Method and device for selecting AMF when requesting synchronization for multiple ues considering coverage in wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a higher data transmission rate A method of a time sensitive communication time synchronization function (TSCTSF) according to an embodiment of the present disclosure may comprise the steps of: receiving a message related to synchronization from an application function (AF); discovering at least one access and mobility management function (AMF) through a network entity; transmitting, to the at least one AMF, a first message including information on user equipments (UEs); and receiving, from the at least one AMF, a second message including information on an area of interest (AOI) on the basis of the information on the UEs.

Description

Method and device for selecting AMF when requesting synchronization for multiple UEs considering coverage in a wireless communication system

[0001] The present invention relates to a wireless communication system, and more particularly, to a method for providing time synchronization between wireless terminals in a wireless communication system using a 3GPP 5GS (5G System). In particular, the present invention relates to a method for providing time synchronization between wireless terminals to multiple terminals using coverage conditions.

[0002] 5G mobile communication technology defines a wide frequency band to enable fast transmission speeds and new services, and can be implemented not only in the sub-6GHz frequency band such as 3.5 gigahertz (3.5GHz), but also in the ultra-high frequency band called millimeter wave (mmWave) such as 28GHz and 39GHz ('Above 6GHz'). In addition, for 6G mobile communication technology, which is called the system after 5G communication (Beyond 5G), implementation in the terahertz band (for example, the 3 terahertz (3THz) band at 95GHz) is being considered to achieve a transmission speed that is 50 times faster than 5G mobile communication technology and an ultra-low latency time that is reduced to one-tenth.

[0003] In the early stages of 5G mobile communication technology, the goal is to support services and satisfy performance requirements for enhanced Mobile Broadband (eMBB), Ultra-Reliable Low-Latency Communications (URLLC), and massive Machine-Type Communications (mMTC). These include beamforming and massive MIMO to mitigate path loss of radio waves in ultra-high frequency bands and increase the transmission distance of radio waves, support for various numerologies (such as operation of multiple subcarrier intervals) and dynamic operation of slot formats for efficient use of ultra-high frequency resources, initial access technology to support multi-beam transmission and wideband, definition and operation of BWP (Bidth Part), new channel coding methods such as LDPC (Low Density Parity Check) codes for large-capacity data transmission and Polar Code for reliable transmission of control information, and L2 pre-processing (L2). Standardization has been made for network slicing, which provides dedicated networks specialized for specific services, and pre-processing.

[0004] Currently, discussions are underway to improve and enhance the initial 5G mobile communication technology in consideration of the services that 5G mobile communication technology was intended to support, and physical layer standardization is in progress for technologies such as V2X (Vehicle-to-Everything) to help autonomous vehicles make driving decisions and increase user convenience based on their own location and status information transmitted by vehicles, NR-U (New Radio Unlicensed) for the purpose of system operation that complies with various regulatory requirements in unlicensed bands, NR terminal low power consumption technology (UE Power Saving), Non-Terrestrial Network (NTN), which is direct terminal-satellite communication to secure coverage in areas where communication with terrestrial networks is impossible, and Positioning.

[0005] In addition, standardization of wireless interface architecture / protocols is in progress for technologies such as intelligent factories (Industrial Internet of Things, IIoT) to support new services through linkage and convergence with other industries, Integrated Access and Backhaul (IAB) that provides nodes for expanding network service areas by integrating wireless backhaul links and access links, Mobility Enhancement technology including Conditional Handover and Dual Active Protocol Stack (DAPS) handover, and 2-step random access (2-step RACH for NR) that simplifies random access procedures. Standardization is also in progress for system architecture / services such as 5G baseline architecture (e.g., Service-based Architecture, Service-based Interface) for grafting Network Functions Virtualization (NFV) and Software-Defined Networking (SDN) technologies, and Mobile Edge Computing (MEC) that provides services based on the location of the terminal.

[0006] Once these 5G mobile communication systems are commercialized, an explosive increase in connected devices will be connected to the communication network, necessitating enhanced functionality and performance of 5G mobile communication systems and integrated operation of these connected devices. To this end, new research will be conducted on improving 5G performance and reducing complexity, supporting AI services, supporting metaverse services, and drone communications by utilizing eXtended Reality (XR), Artificial Intelligence (AI), and Machine Learning (ML) to efficiently support Augmented Reality (AR), Virtual Reality (VR), and Mixed Reality (MR).

[0007] In addition, the development of these 5G mobile communication systems includes new waveforms to ensure coverage in the terahertz band of 6G mobile communication technology, multi-antenna transmission technologies such as Full Dimensional MIMO (FD-MIMO), Array Antenna, and Large Scale Antenna, metamaterial-based lenses and antennas to improve the coverage of terahertz band signals, high-dimensional spatial multiplexing technology using Orbital Angular Momentum (OAM), Reconfigurable Intelligent Surface (RIS) technology, as well as full duplex technology to improve the frequency efficiency and system network of 6G mobile communication technology, satellite, AI (Artificial Intelligence) from the design stage and AI-based communication technology that realizes system optimization by internalizing end-to-end AI support functions, and ultra-high-performance communication and computing resources to provide services with complexity that exceeds the limits of terminal computing capabilities. It can serve as a basis for the development of next-generation distributed computing technologies that can be realized by utilizing them.

[0008] When a 3GPP network (5GS) becomes a synchronization source and provides time synchronization services to terminals, or when providing coverage conditions, it is necessary to confirm the terminal's location, so the terminal's location information can be confirmed with the AMF. At this time, if there are multiple terminals eligible for the synchronization service, each terminal requests the AMF registered by the terminal to confirm its location information. Later, when the terminal performs a handover to change AMFs, the location information sharing requested from the previous AMF must be released, and the terminal's location information must be requested from the changed AMF. In other words, as the number of terminals eligible for the synchronization service increases and the mobility of the terminals increases, the signaling due to this AMF change increases, which can act as a burden on the network.

[0009] The present invention for solving the above problems is characterized by a method for Time Sensitive Communication Time Synchronization Function (TSCTSF) in a wireless communication system, comprising: a step of receiving a message related to synchronization from an Application Function (AF); a step of discovering at least one Access and Mobility Management Function (AMF) through a network entity; a step of transmitting a first message including information on UEs (User equipments) to the at least one AMF; and a step of receiving a second message including information on an Area of ​​interest (AOI) based on the information on the UEs from the at least one AMF.

[0010] In one embodiment, the information about the UEs is characterized by including at least one of a UE identifier (ID) list, a group ID, or a Data Network Name (DNN) / S-NSSAI (Single Network Slice Selection Assistance Information).

[0011] In one embodiment, the method further comprises a step of discovering at least one AMF based on a coverage condition included in a message related to synchronization through the network entity.

[0012] In one embodiment, the information about the UEs is characterized by including information about all AMFs.

[0013] In addition, in another embodiment of the present invention, a method performed by an AMF (Access and Mobility Management Function) in a wireless communication system comprises the steps of: receiving a first message including information on UEs (User equipments) from a TSCTSF (Time Sensitive Communication Time Synchronization Function); checking whether a condition included in the information on the UEs is satisfied; and transmitting a second message including information on an AOI (Area of ​​interest) based on the information on the UEs to the TSCTSF, wherein the AMF is discovered through a network entity, and a message related to synchronization is transmitted from an AF (Application Function) to the TSCTSF.

[0014] In addition, in another embodiment of the present invention, in a wireless communication system, a Time Sensitive Communication Time Synchronization Function (TSCTSF) includes a transceiver capable of transmitting and receiving at least one signal; and a control unit coupled to the transceiver, wherein the control unit is configured to: receive a message related to synchronization from an Application Function (AF), discover at least one Access and Mobility Management Function (AMF) through a network entity, transmit a first message including information on User Equipments (UEs) to the at least one AMF, and receive a second message including information on an Area of ​​Interest (AOI) based on the information on the UEs from the at least one AMF.

[0015] In addition, in another embodiment of the present invention, in a wireless communication system, in an AMF (Access and Mobility Management Function), a transceiver capable of transmitting and receiving at least one signal; and a control unit coupled to the transceiver, wherein the control unit is configured to: receive a first message including information on UEs (User equipments) from a TSCTSF (Time Sensitive Communication Time Synchronization Function), determine whether a condition included in the information on the UEs is satisfied, and transmit a second message including information on an AOI (Area of ​​interest) based on the information on the UEs to the TSCTSF, wherein the AMF is discovered through a network entity, and a message related to synchronization is transmitted from an AF (Application Function) to the TSCTSF.

[0016] According to one embodiment of the present invention, when 5GS becomes a Sync (Synchronization) Source and provides Sync service to UE and also provides coverage conditions, when targeting multiple terminals, the burden on the network can be prevented by eliminating additional signaling that occurs each time a terminal performs handover between AMFs.

[0017] Figure 1 is a diagram for explaining a case where coverage conditions are added when providing 5GS Sync through a 3GPP network.

[0018] Figure 2a is a diagram showing the Area of ​​Interest subscription for each UE in the Sync service target UE list.

[0019] Figure 2b is a diagram showing the operation when an AMF handover occurs among the Area of ​​Interest subscriptions for each UE in the Sync service target UE list.

[0020] Figure 3a is a diagram showing the Area of ​​Interest subscription for each UE in the Sync service target group.

[0021] Figure 3b is a diagram showing the operation when an AMF handover occurs among the Area of ​​Interest subscriptions for each UE of the Sync service target group.

[0022] Figure 4a is a diagram showing an Area of ​​Interest subscription for a UE of a Sync service target DNN / -S-NSSAI.

[0023] Figure 4b is a diagram showing an Area of ​​Interest subscription for a UE of a Sync service target DNN / -S-NSSAI.

[0024] Figure 4c is a diagram showing the operation when an AMF-to-AMF handover occurs during an Area of ​​Interest subscription for a UE of a Sync service target DNN / -S-NSSAI.

[0025] Figure 5a is a diagram showing the operation when All-AMF Indication is applied to the Area of ​​Interest subscription for each UE in the Sync service target UE list.

[0026] Figure 5b is a diagram showing the operation when All-AMF Indication is applied to the Area of ​​Interest subscription for each UE in the Sync service target UE list.

[0027] Figure 5c is a diagram showing the operation when an inter-AMF handover occurs when the Area of ​​Interest subscription for each UE in the Sync service target UE list is applied with All-AMF Indication.

[0028] Figure 6a is a diagram showing the operation when All-AMF Indication is applied to the Area of ​​Interest subscription for each UE of the Sync service target group.

[0029] Figure 6b is a diagram showing the operation when All-AMF Indication is applied to the Area of ​​Interest subscription for each UE of the Sync service target group.

[0030] Figure 6c is a diagram showing the operation when an inter-AMF handover occurs when the Area of ​​Interest subscription for each UE of the Sync service target group is applied with the All-AMF Indication.

[0031] Figure 7a is a diagram showing the operation when All-AMF Indication is applied to the Area of ​​Interest subscription for each UE of the Sync service target DNN / S-NSSAI.

[0032] Figure 7b is a diagram showing the operation when All-AMF Indication is applied to the Area of ​​Interest subscription for each UE of the Sync service target DNN / S-NSSAI.

[0033] Figure 7c is a diagram showing the operation when an inter-AMF handover occurs when the Area of ​​Interest subscription for each UE of the Sync service target DNN / S-NSSAI is applied with the All-AMF Indication.

[0034] Figure 8 is a diagram illustrating the structure of a terminal according to one embodiment of the present invention.

[0035] FIG. 9 is a diagram illustrating the structure of a network entity according to one embodiment of the present invention.

[0036] The operating principles of the present invention will be described in detail below with reference to the attached drawings. In the following description of the present invention, detailed descriptions of known functions or components will be omitted if they are deemed to unnecessarily obscure the gist of the invention. Furthermore, the terms described below are defined based on their functions in the present invention and may vary depending on the intentions or practices of the user or operator. Therefore, their definitions should be based on the overall content of this specification.

[0037] The terms used in the following description to identify connection nodes, terms referring to network entities, terms referring to messages, terms referring to interfaces between network entities, and terms referring to various identification information are provided for convenience of explanation. Therefore, the present invention is not limited to the terms described below, and other terms referring to objects with equivalent technical meanings may be used.

[0038] For convenience of explanation, the present invention uses terms and names defined in the 5GS and NR standards, which are the most recent standards defined by the 3rd Generation Partnership Project (3GPP) among the existing communication standards. However, the present invention is not limited to the above terms and names and can be equally applied to wireless communication networks that follow other standards. In particular, the present invention can be applied to the 3GPP 5GS / NR (5th generation mobile communication standard).

[0039] When used for applications such as smart grids, accurate time synchronization between terminals is required. Sync services can only be provided in certain areas. Outside of these areas, services may not be available, or a different type of sync service may need to be applied. Accurate time synchronization between terminals is also required for factory automation. Audio / video sharing applications also require accurate time synchronization between terminals. Financial applications also require this. For example, stock trading terminals must perform buys and sells based on accurate time synchronization.

[0040]

[0041] Figure 1 is a diagram for explaining a case where coverage conditions are added when providing 5GS Sync through a 3GPP network.

[0042] 5GS (5G System) can provide synchronization service to terminals at the request of AF (Application Function). 5GS can link with external AF through TSCTSF (Time Sensitive Communications and Time Synchronization Function) / NEF (network exposure function). In this case, TSCTSF / NEF can exchange management information with NW-TT (Network Side TSN Translator) and DS-TT (Device Side TSN Translator). NW-TT can periodically generate sync messages to match synchronization and transmit time information included in the sync messages to DS-TT. In addition, TSCTSF / NEF can link with SMF (Session Management Function), AMF (Access and Mobility Management Function), PCF (Policy Control Function), UDM / UDR, etc. to transmit 5GS information to external AF or apply external AF requests to the 5GS System. In particular, TSCTSF / NEF stores necessary information in the UDR (user data repository) and, through the notification process, can deliver updated information to the UDM (Unified Data Management) / UDR or PCF via notification. This method can be called the (g)PTP-based Sync method.

[0043] It is also possible to support time synchronization between terminals by adjusting RRC (Radio Resource Control) or SIB (System Information Block) by transmitting it to the RAN (Radio Access Network) of 5G that applies the AF request. This method can be called AS (Access Stratum)-based Sync method. The RRC (Radio Resource Control) / SIB (System Information Block) transmission frequency for transmitting time information can be increased to a level that satisfies the accuracy. The base station can adjust the time synchronization accuracy by measuring the precise delay time by adjusting the cycle of exchanging messages for measuring the delay time between a specific terminal and the base station through RRC. In addition, the base station can adjust the time synchronization accuracy by adjusting the cycle of including time information in the information broadcast to all terminals through SIB.

[0044] AF's Sync request can be either (g)PTP-based or AS-based, but AF cannot know the internal status information of 5GS, such as the supportable Sync Accuracy, the number of corresponding UEs, and whether the corresponding UEs are Idle / Active. Therefore, even if AF makes a (G)PTP-based request, it may have to be processed as AS-based 5GS Sync. Even if AF makes an AS-based request, it may have to be processed as (G)PTP-based 5GS Sync. Or, even if AF makes an NAS- or AS-based request, both AS-based 5GS Sync and (G)PTP-based 5GS Sync may have to be processed.

[0045] 5GS Sync provisioning can also be provided based on subscription data in UDM. In addition to conditions such as each UE's sync service subscription and Sync Error Budget, coverage conditions may also be included.

[0046] The method for specifying the target UE for the sync service can be as follows: a single UE (A UE), a list of multiple UEs (A list of UEs), a group of UEs identified by Internal Group ID, UEs with DNN / S-NSSAI (Any UEs with DNN / S-NSSAI), etc.

[0047]

[0048] Figure 2a is a diagram showing the Area of ​​Interest subscription for each UE in the Sync service target UE list.

[0049] Referring to Figure 2a, when a Sync service has a coverage condition and its target is a UE List, 5GS can request an Area of ​​Interest for each UE from AMF.

[0050] At step 200, UE1 (231) can connect to gNB1 (241) and register with AMF1 (261). At this time, UE Capability, Cell ID / RAN ID / TA ID / SA ID, etc. may be included. AMF1 (261), which receives the Registration Request from UE1 (231), can verify subscriber information through UDM and store the related Subscription Context in AMF. In addition, AMF sends the related Context to gNB1 (241), sends the remaining Registration Response to UE1 (231), and completes the remaining Registration process.

[0051] At step 200a, UE2 (232) can connect to gNB2 (242) and register with AMF2 (262). At this time, UE Capability, Cell ID / RAN ID / TA ID / SA ID, etc. may be included. AMF2 (262), which receives the Registration Request from UE2 (232), can verify subscriber information through UDM and store the related Subscription Context in AMF. In addition, AMF sends the related Context to gNB2 (242), sends the remaining Registration Response to UE2 (232), and completes the remaining Registration process.

[0052] In step 201, the AF (290) can send a 5GS Sync Request for target UEs to the TSCTSF (Time Sensitive Communications and Time Synchronization Function) / NEF (Network Exposure Function) (285). The 5GS Sync Request can include the required Synchronization Accuracy as a Sync Error Budget. In addition, it can specify the Coverage to which the Sync Service should be applied. The indication of the target UE can be expressed as a UE ID list, a Group ID, or a DNN (Data Network Name) / S-NSSAI (Single Network Slice Selection Assistance Information). In addition, an RA Adjust Request can also be included. At this time, the TSCTSF / NEF can derive TA IDs corresponding to the coverage conditions and manage them as a TA List. In the above embodiment, the target of the Sync service is provided as a UE List.

[0053] In step 202, TSCTSF / NEF (285) can learn the AMF in which each target UE is registered in the UDM. At this stage, NRF can be used to learn the location information of the AMF. For example, TSCTSF can learn that UE1 is located in AMF1 and UE2 is located in AMF2. At this stage, TSCTSF can also request notification if the AMFs where the UEs are located have changed. Afterwards, TSCTSF can request the Area of ​​Interest for each UE from each AMF.

[0054] In step 203, TSCTSF (285) may request AMF1 (261) to notify UE1 (231) of its location and whether it belongs to an AoI (Area of ​​Interest). At this time, the UE's location may be converted and used using a list of TA IDs known to 3GPP.

[0055] At step 204, AMF1 (261) can notify TSCTSF / NEF (285) whether the current location of UE1 (231) meets the coverage conditions and that it is subscribed.

[0056] In step 205, TSCTSF / NEF (285) can report the current status of the Sync Request to AF (290). At this time, UE1, Sync Error Budget, Coverage Condition, etc. can be included.

[0057] In step 206, AF (290) can use the report of step 205 to re-check whether the Sync Error Budget or Coverage conditions are satisfied, and if necessary, send a modified Sync service request to TSCTSF / NEF (285).

[0058] In step 207, AF (290) may send a modified Sync service request to TSCTSF / NEF (285). At this time, UE1, Sync Error Budget, and Coverage Condition may be included.

[0059] At step 208, TSCTSF (285) can check again whether the coverage condition is satisfied.

[0060] In step 209, TSCTSF (285) can check again whether the requested Sync Error Budget can be satisfied through the RAN's Sync Error Budget transmitted through AMF1 (261).

[0061] In step 210, TSCTSF / NEF (285) may notify AF (290) of the current status of the Sync Request. At this time, UE1, Sync Error Budget, Location, Range, etc. may be included.

[0062] In step 211, TSCTSF (285) can apply a Sync service to UE1. At this time, the request of TSCTSF can be delivered to AMF via PCF. AMF can apply this request to gNB1 to which UE1 belongs and only apply Sync service using RAN technology such as SIB broadcast and RRC signaling between gNB1 and UE1. Alternatively, TSCTSF can additionally apply a (g)PTP-based Sync service that periodically delivers Sync messages from NW-TT of UPF1 to DS-TT of UE1 at the same time as the Sync service using RAN technology by sending signals to NW-TT and DS-TT. This process is as described in Fig. 1.

[0063] In step 203a, TSCTSF (285) may request AMF2 (262) to notify UE2 (232) of its location and whether it belongs to an AoI. At this time, the UE's location may be converted and used using a TA ID list known to 3GPP.

[0064] At step 204a, AMF2 (262) can notify TSCTSF / NEF (285) whether UE2's current location and location meet the coverage conditions and that it is subscribed.

[0065] In step 205a, TSCTSF / NEF (285) can report the current status of the Sync Request to AF (290). At this time, UE2, Sync Error Budget, Coverage Condition, etc. can be included.

[0066] In step 206a, AF (290) can use the report of step 205a to re-check whether the Sync Error Budget or Coverage conditions are satisfied, and if necessary, send a modified Sync service request to TSCTSF / NEF (285).

[0067] At step 207a, AF (290) may send a modified Sync service request to TSCTSF / NEF (285). At this time, UE2, Sync Error Budget, and Coverage Condition may be included.

[0068] At step 208a, TSCTSF (285) can check again whether the coverage condition is satisfied.

[0069] In step 209a, TSCTSF (285) can check again whether the requested Sync Error Budget can be satisfied through the RAN's Sync Error Budget transmitted through AMF2 (262).

[0070] In step 210a, TSCTSF / NEF (285) may notify AF (290) of the current status of the Sync Request. At this time, UE2, Sync Error Budget, Location, Range, etc. may be included.

[0071] In step 211a, TSCTSF (285) can apply a Sync service to UE2. At this time, the request of TSCTSF can be delivered to AMF2 via PCF. AMF2 can apply this request to gNB2 to which UE2 belongs, and can only apply a Sync service using RAN technology such as SIB broadcast and RRC signaling between gNB2 and UE2. Alternatively, TSCTSF can additionally apply a (g)PTP-based Sync service that sends signals to NW-TT and DS-TT, and periodically delivers Sync messages from NW-TT of UPF2 to DS-TT of UE2 simultaneously with the Sync service using RAN technology. This process is as described in Fig. 1.

[0072]

[0073] Figure 2b is a diagram showing the operation when an AMF handover occurs among the Area of ​​Interest subscriptions for each UE in the Sync service target UE list.

[0074] Referring to Figure 2b, when a UE moves beyond the AMF area, Subscription / De-Subscription signaling for the Area of ​​Interest subscription may also occur simultaneously. In this case, as the number of target UEs increases or the mobility of the UEs increases, both the signaling load and the signaling load may increase, which may become problematic.

[0075] In step 212, UE1 (231) moves from gNB1 (241) to gNB3 (243) and moves from the area of ​​AMF1 (261) to the area of ​​AMF3 (263) to perform registration in AMF3.

[0076] In step 213, UE context information can be transferred between AMF1 (261) and AMF3 (263) according to the handover of UE1.

[0077] In step 214, UDM / UDR (280) can notify TSCTSF (285) that an update has occurred due to a change in AMF of UE1. That is, UDM / UDR (280) can notify TSCTSF (285) that the location where UE1 (231) is registered has changed from AMF1 (261) to AMF3 (263).

[0078] In step 215, AMF1 (261) can notify TSCTSF (285) of a change in location of UE1. At this time, UE1, Coverage (list of TAs) can be included.

[0079] In step 216, TSCTSF (285) can release UE1's location notification subscription to AMF1 (261). At this time, the De-Subscription request can include UE1, Location, and Coverage.

[0080] In step 217, TSCTSF (285) may request a location notification subscription for UE1 from AMF3 (263). At this time, the subscription request may include UE1, Location, and Coverage.

[0081] At step 218, AMF3 (263) can notify TSCTSF / NEF (285) whether UE1's current location and location meet the coverage conditions and that it is subscribed.

[0082] In step 219, TSCTSF / NEF (285) can report the current status of the Sync Request to AF (290). At this time, UE1, Sync Error Budget, Coverage Condition, etc. can be included.

[0083] In step 220, AF (290) can use the report of step 219 to recheck whether the Sync Error Budget or Coverage conditions are satisfied, and if necessary, send a modified Sync service request to TSCTSF / NEF (285).

[0084] At step 221, AF (290) may send a modified Sync service request to TSCTSF / NEF (285). At this time, UE1, Sync Error Budget, and Coverage Condition may be included.

[0085] At step 222, TSCTSF (285) can check again whether the coverage condition is satisfied.

[0086] In step 223, TSCTSF (285) can check again whether the requested Sync Error Budget can be satisfied through the RAN's Sync Error Budget transmitted through AMF1 (261).

[0087] In step 224, TSCTSF / NEF (285) may notify AF (290) of the current status of the Sync Request. At this time, UE1, Sync Error Budget, Location, Range, etc. may be included.

[0088] In step 225, TSCTSF (285) can apply a Sync service to UE1. At this time, the request of TSCTSF can be delivered to AMF via PCF. AMF can apply this request to gNB1 to which UE1 belongs and only apply Sync service using RAN technology such as SIB broadcast and RRC signaling between gNB1 and UE1. Alternatively, TSCTSF can additionally apply a (g)PTP-based Sync service that periodically delivers Sync messages from NW-TT of UPF1 to DS-TT of UE1 at the same time as the Sync service using RAN technology by sending signals to NW-TT and DS-TT. This process is as described in Fig. 1.

[0089]

[0090] Figure 3a is a diagram showing the Area of ​​Interest subscription for each UE in the Sync service target group.

[0091] Referring to Figure 3a, when a Sync service has a coverage condition and its target is a UE List with an Internal Group Identifier, 5GS can request an Area of ​​Interest for each UE from AMF.

[0092] At step 300, UE1 (331) can connect to gNB1 (341) and register with AMF1 (361). At this time, UE Capability, Cell ID / RAN ID / TA ID / SA ID, etc. may be included. AMF1 (361), which receives the Registration Request from UE1 (331), can verify subscriber information through UDM and store the related Subscription Context in AMF. In addition, AMF sends the related Context to gNB1 (341) and sends the remaining Registration Response to UE1 (331), completing the remaining Registration process.

[0093] At step 300a, UE2 (332) can connect to gNB2 (342) and register with AMF2 (362). At this time, UE Capability, Cell ID / RAN ID / TA ID / SA ID, etc. may be included. AMF2 (362), which receives the Registration Request from UE2 (332), can verify subscriber information through UDM and store the related Subscription Context in AMF. In addition, AMF sends the related Context to gNB2 (342), sends the remaining Registration Response to UE2 (332), and completes the remaining Registration process.

[0094] In step 301, the AF (290) can send a 5GS Sync Request for target UEs to the TSCTSF (Time Sensitive Communications and Time Synchronization Function) / NEF (Network Exposure Function) (285). This Request can include the required Synchronization Accuracy as a Sync Error Budget. In addition, it can specify the Coverage to which the Sync Service should be applied. The indication of the target UE can be expressed as a UE ID list, a Group ID, or a DNN (Data Network Name) / S-NSSAI (Single Network Slice Selection Assistance Information). In addition, an RA Adjust Request can also be included. At this time, the TSCTSF / NEF can derive TA IDs that meet the coverage conditions and manage them as a TA List. In this example, the target of the Sync service is provided as a Group ID. The Group ID provided by AF is an External Group ID that can be used outside of 5GS, and NEF or TSCTSF can be converted to an Internal Group ID or converted to an Internal Group ID in UDM.

[0095] In step 302, the TSCTSF / NEF (385) can identify the AMF in which each UE of a group, identified by a Group ID in the UDM, is registered. At this step, the NRF can also be used to identify the location information of the AMF. For example, the TSCTSF (385) can identify that UE1 is located in AMF1 and UE2 is located in AMF2. At this step, the TSCTSF (385) can also request notification if the AMFs where the UEs are located have changed. Thereafter, the TSCTSF (385) can request the Area of ​​Interest for each UE from each AMF.

[0096] In step 303, TSCTSF (385) may request AMF1 (361) to report information about UE1's location and whether it belongs to an AoI. At this time, the UE's location may be converted and used using a list of TA IDs known to 3GPP.

[0097] At step 304, AMF1 (361) can notify TSCTSF / NEF (385) whether UE1's current location and location meet the coverage conditions and that it is subscribed.

[0098] In step 305, TSCTSF / NEF (385) can report the current status of the Sync Request to AF (390). At this time, UE1, Sync Error Budget, Coverage Condition, etc. can be included.

[0099] In step 306, AF (390) can use the report of step 305 to re-check whether the Sync Error Budget or Coverage conditions are satisfied, and if necessary, send a modified Sync service request to TSCTSF / NEF (385).

[0100] In step 307, AF (390) may send a modified Sync service request to TSCTSF / NEF (385). At this time, UE1, Sync Error Budget, and Coverage Condition may be included.

[0101] At step 308, TSCTSF (385) can check again whether the coverage condition is satisfied.

[0102] In step 309, TSCTSF (385) can check again whether the requested Sync Error Budget can be satisfied through the RAN's Sync Error Budget transmitted through AMF1 (361).

[0103] In step 310, TSCTSF / NEF (385) may notify AF (390) of the current status of the Sync Request. At this time, UE1, Sync Error Budget, Location, Range, etc. may be included.

[0104] In step 311, TSCTSF (385) can apply a Sync service to UE1. At this time, the request of TSCTSF can be delivered to AMF via PCF. AMF can apply this request to gNB1 to which UE1 belongs and only apply Sync service using RAN technology such as SIB broadcast and RRC signaling between gNB1 and UE1. Alternatively, TSCTSF can additionally apply a (g)PTP-based Sync service that periodically delivers Sync messages from NW-TT of UPF1 to DS-TT of UE1 at the same time as the Sync service using RAN technology by sending signals to NW-TT and DS-TT. This process is as described in Fig. 1.

[0105] In step 303a, TSCTSF (385) may request AMF2 (362) to notify UE2 (332) of its location and whether it belongs to an AoI. At this time, the UE's location may be converted and used as a TA ID list known to 3GPP.

[0106] At step 304a, AMF2 (362) can notify TSCTSF / NEF (385) whether UE2's current location and location meet the coverage conditions and that it is subscribed.

[0107] In step 305a, TSCTSF / NEF (385) can report the current status of the Sync Request to AF (390). At this time, UE2, Sync Error Budget, Coverage Condition, etc. can be included.

[0108] In step 306a, AF can use the report from step 305a to re-verify whether the Sync Error Budget or Coverage conditions are satisfied, and if necessary, send a modified Sync Service Request to TSCTSF / NEF (385).

[0109] At step 307a, AF (390) may send a modified Sync service request to TSCTSF / NEF (385). At this time, UE2, Sync Error Budget, and Coverage Condition may be included.

[0110] At step 308a, TSCTSF (385) can check again whether the coverage condition is satisfied.

[0111] In step 309a, TSCTSF (385) can check again whether the requested Sync Error Budget can be satisfied through the RAN's Sync Error Budget transmitted through AMF2 (362).

[0112] In step 310a, TSCTSF / NEF (385) may notify AF (390) of the current status of the Sync Request. At this time, UE2, Sync Error Budget, Location, Range, etc. may be included.

[0113] In step 311a, TSCTSF (385) can apply a Sync service to UE2. At this time, the request of TSCTSF can be delivered to AMF2 via PCF. AMF2 can apply this request to gNB2 to which UE2 belongs, and can only apply a Sync service using RAN technology such as SIB broadcast and RRC signaling between gNB2 and UE2. Alternatively, TSCTSF can additionally apply a (g)PTP-based Sync service that periodically delivers Sync messages from NW-TT of UPF2 to DS-TT of UE2 at the same time as the Sync service using RAN technology by sending signals to NW-TT and DS-TT. This process is as described in Fig. 1.

[0114]

[0115] Figure 3b is a diagram showing the operation when an AMF handover occurs among the Area of ​​Interest subscriptions for each UE of the Sync service target group.

[0116] Referring to Figure 3b, when a UE moves beyond the AMF area, Subscription / De-Subscription signaling for the Area of ​​Interest subscription may also occur simultaneously. In this case, as the number of UEs within a group identified by Group ID increases or the mobility of the UE increases, both the signaling load and the signaling load may increase, which may become problematic.

[0117] In step 312, UE1 (331) moves from gNB1 (341) to gNB3 (343), moves from the area of ​​AMF1 (361) to the area of ​​AMF3 (363), and performs registration in AMF3 (363).

[0118] In step 313, UE context information can be transferred between AMF1 (361) and AMF3 (363) according to the handover of UE1.

[0119] In step 314, UDM / UDR (380) can notify TSCTSF (385) that an update has occurred due to a change in AMF of UE1. That is, UDM / UDR (380) can notify TSCTSF (385) that the location where UE1 (331) is registered has changed from AMF1 (361) to AMF3 (363).

[0120] In step 315, AMF1 (361) can notify TSCTSF (385) of a change in location of UE1. At this time, UE1, Coverage (list of TAs) can be included.

[0121] In step 316, TSCTSF (385) can release UE1's location notification subscription to AMF1 (361). At this time, the De-Subscription request can include UE1, Location, and Coverage.

[0122] In step 317, TSCTSF (385) may request a location notification subscription for UE1 from AMF3 (363). At this time, the subscription request may include UE1, Location, and Coverage.

[0123] At step 318, AMF3 (363) can notify TSCTSF / NEF (385) whether UE1's current location and location meet the coverage conditions and that it is subscribed.

[0124] In step 319, TSCTSF / NEF (385) can report the current status of the Sync Request to AF (390). At this time, UE1, Sync Error Budget, Coverage Condition, etc. can be included.

[0125] In step 320, AF (390) can use the report of step 319 to re-check whether the Sync Error Budget or Coverage conditions are satisfied, and if necessary, send a modified Sync service request to TSCTSF / NEF (385).

[0126] At step 321, AF (390) may send a modified Sync service request to TSCTSF / NEF (385). At this time, UE1, Sync Error Budget, and Coverage Condition may be included.

[0127] At step 322, TSCTSF (385) can check again whether the coverage condition is satisfied.

[0128] In step 323, TSCTSF (385) can check again whether the requested Sync Error Budget can be satisfied through the RAN's Sync Error Budget transmitted through AMF1 (361).

[0129] In step 324, TSCTSF / NEF (385) may notify AF (390) of the current status of the Sync Request. At this time, UE1, Sync Error Budget, Location, Range, etc. may be included.

[0130] In step 325, TSCTSF (385) can apply a Sync service to UE1. At this time, the request of TSCTSF can be delivered to AMF via PCF. AMF can apply this request to gNB1 to which UE1 belongs and only apply Sync service using RAN technology such as SIB broadcast and RRC signaling between gNB1 and UE1. Alternatively, TSCTSF can additionally apply a (g)PTP-based Sync service that periodically delivers Sync messages from NW-TT of UPF1 to DS-TT of UE1 at the same time as the Sync service using RAN technology by sending signals to NW-TT and DS-TT. This process is as described in Fig. 1.

[0131]

[0132] Figures 4a and 4b are diagrams showing Area of ​​Interest subscription for a UE of a Sync service target DNN / S-NSSAI.

[0133] Referring to FIGS. 4a and 4b, when a Sync service has a coverage condition and its target is UEs having DNN / -S-NSSAI, 5GS can request an Area of ​​Interest for each UE from AMF.

[0134] At step 400, UE1 (431) can connect to gNB1 (441) and register with AMF1 (461). At this time, UE Capability, Cell ID / RAN ID / TA ID / SA ID, etc. may be included. AMF1 (461), which receives the Registration Request from UE1 (431), can verify subscriber information through UDM and store the related Subscription Context in AMF. In addition, AMF sends the related Context to gNB1 (441) and sends the remaining Registration Response to UE1 (431) to complete the remaining Registration process. Subsequently, UE1 can establish a PDU Session for DNN and S-NSSAI.

[0135] At step 400a, UE2 (432) can connect to gNB2 (442) and register with AMF2 (462). At this time, UE Capability, Cell ID / RAN ID / TA ID / SA ID, etc. may be included. AMF2 (462), which receives the Registration Request from UE2 (432), can check subscriber information through UDM and store the related Subscription Context in AMF. In addition, AMF sends the related Context to gNB2 (442) and sends the remaining Registration Response to UE2 (432) to complete the remaining Registration process. Subsequently, UE2 (432) can establish a PDU Session for DNN and S-NSSAI.

[0136] In step 401, the AF (490) can send a 5GS Sync Request for target UEs to the TSCTSF (Time Sensitive Communications and Time Synchronization Function) / NEF (Network Exposure Function) (485). This Request can include the required Synchronization Accuracy as a Sync Error Budget. In addition, it can specify the Coverage to which the Sync Service should be applied. The indication of the target UE can be expressed as a UE ID list, a Group ID, or a DNN (Data Network Name) / S-NSSAI (Single Network Slice Selection Assistance Information). In addition, an RA Adjust Request can also be included. At this time, the TSCTSF / NEF can derive TA IDs that meet the coverage conditions and manage them as a TA List. In this example, the targets of the Sync service are UEs having a DNN / -S-NSSAI.

[0137] In step 402, TSCTSF / NEF (485) can identify the AMF in which each UE with a PDU Session corresponding to the DNN and S-NSSAI combination in the UDM is registered. In this step, NRF can also be used to identify the location information of the AMF. For example, TSCTSF (485) can identify that UE1 is located in AMF1 and UE2 is located in AMF2. In this step, TSCTSF (485) can also request to be notified if the AMF in which the UEs are located has changed. Afterwards, TSCTSF (485) can request the Area of ​​Interest for each UE from each AMF.

[0138] In step 403, TSCTSF (485) may request AMF1 (461) to report information about UE1's location and whether it belongs to an AoI. At this time, the UE's location may be converted and used using a list of TA IDs known to 3GPP.

[0139] At step 404, AMF1 (461) can notify TSCTSF / NEF (485) whether UE1's current location and location meet the coverage conditions and that it is subscribed.

[0140] In step 405, TSCTSF / NEF (485) can report the current status of the Sync Request to AF (490). This may include UE1, Sync Error Budget, Coverage Condition, etc.

[0141] In step 406, AF can use the report from step 405 to re-verify whether the Sync Error Budget or Coverage conditions are met, and if necessary, send a modified Sync Service Request to TSCTSF / NEF (485).

[0142] At step 407, AF (490) may send a modified Sync service request to TSCTSF / NEF (485). At this time, UE1, Sync Error Budget, and Coverage Condition may be included.

[0143] At step 408, TSCTSF (485) can check again whether the coverage condition is satisfied.

[0144] In step 409, TSCTSF (485) can check again whether the requested Sync Error Budget can be satisfied through the RAN's Sync Error Budget transmitted through AMF1 (461).

[0145] In step 410, TSCTSF / NEF (485) may notify AF (490) of the current status of the Sync Request. This may include UE1, Sync Error Budget, Location, Range, etc.

[0146] In step 411, TSCTSF (485) can apply a Sync service to UE1. At this time, the request of TSCTSF can be delivered to AMF through PCF. AMF can apply this request to gNB1 to which UE1 belongs and only apply Sync service using RAN technology such as SIB broadcast and RRC signaling between gNB1 and UE1. Alternatively, TSCTSF can additionally apply a (g)PTP-based Sync service that periodically delivers Sync messages from NW-TT of UPF1 to DS-TT of UE1 at the same time as the Sync service using RAN technology by sending signals to NW-TT and DS-TT. This process is as described in Fig. 1.

[0147] In step 403a, TSCTSF (485) may request AMF2 (462) to notify UE2 (432) of its location and whether it belongs to an AoI. At this time, the UE's location may be converted and used using a TA ID list known to 3GPP.

[0148] At step 404a, AMF2 (462) can notify TSCTSF / NEF (485) that UE2's current location and location meet the coverage conditions and that it is subscribed.

[0149] At step 405a, TSCTSF / NEF (485) can report the current status of the Sync Request to AF (490). This may include UE2, Sync Error Budget, Coverage Condition, etc.

[0150] In step 406a, AF can use the report from step 405a to re-verify whether the Sync Error Budget or Coverage conditions are met, and if necessary, send a modified Sync Service Request to TSCTSF / NEF (485).

[0151] At step 407a, AF (490) may send a modified Sync service request to TSCTSF / NEF (485). At this time, UE2, Sync Error Budget, and Coverage Condition may be included.

[0152] At step 408a, TSCTSF (485) can check again whether the coverage condition is satisfied.

[0153] In step 409a, TSCTSF (485) can check again whether the requested Sync Error Budget can be satisfied through the RAN's Sync Error Budget transmitted through AMF2 (462).

[0154] At step 410a, TSCTSF / NEF (485) may notify AF (490) of the current status of the Sync Request. This may include UE2, Sync Error Budget, Location, Range, etc.

[0155] In step 411a, TSCTSF (485) can apply a Sync service to UE2. At this time, the request of TSCTSF can be delivered to AMF2 via PCF. AMF2 can apply this request to gNB2 to which UE2 belongs, and can only apply a Sync service using RAN technology such as SIB broadcast and RRC signaling between gNB2 and UE2. Alternatively, TSCTSF can additionally apply a (g)PTP-based Sync service that periodically delivers Sync messages from NW-TT of UPF2 to DS-TT of UE2 at the same time as the Sync service using RAN technology by sending signals to NW-TT and DS-TT. This process is as described in Fig. 1.

[0156]

[0157] Figure 4c is a diagram showing the operation when an AMF-to-AMF handover occurs during an Area of ​​Interest subscription for a UE of a Sync service target DNN / S-NSSAI.

[0158] Referring to Figure 4c, when a UE moves beyond the AMF area, Subscription / De-Subscription signaling for the Area of ​​Interest subscription may also occur simultaneously. In this case, as the number of UEs within a group identified by Group ID increases or the mobility of the UE increases, both the signaling load and the signaling load may increase, which may become problematic.

[0159] At step 412, UE1 (431) moves from gNB1 (441) to gNB3 (443), and then moves from the area of ​​AMF1 (461) to the area of ​​AMF3 (463) to perform registration in AMF3 (463). Since changes may follow in the UPF and SMF, PDU Session Modification of UE1 for DNN and S-NSSAI may also be performed.

[0160] In step 413, UE context information can be transferred between AMF1 (461) and AMF3 (463) according to the handover of UE1.

[0161] In step 414, UDM / UDR (480) can notify TSCTSF (485) that an update has occurred due to a change in AMF of UE1. That is, UDM / UDR (480) can notify TSCTSF (485) that the location where UE1 (431) is registered has changed from AMF1 (461) to AMF3 (463).

[0162] In step 415, AMF1 (461) may notify TSCTSF (485) of a change in location of UE1. At this time, UE1, Coverage (list of TAs) may be included.

[0163] In step 416, TSCTSF (485) can release UE1's location notification subscription to AMF1 (461). At this time, the De-Subscription request can include UE1, Location, and Coverage.

[0164] In step 417, TSCTSF (485) may request a location notification subscription for UE1 from AMF3 (463). At this time, the subscription request may include UE1, Location, and Coverage.

[0165] At step 418, AMF3 (463) can notify TSCTSF / NEF (485) whether UE1's current location and location meet the coverage conditions and that it is subscribed.

[0166] In step 419, TSCTSF / NEF (485) can report the current status of the Sync Request to AF (490). This may include UE1, Sync Error Budget, Coverage Condition, etc.

[0167] In step 420, AF (490) can use the report of step 419 to recheck whether the Sync Error Budget or Coverage conditions are satisfied, and if necessary, send a modified Sync service request to TSCTSF / NEF (485).

[0168] At step 421, AF (490) may send a modified Sync service request to TSCTSF / NEF (485). At this time, UE1, Sync Error Budget, and Coverage Condition may be included.

[0169] At step 422, TSCTSF (485) can check again whether the coverage condition is satisfied.

[0170] In step 423, TSCTSF (485) can check again whether the requested Sync Error Budget can be satisfied through the RAN's Sync Error Budget transmitted through AMF1 (461).

[0171] In step 424, TSCTSF / NEF (485) may notify AF (490) of the current status of the Sync Request. At this time, UE1, Sync Error Budget, Location, Range, etc. may be included.

[0172] In step 425, TSCTSF (485) can apply a Sync service to UE1. At this time, the request of TSCTSF can be delivered to AMF via PCF. AMF can apply this request to gNB1 to which UE1 belongs and only apply Sync service using RAN technology such as SIB broadcast and RRC signaling between gNB1 and UE1. Alternatively, TSCTSF can additionally apply a (g)PTP-based Sync service that sends signals to NW-TT and DS-TT, thereby periodically delivering Sync messages from NW-TT of UPF1 to DS-TT of UE1 simultaneously with the Sync service using RAN technology. This process is as described in Fig. 1.

[0173]

[0174] In order to prevent AoI Subscribe / De-Subscribe signaling from occurring during handover, the AMF can be found at once by referring to the coverage conditions and conditions of multiple target UEs during the Sync Request, and while performing AoI Subscription, the corresponding UEs can be prevented from subscribing / de-subscribing to AoI during handover within the coverage conditions. While performing AoI Subscription, the All-AMF Indication can be additionally applied so that the corresponding UEs do not subscribe / de-subscribe to AoI during handover within the coverage conditions.

[0175]

[0176] FIG. 5a and FIG. 5b are diagrams showing the operation when All-AMF Indication is applied to the Area of ​​Interest subscription for each UE in the Sync service target UE list.

[0177] Referring to FIG. 5a and FIG. 5b, it is possible to simultaneously find AMFs and perform AoI Subscription so that the corresponding UEs do not subscribe / de-subscribe to AoI during handover within coverage conditions. It is also possible to additionally apply All-AMF Indication so that the corresponding UEs do not subscribe / de-subscribe to AoI during handover within coverage conditions while performing AoI Subscription.

[0178] At step 500, UE1 (531) can connect to gNB1 (541) and register with AMF1 (561). At this time, UE Capability, Cell ID / RAN ID / TA ID / SA ID, etc. may be included. AMF1 (561), which receives the Registration Request from UE1 (531), can verify subscriber information through UDM and store the related Subscription Context in AMF. In addition, it sends the related Context to gNB1 (541), sends the remaining Registration Response to UE1 (531), and completes the remaining Registration process.

[0179] At step 500a, UE2 (532) can connect to gNB2 (542) and register with AMF2 (562). At this time, UE Capability, Cell ID / RAN ID / TA ID / SA ID, etc. may be included. AMF2 (562), which receives the Registration Request from UE2 (532), can verify subscriber information through UDM and store the related Subscription Context in AMF. In addition, AMF sends the related Context to gNB2 (542) and sends the remaining Registration Response to UE2 (532) to complete the remaining Registration process.

[0180] In step 501, the AF (590) can send a 5GS Sync Request for target UEs to the TSCTSF (Time Sensitive Communications and Time Synchronization Function) / NEF (Network Exposure Function) (585). This Request can include the required Synchronization Accuracy as a Sync Error Budget. In addition, it can specify the Coverage to which the Sync Service should be applied. The indication of the target UE can be expressed as a UE ID list, a Group ID, or a DNN (Data Network Name) / S-NSSAI (Single Network Slice Selection Assistance Information). In addition, an RA Adjust Request can also be included. At this time, the TSCTSF / NEF can derive TA IDs that meet the coverage conditions and manage them as a TA List. In this example, the target of the Sync service is provided as a UE List. You can include the All-AMF Indication in the AF's Sync Request to find AMFs all at once, subscribe to AoI, and prevent the corresponding UEs from subscribing / de-subscribing to AoI during handover within coverage conditions. You can also implicitly replace the All-AMF Indication instead of including the All-AMF Indication. For example, if the number of UEs in the UE list exceeds a certain threshold, the All-AMF Indication can be replaced. In another example, if certain UEs are included, the All-AMF Indication can be replaced. Or, depending on the UE Type, the All-AMF Indication can be replaced.

[0181] In step 502, the TSCTSF / NEF (585) discovers all AMFs that satisfy the Coverage Condition through the UDM and can identify the AMF in which each target UE is registered. In this step, the NRF can also be used to identify the location information of the AMF. For example, the TSCTSF (585) can identify that the AMFs that satisfy the Coverage Condition are AMF1, AMF2, and AMF3, and that UE1 is located in AMF1 and UE2 is located in AMF2. In this step, the TSCTSF (585) can also request to be notified if the AMF in which the UEs are located has changed. Afterwards, the TSCTSF (585) can request the Area of ​​Interest for each UE from each AMF.

[0182] In step 503, TSCTSF (585) may request AMF1 (561) to notify the location and AoI information for the UE list (UE1, UE2). At this time, the location of the UE may be converted and used as a TA ID list known to 3GPP. All-AMF Indication may be included in this step. All-AMF Indication may not be included and may be implicitly replaced with All-AMF Indication. For example, if the number of UEs in the UE list exceeds a certain standard, All-AMF Indication may be replaced. In another example, if specific UEs are included, All-AMF Indication may be replaced. Or, depending on the UE Type, All-AMF Indication may be replaced.

[0183] In step 503a, TSCTSF (585) may request AMF2 (562) to notify the location and AoI information for the UE list (UE1, UE2). At this time, the location of the UE may be converted and used as a TA ID list known to 3GPP. All-AMF Indication may be included in this step. All-AMF Indication may not be included and may be implicitly replaced with All-AMF Indication. For example, if the number of UEs in the UE list exceeds a certain threshold, All-AMF Indication may be replaced. In another example, if specific UEs are included, All-AMF Indication may be replaced. Or, depending on the UE Type, All-AMF Indication may be replaced.

[0184] In step 503b, TSCTSF (585) may request AMF3 (563) to notify the location and AoI information for the UE list (UE1, UE2). At this time, the location of the UE may be converted and used as a TA ID list known to 3GPP. All-AMF Indication may be included in this step. All-AMF Indication may not be included and may be implicitly replaced with All-AMF Indication. For example, if the number of UEs in the UE list exceeds a certain threshold, All-AMF Indication may be replaced. In another example, if specific UEs are included, All-AMF Indication may be replaced. Or, depending on the UE Type, All-AMF Indication may be replaced.

[0185] At step 504, AMF1 (561) can notify TSCTSF / NEF (585) whether UE1's current location and location meet the coverage conditions and that it is subscribed.

[0186] In step 505, TSCTSF / NEF (585) can report the current status of the Sync Request to AF (590). This may include UE1, Sync Error Budget, Coverage Condition, etc.

[0187] In step 506, AF (590) can use the report of step 505 to re-check whether the Sync Error Budget or Coverage conditions are satisfied, and if necessary, send a modified Sync service request to TSCTSF / NEF (585).

[0188] At step 507, AF (590) may send a modified Sync service request to TSCTSF / NEF (585). At this time, UE1, Sync Error Budget, and Coverage Condition may be included.

[0189] At step 508, TSCTSF (585) can check again whether the coverage condition is satisfied.

[0190] In step 509, TSCTSF (585) can check again whether the requested Sync Error Budget can be satisfied through the RAN's Sync Error Budget transmitted through AMF1 (561).

[0191] In step 510, TSCTSF / NEF (585) may notify AF (590) of the current status of the Sync Request. This may include UE1, Sync Error Budget, Location, Range, etc.

[0192] In step 511, TSCTSF (585) can apply a Sync service to UE1. At this time, the request of TSCTSF can be delivered to AMF via PCF. AMF can apply this request to gNB1 to which UE1 belongs and only apply Sync service using RAN technology such as SIB broadcast and RRC signaling between gNB1 and UE1. Alternatively, TSCTSF can additionally apply a (g)PTP-based Sync service that periodically delivers Sync messages from NW-TT of UPF1 to DS-TT of UE1 at the same time as the Sync service using RAN technology by sending signals to NW-TT and DS-TT. This process is as described in Fig. 1.

[0193] At step 504a, AMF2 (562) can notify TSCTSF / NEF (585) whether UE2's current location and location meet the coverage conditions and that it is subscribed.

[0194] At step 505a, TSCTSF / NEF (585) can report the current status of the Sync Request to AF (590). This may include UE2, Sync Error Budget, Coverage Condition, etc.

[0195] In step 506a, AF (590) can use the report of step 505a to re-check whether the Sync Error Budget or Coverage conditions are satisfied, and if necessary, send a modified Sync service request to TSCTSF / NEF.

[0196] At step 507a, AF (590) may send a modified Sync service request to TSCTSF / NEF (585). At this time, UE2, Sync Error Budget, and Coverage Condition may be included.

[0197] At step 508a, TSCTSF (585) can check again whether the coverage condition is satisfied.

[0198] In step 509a, TSCTSF (585) can check again whether the requested Sync Error Budget can be satisfied through the RAN's Sync Error Budget transmitted through AMF2 (562).

[0199] In step 510a, TSCTSF / NEF (585) may notify AF (590) of the current status of the Sync Request. This may include UE2, Sync Error Budget, Location, Range, etc.

[0200] In step 511a, TSCTSF (585) can apply a Sync service to UE2. At this time, the request of TSCTSF can be delivered to AMF2 via PCF. AMF2 can apply this request to gNB2 to which UE2 belongs, and can only apply a Sync service using RAN technology such as SIB broadcast and RRC signaling between gNB2 and UE2. Alternatively, TSCTSF can additionally apply a (g)PTP-based Sync service that periodically delivers Sync messages from NW-TT of UPF2 to DS-TT of UE2 at the same time as the Sync service using RAN technology by sending signals to NW-TT and DS-TT. This process is as described in Fig. 1.

[0201]

[0202] Figure 5c is a diagram showing the operation when an inter-AMF handover occurs when the Area of ​​Interest subscription for each UE in the Sync service target UE list is applied with All-AMF Indication.

[0203] Referring to Fig. 5c, when a UE moves beyond the AMF area, Subscription / De-Subscription signaling of Area of ​​Interest subscription also occurs simultaneously. In this case, if the number of target UEs increases or the mobility of the UEs increases, both the signaling load and the load may increase, which may become a problem. Through the process of Fig. 5a, when the Sync service has a coverage condition and the target is the UEs specified in the UE List, 5GS can find the AMF all at once and perform AoI Subscription while preventing the corresponding UEs from subscribing / de-subscribing to AoI during handover within the coverage condition. When performing AoI Subscription, All-AMF Indication can be additionally applied so that the corresponding UEs do not subscribe / de-subscribe to AoI during handover within the coverage condition.

[0204] In step 512, UE1 (531) moves from gNB1 (541) to gNB3 (543), moves from the area of ​​AMF1 (561) to the area of ​​AMF3 (563), and performs registration in AMF3 (543).

[0205] In step 513, UE context information can be transferred between AMF1 (561) and AMF3 (563) according to the handover of UE1.

[0206] In step 514, UDM / UDR (580) can notify TSCTSF (585) that an update has occurred due to a change in AMF of UE1. That is, UDM / UDR (580) can notify TSCTSF (585) that the location where UE1 (531) is registered has changed from AMF1 (561) to AMF3 (563).

[0207] At step 515, AMF1 (561) may notify TSCTSF (585) of a location change of UE1. At this time, UE1 and Coverage (list of TAs) may be included. At this time, unlike FIG. 2b, TSCTSF does not release the location notification subscription of UE1 from AMF1.

[0208] At step 516, AMF3 (563) can notify TSCTSF / NEF (585) whether UE1's current location and location meet the coverage conditions and that it has been subscribed. At this time, unlike in FIG. 2b, no signaling occurs where TSCTSF requests AMF3 to subscribe to UE1's location notification.

[0209] In step 517, TSCTSF / NEF (585) may report the current status of the Sync Request to AF (590). This may include UE1, Sync Error Budget, Coverage Condition, etc.

[0210] In step 518, AF (590) can use the report of step 517 to re-check whether the Sync Error Budget or Coverage conditions are satisfied, and if necessary, send a modified Sync service request to TSCTSF / NEF (585).

[0211] At step 519, AF (590) may send a modified Sync service request to TSCTSF / NEF (585). At this time, UE1, Sync Error Budget, and Coverage Condition may be included.

[0212] At step 520, TSCTSF (585) can check again whether the coverage condition is satisfied.

[0213] In step 521, TSCTSF (585) can check again whether the requested Sync Error Budget can be satisfied through the RAN's Sync Error Budget transmitted through AMF1 (561).

[0214] In step 522, TSCTSF / NEF (585) may notify AF (590) of the current status of the Sync Request. At this time, UE1, Sync Error Budget, Location, Range, etc. may be included.

[0215] In step 523, TSCTSF (585) can apply a Sync service to UE1. At this time, the request of TSCTSF can be delivered to AMF via PCF. AMF can apply this request to gNB1 to which UE1 belongs and only apply Sync service using RAN technology such as SIB broadcast and RRC signaling between gNB1 and UE1. Alternatively, TSCTSF can additionally apply a (g)PTP-based Sync service that periodically delivers Sync messages from NW-TT of UPF1 to DS-TT of UE1 at the same time as the Sync service using RAN technology by sending signals to NW-TT and DS-TT. This process is as described in Fig. 1.

[0216]

[0217] Figures 6a and 6b are diagrams showing the operation when All-AMF Indication is applied to the Area of ​​Interest subscription for each UE of the Sync service target group.

[0218] Referring to FIGS. 6a and 6b, when a Sync service has a coverage condition and its target is a UE List as an Internal Group Identifyer, 5GS can find AMF all at once and, while performing AoI Subscription, prevent the corresponding UEs from subscribing / de-subscribing to AoI during handover within the coverage condition. While performing AoI Subscription, All-AMF Indication can be additionally applied so that the corresponding UEs do not subscribe / de-subscribe to AoI during handover within the coverage condition.

[0219] At step 600, UE1 (631) can connect to gNB1 (641) and register with AMF1 (661). At this time, UE Capability, Cell ID / RAN ID / TA ID / SA ID, etc. may be included. AMF1 (661), which receives the Registration Request from UE1 (631), can verify subscriber information through UDM and store the related Subscription Context in AMF. In addition, it sends the related Context to gNB1 (641), sends the remaining Registration Response to UE1 (631), and completes the remaining Registration process.

[0220] At step 600a, UE2 (632) can connect to gNB2 (642) and register with AMF2 (662). At this time, UE Capability, Cell ID / RAN ID / TA ID / SA ID, etc. may be included. AMF2 (662), which receives the Registration Request from UE2 (632), can verify subscriber information through UDM and store the related Subscription Context in AMF. In addition, AMF sends the related Context to gNB2 (642) and sends the remaining Registration Response to UE2 (632), thereby completing the remaining Registration process.

[0221] In step 601, the AF (690) can send a 5GS Sync Request for target UEs to the TSCTSF (Time Sensitive Communications and Time Synchronization Function) / NEF (Network Exposure Function) (685). This Request can include the required Synchronization Accuracy as a Sync Error Budget. In addition, it can specify the Coverage to which the Sync Service should be applied. The indication of the target UE can be expressed as a UE ID list, a Group ID, or a DNN (Data Network Name) / S-NSSAI (Single Network Slice Selection Assistance Information). In addition, an RA Adjust Request can also be included. At this time, the TSCTSF / NEF can derive TA IDs that meet the coverage conditions and manage them as a TA List. In this example, the target of the Sync service is provided as a Group ID. The Group ID provided by AF is an External Group ID that can be used outside of 5GS, and NEF or TSCTSF can be converted to an Internal Group ID or converted to an Internal Group ID in UDM. When discovering AMF all at once and performing AoI Subscription, the All-AMF Indication can be included in the AF's Sync Request so that the corresponding UEs do not subscribe / de-subscribe to AoI during handover within the coverage conditions. The All-AMF Indication can also be replaced implicitly without including the All-AMF Indication. For example, the All-AMF Indication can be replaced when the number of UEs in the UE list exceeds a certain standard.For example, if specific UEs are included, it can replace the All-AMF Indication. Alternatively, it can replace the All-AMF Indication depending on the UE Type. Another example is if a specific Group ID is used, it can replace the All-AMF Indication. Alternatively, if multiple UEs are specified by a Group ID, it can replace the All-AMF Indication.

[0222] In step 602, the TSCTSF / NEF (685) discovers all AMFs that satisfy the Coverage Condition through the UDM and can identify the AMF to which each UE in a group distinguished by the Group ID is registered. In this step, the NRF can also be used to identify the location information of the AMF. For example, the TSCTSF (685) can identify that the AMFs that satisfy the Coverage Condition are AMF1, AMF2, and AMF3, and that UE1 is located in AMF1 and UE2 is located in AMF2. In this step, the TSCTSF (685) can also request to be notified if the AMFs where the UEs are located have changed. Afterwards, the TSCTSF (685) can request the Area of ​​Interest for each UE from each AMF.

[0223] In step 603, TSCTSF (685) may request AMF1 (661) to notify the location and AoI belonging information of UEs of a group distinguished by Group ID (Internal Group ID). At this time, the location of the UE may be converted and used as a TA ID list known to 3GPP. All-AMF Indication may be included in this step. All-AMF Indication may not be included and may be implicitly replaced with All-AMF Indication. For example, if the number of UEs in the UE list exceeds a certain standard, All-AMF Indication may be replaced. In another example, if specific UEs are included, All-AMF Indication may be replaced. Or, depending on the UE Type, All-AMF Indication may be replaced.

[0224] In step 603a, TSCTSF (685) may request AMF2 (662) to notify the location and AoI belonging to the UEs of the group distinguished by the Group ID (Internal Group ID). At this time, the location of the UE may be converted and used as a TA ID list known to 3GPP. All-AMF Indication may be included in this step. All-AMF Indication may not be included and may be implicitly replaced with All-AMF Indication. For example, if the number of UEs in the UE list exceeds a certain standard, All-AMF Indication may be replaced. In another example, if specific UEs are included, All-AMF Indication may be replaced. Or, depending on the UE Type, All-AMF Indication may be replaced.

[0225] In step 603b, TSCTSF (685) may request AMF3 (663) to notify the location and AoI belonging information of UEs in a group distinguished by Group ID (Internal Group ID). At this time, the location of the UE may be converted and used as a TA ID list known to 3GPP. All-AMF Indication may be included in this step. All-AMF Indication may not be included and may be implicitly replaced with All-AMF Indication. For example, if the number of UEs in the UE list exceeds a certain standard, All-AMF Indication may be replaced. In another example, if specific UEs are included, All-AMF Indication may be replaced. Or, depending on the UE Type, All-AMF Indication may be replaced.

[0226] At step 604, AMF1 (661) can notify TSCTSF / NEF (685) whether UE1's current location and location meet the coverage conditions and that it is subscribed.

[0227] In step 605, TSCTSF / NEF (685) may report the current status of the Sync Request to AF (690). This may include UE1, Sync Error Budget, Coverage Condition, etc.

[0228] In step 606, AF (690) can use the report of step 605 to re-check whether the Sync Error Budget or Coverage conditions are satisfied, and if necessary, send a modified Sync service request to TSCTSF / NEF (685).

[0229] At step 607, AF (690) may send a modified Sync service request to TSCTSF / NEF (685). At this time, UE1, Sync Error Budget, and Coverage Condition may be included.

[0230] At step 608, TSCTSF (685) can check again whether the coverage condition is satisfied.

[0231] In step 609, TSCTSF (685) can check again whether the requested Sync Error Budget can be satisfied through the RAN's Sync Error Budget transmitted through AMF1 (661).

[0232] In step 610, TSCTSF / NEF (685) may notify AF (690) of the current status of the Sync Request. This may include UE1, Sync Error Budget, Location, Range, etc.

[0233] In step 611, TSCTSF (685) can apply a Sync service to UE1. At this time, the request of TSCTSF can be delivered to AMF via PCF. AMF can apply this request to gNB1 to which UE1 belongs and only apply Sync service using RAN technology such as SIB broadcast and RRC signaling between gNB1 and UE1. Alternatively, TSCTSF can additionally apply a (g)PTP-based Sync service that periodically delivers Sync messages from NW-TT of UPF1 to DS-TT of UE1 at the same time as the Sync service using RAN technology by sending signals to NW-TT and DS-TT. This process is as described in Fig. 1.

[0234] At step 604a, AMF2 (662) can notify TSCTSF / NEF (685) that UE2's current location and location meet the coverage conditions and that it is subscribed.

[0235] At step 605a, TSCTSF / NEF (685) can report the current status of the Sync Request to AF (690). This may include UE2, Sync Error Budget, Coverage Condition, etc.

[0236] In step 606a, AF (690) can use the report of step 605a to re-check whether the Sync Error Budget or Coverage conditions are satisfied, and if necessary, send a modified Sync service request to TSCTSF / NEF.

[0237] At step 607a, AF (690) may send a modified Sync service request to TSCTSF / NEF (685). At this time, UE2, Sync Error Budget, and Coverage Condition may be included.

[0238] At step 608a, TSCTSF (685) can check again whether the coverage condition is satisfied.

[0239] In step 609a, TSCTSF (685) can check again whether the requested Sync Error Budget can be satisfied through the RAN's Sync Error Budget transmitted through AMF2 (662).

[0240] At step 610a, TSCTSF / NEF (685) may notify AF (690) of the current status of the Sync Request. This may include UE2, Sync Error Budget, Location, Range, etc.

[0241] In step 611a, TSCTSF (685) can apply a Sync service to UE2. At this time, the request of TSCTSF can be delivered to AMF2 via PCF. AMF2 can apply this request to gNB2 to which UE2 belongs, and can only apply a Sync service using RAN technology such as SIB broadcast and RRC signaling between gNB2 and UE2. Alternatively, TSCTSF can additionally apply a (g)PTP-based Sync service that periodically delivers Sync messages from NW-TT of UPF2 to DS-TT of UE2 at the same time as the Sync service using RAN technology by sending signals to NW-TT and DS-TT. This process is as described in Fig. 1.

[0242]

[0243] Figure 6c is a diagram showing the operation when an inter-AMF handover occurs when the Area of ​​Interest subscription for each UE of the Sync service target group is applied with the All-AMF Indication.

[0244] Referring to Fig. 6c, when a UE moves beyond the area of ​​the AMF, Subscription / De-Subscription signaling of the Area of ​​Interest subscription may also occur simultaneously. In this case, if the number of UEs within a group identified by the Group ID increases or the mobility of the UE increases, both the signaling load and the load may increase, which may become a problem. Through the process of Fig. 6a, when the Sync service has a coverage condition and the target is UEs within a group identified by the Group ID, the 5GS can find the AMF all at once and perform AoI Subscription while preventing the corresponding UEs from subscribing / de-subscribing to the AoI during a handover within the coverage condition. When performing AoI Subscription, the All-AMF Indication can be additionally applied so that the corresponding UEs do not subscribe / de-subscribe to the AoI during a handover within the coverage condition.

[0245] In step 612, UE1 (631) moves from gNB1 (641) to gNB3 (643), moves from the area of ​​AMF1 (661) to the area of ​​AMF3 (663), and performs registration in AMF3 (663).

[0246] In step 613, UE context information can be transferred between AMF1 (661) and AMF3 (663) according to the handover of UE1.

[0247] In step 614, UDM / UDR (680) can notify TSCTSF (685) that an update has occurred due to a change in AMF of UE1. That is, UDM / UDR (680) can notify TSCTSF (685) that the location where UE1 (631) is registered has changed from AMF1 (661) to AMF3 (663).

[0248] At step 615, AMF1 (661) may notify TSCTSF (685) of a location change of UE1. At this time, UE1 and Coverage (list of TAs) may be included. At this time, unlike FIG. 2b, TSCTSF does not release the location notification subscription of UE1 from AMF1.

[0249] At step 616, AMF3 (663) can notify TSCTSF / NEF (685) that UE1's current location and location meet the coverage conditions and that it has been subscribed. At this time, unlike in FIG. 2b, no signaling occurs from TSCTSF to AMF3 requesting UE1's location notification subscription.

[0250] In step 617, TSCTSF / NEF (685) may report the current status of the Sync Request to AF (690). This may include UE1, Sync Error Budget, Coverage Condition, etc.

[0251] In step 618, AF (690) can use the report of step 617 to re-check whether the Sync Error Budget or Coverage conditions are satisfied, and if necessary, send a modified Sync service request to TSCTSF / NEF (685).

[0252] At step 619, AF (690) may send a modified Sync service request to TSCTSF / NEF (685). At this time, UE1, Sync Error Budget, and Coverage Condition may be included.

[0253] At step 620, TSCTSF (685) can check again whether the coverage condition is satisfied.

[0254] In step 621, TSCTSF (685) can check again whether the requested Sync Error Budget can be satisfied through the RAN's Sync Error Budget transmitted through AMF1 (661).

[0255] In step 622, TSCTSF / NEF (685) may notify AF (690) of the current status of the Sync Request. This may include UE1, Sync Error Budget, Location, Range, etc.

[0256] In step 623, TSCTSF (685) can apply a Sync service to UE1. At this time, the request of TSCTSF can be delivered to AMF via PCF. AMF can apply this request to gNB1 to which UE1 belongs and only apply Sync service using RAN technology such as SIB broadcast and RRC signaling between gNB1 and UE1. Alternatively, TSCTSF can additionally apply a (g)PTP-based Sync service that periodically delivers Sync messages from NW-TT of UPF1 to DS-TT of UE1 at the same time as the Sync service using RAN technology by sending signals to NW-TT and DS-TT. This process is as described in Fig. 1.

[0257]

[0258] Figures 7a and 7b are diagrams showing the operation when All-AMF Indication is applied to the Area of ​​Interest subscription for each UE of the Sync service target DNN / S-NSSAI.

[0259] Referring to FIG. 7a and FIG. 7b, when a Sync service has a coverage condition and its targets are UEs with DNN / -S-NSSAI, 5GS can request the AMF for the Area of ​​Interest for each UE. When a Sync service has a coverage condition and its targets are UEs with a PDU Session for the DNN / S-NSSAI combination, 5GS can find the AMF all at once and, while performing an AoI Subscription, prevent the corresponding UEs from Subscribing / De-Subscribing to the AoI during a Handover within the Coverage Condition. While performing an AoI Subscription, All-AMF Indication can be additionally applied so that the corresponding UEs do not Subscribe / De-Subscribe to the AoI during a Handover within the Coverage Condition.

[0260] At step 700, UE1 (731) can connect to gNB1 (741) and register with AMF1 (761). At this time, UE Capability, Cell ID / RAN ID / TA ID / SA ID, etc. may be included. AMF1 (761), which receives the Registration Request from UE1 (731), can verify subscriber information through UDM and store the related Subscription Context in AMF. In addition, AMF sends the related Context to gNB1 (741) and sends the remaining Registration Response to UE1 (731) to complete the remaining Registration process. Subsequently, UE1 (731) can establish a PDU Session for DNN and S-NSSAI.

[0261] At step 700a, UE2 (732) can connect to gNB2 (742) and register with AMF2 (762). At this time, UE Capability, Cell ID / RAN ID / TA ID / SA ID, etc. may be included. AMF2 (762), which receives the Registration Request from UE2 (732), can verify subscriber information through UDM and store the related Subscription Context in AMF. In addition, it sends the related Context to gNB2 (742) and sends the remaining Registration Response to UE2 (732) to complete the remaining Registration process. Subsequently, UE2 (732) can establish a PDU Session for DNN and S-NSSAI.

[0262] In step 701, the AF (790) can send a 5GS Sync Request for target UEs to the TSCTSF (Time Sensitive Communications and Time Synchronization Function) / NEF (Network Exposure Function) (785). This Request can include the required Synchronization Accuracy as a Sync Error Budget. In addition, it can specify the Coverage to which the Sync Service should be applied. The indication of the target UE can be expressed as a UE ID list, a Group ID, or a DNN (Data Network Name) / S-NSSAI (Single Network Slice Selection Assistance Information). In addition, an RA Adjust Request can also be included. At this time, the TSCTSF / NEF can derive TA IDs that meet the coverage conditions and manage them as a TA List. In this example, the targets of the Sync service are UEs having a DNN / -S-NSSAI. The All-AMF Indication can be included in the AF's Sync Request to discover AMFs all at once, subscribe to AoIs, and prevent the corresponding UEs from subscribing / de-subscribing to AoIs during handovers within coverage conditions. Instead of including the All-AMF Indication, an implicit All-AMF Indication can be used instead. For example, if all UEs with a DNN / S-NSSAI PDU Session are targeted, the All-AMF Indication can be used instead.

[0263] In step 702, TSCTSF / NEF (785) discovers all AMFs that satisfy the Coverage Condition through UDM and can know the AMF in which each UE that has a PDU Session corresponding to the DNN and S-NSSAI combination is registered. In this step, NRF can also be used to know the location information of the AMF. For example, TSCTSF (785) can know that AMF1, AMF2, and AMF3 satisfy the Coverage Condition, and that UE1 is located in AMF1 and UE2 is located in AMF2. In this step, TSCTSF (785) can also request to be notified if the AMF in which the UEs are located has changed. Afterwards, TSCTSF (785) can request each AMF for the Area of ​​Interest for each UE.

[0264] In step 703, TSCTSF (785) may request AMF1 (761) to notify the location and AoI belonging information for UEs having PDU Sessions corresponding to the DNN / S-NSSAI combination. At this time, the location of the UE may be converted and used by using a TA ID list known to 3GPP. All-AMF Indication may be included in this step. Alternatively, All-AMF Indication may be implicitly replaced with it. For example, if targeting all UEs having PDU Sessions of DNN / S-NSSAI, All-AMF Indication may be replaced with it.

[0265] In step 703a, TSCTSF (785) may request AMF2 (762) to notify the location and AoI belonging to UEs having PDU Sessions corresponding to the DNN / S-NSSAI combination. At this time, the location of the UE may be converted and used by the TA ID list known to 3GPP. All-AMF Indication may be included in this step. Alternatively, All-AMF Indication may be implicitly replaced with it. For example, if targeting all UEs having PDU Sessions of DNN / S-NSSAI, All-AMF Indication may be replaced with it.

[0266] In step 703b, TSCTSF (785) may request AMF3 (763) to notify the location and AoI belonging to UEs having PDU Sessions corresponding to the DNN / S-NSSAI combination. At this time, the location of the UE may be converted and used by the TA ID list known to 3GPP. All-AMF Indication may be included in this step. Alternatively, All-AMF Indication may be implicitly replaced with it. For example, if targeting all UEs having PDU Sessions of DNN / S-NSSAI, All-AMF Indication may be replaced with it.

[0267] At step 704, AMF1 (761) can notify TSCTSF / NEF (785) whether UE1's current location and location meet the coverage conditions and that it is subscribed.

[0268] At step 705, TSCTSF / NEF (785) may report the current status of the Sync Request to AF (790). This may include UE1, Sync Error Budget, Coverage Condition, etc.

[0269] In step 706, AF (790) can use the report of step 705 to re-check whether the Sync Error Budget or Coverage conditions are satisfied, and if necessary, send a modified Sync service request to TSCTSF / NEF (785).

[0270] At step 707, AF (790) may send a modified Sync service request to TSCTSF / NEF (785). At this time, UE1, Sync Error Budget, and Coverage Condition may be included.

[0271] At step 708, TSCTSF (785) can check again whether the coverage condition is satisfied.

[0272] At step 709, TSCTSF (785) can check again whether the requested Sync Error Budget can be satisfied through the RAN's Sync Error Budget transmitted through AMF1 (761).

[0273] In step 710, TSCTSF / NEF (785) may notify AF (790) of the current status of the Sync Request. At this time, UE1, Sync Error Budget, Location, Range, etc. may be included.

[0274] In step 711, TSCTSF (785) can apply a Sync service to UE1. At this time, the request of TSCTSF can be delivered to AMF through PCF. AMF can apply this request to gNB1 to which UE1 belongs and only apply Sync service using RAN technology such as SIB broadcast and RRC signaling between gNB1 and UE1. Alternatively, TSCTSF can additionally apply a (g)PTP-based Sync service that sends signals to NW-TT and DS-TT to periodically deliver Sync messages from NW-TT of UPF1 to DS-TT of UE1 simultaneously with the Sync service using RAN technology. This process is as described in Fig. 1.

[0275] At step 703a, TSCTSF (785) may request AMF2 (762) to report information about UE2's location and whether it belongs to an AoI. At this time, the UE's location may be converted and used using a list of TA IDs known to 3GPP.

[0276] At step 704a, AMF2 (762) can notify TSCTSF / NEF (785) that UE2's current location and location meet the coverage conditions and that it is subscribed.

[0277] At step 705a, TSCTSF / NEF (785) can report the current status of the Sync Request to AF (790). This may include UE2, Sync Error Budget, Coverage Condition, etc.

[0278] In step 706a, AF (790) can use the report of step 705a to re-check whether the Sync Error Budget or Coverage conditions are satisfied, and if necessary, send a modified Sync service request to TSCTSF / NEF (785).

[0279] At step 707a, AF (790) may send a modified Sync service request to TSCTSF / NEF (785). At this time, UE2, Sync Error Budget, and Coverage Condition may be included.

[0280] At step 708a, TSCTSF (785) can check again whether the coverage condition is satisfied.

[0281] In step 709a, TSCTSF (785) can recheck whether the requested Sync Error Budget can be satisfied through the RAN's Sync Error Budget transmitted through AMF2 (762).

[0282] At step 710a, TSCTSF / NEF (785) may notify AF (790) of the current status of the Sync Request. This may include UE2, Sync Error Budget, Location, Range, etc.

[0283] In step 711a, TSCTSF (785) can apply a Sync service to UE2. At this time, the request of TSCTSF can be delivered to AMF2 via PCF. AMF2 can apply this request to gNB2 to which UE2 belongs and only apply a Sync service using RAN technology such as SIB broadcast and RRC signaling between gNB2 and UE2. Alternatively, TSCTSF can additionally apply a (g)PTP-based Sync service that periodically delivers Sync messages from NW-TT of UPF2 to DS-TT of UE2 at the same time as the Sync service using RAN technology by sending signals to NW-TT and DS-TT. This process is as described in Fig. 1.

[0284]

[0285] Figure 7c is a diagram showing the operation when an inter-AMF handover occurs when the Area of ​​Interest subscription for each UE of the Sync service target DNN / S-NSSAI is applied with the All-AMF Indication.

[0286] Referring to Fig. 7c, when a UE moves beyond the area of ​​the AMF, Subscription / De-Subscription signaling of the Area of ​​Interest subscription may also occur simultaneously. In this case, if the number of UEs having PDU Sessions for the DNN / S-NSSAI combination increases or the mobility of the UEs increases, both the signaling load and the signaling load may increase, which may become a problem. Through the process of Fig. 7a, when the Sync service has a coverage condition and the target is UEs having PDU Sessions for the DNN / S-NSSAI combination, the 5GS can find the AMF all at once and perform AoI Subscription while preventing the corresponding UEs from subscribing / de-subscribing to the AoI during handover within the coverage condition. When performing AoI Subscription, the All-AMF Indication can be additionally applied so that the corresponding UEs do not subscribe / de-subscribe to the AoI during handover within the coverage condition.

[0287] At step 712, UE1 (631) moves from gNB1 (641) to gNB3 (643), and moves from the area of ​​AMF1 (661) to the area of ​​AMF3 (663) to perform registration in AMF3 (663). Since changes may follow in the UPF and SMF, PDU Session Modification of UE1 for DNN and S-NSSAI is also performed.

[0288] In step 713, UE context information can be transferred between AMF1 (661) and AMF3 (663) according to the handover of UE1.

[0289] In step 714, UDM / UDR (780) can notify TSCTSF (785) that an update has occurred due to a change in AMF of UE1. That is, UDM / UDR (780) can notify TSCTSF (785) that the location where UE1 (731) is registered has changed from AMF1 (761) to AMF3 (763).

[0290] At step 715, AMF1 (761) may notify TSCTSF (785) of a location change of UE1. At this time, UE1 and Coverage (list of TAs) may be included. At this time, unlike FIG. 2b, TSCTSF does not release the location notification subscription of UE1 from AMF1.

[0291] At step 716, AMF3 (763) can notify TSCTSF / NEF (785) that UE1's current location and location meet the coverage conditions and that it has been subscribed. At this time, unlike in FIG. 2b, no signaling occurs from TSCTSF to AMF3 requesting UE1's location notification subscription.

[0292] In step 717, TSCTSF / NEF (785) may report the current status of the Sync Request to AF (790). This may include UE1, Sync Error Budget, Coverage Condition, etc.

[0293] In step 718, AF (790) can use the report of step 717 to recheck whether the Sync Error Budget or Coverage conditions are satisfied, and if necessary, send a modified Sync service request to TSCTSF / NEF (785).

[0294] At step 719, AF (790) may send a modified Sync service request to TSCTSF / NEF (785). At this time, UE1, Sync Error Budget, and Coverage Condition may be included.

[0295] At step 720, TSCTSF (785) can check again whether the coverage condition is satisfied.

[0296] In step 721, TSCTSF (785) can check again whether the requested Sync Error Budget can be satisfied through the RAN's Sync Error Budget transmitted through AMF1 (761).

[0297] In step 722, TSCTSF / NEF (785) may notify AF (790) of the current status of the Sync Request. This may include UE1, Sync Error Budget, Location, Range, etc.

[0298] In step 723, TSCTSF (785) can apply a Sync service to UE1. At this time, the request of TSCTSF can be delivered to AMF via PCF. AMF can apply this request to gNB1 to which UE1 belongs and only apply Sync service using RAN technology such as SIB broadcast and RRC signaling between gNB1 and UE1. Alternatively, TSCTSF can additionally apply a (g)PTP-based Sync service that periodically delivers Sync messages from NW-TT of UPF1 to DS-TT of UE1 at the same time as the Sync service using RAN technology by sending signals to NW-TT and DS-TT. This process is as described in Fig. 1.

[0299]

[0300] Figure 8 is a diagram illustrating the structure of a terminal according to one embodiment of the present invention.

[0301] Referring to FIG. 8, the base station may include a transceiver (810), a control unit (820), and a storage unit (830). In the present invention, the control unit may be defined as a circuit or an application-specific integrated circuit or at least one processor.

[0302] The transceiver (810) can transmit and receive signals with other network entities. The transceiver (810) can transmit system information to a terminal, for example, and can transmit a synchronization signal or a reference signal.

[0303] The control unit (820) can control the overall operation of the base station according to the embodiment proposed in the present invention. For example, the control unit (820) can control the signal flow between each block to perform operations according to the flowchart described above. Specifically, the control unit (820) can control the operation proposed in the present invention to transmit residual system information (RMSI) in a multi-beam-based system according to the embodiment of the present invention.

[0304] The storage unit (830) can store at least one of the information transmitted and received through the transmission and reception unit (810) and the information generated through the control unit (820).

[0305]

[0306] FIG. 9 is a diagram illustrating the structure of a network entity according to one embodiment of the present invention.

[0307] Referring to FIG. 9, a network entity may include a transceiver (910), a control unit (920), and a storage unit (930). In the present invention, the control unit may be defined as a circuit or an application-specific integrated circuit or at least one processor.

[0308] The transceiver (910) can transmit and receive signals with other network entities. The transceiver (910) can transmit system information to a terminal, for example, and can transmit a synchronization signal or a reference signal.

[0309] The control unit (920) can control the overall operation of the base station according to the embodiment proposed in the present invention. For example, the control unit (920) can control the signal flow between each block to perform operations according to the flowchart described above. Specifically, the control unit (920) can control the operation proposed in the present invention to transmit residual system information (RMSI) in a multi-beam-based system according to the embodiment of the present invention.

[0310] The storage unit (930) can store at least one of the information transmitted and received through the transmission and reception unit (910) and the information generated through the control unit (920).

[0311]

[0312] The methods according to the embodiments described in the claims or specification of the present invention may be implemented in the form of hardware, software, or a combination of hardware and software.

[0313] When implemented in software, a computer-readable storage medium storing one or more programs (software modules) may be provided. The one or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. The one or more programs include instructions that cause the electronic device to execute methods according to the embodiments described in the claims or specification of the present invention.

[0314] These programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, read only memory (ROM), electrically erasable programmable read only memory (EEPROM), magnetic disc storage device, compact disc ROM (CD-ROM), digital versatile discs (DVDs) or other forms of optical storage device, magnetic cassette. Or, they may be stored in a memory configured as a combination of some or all of these. In addition, each configuration memory may be included in multiple numbers.

[0315] Additionally, the program may be stored in an attachable storage device that is accessible via a communication network such as the Internet, an intranet, a local area network (LAN), a wide local area network (WLAN), a storage area network (SAN), or a combination thereof. Such a storage device may be connected to a device implementing an embodiment of the present invention via an external port. Additionally, a separate storage device on the communication network may be connected to a device implementing an embodiment of the present invention.

[0316]

[0317] In the specific embodiments of the present invention described above, components included in the invention are expressed in the singular or plural form depending on the specific embodiment presented. However, the singular or plural expressions are selected to suit the presented situation for convenience of explanation, and the present invention is not limited to singular or plural components. Even components expressed in the plural form may be composed of singular elements, or even components expressed in the singular form may be composed of plural elements.

[0318] While the detailed description of the present invention has described specific embodiments, it is clear that various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the following claims but also by equivalents thereof.

Claims

1. In a TSCTSF (Time Sensitive Communication Time Synchronization Function) method in a wireless communication system, A step of receiving a message related to synchronization from an AF (Application Function); A step of discovering at least one Access and Mobility Management Function (AMF) through a network entity; A step of transmitting a first message containing information about UEs (User equipments) to at least one AMF; and A method characterized by comprising the step of receiving a second message including information about an Area of ​​interest (AOI) based on information about the UEs from at least one AMF.

2. In paragraph 1, A method, characterized in that the information about the UEs includes at least one of a UE identifier (ID) list, a group ID, or a DNN (Data Network Name) / S-NSSAI (Single Network Slice Selection Assistance Information).

3. In paragraph 1, A method characterized by further comprising a step of discovering at least one AMF based on a coverage condition included in a message related to said synchronization through said network entity.

4. In paragraph 1, A method characterized in that the information about the above UEs includes information about all AMFs.

5. A method performed by AMF (Access and Mobility Management Function) in a wireless communication system, A step of receiving a first message including information about UEs (User equipments) from a TSCTSF (Time Sensitive Communication Time Synchronization Function); A step of checking whether the conditions included in the information about the above UEs are satisfied; and A step of transmitting a second message including information about an Area of ​​interest (AOI) based on information about the UEs to the above TSCTSF, The above AMF is discovered through network entities, A method, characterized in that a message related to synchronization is transmitted from an AF (Application Function) to the TSCTSF.

6. In paragraph 5, A method, characterized in that the information about the UEs includes at least one of a UE identifier (ID) list, a group ID, or a DNN (Data Network Name) / S-NSSAI (Single Network Slice Selection Assistance Information).

7. In paragraph 5, A method characterized in that, through said network entity, said AMF is discovered based on coverage conditions included in a message related to said synchronization.

8. In paragraph 5, A method characterized in that the information about the above UEs includes information about all AMFs.

9. In the wireless communication system, in the TSCTSF (Time Sensitive Communication Time Synchronization Function), A transceiver capable of transmitting and receiving at least one signal; and Including a control unit coupled with the above transmitter and receiver, The above control unit: Receives messages related to synchronization from AF (Application Function), Through the network entity, at least one Access and Mobility Management Function (AMF) is discovered, transmitting a first message containing information about UEs (User equipments) to at least one AMF; and A TSCTSF characterized in that it is configured to receive a second message including information about an Area of ​​interest (AOI) based on information about the UEs from at least one AMF.

10. In paragraph 9, TSCTSF, characterized in that the information about the UEs includes at least one of a UE identifier (ID) list, a group ID, or a DNN (Data Network Name) / S-NSSAI (Single Network Slice Selection Assistance Information).

11. In paragraph 9, the control unit: A TSCTSF further characterized in that it is configured to discover at least one AMF based on a coverage condition included in a message related to said synchronization through said network entity.

12. In paragraph 9, TSCTSF characterized in that the information about the above UEs includes information about all AMFs.

13. In the AMF (Access and Mobility Management Function) in a wireless communication system, A transceiver capable of transmitting and receiving at least one signal; and Including a control unit coupled with the above transmitter and receiver, The above control unit: Receive a first message including information about UEs (User equipments) from TSCTSF (Time Sensitive Communication Time Synchronization Function), Check whether the conditions included in the information about the above UEs are satisfied, and The above TSCTSF is configured to transmit a second message including information about an Area of ​​interest (AOI) based on information about the UEs, The above AMF is discovered through network entities, AMF, characterized in that messages related to synchronization are transmitted from AF (Application Function) to the TSCTSF.

14. In paragraph 13, AMF, characterized in that the information about the UEs includes at least one of a UE identifier (ID) list, a group ID, or a DNN (Data Network Name) / S-NSSAI (Single Network Slice Selection Assistance Information).

15. In paragraph 13, the control unit: AMF characterized in that, through said network entity, said AMF is discovered based on coverage conditions included in messages related to said synchronization.

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