WO2021162333A1 - Procédé de traitement de données de mbs et appareil associé - Google Patents

Procédé de traitement de données de mbs et appareil associé Download PDF

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Publication number
WO2021162333A1
WO2021162333A1 PCT/KR2021/001435 KR2021001435W WO2021162333A1 WO 2021162333 A1 WO2021162333 A1 WO 2021162333A1 KR 2021001435 W KR2021001435 W KR 2021001435W WO 2021162333 A1 WO2021162333 A1 WO 2021162333A1
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Prior art keywords
mbs
session
base station
data
terminal
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PCT/KR2021/001435
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English (en)
Korean (ko)
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홍성표
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주식회사 케이티
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Priority claimed from KR1020210014051A external-priority patent/KR20210104563A/ko
Application filed by 주식회사 케이티 filed Critical 주식회사 케이티
Publication of WO2021162333A1 publication Critical patent/WO2021162333A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W4/00—Services specially adapted for wireless communication networks; Facilities therefor
    • H04W4/06—Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W76/00—Connection management
    • H04W76/40—Connection management for selective distribution or broadcast

Definitions

  • the present disclosure relates to an operation for processing MBS data.
  • Multimedia Broadcast Multicast Services is a technology that can provide mobile broadcasting services using a cellular mobile communication network.
  • Technology to provide services is being developed.
  • MBMS is an end-to-end/point-to-multipoint transmission service.
  • the MBMS service adopts a multi-cell transmission method in which a plurality of base stations transmit the same packet at the same time, and when this multi-cell transmission method is used, a terminal receiving the service has diversity in the physical layer. ) may be beneficial.
  • the efficiency may vary depending on the number of terminals receiving the corresponding data. Therefore, a technique for controlling the MBS session based on NR and providing service continuity is required.
  • the present disclosure devised in the above background proposes a technique for flexibly providing a multicast/broadcast service (MBS) based on NR.
  • MMS multicast/broadcast service
  • a method for a terminal to receive MBS (Multicast / Broadcast Service) data the step of receiving MBS data through an MBS radio bearer mapped to an MBS session in a source cell and a cell change from a source cell to a target cell
  • MBS Multicast / Broadcast Service
  • a method comprising triggering and receiving MBS data via one of an MBS radio bearer mapped to an MBS session in a target cell or a radio bearer mapped to a PDU session associated with the MBS session.
  • a radio bearer to transmit MBS data when a terminal receiving MBS data accesses according to a cell change, determining a radio bearer to transmit MBS data based on whether MBS is supported
  • a method comprising transmitting MBS data through one of an MBS radio bearer mapped to the MBS session or a radio bearer mapped to a PDU session associated with the MBS session according to the steps and determination.
  • the receiving unit that receives MBS data through the MBS radio bearer mapped to the MBS session in the source cell and the source cell to the target cell trigger a cell change It provides a terminal device that further receives MBS data through one of an MBS radio bearer mapped to an MBS session in a target cell or a radio bearer mapped to a PDU session associated with an MBS session in the target cell.
  • MBS Multicast / Broadcast Service
  • a control unit that determines a radio bearer to transmit MBS data based on whether MBS is supported and a transmitter for transmitting MBS data through one of an MBS radio bearer mapped to the MBS session or a radio bearer mapped to a PDU session associated with the MBS session according to the determination.
  • MBS Multicast/Broadcast Service
  • the present disclosure has an effect of flexibly providing a multicast/broadcast service (MBS) based on NR.
  • MMS multicast/broadcast service
  • FIG. 1 is a diagram schematically illustrating a structure of an NR wireless communication system to which this embodiment can be applied.
  • FIG. 2 is a diagram for explaining a frame structure in an NR system to which this embodiment can be applied.
  • FIG 3 is a diagram for explaining a resource grid supported by a radio access technology to which this embodiment can be applied.
  • FIG. 4 is a diagram for explaining a bandwidth part supported by a radio access technology to which the present embodiment can be applied.
  • FIG. 5 is a diagram exemplarily illustrating a synchronization signal block in a radio access technology to which the present embodiment can be applied.
  • FIG. 6 is a diagram for explaining a random access procedure in a radio access technology to which the present embodiment can be applied.
  • FIG. 8 is a diagram exemplarily illustrating a logical structure in MBMS.
  • FIG. 9 is a diagram for explaining a procedure for starting an MBMS session.
  • FIG. 10 is a diagram for explaining an operation of a terminal according to an embodiment.
  • FIG. 11 is a diagram for explaining an operation of a base station according to an embodiment.
  • FIG. 12 is a diagram illustrating a downlink layer 2 structure in an LTE system.
  • FIG. 13 is a diagram exemplarily illustrating MBS radio bearer configuration information according to an embodiment.
  • FIG. 14 is a diagram exemplarily illustrating MBS radio bearer configuration information according to another embodiment.
  • 15 is a diagram illustrating a layer 2 structure according to an exemplary embodiment.
  • 16 is a diagram illustrating an example of a layer 2 structure for NR MBS data transmission/reception.
  • 17 is a diagram illustrating a terminal configuration according to an embodiment.
  • FIG. 18 is a diagram illustrating a configuration of a base station according to an embodiment.
  • temporal precedence relationship such as "after”, “after”, “after”, “before”, etc.
  • a flow precedence relationship when a flow precedence relationship is described, it may include a case where it is not continuous unless “immediately” or "directly” is used.
  • a wireless communication system in the present specification refers to a system for providing various communication services such as voice and data packets using radio resources, and may include a terminal, a base station, or a core network.
  • the present embodiments disclosed below may be applied to a wireless communication system using various wireless access technologies.
  • the present embodiments are CDMA (code division multiple access), FDMA (frequency division multiple access), TDMA (time division multiple access), OFDMA (orthogonal frequency division multiple access), SC-FDMA (single carrier frequency division multiple access)
  • CDMA code division multiple access
  • FDMA frequency division multiple access
  • TDMA time division multiple access
  • OFDMA orthogonal frequency division multiple access
  • SC-FDMA single carrier frequency division multiple access
  • the wireless access technology may mean not only a specific access technology, but also a communication technology for each generation established by various communication consultation organizations such as 3GPP, 3GPP2, WiFi, Bluetooth, IEEE, and ITU.
  • CDMA may be implemented with a radio technology such as universal terrestrial radio access (UTRA) or CDMA2000.
  • UTRA universal terrestrial radio access
  • CDMA2000 Code Division Multiple Access 2000
  • TDMA may be implemented with a radio technology such as global system for mobile communications (GSM)/general packet radio service (GPRS)/enhanced datarates for GSM evolution (EDGE).
  • OFDMA may be implemented with a wireless technology such as Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802-20, and evolved UTRA (E-UTRA).
  • IEEE 802.16m is an evolution of IEEE 802.16e, and provides backward compatibility with a system based on IEEE 802.16e.
  • UTRA is part of the universal mobile telecommunications system (UMTS).
  • 3rd generation partnership project (3GPP) long term evolution (LTE) is a part of evolved UMTS (E-UMTS) that uses evolved-UMTSterrestrial radio access (E-UTRA), and employs OFDMA in the downlink and SC- in the uplink.
  • E-UMTS evolved UMTS
  • E-UTRA evolved-UMTSterrestrial radio access
  • OFDMA OFDMA
  • SC- SC- in the uplink
  • FDMA is employed.
  • the present embodiments may be applied to currently disclosed or commercialized radio access technologies, or may be applied to radio access technologies currently under development or to be developed in the future.
  • the terminal in the present specification is a comprehensive concept meaning a device including a wireless communication module for performing communication with a base station in a wireless communication system, WCDMA, LTE, NR, HSPA and IMT-2020 (5G or New Radio), etc. It should be interpreted as a concept including all of UE (User Equipment), MS (Mobile Station), UT (User Terminal), SS (Subscriber Station), wireless device, and the like in GSM.
  • the terminal may be a user portable device such as a smart phone depending on the type of use, and in a V2X communication system may mean a vehicle, a device including a wireless communication module in the vehicle, and the like.
  • a machine type communication (Machine Type Communication) system, it may mean an MTC terminal, an M2M terminal, a URLLC terminal, etc. equipped with a communication module to perform machine type communication.
  • a base station or cell in the present specification refers to an end that communicates with a terminal in terms of a network, a Node-B (Node-B), an evolved Node-B (eNB), gNode-B (gNB), a Low Power Node (LPN), Sector, site, various types of antennas, base transceiver system (BTS), access point, point (eg, transmission point, reception point, transmission/reception point), relay node (Relay Node) ), mega cell, macro cell, micro cell, pico cell, femto cell, RRH (Remote Radio Head), RU (Radio Unit), and small cell (small cell), etc.
  • the cell may mean including a BWP (Bandwidth Part) in the frequency domain.
  • the serving cell may mean the Activation BWP of the UE.
  • the base station can be interpreted in two ways. 1) in relation to the radio area, it may be the device itself providing a mega cell, a macro cell, a micro cell, a pico cell, a femto cell, or a small cell, or 2) may indicate the radio area itself.
  • the devices providing a predetermined radio area are controlled by the same entity, or all devices interacting to form a radio area cooperatively are directed to the base station.
  • a point, a transmission/reception point, a transmission point, a reception point, etc. become an embodiment of a base station according to a configuration method of a wireless area.
  • the radio area itself in which the signal is received or transmitted from the point of view of the user terminal or the neighboring base station may be indicated to the base station.
  • a cell is a component carrier having a coverage of a signal transmitted from a transmission/reception point or a coverage of a signal transmitted from a transmission/reception point, and the transmission/reception point itself.
  • Uplink refers to a method of transmitting and receiving data by the terminal to and from the base station
  • downlink Downlink (Downlink, DL, or downlink) refers to a method of transmitting and receiving data to and from the terminal by the base station do.
  • a downlink may mean a communication or communication path from a multi-transmission/reception point to a terminal
  • an uplink may mean a communication or communication path from the terminal to a multi-transmission/reception point.
  • the transmitter in the downlink, the transmitter may be a part of multiple transmission/reception points, and the receiver may be a part of the terminal.
  • the transmitter in the uplink, the transmitter may be a part of the terminal, and the receiver may be a part of the multi-transmission/reception point.
  • the uplink and downlink transmit and receive control information through a control channel such as a Physical Downlink Control CHannel (PDCCH), a Physical Uplink Control CHannel (PUCCH), etc., and a Physical Downlink Shared CHannel (PDSCH), a Physical Uplink Shared CHannel (PUSCH), etc.
  • a control channel such as a Physical Downlink Control CHannel (PDCCH), a Physical Uplink Control CHannel (PUCCH), etc.
  • PDSCH Physical Downlink Shared CHannel
  • PUSCH Physical Uplink Shared CHannel
  • 5G (5th-Generation) communication technology is developed to meet the requirements of ITU-R's next-generation wireless access technology.
  • 3GPP develops LTE-A pro, which improves LTE-Advanced technology according to the requirements of ITU-R as a 5G communication technology, and a new NR communication technology separate from 4G communication technology.
  • LTE-A pro and NR both refer to 5G communication technology.
  • 5G communication technology will be described focusing on NR unless a specific communication technology is specified.
  • NR operation scenario various operation scenarios were defined by adding consideration of satellites, automobiles, and new verticals to the existing 4G LTE scenarios. It is deployed in a range and supports the mMTC (Massive Machine Communication) scenario that requires a low data rate and asynchronous connection, and the URLLC (Ultra Reliability and Low Latency) scenario that requires high responsiveness and reliability and supports high-speed mobility. .
  • mMTC Massive Machine Communication
  • URLLC Ultra Reliability and Low Latency
  • NR discloses a wireless communication system to which a new waveform and frame structure technology, low latency technology, mmWave support technology, and forward compatible technology are applied.
  • various technical changes are presented in terms of flexibility in order to provide forward compatibility. The main technical features of NR will be described with reference to the drawings below.
  • FIG. 1 is a diagram schematically illustrating a structure of an NR system to which this embodiment can be applied.
  • the NR system is divided into a 5G Core Network (5GC) and an NR-RAN part, and the NG-RAN controls the user plane (SDAP/PDCP/RLC/MAC/PHY) and UE (User Equipment) It consists of gNBs and ng-eNBs that provide planar (RRC) protocol termination.
  • the gNB interconnects or gNBs and ng-eNBs are interconnected via an Xn interface.
  • gNB and ng-eNB are each connected to 5GC through the NG interface.
  • 5GC may be configured to include an Access and Mobility Management Function (AMF) in charge of a control plane such as terminal access and mobility control functions, and a User Plane Function (UPF) in charge of a control function for user data.
  • AMF Access and Mobility Management Function
  • UPF User Plane Function
  • NR includes support for both frequency bands below 6 GHz (FR1, Frequency Range 1) and frequency bands above 6 GHz (FR2, Frequency Range 2).
  • gNB means a base station that provides NR user plane and control plane protocol termination to a terminal
  • ng-eNB means a base station that provides E-UTRA user plane and control plane protocol termination to a terminal.
  • the base station described in this specification should be understood as encompassing gNB and ng-eNB, and may be used as a meaning to distinguish gNB or ng-eNB as needed.
  • a CP-OFDM waveform using a cyclic prefix is used for downlink transmission, and CP-OFDM or DFT-s-OFDM is used for uplink transmission.
  • OFDM technology is easy to combine with MIMO (Multiple Input Multiple Output), and has advantages of using a low-complexity receiver with high frequency efficiency.
  • the NR transmission numerology is determined based on sub-carrier spacing and cyclic prefix (CP), and the ⁇ value is used as an exponential value of 2 based on 15 kHz as shown in Table 1 below. is changed to
  • the NR pneumatology can be divided into five types according to the subcarrier spacing. This is different from the fact that the subcarrier interval of LTE, one of the 4G communication technologies, is fixed at 15 kHz. Specifically, subcarrier intervals used for data transmission in NR are 15, 30, 60, and 120 kHz, and subcarrier intervals used for synchronization signal transmission are 15, 30, 120, 240 kHz. In addition, the extended CP is applied only to the 60 kHz subcarrier interval. On the other hand, as for the frame structure in NR, a frame having a length of 10 ms is defined, which is composed of 10 subframes having the same length of 1 ms.
  • FIG. 2 is a frame in an NR system to which this embodiment can be applied. It is a drawing for explaining the structure.
  • a slot is fixedly composed of 14 OFDM symbols in the case of a normal CP, but the length in the time domain of the slot may vary according to the subcarrier interval.
  • the slot in the case of a numerology having a 15 kHz subcarrier interval, the slot is 1 ms long and is composed of the same length as the subframe.
  • a slot in the case of numerology having a 30 kHz subcarrier interval, a slot consists of 14 OFDM symbols, but two slots may be included in one subframe with a length of 0.5 ms. That is, the subframe and the frame are defined to have a fixed time length, and the slot is defined by the number of symbols, so that the time length may vary according to the subcarrier interval.
  • NR defines a basic unit of scheduling as a slot, and also introduces a mini-slot (or a sub-slot or a non-slot based schedule) to reduce transmission delay in a radio section.
  • a mini-slot or a sub-slot or a non-slot based schedule
  • the mini-slot is for efficient support of the URLLC scenario and can be scheduled in units of 2, 4, or 7 symbols.
  • NR defines uplink and downlink resource allocation at a symbol level within one slot.
  • a slot structure capable of transmitting HARQ ACK/NACK directly within a transmission slot is defined, and this slot structure is named as a self-contained structure and will be described.
  • NR is designed to support a total of 256 slot formats, of which 62 slot formats are used in 3GPP Rel-15.
  • a common frame structure constituting an FDD or TDD frame is supported through a combination of various slots.
  • a slot structure in which all symbols of a slot are set to downlink a slot structure in which all symbols are set to uplink
  • a slot structure in which downlink symbols and uplink symbols are combined are supported.
  • NR supports that data transmission is scheduled to be distributed in one or more slots.
  • the base station may inform the terminal whether the slot is a downlink slot, an uplink slot, or a flexible slot using a slot format indicator (SFI).
  • the base station may indicate the slot format by indicating the index of the table configured through UE-specific RRC signaling using SFI, and may indicate dynamically through Downlink Control Information (DCI) or statically or through RRC. It can also be ordered quasi-statically.
  • DCI Downlink Control Information
  • an antenna port In relation to a physical resource in NR, an antenna port, a resource grid, a resource element, a resource block, a bandwidth part, etc. are considered do.
  • An antenna port is defined such that a channel on which a symbol on an antenna port is carried can be inferred from a channel on which another symbol on the same antenna port is carried.
  • the two antenna ports are QC/QCL (quasi co-located or QC/QCL) quasi co-location).
  • the wide range characteristic includes one or more of delay spread, Doppler spread, frequency shift, average received power, and received timing.
  • FIG 3 is a diagram for explaining a resource grid supported by a radio access technology to which this embodiment can be applied.
  • a resource grid may exist according to each numerology.
  • the resource grid may exist according to an antenna port, a subcarrier interval, and a transmission direction.
  • a resource block consists of 12 subcarriers, and is defined only in the frequency domain.
  • a resource element is composed of one OFDM symbol and one subcarrier. Accordingly, as in FIG. 3 , the size of one resource block may vary according to the subcarrier interval.
  • NR defines "Point A" serving as a common reference point for a resource block grid, a common resource block, a virtual resource block, and the like.
  • FIG. 4 is a diagram for explaining a bandwidth part supported by a radio access technology to which the present embodiment can be applied.
  • a bandwidth part may be designated within the carrier bandwidth and used by the terminal.
  • the bandwidth part is associated with one numerology and is composed of a subset of continuous common resource blocks, and may be dynamically activated according to time.
  • a maximum of four bandwidth parts are configured in the terminal, respectively, in uplink and downlink, and data is transmitted/received using the activated bandwidth part at a given time.
  • the uplink and downlink bandwidth parts are set independently, and in the case of an unpaired spectrum, to prevent unnecessary frequency re-tunning between downlink and uplink operations
  • the downlink and uplink bandwidth parts are set in pairs to share a center frequency.
  • the terminal accesses the base station and performs a cell search and random access procedure in order to perform communication.
  • Cell search is a procedure in which the UE synchronizes the cell of the corresponding base station using a synchronization signal block (SSB) transmitted by the base station, obtains a physical layer cell ID, and obtains system information.
  • SSB synchronization signal block
  • FIG. 5 is a diagram exemplarily illustrating a synchronization signal block in a radio access technology to which the present embodiment can be applied.
  • the SSB consists of a primary synchronization signal (PSS) and a secondary synchronization signal (SSS) occupying 1 symbol and 127 subcarriers, respectively, and a PBCH spanning 3 OFDM symbols and 240 subcarriers.
  • PSS primary synchronization signal
  • SSS secondary synchronization signal
  • the UE receives the SSB by monitoring the SSB in the time and frequency domains.
  • SSB can be transmitted up to 64 times in 5ms.
  • a plurality of SSBs are transmitted using different transmission beams within 5 ms, and the UE performs detection on the assumption that SSBs are transmitted every 20 ms when viewed based on one specific beam used for transmission.
  • the number of beams that can be used for SSB transmission within 5 ms time may increase as the frequency band increases.
  • up to 4 SSB beams can be transmitted in 3 GHz or less, and SSB can be transmitted using up to 8 different beams in a frequency band of 3 to 6 GHz and up to 64 different beams in a frequency band of 6 GHz or more.
  • Two SSBs are included in one slot, and the start symbol and the number of repetitions within the slot are determined according to the subcarrier interval as follows.
  • the SSB is not transmitted at the center frequency of the carrier bandwidth, unlike the SS of the conventional LTE. That is, the SSB may be transmitted in a place other than the center of the system band, and a plurality of SSBs may be transmitted in the frequency domain when wideband operation is supported. Accordingly, the UE monitors the SSB using a synchronization raster, which is a candidate frequency location for monitoring the SSB.
  • the carrier raster and synchronization raster which are the center frequency location information of the channel for initial access, are newly defined in NR, and the synchronization raster has a wider frequency interval than the carrier raster, so that the terminal can support fast SSB search.
  • the UE may acquire the MIB through the PBCH of the SSB.
  • MIB Master Information Block
  • MIB includes minimum information for the terminal to receive the remaining system information (RMSI, Remaining Minimum System Information) broadcast by the network.
  • the PBCH includes information on the position of the first DM-RS symbol in the time domain, information for the UE to monitor SIB1 (eg, SIB1 neurology information, information related to SIB1 CORESET, search space information, PDCCH related parameter information), offset information between the common resource block and the SSB (the position of the absolute SSB in the carrier is transmitted through SIB1), and the like.
  • SIB1 eg, SIB1 neurology information, information related to SIB1 CORESET, search space information, PDCCH related parameter information
  • offset information between the common resource block and the SSB the position of the absolute SSB in the carrier is transmitted through SIB1
  • the SIB1 neurology information is equally applied to some messages used in the random access procedure for accessing the base station after the UE completes the cell search procedure.
  • the neurology information of SIB1 may be applied to at least one of messages 1 to 4 for the random access procedure.
  • the aforementioned RMSI may mean System Information Block 1 (SIB1), and SIB1 is periodically broadcast (eg, 160 ms) in the cell.
  • SIB1 includes information necessary for the UE to perform an initial random access procedure, and is periodically transmitted through the PDSCH.
  • CORESET Control Resource Set
  • the UE checks scheduling information for SIB1 by using SI-RNTI in CORESET, and acquires SIB1 on PDSCH according to the scheduling information.
  • SIBs other than SIB1 may be transmitted periodically or may be transmitted according to the request of the terminal.
  • FIG. 6 is a diagram for explaining a random access procedure in a radio access technology to which the present embodiment can be applied.
  • the terminal transmits a random access preamble for random access to the base station.
  • the random access preamble is transmitted through the PRACH.
  • the random access preamble is transmitted to the base station through a PRACH consisting of continuous radio resources in a specific slot that is periodically repeated.
  • a contention-based random access procedure is performed, and when performing random access for beam failure recovery (BFR), a contention-free random access procedure is performed.
  • BFR beam failure recovery
  • the terminal receives a random access response to the transmitted random access preamble.
  • the random access response may include a random access preamble identifier (ID), a UL grant (uplink radio resource), a temporary C-RNTI (Temporary Cell - Radio Network Temporary Identifier), and a Time Alignment Command (TAC). Since one random access response may include random access response information for one or more terminals, the random access preamble identifier may be included to inform which terminal the included UL Grant, temporary C-RNTI, and TAC are valid.
  • the random access preamble identifier may be an identifier for the random access preamble received by the base station.
  • the TAC may be included as information for the UE to adjust uplink synchronization.
  • the random access response may be indicated by a random access identifier on the PDCCH, that is, RA-RNTI (Random Access - Radio Network Temporary Identifier).
  • the terminal Upon receiving the valid random access response, the terminal processes information included in the random access response and performs scheduled transmission to the base station. For example, the UE applies the TAC and stores the temporary C-RNTI. In addition, data stored in the buffer of the terminal or newly generated data is transmitted to the base station by using the UL grant. In this case, information for identifying the terminal should be included.
  • the terminal receives a downlink message for contention resolution.
  • the downlink control channel in NR is transmitted in a control resource set (CORESET) having a length of 1 to 3 symbols, and transmits up/down scheduling information, slot format index (SFI), transmit power control (TPC) information, etc. .
  • CORESET control resource set
  • SFI slot format index
  • TPC transmit power control
  • CORESET Control Resource Set
  • the UE may decode the control channel candidates by using one or more search spaces in the CORESET time-frequency resource.
  • QCL Quasi CoLocation
  • CORESET may exist in various forms within a carrier bandwidth within one slot, and CORESET may consist of up to three OFDM symbols in the time domain.
  • CORESET is defined as a multiple of 6 resource blocks up to the carrier bandwidth in the frequency domain.
  • the first CORESET is indicated through the MIB as part of the initial bandwidth part configuration to receive additional configuration information and system information from the network.
  • the terminal may receive and configure one or more pieces of CORESET information through RRC signaling.
  • frequencies, frames, subframes, resources, resource blocks, regions, bands, subbands, control channels, data channels, synchronization signals, various reference signals, various signals or various messages related to NR can be interpreted in various meanings used in the past or present or used in the future.
  • NR conducted in 3GPP recently has been designed to satisfy various QoS requirements required for each segmented and detailed usage scenario as well as an improved data rate compared to LTE.
  • eMBB enhanced Mobile BroadBand
  • mMTC massive MTC
  • URLLC Ultra Reliable and Low Latency Communications
  • Each usage scenario has different requirements for data rates, latency, reliability, coverage, etc.
  • numerology eg subcarrier spacing, subframe, TTI, etc.
  • radio resource unit unit
  • a subframe is defined as a type of time domain structure.
  • SCS Sub-Carrier Spacing
  • the NR subframe is an absolute reference time duration, and slots and mini-slots may be defined as time units that are the basis of actual uplink/downlink data scheduling.
  • an arbitrary slot consists of 14 symbols.
  • all symbols may be used for DL transmission, or all symbols may be used for UL transmission, or may be used in the form of DL portion + (gap) + UL portion according to the transmission direction of the slot. have.
  • a mini-slot composed of fewer symbols than the aforementioned slot is defined.
  • a short time-domain scheduling interval for mini-slot-based uplink/downlink data transmission/reception may be configured, or a long time-domain scheduling interval for uplink/downlink data transmission/reception through slot aggregation may be configured. have.
  • it is difficult to satisfy the latency requirement if 1ms (14 symbols)-based slot-based scheduling defined in a numerology-based frame structure with a small SCS value such as 15kHz is performed. can Accordingly, scheduling that can satisfy the requirements of URLLC can be performed based on defining a mini-slot composed of fewer OFDM symbols than a slot composed of 14 symbols.
  • MBMS Multimedia Broadcast Multicast Service
  • 3GPP which develops mobile communication standards, has developed LTE broadcast/multicast standards for video broadcasting from Rel-9. Since then, standards have been standardized to support other services such as public safety, IoT, and V2X in LTE.
  • NR which is currently standardized, Rel-15 and Rel-16 standards do not support MBMS. It is judged that MBMS-related standards need to be further developed in the NR standards of future releases.
  • the conventional MBMS based on LTE provided two transmission schemes, a Multimedia Broadcast multicast service Single Frequency Network (MBSFN) transmission scheme and a Single Cell Point To Multipoint (SC-PTM) transmission scheme.
  • MMSFN Multimedia Broadcast multicast service Single Frequency Network
  • SC-PTM Single Cell Point To Multipoint
  • the MBSFN transmission method is suitable for providing media broadcasting in a large pre-planned area (MBSFN area).
  • the MBSFN area is statically configured. Organized by O&M, for example. And it cannot be dynamically adjusted according to the user distribution.
  • Synchronized MBMS transmission is provided within the MBSFN area, and aggregation is supported for MBMS transmission from multiple cells.
  • Each MCH scheduling is performed by a multi-cell/multicast coordination entity (MCE), and a single transport block is used for each TTI for MCH transmission.
  • MCE multi-cell/multicast coordination entity
  • all MCH transport blocks use MBSFN resources in their subframes.
  • MTCH and MCCH may be multiplexed on the same MCH.
  • MTCH and MCCH use RLC-UM mode. Even if all radio resources are not used in the frequency domain, unicast and multiplexing are not allowed in the same subframe. As such, the MBSFN transmission method is difficult to dynamically adjust, making it difficult to
  • the SC-PTM transmission method was developed as a method to improve the inefficiency of the MBSFN transmission method.
  • MBMS is transmitted within single cell coverage.
  • One SC-MCCH and one or more SC-MTCH(s) are mapped to the DL-SCH. Scheduling is provided by the base station.
  • SC-MCCH and SC-MTCH are each indicated by one logical channel specific RNTI (SC-RNTI, G-RNTI) on the PDCCH.
  • SC-MTCH and SC-MCCH use RLC-UM mode.
  • a single transmission is used for the DL-SCH to which the SC-MCCH and the SC-MTCH are mapped, but blind HARQ repetition or RLC repetition is not provided. Therefore, SC-PTM transmission was difficult to provide reliable transmission.
  • a logical structure as shown in FIG. 8 may be used to provide MBMS through the above-described transmission methods.
  • FIG. 8 is a diagram exemplarily illustrating a logical structure in MBMS.
  • each entity performs the following functions.
  • the MBMS GW uses IP Multicast as a means of forwarding MBMS user data to the eNB (The MBMS GW uses IP Multicast as the means of forwarding MBMS user data to the eNB).
  • MBMS GW performs MBMS Session Control Signaling (Session start / update / stop) for E-UTRAN through MME (The MBMS GW performs MBMS Session Control Signaling (Session start/update/stop) towards the E-UTRAN via MME).
  • the MCE does not establish a radio bearer of a new MBMS service(s) if the radio resources are not sufficient for the corresponding MBMS service(s) or if radio resources can be preempted from other radio bearer(s) of the MBMS service in progress according to ARP.
  • the MCE decides not to establish the radio bearer(s) of the new MBMS service(s) if the radio resources are not sufficient for the corresponding MBMS service(s) or may pre-empt radio resources from other radio bearer (s) of ongoing MBMS service(s) according to ARP).
  • suspension of MBMS session(s) within MBSFN area(s) within MBSFN area(s) based eg the ARP based on the calculation result for ARP and/or corresponding MBMS service(s) and/or on the counting results for the corresponding MBMS service(s)).
  • FIG. 9 is a diagram for explaining a procedure for starting an MBMS session.
  • an MBMS session is initiated through step 9 .
  • the MME transmits the MBMS session start request message to the MCE(s) controlling the eNB in the target MBMS service area.
  • This message contains the IP multicast address, session properties and the minimum time to wait before passing the first data, and if possible a list of cell IDs (The MME sends MBMS session start request message to the MCE(s) controlling eNBs in the The message includes the IP multicast address, session attributes and the minimum time to wait before the first data delivery, and includes the list of cell identities if available).
  • the MCE decides whether to use SC-PTM or MBSFN to carry the MBMS bearer over the air interface.
  • the MCE confirms the reception of the MBMS session start request to the MME. This message can be sent before step 4.
  • the MCE only confirms the reception of the MBMS session start request to the MME after the MME receives at least one confirmation from the eNB(s) (ie, step 4) (The MCE confirms the reception of the MBMS Session)
  • This message can be transmitted before the step 4.
  • the MCE only confirms the reception of the MBMS Session Start request to the MME, after the MCE receives at least one confirmation from the eNB( s) (ie Step 4)).
  • the MCE includes the SC-PTM information in the MBMS Session Start Request message sent to the corresponding eNB (In SC-PTM operation, the MCE includes the SC-PTM information, in the MBMS Session Start Request message to the relevant eNBs).
  • the eNB checks whether radio resources are sufficient to establish new MBMS service(s) in the area it controls. Otherwise, the eNB may decide not to establish a radio bearer of MBMS service(s) or may preempt radio resources from other radio bearer(s) according to ARP. The eNB confirms reception of the MBMS session start message (In SC-PTM operation, the eNB checks whether the radio resources are sufficient for the establishment of new MBMS service(s) in the area it controls. If not, eNB decides not to establish the radio bearers of the MBMS service(s), or may pre-empt radio resources from other radio bearer(s) according to ARP. eNB confirms the reception of the MBMS Session Start message).
  • Step 5 and 6 are only applicable to MBSFN operation.
  • the MCE transmits the MBMS scheduling information message including the updated MCCH information carrying the configuration information of the MBMS service to the eNB.
  • This message can be transmitted before step 3 (MCE sends the MBMS Scheduling Information message to the eNB including the updated MCCH information which carries the MBMS service's configuration information. This message can be transmitted before the step 3).
  • the eNB confirms the reception of the MBMS Scheduling Information message.
  • eNB notifies MBMS session start to UE through MCCH change notification and updated MCCH information delivering configuration information of MBMS service (eNB indicates MBMS session start to UEs by MCCH change notification and updated MCCH information which carries the MBMS service's configuration information).
  • the eNB joins the IP multicast group to receive the MBMS User Plane data.
  • eNB sends the MBMS data to radio interface.
  • a complex control procedure was required between the core network entities and the wireless network.
  • a separate MCE entity for controlling a base station within a target MBMS service area had to determine a transmission method among the MBSFN method and the SC-PTM method and perform scheduling. Accordingly, it is difficult to dynamically turn on/off MBMS transmission directly for a cell associated with a specific base station. For example, even when there is only one UE receiving data through MBMS transmission in a specific cell, data must be transmitted inefficiently through MBMS transmission.
  • Radio bearer eg MBMS radio bearer, SC-PTM radio bearer
  • SC-PTM radio bearer SC-PTM radio bearer setup / setup procedure for receiving MBMS data in LTE network is, for example, when starting an MBMS session (upon start of the MBMS session, upon (re-)entry) of the corresponding MBSFN service area, upon entering a cell providing via SC-MRB a MBMS service in which the UE has interest, upon becoming interested in the MBMS service, upon removal of UE capability limitations inhibiting reception of the concerned service) may be disclosed, and may be applied through system information/MCCH/SC-MCCH message reception.
  • the RRC connection state terminal interested in receiving the MBMS service in the LTE network informs the network of the MBMS interest information through the RRC message.
  • the source BS transmits the MBMS interest information of the UE to the target BS in the handover preparation process.
  • the UE that is receiving or interested to receive MBMS via MBSFN or SC-PTM informs the network about its MBMS interest via a RRC message and the network does its best to ensure that the UE is able to receive MBMS and unicast services subject to the UE's capabilities:
  • the UE indicates the frequencies which provide the service(s) that the UE is receiving or is interested to receive simultaneously, and which can be received simultaneously in accordance with the UE capabilities.
  • the UE also indicates the list of services that the UE is receiving or is interested to receive on the indicated frequencies.
  • the UE indicates its MBMS interest at RRC connection establishment (the UE does not need to wait until AS security is activated), and whenever the set of frequencies on which the UE is interested in receiving MBMS services has changed compared with the last indication sent to the network (eg due to a change of user interest or of service availability), and whenever the list of MBMS services that the UE is interested in receiving has changed compared with the last indication sent to the network.
  • the UE may only indicate its interest when the PCell provides SystemInformationBlockType15 and after having acquired SystemInformationBlockType15 of the current PCell.
  • the UE may indicate its MBMS interest even if the current configured serving cell(s) do not prevent it from receiving the MBMS services it is interested in.
  • the source eNB transfers the MBMS interest of the UE, if available, to the target eNB.
  • the UE reads SystemInformationBlockType15 before updating its MBMS interest. If SystemInformationBlockType15 is provided on the target cell but not on the source cell, the UE indicates its MBMS interest after handover.)
  • the present disclosure provides a method and apparatus for flexibly controlling various multicast/broadcast services based on NR.
  • MBS Multicast/Broadcast Service
  • TS 38.331 3GPP NR RRC standard
  • corresponding content specified in the standard which is a well-known technology, may be included in the present disclosure.
  • the MBS service providing method according to the present invention is not only a large-scale broadcast service provided through a single frequency network (SFN), but also V2X, public safety, IoT service, software upgrade, file transmission, etc. provided through one or more cells It can be applied to any multicast service.
  • SFN single frequency network
  • V2X public safety, IoT service, software upgrade, file transmission, etc.
  • Each embodiment described in this specification is a unicast transmission cell (eg, a cell that is not currently performing multicast/broadcast transmission for a specific MBS session or multicast/broadcast transmission) in a multicast/broadcast transmission cell. It can be applied when moving to a cell that does not support In addition, each embodiment may be applied when the terminal moves from a multicast/broadcast transmission cell to a multicast/broadcast transmission cell.
  • a unicast transmission cell eg, a cell that is not currently performing multicast/broadcast transmission for a specific MBS session or multicast/broadcast transmission
  • each embodiment may be applied when the terminal moves from a multicast/broadcast transmission cell to a multicast/broadcast transmission cell.
  • Each of the embodiments described below may be applied individually or in combination in any combination.
  • FIG. 10 is a diagram for explaining an operation of a terminal according to an embodiment.
  • a terminal receiving multicast/broadcast service (MBS) data performs a step of receiving MBS data through an MBS radio bearer mapped to an MBS session in a source cell (S1010).
  • MBS multicast/broadcast service
  • the terminal may receive multicast/broadcast service data of interest from a specific cell or base station. For example, the terminal may receive MBS data through a radio bearer mapped to the MBS session. As another example, the terminal may receive MBS data mapped to a PDU session associated with the MBS session. That is, the UE may receive MBS data through a multicast/broadcast radio bearer or through a unicast radio bearer.
  • the UE may perform a step of triggering a cell change from the source cell to the target cell (S1020).
  • a situation such as a cell change or a base station change may occur according to the movement of the terminal.
  • the base station may determine and instruct the handover of the terminal.
  • the base station may instruct a cell change according to the movement of the terminal.
  • the terminal may change a cell or a base station for any reason.
  • a cell change or base station change situation is described and described as handover or cell change.
  • the terminal may perform a cell change operation from the source cell to the target cell according to the instruction of the base station.
  • the source cell and the target cell may be cells controlled by the same base station or cells controlled by different base stations.
  • the terminal may perform the step of receiving MBS data through one of the MBS radio bearer mapped to the MBS session in the target cell or the radio bearer mapped to the PDU session associated with the MBS session (S1030).
  • the UE when the UE performs a cell change to the target cell, the UE needs to receive MBS data also in the target cell.
  • the UE may receive MBS data received from the source cell through the MBS radio bearer mapped to the MBS session of the target cell in the target cell.
  • the UE may receive MBS data received from the source cell through a radio bearer (DRB) mapped to a PDU session connected to the MBS session of the target cell in the target cell.
  • DRB radio bearer
  • MBS data received through the MBS radio bearer mapped to the MBS session may be received using a Radio Network Temporary Identifier (RNTI) addressing the MBS session data.
  • RNTI Radio Network Temporary Identifier
  • MBS data received through a radio bearer mapped to a PDU session associated with the MBS session may be received using a Cell-Radio Network Temporary Identifier (C-RNTI).
  • C-RNTI Cell-Radio Network Temporary Identifier
  • the PDU session associated with the MBS session may be established or modified when the terminal initiates a procedure for joining the MBS session. For example, the terminal transmits a PDU session establishment/modification request message to the core network entity through the base station. Thereafter, by receiving a PDU session establishment/modification command message through the base station, the PDU session associated with the MBS session may be established or modified in the terminal.
  • Whether the terminal receives MBS data through the MBS radio bearer in the target cell or receives MBS data through the radio bearer mapped to the PDU session associated with the MBS session may be determined depending on whether the target cell supports MBS.
  • MBS data received from the target cell may be received through a radio bearer mapped to a PDU session associated with the MBS session.
  • the UE may receive MBS data through the MBS radio bearer.
  • MBS data can be seamlessly performed through the MBS radio bearer or the radio bearer mapped to the PDU session regardless of whether the changed cell is supported.
  • MBS data can be continuously received through the multicast/broadcast method.
  • MBS data can be continuously received regardless of cell change even in the same method (unicast to unicast, multicast/broadcast to multicast/broadcast).
  • the MBS data reception operation for each method described above will be described in more detail below.
  • the operation of setting the radio bearer and the operation of linking the MBS session and the radio bearer will be separately described in more detail below.
  • FIG. 11 is a diagram for explaining an operation of a base station according to an embodiment.
  • the terminal may receive the multicast/broadcast service data of interest from the source cell or the base station.
  • the terminal may receive MBS data through a radio bearer mapped to the MBS session.
  • the terminal may receive MBS data mapped to a PDU session associated with the MBS session. That is, the UE may receive MBS data through a multicast/broadcast radio bearer or through a unicast radio bearer.
  • a situation such as a cell change or a base station change may occur according to the movement of the terminal.
  • the source base station may determine and instruct the handover of the terminal.
  • the base station may instruct a cell change according to the movement of the terminal.
  • the terminal may change a cell or a base station for any reason.
  • the base station may determine a method for transmitting MBS data based on whether the corresponding base station supports MBS in order to provide continuity of MBS data reception of the terminal. Alternatively, the base station may determine the transmission method of MBS data to be transmitted to the terminal according to the instruction of the core network entity.
  • the base station may perform the step of transmitting MBS data through one of the MBS radio bearer mapped to the MBS session or the radio bearer mapped to the PDU session associated with the MBS session according to the determination (S1120).
  • the base station may transmit MBS data in a multicast/broadcast manner or may transmit MBS data in a unicast manner.
  • the base station may transmit MBS data through the MBS radio bearer mapped to the MBS session.
  • the base station may transmit MBS data through a radio bearer mapped to a PDU session associated with the MBS session.
  • MBS data transmitted through the MBS radio bearer mapped to the MBS session may be transmitted using a Radio Network Temporary Identifier (RNTI) addressing the MBS session data.
  • RNTI Radio Network Temporary Identifier
  • MBS data transmitted through a radio bearer mapped to a PDU session associated with the MBS session may be transmitted using a Cell-Radio Network Temporary Identifier (C-RNTI).
  • C-RNTI Cell-Radio Network Temporary Identifier
  • MBS data may be transmitted through a radio bearer mapped to a PDU session associated with the MBS session.
  • the MBS data may be transmitted through the MBS radio bearer mapped to the MBS session.
  • the MBS data transmission scheme may be determined in consideration of additional factors such as the number of MBS data receiving terminals in the cell, in addition to whether the base station is supported.
  • MBS data can be seamlessly performed through the MBS radio bearer or the radio bearer mapped to the PDU session regardless of whether the changed cell is supported.
  • the PDU session associated with the MBS session may be established or modified when the terminal initiates a procedure for joining the MBS session.
  • the base station receives the PDU session establishment/modification request message from the terminal and transmits it to the core network entity. Thereafter, the base station may transmit a PDU session setup/modification command message received from the core network entity to the terminal through an RRC message.
  • the terminal may receive the PDU session establishment/modification command message through the base station, and may set or modify the PDU session associated with the MBS session to the terminal.
  • the MBS data transmission operation for each method described above will be described in more detail below.
  • the operation of setting the radio bearer and the operation of linking the MBS session and the radio bearer will be separately described in more detail below.
  • an MBS session In order to transmit MBS data (e.g. media, video, software downloading etc.), an MBS session must be established between the terminal and the core network entity.
  • MBS session the session between the multicast/broadcast receiving terminal and the UPF (or any MBS user plane function having an application function and interface for an external network MBS application server or an internal network MBS service) is denoted as an MBS session.
  • MBS session the session between the multicast/broadcast receiving terminal and the UPF (or any MBS user plane function having an application function and interface for an external network MBS application server or an internal network MBS service)
  • MBS session This is for convenience of description and may be replaced with any term meaning a multicast/broadcast session between the UE and the UPF.
  • data through the MBS session will be described and described as MBS data or MBS session data.
  • the MBS session may be a one-way session dedicated to the downlink.
  • the MBS session may be added with an uplink session (or a bidirectional session) associated with the downlink session.
  • a unicast session e.g. PDU session
  • the MBS session may be requested and established by terminal initiation or network initiation.
  • MBS data may be transmitted transparently through the 5G system (5GS). This is because it is desirable to support MBS by recycling the existing structure of the 5G system as much as possible.
  • the (MBS) application server of the external network can perform signaling with the control plane entity (e.g. AMF, SMF) of the 5G core network through the Network Exposure Function (NEF) (or PCF).
  • NEF Network Exposure Function
  • the MBS Service Function can perform signaling with the control plane entities (eg AMF, SMF) of the 5G core network through the Policy Control Function (PCF).
  • PCF Policy Control Function
  • the application server of the external network can transmit MBS data to the base station through UPF (or MBS UPF).
  • UPF or MBS UPF
  • the application function (AF) of the core network or the MBS function of the core network may transmit MBS data to the base station through the UPF (or MBS UPF).
  • the transmission efficiency of multicast/broadcast delivery of the MBS session increases.
  • the multicast/broadcast delivery has lower transmission efficiency compared to the unicast transmission. That is, the MBS session has lower wireless transmission efficiency compared to unicast-based transmission in order to support data reception of multiple users.
  • a cell change may occur according to the movement of the corresponding terminal.
  • the cell to which the UE is handed over may not transmit the corresponding MBS data in a multicast/broadcast manner.
  • the cell to which the terminal is handed over at this time may be a cell that does not support multicast/broadcast transmission.
  • the cell to which the terminal is handed over at this time may be transmitting the corresponding MBS data in a multicast/broadcast manner.
  • coordination between the source base station and the target base station may be provided.
  • a multicast/broadcast radio bearer for a specific MBS session may be mapped to a unicast radio bearer in the terminal through coordination between base stations and configured.
  • the UE may receive data for the corresponding MBS session at a specific time (or after a specific time) through the unicast radio bearer.
  • an RRC message including a handover command is received, random access is initiated to the target base station (Msg1/MsgA transmission), random first/initial uplink transmission to the target base station, successful random access to the target base station, the source cell is released, It may be one of the time points of applying/setting/reconfiguring/completing any L2 entity/configuration to the target cell and completing the handover.
  • the target base station does not establish a tunnel (associated with QoS flows of the MBS session) between the UPF associated with the corresponding MBS session and the base station in the target base station, for starting the corresponding MBS session or for the corresponding MBS session
  • a tunnel between the UPF and the target base station, or to instruct/request establishment/modification of a unicast session (eg PDU session) associated with an MBS session, or to establish/set-up/modify/change the corresponding MBS session
  • specific indication information may be transmitted to AMF/SMF.
  • the AMF/SMF may perform the session establishment/modification procedure by sending a request message for setting/modifying the MBS session and/or the associated unicast session (e.g. PDU session) to the base station.
  • the AMF/SMF may perform an MBS session start procedure for starting a corresponding MBS session with the base station.
  • a tunnel (associated with QoS flows of the MBS session) between the UPF associated with the corresponding MBS session and the base station is established in the target base station, and the tunnel is multicast/broadcast in the target cell If it is associated with a multicast/broadcast (point-to-multipoint) radio bearer for (point-to-multipoint) transmission, it can be configured by mapping the multicast/broadcast radio bearer to the corresponding terminal.
  • a tunnel (associated with QoS flows of the MBS session) between the UPF associated with the corresponding MBS session and the base station is established in the target base station, and the tunnel is unicast (point-to-point) in the target cell. ), if it is associated with a radio bearer for transmission, the tunnel between the UPF associated with the corresponding MBS session and the target base station can be mapped and configured as a new unicast (point-to-point) radio bearer for the corresponding terminal.
  • a method of mapping a multicast/broadcast radio bearer and a unicast radio bearer associated with an MBS session and a method of coordination between base stations will be described in more detail in the following embodiments.
  • a base station/cell change may occur according to the movement of the terminal. For example, when the terminal is receiving data in the multicast/broadcast method for a specific MBS session, according to the movement of the terminal, the cell changes to the cell in which data is transmitted in the multicast/broadcast method for the corresponding MBS session This can happen. For another example, when the terminal is receiving data in the multicast/broadcast method for a specific MBS session, the cell to transmit data in the unicast method for the corresponding MBS session according to the movement of the terminal (eg, the current multicast/broadcast method) A cell change may occur to a cell that does not transmit data in a broadcast method or does not support a multicast/broadcast method).
  • the cell to transmit data in the unicast method for the corresponding MBS session according to the movement of the terminal eg, the current multicast/broadcast
  • a cell change may occur to a cell that does not transmit data in this method or does not support the multicast/broadcast method.
  • a cell change may occur to the cell transmitting data in the multicast/broadcast method for the corresponding MBS session according to the movement of the terminal.
  • the RRC connected state terminal receiving data for a specific MBS session may receive MBS data through the source cell during cell change.
  • the terminal may receive data for the corresponding MBS session through the multicast/broadcast radio bearer through the source cell until a specific time point.
  • a specific point in time is RRC message reception including handover command, random access procedure start to target base station (Msg1/MsgA transmission), random initial/initial uplink transmission to target base station, successful random access to target base station, source cell release , arbitrary L2 entity/configuration application/setup/reconfiguration/completion to the target cell, handover completion, and system information and/or control information for the corresponding MBS session in the target cell (eg MCCH, SC-MCCH for MBS session Control logical channel, RRC message) may be one of the times of reception.
  • the terminal may receive data for the corresponding MBS session through the source cell through the unicast radio bearer until a specific time point.
  • a specific point in time is RRC message reception including handover command, random access procedure start to target base station (Msg1/MsgA transmission), successful random access to target base station, source cell release, arbitrary L2 entity/configuration application/ One of the times of setup/reconfiguration/completion, handover completion, and reception of system information or control information for the corresponding MBS session (eg RRC message belonging to the control logical channel for the MBS session similar to MCCH, SC-MCCH) from the target cell can be
  • the terminal may complete successful random access to the target base station and maintain the source base station connection until releasing the source cell.
  • the terminal may maintain the connection to the source base station until the initial/initial uplink transmission to the target base station.
  • Such information for instructing the connection maintenance of the terminal may be transmitted from the source base station to the target base station.
  • Information for instructing connection maintenance of the terminal may be transmitted from the target base station to the source base station.
  • Information for instructing the connection maintenance of the terminal may be transmitted from the target base station to the terminal.
  • the UE may operate as follows.
  • the terminal may continue to receive data through the multicast/broadcast radio bearer for the MBS session from the source base station until releasing the source cell and a successful random access procedure for the target base station.
  • the UE configures one RLC entity for the target having the same configuration as the RLC entity for the source.
  • the terminal sets one logical channel configuration for the target having the same configuration as the logical channel for the source.
  • the terminal creates a new MAC entity for the target/target base station.
  • the UE creates one RLC entity and one associated traffic logical channel for the unicast DRB associated with the MBS session for the target/target base station.
  • the UE configures one PDCP entity for the target having the same configuration as the PDCP entity for the source.
  • the UE reconfigures a PDCP entity having separate security and ROHC functions for the source and the target.
  • the terminal maintains some/all of the source configuration until the source base station is released.
  • the UE may report the handover failure through the source without reestablishing the RRC connection.
  • the radio resource configuration of the source cell is released and uplink/downlink transmission/reception is stopped.
  • the UE may stop some operations related to the source base station (in the source PCell or in the source cellgroup). For example, one or more operations among system information update, paging reception, and short message reception for NR may be stopped.
  • the UE when a cell is changed from a multicast/broadcast transmission cell to a multicast/broadcast transmission cell, the UE may operate as follows.
  • the terminal may continue to receive data through the multicast/broadcast radio bearer for the MBS session from the source base station until releasing the source cell and a successful random access procedure for the target base station.
  • the UE configures one RLC entity for the target having the same configuration as the RLC entity for the source.
  • the terminal sets one logical channel configuration for the target having the same configuration as the logical channel for the source.
  • the terminal creates a new MAC entity for the target/target base station.
  • the UE creates one RLC entity and one associated traffic logical channel for the multicast/broadcast radio bearer associated with the MBS session for the target/target base station.
  • the UE configures one PDCP entity for the target having the same configuration as the PDCP entity for the source.
  • the UE reconfigures a PDCP entity having separate security and ROHC functions for the source and the target.
  • the terminal maintains some/all of the source configuration until the source base station is released.
  • the UE may report the handover failure through the source without reestablishing the RRC connection.
  • the radio resource configuration of the source cell is released and uplink/downlink transmission/reception is stopped.
  • the UE may stop some operations related to the source base station (in the source PCell or in the source cellgroup). For example, one or more operations among system information update, paging reception, and short message reception for NR may be stopped.
  • the UE when a cell is changed from a unicast transmission cell to a multicast/broadcast transmission cell, the UE may operate as follows.
  • the terminal may continue to receive data through the unicast radio bearer for the MBS session from the source base station until releasing the source cell and until a successful random access procedure for the target base station.
  • the UE configures one RLC entity for the target having the same configuration as the RLC entity for the source.
  • the terminal sets one logical channel configuration for the target having the same configuration as the logical channel for the source.
  • the terminal creates a new MAC entity for the target/target base station.
  • the UE creates one RLC entity and one associated traffic logical channel for the multicast/broadcast radio bearer for the radio bearer associated with the MBS session for the target/target base station.
  • the UE configures one PDCP entity for the target having the same configuration as the PDCP entity for the source.
  • the UE reconfigures a PDCP entity having separate security and ROHC functions for the source and the target.
  • the terminal maintains some/all of the source configuration until the source base station is released.
  • the UE may report the handover failure through the source without reestablishing the RRC connection.
  • the radio resource configuration of the source cell is released and uplink/downlink transmission/reception is stopped.
  • the UE may stop some operations related to the source base station (in the source PCell or in the source cellgroup). For example, one or more operations among system information update, paging reception, and short message reception for NR may be stopped.
  • the source base station transmits information about the MBS session that the terminal is receiving in a multicast/broadcast manner in a handover request message or a handover preparation information message (HandoverPreparationInformation RRC container, inter-node RRC message) included in the handover request message.
  • a handover preparation information message HandoverPreparationInformation RRC container, inter-node RRC message
  • MBS context information information about the MBS session that the terminal is receiving. This is for convenience of description and may be replaced with any other terminology.
  • MBS context information includes MBS session information, QoS flow information included in the corresponding MBS session, Transport Network Layer (TNL) information, the corresponding MBS data transmission/cast type in the corresponding base station/cell associated with the corresponding base station, the corresponding cell identification information, It may include one or more information among the corresponding base station identification information, the terminal identification information receiving the corresponding MBS data, one multicast address (eg IP multicast address), and the number of terminal(s) that have joined the corresponding MBS session.
  • MBS session information includes at least one of MBS service ID, MBS session ID, TMGI, session-ID, IP multicast address, slice information (eg S-NSSAI) associated with the corresponding MBS session, MBS service area identifier, and MBS service cell identification information.
  • QoS flow information includes QoS information for the corresponding MBS session (eg 5QI/QCI, QoS flow Identifier, GBR QoS flow information (Maximum Flow Bit Rate, Guaranteed Flow Bit Rate, Maximum Packet Loss Rate), Allocation and Retention Priority, Priority Level Packet It may include one or more of Delay Budget and Packet Error Rate TNL information may include one of IP multicast address, IP source address and GTP DL TEID
  • the identification information of the terminal receiving the corresponding MBS data is C- It may be at least one of RNTI, 5G-S-TMSI, I-RNTI, Subscription Concealed Identifier (SUCI)/Subscription Permarnent Identifier (SUPI), and 5G-GUTI.
  • the MBS context information may be classified using information for identifying the MBS session (e.g. MBS session information).
  • MBS context information may be allocated as information to be distinguished from information for identifying an MBS session.
  • the MBS context information may be associated with information for identifying an MBS session.
  • MBS context identification information may be allocated by a base station or one of UPF or AMF/SMF.
  • MBS context information is included in the handover preparation information message, it will be defined as a new information element distinct from the information element (eg AS-Config, AS-Contex) included in the conventional handover preparation information message.
  • the MBS context information may be included in an AS configuration information element or an AS context information element included in the conventional handover preparation information message.
  • One or more of the above-described information may be directly included in the handover request message as an information element, and other one or more pieces of information may be included in the handover preparation information message. That is, the above-described information may be divided and included in two or more messages.
  • the above-described embodiment may also be applied when moving from a multicast/broadcast transmission cell to a multicast/broadcast transmission cell.
  • a unicast session and an MBS session may be simultaneously established.
  • a unicast session and an MBS session may be simultaneously established.
  • the UE may receive the corresponding MBS data through a unicast session or an MBS session according to a network instruction.
  • the base station may transmit MBS data only through either a unicast session or an MBS session at a specific time.
  • the existing PDU session between the UE and the UPF may be used as it is or may be partially modified.
  • MBS data may be transmitted through a downlink PDU session.
  • the UE transmits the application layer request information or control information (eg IGMP, MLD, IP multicast address) necessary for receiving MBS data through the uplink PDU session (or through any user plane connection) to the UPF or for IP multicast reception. It can be transmitted to the base station.
  • the UPF or the base station can distinguish them.
  • the UPF may distinguish a corresponding packet through packet filtering.
  • the base station may distinguish a corresponding packet through an arbitrary uplink L2 control PDU (e.g.
  • the UPF or the base station can use it to change/modify the unicast session and the MBS session. For example, the detected information may be transmitted to the SMF/AMF/base station, or the UPF may instruct the UPF to select and transmit MBS data during a unicast session or an MBS session.
  • the UE transmits application layer request information necessary to receive MBS data through any uplink signaling (or any control plane connection) or control information (eg IGMP, MLD, IP multicast address) for IP multicast reception.
  • AMF/UPF or the base station can distinguish them.
  • AMF/SMF may receive corresponding information through NAS signaling.
  • the base station may receive the corresponding information through any uplink RRC message.
  • the AMF/SMF or the base station can use it to set/change/modify the unicast session and the MBS session.
  • the SMF/AMF may transmit detected information to the base station or may instruct the UPF to select and transmit MBS data during a unicast session or an MBS session.
  • the UPF may support first hop router function to support IP multicast transmission.
  • IGMP Internet Group Management Protocol, in the case of IPv4
  • MLD Multicast Listener Discovery, in the case of IPv6
  • the UPF may receive membership/join information for the MBS session of the terminal by detecting the IGMP packet.
  • membership/join information may be acquired in a multicast group.
  • leave information may be obtained from the multicast group.
  • the UPF may receive a report on membership/join/leave for a multicast session from the terminal by sending an IGMP Query message to the terminal.
  • the UPF may know that it has left the multicast group of the corresponding terminal.
  • the MBS session may be configured to have a unicast uplink session.
  • a unicast session may consist of a dedicated PDU session mapped one-to-one to an MBS session.
  • the unicast session may be configured as a dedicated PDU session mapped one-to-many/many-to-one to one or more MBS sessions.
  • the unicast session is performed under certain conditions (eg, when the terminal is interested in the MBS session, when the terminal transmits any uplink indication information/message for the MBS session to the base station or the network, when the terminal is receiving the MBS session ), it can be set and maintained without being released.
  • the condition may be applied to one terminal or may be applied specifically to a cell.
  • the radio bearer may be mapped one-to-many/many-to-one to one or more MBS sessions.
  • messages included in the PDU session establishment procedure are information for identifying the associated MBS session (MBS service ID, MBS session ID, TMGI).
  • session-ID e.g IP address for downlink tunnel between AMF and base station, GTP TEID
  • QoS flow information eg IP address for downlink tunnel between AMF and base station, GTP TEID
  • session/cast type multicast session, broadcast session, unicast
  • MBS session type information for distinguishing one or more of IPv4, IPv6, IPv4IPv6, ethernet, and unstructured
  • the MBS session may use the above-described MBS session start procedure (e.g. MBS session start request/response message).
  • MBS session start procedure e.g. MBS session start request/response message
  • the target base station prepares handover having an L1/L2 configuration.
  • the target base station may perform admission control on the received MBS session/MBS context.
  • the target base station transmits the MBS session requested by the source base station to the corresponding terminal in an arbitrary transmission method/cast type (eg multicast/broadcast (point-to-multipoint) transmission, unicast (point-to-point) transmission). You can decide whether to accept it or not.
  • the target base station may determine the transmission method/cast type (e.g. multicast/broadcast transmission, unicast transmission) for the corresponding MBS session requested by the source base station for the corresponding terminal.
  • the target base station may indicate to the source base station the transmission method/cast type for the corresponding MBS session requested by the source base station for the corresponding terminal.
  • the target base station may indicate to the source base station that multicast/broadcast transmission is being performed for the corresponding MBS session.
  • the source base station and the target base station transmit method/cast type (eg multicast/broadcast transmission, unicast transmission) for MBS sessions through the Xn interface message between the base stations, session start time, end time, cell identification information, etc. Information related to any MBS session can be exchanged.
  • the source base station and the target base station may request information between the base stations and receive a response, or may transmit the information to a neighboring base station according to a specific trigger condition.
  • the target base station may transmit the accepted MBS session resource information (MBS Session Resource Admitted List) to the source base station.
  • MBS Session Resource Admitted List MBS Session Resource Admitted List
  • the corresponding information may include at least one of MBS session identification information, MBS session context information, TNL information, accepted QoS flow information, and target base station data forwarding information (e.g. DL data forwarding GTP-TEID).
  • target base station data forwarding information e.g. DL data forwarding GTP-TEID.
  • the corresponding information may be transmitted from the target base station to the source base station through a HANDOVER REQUEST ACKNOWLEDGE message.
  • the source base station may transmit transmission method/cast type (e.g. multicast/broadcast transmission, unicast transmission) information for the corresponding MBS session to the target base station.
  • transmission method/cast type e.g. multicast/broadcast transmission, unicast transmission
  • the source base station may transmit configuration information for the corresponding MBS session to the target base station for the corresponding terminal.
  • the source base station may transmit unicast session information associated with the MBS session together to the target base station.
  • the target base station can configure DRB(s) according to the corresponding unicast session information.
  • the MBS data flow can be mapped and configured to the DRB(s) through the unicast target cell.
  • a service may be provided through DRB(s) for providing a unicast session associated with the corresponding MBS session by configuring a DRB according to the corresponding unicast session information in a target cell to be unicast handed over.
  • the source base station may propose/request data forwarding for each QoS flow of the corresponding MBS session through the aforementioned handover request message.
  • the target base station accepts data forwarding for at least one QoS flow for the MBS session, the target base station includes downlink TNL information for the QoS flow belonging to the corresponding MBS session through a HANDOVER REQUEST ACKNOWLEDGE message. can spend
  • packets of a QoS flow belonging to the corresponding MBS session may be forwarded through a DL (MBS radio bearer) forwarding tunnel mapped as RLC SDUs.
  • DL MBS radio bearer
  • the source base station may receive a GTP-U end marker for the corresponding MBS session from the UPF (or MBS UPF).
  • the source base station may transmit (replicate) the corresponding end marker through each data forwarding tunnel when no more data for the MBS session is forwarded through the tunnel. This can be performed by performing a procedure (described below) for the source base station to transmit a message for instructing/requesting modification/removal of a DL tunnel between the UPF and the base station associated with the MBS session with AMF/SMF.
  • a unidirectional UM mode RLC entity without PDCP may be used to perform multicast/broadcast data transmission on the radio interface between the base station and the terminal. Even when unicast transmission is performed for the MBS session, the SDAP entity may be directly linked to the RLC entity without PDCP.
  • the base station may instruct the terminal with configuration information for indicating this for data reception of the terminal.
  • a unidirectional UM mode RLC entity including PDCP may be used to perform multicast/broadcast data transmission on a radio interface between a base station and a terminal.
  • SDAP may be associated with a PDCP entity
  • a PDCP entity may be associated with an RLC entity.
  • Any fresh packets of the QoS flow belonging to the corresponding MBS session may be forwarded through a DL (MBS Radio Bearer) forwarding tunnel mapped as PDCP SDUs.
  • DL MMS Radio Bearer
  • An embodiment of transmitting radio bearer configuration information mapped for the corresponding MBS session to the terminal through the target base country RRC dedicated message (e.g. RRC Reconfiguration message)
  • the target base station is a handover command (RRC Reconfiguration) inter-node RRC having an L1/L2 configuration including radio bearer configuration information mapped based on information received from the source base station for the MBS session, corresponding MBS session context information, etc. Generates a message and sends it to the source base station.
  • the source base station instructs the RRC reconfiguration (RRC Reconfiguration) message to the terminal.
  • the MBMS receiving terminal received information on the MBMS service through system information and/or MCCH information.
  • the target base station that transmits multicast/broadcast for the corresponding MBS session is a UM without PDCP Handover can be performed using all RLC entities. Since there is no PDCP entity, reset of PDCP SN or SFN or retransmission of PDCP SDUs is not required in the target base station.
  • the unicast radio bearer for the MBS session at the source base station that unicasts MBS data uses a UM mode RLC entity without PDCP.
  • a target base station that transmits unicast for a session may perform handover using a UM mode RLC entity without PDCP. Since there is no PDCP entity, reset of PDCP SN or SFN or retransmission of PDCP SDUs is not required in the target base station.
  • radio bearer configuration information for an MBS session being transmitted by the target base station may be indicated to the terminal.
  • the target base station includes radio bearer configuration information for the corresponding MBS session in an RRC dedicated message (e.g. RRC Reconfiguration message) and transmits it to the terminal.
  • RRC dedicated message e.g. RRC Reconfiguration message
  • the radio bearer configuration information may be transmitted to the terminal through the source base station.
  • the UE may maintain/reconfigure the RLC entity to receive the RLC SDUs forwarded from the source base station to the target base station.
  • the UE may cancel/modify/reset it.
  • RLC SDUs may contain end markers. This may be transmitted through an RLC control PDU. Alternatively, it may be transmitted as an RLC data PDU including a header of a specific format. Alternatively, it may be transmitted as any L2/L3 user plane data (e.g. RLC SDU) including a header of a specific format. Alternatively, it may be transmitted as any L2/L3 control plane data including a header of a specific format.
  • the UE may reconfigure the RLC entity to receive RLC SDUs forwarded from the target base station.
  • the target base station may transmit/retransmit all downlink data forwarded by the source base station.
  • the RLC sequence number uses the MBS. It may be maintained per radio bearer (unicast radio bearer and/or MBS radio bearer) for The source base station may inform the target base station about the next DL RLC SN to be assigned to a packet that does not have an RLC SN yet.
  • the handover request message may include corresponding notification information.
  • the target base station that transmits multicast/broadcast for the corresponding MBS session uses PDCP. Handover can be performed using the included UM mode RLC entity.
  • the target base station resets the PDCP SN or SFN. Retransmissions for PDCP SDUs are not required.
  • the unicast radio bearer for the corresponding MBS session in the source base station that unicast transmits MBS data uses a UM mode RLC entity including PDCP.
  • a target base station transmitting unicast for the MBS session may perform handover using a UM mode RLC entity including PDCP.
  • the target base station resets the PDCP SN or SFN. Retransmissions for PDCP SDUs are not required.
  • the radio bearer configuration information for the MBS session in which the target base station is performing transmission may be indicated to the terminal.
  • the target base station includes radio bearer configuration information for the corresponding MBS session in an RRC dedicated message (e.g. RRC Reconfiguration message) and transmits it to the terminal.
  • RRC dedicated message e.g. RRC Reconfiguration message
  • the radio bearer configuration information may be indicated to the terminal through the target base station.
  • the UE may maintain/reconfigure the PDCP entity to receive PDCP SDUs forwarded from the source base station to the target base station. Upon completion of reception of the forwarded PDCP SDUs, the UE may cancel/modify/reset them.
  • PDCP SDUs may contain end markers. This may be transmitted through a PDCP control PDU. Alternatively, it may be transmitted as a PDCP data PDU including a header of a specific format. Alternatively, it may be transmitted as any L2/L3 user plane data (e.g. PDCP SDU) including a header of a specific format. Alternatively, it may be transmitted as any L2/L3 control plane data including a header of a specific format.
  • the terminal may reconfigure the PDCP entity to receive PDCP SDUs forwarded from the target base station.
  • the target base station may transmit/retransmit all downlink data forwarded by the source base station.
  • PDCP SN Sequence Number
  • MBS Radio Bearer
  • the source base station may inform the target base station about the next DL RLC SN to be assigned to a packet that does not have a PDCP SN yet. For example, the notification may be transmitted while being included in the handover request message. As another example, the corresponding notification may be transmitted while being included in the SN STATUS message.
  • the target base station that transmits multicast/broadcast for the corresponding MBS session may perform handover using the AM mode RLC entity including PDCP.
  • the target base station may maintain/reconfigure the PDCP entity to receive PDCP SDUs forwarded from the source base station in order or without loss.
  • the corresponding A target base station transmitting unicast for the MBS session may perform handover using an AM mode RLC entity including PDCP.
  • the radio bearer configuration information for the MBS session in which the target base station is transmitting may be indicated to the terminal.
  • the target base station includes radio bearer configuration information for the corresponding MBS session in an RRC dedicated message (e.g. RRC Reconfiguration message) and transmits it to the terminal.
  • the radio bearer configuration information may be indicated to the terminal through the source base station.
  • the UE may maintain/reconfigure the PDCP entity to receive PDCP SDUs forwarded from the source base station to the target base station. and/or the terminal may reconfigure the PDCP entity to receive PDCP SDUs forwarded from the target base station.
  • PDCP SN Sequence Number
  • MBS Mobile Broadcast Service Set
  • the source base station may inform the target base station about the next DL RLC SN to be assigned to a packet that does not have a PDCP SN yet.
  • the source base station may transmit a corresponding notification in a handover request message.
  • the corresponding notification may be transmitted while being included in the SN STATUS message.
  • the target base station may transmit/retransmit all downlink data forwarded by the source base station.
  • the target base station retransmits all downlink PDCP SDUs, starting from the oldest PDCP SDU not verified by RLC in the source base station.
  • the source base station may transmit the unconfirmed SN to the target base station.
  • An embodiment of adding/modifying instruction/requesting DL tunnel between the UPF and the base station connected to the MBS session from the target base station to the core network entity e.g. AMF/SMF
  • the UE synchronizes to the target cell and completes the RRC handover procedure by transmitting an RRCReconfigurationComplete message to the target base station.
  • the target base station If the target base station does not establish a DL tunnel between the UPF (or MBS UPF) associated with the MBS session and the target base station, or if the target base station does not receive data for the corresponding MBS session, the target base station It is necessary to request session start/initiation for the MBS session.
  • the target base station needs to transmit information for instructing/requesting to create/change/switch a tunnel between the UPF and the base station for the MBS session through an arbitrary 5G core network control plane entity (e.g. AMF/SMF). As an example, this may be provided by including the corresponding information in the conventional PATH SWITCH request message and transmitting it.
  • AMF/SMF 5G core network control plane entity
  • this may be transmitted through a message between the base station and the AMF/SMF interface that is distinct from the PATH SWITCH request message.
  • the message between the base station and the AMF/SMF interface may include one or more of the information exemplified in any of the above-described embodiments, such as MBS session information/MBS session context information, and a cast type.
  • the target base station does not need to transmit information for releasing it to the source base station.
  • the terminal context release message may include one or more pieces of information among the information exemplified in certain embodiments of the present invention, such as MBS session information/MBS session context information, and a cast type.
  • the target base station may identify the corresponding MBS session through the MBS session information/MBS context information received from the source base station.
  • the target base station may add/modify/store DL tunnel information between the UPF and the base station to the MBS context information for the corresponding terminal.
  • the target base station may add/modify/store related information to the corresponding terminal in the MBS context information.
  • the target base station may transmit information for instructing the source base station to release/modify/change the DL tunnel between the UPF and the base station.
  • the source base station may transmit information for instructing to release/modify/change the DL tunnel between the UPF and the base station to the AMF/SMF.
  • the source base station may transmit a unicast session (e.g.
  • the AMF/SMF may perform the session modification procedure by sending a unicast session (e.g. PDU session) modification request message related to the MBS session to the base station.
  • a unicast session e.g. PDU session
  • the UE may send join/join/leave information for the corresponding MBS session to one or more entities of the base station/AMF/SMF/UPF at the specific time point of the aforementioned cell change.
  • the transmission method of another embodiment described in this specification may be applied.
  • FIG. 12 is a diagram illustrating a downlink layer 2 structure in an LTE system.
  • MBMS Point to Multipoint Radio Bearer (MRB) or SC-MRB for providing MBMS in conventional LTE is data transmitted based on RLC-UM that provides a segmentation function without a PDCP entity.
  • the LTE base station was able to distinguish the payload/data belonging to the MBMS session through the MBMS session and Transport Network Layer (TNL) information transmitted through the MBMS session start request message.
  • TNL Transport Network Layer
  • the information on the MBMS session may include information about one or more of TMGI, MBMS session-ID, and MBMS service area.
  • the MBMS service area information includes an MBMS service area identifier (MBMS Service Area Identity (SAI)).
  • SAI MBMS Service Area Identity
  • MBMS SAI consists of 2 octets and is coded and used to identify a group of cells in one PLMN. And it is independent of physical cell and location area/routing area. One cell may belong to one or more MBMS service areas. Thus, it may be addressed by one or more MBMS service area identities (SAIs).
  • SAIs MBMS service area identities
  • the TNL information may include at least one of an IP multicast address, an IP source address, and a GTP DL TEID.
  • the LTE base station classifies data belonging to the MBMS session through TNL information and transmits the data in association with the corresponding MBMS radio bearer (or RLC-UM entity).
  • an MBS session In order to transmit MBS data (e.g. media, video, software downloading etc.), an MBS session must be established between the terminal and the core network entity.
  • MBS data e.g. media, video, software downloading etc.
  • the MBS session start request message transmitted by the core network control plane entity (e.g. AMF) to the base station may include QoS flow setup request information in addition to the MBS session and TNL (Transport Network Layer) information.
  • AMF Core Network Control plane entity
  • the base station may receive a session start request message for a specific MBS session through any core network control plane entity (eg, AMF).
  • AMF core network control plane entity
  • the corresponding message is identified as identification information for the corresponding MBS service (or MBS session) (for convenience of description, below, the identification information for the MBS session is indicated.
  • MBS service ID, MBS session ID , TMGI, session-ID, source specific IP multicast address, etc. may be replaced with any similar existing identification information or new term.
  • QoS information for the corresponding MBS session eg 5QI/QCI, QoS flow Identifier, GBR QoS flow
  • QoS information for the corresponding MBS session eg 5QI/QCI, QoS flow Identifier, GBR QoS flow
  • GBR QoS flow at least one of Maximum Flow Bit Rate, Guaranteed Flow Bit Rate, Maximum Packet Loss Rate), Allocation and Retention Priority, Priority Level Packet Delay Budget, and Packet Error Rate.
  • UE-AMBR Access Maximum Bit Rate
  • PDU Session AMBR PDU Session AMBR
  • Session-AMBR aggregate Maximum Bit Rate
  • Session-AMBR aggregate Maximum Bit Rate
  • the base station set to the sum of the Session-AMBR of all PDU sessions having the active user plane up to the UE-AMBR value received from the AMF (Each (R)AN shall set its UE-AMBR to the sum of the Session-AMBR of all PDU Sessions with active user plane to this (R)AN up to the value of the received UE-AMBR from AMF).
  • UE-AMBR and Session-AMBR were applied in both directions (uplink and downlink directions). And Session-AMBR was not applied to GBR QoS flow.
  • Session-AMBR enforcement (refer to 3GPP TS 23.501) was performed in UPF.
  • Session-AMBR execution was performed in the UE and UPF.
  • the operator may newly define information for limiting the maximum transfer rate of the MBS session and signal it.
  • the MBS session may be provided as a GBR QoS flow.
  • the MBS session may be provided as a non-GBR QoS flow.
  • the operator may define and signal aggregate rate limit QoS parameters per session for the MBS session.
  • the operator may define and signal an aggregate rate limit QoS parameter (e.g. UE-MBS_Seesions-AMBR) of the MBS session for each UE for the MBS session.
  • the aggregate rate limit QoS parameter of the MBS session for each UE may be set to a value equal to or smaller than that of the UE-AMBR.
  • the above parameters may be applied only to the downlink direction.
  • UE-AMBR may be set to the sum of Session-AMBR of all (unicast) PDU sessions having an active user plane except for the MBS session.
  • the UE-AMBR may be set to the sum of the Session-AMBR of all (unicast/multicast/broadcast) sessions having an active user plane, including the MBS session.
  • the above-mentioned parameters may be signaled from AMF/SMF/MB-SMF to a base station, or from AMF/SMF/MB-SMF to a terminal, or from AMF/SMF/MB-SMF to UPF.
  • the signaling message is a signaling message according to a known standard (eg PDU Session Establishment Request between the base station and AMF between the terminal and AMF, PDU SESSION RESOURCE SETUP REQUEST, PDU SESSION RESOURCE SETUP RESPONSE, Nsmf_PDUSession_CreateSMContex Request between AMF and SMF, Smf_PDUSession_CreateSMContex Request, NsmContf_PDUSession_CreateSMContex It may mean any PDU session establishment procedure related message such as Session Establishment/Modification Request and Session Establishment/Modification Response between MB-SMF and UPF/MB-UFP).
  • a known standard eg PDU Session Establishment Request between the base station and AMF between the terminal and AMF, PDU SESSION RESOURCE SETUP REQUEST, PDU SESSION RESOURCE SETUP RESPONSE, Nsmf_PDUS
  • NR is required to support MBS in various vertical domains.
  • MBS Mobility Management Function
  • MBS session it may be desired to provide file transmission for software upgrade for a specific IoT terminal group through an MBS session.
  • the MBS session start request message received by the base station may include information about one or more of MBS session start time, MBS session stop time, MBS session duration, MBS session repetition number, and MBS session repetition period.
  • the MBS session start time may indicate a time at which MBS data is transmitted in the base station/network through the MBS radio bearer.
  • the MBS session stop time may indicate a time when MBS transmission is expected to be completed.
  • the duration of the MBS session may indicate a transmission period of MBS data.
  • the number of MBS session repetitions may indicate the number of times MBS data transmission is repeated, and the MBS session repetition period may indicate a cycle at which MBS data transmission is repeated. If that information is not included, the MBS data is transmitted immediately or is expected to be transmitted immediately. And it is stopped or expected to be stopped by a message instructing to stop the corresponding session.
  • the base station may calculate/convert the received information into scheduling information for MBS data transmission by the base station using or based on the received information.
  • the base station may transmit the corresponding information through system information or logical channel information (e.g. MCCH, SC-MCCH, MBS-MCCH) for MBS transmission.
  • system information e.g. MCCH, SC-MCCH, MBS-MCCH
  • the corresponding time information may be indicated by being linked/mapped/converted to Coordinated Universal Time (UTC) by the base station through system information (e.g. SIB9).
  • the time information may be indicated through offset time information with UTC time information (timeInfoUTC) corresponding to the SFN boundary or immediately after the end boundary of the SI-window through which SIB9 is transmitted.
  • timeInfoUTC UTC time information
  • the corresponding time information may be indicated by being linked/mapped/converted to the SFN.
  • the start SFN, the repeating start SFN list, the start offset/frame/slot/subframe/time point, duration/duration/length, repetition period, and number of repetitions may be indicated through one or more of information.
  • the UE may acquire scheduling information through which MBS data is transmitted in units of PDCCH slots.
  • scheduling information for instructing to discontinuously perform PDCCH monitoring for a corresponding specific RNTI may be indicated.
  • the corresponding scheduling information may include one or more of an on-duration timer, an inactivity timer, a scheduling period, and a scheduling offset as a parameter for DRX reception.
  • the cell identification information to provide the MBS service area may be directly included in the MBS session start request message.
  • Conventional MBMS coded e.g. SAI
  • SAI a designated service area and requested session start including corresponding code (SAI) information.
  • SAI corresponding code
  • the MBS session start request message may include cell information/cell list information through which the corresponding base station will transmit MBS data.
  • Corresponding cell / cell list information includes at least one of physical cell identifier information, NR CGI (Cell Global Identifier: used to globally identify an NR cell), E-UTRA CGI, gNB ID, PLMN Identity, and NCI (NR Cell Identity) information can do.
  • NR CGI Cell Global Identifier: used to globally identify an NR cell
  • E-UTRA CGI E-UTRA CGI
  • gNB ID gNB ID
  • PLMN Identity PLMN Identity
  • NCI NR Cell Identity
  • the MBS session start request message contains information for distinguishing the type (or cast type) of the MBS session (or 1-bit information for distinguishing the cast type eg Multicast/Broadcast or 2 for distinguishing Multicast/Broadcast/Unicast bit information) or information for indicating the type of MBS session.
  • the base station can perform appropriate MBS transmission in the wireless network by considering/classifying the MBS session type.
  • the MBS session start request message may include information on the number of terminals expected/expected to join (receive MBS) to the corresponding MBS session.
  • the response message to the MBS session start request message may include information on the number of terminals that have actually joined (MBS received) the corresponding MBS session to the corresponding base station.
  • the base station can perform appropriate MBS transmission in the wireless network by considering/classifying the MBS session type.
  • the MBS session may be transmitted in association with an MBS (point-to-multipoint) radio bearer.
  • the MBS session may be transmitted in association with a unicast (point-to-point) radio bearer (DRB).
  • the core network entity e.g. one of AMF, SMF, UPF, and MBS Function
  • IGMP Internet Group Management Protocol, in the case of IPv4
  • MLD Multicast Listener Discovery, in the case of IPv6
  • An MBS session may be established between the UE and the UPF.
  • the UPF must be able to receive the configuration information for the MBS session from the AMF/SMF.
  • the UPF may transmit the corresponding MBS flow to the base station through packet filtering for the MBS flow.
  • UPF may support first hop router function to support IP multicast transmission.
  • the UPF may receive membership/join information for the MBS session of the terminal by detecting the IGMP packet.
  • membership/join information may be acquired in a multicast group.
  • leave information may be obtained from the multicast group.
  • the UPF may receive a report on membership/join/leave for a multicast session from the terminal by sending an IGMP Query message to the terminal.
  • IGMP Query message if there is no periodically received IGMP report, it can be known that the UPF has left the multicast group of the corresponding terminal. As an example for this, it is possible to have a unicast uplink session associated with the MBS session.
  • a PDU session for an MBS session may be configured between the UE and the UPF. This may be provided through a normal PDU session establishment procedure.
  • Messages included in the PDU session establishment procedure may include one or more information.
  • PDU Session Establishment Request between terminal and AMF PDU SESSION RESOURCE SETUP REQUEST between base station and AMF
  • PDU SESSION RESOURCE SETUP RESPONSE Nsmf_PDUSession_CreateSMContex Request between AMF and SMF
  • Nsmf_PDUSession_CreateSMContex Response Nsmf_PDUSession_CreateSMContex Response
  • MBS service ID MBS session ID, TMGI, session-ID, IP multicast address
  • TNL information QoS flow information
  • session type information for distinguishing one or more of a multicast session, a broadcast session, and a PDU session
  • session type information for distinguishing one or more of a multicast session, a broadcast session, and a PDU session
  • the corresponding PDU session may be configured by simultaneously connecting one to the unicast PDU session and the other to the MBS session.
  • MBS data can be individually transmitted from the 5G core network to the terminal through the unicast PDU session associated with the MBS session.
  • Information for joining the multicast group of the MBS session may be transmitted through the unicast PDU session associated with the MBS session.
  • the UE may transmit a PDU session setup/modification request message in order to join the MBS multicast group and receive data for the corresponding MBS session.
  • the UE may transmit an IGMP message/packet for joining a multicast group through a data radio bearer mapped to a PDU session associated with the MBS session.
  • one MBMS session is mapped to one MBMS Point to Multipoint Radio Bearer (MRB)/Single Cell MRB (SC-MRB).
  • MRB Point to Multipoint Radio Bearer
  • SC-MRB Single Cell MRB
  • the UE sets one RLC entity according to the default configuration, and MTCH logical channel according to the logical channel identification information (logicalChannelIdentity) included in the MCCH (MBSFNAreaConfiguration) message. to constitute one MRB.
  • logicalChannelIdentity logical Channel identification information included in the MCCH (MBSFNAreaConfiguration) message.
  • SC-MRB when configuring SC-MRB to start one MBMS session, the UE configures one RLC entity according to the default configuration, and includes g-RNTI and scheduling information ( sc-mtch-SchedulingInfo), one SC-MRB was configured. Accordingly, SC-MCCH or SC-MTCH is fixed to one designated logical channel identifier (LCID 11001).
  • NR provides flow-based QoS. Therefore, when applying the MBS session in NR, it is desirable to provide flow unit classification processing.
  • one MBS session may include one or more QoS flows having different QoS characteristics.
  • the base station may associate the aforementioned identification information for the MBS session and one or more QoS flows mapped to the corresponding MBS session to one or more radio bearers.
  • a radio bearer associated with an MBS session is denoted as an MBS radio bearer.
  • MBS radio bearer it is assumed that one MBS session has three different flows (QFI1, QFI2, QFI2) and is associated with two MBS radio bearers (MBS-RB1, MBS-RB2).
  • a QoS flow may be mapped to an MBS radio bearer by configuring one Service Data Adaptation Protocol (SDAP) entity for each MBS session.
  • SDAP Service Data Adaptation Protocol
  • FIG. 13 is a diagram exemplarily illustrating MBS radio bearer configuration information according to an embodiment.
  • MBS session configuration information for instructing to map QFI1 and QF2 to MBS-RB1 and QF3 to MBS-RB2 is shown.
  • the MBS-RB is configured without a PDCP entity
  • the PDCP-Config included in the MBS-RB configuration information in FIG. 13 may be deleted.
  • PDCP-Config included in MBS-RB configuration information in FIG. 13 may be deleted and RLC-BearerConfig may be included.
  • it can be configured by defining a mode for transparently transmitting PDCP.
  • the corresponding mode may be transmitted without including the PDCP header.
  • PDCP functions e.g. ROHC, Security
  • it may include information for instructing to enable/disable the corresponding function.
  • FIG. 14 is a diagram exemplarily illustrating MBS radio bearer configuration information according to another embodiment.
  • one SDAP Service Data Adaptation Protocol
  • QoS flows can be mapped to MBS radio bearers. Since the MBS session can be configured specifically for a cell, one SDAP can be configured and provided for all MBS sessions. Accordingly, MBS session configuration information for instructing to map QFI1 and QF2 to MBS-RB1 and QFI3 to MBS-RB2 may be configured as shown in FIG. 14 .
  • the terminal may designate and use a specific RNTI (e.g. M-RNTI, SC-RNTI, G-RNTI of conventional LTE technology) for MBS data reception
  • a specific RNTI e.g. M-RNTI, SC-RNTI, G-RNTI of conventional LTE technology
  • an RNTI capable of receiving data by multiplexing a plurality of MBS sessions may be used. If an RNTI capable of receiving data by multiplexing a plurality of MBS sessions (eg, one cell-specific RNTI for the entire service similar to M-RNTI) is used, one or more QoS flows belonging to different MBS sessions are the same It may be mapped and transmitted to one radio bearer having QoS characteristics. One radio bearer having the same QoS characteristics may be associated with one or more MBS sessions. For example, PDCP entity/RLC entity/logical channel identification information may be associated with one or more MBS session information. For example, through MBS session identification information and QFI (information for identifying a QoS flow within one MBS session), the UE can classify and process the MBS session.
  • MBS session identification information and QFI information for identifying a QoS flow within one MBS session
  • the UE may use an RNTI (eg, a session-specific RNTI similar to SC-RNTI and G-RNTI) capable of receiving data by being classified for each MBS session.
  • an RNTI eg SC-RNTI, similar to G-RNTI
  • one or more QoS flows belonging to different MBS sessions may have the same QoS characteristics even if they have the same QoS characteristics. It cannot be transmitted because it is mapped to a bearer.
  • One or more QoS flows belonging to one MBS session may be mapped and transmitted to one radio bearer having the same QoS characteristics.
  • One or more QoS flows belonging to one MBS session may be mapped and transmitted to respective radio bearers having different QoS characteristics.
  • PDCP entity/RLC entity/logical channel identification information may be associated with one MBS session information.
  • the UE distinguishes and processes the MBS session through the association information between SDAP configuration information (eg QFI (information for identifying QoS flows within one MBS session)) and PDCP entity/RLC entity/logical channel identification information.
  • MBS radio bearer identification information/RLC radio bearer/logical channel identification information associated with each QoS flow associated with each MBS session may be indicated from the base station to the terminal.
  • a control logical channel (eg MBS Control Channel) and/or a traffic logical channel (eg MBS Traffic Channel) included in the same MBS session may be multiplexed with other logical channels included in the same MBS session within the same MAC PDU.
  • a control logical channel (e.g. MBS Control Channel) and/or a traffic logical channel (e.g. MBS Traffic Channel) included in the same MBS session may be multiplexed with other logical channels within the same MAC PDU.
  • a control logical channel (eg MBS Control Channel) and/or a traffic logical channel (eg MBS Traffic Channel) included in the same MBS session is a control logical channel (eg MBS Control) included in different MBS sessions within the same MAC PDU.
  • Channel eg MBS Traffic Channels
  • 15 is a diagram illustrating a layer 2 structure according to an exemplary embodiment.
  • data may be processed by including one multiplexing entity for two MBS sessions (or all MBS sessions) without including each multiplexing entity for each MBS session.
  • 16 is a diagram illustrating an example of a layer 2 structure for NR MBS data transmission/reception.
  • a radio bearer structure for one MBS service session may be defined as a split bearer structure having two legs/paths.
  • service interruption is minimized and switching can be performed quickly.
  • switching between unicast transmission and multicast transmission may be performed without a separate switching instruction.
  • lossless transmission can be easily provided when switching between a general radio bearer and an MBR using a SPLIT bearer structure.
  • service interruption is minimized and switching can be performed quickly.
  • the unicast transmission type of the present invention indicates unicast using a general data radio bearer structure
  • the multicast or broadcast transmission type indicates multicast or broadcast using MRB based on the SPLIT bearer structure.
  • one leg/path of the MBS radio bearer based on the SPLIT bearer structure includes the L2 entity(s) configuration by unicast DRB, and the other leg/path ) may be configured to include the L2 entity(s) configuration by the MRB.
  • a unicast DRB leg RLC entity may be configured in association with a logical channel identifier. and/or the MAC may receive data by scheduling indicated by the C-RNTI.
  • the MRB leg RLC entity is an RNTI (eg SC-RNTI, G) for identifying transmission of RNTI or MBS session data (for convenience of description, MBS user data is denoted as NR-MTCH) that can receive data by dividing by MBS session - Similar to RNTI, it can be configured in association with a session-specific RNTI).
  • the unicast leg DRB RLC entity and the MRB leg RLC entity may be associated with one PDCP entity.
  • the PDCP entity may be associated with an MBS service session (TMGI and optionally session ID (sessionId), IP multicast address).
  • the terminal may receive the MBS service data transmitted according to the transmission method selected by the base station. For this, RRC signaling may be used. Alternatively, L2 signaling may be used. Alternatively, user data may be received and processed without signaling.
  • the transmission efficiency of the MBS session delivery increases.
  • transmission efficiency is reduced.
  • the MBS session is intended to support data reception by multiple users, and radio transmission efficiency is inevitably lower than that of unicast-based transmission. Therefore, if the network can dynamically switch/change unicast transmission and multicast/broadcast transmission for one MBS data, the efficiency of wireless transmission can be increased.
  • a unicast session and an MBS session may be dually configured.
  • a unicast session and an MBS session can be established at the same time.
  • the UE may receive the corresponding MBS data through a unicast session or an MBS session according to a network instruction.
  • the base station may transmit MBS data only through either a unicast session or an MBS session at a specific time.
  • the existing PDU session between the UE and the UPF may be used as it is or may be partially modified.
  • MBS data may be transmitted through a downlink PDU session.
  • the UE needs application layer request information (eg, information for joining MBS multicast group) or control information for IP multicast reception required to receive MBS data through an uplink PDU session (or through any user plane connection) eg IGMP, MLD, IP multicast address) can be transmitted to UPF or base station.
  • application layer request information eg, information for joining MBS multicast group
  • IGMP IGMP
  • MLD IP multicast address
  • the base station may distinguish a corresponding packet through an arbitrary uplink L2 control PDU (e.g. MAC CE, RLC control PDU, PDCP control PDU, SDAP control PDU).
  • an arbitrary uplink L2 control PDU e.g. MAC CE, RLC control PDU, PDCP control PDU, SDAP control PDU.
  • the UPF or the base station can use it to change/modify the unicast session and the MBS session.
  • the detected information may be transmitted to the SMF/AMF/base station, or the UPF may instruct the UPF to select and transmit MBS data during a unicast session or an MBS session.
  • the UE may receive application layer request information (eg, information for joining an MBS multicast group) or control information for IP multicast reception required to receive MBS data through any uplink signaling (or any control plane connection). eg IGMP, MLD, IP multicast address) can be transmitted.
  • the AMF/UPF or the base station can distinguish them.
  • AMF/SMF may receive corresponding information through NAS signaling.
  • the base station may receive the corresponding information through any uplink RRC message.
  • the AMF/SMF or the base station can use it to change/modify the unicast session and the MBS session.
  • the SMF/AMF may transmit detected information to the base station or may instruct the UPF to select and transmit MBS data during a unicast session or an MBS session.
  • UPF can be made to support first hop router function to support IP multicast transmission.
  • IGMP Internet Group Management Protocol, in the case of IPv4
  • MLD Multicast Listener Discovery, in the case of IPv6
  • IGMP Internet Group Management Protocol
  • MLD Multicast Listener Discovery, in the case of IPv6
  • the UPF may receive membership/join information for the MBS session of the terminal by detecting the IGMP packet.
  • membership/join information may be acquired in a multicast group.
  • leave information may be obtained from the multicast group.
  • the UPF may transmit an IGMP Query message to the terminal to receive a report on membership/join/leave for the multicast session from the terminal.
  • IGMP report it can be known that the UPF has left the multicast group of the corresponding terminal.
  • the MBS session may have a unicast uplink session.
  • a unicast session may consist of a dedicated PDU session mapped one-to-one to an MBS session.
  • the unicast session may be configured as a dedicated PDU session mapped one-to-many to one or more MBS sessions.
  • the unicast session is performed under certain conditions (eg, when the terminal is interested in the MBS session, when the terminal transmits any uplink indication information/message for the MBS session to the base station or the network, when the terminal is receiving the MBS session ), it can be set and maintained without being released.
  • messages included in the PDU session establishment procedure (eg, PDU Session Establishment Request between the terminal and AMF, PDU SESSION RESOURCE SETUP REQUEST between the base station and AMF, PDU SESSION RESOURCE SETUP RESPONSE, between AMF and SMF Nsmf_PDUSession_CreateSMContex Request, Nsmf_PDUSession_CreateSMContex Request, Nsmf_PDUSession_CreateSMContex Request) Information (MBS service ID, MBS session ID, TMGI, session-ID), TNL information (eg IP address for downlink tunnel between AMF and base station, GTP TEID), QoS flow information, session/cast type (one or more of multicast session, broadcast session, unicast session) It may include at least one of information) and MBS session type (information for distinguishing one or more of IPv4, IPv6, IPv4IPv6, ethernet, and unstructured) information.
  • one unicast session may be modified/changed/switched into one MBS session according to a request of a base station/network/terminal.
  • one MBS session may be modified/changed/switched into one unicast session according to the request of the base station/network/terminal.
  • modification/change/switching between sessions is performed, the previous session may be released and a new session may be established.
  • a new session may be established first and then the previous session may be released.
  • the base station/network/terminal may initiate a procedure for releasing the previous session.
  • An MBS session between the UPF and the base station may have one or more QoS flows.
  • Each corresponding flow or one flow may have associated UP Transport layer information. This is information on the downlink tunnel between the UPF and the base station, and may include the base station's IP address and GTP-TEID.
  • the base station maps the corresponding QoS flow identification information to the MBS radio bearer and transmits data. In this case, the base station may select unicast transmission or MBS transmission according to the determination of the base station or information determined and indicated by the core network entity.
  • the network determines unicast transmission to transmit data through a unicast session and when MBS transmission determines and transmits data through MBS session, different tunnels between the UPF and the base station Using , can be a significant overhead. Therefore, even when data is transmitted through a unicast session, it is desirable to transmit data by sharing a tunnel ( downlink tunnel between UPF and base station or between MBS user plane function and base station) transmitted to the base station through the MBS session. . Accordingly, one or more terminals can share and use a tunnel (a downlink tunnel between the UPF and the base station or a downlink tunnel between the MBS user plane function and the base station) transmitted to the base station through the MBS session.
  • any PDU session establishment procedure related messages such as Session Establishment/Modification Request and Session Establishment/Modification Response between SMF/MB-SMF and UPF/MB-UFP are information for identifying the associated MBS session (MBS service ID, MBS session ID, TMGI, session-ID, IP multicast address), TNL information of shared tunnel
  • one unicast session may be modified/changed/switched into one MBS session according to a request of a base station/network/terminal.
  • one MBS session may be modified/changed/switched into one unicast session according to the request of the base station/network/terminal.
  • modification/change/switching between sessions is performed, the previous session may be released and a new session may be established.
  • a new session may be established first and then the previous session may be released.
  • the base station/network/terminal may initiate a procedure for releasing the previous session.
  • An MBS session between the UPF and the base station may have one or more QoS flows.
  • Each corresponding flow may have associated UP Transport layer information. This is information on the downlink tunnel between the UPF and the base station, and may include the base station's IP address and GTP-TEID.
  • the base station maps the corresponding QoS flow identification information to the MBS radio bearer and transmits data. In this case, the base station may transmit MBS data by selecting unicast transmission or MBS transmission according to the determination of the base station or information determined and instructed by the core network entity.
  • indication information for sharing the N3 tunnel between the UPF of the MBS session and the base station may be included.
  • messages included in the PDU session establishment/modification procedure eg PDU Session Establishment Request between UE and AMF, PDU SESSION RESOURCE SETUP REQUEST between base station and AMF, PDU SESSION RESOURCE SETUP RESPONSE, Nsmf_PDUSession_CreateSMContex Request between AMF and SMF, Nsmf_PDUSession_CreateSMContex_PDUSession
  • Any PDU session establishment procedure related messages such as Response, Session Establishment/Modification Request, Session Establishment/Modification Response between SMF/MB-SMF and UPF/MB-UFP
  • MBS service ID MBS session ID
  • TMGI session-ID
  • IP multicast address IP multicast address
  • An MBS session may be established between the UE and the UPF.
  • the UPF must be able to receive the configuration information for the MBS session from the AMF/SMF.
  • the UPF may transmit the corresponding MBS flow to the base station through packet filtering for the MBS flow.
  • UPF may support first hop router function to support IP multicast transmission.
  • the UPF may receive membership/join information for the MBS session of the terminal by detecting the IGMP packet. As an example, it is possible to obtain membership/join information in a multicast group. As another example, information about leaving a multicast group may be obtained.
  • the UPF may receive a report on membership/join/leave for a multicast session from the terminal by sending an IGMP Query message to the terminal.
  • the UPF may know that it has left the multicast group of the corresponding terminal.
  • the MBS session may have a unicast uplink session.
  • a PDU session for an MBS session (or a PDU session associated with an MBS session or a unicast PDU session associated with an MBS session) may be configured between the UE and the UPF. This may be provided through a normal PDU session establishment procedure.
  • Messages included in the PDU session establishment procedure may include one or more information.
  • PDU Session Establishment Request between the base station and the AMF between the UE and the AMF
  • PDU SESSION RESOURCE SETUP REQUEST PDU SESSION RESOURCE SETUP REQUEST
  • PDU SESSION RESOURCE SETUP RESPONSE between the AMF and SMF
  • Nsmf_PDUSession_CreateSMContex Request Nsmf_PDUSession_CreateSMContex Response
  • Nsmf_PDUSession_CreateSMContex Response Nsmf_PDUSession_CreateSMContex Response
  • Any PDU session establishment procedure related messages such as Session Establishment/Modification Request, Session Establishment/Modification Response, etc. between UPF/MB-UFP -ID), TNL information, QoS flow information, and session type (information for distinguishing one or more of a multicast session, a broadcast
  • one corresponding PDU session may be drawn in a unicast PDU session and the other may be configured in connection with an MBS session at the same time.
  • MBS data can be individually transmitted from the 5G core network to the terminal through the unicast PDU session associated with the MBS session.
  • Information for joining the multicast group of the MBS session may be transmitted through the unicast PDU session associated with the MBS session.
  • the UE may transmit a PDU session setup/modification request message in order to join the MBS multicast group and receive data for the corresponding MBS session.
  • the UE may transmit an IGMP message/packet for joining a multicast group through a data radio bearer mapped to a PDU session associated with the MBS session.
  • the MBS session may support an Ethernet type MBS session or a PDU session.
  • the present embodiment provides the effect of receiving MBS data while minimizing service interruption even when the terminal receiving the MBS service in the wireless network moves.
  • 17 is a diagram illustrating a terminal configuration according to an embodiment.
  • a terminal 1700 receiving MBS (Multicast/Broadcast Service) data receives MBS data through an MBS radio bearer mapped to an MBS session in a source cell 1730 and a target in the source cell.
  • a control unit 1710 for triggering a cell change to a cell may be included.
  • the receiver 1730 may further receive MBS data through one of an MBS radio bearer mapped to an MBS session in the target cell or a radio bearer mapped to a PDU session associated with the MBS session.
  • the terminal 1700 may receive multicast/broadcast service data of interest from a specific cell or base station.
  • the receiver 1730 may receive MBS data through a radio bearer mapped to an MBS session.
  • the receiver 1730 may receive MBS data mapped to a PDU session associated with the MBS session. That is, the receiver 1730 may receive MBS data through a multicast/broadcast radio bearer or through a unicast radio bearer.
  • a situation such as a cell change or a base station change may occur according to the movement of the terminal.
  • the base station may determine and instruct the handover of the terminal.
  • the base station may instruct a cell change according to the movement of the terminal.
  • the terminal may change a cell or a base station for any reason.
  • the control unit 1710 may perform a cell change operation from the source cell to the target cell according to the instruction of the base station.
  • the source cell and the target cell may be cells controlled by the same base station or cells controlled by different base stations.
  • the UE When the control unit 1710 performs a cell change to the target cell, the UE needs to receive MBS data from the target cell as well.
  • the receiver 1730 may receive MBS data received from the source cell through the MBS radio bearer mapped to the MBS session of the target cell in the target cell.
  • the receiver 1730 may receive MBS data received from the source cell through a radio bearer (DRB) mapped to a PDU session connected to the MBS session of the target cell in the target cell.
  • DRB radio bearer
  • MBS data received through the MBS radio bearer mapped to the MBS session may be received using a Radio Network Temporary Identifier (RNTI) addressing the MBS session data.
  • RNTI Radio Network Temporary Identifier
  • MBS data received through a radio bearer mapped to a PDU session associated with the MBS session may be received using a Cell-Radio Network Temporary Identifier (C-RNTI).
  • C-RNTI Cell-Radio Network Temporary Identifier
  • the PDU session associated with the MBS session may be established or modified when the terminal initiates a procedure for joining the MBS session.
  • the transmitter 1720 transmits a PDU session establishment/modification request message to the core network entity through the base station.
  • the receiving unit 1730 receives the PDU session establishment/modification command message through the base station, and the control unit 1710 may set or modify the PDU session associated with the MBS session to the terminal.
  • Whether the terminal receives MBS data through the MBS radio bearer in the target cell or receives MBS data through the radio bearer mapped to the PDU session associated with the MBS session may be determined depending on whether the target cell supports MBS.
  • MBS data received from the target cell may be received through a radio bearer mapped to a PDU session associated with the MBS session.
  • the UE may receive MBS data through the MBS radio bearer.
  • MBS data can be seamlessly performed through the MBS radio bearer or the radio bearer mapped to the PDU session regardless of whether the changed cell is supported.
  • MBS data can be continuously received through the multicast/broadcast method.
  • MBS data can be continuously received regardless of cell change even in the same method (unicast to unicast, multicast/broadcast to multicast/broadcast).
  • controller 1710 controls the overall operation of the terminal 1700 according to the control so that the terminal necessary for performing the above-described embodiment continuously receives MBS data.
  • the transmitter 1720 and the receiver 1730 are used to transmit and receive signals, messages, and data necessary for performing the above-described embodiment with the base station and the core network entity.
  • FIG. 18 is a diagram illustrating a configuration of a base station according to an embodiment.
  • a base station 1800 that transmits MBS (Multicast/Broadcast Service) data determines a radio bearer for transmitting MBS data based on whether or not MBS is supported when a terminal receiving MBS data accesses according to a cell change. and a transmitter 1820 for transmitting MBS data through one of the MBS radio bearer mapped to the MBS session or the radio bearer mapped to the PDU session associated with the MBS session according to the determination.
  • MBS Multicast/Broadcast Service
  • the terminal may receive the multicast/broadcast service data of interest from the source cell or the base station.
  • the terminal may receive MBS data through a radio bearer mapped to the MBS session.
  • the terminal may receive MBS data mapped to a PDU session associated with the MBS session. That is, the UE may receive MBS data through a multicast/broadcast radio bearer or through a unicast radio bearer.
  • a situation such as a cell change or a base station change may occur according to the movement of the terminal.
  • the source base station may determine and instruct the handover of the terminal.
  • the base station may instruct a cell change according to the movement of the terminal.
  • the terminal may change a cell or a base station for any reason.
  • the control unit 1810 may determine a method for transmitting MBS data based on whether the corresponding base station supports MBS in order to provide continuity of MBS data reception of the terminal. Alternatively, the control unit 1810 may determine the transmission method of MBS data to be transmitted to the terminal according to the instruction of the core network entity.
  • the transmitter 1820 may transmit MBS data in a multicast/broadcast manner or may transmit MBS data in a unicast manner.
  • the transmitter 1820 may transmit MBS data through an MBS radio bearer mapped to an MBS session.
  • the transmitter 1820 may transmit MBS data through a radio bearer mapped to a PDU session associated with the MBS session.
  • MBS data transmitted through the MBS radio bearer mapped to the MBS session may be transmitted using a Radio Network Temporary Identifier (RNTI) addressing the MBS session data.
  • RNTI Radio Network Temporary Identifier
  • MBS data transmitted through a radio bearer mapped to a PDU session associated with the MBS session may be transmitted using a Cell-Radio Network Temporary Identifier (C-RNTI).
  • C-RNTI Cell-Radio Network Temporary Identifier
  • MBS data may be transmitted through a radio bearer mapped to a PDU session associated with the MBS session.
  • the MBS data may be transmitted through the MBS radio bearer mapped to the MBS session.
  • the MBS data transmission scheme may be determined in consideration of additional factors such as the number of MBS data receiving terminals in the cell, in addition to whether the base station is supported.
  • MBS data can be seamlessly performed through the MBS radio bearer or the radio bearer mapped to the PDU session regardless of whether the changed cell is supported.
  • the PDU session associated with the MBS session may be established or modified when the terminal initiates a procedure for joining the MBS session.
  • the transmitter 1820 receives the PDU session establishment/modification request message from the terminal and transmits it to the core network entity. Thereafter, the transmitter 1820 may transmit the PDU session setup/modification command message received from the core network entity to the terminal through the RRC message.
  • the terminal may receive the PDU session establishment/modification command message through the base station, and may set or modify the PDU session associated with the MBS session to the terminal.
  • controller 1810 controls the overall operation of the base station 1800 according to the base station necessary for performing the above-described embodiment to support continuous MBS data reception of the terminal.
  • the transmitter 1820 and the receiver 1830 are used to transmit and receive signals, messages, and data necessary for performing the above-described embodiment with the terminal and the core network entity.
  • the above-described embodiments may be implemented through various means.
  • the present embodiments may be implemented by hardware, firmware, software, or a combination thereof.
  • the method according to the present embodiments may include one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processors (DSPs), Digital Signal Processing Devices (DSPDs), Programmable Logic Devices (PLDs), FPGAs (Field Programmable Gate Arrays), may be implemented by a processor, a controller, a microcontroller or a microprocessor.
  • ASICs Application Specific Integrated Circuits
  • DSPs Digital Signal Processors
  • DSPDs Digital Signal Processing Devices
  • PLDs Programmable Logic Devices
  • FPGAs Field Programmable Gate Arrays
  • the method according to the present embodiments may be implemented in the form of an apparatus, procedure, or function that performs the functions or operations described above.
  • the software code may be stored in the memory unit and driven by the processor.
  • the memory unit may be located inside or outside the processor, and may transmit and receive data to and from the processor by various known means.
  • system generally refer to computer-related entities hardware, hardware and software. may mean a combination of, software, or running software.
  • the aforementioned components may be, but are not limited to, a process run by a processor, a processor, a controller, a controlling processor, an object, a thread of execution, a program, and/or a computer.
  • an application running on a controller or processor and a controller or processor can be a component.
  • One or more components may reside within a process and/or thread of execution, and components may be located on one device (eg, a system, computing device, etc.) or distributed across two or more devices.

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Abstract

La présente divulgation se rapporte à une technologie pour une opération de traitement de données de service de multidiffusion/diffusion (MBS). Un aspect de l'invention concerne un procédé de réception, par un terminal, de données de service de multidiffusion/diffusion (MBS), et un appareil, le procédé comprenant les étapes consistant à : recevoir des données de MBS par l'intermédiaire d'une porteuse radio de MBS mise en correspondance avec une session de MBS dans une cellule source ; déclencher un changement de cellule de la cellule source à une cellule cible ; et recevoir des données de MBS par l'intermédiaire d'une porteuse radio de MBS mise en correspondance avec une session de MBS dans la cellule cible et d'une porteuse radio mise en correspondance avec une session de PDU associée à la session de MBS.
PCT/KR2021/001435 2020-02-14 2021-02-03 Procédé de traitement de données de mbs et appareil associé WO2021162333A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
KR20200018407 2020-02-14
KR10-2020-0018407 2020-02-14
KR1020210014051A KR20210104563A (ko) 2020-02-14 2021-02-01 Mbs 데이터를 처리하는 방법 및 그 장치
KR10-2021-0014051 2021-02-01

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WO2021162333A1 true WO2021162333A1 (fr) 2021-08-19

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Cited By (3)

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Publication number Priority date Publication date Assignee Title
WO2023066188A1 (fr) * 2021-10-19 2023-04-27 夏普株式会社 Procédé de transfert intercellulaire de cellule et équipement utilisateur
WO2023069375A1 (fr) * 2021-10-21 2023-04-27 Google Llc Gestion de transmissions de diffusion individuelle, de multidiffusion et de diffusion
EP4346243A1 (fr) * 2022-09-30 2024-04-03 MediaTek Inc. Décodage d'informations d'adresse mbs dans des informations mbs reçues

Citations (2)

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US20170310718A1 (en) * 2014-10-27 2017-10-26 Lg Electronics Inc. Method and apparatus for providing service continuity in mbsfn service boundary area
US20180359614A1 (en) * 2013-03-22 2018-12-13 Mediatek Inc. Service Continuity for Group Communication over LTE eMBMS

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US20180359614A1 (en) * 2013-03-22 2018-12-13 Mediatek Inc. Service Continuity for Group Communication over LTE eMBMS
US20170310718A1 (en) * 2014-10-27 2017-10-26 Lg Electronics Inc. Method and apparatus for providing service continuity in mbsfn service boundary area

Non-Patent Citations (3)

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AT&T: "Proposed initial technical requirements for RAN and SA2 in support of MBMS/5G for MC", 3GPP DRAFT; S6-191648 DISCUSSION AND PROPOSED LS, vol. SA WG6, 25 August 2019 (2019-08-25), Sophia Antipolis, France, pages 1 - 2, XP051777006 *
OPPO: "Solution for broadcast and unicast switching", 3GPP DRAFT; S2-2000328, vol. SA WG2, 7 January 2020 (2020-01-07), Incheon, Korea, pages 1 - 3, XP051842400 *
QUALCOMM INCORPORATED: "Solution: Integrated MBS and Unicast Transport with Full Separation of MBS Service", 3GPP DRAFT; S2-1911371, vol. SA WG2, 8 November 2019 (2019-11-08), Reno, Nevada, USA, pages 1 - 6, XP051821463 *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023066188A1 (fr) * 2021-10-19 2023-04-27 夏普株式会社 Procédé de transfert intercellulaire de cellule et équipement utilisateur
WO2023069375A1 (fr) * 2021-10-21 2023-04-27 Google Llc Gestion de transmissions de diffusion individuelle, de multidiffusion et de diffusion
EP4346243A1 (fr) * 2022-09-30 2024-04-03 MediaTek Inc. Décodage d'informations d'adresse mbs dans des informations mbs reçues

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