KR20210115927A - Method and apparatus for managing protocol data unit session in wireless communication system - Google Patents

Abstract

The present invention relates to a method for user equipment operation in a network slicing-supporting wireless communication system. The method includes: a step of transmitting a service request message piggybacking a request message on a protocol data unit (PDU) session to an access and mobility function; a step of receiving a service accept message on the service request message; and a step of setting a PDU session based on the accept message on the PDU session piggybacked to the service accept message. The service request message further includes a request type field for request message type instruction related to the PDU session.

Description

Method and apparatus for PDU session management in a wireless communication system

The present invention relates to a method and apparatus for managing a protocol data unit (PDU) session (PDU session), and more particularly, to a method of operating a terminal for managing a PDU session in a wireless communication system supporting network slicing. will be.

The communication system may include a core network, a base station (eg, a macro base station, a small base station, a relay, etc.), and user equipment (UE). In a communication system supporting 4G communication technology (eg, long term evolution (LTE) technology), the core network includes a mobility management entity (MME), a serving gateway (SGW), a packet data network (PDN) gateway (PGW), etc. may include In a communication system supporting 5G communication technology (eg, new radio (NR) technology), the core network may include an access and mobility function (AMF), a user plane function (UPF), a session management function (SMF), and the like. have.

Communication between the base station and the UE is a variety of radio access technology (RAT) (eg, 4G communication technology, 5G communication technology, wireless broadband (WiBro) technology, wireless local area network (WLAN) technology, wireless personal area network (WPAN) technology etc.) can be performed. The base station may be connected to the core network through a wired backhaul or a wireless backhaul. For example, the base station may transmit data and control information received from the terminal to the core network through a wired backhaul or a wireless backhaul. In addition, the base station may receive data and control information from the core network through a wired backhaul or a wireless backhaul.

Meanwhile, a network slicing technique may be applied to a communication system. The purpose of the network slicing technology is to efficiently optimize and use resources of a communication system by minimizing capital expenditure (CAPEX) and operating expenditure (OPEX). Accordingly, methods for optimally managing a PDU (protocol data unit) session of network slicing in a communication system will be needed.

An object of the present invention for solving the above problems is to provide a method and apparatus for managing a protocol data unit (PDU) session in a wireless communication system supporting network slicing.

In order to achieve the above object, a method of operating a user equipment (UE) in a wireless communication system supporting network slicing according to a first embodiment of the present invention for achieving the above object is a request message related to a protocol data unit (PDU) session. Transmitting a service request (service request) message to piggyback (piggyback) to an access and mobility function (AMF); receiving a service accept message for the service request message; and establishing a PDU session based on a PDU session acknowledgment message that is piggybacked to the service acknowledgment message, wherein the service request message is S-NSSAI (single S-NSSAI) indicating network slicing applied to the PDU session. -network slice selection assistance information) field may be further included.

Here, the operating state of the UE, it is characterized in that the RRC (radio resource control) idle (RRC idle) state, by receiving the service acknowledgment message, the operating state can be switched to the RRC connected (RRC connected) state have.

Here, the service request message may further include a request type field for indicating the type of the request message related to the PDU session.

Here, the type of the request message regarding the PDU session is one of a PDU session establishment request message, a PDU session modification request message, and a PDU session release request message. can be

Here, the service request message may further include a PDU session identifier (ID) indicating the PDU session of the UE.

Here, the service request message may further include a data network name (DNN) field indicating a data network (DN) that is the establishment target of the PDU session.

Here, the step of establishing the PDU session comprises setting the PDU session to which the DN indicated by the DNN field and the network slicing indicated by the S-NSSAI field are applied, and the request type field indicates It may be set to one of establishment, change, and release.

As a method of operating a first communication node in a wireless communication system supporting network slicing in another embodiment of the present invention for achieving the above object, a request message related to a PDU (protocol data unit) session is piggybacked ( receiving a service request (service request) message for piggybacking from a second communication node; generating a service accept message for the service request message; generating an acknowledgment message related to the PDU session in response to the request message related to the PDU session; transmitting the service acknowledgment message for piggybacking the acknowledgment message about the PDU session; and establishing a PDU session with the second communication node based on an acknowledgment message regarding the PDU session, wherein the service request message is S-NSSAI (single-NSSAI) indicating network slicing applied to the PDU session. network slice selection assistance information) field may be further included.

Here, the first communication node may be an access and mobility function (AMF), and the second communication node may be a user equipment (UE).

Here, the operation state of the second communication node is characterized in that the RRC (radio resource control) idle (RRC idle) state, the service approval message, the operation state of the second communication node RRC connected (RRC connected) ) can be instructed to switch to the state.

Here, the service request message further includes a request type field for indicating the type of the request message related to the PDU session, and the type of the request message related to the PDU session is a PDU session establishment request (PDU). It may be one of a session establishment request message, a PDU session modification request message, and a PDU session release request message.

here. determining a session management function (SMF) to request a session management (SM) context based on the service request message; sending an SM context request message to the SMF; and receiving an SM context grant message from the SMF, wherein the service grant message may be generated based on the SM context grant message.

Here, the determining of the SMF may include determining the SMF based on information indicated by the S-NSSAI field.

Here, the service request message may further include a data network name (DNN) field indicating a data network (DN) that is a target of establishing the PDU session, and the SMF may be determined based on information indicated by the DNN field. .

A first communication node in a wireless communication system supporting network slicing according to a third embodiment of the present invention for achieving the above object, a processor; communicating with the processor electronically memory; and instructions stored in the memory, wherein when the instructions are executed by the processor, the instructions cause the first communication node to piggyback a request message regarding a protocol data unit (PDU) session. sending a service request message to piggyback to the second communication node; receive a service accept message for the service request message; operative to cause establishment of a PDU session based on an acknowledgment message related to a PDU session piggybacked to the service acknowledgment message, wherein the service request message is S-NSSAI (single S-NSSAI) indicating network slicing applied to the PDU session -network slice selection assistance information) field, and may operate to cause establishment of the PDU session based on information indicated by the S-NSSAI field.

Here, the first communication node may be a user equipment (UE), and the second communication node may be an access and mobility function (AMF).

Here, the operation state of the first communication node is characterized in that the RRC (radio resource control) idle (RRC idle) state, and receives the service approval message, the operation state is changed to the RRC connected (RRC connected) state operable to cause a transition.

Here, the service request message may further include a request type field for indicating the type of the request message related to the PDU session.

Here, the type of the request message regarding the PDU session is one of a PDU session establishment request message, a PDU session modification request message, and a PDU session release request message. can be

Here, the service request message further includes a data network name (DNN) field indicating a data network (DN) that is an establishment target of the PDU session, and establishing the PDU session based on information indicated by the DNN field can act to cause

According to the present invention, a terminal in a wireless network idle state in a 5G mobile communication system establishes, modifies, and releases a PDU (protocol data unit) session within a message for It can supplement IE (information element). Accordingly, it is possible to ensure a smooth protocol flow in a communication system supporting network slicing, maximize the effect of reducing signaling overhead, and optimize the use efficiency of network resources/functions.

1 is a conceptual diagram illustrating a first embodiment of a communication system.
2 is a block diagram showing a first embodiment of a communication node constituting a communication system.
3 is a conceptual diagram illustrating a first embodiment of a communication system including a core network supporting network slicing.
4 is a conceptual diagram illustrating a first embodiment of a network slice in a communication system.
5 is a conceptual diagram illustrating a first embodiment of an operation of communication nodes establishing a protocol data unit (PDU) session in a communication system.
6 is a conceptual diagram illustrating a second embodiment of operations of communication nodes establishing a PDU session in a communication system.

Since the present invention can have various changes and can have various embodiments, specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to specific embodiments, and it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

Terms such as first, second, etc. may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component. and/or includes a combination of a plurality of related listed items or any of a plurality of related listed items.

When a component is referred to as being “connected” or “connected” to another component, it is understood that the other component may be directly connected or connected to the other component, but other components may exist in between. it should be On the other hand, when it is said that a certain element is "directly connected" or "directly connected" to another element, it should be understood that no other element is present in the middle.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. does not

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. In describing the present invention, in order to facilitate the overall understanding, the same reference numerals are used for the same components in the drawings, and duplicate descriptions of the same components are omitted.

A communication system to which embodiments according to the present invention are applied will be described. The communication system to which the embodiments according to the present invention are applied is not limited to the contents described below, and the embodiments according to the present invention can be applied to various communication systems. Here, a communication system may be used in the same sense as a communication network (network).

Throughout the specification, a terminal is a mobile station (mobile station, MS), a mobile terminal (MT), an advanced mobile station (AMS), a high reliability mobile station (HR-MS) ), subscriber station (SS), portable subscriber station (PSS), access terminal (AT), user equipment (terminal), machine type communication device (machine type communication device, MTC device) and the like, and may include all or some functions of MT, MS, AMS, HR-MS, SS, PSS, AT, UE, and the like.

In addition, the base station (base station, BS) is an advanced base station (advanced base station, ABS), a high reliability base station (high reliability base station, HR-BS), a Node B (node B), an advanced node B (evolved node B, eNodeB), an access point (AP), a radio access station (RAS), a base transceiver station (BTS), a mobile multihop relay (MMR)-BS, a relay serving as a base station station, RS), a relay node (RN) serving as a base station, an advanced relay station (ARS) serving as a base station, and a high reliability relay station (HR) serving as a base station -RS), small base station [femto base station (femto BS), home node B (home node B, HNB), home eNodeB (HeNB), pico base station (pico BS), macro base station (macro BS), micro base station (micro BS) ), etc.], etc., may include all or part of the functions of ABS, NodeB, eNodeB, AP, RAS, BTS, MMR-BS, RS, RN, ARS, HR-RS, small base station, etc. have.

The base station configures one or more cells, and the terminal establishes an RRC connection with at least one cell of the corresponding base station. Here, the cell with which the RRC connection is established is referred to as a serving cell.

1 is a conceptual diagram illustrating a first embodiment of a communication system.

1, the communication system 100 is a plurality of communication nodes (110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2, 130-3, 130-4, 130-5, 130-6). Here, the communication system 100 may be referred to as a “communication network”. Each of the plurality of communication nodes may support at least one communication protocol. For example, each of the plurality of communication nodes may include a code division multiple access (CDMA)-based communication protocol, a wideband CDMA (WCDMA)-based communication protocol, a time division multiple access (TDMA)-based communication protocol, and a frequency division multiple (FDMA)-based communication protocol. access) based communication protocol, OFDM (orthogonal frequency division multiplexing) based communication protocol, OFDMA (orthogonal frequency division multiple access) based communication protocol, SC (single carrier)-FDMA based communication protocol, NOMA (non-orthogonal multiple) access)-based communication protocol, space division multiple access (SDMA)-based communication protocol, and the like may be supported. Each of the plurality of communication nodes may have the following structure.

2 is a block diagram showing a first embodiment of a communication node constituting a communication system.

Referring to FIG. 2 , the communication node 200 may include at least one processor 210 , a memory 220 , and a transceiver 230 connected to a network to perform communication. In addition, the communication node 200 may further include an input interface device 240 , an output interface device 250 , a storage device 260 , and the like. Each component included in the communication node 200 may be connected by a bus 270 to communicate with each other.

The processor 210 may execute a program command stored in at least one of the memory 220 and the storage device 260 . The processor 210 may mean a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which methods according to embodiments of the present invention are performed. Each of the memory 220 and the storage device 260 may be configured as at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory 220 may be configured as at least one of a read only memory (ROM) and a random access memory (RAM).

Referring back to FIG. 1 , the communication system 100 includes a plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2, a plurality of user equipment ) (130-1, 130-2, 130-3, 130-4, 130-5, 130-6). Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 may form a macro cell. Each of the fourth base station 120-1 and the fifth base station 120-2 may form a small cell. The fourth base station 120-1, the third terminal 130-3, and the fourth terminal 130-4 may belong to the coverage of the first base station 110-1. The second terminal 130-2, the fourth terminal 130-4, and the fifth terminal 130-5 may belong to the coverage of the second base station 110-2. The fifth base station 120-2, the fourth terminal 130-4, the fifth terminal 130-5, and the sixth terminal 130-6 may belong within the coverage of the third base station 110-3. . The first terminal 130-1 may belong to the coverage of the fourth base station 120-1. The sixth terminal 130-6 may belong to the coverage of the fifth base station 120-2.

Here, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, 120-2 is a NodeB (NodeB), an advanced NodeB (evolved NodeB), a base transceiver station (BTS), A radio base station, a radio transceiver, an access point, an access node, a road side unit (RSU), a radio remote head (RRH), a transmission point (TP) , a transmission and reception point (TRP), a relay node, and the like. Each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, 130-6 is a terminal, an access terminal, a mobile terminal, It may be referred to as a station, a subscriber station, a mobile station, a portable subscriber station, a node, a device, and the like.

A plurality of communication nodes (110-1, 110-2, 110-3, 120-1, 120-2, 130-1, 130-2, 130-3, 130-4, 130-5, 130-6) Each may support cellular (cellular) communication (eg, long term evolution (LTE), LTE-A (advanced), etc. defined in the 3rd generation partnership project (3GPP) standard). Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may operate in different frequency bands or may operate in the same frequency band. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be connected to each other through an ideal backhaul or a non-ideal backhaul, and the ideal backhaul Alternatively, information may be exchanged with each other through a non-ideal backhaul. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be connected to a core network (not shown) through an ideal backhaul or a non-ideal backhaul. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 transmits a signal received from the core network to the corresponding terminals 130-1, 130-2, 130-3, 130 -4, 130-5, 130-6), and the signal received from the corresponding terminal (130-1, 130-2, 130-3, 130-4, 130-5, 130-6) is transmitted to the core network can be sent to

Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may support OFDMA-based downlink transmission, and SC-FDMA-based uplink (uplink) transmission. ) can support transmission. In addition, each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 transmits multiple input multiple output (MIMO) (eg, single user (SU)-MIMO, MU (multi user)-MIMO, massive MIMO, etc.), coordinated multipoint (CoMP) transmission, carrier aggregation transmission, transmission in an unlicensed band, device to device, D2D ) communication (or ProSe (proximity services)) may be supported. Here, each of the plurality of terminals 130-1, 130-2, 130-3, 130-4, 130-5, 130-6 is the base station 110-1, 110-2, 110-3, and 120-1. , 120-2) and corresponding operations, and operations supported by the base stations 110-1, 110-2, 110-3, 120-1, and 120-2 may be performed.

For example, the second base station 110-2 may transmit a signal to the fourth terminal 130-4 based on the SU-MIMO method, and the fourth terminal 130-4 may transmit a signal based on the SU-MIMO method. A signal may be received from the second base station 110 - 2 . Alternatively, the second base station 110-2 may transmit a signal to the fourth terminal 130-4 and the fifth terminal 130-5 based on the MU-MIMO scheme, and the fourth terminal 130-4. and each of the fifth terminals 130 - 5 may receive a signal from the second base station 110 - 2 by the MU-MIMO method. Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 may transmit a signal to the fourth terminal 130-4 based on the CoMP scheme, and the fourth The terminal 130-4 may receive signals from the first base station 110-1, the second base station 110-2, and the third base station 110-3 by the CoMP method. Each of the plurality of base stations 110-1, 110-2, 110-3, 120-1, and 120-2 includes the terminals 130-1, 130-2, 130-3, 130-4, 130-5, 130-6) and a signal may be transmitted/received based on the carrier aggregation method. Each of the first base station 110-1, the second base station 110-2, and the third base station 110-3 coordinates D2D communication between the fourth terminal 130-4 and the fifth terminal 130-5. (coordination), each of the fourth terminal 130-4 and the fifth terminal 130-5 is D2D communication by the respective coordination of the second base station 110-2 and the third base station 110-3 can be performed.

3 is a conceptual diagram illustrating a first embodiment of a communication system including a core network supporting network slicing.

3, the communication system 300 includes a core network 310, an access network (AN) (eg, a radio access network (RAN)) 320, a data network (DN) 330 and a UE ( user equipment) 340 . The core network 310 includes an access and mobility management function (AMF) 310-1, a user plane function (UPF) 310-2, a session management function (SMF) 310-3, and an authentication server function (AUSF). (310-4), NEF (network exposure function) (310-5), NRF (network repository function) (310-6), PCF (policy control function) (310-7), UDM (user data management) (310) -8), an application function (AF) 310-9, and a network slice selection function (NSSF) 310-10. Here, the NSSF 310-10 may be used to support selection of a network slice. In the embodiments below, the network slice may indicate a network slice instance (NSI) or a network slice subnet instance (NSSI).

The network functions 310-1 to 310-10 constituting the core network 310 may be performed by one or more physical devices. Alternatively, the network functions 310-1 to 310-10 constituting the core network 310 may be implemented as instances or virtual functions executed in a physical device.

The core network 310 may be classified into a control plane and a user plane. The control plane may be classified into a common control plane and a slice specific control plane. AMF 310 - 1 , UPF 310 - 2 , AUSF 310 - 4 , UDM 310 - 8 , and NSSF 310 - 10 may belong to a common control plane. The SMF 310-3, NEF 310-5, NRF 310-6, and PCF 310-7 may belong to a common control plane or a slice-specific control plane. Network functions belonging to a common control plane may be shared by a plurality of NSIs or a plurality of NSSIs. Network functions belonging to a slice specific control plane may be dedicated for a specific NSI or a specific NSSI.

The AMF 310-1 may perform the following functions.

- Termination of RAN CP (control plane) interface (N2)

- NAS (non-access stratum) interface (N1) termination, NAS encryption and integrity protection

- Registration management

- connection management

- Reachability management

- Mobility management

- Lawful intercept of AMF events and interfaces of L1 systems

- Transparent proxy for SM message routing

- access authentication

- access authorization

- SEA (security anchor function)

- SCM (security context management)

Meanwhile, in the communication system 300 , communication between the AMF 310-1 and the NSSF 310-10 may be performed through an Ns interface, and the AMF 310-1 interworks with the NSSF 310-10 to network A slicing-related operation may be performed. For example, NSI or NSSI may be selected based on the operation between the AMF 310-1 and the NSSF 310-10.

When the network slicing technique is applied to the communication system 300 , network resources/functions may be set as one independent network slice according to a required service. Accordingly, the network operator may set a network resource/function specialized for a service or a user as a network slice, and may provide the network slice to a user who has requested the corresponding service. In addition, software defined networking (SDN)/network function virtualization (NFV) technology may be applied to the communication system 300 , and accordingly, network resources/functions may be virtualized.

Next, methods for establishing a session of a terminal for network slicing in a communication system will be described. Even when a method (eg, transmission or reception of a signal) performed in a first communication node among communication nodes is described, a corresponding second communication node is a method (eg, a method corresponding to the method performed in the first communication node) For example, reception or transmission of a signal) may be performed. That is, when the operation of the UE is described, the corresponding base station may perform the operation corresponding to the operation of the UE. Conversely, when the operation of the base station is described, the corresponding UE may perform the operation corresponding to the operation of the base station.

4 is a conceptual diagram illustrating a first embodiment of a network slice in a communication system.

Referring to FIG. 4 , a network slice may be a logical network composed of network resources/functions necessary to provide specific network performance/characteristics to a user. The network slice may be located in the RAN 420 and the core network (CN) 430 . The NSI may be a set of network resources/functions that provide an intended network slice service according to a template.

A plurality of NSIs may be allocated to each of the UEs 410 - 1 and 420 - 2 . For example, NSI #1 to 2 may be allocated to UE #1 410-1, and NSI #3 to 4 may be allocated to UE #2 410-2. NSIs #1 and #3 may be configured to provide an enhanced mobile broadband (eMBB) service, and NSIs #2 and #4 may be configured to provide an Internet of things (IoT) service. NSIs #1 to 4 may be configured in the RAN 420 and CN 430 , and each of NSIs #1 to 4 may include a plurality of NSSIs.

NSI #1 may be composed of a RAN slice (eg, a network resource/function constituting the RAN 420) and a CN slice (eg, a network resource/function constituting the CN 430). A CN slice may include a common control network function (CCNF), a slice-specific control network function (SCNF), user plane functions (UPFs), and other network functions (NF). Each of NSIs #1 to 4 may include instances supporting one or more network functions for providing a required service. An instance supporting a network function may be referred to as a network function instance (NFI).

Each of the UEs 410 - 1 and 410 - 2 may access a plurality of NSIs through one RAN 420 . In this case, NSI #1~2 may share some functions of the control plane (eg, AMF, NSSF), and NSI #3~4 may share some functions of the control plane (eg, AMF, NSSF). can share A function of a control plane shared by NSIs assigned to one UE 410 - 1 and 410 - 2 may be referred to as CCNF. AMF and NSSF included in CCNF may be shared by one or more NSIs according to a policy of a network operator.

The NSSF may be a network function having NSI topology information for a public land mobile network (PLMN). For example, the NSSF may check availability of a set of active NSI(s) corresponding to the registration area, and may be an entry point that can access a specific NSI. In addition, in order to select a target NSI based on at least one of a serving mobile virtual network operator (MVNO), an over the top (OTT) provider, a location of the UE, and a time window, the NSSF is a single A slice-level service mapping operation for network slice selection assistance information may be supported.

Here, the NSI may be selected from an NSI pool for a specific S-NSSAI for load balancing and redundancy. Slice level control rules may be set by a network operator. In addition, the NSSF may support a statistic collection function for slice selection for the management system of the serving PLMN. In the operation between NSSF and AMF, the following parameters may be considered.

The input parameter of the NSSF may include an accepted (accepted) S-NSSAI. In addition, the input parameter of the NSSF may include at least one of a past NSI list associated with the UEs 410 - 1 and 410 - 2 and a serving registration area of the UEs 410 - 1 and 410 - 2 .

The output parameter of the NSSF may include information (eg, NSI ID (identifier)) of the NSI corresponding to the approved S-NSSAI. Here, the NSI may be a newly selected NSI based on the approved S-NSSAI. In addition, the output parameter of the NSSF may include at least one of an Internet protocol (IP) address or fully qualified domain name (FQDN) of a new serving AMF, and an IP address or FQDN of a serving NRF selected for NSI.

In addition, the PLMN may include a provisioned NSI and NRF for discovery/selection of a network function. In order for the NRF to support the discovery/selection operation of the network function with or without network slicing, the input parameter of the NSSF may include a logical network identifier as well as the type of the network function. The logical network identifier may indicate an NSI ID or a serving PLMN.

5 is a conceptual diagram illustrating a first embodiment of the operation of communication nodes establishing a PDU session in a communication system.

Referring to FIG. 5 , a UE 510 of a wireless communication network may access a service through an access network, and the UE 510 performs a registration procedure and a protocol data unit (PDU) session establishment procedure. can be carried out separately. The UE 510 performing the registration procedure may generate a registration request message. The registration request message may include information listed in Table 1.

Referring to Table 1, the registration request message may include a request NSSAI field (or information element (IE)) corresponding to a network slice requesting registration. The UE 510 may transmit a registration request message to the AMF 530 through the (R)AN 520 (S510).

The AMF 530 may receive a registration request message from the UE 510 through the (R)AN 520 (S510). The AMF 530 determines whether or not authorization for the NSSAI requested by the terminal through a query with other entities 550 of the core network, such as preset context information and/or NSSF, NRF, UDM, etc. It can be confirmed (S520). The AMF 530 may check whether authentication is performed in units of S-NSSAI (S520).

The AMF 530 may generate a registration accept message for approving the UE 510 registration request based on the result of the authentication procedure. The registration approval message may include information about the NSSAI listed in Table 2.

Referring to Table 2, the registration approval message may include allowed NSSAI (allowed NSSAI) information, and may further include rejected NSSAI (rejected NSSAI) and configured NSSAI (configured NSSAI) information. The allowed NSSAI may mean an NSSAI accepted by the core network, the rejected NSSAI may mean an NSSAI rejected by the core network, and the set NSSAI may mean an NSSAI that can be supported by the core network. The AMF 530 may transmit a registration acknowledgment message to the UE 510 through the (R)AN 520 (S530).

The UE 510 may receive a registration approval message from the AMF 530 through the (R)AN 520 (S530). The UE 510 may complete the network registration procedure based on the NSSAI information included in the registration grant message. The UE 510 may transmit a registration complete message to the AMF 530 via the (R)AN 520 . A radio resource control (RRC) layer of the UE 510 that has completed the registration procedure and the RRC layer of the base station and the core network may be in a connected state (RRC_CONNECTED).

The UE 510 that has completed the registration procedure may perform a PDU session establishment procedure. A UE performing a PDU session establishment procedure may configure a network slice. A protocol for establishing a PDU session may be a non-access stratum (NAS) protocol. The NAS protocol may include a mobility management (MM) protocol and a session management (SM) protocol. The MM protocol may be a protocol for managing initial access, authentication, connection, and mobility of the UE 510 , and the SM protocol may be a protocol for managing a PDU session of the UE 510 .

The UE 510 may generate a PDU session establishment request message for requesting establishment of a PDU session based on information obtained from the registration approval message. The PDU session establishment request message may be an SM protocol message. However, in the standard specification, the SM message may not be transmitted alone. Accordingly, the UE 510 may generate a UL NAS transport message that is a message of the MM protocol. The UL NAS delivery message may include an uplink message, and the UL NAS delivery message may further include the information in Table 3.

Referring to Table 3, the UL NAS delivery message may include a payload container type field. The payload container type field may be a field for piggybacking a message related to a PDU session (eg, a message related to PDU session establishment, change, and release). The UL NAS delivery message may include an S-NSSAI field. The S-NSSAI field may be an indicator of a network slice to be configured when establishing a PDU session. The UL NAS delivery message may include a request type field, and the request type field may indicate the type of the SM message. The type of the SM message is one of an initial request (initial request), an existing PDU session request (existing PDU session), an initial emergency request (initial emergency request), an existing emergency PDU session request (existing emergency PDU session) and a change request (modification request). can be The UL NAS delivery message may further include a DNN field, and the DNN field may indicate the name of a DN to establish a PDU session with the UE 510 .

The UE 510 may transmit a UL NAS transmission message through the (R)AN 520 ( S550 ), and may piggyback the PDU session establishment request message to the UL NAS transmission message and transmit it to the AMF 530 . (S550).

The AMF 530 may receive the UL NAS delivery message from the UE 510 through the (R)AN 520 (S550). In addition, the AMF 530 may receive a PDU session establishment request message that is piggybacked on the UL NAS delivery message (S550). The AMF 530 establishes a PDU session with the UE based on the information (eg, S-NSSAI, DNN, and request type information, etc.) included in the PDU session establishment request message of the UE 510 . can decide

If information on the S-NSSAI is not obtained from the PDU session establishment request message, the AMF 530 may determine the initial S-NSSAI. And when information on S-NSSAI is obtained from the PDU session establishment request message but information on DNN is not obtained, the AMF 530 may determine an initial DN based on the S-NSSAI.

The AMF 530 may generate a session management context request (SM context request) message for requesting generation of a session management context (SM context). The session management context request message may include information such as DNN, S-NSSAI(s), PDU session ID, AMF 530 ID, and request type. The AMF 530 may transmit the generated session management context request message to the SMF 540 .

The SMF 540 may receive a session management context request message from the AMF 530 . The SMF 540 may create a session management context based on the received session management context request message. The SMF 540 may generate a session management context response message including the created session management context. The SMF 540 may transmit the generated session management context response message to the AMF 530 .

The SMF 540 may send and receive a message to the UPF for requesting a session connection (N4 session establishment request) and a message for responding to the N4 session connection request (N4 session establishment response). For example, the SMF 540 may transmit a session connection request message generated based on information included in the PDU session establishment request message to the UPF. In addition, the SMF 540 may receive a response message to the session connection request message from the UPF.

The SMF 540 may generate a message including information about the reference point between the AMF 530 and the UE 510 and the reference point between the AMF 530 and the base station. A message including information about the reference point is a PDU session ID, session management information of the N1 reference point between the AMF 530 and the UE 510, and the session of the N2 reference point between the AMF 530 and (R) AN 520 . May contain management information.

The session management information of the N2 reference point may include information of the (R)AN 520 to be connected to the AMF 530 . Session management information of the N2 reference point includes PDU session ID, Quality of Service (QoS) profile, QFI (QoS flow identifier), CN tunnel information, S-NSSAI obtained from allowed NSSAI, Session-AMBR, It may include a PDU session type, an indicator for ensuring the integrity of the UE 510, and a maximum data rate.

The AMF 530 may generate a PDU session establishment accept message that is a response to the PDU session establishment request of the UE 510 . PDU session establishment acknowledgment message is QoS rule (QoS rule), QoS flow level (QoS flow level), QoS parameter (QoS parameter), determined SSC mode (selected SSC mode), S-NSSAI(s), DNN, assigned IPv4 Address, interface indicator, Session-AMBR (aggregate maximum bit-rate), the determined type of PDU session, QoS Timer, and information about the P-CSCF (proxy-call session control function) determined by the SMF (540) may be included. have. However, in the standard specification, the SM message may not be transmitted alone. Accordingly, the AMF 530 may generate a DL NAS transport message that is a message of the MM protocol. The DL NAS delivery message may include a downlink message.

The AMF 530 may transmit the DL NAS delivery message to the UE 510 through the (R)AN 520 (S560), and piggyback the generated PDU session establishment approval message to the DL NAS delivery message to the UE 510 ) can be transmitted (S560).

The UE 510 may receive a DL NAS delivery message from the AMF 530 through the (R)AN 520 (S560), and may receive a PDU session establishment approval message piggybacked to the DL NAS delivery message. (S560). The UE 510 may establish a PDU session based on the PDU session establishment approval message (S570). The UE 510 may generate a PDU resource session response message that is a response to the PDU resource session request message received from the AMF 530 . The PDU resource session response message may include the ID of the PDU session and session management information of the N2 reference point. The session management information of the N2 reference point may further include AN tunnel information. The AN tunnel information may include information about the network address of the N3 reference point tunnel connected to the PDU session. The UE 510 may transmit the generated PDU resource session response message to the AMF 530 .

6 is a conceptual diagram illustrating a second embodiment of operations of communication nodes establishing a PDU session in a communication system.

Referring to FIG. 6 , a UE 510 in a wireless communication network may access a service through an access network. The UE 510 may be in an RRC connected state by completing the registration procedures S510 to S540 of FIG. 5 . However, when the UE 510 does not perform a separate operation for more than a preset time after being registered in the network, the (R)AN 520 releases the RRC layer connection of the UE 510 (RRC release) can do. Alternatively, the radio connection between the UE 510 and the (R) AN 520 may fail (radio link failure, RLF). When the RRC connection is released or RLF occurs, the RRC state of the UE 510 may be switched to an idle state (RRC_IDLE) (S610).

The UE 510 may generate a PDU session establishment request message requesting establishment of a PDU session. The PDU session establishment request message may be an SM protocol message. The UE 510 in the RRC idle state may switch the state of the UE 510 to the RRC connected state before establishing a PDU session. That is, the UE 510 may establish a PDU session after converting the RRC state to the connected state. The UE 510 may generate a service request message that is a message of the MM protocol for converting the RRC state to the connected state. The service request message may include an uplink message, and the service request message may further include information of Table 4.

Referring to Table 4, the service request message may include a NAS message container field, and the NAS message container field is for piggybacking a message related to a PDU session (eg, a message related to PDU session establishment, change, and release). It can be a field.

However, the service request message defined in the standard may not include a field indicating some information necessary for establishment of a PDU session. For example, the service request message may not include a field indicating S-NSSAI. Accordingly, the AMF 530 receiving the service request message may establish a PDU session with the UE 510 based on the preset initial S-NSSAI and/or the initial DNN.

In order for the AMF 530 receiving the service request message to establish a PDU session according to the request of the UE 510, the service request message may further include information for establishing the PDU session. That is, the service request message may further include the information of Table 5.

Referring to Table 5, the service request message may include a request type field, and the request type field may indicate the type of the SM message (eg, PDU session establishment request message, etc.). The type of the SM message may be one of a PDU session establishment request, a PDU session establishment change request, and a PDU session release request.

When the type of the SM message is a PDU session establishment request or a PDU session establishment change request, the service request message may further include an S-NSSAI field, and the S-NSSAI field may indicate the network slice of the PDU session to be configured. have. When the type of the SM message is a PDU session establishment request or a PDU session establishment change request, the service request message may further include a DNN field, and the DNN field indicates the name of a DN to establish a PDU session with the UE 510. can

The UE 510 may transmit a service request message through the (R)AN 520 (S620), and may piggyback the PDU session establishment request message to the service request message and transmit it to the AMF 530 (S620). ).

The AMF 530 may receive a service request message from the UE 510 through the (R)AN 520 (S620). In addition, the AMF 530 may receive a PDU session establishment request message that is piggybacked on the service request message (S620). The AMF 530 establishes a PDU session with the UE based on the information (eg, S-NSSAI, DNN, and request type information, etc.) included in the PDU session establishment request message of the UE 510 . can decide

The AMF 530 may generate an SM context request message. The SM context request message may include information such as DNN, S-NSSAI(s), PDU session ID, AMF 530 ID, and request type. S-NSSAI(s), request type, and DNN information of the SM context request message may be determined based on the service request message. The AMF 530 may transmit the generated session management context request message to the SMF 540 (S630).

The SMF 540 may receive a session management context request message from the AMF 530 (S630). The SMF 540 may create a session management context based on the received session management context request message. The SMF 540 may generate a session management context response message including the created session management context. The SMF 540 may transmit the generated session management context response message to the AMF 530 (S640).

The SMF 540 may establish a session with the UPF. For example, the SMF 540 may transmit a session connection request message generated based on information (eg, request type and DNN information) included in the PDU session establishment request message to the UPF. In addition, the SMF 540 may receive a response message to the session connection request message from the UPF.

The SMF 540 may generate a message including information about the reference point between the AMF 530 and the UE 510 and the reference point between the AMF 530 and the base station. A message including information about the reference point is a PDU session ID, session management information of the N1 reference point between the AMF 530 and the UE 510, and the session of the N2 reference point between the AMF 530 and (R) AN 520 . May contain management information.

The session management information of the N2 reference point may include information of the (R)AN 520 to be connected to the AMF 530 . The session management information of the N2 reference point may include information such as PDU session ID, QoS profile, QFI, CN tunnel information, S-NSSAI(s), Session-AMBR, and PDU session type.

The AMF 530 may generate a PDU session establishment acknowledgment message that is a response to the PDU session establishment request of the UE 510 . The PDU session establishment acknowledgment message includes QoS-related information (eg, QoS rules, QoS flow level, QoS parameters, determined SSC mode, S-NSSAI(s), DNN, assigned IPv4 address, interface indicator, Session-AMBR, determined The PDU session type, QoS timer, and information about the P-CSCF determined by the SMF 540 may be included, and the AMF 530 may generate a service accept message that is a message of the MM protocol. The service acknowledgment message may include a downlink message.

The AMF 530 may transmit the service acknowledgment message to the UE 510 through the (R)AN 520 (S650), and piggyback the generated PDU session establishment acknowledgment message to the service acknowledgment message to the UE 510. It can be transmitted (S650).

The UE 510 may receive a service acknowledgment message from the AMF 530 through the (R)AN 520 (S650), and may receive a PDU session establishment acknowledgment message that is piggybacked on the DL NAS delivery message ( S650). Upon receiving the service approval message, the UE 510 may switch the RRC operation state from the idle state to the RRC connected state (S660). The UE 510 in the RRC connection state may establish a PDU session based on the PDU session establishment approval message (S670).

The methods according to the present invention may be implemented in the form of program instructions that can be executed by various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions recorded on the computer-readable medium may be specially designed and configured for the present invention, or may be known and available to those skilled in the art of computer software.

Examples of computer-readable media include hardware devices specially configured to store and carry out program instructions, such as ROM, RAM, flash memory, and the like. Examples of program instructions include not only machine language codes such as those generated by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate as at least one software module to perform the operations of the present invention, and vice versa.

Although it has been described with reference to the above embodiments, it will be understood by those skilled in the art that various modifications and changes can be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. will be able

Claims (20)

A method of operating a user equipment (UE) in a wireless communication system supporting network slicing, comprising:
transmitting a service request message for piggybacking a request message regarding a protocol data unit (PDU) session to an access and mobility function (AMF);
receiving a service accept message for the service request message; and
Establishing a PDU session based on an acknowledgment message related to the PDU session piggybacked to the service acknowledgment message,
The service request message is
The method of claim 1, further comprising a single-network slice selection assistance information (S-NSSAI) field indicating network slicing applied to the PDU session. The method according to claim 1,
The operating state of the UE is,
It is characterized in that the RRC (radio resource control) idle (RRC idle) state,
Upon receiving the service acknowledgment message, the UE switches the operating state to an RRC connected state. The method according to claim 1,
The service request message is
Further comprising a request type (request type) field for indicating the type of the request message related to the PDU session, the operating method of the UE. 4. The method according to claim 3,
The type of the request message for the PDU session is,
One of a PDU session establishment request message, a PDU session modification request message, and a PDU session release request message, an operating method of a UE. 4. The method according to claim 3,
The service request message is
The method of operation of the UE, further comprising a PDU session ID (identifier) indicating the PDU session of the UE. 5. The method according to claim 4,
The service request message is
The method of operation of a UE further comprising a data network name (DNN) field indicating a data network (DN) that is the establishment target of the PDU session. 7. The method of claim 6,
The step of establishing the PDU session comprises:
It is characterized in that the PDU session to which the DN indicated by the DNN field and the network slicing indicated by the S-NSSAI field is applied is established,
As indicated by the request type field, one of establishment, change, and release is set. A method of operating a first communication node in a wireless communication system supporting network slicing, comprising:
receiving, from a second communication node, a service request message for piggybacking a request message regarding a protocol data unit (PDU) session;
generating a service accept message for the service request message;
generating an acknowledgment message related to the PDU session in response to the request message related to the PDU session;
transmitting the service acknowledgment message for piggybacking the acknowledgment message about the PDU session; and
establishing a PDU session with the second communication node based on an acknowledgment message regarding the PDU session;
The service request message is
The method of claim 1, further comprising a single-network slice selection assistance information (S-NSSAI) field indicating network slicing applied to the PDU session. 9. The method of claim 8,
The method of operating a first communication node, characterized in that the first communication node is an access and mobility function (AMF) and the second communication node is a user equipment (UE). 9. The method of claim 8,
The operating state of the second communication node is,
It is characterized in that the RRC (radio resource control) idle (RRC idle) state,
The service approval message is
Instructing to switch the operating state of the second communication node to an RRC connected (RRC connected) state, the operating method of the first communication node. 9. The method of claim 8,
The service request message is
Further comprising a request type (request type) field for indicating the type of the request message related to the PDU session,
The type of the request message for the PDU session is,
One of a PDU session establishment request message, a PDU session modification request message, and a PDU session release request message, the operating method of the first communication node. 9. The method of claim 8,
determining a session management function (SMF) to request a session management (SM) context based on the service request message;
sending an SM context request message to the SMF; and
Receiving an SM context grant message from the SMF,
The service approval message is
Generated based on the SM context grant message, the operating method of the first communication node. 13. The method of claim 12,
The step of determining the SMF,
The method of operating the first communication node, characterized in that the SMF is determined based on the information indicated by the S-NSSAI field. 13. The method of claim 12,
The service request message is
Further comprising a data network name (DNN) field indicating a data network (DN) that is the establishment target of the PDU session,
Determining the SMF based on the information indicated by the DNN field, the operating method of the first communication node. A first communication node in a wireless communication system supporting network slicing, comprising:
processor;
a memory in electronic communication with the processor; and
Including instructions stored in the memory,
When the instructions are executed by the processor, the instructions cause the first communication node to
sending a service request message for piggybacking a request message about a protocol data unit (PDU) session to the second communication node;
receive a service accept message for the service request message;
operative to cause establishment of a PDU session based on an acknowledgment message relating to a PDU session piggybacked to the service acknowledgment message;
The service request message is
Further comprising a single-network slice selection assistance information (S-NSSAI) field indicating network slicing applied to the PDU session;
and cause to establish the PDU session based on information indicated by the S-NSSAI field. 16. The method of claim 15,
The first communication node, characterized in that the first communication node is a user equipment (UE) and the second communication node is an access and mobility function (AMF). 16. The method of claim 15,
The operating state of the first communication node is,
It is characterized in that the RRC (radio resource control) idle (RRC idle) state,
a first communication node operative to receive the service grant message and cause transition of the operational state to an RRC connected state. 16. The method of claim 15,
The service request message is
The first communication node further comprising a request type field for indicating a type of a request message regarding the PDU session. 19. The method of claim 18,
The type of the request message for the PDU session is,
One of a PDU session establishment request message, a PDU session modification request message, and a PDU session release request message, the first communication node. 16. The method of claim 15,
The service request message is
Further comprising a data network name (DNN) field indicating a data network (DN) that is the establishment target of the PDU session,
and cause to establish the PDU session based on the information indicated by the DNN field.

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