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WO2025146774A1 - Système de communication - Google Patents

Système de communication Download PDF

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Publication number
WO2025146774A1
WO2025146774A1 PCT/JP2024/044750 JP2024044750W WO2025146774A1 WO 2025146774 A1 WO2025146774 A1 WO 2025146774A1 JP 2024044750 W JP2024044750 W JP 2024044750W WO 2025146774 A1 WO2025146774 A1 WO 2025146774A1
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WIPO (PCT)
Prior art keywords
network
anchor
base station
data
communication
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English (en)
Japanese (ja)
Inventor
忠宏 下田
満 望月
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Mitsubishi Electric Corp
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Mitsubishi Electric Corp
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W24/00—Supervisory, monitoring or testing arrangements
    • H04W24/04—Arrangements for maintaining operational condition
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/08—Reselecting an access point
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/12—Reselecting a serving backbone network switching or routing node
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/16—Performing reselection for specific purposes
    • H04W36/18—Performing reselection for specific purposes for allowing seamless reselection, e.g. soft reselection
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W76/00—Connection management
    • H04W76/10—Connection setup
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W76/00—Connection management
    • H04W76/30—Connection release
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
    • H04W88/14—Backbone network devices

Definitions

  • This disclosure relates to wireless communication technology.
  • 5G fifth-generation
  • LTE Long Term Evolution
  • LTE-A Long Term Evolution Advanced
  • NR New Radio Access Technology
  • the NR system is being considered based on the LTE system and the LTE-A system.
  • Non-Patent Document 3 For example, in Europe, an organization called METIS has compiled 5G requirements (see Non-Patent Document 3).
  • the requirements for a 5G wireless access system are that it will have 1,000 times the system capacity, 100 times the data transmission speed, one-fifth (1/5) the data processing delay, and 100 times the number of simultaneous connections of communication terminals compared to an LTE system, while also achieving further reductions in power consumption and lower costs for the equipment (see Non-Patent Document 3).
  • NR's access method will be OFDM (Orthogonal Frequency Division Multiplexing) in the downlink direction, and OFDM and DFT-s-OFDM (Discrete Fourier Transform-spread-OFDM) in the uplink direction. Also, like LTE and LTE-A, the 5G system will not include circuit switching and will only use packet communication methods.
  • OFDM Orthogonal Frequency Division Multiplexing
  • DFT-s-OFDM Discrete Fourier Transform-spread-OFDM
  • NR is capable of using higher frequencies than LTE in order to improve transmission speeds and reduce processing delays.
  • NR which may use higher frequencies than LTE, ensures cell coverage by forming a narrow beam-shaped transmission and reception range (beamforming) and changing the direction of the beam (beam sweeping).
  • Figure 1 is an explanatory diagram showing the configuration of a radio frame used in an NR communication system.
  • one radio frame is 10 ms.
  • the radio frame is divided into 10 equally sized subframes.
  • one or more numerologies i.e., one or more subcarrier spacings (SCS)
  • SCS subcarrier spacings
  • one subframe is 1 ms regardless of the subcarrier spacing, and one slot is composed of 14 symbols.
  • Non-Patent Document 2 (Chapter 5) and Non-Patent Document 11.
  • the Physical Broadcast Channel is a channel for downlink transmission from a base station device (hereinafter sometimes simply referred to as a "base station”) to a communication terminal device (hereinafter sometimes referred to as a “communication terminal” or “terminal”) such as a mobile terminal device (hereinafter sometimes simply referred to as a “mobile terminal”).
  • the PBCH is transmitted together with a downlink synchronization signal.
  • Downstream synchronization signals in NR include a primary synchronization signal (P-SS) and a secondary synchronization signal (S-SS).
  • Synchronization signals are transmitted from base stations as synchronization signal bursts (hereinafter sometimes referred to as SS bursts) at a specified cycle and for a specified duration.
  • SS bursts are composed of synchronization signal blocks (hereinafter sometimes referred to as SS blocks) for each beam of the base station.
  • the base station transmits the SS blocks of each beam by changing the beam during the duration of the SS burst.
  • the SS block is composed of P-SS, S-SS, and PBCH.
  • the Physical Downlink Control Channel is a channel for downlink transmission from a base station to a communication terminal.
  • the PDCCH carries downlink control information (DCI).
  • the DCI includes resource allocation information for the Downlink Shared Channel (DL-SCH), which is one of the transport channels described below, resource allocation information for the Paging Channel (PCH), which is one of the transport channels described below, and HARQ (Hybrid Automatic Repeat reQuest) information for the DL-SCH.
  • the DCI may also include an uplink scheduling grant.
  • the DCI may also include an Ack (Acknowledgement)/Nack (Negative Acknowledgement), which is a response signal to the uplink transmission.
  • the DCI may include a slot format indication (SFI).
  • SFI slot format indication
  • the PDCCH or DCI is also called an L1/L2 control signal.
  • a time-frequency region is provided that is a candidate for including PDCCH. This region is called the control resource set (CORESET).
  • the communication terminal monitors the CORESET and acquires the PDCCH.
  • the Physical Downlink Shared Channel is a channel for downlink transmission from a base station to a communication terminal.
  • the PDSCH is mapped to the Downlink Shared Channel (DL-SCH), which is a transport channel, and the PCH, which is a transport channel.
  • DL-SCH Downlink Shared Channel
  • PCH which is a transport channel
  • the Physical Uplink Control Channel is a channel for uplink transmission from a communication terminal to a base station.
  • the PUCCH carries uplink control information (UCI).
  • the UCI includes Ack/Nack, which is a response signal for downlink transmission, CSI (Channel State Information), and Scheduling Request (SR).
  • CSI is composed of RI (Rank Indicator), PMI (Precoding Matrix Indicator), and CQI (Channel Quality Indicator) reports.
  • RI is rank information of the channel matrix in MIMO (Multiple Input Multiple Output).
  • PMI is information of the precoding weight matrix used in MIMO.
  • CQI is quality information that indicates the quality of received data or the quality of the communication path.
  • UCI may be carried by the PUSCH, which will be described later.
  • PUCCH or UCI is also called an L1/L2 control signal.
  • the Physical Uplink Shared Channel (PUSCH) is a channel for uplink transmission from a communication terminal to a base station.
  • the Uplink Shared Channel (UL-SCH) which is one of the transport channels, is mapped to the PUSCH.
  • the Physical Random Access Channel is a channel for uplink transmission from a communication terminal to a base station.
  • the PRACH carries a random access preamble.
  • the downlink reference signal is a known symbol in an NR communication system.
  • the following four types of downlink reference signals are defined: UE-specific reference signals, namely Demodulation Reference Signal (DM-RS), Phase Tracking Reference Signal (PT-RS), Positioning Reference Signal (PRS), and Channel State Information Reference Signal (CSI-RS).
  • Measurements of the physical layer of a communication terminal include reference signal received power (RSRP) and reference signal received quality (RSRQ).
  • RSRP reference signal received power
  • RSRQ reference signal received quality
  • the uplink reference signal is a known symbol in an NR communication system.
  • Three types of uplink reference signals are defined: Data demodulation reference signal (DM-RS), phase tracking reference signal (PT-RS), and sounding reference signal (SRS).
  • DM-RS Data demodulation reference signal
  • PT-RS phase tracking reference signal
  • SRS sounding reference signal
  • Non-Patent Document 2 The following describes the transport channels described in Non-Patent Document 2 (Chapter 5).
  • the broadcast channel (BCH) is broadcast to the entire coverage of the base station (cell).
  • the BCH is mapped to the physical broadcast channel (PBCH).
  • PBCH physical broadcast channel
  • HARQ retransmission control is applied to the downlink shared channel (DL-SCH).
  • DL-SCH can be notified to the entire coverage of the base station (cell).
  • DL-SCH supports dynamic or semi-static resource allocation. Semi-static resource allocation is also called semi-persistent scheduling.
  • DL-SCH supports discontinuous reception (DRX) of communication terminals to reduce power consumption of communication terminals.
  • DL-SCH is mapped to the physical downlink shared channel (PDSCH).
  • the Paging Channel supports DRX in communication terminals to enable low power consumption in the communication terminals.
  • the PCH is required to notify the entire coverage of the base station (cell).
  • the PCH is dynamically mapped to physical resources such as the Physical Downlink Shared Channel (PDSCH) that can be used for traffic.
  • PDSCH Physical Downlink Shared Channel
  • the uplink shared channel (UL-SCH) is subject to retransmission control using HARQ.
  • the UL-SCH supports dynamic or semi-static resource allocation. Semi-static resource allocation is also called configured grant.
  • the UL-SCH is mapped to the physical uplink shared channel (PUSCH).
  • the Random Access Channel is limited to control information. There is a risk of collisions on the RACH.
  • the RACH is mapped to the Physical Random Access Channel (PRACH).
  • PRACH Physical Random Access Channel
  • HARQ is a technology that improves the communication quality of a transmission path by combining Automatic Repeat reQuest (ARQ) and Forward Error Correction.
  • ARQ Automatic Repeat reQuest
  • HARQ has the advantage that error correction works effectively by retransmission even for transmission paths where the communication quality changes. In particular, it is possible to obtain further quality improvement by combining the reception results of the initial transmission and the retransmission when retransmitting.
  • a CRC error occurs on the receiving side
  • the receiving side requests a retransmission to the transmitting side.
  • the retransmission request is made by toggling the NDI (New Data Indicator).
  • the transmitting side that receives the retransmission request retransmits the data. If no CRC error occurs on the receiving side, no retransmission request is made. If the transmitting side does not receive a retransmission request for a specified period of time, it assumes that no CRC error occurred on the receiving side.
  • the Broadcast Control Channel is a downlink channel for broadcasting system control information.
  • the logical channel BCCH is mapped to the broadcast channel (BCH), which is a transport channel, or the downlink shared channel (DL-SCH).
  • the Common Control Channel is a channel for transmitting control information between a communication terminal and a base station.
  • the CCCH is used when the communication terminal does not have an RRC connection with the network.
  • the CCCH is mapped to the downlink shared channel (DL-SCH), which is a transport channel.
  • the CCCH is mapped to the uplink shared channel (UL-SCH), which is a transport channel.
  • the Dedicated Traffic Channel is a one-to-one communication channel to a communication terminal for transmitting user information.
  • DTCH exists for both uplink and downlink.
  • DTCH is mapped to the uplink shared channel (UL-SCH), and in the downlink, it is mapped to the downlink shared channel (DL-SCH).
  • UL-SCH uplink shared channel
  • DL-SCH downlink shared channel
  • the location of a communication terminal is tracked in units of an area consisting of one or more cells. Location tracking is performed in order to track the location of the communication terminal even when it is in standby mode and to enable the communication terminal to be called, in other words, to allow the communication terminal to receive calls.
  • the area for tracking the location of this communication terminal is called a Tracking Area (TA).
  • TA Tracking Area
  • NR supports calling of communication terminals in a range that is smaller than a tracking area. This range is called the RAN Notification Area (RNA). Paging of communication terminals in the RRC_INACTIVE state, as described below, is performed within this range.
  • RNA RAN Notification Area
  • CA carrier aggregation
  • CCs component carriers
  • transmission bandwidths transmission bandwidths
  • a communication terminal UE When CA is configured, a communication terminal UE has only one RRC connection with the network (NW).
  • one serving cell provides NAS (Non-Access Stratum) mobility information and security input.
  • This cell is called a Primary Cell (PCell).
  • a Secondary Cell (SCell) is configured to form a set of serving cells together with the PCell.
  • a set of serving cells consisting of one PCell and one or more SCells is configured for one UE.
  • DC Dual Connectivity
  • the serving cells configured by the master base station may be collectively called the Master Cell Group (MCG), and the serving cells configured by the secondary base station may be collectively called the Secondary Cell Group (SCG).
  • MCG Master Cell Group
  • SCG Secondary Cell Group
  • the primary cell in the MCG or SCG is called a special cell (Special Cell: SpCell or SPCell).
  • the special cell in the MCG is called the PCell, and the special cell in the SCG is called the primary SCG cell (PSCell).
  • the base station pre-configures a portion of the carrier frequency band (hereinafter sometimes referred to as the Bandwidth Part (BWP)) for the UE, and the UE transmits and receives data to and from the base station using that BWP, thereby reducing power consumption in the UE.
  • BWP Bandwidth Part
  • SL communication also called PC5 communication
  • EPS Evolved Packet System
  • 5G core system 5G core system
  • SL communication communication is performed between terminals.
  • Services using SL communication include, for example, V2X (Vehicle-to-everything) service and proximity service.
  • V2X Vehicle-to-everything
  • SL communication not only direct communication between terminals but also communication between UE and NW via a relay has been proposed (see non-patent documents 26 and 28).
  • the physical sidelink broadcast channel (PSBCH) carries information related to the system and synchronization and is transmitted from the UE.
  • the physical sidelink control channel (PSCCH) carries control information from the UE for sidelink and V2X sidelink communications.
  • the physical sidelink shared channel (PSSCH) carries data from the UE for sidelink and V2X sidelink communications.
  • the transport channel used for SL (see Non-Patent Document 1) is explained below.
  • the sidelink broadcast channel (SL-BCH) has a predetermined transport format and is mapped to the PSBCH, which is a physical channel.
  • the sidelink shared channel supports broadcast transmissions.
  • the SL-SCH supports both UE autonomous resource selection and base station scheduled resource allocation. There is a collision risk with UE autonomous resource selection, and there is no collision when the UE is allocated dedicated resources by the base station.
  • the SL-SCH also supports dynamic link adaptation by changing the transmission power, modulation, and coding.
  • the SL-SCH is mapped to the PSSCH, which is a physical channel.
  • the Sidelink Broadcast Control Channel is a channel for sidelinks that is used to broadcast sidelink system information from one UE to other UEs.
  • the SBCCH is mapped to the SL-BCH, which is a transport channel.
  • one of the objectives of this disclosure is to enable improved reliability of data transmission and reception when a network switch occurs in a communication system configured to allow a UE to be simultaneously connected to multiple networks.
  • the communication system disclosed herein is a communication system compatible with a fifth-generation wireless access system, and includes an anchor network, which is a network with a user plane function that directly connects to a data network to which a communication terminal sends and receives data, and a non-anchor network, which is a network that connects to the data network via the anchor network, and has multiple protocol stacks for communication between the communication terminal and the data network.
  • an anchor network which is a network with a user plane function that directly connects to a data network to which a communication terminal sends and receives data
  • a non-anchor network which is a network that connects to the data network via the anchor network, and has multiple protocol stacks for communication between the communication terminal and the data network.
  • a communication system configured to allow a UE to be simultaneously connected to multiple networks, it is possible to improve the reliability of data transmission and reception when a network switch occurs.
  • FIG. 1 is a block diagram showing the overall configuration of an NR communication system 210 being discussed in 3GPP. This is a configuration diagram of DC by a base station connecting to an NG core.
  • FIG. 3 is a block diagram showing the configuration of a mobile terminal 202 shown in FIG. 2.
  • 3 is a block diagram showing a configuration of a base station 213 shown in FIG. 2.
  • a block diagram showing the configuration of the 5GC unit. 1 is a flowchart showing an outline of the process from cell search to standby operation performed by a communication terminal (UE) in an NR communication system.
  • UE communication terminal
  • “communication terminal device” includes not only mobile terminal devices such as mobile mobile phone terminal devices, but also stationary devices such as sensors.
  • “communication terminal device” may be simply referred to as “communication terminal.”
  • the gNB213 is connected to a 5G core unit (hereinafter sometimes referred to as a "5GC unit") 214 including an access and mobility management function (AMF), a session management function (SMF), or a user plane function (UPF) via an NG interface.
  • AMF access and mobility management function
  • SMF session management function
  • UPF user plane function
  • Control information and/or user data are communicated between the gNB213 and the 5GC unit 214.
  • the NG interface is a collective term for the N2 interface between the gNB213 and the AMF220, the N3 interface between the gNB213 and the UPF221, the N11 interface between the AMF220 and the SMF222, and the N4 interface between the UPF221 and the SMF222.
  • Multiple 5GC units 214 may be connected to one gNB213.
  • gNB213 are connected via the Xn interface, and control information and/or user data are communicated between gNB213.
  • the gNB 213 may be divided into a central unit (hereinafter sometimes referred to as CU) 215 and a distributed unit (hereinafter sometimes referred to as DU) 216.
  • CU central unit
  • DU distributed unit
  • One CU 215 is configured within the gNB 213.
  • One or more DUs 216 are configured within the gNB 213.
  • One DU 216 configures one or more cells.
  • the CU 215 is connected to the DU 216 via an F1 interface, and control information and/or user data are communicated between the CU 215 and the DU 216.
  • the F1 interface is composed of an F1-C interface and an F1-U interface.
  • a 5G communication system may include a Unified Data Management (UDM) function and a Policy Control Function (PCF) described in Non-Patent Document 10 (3GPP TS23.501).
  • the UDM and/or PCF may be included in the 5GC unit 214 in FIG. 2.
  • FIG. 4 is a block diagram showing the configuration of the mobile terminal 202 shown in FIG. 2.
  • the transmission process of the mobile terminal 202 shown in FIG. 4 will be described.
  • the control data from the control unit 310 and the user data from the application unit 302 are sent to the protocol processing unit 301. Buffering of the control data and the user data may be performed. Buffers for the control data and the user data may be provided 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, MAC, etc., for example, determining the destination base station in DC, etc., and adding a header in each protocol.
  • the Synchronization Signal is assigned a synchronization code that corresponds one-to-one to the PCI (Physical Cell Identifier) assigned to each cell. 1008 different PCIs are being considered. A communication terminal uses these 1008 different PCIs to synchronize and detect (identify) the PCI of the synchronized cell.
  • the communication terminal selects the cell with the best reception quality, for example, the cell with the highest reception power, that is, the best cell, from among the one or more cells detected up to step ST603.
  • the communication terminal also selects the beam with the best reception quality, for example, the beam with the highest reception power of the SS block, that is, the best beam.
  • the reception power of the SS block for each SS block identifier is used to select the best beam.
  • the communication terminal compares the TAC of SIB1 received in step ST605 with the TAC portion of the tracking area identifier (Tracking Area Identity: TAI) in the tracking area list already held by the communication terminal.
  • the tracking area list is also called a TAI list.
  • TAI is identification information for identifying a tracking area, and is composed of MCC (Mobile Country Code), MNC (Mobile Network Code), and TAC (Tracking Area Code).
  • MCC is a country code.
  • MNC is a network code.
  • TAC is the code number of the tracking area.
  • step ST606 If the comparison result in step ST606 shows that the TAC received in step ST605 is the same as the TAC included in the tracking area list, the communications terminal enters standby mode in the cell. If the comparison shows that the TAC received in step ST605 is not included in the tracking area list, the communications terminal requests a change of tracking area through the cell to the core network (EPC) including the MME, etc., in order to perform a Tracking Area Update (TAU).
  • EPC core network
  • MME Tracking Area Update
  • the mobile terminal transmits a random access preamble to the base station.
  • the random access preamble may be selected by the mobile terminal from within a predetermined range, or may be individually assigned to the mobile terminal and notified by the base station.
  • the base station transmits a random access response to the mobile terminal.
  • the random access response includes uplink scheduling information to be used in the third step, a terminal identifier to be used in the uplink transmission in the third step, etc.
  • the mobile terminal performs an uplink transmission to the base station.
  • the mobile terminal uses the information acquired in the second step.
  • the base station notifies the mobile terminal whether the collision has been resolved. If the mobile terminal is notified that there is no collision, it ends the random access process. If the mobile terminal is notified that there is a collision, it restarts the process from the first step.
  • the number of beams used by the base station 750 is eight, but the number of beams may be different from eight. Also, in the example shown in FIG. 8, the number of beams used simultaneously by the base station 750 is one, but it may be multiple.
  • the concept of Quasi-CoLocation is used to identify beams (see Non-Patent Document 14 (3GPP TS38.214)). That is, the beam is identified by information indicating which reference signal (e.g., SS block, CSI-RS) the beam can be considered to be the same as.
  • the information may include the type of information on the viewpoint of the beam being considered to be the same, such as Doppler shift, Doppler shift spread, average delay, average delay spread, and spatial Rx parameters (see Non-Patent Document 14 (3GPP TS38.214)).
  • Figure 9 shows an example of the connection configuration of a mobile terminal in SL communication.
  • UE805 and UE806 are present within the coverage 803 of base station 801.
  • UL/DL communication 807 is performed between base station 801 and UE805.
  • UL/DL communication 808 is performed between base station 801 and UE806.
  • SL communication 810 is performed between UE805 and UE806.
  • UE811 and UE812 are present outside the coverage 803.
  • SL communication 814 is performed between UE805 and UE811.
  • SL communication 816 is performed between UE811 and UE812.
  • the data that has undergone encoding processing in the encoder unit 304 is modulated in the modulation unit 305.
  • Precoding in MIMO may be performed in the modulation unit 305.
  • the modulated data is converted into a baseband signal, and then output to the frequency conversion unit 306, where it is converted into a wireless transmission frequency. Thereafter, a transmission signal is transmitted from the antennas 307-1 to 307-4 to the base station 801.
  • a base station that supports IAB (hereinafter, sometimes referred to as an IAB base station) is composed of an IAB donor CU, which is the CU of a base station that operates as an IAB donor providing IAB functions, an IAB donor DU, which is the DU of a base station that operates as an IAB donor, and an IAB node that is connected to the IAB donor DU and to the UE using a radio interface.
  • An F1 interface is provided between the IAB node and the IAB donor CU (see Non-Patent Document 2).
  • the configuration of the IAB donor DU As an example of the configuration of the IAB donor DU, a configuration similar to that of DU 216 is used.
  • BAP layer processing is performed, such as adding a BAP header to downstream data, routing to an IAB node, and removing the BAP header from upstream data.
  • the decoded data is passed to the protocol processing unit 403, where protocol processing such as MAC and RLC used for communication with the IAB node 904 is performed, for example, operations such as removing the header in each protocol are performed.
  • protocol processing such as MAC and RLC used for communication with the IAB node 904
  • routing to the IAB donor DU 902 using the BAP header is performed, and protocol processing such as RLC and MAC used for communication with the IAB donor DU 902, for example, operations such as adding a header for each protocol, are performed.
  • the data that has been subjected to protocol processing is passed to the encoder unit 405, where encoding processing such as error correction is performed.
  • the encoded data is modulated by the modulation unit 406.
  • Precoding in MIMO may be performed by the modulation unit 406.
  • the modulated data is converted into a baseband signal, and then output to the frequency conversion unit 407, where it is converted into a radio transmission frequency.
  • a transmission signal is transmitted to the IAB donor DU 902 from the antennas 408-1 to 408-4.
  • the same processing is performed in downlink communication from the IAB donor CU 901 to the UE 905.
  • IAB node 904 In IAB node 904, the same sending and receiving processing as in IAB node 903 is performed. In protocol processing unit 403 of IAB node 903, processing of the BAP layer is performed, such as adding a BAP header in upstream communication and routing to IAB node 904, and removing the BAP header in downstream communication.
  • FIG. 11 is a configuration diagram showing an example in which a UE is connected to multiple networks.
  • the UE is connected to each of NW1090 and NW1091.
  • base station #1, AMF #1, UPF #1, SMF #1, SEPP (Security Edge Protection Proxy: see non-patent document 10) #1, PCF #1, UDM #1, and anchor UPF all belong to NW1090
  • base station #2, AMF #2, UPF #2, SMF #2, SEPP #2, PCF #2, and UDM #2 all belong to NW1091.
  • the anchor UPF is connected to the DN.
  • the following problem occurs during this switching. That is, the switching of the network occurs before all data from the network connected before the switching has reached the UE, and there is a risk that the data will be lost.
  • the protocol stacks that the UE has may be protocol stacks below the PDU (Protocol Data Unit) layer.
  • the IP address of the UE may be changed.
  • the UE may have multiple IP addresses.
  • FIG. 12 is a diagram showing an example of a protocol stack between a UE and an anchor UPF.
  • the UE has multiple protocol stacks below the PDU layer.
  • FIG. 12 shows an example configuration of a first protocol stack for the UE to connect to NW1090 shown in FIG. 11 and communicate with a DN, and a second protocol stack for the UE to connect to NW1091 shown in FIG. 11 and communicate with a DN.
  • the anchor UPF may have multiple protocol stacks below GTP-U (GPRS (General Packet Radio Service) Tunneling Protocol for User Plane). This, for example, eliminates the need to change the IP address when the UE switches networks.
  • GTP-U General Packet Radio Service Tunneling Protocol for User Plane
  • Another example of a protocol stack that both UEs have may be a protocol stack below the PDCP layer.
  • the anchor UPF may have multiple protocol stacks below GTP-U. This makes it possible to avoid, for example, the complexity of associating QoS (Quality of Service) flows and data in both networks.
  • QoS Quality of Service
  • protocol stack Another example of a protocol stack that the UE has in both places may be a protocol stack below the RLC layer.
  • the anchor UPF may have multiple protocol stacks below GTP-U. This, for example, can reduce memory usage in the UE.
  • the NF of the NW may decide whether to perform NW switching while maintaining both protocols.
  • the notification from the NW to the UE may include information indicating whether to perform NW switching while maintaining both protocols.
  • the UE may use the information to perform NW switching while maintaining both protocols, or may decide not to perform the NW switching. This, for example, can improve flexibility in the communication system.
  • Information regarding the configuration of both protocol stacks may be provided in the UE.
  • the information may be provided, for example, as UE capabilities.
  • the UE may notify the information to an NF of the NW, for example, the AMF.
  • the AMF may notify the information to an SMF.
  • An NF of the NW for example, the AMF and/or the SMF, may use the information to instruct the UE to perform measurements.
  • the measurements instructed to the UE may be measurements related to the RAN, QoS (Quality of Service) monitoring (see Non-Patent Documents 10 and 31), or QoE (Quality of Experience) measurements (see Non-Patent Document 2).
  • the above (1) enables the network to quickly determine whether or not settings for both protocol stacks are possible, for example.
  • the above (5) may be, for example, information indicating whether the information regarding the settings of both protocol stacks is information regarding the source network or the destination network. This allows, for example, the NF that determines the network switching to quickly determine the destination network.
  • the NW may notify the UE of information regarding the settings of the protocol stack in its own NW.
  • the information may include, for example, information similar to (1) to (6) above.
  • the information may include information in which the UE is read as the own NW in (1) to (6) above.
  • the UE may use the information to determine the NW to camp on. This allows, for example, the UE to connect to a highly reliable NW.
  • the UE may establish a protocol stack between both NWs in response to a NW switching instruction from the NF of the NW.
  • the UE may respond to the NW switching instruction to the NW in response to the establishment of the protocol stack between the two NWs.
  • the response from the UE may be made to the NF of the anchor NW, the NF of the switching destination NW, or the NF of the switching source NW.
  • the aforementioned NF may be an SMF or an AMF.
  • the NF of the NW that receives the response may notify the NF of the switching destination NW of information regarding the response from the UE.
  • the notification may be made via the SMF.
  • the switching destination NW may start receiving uplink data from the UE or starting transmitting downlink data to the UE in response to the notification.
  • the source network may send a packet with an end marker to the UE.
  • the end marker may be added by the anchor UPF or by an intermediate UPF (a UPF that is not the anchor UPF) of the source network.
  • the UE may release the protocol stack between the source network and the UE.
  • the release may be triggered, for example, by the reception of an end marker packet, or by the reception of packets up to the end marker packet.
  • the UE may notify the NF of the NW of information regarding the release.
  • the notification from the UE may be made to the NF of the anchor network, to the NF of the destination network, or to the NF of the source network.
  • the aforementioned NF may be an SMF or an AMF.
  • the NF of the NW that receives the notification may notify the NF of the source network of information regarding the notification from the UE.
  • the source network may release the protocol stack between the UE and the UE upon the notification.
  • the notification may be made in response to a network switching instruction.
  • the UE may respond to a network switching instruction multiple times.
  • the UE may switch the destination of the uplink data from the source network to the destination network.
  • the switching may be triggered, for example, by receiving a PDU session establishment request, by receiving a PDU session change request, by transmitting a signaling acknowledgment for the PDU session establishment request, by transmitting a signaling acknowledgment for the PDU session change request, or by establishing a protocol stack between both networks.
  • FIG. 16 and 17 are sequence diagrams showing an example of a network switching operation that maintains the protocols of both networks.
  • FIG. 16 shows the first half of the sequence
  • FIG. 17 shows the second half of the sequence.
  • the UE's connection destination is switched from NW1091, which is a non-anchor network, to NW1090, which is an anchor network.
  • NW1091 which is a non-anchor network
  • NW1090 which is an anchor network.
  • FIG. 16 and FIG. 17 an example is shown in which the anchor SMF detects QoS deterioration in NW1091, which is a non-anchor network, and the anchor SMF decides to switch networks.
  • base station #1, AMF #1, UPF #1, SMF #1, PCF #1, UDM #1, and anchor UPF belong to NW1090
  • base station #2, AMF #2, UPF #2, SMF #2, PCF #2, and UDM #2 belong to NW1091.
  • Step ST1196 shows data transmission and reception between the UE and base station #2, step ST1197 between base station #2 and the UPF #2, step ST1198 between the UPF #2 and the anchor UPF, and step ST1199 between the anchor UPF and the DN.
  • SMF#1 detects QoS deterioration.
  • SMF#1 detects QoS deterioration for UPF#2.
  • SMF#1 may detect the QoS deterioration using the QoS monitoring report from the anchor UPF and the QoS monitoring report from UPF#2.
  • step ST1206 shown in FIG. 16 SMF#1 decides to switch the network that will be the data path. In the example shown in FIG. 16, SMF#1 decides to switch the data path passing through UPF#2 to NW1090.
  • SMF#1 may select whether to perform NW switching while maintaining both protocols.
  • SMF#1 determines that the UE will perform NW switching while maintaining the protocol stacks with both NW1090 and NW1091.
  • SMF#1 instructs SMF#2 to switch the network.
  • the instruction may use signaling of a PDU session release request or signaling of a PDU session change request.
  • the instruction may include information about the UE, information about the PDU session, information about the QoS flow, information about QoS deterioration, information about the UPF related to QoS deterioration, a network switching request, or information about the network after the path switching.
  • the instruction in step ST1210 may include information indicating that the protocols of both networks are to be maintained, or may include information regarding the protocol to be maintained.
  • the information regarding the protocol to be maintained may be, for example, below the PDU layer, below SDAP, below PDCP, or below RLC.
  • procedure 1100 shown in FIG. 16 a process for establishing a connection with the UPF in NW 1090 is performed. Procedure 1100 will be described below.
  • FIG. 18 is a sequence diagram showing an example of procedure 1100 in FIG. 16.
  • SMF#1 selects a UPF.
  • SMF#1 selects UPF#1 and decides to use UPF#1.
  • a procedure for establishing a session management policy association is performed between SMF#1 and PCF#1.
  • This procedure may be, for example, the procedure disclosed in section 4.16.4 of non-patent document 31 (3GPP TS23.502).
  • a procedure for changing the session management policy association may be performed.
  • the procedure for changing the session management policy association may be, for example, the procedure disclosed in section 4.16.5 of non-patent document 31 (3GPP TS23.502).
  • FIG. 19 is a sequence diagram showing an example of procedure 1111 in FIG. 16.
  • the UE may notify the base station of information related to the PDCP SN of the PDCP PDU to be transmitted.
  • the base station may be the source base station, the destination base station, or both of the above.
  • the notification may be performed, for example, as a PDCP Status PDU.
  • the notification may be performed using RRC signaling, as an RLC Status PDU, as MAC signaling, or as L1/L2 signaling.
  • the notification may include information about the other network, may include information about the identification of the base station of the other network, or may include information about the PDCP entity of the base station of the other network. This allows, for example, the base station of the other network to quickly understand that the notification is addressed to its own base station.
  • the notification may include information about the PDU session or about the QoS flow. This allows, for example, the other base station to quickly understand the traffic.
  • the notification may be performed between base stations.
  • the notification may be performed via AMF, SMF, SEPP, or the above-mentioned multiple methods.
  • the notification may be performed directly between base stations.
  • the base station may inquire about information regarding the counterpart base station from a DNS (Domain Name System).
  • the DNS may notify the base station of the information regarding the counterpart base station. This may, for example, reduce the amount of processing in the UE.
  • the application layer may route the destination network. This allows, for example, to improve flexibility in routing.
  • a protocol stack may be provided that branches below the PDU layer.
  • a UE may have multiple PDU layers.
  • a UE may have multiple IP addresses or multiple MAC addresses.
  • the protocol stack may have a configuration similar to that of the protocol stack disclosed in FIG. 12.
  • a protocol stack may be provided that branches below the SDAP layer.
  • the UE may have multiple SDAP layers.
  • the protocol stack may have a configuration similar to that of the protocol stack disclosed in FIG. 13, for example. This eliminates the need for the UE to have multiple IP addresses, for example, and as a result, the complexity of the UE is reduced compared to the previous case.
  • the PDU layer of the UE may perform routing based on, for example, the amount of buffer stored in its own PDU layer. For example, if the buffer amount is greater than or equal to a predetermined threshold, the UE may transmit data to one of the two networks, and if the buffer amount is less than or equal to the predetermined threshold, the UE may transmit data to one of the networks. In the above case, the network to which the uplink data is sent may be referred to as the main network below. As another example, if the buffer amount is greater than or equal to a predetermined threshold, the UE may transmit data to one of the two networks, and if the buffer amount is less than or equal to the predetermined threshold, the UE may transmit data to the other network.
  • the aforementioned one of the networks may be an anchor network or a non-anchor network. This, for example, can improve flexibility in communications.
  • the buffer amount may include the buffer amount of a lower layer.
  • it may include the buffer amount of the SDAP layer, the buffer amount of the PDCP layer, the buffer amount of the RLC layer, the buffer amount of the MAC layer or lower, the buffer amount in the PHY layer, or the multiple buffer amounts mentioned above. This makes it possible to perform routing that takes into account the entire buffer amount of the UE, for example.
  • the lower layer of the UE may notify the PDU layer of the buffer amount of the lower layer.
  • the lower layer may be SDAP, PDCP, the RLC layer, or the MAC layer.
  • the buffer amount may be the buffer amount per PDU session or the buffer amount per QoS flow. This allows, for example, the PDU layer to quickly grasp the buffer amount of the lower layer.
  • QoS may be used for routing.
  • a UE may transmit data to a network with good QoS. This makes it possible to ensure QoS for upstream communication, for example.
  • the UE may perform QoS monitoring.
  • the UE may use the results of the QoS monitoring to perform the routing.
  • the QoS monitored by the UE may include, for example, information about upstream and/or downstream packet delays, congestion, data rate, packet delay variance, round-trip packet delay, and upstream delay in the UE (e.g., the difference between the time when upstream data should be sent and the time when it is actually sent).
  • a threshold may be used for routing using QoS. For example, if the QoS in one NW is better than or equal to a predetermined threshold, the NW may continue to be used, and if it is worse than or equal to the predetermined threshold, data may be transmitted to another NW.
  • the one NW may be an anchor NW or a non-anchor NW. This makes it possible to ensure QoS in upstream transmissions. Hysteresis may be provided for the threshold. This makes it possible to prevent, for example, frequent switching of the destination NW for upstream data.
  • Routing using QoS flows may be performed for each QoS flow. For example, a QoS flow that requires latency may pass through a network with low latency, and a QoS flow that requires reliability may pass through a network with high reliability. This makes it possible to ensure QoS for each QoS flow, for example.
  • the aforementioned threshold may be determined by the PCF.
  • the PCF of the anchor network (hereinafter, may be referred to as the anchor PCF) may determine the threshold.
  • the anchor PCF may notify the anchor SMF of the threshold.
  • the anchor SMF may notify the UE of the threshold.
  • the notification from the anchor SMF may be performed via the anchor AMF or via the anchor base station.
  • the threshold value may be determined by the SMF.
  • the anchor SMF may determine the threshold value.
  • the anchor SMF may determine the threshold value using a policy notified by the anchor PCF.
  • the anchor SMF may notify the UE of the threshold value. The notification from the anchor SMF to the UE may be performed in the same manner as described above.
  • the threshold may be determined by an AMF, e.g., an anchor AMF, or by a base station, e.g., an anchor base station.
  • the AMF and/or the base station may notify the UE of the threshold.
  • the aforementioned threshold value may be determined by the NWDAF (Network Data Analytics Function). This allows for flexible threshold value determination based on, for example, the NW situation.
  • NWDAF Network Data Analytics Function
  • the NWDAF may notify the UE of the threshold value. The notification may be performed via the AMF, via the base station, or directly to the UE.
  • the UE's SDAP layer may route the destination network.
  • a protocol stack may be provided that branches below the PDCP layer.
  • the UE may have multiple PDCP layers.
  • the protocol stack may have a configuration similar to that of the protocol stack disclosed in FIG. 14. This reduces the complexity of the UE by having a PDCP layer that faces each base station of each network, and reduces the amount of processing by the UE by consolidating the SDAP layer into one.
  • the buffer amount may include the buffer amount of a lower layer.
  • it may include the buffer amount of the PDCP layer, the buffer amount of the RLC layer, the buffer amount of the MAC layer or lower, the buffer amount of the PHY layer, or the multiple buffer amounts mentioned above. This makes it possible to perform routing that takes into account the entire buffer amount of the UE, for example.
  • the buffer amount for each PDU session may be used, or the buffer amount for each QoS flow may be used. This allows flexible routing for each traffic, for example.
  • the instruction may include information regarding the switching of the main network, or may include information regarding the threshold value disclosed in embodiment 2.
  • the information regarding the switching of the main network may include, for example, information indicating that the main network is to be switched. This makes it possible, for example, to reduce the size of signaling.
  • the information may include information regarding the network after switching. This makes it possible, for example, for the UE to quickly grasp the network after switching.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

Un système de communication d'après l'invention comprend : un réseau d'ancrage qui est un réseau ayant une fonction de plan utilisateur pour une connexion directe avec un réseau de données d'une destination d'émission/réception de données d'un terminal de communication ; et un réseau de non-ancrage qui est un réseau qui se connecte au réseau de données par l'intermédiaire du réseau d'ancrage. Lors de la commutation d'un réseau connecté à un autre réseau, le terminal de communication utilise une pluralité de piles de protocoles pour se connecter à la fois au réseau d'ancrage et au réseau de non-ancrage pour passer à un état permettant de communiquer avec le réseau de données, et termine ensuite la communication avec le réseau de données par l'intermédiaire du réseau connecté.
PCT/JP2024/044750 2024-01-05 2024-12-18 Système de communication Pending WO2025146774A1 (fr)

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Citations (5)

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WO2016163432A1 (fr) * 2015-04-10 2016-10-13 京セラ株式会社 Équipement utilisateur et dispositif de communication sans fil
US11095559B1 (en) * 2019-09-18 2021-08-17 Cisco Technology, Inc. Segment routing (SR) for IPV6 (SRV6) techniques for steering user plane (UP) traffic through a set of user plane functions (UPFS) with traffic handling information
EP4114115A1 (fr) * 2020-09-15 2023-01-04 Huawei Technologies Co., Ltd. Procédé de traitement de message et dispositif associé
EP4191951A1 (fr) * 2017-11-27 2023-06-07 Huawei Technologies Co., Ltd. Procédé, appareil et système de traitement de session
US20230224795A1 (en) * 2020-09-17 2023-07-13 Huawei Technologies Co., Ltd. Communication method and apparatus

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Publication number Priority date Publication date Assignee Title
WO2016163432A1 (fr) * 2015-04-10 2016-10-13 京セラ株式会社 Équipement utilisateur et dispositif de communication sans fil
EP4191951A1 (fr) * 2017-11-27 2023-06-07 Huawei Technologies Co., Ltd. Procédé, appareil et système de traitement de session
US11095559B1 (en) * 2019-09-18 2021-08-17 Cisco Technology, Inc. Segment routing (SR) for IPV6 (SRV6) techniques for steering user plane (UP) traffic through a set of user plane functions (UPFS) with traffic handling information
EP4114115A1 (fr) * 2020-09-15 2023-01-04 Huawei Technologies Co., Ltd. Procédé de traitement de message et dispositif associé
US20230224795A1 (en) * 2020-09-17 2023-07-13 Huawei Technologies Co., Ltd. Communication method and apparatus

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