Device and method for providing network slice intercommunication in a wireless communication system

Abstract

The present disclosure relates to a pre-fifth generation (5G) or 5G communication system that will be provided to support a higher data rate beyond the fourth generation (4G) communication system such as long term evolution (LTE). A method for operating a user equipment (UE) in a wireless communication system is provided. The method includes: sending a packet data network (PDN) connection request message to a first base station (BS); receiving information from the first BS about a first S-NSSAI selected by a combination of a packet data network gateway control plane entity (PGW-C) and a session management function (SMF) in at least one subscribed single network slice selection auxiliary information (S-NSSAI) of the UE; sending a registration request message including a requested NSSAI to a second BS, the registration request message including the first S-NSSAI; and receiving a registration acceptance message including an allowed NSSAI from the second BS, the registration acceptance message including a second S-NSSAI mapped to the first S-NSSAI.

Description

Technical Field

[0001] The present disclosure relates to a wireless communication system. More specifically, the present disclosure relates to an apparatus and method for providing network slicing in a wireless communication system. Background Art

[0002] To meet the increased demand for wireless data traffic since the deployment of the fourth generation (4G) communication system, efforts have been made to develop improved fifth generation (5G) or pre-5G communication systems. Therefore, 5G or pre-5G communication systems are also called "beyond 4G networks" or "late long term evolution (LTE) systems".

[0003] 5G communication systems are considered to be implemented in higher (mmWave) frequency bands, such as 28 GHz or 60 GHz bands, to achieve higher data rates. In order to reduce the propagation loss of radio waves and increase the transmission distance, beamforming, massive multiple-input multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive antenna technologies in 5G communication systems are discussed.

[0004] In addition, in the 5G communication system, system network improvements are being developed based on advanced small cells, cloud radio access networks (RAN), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, mobile networks, cooperative communications, coordinated multi-point (CoMP), receiving-end interference cancellation, etc.

[0005] In 5G systems, hybrid frequency shift keying (FSK) and quadrature amplitude modulation (FQAM) and sliding window superposition coding (SWSC) have been developed as advanced coded modulation (ACM), and filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) as advanced access technologies.

[0006] In 5G systems, various communication schemes are discussed. For example, an unlicensed communication scheme for sending data without authorized uplink transmission is proposed. In addition, various discussions are ongoing to effectively support unlicensed communication. The above information is presented only as background information to assist in understanding the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above may be applicable to the prior art in the field of the present disclosure.

[0007] Based on the above discussion, the present disclosure provides a method and device for intercommunication between an Evolved Packet System (EPS) network system and a 5G network system architecture to provide a network slicing function in a wireless communication system.

[0008] The above information is presented as background information only to assist in understanding the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above may be applicable as prior art in the field of the present disclosure. Summary of the invention

[0009] Technical Solution

[0010] Aspects of the present disclosure are intended to address at least the above-mentioned problems and / or disadvantages and to provide at least the advantages described below. Accordingly, one aspect of the present disclosure provides an apparatus and method for providing network slicing in a wireless communication system.

[0011] Additional aspects will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the presented embodiments.

[0012] According to one aspect of the present disclosure, a method for operating a user equipment (UE) in a wireless communication system is provided. The method includes: sending a packet data network (PDN) connection request message to a first base station (BS); receiving information from the first BS about a first S-NSSAI selected by a combination of a packet data network gateway control plane entity (PGW-C) and a session management function (SMF) from at least one subscribed single network slice selection auxiliary information (S-NSSAI) of the UE; sending a registration request message including a requested NSSAI to a second BS, the registration request message including the first S-NSSAI; and receiving a registration acceptance message including an allowed NSSAI from the second BS, the registration acceptance message including a second S-NSSAI mapped to the first S-NSSAI.

[0013] According to another aspect of the present disclosure, a user equipment (UE) in a wireless communication system is provided. The UE includes: a transceiver; and at least one processor, the at least one processor being operably coupled to the transceiver and configured to: send a packet data network (PDN) connection request message to a first base station (BS); receive information from the first BS about a first S-NSSAI selected by a combination of a packet data network gateway control plane entity (PGW-C) and a session management function (SMF) from at least one subscribed single network slice selection assistance information (S-NSSAI) of the UE; send a registration request message including a requested NSSAI to a second BS, the registration request message including the first S-NSSAI; and receive a registration acceptance message including an allowed NSSAI from the second BS, the registration acceptance message including a second S-NSSAI mapped to the first S-NSSAI.

[0014] The devices and methods according to multiple embodiments of the present disclosure provide a method for intercommunication between an EPS network system and a 5G network system architecture, thereby providing a network slicing function to effectively provide services in a mobile communication system.

[0015] Other aspects, advantages, and salient features of the disclosure will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses several embodiments of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and other aspects, features and advantages of certain embodiments of the present disclosure will become more apparent through the following description in conjunction with the accompanying drawings, in which:

[0017] Figure 1 The 5G network slice intercommunication structure (non-roaming) according to an embodiment of the present disclosure is shown;

[0018] Figure 2 A network slice interworking configuration (non-roaming) according to an embodiment of the present disclosure is shown;

[0019] Figure 3 A network slice interworking configuration (local breakout) according to an embodiment of the present disclosure is shown;

[0020] Figure 4 A network slice intercommunication configuration (home-routed roaming) according to an embodiment of the present disclosure is shown;

[0021] Figure 5 The session management function + packet data network gateway control (SMF+PGW-C) operation for supporting network slice interworking according to an embodiment of the present disclosure is shown;

[0022] Figure 6 The SMF+PGW-C operation for supporting network slice interworking according to an embodiment of the present disclosure is shown;

[0023] Figure 7 The configuration of a base station in a wireless communication system according to an embodiment of the present disclosure is shown;

[0024] Figure 8 The configuration of a UE in a wireless communication system according to an embodiment of the present disclosure is shown;

[0025] Fig. 9 shows the configuration of a core network device in a wireless communication system according to an embodiment of the present disclosure; and

[0026] Fig.10The 5G network registration process of the UE according to an embodiment of the present disclosure is shown.

[0027] Throughout the drawings, like reference numerals will be understood to refer to like parts, components, and structures. DETAILED DESCRIPTION

[0028] The present disclosure provides the following description with reference to the accompanying drawings to assist in a comprehensive understanding of the various embodiments of the present disclosure as defined by the claims and their equivalents. It includes various specific details to assist in understanding, but these details are considered exemplary only. Therefore, one of ordinary skill in the art will recognize that various changes and modifications may be made to the various embodiments described herein without departing from the scope and spirit of the present disclosure. In addition, for the sake of clarity and brevity, descriptions of well-known functions and configurations may be omitted.

[0029] The terms and words used in the following description and claims are not limited to the bibliographic meanings, but are only used by the inventor to help readers understand the present disclosure clearly and consistently. Accordingly, it should be clear to those skilled in the art that the following description of multiple embodiments of the present disclosure is provided for illustrative purposes only and is not intended to limit the present disclosure as defined by the attached claims and their equivalents.

[0030] It should be understood that the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a component surface" also includes reference to one or more of such surfaces.

[0031] The terms used in this disclosure are only used to describe specific embodiments and are not used to limit the scope of other embodiments. Unless otherwise defined, all terms used herein, including technical and scientific terms, may have the same meaning as the meaning generally understood by those skilled in the art to which the present disclosure belongs. Terms defined in general dictionaries, etc. may be interpreted as having the same or similar meaning as the contextual meaning in the relevant field, and unless clearly defined in the present disclosure, should not be interpreted as having an ideal or overly formal meaning. In some cases, even the terms defined in the present disclosure should not be interpreted as excluding multiple embodiments of the present disclosure.

[0032] Hereinafter, multiple embodiments of the present disclosure will be described based on hardware. However, multiple embodiments of the present disclosure include technologies using both hardware and software, and thus multiple embodiments of the present disclosure do not exclude software-based methods.

[0033] The present disclosure relates to a device and method for providing network slicing interworking in a wireless communication system. Specifically, the present disclosure describes a technology for interworking between an EPS network system and a 5G network system architecture to provide network slicing functionality in a wireless communication system.

[0034] The terms used below are shown for the convenience of description, and include terms indicating signals, terms indicating channels, terms indicating control information, terms indicating network entities, and terms indicating device elements. Accordingly, the present disclosure is not limited to the following terms and other terms with the same technical meanings may be used.

[0035] In addition, the present disclosure uses terms used in some communication standards (eg, the Third Generation Partnership Project (3GPP)) to describe multiple embodiments, but the embodiments are only for illustration. Multiple embodiments of the present disclosure can be easily modified and applied to other communication systems.

[0036] In the 3GPP standard, the 5G network system architecture and process are standardized. Mobile operators can provide a variety of services in 5G networks. In order to provide each service, mobile operators need to meet the different service requirements of each service (for example, latency, communication range, data rate, bandwidth, reliability, etc.). To this end, mobile operators can build network slices and allocate network resources suitable for specific services based on network slices or sets of network slices. Network resources can indicate network functions (NFs), logical resources provided by NFs, or radio resource allocations of base stations.

[0037] For example, a mobile operator can build network slice A to provide mobile broadband services, network slice B to provide vehicle communication services, and network slice C to provide IoT services. As described above, in a 5G network, corresponding services can be provided on network slices dedicated to each service characteristic. Single Network Slice Selection Assistance Information (S-NSSAI) defined by 3GPP can be used as an identifier to identify a network slice.

[0038] Mobile operators can operate both 5G networks and EPS (or LTE) networks at the same time. Mobile communication UEs can move to the EPS network while accessing the 5G network and using services. In addition, mobile communication UEs can move to the 5G network while accessing the EPS network and using services.

[0039] The present disclosure defines a method for intercommunication between an EPS network system and a 5G network system architecture to provide network slicing functionality. Figure 1 , 2 and 3 show the interworking structure of the 5G system (5GS) and the evolved packet system (EPS).

[0040] In addition, the present disclosure also defines network operations and UE operations, in which a session connection is established in EPS so that a UE capable of using a communication service can use the service without being disconnected even when the UE moves to 5GS.

[0041] Figure 1 The interworking structure of 5GS and EPS in a non-roaming case according to an embodiment of the present disclosure is shown.

[0042] Reference Figure 1 , 5GS may include a new radio (NR) base station 150, an access and mobility management function (AMF) 145, a session management function (SMF) 120, a user plane function (UPF) 125, a policy control function (PCF) 115, and a unified data management (UDM) 110. EPS may include an evolved universal terrestrial radio access (E-UTRA) base station 140, a mobility management entity (MME) 135, a serving gateway (SGW) 130, a packet data network gateway-user (PGW-U) 125, a packet data network gateway control (PGW-C) 120, a policy and charging rules function (PCRF) 115, and a home subscriber service (HSS) 110. The UDM 110 of 5GS and the HSS 110 of EPS may be constructed as a single combined node. The SMF 120 of 5GS and the PGW-C 120 of EPS may be constructed as a single combined node. The node of UDM+HSS 110 may store UE subscription information. The UPF 125 of 5GS and the PGW-U 125 of EPS can be configured as a single combined node. The UE 155 can access the MME 135 of EPS via the E-UTRA base station 140 to use EPS network services. In addition, the UE 155 can access the AMF 145 of 5GS via the NR base station 150 to use 5GS network services.

[0043] Figure 2 FIG. 2 shows the intercommunication structure of 5GS and EPS in the case of local service unblocking roaming according to an embodiment of the present disclosure. Figure 1 As shown, UE 260 can access MME 240 of EPS via E-UTRA base station 245 to use EPS network services.

[0044] Reference Figure 2 In addition, UE 260 can access AMF 250 of 5GS via NR base station 255 to use 5GS network services. In the interworking structure of 5GS and EPS in the case of local service unblocking roaming, the node of SMF+PGW-C 225 can be located in the visited PLMN (VPLMN). Figure 1 and Figure 2 N1, N2, N3, N8, N10, N11, N15, N26, S1-MME, S1-U, S6a, S11, S5-C and S5-U shown in represent interfaces between network elements in EPS and 5GS.

[0045] Figure 3FIG. 2 shows the intercommunication structure of 5GS and EPS in the case of home domain routing roaming according to an embodiment of the present disclosure. Figure 1 As shown, UE 370 can access MME 335 of EPS via E-UTRA base station 340 to use EPS network services.

[0046] Reference Figure 3 In addition, UE 370 can access AMF 360 of 5GS via NR base station (NG-RAN) 365 to use 5GS network services. In the interworking structure of 5GS and EPS in the case of home domain routing roaming, the node of SMF+PGW-C 320 can be located in the home domain PLMN (HPLMN). Figure 3 N1, N2, N3, N8, N9, N10, N11, N15, N16, N24, N26, S1-MME, S1-U, S6a, S11, S8-C and S8-U shown in represent interfaces between network elements in EPS and 5GS.

[0047] Figure 4 A process of establishing a packet data network (PDN) connection in EPS by the UE 410 according to an embodiment of the present disclosure is shown.

[0048] See also Figure 4 , UE 410 can establish a PDN connection by accessing MME 420 via E-UTRA base station 415 to exchange signaling messages with PGW-C 430 located in EPS. When establishment of the PDN connection is completed, UE 410 can send uplink data to PGW-U 435 or receive downlink data from PGW-U 435.

[0049] Procedure 1: UE 410 may send a PDN connection request message to MME 420 to establish a PDN connection. The PDN connection request message may be sent to MME 420 via E-UTRA base station 415.

[0050] Process 2: After receiving the PDN connection request message in process 1, the MME 420 may send a create session request message to the S-GW 425.

[0051] Process 3: After receiving the create session request message in process 2, the S-GW 425 may send a create session request message to the SMF+PGW-C 430.

[0052] Process 4: After receiving the create session request message in process 3, SMF+PGW-C 430 can perform an Internet Protocol Connection Access Network (IP-CAN) session establishment / modification process together with PCF+PCRF 440.

[0053] Process 5: After receiving the create session request message in process 3, SMF+PGW-C 430 may send a Nudm_SDM_Get request message to UDM+HSS445. The Nudm_SDM_Get request message may include the data type of the requested subscription information, and key information accessible to the data type of the subscription information. According to an embodiment of the present disclosure, "slice selection subscription data" may be included as the data type of the requested subscription information, and the UE ID "SUPI" may be included as a key accessible to the data type of the subscription information.

[0054] Process 6: After receiving the Nudm_SDM_Get request message in process 5, when the Nudm_SDM_Get request message includes the parameter "slice selection subscription data", the UDM+HSS 445 may retrieve the UE network slice subscription information corresponding to the received UEID SUPI from the database (UDR). According to an embodiment of the present disclosure, the network slice subscription information may be configured by at least one S-NSSAI, and is referred to as the subscribed S-NSSAI. After retrieving the subscribed S-NSSAI of the UE corresponding to the received SUPI, the UDM+HSS 445 may send a Nudm_SDM_Get response message to the SMF+PGW-C 430. The Nudm_SDM_Get response message may include the "subscribed S-NSSAI" information of the UE corresponding to the SUPI. The "subscribed S-NSSAI" may include at least one default S-NSSAI. In order to describe the present disclosure, the "subscribed S-NSSAI" may be described by the following example.

[0055] Subscribed S-NSSAI: {S-NSSAI 1, S-NSSAI 2, S-NSSAI 3 (default)}

[0056] UE 410 subscribes to three S-NSSAIs, and it can be assumed that, among the three S-NSSAIs, S-NSSAI 3 is the default S-NSSAI.

[0057] When the PLMN ID included in the UE ID SUPI matches the PLMN ID where the SMF+PGW-C 430 is located (i.e., corresponding to Figure 1 and Figure 3 ), if Figure 5 As shown, after receiving the Nudm_SDM_Get response message, the SMF+PGW-C 430 may perform an operation of the SMF+PGW-C 430 that enables the SMF+PGW-C 430 to select the S-NSSAI.

[0058] Figure 5The SMF+PGW-C operation for supporting network slice intercommunication according to an embodiment of the present disclosure is shown.

[0059] Reference Figure 5 , operations 510, 515, and 520 correspond to Figure 4 After receiving the Nudm_SDM_Get response message (operation 520), SMF+PGW-C 430 may identify (operation 525) whether the S-NSSAI that SMF+PGW-C 430 may provide is included in the "subscribed S-NSSAI" included in the Nudm_SDM_Get response message received in process 6.

[0060] When there is no S-NSSAI that the SMF+PGW-C 430 can provide (operation 530), or when there is no S-NSSAI that matches the "subscribed S-NSSAI" received in process 6 among one or more S-NSSAIs that the SMF+PGW-C 430 can provide (operation 530), the SMF+PGW-C 430 may select a default S-NSSAI from the "subscribed S-NSSAI" received in process 6 (method 1), or may not select any S-NSSAI (method 2). In operation 550, the SMF-PGW-C may not include slice information in the create session response (method 2_1), or the SMF-PGW-C may reject the create session request (method 2_2). Alternatively, in operation 545, the create session response message of process 9 may include slice information that has been selected through the process.

[0061] When there is one S-NSSAI that the SMF+PGW-C 430 can provide and the corresponding S-NSSAI is included in the "subscribed S-NSSAI" received in process 6 (operation 535), or when there is one S-NSSAI that matches the "subscribed S-NSSAI" received in process 6 among two or more S-NSSAIs that the SMF+PGW-C 430 can provide (operation 535), the SMF+PGW-C 430 can select one S-NSSAI that can be provided by the SMF+PGW-C 430 and included in the "subscribed S-NSSAI". In operation 545, the create session response message of process 9 may include the slice information that has been selected through the process.

[0062] When there are two or more S-NSSAIs that the SMF+PGW-C 430 can provide, and among them, two or more S-NSSAIs are included in the “subscribed S-NSSAI” (operation 540), based on the mobile operator policy configured in the SMF+PGW-C 430, the SMF+PGW-C 430 may select one S-NSSAI from the two or more S-NSSAIs that are included in the “subscribed S-NSSAI” and that can be provided by the SMF+PGW-C 430. In operation 545, the create session response message of process 9 may include the slice information that has been selected through the process.

[0063] When the PLMN ID contained in the UE ID SUPI matches the PLMN ID where the SMF+PGW-C 430 is located (i.e., corresponding to Figure 1 and Figure 3 ), processes 7 and 8 may not be performed.

[0064] When the PLMN ID included in the UE ID SUPI does not match the PLMN ID where the SMF+PGW-C 430 is located (i.e., corresponding to Figure 2 ), processes 7 and 8 may be performed.

[0065] Process 7: After receiving the Nudm_SDM_Get response message in process 6, SMF+PGW-C 430 may send a Nnssf_NSSelection_Get request message to NSSF450. The Nnssf_NSSelection_Get request message may include the "PLMN ID" included in the UEID SUPI and the "Subscribed S-NSSAI" of the UE received from UDM+HSS 445 in process 6. The "PLMN ID" included in the SUPI may indicate the HPLMN of the UE. The "Subscribed S-NSSAI" may indicate the slice information used in the HPLMN of the UE.

[0066] Process 8: After receiving the Nnssf_NSSelection_Get request message in process 7, the NSSF 450 may derive a "mapped S-NSSAI" that is mapped with the "subscribed S-NSSAI" included in the request message for use in the VPLMN. To describe the present disclosure, the "subscribed S-NSSAI" and the "mapped S-NSSAI" may be described by the following example.

[0067] Subscribed S-NSSAI: {S-NSSAI 1, S-NSSAI 2, S-NSSAI 3 (default)}

[0068] Mapped S-NSSAI: {(S-NSSAI 1, S-NSSAI a), (S-NSSAI 2, S-NSSAI b), (S-NSSAI 3, S-NSSAI c)}

[0069] The S-NSSAI included in the "subscribed S-NSSAI" may be configured by a slice value (e.g., S-NSSAI 1) used in the UE HPLMN. The S-NSSAI included in the "mapped S-NSSAI" may be configured by a pair (e.g., (S-NSSAI 1, S-NSSAI a)) of slice values ​​(e.g., S-NSSAI a) mapped with a slice value (e.g., S-NSSAI 1) used in the UE HPLMN for use in the VPLMN.

[0070] NSSF 450 may send a Nnssf_NSSelection_Get response message to SMF+PGW-C 430. The Nnssf_NSSelection_Get response message may include "Mapped S-NSSAI".

[0071] After receiving the Nnssf_NSSelection_Get response message, the SMF+PGW-C 430 may perform operations of the SMF+PGW-C 430 that enable the SMF+PGW-C 430 to select the S-NSSAI, such as Figure 6 shown.

[0072] Figure 6 The SMF+PGW-C operation for supporting network slice intercommunication according to an embodiment of the present disclosure is shown.

[0073] Reference Figure 6 , operations 610, 615, and 620 correspond to Figure 4 3, 6 and 8 in the above process. After receiving the Nnssf_NSSelection_Get response message (operation 620), the SMF+PGW-C 430 may identify (operation 625) whether the S-NSSAI provided by the SMF+PGW-C 430 by using the "mapped S-NSSAI" included in the Nnssf_NSSelection_Get response message is included in the "subscribed S-NSSAI" included in the Nudm_SDM_Get response message received in process 6. For the above operation, the SMF+PGW-C 430 may interpret the "subscribed S-NSSAI" information using the received "mapped S-NSSAI" information.

[0074] For example, when the slice provided by SMF+PGW-C 430 is S-NSSAI a, SMF+PGW-C 430 can use the received "mapped S-NSSAI" information to identify that S-NSSAI 1 mapped to S-NSSAI a which is the slice provided by SMF+PGW-C 430 is included in the "subscribed S-NSSAI".

[0075] Subscribed S-NSSAI: {S-NSSAI 1, S-NSSAI 2, S-NSSAI 3 (default)}

[0076] Mapped S-NSSAI: {(S-NSSAI 1, S-NSSAI a), (S-NSSAI 2, S-NSSAI b), (S-NSSAI 3, S-NSSAI c)}

[0077] In addition, for example, when the slice provided by SMF+PGW-C 430 is S-NSSAI d, SMF+PGW-C 430 can use the received "mapped S-NSSAI" information to identify that S-NSSAI d, which is the slice provided by SMF+PGW-C 430, is not included in the "subscribed S-NSSAI".

[0078] Subscribed S-NSSAI: {S-NSSAI 1, S-NSSAI 2, S-NSSAI 3 (default)}

[0079] Mapped S-NSSAI: {(S-NSSAI 1, S-NSSAI a), (S-NSSAI 2, S-NSSAI b), (S-NSSAI 3, S-NSSAI c)}

[0080] For example, when the slices provided by SMF+PGW-C 430 are S-NSSAI a and S-NSSAI d, SMF+PGW-C 430 can use the received "mapped S-NSSAI" information to identify that S-NSSAI a is included in the "subscribed S-NSSAI" but S-NSSAI d is not included in the "subscribed S-NSSAI" in the slices provided by SMF+PGW-C 430.

[0081] Subscribed S-NSSAI: {S-NSSAI 1, S-NSSAI 2, S-NSSAI 3 (default)}

[0082] Mapped S-NSSAI: {(S-NSSAI 1, S-NSSAI a), (S-NSSAI 2, S-NSSAI b), (S-NSSAI 3, S-NSSAI c)}

[0083] For example, when the slices provided by SMF+PGW-C 430 are S-NSSAI a and S-NSSAI c, SMF+PGW-C 430 can use the "mapped S-NSSAI" information received as follows to identify that S-NSSAIa and S-NSSAI c provided by SMF+PGW-C 430 are both included in the "subscribed S-NSSAI".

[0084] Subscribed S-NSSAI: {S-NSSAI 1, S-NSSAI 2, S-NSSAI 3 (default)}

[0085] Mapped S-NSSAI: {(S-NSSAI 1, S-NSSAI a), (S-NSSAI 2, S-NSSAI b), (S-NSSAI 3, S-NSSAI c)}

[0086] When there is no S-NSSAI that the SMF+PGW-C 430 can provide (operation 630), or when there is no S-NSSAI that matches the "subscribed S-NSSAI" received in process 6 among one or more S-NSSAIs (e.g., S-NSSAI d) that the SMF+PGW-C 430 can provide (operation 630), the SMF+PGW-C 430 may select a default S-NSSAI from the "subscribed S-NSSAI" received in process 6 (method 1), or may not select any S-NSSAI (method 2). In operation 650, the SMF-PGW-C may not include slice information in the create session response (method 2_1), or the SMF-PGW-C may reject the create session request (method 2_2). Alternatively, in operation 645, the create session response message of process 9 may include slice information that has been selected through the process.

[0087] When there is one S-NSSAI (e.g., S-NSSAI a) that the SMF+PGW-C 430 can provide and the corresponding S-NSSAI is included in the “subscribed S-NSSAI” (e.g., S-NSSAI 1 mapped to S-NSSAI a) received in process 6 (operation 635), or when there is one S-NSSAI that matches the “subscribed S-NSSAI” received in process 6 (e.g., S-NSSAI 1 mapped to S-NSSAI a, and there is no S-NSSAI of the HPLMN mapped to S-NSSAI d) among two or more S-NSSAIs (e.g., S-NSSAI a and S-NSSAI d) that the SMF+PGW-C 430 can provide (operation 635), the SMF+PGW-C 430 can select one S-NSSAI that can be provided by the SMF+PGW-C 430 and included in the “subscribed S-NSSAI”. That is, in operation 645, the create session response message of process 9 may include slice information that has been selected by the process.

[0088] When there are two or more S-NSSAIs that the SMF+PGW-C 430 can provide, and among them, two or more S-NSSAIs are included in the “subscribed S-NSSAI” (operation 640), based on the mobile operator policy configured in the SMF+PGW-C 430, the SMF+PGW-C 430 may select one S-NSSAI from the two or more S-NSSAIs that are included in the “subscribed S-NSSAI” and that can be provided by the SMF+PGW-C 430. That is, in operation 645, the create session response message of process 9 may include the slice information that has been selected through the process.

[0089] Process 9: Receive the Nudm_SDM_Get response message (i.e. Figure 1 and Figure 3 ) or in process 8, a Nnssf_NSSelection_Get response message is received (i.e. Figure 2 After that, SMF+PGW-C 430 may send a create session response message to S-GW 425.

[0090] The create session response message may include Figure 5 and Figure 6The slice information selected in the process of creating a session in the form of a protocol configuration option (PCO) (operations 545, 645). The slice information included in the create session response message may include various methods. The slice information included in the create session response message may be sent to the UE 410 through processes 10, 11 and 12.

[0091] In addition, SMF+PGW-C 430 may store the data in UDM+HSS 445. Figure 5 or Figure 6 The S-NSSAI of the slice information selected in the process and the PDN connection information supported by the S-NSSAI (for example, PDN connection ID, etc.).

[0092] In the case of local service unblocking roaming (i.e. Figure 2 According to an embodiment of the present disclosure, an example of slice information included in a create session response message will be described. To describe an embodiment of the present disclosure, it is assumed that SMF+PGW-C 430 performs Figure 6 Select S-NSSAI 1 as follows.

[0093] Subscribed S-NSSAI: {S-NSSAI 1, S-NSSAI 2, S-NSSAI 3 (default)}

[0094] Mapped S-NSSAI: {(S-NSSAI 1, S-NSSAI a), (S-NSSAI 2, S-NSSAI b), (S-NSSAI 3, S-NSSAI c)}

[0095] [LB embodiment 1]: SMF+PGW-C 430 according to an embodiment of the present disclosure may allow S-NSSAI a mapped to the selected S-NSSAI 1 to be used in the VPLMN to be included in the Create Session Response message in the form of a Protocol Configuration Option (PCO). The PCO may include the PLMN ID using S-NSSAI a, i.e., the VPLMN ID.

[0096] Create session response message: {…,PCO(S-NSSAI a)}

[0097] [LB embodiment 2]: SMF+PGW-C 430 may allow S-NSSAI a mapped to the selected S-NSSAI 1 used in the VPLMN, and mapping information corresponding to S-NSSAI a, to be included in the create session response message in the form of PCO. The PCO may include the PLMN ID using S-NSSAI a, i.e., the VPLMN ID.

[0098] Create session response message: {…,PCO(S-NSSAI a,(S-NSSAI 1,S-NSSAI a))}

[0099] or

[0100] Create session response message: {…,PCO((S-NSSAI 1,S-NSSAI a))}

[0101] [LB embodiment 3]: SMF+PGW-C 430 may allow the selected S-NSSAI 1 to be included in the Create Session Response message in the form of PCO. The PCO may include the PLMN ID using S-NSSAI 1, namely, the HPLMN ID.

[0102] Create session response message: {…,PCO(S-NSSAI 1)}

[0103] [LB embodiment 4]: SMF+PGW-C 430 may allow the selected S-NSSAI 1 and the mapping information corresponding to S-NSSAI 1 to be included in the create session response message in the form of PCO. The PCO may include the PLMN ID using S-NSSAI 1, i.e., the HPLMN ID, and the PLMN ID using S-NSSAI a, i.e., the VPLMN ID.

[0104] Create session response message: {…,PCO(S-NSSAI 1,(S-NSSAI 1,S-NSSAI a))}

[0105] or

[0106] Create session response message: {…,PCO((S-NSSAI 1,S-NSSAI a))}

[0107] [LB Example 5]: SMF+PGW-C 430 may allow the selected slice information not to be included in the create session response message.

[0108] Create a session response message: {…}

[0109] In the case of home domain routing roaming (i.e. Figure 3 According to an embodiment of the present disclosure, an example of slice information included in a create session response message will be described. To describe an embodiment of the present disclosure, it is assumed that SMF+PGW-C 430 performs Figure 5 Select S-NSSAI 1 as follows.

[0110] Subscribed S-NSSAI: {S-NSSAI 1, S-NSSAI 2, S-NSSAI 3 (default)}

[0111] [HR Embodiment 1]: SMF+PGW-C 430 according to an embodiment of the present disclosure may allow the selected S-NSSAI 1 to be included in the Create Session Response message in the form of PCO. The PCO may include the PLMN ID using S-NSSAI 1, ie, the HPLMN ID.

[0112] Create session response message: {…,PCO(S-NSSAI 1)}

[0113] [HR Embodiment 2]: SMF+PGW-C 430 may allow the selected slice information not to be included in the create session response message.

[0114] Create a session response message: {…}

[0115] Process 10: After receiving the create session response message in process 9, S-GW 425 may send a create session response message to MME 420. The create session response message sent by S-GW 425 to MME 420 may include the slice information included in the create session response message received in process 9.

[0116] Process 11: After receiving the create session response message in process 10, the MME 420 may send a bearer establishment request message or a "downlink NAS transfer and PDN connection accept" message to the E-UTRA base station 415. The message sent by the MME 420 to the E-UTRA base station 415 may include the slice information included in the create session response message received in process 10.

[0117] Process 12: After receiving the bearer establishment request message or the "downlink NAS transfer and PDN connection acceptance" message in process 11, the E-UTRA base station 415 can send an RRC connection reconfiguration message or an RRC direct transfer message to the UE 410. The message sent by the E-UTRA base station 415 to the UE 410 may include the slice information included in the message received in process 11.

[0118] After receiving the RRC connection reconfiguration message or the RRC direct transfer message, the UE 410 may store the S-NSSAI, ie, the slice information included in the message, and the PLMN ID using the corresponding S-NSSAI. The slice information may be included in the message in the form of a PCO.

[0119] Process 13: After receiving the RRC connection reconfiguration message in process 12, the UE 410 may send an RRC connection reconfiguration complete message to the E-UTRA base station 415.

[0120] Process 14: After receiving the RRC connection reconfiguration complete message in process 13, the E-UTRA base station 415 may send a bearer establishment response message to the MME 420.

[0121] Process 15: After receiving the RRC direct transfer message in process 12, the UE 410 may send a direct transfer message to the E-UTRA base station 415.

[0122] Process 16: After receiving the direct transfer message in process 15, the E-UTRA base station 415 may send a PDN connection complete message to the MME 420. Process 17: The MME 420 sends a modify bearer request to the S-GW 425. Process 18: The S-GW 425 forwards the modify bearer request to the SMF+PGW-C 430. Process 19: The SMF+PGW-C 430 sends a modify bearer response to the S-GW 425. Process 20: The S-GW 425 forwards the modify bearer response to the MME 420.

[0123] like Figure 4 As shown, according to an embodiment of the present disclosure, a UE can access an EPS network to establish a PDN connection and send or receive data. The UE can move to a 5GS network, at which time the UE can provide information related to the PDN connection established in the EPS network to the 5GS network.

[0124] Fig.10 10. The process of a UE moving to a 5G network to perform a registration process according to an embodiment of the present disclosure is shown. More specifically, the UE 260, 370 or 1010 moves to the 5GS to send a registration request message to the AMF 250, 360 or 1020.

[0125] See also Fig.10 , the registration request message may include PDN connection related information established in the EPS network. PDN connection related information may include requested NSSAI, that is, slice information requested by the UE, and other slice information (for example, mapping information, indication, PLMN ID using S-NSSAI included in the requested NSSAI, etc.). The requested NSSAI may be configured by at least one S-NSSAI. The registration request message may be sent to AMF 250, 360 or 1020 via NG-RAN 255, 365 or 1015. The PDN connection related information included in the registration request message may include various methods.

[0126] In the following, in the case of local service unblocking roaming (i.e. Figure 2 ), an example of a method for providing PDN connection related information established in EPS to a 5GS network according to an embodiment of the present disclosure will be described.

[0127] According to an embodiment, in Figure 4 In the case of [LB embodiment 1] of process 9 in the embodiment of the present disclosure, the registration request message sent by the UE 260 or 1010 to the AMF 250 or 1020 via the NG-RAN 255 or 1015 according to the embodiment of the present disclosure may include Figure 4 The S-NSSAI a received in process 12 is used as the requested NSSAI, and may include the PLMN ID using the S-NSSAI a, that is, the VPLMN ID.

[0128] According to an embodiment, in Figure 4 In the case of [LB embodiment 2] of process 9 in the embodiment of the present disclosure, the registration request message sent by the UE 260 or 1010 to the AMF 250 or 1020 via the NG-RAN 255 or 1015 according to the embodiment of the present disclosure may include Figure 4 The S-NSSAI a received in process 12 is used as the requested NSSAI, and may include mapping information corresponding to S-NSSAI a (S-NSSAI 1, S-NSSAI a), and the PLMN ID using S-NSSAI a, that is, the VPLMN ID.

[0129] When the ID of the UE (e.g., 5G-GUTI, GUTI, or SUPI) includes information allocated in the EPS, or when the received registration request message includes the VPLMN ID, the AMF 250 or 1020 according to [LB embodiment 1] and [LB embodiment 2] can recognize that the requested NSSAI included in the registration request received from the UE is configured by the S-NSSAI value used in the VPLMN.

[0130] According to an embodiment, in Figure 4 In the case of [LB embodiment 3] of process 9 in the embodiment of the present disclosure, the registration request message sent by the UE 260 or 1010 to the AMF 250 or 1020 via the NG-RAN 255 or 1015 according to the embodiment of the present disclosure may include Figure 4 The S-NSSAI 1 received in process 12 in the above procedure is used as the requested NSSAI, and may include the PLMN ID using S-NSSAI 1, namely the HPLMN ID.

[0131] According to an embodiment, in Figure 4 In the case of [LB embodiment 4] of process 9 in the embodiment of the present disclosure, the registration request message sent by the UE 260 or 1010 to the AMF 250 or 1020 via the NG-RAN 255 or 1015 according to the embodiment of the present disclosure may include Figure 4The S-NSSAI 1 received in process 12 is used as the requested NSSAI, and may include mapping information corresponding to S-NSSAI 1 (S-NSSAI 1, S-NSSAI a), and the PLMN ID using S-NSSAI 1, namely, the HPLMN ID.

[0132] When the ID of the UE (e.g., 5G-GUTI, GUTI, or SUPI) includes information allocated in the EPS, or when the received registration request message includes the HPLMN ID, the AMF 250 or 1020 according to [LB Example 3] and [LB Example 4] can identify that the requested NSSAI included in the registration request received from the UE is configured by the S-NSSAI value used in the HPLMN.

[0133] According to an embodiment, in Figure 4 In the case of [LB embodiment 5] of process 9 in, the registration request message sent by UE 260 or 1010 to AMF 250 or 1020 via NG-RAN 255 or 1015 according to an embodiment of the present disclosure may not include slice related information. That is, the registration request message may not include the requested NSSAI.

[0134] When the ID of the UE (e.g., 5G-GUTI, GUTI, or SUPI) includes information allocated in the EPS, the AMF 250 or 1020 according to [LB Embodiment 5] can recognize that the UE is a UE moved from the EPS. The AMF 250 or 1020 can Figure 2 The UDM 210 or 1030 obtains the PDN connection information configured by the UE in the EPS, and the S-NSSAI information supported by the PDN connection. The AMF 250 or 1020 may allow the S-NSSAI supported by the PDN connection obtained from the UDM 210 or 1030 to be included in the allowed NSSAI of the registration accept message to be sent to the UE, and then may send the S-NSSAI.

[0135] In the following, in the case of home domain routing roaming (i.e. Figure 3 ), according to an embodiment of the present invention, an example of a method for providing information related to a PDN connection established in EPS to a 5GS network will be described.

[0136] According to an embodiment, in Figure 4 In the case of [HR embodiment 1] of process 9 in the embodiment of the present disclosure, the registration request message sent by the UE 370 or 1010 to the AMF 360 or 1020 via the NG-RAN 365 or 1015 according to the embodiment of the present disclosure may include Figure 4The S-NSSAI 1 received in process 12 in the above process is used as the requested NSSAI. When the registration request message includes the S-NSSAI 1, the registration request message may include the PDU session state of the S-NSSAI 1.

[0137] According to an embodiment, in Figure 4 In the case of [HR embodiment 1] of process 9 in the embodiment of the present disclosure, the registration request message sent by the UE 370 or 1010 to the AMF 360 or 1020 via the NG-RAN 365 or 1015 according to the embodiment of the present disclosure may include Figure 4 The S-NSSAI 1 received in process 12 of the registration request message may be used as the requested NSSAI, and may include an indication indicating that the S-NSSAI 1 is a value used in the HPLMN. When the S-NSSAI 1 is included in the registration request message, the PDU session status of the S-NSSAI 1 may be included in the registration request message.

[0138] According to an embodiment, in Figure 4 In the case of [HR embodiment 1] of process 9 in the embodiment of the present disclosure, the registration request message sent by the UE 370 or 1010 to the AMF 360 or 1020 via the NG-RAN 365 or 1015 according to the embodiment of the present disclosure may include Figure 4 The S-NSSAI 1 received in process 12 in the registration request message is used as the requested NSSAI, and the PLMN ID, that is, the HPLMN ID, using the S-NSSAI 1 may be included. When the S-NSSAI 1 is included in the registration request message, the PDU session state of the S-NSSAI 1 may be included in the registration request message.

[0139] When the ID of the UE (e.g., 5G-GUTI, GUTI, or SUPI) is included in information allocated in the EPS, when the received registration request message includes the HPLMN ID, or when the received registration request message includes an indication indicating the HPLMN value, the AMF 360 or 1020 according to [HR Embodiment 1] can recognize that the requested NSSAI included in the registration request received from the UE is configured by the S-NSSAI value used in the HPLMN.

[0140] exist Fig.10 In process 5 (operation 1055) of FIG. 1 , AMF 360 or 1020 may receive Figure 3 The UDM 310 or 1030 in the AMF 360 or 1020 obtains the "subscribed S-NSSAI" information of the UE corresponding to the UE ID. The AMF 360 or 1020 may compare the requested NSSAI received from the UE 1010 with the subscription slice information obtained from the UDM. If the S-NSSAI included in the requested NSSAI is included in the subscription slice information, the AMF 360 or 1020 performs Fig.10 Alternatively, Fig.10 The process 5 (operation 1055) in is omitted and the process 6 (operation 1060) can be directly executed. Fig.10 In process 6 (operation 1060) in, AMF 360 or 1020 may send a NSSelection_Get request message to NSSF 1025. The NSSelection_Get request message may include UE subscription slice information, a PLMN ID (i.e., HPLMN ID) included in a UE ID (e.g., SUPI), an HPLMN S-NSSAI value (S-NSSAI 1 according to an embodiment of the present disclosure) received from the UE and through which the UE establishes a session, and a requested NSSAI received from the UE.

[0141] NSSF 1025 may determine a VPLMN S-NSSAI value that is mapped to a HPLMN S-NSSAI value (e.g., a HPLMN S-NSSAI value included in a requested NSSAI) received from AMF 360 or 1020 and that is available in a VPLMN (i.e., a serving PLMN to which the UE is currently accessing). NSSF 1025 may determine an allowed NSSAI based on UE subscription slice information, a VPLMN S-NSSAI value determined by the NSSF, and a requested NSSAI value. The allowed NSSAI may be configured by at least one VPLMN S-NSSAI value available in a serving PLMN to which the UE is currently accessing. NSSF 1025 may send an NSSelection_Get response message to AMF 360 or 1020. The NSSelection_Get response message may include the allowed NSSAI determined by the NSSF, and a mapping of the allowed NSSAI to the allowed NSSAI. Upon receiving the NSSelection_Get response message, AMF 360 or 1020 may Fig.10 1065) and 1070) in the process 7 of the registration acceptance message to the UE 1010. The registration acceptance message may include the allowed NSSAI received from the NSSF and the mapping of the allowed NSSAI. After receiving the registration acceptance message, the UE 1010 may store the mapping of the allowed NSSAI and the allowed NSSAI included in the registration acceptance message, and may use them to manage (create / modify / delete) the PDU session in the current registration area, and send or receive data.

[0142] According to an embodiment, in Figure 4In the case of [HR embodiment 1] of process 9 in the embodiment of the present disclosure, the registration request message sent by the UE 370 or 1010 to the AMF 360 or 1020 via the NG-RAN 365 or 1015 according to the embodiment of the present disclosure may not include the requested NSSAI, or the S-NSSAI value may be configured as "unknown" in the requested NSSAI. In addition, the registration request message may include mapping information (S-NSSAI 1, unknown). That is, the UE may include in Figure 4 The S-NSSAI1 received in process 12 of the above process is used as the HPLMN S-NSSAI value of the mapping information, and the VPLMN S-NSSAI value may be configured as "unknown", or may not include any value (null). When the S-NSSAI1 is included in the registration request message, the PDU session status of S-NSSAI 1 may be included in the registration request message.

[0143] exist Fig.10 In process 5 (operation 1055) in [HR embodiment 1], the AMF 360 or 1020 according to [HR embodiment 1] may obtain the "subscribed S-NSSAI" information of the UE corresponding to the UE ID from the UDM 310 or 1030. The AMF 360 or 1020 may compare the S-NSSAI value received from the UE and used in the HPLMN with the subscription slice information obtained from the UDM. If the HPLMN S-NSSAI value received from the UE is included in the subscription slice information, then the subscription slice information may be obtained. Fig.10 Alternatively, Fig.10 Process 5 (operation 1055) in the above description is omitted and process 6 (operation 1060) may be performed. AMF 360 or 1020 may send a NSSelection_Get request message to NSSF 1025 (operation 1055). The NSSelection_Get request message may include UE subscription slice information, a PLMN ID (i.e., HPLMN ID) included in a UE ID (e.g., SUPI), mapping information received from the UE, an HPLMN S-NSSAI value (S-NSSAI 1 according to an embodiment of the present disclosure) received from the UE and through which the UE establishes a session, and a requested NSSAI received from the UE.

[0144] NSSF 1025 may determine a VPLMN S-NSSAI value mapped to a HPLMN S-NSSAI value received from AMF 360 or 1020 (e.g., a HPLMN S-NSSAI value included in the mapping information, or a HPLMN S-NSSAI value through which the UE establishes a session), and may be used in a VPLMN (i.e., a serving PLMN currently accessed by the UE). NSSF 1025 may determine an allowed NSSAI based on UE subscription slice information, an HPLMN S-NSSAI value included in the mapping information, a VPLMN S-NSSAI value determined by the NSSF, and a requested NSSAI value. The allowed NSSAI may be configured by at least one VPLMN S-NSSAI value available in the serving PLMN currently accessed by the UE. NSSF 1025 may send an NSSelection_Get response message to AMF 360 or 1020. The NSSelection_Get response message may include the allowed NSSAI determined by the NSSF and the mapping of the allowed NSSAI corresponding to the allowed NSSAI. Fig.10 1065) and 1070) in the process 7 of the registration acceptance message to the UE 1010. The registration acceptance message may include the allowed NSSAI received from the NSSF and the mapping of the allowed NSSAI. After receiving the registration acceptance message, the UE 1010 may store the mapping of the allowed NSSAI and the allowed NSSAI included in the registration acceptance message, and may use them to manage (create / modify / delete) the PDU session in the current registration area, and send or receive data.

[0145] According to an embodiment, in Figure 4 In the case of [HR embodiment 2] of process 9 in, the registration request message sent by UE 370 or 1010 to AMF 360 or 1020 via NG-RAN 365 or 1015 according to an embodiment of the present disclosure may not include slice related information. That is, the registration request message may not include the requested NSSAI.

[0146] When the ID of the UE (e.g., 5G-GUTI, GUTI, or SUPI) includes information allocated in the EPS, the AMF 360 or 1020 according to [HR Embodiment 2] can identify that the UE is a UE moved from the EPS. The AMF 360 or 1020 can obtain the PDN connection information configured by the UE in the EPS and the S-NSSAI information supported by the PDN connection from the UDM 1030. The AMF 360 or 1020 can allow the S-NSSAI supported by the PDN connection obtained from the UDM 310 or 1030 to be included in the allowed NSSAI of the registration accept message, and can send the message to the UE 370 or 1010.

[0147] According to an embodiment of the present disclosure, the operation of determining the mapping of the allowed NSSAI and the allowed NSSAI may be performed by the AMF 1020 instead of by the NSSF 1025. That is, Fig.10 Process 6 (operation 1060) in can be handled by internal operations of the AMF.

[0148] According to an embodiment of the present disclosure, the UE may Figure 4 The slice information included in the PCO form is stored in the message received in process 12. The slice information in the PCO form received by the UE may indicate the "S-NSSAI" value connected to the PDN connection, the "PLMN ID" using the corresponding S-NSSAI, and the "mapped slice" information. The UE may compare the received slice information with the slice policy information previously stored in the UE (e.g., UE routing selection policy (URSP), network slice selection policy (NSSP), UE local policy, etc.), and may determine whether the slice information matches the slice policy information. Table 1 represents an example of slice policy information stored in the UE.

[0149] Table 1

[0150] Application Identifier Slice Identifier (S-NSSAI) App ID #1 S-NSSAI 1 App ID #2 S-NSSAI 2 App ID #3 S-NSSAI 1,S-NSSAI 2 Match All S-NSSAI 3

[0151] The slice policy information stored in the UE includes the applications installed in the UE and the slice information used to use each application. For example, in the case of the UE's application ID #1, S-NSSAI 1 is used to provide services. A UE that intends to use application ID #1 can perform a registration process by accessing a 5G network. During the registration process, the UE can send a registration request message to the network, so the registration request message can include the slice information (S-NSSAI) that the UE intends to use in the form of requested NSSAI. During the registration process, the UE can receive an allowed NSSAI from the network, which is slice information that the UE can use by accessing the network. The UE can use the allowed NSSAI and slice policy information to allow S-NSSAI 1 to be included in the PDU session establishment request message when sending a PDU session establishment request message for application ID #1.

[0152] When the PCO received by the UE includes an "S-NSSAI" value (e.g., S-NSSAI 1) and a "PLMNID" using the corresponding S-NSSAI, i.e., HPLMN ID, the UE can use the slice policy information stored in the UE to identify the slice information mapped to the application used by the UE by accessing the EPS and generating a PDN connection.

[0153] When the application currently used by the UE is application ID #1, the slice identified based on the slice policy information stored in the UE may be S-NSSAI 1. In this case, it may be determined that the slice (S-NSSAI 1) identified based on the slice policy information stored in the UE matches the slice information (S-NSSAI 1) received using the PCO. Fig.10 When generating the requested NSSAI and the mapping of the requested NSSAI in process 1 (operation 1035) in , the UE may allow S-NSSAI 1 to be included in the requested NSSAI or the mapping of the requested NSSAI.

[0154] Alternatively, when the application currently used by the UE is application ID #2, the slice identified based on the slice policy information stored in the UE may be S-NSSAI 2. In this case, it may be determined that the slice identified based on the slice policy information stored in the UE (S-NSSAI 2) does not match the slice information (S-NSSAI 1) received using the PCO. Fig.10 When generating the requested NSSAI and the mapping of the requested NSSAI in process 1 (operation 1035) in , the UE may allow S-NSSAI 1 and S-NSSAI 2 to be included in the requested NSSAI or the mapping of the requested NSSAI.

[0155] When the PCO received by the UE includes an "S-NSSAI" value (e.g., S-NSSAI a), a "PLMNID" using the corresponding S-NSSAI, i.e., a VPLMN ID, and "mapped slice information" (e.g., {S-NSSAI 1, S-NSSAI a}), the UE can identify the slice information mapped to the application used by the UE by accessing EPS and generating a PDN connection through the slice policy information stored in the UE.

[0156] When the application currently used by the UE is application ID #1, the slice identified based on the slice policy information stored in the UE may be S-NSSAI 1. In this case, it may be determined that the slice identified based on the slice policy information stored in the UE (S-NSSAI 1) matches the slice information ({S-NSSAI 1, S-NSSAI a}) received using the PCO. Fig.10 When generating the requested NSSAI and the mapping of the requested NSSAI in process 1 (operation 1035), the UE may allow S-NSSAI a to be included in the requested NSSAI, and may allow {S-NSSAI 1, S-NSSAI a} to be included in the mapping of the requested NSSAI.

[0157] Alternatively, when the application currently used by the UE is application ID #2, the slice identified based on the slice policy information stored in the UE may be S-NSSAI 2. In this case, it may be determined that the slice identified based on the slice policy information stored in the UE (S-NSSAI 2) does not match the slice information ({S-NSSAI 1, S-NSSAI a}) received using the PCO. Fig.10 When generating the requested NSSAI and the mapping of the requested NSSAI in process 1 (operation 1035), the UE may allow S-NSSAI a and an unknown indication to be included in the requested NSSAI, and may allow {S-NSSAI 1, S-NSSAI a} and {S-NSSAI 2, unknown (or empty)} to be included in the mapping of the requested NSSAI.

[0158] Reference Fig.10 In process 2 (operation 1040), UE 1010 may send a registration request message to base station 1015 to register in the communication system. In process 3 (operation 1045), base station 1015 performs requested NSSAI identification and AMF selection based on slice information. In process 4 (operation 1050), base station 1015 may send a registration request message to AMF 1020 for access.

[0159] The registration request message sent in processes 2 and 4 (operations 1040, 1050) may include the requested NSSAI that UE 1010 intends to use after registering in the communication system. In process 1 (operation 1035), the requested NSSAI may be determined by UE 1010 based on the configured NSSAI. The requested NSSAI and the configured NSSAI may be configured by at least one S-NSSAI.

[0160] In process 5 (operation 1055), after receiving the registration request message 1050, the AMF 1020 may obtain UE subscription information from the UDM 1030. The UE subscription information may include the subscribed S-NSSAI of the UE 1010.

[0161] In process 6 (operation 1060), AMF 1020 can determine that based on the requested NSSAI received from UE 1010 in process 4 (operation 1050), the subscribed S-NSSAI received from UDM 1030 in process 5 (operation 1055), and the slice information available at the current location of UE 1010, UE 1010 can use the allowed NSSAI after registering in the communication system.

[0162] In process 6 (operation 1060), AMF 1020 may request NSSF 1025 to determine the allowed NSSAI. To this end, AMF 1020 may provide NSSF 1025 with the requested NSSAI received from UE 1010 in process 4 (operation 1050), the subscribed S-NSSAI received from UDM 1030 in process 5 (operation 1055), and the current location information of UE 1010. NSSF 1025 may determine the allowed NSSAI that UE 1010 can use after registering in the communication system based on the information received from AMF 1020 and the slice information available at the current location of UE 1010. NSSF 1025 may send the allowed NSSAI to AMF 1020.

[0163] At this time, if there are no slices that the UE can use after registration in the communication system, AMF 1020 and NSSF 1025 can generate a rejected S-NSSAI for the slices included in the requested NSSAI received from UE 1010 in process 4 (operation 1050), and can construct an allowed NSSAI by using the following various methods.

[0164] According to one or more embodiments, the AMF 1020 or the NSSF 1025 may identify the subscribed S-NSSAI of the UE 1010, and if the default S-NSSAI is included in the subscribed S-NSSAI, the AMF 1020 or the NSSF 1025 may allow the default S-NSSAI to be included in the allowed NSSAI. According to an embodiment, if the default S-NSSAI is not included in the subscribed S-NSSAI, the AMF 1020 or the NSSF 1025 may configure the subscribed S-NSSAI as "null", or may determine that the subscribed S-NSSAI is not sent to the UE 1010.

[0165] According to one or more embodiments, the AMF 1020 or the NSSF 1025 may configure the subscribed S-NSSAI as "NULL".

[0166] According to one or more embodiments, the AMF 1020 or the NSSF 1025 may determine that the subscribed S-NSSAI is not sent to the UE 1010.

[0167] After determining (or obtaining from NSSF 1025) the allowed NSSAI and the rejected S-NSSAI in process 6 (operation 1060), AMF 1020 may allow at least one of the allowed NSSAI and the rejected S-NSSAI to be included in the registration accept message sent to UE 1010 in process 7 (operation 1065). The registration accept message of process 7 (operation 1065) may be sent to UE 1010 via base station 1015 in process 8 (operation 1070).

[0168] Upon receiving the Registration Accept message in process 8 (operation 1070), the UE 1010 may identify the allowed NSSAI and / or rejected S-NSSAI included in the Registration Accept message, and may perform the following operations.

[0169] According to one or more embodiments, if the registration acceptance message received in process 8 (operation 1070) includes only the rejected S-NSSAI but not the allowed NSSAI, the UE 1010 may recognize that all requested slices requested by the UE from the network through processes 1, 2, and 4 (operations 1035, 1040, 1050) are rejected. Therefore, the UE 1010 may not send a PDU session request before receiving the allowed NSSAI from the network. Alternatively, when the UE sends a PDU session request until the allowed NSSAI is received from the network, the UE 1010 may not include the S-NSSAI. After receiving a PDU session request message that does not include the S-NSSAI, the network (e.g., SMF or AMF) may select a default S-NSSAI based on the subscription information of the UE 1010 and generate a PDU session.

[0170] According to one or more embodiments, when the registration acceptance message received in process 8 (operation 1070) includes a rejected S-NSSAI and the allowed NSSAI is configured as "empty", the UE 1010 may recognize that all requested slices requested by the UE from the network through processes 1, 2, and 4 (operations 1035, 1040, 1050) are rejected. Therefore, the UE 1010 may not send a PDU session request before receiving an allowed NSSAI from the network. Alternatively, when the UE sends a PDU session request until the allowed NSSAI is received from the network, the UE 1010 may not include the S-NSSAI. After receiving a PDU session request message that does not include the S-NSSAI, the network (e.g., SMF or AMF) may select a default S-NSSAI based on the subscription information of the UE 1010 and generate a PDU session.

[0171] According to one or more embodiments, if the rejected S-NSSAI of the registration acceptance message received in process 8 (operation 1070) includes all requested slices requested by UE 1010 from the network through processes 1, 2, and 4 (operations 1035, 1040, 1050) (i.e., all requested slices of the UE) and the allowed NSSAI includes the S-NSSAI, then UE 1010 can recognize that all requested slices requested by the UE from the network through processes 1, 2, and 4 (operations 1035, 1040, 1050) are rejected. In addition, UE 1010 can use the allowed NSSAI that UE 1010 has received in process 8 (operation 1070) until a new allowed NSSAI is received from the network in order to send a PDU session request. According to one embodiment, when the UE sends a PDU session request, UE 1010 can allow one S-NSSAI among the allowed NSSAIs received in process 8 (operation 1070) to be included in the PDU session request message.

[0172] Figure 7 The configuration of a base station in a wireless communication system according to an embodiment of the present disclosure is shown. Figure 7 The configuration shown in can be understood as the configuration of the base station 140, 245 or 340 of EPS or the base station 150, 255 or 365 of 5GS. The term "~ unit" or "~ device" used hereinafter may refer to a unit that processes at least one function or operation and may be implemented in hardware, software, or a combination of hardware and software.

[0173] See also Figure 7 The base station includes a wireless communication unit 710, a backhaul communication unit 720, a storage unit 730 and a control unit 740.

[0174] The wireless communication unit 710 performs functions for transmitting or receiving signals through a wireless channel. For example, the wireless communication unit 710 performs a conversion function between a baseband signal and a bit stream according to the physical layer standard of the system. For example, when transmitting data, the wireless communication unit 710 encodes and modulates the transmission bit stream to generate a composite symbol. In addition, when receiving data, the wireless communication unit 710 recovers the received bit stream by demodulating and decoding the baseband signal.

[0175] The wireless communication unit 710 up-converts the baseband signal into a radio frequency (RF) band signal and transmits the same signal through an antenna, and down-converts the RF band signal received through the antenna into a baseband signal. To this end, the wireless communication unit 710 may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), etc. In addition, the wireless communication unit 710 may include multiple transmission / reception paths. The wireless communication unit 710 may include at least one antenna array configured by a plurality of antenna elements.

[0176] In hardware, the wireless communication unit 710 may include a digital unit and an analog unit, and the analog unit may include multiple subunits according to operating power, operating frequency, etc. The digital unit may be implemented as at least one processor (eg, a digital signal processor (DSP)).

[0177] The wireless communication unit 710 may transmit or receive signals as described above. Therefore, all or part of the wireless communication unit 710 may be referred to as a "transmitter," "receiver," or "transceiver." Hereinafter, transmission and reception performed through a wireless channel may be understood to mean the above-mentioned processing performed by the wireless communication unit 710.

[0178] The backhaul communication unit 720 provides an interface for performing communication with other nodes in the 5GS network or EPS network. That is, the backhaul communication unit 720 converts a bit stream transmitted from the base station to another node, such as another access node, another base station, an upper node, or a core network into a physical signal, and converts a physical signal received from another node into a bit stream.

[0179] The storage unit 730 may store data, such as basic programs, applications, and configuration information for operating the base station. The storage unit 730 may be configured as a volatile memory, a nonvolatile memory, or a combination of a volatile memory and a nonvolatile memory. The storage unit 730 provides the stored data according to a request of the control unit 740.

[0180] The control unit 740 may control the overall operation of the base station. For example, the control unit 740 sends or receives a signal via the wireless communication unit 710 or the backhaul communication unit 720. In addition, the control unit 740 records data in the storage unit 730 and reads the data. The control unit 740 may perform the functions of the protocol stack required by the communication standard. According to other embodiments, the protocol stack may be included in the wireless communication unit 710. To this end, the control unit 740 may include at least one processor. According to multiple embodiments, the control unit 740 may include a function for network slice intercommunication. The function of network slice intercommunication is an instruction set or code stored in the storage unit 730, and may be an instruction / code at least temporarily residing in the control unit 740, a storage space for storing instructions / codes, or a partial circuit constituting the control unit 740.

[0181] According to multiple embodiments, the control unit 740 may receive a downlink NAS transmission including slice information for network slice intercommunication and a PDN connection acceptance message or a bearer establishment request message, and may control an RRC direct transfer message or an RRC connection reconfiguration message, which may include slice information to be sent to the UE. For example, the control unit 740 may control the base station to perform operations according to the above multiple embodiments.

[0182] Figure 8 The configuration of a UE in a wireless communication system according to an embodiment of the present disclosure is shown. Figure 8 The configuration shown in may be understood as the configuration of UE 155, 260 or 370. The term "~ unit" or "~ device" used hereinafter may refer to a unit that processes at least one function or operation and may be implemented in hardware, software, or a combination of hardware and software.

[0183] See also Figure 8 , the UE includes a communication unit 810, a storage unit 820 and a control unit 830.

[0184] The communication unit 810 operates a function for sending or receiving a signal through a wireless channel. For example, the communication unit 810 performs a conversion function between a baseband signal and a bit stream according to the physical layer standard of the system. For example, when sending data, the communication unit 810 encodes and modulates the transmission bit stream to generate a composite symbol. In addition, when receiving data, the communication unit 810 recovers the received bit stream by demodulating and decoding the baseband signal. The communication unit 810 up-converts the baseband signal to an RF band signal and sends the same signal through an antenna, and down-converts the RF band signal received by the antenna to a baseband signal. For example, the communication unit 810 may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, etc.

[0185] In addition, the communication unit 810 may include multiple transmit / receive paths. The communication unit 810 may include at least one antenna array configured by multiple antenna elements. In terms of hardware, the communication unit 810 may include digital circuits and analog circuits (e.g., radio frequency integrated circuits (RFIC)). The digital circuits and analog circuits may be implemented in a single package. In addition, the communication unit 810 may include multiple RF chains. The communication unit 810 may perform beamforming.

[0186] The communication unit 810 may include different communication modules to process signals in different frequency bands. In addition, the communication unit 810 may include multiple communication modules for supporting a variety of different radio access technologies. For example, different radio access technologies may include Bluetooth Low Energy (BLE), Wireless Fidelity (Wi-Fi), WiFi Gigabyte (WiGig), cellular networks (e.g., Long Term Evolution (LTE)), 5G networks, etc. In addition, different frequency bands may include ultra-high frequency (SHF) (e.g., 2.5Ghz and 5Ghz) bands and millimeter (mm) wave (e.g., 60GHz) bands.

[0187] The communication unit 810 may transmit or receive signals as described above. Therefore, all or part of the communication unit 810 may be referred to as a "transmitter," "receiver," or "transceiver." Hereinafter, transmission and reception performed through a wireless channel may be understood to mean the above-described processing performed by the communication unit 810.

[0188] The storage unit 820 may store data, such as basic programs, applications, and configuration information for operating the UE. The storage unit 820 may be configured as a volatile memory, a nonvolatile memory, or a combination of a volatile memory and a nonvolatile memory. The storage unit 820 provides the stored data according to a request of the control unit 830.

[0189] The control unit 830 can control the overall operation of the UE. For example, the control unit 830 sends or receives a signal via the communication unit 810. In addition, the control unit 830 records data in the storage unit 820 and reads the data. The control unit 830 can perform the functions of the protocol stack required by the communication standard. To this end, the control unit 830 may include at least one processor and a microprocessor, or may be a part of a processor. The communication unit 810 and the part of the control unit 830 may be referred to as a communication processor (CP). According to multiple embodiments, the control unit 830 may include a function for supporting network slicing. The function for supporting network slicing is an instruction set or code stored in the storage unit 820, and may be an instruction / code that at least temporarily resides in the control unit 830, a storage space for storing instructions / codes, or a partial circuit constituting the control unit 830.

[0190] According to multiple embodiments, the control unit 830 may control the UE to access the MME 420 via the E-UTRA base station 415 to exchange signaling messages with the PGW-C 430 located in the EPS and establish a PDN connection, and when the PDN connection is established, the UE 410 may be controlled to send uplink data to the PGW-U 435 or receive downlink data from the PGW-U 435. Specifically, the control unit 830 may receive an RRC connection reconfiguration message or an RRC direct transfer message from the base station, and may store the S-NSSAI, that is, the slice information included in the message, and the PLMN ID using the corresponding S-NSSAI. For example, the control unit 830 may control the UE to perform operations according to the above-mentioned multiple embodiments.

[0191] Fig. 9 The configuration of a core network entity in a wireless communication system according to an embodiment of the present disclosure is shown. Fig. 9 The configuration shown in can be understood as having Figures 1 to 3 The present invention relates to a configuration of a device for performing at least one function among HSS+UDM 110, 210 and 310; PCF+PCRF 115, 215, 220 and 315; SMF+PGW-C 120, 225 and 320; UPF+PGW-U 125, 230 and 325; SGW 130, 235 and 330; MME 135, 240 and 335; AMF 145, 250 and 360; UPF 355; v-SMF 350 and vFPC 345. The term “~ unit” or “~ device” used hereinafter may refer to a unit that processes at least one function or operation and may be implemented by hardware, software, or a combination of hardware and software.

[0192] See also Fig. 9 The core network entity includes a communication unit 910, a storage unit 920 and a control unit 930.

[0193] The communication unit 910 provides an interface for performing communication with other devices in the network. That is, the communication unit 910 converts the bit stream sent from the core network entity to different devices into a physical signal, and converts the physical signal received from different devices into a bit stream. That is, the communication unit 910 can send or receive a signal. Therefore, the communication unit 910 can be referred to as a "modem", "transmitter", "receiver" or "transceiver". The communication unit 910 can allow the core network entity to communicate with other devices or systems via a backhaul connection (e.g., a wired backhaul or a wireless backhaul) or via a network.

[0194] The storage unit 920 stores data such as basic programs, applications, and configuration information for core network entity operations. The storage unit 920 may be configured as a volatile memory, a nonvolatile memory, or a combination of a volatile memory and a nonvolatile memory. The storage unit 920 provides the stored data according to a request of the control unit 930.

[0195] The control unit 930 controls the entire operation of the core network entity. For example, the control unit 930 sends or receives a signal via the communication unit 910. In addition, the control unit 930 records data in the storage unit 920 and reads the data. To this end, the control unit 930 may include at least one processor. According to multiple embodiments, the control unit 930 may include functions for supporting network slicing. The functions for supporting network slicing may be implemented by an instruction set or code stored in the storage unit 920, and may be instructions / codes that at least temporarily reside in the control unit 930, a storage space for storing instructions / codes, or a partial circuit constituting the control unit 930.

[0196] According to multiple embodiments, the control unit 930 can: receive a create session request message; send a Nudm_SDM_Get request message; receive a Nudm_SDM_Get response message; compare the received subscribed S-NSSAI with the S-NSSAI information provided by the SMF-PGW-C itself for selecting the S-NSSAI to be used; and control the function of enabling the S-SNSSAI to be included in the create session response message and sending it to the UE, and the control unit 930 can perform control so that the core network entity performs operations according to the above-mentioned multiple embodiments.

[0197] The methods according to the embodiments disclosed in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0198] When these methods are implemented by software, a computer-readable storage medium for storing one or more programs (software modules) may be provided. One or more programs stored in the computer-readable storage medium may be configured to be run by one or more processors in an electronic device. At least one program includes instructions that cause the electronic device to perform the method according to the embodiments disclosed in the claims or specification of the present disclosure.

[0199] Programs (software modules, software) may be stored in non-volatile memory, including random access memory and flash memory, read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), magnetic disk storage devices, compact disk-ROM (CD-ROM), digital versatile disk (DVD), other types of optical storage devices or magnetic tapes. Alternatively, programs may be stored in a memory configured by any combination of part or all of such programs. In addition, a plurality of such memories may be included in an electronic device.

[0200] In addition, the program can be stored in a connectable storage device, which can be accessed through a communication network such as the Internet, an intranet, a local area network (LAN), a wide area network (WAN), and a storage area network (SAN) or a combination thereof. Such a storage device can access the electronic device executing the embodiments of the present disclosure through an external port. In addition, a separate storage device on a communication network can access the electronic device executing the embodiments of the present disclosure.

[0201] In the above detailed embodiments of the present disclosure, the components included in the present disclosure are expressed in singular or plural form according to the detailed embodiments presented. However, for ease of description, the singular form or plural form suitable for the presented situation is selected, and the present disclosure is not limited to a single element or multiple elements thereof. Further, multiple elements expressed in the specification can be configured as a single element, or a single element expressed in the specification can be configured as multiple elements.

[0202] While the present disclosure has been shown and described with reference to several embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the spirit and scope of the present disclosure as defined by the appended claims and their equivalents.

Claims

1. A method performed by a user equipment UE in a wireless communication system, the method comprising: Sending a packet data network PDN connection request message to a mobility management entity MME; receiving information from a network entity including a packet data network gateway control plane entity PGW-C and a session management function SMF, the information being about first network slice selection assistance information NSSAI, wherein the first NSSAI is selected by the network entity from at least one subscribed NSSAI associated with the UE, and in a home domain routed roaming case, the first NSSAI is a HPLMN NSSAI; Sending a registration request message to an access and mobility management function AMF entity, where the registration request message includes a requested NSSAI including the first NSSAI; as well as A registration accept message is received from the AMF entity, the registration accept message including an allowed NSSAI, the allowed NSSAI including a second NSSAI mapped to the first NSSAI.

2. The method according to claim 1, wherein: The second NSSAI is for the Visited Public Land Mobile Network VPLMN.

3. The method according to claim 2, wherein: The second NSSAI is determined by the network slice selection function NSSF entity.

4. The method according to claim 1, wherein: The MME supports the Evolved Packet System, EPS, and the AMF entity supports the fifth generation wireless system, 5GS.

5. The method according to claim 1, wherein: The first NSSAI is received via the protocol configuration option PCO.

6. The method according to claim 1, further comprising: It is determined whether the first NSSAI matches a user equipment routing policy URSP rule.

7. A user equipment UE in a wireless communication system, the UE comprising: Transceiver; as well as At least one processor configured to: Sending a packet data network PDN connection request message to a mobility management entity MME via a transceiver; receiving, via a transceiver, information from a network entity including a packet data network gateway control plane entity PGW-C and a session management function SMF, the information being about first network slice selection assistance information NSSAI, wherein the first NSSAI is selected by the network entity from at least one subscribed NSSAI associated with the UE, and in a home domain routed roaming case, the first NSSAI is a HPLMN NSSAI; Sending a registration request message to an access and mobility management function AMF entity via the transceiver, where the registration request message includes a requested NSSAI including the first NSSAI; as well as A registration accept message is received from the AMF entity via the transceiver, the registration accept message including an allowed NSSAI, the allowed NSSAI including a second NSSAI mapped to the first NSSAI.

8. The UE according to claim 7, wherein: The second NSSAI is for the Visited Public Land Mobile Network VPLMN.

9. The UE according to claim 8, wherein: The second NSSAI is determined by the network slice selection function NSSF entity.

10. The UE according to claim 7, wherein: The MME supports the Evolved Packet System, EPS, and the AMF entity supports the fifth generation wireless system, 5GS.

11. The UE according to claim 7, Therein a first NSSAI is received via a protocol configuration option PCO.

12. The UE of claim 7, wherein the at least one processor is further configured to: It is determined whether the first NSSAI matches a user equipment routing policy URSP rule.

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