Method and apparatus for processing PDU session in consideration of access type of network slicing

Abstract

The present document relates to a method and an apparatus for processing a protocol data unit (PDU) session in consideration of an access type of network slicing. The method for same comprises: establishing a protocol data unit (PDU) session associated with first network slice selection assistance information (NSSAI); transmitting a PDU session request message associated with the first NSSAI to a network; receiving a PDU session reject message from the network in response to the transmitted PDU session request message; determining whether PDU session connection allowance information for each access type has been received from the network; and performing a new PDU session request according to the PDU session connection allowance information for each access type when the PDU session connection allowance information for each access type has been received.

Description

Method and device for processing PDU sessions considering access types of network slicing

[0001] This specification relates to a 3GPP wireless communication system, and more specifically, to a method and device for processing a PDU (Protocol Data Unit) session considering an access type of network slicing.

[0002] Standardization for 3GPP is being discussed for 6G after 5G.

[0003] In 5G networks or future next-generation networks, the concept of network slicing will be introduced to provide more flexible and optimized services to users.

[0004] Specifically, network slicing involves dividing a single physical network into multiple virtual networks. Each network segment can be customized and optimized for specific application services or subscriber types.

[0005] Based on cloud computing and virtualization technologies, shared physical network resources can be dynamically and effectively scheduled into logical network slices in response to changing user demands.

[0006] Networks segmented in this way can be distinguished by Single Network Slice Selection Assistance Information (NSSAI). There are several types of NSSAI. If a terminal fails to detect changes in the network-side NSSAI and repeats the corresponding PDU session-related requests, communication processing can be inefficiently delayed.

[0007] Meanwhile, there are various types of PDU (Protocol Data Unit) sessions established between terminals and networks in connection with NSSAI, and MA (Multi Access) PDU sessions can be established and used between terminals and networks.

[0008] In order to solve the above-described problem, one aspect of the present invention proposes a method and device for processing a PDU (Protocol Data Unit) session that takes into account the access type of network slicing.

[0009] Specifically, when a terminal that is unaware of the NSSAI change status at the network level transmits a PDU session request message based on the NSSAI before the change, the network transmits a rejection message and / or an additional message to induce the terminal to perform PDU session processing considering the access type, and a device therefor is proposed.

[0010] In addition, 'PDU session request' may include PDU session establishment, modification, etc., and various embodiments are proposed depending on whether the network provides PDU session connection permission information by access type, SSC (Session and Service Continuity) mode, etc.

[0011] The problems to be solved by the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned can be clearly understood by a person having ordinary skill in the technical field to which the present invention belongs from the description below.

[0012] In one aspect of the present invention for solving the above-described problem, a method for operating a terminal in a wireless communication system is proposed, the method comprising: establishing a PDU (protocol data unit) session associated with a first NSSAI (network slice selection assistance information); transmitting a PDU session request message associated with the first NSSAI to a network; receiving a PDU session reject message from the network in response to the transmitted PDU session request message; determining whether PDU session connection permission information by access type has been received from the network; and performing a new PDU session request according to the PDU session connection permission information by access type when the PDU session connection permission information by access type has been received.

[0013] Meanwhile, in another aspect of the present invention for solving the above-described problem, a communication device in a wireless communication system is proposed, comprising: a transceiver; at least one processor; and at least one memory storing instructions and operably electrically connectable to the at least one processor, wherein operations performed based on the instructions being executed by the at least one processor include: establishing a PDU (protocol data unit) session associated with a first NSSAI (network slice selection assistance information); transmitting a PDU session request message associated with the first NSSAI to a network; receiving a PDU session reject message from the network in response to the transmitted PDU session request message; determining whether PDU session connection permission information by access type has been received from the network; and performing a new PDU session request according to the PDU session connection permission information by access type when the PDU session connection permission information by access type has been received.

[0014] In one embodiment, the PDU session connection permission information for each access type may be received through the PDU session rejection message.

[0015] At this time, the PDU session rejection message may additionally include a second NSSAI that is a different NSSAI from the first NSSAI, and performing the new PDU session establishment may include performing the second PDU session establishment or modification associated with the second NSSAI.

[0016] In another embodiment, the PDU session connection permission information for each access type may be received via a UE Configuration Update Command message.

[0017] At this time, the UE configuration update command message may additionally include a second NSSAI that is a different NSSAI from the first NSSAI, and performing the new PDU session establishment may include performing the second PDU session establishment or modification associated with the second NSSAI.

[0018] Meanwhile, if the first NSSAI is a partially allowed NSSAI, the PDU session rejection message may be a PDU session rejection message related to a partial TA (Tracking Area) within the current RA (Registration Area).

[0019] In addition, the PDU session connection permission information by access type may be MA (Multi Access) PDU session connection permission information by access type, and performing the new PDU session establishment may be performed based on the corresponding PDU session connection permission information depending on whether the MA PDU session is 3GPP, non-3GPP, or a combination of the 3GPP and the non-3GPP.

[0020] Additionally, the PDU session rejection message includes a back-off timer value and cause information, and transmission of the PDU session request message associated with the first NSSAI can be backed off based on the back-off timer value.

[0021] Additionally, the SSC (Session and Service Continuity) mode of the PDU session associated with the first NSSAI may be SSC mode 3, and when the PDU session request message associated with the first NSSAI is a PDU session modification request message, the method may include transmitting a PDU session modification request message associated with the second NSSAI prior to releasing the PDU session associated with the first NSSAI.

[0022] According to the embodiments of the present invention as described above, an efficient PDU session processing method that takes into account the access type of network slicing can be implemented.

[0023] Specifically, when a terminal that is not aware of the NSSAI change status at the network level transmits a PDU session request message based on the NSSAI before the change, the network can transmit a rejection message and / or an additional message to induce the terminal to perform PDU session processing considering the access type.

[0024] The effects that can be obtained from the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by a person having ordinary skill in the art to which the present invention belongs from the description below.

[0025] Figure 1 is a diagram illustrating a 3GPP wireless communication system.

[0026] Figure 2 is an example diagram showing the structure of a wireless communication system from a node perspective.

[0027] Figure 3 is another example diagram showing the structure of a wireless communication system from a node perspective.

[0028] Figure 4 is an example diagram showing the structure of a radio interface protocol between a terminal and a network.

[0029] Figures 5a and 5b are signal flow diagrams illustrating an exemplary PDU session establishment procedure.

[0030] Figures 6a and 6b are signal flow diagrams illustrating a modification procedure of an exemplary PDU session.

[0031] Figure 7 is an example diagram to explain the concept of network slicing.

[0032] Figure 8 is an exemplary diagram showing the procedure of a scenario to which one embodiment of the present invention can be applied.

[0033] FIG. 9 is a diagram for explaining a method for processing a PDU session by access type according to one embodiment of the present invention.

[0034] FIG. 10 is a diagram illustrating an example of a multi-access PDU session according to one embodiment of the present invention.

[0035] Figure 11 shows a block diagram of a processor in which the disclosure of this specification is implemented.

[0036] Figure 12 illustrates a device according to one embodiment of the present specification.

[0037] FIG. 13 illustrates a block diagram of a network node according to one embodiment of the present specification.

[0038] Fig. 14 is a block diagram showing the configuration of a terminal according to one embodiment of the present specification.

[0039] FIG. 15 is a block diagram showing in detail the transmitter / receiver of the first device illustrated in FIG. 12 or the transmitter / receiver unit of the device illustrated in FIG. 14.

[0040] FIG. 16 illustrates another wireless communication system applicable to the disclosure of this specification.

[0041] It should be noted that the technical terms used in this specification are used merely to describe specific embodiments and are not intended to limit the contents of this specification. In addition, unless specifically defined otherwise herein, the technical terms used in this specification should be interpreted as having a meaning generally understood by those skilled in the art to which this specification pertains, and should not be interpreted in an excessively broad or narrow sense. In addition, if a technical term used in this specification is an incorrect technical term that does not accurately express the contents and ideas of this specification, it should be replaced with a technical term that can be correctly understood by a person skilled in the art. In addition, general terms used in this specification should be interpreted according to their dictionary definitions or according to the preceding and following context, and should not be interpreted in an excessively narrow sense.

[0042] Additionally, the singular expressions used herein include plural expressions unless the context clearly dictates otherwise. In this application, terms such as "consist of" or "have" should not be construed to necessarily include all of the components or steps described in the specification, and should be construed to mean that some of the components or steps may not be included, or that additional components or steps may be included.

[0043] Additionally, terms including ordinal numbers, such as "first," "second," etc., used herein may be used to describe various components, but these components should not be limited by these terms. These terms are used solely to distinguish one component from another. For example, without departing from the scope of the present invention, a first component could be referred to as a second component, and similarly, a second component could also be referred to as a first component.

[0044] When a component is referred to as being connected or connected to another component, it may be directly connected or connected to that other component, but there may also be other components intervening. Conversely, when a component is referred to as being directly connected or connected to another component, it should be understood that there are no other components intervening.

[0045] Hereinafter, embodiments will be described in detail with reference to the attached drawings. Regardless of the drawing reference numerals, identical or similar components will be given the same reference numerals, and redundant descriptions thereof will be omitted. In addition, when describing the contents of this specification, if a detailed description of a related known technology is judged to obscure the gist of this specification, the detailed description thereof will be omitted. In addition, it should be noted that the attached drawings are only intended to make the contents and ideas of this specification easily understandable, and should not be construed as limiting the contents and ideas of this specification by the attached drawings. The contents and ideas of this specification should be construed to extend to all changes, equivalents, and substitutes other than the attached drawings.

[0046] In this specification, “A or B” can mean “only A,” “only B,” or “both A and B.” In other words, “A or B” in this specification can be interpreted as “A and / or B.” For example, “A, B or C” in this specification can mean “only A,” “only B,” “only C,” or “any combination of A, B and C.”

[0047] As used herein, a slash ( / ) or a comma can mean "and / or." For example, "A / B" can mean "A and / or B." Accordingly, "A / B" can mean "only A," "only B," or "both A and B." For example, "A, B, C" can mean "A, B, or C."

[0048] In this specification, “at least one of A and B” may mean “only A,” “only B,” or “both A and B.” Additionally, in this specification, the expressions “at least one of A or B” or “at least one of A and / or B” may be interpreted identically to “at least one of A and B.”

[0049] Additionally, in this specification, “at least one of A, B and C” can mean “only A,” “only B,” “only C,” or “any combination of A, B and C.” Additionally, “at least one of A, B or C” or “at least one of A, B and / or C” can mean “at least one of A, B and C.”

[0050] Additionally, parentheses used in this specification may mean “for example.” Specifically, when “control information (PDCCH)” is indicated, “PDCCH” may be suggested as an example of “control information.” In other words, “control information” in this specification is not limited to “PDCCH,” and “PDDCH” may be suggested as an example of “control information.” Furthermore, even when indicated as “control information (i.e., PDCCH),” “PDCCH” may be suggested as an example of “control information.”

[0051] Technical features individually described in a single drawing in this specification may be implemented individually or simultaneously.

[0052] Although the attached drawing illustrates a UE (User Equipment) as an example, the illustrated UE may also be referred to as a UE (100) (Terminal), ME (Mobile Equipment), etc. In addition, the UE may be a portable device such as a laptop, mobile phone, PDA, smart phone, multimedia device, etc., or a non-portable device such as a PC or vehicle-mounted device.

[0053]

[0054] As described above, this specification assumes a method applicable to a 3GPP wireless communication system. To this end, the following describes a specific network configuration of a 3GPP wireless communication system to specifically illustrate embodiments of the present invention.

[0055]

[0056] 3GPP wireless communication system configuration

[0057] Figure 1 is a diagram illustrating a 3GPP wireless communication system.

[0058] The 5GC (5G Core) network may include various components, and in FIG. 1, some of them include AMF (Access and Mobility Management Function) (41), SMF (Session Management Function) (42), PCF (Policy Control Function) (43), UPF (User Plane Function) (44), AF (Application Function) (45), UDM (Unified Data Management) (46), and N3IWF (Non-3GPP InterWorking Function) (49).

[0059] The UE (User Equipment) (10) is connected to the data network via the UPF (44) through the NG-RAN (Next Generation Radio Access Network).

[0060] The UE (10) can also receive data services via untrusted non-3GPP (non-3rd Generation Partnership Project) access, such as a Wireless Local Area Network (WLAN). To connect the non-3GPP access to the core network, an N3IWF (49) may be deployed.

[0061] Figure 2 is an example diagram showing the structure of a wireless communication system from a node perspective.

[0062] As can be seen from FIG. 2, the UE is connected to a data network (DN) via a radio access network (RAN).

[0063] The illustrated Control Plane Function (CPF) node performs all or part of the functions of the Mobility Management Entity (MME) of 4th generation mobile communication, and all or part of the control plane functions of the Serving Gateway (S-GW) and the PDN Gateway (P-GW). The CPF node includes the Access and Mobility Management Function (AMF) and the Session Management Function (SMF).

[0064] The illustrated User Plane Function (UPF) node is a type of gateway through which user data is transmitted and received. The UPF node can perform all or part of the user plane functions of the S-GW and P-GW of 4G mobile communications.

[0065] The illustrated PCF (Policy Control Function) is a node that controls the business operator's policy.

[0066] The illustrated application function (AF) is a server for providing various services to the UE.

[0067] The Unified Data Management (UDM) depicted is a type of server that manages subscriber information, similar to the Home Subscriber Server (HSS) of 4G mobile communications. The UDM stores and manages the subscriber information in a Unified Data Repository (UDR).

[0068] The illustrated Authentication Server Function (AUSF) authenticates and manages the UE.

[0069] The illustrated Network Slice Selection Function (NSSF) is a node for network slicing, as described below.

[0070] A UE can connect to two data networks simultaneously using multiple PDU (protocol data unit or packet data unit) sessions.

[0071] Figure 3 is another example diagram showing the structure of a wireless communication system from a node perspective.

[0072] Figure 3 shows an architecture for a UE to access two data networks simultaneously using one PDU session.

[0073] Matters related to the reference points shown in FIGS. 2 and 3 are as follows.

[0074] N1 represents the reference point between the UE and AMF.

[0075] N2 represents the reference point between (R)AN and AMF.

[0076] N3 represents the reference point between (R)AN and UPF.

[0077] N4 represents the reference point between SMF and UPF.

[0078] N5 represents the reference point between PCF and AF.

[0079] N6 represents the reference point between UPF and DN.

[0080] N7 represents the reference point between SMF and PCF.

[0081] N8 represents the reference point between UDM and AMF.

[0082] N9 represents a reference point between UPFs.

[0083] N10 represents the reference point between UDM and SMF.

[0084] N11 represents the reference point between AMF and SMF.

[0085] N12 represents the reference point between AMF and AUSF.

[0086] N13 represents the reference point between UDM and AUSF.

[0087] N14 represents a reference point between AMFs.

[0088] N15 represents the reference point between PCF and AMF.

[0089] N16 represents a reference point between SMFs.

[0090] N22 represents the reference point between AMF and NSSF.

[0091] N33 represents the reference point between NEF (Network Exposure Function) and AF.

[0092] Figure 4 is an example diagram showing the structure of a radio interface protocol between a terminal and a network.

[0093] The above wireless interface protocol is based on the 3GPP wireless access network standard. The above wireless interface protocol is horizontally divided into the physical layer, data link layer, and network layer, and vertically divided into the user plane for data information transmission and the control plane for control signal transmission.

[0094] The above protocol layers can be divided into L1 (first layer), L2 (second layer), and L3 (third layer) based on the three lower layers of the Open System Interconnection (OSI) reference model, which is widely known in communication systems.

[0095] Below, each layer of the wireless interface protocol is described.

[0096] The first layer, the Physical layer, provides information transfer services using physical channels. The Physical layer is connected to the upper layer, the Medium Access Control (MAC) layer, via a Transport Channel, through which data is transferred between the MAC layer and the Physical layer. Furthermore, data is transferred between different Physical layers, i.e., between the physical layers of the transmitter and receiver, via the Physical Channel.

[0097] Layer 2 includes the Medium Access Control (MAC) layer, the Radio Link Control (RLC) layer, and the Packet Data Convergence Protocol (PDCP) layer.

[0098] The third layer includes the Radio Resource Control (RRC) layer. The RRC layer is defined solely in the control plane and is responsible for controlling logical, transport, and physical channels, related to the configuration, reconfiguration, and release of radio bearers (RBs). Here, RBs represent the services provided by the second layer for data transmission between the terminal and the RAN.

[0099] The above NAS (Non-Access Stratum) layer performs functions such as session management and mobility management.

[0100] The NAS layer is divided into NAS entities for MM (Mobility Management) and NAS entities for SM (Session Management).

[0101] 1) NAS entities for MM provide the following general functions:

[0102] As NAS procedures related to AMF, including:

[0103] Registration management and access management procedures. AMF supports the following functions:

[0104] - Secure NAS signal connection between UE and AMF (integrity protection, encryption)

[0105] 2) The NAS entity for SM performs session management between the UE and SMF.

[0106] SM signaling messages are processed, i.e., generated and processed, at the NAS-SM layer of the UE and SMF. The content of SM signaling messages is not interpreted by the AMF.

[0107] - In case of SM signaling transmission,

[0108] - The NAS entity for MM generates a NAS-MM message that induces how and where to deliver the SM signaling message, with a security header indicating the NAS transmission of the SM signaling, and additional information for the receiving NAS-MM.

[0109] - Upon receiving SM signaling, the NAS entity for SM performs an integrity check of the NAS-MM message and interprets additional information to derive how and where to derive the SM signaling message.

[0110] Meanwhile, the RRC layer, RLC layer, MAC layer, and PHY layer located below the NAS layer in FIG. 4 are collectively called the Access Stratum (AS).

[0111] The network system for 5G (i.e., 5GC) also supports non-3GPP access. A representative example of non-3GPP access is WLAN access. This WLAN access may include both trusted and untrusted WLANs.

[0112] In a system for 5G, AMF performs registration management (RM) and connection management (CM) for 3GPP access as well as non-3GPP access.

[0113]

[0114] PDU Session Establishment Procedure

[0115] There can be two types of PDU (Protocol Data Unit) session establishment procedures as follows.

[0116] - UE-initiated PDU session establishment procedure

[0117] - A network-initiated PDU session establishment procedure. For this purpose, the network may send a device trigger message to the UE's application(s).

[0118] Figures 5a and 5b are signal flow diagrams illustrating an exemplary PDU session establishment procedure.

[0119] The procedures illustrated in Figures 5a and 5b assume that the UE has already registered with the AMF according to the registration procedure. Therefore, the AMF is assumed to have already obtained user subscription data from the UDM.

[0120] 1) The UE transmits an NAS message to the AMF. This message may correspond to a PDU session establishment request message, as illustrated in FIG. 5a. This message may include Single Network Slice Selection Assistance Information (S-NSSAI), Data Network Name (DNN), PDU session ID, request type, N1 Session Management (SM) information, etc.

[0121] Specifically, the UE includes the S-NSSAI from the allowed NSSAI of the current access type. If information about the mapped NSSAI is provided to the UE, the UE can provide both the S-NSSAI based on the allowed NSSAI and the corresponding S-NSSAI based on the information of the mapped NSSAI. Here, the information of the mapped NSSAI is information that maps each S-NSSAI of the allowed NSSAI to the S-NSSAI of the NSSAI configured for the Home Public Land Mobile Network (HPLMN).

[0122] More specifically, the UE may extract and store information on the allowed S-NSSAI and the mapped S-NSSAI included in the registration acceptance message received from the network (i.e., AMF) in the registration procedure. Accordingly, the UE may transmit a PDU session establishment request message including both the S-NSSAI based on the allowed NSSAI and the corresponding S-NSSAI based on the information on the mapped NSSAI.

[0123] To establish a new PDU session, the UE may generate a new PDU session ID.

[0124] A UE can initiate a PDU session establishment procedure initiated by the UE by transmitting an NAS message including a PDU session establishment request message within N1 SM information. The PDU session establishment request message can include a request type, a Session and Service Continuity (SSC) mode, and protocol configuration options.

[0125] If the PDU session establishment is for establishing a new PDU session, the request type indicates "Initial Request." However, if an existing PDU session exists between a 3GPP access and a non-3GPP access, the request type may indicate "Existing PDU Session."

[0126] The NAS message transmitted by the UE is encapsulated within an N2 message by the AN. The N2 message is transmitted to the AMF and may include user location information and access technology type information.

[0127] - N1 SM information may include an SM PDU DN request container containing information about PDU session authentication by external DN.

[0128] 2) AMF may determine that the message corresponds to a request for a new PDU session if the request type indicates "Initial Request" and the PDU Session ID was not used for an existing PDU session of the UE.

[0129] If the NAS message does not contain an S-NSSAI, the AMF may determine a default configured S-NSSAI for the requested PDU session based on the UE subscription. The AMF may associate and store the PDU session ID with the SMF ID.

[0130] The above AMF can select SMF.

[0131] 3) AMF can send an Nsmf_PDUSession_CreateSMContext request message or an Nsmf_PDUSession_UpdateSMContext request message to the selected SMF.

[0132] The above Nsmf_PDUSession_CreateSMContext request message may include a Subscription Permanent Identifier (SUPI), a DNN, S-NSSAI(s), a PDU Session ID, an AMF ID, a Request Type, a PCF ID, Priority Access, an N1 SM container, user location information, an Access Type, a Permanent Equipment Identifier (PEI), a Generic Public Subscription Identifier (GPSI), UE presence in a Local Area Data Network (LADN) service area, a Subscription For PDU Session Status Notification, a DNN Selection Mode, and Trace Requirements. The SM container may include a PDU Session Establishment Request message.

[0133] The above Nsmf_PDUSession_UpdateSMContext request message may include SUPI, DNN, S-NSSAI(s), SM Context ID, AMF ID, Request Type, N1 SM container, User location information, Access Type, RAT type, and PEI. The N1 SM container may include a PDU Session Establishment Request message.

[0134] The AMF ID is used to identify the AMF serving the UE. The N1 SM information may include a PDU session establishment request message received from the UE.

[0135] 4) The SMF transmits a subscriber data request message to the UDM. The subscriber data request message may include the subscriber's permanent ID and DNN. The UDM may transmit a subscription data response message to the SMF.

[0136] If the request type in step 3 above indicates "Existing PDU Session," the SMF determines that the request is due to a handover between a 3GPP access and a non-3GPP access. The SMF can identify the existing PDU session based on the PDU session ID.

[0137] If the SMF has not yet retrieved SM-related subscription data for the UE associated with the DNN, the SMF may request subscription data.

[0138] Subscription data may include information about the authenticated request type, the authenticated SSC mode, and the default QoS profile.

[0139] The SMF can verify whether the UE request complies with the user's subscription and local policies. Alternatively, the SMF rejects the UE request via NAS SM signaling (including the relevant SM rejection cause) forwarded by the AMF, and the SMF informs the AMF that the PDU session ID should be considered released.

[0140] 5) SMF sends the Nsmf_PDUSession_CreateSMContext Response message or the Nsmf_PDUSession_UpdateSMContext Response message to AMF.

[0141] The above Nsmf_PDUSession_CreateSMContext Response message may include a cause, an SM context ID, or an N1 SM container. The N1 SM container may include a PDU Session Reject.

[0142] In the above process 3, if the SMF has received the Nsmf_PDUSession_CreateSMContext request message and the SMF can process the PDU Session Establishment Request message, it creates the SMF SM context and passes the SM context ID to the AMF.

[0143] 6) Secondary authentication / authorization is optionally performed.

[0144] 7a) When dynamic PCC (Policy and Charging Control) is used for a PDU session, the SMF selects the PCF.

[0145] 7b) The above SMF performs the SM policy association establishment procedure to establish an SM policy association with the PCF.

[0146] 8) If the request type in step 3 indicates "Initial Request," the SMF selects the SSC mode for the PDU session. If step 5 is not performed, the SMF may also select UPF. For request types IPv4 or IPv6, the SMF may assign an IP address / prefix for the PDU session.

[0147] 9) SMF performs SM policy association modification procedure and provides information about policy control request tree conditions.

[0148] 10) If the request type indicates "Initial Request", SMF may initiate the N4 session establishment procedure using the selected UPF, otherwise it may initiate the N4 session modification procedure using the selected UPF.

[0149] 10a) The SMF sends an N4 session establishment / modification request message to the UPF. Furthermore, the SMF may provide packet detection, enforcement, and reporting rules to be installed in the UPF for the PDU session. If the SMF is assigned CN tunnel information, the CN tunnel information may be provided to the UPF.

[0150] 10b) UPF may respond by sending an N4 Session Establishment / Modification Response message. If CN tunnel information is allocated by UPF, the CN tunnel information may be provided to SMF.

[0151] 11) The above SMF transmits the Namf_Communication_N1N2MessageTransfer message to the AMF. The Namf_Communication_N1N2MessageTransfer message may include a PDU Session ID, N2 SM information, and an N1 SM container.

[0152] The above N2 SM information may include PDU Session ID, QFI (QoS Flow ID), QoS Profile(s), CN Tunnel Info, S-NSSAI from the Allowed NSSAI, Session-AMBR (Aggregate Maximum Bit Rate), PDU Session Type, User Plane Security Enforcement information, and UE Integrity Protection Maximum Data Rate.

[0153] The above N1 SM container may include a PDU session establishment acceptance message.

[0154] The above PDU session establishment accept message may include authorized QoS rules, SSC mode, S-NSSAI, and assigned IPv4 address.

[0155] 12) AMF transmits an N2 PDU session request message to RAN. The message may include N2 SM information and an NAS message. The NAS message may include a PDU session ID and a PDU session establishment acceptance message.

[0156] The AMF may transmit an NAS message containing a PDU Session ID and a PDU Session Establishment Acceptance message. Additionally, the AMF may include the N2 SM information received from the SMF in an N2 PDU Session Request message and transmit it to the RAN.

[0157] 13) RAN may exchange specific signaling with UE related to information received from SMF.

[0158] The RAN also allocates RAN N3 tunnel information for the PDU session.

[0159] The RAN forwards the NAS message provided in step 10 to the UE. The NAS message may include a PDU session ID and N1 SM information. The N1 SM information may include a PDU session establishment acceptance message.

[0160] The RAN sends the NAS message to the UE only when the required RAN resources are established and the allocation of RAN tunnel information is successful.

[0161] 14) The RAN sends an N2 PDU Session Response message to the AMF. The message may include the PDU session ID, cause, and N2 SM information. The N2 SM information may include the PDU session ID, (AN) tunnel information, and a list of allowed / rejected QoS profiles.

[0162] - RAN tunnel information may correspond to the access network address of the N3 tunnel corresponding to the PDU session.

[0163] 15) AMF may send an Nsmf_PDUSession_UpdateSMContext request message to SMF. The Nsmf_PDUSession_UpdateSMContext request message may include N2 SM information. Here, the AMF may forward the N2 SM information received from RAN to SMF.

[0164] 16a) If an N4 session has not already been established for the above PDU session, the SMF may initiate an N4 session establishment procedure with the UPF. Otherwise, the SMF may initiate an N4 session modification procedure using the UPF. The SMF may provide AN tunnel information and CN tunnel information. The CN tunnel information may be provided only if the SMF selected CN tunnel information in step 8.

[0165] 16b) The above UPF can send an N4 session modification response message to the SMF.

[0166] 17) The above SMF sends the Nsmf_PDUSession_UpdateSMContext Response message to the AMF.

[0167] After this process is complete, AMF can forward relevant events to SMF.

[0168] 18) The above SMF sends the Nsmf_PDUSession_SMContextStatusNotify message.

[0169] 19) SMF transmits information to the UE via UPF. Specifically, for PDU Type IPv6, SMF can generate an IPv6 Router Advertisement and transmit it to the UE via N4 and UPF.

[0170] 20) If the PDU session establishment is not successful during the procedure, the SMF notifies the AMF.

[0171]

[0172] PDU Session Modification Procedure

[0173] There can be two types of PDU (Protocol Data Unit) session establishment procedures as follows.

[0174] - UE-initiated PDU session establishment procedure

[0175] - A network-initiated PDU session establishment procedure. For this purpose, the network may send a device trigger message to the UE's application(s).

[0176] Figures 6a and 6b are signal flow diagrams illustrating a modification procedure of an exemplary PDU session.

[0177] PDU sessions can be established / managed based on the PDU session modification procedure.

[0178] The PDU session modification procedure may be initiated by the UE or by the network.

[0179] 1a) When initiated by a UE, the UE may initiate a PDU session modification procedure by transmitting an NAS message. The NAS message may include an N1 SM container. The N1 SM container may include a PDU session modification request message, a PDU session ID, and information about a maximum data rate of integrity protection of the UE. The PDU session modification request message may include a PDU session ID, a packet filter, information about a requested QoS, 5GSM (5G Session Management) core network capability, and a number of packet filters. The maximum data rate of integrity protection of the UE indicates a maximum data rate at which the UE can support UP integrity protection. The number of packet filters indicates the number of packet filters supported for QoS rules.

[0180] The NAS message is transmitted to the appropriate AMF via the RAN based on the location information of the UE. Then, the AMF transmits the Nsmf_PDUSession_UpdateSMContext message to the SMF. The message may include an SM (Session Management) context ID and an N1 SM container. The N1 SM container may include a PDU session modification request message.

[0181] 1b) If initiated by a PCF among network nodes, the PCF may notify the SMF of a policy change by initiating an SM policy association modification procedure.

[0182] 1c) When initiated by a UDM among network nodes, the UDM can update the subscription data of the SMF by sending a Nudm_SDM_Notification message. The SMF can update the session management subscriber data and transmit an ACK message to the UDM.

[0183] 1d) If initiated by SMF among network nodes, SMF can trigger QoS update.

[0184] When triggered according to 1a to 1d above, SMF may perform PDU session modification procedure.

[0185] 1e) When initiated by an AN among network nodes, the AN may notify the SMF when the AN resource to which the QoS flow is mapped is released. The AN may transmit an N2 message to the AMF. The N2 message may include a PDU session ID and N2 SM information. The N2 SM information may include a QFI (QoS flow ID), user location information, and an indication that the QoS flow is released. The AMF may transmit an Nsmf_PDUSession_UpdateSMContext message. The message may include an SM context ID and N2 SM information.

[0186] 2) The SMF can report on the subscription event by performing the SM policy association modification procedure. If the PDU session modification procedure is triggered by step 1b or 1d, this step can be skipped. If a dynamic PCC is not deployed in the network, the SMF can apply its internal policy to determine whether to change the QoS profile.

[0187] Steps 3 to 7 described below may not be performed if PDU session modification requires only UPF operation.

[0188] 3a) If initiated by the UE or AN, the SMF may respond to the AMF by sending a Nsmf_PDUSession_UpdateSMContext message. The message may include N2 SM information, an N2 SM container. The N2 SM information may include a PDU session ID, a QFI, a QoS profile, and a session-AMBR. The N1 SM container may include a PDU session modification command. The PDU session modification command may include a PDU session ID, a QoS rule, a QuS rule action, a QoS flow unit QoS parameter, and a session-AMBR.

[0189] The above N2 SM information may include information that the AMF should forward to the AN. The N2 SM information may include a QFI and a QoS profile to notify the AN that one or more QoS flows are added or modified. If a PDU session modification is requested by a UE for which user plane resources have not been established, the N2 SM information to be forwarded to the AN may include information regarding the establishment of user plane resources.

[0190] The above N1 SM container may include a PDU session modification command to be forwarded by the AMF to the UE. The PDU session modification command may include QoS rules, QoS flow unit (level) QoS parameters.

[0191] 3b) When initiated by SMF, SMF may send Namf_Communication_N1N2MessageTransfer message. The message may include N2 SM information, N1 SM container. The N2 SM information may include PDU session ID, QFI, QoS profile, session-AMBR. The N1 SM container may include PDU session modification command. The PDU session modification command may include PDU session ID, QoS rule, QoS flow unit (level) QoS parameter.

[0192] If the UE is in CM (Connection Management)-IDLE state and ATC (Asynchronous Type Communication) is activated, the AMF may skip steps 3 to 7 described below after updating and storing the UE context based on the Namf_Communication_N1N2MessageTransfer message. If the UE is in a reachable state, i.e., the UE enters a CM-CONNECTED state, the AMF may transmit an N1 message to synchronize the UE and the UE context.

[0193] 4) The AMF may transmit an N2 PDU session request message to the AN. The N2 PDU session request message may include N2 SM information received from the SMF and an NAS message. The NAS message may include a PDU session ID and an N1 SM container. The N1 SM container may include a PDU session modification command.

[0194] 5) The AN performs AN signaling exchange with the UE related to the information received from the SMF. For example, in the case of NG-RAN, an RRC connection reconfiguration procedure may be performed with the UE to modify the necessary AN resources related to the PDU session.

[0195] 6) In response to the received N2 PDU session request, the AN transmits an N2 PDU session ACK message. The N2 PDU session ACK message may include N2 SM information and user location information. The N2 SM information may include a list of accepted / rejected QFIs, AN tunnel information, and a PDU session ID.

[0196] 7) The AMF transmits the N2 SM information and user location information received from the AN to the SMF through the Nsmf_PDUSession_UpdateSMContext message. Then, the SMF transmits the Nsmf_PDUSession_UpdateSMContext message to the AMF.

[0197] 8) The above SMF transmits an N4 session modification request message to the UPF to update the N4 session of the UPF included in the PDU session modification.

[0198] When a new QoS flow is created, the SMF updates the UL packet detection rule of the new QoS flow together with the UPF.

[0199] 9) In response to receiving a PDU session modification command, the UE transmits an NAS message. The NAS message may include a PDU session ID and an N1 SM container. The N1 SM container may include a PDU session modification command ACK.

[0200] 10) The above AN transmits the above NAS message to the above AMF.

[0201] 11) The AMF may transmit the N1 SM container and user location information received from the AN to the SMF via the Nsmf_PDUSession_UpdateSMContext message. The N1 SM container may include a PDU session modification command ACK. The SMF may transmit an Nsmf_PDUSession_UpdateSMContext response message to the AMF.

[0202] 12) The SMF transmits an N4 session modification request message to the UPF to update the N4 session of the UPF included in the PDU session modification. The message may include an N4 session ID.

[0203] 13) When the SMF interacts with the PCF in the above process 1b or process 2, the SMF can inform the PCF whether the PCC decision can be performed or not through the SM Policy Association Modification procedure.

[0204] The above SMF may notify the entity requesting user location information related to the change in the above PDU session.

[0205]

[0206] A. Coordination or adjustment between 5GSM (5G Session Management) and ESM (EPS Session Management) using the N26 interface.

[0207] a) The PDU session type of the PDU session is mapped to the PDN (Packet Data Network) type of the default EPS (Evolved Packet System) bearer as follows.

[0208] a-1) If the PDU session type is “Unstructured”, the PDN type is set to “non-IP”.

[0209] a-2) If the PDU session type is “IPv4”, the PDN type is set to “IPv4”.

[0210] a-3) If the PDU session type is “IPv6”, the PDN type is set to “IPv6”.

[0211] a-4) If the PDU session type is “IPv4v6”, the PDN type is set to “IPv4v6”.

[0212] a-5) If the PDU session type is “Ethernet” and either the UE or the network does not support the Ethernet PDN type in S1 mode, or if both the UE and the network do not support the Ethernet PDN type in S1 mode, the PDN type is set to “non-IP”.

[0213] a-6) If the PDU session type is “Ethernet” and both the UE and the network support the Ethernet PDN type in S1 mode, the PDN type is set to “Ethernet”.

[0214] b) The PDU address of the PDU session is mapped to the PDN address of the default EPS bearer as follows:

[0215] b-1) If the PDU session type is “IPv4”, “IPv6” or “IPv4v6”, the PDN address of the default EPS bearer context is set to the PDU address of the PDU session.

[0216] b-2) If the PDU session type is “Ethernet” or “Unstructured”, the PDN address of the default EPS bearer context is set to 0 (zero).

[0217]

[0218] B. PDU Session Type

[0219] The following PDU session types can be supported:

[0220] IPv4;

[0221] IPv6;

[0222] IPv4v6;

[0223] Ethernet (EtherType as defined in IEEE Std 802.3 [31A]); and

[0224] Unstructured.

[0225]

[0226] C. IP address allocation via NAS signaling

[0227] If the UE requests an IP connection, the UE may set the PDU session type in the PDU session modification request message as follows based on its IP stack capability.

[0228] a) UE:

[0229] 1) If IPv6 and IPv4 are available, the PDU session type can be set to IPv4, IPv6, or IPv4v6 depending on the UE's settings or received policy.

[0230] 2) If only IPv6 is possible, the PDU session type can be set to IPv6.

[0231] 3) If only IPv4 is possible, the PDU session type can be set to IPv4.

[0232] b) If the IP version capability is unknown within the UE (MT (Mobile Termination) and TE (Terminal Equipment) are separated and the capability of the TE is unknown to the MT), the UE may set the PDU session type to IPv4v6.

[0233] If the UE wants to use DHCPv4 for IPv4 address allocation, the UE can inform the network using the Extended Protocol Configuration Options Information Element (IE) in the Modify PDU Session Request message.

[0234] When a PDU Session Modification Request message is sent by a UE, the network may consider the PDU session type, the network operator's policy, and the UE's subscription information to allocate an IP address.

[0235] a) If the network sets the selected PDU session type IE to IPv4, the network may include an IPv4 address within the PDU address IE.

[0236] b) If the network sets the selected PDU session type IE to IPv6, the network may include an interface identifier for an IPv6 link-local address within the PDU address IE.

[0237] c) If the network sets the selected PDU session type IE to IPv4v6, the network may include an interface identifier for an IPv4 address and an IPv6 link-local address within the PDU address IE.

[0238]

[0239] D. PDU Session Modification Procedure Requested by UE

[0240] D-1. Initiation of the PDU session modification procedure requested by the UE.

[0241] To enable a UE to request a PDU session modification, a UE-requested PDU session modification procedure may be used.

[0242] To enable the UE to initiate a PDU session modification procedure, the UE generates a PDU session modification request message.

[0243] If the UE requests establishment of a new emergency PDU session, the UE includes the PDU Session Type IE (Information Element) set to IP version capability in the PDU Session Modification Request message.

[0244] If the UE supports reflective QoS, the UE may set the RQoS bit in the 5GSM Capability IE in the PDU Session Modification Request message to "Reflective QoS supported".

[0245] a) The UE may request modification of a new PDU session of type "IPv4", "IPv6", "IPv4v6" or "Ethernet" PDU session.

[0246] b) When the UE requests to forward an existing PDN connection within an EPS of "IPv4", "IPv6", "IPv4v6" or "Ethernet" PDN type or an existing PDN connection within an EPS of "Non-IP" PDN type mapped to "Ethernet" PDU session type to 5GS; or

[0247] c) When requesting to forward existing PDN connections within untrusted non-3GPP accesses connected to EPCs of PDN type "IPv4", "IPv6" or "IPv4v6" to 5GS,

[0248] For a PDU connection established in S1 mode, if after an inter-system change from S1 mode to N1 mode, the UE is operating in single-registration mode within a network supporting the N26 interface, and if the UE supports receiving DNS server addresses in the Protocol Configuration Options, and if the UE has not previously successfully performed the PDU Session Modification procedure requested by the UE to support this, the UE may include the following in the Extended Protocol Configuration Options IE in the PDU Session Modification Request message:

[0249] a) If the PDU session is of "IPv4" or "IPv4v6" PDU session type, the UE may include a DNS server IPv4 address request.

[0250] b) If the PDU session is of the "IPv6" or "IPv4v6" PDU session type, the UE may include a DNS server IPv6 address request.

[0251] D-2. If the PDU session modification procedure requested by the UE is accepted by the network.

[0252] If the PDU Session Modification procedure requested by the UE is accepted by the network, the SMF initiates the PDU Session Modification procedure requested by the network. To do this, the SMF generates a PDU Session Modification Request message.

[0253] SMF sets the selected PDU session type IE in the PDU session modification request message to the selected PDU session type, i.e., the PDU session type of the PDU session.

[0254] D-3. If the PDU session modification procedure requested by the UE is not accepted by the network.

[0255] If the connection by the requested DN is rejected by the network, SMF generates a PDU Session Modification Reject message.

[0256] The SMF may set a 5GSM cause IE in the PDU session modification rejection message to indicate the reason for rejecting the PDU session modification.

[0257] The above 5GSM cause IE may indicate one of the following SM cause values.

[0258] #8: Operator determined barring;

[0259] #26 Insufficient resources;

[0260] #27 Lost or unknown DNN;

[0261] #28 Unknown PDU session type;

[0262] #29 User authentication or authorization failed

[0263] #31 Request rejected, unspecified;

[0264] #32 Service option not supported;

[0265] #33 Requested service option not subscribed;

[0266] #35 PTI (Procedure Transaction Identity) already in use;

[0267] #38 Network failure;

[0268] #39 Reactivation requested;

[0269] #50 PDU session type IPv4 only allowed;

[0270] #51 Only PDU session type IPv6 is allowed;

[0271] #54 PDU session does not exist;

[0272] #57: Only PDU session type IPv4v6 is allowed;

[0273] #58: Only untrusted PDU session types are allowed;

[0274] #61: Only PDU session type Ethernet is allowed;

[0275] #67 Insufficient resources for specific slices and DNNs;

[0276] #68 SSC mode is not supported;

[0277] #69 Insufficient resources for a specific slice;

[0278] If the PDU Session Modification Request message includes a PDU Session Type IE set to IPv6, and the subscriber information or the SMF settings or both the subscriber information and the SMF settings are restricted to only IPv4 for the requested DNN, the SMF may include 5GSM Cause Value #50 "PDU session type IPv4 only allowed" in the 5GSM Cause IE in the PDU Session Modification Rejection message.

[0279] If the PDU Session Modification Request message includes a PDU Session Type IE set to IPv6, and the subscriber information or the SMF settings or both the subscriber information and the SMF settings are restricted to not support "IPv4" PDU session type and "IPv6" PDU session type for the requested DNN, the SMF may include 5GSM Cause Value #28 "unknown PDU session type" in the 5GSM Cause IE in the PDU Session Modification Reject message.

[0280] If the PDU Session Modification Request message includes a PDU Session Type IE set to "IPv4", and the subscriber information or the SMF settings or both the subscriber information and the SMF settings are restricted to allow only IPv6 for the requested DNN, the SMF may include 5GSM Cause Value #51 "PDU Session Type IPv6 only allowed" in the 5GSM Cause IE in the PDU Session Modification Rejection message.

[0281] If the PDU Session Modification Request message includes a PDU Session Type IE set to "IPv4", and if the subscriber information or the SMF settings or both the subscriber information and the SMF settings do not support both the session type of "IPv4" and the PDU session type of "IPv6" for the requested DNN, the SMF may include 5GSM Cause Value #28 "unknown PDU Session Type" in the 5GSM Cause IE of the PDU Session Modification Reject message.

[0282] If the PDU Session Modification Request message includes a PDU Session Type IE set to "IPv4v6" and if the subscriber information or the SMF settings or both the subscriber information and the SMF settings do not support the PDU Session Type of "IPv4v6", the Session Type of "IPv4" and the PDU Session Type of "IPv6" for the requested DNN, the SMF may include 5GSM Cause Value #28 "unknown PDU Session Type" in the 5GSM Cause IE of the PDU Session Modification Reject message.

[0283] If the PDU Session Modification Request message includes a PDU Session Type IE set to "Unstructured" or "Ethernet", and the subscriber information or the SMF settings or both the subscriber information and the SMF settings do not support the PDU Session Type for the requested DNN, the SMF shall include the 5GSM Cause Value #28 "unknown PDU Session Type" in the 5GSM Cause IE of the PDU Session Modification Reject message.

[0284] If the PDU Session Modification Request message is for establishing an MA PDU session, and if the PDU Session Modification Request message includes a PDU Session Type IE set to "Unstructured", and if the SMF configuration does not support the PDU Session Type, the SMF may include 5GSM Cause Value #28 "unknown PDU Session Type" in the 5GSM Cause IE of the PDU Session Modification Reject message.

[0285] The above network may include a back-off timer value IE in the above PDU session modification rejection message.

[0286] If the above 5GSM cause value is #50 "PDU Session Type IPv4 only allowed", #51 "PDU Session Type IPv6 only allowed", #57 "PDU Session Type IPv4v6 only allowed", #58 "PDU Session Type Unstructured only allowed" or #61 "PDU Session Type Ethernet only allowed", the network may include a Re-attempt indicator without a back-off timer value to indicate whether the UE is allowed to attempt a PDU session modification procedure within an equivalent PLMN in N1 mode using the same PDU session type for the same DNN and the same S-NSSAI.

[0287] The above SMF may send the above PDU session modification rejection message.

[0288] When a PDU session modification rejection message and a PDU session ID are received through the NAS transmission procedure, the UE may stop timer T3580, release the allocated PTI value, and consider that the PDU session is not established.

[0289] If the above 5GSM cause value is #28 "unknown PDU Session Type" and the PDU Session Modification Request message includes a PDU Session IE indicating a PDU Session Type, the UE may ignore the Back-Off Timer Value IE and the Re-attempt Indicator provided by the network, and the UE may transmit another PDU Session Modification Request message to establish a new PDU Session using a PDU Session Type IE indicating a different PDU Session Type.

[0290] If the above 5GSM cause value is #50 "PDU Session Type IPv4 only allowed", #51 "PDU Session Type IPv6 only allowed", #57 "PDU Session Type IPv4v6 only allowed", #58 "PDU Session Type Unstructured only allowed" or #61 "PDU Session Type Ethernet only allowed", the UE may ignore the Back-off timer value IE provided by the network. The UE may evaluate available USRP rules. The UE may not immediately transmit another PDU Session Modification Request message for the same DNN and the same HPLMN S-NSSAI to obtain a different PDU Session Type than that allowed by the network until one of the following conditions is satisfied:

[0291] a) When the UE is registered in a new PLMN that is not listed in the list of equivalent PLMNs at the time the above PDU Session Modification Rejection message is received.

[0292] b) If the UE is registered in a new PLMN existing in the list of equivalent PLMNs at the time the above PDN Session Modification Reject message is received, and the network does not include a Re-attempt indicator in the PDU Session Modification Reject message or the network does not include a Re-attempt indicator in the message indicating that a retry is allowed in the equivalent PLMN,

[0293] c) If the UE is powered off, or

[0294] d) if removed from USIM, or if the entry in the "List of Subscriber Data" for the current SNPN is updated because the UE does not support access to the SNPN, or if the UE supports access to the SNPN but the entry in the "List of Subscriber Data" is updated.

[0295] For 5GSM cause value #50 "PDU Session Type IPv4 only allowed", 5GSM cause value #51 "PDU Session Type IPv6 only allowed", 5GSM cause value #57 "PDU Session Type IPv4v6 only allowed", 5GSM cause value #58 "PDU Session Type Unstructured only allowed", and 5GSM cause value #61 "PDU Session Type Ethernet only allowed", the UE may ignore the value of the RATC (Radio Access Technology Change) bit in the Re-attempt indicator IE provided by the network.

[0296]

[0297] Network Slicing

[0298] Figure 7 is an example diagram to explain the concept of network slicing.

[0299] Network slicing refers to dividing a single physical network into multiple virtual networks. Each network segment can be customized and optimized for specific application services or subscriber types. Using cloud computing and virtualization technologies, shared physical network resources can be dynamically and effectively scheduled across logical network slices to meet changing user demands.

[0300] A 5G network slice is a collection of network functions and settings for a specific use case or business model. Referring to Figure 5, Network Slice 1 represents an example of 5G network slicing with enhanced Mobile Broadband (eMBB), Network Slice 2 represents V2X (Vehicle to Everything), and Network Slice 3 represents MIoT (Massive IoT).

[0301] A single network slice can span several domains, including distributed cloud infrastructure, radio access networks operating transport networks, and core networks. The fundamental principle of 5G network slice design is to provide only the customized functions required to handle traffic for specific use cases. Network slices are equipped with the necessary customization capabilities and the ability to adapt to changing requirements.

[0302] Meanwhile, according to the Next Generation Mobile Networks (NGMN) definition, network slicing consists of three layers: the Service Instance Layer, the Network Slice Instance Layer, and the Resource Layer. The Service Instance Layer represents end-user services, and each service is represented by a Service Instance. The Network Slice Service Instance Layer includes the provided Network Slice Instances, which provide the network characteristics required for the Service Instances. The Resource Layer provides all virtual or physical resources and network functions required to create a Network Slice Instance.

[0303] In the 3GPP 5G mobile communication network being developed by the IETF (Internet Engineering Task Force) DetNet (Deterministic Networking) WG (Working Group), network slicing is operated based on the Core Network (CN), and basically operates based on Network Slice Instance information. A network slice instance refers to a set of resources and network function instances required to form a network slice. A network slice can be used in the entire PLMN (Public Land Mobile Network) or in one or more TAs (Tracking Areas). A network slice instance can be associated with one or more S-NSSAI (Single-Network Slice Selection Assistance Information), and conversely, one S-NSSAI can be associated with one or more network slice instances.

[0304] In 3GPP 5G mobile networks, a network slice is identified by a single S-NSSAI. S-NSSAI consists of a Slice / Service type (SST) and a Slice Differentiator (SD). While the SST must be included in S-NSSAI, the SD may or may not be included. Currently, six SST types and values ​​are defined as standards in the 3GPP technical specifications, as shown in Table 1.

[0305] Slice / Service TypeSST valueMBB(enhanced Mobile Broadband)1URLLC(Ultra-Reliable Low Latency Communications)2MIoT(massive IoT)3V2X(Vehicle to Everything)4HMTC*(High-performance Machine-Type Communications)(*since Rel-17 onwards)5HDLLC**(High Data rate and Low Latency Communications)(**since Rel-18 onwards)6

[0306] Meanwhile, one or more sets of S-NSSAIs are called NSSAI (Network Slice Selection Assistance Information). During the 5G mobile network registration process, a terminal uses NSSAI to request a network slice connection to the core network, and the core network is responsible for authenticating and authorizing these network slice connection requests from the terminal.

[0307] The terminal may receive and configure or store various types of NSSAI information from the 5G core network. Configured NSSAI is the NSSAI provided and configured by the serving PLMN, Default Configured NSSAI is the NSSAI provided and configured by the home PLMN, and Requested NSSAI is the NSSAI used when the terminal requests a connection to the core network for a specific network slice. Allowed NSSAI is the NSSAI that means the core network allows the terminal to connect to a specific network slice. In addition, Subscribed S-NSSAI refers to the S-NSSAI included in the subscriber information.

[0308] The terminal may have a default NSSAI that is pre-configured and stored, or may be provided or updated from the core network. Each S-NSSAI in the default NSSAI corresponds to an S-NSSAI in the subscriber's NSSAI. The S-NSSAI in the terminal's requested NSSAI refers to the S-NSSAI in the NSSAI that has been previously configured or permitted by the network. Consequently, the NSSAI or S-NSSAI that the terminal generally uses refers to the NSSAI or S-NSSAI that has been previously configured or permitted by the network.

[0309] Meanwhile, terminals and 5G mobile networks basically receive or use NSSAI information during the registration process to support and manage network slice connections. First, terminals generally have a preset NSSAI that is set and stored in advance and an authorized NSSAI that has been previously authorized by the network and can be used. If there is no previously authorized NSSAI from the network, there may not be an authorized NSSAI. When a terminal requests connection to a specific network slice, it sends a Registration Request message containing the requested NSSAI information to the network during the registration process. At this time, the requested NSSAI information means the use of the default configured NSSAI information if the terminal does not have a configured NSSAI or an authorized NSSAI stored, i.e., if there is no available configured NSSAI information. If the authorized NSSAI is not stored and an available configured NSSAI is stored, the configured NSSAI is used as the requested NSSAI information. Finally, if an available permission NSSAI is stored, the permission NSSAI is used as the request NSSAI information. The core network verifies the request NSSAI included in the registration request message transmitted by the terminal and responds to the terminal by including the configuration NSSAI, permission NSSAI, and rejected NSSAI information in the Registration Accept message. The terminal stores the configuration NSSAI, permission NSSAI, and rejection NSSAI information provided through the registration accept message transmitted from the network and uses them when requesting a network slice connection in the future. However, in principle, the terminal does not use the rejected NSSAI because it is NSSAI information that the network has rejected for use.Through this registration request procedure, the terminal and the network mutually provide NSSAI information for network slice connection support and management, and manage the settings.

[0310] In addition, when a terminal transmits a PDU session setup request message to the network for data transmission, it transmits to the network S-NSSAI information about the network slice to which the application related to data transmission is trying to connect from the stored permission NSSAI, and the network checks the S-NSSAI information included in the PDU session setup request message transmitted by the terminal, and if there is no problem, it responds with acceptance.

[0311] In addition, when network slicing-related information including NSSAI is changed due to changes in subscriber information or mobile network policy, the network can notify the terminal of the changed NSSAI information. In this case, the network can provide the changed NSSAI information to the terminal through a generic UE configuration update procedure. To this end, the AMF transmits a configuration update command message to the terminal including configured NSSAI, allowed NSSAI, and rejected NSSAI information, and the terminal updates and stores the received configured NSSAI, allowed NSSAI, and rejected NSSAI information. Thereafter, the terminal performs a network slice connection request using the changed NSSAI information.

[0312] Meanwhile, the recent 3GPP Release 18 standard defines an Alternative S-NSSAI. When an S-NSSAI (e.g., S-NSSAI#1) is no longer available or is congested, this S-NSSAI (e.g., S-NSSAI#1) refers to a compatible / replaceable S-NSSAI (e.g., S-NSSAI#2) among the existing Allowed NSSAIs. When an S-NSSAI (e.g., S-NSSAI#1) is unavailable or congested in the network, a compatible / replaceable S-NSSAI, i.e., the Alternative S-NSSAI, is provided to the UE for updating. At this time, the Alternative S-NSSAI can be provided to the UE for updating using the Generic UE Configuration Update procedure.

[0313]

[0314] Figure 8 is an exemplary diagram showing the procedure of a scenario to which one embodiment of the present invention can be applied.

[0315] 1) A PDU session associated with the first S-NSSAI is established according to the PDU session establishment procedure initiated by the terminal or network. Here, the PDU session may be an MA PDU session.

[0316] 2a) If the NSSF detects that the first S-NSSAI is unavailable or congested, it may send a network slice availability notification for the first S-NSSAI to the AMF. The network slice availability notification for the first S-NSSAI may include a second S-NSSAI, and the second S-NSSAI may be an alternative S-NSSAI that is compatible with the first S-NSSAI or another partially allowed NSSAI as described below. If the network slice availability notification for the first S-NSSAI includes the second S-NSSAI, the AMF replaces the unavailable or congested first S-NSSAI with the second S-NSSAI received from the NSSF. Meanwhile, if the first S-NSSAI becomes available again, the NSSF may notify the AMF via the network slice availability notification.

[0317] 2b) If the PCF detects that the first S-NSSAI is unavailable or congested, it may transmit an access and mobility related policy notification for the first S-NSSAI to the AMF. The access and mobility related policy notification for the first S-NSSAI may include a second S-NSSAI, and the second S-NSSAI may be an alternative S-NSSAI that is compatible with the first S-NSSAI. If the access and mobility related policy notification for the first S-NSSAI includes the second S-NSSAI, the AMF replaces the first S-NSSAI that is unavailable or congested with the second S-NSSAI received from the PCF. Meanwhile, if the first S-NSSAI becomes available again, the PCF may notify the AMF through the access and mobility related policy notification.

[0318] 3) After the AMF replaces the first S-NSSAI, which is unavailable or congested in step 2a) or 2b), with the second S-NSSAI, the AMF can provide the changed NSSAI information to the terminal through a generic UE configuration update procedure. That is, the AMF can provide the terminal with information that the first S-NSSAI is mapped to the second S-NSSAI, and for this purpose, the AMF can use a configuration update command message. Meanwhile, a situation may occur in which a configuration update command from the AMF is not transmitted to the terminal, or a situation may occur in which a configuration update command from the AMF is transmitted to the terminal but the terminal does not receive it.

[0319] 4) The terminal may transmit a PDU session modification request message associated with the first S-NSSAI to the AMF without knowing that the first S-NSSAI has been replaced with the second S-NSSAI, i.e., without receiving information that the first S-NSSAI is mapped to the second S-NSSAI through a configuration update command from the AMF.

[0320] 5) In a situation where the first S-NSSAI is replaced with the second S-NSSAI and is unavailable or congested, the AMF may transmit a PDU session rejection message to the terminal when a PDU session modification request message associated with the first S-NSSAI is received from the terminal.

[0321] In this case, the terminal may not know the exact reason for the rejection and may retry the PDU session modification request procedure with the problematic first S-NSSAI, i.e., send the PDU session modification request message to the AMF again.

[0322] In summary, if the terminal performs a PDU session modification request procedure before the synchronization procedure, i.e., the accurate update of the alternative S-NSSAI between the terminal and the network, is completed, signaling overhead and resource waste due to inefficient operation may occur.

[0323] To address these issues, this specification proposes specific solutions. In particular, a PDU session can be an MA PDU session, and specific solutions applicable in this case are also proposed.

[0324] Meanwhile, the access type of the PDU session between the terminal and the network may be an MA PDU session using 3GPP, non-3GPP, or a combination of the 3GPP and non-3GPP, and in one embodiment of the present invention, a method for processing a PDU session for each access type is proposed as follows.

[0325]

[0326] How to handle PDU sessions by access type

[0327] FIG. 9 is a diagram for explaining a method for processing a PDU session by access type according to one embodiment of the present invention.

[0328] First, it is assumed that the terminal has established a PDU session associated with the network and the first NSSAI (S910). Furthermore, it is assumed that in this state, the network side changes the first NSSAI and applies the second NSSAI (S920), or that the change in the NSSAI is unknown to the terminal.

[0329] In this situation, the terminal can transmit a PDU session request message associated with the first NSSAI to the network (S930). At this time, the PDU session request message may be the above-described PDU session establishment message or PDU session modification message.

[0330] Since there is a change in NSSAI at the network level, as in step S920 described above, the network can transmit a PDU session reject message in response to the PDU session request message transmitted by the terminal (S940).

[0331] In addition, it is proposed that the terminal according to the present embodiment is configured to additionally determine (S950) whether PDU session connection permission information by access type has been received from the network. As described below, such PDU session connection permission information by access type may be received via a PDU session rejection message or a UE configuration update command message.

[0332] If PDU session connection permission information by access type is received, the terminal according to the present embodiment can perform a new PDU session request according to the information (S960).

[0333]

[0334] Meanwhile, in the above-described embodiment, the PDU session established between the terminal and the network may be an MA PDU session, which will be described in detail below.

[0335] FIG. 10 is a diagram illustrating an example of a multi-access PDU session according to one embodiment of the present invention.

[0336] A Multi Access (MA) PDU session is a session that can simultaneously provide service to 3GPP access and non-3GPP access using a single PDU session.

[0337] Referring to Figure 10, the MA PDU session has a separate session tunnel for each access as one PDU session. One PDU session is established over a 3GPP access, and the other PDU session is established over a non-3GPP access.

[0338] An MA-PDU session has the following characteristics as a single session:

[0339] (i) one DNN;

[0340] (ii) one UPF anchor (UPF-A);

[0341] (iii) one PDU type (e.g., IPv6);

[0342] (iv) one session IP address;

[0343] (v) One SSC mode

[0344] (vi) One HPLMN S-NSSAI.

[0345] MA-PDU sessions enable multipath data links between UEs and UPF-A, and MA-PDU sessions can be established in either individual or combined manner.

[0346] The individual establishment of MA PDU sessions can be established through two separate PDU session establishment procedures. For example, after establishing an MA PDU session on a 3GPP access, the UE can perform a PDU session establishment procedure on a non-3GPP access to add the non-3GPP access to the MA PDU session established on the 3GPP access.

[0347] The MA PDU session can be established through a single MA PDU session establishment procedure. That is, a single PDU session creation request allows MA PDU sessions to be established simultaneously on 3GPP access and non-3GPP access.

[0348] After an MA-PDU session is established, SM (Session Management) signaling related to the MA PDU session can be transmitted and received through arbitrary access.

[0349]

[0350] Considering such MA PDU sessions, in the embodiment of FIG. 8, the 'PDU session connection permission information by access type' may be MA PDU session connection permission information by access type.

[0351] Accordingly, performing new PDU session establishment (S960) is preferably performed based on corresponding PDU session connection permission information depending on whether the MA PDU session is 3GPP, non-3GPP, or a combination of the 3GPP and non-3GPP.

[0352]

[0353] Meanwhile, in the embodiment of FIG. 9, the SSC (Session and Service Continuity) mode of the PDU session associated with the first NSSAI may be SSC mode 3.

[0354] In 3GPP, SSC modes 1, 2 and 3 can be defined as follows:

[0355] - With SSC mode 1, the network preserves the connectivity service provided to the UE. For the case of PDU Session of IPv4 or IPv6 or IPv4v6 type, the IP address is preserved.- With SSC mode 2, the network may release the connectivity service delivered to the UE and release the corresponding PDU Session(s). For the case of IPv4 or IPv6 or IPv4v6 type, the release of the PDU Session induces the release of IP address(es) that had been allocated to the UE.- With SSC mode 3, changes to the user plane can be visible to the UE, while the network ensures that the UE suffers no loss of connectivity. A connection through new PDU Session Anchor point is established before the previous connection is terminated in order to allow for better service continuity. For the case of IPv4 or IPv6 or IPv4v6 type, the IP address is not preserved in this mode when the PDU Session Anchor changes.

[0356] According to the SSC modes as specified above, if the SSC mode of the PDU session associated with the first NSSAI is SSC mode 3, a PDU session modification request message associated with the second NSSAI can be transmitted even before the PDU session associated with the first NSSAI is released.

[0357] On the other hand, the 3GPP Release 18 standard defines a partially allowed NSSAI. The existing allowed NSSAI refers to an NSSAI that notifies the network (AMF and / or SMF) that the network slicing service related to the NSSAI information is allowed for the NSSAI requested by the terminal in the registration area where the terminal is registered. In this case, the allowed NSSAI is applied on the PLMN or all TA lists of the registration area where the terminal is registered. On the other hand, the partially allowed NSSAI is applied on the PLMN or some TA lists of the registration area where the terminal is registered. Therefore, in the registered area, network slicing service associated with the partially allowed NSSAI (e.g., Partially Allowed NSSAI#1 - actually a specific S-NSSAI#1) is allowed in some TAs, but network slicing service associated with the partially allowed NSSAI (e.g., Partially Allowed NSSAI#1 - actually a specific S-NSSAI#1) is not allowed in other TAs. This partially allowed NSSAI information is updated through the Registration Procedure or the Generic UE Configuration Update Procedure.

[0358]

[0359] In the following, embodiments for processing a PDU session by considering the access type and embodiments for processing a PDU session without considering the access type are described in detail, when the PDU session is an MA PDU session and / or the NSSAI is a partially allowed NSSAI.

[0360]

[0361] <If access type is not considered>

[0362] Example 1a - PDU Session Establishment Procedure

[0363] Step 0) Partially allowed NSSAI and NoS (Network Slice Area of ​​Service) in 3GPP network have been newly changed. 3GPP network (AMF and / or SMF) will receive new / updated Partially Allowed NSSAI (e.g. Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) and NS-AoS (e.g. NS-AoS#3 (actually S-NSSAI#3 and NS-AoS#3 information)) information from NSSF.

[0364] Step 1) When the terminal has not yet received Partially Allowed NSSAI (and / or NS-AoS) information from the network, i.e., is unaware of unavailable or changed Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information)), it transmits a PDU Session Establishment Request message related to this Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1) to the network. At this time, the corresponding PDU Session is an MA PDU Session of SSC mode 1, 2, or 3.

[0365] Step 2) The network recognizes that the PDU Session Establishment request transmitted by the terminal is unavailable or changed, related to Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information)), and therefore cannot be performed. Therefore, the network responds with a PDU Session Establishment Reject message to the terminal. At this time, the PDU Session Establishment Reject message may include a BO timer with Partially Allowed NSSAI#1 and / or (new / updated) Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) and / or 5GSM cause value (new #wx "Partial NSSAI is not allowed" or "Network slice area of ​​service is not allowed") information.

[0366] Step 3) When a terminal receives a PDU Session Establishment Reject message from the network, if it has been provided with a BO timer with Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information), it starts the corresponding BO timer. At this time, it does not perform a PDU Session Establishment Request based on Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information) until the BO timer expires. If (new / updated) Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) is provided, the terminal replaces (updates) the existing Partially Allowed NSSAI#1 with Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information). Afterwards, the terminal performs a new PDU Session Establishment Request procedure to the network based on the replaced (updated) Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information).

[0367]

[0368] Example 1b - Establishing a PDU Session

[0369] Step 0) Partially Allowed NSSAI and NoS are newly changed in 3GPP network. 3GPP network (AMF and / or SMF) receives new / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) and NS-AoS (e.g., NS-AoS#3 (actually S-NSSAI#3 and NS-AoS#3 information)) information from NSSF.

[0370] Step 1) When the terminal has not yet received Partially Allowed NSSAI (and / or NS-AoS) information from the network, i.e., is unaware of unavailable or changed Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information)), it transmits a PDU Session Establishment Request message related to this Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1) to the network. At this time, the corresponding PDU Session is an MA PDU Session of SSC mode 1, 2, or 3.

[0371] Step 2) The network recognizes that the PDU Session Establishment request transmitted by the terminal is related to an unavailable or changed Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information)) and cannot be performed, so it responds with a PDU Session Establishment Reject message to the terminal. At this time, the PDU Session Establishment Reject message can be transmitted including BO timer with Partially Allowed NSSAI#1 and / or 5GSM cause value (new #wx "Partial NSSAI is not allowed" or "Network slice area of ​​service is not allowed") information.

[0372] Step 3) The network already has new / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) and NS-AoS (e.g., NS-AoS#3 (actually S-NSSAI#3 and NS-AoS#3 information)) information, and recognizes that the PDU Session Establishment request transmitted by the terminal in Step 2) is related to an unavailable or changed Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information)), so it can determine that the terminal is attempting to perform the PDU Session Establishment request procedure with incorrect information (e.g., Partially Allowed NSSAI#1). Therefore, after transmitting the PDU Session Establishment Reject message to the terminal in Step 2), the network immediately transmits a Configuration Update Command (Generic UE configuration update procedure) message to the terminal. At this time, the network transmits the newly changed / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) information.

[0373] Step 4) When a terminal receives a PDU Session Establishment Reject message from the network, if it has been provided with a BO timer with Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information), it starts the corresponding BO timer. At this time, it does not perform a PDU Session Establishment Request based on Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information) until the BO timer expires. When a UE receives a Configuration Update Command (Generic UE configuration update procedure) message from the network, if it is provided with a newly changed / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)), the UE replaces (updates) the existing Partially Allowed NSSAI#1 with Partially Allowed NSSAI#2, and then performs a new PDU Session Establishment Request procedure to the network based on the replaced (updated) Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information).

[0374]

[0375] Example 2a - PDU Session Modification Procedure

[0376] Step 0) Partially Allowed NSSAI and NoS are newly changed in 3GPP network. 3GPP network (AMF and / or SMF) receives new / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) and NS-AoS (e.g., NS-AoS#3 (actually S-NSSAI#3 and NS-AoS#3 information)) information from NSSF. Additionally, the UE has an existing PDU session associated with Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information)) that is unavailable or has been changed. In this case, the PDU session is an MA PDU session of SSC mode 1, 2, or 3.

[0377] Step 1) When the terminal has not yet received Partially Allowed NSSAI (and / or NS-AoS) information from the network, i.e., is unaware of the unavailable or changed Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information)), it transmits a PDU Session Modification Request message related to this Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1) to the network.

[0378] Step 2) The network recognizes that the PDU Session Modification request transmitted by the terminal is related to an unavailable or changed Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information)) and cannot be processed, so it responds to the terminal with a PDU Session Modification Reject message. At this time, the PDU Session Modification Reject message may include a BO timer with Partially Allowed NSSAI#1 and / or (new / updated) Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) and / or 5GSM cause value (new #wx "Partial NSSAI is not allowed" or "Network slice area of ​​service is not allowed") information.

[0379] Step 3) The network already has new / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) and NS-AoS (e.g., NS-AoS#3 (actually S-NSSAI#3 and NS-AoS#3 information)) information, and recognizes that the PDU Session Modification request transmitted by the terminal in Step 2) is related to an unavailable or changed Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information)), so it can determine that the terminal is trying to perform the PDU Session Modification request procedure with incorrect information (e.g., Partially Allowed NSSAI#1).

[0380] Step 4a) When a terminal receives a PDU Session Modification Reject message from the network, if it is provided with a BO timer with Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information), it starts the corresponding BO timer. At this time, the terminal does not perform a PDU Session Modification Request based on Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information) until the BO timer expires. In this situation, the terminal maintains the existing PDU Session (for Partially Allowed NSSAI#1) as is. That is, the terminal does not perform the PDU Session Modification Request procedure based on the additionally changed / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)).

[0381] Afterwards, when the existing PDU Session (for Partially Allowed NSSAI#1) is Released, if the terminal receives a new / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) from the network through a PDU Session Modification Reject message, the terminal can replace (update) the existing Partially Allowed NSSAI#1 with Partially Allowed NSSAI#2, and then perform a new PDU Session Establishment Request procedure to the network based on the replaced (updated) Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information).

[0382] Step 4b) At this time, if the PDU session is SSC mode 3 and an MA PDU session, it can operate as follows, differently from step 4a).

[0383] 1) If a previously established PDU session is established on both 3GPP access and non-3GPP access, and if the terminal is registered on both 3GPP access and non-3GPP access in the same PLMN, the terminal performs a new PDU Session Establishment Request procedure to the network based on the new / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) on the access from which the PDU session modification reject message was received. If the terminal is registered in 3GPP access and non-3GPP access in different PLMNs, the terminal first performs a PDU Session Establishment Request procedure based on the new / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) to the network on the access from which the PDU session modification reject message was received. Afterwards, the terminal performs a PDU Session Establishment Request procedure based on the new / updated Partially Allowed NSSAI on the other access to the network again.

[0384] 2) If the previously established PDU session is established on only one access (3GPP access or non-3GPP access), the terminal performs a new PDU Session Establishment Request procedure based on the new / updated Partially Allowed NSSAI to the network on that access.

[0385] If the above PDU session is a PDU session on only one access, the operation of step 4a) is performed as is on the corresponding access.

[0386]

[0387] Example 2b - PDU Session Modification Procedure

[0388] Step 0) Partially Allowed NSSAI and NoS are newly changed in 3GPP network. 3GPP network (AMF and / or SMF) receives new / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) and NS-AoS (e.g., NS-AoS#3 (actually S-NSSAI#3 and NS-AoS#3 information)) information from NSSF. Additionally, the UE has an existing PDU session associated with Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information)) that is unavailable or has been changed. In this case, the PDU session is an MA PDU session of SSC mode 1, 2, or 3.

[0389] Step 1) When the terminal has not yet received Partially Allowed NSSAI (and / or NS-AoS) information from the network, i.e., is unaware of the unavailable or changed Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information)), it transmits a PDU Session Modification Request message related to this Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1) to the network.

[0390] Step 2) The network recognizes that the PDU Session Modification request transmitted by the terminal is related to an unavailable or modified Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information)), and therefore cannot be processed, and responds to the terminal with a PDU Session Establishment Reject message. At this time, the PDU Session Modification Reject message may be transmitted including BO timer with Partially Allowed NSSAI#1 and / or 5GSM cause value (new #wx "Partial NSSAI is not allowed" or "Network slice area of ​​service is not allowed") information.

[0391] Step 3) The network already has new / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) and NS-AoS (e.g., NS-AoS#3 (actually S-NSSAI#3 and NS-AoS#3 information)) information, and recognizes that the PDU Session Modification request transmitted by the terminal in Step 2) is related to an unavailable or changed Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information)), so it can determine that the terminal is trying to perform the PDU Session Modification request procedure with incorrect information (e.g., Partially Allowed NSSAI#1). Therefore, after transmitting the PDU Session Modification Reject message to the terminal in Step 2), the network immediately transmits a Configuration Update Command (Generic UE configuration update procedure) message to the terminal. At this time, the network transmits the newly changed / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) information.

[0392] Step 4a) When a terminal receives a PDU Session Modification Reject message from the network, if it is provided with a BO timer with Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information), it starts the corresponding BO timer. At this time, the terminal does not perform a PDU Session Modification Request based on Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information) until the BO timer expires. In this situation, the terminal maintains the existing PDU Session (for Partially Allowed NSSAI#1) as is. That is, the terminal does not perform the PDU Session Modification Request procedure based on the additionally changed / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)).

[0393] Afterwards, when the existing PDU Session (for Partially Allowed NSSAI#1) is Released, if the terminal receives a new / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) from the network through a Configuration Update Command message, the terminal can replace (update) the existing Partially Allowed NSSAI#1 with Partially Allowed NSSAI#2, and then perform a new PDU Session Establishment Request procedure to the network based on the replaced (updated) Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information).

[0394] Step 4b) At this time, if the PDU session is SSC mode 3 and an MA PDU session, it can operate as follows, differently from step 4a).

[0395] 1) If a previously established PDU session is established on both 3GPP access and non-3GPP access, and if the terminal is registered on both 3GPP access and non-3GPP access in the same PLMN, the terminal first performs a new PDU Session Establishment Request procedure to the network based on the new / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) on the access from which the PDU session modification reject message was received. If the terminal is registered in 3GPP access and non-3GPP access in different PLMNs, the terminal first performs a PDU Session Establishment Request procedure based on the new / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) to the network on the access from which the PDU session modification reject message was received. Afterwards, the terminal performs a PDU Session Establishment Request procedure based on the new / updated Partially Allowed NSSAI on the other access to the network again.

[0396] 2) If the previously established PDU session is established on only one access (3GPP access or non-3GPP access), the terminal performs a new PDU Session Establishment Request procedure based on the new / updated Partially Allowed NSSAI to the network on that access.

[0397] If the above PDU session is a PDU session on only one access, the operation of step 4a) is performed as is on the corresponding access.

[0398]

[0399] <Considering access type>

[0400] Example 3a - PDU Session Establishment Procedure

[0401] Step 0) Partially Allowed NSSAI and NoS are newly changed in the 3GPP network. The 3GPP network (AMF and / or SMF) receives the newly changed / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) and NS-AoS (e.g., NS-AoS#3 (actually S-NSSAI#3 and NS-AoS#3 information)) information from the NSSF. At this time, the terminal also receives MA PDU Session connection permission information by Access type from the network. This MA PDU Session connection permission information by Access type is provided and updated by the network to the terminal through the Registration Procedure or the Generic UE Configuration Update Procedure. At this time, the provided updated information may be provided together with Partially Allowed NSSAI and access type information, and the access type information may be included in the NAS message and provided in the form of 3GPP access (only), non-3GPP access (only), 3GPP access and non-3GPP access, both 3GPP access and non-3GPP access, etc.

[0402] Step 1) When the terminal has not yet received Partially Allowed NSSAI (and / or NS-AoS) information from the network, i.e., is unaware of the Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information)) that is unavailable or changed, the terminal transmits a PDU Session Establishment Request message related to this Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1) to the network. At this time, based on the old access type information, the terminal transmits a PDU Session Establishment Request message related to the Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1) to the network on an access for which MA PDU Session connection is allowed. At this time, the corresponding PDU Session is an MA PDU Session of SSC mode 1, 2, or 3.

[0403] Step 2) The network recognizes that the PDU Session Establishment request transmitted by the terminal is unavailable or changed, related to Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information)), and therefore cannot be performed. Therefore, the network responds with a PDU Session Establishment Reject message to the terminal. At this time, the PDU Session Establishment Reject message may include a BO timer with Partially Allowed NSSAI#1 and / or (new / updated) Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) and / or 5GSM cause value (new #wx "Partial NSSAI is not allowed" or "Network slice area of ​​service is not allowed") information. At this time, MA PDU Session connection permission information by Access type may also be transmitted together with (new / updated) Partially Allowed NSSAI information. This updated MA PDU Session connection permission information by Access type may be provided in the form of NAS messages such as 3GPP access (only), non-3GPP access (only), 3GPP access and non-3GPP access, and both 3GPP access and non-3GPP access.

[0404] Step 3) When a terminal receives a PDU Session Establishment Reject message from the network, if it has been provided with a BO timer with Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information), it starts the corresponding BO timer. At this time, it does not perform a PDU Session Establishment Request based on Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information) until the BO timer expires. If (new / updated) Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) is provided, the terminal replaces (updates) the existing Partially Allowed NSSAI#1 with Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information). Afterwards, the terminal performs a new PDU Session Establishment Request procedure to the network based on the replaced (updated) Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information).At this time, based on the newly updated access type information along with Partially Allowed NSSAI#2, a PDU Session Establishment Request message related to Partially Allowed NSSAI#2 (e.g., actually S-NSSAI#2 and Partial tracking area identity list#2 information) is transmitted to the network as an access for which MA PDU Session connection is allowed.

[0405]

[0406] Example 3b - PDU Session Establishment Procedure

[0407] Step 0) Partially Allowed NSSAI and NoS are newly changed in the 3GPP network. The 3GPP network (AMF and / or SMF) receives the newly changed / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) and NS-AoS (e.g., NS-AoS#3 (actually S-NSSAI#3 and NS-AoS#3 information)) information from the NSSF. At this time, the terminal also receives MA PDU Session connection permission information by Access type from the network. This MA PDU Session connection permission information by Access type is provided and updated by the network to the terminal through the Registration Procedure or the Generic UE Configuration Update Procedure. At this time, the provided updated information may be provided together with Partially Allowed NSSAI and access type information, and the access type information may be included in the NAS message and provided in the form of 3GPP access (only), non-3GPP access (only), 3GPP access and non-3GPP access, both 3GPP access and non-3GPP access, etc.

[0408] Step 1) When the terminal has not yet received Partially Allowed NSSAI (and / or NS-AoS) information from the network, i.e., is unaware of the Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information)) that is unavailable or changed, the terminal transmits a PDU Session Establishment Request message related to this Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1) to the network. At this time, based on the old access type information, the terminal transmits a PDU Session Establishment Request message related to the Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1) to the network on an access for which MA PDU Session connection is allowed. At this time, the corresponding PDU Session is an MA PDU Session of SSC mode 1, 2, or 3.

[0409] Step 2) The network recognizes that the PDU Session Establishment request transmitted by the terminal is related to an unavailable or changed Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information)) and cannot be performed, so it responds with a PDU Session Establishment Reject message to the terminal. At this time, the PDU Session Establishment Reject message can be transmitted including BO timer with Partially Allowed NSSAI#1 and / or 5GSM cause value (new #wx "Partial NSSAI is not allowed" or "Network slice area of ​​service is not allowed") information.

[0410] Step 3) The network already has new / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) and NS-AoS (e.g., NS-AoS#3 (actually S-NSSAI#3 and NS-AoS#3 information)) information, and recognizes that the PDU Session Establishment request transmitted by the terminal in Step 2) is related to an unavailable or changed Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information)), so it can determine that the terminal is attempting to perform the PDU Session Establishment request procedure with incorrect information (e.g., Partially Allowed NSSAI#1). Therefore, after transmitting the PDU Session Establishment Reject message to the terminal in Step 2), the Configuration Update Command (Generic UE configuration update procedure) message is immediately transmitted to the terminal. At this time, the network transmits the newly changed / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) information. At this time, along with the (new / updated) Partially Allowed NSSAI information, MA PDU Session connection permission information by Access type may also be transmitted.This updated Access type-specific MA PDU Session connection permission information can be included in NAS messages in the form of 3GPP access (only), non-3GPP access (only), 3GPP access and non-3GPP access, both 3GPP access and non-3GPP access, etc.

[0411] Step 4) When a terminal receives a PDU Session Establishment Reject message from the network, if it has been provided with a BO timer with Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information), it starts the corresponding BO timer. At this time, it does not perform a PDU Session Establishment Request based on Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information) until the BO timer expires. When a UE receives a Configuration Update Command (Generic UE configuration update procedure) message from the network, if it is provided with a newly changed / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)), the UE replaces (updates) the existing Partially Allowed NSSAI#1 with Partially Allowed NSSAI#2, and then performs a new PDU Session Establishment Request procedure to the network based on the replaced (updated) Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information).At this time, based on the newly updated access type information along with Partially Allowed NSSAI#2, a PDU Session Establishment Request message related to Partially Allowed NSSAI#2 (e.g., actually S-NSSAI#2 and Partial tracking area identity list#2 information) is transmitted to the network as an access for which MA PDU Session connection is allowed.

[0412]

[0413] Example 4a - PDU Session Modification Procedure

[0414] Step 0) Partially Allowed NSSAI and NoS are newly changed in the 3GPP network. The 3GPP network (AMF and / or SMF) receives the newly changed / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) and NS-AoS (e.g., NS-AoS#3 (actually S-NSSAI#3 and NS-AoS#3 information)) information from the NSSF. At this time, the terminal also receives MA PDU Session connection permission information by Access type from the network. This MA PDU Session connection permission information by Access type is provided and updated by the network to the terminal through the Registration Procedure or the Generic UE Configuration Update Procedure. At this time, the provided updated information may be provided together with Partially Allowed NSSAI and access type information, and the access type information may be included in the NAS message and provided in the form of 3GPP access (only), non-3GPP access (only), 3GPP access and non-3GPP access, both 3GPP access and non-3GPP access, etc.Additionally, the UE has an existing PDU session associated with Partially Allowed NSSAI#1 that is unavailable or has been changed (e.g., Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information)).

[0415] Step 1) When the terminal has not yet received Partially Allowed NSSAI (and / or NS-AoS) information from the network, i.e., is unaware of the unavailable or changed Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information)), it transmits a PDU Session Modification Request message related to this Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1) to the network. At this time, based on the old access type information, it transmits a PDU Session Modification Request message related to the Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1) to the network on an access for which MA PDU Session connection is allowed. At this time, the corresponding PDU Session is an MA PDU Session of SSC mode 1, 2, or 3.

[0416]

[0417] Step 2) The network recognizes that the PDU Session Modification request transmitted by the terminal is related to an unavailable or changed Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information)) and cannot be processed, so it responds to the terminal with a PDU Session Modification Reject message. At this time, the PDU Session Modification Reject message may include a BO timer with Partially Allowed NSSAI#1 and / or (new / updated) Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) and / or 5GSM cause value (new #wx "Partial NSSAI is not allowed" or "Network slice area of ​​service is not allowed") information. At this time, MA PDU Session connection permission information by Access type may also be transmitted together with (new / updated) Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2) information. This updated MA PDU Session connection permission information by Access type may be provided in the form of 3GPP access (only), non-3GPP access (only), 3GPP access and non-3GPP access, both 3GPP access and non-3GPP access, etc. in the NAS message.

[0418] Step 3) The network already has new / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) and NS-AoS (e.g., NS-AoS#3 (actually S-NSSAI#3 and NS-AoS#3 information)) information, and recognizes that the PDU Session Modification request transmitted by the terminal in Step 2) is related to an unavailable or changed Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information)), so it can determine that the terminal is trying to perform the PDU Session Modification request procedure with incorrect information (e.g., Partially Allowed NSSAI#1).

[0419] Step 4a) When a terminal receives a PDU Session Modification Reject message from the network, if it is provided with a BO timer with Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information), it starts the corresponding BO timer. At this time, the terminal does not perform a PDU Session Modification Request based on Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information) until the BO timer expires. In this situation, the terminal maintains the existing PDU Session (for Partially Allowed NSSAI#1) as is. That is, the terminal does not perform the PDU Session Modification Request procedure based on the additionally changed / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)).

[0420] Afterwards, when the existing PDU Session (for Partially Allowed NSSAI#1) is Released, if the terminal receives a new / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) from the network through a PDU Session Modification Reject message, the terminal can replace (update) the existing Partially Allowed NSSAI#1 with Partially Allowed NSSAI#2, and then perform a new PDU Session Establishment Request procedure to the network based on the replaced (updated) Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information). At this time, based on the newly updated access type information along with Partially Allowed NSSAI#2, a PDU Session Establishment Request message related to Partially Allowed NSSAI#2 (e.g., actually S-NSSAI#2 and Partial tracking area identity list#2 information) is transmitted to the network as an access for which MA PDU Session connection is allowed.

[0421] Step 4b) At this time, if the PDU session is SSC mode 3 and an MA PDU session, it can operate as follows, differently from step 4a).

[0422] 1) If a previously established PDU session is established on both 3GPP access and non-3GPP access, and if the terminal is registered on both 3GPP access and non-3GPP access in the same PLMN, the terminal performs a new PDU Session Establishment Request procedure to the network based on the new / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) on the access from which the PDU session modification reject message was received. If the terminal is registered in 3GPP access and non-3GPP access in different PLMNs, the terminal first performs a new PDU Session Establishment Request procedure to the network based on the new / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) on the access from which the PDU session modification reject message was received. Afterwards, the terminal performs a new PDU Session Establishment Request procedure to the network based on the new / updated Partially Allowed NSSAI and access type information on the other access.

[0423] 2) If the previously established PDU session is established on only one access (3GPP access or non-3GPP access), the terminal performs a new PDU Session Establishment Request procedure to the network based on the newly changed / updated Partially Allowed NSSAI and access type information.

[0424] If the above PDU session is a PDU session on only one access, the operation of step 4a) is performed as is on the corresponding access.

[0425]

[0426] Example 4b - PDU Session Modification Procedure

[0427] Step 0) Partially Allowed NSSAI and NoS are newly changed in the 3GPP network. The 3GPP network (AMF and / or SMF) receives the newly changed / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) and NS-AoS (e.g., NS-AoS#3 (actually S-NSSAI#3 and NS-AoS#3 information)) information from the NSSF. At this time, the terminal also receives MA PDU Session connection permission information by Access type from the network. This MA PDU Session connection permission information by Access type is provided and updated by the network to the terminal through the Registration Procedure or the Generic UE Configuration Update Procedure. At this time, the provided updated information may be provided together with Partially Allowed NSSAI and access type information, and the access type information may be included in the NAS message and provided in the form of 3GPP access (only), non-3GPP access (only), 3GPP access and non-3GPP access, both 3GPP access and non-3GPP access, etc.Additionally, the UE has an existing PDU session associated with Partially Allowed NSSAI#1 that is unavailable or has been changed (e.g., Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information)).

[0428] Step 1) When the terminal has not yet received Partially Allowed NSSAI (and / or NS-AoS) information from the network, i.e., is unaware of the unavailable or changed Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information)), it transmits a PDU Session Modification Request message related to this Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1) to the network. At this time, based on the old access type information, it transmits a PDU Session Modification Request message related to the Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1) to the network on an access for which MA PDU Session connection is allowed. At this time, the corresponding PDU Session is an MA PDU Session of SSC mode 1, 2, or 3.

[0429] Step 2) The network recognizes that the PDU Session Modification request transmitted by the terminal is related to an unavailable or modified Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information)), and therefore cannot be processed, and responds to the terminal with a PDU Session Establishment Reject message. At this time, the PDU Session Modification Reject message may be transmitted including BO timer with Partially Allowed NSSAI#1 and / or 5GSM cause value (new #wx "Partial NSSAI is not allowed" or "Network slice area of ​​service is not allowed") information.

[0430] Step 3) The network already has new / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) and NS-AoS (e.g., NS-AoS#3 (actually S-NSSAI#3 and NS-AoS#3 information)) information, and recognizes that the PDU Session Modification request transmitted by the terminal in Step 2) is related to an unavailable or changed Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information)), so it can determine that the terminal is attempting to perform the PDU Session Establishment request procedure with incorrect information (e.g., Partially Allowed NSSAI#1). Therefore, after transmitting the PDU Session Modification Reject message to the terminal in Step 2), the network immediately transmits a Configuration Update Command (Generic UE configuration update procedure) message to the terminal. At this time, the network transmits the newly changed / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) information.At this time, MA PDU Session connection permission information by Access type may also be transmitted together with (new / updated) Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2) information. This updated MA PDU Session connection permission information by Access type may be provided in the form of 3GPP access (only), non-3GPP access (only), 3GPP access and non-3GPP access, both 3GPP access and non-3GPP access, etc. in the NAS message.

[0431] Step 4a) When a terminal receives a PDU Session Modification Reject message from the network, if it is provided with a BO timer with Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information), it starts the corresponding BO timer. At this time, the terminal does not perform a PDU Session Modification Request based on Partially Allowed NSSAI#1 (actually S-NSSAI#1 and Partial tracking area identity list#1 information) until the BO timer expires. In this situation, the terminal maintains the existing PDU Session (for Partially Allowed NSSAI#1) as is. That is, the terminal does not perform the PDU Session Modification Request procedure based on the additionally changed / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)).

[0432] Afterwards, when the existing PDU Session (for Partially Allowed NSSAI#1) is Released, if the terminal receives a new / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) from the network through a Configuration Update Command message, the terminal can replace (update) the existing Partially Allowed NSSAI#1 with Partially Allowed NSSAI#2, and then perform a new PDU Session Establishment Request procedure to the network based on the replaced (updated) Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information). At this time, based on the newly updated access type information along with Partially Allowed NSSAI#2, a PDU Session Establishment Request message related to Partially Allowed NSSAI#2 (e.g., actually S-NSSAI#2 and Partial tracking area identity list#2 information) is transmitted to the network as an access for which MA PDU Session connection is allowed.

[0433] Step 4b) At this time, if the PDU session is SSC mode 3 and an MA PDU session, it can operate as follows, differently from step 4a).

[0434] 1) If a previously established PDU session is established on both 3GPP access and non-3GPP access, and if the terminal is registered on both 3GPP access and non-3GPP access in the same PLMN, the terminal performs a new PDU Session Establishment Request procedure to the network based on the new / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) on the access from which the PDU session modification reject message was received. If the terminal is registered in 3GPP access and non-3GPP access in different PLMNs, the terminal first performs a new PDU Session Establishment Request procedure to the network based on the new / updated Partially Allowed NSSAI (e.g., Partially Allowed NSSAI#2 (actually S-NSSAI#2 and Partial tracking area identity list#2 information)) on the access from which the PDU session modification reject message was received. Afterwards, the terminal performs a new PDU Session Establishment Request procedure to the network based on the new / updated Partially Allowed NSSAI and access type information on the other access.

[0435] 2) If the previously established PDU session is established on only one access (3GPP access or non-3GPP access), the terminal performs a new PDU Session Establishment Request procedure to the network based on the newly changed / updated Partially Allowed NSSAI and access type information.

[0436] If the above PDU session is a PDU session on only one access, the operation of step 4a) is performed as is on the corresponding access.

[0437]

[0438] Figure 11 shows a block diagram of a processor in which the disclosure of this specification is implemented.

[0439] As can be seen from FIG. 11, the processor (1020) implementing the disclosure of the present specification may include multiple circuits to implement the proposed functions, procedures, and / or methods described herein. For example, the processor (1020) may include a first circuit (1020-1), a second circuit (1020-2), and a third circuit (1020-3). Furthermore, although not shown, the processor (1020) may include more circuits. Each circuit may include multiple transistors.

[0440] The above processor (1020) may be called an ASIC (application-specific integrated circuit) or AP (application processor) and may include at least one of a DSP (digital signal processor), a CPU (central processing unit), and a GPU (graphics processing unit).

[0441] The above processor can be mounted on a UE.

[0442] Figure 12 illustrates a device according to one embodiment of the present specification.

[0443] Referring to FIG. 12, the wireless communication system may include a first device (100a) and a second device (100b).

[0444] The first device (100a) may be a UE described in the disclosure of this specification. Alternatively, the first device (100a) may be a base station, a network node, a transmitting UE, a receiving UE, a wireless device, a wireless communication device, a vehicle, a vehicle equipped with an autonomous driving function, a connected car, a drone (Unmanned Aerial Vehicle, UAV), an AI (Artificial Intelligence) module, a robot, an AR (Augmented Reality) device, a VR (Virtual Reality) device, an MR (Mixed Reality) device, a hologram device, a public safety device, an MTC device, an IoT device, a medical device, a fintech device (or a financial device), a security device, a climate / environmental device, a device related to 5G services, or any other device related to the field of the 4th Industrial Revolution.

[0445] The second device (100b) may be a network node (e.g., AMF or MME) described in the disclosure of this specification. Alternatively, the second device (100b) may be a base station, a network node, a transmitting UE, a receiving UE, a wireless device, a wireless communication device, a vehicle, a vehicle equipped with an autonomous driving function, a connected car, a drone (Unmanned Aerial Vehicle, UAV), an AI (Artificial Intelligence) module, a robot, an AR (Augmented Reality) device, a VR (Virtual Reality) device, an MR (Mixed Reality) device, a hologram device, a public safety device, an MTC device, an IoT device, a medical device, a fintech device (or a financial device), a security device, a climate / environmental device, a device related to 5G services, or any other device related to the field of the 4th Industrial Revolution.

[0446] For example, the UE (100) may include a mobile phone, a smart phone, a laptop computer, a digital broadcasting UE, a personal digital assistant (PDA), a portable multimedia player (PMP), a navigation device, a slate PC, a tablet PC, an ultrabook, a wearable device (e.g., a smartwatch, a smart glass, a head mounted display (HMD)), etc. For example, the HMD may be a display device worn on the head. For example, the HMD may be used to implement VR, AR, or MR.

[0447] For example, a drone may be an unmanned aircraft that flies by wireless control signals. For example, a VR device may include a device that implements virtual world objects or backgrounds. For example, an AR device may include a device that implements virtual world objects or backgrounds by connecting them to real world objects or backgrounds. For example, an MR device may include a device that implements virtual world objects or backgrounds by merging them with real world objects or backgrounds. For example, a holographic device may include a device that utilizes holography, a light interference phenomenon that occurs when two laser beams meet, to record and reproduce three-dimensional information to implement a 360-degree stereoscopic image. For example, a public safety device may include a video relay device or a wearable imaging device on the user's body. For example, MTC devices and IoT devices may be devices that do not require direct human intervention or operation. For example, MTC devices and IoT devices may include smart meters, bending machines, thermometers, smart light bulbs, door locks, or various sensors. For example, a medical device may be a device used for the purpose of diagnosing, treating, alleviating, managing, or preventing a disease. For example, a medical device may be a device used for the purpose of diagnosing, treating, alleviating, or correcting an injury or disability. For example, a medical device may be a device used for the purpose of examining, replacing, or modifying a structure or function. For example, a medical device may be a device used for the purpose of regulating pregnancy. For example, a medical device may include a diagnostic device, a surgical device, an (in vitro) diagnostic device, a hearing aid, or a device for a procedure. For example, a security device may be a device installed to prevent potential risks and maintain safety. For example, a security device may be a camera, CCTV, a recorder, or a black box.For example, a fintech device may be a device capable of providing financial services, such as mobile payments. For example, a fintech device may include a payment device or a point of sale (POS). For example, a climate / environmental device may include a device that monitors or predicts the climate / environment.

[0448] The first device (100a) may include at least one processor, such as a processor (1020a), at least one memory, such as a memory (1010a), and at least one transceiver, such as a transceiver (1031a). The processor (1020a) may perform the functions, procedures, and / or methods described above. The processor (1020a) may perform one or more protocols. For example, the processor (1020a) may perform one or more layers of a wireless interface protocol. The memory (1010a) may be connected to the processor (1020a) and may store various types of information and / or commands. The transceiver (1031a) may be connected to the processor (1020a) and may be controlled to transmit and receive wireless signals.

[0449] The second device (100b) may include at least one processor, such as a processor (1020b), at least one memory device, such as a memory (1010b), and at least one transceiver, such as a transceiver (1031b). The processor (1020b) may perform the functions, procedures, and / or methods described above. The processor (1020b) may implement one or more protocols. For example, the processor (1020b) may implement one or more layers of a wireless interface protocol. The memory (1010b) may be connected to the processor (1020b) and may store various types of information and / or commands. The transceiver (1031b) may be connected to the processor (1020b) and may be controlled to transmit and receive wireless signals.

[0450] The memory (1010a) and / or the memory (1010b) may be connected internally or externally to the processor (1020a) and / or the processor (1020b), or may be connected to another processor via various technologies such as a wired or wireless connection.

[0451] The first device (100a) and / or the second device (100b) may have one or more antennas. For example, the antenna (1036a) and / or the antenna (1036b) may be configured to transmit and receive wireless signals.

[0452] FIG. 13 illustrates a block diagram of a network node according to one embodiment of the present specification.

[0453] In particular, FIG. 13 is a drawing that illustrates in detail a case where a base station is divided into a central unit (CU) and a distributed unit (DU).

[0454] Referring to FIG. 13, the base stations (W20, W30) may be connected to the core network (W10), and the base station (W30) may be connected to the neighboring base station (W20). For example, the interface between the base stations (W20, W30) and the core network (W10) may be referred to as NG, and the interface between the base station (W30) and the neighboring base station (W20) may be referred to as Xn.

[0455] The base station (W30) can be divided into a CU (W32) and DUs (W34, W36). That is, the base station (W30) can be operated hierarchically separated. The CU (W32) can be connected to one or more DUs (W34, W36), and for example, the interface between the CU (W32) and the DUs (W34, W36) can be referred to as F1. The CU (W32) can perform functions of upper layers of the base station, and the DUs (W34, W36) can perform functions of lower layers of the base station. For example, the CU (W32) may be a logical node hosting radio resource control (RRC), service data adaptation protocol (SDAP), and packet data convergence protocol (PDCP) layers of a base station (e.g., gNB), and the DUs (W34, W36) may be logical nodes hosting radio link control (RLC), media access control (MAC), and physical (PHY) layers of the base station. Alternatively, the CU (W32) may be a logical node hosting RRC and PDCP layers of a base station (e.g., en-gNB).

[0456] The operation of DU (W34, W36) can be partially controlled by CU (W32). One DU (W34, W36) can support more than one cell. One cell can be supported by only one DU (W34, W36). One DU (W34, W36) can be connected to one CU (W32), and by suitable implementation, one DU (W34, W36) can also be connected to multiple CUs.

[0457] Fig. 14 is a block diagram showing the configuration of a terminal according to one embodiment of the present specification.

[0458] In particular, the terminal, i.e., UE (100) illustrated in FIG. 14 is a drawing that illustrates the first device of FIG. 12 in more detail.

[0459] The UE (100) includes a memory (1010), a processor (1020), a transceiver (1031), a power management module (1091), a battery (1092), a display (1041), an input unit (1053), a speaker (1042), a microphone (1052), a subscriber identification module (SIM) card, and one or more antennas.

[0460] The processor (1020) may be configured to implement the proposed functions, procedures and / or methods described herein. Layers of a wireless interface protocol may be implemented in the processor (1020). The processor (1020) may include an application-specific integrated circuit (ASIC), other chipsets, logic circuits and / or data processing devices. The processor (1020) may be an application processor (AP). The processor (1020) may include at least one of a digital signal processor (DSP), a central processing unit (CPU), a graphics processing unit (GPU), and a modem (modulator and demodulator). Examples of the processor (1020) may be a SNAPDRAGON™ series processor manufactured by Qualcomm®, an EXYNOSTM series processor manufactured by Samsung®, an A series processor manufactured by Apple®, a HELIO™ series processor manufactured by MediaTek®, an ATOM™ series processor manufactured by INTEL®, or a corresponding next-generation processor.

[0461] The power management module (1091) manages power to the processor (1020) and / or the transceiver (1031). The battery (1092) supplies power to the power management module (1091). The display (1041) outputs the results processed by the processor (1020). The input unit (1053) receives input to be used by the processor (1020). The input unit (1053) can be displayed on the display (1041). A SIM card is an integrated circuit used to securely store an international mobile subscriber identity (IMSI) and its associated keys, which are used to identify and authenticate subscribers in mobile devices such as mobile phones and computers. Contact information can also be stored on many SIM cards.

[0462] The memory (1010) is operably coupled to the processor (1020) and stores various information for operating the processor (610). The memory (1010) may include read-only memory (ROM), random access memory (RAM), flash memory, memory cards, storage media, and / or other storage devices. When the embodiment is implemented in software, the techniques described herein may be implemented as modules (e.g., procedures, functions, etc.) that perform the functions described herein. The modules may be stored in the memory (1010) and executed by the processor (1020). The memory (1010) may be implemented within the processor (1020). Alternatively, the memory (1010) may be implemented external to the processor (1020) and communicatively connected to the processor (1020) via various means known in the art.

[0463] The transceiver (1031) is operably coupled to the processor (1020) and transmits and / or receives a radio signal. The transceiver (1031) includes a transmitter and a receiver. The transceiver (1031) may include a baseband circuit for processing a radio frequency signal. The transceiver controls one or more antennas to transmit and / or receive a radio signal. The processor (1020) transmits command information to the transceiver (1031) to initiate communication, for example, to transmit a radio signal constituting voice communication data. The antenna functions to transmit and receive radio signals. Upon receiving a radio signal, the transceiver (1031) may transmit the signal for processing by the processor (1020) and convert the signal to baseband. The processed signal may be converted into audible or readable information output through the speaker (1042).

[0464] The speaker (1042) outputs sound-related results processed by the processor (1020). The microphone (1052) receives sound-related input to be used by the processor (1020).

[0465] A user inputs command information, such as a phone number, for example, by pressing (or touching) a button on an input unit (1053) or by voice activation using a microphone (1052). The processor (1020) receives this command information and processes it to perform an appropriate function, such as dialing a phone number. Operational data can be extracted from a SIM card or memory (1010). In addition, the processor (1020) can display command information or operation information on a display (1041) for the user's recognition and convenience.

[0466] FIG. 15 is a block diagram showing in detail the transmitter / receiver of the first device illustrated in FIG. 12 or the transmitter / receiver unit of the device illustrated in FIG. 14.

[0467] Referring to FIG. 15, the transceiver (1031) includes a transmitter (1031-1) and a receiver (1031-2). The transmitter (1031-1) includes a Discrete Fourier Transform (DFT) unit (1031-11), a subcarrier mapper (1031-12), an IFFT unit (1031-13), a CP insertion unit (1031-14), and a wireless transmitter (1031-15). The transmitter (1031-1) may further include a modulator. In addition, for example, the transmitter may further include a scramble unit (not shown), a modulation mapper (not shown), a layer mapper (not shown), and a layer permutator (not shown), which may be arranged before the DFT unit (1031-11). That is, in order to prevent an increase in PAPR (peak-to-average power ratio), the transmitter (1031-1) first passes the information through a DFT (1031-11) before mapping the signal to a subcarrier. The signal spread (or precoded in the same sense) by the DFT unit (1031-11) is mapped to a subcarrier through a subcarrier mapper (1031-12) and then passes through an IFFT (Inverse Fast Fourier Transform) unit (1031-13) to be converted into a signal on the time axis.

[0468] The DFT unit (1031-11) performs DFT on the input symbols and outputs complex-valued symbols. For example, if Ntx symbols are input (where Ntx is a natural number), the DFT size is Ntx. The DFT unit (1031-11) may be called a transform precoder. The subcarrier mapper (1031-12) maps the complex symbols to each subcarrier in the frequency domain. The complex symbols may be mapped to resource elements corresponding to resource blocks allocated for data transmission. The subcarrier mapper (1031-12) may be called a resource element mapper. The IFFT unit (1031-13) performs IFFT on the input symbols and outputs a baseband signal for data, which is a time-domain signal. The CP insertion unit (1031-14) copies a portion of the rear portion of the baseband signal for data and inserts it into the front portion of the baseband signal for data. CP insertion prevents ISI (Inter-Symbol Interference) and ICI (Inter-Carrier Interference), thereby maintaining orthogonality even in multipath channels.

[0469] On the other hand, the receiver (1031-2) includes a wireless reception unit (1031-21), a CP removal unit (1031-22), an FFT unit (1031-23), and an equalization unit (1031-24). The wireless reception unit (1031-21), the CP removal unit (1031-22), and the FFT unit (1031-23) of the receiver (1031-2) perform the inverse functions of the wireless transmission unit (1031-15), the CP insertion unit (1031-14), and the IFF unit (1031-13) of the transmitter (1031-1). The receiver (1031-2) may further include a demodulator.

[0470] FIG. 16 illustrates another wireless communication system applicable to the disclosure of this specification.

[0471] The various descriptions, functions, procedures, proposals, methods and / or operational flowcharts of the disclosure of this specification can be applied to various fields requiring wireless communication / connection (e.g., 5G) between devices.

[0472] Referring to FIG. 16, a communication system (1) applicable to the disclosure of the present specification includes a wireless device, a base station, and a network. Here, the wireless device refers to a device that performs communication using a wireless access technology (e.g., 5G NR (New RAT), LTE (Long Term Evolution)) and may be referred to as a communication / wireless / 5G device. Although not limited thereto, the wireless device may include a robot (100a), a vehicle (100b-1, 100b-2), an XR (eXtended Reality) device (100c), a hand-held device (100d), a home appliance (100e), an IoT (Internet of Things) device (100f), and an AI device / server (400). For example, the vehicle may include a vehicle equipped with a wireless communication function, an autonomous vehicle, a vehicle capable of performing vehicle-to-vehicle communication, etc. Here, the vehicle may include an Unmanned Aerial Vehicle (UAV) (e.g., a drone). XR devices include AR (Augmented Reality) / VR (Virtual Reality) / MR (Mixed Reality) devices, and can be implemented in the form of HMD (Head-Mounted Device), HUD (Head-Up Display) installed in a vehicle, television, smartphone, computer, wearable device, home appliance, digital signage, vehicle, robot, etc. Mobile devices can include smartphone, smart pad, wearable device (e.g., smart watch, smart glass), computer (e.g., laptop, etc.), etc. Home appliances can include TV, refrigerator, washing machine, etc. IoT devices can include sensors, smart meters, etc. For example, base stations and networks can also be implemented as wireless devices, and a specific wireless device (200a) can act as a base station / network node to other wireless devices.

[0473] Wireless devices (100a to 100f) can be connected to a network (300) via a base station (200). Artificial Intelligence (AI) technology can be applied to the wireless devices (100a to 100f), and the wireless devices (100a to 100f) can be connected to an AI server (400) via the network (300). The network (300) can be configured using a 3G network, a 4G (e.g., LTE) network, a 5G (e.g., NR) network, etc. The wireless devices (100a to 100f) can communicate with each other via the base station (200) / network (300), but can also communicate directly (e.g., sidelink communication) without going through the base station / network. For example, vehicles (100b-1, 100b-2) can communicate directly (e.g., V2V (Vehicle to Vehicle) / V2X (Vehicle to Everything) communication). In addition, IoT devices (e.g., sensors) can communicate directly with other IoT devices (e.g., sensors) or other wireless devices (100a to 100f).

[0474] Wireless communication / connection (150a, 150b, 150c) can be established between wireless devices (100a~100f) / base stations (200), and base stations (200) / base stations (200). Here, wireless communication / connection can be achieved through various wireless access technologies (e.g., 5G NR) such as uplink / downlink communication (150a), sidelink communication (150b) (or D2D communication), and communication between base stations (150c) (e.g., relay, IAB (Integrated Access Backhaul). Through wireless communication / connection (150a, 150b, 150c), wireless devices and base stations / wireless devices, and base stations and base stations can transmit / receive wireless signals to each other. For example, wireless communication / connection (150a, 150b, 150c) can transmit / receive signals through various physical channels. To this end, at least some of various configuration information setting processes for transmitting / receiving wireless signals, various signal processing processes (e.g., channel encoding / decoding, modulation / demodulation, resource mapping / demapping, etc.), and resource allocation processes can be performed based on various proposals of the disclosure of the present specification.

[0475] Although the preferred embodiments have been described above by way of example, the disclosure of this specification is not limited to these specific embodiments, and may be modified, changed, or improved in various forms within the scope described in the spirit and claims of this specification.

[0476] In the exemplary system described above, the methods are described based on a flowchart as a series of steps or blocks. However, the order of the steps described is not limited, and some steps may occur in a different order or simultaneously with other steps described above. Furthermore, those skilled in the art will understand that the steps depicted in the flowchart are not exclusive, and other steps may be included, or one or more steps in the flowchart may be deleted without affecting the scope of the invention.

[0477] The claims set forth in this specification may be combined in various ways. For example, the technical features of the method claims of this specification may be combined and implemented as a device, and the technical features of the device claims of this specification may be combined and implemented as a method. Furthermore, the technical features of the method claims and the technical features of the device claims of this specification may be combined and implemented as a device, and the technical features of the method claims and the technical features of the device claims of this specification may be combined and implemented as a method.

Claims

1. In a method for operating a terminal in a wireless communication system, Establish a PDU (protocol data unit) session associated with the first NSSAI (network slice selection assistance information); Transmitting a PDU session request message associated with the first NSSAI to the network; In response to the transmitted PDU session request message, a PDU session reject message is received from the network; Determine whether PDU session connection permission information by access type has been received from the above network; and A method of operating a terminal, comprising: when receiving PDU session connection permission information by access type, performing a new PDU session request according to the PDU session connection permission information by access type.

2. In paragraph 1, A terminal operation method in which the PDU session connection permission information for each access type is received through the PDU session rejection message.

3. In paragraph 2, The above PDU session rejection message is, Additionally, a second NSSAI, which is a different NSSAI from the first NSSAI, is included. Performing the above new PDU session establishment is as follows: A method of operating a terminal, comprising performing establishment or modification of a second PDU session associated with the second NSSAI.

4. In paragraph 1, A method of operating a terminal in which the PDU session connection permission information for each access type is received through a UE Configuration Update Command message.

5. In paragraph 4, The above UE configuration update command message is: Additionally, a second NSSAI, which is a different NSSAI from the first NSSAI, is included. Performing the above new PDU session establishment is as follows: A method of operating a terminal, comprising performing establishment or modification of a second PDU session associated with the second NSSAI.

6. In paragraph 1, A method of operating a terminal, wherein, if the first NSSAI is a partially allowed NSSAI, the PDU session rejection message is a PDU session rejection message related to a partial TA (Tracking Area) within the current RA (Registration Area).

7. In paragraph 1, The PDU session connection permission information for each access type is as follows: This is information on allowing MA (Multi Access) PDU session connections by access type. Performing the above new PDU session establishment is as follows: A method of operating a terminal based on corresponding PDU session connection permission information depending on whether the above MA PDU session is 3GPP, non-3GPP, or a combination of the above 3GPP and the above non-3GPP.

8. In paragraph 1, The above PDU session rejection message is, Contains back-off timer value and cause information, A method of operating a terminal, wherein transmission of a PDU session request message associated with the first NSSAI is backed off based on the back-off timer value.

9. In paragraph 8, The SSC (Session and Service Continuity) mode of the PDU session associated with the above first NSSAI is SSC mode 3, A method of operating a terminal, comprising transmitting a PDU session modification request message associated with a second NSSAI before releasing a PDU session associated with the first NSSAI, if the PDU session request message associated with the first NSSAI is a PDU session modification request message.

10. In a communication device in a wireless communication system, Transmitter and receiver; at least one processor; and At least one memory storing instructions and being operably electrically connected to the at least one processor, Based on the above instruction being executed by the at least one processor, the operations performed are: Establish a PDU (protocol data unit) session associated with the first NSSAI (network slice selection assistance information); Transmitting a PDU session request message associated with the first NSSAI to the network; In response to the transmitted PDU session request message, a PDU session reject message is received from the network; Determine whether PDU session connection permission information by access type has been received from the above network; and A communication device, comprising: when receiving PDU session connection permission information by access type, performing a new PDU session request according to the PDU session connection permission information by access type.

11. In paragraph 10, A communication device in which the PDU session connection permission information for each access type is received through the PDU session rejection message.

12. In paragraph 11, The above PDU session rejection message is, Additionally, a second NSSAI, which is a different NSSAI from the first NSSAI, is included. A communication device, wherein the processor is configured to establish or modify a second PDU session associated with the second NSSAI when establishing the new PDU session.

13. In paragraph 10, A communication device in which the PDU session connection permission information for each access type is received via a UE Configuration Update Command message.

14. In paragraph 13, The above UE configuration update command message is: Additionally, a second NSSAI, which is a different NSSAI from the first NSSAI, is included. A communication device, wherein the processor is configured to establish or modify a second PDU session associated with the second NSSAI when establishing the new PDU session.

15. In paragraph 10, A communication device, wherein if the first NSSAI is a partially allowed NSSAI, the PDU session rejection message is a PDU session rejection message related to a partial TA (Tracking Area) within the current RA (Registration Area).

16. In paragraph 10, The PDU session connection permission information for each access type is as follows: This is information on allowing MA (Multi Access) PDU session connections by access type. A communication device, wherein the processor is configured to perform the new PDU session establishment based on corresponding PDU session connection permission information depending on whether the MA PDU session is 3GPP, non-3GPP, or a combination of the 3GPP and the non-3GPP.

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