Communication system

Abstract

In a communication system of a structure in which a UE is capable of connecting to a plurality of networks simultaneously, a robust communication network that prevents malfunction of edge computing is provided. The communication system corresponds to a fifth generation wireless access system, and includes a plurality of networks each including a radio access network and a core network, and an edge application server connected to the networks and configured to perform edge computing, and further configured to perform switching of an edge application server with which a communication terminal communicates when the communication terminal connected to one or more of the networks and communicating with the edge application server switches a connection target network.

Description

Technical Field

[0001] This disclosure relates to wireless communication technology. This application claims priority to Japanese Patent Application No. 2024-033313, filed on March 5, 2024, the contents of which are incorporated herein by reference. Background Technology

[0002] Within the 3GPP (3rd Generation Partnership Project), the standardization organization for mobile communication systems, fifth-generation (hereinafter sometimes referred to as "5G") radio access systems were discussed as a successor to Long Term Evolution (LTE) and Long Term Evolution Advanced (LTE-A), one of the fourth-generation radio access systems (see Non-Patent Document 1) (e.g., Non-Patent Document 2). The technology for the 5G radio band is called "New Radio Access Technology" ("New Radio" is abbreviated as "NR"). NR systems are discussed based on LTE and LTE-A systems.

[0003] For example, in Europe, the organization METIS is summarizing the requirements for 5G (see Non-Patent Document 3). In 5G wireless access systems, for LTE systems, assuming a system capacity 1000 times greater, data transmission speed 100 times greater, data processing latency 1 / 5th, and simultaneous connection capacity of communication terminals 100 times greater, further reductions in power consumption and device cost can be listed as requirements (see Non-Patent Document 3).

[0004] To meet these requirements, discussions on 5G standards are ongoing within 3GPP (see Non-Patent Literature 4-23).

[0005] As an access method for NR, the downlink direction uses OFDM (Orthogonal Frequency Division Multiplexing), while the uplink direction uses OFDM and DFT-s-OFDM (Discrete Fourier Transform-spread-OFDM). Furthermore, similar to LTE and LTE-A, the 5G system does not include line switching; it uses only packet communication.

[0006] In NR, higher frequencies can be used compared to LTE to increase transmission speed and reduce processing latency.

[0007] In NR, which sometimes uses frequencies higher than LTE, a narrower beam-shaped transmit / receive range is formed (beamforming) and the direction of the beam is changed (beam scanning) so that the capability map can ensure cell coverage.

[0008] use Figure 1 To explain the decisions regarding the frame structure of the NR system in 3GPP as described in Non-Patent Document 1 (Chapter 5). Figure 1 This is an explanatory diagram showing the structure of the wireless frame used in an NR communication system. Figure 1 In NR, a radio frame is 10 ms long. The radio frame is divided into 10 equal-sized subframes. The NR frame structure supports one or more numberologies, i.e., one or more subcarrier spacings (SCS). In NR, a subframe is 1 ms long, and a time slot consists of 14 symbols, regardless of the subcarrier spacing. Furthermore, the number of time slots in a subframe is one when the subcarrier spacing is 15 kHz; the number of time slots in other subcarrier spacings increases proportionally to the subcarrier spacing (see Non-Patent Document 11 (3GPP TS38.211)).

[0009] Non-Patent Document 2 (Chapter 5) and Non-Patent Document 11 record decisions made in 3GPP related to channel structure in NR systems.

[0010] The Physical Broadcast Channel (PBCH) is a channel used for downlink transmission from a base station (hereinafter sometimes simply referred to as a "base station") to a mobile terminal device (hereinafter sometimes simply referred to as a "communication terminal" or "terminal"). The PBCH is transmitted together with the downlink synchronization signal.

[0011] In NR, the downlink synchronization signal consists of a primary synchronization signal (P-SS) and a secondary synchronization signal (S-SS). The synchronization signal is transmitted from the base station as a synchronization signal burst (hereinafter sometimes referred to as an SS burst) at a specified period for a specified duration. An SS burst consists of synchronization signal blocks (hereinafter sometimes referred to as SS blocks) for each beam of the base station.

[0012] During the duration of an SS burst, the base station changes its beam to transmit SS blocks for each beam. An SS block consists of P-SS, S-SS, and PBCH.

[0013] The Physical Downlink Control Channel (PDCCH) is the downlink transmission channel from the base station to the communication terminal. The PDCCH transmits Downlink Control Information (DCI). The DCI includes resource allocation information for the Downlink Shared Channel (DL-SCH), one of the transmission channels described later; resource allocation information for the Paging Channel (PCH), another transmission channel described later; and HARQ (Hybrid Automatic Repeat reQuest) information related to the DL-SCH. Additionally, the DCI sometimes includes Uplink Scheduling Grant. The DCI sometimes includes response signals for uplink transmissions, namely Ack (Acknowledgement) / Nack (Negative Acknowledgement). Furthermore, to allow for flexible DL / UL handover within time slots, the DCI sometimes includes Slot Format Indication (SFI). PDCCH or DCI is also known as the L1 / L2 control signal.

[0014] In NR, there are time-domain and frequency-domain regions that can serve as candidates for containing PDCCH. This region is called the Control Resource Set (CORESET). The communication terminal monitors the CORESET to acquire the PDCCH.

[0015] The Physical Downlink Shared Channel (PDSCH) is the downlink transmission channel from the base station to the communication terminal. The PDSCH maps to both the Downlink Shared Channel (DL-SCH) used as the transport channel and the PCH used as the transport channel.

[0016] The Physical Uplink Control Channel (PUCCH) is the uplink transmission channel from the communication terminal to the base station. PUCCH transmits Uplink Control Information (UCI). UCI includes response signals (Ack / Nack) for downlink transmissions, CSI (Channel State Information), and Scheduling Requests (SRs). CSI is composed of RI (Rank Indicator), PMI (Precoding Matrix Indicator), and CQI (Channel Quality Indicator) reports. RI refers to the rank information of the channel matrix in MIMO (Multiple Input Multiple Output). PMI refers to the information of the precoding matrix used in MIMO. CQI is quality information indicating the quality of received data or the quality of the communication line. UCI is sometimes transmitted via PUSCH (described later). PUCCH or UCI is also referred to as L1 / L2 control signals.

[0017] The Physical Uplink Shared Channel (PUSCH) is the uplink transmission channel from the communication terminal to the base station. The PUSCH maps to the Uplink Shared Channel (UL-SCH), which is one of the transmission channels.

[0018] The Physical Random Access Channel (PRACH) is an uplink transmission channel from a communication terminal to a base station. The PRACH transmits the random access preamble.

[0019] Downlink reference signals (RS) are symbols known in NR (Normally Injectable) communication systems. There are four types of downlink reference signals: UE-specific reference signals (DM-RS), phase tracking reference signals (PT-RS), positioning reference signals (PRS), and channel state information reference signals (CSI-RS). As physical layer measurements for communication terminals, there are measurements of the received power (RSRP) and received quality (RSRQ) of the reference signals.

[0020] The uplink reference signal is also a known symbol in NR communication systems. Three types of uplink reference signals are defined: Demodulation Reference Signal (DM-RS), Phase Tracking Reference Signal (PT-RS), and Sounding Reference Signal (SRS).

[0021] The transport channel described in Non-Patent Document 2 (Chapter 5) will be explained. The broadcast channel (BCH) in the downlink transport channel is broadcast to the entire coverage area of ​​its base station (cell). The BCH is mapped to the physical broadcast channel (PBCH).

[0022] HARQ-based retransmission control is applied to the Downlink Shared Channel (DL-SCH). The DL-SCH can broadcast to the entire coverage area of ​​the base station (cell). The DL-SCH supports dynamic or semi-static resource allocation. Semi-static resource allocation is also known as semi-persistent scheduling. To reduce the power consumption of communication terminals, the DL-SCH supports discontinuous reception (DRX). The DL-SCH is mapped to the Physical Downlink Shared Channel (PDSCH).

[0023] The Paging Channel (PCH) supports DRX (Demand Reduction) of communication terminals to reduce power consumption. The PCH is requested to broadcast over the entire coverage area of ​​the base station (cell). The PCH is mapped to physical resources such as the Physical Downlink Shared Channel (PDSCH), which can be dynamically used for traffic.

[0024] HARQ-based retransmission control is applied to the Uplink Shared Channel (UL-SCH) in the uplink transport channel. UL-SCH supports dynamic or quasi-static resource allocation. Quasi-static resource allocation is also known as Configured Grant. UL-SCH is mapped to the Physical Uplink Shared Channel (PUSCH).

[0025] The Random Access Channel (RACH) is limited to control information. RACH is subject to collision risks. RACH is mapped to the Physical Random Access Channel (PRACH).

[0026] The following explains HARQ. HARQ is a technique that improves the communication quality of a transmission line by combining Automatic Repeat Request (ARQ) and Forward Error Correction. HARQ has the following advantages: even for transmission lines where communication quality changes, retransmission can effectively enable error correction. In particular, during retransmission, the quality can be further improved by combining the initial received result with the retransmitted result.

[0027] Here's an example illustrating the retransmission method. When the receiving side cannot correctly decode the received data—in other words, when a CRC (Cyclic Redundancy Check) error occurs (CRC=NG)—a "Nack" is sent from the receiving side to the sending side. The sending side, upon receiving the "Nack," retransmits the data. When the receiving side can correctly decode the received data—in other words, when no CRC error occurs (CRC=OK)—a "ck" is sent from the receiving side to the sending side. The sending side, upon receiving the "Ack," sends the next data.

[0028] Other examples of retransmission methods are illustrated below. If a CRC error occurs at the receiving end, a retransmission request is sent from the receiving end to the sending end. The retransmission request is made via a switch of the NDI (New Data Indicator). The sending end, upon receiving the retransmission request, retransmits the data. If no CRC error occurs at the receiving end, no retransmission request is sent. If the sending end does not receive a retransmission request within a specified time, it is assumed that no CRC error occurred at the receiving end.

[0029] The logical channel described in Non-Patent Document 1 (Chapter 6) will be explained. The Broadcast Control Channel (BCCH) is a downlink channel used to broadcast system control information. The BCCH, as a logical channel, is mapped to either the broadcast channel (BCH) as a transmission channel or the downlink shared channel (DL-SCH).

[0030] The Paging Control Channel (PCCH) is a downlink channel used to transmit paging information and system information updates. The PCCH, as a logical channel, is mapped to the Paging Channel (PCH), which is used as a transport channel.

[0031] The Common Control Channel (CCCH) is a channel used to transmit control information between a communication terminal and a base station. The CCCH is used when there is no RRC connection between the communication terminal and the network. In the downlink direction, the CCCH is mapped to the Downlink Shared Channel (DL-SCH) used as a transport channel. In the uplink direction, the CCCH is mapped to the Uplink Shared Channel (UL-SCH) used as a transport channel.

[0032] The Dedicated Control Channel (DCCH) is a channel used to transmit dedicated control information between a communication terminal and the network in a one-to-one manner. The DCCH is used when there is an RRC connection between the communication terminal and the network. In the uplink, the DCCH is mapped to the Uplink Shared Channel (UL-SCH), and in the downlink, it is mapped to the Downlink Shared Channel (DL-SCH).

[0033] A Dedicated Traffic Channel (DTCH) is a channel used for sending user information and conducting one-to-one communication with the communication terminal. DTCH exists in both the uplink and downlink. In the uplink, DTCH is mapped to the Uplink Shared Channel (UL-SCH), and in the downlink, it is mapped to the Downlink Shared Channel (DL-SCH).

[0034] Location tracking of a communication terminal is performed on a unit consisting of one or more cells. Location tracking is used to locate the communication terminal even in standby mode, enabling calls to the terminal; in other words, it is performed to enable calls to the communication terminal. The area used for location tracking of this communication terminal is called the Tracking Area (TA).

[0035] In NR, calls from communication terminals within a range smaller than the tracking area are supported. This range is called the RAN Notification Area (RNA). Paging of communication terminals in the RRC_INACTIVE state, as described later, occurs within this range.

[0036] In NR, to support wider transmission bandwidths, carrier aggregation (CA) has been studied, which involves combining two or more component carriers (CCs). CA is described in Non-Patent Literature 1.

[0037] In the case of a CA (Communication Terminal), the UE, as a communication terminal, has a unique RRC (Remote Reference Cell) connection with the network (NW). Within the RRC connection, a serving cell provides NAS (Non-Access Stratum) mobility information and security input. This cell is called the Primary Cell (PCell). Depending on the UE's capabilities, secondary serving cells (SCells) are formed together with the PCell to create a group of serving cells. For a single UE, this constitutes a group of serving cells consisting of one PCell and one or more SCells.

[0038] Furthermore, 3GPP includes dual connectivity (DC), where the UE communicates with two base stations to further increase communication capacity. DC is described in non-patent documents 1 and 22.

[0039] Sometimes, one of the base stations performing dual connectivity (DC) is called the "Master Node (MN)," and the other is called the "Secondary Node (SN)." The serving cells comprised of the Master Nodes are sometimes collectively referred to as the Master Cell Group (MCG), and the serving cells comprised of the Secondary Nodes are sometimes collectively referred to as the Secondary Cell Group (SCG). In DC, the Master Cell in the MCG or SCG is called a Special Cell (SpCell or SPCell). The Special Cell in the MCG is called a PCell, and the Special Cell in the SCG is called the Primary SCG Cell (PSCell).

[0040] In addition, in NR, the base station pre-defines a portion of the carrier frequency band for the UE (hereinafter sometimes referred to as the Bandwidth Part (BWP)). The UE transmits and receives data with the base station in this BWP, thereby reducing the power consumption in the UE.

[0041] Furthermore, 3GPP has explored services (or applications) that support sidelink (SL) communication (also known as PC5 communication) in both the EPS (Evolved Packet System) and 5G core systems (described later) (see Non-Patent Documents 1, 2, 26-28). SL communication involves communication between terminals. Examples of services using SL communication include V2X (Vehicle-to-everything) and proximity services. In SL communication, in addition to direct communication between terminals, communication between the UE and the NW via a relay has also been proposed (see Non-Patent Documents 26, 28).

[0042] The physical channels used for SL (refer to Non-Patent Documents 2, 11) are described below. The Physical Sidelink Broadcast Channel (PSBCH) transmits information related to system synchronization and is sent from the UE.

[0043] The Physical Sidelink Control Channel (PSCCH) transmits control information from the UE for sidelink communication and V2X sidelink communication.

[0044] The Physical Sidelink Shared Channel (PSSCH) transmits data from the UE for sidelink communication and V2X sidelink communication.

[0045] The Physical Sidelink Feedback Channel (PSFCH) transmits HARQ feedback from the sidelink from the UE that received the PSSCH to the UE that sent the PSSCH.

[0046] The transmission channel used for SL (refer to Non-Patent Document 1) will be described. The sidelink broadcast channel (SL-BCH) has a predetermined transmission format and is mapped to the PSBCH, which is the physical channel.

[0047] The Sidelink Shared Channel (SL-SCH) supports broadcast transmission. SL-SCH supports both UE autonomous resource selection and resource allocation scheduled by the base station. While UE autonomous resource selection carries a risk of conflict, there are no conflicts when the UE allocates dedicated resources through the base station. Furthermore, SL-SCH supports dynamic link adaptation by modifying transmit power, modulation, and coding. SL-SCH is mapped to the Physical Channel Sequential Channel (PSSCH).

[0048] The logical channels used for SL (refer to Non-Patent Document 2) will be described. The Sidelink Broadcast Control Channel (SBCCH) is a sidelink channel used to broadcast sidelink system information from one UE to other UEs. The SBCCH is mapped to the SL-BCH, which serves as the transport channel.

[0049] The Sidelink Traffic Channel (STCH) is a one-to-many traffic channel used to send user information from one UE to other UEs. The STCH is used only by UEs with sidelink communication capabilities and UEs with V2X sidelink communication capabilities. One-to-one communication between two UEs with sidelink communication capabilities is also achieved through the STCH. The STCH is mapped to the SL-SCH, which serves as the transport channel.

[0050] The Sidelink Control Channel (SCCH) is a control channel used to send control information from one UE to other UEs. The SCCH is mapped to the SL-SCH, which serves as the transport channel.

[0051] In LTE, SL communication only involves broadcast. In NR, in addition to broadcast, support for unicast and groupcast has also been studied as part of SL communication (see Non-Patent Document 27 (3GPP TS23.287)).

[0052] In SL's unicast and multicast communications, it supports HARQ feedback (Ack / Nack), CSI reports, and more.

[0053] In addition, 3GPP is studying Integrated Access and Backhaul (IAB), which uses wireless methods to serve as both access links between UEs and base stations and backhaul links between base stations (see Non-Patent Literature 2, 20, 29).

[0054] For mobile communication systems, several new technologies have been proposed. For example, to improve communication capacity and reliability, a technology has been proposed that allows a single terminal to connect to multiple NWs simultaneously, thereby improving communication capacity and reliability (see Non-Patent Literature 30, 31). Furthermore, technologies that reduce latency by introducing edge computing have been proposed (see Non-Patent Literature 31, 32). Existing technical documents Non-patent literature

[0055] Non-patent document 1: 3GPP TS36.300 V18.0.0 Non-patent document 2: 3GPP TS38.300 V18.0.0 Non-patent literature 3: "Scenarios, requirements and KPIs for 5G mobile and wireless system", ICT-317669-METIS / D1.1 Non-patent literature 4: 3GPP TR23.799 V14.0.0 Non-patent literature 5: 3GPP TR38.801 V14.0.0 Non-patent document 6: 3GPP TR38.802 V14.2.0 Non-patent document 7: 3GPP TR38.804 V14.0.0 Non-patent document 8: 3GPP TR38.912 V16.0.0 Non-Patent Document 9: 3GPP RP-172115 Non-patent document 10: 3GPP TS23.501 V18.4.0 Non-patent document 11: 3GPP TS38.211 V18.1.0 Non-patent document 12: 3GPP TS38.212 V18.1.0 Non-patent document 13: 3GPP TS38.213 V18.1.0 Non-patent document 14: 3GPP TS38.214 V18.1.0 Non-patent document 15: 3GPP TS38.321 V18.0.0 Non-patent document 16: 3GPP TS38.322 V18.0.0 Non-patent document 17: 3GPP TS38.323 V18.0.0 Non-patent document 18: 3GPP TS37.324 V17.0.0 Non-patent document 19: 3GPP TS38.331 V18.0.0 Non-patent document 20: 3GPP TS38.401 V18.0.0 Non-patent document 21: 3GPP TS38.413 V18.0.0 Non-patent document 22: 3GPP TS37.340 V18.0.0 Non-patent document 23: 3GPP TS38.423 V18.0.0 Non-patent document 24: 3GPP TS38.305 V18.0.0 Non-patent document 25: 3GPP TS23.273 V18.4.0 Non-patent document 26: 3GPP TR23.703 V12.0.0 Non-patent document 27: 3GPP TS23.287 V18.2.0 Non-patent document 28: 3GPP TS23.303 V17.1.0 Non-patent document 29: 3GPP TS38.340 V18.0.0 Non-Patent Document 30: 3GPP SWS-230049 Non-patent document 31: 3GPP TS23.502 V18.4.0 Non-patent document 32: 3GPP TS23.548 V18.4.0 Summary of the Invention The technical problem that the invention aims to solve

[0056] Non-patent documents 31, 32, etc., do not disclose any actions taken when a UE is communicating with an EAS (Edge Application Server) and connecting to multiple NWs. Therefore, for example, there may be discrepancies in the identification between the UE and the communication system regarding whether there is a connection between the EAS and the UE, which could result in malfunctions of the communication system.

[0057] In view of the above-mentioned problems, one of the objectives of this disclosure is to provide a communication system that enables a UE to connect to multiple networks simultaneously and to provide a robust communication network that prevents malfunctions in edge computing. Technical means for solving technical problems

[0058] To address the aforementioned issues and achieve the objectives, the communication system disclosed herein corresponds to a fifth-generation wireless access system and includes: multiple networks, each comprising a wireless access network and a core network; and an edge application server connected to the network and used for edge computing. When a communication terminal connected to one or more networks and communicating with the edge application server switches its target network, the switching of the edge application server being communicated with by the communication terminal is also implemented. Invention Effects

[0059] According to this disclosure, in a communication system where a UE can connect to multiple networks simultaneously, a robust communication network that prevents malfunctions in edge computing can be provided.

[0060] The purpose, features, aspects, and advantages of this disclosure will become more apparent from the following detailed description and accompanying drawings. Attached Figure Description

[0061] Figure 1 This is an explanatory diagram showing the structure of a wireless frame used in an NR communication system. Figure 2 This is a block diagram showing the overall structure of a communication system 210 using the NR method discussed in 3GPP. Figure 3 This is a structural diagram of a DC based on a base station connected to the NG core. Figure 4 It is shown Figure 2 The diagram shows the structure of the mobile terminal 202. Figure 5 It is shown Figure 2 The diagram shows the structure of base station 213. Figure 6 This is a block diagram showing the structure of the 5GC section. Figure 7 This is a flowchart illustrating the process of a communication terminal (UE) in an NR-based communication system from cell search to standby mode. Figure 8 This is a diagram illustrating an example of cell structure in an NR system. Figure 9 This is a connection structure diagram illustrating an example of the connection structure of a terminal in SL communication. Figure 10 This is a connection structure diagram illustrating an example of a base station connection structure that supports integrated access and backhaul. Figure 11 This is a structural diagram illustrating an example of edge computing in a communication system where a UE is connected to multiple NWs, according to Implementation 1. Figure 12This is a structural diagram illustrating an example of EAS handover performed during NW handover of the UE in Implementation 1. Figure 13 This is a sequence diagram illustrating an example of EAS switching operation accompanying NW switching in Implementation 1. Figure 14 It is shown Figure 13 The first half of the sequence in the example of process 1130 is shown in the figure. Figure 15 It is shown Figure 13 The diagram shows the latter half of the sequence in the example of process 1130. Figure 16 It is shown Figure 13 The sequence diagram of the process 1150 is an example. Figure 17 This is a sequence diagram illustrating other examples of EAS switching operations accompanying NW switching in Implementation 1. Figure 18 This is a sequence diagram illustrating other examples of EAS switching operations accompanying NW switching in Implementation 1. Figure 19 This is a structural diagram illustrating an example of a UE remaining connected to the same EAS after NW handover in Implementation 2. Figure 20 This is a sequence diagram illustrating an example of the operation of using the switching source EAS after NW switching in Implementation 2. Figure 21 This is a sequence diagram illustrating other examples of the operation of using the switching source EAS after NW switching in Implementation 2. Figure 22 This is a structural diagram illustrating an example of a variant 1 of implementation 2 where the UE remains connected to the same local anchor point UPF and the same EAS after NW handover. Figure 23 This is a structural diagram illustrating an example of NW connection to different EAS for each diversion target in Implementation 3. Figure 24 This is a sequence diagram illustrating an example of the action of setting the EAS for the NW for each diversion target in Implementation 3. Figure 25 It is shown Figure 24 The first half of the sequence in the example of process 2230 is shown in the figure. Figure 26 It is shown Figure 24 The diagram shows the latter half of the sequence in the example of process 2230. Figure 27 This is a structural diagram illustrating an example of how the NW of a diversion target is connected to the same EAS in Implementation 4. Figure 28This is a sequence diagram illustrating an example of the operation shared by the EAS connected to each NW of the diversion target in Implementation 4. Detailed Implementation

[0062] Implementation method 1. Figure 2 This is a block diagram illustrating the overall structure of a communication system 210 using the NR method discussed in 3GPP. Figure 2 The following explanation is provided. The radio access network is referred to as NG-RAN (Next Generation Radio Access Network) 211. The communication terminal device, i.e., the mobile terminal device (hereinafter referred to as "user equipment" UE) 202, can wirelessly communicate with the base station device (hereinafter referred to as "NG-RAN NodeB" gNB) 213, and uses wireless communication to transmit and receive signals. NG-RAN 211 consists of one or more NR base stations 213.

[0063] Here, "communication terminal device" includes not only mobile terminal devices such as mobile phone terminals, but also stationary devices such as sensors. In the following description, "communication terminal device" will sometimes be abbreviated as "communication terminal".

[0064] Between UE202 and NG-RAN 211, the AS (Access Stratum) protocol is terminated. AS protocols include, for example, RRC (Radio Resource Control), SDAP (Service Data Adaptation Protocol), PDCP (Packet Data Convergence Protocol), RLC (Radio Link Control), MAC (Medium Access Control), and PHY (Physical Layer). RRC is used for the control plane (hereinafter sometimes referred to as C-plane, C-Plane, or CP), SDAP is used for the user plane (hereinafter sometimes referred to as U-plane, U-Plane, or UP), and PDCP, MAC, RLC, and PHY are used for both the C-plane and U-plane.

[0065] The Radio Resource Control (RRC) protocol between UE202 and NR base station 213 performs broadcasting, paging, and RRC connection management. The states between NR base station 213 and UE202 in RRC include RRC_IDLE, RRC_CONNECTED, and RRC_INACTIVE.

[0066] During RRC_IDLE, PLMN (Public Land Mobile Network) selection, System Information (SI) broadcasting, paging, cell re-selection, and mobility operations are performed. During RRC_CONNECTED, the mobile terminal has an RRC connection and can send and receive data with the network. Additionally, during RRC_CONNECTED, handover (HO) and neighbor cell determination (measurement) are performed. During RRC_INACTIVE, the connection between the 5G core unit 214 and the NR base station 213 is maintained while simultaneously performing System Information (SI) broadcasting, paging, cell re-selection, and mobility operations.

[0067] The gNB213 connects to the 5G core (hereinafter sometimes referred to as the "5GC unit") 214, which includes Access and Mobility Management Function (AMF), Session Management Function (SMF), or User Plane Function (UPF), via the NG interface. Control information and / or user data communication occurs between the gNB213 and the 5GC unit 214. The NG interface is a collective term for the N2 interface between the gNB213 and AMF220, the N3 interface between the gNB213 and UPF221, the N11 interface between AMF220 and SMF222, and the N4 interface between UPF221 and SMF222. One gNB213 can connect to multiple 5GC units 214. The gNBs213 are connected to each other via the Xn interface, enabling communication of control information and / or user data between them.

[0068] The 5GC unit 214 is a host device, specifically a host node, that controls the connection between the NR base station 213 and the mobile terminal (UE) 202, and allocates paging signals for one or more NR base stations (gNB) 213 and / or LTE base stations (E-UTRAN NodeB: eNB). Additionally, the 5GC unit 214 performs mobility control in the idle state. The 5GC unit 214 manages the tracking area list when the mobile terminal 202 is in the idle state, and in the inactive and active states. The 5GC unit 214 initiates the paging protocol by sending paging messages to cells belonging to the registered tracking area of ​​the mobile terminal 202.

[0069] gNB213 can form one or more cells. When one gNB213 forms multiple cells, each cell is configured to communicate with UE202.

[0070] The gNB213 can be divided into a Central Unit (CU) 215 and a Distributed Unit (DU) 216. A CU 215 constitutes one unit within the gNB213. One or more DUs 216 constitute one or more cells within the gNB213. A single DU 216 constitutes one or more cells. The CU 215 connects to the DU 216 via an F1 interface, facilitating communication of control information and / or user data between the CU 215 and DU 216. The F1 interface consists of an F1-C interface and an F1-U interface. The CU 215 handles the functions of various protocols including RRC, SDAP, and PDCP, while the DU 216 handles the functions of various protocols including RLC, MAC, and PHY. One or more Transmission Reception Points (TRPs) 219 are sometimes connected to the DU 216. The TRP 219 transmits and receives radio signals with the UE.

[0071] CU215 can be divided into CU(CU-C)217 for the C-side and CU(CU-U)218 for the U-side. CU-C217 is configured as one unit within CU215. CU-U218 is configured as one or more units within CU215. CU-C217 connects to CU-U218 via an E1 interface, facilitating control information communication between the two units. CU-C217 connects to DU216 via an F1-C interface, facilitating control information communication between the two units. CU-U218 connects to DU216 via an F1-U interface, facilitating user data communication between the two units.

[0072] 5G communication systems may include the Unified Data Management (UDM) function and Policy Control Function (PCF) described in Non-Patent Document 10 (3GPP TS23.501). UDM and / or PCF may be included in... Figure 2 In section 5GC214.

[0073] In a 5G communication system, a Location Management Function (LMF) as described in Non-Patent Document 24 (3GPP TS38.305) can be configured. As disclosed in Non-Patent Document 25 (3GPP TS23.273), the LMF can be connected to the base station via the AMF.

[0074] In 5G communication systems, non-3GPP interworking functions (N3IWF) as described in Non-Patent Document 10 (3GPP TS23.501) may also be included. N3IWF can terminate the access network (AN) between the user and the UE in non-3GPP access.

[0075] Figure 3 This is a diagram showing the structure of the DC (dual connection) connected to the NG core. Figure 3 In the diagram, solid lines represent U-Plane connections, and dashed lines represent C-Plane connections. Figure 3 In this configuration, the primary base station 240-1 can be either a gNB or an eNB. Similarly, the secondary base station 240-2 can also be either a gNB or an eNB. For example, in... Figure 3 In some contexts, the DC structure where the primary base station 240-1 is a gNB and the secondary base station 240-2 is an eNB is sometimes referred to as NG-EN-DC. Figure 3The example shown illustrates a U-Plane connection between the 5GC unit 214 and the secondary base station 240-2 via the primary base station 240-1, but it can also be established directly between the 5GC unit 214 and the secondary base station 240-2. Additionally, Figure 3 In this configuration, the core network EPC (Evolved Packet Core) connected to the LTE and LTE-A systems can replace the 5GC unit 214 and connect to the main base station 240-1. The U-Plane connection between the EPC and the secondary base station 240-2 can be directly established.

[0076] Figure 4 It is shown Figure 2 The diagram shows the structure of the mobile terminal 202. Figure 4 The transmission processing of the mobile terminal 202 shown will be described. First, control data from the control unit 310 and user data from the application unit 302 are sent to the protocol processing unit 301. Buffering of the control data and user data is possible. This buffering can be set in the control unit 310, the application unit 302, or the protocol processing unit 301. The protocol processing unit 301 performs protocol processing such as SDAP, PDCP, RLC, and MAC, for example, determining the transmission target base station in DC and assigning headers to various protocols. The protocol-processed data is transmitted to the encoding unit 304 for error correction and other encoding processing. Alternatively, data may be output directly from the protocol processing unit 301 to the modulation unit 305 without encoding processing. The data encoded by the encoding unit 304 is modulated in the modulation unit 305. Precoding for MIMO may also be performed in the modulation unit 305. After the modulated data is converted into a baseband signal, it is output to the frequency conversion unit 306 and converted into a wireless transmission frequency. Subsequently, the transmitted signal was sent from antennas 307-1 to 307-4 to base station 213. Figure 4 The example shown has four antennas, but the number of antennas is not limited to four.

[0077] Furthermore, the receiving process of the mobile terminal 202 is performed as follows: Wireless signals from the base station 213 are received via antennas 307-1 to 307-4. The received signal is converted from the wireless receiving frequency to a baseband signal by the frequency conversion unit 306, and demodulation processing is performed in the demodulation unit 308. Waiting calculations and multiplication processes can be performed in the demodulation unit 308. The demodulated data is transmitted to the decoding unit 309 for error correction and other decoding processing. The decoded data is transmitted to the protocol processing unit 301, where protocol processing such as MAC, RLC, PDCP, and SDAP is performed, including actions such as header removal in each protocol. Of the data after protocol processing, control data is transmitted to the control unit 310, and user data is transmitted to the application unit 302.

[0078] The series of processes of the mobile terminal 202 are controlled by the control unit 310. Therefore, although in Figure 4 The details have been omitted, but the control unit 310 is also connected to each of the units 302, 304 to 309.

[0079] Each part of the mobile terminal 202, such as the control unit 310, protocol processing unit 301, encoding unit 304, and decoding unit 309, is implemented, for example, by a processing circuit comprising a processor and a memory. For example, the control unit 310 is implemented by the processor executing a program describing a series of processes of the mobile terminal 202. The program describing the series of processes of the mobile terminal 202 is stored in a memory. Examples of memory are non-volatile or volatile semiconductor memories such as RAM (Random Access Memory), ROM (Read Only Memory), and flash memory. Each part of the mobile terminal 202, such as the control unit 310, protocol processing unit 301, encoding unit 304, and decoding unit 309, can be implemented by dedicated processing circuits such as FPGA (Field Programmable Gate Array), ASIC (Application Specific Integrated Circuit), and DSP (Digital Signal Processor). Figure 4 In this context, the number of antennas used for transmitting and the number of antennas used for receiving in the mobile terminal 202 may be the same or different.

[0080] Figure 5 It is shown Figure 2 The diagram shows the structure of base station 213. Figure 5 The transmission processing of the base station 213 shown will be described. The EPC communication unit 401 transmits and receives data between the base station 213 and the EPC. The 5GC communication unit 412 transmits and receives data between the base station 213 and the 5GC (5GC unit 214, etc.). The other base station communication units 402 transmit and receive data with other base stations. The EPC communication unit 401, the 5GC communication unit 412, and the other base station communication units 402 exchange information with the protocol processing unit 403. Control data from the control unit 411, and user data and control data from the EPC communication unit 401, the 5GC communication unit 412, and the other base station communication units 402 are sent to the protocol processing unit 403. Buffering of control data and user data can be performed. This buffering can be provided in the control unit 411, the EPC communication unit 401, the 5GC communication unit 412, or the other base station communication units 402.

[0081] The protocol processing unit 403 performs protocol processing for SDAP, PDCP, RLC, MAC, etc., such as routing transmitted data in DC and assigning headers to various protocols. The protocol-processed data is transmitted to the encoding unit 405 for error correction and other encoding processing. Alternatively, data may be output directly from the protocol processing unit 403 to the modulation unit 406 without encoding processing. Furthermore, data can be transmitted from the protocol processing unit 403 to other base station communication units 402. For example, in DC, data transmitted from the 5GC communication unit 412 or the EPC communication unit 401 can be transmitted to other base stations, such as auxiliary base stations, via other base station communication units 402. The encoded data undergoes modulation processing in the modulation unit 406. Precoding for MIMO can also be performed in the modulation unit 406. After the modulated data is converted into a baseband signal, it is output to the frequency conversion unit 407 and converted into a wireless transmission frequency. Then, using antennas 408-1 to 408-4, the transmission signal is transmitted to one or more mobile terminals 202. Figure 5 The example shown has four antennas, but the number of antennas is not limited to four.

[0082] Furthermore, the reception processing of base station 213 is performed as follows: Wireless signals from one or more mobile terminals 202 are received by antennas 408-1 to 408-4. The received signals are converted from the wireless receiving frequency to a baseband signal by frequency conversion unit 407, and demodulated in demodulation unit 409. The demodulated data is transmitted to decoding unit 410 for error correction and other decoding processing. The decoded data is transmitted to protocol processing unit 403, where protocol processing such as MAC, RLC, PDCP, and SDAP is performed, including actions such as header removal in each protocol. Of the data after protocol processing, control data is transmitted to control unit 411, 5GC communication unit 412, EPC communication unit 401, or other base station communication unit 402, and user data is transmitted to 5GC communication unit 412, EPC communication unit 401, or other base station communication unit 402. Data sent from other base station communication units 402 can be transmitted to 5GC communication unit 412 or EPC communication unit 401. This data could be, for example, uplink data transmitted from the DC to the 5GC communication unit 412 or the EPC communication unit 401 via other base stations.

[0083] The series of processes of base station 213 are controlled by control unit 411. Therefore, although in Figure 5 The details have been omitted, but the control unit 411 is also connected to the various units 401, 402, 405 to 410, 412.

[0084] The various parts of base station 213, such as control unit 411, protocol processing unit 403, 5GC communication unit 412, EPC communication unit 401, other base station communication unit 402, encoding unit 405, and decoding unit 410, are implemented similarly to those of mobile terminal 202 by processing circuits comprising a processor and memory, or dedicated processing circuits such as FPGA, ASIC, and DSP. Figure 5 In this system, the number of antennas used for transmitting and the number of antennas used for receiving in base station 213 can be the same or different.

[0085] As Figure 2 The example of the structure of CU215 shown, except Figure 5 In addition to the encoding unit 405, modulation unit 406, frequency conversion unit 407, antennas 408-1 to 408-4, demodulation unit 409, and decoding unit 410 shown, a structure with a DU communication unit is sometimes used. The DU communication unit is connected to the protocol processing unit 403. The protocol processing unit 403 in CU215 performs protocol processing for PDCP, SDAP, etc.

[0086] As Figure 2 The example of the structure of DU216 shown, except Figure 5 In addition to the EPC communication unit 401, other base station communication units 402, and 5GC communication unit 412 shown, a structure with a CU communication unit is sometimes used. The CU communication unit is connected to the protocol processing unit 403. The protocol processing unit 403 in DU216 performs protocol processing for PHY, MAC, RLC, etc.

[0087] Figure 6 This is a block diagram showing the structure of the 5GC section. Figure 6 The above is shown in the figure. Figure 2 The structure of the 5GC section 214 shown. Figure 6 It shows in Figure 2 The 5GC section 214 shown includes the structures of AMF, SMF, and UPF. Figure 6In the example shown, the AMF can have the functions of the control plane control unit 525, the SMF can have the functions of the session management unit 527, and the UPF can have the functions of the user plane communication unit 523 and the data network communication unit 521. The data network communication unit 521 performs data transmission and reception between the 5GC unit 214 and the data network. The base station communication unit 522 performs data transmission and reception between the 5GC unit 214 and the base station 213 via the NG interface. User data sent from the data network is transmitted from the data network communication unit 521 to the base station communication unit 522 via the user plane communication unit 523, and then sent to one or more base stations 213. User data sent from the base station 213 is transmitted from the base station communication unit 522 to the data network communication unit 521 via the user plane communication unit 523, and then sent to the data network.

[0088] Control data sent from base station 213 is transmitted from base station communication unit 522 to control plane control unit 525. Control plane control unit 525 can transmit control data to session management unit 527. Control data can be sent from data network. Control data sent from data network can be sent from data network communication unit 521 to session management unit 527 via user plane communication unit 523. Session management unit 527 can send control data to control plane control unit 525.

[0089] The user plane control unit 523 includes a PDU processing unit 523-1, a mobility anchoring unit 523-2, etc., and performs overall processing for the user plane (hereinafter sometimes referred to as U-Plane). The PDU processing unit 523-1 processes data packets, such as sending and receiving packets with the data network communication unit 521 and sending and receiving packets with the base station communication unit 522. The mobility anchoring unit 523-2 is responsible for anchoring the data path when the UE moves.

[0090] The session management unit 527 manages the PDU sessions set up between the UE and the UPF. The session management unit 527 includes a PDU session control unit 527-1 and a UE IP address allocation unit 527-2. The PDU session control unit 527-1 manages the PDU sessions between the mobile terminal 202 and the 5GC unit 214. The UE IP address allocation unit 527-2 allocates IP addresses for the mobile terminal 202.

[0091] The control plane control unit 525 includes a NAS security unit 525-1, an idle state mobility management unit 525-2, etc., and performs overall processing for the control plane (hereinafter sometimes referred to as C-Plane). The NAS security unit 525-1 performs security protection for NAS (Non-Access Stratum) messages, etc. The idle state mobility management unit 525-2 performs mobility management in standby state (idle state: RRC_IDLE state, or simply idle), generation and control of paging signals in standby state, addition, deletion, updating, retrieval of tracking areas for one or more mobile terminals 202 within the coverage area, and tracking area list management, etc.

[0092] The series of processes in the 5GC unit 214 are controlled by the control unit 526. Therefore, although in Figure 6 The details are omitted, but the control unit 526 is connected to each of the units 521-523, 525, and 527. The units of the 5GC unit 214 are similar to the control unit 310 of the mobile terminal 202 described above, and are implemented, for example, by a processing circuit comprising a processor and a memory, or by a dedicated processing circuit such as an FPGA, ASIC, or DSP.

[0093] Next, an example of a cell search method in a communication system is shown. Figure 7 This is a flowchart illustrating the process of a communication terminal (UE) in an NR-based communication system from cell search to standby mode. If the communication terminal starts cell search, in step ST601, the first synchronization signal (P-SS) and the second synchronization signal (S-SS) sent from surrounding base stations are used to achieve synchronization of time slot timing and frame timing.

[0094] P-SS and S-SS are collectively referred to as Synchronization Signal (SS). The Synchronization Signal (SS) contains a synchronization code that corresponds one-to-one with the PCI (Physical Cell Identifier) ​​assigned to each cell. In this discussion, the number of PCIs is set to 1008. The communication terminal uses these 1008 PCIs to achieve synchronization and detects (determines) the PCIs of synchronized cells.

[0095] In step ST602, the communication terminal receives the PBCH for the next cell to be synchronized. The BCCH on the PBCH maps to the MIB (Master Information Block), which contains cell structure information. Therefore, by receiving the PBCH and obtaining the BCCH, the MIB can be obtained. Information in the MIB includes, for example, the SFN (System Frame Number), scheduling information of SIB (System Information Block) 1, subcarrier spacing of SIB1, and DM-RS location information.

[0096] Additionally, the communication terminal obtains the SS block identifier via the PBCH. A portion of the bit string of the SS block identifier is contained in the MIB. The remaining bit string is contained in the identifier used to generate the DM-RS sequence accompanying the PBCH. The communication terminal uses the MIB contained in the PBCH and the DM-RS sequence accompanying the PBCH to obtain the SS block identifier.

[0097] Next, in step ST603, the communication terminal measures the received power of the SS block.

[0098] Next, in step ST604, the communication terminal selects the cell with the best reception quality from the more than one cell detected up to step ST603, for example, selecting the cell with the highest reception power, i.e., the optimal cell. Additionally, the communication terminal selects the beam with the best reception quality, for example, selecting the beam with the highest reception power in the SS block, i.e., the optimal beam. The selection of the optimal beam is, for example, using the reception power of the SS block identified by each SS block.

[0099] Next, in step ST605, the communication terminal receives the DL-SCH based on the scheduling information of SIB1 contained in the MIB, and obtains SIB1 (System Information Block) from the broadcast information BCCH. SIB1 contains information related to access to the cell, cell structure information, and scheduling information of other SIBs (SIBk: an integer k ≥ 2). In addition, SIB1 contains the Tracking Area Code (TAC).

[0100] Next, in step ST606, the communication terminal compares the TAC of SIB1 received in step ST605 with the TAC portion of the Tracking Area Identity (TAI) in the tracking area list already stored by the communication terminal. The tracking area list is also called the TAI list. TAI is identification information used to identify the tracking area, consisting of the MCC (Mobile Country Code), MNC (Mobile Network Code), and TAC (Tracking Area Code). MCC is the country code. MNC is the network code. TAC is the tracking area code number.

[0101] If the comparison result in step ST606 is the same as the TAC received in step ST605, and it is also included in the tracking area list, then the communication terminal enters standby mode in that cell. If the comparison shows that the TAC received in step ST605 is not included in the tracking area list, then the communication terminal requests a change of tracking area from the core network (EPC) containing the MME, etc., through that cell to perform a TAU (Tracking Area Update).

[0102] The apparatus constituting the core network (hereinafter sometimes referred to as "core network apparatus") updates the tracking area list based on the TAU request signal and the identification number (UE-ID, etc.) of the communication terminal sent from the communication terminal. The core network apparatus sends the updated tracking area list to the communication terminal. The communication terminal rewrites (updates) its own TAC list based on the received tracking area list. Afterward, the communication terminal enters standby mode in the cell.

[0103] Next, examples of random access methods in a communication system are shown. In random access, 4-step random access and 2-step random access are used. Furthermore, for 4-step and 2-step random access, there are conflict-based random access, which may cause timing conflicts with other mobile terminals, and conflict-free random access.

[0104] An example of a conflict-based four-step random access method is shown. As step 1, the mobile terminal sends a random access preamble to the base station. The random access preamble can be selected by the mobile terminal from a predefined range, or it can be assigned separately to the mobile terminal and notified by the base station.

[0105] As a second step, the base station sends a random access response to the mobile terminal. The random access response includes uplink scheduling information used in the third step, and the terminal identifier used in the uplink transmission in the third step.

[0106] As step 3, the mobile terminal sends an uplink transmission to the base station. The mobile terminal uses the information obtained in step 2 in this uplink transmission. As step 4, the base station notifies the mobile terminal whether a conflict has been resolved. Mobile terminals notified of no conflict end the random access process. Mobile terminals notified of a conflict restart the process from step 1.

[0107] The conflict-free 4-step random access method differs from the conflict-based 4-step random access method in the following ways: First, before step 1, the base station pre-assigns a random access preamble and uplink scheduling to the mobile terminal. Second, notification regarding conflict resolution is not required in step 4.

[0108] An example of a collision-based two-step random access method is shown. In step 1, the mobile terminal sends a random access preamble and an uplink transmission to the base station. In step 2, the base station notifies the mobile terminal of whether a collision has occurred. Mobile terminals notified of no collision end the random access process. Mobile terminals notified of a collision restart the process from step 1.

[0109] The conflict-free two-step random access method differs from the conflict-based two-step random access method in the following way: Before step 1, the base station pre-assigns a random access preamble and uplink scheduling to the mobile terminal. Additionally, in step 2, the base station sends a random access response to the mobile terminal.

[0110] Figure 8 This illustrates an example of the structure of a cell in NR. In an NR cell, a narrow beam is formed and its direction is changed for transmission. Figure 8 In the example shown, base station 750 uses beam 751-1 to transmit and receive data with the mobile terminal at certain times. At other times, base station 750 uses beam 751-2 to transmit and receive data with the mobile terminal. Similarly, base station 750 uses one or more of beams 751-3 to 751-8 to transmit and receive data with the mobile terminal. Thus, base station 750 constitutes a wide-range cell 752.

[0111] exist Figure 8 The example shown depicts a base station 750 using 8 beams, but the number of beams can also be different from 8. Additionally, in Figure 8 In the example shown, the number of beams used simultaneously by base station 750 is set to one, but it can also be multiple.

[0112] Beam identification uses the concept of QCL (Quasi-CoLocation) (refer to Non-Patent Document 14 (3GPP TS38.214)). That is, it is identified by information indicating which reference signal (e.g., SS block, CSI-RS) the beam can be considered to be identical to. This information sometimes includes the type of information about which beams can be considered to be identical, such as information about Doppler shift, Doppler shift spread, average delay, average delay spread, and spatial Rx parameters (refer to Non-Patent Document 14 (3GPP TS38.214)).

[0113] In 3GPP, sidelinks (SL) are supported for D2D (Device to Device) communication and V2V (Vehicle to Vehicle) communication (see Non-Patent Document 1 and Non-Patent Document 16). SL is defined through the PC5 interface.

[0114] In SL communication, in addition to broadcasting, support for PC5-S signaling was investigated to support unicast and groupcast (see Non-Patent Document 27 (3GPP TS23.287)). For example, PC5-S signaling was implemented to establish SL, i.e., the link used to implement PC5 communication. This link is implemented in the V2X layer and is also known as a Layer 2 link.

[0115] In addition, support for RRC signaling is being researched in SL communication (see Non-Patent Document 27 (3GPP TS23.287)). RRC signaling in SL communication is also referred to as PC5 RRC signaling. For example, the ability to notify UEs of each other during PC5 communication, and the notification of AS layer settings for using PC5 communication for V2X communication, have been proposed.

[0116] Figure 9 The diagram shows an example of the connection structure of a mobile terminal in SL communication. Figure 9 In the example shown, UE805 and UE806 exist within the coverage area 803 of base station 801. UL / DL communication 807 occurs between base station 801 and UE805. UL / DL communication 808 occurs between base station 801 and UE806. SL communication 810 occurs between UE805 and UE806. UE811 and UE812 exist outside the coverage area 803. SL communication 814 occurs between UE805 and UE811. Additionally, SL communication 816 occurs between UE811 and UE812.

[0117] As an example of communication between the UE and NW via relay in SL communication, Figure 9The UE805 shown relays the communication between UE811 and base station 801.

[0118] UEs that perform relays sometimes use with Figure 4 Same structure. Use Figure 4 The relay processing in the UE will be explained. The relay processing of UE805 in communication from UE811 to base station 801 will be explained. Radio signals from UE811 are received via antennas 307-1 to 307-4. The received signal is converted from the radio receiving frequency to a baseband signal by frequency conversion unit 306, and demodulation processing is performed in demodulation unit 308. In demodulation unit 308, waiting calculations and multiplication processes can be performed. The demodulated data is transmitted to decoding unit 309 for error correction and other decoding processing. The decoded data is transmitted to protocol processing unit 301, where protocol processing for communication with UE811, such as MAC, RLC, etc., is performed, including actions such as header removal in each protocol. Additionally, protocol processing for communication with base station 801, such as RLC, MAC, etc., is performed, including actions such as header assignment in each protocol. In the protocol processing unit 301 of UE811, PDCP and SDAP protocol processing are sometimes also performed. The data that has undergone protocol processing is transmitted to the encoding unit 304 for error correction and other encoding processing. Alternatively, data may be output directly from the protocol processing unit 301 to the modulation unit 305 without undergoing encoding processing. The data encoded by the encoding unit 304 is then modulated in the modulation unit 305. MIMO precoding may also be performed in the modulation unit 305. After the modulated data is converted into a baseband signal, it is output to the frequency conversion unit 306 and converted into a wireless transmission frequency. The transmission signal is then transmitted from antennas 307-1 to 307-4 to the base station 801.

[0119] The above content illustrates an example of UE805 relaying communication from UE811 to base station 801, but the same process is used in the relaying of communication from base station 801 to UE811.

[0120] 5G base stations can support Integrated Access and Backhaul (IAB) (see Non-Patent Documents 2, 20). An IAB-supporting base station (hereinafter sometimes referred to as an IAB base station) consists of a CU (IAB host CU) acting as an IAB host, a DU (IAB host DU) acting as an IAB host, and IAB nodes that connect to the IAB host DU and the UE via radio interfaces. An F1 interface is provided between the IAB nodes and the IAB host CU (see Non-Patent Document 2).

[0121] Figure 10The diagram illustrates an example of IAB base station connections. IAB host CU901 is connected to IAB host DU902. IAB node 903 connects to IAB host DU902 using a radio interface. IAB node 903 connects to IAB node 904 using a radio interface. That is, sometimes multiple levels of IAB node connections are made. UE905 connects to IAB node 904 using a radio interface. UE906 sometimes connects to IAB node 903 using a radio interface, and UE907 sometimes connects to IAB host DU902 using a radio interface. Multiple IAB host DU902s can connect to IAB host CU901, multiple IAB nodes 903 can connect to IAB host DU902, and multiple IAB nodes 904 can connect to IAB node 903.

[0122] In the connections between the IAB host DU and IAB nodes, and between IAB nodes, a BAP (Backhaul Adaptation Protocol) layer is set up (see Non-Patent Document 29). The BAP layer performs actions such as routing received data to the IAB host DU and / or IAB nodes, and mapping it to the RLC channel (see Non-Patent Document 29).

[0123] As an example of the structure of the IAB host CU, the same structure as CU215 is used.

[0124] As an example of the structure of the IAB host DU, it uses the same structure as DU216. In the protocol processing section of the IAB host DU, BAP layer processing is performed, such as assigning BAP headers to downlink data, routing for IAB nodes, and removing BAP headers from uplink data.

[0125] As an example of the structure of IAB nodes, sometimes in addition to Figure 5 The structure shown is excluding the EPC communication unit 401, other base station communication units 402, and 5GC communication unit 412.

[0126] use Figure 5 , Figure 10The transmit / receive processing in the IAB node will be explained. The transmit / receive processing of IAB node 903 in communication between IAB host CU901 and UE905 will be described. In uplink communication from UE905 to IAB host CU901, the radio signal from IAB node 904 is received through antenna 408 (part or all of antennas 408-1 to 408-4). The received signal is converted from the radio receiving frequency to a baseband signal by frequency conversion unit 407, and demodulation processing is performed in demodulation unit 409. The demodulated data is transmitted to decoding unit 410 for error correction and other decoding processing. The decoded data is transmitted to protocol processing unit 403, where protocol processing for communication with IAB node 904, such as MAC, RLC, etc., and actions such as header removal in each protocol, are performed. In addition, routing to the IAB host DU902 using the BAP header is performed, and protocol processing for communication with the IAB host DU902, such as assigning headers to each protocol, is carried out. The protocol-processed data is transmitted to the encoding unit 405 for error correction and other encoding processing. Alternatively, data may be output directly from the protocol processing unit 403 to the modulation unit 406 without encoding processing. The encoded data is modulated in the modulation unit 406. MIMO precoding may also be performed in the modulation unit 406. After the modulated data is converted into a baseband signal, it is output to the frequency conversion unit 407 and converted into a radio transmission frequency. Then, the transmission signal is transmitted to the IAB host DU902 using antennas 408-1 to 408-4. The same processing is performed in downlink communication from the IAB host CU901 to the UE905.

[0127] In IAB node 904, the same send and receive processing is performed as in IAB node 903. In the protocol processing unit 403 of IAB node 903, as part of the BAP layer processing, such as assigning BAP headers in uplink communication and routing to IAB node 904, and removing BAP headers in downlink communication, etc.

[0128] Edge computing can also be performed in 3GPP mobile communication systems. Edge computing can also be performed on an Edge Application Server (EAS). In edge computing, some or all of the application processing can be performed closer to the UE than the Data Network (DN). For example, the path between the UE and the anchor UPF (a UPF directly connected to the DN) can be offloaded. A local anchor UPF can also be set at this offloading target (see Non-Patent Document 32). The connection between the UE and the EAS can also be performed via this local anchor UPF.

[0129] In 3GPP mobile communication systems, a UE can connect to multiple NWs. The connection between the UE and the DN can also be made via an anchor UPF. An anchor NW (a network with an anchor UPF, hereinafter the same) can connect to one or more of these NWs connected to the UE. In this specification, an NW without an anchor UPF is referred to as a non-anchor NW. Furthermore, the device constituting an anchor NW is referred to as an anchor NW device, and the device constituting a non-anchor NW is referred to as a non-anchor NW device.

[0130] However, non-patent documents 31, 32, etc., do not disclose any operation when a UE communicating with the EAS connects to multiple NWs. Therefore, for example, there may be a discrepancy in identification between the UE and the communication system regarding whether there is a connection between the EAS and the UE, which could result in malfunctions of the communication system.

[0131] This embodiment discloses a method for solving the above-mentioned problems. Edge computing can be performed in a communication system where the UE is connected to multiple NWs. Figure 11 This is a block diagram illustrating an example of edge computing in a communication system where the UE is connected to multiple NWs. Figure 11 In the example shown, the UE is connected to NW1090 (hereinafter sometimes referred to as NW#1) and NW1091 (hereinafter sometimes referred to as NW#2), respectively. Figure 11 In the example shown, base station #1, AMF#1, UPF#1, SMF#1, SEPP (Security Edge Protection Proxy, see Non-Patent Document 10)#1, PCF#1, UDM#1, anchor UPF, NEF (Network Exposure Function)#1, and local anchor UPF#1 all belong to NW1090, which is an anchor NW. Base station #2, AMF#2, UPF#2, SMF#2, SEPP#2, PCF#2, UDM#2, and NEF#2 all belong to NW1091. The anchor UPF is connected to the DN. The path between the UE and the DN is branched from UPF#1 to local anchor UPF#1, which is connected to EAS#1. Furthermore, in the following description, the function or device belonging to the anchor NW is sometimes referred to as "anchor ○○○". For example, an AMF belonging to anchor point NW is called an anchor point AMF, and a base station belonging to anchor point NW is called an anchor point base station.

[0132] Multiple Edge Application Controllers (EAS) can be configured within an NW. For example, EASs can be configured for different applications. One or more of these EASs can be configured within a single NW, or one or more of these EASs can be configured in multiple NWs respectively. The applications corresponding to the EASs configured in each NW can be different. This, for example, improves the flexibility of edge computing.

[0133] The network controller (NW) to which the UE is connected can be switched. For example, the NW used for transmitting and receiving between the UE and the data daemon (DN) can be switched from NW#1 to NW#2, or from NW#2 to NW#1, or even to other NWs. This switching can be performed for specific services. For example, if the UE communicates with application 1 via NW#1 and with application 2 via NW#2, the path for communication related to application 2 can be switched to NW#1.

[0134] The following problem arises during this handover. Specifically, the aforementioned non-patent documents 31, 32, etc., do not disclose any NW handover actions for UEs connected to EAS. Consequently, the communication system may experience malfunctions related to edge computing.

[0135] In this embodiment, a method for solving the above-mentioned problems is disclosed. Furthermore, in the following description, the NW to which the UE is connected before the handover is sometimes referred to as the handover source NW, and the NW to which the UE is connected after the handover is sometimes referred to as the handover target NW. Additionally, the base station to which the UE is connected before the handover of the NW is sometimes referred to as the handover source base station, and the base station to which the UE is connected after the handover is sometimes referred to as the handover target base station.

[0136] In this embodiment, the connection to the EAS is re-established in the target NW during handover. The new EAS may be different from the EAS connected in the source NW during handover.

[0137] Figure 12 This is a block diagram illustrating an example of EAS handover accompanying NW handover for the UE. Figure 12 The example shown illustrates a network handover from NW#1 to NW#2 for the UE. Additionally, the EAS to which the UE connects after an EAS handover accompanying an NW handover is sometimes referred to as the target EAS. Figure 12 In the example shown, the EAS connected to the UE is switched from EAS#1 to EAS#2. The path between the UE and the DN in NW#2 is branched from UPF#2 to the local anchor point UPF#2, which is connected to EAS#2. The UE is connected to EAS#2 via UPF#2 and the local anchor point UPF#2.

[0138] The NF (Network Function) of the target NW (New Wave) can determine the EAS (Employment Assignment System) after the NW handover (hereinafter sometimes referred to as the target EAS). This NF of the target NW can be, for example, an SMF (hereinafter sometimes referred to as the target SMF), an AMF (Ampere Function), or a PCF (Programmable Component Function). This determination of the target NW's NF can be triggered by an NW handover indication from the NF of the source NW. This NF of the source NW can be, for example, an SMF (hereinafter sometimes referred to as the source SMF) or an AMF. The NF of the source NW can determine the NW handover. This NF determining the NW handover can be, for example, an SMF or an AMF.

[0139] The NF of the source NW can notify the NF of the target NW of EAS-related information. For example, this information can be included in the NW handover instruction.

[0140] This information related to the EAS may include information about the EAS's address (e.g., IP address) or information about the DN that includes the EAS (e.g., Data Network Access Identifier (see Non-Patent Document 11)). The NF (e.g., SMF) of the target NW can use this information to determine the target EAS for handover. Thus, for example, the NF of the target NW can quickly determine the target EAS for handover.

[0141] The NF of the UE and / or the target NW can perform an address search for the target EAS. For example, the address search can be performed using the method disclosed in Section 6.2.3.2.2 of Non-Patent Document 32 (3GPP TS23.548), or the method disclosed in Section 6.2.3.2.3 of that document.

[0142] Alternatively, an address search for the target EAS can be omitted. For example, if the address of the target EAS is known in the NF of the UE and / or the target NW, this search can be skipped. This allows for, for example, a rapid NW handover.

[0143] Even when the NF of the UE and / or the target NW knows the address of the target EAS, an address search for the target EAS can still be performed. Therefore, for example, it is possible to detect when a path from the UE to the target EAS is blocked, thus preventing situations where the UE cannot use the target EAS.

[0144] The UE can perform queries to the DNS (Domain Name System). For example, the UE can perform this query to the EASDF (Edge Application Server Discovery Function). This query could also be for the target EAS during handover. PDU session establishment can be performed at the target NW (Network Wireless Terminal). For example, this PDU session establishment could be for establishing a PDU session to connect the UE to the EASDF.

[0145] PDU sessions can be established or modified during the handover to the target NW. This PDU session establishment / modification can be for edge computing within the target NW. For example, it could be for establishing / modifying a PDU session used for sending and receiving data for edge computing.

[0146] A local anchor point UPF (hereinafter sometimes referred to as the handover target local anchor point UPF) can be set in the handover target NW. The handover target local anchor point UPF can be a UPF connected to the handover target EAS. The connection between the handover target local anchor point UPF and the handover target EAS can be established. The connection between the UE and the handover target EAS can be established.

[0147] It can distinguish between data exchanged between the UE and the local anchor UPF and data exchanged between the UE and the anchor UPF. This distinction can be made using PDU sessions or QoS streams.

[0148] The SMF can notify the UE of information related to this distinction. The SMF can be the SMF of the target NW or the SMF of the source NW. This notification can be made via the AMF or via the base station. For example, the notification can be made using NAS signaling or RRC signaling. Thus, for example, the UE can quickly distinguish between data directed to the EAS and data directed to the DN.

[0149] Notification of information related to this distinction can be sent from the SMF to the AMF, to the UPF, or to the base station. The UPF can be an intermediate UPF, a local anchor UPF, or an anchor UPF. Thus, for example, routing of data to EAS and data to DN can be performed within this UPF.

[0150] The NF of the target NW can notify the NF of the source NW that the EAS handover is complete. The EAS handover completion notification can be included in the NW handover completion notification. This NF can be an SMF, an AMF, or a PCF.

[0151] The notification of EAS handover completion can be triggered by an NW handover completion notification from the target NW to the source NW. As another example, the notification can be triggered by the completion of PDU session establishment in the post-handover NW, or by the completion of PDU session changes in the post-handover NW.

[0152] The UE can switch the uplink data transmission target EAS to the new EAS when the PDU session in the target NW is established and / or the change is completed.

[0153] The handover source EAS can continue to transmit downlink data to the UE. For example, even after the PDU session in the handover target NW has been established and / or changed, the UE can continue to receive the downlink data. Thus, for example, it is possible to prevent downlink data loss from the EAS to the UE.

[0154] As another example, the source EAS can forward the data exchanged between it and the UE to the target EAS. For example, this forwarding can be done via the DN. For example, this forwarding can be triggered by the release of the source NW. Thus, for example, it is possible to prevent data loss between the UE and the EAS during NW handover.

[0155] The PDU session between the UE and the source NW can be released or modified. This release / modification can be triggered by an NW handover completion notification from the target NW or by an EAS handover completion notification.

[0156] The handover source EAS can stop sending downlink data to the UE by using the release / change of its PDU session with the handover source NW as a trigger condition.

[0157] Figure 13 This is a sequence diagram illustrating an example of EAS handover action accompanying NW handover. Figure 13 In the example shown, the UE's connection target changes from NW#1, which is the anchor point NW, to NW#2, which is a non-anchor point NW. Simultaneously, the EAS to which the UE is connected changes from EAS#1 to EAS#2. Figure 13 In the example shown, NW#2 determines whether to perform the EAS switch. Figure 13 In the example shown, UPF#1, SMF#1, PCF#1, NEF#1, local anchor UPF#1 and anchor UPF belong to NW#1, and UPF#2, SMF#2, PCF#2, NEF#2, local anchor UPF#2 and UDM#2 belong to NW#2.

[0158] exist Figure 13In steps ST1101 to ST1103, data transmission and reception between the UE and EAS#1 are performed via NW#1. Steps ST1101, ST1102, and ST1103 respectively illustrate data transmission and reception between the UE and UPF#1, between UPF#1 and the local anchor UPF#1, and between the local anchor UPF#1 and EAS#1. Step ST1101 can be performed via base station #1.

[0159] exist Figure 13 In step ST1105 shown, SMF#1 detects QoS degradation. Figure 13 In the example shown, SMF#1 detects a QoS degradation related to NW#1, such as UPF#1. SMF#1 can detect this QoS degradation using QoS monitoring reports from the anchor UPF, the local anchor UPF#1, and / or UPF#1. This detection can use a QoS monitoring report from base station #1, or it can be configured and used with a QoS monitoring report from the UE.

[0160] exist Figure 13 In step ST1107 shown, SMF#1 decides to switch the NW as the data path. Figure 13 In the example shown, SMF#1 decides to switch the data path from UPF#1 to the path from UPF#2.

[0161] exist Figure 13 In steps ST1110 to ST1114, a NW handover notification is sent from SMF#1 via PCF#1 and NEF#1 to the AF (Application Function). Steps ST1110, ST1112, and ST1114 represent the notification from SMF#1 to PCF#1, from PCF#1 to NEF#1, and from NEF#1 to the AF, respectively. This notification may contain information related to the EAS, information related to the NW handover (e.g., information related to the source NW and / or the target NW), and information related to the reason for the NW handover. The AF, triggered by step ST1114, learns of the EAS handover.

[0162] exist Figure 13In step ST1120, SMF#1 instructs SMF#2 to perform a handover of the NW. This instruction can use signaling for a PDU session establishment request or signaling for a PDU session change request. The instruction may include information related to the UE, information related to the NW handover (e.g., information related to the source NW and / or the target NW), information related to the reason for the NW handover (e.g., QoS degradation), information related to the anchor point UPF, information related to the PDU session, information related to QoS flows, information related to the EAS (e.g., the EAS address and / or information related to the DN containing the EAS), and information requesting a connection between NW#2 and the EAS. For example, the information requesting a connection between NW#2 and the EAS may be included in the EAS-related information.

[0163] This indication can include QoS-related information for each path. The path can include the path between the UE and the anchor UPF, or the path between the UE and the local anchor UPF#1. Thus, for example, the target NW can quickly determine which path has a QoS problem.

[0164] This indication can include QoS-related information between each node. For example, it can include QoS-related information between the UE and the local anchor UPF, QoS-related information between the base station and the local anchor UPF, and QoS-related information between the local anchor UPF and the anchor UPF. Thus, for example, the target NW can quickly identify which nodes have QoS issues.

[0165] This instruction may include information related to the NW slice (see Non-Patent Document 10). This information may include, for example, information related to the slice type. Thus, for example, this type of NW slice can also be constructed in the target NW for handover, resulting in the ability to ensure the QoS of the NW after handover.

[0166] exist Figure 13 In procedure 1125, an EAS address search is performed in NW#2. For example, this address search can be performed using the method disclosed in section 6.2.3.2.2 of Non-Patent Document 32 (3GPP TS23.548), or the method disclosed in section 6.2.3.2.3 of that document. In procedure 1125, a PDU session establishment can be performed. For example, this PDU session establishment can be a PDU session establishment for connecting the UE to the EASDF. Figure 13 In the example shown, it is decided to use EAS#2 in NW#2. In procedure 1125, the local anchor point UPF#2 can be set.

[0167] exist Figure 13 In process 1130 shown, the connection establishment process with UPF in NW#2 is performed. The following is a description of process 1130. Figure 14 and Figure 15 It is shown Figure 13 The sequence diagram of the example process 1130. Figure 14 This represents the first half of the sequence. Figure 15 This represents the latter half of the sequence.

[0168] exist Figure 14 In step ST1201 shown, SMF#2 selects UPF. In Figure 14 In the example shown, SMF#2 selects UPF#2, deciding to use UPF#2. The selection and / or decision of the local anchor point UPF#2 can be made in step ST1201.

[0169] exist Figure 14 Step ST1203, as shown, involves establishing a session management policy association between SMF#2 and PCF#2. This process can be, for example, the process disclosed in section 4.16.4 of Non-Patent Document 31 (3GPP TS23.502). Step ST1203 can also include a process for changing the session management policy association. This process can be, for example, the process disclosed in section 4.16.5 of Non-Patent Document 31 (3GPP TS23.502).

[0170] exist Figure 14 In step ST1205, SMF#2 requests N4 session establishment from UPF#2. This request may include information regarding the distinction between data exchanged between the UE and the local anchor UPF and data exchanged between the UE and the anchor UPF. This information may include, for example, QoS-related information. For instance, it may include information related to QoS flows routed to the local anchor UPF, or information related to QoS flows routed to the anchor UPF. UPF#2 initiates N4 session establishment based on step ST1205. In step ST1207, UPF#2 responds to SMF#2 in response to step ST1205. N4 session change requests and responses may also occur in steps ST1205 and ST1207.

[0171] exist Figure 14In step ST1209, SMF#2 requests N4 session establishment from local anchor UPF#2. Local anchor UPF#2 initiates N4 session establishment based on step ST1209. A request for N4 session modification can also be made in step ST1209. Local anchor UPF#2 can initiate N4 session establishment or modify N4 session based on step ST1209. In step ST1211, local anchor UPF#2 responds to SMF#2 in response to step ST1209.

[0172] exist Figure 14 In step ST1215 shown, SMF#2 requests SMF#1 to establish the connection between the intermediate UPF and the anchor UPF. Figure 14 In the example shown, a connection establishment request can be made between UPF#2 and the anchor UPF.

[0173] exist Figure 14 In step ST1217, SMF#1 requests an N4 session change from the anchor UPF. This request may include information related to UPF#2, information related to the UE, or PDU session identification information. The anchor UPF uses the information contained in the request to establish a connection with UPF#2. In step ST1219, the anchor UPF responds to SMF#1 in response to step ST1217.

[0174] exist Figure 14 In step ST1221, SMF#1 notifies SMF#2 that the connection between the anchor UPF and the intermediate UPF has been established. This notification can be made in response to the request in step ST1215.

[0175] exist Figure 14 In steps ST1223 and ST1224, the information required for establishing a PDU session for the UE is transmitted and received between SMF#2 and AMF#2. Information required for PDU session changes can also be transmitted and received. In step ST1223, an indication for establishing a PDU session from SMF#2 to AMF#2 can be given, or an indication for PDU session changes can be given. This information can include UE-related information, PDU session-related information, QoS flow-related information, UPF-related information (e.g., UPF#2, local anchor UPF#2, and / or anchor UPF), and information related to the distinction between data oriented towards the local anchor UPF and data oriented towards the anchor UPF.

[0176] exist Figure 14In step ST226, AMF#2 notifies base station #2 of a PDU session establishment request for the UE. A PDU session change request may also be notified. This notification may include the information contained in step ST1223, or information related to the distinction between data oriented towards the local anchor UPF and data oriented towards the anchor UPF. In step ST1228, base station #2 notifies the UE of the PDU session establishment request. A PDU session change request may also be notified. RRC signaling, such as RRC establishment signaling, or RRC resetting signaling may be used in step ST1228. The notification in step ST1228 may include the information contained in step ST1226. For example, it may include information related to the distinction between data oriented towards the local anchor UPF and data oriented towards the anchor UPF. The UE can use the notification content of step ST1228 to process PDU session establishment or PDU session change.

[0177] exist Figure 15 In step ST1230, the UE responds to step ST1228 to base station #2. This response may use RRC signaling, such as RRC establishment completion signaling, or RRC resetting completion signaling. The UE may trigger step ST1230 based on the completion of PDU establishment and / or PDU change processing. In step ST1232, base station #2 responds to step ST1226 to AMF #2. This response in step ST1232 may contain N2 session management information.

[0178] exist Figure 15 In step ST1234, AMF#2 notifies SMF#2 of the N2 session management information from base station #2. This notification can be made, for example, using signaling of an Nsmf_PDUSession_UpdateSMContext request (see Non-Patent Document 31). In step ST1236, SMF#2 responds to AMF#2 in response to step ST1234. This response can use, for example, signaling of an Nsmf_PDUSession_UpdateSMContext response (see Non-Patent Document 31).

[0179] exist Figure 15 In step ST1238, SMF#2 requests an N4 session change from UPF#2. In step ST1240, UPF#2 responds to SMF#2 in response to step ST1238.

[0180] exist Figure 15In step ST1242, SMF#2 requests an N4 session change from the local anchor point UPF#2. In step ST1244, the local anchor point UPF#2 responds to SMF#2 in response to step ST1242.

[0181] exist Figure 15 The step ST1249 shown is a process for changing the session management policy association between SMF#2 and PCF#2. This process can be, for example, the process disclosed in section 4.16.5 of non-patent document 31 (3GPP TS23.502).

[0182] return Figure 13 The explanation. In Figure 13 In step ST1140, SMF#2 notifies SMF#1 that the PDU session has been established and / or the change is complete. This response can be given as a response to step ST1120.

[0183] exist Figure 13 In procedure 1150, the PDU session in NW#1 is released. Alternatively, the PDU session in NW#1 can be modified. Procedure 1150 is explained below. Figure 16 It means Figure 13 The sequence diagram of the process 1150 is an example.

[0184] exist Figure 16 In step ST1301, SMF#1 requests the release of the N4 session from the anchor UPF. It can also request an N4 session change. The anchor UPF can release the N4 session or change the N4 session, triggered by step ST1301. In step ST1303, the anchor UPF responds to SMF#1 in response to step ST1301.

[0185] exist Figure 16 In step ST1305, SMF#1 requests N4 session release from UPF#1. It can also request N4 session modification. UPF#1 can release or modify the N4 session, triggered by step ST1305. In step ST1307, UPF#1 responds to SMF#1 in response to step ST1305.

[0186] exist Figure 16 In step ST1309, SMF#1 requests the release of N4 session from the local anchor UPF#1. It can also request an N4 session change. The local anchor UPF#1 can release or change the N4 session, triggered by step ST1309. In step ST1311, the local anchor UPF responds to SMF#1 in response to step ST1309.

[0187] exist Figure 16 In steps ST1313 and ST1314, the information required for releasing the UE's PDU session is transmitted and received between SMF#1 and AMF#1. Information required for PDU session changes can also be transmitted and received. In step ST1313, an indication for releasing the PDU session from SMF#1 to AMF#1 can be given, or an indication for PDU session changes can be given. This indication can include the aforementioned information. This information can include information about the UE, information about the PDU session, information about QoS flows, and information about the UPF. This information can also include information related to EAS.

[0188] exist Figure 16 In step ST1316, AMF#1 notifies base station #1 of a PDU session release request for the UE. A PDU session change request may also be notified. This notification may include the information contained in step ST1313. In step ST1318, base station #1 notifies the UE of a PDU session release request. A PDU session change request may also be notified. RRC signaling, such as RRC release signaling, or RRC reconfiguration signaling may be used in step ST1318. The notification in step ST1318 may include the information contained in step ST1316. The UE can use the notification content in step ST1318 to process either PDU session release or PDU session change.

[0189] exist Figure 16 In step ST1320, the UE responds to base station #1 in response to step ST1318. This response may use RRC signaling, such as RRC reconfiguration completion signaling. In step ST1322, base station #1 responds to AMF #1 in response to step ST1316. This response in step ST1316 may contain N2 session management information.

[0190] exist Figure 16 In step ST1324, AMF#1 notifies SMF#1 of the N2 session management information from base station #1. This notification can be made, for example, using signaling of an Nsmf_PDUSession_UpdateSMContext request (see Non-Patent Document 31). In step ST1326, SMF#1 responds to AMF#1 in response to step ST1324. This response can use, for example, signaling of an Nsmf_PDUSession_UpdateSMContext response (see Non-Patent Document 31).

[0191] exist Figure 16The step ST1330 shown is the process of ending the session management policy association between SMF#1 and PCF#1. This process can be, for example, the process disclosed in section 4.16.6 of non-patent document 31 (3GPP TS23.502).

[0192] return Figure 13 The following is an explanation. In steps ST1151 to ST1153, data transmission and reception between the UE and EAS#2 are performed via NW#2. Steps ST1151, ST1152, and ST1153 represent data transmission and reception between the UE and UPF#2, between UPF#2 and the local anchor point UPF#2, and between the local anchor point UPF#2 and EAS#2, respectively. Step ST1151 can be performed via base station #2.

[0193] Figure 13 An example of sending a notification related to NW handover from the handover source SMF to the AF is shown, but it is also possible to omit this notification. For example, it is also possible to omit this notification. Figure 13 Steps ST1110 to ST1114 in the process. As a result, for example, it is possible to reduce the amount of processing in the switching source SMF.

[0194] As another example, the AF can notify the NF of the target NW about EAS-related information. This NF could be, for example, the target SMF. This notification from the AF to the target SMF can be made via the target NW's NEF and / or PCF. The target NW's NF can use this notification to obtain EAS-related information.

[0195] The handover source NF (e.g., SMF) may not notify the handover target NF (e.g., SMF) of information related to the handover source EAS (EAS before NW handover). For example, the NW handover indication from the handover source NF (e.g., SMF) to the handover target NF (e.g., SMF) may not include information related to the EAS. This, for example, can reduce the size of the signaling from the handover source NF to the handover target NF. The handover source NF may notify the handover target NF of a request for a connection between NW#2 and the EAS. This, for example, can enable the connection between NW#2 and the EAS, resulting in the ability to perform edge computing after NW handover.

[0196] Figure 17 This is a sequence diagram illustrating other examples of EAS handover actions accompanying NW handover. Figure 17 In the example shown, the UE's connection target changes from NW#1, which is the anchor point NW, to NW#2, which is a non-anchor point NW. Simultaneously, the EAS to which the UE is connected changes from EAS#1 to EAS#2. Figure 17 In the example shown, NW#2 determines whether to perform the EAS switch. Figure 17 In the example shown, UPF#1, SMF#1, PCF#1, NEF#1, local anchor UPF#1, and anchor UPF belong to NW#1, while base station #2, AMF#2, UPF#2, SMF#2, PCF#2, NEF#2, local anchor UPF#2, and UDM#2 belong to NW#2. Figure 17 In the middle, to and Figure 13 The same processing is labeled with the same number, and common descriptions are omitted.

[0197] Figure 17 The steps ST1101 to ST1114 shown are... Figure 13 same.

[0198] exist Figure 17 In steps ST1616 to ST1618, a NW handover notification is sent from AF to SMF#2 via NEF#2 and PCF#2. Steps ST1616, ST1617, and ST1618 represent this notification from AF to NEF#2, from NEF#2 to PCF#2, and from PCF#2 to SMF#2, respectively. Steps ST1616 to ST1618 may include information related to EAS or requirements related to latency.

[0199] exist Figure 17 In step ST1620 shown, SMF#1 instructs SMF#2 to switch to NW. Step ST1620 can be related to... Figure 13 The signaling in step ST1120 is the same as that shown. Step ST1620 may also omit information related to the EAS (e.g., the address of the EAS and / or information related to the DN containing the EAS). Thus, for example, the size of the signaling in step ST1620 can be reduced.

[0200] Figure 17 The process shown is 1125 to step ST1153 and Figure 13 same.

[0201] As an alternative solution, the EAS decision can be made by the NF of the switching source NW. This NF of the switching source can be, for example, an SMF, an AMF, or a PCF. The NF of the switching source NW can determine the EAS switch by using the decision to perform an NW switch within the current NW as a trigger condition.

[0202] The NF of the UE and / or the handover source NW can perform an address search for the handover target EAS. For example, this address search can be performed using the method disclosed in Section 6.2.3.2.2 of Non-Patent Document 32 (3GPP TS23.548), or the method disclosed in Section 6.2.3.2.3 of that document.

[0203] The UE can perform DNS queries. For example, the UE can perform this query to the EASDF. For example, this query could be a query to the target EAS. PDU session establishment can be performed in the handover source NW. For example, this PDU session establishment could be a PDU session establishment used to connect the UE to the EASDF.

[0204] The NF of the source NW can notify the NF of the target NW of EAS-related information. For example, this information can be included in the NW handover instruction. The target NF can use this information to perform either EAS handover or NW handover.

[0205] This information related to the EAS may include information about the EAS's address (e.g., IP address) or information about the DN that includes the EAS (e.g., Data Network Access Identifier (see Non-Patent Document 11)). The NF (e.g., SMF) of the target NW can use this information to initiate connection processing to the target EAS. Thus, for example, the NF of the target NW can quickly perform handover processing to the target EAS.

[0206] PDU sessions can be established or changed during the switchover of the target NW. The establishment / change of PDU sessions can be the same as the solution described above.

[0207] The NF of the target NW can notify the NF of the source NW that the EAS handover is complete. Alternatively, it can notify the NW that the handover is complete. The EAS handover completion notification can be included in the NW handover completion notification. This NF can be an SMF, an AMF, or a PCF.

[0208] The PDU session between the UE and the handover source NW can be released or modified. This release / modification can be performed using the same method as the solutions described above.

[0209] Figure 18 This is a sequence diagram illustrating other examples of EAS handover actions accompanying NW handover. Figure 18 In the example shown, the UE's connection target changes from NW#1, which is the anchor point NW, to NW#2, which is a non-anchor point NW. Simultaneously, the EAS to which the UE is connected changes from EAS#1 to EAS#2. Figure 18 In the example shown, NW#1 determines whether to perform the EAS switch. Figure 18In the example shown, UPF#1, SMF#1, PCF#1, NEF#1, local anchor UPF#1, and anchor UPF belong to NW#1, while UPF#2, SMF#2, PCF#2, NEF#2, local anchor UPF#2, and UDM#2 belong to NW#2. Figure 18 In the middle, to and Figure 13 The same processing is labeled with the same number, and common descriptions are omitted.

[0210] Figure 18 The steps ST1101 to ST1107 shown are... Figure 13 same.

[0211] exist Figure 18 In procedure 1725, an EAS address search is performed in NW#1. For example, this address search can be performed using the method disclosed in section 6.2.3.2.2 of Non-Patent Document 32 (3GPP TS23.548), or the method disclosed in section 6.2.3.2.3 of that document. In procedure 1725, a PDU session establishment can be performed. For example, this PDU session establishment can be a PDU session establishment for connecting the UE to the EASDF. Figure 18 In the example shown, it is decided to use EAS#2 in NW#2. In procedure 1725, it can be decided to set the local anchor point UPF#2.

[0212] Figure 18 The steps ST1110 to ST1114 shown are... Figure 13 same.

[0213] exist Figure 18 In step ST1720 shown, SMF#1 instructs SMF#2 to switch to NW. Step ST1720 can be related to... Figure 13 The signaling is the same as in step ST1120 shown. Step ST1720 may include information related to the local anchor UPF (e.g., information related to local anchor UPF#2). Thus, for example, a connection to local anchor UPF#2 in NW#2 can be quickly established.

[0214] Figure 18 The steps ST1130 to ST1153 shown are... Figure 13 same.

[0215] The DNS lookup can be performed by the NF of the source NW. For example, it can be performed by the source SMF. This lookup can be performed via the NF of the target NW or directly. For example, the NF of the source NW can request a lookup of the EASDF from the NF of the target NW. The NF of the target NW can then look up the address of the target EAS from the EASDF. As another example, the NF of the source NW can look up the address of the target EAS from the EASDF. The EASDF of the target NW can then look up the address of the target EAS from the DNS. The NF of the source NW can then notify the UE of the address of the target EAS. The UE can then use this notification for NW handover.

[0216] The NF (Network Function) of the target NW (Neighborhood) can notify the AF (Agency Function) of information related to the target EAS (Electronic Assignment System). This NF can be, for example, an SMF (Small and Medium Function), an AMF (Ampere Function), or a PCF (Programmable Component Function). This notification to the AF can be made via the PCF or via the NEF (Network Function).

[0217] This information related to the target EAS for handover may include information indicating that no target EAS was found, or information related to the reason for such a handover. For example, the AF may use this information as a trigger to change the latency requirements for the NW request. Thus, for example, edge computing can also be performed in the target NW for handover.

[0218] This embodiment discloses NW switching from NW#1 to NW#2, but it can also be applied to switching from NW#2 to NW#1.

[0219] According to this embodiment 1, edge computing can be performed even after NW switching, and malfunctions related to edge computing in the communication system can be prevented.

[0220] Implementation method 2. In the target NW, it is also possible to connect to the same EAS as the EAS connected in the source NW.

[0221] Figure 19 This is a block diagram illustrating an example where a UE remains connected to the same EAS after an NW handover. Figure 19 The example shown illustrates a scenario where the NW connected to the UE switches from NW#1 to NW#2. Figure 19 In the example shown, the EAS connected to the UE is still EAS#1. The path between the UE and the DN in NW#2 is branched from UPF#2 to the local anchor point UPF#2, which is connected to EAS#1. The UE is connected to EAS#1 via UPF#2 and the local anchor point UPF#2.

[0222] The normal function (NF) of the new network (NW) after the switch can determine the emergency operating system (EAS) after the NW switch. For example, the NF of the NW after the switch can determine that the EAS after the NW switch is the same as before the NW switch. The EAS determination made by the NF of the NW after the switch can be performed using the same method as disclosed in Implementation Method 1.

[0223] Figure 20 This is a sequence diagram illustrating an example of the action taken using the switching source EAS after an NW handover. Figure 20 In the example shown, the UE's connection target changes from NW#1, which is the anchor NW, to NW#2, which is a non-anchor NW. The EAS to which the UE is connected remains EAS#1. Figure 20 In the example shown, NW#2 determines whether to perform the EAS switch. Figure 20 In the example shown, base station #1, AMF#1, UPF#1, SMF#1, PCF#1, UDM#1, NEF#1, local anchor point UPF#1, and anchor point UPF belong to NW#1, while base station #2, AMF#2, UPF#2, SMF#2, PCF#2, NEF#2, local anchor point UPF#2, and UDM#2 belong to NW#2. Figure 20 In the middle, to and Figure 13 The same processing is labeled with the same number, and common descriptions are omitted.

[0224] Figure 20 Steps ST1101 to ST1120 and Figure 13 same. Figure 20 The request in step ST1120 shown may include information indicating that the EAS is the same. This information may, for example, be included in the EAS association information.

[0225] exist Figure 20 In procedure 1925, an EAS address search is performed in NW#2. For example, this address search can be performed using the method disclosed in section 6.2.3.2.2 of non-patent document 32 (3GPP TS23.548), or the method disclosed in section 6.2.3.2.3 of that document. In procedure 1925, a PDU session establishment can be performed. For example, this PDU session establishment can be a PDU session establishment for connecting the UE to the EASDF. Figure 20 In the example shown, it was decided to use EAS#1 in NW#2 as well.

[0226] Figure 20 Processes 1130 to 1150 in the middle Figure 13 same.

[0227] exist Figure 20In steps ST1151, ST1152, and ST1953, data transmission and reception between the UE and EAS#1 are performed via NW#2. Steps ST1151, ST1152, and ST1953 represent data transmission and reception between the UE and UPF#2, between UPF#2 and the local anchor UPF#2, and between the local anchor UPF#2 and EAS#1, respectively. Step ST1151 can be performed via base station #2.

[0228] The NF of the switching source NW can determine the EAS after the NW switch. For example, the NF of the switching source NW can determine that the EAS after the NW switch is the same as before the NW switch. The EAS determination made by the NF of the switching source NW can be performed using the same method as disclosed in Implementation 1.

[0229] The local anchor point UPF after a network switch can be determined in either the source network switch (NW) or the target network switch (NW). The network function (NF) of the source NW can notify the NF of the target NW of information related to the local anchor point UPF. This NF can be, for example, an SMF, an AMF, or a PCF.

[0230] Figure 21 This is a sequence diagram illustrating other examples of actions using the switching source EAS after an NW handover. Figure 21 In the example shown, the UE's connection target changes from NW#1, which is the anchor NW, to NW#2, which is a non-anchor NW. The EAS to which the UE is connected remains EAS#1. Figure 21 In the example shown, NW#1 decides not to switch EAS. Figure 21 In the example shown, base station #1, AMF#1, UPF#1, SMF#1, PCF#1, UDM#1, NEF#1, local anchor point UPF#1, and anchor point UPF belong to NW#1, while base station #2, AMF#2, UPF#2, SMF#2, PCF#2, NEF#2, local anchor point UPF#2, and UDM#2 belong to NW#2. Figure 21 In the middle, to and Figure 13 , Figure 18 , Figure 20 The same treatments are given the same labels, and common descriptions are omitted.

[0231] Figure 21 The steps ST1101 to ST1114 shown are... Figure 13 same.

[0232] exist Figure 21 The process shown in 2025 involves determining the local anchor point UPF. Figure 21 In the example shown, the local anchor point UPF#2 is chosen. For example, the local anchor point UPF#2 can be determined by SMF#2.

[0233] Figure 21 The steps shown in ST1720 and Figure 18 same.

[0234] Figure 21 Processes 1130 to 1150 shown are... Figure 13 The steps ST1151, ST1152, and ST1953 are the same. Figure 20 same.

[0235] The priority order for making the target EAS the same as or different from the source EAS (the EAS before the NW handover) can be set. For example, it is possible to prioritize making them the same. This, for example, can avoid the complexity of EAS handover processing. As another example, it is possible to prioritize making the EAS different. This, for example, can reduce latency in edge computing.

[0236] This priority order can be determined by the NF of the source NW. This NF can be, for example, an SMF, an AMF, or a PCF. As another example, the priority order can be determined by the NF of the target NW. This NF can be, for example, an SMF, an AMF, or a PCF. As another example, the priority order can be determined by the AF. The AF can notify the NF of the source NW or the NF of the target NW of this priority order. The source NF and / or the target NF can be the same as described above. The AF can notify this via the NEF or via the PCF.

[0237] This priority order can be notified within the source NW of the handover. For example, the PCF can notify the SMF or the AMF of this priority order. The same applies to the target NW of the handover. Thus, for example, the SMF can grasp this priority order.

[0238] As another example, conditions can be set to make the target EAS the same as or different from the source EAS. This condition can be determined, for example, using a threshold. This condition can include, for example, latency-related conditions. This latency can include, for example, the latency from the UE to the local anchor UPF, or it can include end-to-end latency, such as from the UE to the EAS, or it can include the latency from the local anchor UPF to the EAS, or it can include the latency from an intermediate UPF (e.g., ...). Figure 11 , Figure 12 and Figure 19 The latency from the UPF in the UE to the EAS can also include the latency from the UE to the intermediate UPF.

[0239] The NF (Functional Notification) of the source NW and / or target NW can use this condition to determine whether the target EAS (Electronic Assignment System) should be the same as or different from the source EAS. This NF can be, for example, an SMF (Self-Signaling Function), a PCF (Positioning Function), or an AMF (Ambidexterity Function). For example, the SMF of the target NW can use a delay associated with the EAS candidate that is less than or below a threshold as a trigger condition to determine that the candidate EAS is the target EAS. Alternatively, it can use a delay associated with the candidate that is greater than or above a threshold as a trigger condition to determine that the target EAS is the same as the source EAS. Thus, flexible EAS handover can be achieved, for example.

[0240] This condition can be determined by the NF of the source NW. This NF can be, for example, an SMF, an AMF, or a PCF. As another example, the condition can be determined by the NF of the target NW. This NF can be, for example, an SMF, an AMF, or a PCF. As another example, the condition can be determined by the AF. The AF can notify the NF of the source NW or the NF of the target NW of this condition. The source NF and / or the target NF can be the same as described above. The AF can notify this condition via the NEF or via the PCF.

[0241] This condition can be notified within the source NW during handover. For example, the PCF can notify the SMF or the AMF of this condition. The same applies to the target NW during handover. Thus, for example, the SMF can quickly grasp this condition.

[0242] According to this embodiment 2, network switching during edge computing can be performed quickly.

[0243] Variation 1 of Implementation 2: In the target NW, it can be connected to the same local anchor point UPF as the local anchor point UPF connected in the source NW, or it can be connected to the same EAS.

[0244] Figure 22 This is a block diagram illustrating an example where the UE remains connected to the same local anchor point (UPF) and the same EAS after a NW handover. Figure 22 The example shown illustrates a handover of the NW connected to the UE from NW#1 to NW#2. The EAS connected to the UE remains EAS#1. The path between the UE and the DN in NW#2 is branched from UPF#2 to the local anchor point UPF#1. The UE connects to EAS#1 via UPF#2 and the local anchor point UPF#1.

[0245] The NF of the source NW can notify the NF of the target NW of information related to the local anchor point UPF. For example, this information may include information related to the address of the local anchor point UPF. For example, this information may be included in the NW handover instruction notified from the source NW NF to the target NW NF.

[0246] The NF of the target NW can request a connection between its local anchor UPF and the intermediate UPF of NW#2 from the NF of the source NW. For example, this request can be made as an N4 session establishment request or an N4 session change request. The NF of the source NW can then use this notification as a trigger to establish a connection between its local anchor UPF and the intermediate UPF of NW#2.

[0247] According to this modified example 1, the utilization efficiency of NW devices, such as UPF, can be improved.

[0248] Implementation method 3. It allows for service splitting. For example, some packets of the same data service can be routed through one NW, while other packets can be routed through other NWs. Service splitting can be performed on a single PDU session or multiple PDU sessions can be established.

[0249] Edge computing can also be performed in communication systems that offload traffic. However, non-patent documents 31, 32, etc., related to edge computing do not disclose edge computing methods in the above-mentioned cases. As a result, for example, identification discrepancies may occur between the NWs of the offloaded targets, leading to malfunctions in the communication system.

[0250] In this embodiment, a method for solving the above-mentioned problems is disclosed.

[0251] EAS can be set for NW for each offloading target.

[0252] Figure 23 This is a block diagram illustrating examples of NW connections to different EAS for each shunt target. Figure 23 The example shown illustrates how the NW to which the UE is connected is split into NW#1 and NW#2. The EAS connected to the UE via NW#1 is EAS#1, and the EAS connected via NW#2 is EAS#2. EAS#1 is connected to UPF#1 via local anchor UPF#1. EAS#2 is connected to UPF#2 via local anchor UPF#2.

[0253] Figure 24 This is a sequence diagram illustrating an example of the actions of setting up the EAS for each shunt target in the NW configuration. Figure 24In the example shown, the UE's connection destination is split into NW#1 as an anchor point NW and NW#2 as a non-anchor point NW. The UE connects to EAS#1 via UPF#1 and local anchor point UPF#1, and connects to EAS#2 via UPF#2 and local anchor point UPF#2. Figure 24 In the example shown, each NW determines the EAS of the connection target. In Figure 24 In the example shown, base station #1, AMF#1, UPF#1, SMF#1, PCF#1, UDM#1, NEF#1, local anchor point UPF#1, and anchor point UPF belong to NW#1, while base station #2, AMF#2, UPF#2, SMF#2, PCF#2, NEF#2, local anchor point UPF#2, and UDM#2 belong to NW#2. Figure 24 In the middle, to and Figure 13 The same processing is labeled with the same number, and common descriptions are omitted.

[0254] exist Figure 24 In procedure 2225, an address search for the EAS in NW#1 is performed. For example, this address search can be performed using the method disclosed in section 6.2.3.2.2 of Non-Patent Document 32 (3GPP TS23.548), or the method disclosed in section 6.2.3.2.3 of that document. In procedure 2225, a PDU session establishment can be performed. For example, this PDU session establishment can be a PDU session establishment for connecting the UE to the EASDF. Figure 24 In the example shown, it is decided to use EAS#1 in NW#1. In procedure 2225, the local anchor point UPF#1 can be set.

[0255] exist Figure 24 In process 2230 shown, the connection establishment process with UPF in NW#1 is performed. The following is a description of process 2230. Figure 25 and Figure 26 It is shown Figure 24 The sequence diagram of the example of process 2230. Figure 25 This represents the first half of the sequence. Figure 26 This represents the latter half of the sequence.

[0256] exist Figure 25 In step ST2301 shown, SMF#1 selects UPF. In Figure 25 In the example shown, SMF#1 selects UPF#1, deciding to use UPF#1. The selection and / or decision of the local anchor point UPF#1 can be made in step ST2301.

[0257] exist Figure 25Step ST2303, as shown, involves establishing a session management policy association between SMF#1 and PCF#1. This process can be, for example, the process disclosed in section 4.16.4 of Non-Patent Document 31 (3GPP TS23.502). Step ST2303 can also include a process for changing the session management policy association. This process can be, for example, the process disclosed in section 4.16.5 of Non-Patent Document 31 (3GPP TS23.502).

[0258] exist Figure 25 In step ST2305, SMF#1 requests N4 session establishment from UPF#1. UPF#1 initiates N4 session establishment based on step ST2305. In step ST2307, UPF#1 responds to SMF#1 in response to step ST2305. N4 session modification requests and responses can also be made in steps ST2305 and ST2307.

[0259] exist Figure 25 In step ST2309, SMF#1 requests N4 session establishment from local anchor UPF#1. Local anchor UPF#1 initiates N4 session establishment based on step ST2309. A request for N4 session modification can also be made in step ST2309. Local anchor UPF#1 can initiate N4 session establishment or modify N4 session based on step ST2309. In step ST2311, local anchor UPF#1 responds to SMF#1 in response to step ST2309.

[0260] exist Figure 25 In step ST2317, SMF#1 requests N4 session establishment from the anchor UPF. An N4 session change request may also be made. This request may include information related to UPF#1, information related to the UE, or PDU session identification information. The anchor UPF uses the information contained in the request to establish and / or change the connection with UPF#1. In step ST2319, the anchor UPF responds to SMF#1 in response to step ST2317.

[0261] exist Figure 25In steps ST2323 and ST2324, the information required for establishing a PDU session for the UE is transmitted and received between SMF#1 and AMF#1. Information required for PDU session changes can also be transmitted and received. In step ST2323, an indication of PDU session establishment from SMF#1 to AMF#1 can be given, or an indication of PDU session change can be given. This information may include UE-related information, PDU session-related information, QoS flow-related information, and information related to UPFs (e.g., UPF#1, local anchor UPF#1, and / or anchor UPF).

[0262] exist Figure 25 In step ST2326, AMF#1 notifies base station #1 of a PDU session establishment request for the UE. A PDU session change request may also be notified. This notification may include the information contained in step ST2323. In step ST2328, base station #1 notifies the UE of the PDU session establishment request. A PDU session change request may also be notified. RRC signaling, such as RRC establishment signaling or RRC resetting signaling, may be used in step ST2328. The notification in step ST2328 may include the information contained in step ST2326. The UE can use the notification content in step ST2328 to process PDU session establishment or PDU session change.

[0263] exist Figure 26 In step ST2330 shown, the UE sends a request to base station #1. Figure 25 The response to step ST2328 is shown. This response may use RRC signaling, such as RRC establishment completion signaling, or RRC resetting completion signaling. The UE may proceed to step ST2330 triggered by the completion of PDU establishment and / or PDU change processing. In step ST2332, base station #1 communicates with AMF #1... Figure 25 The response to step ST2326 is shown. This response in step ST2326 may contain N2 session management information.

[0264] exist Figure 26 In step ST2334, AMF#1 notifies SMF#1 of the N2 session management information from base station #2. This notification can be made, for example, using signaling of an Nsmf_PDUSession_UpdateSMContext request (see Non-Patent Document 31). In step ST2336, SMF#1 responds to AMF#1 in response to step ST2334. This response can use, for example, signaling of an Nsmf_PDUSession_UpdateSMContext response (see Non-Patent Document 31).

[0265] exist Figure 26 In step ST2338, SMF#1 requests an N4 session change from UPF#1. In step ST2340, UPF#1 responds to SMF#1 in response to step ST2338.

[0266] exist Figure 26 In step ST2342, SMF#1 requests an N4 session change from the local anchor UPF#1. In step ST2344, the local anchor UPF#1 responds to SMF#1 in response to step ST2342.

[0267] exist Figure 26 In step ST2346, SMF#1 requests an N4 session change from the anchor UPF. In step ST2348, the anchor UPF responds to SMF#1 in response to step ST2346.

[0268] exist Figure 26 The step ST2349 shown is a process for changing the session management policy association between SMF#1 and PCF#1. This process can be, for example, the process disclosed in section 4.16.5 of non-patent document 31 (3GPP TS23.502).

[0269] return Figure 24 Explanation of steps ST1101 to ST1103. Figure 13 same.

[0270] exist Figure 24 In step ST2207 shown, SMF#1 decides to perform NW splitting.

[0271] exist Figure 24 In steps ST2210 to ST2214, a NW offloading notification is sent from SMF#1 to AF via PCF#1 and NEF#1. Steps ST2210, ST2212, and ST2214 represent the notification from SMF#1 to PCF#1, from PCF#1 to NEF#1, and from NEF#1 to AF, respectively. This notification may contain information related to EAS, information related to NW offloading (e.g., information related to the NW of the offloading target), and information related to the reason for NW offloading. AF, triggered by step ST2214, determines to establish EAS in the NW of the offloading target.

[0272] exist Figure 24In step ST2220, SMF#1 instructs SMF#2 on NW offloading. This instruction can use signaling for a PDU session establishment request or signaling for a PDU session change request. The instruction may include UE-related information, information related to NW offloading, information related to the reason for NW offloading (e.g., QoS degradation), information related to the PDU session, information related to QoS flows, and information related to the EAS (e.g., the EAS address and / or information related to the DN containing the EAS).

[0273] Figure 24 The process shown is 1125 to step ST1140 and Figure 13 Same. Figure 24 In the example shown, step ST1140 can be performed as a response to step ST2220.

[0274] Figure 24 Steps ST2301 to ST2303 are the same as steps ST1101 to ST1103. Steps ST1151 to ST1153 are the same as... Figure 13 same.

[0275] A party's NW can notify the AF of information related to EAS. This NW can be, for example, an SMF. This notification from the SMF to the AF can be done via the PCF and / or NEF. For example, it can be used with... Figure 17 The signaling in steps ST1110 to ST1114 is the same. The NW handover notification in this signaling can be replaced with an NW offloading notification.

[0276] The AF can notify the NF of the other party's NW of information related to EAS, as well as information related to latency requirements. This NF could be, for example, an SMF. This notification from the AF to the SMF can be done via the NEF and / or PCF. For example, it can be used with... Figure 17 The signaling in steps ST1616 to ST1618 is the same. The NW handover notification in this signaling can be replaced with an NW offloading notification.

[0277] Collaboration between EASs is possible. This collaboration can take place within the DN to which the EAS belongs.

[0278] The NF of one NW can notify the NF of another NW of information related to the EAS to which this NW is connected. This NF can be an SMF, a PCF, or an AMF. The NF of the other NW can then notify the EAS to which this NW is connected. Thus, for example, the coordination between EASs can be performed smoothly.

[0279] As another example, the NF of one party's NW can query the NF of the other party's NW regarding information related to the EAS to which the other party's NW is connected. The NF of the other party's NW can then use this query as a trigger to notify the NF of the first party's NW of the information related to the EAS to which its own NW is connected. The NF of the other party's NW can then notify the EAS to which its own NW is connected. Thus, for example, the same effect as described above can be achieved.

[0280] The NW of one of the aforementioned entities can be either an anchor point NW or a non-anchor point NW. The NW of the other entity can be either a non-anchor point NW or an anchor point NW.

[0281] As another example, coordination between EAS can be carried out via AF. Notification from NF of NW to AF and / or from AF to NF of NW can be carried out via PCF and / or NEF.

[0282] Information regarding available EAS can be communicated from the AF to one and / or both NFs. This information may include information related to latency requirements. This information may be sent in a timely manner. The NF of the NW can use this information to determine or change the EAS. For changes to the EAS, for example, EAS rediscovery can be used (see Section 6.2 of Non-Patent Document 32), or EAS reconfiguration can be used (see Section 6.3 of Non-Patent Document 32). Thus, for example, it is possible to flexibly select the EAS in a communication system.

[0283] As another solution, only one of the NWs can have an EAS, while the other NW can be without one. For example, if the latency between the UE and AF in the other NW is small, the other NW may not have an EAS. As a structure where only one NW has an EAS, for example, it can adopt a configuration similar to... Figure 11 Same structure.

[0284] The UE can route uplink data transmissions. For example, the UE can route based on the accumulated buffer size within the UE. For instance, if the buffer size exceeds or exceeds a specified threshold, the UE can send data to either of the two NWs, or simultaneously to both. If the buffer size is below or less than the specified threshold, the UE can send data to one of the NWs. Hereinafter, the NW that is the target for uplink data transmission when the buffer size is below or less than the specified threshold is sometimes referred to as the primary NW. As another example, if the buffer size exceeds or exceeds a specified threshold, the UE can send data to an NW that is not the primary NW; if the buffer size is below or less than the specified threshold, the UE can send data to the primary NW.

[0285] One of the aforementioned NWs can be either an anchor NW or a non-anchor NW. This, for example, improves flexibility in communication.

[0286] This buffer size can include the buffer size of lower layers. For example, it can include the buffer size of the SDAP layer, the buffer size of the PDCP layer, the buffer size of the RLC layer, the buffer size below the MAC layer, the buffer size of the PHY layer, or multiple buffer sizes mentioned above. Thus, for example, it is possible to perform routing that takes into account the overall buffer size of the UE.

[0287] The above routing can utilize either the buffer size for each PDU session or the buffer size for each QoS flow. This allows for flexible routing, for example, tailored to each service.

[0288] The UE's lower-level layer can notify the PDU layer of the buffer size at that lower-level layer. This lower-level layer can be SDAP, PDCP, RLC, or MAC. The buffer size can be the buffer size for each PDU session or the buffer size for each QoS flow. Thus, for example, the PDU layer can quickly ascertain the buffer size at the lower-level layer.

[0289] As another example, routing can employ QoS. This QoS can include, for example, latency or data rate. For instance, a UE can send data to a network with good QoS. Thus, for example, QoS of uplink communication can be ensured.

[0290] The UE can perform QoS monitoring. The UE can use the results of the QoS monitoring for this routing. The QoS monitored by the UE may include, for example, information related to uplink and / or downlink packet delay, information related to congestion, data rate, packet delay dispersion, information related to round-trip packet delay, and information related to uplink delay in the UE (e.g., the difference between the time when uplink data should have been sent and the time when it was actually sent).

[0291] Routing using QoS can also employ thresholds. For example, if the QoS of one NW is better than or equal to a predetermined threshold, the NW can continue to be used; if the QoS is worse than or equal to the predetermined threshold, data can be sent to other NWs. One of the aforementioned NWs can be either an anchor NW or a non-anchor NW. This ensures QoS during uplink transmission. The threshold can also have hysteresis. This, for example, prevents frequent switching of the target NW for uplink data transmission.

[0292] Routing using QoS flows can be performed on a per-QoS-flow basis. For example, a QoS flow requiring low latency can pass through a low-latency NW, while a QoS flow requiring high reliability can pass through a high-reliability NW. Thus, for example, the QoS of each QoS flow can be guaranteed.

[0293] The aforementioned threshold can be determined by the PCF. For example, it can be determined by the anchor PCF. The anchor PCF can then notify the anchor SMF of this threshold. The anchor SMF can then notify the UE of this threshold. This notification from the anchor SMF can be made via the anchor AMF or via the anchor base station.

[0294] As another example, the threshold mentioned above can be determined by the SMF. For instance, it can be determined by the anchor SMF. The anchor SMF can determine the threshold using a strategy notified from the anchor PCF. The anchor SMF can then notify the UE of the threshold. This notification from the anchor SMF to the UE can be performed in the same manner as described above.

[0295] As another example, the threshold mentioned above can be determined by the AMF, such as the anchor AMF, or by the base station, such as the anchor base station. The AMF and / or base station can then notify the UE of this threshold.

[0296] As another example, the aforementioned threshold can be determined by the NWDAF (Network Data Analytics Function). Thus, for example, the threshold can be flexibly determined based on the NW status. The NWDAF can then notify the UE of this threshold. This notification can be made via the AMF, via the base station, or directly to the UE.

[0297] As another example, information related to the EAS can be used for routing. For instance, a UE can send data to an NW that has an EAS, or it can send data to an NW that has an EAS corresponding to the application to which the data is to be sent. This can, for example, reduce latency.

[0298] As another example, information related to a set of PDUs (see Non-Patent Document 10) can be used for routing. For instance, a UE can send data from the same set of PDUs to the same NW.

[0299] One party's NW can notify the other party's NW of information related to the PDU set. For example, this notification can be included in an NW offloading instruction from one party's NW to the other party's NW.

[0300] PDU classification is possible. This classification can be performed across PDU sessions. QoS can be used for this classification. One party's NW can notify the other party's NW of information related to this classification. For example, this notification can be included in an NW offloading instruction from one party's NW to the other party's NW.

[0301] As another example related to routing, the aforementioned PDU classification can be performed. PDUs classified in the same category can be sent to the same NW. Thus, for example, even across PDU sessions, related data can be sent through the same NW, resulting in the prevention of malfunctions in the communication system.

[0302] According to this embodiment 3, identification discrepancies between NWs can be prevented, thereby preventing malfunctions in the communication system. Furthermore, an optimal EAS can be selected for each NW, resulting in, for example, reduced latency in edge computing.

[0303] Variation 1 of Implementation Method 3. When the splitting of an NW is removed and a single NW is used, the EAS used in that single NW can be applied. For example, if EAS is used in the NWs of both splitting targets, the above method can be applied; if EAS is used in the NW of one of the splitting targets, the above method can also be applied.

[0304] The EAS used in the NW on the side where the shunt was deactivated can continue to be used. For example, the method disclosed in Implementation 2 can be used. Thus, for example, it is possible to continue using the EAS used in the NW on the side where the shunt was deactivated.

[0305] Various combinations of the above methods can be used. For example, the above combinations can be used when multiple EASs are used in each of the NWs of one and / or both parties. Thus, for example, the structural flexibility of the EAS can be improved.

[0306] According to this variation 1, EAS can continue to be used even if the NW shunt is removed.

[0307] Implementation method 4. Each NW of the offloading target can be connected to the shared EAS.

[0308] Figure 27 This is a structural diagram illustrating an example of a shunt target's NW connected to the same EAS. Figure 27 The example shown illustrates how the NW to which the UE is connected is split into NW#1 and NW#2. The EAS to which the UE connects via NW#1 and the EAS to which the UE connects via NW#1 are both EAS#1. EAS#1 is connected to UPF#1 via local anchor UPF#1 and to UPF#2 via local anchor UPF#2.

[0309] The NF of one of the branching targets (e.g., NW#1, hereinafter the same) can notify the NF of the other party's NW (e.g., NW#2, hereinafter the same) of information related to the EAS connected in NW#1. NW#2 can use this notification to connect to that EAS.

[0310] Figure 28 This is a sequence diagram illustrating an example of actions shared by the EAS connected to each NW of the diversion target. Figure 28 In the example shown, the UE's connection target is split into NW#1 as an anchor point NW and NW#2 as a non-anchor point NW. The UE connects to EAS#1 via UPF#1 and local anchor point UPF#1, and connects to the same EAS#1 via UPF#2 and local anchor point UPF#2. Figure 28 In the example shown, each NW determines the EAS of the connection target. In Figure 28 In the example shown, base station #1, AMF#1, UPF#1, SMF#1, PCF#1, UDM#1, NEF#1, local anchor point UPF#1, and anchor point UPF belong to NW#1, while base station #2, AMF#2, UPF#2, SMF#2, PCF#2, NEF#2, local anchor point UPF#2, and UDM#2 belong to NW#2. Figure 28 In the middle, to and Figure 13 , Figure 24 The same treatments are given the same labels, and common descriptions are omitted.

[0311] Figure 28 The processes 2225 and 2230 shown are... Figure 24 Same as steps ST1101 to ST1103. Figure 13 Same. Steps ST2207 to ST2214 are the same. Figure 24 same.

[0312] exist Figure 28 In step ST2420, SMF#1 instructs SMF#2 to offload the NW. This instruction can use signaling for a PDU session establishment request or signaling for a PDU session change request. The instruction may include information related to the UE, information related to the NW offloading, information related to the reason for the NW offloading (e.g., QoS degradation), information related to the anchor point UPF, information related to the PDU session, information related to the QoS flow, information related to the EAS (e.g., the EAS address and / or information related to the DN containing the EAS), or information indicating the use of the same EAS as NW#1.

[0313] exist Figure 28In process 2425 shown, the local anchor point UPF is determined. Figure 28 In the example shown, it is decided to use the local anchor UPF#2 in NW#2.

[0314] Figure 28 The process shown is 1130 to step ST1140 and Figure 13 same.

[0315] Figure 28 Steps ST2301 to ST2303 are the same as steps ST1101 to ST1103. Steps ST1151 to ST1153 are the same as... Figure 13 same.

[0316] The priority order for making the EAS (Emerging Access Scale) of two NWs the same or different can be set. For example, they can be made the same, which can improve the utilization efficiency of EAS. As another example, they can be made different, which can reduce latency in edge computing.

[0317] This priority order can be determined by the NF of the anchor point NW. This NF can be, for example, an SMF, an AMF, or a PCF. As another example, this priority order can be determined by the NF of the non-anchor point NW. This NF can be, for example, an SMF, an AMF, or a PCF. As yet another example, this priority order can be determined by the AF. The AF can notify the NF of the anchor point NW, or it can notify the NF of the non-anchor point NW. The NF of the anchor point NW and / or the NF of the non-anchor point NW can be the same as described above. The AF can notify this via the NEF, or it can notify this via the PCF.

[0318] As another example, conditions can be set to make the EAS of two NWs the same or different. This condition can be determined, for example, using a threshold. This condition can include, for example, latency-related conditions. This latency can include, for example, the latency from the UE to the local anchor UPF, or the end-to-end latency, such as from the UE to the EAS, or the latency from the local anchor UPF to the EAS, or the latency from an intermediate UPF (e.g., ...). Figure 11 , Figure 12 and Figure 19 The latency from the UPF in the UE to the EAS can also include the latency from the UE to the intermediate UPF.

[0319] The NF (Functional Notification) of the anchor point NW and / or non-anchor point NW can use this condition to determine whether the target EAS (Electronic Assigned System) should be the same as or different from the source EAS. This NF can be, for example, an SMF (Self-Signaling Function), a PCF (Positioning Function), or an AMF (Ambidextrous Function). For example, the SMF of the anchor point NW can use the aforementioned delay associated with the EAS candidate being less than or below the threshold as a trigger condition to determine that the candidate EAS is the target EAS. Alternatively, it can use the aforementioned delay associated with the candidate EAS being greater than or above the threshold as a trigger condition to determine that the target EAS is the same as the source EAS. Thus, for example, flexible EAS handover can be achieved.

[0320] This condition can be determined by the NF of the anchor point NW. This NF can be, for example, an SMF, an AMF, or a PCF. As another example, the condition can be determined by the NF of a non-anchor point NW. This NF can be, for example, an SMF, an AMF, or a PCF. As yet another example, the condition can be determined by the AF. The AF can notify the NF of the anchor point NW or the NF of a non-anchor point NW of the condition. The NF of the anchor point NW and / or the NF of the non-anchor point NW can be the same as described above. The AF can notify the condition via the NEF or via the PCF.

[0321] Uplink data from the UE can be routed. This routing can be performed, for example, using the same method disclosed in Implementation 3.

[0322] The EAS can determine the conditions used for the routing (e.g., the threshold disclosed in Implementation 3). The EAS can then notify the UE of these conditions. Thus, for example, flexible routing can be achieved.

[0323] According to this embodiment 4, for example, the utilization efficiency of EAS can be improved.

[0324] Variation 1 of Implementation Method 4. In NW splitting, both NWs can be connected to the same local anchor point (UPF) or the same EAS. The connection structure can be, for example, with... Figure 22 The structures shown are the same.

[0325] The NF of one NW (e.g., NW#1) can notify the NF of the other NW (e.g., NW#2) of information related to the local anchor UPF. For example, this information may include information about the address of the local anchor UPF. This information may be included, for example, in an instruction for NW offloading from NW#1 to NW#2.

[0326] The NF of NW#2 can request a connection between its local anchor UPF and the intermediate UPF of NW#2 from the NF of NW#1. For example, this request can be made as an N4 session establishment request or as an N4 session change request. The NF of NW#1 can use this notification as a trigger to establish a connection between its local anchor UPF and the intermediate UPF of NW#2.

[0327] According to this modified example 1, the utilization efficiency of NW devices, such as UPF, can be improved.

[0328] Implementation Method 5. EAS relocation can be performed. For example, EAS relocation can be performed in the event of QoS degradation between the local anchor point UPF and the UE connected to the EAS.

[0329] The reconfiguration of EAS can be determined by the NF of NW or by the AMF. The NF can be SMF, AMF, or PCF.

[0330] Even when the UE is connected to multiple NWs, EAS reconfiguration is possible. However, non-patent documents 31, 32, etc., related to edge computing, do not disclose the actions taken when one NW decides to reconfigure the EAS when the same EAS is used in multiple NWs. Therefore, for example, identification discrepancies related to the EAS may arise in the two NWs, potentially leading to malfunctions in the communication system.

[0331] In this embodiment, a method for solving the above-mentioned problems is disclosed.

[0332] In the communication system of this embodiment, the EAS is reconfigured in both NWs. The target EAS for reconfiguration can be shared by both NWs. The reconfiguration of the EAS can be determined by the NF of one NW. This NF can be SMF, AMF, or PCF.

[0333] The NF can notify the NF of the other party's NW of information related to the reconfiguration of the EAS. The NF of the other party's NW can be an SMF, an AMF, or a PCF. The information related to the reconfiguration of the EAS can include information related to the address of the EAS (e.g., IP address) or information related to the DN that includes the EAS (e.g., Data Network Access Identifier (see Non-Patent Document 11)). The NF of the other party's NW can use this notification as a trigger to reconfigure the EAS of the other party's NW.

[0334] As another example, the EAS of the reconfiguration target can be different in the NWs of the two parties. The NF of the other party's NW can be reconfigured to an EAS different from that of the NW of the first party, triggered by the aforementioned notification.

[0335] The priority order for reconfiguring the target EAS can be set to be the same or different. For example, it is possible to prioritize making them the same. This, for example, avoids the complexity of EAS switching processes. As another example, it is possible to prioritize making the EAS different. This, for example, reduces latency in edge computing.

[0336] This priority order can be determined by the NF of the anchor point NW. This NF can be, for example, an SMF, an AMF, or a PCF. As another example, this priority order can be determined by the NF of the non-anchor point NW. This NF can be, for example, an SMF, an AMF, or a PCF. As yet another example, this priority order can be determined by the AF. The AF can notify the NF of the anchor point NW or the NF of the non-anchor point NW of this priority order. The NFs of the anchor point NW and / or the non-anchor point NW can be the same as described above. The AF can notify this order via the NEF or via the PCF.

[0337] As another example, conditions can be set to make the EAS of the reconfiguration target the same or different. This condition can be determined, for example, using a threshold. This condition can be, for example, the same as the condition disclosed in Implementation 2.

[0338] The NF (Functional Function) of the anchor point NW and / or non-anchor point NW can use this condition to determine whether to make the EAS of the reconfigured target the same or different. This NF can be, for example, an SMF (Signal-Signal Function), a PCF (Personalized Function), or an AMF (Ambience-Signal Function). For example, the SMF of the anchor point NW can use the aforementioned latency related to the EAS of the reconfigured target being less than or below the threshold as a trigger condition to make the reconfigured target EAS the same; as another example, it can use the aforementioned latency related to the EAS of the reconfigured target being greater than or above the threshold as a trigger condition to make the reconfigured target EAS different. Thus, for example, flexible EAS switching can be achieved.

[0339] This condition can be determined by the NF of the anchor point NW. This NF can be, for example, an SMF, an AMF, or a PCF. As another example, the condition can be determined by the NF of a non-anchor point NW. This NF can be, for example, an SMF, an AMF, or a PCF. As yet another example, the condition can be determined by the AF. The AF can notify the NF of the anchor point NW or the NF of a non-anchor point NW of the condition. The NF of the anchor point NW and / or the NF of the non-anchor point NW can be the same as described above. The AF can notify the condition via the NEF or via the PCF.

[0340] Other solutions are disclosed. Only one party's NW performs EAS reconfiguration. One party's NW notifies the other party's NW of information related to the EAS reconfiguration. This information may include information related to the EAS address (e.g., IP address) or information related to the DN that includes the EAS (e.g., Data Network Access Identifier (see Non-Patent Document 11)).

[0341] Information related to EAS reconfiguration can be communicated from the NF of one party's NW to the NF of the other party's NW, or via the AF. This information may include, for example, the reason for reconfiguration (e.g., UE mobility, QoS degradation). The NF and / or AF of the other party's NW can use this information to obtain information related to EAS reconfiguration.

[0342] According to this embodiment 5, it is possible to prevent discrepancies in the identification of EAS in the NW of both parties, and as a result, it is possible to prevent malfunctions in the communication system.

[0343] Transmission and reception between the base station and CN nodes (excluding the AMF) can be performed via the AMF. Alternatively, transmission and reception between the base station and CN nodes (excluding the AMF) can be performed without using the AMF. By bypassing the AMF, signaling traffic can be reduced, and the load on the AMF can be decreased.

[0344] In this specification, a node can be a function.

[0345] In the communication system disclosed herein, one gNB constitutes one or more cells. In this disclosure, it is referred to as gNB or cell, but unless otherwise specified, it can be either gNB or cell.

[0346] In this disclosure, gNB can be either MCG or SCG.

[0347] The above embodiments and their modifications are merely illustrative, and the embodiments and their modifications can be freely combined. Furthermore, any structural elements of the embodiments and their modifications can be appropriately modified or omitted.

[0348] For example, in the above embodiments and their variations, a time slot is an example of a time unit for communication in a fifth-generation communication system. A time slot can be a scheduling unit. In the above embodiments and their variations, processing can be performed by recording in time slot units, such as TTI units, subframe units, sub-time slot units, and micro-time slot units.

[0349] For example, the methods disclosed in the above embodiments and their variations can be applied to IABs. They can be applied to communication between the IAB host and IAB nodes. They can also be applied to the processing of Uu within an IAB.

[0350] The various methods disclosed herein are summarized and recorded below as appendices.

[0351] (Note 1) A communication system, This communication system corresponds to a fifth-generation wireless access system, and is characterized by including: Multiple networks, which respectively include a radio access network and a core network; and An edge application server, which is connected to the network and used for edge computing, When a communication terminal connected to one or more networks and communicating with the edge application server switches its connection target network, the edge application server being communicated with by the communication terminal is also switched. (Note 2) The communication system as described in Note 1 is characterized in that, The network device constituting the target network determines the edge application server that the communication terminal connects to after switching the target network. (Note 3) The communication system as described in Note 1 is characterized in that, The network device constituting the switching source determines the edge application server that the communication terminal connects to after switching the target network. (Appendix 4) A communication system, This communication system corresponds to a fifth-generation wireless access system, and is characterized by including: Multiple networks, which respectively include a radio access network and a core network; and An edge application server, which is connected to the network and used for edge computing, When a communication terminal connected to one or more networks and communicating with the edge application server switches the target network, the edge application server that the communication terminal is communicating with is not switched, but the communication path between the communication terminal and the edge application server is switched to a path via the network of the target network. (Note 5) The communication system as described in any one of Notes 1 to 4 is characterized in that, When the communication terminal is simultaneously connected to multiple networks and traffic is distributed to each connected network, a data transmission path is established between the communication terminal and multiple edge application servers that are different for each connected network. (Note 6) The communication system as described in any one of Notes 1 to 4 is characterized in that, When the communication terminal is simultaneously connected to multiple networks and traffic is diverted to each connected network, a data transmission path is established between the communication terminal and the shared edge application server via each network connected to the communication terminal. (Note 7) The communication system as described in any one of Notes 1 to 6 is characterized in that, When the specified conditions are met, the edge application server to which the communication terminal is connected is reconfigured. Label Explanation

[0352] 202 Communication terminal device (mobile terminal) 210 Communication System 213, 240-1, 240-2, 750 Base Station Equipment (NR Base Station, Base Station) 214 5G Core Unit 215 Central Unit 216 Distributed Units 217 Control plane central unit 218 User-facing Central Unit 219 TRP 301 and 403 Protocol Processing Department 302 Application Department 304 and 405 coding sections Modulation sections 305 and 406 306, 407 Frequency Conversion Section Antennas 307-1 to 307-4 and 408-1 to 408-4 308, 409 De-escalation Department Decoding sections 309 and 410 Control Departments 310, 411, and 526 401 EPC Communications Department 402 Other Base Station Communications Department 412 5GC Communications Department 521 Data Network Communications Department 522 Base Station Communications Department 523 User Plane Communications Department 523-1 PDU Processing Department 523-2 Moving Anchoring Unit 525 Control Panel Control Unit 525-1 NAS Security Department 525-2 Idle Status Mobility Management Department 527 Session Management Department 527-1 PDU Session Control Unit 527-2 UE IP Address Allocation Department 751-1~751-8 Beams 752 Community.

Claims

1. A communication system, This communication system corresponds to a fifth-generation wireless access system, characterized in that, include: Multiple networks, which include a wireless access network and a core network; as well as An edge application server, which is connected to the network and used for edge computing, When a communication terminal connected to one or more networks and communicating with the edge application server switches its connection target network, the edge application server being communicated with by the communication terminal is also switched.

2. The communication system as described in claim 1, characterized in that, The network device constituting the target network determines the edge application server that the communication terminal connects to after switching the target network.

3. The communication system as described in claim 1, characterized in that, The network device constituting the switching source determines the edge application server that the communication terminal connects to after switching the target network.

4. A communication system, This communication system corresponds to a fifth-generation wireless access system, characterized in that, include: Multiple networks, which include a wireless access network and a core network; as well as An edge application server, which is connected to the network and used for edge computing, When a communication terminal connected to one or more networks and communicating with the edge application server switches the target network, the edge application server that the communication terminal is communicating with is not switched, but the communication path between the communication terminal and the edge application server is switched to a path via the network of the target network.

5. The communication system as described in any one of claims 1 to 4, characterized in that, When the communication terminal is simultaneously connected to multiple networks and traffic is distributed to each connected network, a data transmission path is established between the communication terminal and multiple edge application servers that are different for each connected network.

6. The communication system as described in any one of claims 1 to 4, characterized in that, When the communication terminal is simultaneously connected to multiple networks and traffic is diverted to each connected network, a data transmission path is established between the communication terminal and the shared edge application server via each network connected to the communication terminal.

7. The communication system as described in claim 1, characterized in that, When the specified conditions are met, the edge application server to which the communication terminal is connected is reconfigured.

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