments of this disclosure as defined by the claims and their equivalents. It includes various specific details to aid understanding, but these are to be considered exemplary only. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the various embodiments described herein without departing from the scope and spirit of this disclosure. Additionally, descriptions of well-known functions and structures may be omitted for clarity and brevity. In describing this disclosure, relevant well-known functions or configurations incorporated herein are not described in detail where it is determined that they would unnecessarily obscure the subject matter of this disclosure.

[0046] Furthermore, the terms described later are defined in consideration of their function in this disclosure, but may vary depending on the intent of the user and operator or custom. Therefore, they should be defined based on the entirety of the description in this disclosure.

[0047] The aspects and features of this disclosure, as well as methods for implementing these aspects and features, will become apparent from the embodiments described in detail with reference to the accompanying drawings. However, this disclosure is not limited to the embodiments disclosed below, but can be implemented in various forms. The content defined in the specification, such as detailed structures and elements, is merely specific detail provided to assist those skilled in the art in fully understanding this disclosure, and this disclosure is limited only by the scope of the appended claims. Throughout the description of this disclosure, the same reference numerals are used for the same elements in the various drawings.

[0048] First Embodiment

[0049] The operating principles of this disclosure will be described in detail below with reference to the accompanying drawings. In describing this disclosure below, detailed descriptions of relevant well-known functions or configurations included herein will be omitted if it is determined that such details obscure the subject matter of the disclosure with unnecessary detail. Furthermore, the terms described later are defined in consideration of their function in this disclosure, but may vary depending on the intent of the user and operator or custom. Therefore, they should be defined based on the entirety of the description of this disclosure.

[0050] In the following text, for ease of explanation, terms for identifying connected nodes, terms for referring to network entities, terms for referring to interfaces between network entities, and terms for referring to various identifying information, as used in the following description, are illustrated. Therefore, this disclosure is not limited to the terms described later, but other terms used to refer to subjects having the same technical meaning may be used.

[0051] In the following text, for ease of explanation, terms and headings defined in 5G system standards are used in this disclosure. However, this disclosure is not limited to these terms and headings, but can be applied equally to systems conforming to other standards. Furthermore, non-3GPP access includes access via WiFi, and can be applied equally to other access methods besides 5G access.

[0052] In the following text, if the terminal has successfully registered on the 5G network, the temporary UEID and temporary user ID used in the description and figures can be the same parameters with values ​​assigned to the terminal. In LTE systems, the temporary UEID and temporary user ID are temporary IDs with the same functionality as GUTI, and can be used interchangeably for convenience.

[0053] Figure 1This is a diagram illustrating an example of a cellular network structure using a common AMF when a terminal performs access via 3GPP access and non-3GPP access, according to an embodiment of the present disclosure, if the PLMN of the 3GPP access is the same as the PLMN of the N3IWF.

[0054] refer to Figure 1 When accessing the network via 3GPP, terminal (1-01) communicates with RAN (1-02), common AMF (1-03), and SMF (1-04, 1-05). When accessing the network via non-3GPP access (1-06), terminal 1-01 communicates with N3IWF (1-07), common AMF (1-03), and SMF (1-04, 1-05).

[0055] refer to Figure 1 If a terminal accesses the 5G core network (i.e., 5G RAN) via 3GPP access and simultaneously accesses the 5G core network via non-3GPP access, the N3IWF selected by the terminal can be in the same PLMN as the non-3GPP access PLMN, and in this case, the same public AMF can be selected.

[0056] If the terminal performs registration while a valid temporary user ID exists, it sends a registration request message including the temporary user ID. In this case, the AMF that has received the registration request message must distinguish whether the temporary user ID is one that the terminal has already received from a registered AMF via another access type (e.g., 3GPP access) or one that was received from an AMF in a previous registration process. That is, if the temporary user ID was received from an already registered AMF via another access type, the newly selected AMF performs registration by relocation to the AMF that was assigned the temporary user ID; otherwise, if the temporary user ID was received from an AMF in a previous registration process, the newly selected AMF continues the remaining registration process by retrieving the UE context from the AMF that was assigned the temporary user ID.

[0057] Here, N3IWF is a 5G core network device defined for smooth interlocking between non-3GPP access and the 5G core network, and is an entity used to forward NAS messages or data sent / received through non-3GPP access. N3IWF is also known as ngPDG.

[0058] Figure 2 This diagram illustrates the processing of a registration request message routed based on a temporary user ID when the terminal uses a temporary user ID as routing information to be transmitted to the RAN or N3IWF during the registration process, according to an embodiment of this disclosure.

[0059] When terminal 2-01 performs registration (2-11) with a previously assigned temporary user ID, it checks whether it has already registered through another access type and whether the temporary user ID is a temporary user ID managed by the AMF currently serving the terminal (2-12). For example, the terminal may be in a situation where it has already registered on a 5G network through 3GPP access and is using a temporary user ID issued by the registered AMF, or it may be in a situation where it has already registered on a 5G network through a non-3GPP access and is using a temporary user ID issued by the registered AMF.

[0060] In this scenario, when sending a registration request message via the AS layer, the terminal can include a temporary user ID as routing information in the registration request message. If it is determined that the temporary user ID was assigned by an AMF serving the terminal through another access type, the terminal adds an indication during registration via that other access to notify that the temporary user ID has been assigned to the terminal. Therefore, the RAN or N3IWF 2-02, having already received the routing information, routes the registration request message to the AMF that assigned the temporary user ID (2-16).

[0061] Figure 3 This diagram illustrates the process by which the AMF processes a registration request message, including a temporary user ID, in the terminal registration process according to an embodiment of this disclosure.

[0062] When terminal 3-01 performs registration (3-11) with a previously assigned temporary user ID, it checks whether it has already registered via another access type and whether the temporary user ID is a temporary user ID managed by the AMF currently serving the terminal (3-12). For example, the terminal may be in a situation where it has already registered on a 5G network via 3GPP access and is using a temporary user ID issued by the registered AMF, or it may be in a situation where it has already registered on a 5G network via non-3GPP access and is using a temporary user ID issued by the registered AMF.

[0063] In this scenario, the terminal can include a temporary user ID in the registration request message, allowing it to select the appropriate AMF when sending the registration request message. In this case, if it is determined that the temporary user ID was assigned by an AMF serving the terminal through another access type, the terminal adds an indication to the registration request message to notify that the temporary user ID was assigned to the terminal during registration through the other access. The AMF that has received the registration request message determines a scheme for processing the registration request, as in processing (3-15). For example, if it does not include an indication to notify that the temporary user ID was assigned to the terminal during registration through the other access, or if it includes a notification to notify that the temporary user ID was received during a previous registration, the AMF sends an information request message (3-16) to the AMF specified by the temporary user ID in order to retrieve the UE context from the AMF specified by the temporary user ID. In contrast, if it receives a registration request message including an indication to notify that the temporary user ID was assigned to the terminal during registration through the other access, the AMF identifies that the appended temporary user ID corresponds to the AMF currently serving the terminal and reroutes the registration request message to the AMF specified by the temporary user ID. That is, as in process (3-17a), the AMF (e.g., AMF1 3-03) can directly send the registration request message carried on the rerouted NAS message to the AMF specified by the temporary user ID (e.g., AMF2 3-04), or as in process (3-17b), it can reroute the registration request message carried on the rerouted NAS message to the RAN or N3IWF 3-02. In this case, the rerouted NAS message may include information about the AMF specified by the temporary user ID.

[0064] Figure 4 This diagram illustrates the process by which the AMF processes a registration request message, including a temporary user ID, in the terminal registration process according to an embodiment of this disclosure.

[0065] When terminal 4-01 performs registration (4-11) with a previously assigned temporary user ID, it sends a registration request message (4-13) including the temporary UE ID.

[0066] If the AMF that has received the registration request message does not have a UE context for the temporary UE ID, it sends an information request message to the AMF specified by the temporary UE ID in order to retrieve the UE context from the AMF specified by the temporary user ID (4-14). The information request message may include part or all of the address information of the RAN / N3IWF 4-02 that has already sent the registration request message, access information related to the access type, and N2 tunnel information with the AMF.

[0067] An AMF that has received an information request message (e.g., AMF2 4-04) determines whether to send the UE context for the temporary UE ID to the AMF that requested it or to reroute the registration request message to the AMF itself (4-15 and 4-16). That is, if it is determined that the AMF allocates and uses a temporary UE ID during registration via another access type (e.g., 3GPP access), it reroutes the registration request message sent to itself via a non-3GPP access to use the same AMF, regardless of the access type. Here, the method by which the AMF determines its allocation and use of the temporary UE ID during registration via another access type can be known from the access type information included in the registration request message, or if the registration type included in the registration request message is "initial registration," then registration via another access type may be known. Furthermore, registration via another access type can be known through the address information in RAN / N3IWF 4d-02 or access information related to the access type included in the information request, or through the synthesis and determination of some or all of the above schemes.

[0068] In contrast, when the AMF is changed through registration, such as when the AMF is changed based on the movement of the terminal or when the AMF that has been registered through existing non-3GPP access is changed to the AMF that is registered through 3GPP access, the AMF will send the UE context for the temporary UE ID to the AMF that has requested it (4-16).

[0069] Therefore, when the AMF is changed during the information response message sent in process (4-17), the AMF transfers the UE context to the new AMF that has requested it. In contrast, when rerouting the AMF to itself, the AMF can include a relocation request in the information response message to be sent. The new AMF, having received the relocation request, identifies the attached temporary user ID corresponding to the AMF currently serving the terminal and reroutes the registration request message to the AMF specified by the temporary user ID. That is, as in process (4-18a), the AMF can directly send the registration request message carried on the rerouting NAS message to the AMF specified by the temporary user ID, or as in process (4-18b), it can reroute the registration request message carried on the rerouting NAS message to the RAN or N3IWF 4-02 that sent the registration request message. In this case, the rerouting NAS message can include information about the AMF specified by the temporary user ID.

[0070] As another embodiment for rerouting the AMF back to itself, the AMF includes a relocation completion in the information response message, and the AMF itself acts as the serving AMF. In this case, using the address information of RAN / N3IWF 4-02 contained in the information request message or the N2 tunnel information with the AMF, the AMF sends an N2 message to RAN / N3IWF 4-02 to correct the N2 tunnel information between the AMF and RAN / N3IWF.

[0071] In the embodiments of this disclosure as described above, the constituent elements included in this disclosure are represented in either a singular or plural form. However, such singular or plural expressions are chosen to suit the circumstances presented for ease of interpretation, and therefore this disclosure is not limited to such singular or plural constituent elements. Even multiple constituent elements may be represented in a singular form, and even a single constituent element may be represented in a plural form.

[0072] On the other hand, although detailed embodiments of this disclosure have been described in the specification and drawings, it will be apparent that various modifications can be made within the scope of this disclosure. Therefore, the scope of this disclosure should not be limited to the embodiments described above, but should be defined by the appended claims and their equivalents.

[0073] Second Embodiment

[0074] The operating principles of this disclosure will be described in detail below with reference to the accompanying drawings. In describing this disclosure below, detailed descriptions of relevant well-known functions or configurations included herein will be omitted if it is determined that such details obscure the subject matter of the disclosure with unnecessary detail. Furthermore, the terms described later are defined in consideration of their function in this disclosure, but may vary depending on the intent or habit of the user and operator. Therefore, they should be defined based on the entirety of the description of this disclosure.

[0075] In the following text, for ease of explanation, terms for identifying connected nodes, terms for referring to network entities, terms for referring to interfaces between network entities, and terms for referring to various identifying information, as used in the following description, are illustrated. Therefore, this disclosure is not limited to the terms described later, but other terms used to refer to subjects having the same technical meaning may be used.

[0076] Figure 5 This is a diagram illustrating an example of a 5G network structure of a terminal according to an embodiment of the present disclosure.

[0077] refer to Figure 5 The terminal registers on the 5G core network by accessing the AMF via (R)AN. If the terminal sends a PDU session establishment request to the AMF via (R)AN to receive service, the AMF selects a suitable SMF. In this process, to discover the SMF, the AMF requests the NRF to discover the SMF, and in response, the NRF transmits the address information of the discovered SMF to the AMF so that the AMF can select a suitable SMF.

[0078] If a PDU session establishment request is transmitted to the selected SMF, the PDU session generation process is executed to allocate an address to the terminal according to the PDU session establishment request, select a UPF as the G / W for external transmission / reception services, and allocate resources.

[0079] Figure 6 This is a diagram illustrating the process by which a terminal, when sending a PDU session establishment request to a 5G network, considers the PDU session type selection SMF and forwards the PDU session establishment request to the selected SMF, according to an embodiment of the present disclosure.

[0080] Terminal 6-01 generates a PDU session establishment request and sends it to AMF (6-10). The PDU session establishment request message includes part or all of the DNN or S-NSSAI information requested by the terminal, the PDU session type, and the PDU session ID assigned by the terminal. The PDU session type can be IPv4, IPv6, Ethernet, or unstructured PDU session type.

[0081] An AMF that has received a PDU session establishment request from UE 6-01 (e.g., AMF 6-02) may send an SMF discovery to NRF 6-03, taking into account DNN information or S-NSSAI information (6-11), and in response, it receives a discovery response (6-12) including the address information of the discovered SMF. Based on the information of the received SMF, the AMF performs SMF selection (6-13).

[0082] Specifically, as an embodiment of the AMF and NRF operation scheme in the above processes (6-11, 6-12, and 6-13), if the AMF can also receive PDU session establishment requests and analyze PDU session types in addition to the DNN and S-NSSAI information requested by the terminal, then during the SMF discovery request in operation 6-11, in addition to the DNN and S-NSSAI information, the AMF can also request SMF discovery by including the PDU session type. In response, the NRF sends a discovery response including the address information or ID information of the SMF that meets the PDU session type and the DNN and S-NSSAI information requested in operation 6-11 (6-12), and the AMF selects the appropriate one of the received SMFs (6-13).

[0083] As another embodiment of the AMF and NRF operation scheme in the above processes (6-11, 6-12, and 6-13), if the AMF can also receive PDU session establishment requests and analyze PDU session types in addition to the DNN and S-NSSAI information requested by the terminal, then the AMF can request SMF discovery during operation 6-11 by including DNN and S-NSSAI information. In response, the NRF sends a discovery response (6-12) including the address or ID information of the SMF that satisfies the DNN and S-NSSAI information requested in operation 6-11 (6-12), the payload information of the SMF, and information about the PDU session types supported by the SMF, and the AMF selects a suitable SMF among the received SMFs that support the PDU session types requested by the terminal (6-13).

[0084] As another embodiment of the AMF and NRF operation scheme in the above processes (6-11, 6-12, and 6-13), although the AMF can receive PDU session establishment requests and analyze the DNN and S-NSSAI information requested by the terminal, it cannot analyze the PDU session type requested by the terminal. The AMF can request SMF discovery during operation 6-11 by including DNN and S-NSSAI information. In response, the NRF sends a discovery response (6-12) including the address or ID information of the SMF that satisfies the DNN and S-NSSAI information requested in operation 6-11, the SMF's payload information, and information about the PDU session types supported by the SMF, and the AMF selects a suitable one from the received SMFs. However, in this case, since the AMF does not know the information about the PDU session type requested by the terminal, it selects the SMF (6-13) without considering the PDU session type. However, the AMF can store the SMF information and the information about the PDU session type for later use in selecting the SMF.

[0085] On the other hand, after selecting the SMF through processing (6-13), the AMF will send the PDU session establishment request message, which includes the SM request message, to the selected SMF (6-14).

[0086] The SMF that has received the request message checks whether it supports the PDU session establishment request requested by the terminal. Specifically, the SMF (e.g., SMF1 6-04) checks whether it supports the PDU session type requested by the terminal (6-15). If the SMF supports the PDU session type, it continues to perform the remaining PDU session establishment processing, such as authentication / authorization of the PDU session establishment request, UPF allocation, and resource reservation, without reselecting an SMF in operation 6-16 (6-22).

[0087] In contrast, if the selected SMF does not support the PDU session type requested by the terminal, it reselects an SMF according to the process (6-16). That is, when sending an ACK for the SM request, the SMF may include a reason to indicate that the SM request has not been properly processed and to redirect the PDU session establishment request message by selecting another SMF that supports the PDU session type requested by the terminal, and may also include information about the PDU session type requested by the terminal along with the reason.

[0088] If an ACK for the SM request is received, the SMF can use the SMF address or ID information obtained in operations 6-11 and 6-12, along with information about the PDU session types supported by the SMF, to select a suitable SMF to support the PDU session type requested by the terminal. Alternatively, it can use the NRF to obtain information about the SMF again. That is, the SMF discovery request message is sent to the NRF (6-18), and in response, the SMF obtains its address or ID information and information about the PDU session types supported by the SMF (6-19). Based on the obtained information, a suitable SMF is selected to support the PDU session type requested by the terminal (6-20).

[0089] Specifically, as an embodiment of the AMF and NRF operation scheme in the above processes (6-18, 6-19, and 6-20), considering the PDU session type requested by the terminal and obtained through operation 6-17, during the SMF discovery request in operation 6-11, in addition to DNN and S-NSSAI information, the AMF can also request SMF discovery including the PDU session type. In response, the NRF sends a discovery response (6-19) including the address information or ID information of the SMF, or the payload information of the SMF that meets the PDU session type requested in operation 6-18, as well as DNN and S-NSSAI information, and the AMF selects the appropriate one among the received SMFs (6-20).

[0090] As another embodiment of the AMF and NRF operation scheme in the above processes (6-18, 6-19, and 6-20), the AMF may request SMF discovery including DNN and S-NSSAI information during the SMF discovery request in operation 6-11. In response, the NRF sends a discovery response (6-19) including the address information or ID information of the SMF, or the payload information of the SMF that satisfies the DNN and S-NSSAI information requested in operation 6-18, and information about the PDU session type supported by the SMF, and the AMF selects a suitable SMF among the received SMFs that support the PDU session type requested by the terminal (6-20).

[0091] On the other hand, after selecting an SMF through processing (6-20), the AMF transmits a PDU session establishment request message, which includes the SM request message, to the selected SMF (6-21). The SMF that has received the PDU session establishment request continues to perform the remaining PDU session establishment processing, such as authentication / authorization of the PDU session establishment request, UPF allocation, and resource reservation (6-22).

[0092] Figure 7 This is a diagram illustrating the process by which an AMF discovers a suitable SMF via NRF according to an embodiment of the present disclosure.

[0093] Figure 7 This is an example of the AMF according to this disclosure. Figure 6 Operations 6-11 and 6-12 or operations 6-18 and 6-19 are used to find the appropriate SMF processing diagram through NRF.

[0094] The AMF can receive PDU session establishment requests, and in order to select an SMF, the AMF can request SMF discovery, including DNN and S-NSSAI information and UE location information, during Operation 7-04 when requesting SMF discovery. In response, the NRF sends a discovery response (7-05) including the SMF's address or ID information, SMF payload information, and PDU session type information supported by the SMF, which satisfies the information requested in Operation 7-05.

[0095] If the PDU session type information requested by the terminal is obtained, the AMF will select the SMF that supports the PDU session type requested by the terminal from the discovered SMFs.

[0096] Figure 8 This is a diagram illustrating the process by which an AMF discovers a suitable SMF via NRF according to an embodiment of the present disclosure.

[0097] Figure 8 This is an example of AMF 8-01 according to this disclosure. Figure 6 Operations 6-11 and 6-12 or operations 6-18 and 6-19 are used to find the appropriate SMF processing diagram via NRF 8-02.

[0098] AMF 8-01 can receive PDU session establishment requests, and in order to select an SMF, AMF 8-01 can request SMF discovery during Operation 8-04, which includes DNN and S-NSSAI information, UE location information, and PDU session type information requested by the terminal. In response, NRF 8-02 sends a discovery response (8-05) including the address or ID information of the SMF that satisfies the information requested in Operation 8-05, and the payload information of the SMF.

[0099] AMF selects the SMF from the discovered SMFs.

[0100] In the embodiments of this disclosure as described above, the constituent elements included in this disclosure are represented in either a singular or plural form. However, such singular or plural expressions are chosen to suit the circumstances presented for ease of interpretation, and therefore this disclosure is not limited to such singular or plural constituent elements. Even multiple constituent elements may be represented in a singular form, and even a single constituent element may be represented in a plural form.

[0101] On the other hand, although detailed embodiments of this disclosure have been described in the specification and drawings, it will be apparent that various modifications can be made within the scope of this disclosure. Therefore, the scope of this disclosure should not be limited to the embodiments described above, but should be defined by the appended claims and their equivalents.

[0102] Third Embodiment

[0103] The operating principles of this disclosure will be described in detail below with reference to the accompanying drawings. In describing this disclosure below, detailed descriptions of relevant well-known functions or configurations included herein will be omitted if it is determined that such details obscure the subject matter of the disclosure with unnecessary detail. Furthermore, the terms described later are defined in consideration of their function in this disclosure, but may vary depending on the intent of the user and operator or custom. Therefore, they should be defined based on the entirety of the description of this disclosure.

[0104] In the following text, for ease of explanation, terms for identifying connected nodes, terms for referring to network entities, terms for referring to interfaces between network entities, and terms for referring to various identifying information, as used in the following description, are illustrated. Therefore, this disclosure is not limited to the terms described later, but other terms used to refer to subjects having the same technical meaning may be used.

[0105] In the following text, for ease of explanation, terms and headings defined in 5G system standards are used in this disclosure. However, this disclosure is not limited to these terms and headings, but can be applied equally to systems conforming to other standards. Furthermore, non-3GPP access includes access via WiFi, and can be applied equally to other access methods besides 5G access.

[0106] Figure 9 An example of a structure for a terminal to access a 5G network via a non-3GPP access method according to an embodiment of this disclosure is shown. Specifically, Figure 9 The architecture for using the common AMF is also shown, where the terminal accesses via 3GPP access and non-3GPP access.

[0107] refer to Figure 9 When terminal 9-01 accesses the network via 3GPP access, it communicates through RAN 9-02, AMF 9-03, SMF 9-04, 9-06, UPF 9-05, and 9-09. When terminal 9-01 accesses the network via non-3GPP access 9-07, it communicates through N3IWF 9-08, AMF 9-03, SMF 9-06, and UPF (9-09).

[0108] refer to Figure 9 If a terminal accesses the 5G core network (5G RAN) via 3GPP access and simultaneously accesses the 5G core network via non-3GPP access, then the common AMF is selected. The terminal accesses the 5G core network via both 3GPP and non-3GPP access, and the AMF manages registration separately for both 3GPP and non-3GPP access.

[0109] Here, N3IWF is a 5G core network device defined for smooth interlocking between non-3GPP access and the 5G core network, and is the entity used to forward NAS messages or data sent / received through non-3GPP access. N3IWF is also known as ngPDG. SMF is the entity used to manage sessions and assign IP addresses to terminals, and UPF is used to forward user data under the control of SMF.

[0110] According to embodiments of this disclosure, when the AMF manages registration via non-3GPP access, the method for managing registration may vary depending on whether the corresponding terminal has registered via 3GPP access.

[0111] For example, if a terminal cannot use 5G network services through non-3GPP access, such as if the terminal is out of the coverage area of ​​non-3GPP access, or if the non-3GPP access module is turned off, then in the state where the corresponding terminal has registered through 3GPP access and has registered through non-3GPP access, the terminal and the 5G core network can effectively manage resources by processing PDU sessions served by non-3GPP access through 3GPP access, or by performing deregistration of non-3GPP access.

[0112] Figure 10 The present disclosure illustrates a process where, if a terminal accessing a 5G network via 3GPP access and non-3GPP access cannot use non-3GPP access, the terminal locally releases the non-3GPP access PDU session or locally deregisters the non-3GPP access.

[0113] Terminal 10-01, which successfully registered on the 5G network via 3GPP access and non-3GPP access, uses a PDU session (10-11) generated via non-3GPP access.

[0114] In this situation, if the terminal becomes unable to perform non-3GPP access, such as if the terminal leaves the coverage area of ​​non-3GPP access or if the non-3GPP access module is turned off, the terminal operates a timer and waits until non-3GPP access can be used again for a predetermined time (10-12).

[0115] If it is still not possible to use non-3GPP access by the timer expires, such as if the terminal returns to the coverage area of ​​non-3GPP access or the non-3GPP access module is turned on again, the terminal can release the PDU session used through non-3GPP access locally, or perform non-3GPP access deregistration locally according to the existing configuration or user input (10-13).

[0116] On the other hand, since the terminal has already registered for 3GPP access, it sends a registration request message to the AMF via 3GPP access in order to update the registration based on the terminal's mobility or periodicity (10-14). In this case, the registration request message may include items for PDU sessions or deregistration situations for non-3GPP access.

[0117] For example, the terminal may include an indication to notify the terminal that the PDU session ID used for non-3GPP access has been released, or an indication to notify the terminal that the non-3GPP access has been deregistered.

[0118] The AMF that has received the registration request message including the above instructions will synchronize the status of the corresponding PDU session in the 5G core network and the registration status of non-3GPP access with the terminal according to the above instructions (10-15).

[0119] For example, if the instruction indicates that the terminal has released the PDU session ID used for non-3GPP access, the AMF sends a PDU session release request to the SMF that manages the PDU session corresponding to the PDU session ID, so that the SMF and UPF release the PDU session corresponding to the PDU session ID, and the AMF notifies the N3IWF to release the tunnel between the N3IWF and the UPF, so as to erase the PDU session used for non-3GPP access from the 5G network.

[0120] Furthermore, if the indicated terminal has released the PDU session ID used through non-3GPP access, the AMF releases all PDU sessions used through non-3GPP access through the PDU session release process and sets the registration status of non-3GPP access to deregister.

[0121] The processing result can be included in the registration acceptance message to be sent to the terminal.

[0122] In other words, the terminal may include an indication for notifying that a PDU session ID that has been released by the terminal has been notified to be released, or an indication for notifying that the 5G core network has been deregistered for non-3GPP access (10-16).

[0123] Figure 11The present disclosure illustrates a process according to an embodiment of the present disclosure whereby a terminal accessing a 5G network via 3GPP access or non-3GPP access cannot use non-3GPP access, and the terminal releases the non-3GPP access PDU session or deregisters non-3GPP access via 3GPP access.

[0124] Terminal 11-01, which successfully registered on the 5G network via 3GPP access and non-3GPP access, uses a PDU session (11-11) generated via non-3GPP access.

[0125] In this situation, if the terminal becomes unable to perform non-3GPP access, such as if the terminal leaves the coverage area of ​​non-3GPP access or if the non-3GPP access module is turned off, the terminal operates a timer and waits until non-3GPP access can be used again for a predetermined time (11-12).

[0126] If it is still not possible to use non-3GPP access by the timer expires, such as if the terminal returns to the coverage area of ​​non-3GPP access or the non-3GPP access module is turned on again, the terminal can release the PDU session used through non-3GPP access, or trigger the deregistration of non-3GPP access based on the existing configuration or user input (11-13).

[0127] Therefore, when performing operations 11-14, especially when the terminal releases a PDU session used via non-3GPP access, it transmits a PDU session release request message 11-15 to the AMF via 3GPP access for the corresponding PDU session. The PDU session release message includes the corresponding PDU session ID.

[0128] The AMF that has received the message sends a PDU session release request to the SMF that manages the PDU session corresponding to the PDU session ID, so that the SMF and UPF release the PDU session corresponding to the PDU session ID, and notifies the N3IWF through the AMF to release the tunnel between the N3IWF and the UPF, so as to erase the PDU session used for non-3GPP access from the 5G network (11-18).

[0129] In contrast, if the terminal performs deregistration for non-3GPP access, it transmits a deregistration request message (11-16) for non-3GPP access to the AMF via the 3GPP access. The AMF requests the corresponding SMF to release all PDU sessions used through non-3GPP access (11-17). Furthermore, the requested SMF performs PDU session release (11-18). Additionally, after deregistration for non-3GPP access, the SMF sends a deregistration acceptance (non-3GPP access) message (11-19) to the terminal via the 3GPP access.

[0130] Figure 12 The present disclosure illustrates a process in which a terminal, if accessing a 5G network via 3GPP access and non-3GPP access is not able to use non-3GPP access, transfers the PDU session of the non-3GPP access to 3GPP access via 3GPP access, according to an embodiment of the present disclosure.

[0131] Terminal 12-01, which successfully registered on the 5G network via 3GPP access and non-3GPP access, uses a PDU session (12-11) generated via non-3GPP access.

[0132] In this situation, if the terminal becomes unable to perform non-3GPP access, such as if the terminal leaves the coverage area of ​​non-3GPP access or if the non-3GPP access module is turned off, the terminal operates a timer and waits until non-3GPP access can be used again for a predetermined time (12-12).

[0133] If it is still not possible to use non-3GPP access by the timer expires, such as if the terminal returns to the coverage area of ​​non-3GPP access or turns on the non-3GPP access module again, the terminal can trigger the transfer of the PDU session used through non-3GPP access to 3GPP access based on the existing configuration or user input (12-13).

[0134] Therefore, the terminal transmits PDU session establishment request messages 12-14 to the AMF via 3GPP access for the corresponding PDU session, so as to transfer PDU sessions used through non-3GPP access. The PDU session establishment request message includes the corresponding PDU session ID and an indication indicating that the PDU session has been transferred to 3GPP access.

[0135] Upon receiving the message, the AMF sends a PDU session establishment request to the SMF managing the PDU session corresponding to the PDU session ID. The SMF then establishes a tunnel for the PDU session via the UPF and the 5G RAN (i.e., the 5G base station), erasing the existing tunnel between the UPF and the N3IWF. Therefore, the PDU is transferred to 3GPP access instead of non-3GPP access (12-15), and the UPF serves the PDU session via the AMF to erase PDU sessions using non-3GPP access from the 5G network (11-18).

[0136] Figure 13 The present disclosure illustrates a process according to an embodiment of the present disclosure whereby if the AMF, through the N3IWF, identifies that a terminal accessing the 5G network via 3GPP access and non-3GPP access cannot use non-3GPP access, the process involves releasing the non-3GPP access PDU session or deregistering the non-3GPP access.

[0137] Terminal 13-01, which successfully registered on the 5G network via 3GPP access and non-3GPP access, uses a PDU session (13-11) generated via non-3GPP access.

[0138] In this situation, if the terminal becomes unable to perform non-3GPP access, such as if the terminal leaves the coverage area of ​​non-3GPP access, or if the non-3GPP access module is turned off, and N3IWF 13-02 notifies the AMF that non-3GPP access has become impossible, the AMF operates a timer and waits until non-3GPP access can be used again for a predetermined time (13-12).

[0139] If non-3GPP access remains impossible until the timer expires, the AMF can release PDU sessions used via non-3GPP access based on the operator's configuration or policy. In this case, the AMF can send a PDU session release request to the SMF managing the PDU sessions used via non-3GPP access, causing the SMF and UPF to release the PDU session corresponding to the PDU session ID. Furthermore, the AMF can notify the N3IWF to release the tunnel between the N3IWF and UPF, thereby erasing the PDU sessions used via non-3GPP access from the 5G network.

[0140] In contrast, if the AMF performs deregistration on a non-3GPP access based on the operator's configuration or policy, it requests the corresponding SMF to release all PDU sessions used through the non-3GPP access. The requested SMF releases the PDU sessions and switches the non-3GPP access to the deregistered state (13-16).

[0141] On the other hand, since the terminal has already registered for 3GPP access, it sends a registration request message to the AMF via 3GPP access to update the registration based on the terminal's mobility or periodically (13-14). In response, the AMF sends a registration acceptance message to the terminal, which includes an indication to notify that the PDU session for non-3GPP access will be released or an indication to notify that the 5G core network has performed deregistration for non-3GPP access (10-15). Based on the received indication, the terminal can synchronize with the 5G core network, such as releasing the PDU session for non-3GPP access locally or performing deregistration for non-3GPP access locally.

[0142] Figure 14 The present disclosure illustrates a process according to an embodiment of the present disclosure whereby, if the AMF identifies via the N3IWF that a terminal accessing the 5G network via 3GPP access and non-3GPP access cannot use non-3GPP access, the process involves releasing the non-3GPP access PDU session or deregistering the non-3GPP access via 3GPP access.

[0143] Terminal 14-01, which successfully registered on the 5G network via 3GPP access and non-3GPP access, uses a PDU session (14-11) generated via non-3GPP access.

[0144] In this situation, if the terminal becomes unable to perform non-3GPP access, such as if the terminal leaves the coverage area of ​​non-3GPP access, or if the non-3GPP access module is turned off, and N3IWF 14-02 notifies the AMF that non-3GPP access has become impossible, the AMF operates a timer and waits until non-3GPP access can be used again for a predetermined time (14-12).

[0145] If non-3GPP access remains impossible until the timer expires, the AMF can release PDU sessions used via non-3GPP access based on the operator's configuration or policy. In this case, the AMF sends a PDU session release request (14-14) to the SMF that manages the PDU sessions used via non-3GPP access, and the SMF executes the PDU session release process initiated by the NW to release the PDU session corresponding to the PDU session ID, and notifies the N3IWF to release the tunnel between the N3IWF and the UPF, so as to erase the PDU sessions used via non-3GPP access from the 5G network (14-15).

[0146] In contrast, if the AMF performs deregistration for non-3GPP access based on the operator's configuration or policy, it sends a PDU session release request (14-14) to the SMF managing PDU sessions used through non-3GPP access. The SMF then executes the NW-initiated PDU session release process to release the PDU session corresponding to the PDU session ID and notifies the N3IWF to release the tunnel between the N3IWF and the UPF, thereby erasing the PDU sessions used through non-3GPP access from the 5G network (14-15). Furthermore, to deregister non-3GPP access, the AMF sends an NW-triggered deregistration request (non-3GPP access) to the terminal (14-16).

[0147] Figure 15 The present disclosure illustrates a process according to an embodiment of the present disclosure whereby if the AMF identifies, via the N3IWF, that a terminal accessing the 5G network via 3GPP access and non-3GPP access cannot use non-3GPP access, the process involves switching the non-3GPP access PDU session to 3GPP access.

[0148] Terminal 15-01, which successfully registered on the 5G network via 3GPP access and non-3GPP access, uses a PDU session (15-11) generated via non-3GPP access.

[0149] In this situation, if the terminal becomes unable to perform non-3GPP access, such as if the terminal leaves the coverage area of ​​non-3GPP access, or if the non-3GPP access module is turned off, and N3IWF 15-02 notifies the AMF that non-3GPP access has become impossible, the AMF operates a timer and waits until non-3GPP access can be used again for a predetermined time (15-12).

[0150] If non-3GPP access remains impossible until the timer expires, the AMF can release PDU sessions used via non-3GPP access based on the operator's configuration or policy. In this case, the AMF can send a PDU session release request (15-13) to the SMF managing the PDU sessions used via non-3GPP access, and can also send a PDU session modification request to the terminal to switch the PDU session corresponding to the PDU session ID to 3GPP access. The request message includes the PDU session ID and an indication to switch to 3GPP access (15-14).

[0151] The terminal that has received the request will transmit a PDU session establishment request message 15-15 to the AMF via 3GPP access for the corresponding PDU session, so as to transfer the PDU session used through non-3GPP access to 3GPP access. The PDU session establishment request message includes the corresponding PDU session ID and an indication of the situation in which the PDU session is transferred to 3GPP access.

[0152] Upon receiving the message, the AMF sends a PDU session establishment request message to the SMF managing the PDU session corresponding to the PDU session ID. The SMF then establishes a tunnel for the PDU session through the UPF via the 5G RAN (i.e., the 5G base station) and erases the existing tunnel between the UPF and the N3IWF. Therefore, the PDU session is transferred, enabling service of the PDU session via 3GPP access instead of non-3GPP access (15-16).

[0153] Figure 16 The present disclosure illustrates a process for performing registration and connection management when a terminal accessing a 5G network via 3GPP access and non-3GPP access is identified as being unable to use non-3GPP access, according to an embodiment of the present disclosure.

[0154] If a terminal that has successfully registered on the 5G network via 3GPP access and non-3GPP access uses a PDU session generated via non-3GPP access, it will become unable to perform non-3GPP access, such as if the terminal leaves the coverage area of ​​non-3GPP access, or if the non-3GPP access module is turned off. In this case, it will operate a timer and wait until non-3GPP access can be used again for a predetermined time (16-01).

[0155] If, under conditions where non-3GPP access is impossible until the timer expires, the terminal is configured to switch a non-3GPP access PDU session to 3GPP access, or if the user chooses to perform this operation (16-02), the terminal initiates the process of transferring the non-3GPP access PDU session to 3GPP access (16-03). To do this, the terminal sends a PDU session establishment request message to the SMF via the AMF to switch the PDU session for use via 3GPP access. The PDU session establishment request message includes the PDU session ID of the PDU session to be transferred and an indication to notify of the switch to 3GPP access.

[0156] On the other hand, if the terminal is set to release the PDU session for non-3GPP access, or if the user chooses to do so, when it is impossible to use non-3GPP access until the timer expires (16-05), the terminal locally releases the PDU session for non-3GPP access, or locally deregisters the non-3GPP access according to this setting (16-06). Thereafter, when the terminal performs a registration update via 3GPP access, the registration request message may include an indication to notify that the PDU session for non-3GPP access will be released, or an indication to notify that local deregistration for non-3GPP access has been performed (16-07).

[0157] On the other hand, the terminal can send a PDU session release request to release a non-3GPP access PDU session, or according to this setting, it can send a UE request for deregistration (non-3GPP access) message to the 5G core network to deregister non-3GPP access (16-08).

[0158] Figure 17 The present disclosure illustrates that if the AMF identifies through the N3IWF that a terminal accessing the 5G network via 3GPP access and non-3GPP access cannot use non-3GPP access, then registration management and connection management processes are performed according to an embodiment of the present disclosure.

[0159] If a terminal that has successfully registered on the 5G network via 3GPP access and non-3GPP access becomes unable to perform non-3GPP access, for example, if the terminal leaves the coverage area of ​​non-3GPP access, or if the non-3GPP access module is turned off, and the N3IWF notifies the AMF that non-3GPP access has become impossible, then the AMF operates a timer and waits until non-3GPP access can be used again for a predetermined time (17-01).

[0160] If, under the condition that it is impossible to use non-3GPP access until the timer expires, the system is set to switch the non-3GPP access PDU session to 3GPP access, or the service provider's policy chooses to do so (17-02), then the AMF requests the SMF to perform the process of transferring the non-3GPP access PDU session to 3GPP access (17-03). To this end, the SMF sends a PDU session modification request to the terminal to switch the PDU session to 3GPP access (17-04).

[0161] The terminal sends a PDU session establishment request message to the SMF via the AMF to switch PDU sessions via 3GPP access. For this purpose, the PDU session establishment request message includes the PDU session ID of the PDU session to be transferred and an indication to notify of the switch to 3GPP access.

[0162] On the other hand, if the system is set to release the non-3GPP access PDU session when it is impossible to use non-3GPP access until the timer expires, or if the service provider's policy chooses to perform this operation in the 5G core network (17-05), then the AMF releases the non-3GPP access PDU session through the SMF, or performs local deregistration of the non-3GPP access according to the settings (17-06). Subsequently, when the terminal performs a registration update via 3GPP access, the registration acceptance message may include an indication to notify that the non-3GPP access PDU session will be released, or an indication to notify that local deregistration has been performed for the non-3GPP access (17-07).

[0163] On the other hand, the AMF can send a PDU session release request to the terminal through 3GPP access in order to release the PDU session of non-3GPP access through the SMF, or according to the above settings, send a deregistration request (non-3GPP access) message of NW request to the terminal through 3GPP access to cancel the registration of non-3GPP access (17-08).

[0164] Figure 18 This is a diagram illustrating the structure of a network entity according to an embodiment of the present disclosure. The network entity can be referenced... Figures 1-17 Each configuration of the network shown. For example, refer to Figure 1 Network entities can be base stations (RAN), public AMF, SMF, N3IWF, etc. For example, refer to Figure 5 Network entities can be RAN, AMF, NRF, SMF, UPF, etc. For example, refer to Figure 9 Network entities can be RAN, AMF, NRF, SMF, UPF, N3IWF, etc.

[0165] refer to Figure 18The network entity may include a transmitting / receiving unit (or transceiver) 1810, a control unit (or controller or at least one processor) 1820, and a storage unit 1830 (e.g., a memory). In this disclosure, the control unit may be defined as a circuit or an application-specific integrated circuit or at least one processor.

[0166] The transmit / receive unit 1810 can transmit signals to or receive signals from a terminal or another network entity. According to embodiments of this disclosure, the control unit 1820 can control the overall operation of a network entity. For example, the control unit 1820 can control the signal flow between each block to perform operations according to the flowchart described above.

[0167] The storage unit 1830 can store at least one of the information sent and received by the sending / receiving unit 1810 and the information generated by the control unit 1820.

[0168] Figure 19 This is a diagram illustrating the structure of a terminal according to an embodiment of the present disclosure.

[0169] refer to Figure 19 The terminal may include a transmitting / receiving unit (or transceiver) 1910, a control unit (or controller or at least one processor) 1920, and a storage unit 1930 (e.g., a memory). In this disclosure, the control unit may be defined as a circuit or an application-specific integrated circuit or at least one processor.

[0170] The transmitting / receiving unit 1910 can transmit and receive signals with other network entities. The transmitting / receiving unit 1910 can receive system information from, for example, a base station, and can receive synchronization signals or reference signals.

[0171] The control unit 1920 can control the overall operation of the terminal according to embodiments of the present disclosure. For example, the control unit 1920 can control the signal flow between each block to perform operations according to the flowchart above.

[0172] The storage unit 1930 can store at least one of the information sent and received by the sending / receiving unit 1910 and the information generated by the control unit 1920.

[0173] In the embodiments of this disclosure as described above, the constituent elements included in this disclosure are represented in either a singular or plural form. However, such singular or plural expressions are chosen to suit the circumstances presented for ease of interpretation, and therefore this disclosure is not limited to such singular or plural constituent elements. Even multiple constituent elements may be represented in a singular form, and even a single constituent element may be represented in a plural form.

[0174] Although detailed embodiments of the present disclosure have been described in the specification and drawings, it will be apparent that various modifications can be made within the scope of this disclosure. Therefore, the scope of this disclosure should not be limited to the embodiments described above, but should be defined by the appended claims and their equivalents.

[0175] Although this disclosure has been shown and described with reference to various embodiments thereof, those skilled in the art will understand that various changes in form and detail may be made therein without departing from the spirit and scope of this disclosure as defined by the appended claims and their equivalents.

Claims

1. A method for performing access deregistration via an Access and Mobility Management Function (AMF) serving both 3GPP access and non-3GPP access, the method comprising: In the PLMN, a temporary identifier is assigned to the terminal during the registration process via 3GPP access, wherein the assigned temporary identifier is reused in the PLMN during the registration process for the terminal via non-3GPP access. After the terminal registers via 3GPP access and non-3GPP access, it is determined to initiate a deregistration process via 3GPP access to deregister the terminal on non-3GPP access; and Based on the determination, a request is sent to the Session Management Function (SMF) to release Protocol Data Unit (PDU) sessions associated with non-3GPP access, the request including the PDU session ID, wherein all PDU sessions associated with non-3GPP access are released.

2. The method of claim 1, further comprising: When the deregistration process is initiated by the terminal, the deregistration request message is received from the terminal via 3GPP access in order to deregister the terminal on a non-3GPP access. as well as Send a deregistration acceptance message to the terminal via 3GPP access, corresponding to the deregistration request message.

3. The method as described in claim 1, wherein, When the terminal is outside the coverage area of ​​a non-3GPP access point, the deregistration process is initiated by the terminal.

4. The method of claim 1, wherein, The deregistration process is initiated when the terminal cannot use non-3GPP access.

5. The method of claim 1, further comprising: Separate registration management is implemented for 3GPP access and non-3GPP access. The process of initiating the deregistration process also includes: In cases where the terminal cannot use non-3GPP access, determine the timer associated with the operation of non-3GPP access; and Identify timer expirations associated with non-3GPP access.

6. An Access and Mobility Management Function (AMF) for performing access deregistration for serving 3GPP access and non-3GPP access, the AMF comprising: transceiver; as well as A controller, coupled to and configured to control the transceiver to: In the PLMN, a temporary identifier is assigned to the terminal during the registration process for 3GPP access. This assigned temporary identifier is reused in the PLMN during the registration process for the terminal for non-3GPP access. After the terminal registers via 3GPP access and non-3GPP access, it is determined that a deregistration process will be initiated via 3GPP access to deregister the terminal on non-3GPP access. The transceiver sends a request to the Session Management Function (SMF) via a determination to release Protocol Data Unit (PDU) sessions associated with non-3GPP access. The request includes a PDU session ID, wherein all PDU sessions associated with non-3GPP access are released.

7. The AMF as described in claim 6, wherein, The control is also configured to: When the deregistration process is initiated by the terminal, the transceiver receives the deregistration request message from the terminal via 3GPP access to deregister the terminal on a non-3GPP access. as well as The transceiver sends a deregistration acceptance message corresponding to the deregistration request message to the terminal via 3GPP access.

8. The AMF as described in claim 6, wherein, When the terminal is outside the coverage area of ​​a non-3GPP access point, the deregistration process is initiated by the terminal.

9. The AMF as described in claim 6, wherein, The deregistration process is initiated when the terminal cannot use non-3GPP access.

10. The AMF as claimed in claim 6, wherein, The control is also configured to: Separate registration management is implemented for 3GPP access and non-3GPP access. In cases where the terminal cannot use non-3GPP access, determine the timer associated with the operation of non-3GPP access, and Identify timer expirations associated with non-3GPP access.

11. A method for unregistering an access device via a terminal, the method comprising: During the registration process for access via 3GPP in the PLMN, an assigned temporary identifier is received from the Access and Mobility Management Function (AMF), wherein the assigned temporary identifier is reused in the PLMN during the registration process for the terminal for access via non-3GPP. Among them, after the terminal registers through 3GPP access and non-3GPP access, the deregistration process through 3GPP access is initiated by AMF to deregister the terminal on non-3GPP access. Specifically, a request to release Protocol Data Unit (PDU) sessions associated with non-3GPP access is sent from the AMF to the Session Management Function (SMF). The request includes the PDU session ID, and all PDU sessions associated with non-3GPP access are released.

12. The method of claim 11, further comprising: When the deregistration process is initiated by the terminal, a deregistration request message is sent to the AMF via 3GPP access in order to deregister the terminal on a non-3GPP access. as well as Receive the deregistration acceptance message corresponding to the deregistration request message from the AMF via 3GPP access.

13. The method of claim 11, wherein, When the terminal is outside the coverage area of ​​a non-3GPP access point, the deregistration process is initiated by the terminal.

14. The method of claim 11, wherein, The deregistration process is initiated when the terminal cannot use non-3GPP access.

15. The method of claim 11, wherein, Separate registration management is performed for 3GPP access and non-3GPP access. In cases where the terminal cannot use non-3GPP access, the timer associated with non-3GPP access is operated, and Among them, timer expiration associated with non-3GPP access is identified through AMF.

16. A terminal for performing access deregistration, the terminal comprising: transceiver; as well as A controller, coupled to and configured to control the transceiver to: During the registration process via 3GPP access in the PLMN, an assigned temporary identifier is received from the Access and Mobility Management Function (AMF) via the transceiver. This assigned temporary identifier is reused within the PLMN during the registration process for a terminal via non-3GPP access. Among them, after the terminal registers through 3GPP access and non-3GPP access, the deregistration process through 3GPP access is initiated by AMF to deregister the terminal on non-3GPP access. Specifically, a request to release Protocol Data Unit (PDU) sessions associated with non-3GPP access is sent from the AMF to the Session Management Function (SMF). The request includes the PDU session ID, and all PDU sessions associated with non-3GPP access are released.

17. The terminal as claimed in claim 16, wherein, The control is also configured to: When the deregistration process is initiated by the terminal, a deregistration request message is sent to the AMF via the transceiver through 3GPP access to deregister the terminal on a non-3GPP access. The transceiver accesses 3GPP via the transceiver and receives the deregistration acceptance message corresponding to the deregistration request message from the AMF.

18. The terminal as claimed in claim 16, wherein, When the terminal is outside the coverage area of ​​a non-3GPP access point, the deregistration process is initiated by the terminal.

19. The terminal as claimed in claim 16, wherein, The deregistration process is initiated when the terminal cannot use non-3GPP access.

20. The terminal as claimed in claim 16, wherein, Separate registration management is performed for 3GPP access and non-3GPP access. In cases where the terminal cannot use non-3GPP access, the timer associated with non-3GPP access is operated, and Among them, timer expiration associated with non-3GPP access is identified through AMF.

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