Method and apparatus for providing access service control functions in a wireless communication system

Abstract

The disclosure relates to a communication method and system for a fifth generation (5G) communication system that supports higher data rates than a fourth generation (4G) system and Internet of Things (IoT) technology. The disclosure is applicable to intelligent services based on 5G communication technology and IoT-related technology, such as smart home, smart building, smart city, smart car, connected car, health care, digital education, smart retail, security and safety services. According to the embodiment, the disclosure proposes a method in which an old AMF in a wireless communication system identifies a registration of a UE in an AMF that does not support ATSSS and releases a MAPDU session when the UE is registered (a registration procedure), and a method in which the UE identifies the registration and releases the MAPDU session.

Description

Technical Field

[0001] This disclosure relates to a method and apparatus for providing access service control (Access Service Control, Handover, and Derouting (ATSSS)) functions in a wireless communication system. Background Technology

[0002] To meet the increased demand for wireless data services since the deployment of fourth-generation (4G) communication systems, efforts have been made to develop improved fifth-generation (5G) or pre-5G communication systems. 5G or pre-5G communication systems are also referred to as "beyond 4G networks" or "post-LTE systems." 5G communication systems are considered to be implemented in higher frequency (mmWave) bands (e.g., the 60GHz band) to achieve higher data rates. To reduce radio wave propagation loss and increase transmission distance, beamforming, massive MIMO, full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and large antenna technologies have been discussed for 5G communication systems. Furthermore, system network improvements are being developed in 5G communication systems based on advanced small cells, cloud radio access networks (RAN), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, mobile networks, cooperative communication, coordinated multipoint (CoMP), and receiver interference cancellation. In 5G systems, hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC) have also been developed as advanced coding modulation (ACM), as well as filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) as advanced access technologies.

[0003] The Internet, a human-centric network of connections where humans generate and consume information, is now evolving into the Internet of Things (IoT), where distributed entities, such as things, exchange and process information without human intervention. The Internet of Everything (IoE) has emerged as a combination of IoT technology and big data processing technology connected to cloud servers. Because IoT implementation requires technological elements such as sensing technology, wired / wireless communication and network infrastructure, service interface technology, and security technology, sensor networks, machine-to-machine (M2M) communication, and machine-type communication (MTC) have recently been studied. This IoT environment can provide intelligent Internet technology services that create new value for human life by collecting and analyzing data generated between connected things. Through the convergence and combination of existing information technology (IT) and various industrial applications, IT can be applied to a wide range of fields, including smart homes, smart buildings, smart cities, smart cars or connected cars, smart grids, healthcare, smart devices, and advanced medical services.

[0004] Consistent with this, various attempts have been made to apply 5G communication systems to IoT networks. For example, technologies such as sensor networks, MTC, and M2M communication can be implemented through beamforming, MIMO, and array antennas. Cloud RAN, as an application of the aforementioned big data processing technologies, can also be considered an example of the integration of 5G and IoT technologies.

[0005] In 5G communication systems, connections to various access networks such as New Radio (NR), wireless LAN, and wired LAN are supported. Access Service Control (ATSSS) technology is currently under development and is capable of transmitting services using different access networks.

[0006] The above information is presented as background information only to aid in understanding this disclosure. No determination or assertion is made regarding whether any of the foregoing content is applicable as prior art to this disclosure. Summary of the Invention

[0007] [Technical Issues]

[0008] To use ATSSS in a communication system conforming to current 3GPP standards, the User Equipment (UE), Access and Mobility Management Function (AMF), Session Management Function (SMF), and User Plane Function (UPF) must support this function. When a UE registers in a new AMF due to movement after establishing one or more Multiple Access Packet Data Unit (MA PDU) sessions through the old AMF, the MA PDU sessions used for the corresponding access must be released if the new AMF does not support ATSSS. Currently, there is no technology for releasing MA PDU sessions; this disclosure proposes a method and apparatus to solve this problem.

[0009] [Solution to the problem]

[0010] In a wireless communication system according to an embodiment, when a user equipment (UE) registers with an access and mobility management function (AMF) that does not support ATSSS (registration process), a normally registered AMF can recognize the registration and release the old MAPDU session, or the UE can recognize the registration and release the old MA PDU session.

[0011] According to one aspect of this disclosure, a method is provided performed by a first Access and Mobility Management Function (AMF) entity in a wireless communication system. The method includes: receiving a first message including information relating to supported features of a second AMF entity; identifying, based on the information, whether the second AMF entity supports Access Service Control, Handover, Demultiplexing (ATSSS) functionality; if the second AMF entity does not support ATSSS functionality, sending a second message to the second AMF entity including a User Equipment (UE) context, wherein the UE context does not include a context for a Multiple Access Packet Data Unit (MA PDU) session; and sending a third message to a Session Management Function (SMF) entity requesting the release of an MA PDU session, wherein the MA PDU session is released based on the third message.

[0012] In this method, the first message is received from the second AMF entity, and the first message is a message used to request the transfer of the UE context stored in the first AMF entity to the second AMF entity.

[0013] In this method, the first message is provided by a Network Resource Library Function (NRF) entity, the first AMF entity is the source AMF entity associated with the handover, and the second AMF entity is the target AMF entity associated with the handover.

[0014] Furthermore, the method includes receiving a fourth message from the second AMF entity notifying of a successful switchover, wherein the third message is sent after the fourth message is received.

[0015] In this method, the first message includes the network function (NF) profile of the second AMF entity, and the NF profile includes the aforementioned information.

[0016] According to another aspect of this disclosure, a first Access and Mobility Management Function (AMF) entity is provided in a wireless communication system. The first AMF entity includes: a transceiver configured to transmit and receive signals; and a controller coupled to the transceiver and configured to: receive a first message including information relating to supported features of a second AMF entity; based on the information, identify whether the second AMF entity supports Access Service Control, Handover, and Detachment (ATSSS) functions; if the second AMF entity does not support ASSSS functions, send a second message to the second AMF entity including a User Equipment (UE) context, wherein the UE context does not include a context for a Multiple Access Packet Data Unit (MA PDU) session; and send a third message to a Session Management Function (SMF) entity requesting the release of an MA PDU session, wherein the MA PDU session is released based on the third message.

[0017] According to another aspect of this disclosure, a method is provided performed by a Session Management Function (SMF) entity in a wireless communication system. The method includes: receiving, based on information relating to supported features of a second AMF entity, a first message from a first Access and Mobility Management Function (AMF) entity requesting the release of a Multiple Access Packet Data Unit (MA PDU) session; and releasing the MA PDU session based on the first message, wherein the information indicates whether the second AMF entity supports Access Service Control, Handover, Detachment, and Access Control Service (ATSSS) functions; and wherein, if the second AMF entity does not support ASSSS functions based on the information, a second message including a User Equipment (UE) context is transmitted to the second AMF entity, and the UE context does not include context for the MA PDU session.

[0018] According to another aspect of this disclosure, a Session Management Function (SMF) entity in a wireless communication system is provided. The SMF entity includes: a transceiver configured to transmit and receive signals; and a controller coupled to the transceiver and configured to: receive, based on information relating to supported features of a second AMF entity, a first message from a first Access and Mobility Management Function (AMF) entity requesting the release of a Multiple Access Packet Data Unit (MA PDU) session; and release the MA PDU session based on the first message, wherein the information indicates whether the second AMF entity supports Access Service Control, Handover, Demultiplexing (ATSSS) functions, and wherein, if the second AMF entity does not support ASSS functions based on the information, a second message including a User Equipment (UE) context is transmitted to the second AMF entity, and the UE context does not include context for the MA PDU session.

[0019] [Beneficial effects of the invention]

[0020] This disclosure supports various schemes for releasing MA PDU sessions that are not supported by 3GPP 5G systems. Based on embodiments of this disclosure, when a UE registers in an AMF that does not support ATSSS, older MA PDU sessions can be effectively released. Attached Figure Description

[0021] To gain a more complete understanding of this disclosure and its advantages, reference is now made to the following description in conjunction with the accompanying drawings, wherein like reference numerals denote like parts:

[0022] Figure 1 The architecture of a system that supports ATSSS in a 3GPP 5G system is shown.

[0023] Figure 2 This disclosure illustrates the problem it seeks to solve;

[0024] Figure 3A sequence diagram of a process is shown in which the old AMF releases the old MA PDU session based on the updated SM context service;

[0025] Figure 4 A sequence diagram of a process is shown in which the old AMF releases the old MA PDU session based on the release SM context service;

[0026] Figure 5 A sequence diagram is shown of the process for releasing an old MAPDU session based on a PDU session release request that includes a specific request type of the UE;

[0027] Figure 6 A sequence diagram is shown of the procedure for releasing an old MA PDU session using a UE-based PDU session release request;

[0028] Figure 7 The sequence diagram illustrates the process by which a UE releases an old MA PDU session via local release;

[0029] Figure 8 This diagram illustrates the sequence of steps taken when the old AMF releases the old MAPDU session based on the updated SM context service when the AMF changes due to the N2 handover.

[0030] Figure 9 This demonstrates a method for releasing the MA PDU session after the old AMF recognizes that the UE has successfully registered in the new AMF when the UE requests to register in an AMF that does not support ATSSS;

[0031] Figure 10 A method is shown in which, when the UE's AMF is changed to a new AMF that does not support ATSSS during an N2-based handover, the old AMF (S-AMF) receives a message from the new AMF indicating that the UE's handover was successfully performed, and then releases the MA PDU session;

[0032] Figure 11 A block diagram illustrating the structure of a UE according to an embodiment is shown; and

[0033] Figure 12 A block diagram of the structure of higher nodes according to an embodiment is shown. Detailed Implementation

[0034] Before proceeding with the following detailed description, it may be advantageous to define certain words and phrases used in this patent document: the phrases “comprising” and “including” and their derivatives mean including but not limited to; the phrase “or” is inclusive, referring to and / or; the phrases “associated with” and “associated with” and their derivatives may mean including, being included, interconnected with, containing, being contained, connected to or connected to, linked to or connected to, able to communicate with, cooperate with, interleaved, juxtaposed, adjacent, bound to or bound to, having, having the properties of, etc.; and the phrase “controller” means any device, system or part thereof that controls at least one operation, such device may be implemented in hardware, firmware or software, or at least a combination of the above. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether local or remote.

[0035] Furthermore, the various functions described below can be implemented or supported by one or more computer programs, each computer program being formed by computer-readable program code and contained in a computer-readable medium. The terms "application program" and "program" refer to one or more computer programs, software components, instruction sets, procedures, functions, objects, classes, instances, associated data, or portions thereof suitable for implementation in appropriate computer-readable program code. The phrase "computer-readable program code" includes any type of computer code, including source code, object code, and executable code. The phrase "computer-readable medium" includes any type of media accessible by a computer, such as read-only memory (ROM), random access memory (RAM), hard disk drive, optical disc (CD), digital video disc (DVD), or any other type of storage. "Non-transitory" computer-readable media excludes wired, wireless, optical, or other communication links that transmit transient electrical or other signals. A non-transitory computer-readable medium includes media that can permanently store data, as well as media that can store data and subsequently rewrite it, such as rewritable optical discs or erasable storage devices.

[0036] Definitions of certain words and phrases are provided throughout this patent document, and those skilled in the art will understand that, in many cases, if not most, such definitions apply to the existing and future use of the words and phrases defined therein.

[0037] The following discussion Figures 1 to 12 The various embodiments used to describe the principles of this disclosure in this patent document are merely exemplary and should not be construed as limiting the scope of this disclosure in any way. Those skilled in the art will understand that the principles of the invention can be implemented in any suitably arranged system or device.

[0038] In describing embodiments of this disclosure, descriptions related to techniques well-known in the art and not directly associated with this disclosure will be omitted. The purpose of omitting unnecessary descriptions is to prevent confusion with the main ideas of this disclosure and to convey them more clearly.

[0039] For the same reason, some elements may be exaggerated, omitted, or shown schematically in the accompanying drawings. Furthermore, the dimensions of each element do not perfectly reflect the actual dimensions. In the drawings, identical or corresponding elements have the same reference numerals.

[0040] The advantages and features of this disclosure, as well as the ways in which they are implemented, will be apparent from the embodiments described in detail below with reference to the accompanying drawings. However, this disclosure is not limited to the embodiments set forth below, but can be implemented in a variety of different forms. The following embodiments are provided only to fully disclose this disclosure and to inform those skilled in the art of its scope, and this disclosure is limited only by the scope of the appended claims. Throughout the specification, the same or similar reference numerals denote the same or similar elements.

[0041] Here it will be understood that each box of a flowchart, and combinations of boxes in a flowchart, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in one or more flowchart boxes. These computer program instructions can also be stored in a computer-usable or computer-readable storage medium that can direct the computer or other programmable data processing apparatus to operate in a particular manner, such that the instructions stored in the computer-usable or computer-readable storage medium produce an article of writing including instruction means for implementing the functions specified in the flowchart boxes. The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus, thereby producing a computer-implemented process, such that the instructions, which execute on the computer or other programmable apparatus, provide steps for implementing the functions specified in one or more flowchart boxes.

[0042] Furthermore, each box in the flowchart can represent a module, segment, or section of code, which includes one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions recorded in the boxes may occur sequentially. For example, two boxes shown consecutively may actually execute substantially simultaneously, or these boxes may sometimes execute in reverse order, depending on the functions involved.

[0043] As used herein, a “cell” refers to a software or hardware element that performs a predetermined function, such as a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC). However, a “cell” is not always limited to software or hardware. A “cell” can be configured to be stored in addressable memory or to execute one or more processors. Therefore, a “cell” includes, for example, software elements, object-oriented software elements, class elements or task elements, processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and parameters. The elements and functions provided by a “cell” can be combined into a smaller number of elements or “cells”, or divided into a larger number of elements or “cells.” Furthermore, elements and “cells” can be implemented as one or more CPUs within a playback device or a secure multimedia card.

[0044] This disclosure relates to methods and apparatus for supporting various services in a wireless communication system. Specifically, this disclosure describes a technique for providing access service control (Access Service Control, Switching, Demultiplexing (ATSSS)) functions in a wireless communication system.

[0045] As used in the following description, for convenience, terms for identifying access nodes, terms relating to network entities or network functions (NFs), terms relating to messages, terms relating to interfaces between network entities, terms relating to various identifying information, etc., are used by way of example. Therefore, this disclosure is not limited to the terms used below, and other terms relating to the subject matter having equivalent technical meaning may be used.

[0046] Figure 1 This illustrates a system architecture for supporting Access Service Control, Switching, Decentralization (ATSSS) in a 3GPP 5G system. Through ATSSS functionality, it is possible to... Figure 1 The Protocol Data Unit (PDU) (or Packet Data Unit) session shown anchors multiple paths (e.g., 3GPP Access 110 and non-3GPP Access 120) between User Plane Function (UPF) 104 and User Equipment (UE) 101 to perform service transmission. Meanwhile, for ATSSS to be used, UE 101, Access and Mobility Management Function (AMF) 102, Session Management Function (SMF) 103, and User Plane Function (UPF) 104 should support ATSSS.

[0047] Figure 2 The problem that will be addressed by this disclosure is shown. Figure 2The illustration shows a scenario where UE 210 has already established one or more MA PDU sessions with the old AMF 211, and then registers UE 210 with the new AMF 212 due to UE movement 200. When the new AMF 212 does not support ATSSS (i.e., an AMF that cannot use ATSSS), the old AMF 211 sends the context used for the old MA PDU sessions to the new AMF via UE context transfer, as shown by reference numeral 202. At this time, although the new AMF does not support ATSSS, unexpected operations may occur due to the existence of unreleased MA PDU sessions if they are not released. Therefore, in order to operate MA PDU sessions effectively, the MA PDU sessions used for the corresponding access must be released. Currently, there is no technology for releasing MA PDU sessions; this disclosure proposes a method and apparatus to solve this problem.

[0048] Figure 3 The method described in the embodiment is to release the MA PDU session by the old AMF via UpdateSMContext when the UE is registered in a new AMF that does not support ATSSS.

[0049] refer to Figure 3 In step 301, the UE may send a registration request message to the new AMF in order to perform the registration process for the new AMF (steps 1 to 3). Specifically, in step 1, the UE may send an Access Node (AN) message including the registration request message to the AN, and in step 2, the AN that receives the AN message may determine the AMF, and in step 3, it sends an N2 message including the registration request message to the determined AMF (i.e., the new AMF).

[0050] In step 304, the new AMF can send a Namf_Communication_UEContextTransfer request message to the old AMF. At this time, the corresponding message may include the access type and the UE's supported features. When the new AMF does not support ATSSS, the supported features do not include the MA PDU session support indicator.

[0051] When it is determined that the new AMF does not support ATSSS, the old AMF identifies in step 305 whether a MA PDU session of the access type received in step 304 exists in the UE context. If a received MA PDU session of the access type exists, the old AMF can perform operations for the SMF to release the MA PDU session of that access type. Specifically, the old AMF can send an Nsmf_PDUSession_UpdateSMContext request message to the SMF. The Nsmf_PDUSession_UpdateSMContext request message may include information about the SM context ID, a release instruction, and the access type used for the MA PDU session release. Here, the SM context ID is the context identifier of the MA PDU session ID that should be released locally and should be shared between the AMF and SMF. The release instruction is an indicator indicating the release request, and the access type used for the MA PDU session release is the access type that should be released.

[0052] At this point, the old AMF can determine whether the new AMF supports ATSSS as follows: 1) the MA PDU session support indicator in the support feature field or parameter included in the request message in step 304, 2) the MA PDU session support indicator in the support feature of the new AMF's NF profile stored in the Network Resource Library Function (NRF), and 3) the local configuration of the AMF.

[0053] Upon receiving the message from AMF in step 305, SMF determines in step 306, through its local policy, whether to release only the access type used to receive MA PDU sessions mapped to SM context IDs or to release all accesses. SMF can then instruct UPF, based on the determination result, whether to release MA PDU sessions for only one access or for all accesses.

[0054] In step 307, the SMF sends an Nsmf_PDUSession_UpdateSMContext response message to the old AMF, which includes the request result from step 305.

[0055] Even if the response message from the SMF includes a message requesting that it be sent to the UE or AN, in step 308, the old AMF does not perform operations such as sending. The old AMF responds to the request message in step 304 by sending the UE context to the new AMF.

[0056] At this point, the old AMF will not insert the context of the MA PDU session that was successfully released from the message from the SMF into the UE context to be sent to the new AMF.

[0057] In step 309, the remaining registration process for the UE is performed. If a MAPDU session context that is not present in the UE context received in step 308 exists in the UE, the UE can locally release the MAPDU session that exists only in the UE through the synchronization process with the new AMF.

[0058] Figure 4 The illustration shows a method by which the old AMF releases the MA PDU session via ReleaseSMContext when the UE is registered in a new AMF that does not support ATSSS, according to an embodiment.

[0059] Reference Figure 4 In step 401, the UE may send a registration request to the new AMF in order to perform the registration process for the new AMF (steps 1 to 3). Specifically, in step 1, the UE may send an Access Node (AN) message including a registration request message to the AN, and in step 2, the AN that receives the AN message may determine the AMF, and in step 3, it may send an N2 message including a registration request message to the determined AMF (i.e., the new AMF).

[0060] In step 404, the new AMF can send a Namf_Communication_UEContextTransfer request message to the old AMF. At this time, the corresponding message may include the access type and the UE's supported features. When the new AMF does not support ATSSS, the supported features do not include the MA PDU session support indicator.

[0061] When it is determined that the new AMF does not support ATSSS, the old AMF identifies in step 405 whether a MA PDU session of the access type received in step 404 exists in the UE context. If a received MA PDU session of the access type exists, the old AMF can perform operations for the SMF to release the MA PDU session of that access type.

[0062] Specifically, the old AMF can send an Nsmf_PDUSession_Release request message to the SMF. The Nsmf_PDUSession_Release request message can include information about the SM context ID and the access used for the MA PDU session release. Here, the SM context ID is the context identifier of the MA PDU session ID that should be released locally and should be shared between the AMF and SMF. The access used for the MA PDU session release is the access type that should be released.

[0063] At this point, the old AMF can determine whether the new AMF supports ATSSS as follows: 1) the MA PDU session support indicator in the support features included in the request message in step 404, 2) the MA PDU session support indicator in the support features of the new AMF's NF profile stored in the Network Resource Library Function (NRF), and 3) the local configuration of the AMF.

[0064] Upon receiving the message from AMF in step 405, SMF determines in step 406, through its local policy, whether to release only the access type used to receive MA PDU sessions mapped to SM context IDs or to release all access. SMF can then instruct UPF, based on the determination result, whether to release only the access used for MA PDU sessions or to release all access.

[0065] In step 407, SMF sends an Nsmf_PDUSession_ReleaseSMContext response that includes the result of the request in step 405.

[0066] In step 408, the old AMF responds to the request message in step 404 by sending the UE context to the new AMF.

[0067] At this point, the old AMF will not insert the context of the MA PDU session that was successfully released from the SMF into the UE context to be sent to the new AMF.

[0068] In step 409, the remaining registration process for the UE is performed. If an MA PDU session context that is not present in the UE context received in step 408 exists in the UE, the UE can locally release the MA PDU session that exists only in the UE through the synchronization process with the new AMF.

[0069] Figure 5 An MA PDU session release method is illustrated according to an embodiment, which involves an MA PDU session release request including the specific request type of the UE when the UE is registered in a new AMF that does not support ATSSS.

[0070] In step 500, the UE can perform the registration process for the new AMF. The registration process for the new AMF can be performed according to... Figure 3 and Figure 4 The registration process for the new AMF is the same as in the embodiment.

[0071] In step 501, when the MA PDU session support indicator is not included in the registration accept message and there is a PDU session ID of the MA PDU session that received the registration accept message in the PDU session state of the registration accept message (501-1), the UE can insert the PDU session ID and request type into the PDU session release request message about all corresponding PDU session IDs, and send the PDU session release request message to the new AMF (501-2).

[0072] In this case, the release type is used to indicate the access type the UE wishes to release. When the UE wishes to release the MA PDU session only for the access type that received the registration accept message, the release type can indicate the corresponding access type. When the UE wishes to release the MA PDU session for all access types, the release type can be configured as an indicator to make a request to release all access types.

[0073] In step 502, the new AMF can send the N1 SM container received from the UE to the SMF via the Nsmf_PDUSession_UpdateSMContext request message. At this time, the new AMF also sends the SM context ID mapped to the PDU session ID.

[0074] When the release type indicates releasing all access, in step 503, the SMF completely releases the corresponding MA PDU session. Conversely, when the release type indicates only one access type, the SMF can determine, through local policies, whether to release only the access type mapped to the SM context ID for the MA PDU session or to release all access.

[0075] When the determination in step 503 is to release only one access type, in step 504, the SMF instructs the UE, the access network (AN), and the UPF to release the MA PDU session of the corresponding access type.

[0076] Simultaneously, when the determination in step 503 is made to release all access types, the SMF instructs the UE, the access network (AN), and the UPF to release the MA PDU sessions of all access types.

[0077] Figure 6 The method for releasing an MA PDU session via a UE’s MA PDU session release request is illustrated according to an embodiment when the UE registers in a new AMF that does not support ATSSS.

[0078] In step 600, the UE can perform a new AMF registration procedure. The new AMF registration procedure can be performed according to... Figure 3 and Figure 4 The registration process for the new AMF is the same as in the embodiment.

[0079] In step 601, when the MA PDU session support indicator is not included in the registration accept message and the PDU session ID of the MA PDU session exists in the PDU session state of the registration accept message of the access type that received the registration accept message (601-1), the UE inserts all the corresponding PDU session IDs into the PDU session release request message and sends the PDU session release request message to the AMF (601-2).

[0080] In step 602, the new AMF can transmit the N1 SM container received from the UE to the SMF via the Nsmf_PDUSession_UpdateSMContext request message. At this time, the new AMF also sends the SM context ID mapped to the PDU session ID.

[0081] In step 603, the SMF instructs the release of all MA PDU sessions of all access types.

[0082] Figure 7 A sequence diagram illustrating the process by which a UE releases an old MA PDU session via local release according to an embodiment is shown.

[0083] In step 700, the UE performs the registration procedure for the new AMF. When the MA PDU session support indicator is not included in the registration acceptance message and a PDU session ID for the MA PDU session exists for the access type that received the registration acceptance message, the UE can locally release all corresponding PDU session IDs.

[0084] When the MA PDU session is locally released in step 700, the UE can execute a service request procedure in step 701. At this time, the PDU session ID of the MA PDU session released in step 700 is not included in the PDU session state.

[0085] In step 702, the new AMF can transmit the N1 SM container received from the UE to the SMF via the Nsmf_PDUSession_ReleaseSMContext request message. At this time, the new AMF also sends the SM context ID mapped to the PDU session ID.

[0086] In step 703, the SMF can perform MA PDU session release for all access types.

[0087] Figure 8 The present invention illustrates a method for releasing the old MA PDU session via UpdateSMContext when the UE’s AMF is changed to an AMF that does not support ATSSS during an N2-based handover, according to an embodiment.

[0088] Reference Figure 8 In step 801, the N2 handover process can be performed. The old RAN (i.e., the source RAN or S-RAN) can send the handover-required messages and the target ID to the old AMF (i.e., the source AMF or S-AMF).

[0089] When it is determined that the old AMF can no longer support the UE, in step 802, the old AMF can perform AMF discovery / selection to select a new AMF (i.e., the target AMF or T-AMF). At this time, the old AMF can perform AMF discovery / selection through the Network Resource Library (NRF) function or through AMF local configuration.

[0090] In step 803a, when AMF discovery / selection can be performed via the NRF, the old AMF can send an Nnrf_NFDiscovery request message to the NRF. The corresponding message can include various query parameters for discovering the new AMF, and the NF type parameter can be configured as the AMF and sent.

[0091] In step 803b, the NRF can select a new AMF and send the corresponding AMF's NF profile to the old AMF. At this point, the NF profile includes supporting features for the NF services provided by the AMF (e.g., Namf_Communication). These supporting features include information about whether ATSSS is supported (i.e., MA PDU).

[0092] When the MA PDU parameter is not present in the supporting features of the message received in step 803b, in step 804, the old AMF can determine that the new AMF does not support ATSSS and proceed to step 805.

[0093] In step 805, when the old AMF determines that the new AMF does not support ATSSS, the old AMF identifies whether an MA PDU session context exists in the old AMF's UE context. If an MA PDU session context exists in the UE context, the old AMF can perform operations for the SMF to release the MA PDU session. Specifically, the old AMF can send an Nsmf_PDUSession_UpdateSMContext request message to the SMF. The Nsmf_PDUSession_UpdateSMContext request message can include information about the SM context ID, a release indication, and the access used for the MA PDU session release. Here, the SM context ID is the context identifier of the MA PDU session ID that should be released locally and is shared between the AMF and the SMF. The release indication is an indicator of the release request, and the access used for the MA PDU session release is the access type that should be released.

[0094] At this point, the old AMF can determine that the new AMF does not support ATSSS by the following methods: 1) when the support is discovered / selected via the NRF, the MA PDU support indicator is not present in the support features of the response message from the NRF in step 803b; 2) the old AMF has exchanged support features with the new AMF in the past through communication, and the MA PDU support indicator was not present in the support features at that time, and information indicating that the new AMF does not support ATSSS is stored based on this; and 3) information indicating that the new AMF does not support ATSSS is stored through the old AMF's local configuration.

[0095] When a message is received from the AMF in step 805, in step 806, the SMF determines, through its local policy, whether to release only the access type used to receive MA PDU sessions mapped to SM context IDs or to release all access. The SMF can then instruct the UPF, based on the determination result, whether to release only the access used for MA PDU sessions or to release all access.

[0096] In step 807, the SMF may send an Nsmf_PDUSession_UpdateSMContext response message, which includes the result of the request in step 805, to the old AMF.

[0097] Even if the message from the SMF includes a message requesting to be sent to the UE or AN, in step 808, the old AMF does not perform operations such as sending. The old AMF sends a Namf_Communication_CreateUEContext request message to transfer the UE context to the new AMF.

[0098] At this point, the old AMF does not insert the context of the successfully released MA PDU session into the UE context sent to the new AMF.

[0099] In step 809, the remaining procedures for the N2-based handover of the UE can be performed. When an MA PDU session context that is not present in the UE context received in step 808 exists in the UE, the UE can locally release the MA PDU session that exists only in the UE through a synchronization procedure with the new AMF.

[0100] Figure 9 This paper illustrates a method, according to an embodiment, for releasing the MA PDU session after the old AMF recognizes that the UE has been successfully registered in the new AMF when the UE requests registration in an AMF that does not support ATSSS.

[0101] Reference Figure 9In step 901, the UE may send a registration request message to the new AMF in order to perform a registration process for the new AMF (steps 1 to 3). Specifically, in step 1, the UE may send an Access Node (AN) message including the registration request message to the AN, and in step 2, the AN may determine the AMF, and in step 3, send an N2 message including the registration request message to the determined AMF (i.e., the new AMF).

[0102] In step 904, the new AMF can send a Namf_Communication_UEContextTransfer request message to the old AMF. At this time, the request message may include the access type and supported features of the UE. Supported features include information about whether the new AMF supports ATSSS, and the old AMF can use this information to identify whether the new AMF supports ATSSS.

[0103] If it is determined in step 904 that the new AMF does not support ATSSS, in step 905, the old AMF can send the UE context to the new AMF in addition to the context of the MA PDU session.

[0104] Since the AMF has been changed, in step 906, the new AMF can be registered in the Unified Data Management (UDM) via the Nudm_UECM_Registration message (including the Subscription Permanent Identifier (SUPI) and the Access Type).

[0105] In step 907, the UDM can notify the old AMF that the new AMF has been registered by sending a Nudm_UECM_DeregistrationNotification message (including SUPI and access type) to the old AMF that provides services for the corresponding UE's access type.

[0106] After receiving the message from step 907, in step 908, the old AMF can send a request to the SMF to release the MA PDU session via either the Nsmf_PDUSession_UpdateSMContext request message or the Nsmf_PDUSession_ReleaseSMContext request message. At this time, the message may include the PDU session ID and access type of the MA PDU session.

[0107] When an access type is specified in the message to the SMF, the SMF can release the corresponding access to the MA PDU in step 909. When no access type is specified, both accesses can be released.

[0108] In step 910, the remaining registration process can be performed. The UE receives a registration acceptance message from the new AMF. At this time, if the PDU session state information element (IE) of the corresponding message does not include an MA PDU session, the UE can locally release the MA PDU session only for the access that received the registration acceptance message, or locally release the MA PDU session for both access types.

[0109] Figure 10 A method is shown according to an embodiment in which, when the UE's AMF is changed to a new AMF that does not support ATSSS during an N2-based handover, the old AMF (S-AMF) receives a message from the new AMF indicating that the UE's handover was successfully performed, and then releases the MA PDU session.

[0110] Reference Figure 10 In step 1001, the S-RAN can send the message required for handover to the S-AMF.

[0111] When it is determined that the S-AMF (or the old AMF) can no longer support the UE, in step 1002, the S-AMF performs AMF discovery / selection and selects a new AMF (i.e., T-AMF). At this time, the S-AMF can perform AMF discovery / selection through the Network Resource Library (NRF) function or through AMF local configuration.

[0112] When AMF discovery / selection can be performed via NRF, in step 1003a, the S-AMF can send an Nnrf_NFDiscovery request message to the NRF. The corresponding message may include various query parameters for discovering a new AMF, and the NF type parameter can be configured as an AMF and sent.

[0113] In step 1003b, the NRF can select a new AMF and send the corresponding AMF's NF profile to the S-AMF. At this time, the NF profile includes supporting features for the NF services provided by the AMF (e.g., Namf_Communication). Supporting features include information indicating whether ATSSS is supported (i.e., MA PDU).

[0114] In step 1004, the S-AMF can determine whether the T-AMF supports ATSSS. The S-AMF determines that the T-AMF does not support ATSSS in the following cases: 1) the supporting features of the message received in step 1003b do not have an MA PDU, 2) the T-AMF knows that there is no MA PDU in the supporting features of the previous message, and 3) the T-AMF knows that it does not support ATSSS based on its local configuration.

[0115] When it is determined that T-AMF does not support ATSSS, in step 1005, S-AMF may send UE context to T-AMF in addition to MA PDU session context.

[0116] In step 1006, as part of the N2 handover process, the UE may send a handover confirmation message to the T-RAN, and the T-RAN may send a handover notification message to the T-AMF.

[0117] In step 1007, the T-AMF can send a message to the S-AMF indicating that the N2 handover of the UE has been successfully performed.

[0118] After receiving the message from step 1007, in step 1008, the S-AMF can send a request to the SMF to release the MA PDU session via either the Nsmf_PDUSession_UpdateSMContext request message or the Nsmf_PDUSession_ReleaseSMContext request message. At this time, the message may include the PDU session ID and access type of the MA PDU session.

[0119] In step 1009, when an access type is specified in the message to the SMF, the SMF can release the corresponding access for the MA PDU. When no access type is specified, both access types are released.

[0120] In step 1010, the remaining handover process can be performed. The UE receives a registration acceptance message from the new AMF. At this time, if there is an MA PDU session that is not included in the PDU session state IE of the corresponding message, the UE can locally release the MA PDU session only for the access that received the registration acceptance message, or locally release the MA PDU session for both access types.

[0121] Figure 11 A block diagram of the structure of a UE according to an embodiment is shown.

[0122] Reference Figure 11 The UE may include a transceiver 1110, a UE controller 1120, and a storage unit 1130. In this disclosure, the UE controller 1220 may be defined as a circuit, an application-specific integrated circuit, or at least one processor.

[0123] Transceiver 1110 can send signals to and receive signals from another network entity. Transceiver 1110 can, for example, receive system information from a base station and receive synchronization signals or reference signals.

[0124] The UE controller 1120 can control the overall operation of the UE according to the embodiments presented in this disclosure. For example, the UE controller 1120 can control the signal flow between blocks to perform UE operations according to the flowchart above.

[0125] Storage unit 1130 can store at least one piece of information sent and received by transceiver 1110 and information generated by UE controller 1120.

[0126] Figure 12 A block diagram of the structure of higher nodes according to an embodiment is shown.

[0127] Figure 12 The block diagram shown can be a block diagram of the higher nodes mentioned above (such as AMF, SMF, and UPF).

[0128] In this disclosure, core network entities or network functions such as AMF, SMP, and UPF are referred to as higher nodes.

[0129] Reference Figure 12 The higher node may include a transceiver 1210, a higher node controller 1220, and a storage unit 1230. In this invention, the higher node controller 1220 may be defined as a circuit, an application-specific integrated circuit, or at least one processor.

[0130] Transceiver 1210 can send signals to and receive signals from another network entity. According to embodiments, transceiver 1210 can send signals to, for example, a neighboring higher-level node and receive signals from, for example, a neighboring higher-level node.

[0131] According to the embodiments presented in this disclosure, the higher node controller 1220 can control the overall operation of the higher node. For example, the higher node controller 1220 can control the signal flow between blocks to execute the operation of the higher node according to the flowchart above.

[0132] Storage unit 1230 can store at least one piece of information sent and received by transceiver 1210 and information generated by higher node controller 1220.

[0133] According to an embodiment, when a UE registered in an AMF that supports ATSSS registers in an AMF that does not support ATSSS, the old MA PDU session can be effectively released to perform smooth communication.

[0134] The methods disclosed in the claims and / or the methods according to the various embodiments described in this disclosure may be implemented in hardware, software, or a combination of hardware and software.

[0135] When the method is implemented in software, a computer-readable storage medium may be provided for storing one or more programs (software modules). The one or more programs stored in the computer-readable storage medium may be configured to be executed by one or more processors within an electronic device. The at least one program may include instructions that cause the electronic device to perform the method as defined in the appended claims and / or as disclosed herein, according to various embodiments of this disclosure.

[0136] The program (software module or software) can be stored in non-volatile memory, including random access memory and flash memory, read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), disk storage devices, optical disc ROM (CD-ROM), digital versatile disc (DVD), or other types of optical storage devices, or magnetic tape cassettes. Alternatively, any combination of some or all of these can form the memory in which the program is stored. Furthermore, multiple such memories can be included in an electronic device.

[0137] Furthermore, the program can be stored in a connectable storage device that can be accessed by the electronic device via a communication network such as the Internet, intranet, local area network (LAN), wide area network (WLAN), and storage area network (SAN), or a combination thereof. Such a storage device can be connected to a device executing embodiments of this disclosure via an external port. Additionally, a separate storage device on the communication network can be connected to a device executing embodiments of this disclosure.

[0138] In the detailed embodiments described above, elements included in this disclosure are represented in a singular or plural form according to the presented embodiments. However, for ease of description, singular or plural forms have been suitably chosen as presented, and this disclosure is not limited to elements represented in a singular or plural form. Thus, an element represented in a plural form may also include a single element, or an element represented in a singular form may include multiple elements.

[0139] Although this disclosure has been described with reference to various embodiments, those skilled in the art may suggest various changes and modifications. This disclosure is intended to cover such changes and modifications that fall within the scope of the appended claims.

Claims

1. A method performed by a first Access and Mobility Management Function (AMF) entity in a wireless communication system, the method comprising: Receive a first message, the first message including information related to the support characteristics of the second AMF entity; Based on the information, identify whether the second AMF entity supports access service control, switching, and ATSSS functions. If the second AMF entity does not support the ATSSS function, a second message including the user equipment (UE) context is sent to the second AMF entity, wherein the context for the multiple access packet data unit (MA PDU) session is not included in the UE context; and A third message is sent to the Session Management Function (SMF) entity requesting the release of the MA PDU session. The MA PDU session is released based on the third message.

2. The method according to claim 1, in, The first message was received from the second AMF entity, and The first message is a message used to request the transfer of the UE context stored in the first AMF entity to the second AMF entity.

3. The method according to claim 1, in, The first message is provided by the Network Resource Repository (NRF) entity. Wherein, the first AMF entity is the source AMF entity associated with the handover. Wherein, the second AMF entity is the target AMF entity associated with the handover, and The first message includes the Network Function (NF) profile of the second AMF entity, and the NF profile includes the information.

4. The method of claim 3, further comprising receiving a fourth message from the second AMF entity notifying of a successful handover. in, The third message is sent after the fourth message is received.

5. A first Access and Mobility Management Function (AMF) entity in a wireless communication system, the first AMF entity comprising: A transceiver is configured to send and receive signals; as well as The controller, connected to the transceiver and configured to: Receive a first message, the first message including information related to the supporting characteristics of the second AMF entity. Based on the information, identify whether the second AMF entity supports access service control, handover, and ATSSS functions. If the second AMF entity does not support the ATSSS function, a second message including the user equipment (UE) context is sent to the second AMF entity, wherein the context for the multiple access packet data unit (MA PDU) session is not included in the UE context. A third message is sent to the Session Management Function (SMF) entity requesting the release of the MA PDU session. The MA PDU session is released based on the third message.

6. The first AMF entity according to claim 5, in, The first message was received from the second AMF entity, and The first message is a message used to request the transfer of the UE context stored in the first AMF entity to the second AMF entity.

7. The first AMF entity according to claim 5, in, The first message is provided by the Network Resource Repository (NRF) entity. Wherein, the first AMF entity is the source AMF entity associated with the handover. Wherein, the second AMF entity is the target AMF entity associated with the handover, and The first message includes the Network Function (NF) profile of the second AMF entity, and the NF profile includes the information.

8. The first AMF entity according to claim 7, in, The controller is also configured to receive a fourth message from the second AMF entity notifying of a successful handover. The third message is sent after the fourth message is received.

9. A method performed by a Session Management Function (SMF) entity in a wireless communication system, the method comprising: Based on information related to the support characteristics of the second AMF entity, a first message requesting the release of a Multiple Access Packet Data Unit (MA PDU) session is received from the first Access and Mobility Management Function (AMF) entity. as well as Release the MA PDU session based on the first message. The information indicates whether the second AMF entity supports access service control, handover, and ATSSS functions, and Where, if the second AMF entity does not support the ATSSS function based on the information, a second message including the user equipment (UE) context is passed to the second AMF entity, and the context for the MA PDU session is not included in the UE context.

10. The method according to claim 9, in, The first message is received after the first AMF receives a third message requesting the transfer of the UE context stored in the first AMF entity to the second AMF entity, the third message including the information, and The second message is transmitted in response to the third message.

11. The method according to claim 9, in, The information is provided by the Network Resource Library (NRF) entity, wherein the first AMF entity is the source AMF entity associated with the handover. The second AMF entity is the target AMF entity associated with the handover. The information is included in the Network Function (NF) profile of the second AMF entity, and The first message is received after the first AMF entity receives the third message notifying the successful handover.

12. A Session Management Function (SMF) entity in a wireless communication system, the SMF entity comprising: A transceiver is configured to send and receive signals; as well as The controller, connected to the transceiver and configured to: Based on information related to the support characteristics of the second AMF entity, a first message requesting the release of a Multiple Access Packet Data Unit (MA PDU) session is received from the first Access and Mobility Management Function (AMF) entity. as well as Release the MA PDU session based on the first message. The information indicates whether the second AMF entity supports access service control, switching, and ATSSS functions, and Where, if the second AMF entity does not support the ATSSS function based on the information, a second message including the user equipment (UE) context is passed to the second AMF entity, and the context for the MA PDU session is not included in the UE context.

13. The SMF entity according to claim 12, in, The first message is received after the first AMF receives a third message requesting the transfer of the UE context stored in the first AMF entity to the second AMF entity, the third message including the information, and The second message is transmitted in response to the third message.

14. The SMF entity according to claim 12, in, The information is provided by the Network Resource Repository (NRF) entity. Wherein, the first AMF entity is the source AMF entity associated with the handover, and Wherein, the second AMF entity is the target AMF entity associated with the handover, and The information is included in the Network Function (NF) profile of the second AMF entity.

15. The SMF entity according to claim 14, in, The first message is received after the first AMF entity receives the third message notifying of a successful handover.

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