Communication system, communication terminal device, and base station device

Abstract

In NR (New Radio), a communication system that is high-speed and has high reliability and low latency is provided. A communication system (200) includes a communication terminal device (202) and a base station device (203) configured to be able to perform wireless communication with the communication terminal device (202). The communication terminal device (202) is configured to be able to duplicate a packet and to be able to transmit the duplicated packet using carrier aggregation. The base station device (203) transmits, to the communication terminal device (202), packet duplication control related to packet duplication and secondary cell control related to a secondary cell used in carrier aggregation. The communication terminal device (202) performs the packet duplication control and the secondary cell control based on a priority order determined between the packet duplication control and the secondary cell control.

Description

[0001] This application is a divisional application of the application filed on August 7, 2018, with application number 201880050388.2, entitled "Communication System, Communication Terminal Apparatus and Base Station Apparatus". Technical Field

[0002] The present invention relates to a communication system for wireless communication between a communication terminal device such as a mobile terminal device and a base station device. Background Technology

[0003] Within the 3GPP (3rd Generation Partnership Project), the standardization organization for mobile communication systems, a communication method known as Long Term Evolution (LTE) in terms of the radio domain and System Architecture Evolution (SAE) in terms of the overall system architecture including the core network and the radio access network (hereinafter collectively referred to as the network) has been studied (e.g., Non-Patent Documents 1-5). This communication method is also referred to as a 3.9G (3.9 Generation) system.

[0004] As an access method for LTE, the downlink direction uses OFDM (Orthogonal Frequency Division Multiplexing), and the uplink direction uses SC-FDMA (Single Carrier Frequency Division Multiple Access). Furthermore, unlike W-CDMA (Wideband Code Division Multiple Access), LTE does not include line switching; it is solely a packet communication method.

[0005] use Figure 1 To explain the decisions made in 3GPP concerning the frame structure of the LTE system as described in Non-Patent Document 1 (Chapter 5). Figure 1 This is an explanatory diagram showing the structure of the radio frame used in an LTE communication system. Figure 1In this system, a radio frame is 10ms long. A radio frame is divided into 10 equal-sized subframes. Each subframe is further divided into two equal-sized slots. The first and sixth subframes of each radio frame contain downlink synchronization signals. These synchronization signals include a primary synchronization signal (P-SS) and a secondary synchronization signal (S-SS).

[0006] Non-Patent Document 1 (Chapter 5) describes the decisions made by 3GPP regarding channel structure in LTE systems. It is assumed that CSG (Closed Subscriber Group) cells also use the same channel structure as non-CSG cells.

[0007] The Physical Broadcast Channel (PBCH) is a downlink transmission channel from a base station (hereinafter sometimes referred to as "base station") to a mobile terminal device (hereinafter sometimes referred to as "mobile terminal") or other communication terminal device (hereinafter sometimes referred to as "communication terminal"). A BCH transport block is mapped to four subframes in a 40ms interval. There is no clear signaling at 40ms intervals.

[0008] The Physical Control Format Indicator Channel (PCFICH) is a downlink transmission channel from the base station to the communication terminal. The PCFICH informs the communication terminal from the base station about the number of OFDM (Orthogonal Frequency Division Multiplexing) symbols used for PDCCHs. The PCFICH is transmitted per subframe.

[0009] The Physical Downlink Control Channel (PDCCH) is the downlink transmission channel from the base station to the communication terminal. The PDCCH notifies the recipients of resource allocation information for the Downlink Shared Channel (DL-SCH), one of the transport channels described later; resource allocation information for the Paging Channel (PCH), another transport channel described later; and HARQ (Hybrid Automatic Repeat reQuest) information related to the DL-SCH. The PDCCH transmits uplink scheduling grants. It also transmits response signals for uplink transmissions, namely Ack (Acknowledgement) and Nack (Negative Acknowledgement). The PDCCH is also known as the L1 / L2 control signal.

[0010] The Physical Downlink Shared Channel (PDSCH) is the downlink transmission channel from the base station to the communication terminal. The PDSCH maps to both the Downlink Shared Channel (DL-SCH) used as the transport channel and the PCH used as the transport channel.

[0011] The Physical Multicast Channel (PMCH) is a downlink transmission channel from the base station to the communication terminal. The PMCH maps to the Multicast Channel (MCH), which serves as the transport channel.

[0012] The Physical Uplink Control Channel (PUCCH) is the uplink transmission channel from the communication terminal to the base station. The PUCCH transmits response signals (Ack / Nack) for downlink transmissions. It also transmits CQI (Channel Quality Indicator) reports. CQI indicates the quality of received data or the quality of the communication line. Furthermore, the PUCCH transmits scheduling requests (SRs).

[0013] The Physical Uplink Shared Channel (PUSCH) is the uplink transmission channel from the communication terminal to the base station. The PUSCH maps to the Uplink Shared Channel (UL-SCH), which is one of the transmission channels.

[0014] The Physical Hybrid ARQ Indicator Channel (PHICH) is the downlink transmission channel from the base station to the communication terminal. PHICH transmits the Ack / Nack response signals sent in response to the uplink transmission. The Physical Random Access Channel (PRACH) is the uplink transmission channel from the communication terminal to the base station. PRACH transmits the random access preamble.

[0015] Downlink reference signals (RS) are symbols known in LTE communication systems. Five types of downlink reference signals are defined: Cell-specific Reference Signal (CRS), MBSFN Reference Signal, UE-specific Reference Signal (DM-RS, also known as Demodulation Reference Signal), Positioning Reference Signal (PRS), and Channel State Information Reference Signal (CSI-RS). As a physical layer measurement of the communication terminal, the Received Power of the Reference Signal (RSRP) is also measured.

[0016] The transport channel described in Non-Patent Document 1 (Chapter 5) will be explained. The broadcast channel (BCH) in the downlink transport channel is broadcast to the entire coverage area of ​​its base station (cell). The BCH is mapped to the physical broadcast channel (PBCH).

[0017] The Downlink Shared Channel (DL-SCH) employs HARQ (Hybrid ARQ)-based retransmission control. DL-SCH can broadcast across the entire coverage area of ​​a base station (cell). DL-SCH supports dynamic or semi-static resource allocation. Semi-static resource allocation is also known as persistent scheduling. DL-SCH supports discontinuous reception (DRX) of communication terminals to reduce power consumption. DL-SCH is mapped to the Physical Downlink Shared Channel (PDSCH).

[0018] The Paging Channel (PCH) supports DRX (Demand Reduction) of communication terminals to reduce power consumption. The PCH is required to broadcast over the entire coverage area of ​​the base station (cell). The PCH is mapped to physical resources such as the Physical Downlink Shared Channel (PDSCH) that can be dynamically utilized for traffic.

[0019] The Multicast Channel (MCH) is used to broadcast to the entire coverage area of ​​a base station (cell). The MCH supports SFN synthesis of MBMS (Multimedia Broadcast Multicast Service) services (MTCH and MCCH) in multi-cell transmission. The MCH supports quasi-static resource allocation. The MCH is mapped to the PMCH.

[0020] HARQ (Hybrid ARQ) based retransmission control is applied to the Uplink Shared Channel (UL-SCH) in the uplink transport channel. UL-SCH supports dynamic or semi-static resource allocation. UL-SCH is mapped to the Physical Uplink Shared Channel (PUSCH).

[0021] The Random Access Channel (RACH) is restricted to control information. RACH is subject to collision risks. RACH is mapped to the Physical Random Access Channel (PRACH).

[0022] HARQ is explained below. HARQ is a technique that improves the communication quality of a transmission line by combining Automatic Repeat Request (ARQ) and Forward Error Correction. HARQ has the following advantages: even for transmission lines where communication quality changes, retransmission can effectively enable error correction. In particular, during retransmission, the quality can be further improved by combining the received results of the initial transmission with those of the retransmission.

[0023] Here's an example illustrating the retransmission method. If the receiving side cannot correctly decode the received data—in other words, if a CRC (Cyclic Redundancy Check) error occurs (CRC = NG)—a "Nack" is sent from the receiving side to the sending side. The sending side, upon receiving the "Nack," retransmits the data. If the receiving side can correctly decode the received data—in other words, if no CRC error occurs (CRC = OK)—an "Ack" is sent from the receiving side to the sending side. The sending side, upon receiving the "Ack," transmits the next data.

[0024] The logical channel described in Non-Patent Document 1 (Chapter 6) will be explained. The Broadcast Control Channel (BCCH) is a downlink channel used to broadcast system control information. The BCCH, as a logical channel, is mapped to either the Broadcast Channel (BCH) as a transmission channel or the Downlink Shared Channel (DL-SCH).

[0025] The Paging Control Channel (PCCH) is a downlink channel used to transmit paging information and system information updates. The PCCH is used when the network is unaware of the cell location of the communicating terminal. As a logical channel, the PCCH is mapped to the Paging Channel (PCH), which is used as a transport channel.

[0026] The Common Control Channel (CCCH) is a channel used for transmitting control information between a communication terminal and a base station. The CCCH is used when there is no RRC connection between the communication terminal and the network. In the downlink direction, the CCCH is mapped to the Downlink Shared Channel (DL-SCH) used as a transport channel. In the uplink direction, the CCCH is mapped to the Uplink Shared Channel (UL-SCH) used as a transport channel.

[0027] The Multicast Control Channel (MCCH) is a downlink channel used for point-to-multipoint transmission. The MCCH is used to send one or more MBMS control messages (MTCHs) from the network to the communication terminal. The MCCH is only used by the communication terminal during the MBMS reception process. The MCCH is mapped to the Multicast Channel (MCH), which serves as the transport channel.

[0028] The Dedicated Control Channel (DCCH) is a channel used to transmit dedicated control information between a communication terminal and the network in a point-to-point manner. The DCCH is used when the communication terminal is in an RRC connection. In the uplink, the DCCH is mapped to the Uplink Shared Channel (UL-SCH), and in the downlink, it is mapped to the Downlink Shared Channel (DL-SCH).

[0029] A Dedicated Traffic Channel (DTCH) is a point-to-point communication channel used to send user information to dedicated communication terminals. DTCH exists in both the uplink and downlink. In the uplink, DTCH is mapped to the Uplink Shared Channel (UL-SCH), and in the downlink, it is mapped to the Downlink Shared Channel (DL-SCH).

[0030] The Multicast Traffic Channel (MTCH) is a downlink channel used to send voice data from the network to the communication terminal. The MTCH is used only by the communication terminal during MBMS reception. The MTCH is mapped to the Multicast Channel (MCH).

[0031] CGI stands for Cell Global Identifier. ECGI stands for E-UTRAN Cell Global Identifier. In LTE, LTE-A (Long Term Evolution Advanced) (described later), and UMTS (Universal Mobile Telecommunication System), CSG (Closed Subscriber Group) cells were introduced.

[0032] A CSG (Closed Subscriber Group) cell is a cell designated by operators as having access rights to a subscriber (sometimes referred to as a "subscriber-specific cell"). The designated subscriber is permitted access to more than one cell within a PLMN (Public Land Mobile Network). The more than one cell that has granted access to the designated subscriber is called a "CSG cell(s)". However, PLMNs have access restrictions.

[0033] A CSG cell is part of a PLMN that broadcasts its inherent CSG identity (CSG ID) and uses CSG indication to broadcast "TRUE". Members of a pre-registered and authorized joiner group access the CSG cell using the CSG ID in their access permission information.

[0034] CSG IDs are broadcast by the CSG cell or the cell itself. Multiple CSG IDs exist in LTE communication systems. Furthermore, the CSG ID is used by the user terminal (UE) to facilitate access to CSG-associated members.

[0035] Location tracking of a communication terminal is performed on a unit consisting of one or more cells. Location tracking is used to locate the communication terminal even in standby mode, enabling calls to the terminal; in other words, it is performed to enable calls to the communication terminal. The area used for location tracking of this communication terminal is called the tracking area.

[0036] In 3GPP, base stations referred to as Home-NodeB (Home-NB; HNB) and Home-eNodeB (Home-eNB; HeNB) have been studied. HNBs in UTRAN and HeNBs in E-UTRAN are, for example, base stations providing access services for homes, corporations, and businesses. Non-Patent Document 2 discloses three different modes for accessing HeNBs and HNBs. Specifically, it discloses Open access mode, Closed access mode, and Hybrid access mode.

[0037] Furthermore, within 3GPP, the standardization of Long Term Evolution Advanced (LTE-A), version 10, is progressing steadily (see Non-Patent Documents 3 and 4). LTE-A is based on the radio inter-communication method of LTE, and is constructed by adding several new technologies.

[0038] In LTE-A systems, to support wider transmission bandwidths of up to 100MHz, carrier aggregation (CA), which combines two or more component carriers (CCs), has been studied. CA is described in Non-Patent Literature 1.

[0039] In the case of a CA (Cybernetic Association), the UE has a unique RRC connection with the network (NW). Within the RRC connection, a serving cell provides NAS (Navigation Information and Security) input. This cell is called the Primary Cell (PCel1). In the downlink, the carrier corresponding to PCel1 is the Downlink Primary Component Carrier (DL PCC). In the uplink, the carrier corresponding to PCel1 is the Uplink Primary Component Carrier (UL PCC).

[0040] Based on the UE's capabilities, secondary cells (SCell) are constructed to form a group of serving cells together with PCell. In the downlink, the carrier corresponding to the SCell is the downlink secondary component carrier (DL SCC). In the uplink, the carrier corresponding to the SCell is the uplink secondary component carrier (UL SCC).

[0041] For a UE, a group of serving cells is formed by one PCell and one or more SCells.

[0042] Furthermore, as a new technology for LTE-A, there are technologies that support wider bandwidth (Wider bandwidth extension) and Coordinated Multiple Point Transmission and Reception (CoMP) technology. CoMP, which was researched for the implementation of LTE-A in 3GPP, is described in Non-Patent Literature 1.

[0043] Furthermore, 3GPP is researching the use of small eNBs (hereinafter sometimes referred to as "small-scale base station devices") to cope with the massive traffic volume expected in the future. For example, technologies are being researched to improve frequency utilization efficiency and increase communication capacity by setting up multiple small eNBs and forming multiple small cells. Specifically, there is dual connectivity (DC), where the UE communicates by connecting to two eNBs. DC is described in Non-Patent Document 1.

[0044] Sometimes one of the eNBs that perform dual connections (DC) is called the "primary eNB (MeNB)" and the other is called the "secondary eNB (SeNB)".

[0045] Mobile network traffic is trending upwards, and communication speeds are continuously increasing. With the official implementation of LTE and LTE-A, further acceleration in communication speeds is foreseeable.

[0046] Furthermore, fifth-generation (hereinafter sometimes referred to as "5G") radio access systems are under investigation, with the goal of enabling next-generation mobile communications to begin service after 2020. For example, in Europe, the organization METIS is summarizing the requirements for 5G (see Non-Patent Document 5).

[0047] In 5G wireless access systems, for LTE systems, assuming the system capacity is 1000 times greater, the data transmission speed is 100 times greater, the data processing latency is 1 / 10th, and the number of simultaneous connections of communication terminals is 100 times greater, we can list the necessary conditions for achieving further low power consumption and low device cost.

[0048] To meet these requirements, the 5G standard is under continuous discussion in 3GPP as version 14 (see Non-Patent Documents 6-10). The technology for 5G radio bands is called "New Radio Access Technology" (NR), and several new technologies are under discussion (see Non-Patent Documents 11-14). For example, the use of DC, multi-connectivity (MC) packet replication, and the separation of the CU (Central Unit) and DU (Distributed Unit) for gNBs are being explored.

[0049] Existing technical documents

[0050] Non-patent literature

[0051] Non-patent literature 1: 3GPP TS 36.300V14.3.0

[0052] Non-patent document 2: 3GPP S1-083461

[0053] Non-patent document 3: 3GPP TR 36.814V9.2.0

[0054] Non-patent document 4: 3GPP TR 36.912V14.0.0

[0055] Non-patent literature 5: "Scenarios, requirements and KPIs for 5G mobile and wireless system", ICT-317669-METIS / D1.1

[0056] Non-patent document 6: 3GPP TR 23.799V14.0.0

[0057] Non-patent document 7: 3GPP TR 38.801V14.0.0

[0058] Non-patent document 8: 3GPP TR 38.802V14.1.0

[0059] Non-patent document 9: 3GPP TR 38.804V14.0.0

[0060] Non-patent document 10: 3GPP TR 38.912V14.0.0

[0061] Non-patent document 11: 3GPP R2-1700672

[0062] Non-patent document 12: Draft Report of 3GPP TSG RAN WG2 meeting #98, Hangzhou, China, May 15-19, 2017

[0063] Non-patent document 13: 3GPP R2-1704578

[0064] Non-patent document 14: 3GPP R2-1704660

[0065] Non-patent document 15: 3GPP TS 36.321v14.3.0

[0066] Non-patent document 16: 3GPP R2-1706867

[0067] Non-patent document 17: 3GPP TS 36.322v14.0.0

[0068] Non-patent literature 18: 3GPP R3-171412

[0069] Non-patent document 19: 3GPP R2-1706716

[0070] Non-patent document 20: 3GPP R2-1704836

[0071] Non-patent literature 21: 3GPP R2-1702753

[0072] Non-patent document 22: 3GPP R2-1704001

[0073] Non-patent document 23: 3GPP TS 36.423v14.3.0

[0074] Non-patent document 24: 3GPP TS 36.331v14.3.0

[0075] Non-patent document 25: 3GPP R2-1704425

[0076] Non-patent document 26: 3GPP R2-1704420

[0077] Non-patent document 27: 3GPP R2-167583

[0078] Non-patent document 28: 3GPP TS 37.340v0.2.0

[0079] Non-patent document 29: 3GPP TS 38.423v0.1.1 Summary of the Invention

[0080] The technical problem that the invention aims to solve

[0081] In NR (Network Response) systems, packet replication is encouraged to achieve highly reliable and low-latency communication. Common methods for implementing packet replication include CA (Concurrent Access) and DC (Concurrent Distributed Access). The start and stop of packet replication are controlled using MAC (Macro-MAC) signaling.

[0082] Furthermore, as existing technology, MAC signaling is supported for starting / stopping the operation of SCells used in CA. However, in NRs using CA, the actions taken when the MAC signaling for packet replication conflicts with the MAC signaling for SCell start / stop are not disclosed. Therefore, when such a conflict occurs, the UE is unaware of how to handle packet replication, potentially leading to malfunctions. As a result, highly reliable and low-latency communication may not be achievable.

[0083] Furthermore, in NR (Radio Frequency Identification), MC (Multi-Base Station) is proposed as a technology for achieving high-speed communication. As an MC, the scenario of configuring a UE to connect a primary base station to multiple secondary base stations was discussed. However, for MCs with two or more secondary base stations, the architecture including the upper-level NW (Network Wireless Switching) and methods for configuring multiple secondary base stations are not disclosed. Therefore, the primary base station and secondary base stations cannot form the aforementioned MC, and the UE cannot perform high-speed communication.

[0084] In view of the above problems, one of the objectives of the present invention is to provide a high-speed communication system with high reliability and low latency in NR.

[0085] Technical solutions adopted to solve technical problems

[0086] According to the present invention, for example, a communication system is provided, comprising a communication terminal device and a base station device configured to wirelessly communicate with the communication terminal device, the communication terminal device being configured to copy packets and transmit the copied packets using carrier aggregation, the base station device transmitting packet copying control related to packet copying and secondary cell control related to secondary cells used in carrier aggregation to the communication terminal device, the communication terminal device performing the packet copying control and the secondary cell control based on a priority order determined between the packet copying control and the secondary cell control.

[0087] Furthermore, according to the present invention, for example, a communication terminal device is provided, configured to wirelessly communicate with a base station device, the communication terminal device being configured to copy packets and transmit the copied packets using carrier aggregation, the communication terminal device receiving packet copying control related to packet copying and secondary cell control related to secondary cells used in carrier aggregation from the base station device, and performing the packet copying control and the secondary cell control based on a priority order determined between the packet copying control and the secondary cell control.

[0088] Furthermore, according to the present invention, for example, a base station apparatus is provided, configured to wirelessly communicate with a communication terminal apparatus, the communication terminal apparatus being configured to copy packets and transmit the copied packets using carrier aggregation, the communication terminal apparatus performing packet copying control related to packet copying and secondary cell control related to secondary cells used in carrier aggregation based on a priority order determined between the packet copying control and the secondary cell control, the base station apparatus transmitting the packet copying control and the secondary cell control to the communication terminal apparatus.

[0089] Invention Effects

[0090] According to the present invention, a high-speed communication system with high reliability and low latency is provided in NR.

[0091] The objects, features, aspects, and advantages of the present invention will become more apparent from the following detailed description and accompanying drawings. Attached Figure Description

[0092] Figure 1 This is an explanatory diagram showing the structure of the radio frame used in an LTE communication system.

[0093] Figure 2 This is a block diagram showing the overall structure of a communication system 200 using the LTE method discussed in 3GPP.

[0094] Figure 3 This illustrates the communication terminal involved in the present invention. Figure 2 The diagram shows the structure of the mobile terminal 202.

[0095] Figure 4 This illustrates the base station involved in the present invention. Figure 2 The diagram shows the structure of base station 203.

[0096] Figure 5 This is a block diagram illustrating the structure of the MME involved in this invention.

[0097] Figure 6 This is a flowchart illustrating the process from cell search to standby mode performed by a communication terminal (UE) in an LTE communication system.

[0098] Figure 7 This is a diagram illustrating the concept of a cell structure when macro eNBs and small eNBs are mixed together.

[0099] Figure 8 This is a flowchart illustrating the actions of the MAC signaling at the start of packet replication in Implementation 1, where a HARQ retransmission is generated so that the UE can receive it after a specified time interval.

[0100] Figure 9 This is a diagram illustrating the protocol structure of packet replication using CA between the gNB and UE, which have undergone CU-DU separation, in a variation 1 of Implementation 1.

[0101] Figure 10 This is a flowchart of group copying in a variation of implementation 1, where DU determines that group copying has started.

[0102] Figure 11 This is a flowchart of group copying in a variation of implementation 1, where the CU determines that group copying has started.

[0103] Figure 12 This is a flowchart illustrating the actions taken by the UE after a specified time interval when the MAC signaling at the start of packet copying is retransmitted due to HARQ, as described in Variation 1 of Implementation Method 1.

[0104] Figure 13 This is a flowchart of the handover scenario in Implementation 2, where packet replication is initiated by the main base station.

[0105] Figure 14 This is a flowchart of the handover scenario in Implementation 2, where packet replication is initiated by the secondary base station.

[0106] Figure 15 This is a flowchart illustrating the small data transmission from the UE to the secondary base station in Implementation 5.

[0107] Figure 16 This is a diagram illustrating the architecture of MC in implementation method 6.

[0108] Figure 17 This is a diagram illustrating an example of the process of setting the MC in Implementation 6.

[0109] Figure 18 This is a diagram illustrating an example of the process of setting the MC in Implementation 6.

[0110] Figure 19 This is a diagram illustrating an example of the process of setting the MC in Implementation 6.

[0111] Figure 20 This is a diagram illustrating an example of the process of setting the MC in Implementation 6.

[0112] Figure 21 This is a diagram showing the architecture and data flow in a variation of Implementation 6, where the upper-level NW is NG-CN and the base station is an NR gNB.

[0113] Figure 22 This is a diagram showing the architecture of MC in a variation of embodiment 6, example 1.

[0114] Figure 23 This is a schematic diagram showing the data flow in a variation of embodiment 6, where the MC is set for each DRB.

[0115] Figure 24 This is a schematic diagram showing the data flow in a variation of embodiment 6, where the MC is set for each QoS flow.

[0116] Figure 25 This is a schematic diagram showing the data flow in a modified example 1 of embodiment 6, where a DRB is added to map the QoS stream that performs MC.

[0117] Figure 26 This is an example of a process in variation 1 of implementation 6, where the MC is set for each QoS flow.

[0118] Figure 27 This is an example of a process in variation 1 of implementation 6, where the MC is set for each QoS flow.

[0119] Figure 28 This is a diagram illustrating the architecture of MC in Implementation 7.

[0120] Figure 29 This is a diagram illustrating an example of the process of setting up an MC that uses an SCG bearer in Implementation 7.

[0121] Figure 30 This is a diagram illustrating an example of the process of setting up an MC that uses an SCG bearer in Implementation 7.

[0122] Figure 31 This is a diagram showing the architecture of the MC using SCG in a variation 1 of embodiment 7.

[0123] Figure 32 This is a schematic diagram showing the data flow in a variant 1 of embodiment 7, where the MC using SCG bearer is set per DRB.

[0124] Figure 33 This is a diagram illustrating an example of the process of setting the MC using SGB bearer when the upper NW is NG-CN in a variation 1 of embodiment 7.

[0125] Figure 34 This is a diagram illustrating an example of the process of setting the MC using SGB bearer when the upper NW is NG-CN in a variation 1 of embodiment 7.

[0126] Figure 35 This is a diagram illustrating an example of the process of setting the MC using SGB bearer when the upper NW is NG-CN in a variation 1 of embodiment 7.

[0127] Figure 36 This is a schematic diagram showing the data flow in a variation 1 of embodiment 7, where the MC using SCG bearers is configured for each QoS flow.

[0128] Figure 37 This is a diagram illustrating the architecture of MC in implementation method 8.

[0129] Figure 38This is a diagram illustrating an example of the process for setting up an MC that uses an SCG fork bearer in Implementation 8.

[0130] Figure 39 This is a diagram illustrating an example of the process for setting up an MC that uses an SCG fork bearer in Implementation 8.

[0131] Figure 40 This is a diagram illustrating an example of the process for setting up an MC that uses an SCG fork bearer in Implementation 8.

[0132] Figure 41 This is a diagram showing the architecture of MC in a variation of embodiment 8, example 1.

[0133] Figure 42 This is a schematic diagram showing the data flow in a variant 1 of embodiment 8, where the MC using the SCG fork bearer is set for each DRB.

[0134] Figure 43 This is a diagram illustrating an example of the process of setting up an MC using an SCG fork carrier in a variation 1 of embodiment 8.

[0135] Figure 44 This is a diagram illustrating an example of the process of setting up an MC using an SCG fork carrier in a variation 1 of embodiment 8.

[0136] Figure 45 This is a diagram illustrating an example of the process of setting up an MC using an SCG fork carrier in a variation 1 of embodiment 8.

[0137] Figure 46 This is a schematic diagram showing the data flow in a variant 1 of embodiment 8, where the MC using SCG fork bearer is configured for each QoS flow.

[0138] Figure 47 This is a diagram illustrating the architecture of MC in implementation method 9.

[0139] Figure 48 This is a diagram showing the architecture of MC in a variation 1 of embodiment 9. Detailed Implementation

[0140] Implementation Method 1.

[0141] Figure 2 This is a block diagram representing the overall structure of a communication system 200 using the LTE method discussed in 3GPP. Figure 2The following explanation is provided. The radio access network is referred to as E-UTRAN (Evolved Universal Terrestrial Radio Access Network) 201. The communication terminal device, namely the mobile terminal device (hereinafter referred to as "Mobile Terminal (User Equipment): UE)") 202, can wirelessly communicate with the base station device (hereinafter referred to as "Base Station (E-UTRAN NodeB): eNB)") 203, and use wireless communication to transmit and receive signals.

[0142] Here, "communication terminal device" refers not only to mobile terminal devices such as mobile phone terminals, but also to stationary devices such as sensors. In the following description, "communication terminal device" may sometimes be abbreviated as "communication terminal".

[0143] If the control protocols for the mobile terminal 202, such as RRC (Radio Resource Control), and user-level protocols (hereinafter sometimes referred to as U-Plane), such as PDCP (Packet Data Convergence Protocol), RLC (Radio Link Control), MAC (Medium Access Control), and PHY (Physical layer), terminate at the base station 203, then the E-UTRAN consists of one or more base stations 203.

[0144] The Radio Resource Control (RRC) protocol between mobile terminal 202 and base station 203 performs broadcasting, paging, and RRC connection management. The states of base station 203 and mobile terminal 202 in the RRC are RRC_IDLE and RRC_CONNECTED.

[0145] During RRC_IDLE, PLMN (Public Land Mobile Network) selection, System Information (SI) broadcasting, paging, cell re-selection, and mobility checks are performed. During RRC_CONNECTED, the mobile terminal has an RRC connection and can send and receive data with the network. Furthermore, during RRC_CONNECTED, handover (HO) and neighbor cell determination (measurement) are also performed.

[0146] Base station 203 is classified into eNB 207 and Home-eNB 206. Communication system 200 includes eNB group 203-1 containing multiple eNBs 207, and Home-eNB group 203-2 containing multiple Home-eNBs 206. Furthermore, the system consisting of EPC (Evolved Packet Core) as the core network and E-UTRAN 201 as the radio access network is called EPS (Evolved Packet System). Sometimes, EPC as the core network and E-UTRAN 201 as the radio access network are collectively referred to as the "network".

[0147] The eNB 207 connects to the Mobility Management Entity (MME), or the Serving Gateway (S-GW), or an MME / S-GW unit (hereinafter sometimes referred to as "MME unit") 204, which includes both the MME and S-GW, via the S1 interface, and communicates control information between the eNB 207 and the MME unit 204. Multiple MME units 204 can be connected to a single eNB 207. The eNBs 207 connect to each other via the X2 interface, and communicate control information between them.

[0148] The Home-eNB 206 connects to the MME unit 204 via the S1 interface, and communication of control information between the Home-eNB 206 and the MME unit 204 is performed. One MME unit 204 can be connected to multiple Home-eNB 206s. Alternatively, the Home-eNB 206 connects to the MME unit 204 via the HeNBGW (Home-eNB Gateway) 205. The Home-eNB 206 and HeNBGW 205 are connected via the S1 interface, and the HeNBGW 205 and MME unit 204 are connected via the S1 interface.

[0149] One or more Home-eNB206s are connected to one HeNBGW205 and communicate via the S1 interface. The HeNBGW205 is connected to one or more MME units 204 and communicates via the S1 interface.

[0150] MME 204 and HeNBGW 205 are upper-level devices, specifically upper-level nodes, that control the connection between eNB 207 and Home-eNB 206 (which act as base stations) and mobile terminal (UE) 202. MME 204 constitutes the EPC (Engineering Process Control) as the core network. Base station 203 and HeNBGW 205 constitute E-UTRAN 201.

[0151] Furthermore, the following structure was studied in 3GPP. It supports the X2 interface between Home-eNBs 206. That is, Home-eNBs 206 are connected via the X2 interface, and control information is communicated between them. From the perspective of MME 204, HeNBGW 205 can be considered as a Home-eNB 206. From the perspective of Home-eNB 206, HeNBGW 205 can be considered as MME 204.

[0152] Whether the Home-eNB206 is connected to the MME unit 204 via the HeNBGW205 or directly to the MME unit 204, the interface between the Home-eNB206 and the MME unit 204 is always the S1 interface.

[0153] Base station 203 can constitute one cell or multiple cells. Each cell has a predetermined range as its coverage area, which enables communication with mobile terminal 202, and wireless communication is conducted with mobile terminal 202 within the coverage area. When a base station 203 constitutes multiple cells, each cell is configured to communicate with mobile terminal 202.

[0154] Figure 3 This refers to the communication terminal involved in this invention. Figure 2The diagram shows the structure of the mobile terminal 202. Figure 3 The transmission process of the mobile terminal 202 shown will be described. First, control data from the protocol processing unit 301 and user data from the application unit 302 are stored in the transmission data buffer unit 303. The data stored in the transmission data buffer unit 303 is transmitted to the encoder unit 304 for encoding processing such as error correction. Alternatively, data may be output directly from the transmission data buffer unit 303 to the modulation unit 305 without encoding processing. The data encoded by the encoding unit 304 is modulated in the modulation unit 305. The modulated data is converted into a baseband signal and then output to the frequency conversion unit 306, where it is converted into a wireless transmission frequency. Afterward, the transmission signal is transmitted from the antenna 307 to the base station 203.

[0155] Furthermore, the receiving process of the mobile terminal 202 is performed as follows: The antenna 307 receives the wireless signal from the base station 203. The received signal is converted from the wireless receiving frequency to a baseband signal by the frequency conversion unit 306, and demodulated in the demodulation unit 308. The demodulated data is transmitted to the decoding unit 309 for error correction and other decoding processes. Of the decoded data, control data is transmitted to the protocol processing unit 301, and user data is transmitted to the application unit 302. A series of processes of the mobile terminal 202 are controlled by the control unit 310. Thus, although in Figure 3 The details have been omitted, but the control unit 310 is connected to each of the units 301 to 309.

[0156] Figure 4 This illustrates the base station involved in the present invention. Figure 2 The diagram shows the structure of base station 203. Figure 4 The transmission processing of the base station 203 shown will be described. The EPC communication unit 401 handles data transmission and reception between base station 203 and EPC (MME unit 204, etc.), HeNBGW 205, etc. Other base station communication units 402 handle data transmission and reception with other base stations. The EPC communication unit 401 and other base station communication units 402 exchange information with the protocol processing unit 403. Control data from the protocol processing unit 403, as well as user data and control data from the EPC communication unit 401 and other base station communication units 402, are stored in the transmission data buffer unit 404.

[0157] The data stored in the transmission data buffer 404 is transmitted to the encoder 405 for encoding processing such as error correction. Alternatively, data may be output directly from the transmission data buffer 404 to the modulation unit 406 without encoding processing. The encoded data is modulated in the modulation unit 406. The modulated data is converted into a baseband signal and then output to the frequency conversion unit 407, where it is converted into a wireless transmission frequency. Afterward, the transmission signal is transmitted to one or more mobile terminals 202 using the antenna 408.

[0158] Furthermore, the reception processing of base station 203 is performed as follows. Wireless signals from one or more mobile terminals 202 are received by antenna 408. The received signal is converted from a wireless receiving frequency to a baseband signal by frequency conversion unit 407, and demodulated by demodulation unit 409. The demodulated data is transmitted to decoding unit 410 for error correction and other decoding processing. Of the decoded data, control data is transmitted to protocol processing unit 403, or EPC communication unit 401, or other base station communication units 402; user data is transmitted to EPC communication unit 401 and other base station communication units 402. A series of processes of base station 203 are controlled by control unit 411. Thus, although in Figure 4 The details have been omitted, but the control unit 411 is connected to each of the units 401 to 410.

[0159] Figure 5 This is a block diagram illustrating the structure of the MME involved in this invention. Figure 5 The above is shown in the middle. Figure 2 The structure of MME 204a included in MME 204 is shown. PDN GW communication unit 501 performs data transmission and reception between MME 204a and PDN GW. Base station communication unit 502 performs data transmission and reception between MME 204a and base station 203 via the S1 interface. When the data received from the PDN GW is user data, the user data is transmitted from PDN GW communication unit 501 to base station communication unit 502 via user plane communication unit 503, and then sent to one or more base stations 203. When the data received from base station 203 is user data, the user data is transmitted from base station communication unit 502 to PDN GW communication unit 501 via user plane communication unit 503, and then sent to PDN GW.

[0160] When the data received from the PDN GW is control data, the control data is transmitted from the PDN GW communication unit 501 to the control plane control unit 505. When the data received from the base station 203 is control data, the control data is transmitted from the base station communication unit 502 to the control plane control unit 505.

[0161] With HeNBGW205 present, HeNBGW communication unit 504 is set up to perform data transmission and reception between MME204a and HeNBGW205 via interface (IF) according to the information type. Control data received from HeNBGW communication unit 504 is transmitted from HeNBGW communication unit 504 to control plane control unit 505. The processing results in control plane control unit 505 are sent to PDN GW via PDNGW communication unit 501. In addition, the results processed by control plane control unit 505 are sent to one or more base stations 203 via base station communication unit 502 and S1 interface, or sent to one or more HeNBGW205 via HeNBGW communication unit 504.

[0162] The control plane control unit 505 includes a NAS security unit 505-1, an SAE bearer control unit 505-2, and an idle state mobility management unit 505-3, and performs all processing for the control plane (hereinafter sometimes referred to as C-Plane). The NAS security unit 505-1 handles the security of NAS (Non-Access Stratum) messages. The SAE bearer control unit 505-2 manages the SAE (System Architecture Evolution) bearer. The idle state mobility management unit 505-3 manages mobility in standby state (idle state; LTE-IDLE state, or simply idle), generates and controls paging signals in standby state, adds, deletes, updates, retrieves, and manages the tracking area list for one or more mobile terminals 202 within the coverage area.

[0163] MME204a distributes paging signals to one or more base stations 203. Furthermore, MME204a performs mobility control in the idle state. MME204a manages the tracking area list when the mobile terminal is in idle state and in active state. MME204a initiates the paging protocol by sending a paging message to cells belonging to the tracking area registered by the UE. The management of the CSG, CSG ID, and whitelist of the Home-eNB206 connected to MME204a can be performed by the idle state mobility management unit 505-3.

[0164] Next, an example of a cell search method in a communication system is shown. Figure 6This is a flowchart illustrating the process of a communication terminal (UE) in an LTE communication system from cell search to standby operation. If the communication terminal starts cell search, in step ST601, the first synchronization signal (P-SS) and the second synchronization signal (S-SS) sent from the surrounding base stations are used to obtain the synchronization of time slot timing and frame timing.

[0165] P-SS and S-SS are collectively referred to as Synchronization Signal (SS). The Synchronization Signal (SS) contains a synchronization code that corresponds one-to-one with the PCI assigned to each cell. This paper explores setting the number of PCIs to 504. Synchronization is achieved using these 504 PCIs, and the PCIs of synchronized cells are detected (determined).

[0166] Next, in step ST602, the reference signal (RS) sent from the base station to each cell after synchronization is achieved, i.e., the cell-specific reference signal (CRS), is measured, and the received power (RSRP) of the RS is determined. The reference signal (RS) uses a code that corresponds one-to-one with the PCI. This code can be used to obtain correlation and thus separate the cell from other cells. By deriving the RS code of the cell based on the PCI determined in step ST601, the RS can be detected, and the received power of the RS can be measured.

[0167] Next, in step ST603, the cell with the best RS reception quality is selected from one or more cells detected up to step ST602, for example, the cell with the highest RS reception power, i.e., the best cell.

[0168] Next, in step ST604, the PBCH of the best cell is received to obtain the broadcast information, i.e., the BCCH. The BCCH on the PBCH maps to the MIB (Master Information Block), which contains cell structure information. Therefore, by receiving the PBCH and obtaining the BCCH, the MIB can be obtained. Information in the MIB includes, for example, the DL (downlink) system bandwidth (also known as transmission bandwidth configuration), the number of transmit antennas, and the SFN (System Frame Number).

[0169] Next, in step ST605, the cell structure information based on the MIB is received from the DL-SCH of the cell, and SIB (System Information Block) 1 in the broadcast information BCCH is obtained. SIB1 contains information related to accessing the cell, information related to cell selection, and scheduling information for other SIBs (SIBk; k ≥ 2 integers). In addition, SIB1 also contains the Tracking Area Code (TAC).

[0170] Next, in step ST606, the communication terminal compares the TAC of SIB1 received in step ST605 with the TAC portion of the Tracking Area Identity (TAI) in the tracking area list already stored by the communication terminal. The tracking area list is also called the TAI list (TAI list). TAI is identification information used to identify the tracking area, consisting of the MCC (Mobile Country Code), MNC (Mobile Network Code), and TAC (Tracking Area Code). MCC is the country code. MNC is the network code. TAC is the tracking area code number.

[0171] If the comparison result obtained in step S606 is the same as the TAC received in step ST605, and it is also included in the tracking area list, then the communication terminal enters standby mode in that cell. If the comparison result is the same as the TAC received in step ST605, and it is not included in the tracking area list, then the communication terminal requests a change of tracking area from the core network (EPC) containing the MME, etc., through that cell to perform a TAU (Tracking Area Update).

[0172] The apparatus constituting the core network (hereinafter sometimes referred to as "core network-side apparatus") updates the tracking area list based on the TAU request signal and the identification number (UE-ID, etc.) of the communication terminal sent from the communication terminal. The core network-side apparatus sends the updated tracking area list to the communication terminal. The communication terminal rewrites (updates) its own TAC list based on the received tracking area list. Afterward, the communication terminal enters standby mode in the cell.

[0173] The widespread adoption of smartphones and tablets has led to an explosive growth in traffic volume using cellular wireless communication systems, raising concerns about a global shortage of wireless resources. To address this situation and improve frequency utilization efficiency, research has been conducted on cell miniaturization and promoting spatial separation.

[0174] In the existing cell structure, cells composed of eNBs have a wide coverage area. Previously, cells were constructed by utilizing the wide coverage area of ​​multiple cells consisting of multiple eNBs to cover a specific area.

[0175] When miniaturizing cells, cells composed of existing eNBs have a narrower coverage area compared to cells composed of existing eNBs. Therefore, similar to existing technologies, to cover a certain area, a large number of miniaturized eNBs are needed compared to existing eNBs.

[0176] In the following explanation, as with conventional eNBs, cells with larger coverage areas are referred to as "macrocells," and the eNBs that make up macrocells are referred to as "macro eNBs." Furthermore, as with cells that have undergone miniaturization, cells with smaller coverage areas are referred to as "small cells," and the eNBs that make up small cells are referred to as "small eNBs."

[0177] For example, a macro eNB can be a "wide area base station" as described in Non-Patent Document 7.

[0178] Small eNBs can be, for example, low-power nodes, local nodes, and hotspots. Furthermore, small eNBs can be pico eNBs constituting pico cells, femto eNBs constituting femto cells, HeNBs, RRHs (Remote Radio Heads), RRUs (Remote Radio Units), RREs (Remote Radio Equipment), or RNs (Relay Nodes). Additionally, small eNBs can also be the "Local Area Base Station" or "Home Base Station" described in Non-Patent Document 7.

[0179] Figure 7 This diagram illustrates the concept of a cell structure when macro eNBs and small eNBs are combined. Macro cells, composed of macro eNBs, have a relatively large coverage area 701. Small cells, composed of small eNBs, have a smaller coverage area 702 compared to the coverage area 701 of the macro eNBs (macro cells).

[0180] When multiple eNBs are mixed together, the coverage area of ​​a cell consisting of one eNB may be included in the coverage area of ​​a cell consisting of other eNBs. Figure 7 In the cell structure shown, as indicated by reference numerals "704" or "705", the coverage area 702 of a small cell consisting of small eNBs is sometimes included within the coverage area 701 of a macro cell consisting of macro eNBs.

[0181] Furthermore, as indicated by reference numeral "705", there are also cases where the coverage areas 702 of multiple, for example, two small cells are included within the coverage area 701 of a macrocell. A mobile terminal (UE) 703, for example, is included within the coverage area 702 of the small cells and communicates via the small cells.

[0182] In addition, Figure 7 In the structure of the cell shown, as indicated by reference numeral "706", the following situation will occur: the coverage area 701 of the macro cell composed of macro eNBs and the coverage area 702 of the small cell composed of small eNBs will overlap in a complex manner.

[0183] Furthermore, as indicated by reference numeral "707", the coverage area 701 of macro cells composed of macro eNBs and the coverage area 702 of small cells composed of small eNBs will not overlap.

[0184] Furthermore, as indicated by reference numeral "708", the following situation will also occur: the coverage area 702 of multiple small cells consisting of multiple small eNBs will be within the coverage area 701 of a macro cell consisting of a macro eNB.

[0185] As one of the services in NR, there exists URLLC (Ultra-Reliable, Low-Latency Communication) which requires low-latency and high-reliability communication. To simultaneously meet the requirements of low latency and high reliability, the 3GPP standards meeting agreed to support packet replication in the PDCP layer (see Non-Patent Document 11 (3GPP R2-1700672)). In NR, this packet replication is performed using a carrier aggregation (CA) architecture (see Non-Patent Document 9 (3GPP TR38.804 v14.0.0)).

[0186] In the aforementioned packet replication, the 3GPP meeting agreed that the logical channels through which replicated packets pass and the radio carriers used in the transmission of each packet are associated using RRC signaling settings (see Non-Patent Document 12 (Draft Report of 3GPP TSG RAN WG2 meeting #98, Hangzhou, China, 15-19 May, 2017)). Furthermore, regarding the control of packet replication activation / deactivation, the 3GPP meeting agreed to use MAC signaling for control (see Non-Patent Document 12).

[0187] It is recommended that the bearer identifier and the PDCP sequence number for starting / stopping packet replication be included in the MAC signaling controlling the start / stop of the aforementioned packet replication (see Non-Patent Document 13 (3GPP R2-1704578)). Furthermore, it is recommended that the logical channel identifier be included in this MAC signaling (see Non-Patent Document 14 (3GPP R2-1704660)).

[0188] Furthermore, in existing LTE systems, SCell activation / deactivation is supported (see Non-Patent Document 15 (3GPP TS36.321v14.3.0)). The base station controls the activation / deactivation of the SCell to the UE. This control uses MAC signaling. After receiving the MAC signaling, the UE starts / stops transmitting and receiving the SCell at a predetermined time.

[0189] Regarding the control of group replication and SCell, it is recommended to perform group replication without using group replication start control during SCell stop, or to start group replication by initiating SCell action (see Non-Patent Literature 16 (3GPP R2-1706867)). Furthermore, it is recommended to stop group replication during group replication action by a silent SCell stop based on the expiration of the SCell Deactivation Timer, or to continue group replication by allowing SCell action to continue (see Non-Patent Literature 16).

[0190] However, the details of the conflict handling regarding the packet copying and SCell control conflict shown in Non-Patent Document 16 are not disclosed. Furthermore, the actions taken when a conflict occurs between the MAC signaling for packet copying and the MAC signaling for SCell start / stop are not disclosed. Therefore, when such a conflict occurs, the UE is unclear on how to handle packet copying, which may lead to malfunctions.

[0191] Furthermore, including the MAC signaling controlling packet replication within the PDCP sequence number can cause problems if the MAC signaling from the base station to the UE fails to arrive and HARQ retransmission is repeated. Specifically, if the UE begins sending a PDCP PDU with that PDCP sequence number during the repeated HARQ retransmission, the UE will not know how to perform packet replication processing after successfully receiving the MAC signaling. Therefore, the UE may malfunction.

[0192] In this embodiment 1, a method for solving the above-mentioned problems is disclosed.

[0193] This establishes a priority between packet replication control and SCell control. The UE can prioritize SCell control over packet replication control. SCell control can be a MAC signaling signal to stop SCell. For example, a UE in the process of packet replication can stop packet replication by receiving a MAC signaling signal to stop SCell. This reduces power consumption in both the UE and the base station.

[0194] The cessation of packet replication mentioned above can refer to the cessation of transmission within the radio interval of the replicated packet, the disassociation of the logical channel and the transmission carrier, or a combination of both. The timing of these two actions can be simultaneous or different. In this invention, the subsequent actions can also be set to be the same.

[0195] Furthermore, in this invention, the start of packet replication can refer to the start of transmission within the radio interval of the replicated packet, the start of the association between the logical channel and the transmission carrier, or a combination of both. The timing of these two events can be simultaneous or different.

[0196] The UE can stop packet replication at the scheduled time when the SCell stops. This avoids control complexity within the UE. Alternatively, packet replication can be stopped when MAC signaling is received at the scheduled time of the SCell stop. The aforementioned "when MAC signaling is received" could, for example, mean immediately following the MAC signaling reception. This saves resources. Another example of timing to stop packet replication is when the entire PDCP PDU being transmitted at the MAC signaling reception time has been completed. This ensures the reliability of the PDCP PDU transmission and prevents buffering in the base station's RLC due to the inability to receive the entire PDCP PDU.

[0197] Alternatively, the base station can notify the UE of the timing of the stop of packet replication. This allows for flexible use of packet replication. The notification can be included in the MAC signaling for SCell stop. L1 / L2 signaling can also be used.

[0198] The difference between the above method and non-patent document 16 (3GPP R2-1706867) is that it is not a silent SCell stop, but an explicit SCell stop using MAC signaling.

[0199] The aforementioned stop timing can be a PDCP sequence number. In the base station's RLC, this prevents buffering caused by the inability to receive the entire PDCP PDU. Alternatively, the aforementioned stop timing can be a physical timing. By directly controlling radio resources, unwanted radio signal transmission and reception can be prevented. Physical timing can be, for example, a physical frame number, a subframe number, a timeslot number, a micro-timeslot number, or other information indicating timing. Alternatively, physical timing can also be the time up to the stop timing. In both the base station and the UE, appropriate processing accompanying the packet replication stop can be performed.

[0200] The UE can maintain the active / stopped state of packet replication. This state maintenance can be performed, for example, using flags for packet replication control. This state maintenance can also occur when a SCell is stopped. The UE can use the maintained state to initiate or stop packet replication. For example, this action or stop can be performed at the start of a SCell. For example, the packet replication operation can be restarted if a UE that was stopped during a packet replication operation receives MAC signaling again at the start of a SCell. Therefore, for example, the MAC signaling used in the packet replication operation / stop at the start of a SCell can be eliminated, thus reducing the MAC signaling load.

[0201] An initial value can be assigned to the action / stop status of packet replication. This initial value can be determined by a standard or notified to the UE by the base station. This notification can use RRC signaling, for example, dedicated RRC signaling.

[0202] Furthermore, regarding the restart of the aforementioned packet replication operation, the UE can determine the PDCP SN at the restart time. For example, after a SCell restarts, the packet replication operation can be restarted by the earliest PDCP PDU capable of transmission. This simplifies packet replication control within the UE. Alternatively, the base station can notify the UE of the timing of the packet replication restart. This notification can include a logical channel identifier or a PDCP sequence number. The notification can also represent physical timing information. This notification can be included in the MAC signaling for SCell start (restart) and sent by the base station to the UE.

[0203] The UE can update the packet replication action / stop status. This update can be performed using MAC signaling for packet replication action / stop. This update can be performed during SCell action or SCell stop. This allows for the decentralization of SCell action / stop and packet replication MAC signaling. Alternatively, the UE can choose not to update the packet replication action / stop status during SCell stop, thus avoiding the complexity of packet replication control at both the base station and the UE.

[0204] The UE can also choose not to maintain the active / stopped state of packet replication. This reduces the UE's storage usage. The UE can stop packet replication when a SCell action begins or restarts. This reduces radio resource usage. Alternatively, the UE can start packet replication when a SCell action begins or restarts. This ensures reliable communication at the start of a SCell action.

[0205] The action / stop status of the aforementioned group replication can be set for each bearer. This makes flexible use of group replication possible.

[0206] The UE can prioritize packet replication control over SCell control. SCell control can utilize MAC signaling that has been stopped by SCell. For example, even if the UE receives MAC signaling that has been stopped by SCell during a packet replication operation, it can still continue packet replication. This improves the reliability of packet replication from the UE.

[0207] The UE can notify the base station that the SCell stop is invalid. This notification can use MAC signaling or L1 / L2 signaling. The notification can also include a reason for the invalidation, such as "in progress of packet replication." The identifier of the logical channel involved in the packet replication operation can be notified along with the notification. The identifier of the bearer involved in the packet replication operation can also be notified. Thus, the base station can smoothly perform control after the SCell stop becomes invalid.

[0208] The priority of the aforementioned packet replication control and SCell control can be determined using the replicated packet. The UE can use information from the replicated packet to determine whether to stop the SCell. This enables flexible control based on the replicated packet.

[0209] As an example of using the priority order of replicated packets, the priority order can be determined by the division of SRBs and DRBs. For example, for SRBs, packet replication takes priority, while for DRBs, SCell control takes priority. This allows for flexible control based on the type of bearer.

[0210] Alternatively, priority can be determined for each bearer. For example, SRB0 and SRB1 can be prioritized for packet replication, while SBR2, SRB3, and DRB can be prioritized for SCell control. Furthermore, for example, for a DRB, one DRB can be prioritized for packet replication, while other DBRs can be prioritized for SCell control. This allows for further flexible control on a per-bearer basis.

[0211] The above priority order can be determined using standards, or it can be notified to the UE in advance by the base station using RRC signaling. The priority order can also be notified using MAC signaling. This allows for flexible control.

[0212] The UE can notify the base station that the SCell stop is invalid. When using packets with packet replication priority, this notification can, for example, be made when a packet replication-priority bearer uses the SCell. The method of notification and the information contained in the notification can be the same as described above. Thus, the base station can smoothly perform control after the SCell stop is invalid.

[0213] When using SCell for communication of multiple packets, a priority order can be assigned between packet replication control and SCell control. Multiple packets can be, for example, a combination of packets with priority for packet replication and packets with priority for SCell control.

[0214] In the above, packet replication can be prioritized. For example, during packet replication, the MAC signaling that caused SCell to stop can be invalidated. That is, packet replication can continue. This ensures the reliability of packets that prioritize replication. The UE can notify the base station that SCell stop is invalid. The method of notification and the information contained in the notification can be the same as described above. Thus, the base station can smoothly perform control after SCell stop is invalidated.

[0215] In the above, the UE and the base station can stop packet replication in a portion of the packets. This portion of the packets could be, for example, packets that prioritize SCell control. Packet replication of packets that prioritize replication can continue. This simplifies SCell control within the base station.

[0216] Alternatively, the UE and base station may choose not to stop packet duplication in the aforementioned portion of the packets. This ensures the reliability of packet communication.

[0217] In the above, the UE and base station can stop SCel1 when packet replication of packets with packet replication priority stops. This can reduce power consumption. The UE can notify the base station that SCel1 is stopped. This notification can also include a valid reason. This reason could be, for example, the cessation of packet replication of packets with packet replication priority. The notification can include information about the packet, such as the bearer identifier.

[0218] Alternatively, the UE and base station can choose not to stop SCell when packet replication of packets prioritizing packet replication stops. SCell control becomes easier.

[0219] As another example of prioritizing packet replication control over SCell control in the context of multiple packet communications, SCell control can be prioritized. For instance, during packet replication operations, the MAC signaling to stop SCell can be enabled. That is, SCell can be stopped, reducing power consumption.

[0220] As an example of prioritizing packet replication control over SCell control, the control to start packet replication can take precedence over the state where the SCell is stopped. That is, the UE can begin packet replication. This can be set as a start SCell action. The above-mentioned control to begin packet replication can use MAC signaling, ensuring reliability.

[0221] Alternatively, the state of a stopped SCell can take precedence over control of the start of packet replication. That is, the UE can keep the stopped SCell running.

[0222] The UE can notify the base station that packet replication is invalid. This notification can be made during or after the SCell is stopped. The notification can use MAC signaling or L1 / L2 signaling. The notification can include the logical channel identifier of the target channel. The notification can also include the reason for the invalid packet replication, such as "SCell is stopped." This allows the base station to perform appropriate and rapid control related to packet replication.

[0223] In the above description, a UE with invalid packet replication start control can use SCell start control to initiate packet replication. SCell start control can be MAC signaling indicating the start of SCell. During the packet replication start described above, the action / stop status of packet replication can be used. For example, the UE can use packet replication start control, such as packet replication start MAC signaling, to set this status to "action".

[0224] As another example of prioritizing packet replication control over SCell control, packet replication stop control can take precedence over the state in the SCell action. That is, the UE can stop the SCell using MAC signaling for packet replication stop. This SCell stop can occur when no other bearer is available for the UE to use that SCell to communicate with the base station. This reduces the UE's power consumption.

[0225] The base station can include information indicating the timing of packet replication start / stop in the MAC signaling controlling the start / stop of packet replication. This timing can be physical timing. By directly controlling radio resources, unwanted radio signal transmission and reception can be prevented. Physical timing can be, for example, a physical frame number, a subframe number, a timeslot number, a micro-timeslot number, or other information indicating timing. Alternatively, physical timing can also be the time up to the start / stop timing. Appropriate processing accompanying the cessation of packet replication can be performed in both the base station and the UE.

[0226] The UE can start / stop packet replication at the aforementioned start / stop timing. Alternatively, the UE can start / stop packet replication from the earliest PDCP PDU boundary after the aforementioned start / stop timing. This prevents discontinuity in UE transmission operations caused by the start / stop of packet replication. Furthermore, in the base station's RLC, buffering delays caused by the inability to receive the entire PDCP PDU can be prevented.

[0227] Other information indicating the start / stop timing mentioned above could be the PDCP sequence number. In the base station's RLC, this prevents buffering caused by the inability to receive the entire PDCP PDU.

[0228] The base station may also omit the information indicating the start / stop timing of packet replication from the MAC signaling controlling the start / stop of packet replication. The UE can start / stop packet replication immediately after receiving the MAC signaling. For example, the UE can start / stop packet replication from a timing immediately following the reception of the MAC signaling (e.g., subframe, time slot, micro-time slot, TTI). The start / stop timing of packet replication can be the next scheduling timing after the UE returns an ACK for the MAC signaling. Alternatively, the start / stop timing of packet replication can be the earliest PDCP PDU boundary after the MAC signaling reception timing in the UE. Alternatively, the UE can start / stop packet replication after a predetermined period from receiving the MAC signaling. The predetermined period can be determined in advance by a standard or notified to the UE by the base station. The predetermined period can also be notified to the UE separately by the base station. This separate notification can use RRC signaling. This reduces the signaling load associated with the start / stop timing of packet replication.

[0229] The base station can include information controlling the start / stop of SCells used in packet replication in the MAC signaling that controls the start / stop of packet replication. The UE can use this information to start / stop SCells. Therefore, the base station can flexibly control SCells that accompany packet replication.

[0230] Conversely, information controlling the start / stop of packet replication using this SCell for communication can also be included in the MAC signaling controlling the start / stop of the SCell. The UE can use this information to start / stop packet replication. Thus, the base station can flexibly control the SCell accompanying packet replication.

[0231] Alternatively, the MAC signaling for starting / stopping the control packet copy and the MAC signaling for starting / stopping the control SCell can be combined and set as a single MAC signaling. This single MAC signaling can then be configured as a new MAC signaling.

[0232] Alternatively, the base station can simultaneously transmit MAC signaling to control the start / stop of packet replication and MAC signaling to control the start / stop of SCell. The MAC signaling for both parties can be transmitted using the same transport block or different transport blocks. As an example of using different transport blocks, transmission could be performed using different carriers. This allows for rapid control of both SCell and packet replication. Alternatively, the MAC signaling to control the start / stop of packet replication and the MAC signaling to control the start / stop of SCell can be combined. This reduces the signaling load.

[0233] As another example of prioritizing packet replication control over SCell control, packet replication initiation control can take precedence over SCell action initiation control. For example, the UE can initiate SCell action at a packet replication initiation timer. The UE can then begin packet replication. This improves the reliability of packet transmission from the UE to the base station.

[0234] Alternatively, the control to initiate SCell action can take precedence over the control to initiate packet replication. For example, the UE can initiate packet replication at the start time of the SCell. This avoids the complexity of SCell control in both the base station and the UE.

[0235] The UE can notify the base station that the SCell has been invalidated. This notification can be sent, for example, if the SCell cannot be started. The notification can also include a reason for the invalidation. This reason could be, for example, a transceiver failure using the SCell's carrier frequency, or resource pressure on the SCell. The base station can use this notification to control the start / stop of other SCells. Thus, the base station can smoothly control the operation after an SCell has been invalidated.

[0236] As another example of prioritizing packet replication control over SCell control, the control to start packet replication can take precedence over the control to stop SCell. For example, the UE can start packet replication, thus disabling the control that stops SCell. This action can, for example, be performed when SCell is active and packet replication is stopped. This improves the reliability of packet transmission. The UE can notify the base station that the SCell stop is invalid. Through this notification, the base station can appropriately control radio resources.

[0237] Alternatively, the control to stop SCell can take precedence over the control to start packet replication. For example, the UE can stop SCell, thus invalidating the control to start packet replication. This conserves radio resources. The UE can notify the base station that packet replication is invalid. This notification allows the base station to appropriately determine the radio resources used in transmitting and receiving data with the UE.

[0238] As another example of prioritizing packet replication control over SCell control, packet replication stop control can take precedence over SCell stop control. For example, the UE can stop packet replication at a specified timing. For instance, if the SCell stop timing precedes the packet replication stop timing indicated by the MAC signaling, the UE can wait for the SCell action to stop until the packet replication stop timing is reached. This ensures the reliability of packet transmission.

[0239] Alternatively, the control to stop the SCell can take precedence over the control to stop packet replication. For example, the UE can stop packet replication at the SCell stop timer. For instance, if the SCell stop timer is before the packet replication stop timer indicated by the MAC signaling for packet replication stop, the UE can stop packet replication according to the stop timer of the SCell action. This ensures the reliability of packet transmission.

[0240] The UE can use MAC signaling to start / stop packet replication and MAC signaling to start / stop SCell to determine the actions of packet replication and SCell. For example, the UE can use the MAC signaling to start packet replication to determine the start of packet replication, or it can use both the MAC signaling to start packet replication and the MAC signaling to start SCell to determine the start of packet replication. The decision using the two-party MAC signaling can be a logical OR, a logical AND, or other logical operation. Alternatively, for example, the UE can use the MAC signaling to start SCell to determine the start of SCell, or it can use both the MAC signaling to start packet replication and the MAC signaling to start SCell to determine the start of SCell. The decision using the two-party MAC signaling can be a logical OR, a logical AND, or other logical operation. Therefore, flexible control of packet replication and SCell actions is possible.

[0241] In the above, flags related to packet replication and flags related to SCell actions can be used instead of the MAC signaling for starting / stopping packet replication and SCell. Flags related to packet replication can be, for example, the flags that maintain the action / stop state of packet replication as described above. Flags related to SCell actions can be, for example, flags whose values ​​toggle between action and stop based on the SCell start / stop MAC signaling. This allows for flexible and easy control of packet replication and SCell actions.

[0242] The UE can copy PDCP PDUs at the PDCP layer without relying on packet copying start / stop. The UE's PDCP layer can transmit the copied PDCP PDU to the RLC layer. The RLC layer can then transmit the PDCP PDU to the MAC layer. The UE can use RRC signaling from the base station to perform the above-mentioned copying and / or transmission processing. This RRC signaling can be signaling used to associate the logical channel through which each copied packet passes with the radio carrier used in the transmission of each packet. The UE can use RRC signaling from the base station to stop the above-mentioned copying and / or transmission. This RRC signaling can be signaling used to deassociate the logical channel through which each copied packet passes with the radio carrier used in the transmission of each packet. Thus, for example, the UE can quickly perform the transmission processing of copied packets at the start of packet copying.

[0243] The packet replication start / stop performed by the UE can occur at the correct timing of receiving the MAC signaling that controls the start / stop of packet replication. This correct timing of receiving the MAC signaling can be after the packet replication start / stop timing indicated by the MAC signaling. In the above context, "after" the packet replication start / stop timing indicated by the MAC signaling can refer to, for example, a HARQ retransmission. This timing can be specified, for example, by the PDCP sequence number, or it can be a physical timing. Physical timing can be, for example, a physical frame number, a subframe number, a time slot number, or a micro-time slot number.

[0244] The base station can pre-use multiple HARQ processes to send the MAC signaling to the UE, or it can use all HARQ processes. This improves the reliability of MAC signaling transmission and reception.

[0245] The base station can stop sending the MAC signaling to the UE. This MAC signaling transmission can be stopped, for example, when the UE receives an ACK for the MAC signaling that uses another HARQ process. This conserves radio resources.

[0246] The UE can use the initially received MAC signaling to start / stop packet replication. The initially received MAC signaling can refer, for example, to the first MAC signaling received among multiple HARQ processes. The UE can ignore or discard subsequent MAC signaling received after the second reception. This allows the UE to process the signaling quickly.

[0247] Alternatively, as described above, packet replication for the UE can be initiated retroactively. The UE can initiate packet replication until the packet replication start timing indicated by the MAC signaling. The UE can use L2 layer buffers, such as data stored in a PDCP layer buffer, to initiate packet replication. This ensures the reliability of packet replication.

[0248] Alternatively, the UE can perform packet replication retroactively until all traceable data is available. For example, the UE can perform this action if no data remains up to the packet replication start time indicated by the MAC signaling. The UE can also perform this action if data remains up to the packet replication start time indicated by the MAC signaling. This ensures the reliability of packet replication.

[0249] Alternatively, as described above, the UE's packet replication start / stop can be performed at the packet replication start / stop timing indicated by the MAC signaling. This packet replication start / stop timing can, for example, be set to the packet replication start / stop timing after a complete cycle of numbering. As an example, during the transmission of PDCP PDU with PDCP sequence number 7, when the UE receives MAC signaling from the base station indicating packet replication starting from PDCP PDU sequence number 5, the UE can start packet replication from the next PDCP PDU with sequence number 5 after a complete cycle of PDCP sequence numbering. This avoids design complexity in the UE.

[0250] Figure 8 This is a flowchart illustrating the actions taken when MAC signaling at the start of packet replication generates a HARQ retransmission, which is then received by the UE after a specified time interval. Figure 8 The sequence at the start of group replication is shown, but it does not apply to the stop of group replication. Furthermore, in Figure 8 In this context, PDCP sequence numbers are used as the specified timing, but physical timing can also be used. As physical timing, the timing described above can be used.

[0251] exist Figure 8 In step ST801, the base station determines the start of packet replication. In step ST802, the base station notifies the UE of the start of packet replication via MAC signaling. This signaling includes the uplink PDCP sequence number n in the UE indicating the start of packet replication. Figure 8 In step ST802, the UE fails to correctly receive the MAC signaling for the start of packet replication. In step ST803, the UE notifies the base station of a NACK. After receiving the NACK in step ST803, the base station retransmits the MAC signaling from step ST802 to the UE in step ST804. Figure 8In step ST804, the UE fails to correctly receive the MAC signaling for the start of packet replication. In step ST805, the UE notifies the base station of NACK again.

[0252] exist Figure 8 In step ST806 shown, the UE transmits PDCP PDUs with sequence numbers reaching n. The UE transmits the PDCP PDU with sequence number n to the base station without performing packet duplication.

[0253] exist Figure 8 In step ST807, the base station retransmits the MAC signaling to the UE for the second time. In step ST808, the UE notifies the base station of the ACK received in step ST807.

[0254] Figure 8 In step ST807, the UE that correctly receives the MAC signaling to start packet replication begins in step ST809. In steps ST810 and ST811, the UE sends the original packet and the replicated packet to the base station. In step ST812, the base station detects duplicate packets and deletes one of them.

[0255] The base station can configure the RLC layer for packet replication. This configuration can be implemented immediately after the packet replication start determination in the base station. Even when the time until the specified timing is short, the base station can quickly initiate packet replication.

[0256] The RLC layer settings for packet replication in the aforementioned base station can be configured after receiving an ACK from the UE for MAC signaling notifying the UE that packet replication has begun. The storage guarantee time in the RLC settings can be suppressed to the required minimum.

[0257] The PDCP layer of the base station can instruct the RLC layer to initialize the RLC layer. The RLC layer can use this instruction to initialize the RLC. This instruction can be performed, for example, when the reception of PDCP PDUs up to the PDCP sequence number that becomes the packet replication stop timing ends in the PDCP layer. This instruction can include, for example, an identifier of the RLC entity to be initialized, or an identifier of the logical channel using the RLC entity. The initialization can be, for example, the initialization of the buffer in the RLC PDU, the initialization of variables used in the RLC entity as described in Section 7.1 of Non-Patent Document 17 (TS36.322 v14.0.0), or a combination of both. Thus, PDCP PDUs up to the PDCP sequence number that becomes the timing can be reliably received by the PDCP layer of the CU.

[0258] The method described in Embodiment 1 can be applied to packet replication using only SCel1. This increases the flexibility of carrier selection in packet replication. Furthermore, the method described in Embodiment 1 can be applied to both C-Plane and U-Plane. This allows for the prevention of malfunctions during packet replication in both C-Plane and U-Plane.

[0259] In this embodiment 1, the base station can change the carrier associated with the logical channel in packet replication of the UE. That is, the base station can change the carrier used in the transmission of the logical channel in packet replication of the UE. This change can be performed, for example, by the MAC layer of the base station. This improves the tolerance of packet replication operations to changes in the radio wave environment.

[0260] The base station can notify the UE of changes to the carrier used in transmissions through the aforementioned logical channel. This notification can include information combining the logical channel with the carrier used. The base station can notify the UE using MAC signaling, enabling rapid and highly reliable notification based on HARQ control. Alternatively, the base station can notify the UE using L1 / L2 signaling, enabling even faster notification. Alternatively, the base station can notify the UE using RRC signaling, avoiding complexity in communication system design.

[0261] The UE can enable signaling sent from the base station that associates a logical channel with a transmitted carrier and / or modifies the association. This signaling can be RRC signaling, MAC signaling, or L1 / L2 signaling. The UE can enable the signaling if it contains a SCell not listed in the SCell list used by the UE. SCells included in the aforementioned SCell list can be, for example, SCells added or modified in the RRC connection reconfiguration signaling.

[0262] The UE can add SCells not currently listed in the SCell list. The UE can then notify the base station of the SCell information. This SCell information may include, for example, the SCell's Physical Cell ID (PCI), the SCell identifier (e.g., SCell Index), or a combination of both. The UE can assign the SCell identifier to the SCell. This SCell identifier can be the same as the one assigned by the base station, or it can be a provisional identifier. The provisional SCell identifier can be determined by a standard, or it can be pre-broadcast by the base station or separately notified to the UE. The base station can add the SCell to the UE's SCell list. The base station can also notify the UE of the added SCell information. The added SCell information may include the SCell identifier, the SCell's PCI, or both. The UE can replace the SCell identifier assigned by itself with the SCell identifier obtained from the base station notification.

[0263] The UE can use RRC signaling to notify the base station of information for that SCell. For example, if the signaling sent from the base station that associates the logical channel with the transmitted carrier is RRC signaling, the notification of this information can be performed using RRC signaling. By using the same type of signaling to notify both the signaling and the notification, the processing involved in SCell control in the base station becomes easier.

[0264] Alternatively, the UE can use MAC signaling to notify the base station of information about that SCell. For example, if the signaling sent from the base station that associates the logical channel with the transmitted carrier is MAC signaling, the notification of this information can be made using MAC signaling. In addition to achieving the same effect as described above, this also allows for rapid notification.

[0265] Alternatively, the UE can use L1 / L2 signaling to notify the base station of information for that SCell. For example, if the signaling sent from the base station that associates the logical channel with the transmit carrier is L1 / L2 signaling, the information can be notified using L1 / L2 signaling. This allows for faster notification.

[0266] The UE can invalidate signaling sent from the base station that associates a logical channel with a transmit carrier and / or modifies the association. This signaling can be the same as described above. The UE can also invalidate signaling if it contains an SCell not listed in the SCell list used by the UE. The same applies to SCells not listed in the SCell list.

[0267] The UE can perform packet replication with the original packet replication settings. Alternatively, the UE can stop packet replication. Stopping packet replication can apply to all packets that the UE is replicating, or to the packets involved in the signaling. Alternatively, the UE can delete the packet replication settings for the packets involved in the signaling.

[0268] The UE can notify the base station that the signaling is invalid. This notification can include the reason for the invalidity. For example, the reason could be that the SCell notified by the signaling does not exist in the SCell list used by the UE. Furthermore, the signaling can also include SCell information. SCell information could be, for example, information about a SCell not existing in the UE's SCell list, such as the SCell's PCI. This simplifies the control of SCells within the base station.

[0269] The UE can use RRC signaling in this notification. For example, if the signaling sent from the base station that associates the logical channel with the transmitted carrier is RRC signaling, the UE can use RRC signaling to make the notification. By using the same type of signaling to notify both the signaling and the notification, the processing involved in SCel1 control in the base station becomes easier.

[0270] Alternatively, the UE can use MAC signaling in the notification. For example, if the signaling sent from the base station that associates the logical channel with the transmitted carrier is MAC signaling, the notification can be made using MAC signaling. In addition to achieving the same effect as described above, this also allows for rapid notification.

[0271] Alternatively, the UE can use L1 / L2 signaling in this notification. For example, if the signaling sent from the base station that associates the logical channel with the transmitted carrier is L1 / L2 signaling, the notification can be made using L1 / L2 signaling. This allows for faster notification.

[0272] The base station can send signaling to the UE to append the SCell to the UE's SCell usage list. The base station can also send signaling to the UE to associate a logical channel with a transmit carrier. Packet duplication using this SCell is possible. The base station can send signaling to both parties simultaneously to the UE, or at different time intervals. The signaling from both parties can also be combined into a single signaling message.

[0273] According to this embodiment 1, malfunctions of the UE can be prevented when conflicts arise between packet replication and SCell control. Furthermore, malfunctions of the UE can be prevented when the timing of the packet replication start / stop MAC signaling from the base station is after the timing indicated by the MAC signaling.

[0274] Variation 1 of Implementation Method 1.

[0275] Packet replication using CA can be applied to NR base stations (gNBs) that are separated into two units.

[0276] In 3GPP, it was proposed to separate the NR base station (hereinafter sometimes referred to as gNB) into two units (see Non-Patent Document 7). These two units are referred to as CU (Central Unit) and DU (Distributed Unit). Regarding the functional division of CU and DU when CU-DU are separated, CU has PDCP, and DU has RLC, MAC and PHY (see Non-Patent Document 18 (3GPP R3-171412)).

[0277] Figure 9 This is a diagram illustrating the protocol structure used in packet replication between a gNB and a UE that has undergone CU-DU separation, employing CA.

[0278] The new AS layer 1022 in UE1014 receives packets from the upper layer, such as an application or RRC, to generate PDCP SDU and transmit PDCP 1021.

[0279] PDCP1021 uses the PDCP SDU to generate a PDCP PDU and copies the PDCP PDU, sending each PDCP PDU to RLC1019 and RLC1020. RLC1019 and RLC1020 use each PDCP PDU to generate an RLC PDU, which is then sent to MAC1016.

[0280] MAC1016 uses the RLC PDU received by RLC1019 to generate transport channel data and sends it to HARQ1015 for Cell #1. MAC1016 uses the RLC PDU received by RLC1020 to generate transport channel data and sends it to HARQ1018 for Cell #2.

[0281] HARQ1015 transmits transport channel data generated using the RLC PDU from RLC1019 to PHY1014. PHY1014 encodes and modulates the transport channel data and transmits it as a radio signal to DU1006 using Cell #1. HARQ1018 transmits transport channel data generated using the RLC PDU from RLC1020 to PHY1017. PHY1017 encodes and modulates the transport channel data and transmits it as a radio signal to DU1006 using Cell #2.

[0282] In DU1006, PHY1011 receives the signal from cell #1, demodulates and decodes it, and sends it as transmission channel data to HARQ1010. HARQ1010 then transmits the transmission channel data to MAC1009. PHY1013 receives the signal from cell #2, demodulates and decodes it, and sends it as transmission channel data to HARQ1012. HARQ1012 then transmits the transmission channel data to MAC1009.

[0283] MAC1009 uses data from each transmission channel of HARQ1010 and 1012 to generate RLC PDUs, which are then transmitted to RLC1007 and RLC1008 respectively. RLC1007 uses the RLC PDUs to generate PDCP PDUs and transmits them to PDCP1003 of CU1001 via CU-DU interface 1004. RLC1008 uses the RLC PDUs to generate PDCP PDUs and transmits them to PDCP1003 of CU1001 via CU-DU interface 1004.

[0284] In CU1001, PDCP1003 uses each PDCP PDU from RLC1007 and 1008 to perform duplicate detection and delete duplicate PDCP PDUs. PDCP1003 uses the original, i.e., the PDCP PDUs that have not been deleted, to generate PDCP SDUs and transmits them to the New AS Layer 1002.

[0285] However, in gNBs with CU-DU separation, it is unclear which of the CU and DU should be responsible for determining packet replication. Furthermore, the signaling between the CU and DU during packet replication is not specified. Therefore, the following problem exists: the UE cannot perform packet replication during communication with a gNB that has CU-DU separation.

[0286] The above-mentioned problems are solved in this modified example 1 of embodiment 1.

[0287] The DU determines when to start group replication. This can also be determined by the MAC layer.

[0288] The DU can use uplink signal measurement results to determine the start of packet replication. Uplink signals can be, for example, SRS (Self-Rating Signal), and uplink error rates can be, for example, BER (Breakpoint Error Rate) or BLER (Breakpoint Error Rate). Alternatively, the uplink data transmission size can be used to determine the start of packet replication. The uplink data transmission size can be, for example, the uplink grant sent from the DU to the UE, or the BSR (Buffer Status Report) received from the UE. Alternatively, the load of each cell can be used to determine the start of packet replication. The load of each cell can be, for example, the scheduling status to other UEs. This allows for optimization of overall system communication.

[0289] The above content, including the measurement results of the uplink signal, the size of the uplink transmitted data, and the load of each cell, is disclosed in Non-Patent Document 19 (see R2-1706716). However, the present invention differs from Non-Patent Document 19 in that it discloses specific examples of the measurement results of the uplink signal, the size of the uplink signal data, and the load of each cell.

[0290] The DU can send a notification to the CU indicating the start of packet replication. The CU can send a response to the DU in response to this notification. This response can contain information related to the timing of the start of packet replication. Similar to Embodiment 1, this timing-related information can be a PDCP sequence number or information related to physical timing. The PDCP sequence number is information related to the sequence number of the PDCP PDUs received by the CU's PDCP layer; for example, it can be the largest sequence number among the PDCP PDUs. This allows for rapid notification of information related to the PDCP sequence number from the CU. Alternatively, the CU can notify the DU of the PDCP sequence number at which the UE begins packet replication. This reduces the processing load in the DU.

[0291] The DU can notify the UE of the start of packet replication via MAC signaling. Similar to Implementation 1, this MAC signaling can include information related to the timing of the start of packet replication.

[0292] The CU's response to the DU may not include information related to the timing of initiating packet replication. Similarly, the MAC signaling from the DU to the UE may not include information related to this timing.

[0293] The processing in the UE can be the same as in Implementation 1. This avoids the complexity of packet replication from the UE to the base station.

[0294] The DU can choose not to send a notification of the start of packet replication to the CU. The CU can also choose not to send a response to the notification of the start of packet replication to the DU. This reduces the signaling load between the CU and DU.

[0295] Figure 10 This is a flowchart of the group replication process when DU determines that group replication has begun. Figure 10 In the example shown, an example of using PDCP sequential number n is illustrated as the timing for the start of group replication.

[0296] exist Figure 10 In step ST1101, the DU determines the start of group replication. In step ST1102, the DU notifies the CU of the start of group replication. In step ST1103, the CU notifies the DU of its agreement to start group replication. In step ST1103, information related to the timing of the start of group replication may be provided. Figure 10 In the example, as this information, the PDCP sequence number n is notified from the CU to the DU.

[0297] exist Figure 10 In this process, the DU may not notify the CU of step ST1102. Regarding step ST1103, it may not include information related to the timing of the packet replication start. Alternatively, the CU may not notify the DU of step ST1103. This can reduce the signaling volume in the CU-DU interface.

[0298] exist Figure 10 In step ST1104, the DU notifies the UE of the MAC signaling indicating the start of packet replication. In step ST1104, information related to the timing of the packet replication start can be provided. Figure 10 In the example, as this information, the DU notifies the UE of the PDCP sequence number n. In step ST1105, the UE notifies the DU of the ACK for step ST1104.

[0299] exist Figure 10 In step ST1106, the UE begins packet copying. In steps ST1107 and ST1108, the UE sends the original packets and the copied packets to the DU. In steps ST1109 and ST1110, the DU sends the PDCP PDUs received in steps ST1107 and ST1108, respectively, to the CU. In step ST1111, the CU detects duplicate packets and deletes one of them.

[0300] In this variation 1 of implementation method 1, the CU can determine the start of group replication. This determination can be made by the RRC layer or the PDCP layer.

[0301] The DU can notify the CU of the information required to determine the start of packet replication. This information can be, as described above, the information required by the DU to determine the start of packet replication. The difference between this invention and non-patent document 19 (3GPP R2-1706716) is that the DU notifies the CU of this information.

[0302] The CU can notify the DU whether packet replication has been implemented. This notification can include information related to the timing of starting packet replication. The information related to the timing of starting packet replication can be the same as the information included in the response sent by the CU to the DU for the packet replication start notification. This can reduce the processing load used by the UE to determine the timing of starting packet replication.

[0303] The DU can notify the UE of the start of packet replication via MAC signaling. Similar to Implementation 1, this MAC signaling can include information related to the timing of the start of packet replication.

[0304] The CU's response to the DU may not include information related to the timing of initiating packet replication. Similarly, the MAC signaling from the DU to the UE may not include information related to this timing.

[0305] The processing in the UE can be the same as in Implementation 1. This avoids the complexity of packet replication from the UE to the base station.

[0306] Figure 11 This is a flowchart of the group replication process when the CU determines that group replication has begun. Figure 11 In the example shown, an example of using PDCP sequential number n is illustrated as the timing for the start of group replication. Figure 11 The process shown includes and Figure 10 The process shown has the same steps, therefore, the same step numbers are added to the same steps, and common descriptions are omitted.

[0307] exist Figure 11 In step ST1201, the DU notifies the CU of information used by the CU in determining the start of packet replication. In step ST1202, the CU determines the start of packet replication. In step ST1203, the CU notifies the DU of the start of packet replication. In step ST1203, information related to the timing of the start of packet replication may be provided. Figure 11 In the example, as this information, the PDCP sequence number n is notified from the CU to the DU.

[0308] Figure 11 The steps ST1104 to ST1111 shown are related to Figure 10 The same process applies, therefore explanation is omitted.

[0309] Similar to Embodiment 1, the packet replication start / stop performed by the UE can be performed at the timing of correctly receiving the MAC signaling controlling the start / stop of packet replication. The timing of correctly receiving the MAC signaling can be after the packet replication start / stop timing indicated by the MAC signaling. In the above context, "after the packet replication start / stop timing indicated by the MAC signaling" could refer to, for example, a HARQ retransmission. The base station's actions in Embodiment 1 can be interpreted as actions in the DU and implemented accordingly. The same effects as in Embodiment 1 can be obtained.

[0310] In the above description, similar to Embodiment 1, the packet replication of the UE can be started retroactively. Alternatively, the packet replication start / stop timing of the UE can be set to the packet replication timing indicated by the MAC signaling controlling the start / stop of packet replication, such as the packet replication start / stop timing after a number cycle. The same effect as Embodiment 1 can be obtained.

[0311] Figure 12 This is a flowchart illustrating the actions taken by the UE in communication between the UE and the gNB that has undergone CU-DU separation, where the MAC signaling at the start of packet replication is retransmitted due to a HARQ and is received by the UE after a specified time interval. Figure 12 An example is shown where DU determines when to begin grouped replication. Figure 12 The process shown includes and Figure 8 , Figure 10 The process shown has the same steps, therefore, the same step numbers are added to the same steps, and common descriptions are omitted.

[0312] Figure 12 The steps ST1101 to ST1104 shown are... Figure 10 Since they are the same, the explanation is omitted.

[0313] Figure 12 The steps ST1301 to ST1304 shown are in Figure 8 The communication target from the UE is obtained by replacing the base station with a DU in steps ST803-ST806. In step ST1305, the DU transmits the PDCP PDU with PDCP sequence number n received in step ST1304 to the CU. Steps ST1307-ST1308 are... Figure 8 The communication target from the UE is obtained by replacing the base station with DU in steps ST807 to ST808 shown.

[0314] Figure 12 The steps ST1106 to ST1111 shown are... Figure 10 Since they are the same, the explanation is omitted.

[0315] In this variation 1 of implementation 1, the DU can notify the CU of ACK / NACK information for MAC signaling indicating the start of packet replication, which is received from the UE. In the CU, for example, system control can be easily performed when irregularities such as exceeding the HARQ retransmission limit occur.

[0316] In the above, the DU can only notify the ACK information received from the UE, reducing the signaling volume at the CU-DU interface. Alternatively, it can only notify the NACK information, enabling rapid system control within the CU. It can also notify both ACK and NACK information, allowing the CU to quickly obtain overall system information. Alternatively, the ACK information notified from the DU to the UE can be only the initially received ACK. The initially received ACK can be used, for example, when multiple HARQ processes are used to communicate the aforementioned MAC signaling. This further reduces the signaling volume at the CU-DU interface.

[0317] Even when packet replication is stopped, the method shown in this variant 1 of embodiment 1 can still be used. In a base station where CU-DU separation has been implemented, both packet replication start / stop can be implemented.

[0318] The DU can configure the RLC layer for packet replication. This configuration can be implemented immediately after the packet replication start determination in the DU. Alternatively, the configuration can be implemented immediately after the CU notifies the DU of the packet replication start. Even when the time until the specified timing is short, the DU can quickly begin the packet replication process.

[0319] The RLC layer settings for packet replication in the aforementioned DU can be configured after receiving an ACK from the UE for MAC signaling notifying the UE that packet replication has begun. This allows the storage assurance time in the RLC settings to be minimized to the required minimum.

[0320] The CU can instruct the DU to initialize the RLC layer. The DU can use this instruction to initialize the RLC. This instruction can be performed, for example, when the reception of PDCP PDUs up to the PDCP sequence number that becomes the packet replication stop timing ends in the CU's PDCP layer. This instruction can include, for example, an identifier of the RLC entity to be initialized, or an identifier of the logical channel using that RLC entity. The initialization can be, for example, the initialization of the buffer in the RLC PDU, the initialization of variables used in the RLC entity as described in Section 7.1 of Non-Patent Document 17 (TS36.322 v14.0.0), or a combination of both. Thus, PDCP PDUs up to the PDCP sequence number that becomes the timing can be reliably received through the CU's PDCP layer.

[0321] Similar to Embodiment 1, in this variation 1 of Embodiment 1, the DU can change the carrier associated with the logical channel in packet replication of the UE. This change can be performed, for example, by the MAC layer of the DU. This improves the resilience of packet replication operations to changes in the radio environment.

[0322] Similar to Implementation 1, the DU can notify the UE of changes to the carrier used in the transmission of the aforementioned logical channel. This notification may include information combining the logical channel with the carrier used. Furthermore, the DU can notify the UE of this notification via MAC signaling or L1 / L2 signaling. Rapid notification from the DU to the UE becomes possible.

[0323] In the above, the DU can notify the CU of changes to the carrier used in the transmission of the aforementioned logical channel. This notification from the DU to the CU can occur before, simultaneously with, or after the notification from the DU to the UE. The information contained in this notification can be the same as the information contained in the notification from the DU to the UE. The notification from the DU to the CU can use a CU-DU inter-interface, such as the F1 interface. The CU can notify the DU of the carrier change by agreeing or disagreeing. This agreement or disagreement notification can also use a CU-DU inter-interface, such as the F1 interface. The DU can use this agreement or disagreement notification to notify the DU of the carrier change used in the logical channel transmission from the DU to the UE. Alternatively, the DU can change to another carrier, revert to the original carrier, or perform other processing. Thus, the CU can efficiently control the entire communication system.

[0324] The carrier change associated with the logical channel in packet replication can be performed by the CU. The CU can notify the UE of the carrier change using RRC signaling. Alternatively, the CU can notify the DU of the carrier change. The information contained in this notification can be the same as the information contained in the notification from the DU to the UE described above. The DU can send this notification to the UE. This transmission can use MAC signaling or L1 / L2 signaling. Thus, the CU can efficiently control the entire communication system.

[0325] Similar to Implementation 1, the UE can enable signaling sent from the base station that associates a logical channel with a transmit carrier. The UE can enable the signaling if it includes a SCell not listed in the SCell inventory used by the UE. The UE's actions when this signaling is enabled can be the same as in Implementation 1, achieving the same effect as in Implementation 1.

[0326] Similar to Implementation 1, the UE can notify the DU of information about SCells not listed in the above SCell list. The DU can then notify the CU of this information. The notification to the CU can be performed using the CU-DU interface. The information included in the notification to the CU can be the same as in Implementation 1.

[0327] Similar to Implementation 1, the UE can invalidate the signaling sent from the base station that associates a logical channel with a transmit carrier. The UE can invalidate the signaling if it contains a SCell not listed in the SCell inventory used by the UE. The UE's actions when this signaling is invalidated can be the same as in Implementation 1, achieving the same effect as in Implementation 1.

[0328] Similar to Implementation 1, the UE can notify the DU that the signaling is invalid. The DU can then notify the CU of this information. The notification to the CU can be made using the CU-DU interface. The information included in the notification to the CU can be the same as in Implementation 1.

[0329] According to this variation 1 of embodiment 1, even a gNB with separated CU-DU can receive uplink packet copies, thus improving the reliability of packet transmission.

[0330] Implementation Method 2.

[0331] As another method of grouped replication described in Embodiment 1, MC (including DC) was used (refer to Non-Patent Document 9 (3GPP TR 38.804v14.0.0)).

[0332] However, the switching between packet replication using CA and packet replication using DC is not disclosed. Therefore, for example, when a UE with packet replication using CA set to be active moves to the cell, it cannot switch to packet replication using DC, resulting in a problem that cannot ensure the reliability of communication.

[0333] In this second embodiment, a method for solving the above-mentioned problems is disclosed.

[0334] Assume that the base station and UE can switch between packet replication using CA and packet replication using DC.

[0335] In the above, the base station and UE can switch bearer structures. The switching of bearer structures can use the mode shown in Non-Patent Document 22 (R2-1704001). For example, it can switch from MCG (Master Cell Group) bearer to MCG fork bearer. It can switch from packet replication using CA to packet replication using DC. The reverse mode can also be used. It can switch from packet replication using DC to packet replication using CA.

[0336] As other examples, a switch can be made from SCG (Secondary Cell Group) bearer to SCG fork bearer. A switch can also be made from packet replication using CA to packet replication using DC. The reverse mode can also be used. A switch can be made from packet replication using DC to packet replication using CA.

[0337] Modes not shown in Non-Patent Document 22 can also be used. For example, it is possible to switch from SCG bearer to forking one SCG into other SCGs as the bearer for the anchor base station (hereinafter, sometimes referred to as SCG-only forked bearer). The reverse mode can also be used. In packet replication using DC, the flexibility of base station selection can be improved.

[0338] As other examples, the signaling load can be reduced by switching from MCG bearer to SCG fork bearer, or to SCG-only fork bearer. The reverse mode can also be used. By simultaneously switching between base stations using the PDCP layer (i.e., anchor base stations) and the packet replication structure, signaling load can be reduced.

[0339] As another example, switching from MCG fork bearer to SCG bearer can be performed. The reverse can also be used. By simultaneously switching between base stations using the PDCP layer (i.e., anchor base stations) and the packet replication structure, signaling load can be reduced.

[0340] The base station and the UE can switch logical channels. For example, as described above, the base station and the UE can maintain one of the two logical channels used in packet replication. The maintained logical channel could be, for example, a logical channel used during a switch from packet replication using CA to packet replication using DC, where wireless communication between the base station and the UE can continue even after the packet replication switch. By maintaining a logical channel, continuity in communication using that logical channel can be ensured.

[0341] The above can be used to free up another logical channel, reducing storage usage in the base station and UE. Alternatively, another logical channel can be maintained. For example, this maintained logical channel can be used when packet replication restarts due to a handover of packet replication, reducing signaling load during the handover.

[0342] As another example, the base station and UE can release both logical channels used in packet replication. The base station and UE can also configure new logical channels. This allows for flexible implementation of resource settings during packet replication handover.

[0343] Alternatively, the logical channel can be left unchanged. The base station and UE can maintain the two logical channels used in packet replication. In the above scenario, the base station can be switched while maintaining the use of only one logical channel, which can reduce signaling load.

[0344] In the above logical channel maintenance, the base station and UE can maintain the RLC layer, or the MAC layer, or both the RLC and MAC layers. This can reduce the signaling load associated with packet duplication.

[0345] Alternatively, the RLC layer can be released. The MAC layer can also be released. Both the RLC and MAC layers can be released. This allows for flexible implementation of RLC and / or MAC settings.

[0346] In the above logical channel release, the base station and UE can release the RLC layer, or the MAC layer, or both the RLC and MAC layers. This can reduce storage usage.

[0347] The base station and UE can release the mapping between logical channels and carriers used in packet replication. This release can be used during handovers from packet replication using CA to packet replication using DC. This improves carrier usage flexibility during handovers from CA to DC.

[0348] The base station and the UE can specify the mapping between logical channels and carriers used in packet replication. This specification can be used during handovers from packet replication using DC to packet replication using CA, ensuring a smooth handover from DC to CA.

[0349] The base station and UE can set the packet replication action to "activated". This packet replication action can be set to occur immediately before the packet replication handover, immediately after the packet replication handover, or as an action performed by both parties before and after the packet replication handover. This prevents interruption of data transmission and reception before and after packet replication.

[0350] The base station and UE can set the packet copying action to deactivated. This packet copying action can be set to occur immediately before the packet copying handover, or it can be set to occur shortly after the packet copying handover, or it can be an action performed by both parties before and after the packet copying handover. This conserves radio resources before and after packet copying.

[0351] The base station and UE can maintain a packet replication active / suspended state. This state can be maintained before and after a packet replication handover. For example, if packet replication is active before the handover, it can be set to active again even after the handover. This ensures smooth transmission and reception of user data and / or control data.

[0352] The packet replication operation accompanying the handover can be predetermined by a standard. Alternatively, the base station can notify the UE of this operation. This notification can use RRC signaling, MAC signaling, or L1 / L2 signaling. The aforementioned RRC signaling can be, for example, the RRC signaling used during packet replication handover. The aforementioned MAC signaling can be, for example, the MAC signaling for starting / stopping packet replication described in Embodiment 1 and its variation 1. This improves the flexibility of packet replication handover operations.

[0353] In this second embodiment, packet replication handover can be initiated by either the primary base station or the secondary base station. Alternatively, packet replication handover can also be initiated by the anchor base station. By initiating it from the anchor base station, packet replication handover can be applied to the aforementioned SCG-only fork bearer.

[0354] Figure 13 This is a flowchart illustrating the handover scenario where packet replication is initiated by the primary base station. Figure 13 An example of switching from packet replication using a CA in an SCG bearer to packet replication using a DC in an SCG fork bearer is shown. Figure 13 In this context, MeNB represents the eNB acting as the primary base station, and SgNB represents the gNB acting as the secondary base station.

[0355] exist Figure 13 In step ST2001, the UE performs packet duplication using CA. In steps ST2002 and ST2003, the UE transmits the duplicated packets to the SgNB using different carriers. In step ST2004, the SgNB detects and deletes duplicate packets.

[0356] exist Figure 13In step ST2005, the MeNB sends an SgNB Modification Request to the SgNB. This SgNB Modification Request may contain information indicating the type of packet replication. This information may, for example, be included in the SgNB Modification Request in the form of an SCG-ConfigInfo file.

[0357] exist Figure 13 In step ST2006 shown, the SgNB sends an SgNB Modification Request Acknowledgement response to the MeNB. This SgNB Modification Request Acknowledgement response may contain information related to changes in the UE's RRC parameters. This information related to changes in the UE's RRC parameters may, for example, be included in the SgNB Modification Request Acknowledgement response in the form of an SCG-Config file.

[0358] Figure 13 The example shown illustrates a response confirming an SgNB modification request, but a rejection response is also possible. For instance, the SgNB can send an SgNB Modification Request Reject to the MeNB. This SgNB Modification Request Rejection can include a reason for the rejection. Alternatively, it can include bearer information, such as the bearer's identifier. This bearer can be the reason the SgNB rejected the request. The MeNB can use this rejection response to, for example, change configuration parameters and notify the SgNB of the modification request again. Thus, for example, the MeNB's handling of situations where the SgNB cannot fulfill a request from the MeNB can be smoothly implemented.

[0359] exist Figure 13 In step ST2007, the MeNB notifies the UE of RRC connection reconfiguration. The UE uses step ST2007 to perform packet replication handover and related RRC parameter changes. In step ST2008, the UE notifies the MeNB that RRC connection reconfiguration is complete. In step ST2009, the MeNB notifies the SgNB that SgNB reconfiguration is complete.

[0360] exist Figure 13In step ST2010, the UE performs packet duplication using DC. In steps ST2011 and ST2012, the UE sends the duplicated packets to the MeNB and SgNB, respectively. In step ST2013, the MeNB sends the packets received in step ST2011 to the SgNB. In step ST2014, the SgNB detects and deletes duplicate packets.

[0361] exist Figure 13 The example shown illustrates a primary base station (eNB) and a secondary base station (gNB), but the primary base station can also be a gNB. Furthermore, the secondary base station can also be an eNB. Both the primary and secondary base stations can be gNBs or both can be eNBs.

[0362] Figure 14 This is a flowchart illustrating a handover scenario where packet replication is initiated by the secondary base station. Figure 14 An example of switching from packet replication using a CA in an SCG bearer to packet replication using a DC in an SCG fork bearer is shown. Figure 14 In this context, MeNB represents the eNB acting as the primary base station, and SgNB represents the gNB acting as the secondary base station. Figure 14 Includes and Figure 13 The process shown has the same steps, therefore, the same step numbers are added to the same steps, and common descriptions are omitted.

[0363] exist Figure 14 In step ST2101, the SgNB sends a notification to the MeNB indicating the existence of an SgNB Modification Required. This notification may contain information indicating the type of packet replication. It may also contain information related to changes in the UE's RRC parameters. Information indicating the type of packet replication and / or information related to changes in the UE's RRC parameters may, for example, be included in the notification in the form of an SCG-Config file.

[0364] Figure 14 The example illustrates how the MeNB can acknowledge an SgNB change request from the SgNB, but can also reject it. For instance, the MeNB can send an SgNB Modification Refuse to the SgNB. This SgNB Modification Refuse can include a reason for the rejection. Alternatively, it can include bearer information, such as the bearer's identifier. The aforementioned bearer can be the bearer that is the reason the MeNB rejects the request. The SgNB can, for example, use the rejection response to change configuration parameters and notify again of the existence of the SgNB change request. Thus, for example, the SgNB's handling of situations where the MeNB cannot fulfill a request from the SgNB can be smoothly implemented.

[0365] exist Figure 14 In step ST2102 shown, the MeNB notifies the SgNB of the change confirmation (SgNB ModificationConfirm).

[0366] exist Figure 14 In, with Figure 13 Similarly, the primary base station can be a gNB. Additionally, the secondary base station can also be an eNB. Both the primary and secondary base stations can be gNBs or both can be eNBs.

[0367] The SgNB change request sent from the primary base station to the secondary base station may include information indicating the type of packet replication. The type of packet replication may be, for example, packet replication using a CA or packet replication using a DC. The information indicating the type of packet replication may also indicate the type of packet replication after the handover.

[0368] The primary base station can include information indicating the type of packet replication in the additional bearer configuration settings. These additional bearer configuration settings can, for example, be equivalent to the settings in the E-RABs To Be Added Item section 9.1.3.5 of Non-Patent Document 23 (3GPP TS36.423v14.3.0) for SCG bearers and split bearers. By including this information in the additional bearer configuration settings, a handover can be made, for example, from packet replication using CA in an MCG bearer to packet replication using DC.

[0369] As another example, the primary base station may include information indicating the type of packet replication in the modified bearer configuration settings. The modified bearer configuration settings may, for example, be equivalent to the settings in the E-RABs To Be Modified Item in Section 9.1.3.5 of Non-Patent Document 23 (3GPP TS36.423 v14.3.0), specifically the settings for the SCG bearer and split bearer. By including this information in the modified bearer configuration settings, a switch can be made, for example, from packet replication using the CA in the SCG bearer to packet replication using the DC in the SCG split bearer.

[0370] As another example, the primary base station can include information indicating the type of packet replication in the bearer release configuration. The bearer release configuration can, for example, be equivalent to the configuration items in the E-RABs To Be Released Item of Section 9.1.3.5 of Non-Patent Document 23 (3GPP TS36.423 v14.3.0), specifically the SCG bearer and split bearer configurations. By including this information in the bearer release configuration, a switch can be made, for example, from packet replication using DC to packet replication using CA in the MCG bearer.

[0371] The secondary base station can use information indicating the type of packet replication to determine whether packet replication has occurred. For example, if this information is not included, the secondary base station can determine that packet replication is not occurring. Alternatively, a value indicating that packet replication is not occurring can be appended to this information. Thus, the presence or absence of packet replication can be processed aggregatedly, thereby reducing processing load.

[0372] In the above description, as an alternative to the E-RABs To Be Added Item, settings related to the added PDU session or settings related to the added radio bearer can be used. New settings related to the added PDU session and / or settings related to the added radio bearer can be added. The same applies to the E-RABs To Be Modified Item and E-RABs To Be Released Item. When the primary base station is a MgNB, the method shown in Embodiment 2 can be applied. Furthermore, flexible settings can be made for each PDU session and each radio bearer.

[0373] In the above content, the settings in the fork bearer can be settings in the MCG fork bearer, settings in the SCG fork bearer, or settings in both. The settings in the fork bearer can include information indicating the type of fork bearer. The type of fork bearer can be an MCG fork bearer, an SCG fork bearer, or an SCG-only fork bearer. This avoids the complexity of design in the inter-base station interface.

[0374] Alternatively, the settings in the forked bearers mentioned above can be divided into (a) settings in the MCG forked bearers, (b) settings in the SCG forked bearers, and (c) settings in the SCG-only forked bearers. By aggregating the settings for bearers of the same type, the processing volume can be reduced.

[0375] The SgNB change request sent from the primary base station to the secondary base station can include the radio bearer identifier. This identifier can be included in the settings for adding a bearer, modifying a bearer, or releasing a bearer. The secondary base station can uniquely identify the bearer, thereby preventing malfunctions.

[0376] The SgNB change request sent from the primary base station to the secondary base station can include identifiers indicating the maintenance / release of logical channels. It can include identifiers of maintained logical channels or identifiers of released logical channels. Flexible packet replication handover can be implemented for each logical channel.

[0377] The SgNB change request sent from the primary base station to the secondary base station can include a cause for the change. This cause can include information indicating packet replication. This information could indicate the start of packet replication settings, a change in packet replication settings, or the release of packet replication. This information can be added to the cause list shown in Section 9.2.6 of Non-Patent Document 23 (3GPP TS 36.423v14.3.0). The target for adding this information could be, for example, the Radio Network Layer in the cause list, or other components. This allows the secondary base station to smoothly implement the processing accompanying packet replication.

[0378] The aforementioned SgNB change request response sent from the secondary base station to the secondary base station may include a bearer identifier. This bearer identifier may be a bearer related to the handover of packet replication.

[0379] Similar to the SgNB change request mentioned above, the secondary base station can include the bearer identifier in the settings for adding, modifying, and releasing bearers. These settings can be, for example, equivalent to the settings in the E-RABs Admitted To Be Added Item, E-RABs Admitted To Be Modified Item, and E-RABs Admitted To Be Released Item sections of section 9.1.3.6 of Non-Patent Document 23 (3GPP TS36.423 v14.3.0) for the SCG bearer and split bearer. This enables bearer identification during packet duplication handover.

[0380] Alternatively, the secondary base station can include the identifiers of the aforementioned bearers in a list of disallowed bearers. This list of disallowed bearers can, for example, be equivalent to the E-RABsNot Admitted List in section 9.1.3.6 of Non-Patent Document 23 (3GPP TS36.423 v14.3.0). As an alternative to the E-RABs Not Admitted List, a list of disallowed PDU sessions or a list of disallowed radio bearers can be used. The primary base station can implement control over disallowed bearers.

[0381] In the above description, as an alternative to the E-RABs Admitted To Be Added Item, settings related to the added PDU session or settings related to the added radio bearer can be used. New settings related to the added PDU session and / or settings related to the added radio bearer can be added. The same applies to the E-RABs Admitted To Be Modified Item and the E-RABs Admitted To Be Released Item. When the primary base station is a MgNB, the method shown in Embodiment 2 can be applied. Furthermore, flexible settings can be made for each PDU session and each radio bearer.

[0382] In the above content, the settings in the fork bearer can be settings in the MCG fork bearer, settings in the SCG fork bearer, or settings in both. The settings in the fork bearer can include information indicating the type of fork bearer. The type of fork bearer can be an MCG fork bearer, an SCG fork bearer, or an SCG-only fork bearer. This avoids the complexity of design in the inter-base station interface.

[0383] Alternatively, the settings in the forked bearers mentioned above can be divided into (a) settings in the MCG forked bearers, (b) settings in the SCG forked bearers, and (c) settings in the SCG-only forked bearers. By aggregating the settings for bearers of the same type, the processing volume can be reduced.

[0384] The secondary base station can include information related to packet replication in the SgNB change request affirmative response. In the above, information related to packet replication can be included in the same location as the aforementioned bearer identifier, indicating UE-specific settings, such as those included in SCG-Config.

[0385] The information related to grouped replication mentioned above can be information indicating whether grouped replication has occurred, information indicating the type of grouped replication, or information obtained by combining both. For example, information indicating that no grouped replication occurs can be included in information indicating the type of grouped replication.

[0386] Alternatively, the information related to packet replication mentioned above may include information about the logical channel, information about the RLC settings, or information about the radio carrier. Multiple types of the above information may also be combined.

[0387] The aforementioned information related to packet replication can be included within the information related to radio bearers. For example, in Non-Patent Document 24 (3GPP TS36.331 v14.3.0), the bearer addition and change list, such as the section equivalent to DRB-ToAddModListSCG-r12, can include information related to packet replication. For example, the logical channel identifier and RLC setting information can be combined and included in this section in the form of packetdupListSCG. The radio carrier information can be included in the above combination. Packet replication using CA can be implemented.

[0388] The above-mentioned combination included in packetdupListSCG can be one. This combination can include the logical channel identifier and RLC configuration information. This combination can be the secondary base station side configuration in packet replication using DC. Alternatively, the combination included in packetdupListSCG can be two. This combination can include the logical channel identifier, RLC configuration, and radio carrier information. This combination can be used for packet replication using CA in the SCG bearer.

[0389] Alternatively, information related to packet replication can be included in the bearer release overview in Non-Patent Document 24 (3GPP TS36.331 v14.3.0), for example, in a section equivalent to DRB-ToReleaseModListSCG-r12. For example, it is possible to switch from packet replication using DC to packet replication using CA in the MCG bearer.

[0390] Alternatively, information related to the combination of logical channels and radio carriers can be included in the MAC configuration settings, for example, in a section equivalent to MAC-MainConfig in Non-Patent Document 24 (3GPP TS36.331 v14.3.0). This can reduce the amount of processing in the MAC layer.

[0391] The information related to packet replication mentioned above can be packet replication information from the SRB. For example, packet replication information from the SRB can be included in the SCG-Config mentioned above. This can improve the reliability of C-Plane communication.

[0392] The information contained in the notification sent by the secondary base station to the primary base station regarding the existence of an SgNB change request can be the same as the information contained in the affirmative response to the SgNB change request. This avoids the design complexities associated with handover involving packet replication.

[0393] The information included in the SgNB reconfiguration completion message sent from the primary base station to the secondary base station can be the same as the information included in the SgNB change request affirmative response. The SCG-Config in the SgNB change request affirmative response can be interpreted as SCG-ConfigInfo. This avoids the design complexities related to packet replication handover.

[0394] The information contained in the SgNB change confirmation notification sent from the primary base station to the secondary base station can be the same as the information contained in the SgNB reconfiguration completion notification. This avoids the design complexities associated with packet replication handover.

[0395] The aforementioned RRC connection reconfiguration sent from the primary base station to the UE may include information related to packet replication. This packet replication-related information may be the same as the information included in the aforementioned SgNB change request affirmative response. The primary base station may add RRC settings related to communication with the primary base station to the aforementioned packet replication-related information. These RRC settings related to communication with the primary base station may be settings related to packet replication using the primary base station.

[0396] The primary base station can contain information related to packet replication, such as the packetdupListSCG mentioned above. Two combinations can be included in the packetdupListSCG. This combination can include the logical channel identifier and RLC configuration information. It can also include radio carrier information. By including radio carrier information, packet replication using CA can be implemented. Both pieces of information included in this combination can be settings used in communication between the UE and the primary base station. Packet replication using CA in the MCG bearer can be implemented. One piece of information is a setting used in communication between the UE and the primary base station, and the other is a setting used in communication between the UE and the secondary base station. Packet replication using DC can be implemented. Alternatively, both pieces of information can be settings used in communication between the UE and the secondary base station. Packet communication using CA in the SCG bearer can be implemented.

[0397] The packet replication switching method shown in Embodiment 2 can be applied to both packet replication settings and packet replication releases. By making the signaling related to packet replication common, design complexity can be avoided.

[0398] The packet replication switching method shown in Embodiment 2 can be applied to multiple connections. This can improve the reliability of packet transmission and reception in multiple connections.

[0399] In packet replication within a multi-connectivity environment, a forked bearer via two base stations can be used. In the aforementioned RRC connection reconfiguration notification to the UE from the primary base station, information related to packet replication may be included. This information may include information identifying the SCG. This information can be a newly created SCG identifier or the identifier of the secondary base station. The UE can identify the SCG based on the identifier of the cell belonging to that SCG. This cell identifier could be, for example, the identifier of a PSCell or the identifier of an SCell within the SCG.

[0400] In packet replication within a multi-connectivity environment, forked bearers via three or more base stations can be used. The RRC connection reconfiguration notification from the primary base station to the UE may include information related to packet replication. This information may include the aforementioned SCG identification information. The packet replication-related information may include three or more combinations of logical channel identifiers and RLC configuration information. For example, three or more combinations included in packetdupListSCG may be used. Each combination can be used as the logical channel and RLC configuration for use in each base station.

[0401] In packet replication within a multi-connectivity environment, the UE can start / stop packet replication using MAC signaling from any base station. This MAC signaling can contain information about the logical channel being started / stopped. Information about the base station using the logical channel can also be utilized. Base station information can be its identifier, such as gNB-ID, the identifier of the PCell or PSCell, or the MCG-ID or SCG-ID. New MCG-IDs and / or SCG-IDs can be created. Starting / controlling packet replication within the UE becomes easier.

[0402] Alternatively, in the aforementioned MAC signaling, the base station using each logical channel can individually notify the UE of the start / stop of that logical channel. This can reduce the amount of MAC signaling.

[0403] In this second embodiment, logical channel information may not be included. For example, logical channel information may not be included in settings that use DC packet replication or during switching to settings that use DC packet replication. This reduces the signaling size.

[0404] In this second embodiment, the UE can receive signals from all base stations constituting the DC / MC. These signals can be, for example, MAC signaling. Control of packet copying becomes easier.

[0405] In the above description, the UE can receive signals from all carriers used by the UE in each base station. These signals can be, for example, MAC signaling. This improves the scheduling flexibility within the base station. Alternatively, the UE can also receive signals, such as MAC signaling, from a subset of the carriers used by the UE in each base station. This subset of carriers can be, for example, PCell or PSCell. The base station and the UE can use PCell and / or PSCell to transmit and receive this MAC signaling. This reduces the UE's power consumption.

[0406] Alternatively, in this embodiment 2, the UE can be configured to receive signals from the base station that sent the packet during the packet copying operation, such as MAC signaling. This can reduce the power consumption of the UE.

[0407] In the above scenario, the UE can receive signals, such as MAC signaling, from all carriers used by the UE in each base station. This improves the scheduling flexibility within the base station. Alternatively, the UE can also receive signals, such as MAC signaling, from a subset of the carriers used by the UE in each base station. This subset of carriers could be, for example, PCell or PSCell. The base station and UE can use PCell and / or PSCell to transmit and receive this MAC signaling, further reducing the UE's power consumption.

[0408] Alternatively, in this second embodiment, the UE can be configured to receive signals from the main base station, such as MAC signaling. This reduces the UE's power consumption and simplifies control within the main base station.

[0409] In the above scenario, the UE can receive signals from all carriers used by the UE in the primary base station, such as MAC signaling. This improves the scheduling flexibility within the primary base station. Alternatively, the UE can also receive signals from a subset of the carriers used by the UE in the primary base station, such as MAC signaling. This subset of carriers could be, for example, PCell 1. The base station and the UE can use PCell 1 to transmit and receive this MAC signaling, further reducing the UE's power consumption.

[0410] According to this embodiment 2, packet replication using CA and packet replication using DC can be switched between each other, ensuring communication reliability, for example, when the UE is moving. Furthermore, throughput can be improved.

[0411] Implementation Method 3.

[0412] When packet replication stops, it is recommended to clear the data at the RLC layer (see Non-Patent Document 20 (R2-1704836)). Furthermore, in downlink packet replication, it is recommended not to perform start / stop control from the base station to the UE (see Non-Patent Document 21 (R2-1702753)).

[0413] Furthermore, in RLC-AM, the RLC entities on the transmitting and receiving sides are integrated (see Non-Patent Document 17 (TS36.322 v14.0.0)).

[0414] However, in packet replication using RLC-AM, such as packet replication in SRB, the following problem arises because uplink packet replication stops: the RLC layer cache in downlink packet replication is also eliminated.

[0415] In this third embodiment, a method for solving the above-mentioned problems is disclosed.

[0416] The UE clears only the transmit-side buffer of the RLC-AM. The base station clears only the transmit-side buffer of the RLC-AM. The clearing of the aforementioned buffers in the UE and / or base station can be performed when uplink packet replication stops.

[0417] The UE can clear the variables and transmission window on the transmitting side of RLC-AM.

[0418] As another method, the base station can simultaneously control both the downlink and uplink of packet replication. This simultaneous control is possible when using packet replication with RLC-UM and / or RLC-TM.

[0419] The method shown in Implementation 3 prevents the cache from being cleared during downlink packet replication due to the cessation of uplink packet replication, thus ensuring data continuity.

[0420] Implementation Method 4.

[0421] In NR, the RRC_INACTIVE state has been newly introduced as a UE state (see Non-Patent Document 9 (3GPP TR38.804 V14.0.0)). Furthermore, NR promotes support for small data transmission from UEs in the RRC_INACTIVE state (see Non-Patent Document 9 (3GPP TR38.804 V14.0.0)).

[0422] However, the support for packet replication as described in Implementation 1 and Implementation 2 was not discussed regarding small data transmission from UEs in the RRC_INACTIVE state. Therefore, when a UE using packet replication for transmission transitions to the RRC_INACTIVE state, the method for small data transmission is unclear, leading to a problem where data cannot be transmitted to the base station.

[0423] In this fourth embodiment, a method for solving the above-mentioned problems is disclosed.

[0424] The UE does not support packet replication in the RRC_INACTIVE state.

[0425] The UE can retain settings related to packet replication. These settings are retained when the UE transitions to the RRC_INACTIVE state. These settings can be related to packet replication using DC or packet replication using CA. Packet replication can be quickly restarted when the UE transitions back to the RRC_CONNECTED state.

[0426] The UE can stop packet copying. The UE can stop packet copying when it transitions to the RRC_INACTIVE state. The UE can stop packet copying voluntarily, or the base station or primary base station can instruct the UE to stop packet copying. This instruction can use the MAC signaling for stopping packet copying described in Implementation 1. Alternatively, this instruction can be included in the RRC_INACTIVE state transition instruction from the base station or primary base station to the UE.

[0427] The UE can release settings related to packet replication. This can be done when the UE transitions to the RRC_INACTIVE state. The UE can release the settings autonomously, or the base station or primary base station can instruct the UE to release the settings. The UE can release packet replication settings together with the release of DC or CA settings. This can reduce the storage usage of the UE in the RRC_INACTIVE state.

[0428] As another example, the base station or primary base station can notify the UE of the maintenance / release of packet replication settings. The base station or primary base station can include this maintenance / release notification in the RRC_INACTIVE transfer instruction to the UE. For example, this instruction can include an identifier indicating whether to maintain or release the packet replication settings. Thus, the base station or primary base station can, for example, perform flexible settings corresponding to the radio channel conditions.

[0429] The base station or main base station can set the maintenance / release settings for packet replication on a per-bearer basis. Packet replication can be flexibly applied on a per-bearer basis.

[0430] Regarding the above-mentioned method for maintaining / releasing the setting of packet replication of each bearer from the base station or the main base station to the UE, the following four examples (1) to (4) are disclosed.

[0431] (1) Decisions are made using standards.

[0432] (2) Common communication order.

[0433] (3) Dedicated signaling.

[0434] (4) Combinations of (1) to (3) above.

[0435] In (1) above, for example, the maintain / release setting can be determined for each bearer type. For example, it can be set to maintain packet replication for SRB and release packet replication for DRB. Or, for example, it can be set to maintain packet replication for SRB0, release for SRB1, maintain for SRB2, release for SRB3, and release for DRB. This can reduce signaling load.

[0436] In (2) above, the base station or master base station can use system information to notify maintain / release. This can reduce signaling load.

[0437] In (3) above, the base station or primary base station may, for example, use RRC-specific signaling to notify the maintenance / release. This RRC-specific signaling may be an RRC_INACTIV transfer indication to the UE, or other RRC-specific signaling. This RRC-specific signaling may contain the identifier of the bearer configured to maintain packet replication, the identifier of the bearer configured to release packet replication, or identifiers of both parties. The maintenance / release of packet replication can be flexibly configured on a per-bearer basis.

[0438] In (3) above, the maintenance / release settings for group replication can be configured for each bearer type. The maintenance / release settings for group replication for each bearer type can be set to be the same as those shown in (1) above. Flexible configuration is possible for each bearer type.

[0439] In (4) above, for example, the maintenance / release of packet replication settings in each SRB can be determined using standards. The maintenance / release of packet replication settings in each DRB can be notified to the UE individually by the base station or the primary base station. This can reduce signaling volume and improve the flexibility of each DRB's settings.

[0440] The UE can use packet replication for small data transmissions. These small data transmissions can be performed after transitioning to the RRC_CONNECTED state. The UE can retain the packet replication settings. This retention of settings can be performed when the UE transitions to the RRC_INACTIVE state. Control of the UE related to data transmission becomes easier.

[0441] The UE can initiate packet copying. This packet copying initiation can occur after the UE transitions to the RRC_CONNECTED state. The UE can initiate the packet copying initiation autonomously. For example, it can be done using the information maintaining the packet copying initiation / stopping status described in Embodiment 1. Alternatively, it can be done using a packet copying initiation indication from the base station or primary base station. This packet copying initiation indication can be included in the RRC_CONNECTED transition indication from the base station or primary base station to the UE, or it can be notified separately from the RRC_CONNECTED transition indication. The packet copying initiation indication can also be notified to the UE from the base station or primary base station using MAC signaling as described in Embodiment 1.

[0442] The UE can release settings related to packet replication during cell reselection. Alternatively, the UE can release settings related to packet replication when transitioning to the RRC_IDLE state. The UE can release these settings autonomously or using instructions from the base station or the primary base station. This can reduce the UE's storage usage during cell reselection and / or in the RRC_IDLE state.

[0443] According to this embodiment 4, erroneous operations of the UE related to small data transmission during INACTIVE can be prevented.

[0444] Implementation Method 5.

[0445] In the data transmission to the secondary base station in the RCC_INACTIVE state described in Embodiment 4, it is recommended to perform SCG addition after recovery from the RCC_INACTIVE state and then transmit the data to the secondary base station (see Non-Patent Document 25 (R2-1704425)). As another method, it is recommended to perform early SCG bearer configuration along with the SCG addition upon recovery from the RCC_INACTIVE state (see Non-Patent Document 26 (R2-1704420)).

[0446] However, in the two methods mentioned above, the UE waits for the SCG to be added before sending the data to the secondary base station, which causes the following problem: there is a delay from the start of data transmission from the UE to the secondary base station.

[0447] In this fifth embodiment, a method for solving the above-mentioned problems is disclosed.

[0448] The UE transmits data to the secondary base station via the primary base station. This data can be transmitted using an SCG forked bearer. The primary base station then transmits this data to the secondary base station. This transmission can utilize an inter-base station interface, such as the X2 interface.

[0449] In this implementation method 5, the primary base station can switch the SCG bearer to an SCG fork bearer. The primary base station can notify the secondary base station of the switch request. The secondary base station can notify the primary base station of its response to the request. The primary base station can perform the switch simultaneously with the RRC_INACTIVE state transition indication to the UE, or it can perform it separately from the state transition indication. The primary base station can include the switch indication in the RRC_INACTIVE state transition indication to the UE. The switch indication can include the identifier of the SCG bearer. Thus, for the SCG bearer, rapid data transmission from the UE to the secondary base station can also be achieved.

[0450] Figure 15 This is a flowchart illustrating the small data transmission from a UE in the RRC_INACTIVE state to a secondary base station. Figure 15 The example shown illustrates a primary base station (eNB) and a secondary base station (gNB). The primary base station can also be a gNB. Furthermore, the secondary base station can also be an eNB. Figure 15 An example is shown where the UE transitions to the RRC_CONNECTED state after a small data transmission, but the UE can also remain in the RRC_INACTIVE state.

[0451] exist Figure 15 In step ST3001, the UE in the RRC_INACTIVE state begins random access processing with the primary base station. In step ST3001, the UE sends a random access preamble (RApreamble) to the primary base station. In step ST3002, the primary base station sends a random access response (RAResponse) to the UE. This response contains uplink permission for the UE.

[0452] exist Figure 15 In step ST3003 shown, the UE sends an RRC connection recovery request (RRCConnectionResumeRequest) to the primary base station.

[0453] exist Figure 15 In step ST3005, the UE sends uplink data to the primary base station for the secondary base station. In step ST3006, the primary base station sends the uplink data to the secondary base station.

[0454] exist Figure 15In step ST3007, the primary base station notifies the UE that the RRC connection has been restored (RRCConnectionResume). In step ST3008, the UE notifies the primary base station that the RRC connection restoration is complete (RRCConnectionResumeComplete). In step ST3008, the UE transitions to the RRC_CONNECTED state.

[0455] By employing the method disclosed in this embodiment, the UE can quickly perform data transmission to the secondary base station in the INACTIVE state.

[0456] Implementation Method 6.

[0457] In 3GPP, MC (Medium Cell Group) was proposed as a 5G technology (see Non-Patent Document 27 (R2-167583)). As MC, the scenario of configuring a UE to connect one primary base station to multiple secondary base stations was explored. Furthermore, as MC, support for MCG fork bearers and SCG bearers was proposed. Additionally, a group consisting of MeNB cells is called an MCG, and a group consisting of SgNB cells is called an SCG.

[0458] However, for MCs with two or more secondary base stations, the architecture including the upper-level NW device (hereinafter also referred to as the upper-level NW) and the setting method of the MC, such as how to set up multiple secondary base stations, are not disclosed. In this embodiment 6, the architecture including the upper-level NW and the setting method of the MC are disclosed.

[0459] Figure 16 This diagram illustrates the architecture of the MC (Medium-terminal NB). It shows the following configuration: the upper-level NW (Network Wireless Terminal) is the EPC (Engineering Processing Unit), the primary base station is the base station in LTE (eNB), and the secondary base station is the base station in NR (gNB). The primary base station in LTE is referred to as the MeNB, and the secondary base station in NR is referred to as the SgNB. The eNB's protocol structure consists of PDCP, RLC, MAC, and PHY. The gNB's protocol structure consists of a new AS sublayer, PDCP, RLC, MAC, and PHY. A new AS sublayer is located above PDCP.

[0460] Figure 16 This diagram illustrates the architecture on the base station side, but the architecture on the UE side is the same except for the upper-level NW. In one UE, a PDCP is constructed, which constitutes the RLC, MAC, and PHY used by the MeNB, and also constitutes the RLC, MAC, and PHY used by each SgNB configured as the MC.

[0461] Figure 16This illustrates a scenario using MCG forked bearer. The upper-level NW is connected to the MeNB, and the SgNB used by the MC is connected to the MeNB. Downlink data is processed by the MeNB's PDCP. Even if there are multiple SgNBs, each data item is assigned a consecutive sequence number (SN) in the PDCP. The data with assigned SNs is forked between the MeNB and each SgNB. The forked data is sent to the RLC of the MeNB and each SgNB, where it is processed by the RLC, MAC, and PHY of the MeNB and each SgNB before being transmitted to the UE.

[0462] Data received by the UE from the MeNB and each SgNB is processed by the PHY, MAC, and RLC of the MeNB and each SgNB, and then transmitted to the PDCP. In the PDCP, the data is reordered based on the SN assigned to the data transmitted from the MeNB and each SgNB, and then transmitted to the upper layer.

[0463] For uplink data, the UE utilizes PDCP to process data from the upper layer. Similar to the downlink, even if there are multiple SgNBs, each data item is assigned a consecutive sequence number (SN) in PDCP. Data with assigned SNs is then branched into RLCs used by the MeNB and each SgNB for transmission. The transmitted data is processed by the RLC, MAC, and PHY of the MeNB and each SgNB, and then sent to the MeNB and each SgNB.

[0464] Data received from the UE by the MeNB and each SgNB is processed by the PHY, MAC, and RLC of the MeNB and each SgNB, and then transmitted to the MeNB's PDCP. In the MeNB's PDCP, the data is reordered based on the SN assigned to it and then transmitted to the higher-level NW.

[0465] This document discloses a method for configuring multiple SCGs as MC (Multi-Channel Groups). The MeNB configures the MC-specific SCG for the UE. The radio bearer for MC is configured within the SCG settings. This notification can utilize RRC signaling.

[0466] SCGs are configured one by one. Multiple SCGs used by the MC are configured using the configuration of one SCG. Only one SCG needs to be configured based on the number of SCGs used by the MC. Signaling for SCG configuration is performed based on the number of SCGs configured for the UE from the MeNB. In the case of the DC, only one SCG is connected; therefore, if another SCG is connected while one SCG is configured, the previously configured SCG needs to be released. In contrast, adding an SCG does not require releasing the previously configured SCG. Thus, the MeNB can configure multiple SCGs for the UE.

[0467] Information indicating an additional SCG setting can be configured to maintain the previous SCG setting. The MeNB notifies the UE of this information. This information can be included in the SCG setting itself. Alternatively, signaling for adding an additional SCG setting can be configured to maintain the previous SCG setting. By configuring this signaling separately, the UE can identify whether it is an additional SCG setting that maintains the previous SCG setting when the MeNB has an SCG setting in the signaling.

[0468] As RRC signaling, for example, RRCConnectionReconfiguration can be used for configuring RRC connections. For instance, the structure of the SCG and the structure of the bearer for MC can be included in the SCG-ConfigPartSCG within this signaling. The bearer structure includes a bearer identifier, bearer AS settings, etc.

[0469] In the case of DC, only one MCG and one SCG are set for a single bearer. If multiple SCGs are set in the MC, multiple SCGs can be set for a single bearer. In the setting of subsequent SCG structures, bearers set together with the previous SCG structures can be used. The same bearer identifier can be set. Therefore, the UE can recognize that multiple SCG structures have been set for that bearer.

[0470] The bearer settings can be different in each SCG used in the MC. In the setting of the SCG structure after the second time, if a bearer identifier is set along with the previous SCG structure, one or more parameters of the bearer AS setting for the previously set bearer identifier can be omitted. If the parameters are omitted, they can be set to the parameters of the bearer AS setting for the same bearer identifier.

[0471] An SCG identifier can be set. An SCG identifier can be included as information about the SCG structure set by the SCG. An SCG identifier can be used to set the same AS parameters for the bearer. For example, the SCG identifier can be included in the bearer structure. Thus, the UE can recognize that the bearer structure set for the SCG is the same as the bearer structure set for the SCG indicated by the SCG identifier. Therefore, the AS parameters for the bearer set for the SCG can be set to be the same as the AS parameters for the bearer set for any SCG.

[0472] Therefore, when the AS parameters for the bearer are the same for each SCG in the MC, this parameter can be omitted, or it can be set with less information. This reduces the radio resources required for the MeNB to notify the UE.

[0473] Setting the SCG identifier is disclosed, but setting the SgNB identifier is also possible. An identifier representing a group of SCGs or SgNBs can also be set. By setting such an identifier, when MCs are set in multiple SgNBs, the UE can identify the setting for each SgNB or each SgNB group, rather than the setting for each cell. This is effective, for example, when changing settings on a per-SgNB or per-SgNB group basis. The capability map reduces the information notified to the UE from the MeNB.

[0474] Figure 17 and Figure 18 This is a diagram illustrating an example of the process of setting up an MC. Figure 17 and Figure 18 Connect at the location of boundary line BL1718. Figure 17 and Figure 18 The example shown uses MeNB and two SgNBs (SgNB1, SgNB2). Figure 17 and Figure 18 The case using MCG fork bearer is illustrated. In step ST4201, data communication occurs between the UE and the MeNB. In step ST4202, the MeNB determines whether to perform DC setting on the UE. The DC setting process can be performed using the method disclosed in Non-Patent Document 1 (TS36.300). Steps ST4203 to ST4213 illustrate the DC setting process.

[0475] In step ST4210, the MeNB routes data between itself and SgNB1, which has been configured with DC. Here, only one secondary base station is connected; therefore, similar to the existing DC, data from the upper-level NW is processed by the MeNB's PDCP and then split between the MeNB and SgNB1 for transmission. Furthermore, data received from the UE by the MeNB and SgNB1 is transmitted to the MeNB, processed by the MeNB's PDCP, and then transmitted to the upper-level NW.

[0476] The same applies to the UE side.

[0477] In step ST4214, the MeNB determines the MC (Capacity Management) setting for the UE. The MeNB decides to connect SgNB2 to the UE while maintaining the connection of SgNB1. In step ST4215, the MeNB notifies SgNB2 of the additional request from the SgNB. This signaling can apply step ST4203 in the DC (Capacity Management) setting process. The MeNB can set the bearer setting of the additional requesting SgNB2 to be the same as the bearer setting of its own eNB (MeNB). Alternatively, the MeNB can consider the bearer setting of its own eNB (MeNB) and the bearer setting of SgNB1 to determine the bearer setting of SgNB2. The bearer for which MC is performed can be set to satisfy the QoS set by the upper-level NW (Network Controller).

[0478] SgNB2 determines the AS configuration based on the bearer configuration shown in the SgNB add request from the MeNB. In step ST4216, SgNB2 notifies the MeNB of the determined AS configuration. In step ST4217, the MeNB notifies the UE of the MC configuration. The MC configuration can include the structure of the SCG of the added SgNB2 and the bearer configuration for the MC. As signaling, RRCConnectionReconfiguration can be used for RRC connection configuration.

[0479] Furthermore, in step ST4217, the MeNB can notify the UE of information regarding the additional SCG settings while maintaining the previously set SCG settings of SgNB1. By explicitly indicating this information, the UE can clearly identify whether the connection to SgNB2 is maintained while still connected to SgNB1, thus reducing the occurrence of erroneous operations.

[0480] In step ST4217, the UE, having received the SCG additional settings from SgNB2, performs MC settings for SgNB2 based on the settings from MeNB and SgNB1. In step ST4218, the UE notifies the MeNB that the RRC connection reconfiguration is complete (RRCConnectionReconfigurationComplete), which includes the completion of the MC settings.

[0481] In step ST4219, the MeNB, having identified that the UE has completed the MC configuration, notifies SgNB2 of the completion of the additional SCG configuration for SgNB2. SgNB2 recognizes that the connection configuration for the MC between it and the UE is complete.

[0482] In step ST4220, the UE initiates RA processing with SgNB2. The settings used for RA processing of SgNB2 are notified in the AS settings from SgNB2 via steps ST4216 and ST4217. After achieving synchronization through RA processing, the UE begins data communication with SgNB2 in step ST4221.

[0483] Routing functionality can be configured on a MeNB for multiple SgNBs. If only one SgNB is connected to the DC, data branching off at the SgNB side will simply be transmitted to that single SgNB. However, since the MC connects to multiple SgNBs, the MeNB needs to determine which SgNB the data branching off at the SgNB side should be sent to. Therefore, routing functionality can be configured on the MeNB to determine the destination SgNB for data transmission and to send the data to that SgNB.

[0484] In addition, the routing function can have the ability to transmit data received by the UE from this MeNB and data received by multiple SgNBs and transmitted to the MeNB via PDCP to the MeNB.

[0485] Routing functionality can be configured within the MeNB's PDCP. Routing functionality can be placed at the lowest level of the PDCP functionality. Alternatively, routing functionality can be configured separately from PDCP. While the configuration of routing functionality separately from forking functionality is disclosed, it is also possible to include routing functionality as part of forking functionality as another method. Alternatively, it can be configured as a forking functionality between the MeNB and multiple SgNBs, rather than a routing functionality performed after forking.

[0486] Routing can be performed on a per-data-data basis. Routing is done to each SgNB individually. Alternatively, the same data can be routed to the same SgNB within a specified period. This allows for flexible routing and enables routing tailored to the communication quality conditions of each SgNB.

[0487] The same applies to the UE side.

[0488] In step ST4222, the MeNB routes data between itself and SgNB1 and SgNB2, which have been configured with MC. Since there are two connected secondary base stations, data from the upper-level NW is processed by the MeNB's PDCP and then branched to the MeNB and SgNB sides for transmission. Data branched to the SgNB side is then routed to SgNB1 and SgNB2 via routing functionality and transmitted.

[0489] In addition, data received from the UE by SgNB1 and SgNB2 is transmitted to the MeNB, and together with data received by this MeNB, is transmitted to the MeNB's PDCP via routing. The data transmitted to the PDCP is processed by the PDCP and then transmitted to the higher-level NW.

[0490] Therefore, MC (Multi-Segment NodeB) can be performed using multiple SgNBs. The MeNB can configure the UE to use multiple SgNBs for MC. The UE can connect to the MeNB and the configured multiple SgNBs to perform MC.

[0491] When the SgNB is deactivated, the SCG structure of each SgNB with MC set can be deactivated one by one.

[0492] Therefore, by individually configuring or decommissioning auxiliary base stations for MC (Multi-Channel Network), the appropriate SgNB can be configured for the UE based on the radio wave transmission status of the MeNB and each SgNB. This allows for higher throughput for the UE.

[0493] Furthermore, by configuring or decommissioning auxiliary base stations for MC one by one, even if the additional configuration of the MC-using SgNB fails midway, the previously successful MC-using SgNB configuration can be maintained, and the MC can be performed using that SgNB configuration. The next SgNB can be added and configured again from the successful MC-using SgNB configuration. Even when the additional configuration of SgNBs fails, a robust and stable system can be constructed.

[0494] Other methods for configuring multiple SCGs as MCs are disclosed. The MeNB configures the MC-specific SCG for the UE. The radio bearer for MC is configured in the SCG settings. This notification can use RRC signaling.

[0495] Multiple SCGs can be configured. Multiple SCGs for MC (MC Controller) can be configured in a single configuration. The MeNB sends signaling to the UE for multiple SCG configurations. As an MC, signaling for multiple SCG configurations can be set. Therefore, the MeNB can configure multiple SCGs for the UE.

[0496] If a DC has been previously set up, multiple SCGs used for MC can be set up in a single setup after the previous DC settings are released. Furthermore, if an MC has been previously set up and then different SgNB SCGs are used for MC, the MC settings can be re-set in a single setup after the previous MC settings are released.

[0497] The previous DC or MC settings can be released separately from the signaling used for setting multiple SCGs for MC. Alternatively, the previous DC or MC settings can be released using the same signaling as the signaling used for setting multiple SCGs for MC. This reduces signaling volume and control latency.

[0498] As RRC signaling, for example, RRCConnectionReconfiguration can be used for configuring RRC connections. This signaling can, for example, contain information about multiple SCGs being configured. The information for multiple SCGs can be a list. For example, a list of multiple SCGs can be set, containing structure information for each SCG corresponding to the number of SCGs configured. The structure information for each SCG can, for example, be set in the SCG-ConfigPartSCG mentioned above.

[0499] You can set identifiers for multiple configured SCGs. You can also set identifiers for multiple configured SgNBs. For example, when deconfiguring multiple SCGs used for MC at the same time, you can reduce the amount of information used for configuration by including the identifiers of the SCG groups assigned during configuration in the signaling used to deconfigure the SCGs.

[0500] The UE can associate the identifiers of multiple SCG groups with the SCGs of the SgNB contained in the SCG group for storage. The UE can discard this storage if the connection to the base station is in an Idle state. The UE can maintain this storage if the connection to the MeNB is in a connected and inactive state, or if the connection to the MeNB is in a connected or inactive state.

[0501] For example, when multiple SCGs are added to the MC after the MC configuration has been deactivated, the identifiers of the previously configured SCG groups are included in the signaling used for the addition configuration. The UE can identify the SCG structure of the SgNB included in the SCG group from the identifiers of the multiple SCG groups previously notified by the MeNB. This reduces the amount of information required for the addition configuration.

[0502] The information for each SCG configured as a multiple SCG for MC can include the SCG structure and the structure for carrying out the MC. The structure for carrying includes a bearer identifier and an AS setting for the bearer. Regarding the bearer, the same setting method as described above can be used. Furthermore, as mentioned above, SCG identifier information can be included in each SCG. Therefore, the MeNB can configure the SCG structure of multiple SgNBs for MC for the UE at once.

[0503] Figure 19 and Figure 20 This is a diagram illustrating an example of the process of setting up an MC. Figure 19 and Figure 20 Connect at the boundary line BL1920. Figure 19 and Figure 20 The example shown uses MeNB and two SgNBs (SgNB1, SgNB2). Figure 19 and Figure 20 This illustrates a scenario where MCG fork bearers are used. Figure 19 and Figure 20 This demonstrates a method for setting up multiple SgNBs for a single MC. Figure 19 and Figure 20 The process shown includes and Figure 17 and Figure 18 The process shown has the same steps, therefore, the same step numbers are added to the same steps, and common descriptions are omitted.

[0504] In step ST4301, the MeNB determines to the UE that multiple SgNB MCs are used. Here, the MeNB determines that SgNB1 and SgNB2 are used for MC. In steps ST4203 and ST4215, the MeNB notifies SgNB1 and SgNB2 of the additional request from the SgNB. In steps ST4204 and ST4216, SgNB1 and SgNB2 notify the MeNB of the AS settings determined by the additional request.

[0505] In step ST4302, the MeNB notifies the UE of the MC settings. The MC settings can include the structure of the SCGs of multiple SgNBs used to notify the MC, as well as the structure for MC bearer configuration. As signaling, RRCConnectionReconfiguration can be used for RRC connection configuration.

[0506] Furthermore, in step ST4302, the MeNB can notify the UE of the release of a previously configured DC or MC. By issuing this notification, SCG configurations for multiple SgNBs used for MC can be performed simultaneously. The UE can clearly identify the configurations connected to SgNB1 and SgNB2 for MC purposes, reducing the occurrence of erroneous operations.

[0507] In step ST4302, the UE that receives the SCG additional settings from SgNB1 and SgNB2 performs MC settings for MeNB, SgNB1, and SgNB2 according to these settings. In step ST4303, the UE notifies the MeNB that the RRC connection reconfiguration is complete, including the completion of MC settings.

[0508] In step ST4207, the MeNB that has identified that the UE has completed the MC configuration sends a signaling message to SgNB1 indicating that the additional configuration of the SCG for each SgNB has been completed, and in step ST4219, it sends a signaling message to SgNB2 indicating that the additional configuration of the SCG for each SgNB has been completed. SgNB1 and SgNB2 recognize that the connection configuration for the MC between them and the UE has been completed.

[0509] In steps ST4208 and ST4220, the UE initiates RA processing for SgNB1 and SgNB2. The settings for RA processing of SgNB1 are notified in the AS settings from SgNB1 via steps ST4204 and ST4304. The settings for RA processing of SgNB2 are notified in the AS settings from SgNB2 via steps ST4216 and ST4302. After achieving synchronization through RA processing, the UE begins data communication with SgNB1 and SgNB2 in steps ST4209 and ST4221.

[0510] Steps ST4222 to ST4226 are related to Figure 17 and Figure 18 The same process applies, so the explanation is omitted here.

[0511] Therefore, MC (Multi-Segment NodeB) can be performed using multiple SgNBs. The MeNB can configure the UE to use multiple SgNBs for MC. The UE can connect to the MeNB and the configured multiple SgNBs to perform MC.

[0512] When deactivating the SCG settings of multiple SgNBs, the SCG structures of all SgNBs with MC settings are deactivated simultaneously. This is achieved using a single signaling message from the MeNB to the UE to deactivate the SCG settings of multiple SgNBs.

[0513] Therefore, by setting or deactivating the secondary base station for MC in a single step, signaling load can be reduced. Furthermore, MC setting or deactivation control can be implemented with lower latency. Thus, the appropriate SgNB can be configured for the UE based on rapid temporal changes in the radio wave transmission status of the MeNB and each SgNB. This provides higher throughput for the UE.

[0514] As a method for setting or deactivating multiple SCGs for MC, methods for setting or deactivating SCGs one by one and methods for setting or deactivating multiple SCGs for MC in a single setting are disclosed. These methods can be appropriately combined. For example, multiple SCGs can be set instead of setting them one by one. Multiple SCGs can be set for the same bearer. As a method for setting multiple SCGs, a method for setting multiple SCGs for MC in a single setting can be used.

[0515] It can include information indicating whether additional SCG settings are being maintained while preserving previous SCG settings. The UE can identify whether multiple SCG settings for the MC made through a single setting are additional SCG settings being maintained while preserving previous SCG settings.

[0516] In this case, information for deactivating the MC (Multi-Channel Network) setting and information for deactivating one or more SCG (Signal Groups) settings can be set separately. The information for deactivating the MC setting can be information for deactivating the current bearer configuration. This information can be used, for example, to deactivate an MCG fork bearer. The information for deactivating one or more SCG settings can be information for removing the settings of that one or more SCGs from the MC, i.e., information for removing the settings of that one or more SCGs from the SCGs of the SgNB (Signal Group Network) performing the MC. The SCG can be determined using its identifier.

[0517] The MeNB can use the above information appropriately depending on the situation. The MeNB sets the above information based on whether it is to cancel the settings for the MC or to cancel the settings for one or more SCGs. The UE that receives the above information can determine whether to cancel the settings for the MC or to cancel the settings for one or more SCGs.

[0518] For example, when a notification is received that a setting for MC is being cleared while multiple SCGs are configured, the UE clears the settings of all SCGs to clear the MC setting. The bearer type with the MC setting is then cleared. For example, when a notification is received that one or more SCGs are being cleared while multiple SCGs are configured, the UE clears the settings of those SCGs. However, the MC setting is not cleared. The bearer type with the MC setting is not cleared. MC continues to be implemented using the remaining SCGs.

[0519] Therefore, the SCG used for the MC can be flexibly configured. The MC using the appropriate SgNB can be flexibly configured based on factors such as the UE's mobility speed, the services provided, the base station configuration, and changes in the radio wave transmission environment between the UE and the base station. This capability map enables increased throughput.

[0520] Other methods for configuring multiple SCGs as MCs are disclosed. The MeNB configures the radio bearer for MCs for the UE. The SCG for MC is configured in the radio bearer settings. This configuration can be notified using RRC signaling.

[0521] The MeNB configures the SCG of one or more SgNBs for the radio bearer performing MC for the UE. When there are a large number of secondary base stations that can be connected to the UE's MC, a large number of SgNBs' SCGs can be configured for one or more bearers at once, thus reducing signaling load.

[0522] As RRC signaling, for example, RRCConnectionReconfiguration can be used for configuring RRC connections. This signaling may include information about one or more radio bearers for MC configuration. The information about one or more radio bearers can be a list. For example, a list of one or more radio bearers for MC configuration can be set, and it may include the structure of the SCG for each radio bearer and the bearer structure for each SCG, corresponding to the number of radio bearers for MC configuration. The structure of the SCG and the bearer structure information for each radio bearer can be configured, for example, in the SCG-ConfigPartSCG described above.

[0523] The information for one or more wireless bearers set in the list may include the wireless bearer's identifier. In this case, the wireless bearer identifier may not be included in the aforementioned SCG-ConfigPartSCG. Alternatively, the information for one or more wireless bearers set in the list may also not include the wireless bearer's identifier. In this case, the wireless bearer identifier may be included in the aforementioned SCG-ConfigPartSCG. By setting the wireless bearer identifier in this way, it becomes easier to configure the wireless bearers for the MC.

[0524] As bearer structure information for each SCG, it may include an SCG identifier that sets the bearer structure to be the same. When the SCG identifier is included as bearer structure information notified by the MeNB, the UE can determine that the same bearer structure is applied as that for the SCG with that SCG identifier. If some bearer structures are different, only the SCG identifier and the information of the different bearer structures may be included as bearer structure information. The bearer structure information not included in the information may be the same as the bearer structure information for the SCG identifier.

[0525] Therefore, the bearer structure information for each SCG that is notified from the MeNB to the UE does not need to include all the bearer structure information, thus reducing the amount of information required for signaling.

[0526] In the example above, the SCG structure information and bearer structure information for each radio bearer performing MC configuration are set in SCG-ConfigPartSCG. Alternatively, the SCG structure information and bearer structure information can be set separately. For example, the bearer structure information in SCG-ConfigPartSCG can be set separately from SCG-ConfigPartSCG. The bearer structure information for one or more radio bearers can also be set in a list. Alternatively, the SCG structure information can be set in SCG-ConfigPartSCG.

[0527] This method can be used when the bearer settings are the same in all SgNBs of the MC. In this case, the bearer structure information for each SCG can be omitted, which can reduce the amount of information required for signaling.

[0528] The MeNB configures the radio bearer for the MC (MC) in the UE settings. During the radio bearer configuration, the above procedure can be applied to the SCG (SCG) configuration process for the MC. For example, in... Figure 19 and Figure 20 In step ST4302 of the process shown, the MeNB notifies the UE of information about one or more radio bearers for MC configuration, instead of the SCG configuration of one or more SgNBs for MC configuration.

[0529] As one or more radio bearer information, for example, a list of one or more radio bearers for MC configuration can be set, and it can include the SCG structure for each radio bearer and the bearer structure for each SCG, corresponding to the number of radio bearers for MC configuration. The SCG structure and bearer structure information for each radio bearer can be set, for example, in the SCG-ConfigPartSCG mentioned above. Here, the SCG structure and bearer structure information for SgNB1 and SgNB2 are set.

[0530] In step ST4302, the UE that receives one or more radio bearer information performs MC configuration for MeNB, SgNB1, and SgNB2 according to the settings. In step ST4303, the UE notifies the MeNB that the RRC connection reconfiguration is complete, including the completion of MC configuration.

[0531] By employing this method, a large number of SgNBs can be configured with SCGs at once for one or more bearers, thus reducing signaling load. Furthermore, since configuration can be performed all at once, MC control can be executed with low latency. Moreover, because the configuration is done for each bearer individually, when bearer types are changed or modified on a per-bearer basis, only the configuration of the target bearer needs to be changed or modified, thereby avoiding control complexity. Additionally, for example, the processing load in the UE can be reduced.

[0532] When communicating data between the MeNB and each SgNB, the data can be assigned an SgNB identifier. Furthermore, each SgNB can notify the MeNB of the downlink data transmission status from its own SgNB to the UE. For example, each SgNB can notify the MeNB of the highest PDCP PDU SN successfully transmitted to the UE from the PDCP PDUs transmitted from the MeNB. For example, each SgNB can notify the buffer size for its own SgNB for bearers with configured MCs. The buffer size can be the amount of data required to satisfy the configured QoS. Information about each bearer with configured MCs can also be notified.

[0533] For example, each SgNB can notify the buffer size of its own SgNB for UEs with MC configured. The notified buffer size can be set to the minimum required data size. For example, each SgNB can notify information about packets lost in its own SgNB from data transmitted from the MeNB. Each SgNB can assign an identifier to the downlink data transmission status from its own SgNB to the UE notified by the MeNB.

[0534] Therefore, by assigning an identifier to each SgNB, each SgNB can confirm whether there is a notification for itself. Furthermore, the MeNB can identify from which SgNB the notification was received. The MeNB can use downlink data transmission status from each SgNB to determine the MC settings, modifications, changes, and cancellations made by the SgNB. Additionally, the MeNB can use downlink data transmission status from each SgNB to determine which SgNB to route packets to. It can perform MC settings and routing corresponding to the data transmission status between each SgNB and the UE.

[0535] The method for data forking in the uplink of the MC is disclosed. The MeNB sets multiple thresholds for implementing transmission for the SgNB and notifies the UE of these multiple thresholds. Since multiple SgNBs in the MC are set for MC use, multiple thresholds are set according to the number of SgNBs set, rather than being limited to a single threshold.

[0536] For example, a threshold can be set equivalent to the number of SgNBs designated for use by the MC. Alternatively, a group consisting of one or more SgNBs can be set, and a threshold equivalent to the number of SgNBs in that group can be set. The MeNB sets these multiple thresholds and notifies the UE. This notification can be made using RRC signaling.

[0537] For example, when three SgNBs are configured for MC use, three thresholds are set and the UE is notified. The thresholds are set to TH1, TH2, and TH3. If the UE's uplink data buffer is below TH1, the UE only transmits uplink data to the MeNB. If the UE's uplink data buffer is greater than TH1 but less than TH2, the UE transmits uplink data to the MeNB and one SgNB. If the UE's uplink data buffer is greater than TH2 but less than TH3, the UE transmits uplink data to the MeNB and two SgNBs. If the UE's uplink data buffer is greater than TH3, the UE transmits uplink data to the MeNB and all three SgNBs.

[0538] Therefore, by periodically increasing or decreasing the number of SgNBs used in uplink transmission, the following situation can be prevented: the UE sends data to a large number of SgNBs even when the uplink data volume is small. This can reduce the increase in UE power consumption.

[0539] As a method for setting multiple thresholds, one threshold can be set, and the other thresholds can be set to the value obtained by multiplying the set threshold by a predetermined number. For example, only TH1 can be set, and TH2 can be set to TH1 × 2, TH3 to TH1 × 3. As other examples, TH2 can be set to TH1 × 1.5, TH3 to TH1 × 2. The predetermined number can be determined in advance by standards, etc. Alternatively, the UE can be notified quasi-statically using RRC signaling. This reduces the amount of signaling sent to the UE.

[0540] The MeNB can configure the UE to send uplink data to which SgNB when a threshold is exceeded. For example, it can set a priority order for SgNB usage. The MeNB notifies the UE of this priority order. For instance, if three SgNBs are designated as MCs, their priority order can be set from high to low as SgNB1, SgNB2, and SgNB3. The MeNB can associate the identifiers of each SgNB with the priority order and notify the UE accordingly.

[0541] If the UE's uplink data buffer size is below TH1, the UE only transmits uplink data to the MeNB. If the UE's uplink data buffer size is greater than TH1 but less than TH2, the UE transmits uplink data to both the MeNB and SgNB1. If the UE's uplink data buffer size is greater than TH2 but less than TH3, the UE transmits uplink data to the MeNB, SgNB1, and SgNB2. If the UE's uplink data buffer size is greater than TH3, the UE transmits uplink data to both the MeNB and SgNB1, SgNB2, and SgNB3.

[0542] The priority order can be notified along with the threshold. Alternatively, it can be notified separately from the threshold. The priority order of each SgNB can be changed. Changing the priority order of each SgNB based on the communication status between each SgNB and the UE can improve uplink communication throughput.

[0543] The above example discloses the following scenario: when the UE's uplink data buffer is below a specified threshold, the UE initiates uplink transmission from the MeNB. As another example, transmission can be sent to the SgNB when the data is below the specified threshold, and to the MeNB when the data is above the threshold. The MeNB can configure which MeNB and SgNB to transmit uplink data to for the UE when the data is below or above the threshold. The MeNB can be included to set priority and notify the UE. By using the SgNB from an earlier stage, uplink data throughput is improved.

[0544] When the UE is configured to use the MC of multiple SgNBs for the MeNB, the UE can route data from the upper layer between the MeNB and all SgNBs. The routing function can appropriately apply the methods described above. Alternatively, the data forking method described in the uplink can be applied to route between the used MeNBs or SgNBs. The SgNBs to which the forking occurs can be flexibly configured.

[0545] The method for initiating uplink data transmission from the UE to the base station is disclosed. The UE notifies the base station of a scheduling request (SR). In addition, the UE may notify the base station of a buffer status report (BSR).

[0546] The UE notifies the SgNB of the uplink transmission of SR and BSR. Therefore, SR and BSR can be processed in the lower layer that exists in each SgNB.

[0547] Alternatively, the UE can notify the MeNB of an SR or BSR for an SgNB that is transmitting uplink data. This notification may include information indicating which SgNB the SR or BSR is for. This information may be an SgNB identifier. Upon receiving an SR or BSR from the UE, the MeNB notifies the SgNB that it is the recipient of the SR or BSR, along with information indicating the content of that SR or BSR. The SgNB receiving this information can use this content to perform uplink scheduling for the UE.

[0548] Therefore, the MeNB can perform uplink scheduling for the UE corresponding to the SR and BSR for each SgNB.

[0549] Alternatively, the UE can notify the MeNB of the uplink SR and BSR to be sent as a bearer with MC configured. It does not notify each SgNB of the SR and BSR to be sent as an uplink bearer with MC configured. The MeNB receiving this notification uses a pre-defined threshold to determine which SgNB should perform uplink scheduling. The MeNB can then notify the SgNB performing uplink scheduling of an uplink scheduling start request.

[0550] The MeNB can notify the SgNB of the SR and BSR information obtained from the UE. Alternatively, the MeNB can derive the data capacity required for uplink scheduling using the SgNB and notify the SgNB of this derived result. Therefore, the UE does not need to notify each SgNB of its SR and BSR. The UE only needs to notify the MeNB of the SR and BSR sent as uplinks for bearers with configured MCs. This capability map reduces UE power consumption.

[0551] The secondary base station used by the MC can be an eNB that serves as an LTE base station. Both eNBs and gNBs can be used. The method disclosed in Embodiment 6 can be appropriately applied. In Embodiment 6, the secondary base station does not use a new AS sublayer, therefore an eNB can be used.

[0552] By employing the method disclosed in Embodiment 6, a UE can be configured to connect to a primary base station and multiple secondary base stations. This increases the communication throughput provided to the UE. Furthermore, by connecting to multiple base stations, reliability is improved.

[0553] Variation 1 of Implementation Method 6.

[0554] In 3GPP, a new AS sublayer protocol was discussed as the NR protocol (see Non-Patent Document 9 (TR38.804 V.14.0.0)). The new AS sublayer protocol is also known as SDAP (Service Data Adaptation Protocol). In this specification, the new AS sublayer is also referred to as the new AS layer. In the new AS sublayer, PDU session data is mapped to the DRB.

[0555] As a QoS architecture in NG-CN and NR, the following is proposed: A PDU session can be mapped to more than one DRB. Different PDU sessions are mapped to different DRBs. A PDU session constitutes multiple QoS flows. A DRB can be mapped to more than one QoS flow.

[0556] The host device assigns QoS tags to the PDU session data based on QoS. A QoS flow identifier is proposed as the QoS tag. The gNB establishes a DRB based on the QoS of the PDU session data, and in the new AS sublayer, the mapping between the PDU session data and the DRB is performed based on the QoS flow identifier.

[0557] Figure 21 This diagram illustrates the architecture and data flow when the upper-level NW is NG-CN and the base station is NR for a gNB. In 3GPP, the core network of 5G is called "Next Generation Core Network" (NG-CN). The NG-CN comprises the Access & Mobility Management Function (AMF), the Session Management Function (SMF), and the User Plane Function (UPF).

[0558] The AMF and gNB are connected via the N2 interface. The UPF and SMF are connected via the N3 interface. The SMF and UPF are connected via the N4 interface. Sometimes the AMF and SMF are connected via the N11 interface.

[0559] In addition to PDCP, RLC, MAC, and PHY, gNB also has a New AS Layer. The gNB's New AS Layer connects to the upper-level NW in each PDU session. Figure 21 The diagram illustrates the case where a PDU session constitutes one DRB, and the case where a PDU session constitutes two DRBs.

[0560] Figure 21 In the example, the correspondence of QoS flows is illustrated when a PDU session constitutes two DRBs. Figure 21In this context, a PDU session contains three QoS flows: QoS flow 1, QoS flow 2, and QoS flow 3. The gNB sets DRB1 for QoS flow 1 and QoS flow 2, and maps them to DRB1 in the new AS layer. The gNB sets DRB2 for QoS flow 3, and maps it to DRB2 in the new AS layer.

[0561] In gNB, QoS flow 1 and QoS flow 2 data are processed through the DRB1 setting, while QoS flow 3 data is processed through the DRB2 setting.

[0562] The DC in the presence of a New AS sublayer protocol was discussed (refer to Non-Patent Document 28 (TS37.340V0.2.0(2017-06)10.2.2MR-DC with 5GC)). However, the details of the MC in the presence of a New AS sublayer protocol have not been discussed. In this variation 1 of Embodiment 6, a method for implementing the MC in the presence of a New AS sublayer protocol is disclosed. The case of MCG fork bearer is shown.

[0563] Figure 22 This diagram illustrates the architecture of the MC (Multi-Channel Network). It shows the following configuration: the upper-level NW (Network Wireless Terminal) is NG-CN (NG-CN), the primary base station is the base station (gNB) in the NR (Non-Regional Base Station), and the secondary base station is the base station (gNB) in the NR. The primary base station of the NR is referred to as MgNB, and the secondary base station of the NR is referred to as SgNB. The gNB's protocol structure consists of a new AS sublayer, PDCP (Programmable Path Control), RLC (Remote Control Library), MAC (Machine Interface), and PHY (Physical Hybrid). A new AS sublayer is located above the PDCP.

[0564] in addition, Figure 22 In this case, the primary base station is set as the gNB in ​​NR, but it is also possible to set the eNB with a new AS sublayer in the base station in LTE as the primary base station.

[0565] Figure 22 This diagram illustrates the architecture on the base station side, but the architecture on the UE side is the same except for the upper-level NW. In one UE, a new AS sublayer and PDCP are formed, as well as RLC, MAC, and PHY for the MgNB, and RLC, MAC, and PHY for each SgNB set as MC.

[0566] Figure 22This illustrates a scenario using MCG forked bearers. The upper-level NW is connected to the MgNB, and the SgNB used by the MC is connected to the MgNB. Downlink data is mapped to DRBs in the MgNB's new AS layer based on the QoS flow identifier, and processed by the PDCP in each mapped DRB. Even if there are multiple SgNBs, each data item is assigned a consecutive sequence number (SN) in the PDCP. The data with assigned SNs is forked into the MgNB and each SgNB. The forked data is sent to the RLCs of the MgNB and each SgNB, processed by the RLCs, MAC, and PHYs of the MgNB and each SgNB, and then sent to the UE.

[0567] Data received by the UE from the MgNB and each SgNB is processed by the PHY, MAC, and RLC of the MgNB and each SgNB, and then transmitted to the PDCP. In the PDCP, the data is reordered based on the SN assigned to the data transmitted from the MgNB and each SgNB, and then transmitted to the new AS sublayer. The new AS sublayer separates the data into QoS streams according to the QoS stream identifier and transmits them to the upper layer.

[0568] For uplink data, in the UE, data from the upper layer is mapped to DRBs in the New AS sublayer according to the QoS flow identifier, and processed by the PDCP in each mapped DRB. Similar to the downlink, even if there are multiple SgNBs, each data item is assigned a consecutive sequence number (SN) in the PDCP. Data with assigned SNs is then branched for transmission via RLCs used by the MgNB and each SgNB. The transmitted data is processed by the RLCs, MAC, and PHYs used by the MgNB and each SgNB, and then sent to the MgNB and each SgNB.

[0569] Data received from the UE by the MgNB and each SgNB is processed by the PHY, MAC, and RLC of the MgNB and each SgNB, and then transmitted to the PDCP of the MgNB. In the MgNB's PDCP, the data is reordered based on the SN assigned to it and transmitted to the new AS sublayer. The new AS sublayer separates the data into QoS streams according to the QoS stream identifier and transmits them to the upper-level NW.

[0570] The method for configuring MCs is disclosed. MCs are configured per DRB. MCs using MCG forks are configured per DRB.

[0571] Figure 23 This diagram illustrates the data flow when an MC is configured for each DRB. The DBR with the configured MC is set as DRB1. The QoS flows mapped to DRB1 are designated as QoS Flow 1 and QoS Flow 2. For DRB1, MgNB, SgNB1, SgNB2, and SgNB3 are used for MCs based on MCG fork bearers.

[0572] QoS Flow 1 and QoS Flow 2 data mapped to DRB1 are forked and routed to MgNB and each SgNB via PDCP. In the uplink data, similarly to the downlink, QoS Flow 1 and QoS Flow 2 data mapped from the UE to DRB1 are forked and routed to MgNB and each SgNB via RLC via PDCP.

[0573] In the uplink, the default DBR can be used instead of the DRB1 set in the downlink. In this case, the data of QoS flow 1 and QoS flow 2, which are generated by the UE using the default DRB, can be forked via PDCP and routed to the RLCs of the MgNB and each SgNB. In the MgNB, the data from the MgNB and each SgNB is reordered using the SN via PDCP, and the data is separated into QoS flows by the QoS flow identifier using the new AS layer. The separated data is then transmitted to the upper-level NW.

[0574] Therefore, by setting MC for each DRB, MC can be set without changing the mapping relationship between DRBs and QoS flows set in the state without MC. This avoids the complexity of MC control.

[0575] The process for setting MC for each DRB can apply the process disclosed in Implementation 6. For example, it can be done in... Figure 19 and Figure 20 In the SgNB append request of steps ST4203 and ST4215 of the process shown, the MeNB notifies each SgNB that has set the MC of QoS flow characteristic information.

[0576] Here are six examples of QoS flow characteristic information.

[0577] (1) Bearing identifier.

[0578] (2) Load-bearing structure.

[0579] (3) QoS flow identifier.

[0580] (4) QoS distribution of each QoS stream.

[0581] (5) PDU session identifier.

[0582] (6)(1) to (5) combinations.

[0583] The MgNB can notify each SgNB that has set the MC of the QoS distribution for each QoS flow requested by each SgNB. The MgNB can determine the QoS distribution settings for each SgNB that sets the MC to meet the QoS distribution requirements of the MC's QoS flows.

[0584] The MgNB can notify each SgNB that has set the MC of the requested bearer structure. The MgNB can set its bearer structure to be the same as its own. Alternatively, it can determine the bearer structure such that the bearer structure of the MgNB and the bearer structure of the SgNB setting the MC satisfy the QoS distribution of the QoS flows for the MC.

[0585] Upon receiving an append request from the SgNB, the SgNB uses the QoS flow characteristic information contained in the append request to determine the AS settings for the bearer of the MC. Each SgNB then notifies the MgNB of the determined AS settings.

[0586] Therefore, when a new AS sublayer is required, the MgNB can set the MC for each DRB for the UE. Between the MgNB and the UE, and between each SgNB and the UE, MCG forked bearers can be used to perform the MC for each bearer.

[0587] Regarding the data forking method in the uplink of MC, the method disclosed in Implementation 6 can be appropriately applied.

[0588] Regarding the method for initiating the transmission of uplink data from the UE to the base station, the method disclosed in Implementation Method 6 can be appropriately applied. SR and BSR for each QoS flow can be set and notified from the UE to the base station.

[0589] Other methods for configuring MC are disclosed. MC is configured on a per-QoS flow basis. For one or more QoS flows within a QoS flow mapped to the DRB in a new AS sublayer, MC is configured using MCG fork bearers.

[0590] Figure 24 This is a schematic diagram illustrating the data flow when MC is set for each QoS flow. The QoS flow undergoing MC is set as QoS flow 1. MgNB only branches and routes QoS flow 1 in DRB1.

[0591] The method for identifying publicly forked data is as follows: The MgNB determines whether a fork has occurred by assigning a QoS flow identifier to the data. The same applies to uplink data; the UE determines whether a fork has occurred by assigning a QoS flow identifier to the data.

[0592] For example, if the data from the PDCP in the MgNB contains the identifier of QoS flow 1, the MgNB determines that the data should be forked to the SgNB, and performs forking and routing for each SgNB. The same applies to uplink data. If the data from the PDCP in the UE contains the identifier of QoS flow 1, it determines that the data should be forked to the RLC used by the SgNB, and performs forking and routing for each SgNB's RLC.

[0593] Therefore, MCs using MCG fork bearers can be used for each QoS flow.

[0594] Alternatively, information regarding whether to perform forking can be configured separately. This information can be appended to the upper-level NW or data from the upper-level layer via a new AS layer. Alternatively, it can be appended via the PDCP layer. QoS flow identifiers can be used. Appending information to the QoS flow identifier data indicating forking indicates that forking is occurring. Appending information to the QoS flow identifier data indicating that forking is not occurring indicates that forking is not occurring.

[0595] Alternatively, information about whether or not to fork can be appended to the data. Thus, forking or routing functions can use the forked information appended to the data to determine whether data is forked or routed.

[0596] By attaching fork information through the MgNB or UE's new AS layer or PDCP layer, the fork information can be configured for use within the RAN. This allows fork or routing functions to avoid interpreting QoS flow identifiers assigned by the upper-level NW or upper-level layer, simplifying the process.

[0597] The procedure for setting the MC per QoS flow can be applied to the procedure for setting the MC per DRB. The MgNB needs to notify the UE of the MC setting per QoS flow. Therefore, for example, in Figure 19 and Figure 20 In step ST4302 of the illustrated process, the MgNB notifies the MC of the QoS flow settings. The QoS flow identifier for the MC can be notified. Similarly, notifications from the MgNB regarding the UE's SCG structure and bearer structure can also be performed.

[0598] Therefore, the MgNB can set the MC for each QoS flow for the UE. The MC fork can be used for each QoS flow between the MgNB and the UE, and between each SgNB and the UE.

[0599] Other methods for performing MC on a per-QoS flow basis are disclosed. An additional DRB is set for the QoS flow to be MCed. The QoS flow to be MCed is mapped to the additionally set DRB. By setting the additionally set DRB to the MC, MC can be set for the QoS flow mapped to that DRB.

[0600] Figure 25 This is a schematic diagram illustrating the data flow when a DRB is added to map the QoS stream performing MC. The QoS stream performing MC is set to QoS stream 1.

[0601] Configure the mapping relationship between the QoS flow before MC and the DRB as follows: Figure 21 The relationship is shown below. Before MC is set, QoS flow 1 and QoS flow 2 are mapped to DRB1.

[0602] like Figure 25 As shown, in order to configure QoS flow 1 for MC, MgNB adds a configuration for mapping QoS flow 1 to DRBX1. The new AS sublayer maps QoS flow 1 to DRBX1. QoS flow 2 is mapped to DRB1 in the same way as before MC configuration.

[0603] Therefore, DRBX1 is mapped to a QoS flow that undergoes MC (Matching Control). MgNB configures MC for DRBX1. Thus, QoS flow 1 mapped to DRBX1 undergoes MC. Since MC is performed on the MCG (Matching Control Group) fork-bearer, MgNB only needs to fork and route the data for QoS flow 1.

[0604] The added DRB structure can be configured using the QoS distribution of the branched QoS flows. The QoS distribution of the QoS flows can be used, as notified from the upper-level NW. DRBX1 is added via MgNB, and the data of QoS flow 1 is mapped to DRBX1 using the new AS sublayer. The new AS sublayer determines which DRB to map to based on the QoS flow identifier assigned to the data by the upper-level NW.

[0605] The MgNB configures DRBX1 to use the MC for branching and bearer. For QoS flow 1 data, the MC performs branching to the SgNB side and routing to SgNB1, SgNB2, and SgNB3.

[0606] The MgNB can add a DRBX1 structure for MC (Multi-Channel Memory) to the UE notification. This notification can, for example, use the method disclosed in Implementation 6 for MC of the UE notification from the MgNB using a DRB structure.

[0607] The MgNB can notify the UE of the mapping relationship between QoS flows and DRBs in the new AS layer. For example, it can associate the DRB identifier, DRB structure information, QoS flow identifier, QoS distribution, etc., in the notification. Here, the notification represents the mapping relationship information between QoS flow 1 mapped to DRBX1. Thus, the UE can map QoS flow 1 to DRBX1 in the new AS sublayer.

[0608] Therefore, the UE can add and configure DRBs for QoS flows that perform MC, and can configure and implement MC for these DRBs. The same applies to uplink data.

[0609] Data for QoS stream 2 is mapped to DRB1 by the new AS sublayer. The structure of DRB1 can be left unchanged. The structure of DRB1 corresponds to QoS stream 2 before MC settings are configured; therefore, it will correspond to QoS stream 2 even without changes. DRB1 does not have MC settings configured; therefore, MC is not configured for QoS stream 2 data, and communication is performed solely using MgNB.

[0610] The MgNB can notify the UE of QoS flow information mapped to DRB1. Through additional settings on DRBX1, the QoS flow mapped to DRB1 can be changed from QoS flow 1 and QoS flow 2 before MC settings to QoS flow 2. The MgNB notifies the UE of the QoS flow changes or reconfigurations, thus enabling the UE to identify the QoS flow mapped to DRB1.

[0611] Notifications of changes or reconfigurations to QoS flows mapped to the DRB can be sent using RRC signaling. This notification can be sent within the same signaling used for appending configurations to DRBX1.

[0612] MgNB can reconfigure DRB1. For example, DRB1 can be reconfigured to make it a suitable DRB structure for QoS flow 2 mapped to DRB1 after MC configuration. The QoS distribution of QoS flow 2 can be used for configuration. MgNB reconfigures DRB1, using a new AS sublayer to map the data of QoS flow 2 to DRB1.

[0613] The MgNB can notify the UE of the reconfigured DRB1 structure. This notification can, for example, employ the method disclosed in Implementation 6 for notifying the UE of its DRB structure from the MgNB. The UE can then reconfigure the DRB1 structure. The same applies to uplink data. Thus, a suitable DRB structure can be implemented based on changes in the mapped QoS flow.

[0614] As a method for resetting the DRB of mapped QoS flows, the aforementioned DRB can be added or deleted. A suitable DRB structure can be set according to changes in the mapped QoS flows.

[0615] Figure 26 and Figure 27 This is an example of a process for setting the MC for each QoS flow. Figure 26 and Figure 27 Connect at the boundary line BL2627. Figure 26 and Figure 27 This illustrates the MgNB's append settings for the DRB containing the QoS flow undergoing MC (Modified Control Point). In step ST4901, data communication occurs between the UE and the MgNB. In step ST4902, the MgNB determines whether to implement MC for each QoS flow on the UE. In step ST4903, the MgNB determines the append settings for the DRB mapped to the QoS flow undergoing MC. In step ST4904, the MgNB determines and appends the structure of the DRB for the QoS flow undergoing MC.

[0616] In step ST4905, the MgNB notifies the UE of the added DRB structure and the QoS flow identifier mapped to the added DRB. The QoS distribution of the QoS flow can be notified. Furthermore, the MgNB can notify the UE of a new data transmission abort indication for the QoS flow in the DRB that was mapped to the QoS flow before the additional configuration. This indication can be notified using RRC signaling. For example, the above information can be included in the RRC connection reconfiguration.

[0617] The UE uses the information received from the MgNB to perform the configuration, and in step ST4906, notifies the MgNB that the configuration is complete. This configuration completion can be notified, for example, via RRC connection reconfiguration signaling.

[0618] In step ST4907, the UE suspends new data transmission for the QoS flow in the DRB that was mapped to the QoS flow before the additional configuration. Furthermore, the UE uses the DRB structure obtained from the MgNB notification to perform the additional configuration, mapping the QoS flow mapped to the additional DRB to that additional DRB to begin data transmission. In step ST4908, the MgNB maps the QoS flow mapped to the additional DRB to that additional DRB to begin data transmission.

[0619] Furthermore, the DRB set before the append configuration can be maintained even without mapped QoS. By maintaining this, processing of data before transmission was interrupted can be performed. For example, retransmission processing at the lower layer can be implemented. The UE can insert a marker at the end of the data transmitted using the DRB set before the append configuration. Finally, data as a marker can be transmitted. This marker is called the end marker.

[0620] In step ST4909, QoS flow data communication is performed using the DRB added between the UE and MgNB. Alternatively, in step ST4909, QoS flow data communication in the DRB before the addition of the configuration can also be performed. In step ST4910, the MgNB determines whether data processing in the DRB before the addition of the configuration has ended. An end flag can be used for this determination. If not, the process returns to step ST4909 and performs data processing. If it has ended, in step ST4911, the DRB configuration before the addition of the configuration is removed.

[0621] In step ST4912, the MgNB notifies the UE of the cancellation of the DBR settings prior to the additional settings. This cancellation can be notified via RRC signaling. For example, the cancellation can be included in an RRC connection reconfiguration. Upon receiving the cancellation notification of the DBR settings prior to the additional settings, the UE cancels the previous DBR settings.

[0622] The MgNB can insert an end marker at the end of the data transmitted via the DRB before the setting. The UE can release the DRB setting if it receives the end marker, or wait for the DRB setting to be released until it is received, and then release the DRB setting after receiving the end marker.

[0623] Additionally, an example of deleting the DRB before the additional configuration is disclosed. However, if there is a QoS mapping to the DRB before the additional configuration, it is not necessary to delete the DRB before the additional configuration. Furthermore, when reconfiguring the DRB before the additional configuration, the MgNB can notify the UE of the reconfigured DRB structure.

[0624] As a protocol stack for inserting end markers, for example, the end marker can be inserted by a new AS sublayer. An end marker can be inserted for all QoS flows mapped to an appended DRB, simplifying control. Alternatively, an end marker can be inserted for each QoS flow, allowing for flexible control of each QoS flow and reducing malfunctions.

[0625] In step ST4914, the MgNB begins to add MC settings for the DRB to perform QoS flow for MC. In step ST4915, the MgNB, SgNB1 and SgNB2 used in MC, and the UE perform MC setting processes among themselves. This MC setting process can be performed using the method disclosed in Embodiment 6. Since a radio bearer for QoS flow for MC is set, the method for setting MC can be applied to that radio bearer.

[0626] A method for additionally setting DRBs for QoS flows with MCs set for each QoS flow is disclosed. In this case, for a QoS flow, data from the DRB before the additional setting and data from the DRB after the additional setting are transmitted to the new AS sublayer. In this case, although reordering is performed in the PDCP of each DRB, no reordering is performed in subsequent packet data.

[0627] Therefore, when the order of PDCP data from the pre-configuration DRB and the newly configured DRB differs, a problem arises where the data cannot be reordered in the new AS sublayer. This results in a failure to ensure the correct sequence of events.

[0628] A solution to the above problem is disclosed. A sequence number is appended to the data in the new AS sublayer. A sequence number can be set for each QoS flow and appended to the data. The new AS sublayer can use this sequence number to reorder data received from PDCP.

[0629] Other methods are disclosed. Utilizing the aforementioned end marker, the PDCP data from the appended DRB up to the point of receiving the end marker is stored and maintained. A buffer for this data storage and maintenance can be configured. After processing and transmitting the data from the DRB before the append setting up to the end marker to the upper-level NW or upper-level layer, if an end marker appears, the PDCP data from the appended DRB can be processed and transmitted to the upper-level NW or upper-level layer.

[0630] Therefore, the correct order of the grouped data can be ensured.

[0631] The cache used to store this data can be set in the new AS sublayer, and these processes can be performed by the new AS sublayer.

[0632] Regarding the data forking method in the uplink of the MC, the method disclosed in Implementation 6 can be appropriately applied. This can be applied to the MgNB and the SgNB, which sets the MC for each QoS flow.

[0633] Regarding the method for initiating the transmission of uplink data from the UE to the base station, the method disclosed in Implementation Method 6 can be appropriately applied. This can be applied to the MgNB and the SgNB, which sets the MC for each QoS flow. The SR and BSR for each QoS flow can be set and notified from the UE to the base station.

[0634] By employing the above method, the MgNB can implement MC for each QoS flow of the UE. Since MC can be implemented for each QoS flow, MC control can be implemented with finer QoS precision compared to MC for each bearer.

[0635] Embodiment 6 discloses a routing function for the MgNB to each SgNB that has a configured MC. Therefore, the situation of setting a routing function for the MgNB can also be applied to this variation 1 of Embodiment 6. Furthermore, a function can be set to route to different SgNBs for each QoS flow. When there are multiple QoS flows performing MCs, the MgNB can route to different SgNBs for each QoS flow. The MgNB can use the QoS flow identifier to determine which SgNB to route to.

[0636] The MgNB can configure the mapping between QoS flows and the SgNBs that perform routing. The MgNB can notify the UE of this mapping. This notification can be done using RRC signaling. For example, the mapping can be included in the RRC connection reconfiguration. The mapping can also be notified when configuring the MC for the UE. The MgNB can also configure the mapping between QoS flows and the SgNBs that send data for the UE.

[0637] The UE can configure the mapping between QoS flows and the SgNBs that perform routing. The UE can notify the MgNB of this mapping. This notification can be done using RRC signaling. For example, the mapping can be included in the RRC connection reconfiguration completion notification. The UE can request the MgNB which SgNB to use for each QoS flow.

[0638] When routing to different SgNBs for each QoS flow, the MgNB can notify the QoS distribution of the corresponding QoS flow in an append request to the SgNB. Each SgNB can use the DRB settings corresponding to the notified QoS distribution. Each SgNB notifies the MgNB of the DRB settings corresponding to the QoS distribution. The MgNB can notify the UE of the DRB settings received from the SgNB as DRB settings for use by the MC. Notification from the MgNB to the UE can use RRC signaling. For example, the DRB settings corresponding to the QoS distribution can be notified via RRC connection reconfiguration.

[0639] Therefore, the DRB structure in the SgNB that routes per QoS flow can be configured to suit the QoS settings of the routed QoS flow. An MC can be configured that uses an SgNB with a DRB structure suitable for each QoS flow.

[0640] The secondary base station used by the MC can be an eNB that serves as an LTE base station. Both eNBs and gNBs can be used. The method disclosed in this variation 1 of embodiment 6 can be appropriately applied. In this variation 1, the secondary base station does not use a new AS sublayer, therefore an eNB can be used.

[0641] By employing the method disclosed in this variant 1 of embodiment 6, even when the upper-level NW is NG-CN, a UE can be configured to connect to one primary base station and multiple secondary base stations. This increases the communication throughput provided to the UE. Furthermore, by connecting to multiple base stations, reliability is improved.

[0642] Implementation Method 7.

[0643] As mentioned above, Non-Patent Document 27 (R2-167583) proposes a method for supporting MCs using SCG bearers. In MCs using SCG bearers, methods for connecting to upper-level network controllers (NWs), the architecture including the upper-level NWs, and configuration methods are required. For example, when multiple SgNBs are used for the MC, questions arise regarding how the bearer structure should be structured and how data should be distributed among the multiple SgNBs.

[0644] However, the architecture and configuration method used are not clearly defined in the disclosure of Non-Patent Document 27 and in the prior art. In this embodiment 7, the architecture and configuration method of the MC carried by the SCG are disclosed.

[0645] Figure 28 This is a diagram illustrating the architecture of the MC. It shows the following configuration: the upper-level NW is the EPC, the primary base station is the base station (eNB) in LTE, and the secondary base station is the base station (gNB) in NR. Figure 28 This diagram illustrates the architecture on the base station side, but the architecture on the UE side is the same except for the upper-level NW. For a single UE, PDCP, RLC, MAC, and PHY are configured for each SeNB, set as either MeNB or MC.

[0646] Figure 28 This illustrates a scenario using an SCG bearer. The upper-level NW connects to the SgNB used by the MC. The upper-level NW routes downlink data to the SgNB used by the MC for transmission. This downlink data is transmitted to the PDCP without passing through the new AS sublayer of the SgNB. Data from the upper-level NW can be input to the new AS sublayer of the SgNB, but in this new AS sublayer, the data passes through unprocessed.

[0647] In each SgNB, the PDCP, RLC, MAC, and PHY processes the data and then transmit it to the UE.

[0648] The data received by the UE from each SgNB used by the MC is processed by the PHY, MAC, RLC and PDCP used by each SgNB and then transmitted to the upper layer.

[0649] For uplink data, in the UE, data from the upper layer is routed to each SgNB and transmitted to the PDCP used by each SgNB. The PDCP, RLC, MAC, and PHY used by each SgNB are then processed and sent back to the respective SgNB.

[0650] This document discloses a scenario where the upper-level NW routes data to the MC using SgNBs. Routing functionality to each SgNB is configured on the upper-level NW. Routing functionality can also be configured on the S-GW, which acts as the U-Plane of the upper-level NW. Routing functionality can be added as a feature of the S-GW. The upper-level NW connects to multiple SgNBs to implement MC without altering the E-RAB bearer configured between the upper-level NW and the UE.

[0651] The routing function can support both downlink and uplink. Furthermore, the routing function can include the ability to append sequence numbers to packet data. The routing function uses these sequence numbers for reordering.

[0652] Figure 28 The document describes configuring the routing function between the S-GW and multiple SgNBs on the S-GW. Alternatively, the routing function can be configured on a different node than the S-GW. It is also acceptable not to extend the functionality of the S-GW.

[0653] Furthermore, routing functionality between the S-GW and multiple SgNBs can be configured on the base station side. The routing functionality of any one of the SgNBs used by the MC can be used. Data communication occurs between the S-GW and this single SgNB's routing functionality. The routing functionality of this single SgNB can also be used to route data between other SgNBs.

[0654] Therefore, it is not necessary to expand the functionality of the S-GW; only the functionality of the base station needs to be expanded. As a result, the system construction becomes easier.

[0655] A method for setting up the MC using SCG bearers is disclosed. The method disclosed in Implementation 6 can be used for processing additional requests from the MeNB to the SgNB used in the MC and for the MeNB to set up the MC for the UE.

[0656] This paper discloses a method for data forwarding from a MeNB to an SgNB. Since multiple SgNBs are configured in an MC, determining which SgNB to forward data to becomes a problem. To solve this problem, the MeNB can determine the target SgNB for data forwarding. The MeNB transmits the SN status of the PDCP PDU to the determined SgNB and begins data forwarding. Data forwarding from the MeNB to the SgNB used in the MC can be performed until a path handover occurs.

[0657] The MeNB sets the target SgNB for data forwarding. When a MeNB uses multiple SgNBs for MC (Multi-access Control), a designated SgNB is pre-selected. The MeNB performs SN (Signal Receiver) status transmission and data forwarding for the selected SgNB. The MeNB can notify the selected SgNB that it is the target SgNB for data forwarding in the SgNB append request used for MC. The SgNB can identify data forwarding from the MeNB, thus reducing the occurrence of malfunctions.

[0658] The MeNB can notify the UE of information related to the SgNB specified in the data forwarding target. This notification from the MeNB can be included in the MC settings. The UE identifies which SgNB the data forwarding originates from before data is transmitted. The UE can process data from the SgNB and transmit it to the upper layer before data with routing functionality implemented in the upper-level NW using the MC settings. This ensures the correct ordering of packet data.

[0659] Other methods for public data forwarding. The MeNB can determine the target SgNB for each data packet. In this case, the MeNB also transmits the SN status of the PDCP PDU and forwards the data to the determined SgNB. For example, suppose the MeNB has already sent data up to SN n-1 of the PDCP PDU. When transmitting the next data packet to SgNB1, the SN status n and the next data packet are transmitted to SgNB1. SgNB1 performs PDCP processing on this data packet. At this time, SN n is assigned in the PDCP.

[0660] When transmitting the next packet to SgNB2, the SN status n+1 and the next packet data are transmitted to SgNB2. SgNB2 performs PDCP processing on this packet data. In PDCP, the SN is assigned to n+1. Alternatively, if transmission up to n-1 has ended, n is transmitted as the SN status, but n-1 can also be transmitted. The SgNB receiving the SN status can set n as the SN of the PDCP PDU. Thus, by transmitting the SN for each packet data, data can be transmitted for each packet data across multiple SgNBs. The continuity of the SN in PDCP is maintained.

[0661] Multiple packets can be transmitted consecutively to the SgNB instead of one packet at a time. The MeNB only transmits the first SN (Signal Serial Number) of these consecutive packets to the SgNB. The MeNB counts the number of packets transmitted to the SgNB and uses this count to derive the SN of the next packet to be transmitted to another SgNB. The MeNB then transmits the derived SN status along with the packet data to that other SgNB. This allows multiple packets to be transmitted consecutively to the SgNB. Compared to transmitting the SN per packet, this reduces the amount of information communicated between base stations.

[0662] The UE can use the PDCP's serial number (SN) to reorder packet data. The UE can use the SNs of the MeNB and each SgNB's PDCPs to reorder and transmit them to the higher-level network controller (NW). Alternatively, the UE can notify the higher-level NW of the SN information from the MeNB and each SgNB's PDCPs, and the higher-level NW can use this SN information to reorder the packets. By appending a unified SN to the MeNB and each SgNB, the correct order of the packet data is ensured.

[0663] This document discloses a method for path switching from MeNB to SgNB. The MeNB notifies the MC of the path switching information to the MME. Eleven examples of MC path switching information are shown below.

[0664] (1) Bearer information for path switching.

[0665] (2) Set the identifiers of multiple SgNBs of MC.

[0666] (3) Set the addresses of multiple SgNBs of MC.

[0667] (4) Path switching request.

[0668] (5) Identification of nodes with routing functions.

[0669] (6) The address of the node with routing function.

[0670] (7) Request to start the routing function.

[0671] (8) Set the UE identifier of the MC.

[0672] (9) The identifier of this MeNB.

[0673] (10) The address of this MeNB.

[0674] Combinations of (11)(1) to (10).

[0675] Regarding (1) above, the bearer information for path switching can be the E-RAB bearer information corresponding to the DRB of the configured MC. The E-RAB bearer information may include the E-RAB bearer identifier. The MME can identify the E-RAB bearer of the configured MC.

[0676] Regarding (2) and (3) above, multiple SgNBs that set up the MC can utilize the SgNB of the path switching target. When the S-GW or a node with routing function receives the path switching request mentioned in (4) above, the path is switched to the SgNB of the path switching target.

[0677] The MME will notify the S-GW of the MC path switching information received from the MeNB. The S-GW can then notify nodes with routing capabilities of the MC path switching information. If the S-GW is configured with path switching capabilities, it does not need to notify the MC path switching information. Upon receiving the MC path switching information, the S-GW or a node with routing capabilities will perform path switching from the MeNB to multiple SgNBs configured with MCs and begin routing for these multiple SgNBs.

[0678] When the routing function is configured within a designated SgNB, the MC path switching information can be notified directly from the MeNB to that designated SgNB. This notification can be sent together with the notification of MC path switching information from the MeNB to the S-GW via the MME. The MC path switching information notified from the MeNB to the S-GW via the MME may include the identifier or address of the node with routing function (5) and (6), and the path switching request (4). Based on the path switching request (4), the S-GW performs a path switch from the MeNB to the node with routing function.

[0679] The path switching information notified directly from the MeNB to the specified SgNB may include (2) and (3) the identifiers or addresses of multiple SgNBs of the configured MC, and (7) the routing function activation request. For data received by the specified SgNB from the S-GW, the specified SgNB includes itself in the routing of multiple SgNBs of the configured MC.

[0680] MC path switching information, from MeNB to MME and from MME to S-GW, can be included in the E-RAB correction signaling used for MC configuration. Existing messages can be extended for utilization without requiring the creation of new messages, thus simplifying control.

[0681] As another method, in the path switching settings between the MeNB and the MME, and between the MME and the S-GW, the path switching can be configured one by one for each SgNB used by the MC. In the existing E-RAB correction signaling, the path switching target is a single SgNB, so this can be utilized. This simplifies control by using existing messages.

[0682] When configuring path switching for each SgNB used by the MC, the SgNB that was the target of the previous path switching request can be maintained, and a new SgNB can be added for a new path switching request. As information for path switching, it can be set whether to maintain the information of the SgNB previously set as the target of the path switching. The MeNB notifies the S-GW of this information via the MME, thereby enabling path switching to be configured for multiple SgNBs.

[0683] Figure 29 and Figure 30 This is a diagram illustrating an example of the process for configuring an MC that uses an SCG bearer. Figure 29 and Figure 30 Connect at the boundary line BL2930. Figure 29 and Figure 30 The example shown uses MeNB and two SgNBs (SgNB1, SgNB2). Figure 29 and Figure 30 This demonstrates a method for setting up multiple SgNBs for a single MC configuration. Furthermore, Figure 20 and Figure 30 This illustrates the scenario where the routing function is configured in the S-GW.

[0684] Figure 29 and Figure 30 The process shown includes and Figure 19 and Figure 20 The process shown has the same steps, therefore, the same step numbers are added to the same steps, and common descriptions are omitted.

[0685] In steps ST4207 and ST4219, the MeNB that sent the SgNB reconfiguration completion notification for MC to SgNB1 and SgNB2 transmits the SN status for data transmission to SgNB1 in step ST5201, and starts transmitting data from S-GW to SgNB1 in steps ST5202 and ST5203.

[0686] Figure 29 and Figure 30 Only SgNB1 was transmitted, but the method disclosed above can also be used to transmit data to SgNB1 and SgNB2 on a per-data ...

[0687] In step ST5204, the MeNB notifies the MME of E-RAB correction signaling. The MeNB includes the MC path handover configuration information in the E-RAB correction signaling. In step ST5205, the MME notifies the S-GW of bearer correction signaling containing the MC path handover configuration information. Thus, the S-GW can identify multiple SgNBs for the path handover target.

[0688] In step ST5205, the MME, which notified the S-GW of the MC path switching configuration information, sent a signaling message to the MeNB informing it that the E-RAB correction was complete. Thus, the MeNB can recognize that path switching has been configured in the MC using SgNB1 and SgNB2.

[0689] In step ST5205, the S-GW, having received the MC path switching configuration information, sends an end-of-transfer packet in step ST5206 as the final packet data to the MeNB and initiates the path switching. In step ST5207, the MeNB transmits the end-of-transfer packet to SgNB1. Thus, SgNB1 recognizes that the data from the MeNB has ended.

[0690] In step ST5209, the S-GW begins data routing between SgNB1 and SgNB2, which have been configured with MC. This enables data communication between the UE and SgNB1 and SgNB2, as well as between SgNB1 and SgNB2 and the S-GW. MCs using SCG bearers are established between the UE and multiple SgNBs used by the MC.

[0691] A routing function for setting up multiple SgNBs used in the MC is disclosed. As information used to determine which SgNB the routing function should send data to, information for routing can be set. For example, it can be set to the downlink data transmission status from the local SgNB to the UE, as disclosed in Implementation 6, which is notified to the MeNB by each SgNB.

[0692] Regarding the data forking method in the uplink of the MC, the method disclosed in Implementation Method 6 can be appropriately applied. This can be applied to the SgNB used by the MC.

[0693] Regarding the method for initiating the transmission of uplink data from the UE to the base station, the method disclosed in Implementation Method 6 can be appropriately applied. This can be applied to MeNBs or SgNBs used by MCs.

[0694] The MeNB determines the route. Each SgNB notifies the MeNB of routing information. The MeNB uses this information to derive, for example, the amount of data routed to each SgNB. The data amount can be the data rate. The derived data amount can be the amount of data sent to each SgNB relative to the total data volume. The MeNB notifies the MME of the amount of data routed to each SgNB. The MME notifies the S-GW of the amount of data routed to each SgNB. The S-GW notifies the routing function of this information. The routing function uses this data amount for routing.

[0695] This allows for adjustment of the amount of data routed to each SgNB. Furthermore, the downlink data transmission status from this SgNB to the UE is notified to the MeNB from each SgNB, enabling the utilization of this downlink data transmission status.

[0696] Alternatively, routing decisions can be made by the MME. Each SgNB notifies the MeNB of routing information, which is then transmitted from the MeNB to the MME. Alternatively, each SgNB may notify the MME of routing information. Similarly, the MME uses this information to derive, for example, the amount of data routed to each SgNB, and notifies the S-GW of the derived data amount. The S-GW then notifies the routing function of this information. The routing function uses this data amount for routing.

[0697] This allows for adjustment of the amount of data routed to each SgNB. Furthermore, by having the MME determine the route, control can be easily achieved when the MME and S-GW are located within the same device.

[0698] Alternatively, route determination can be performed by the S-GW. Each SgNB notifies the MeNB of the routing information, which is then transmitted from the MeNB to the MME and from the MME to the S-GW. Alternatively, each SgNB can notify the MME of the routing information, which is then transmitted from the MME to the S-GW. Or, each SgNB can notify the S-GW of the routing information.

[0699] Similarly, the S-GW uses this information to derive, for example, the amount of data routed to each SgNB. The S-GW notifies the routing function of this information. The routing function uses this data for routing.

[0700] This allows for adjustment of the amount of data routed to each SgNB. Furthermore, by having the S-GW, the host device of the U-Plane, determine the route, data routing control can be implemented within the U-Plane.

[0701] Alternatively, route determination can be performed by nodes with routing capabilities. Each SgNB notifies the MeNB of routing information, which is then transmitted from the MeNB to the MME, from the MME to the S-GW, and from the S-GW to the nodes with routing capabilities. Alternatively, each SgNB notifies the MME of routing information, which is then transmitted from the MME to the S-GW, and from the S-GW to the nodes with routing capabilities. Alternatively, each SgNB may notify the S-GW of routing information, which is then transmitted from the S-GW to the nodes with routing capabilities. Alternatively, routing information may be transmitted from each SgNB to the nodes with routing capabilities.

[0702] Similarly, nodes with routing capabilities use this information to derive, for example, the amount of data routed to each SgNB. Nodes with routing capabilities use this data for routing.

[0703] This allows for adjustment of the amount of data routed to each SgNB. Furthermore, by having nodes with routing capabilities determine the route, data routing can be easily controlled, reducing the occurrence of malfunctions.

[0704] Routing can be performed on a per-data-per-data basis, routing data to each SgNB individually. Alternatively, the same data can be routed to the same SgNB within a specified period. This allows for flexible routing and enables routing tailored to the communication quality conditions of each SgNB.

[0705] The secondary base station used by the MC can be an eNB that serves as an LTE base station. Both eNBs and gNBs can be used. The method disclosed in Embodiment 7 can be appropriately applied. In Embodiment 7, the secondary base station does not use a new AS sublayer, therefore an eNB can be used.

[0706] By employing the method disclosed in Embodiment 7, it is possible to configure a UE to connect to multiple secondary base stations. This increases the communication throughput provided to the UE. Furthermore, by connecting to multiple base stations, reliability is improved. Additionally, since an MC using SCG bearers can be configured, communication can be provided without traversing the MeNB. Therefore, the communication throughput provided to the UE is increased.

[0707] Variation 1 of Implementation Method 7.

[0708] The details of the MC using SCG bearers in the presence of the New AS sublayer protocol have not yet been discussed. In this variation 1 of Implementation 7, an implementation method of the MC using SCG bearers in the presence of the New AS sublayer protocol is disclosed.

[0709] Figure 31 This diagram illustrates the architecture of a Media Center (MC) using SCG as a bearer. The following configuration is shown: the upper-level NW is NG-CN, the primary base station is a base station (gNB) in the NR network, and the secondary base station is a base station (gNB) in the NR network. The primary NR base station is referred to as MgNB, and the secondary NR base station as SgNB. The gNB's protocol structure consists of a new AS sublayer, PDCP, RLC, MAC, and PHY. A new AS sublayer is located above PDCP.

[0710] in addition, Figure 31 In this case, the primary base station is set as the gNB in ​​NR, but it is also possible to set the eNB with a new AS sublayer in the base station in LTE as the primary base station.

[0711] Figure 31 This diagram illustrates the architecture on the base station side, but the architecture on the UE side is the same except for the upper-level NW. In one UE, a new AS sublayer and PDCP are formed, as well as RLC, MAC, and PHY for the MgNB, and RLC, MAC, and PHY for each SgNB set as MC.

[0712] Figure 31 This illustrates a scenario using an SCG bearer. The upper-level NW is connected to the SgNB. The upper-level NW routes downlink data to the SgNB used by the MC for transmission. This data is mapped to a DRB based on the QoS flow identifier in the new AS sublayer of the SgNB, and is processed by the PDCP in each mapped DRB.

[0713] The data is processed by PDCP, RLC, MAC, and PHY in each SgNB for each DRB, and then sent to the UE.

[0714] Data received by the UE from each SgNB used by the MC is processed by the PHY, MAC, RLC, PDCP, and NewAS sublayer used by each SgNB. The NewAS sublayer separates the data into different QoS streams based on the QoS stream identifier and transmits them to the upper layer.

[0715] For uplink data, in the UE, data from the upper layer is mapped to the DRB according to the QoS flow identifier in the new AS sublayer used by the SgNB. In each mapped DRB, it is processed by PDCP, RLC, MAC, and PHY and then sent to each SgNB.

[0716] Data received by each SgNB from the UE is processed by PHY, MAC, RLC, and PDCP, and then transmitted to the New AS sublayer. The New AS sublayer separates the data into different QoS streams based on the QoS stream identifier and transmits them to the upper-level NW.

[0717] The method for configuring the MC using SCG bearers is disclosed. The MC is configured per DRB. The MC using SCG bearers is configured per DRB. When the upper-level NW configures the MC using SCG bearers in the NG-CN, the following main problems arise.

[0718] Previously, a PDU session channel (sometimes called the N3 channel) was established between the UPF and gNB for each PDU session, and communication was conducted between the UPF and gNB. However, when using SCG bearers, the upper-level NW needs to communicate not only with the MgNB but also with the SgNBs. When using SCG bearers in the MC, communication is required not only with the MgNB but also with multiple SgNBs. In this situation, how to handle the PDU session channel becomes a problem.

[0719] Furthermore, other problems arise, such as the need to implement routing for multiple SgNBs used by the MC. The question then becomes where to configure this routing function and what functionality to configure for it.

[0720] In addition, other problems arise, such as the following: The DRB required by the MC must be set in SgNB. How to handle the setting of the DRB required by the MC in SgNB, and the mapping method from the new AS sublayer from SgNB, becomes a problem.

[0721] In this modified example 1 of embodiment 7, a method for solving the above-mentioned problems is disclosed.

[0722] Between the NG-CN and the RAN, multiple PDU session channels can be configured for a single PDU session. The MgNB determines the configuration of multiple PDU session channels. For example, when an MgNB connected to the NG-CN is using an MC with an SCG bearer, it determines the configuration of multiple PDU session channels.

[0723] The MgNB notifies the parent NW of a request to append PDU session channels. This request may include PDU session channel appending information. The MgNB may notify the UPF (User Platform Provider) of this request. Alternatively, the MgNB may notify the parent NW's AMF (Agency Provider Provider) or SMF (Small Provider Provider Provider), which in turn notifies the UPF. Nine examples of PDU session channel appending information are disclosed below.

[0724] (1) PDU session identifier.

[0725] (2) PDU session channel identifier (also known as N3 channel identifier).

[0726] (3) Set the QoS flow identifier for the MC.

[0727] (4) Set the identifier of MC's SgNB.

[0728] (5) Set the address of MC's SgNB.

[0729] (6) Identification of nodes with routing functions.

[0730] (7) The address of a node with routing functionality.

[0731] (8) The mapping method from QoS distribution to QoS flow maintains request information.

[0732] Combinations of (9)(1) to (8).

[0733] The above (1) can be information used to identify a PDU session. Information used to identify a PDU session can be obtained from the upper-level NW notification when the PDU session is established. It can be shown which PDU session channel is added to.

[0734] The above (2) is the information already set for identifying the PDU session channel. The information for identifying the PDU session channel obtained from the upper-level NW notification when the PDU session is established can be used. The already set PDU session channel can be explicitly shown.

[0735] In (3) above, the QoS flow performing MC can be one or more. It can be shown which QoS flow in the PDU session has been transferred to.

[0736] The above (4) is sufficient to identify the SgNB whose PDU session channel is configured by the upper-level NW. For example, when the routing function is set to UPF, a PDU session channel can be configured between the SgNB identified by the notification.

[0737] The above (5) simply shows the address of the SgNB that sets the PDU session channel by the upper-level NW. For example, when the routing function is set to UPF, a PDU session channel can be set between the SgNB and the address obtained from the notification.

[0738] The above (6) is sufficient information for identifying the node, which has the routing function of setting the PDU session channel by the upper-level NW. For example, if the node with routing function is set on the RAN side, a PDU session channel can be set between it and the node with routing function identified by notification.

[0739] The above (7) only shows the address information of the node, which has the routing function of setting the PDU session channel by the upper-level NW. For example, if the node with routing function is set on the RAN side, a PDU session channel can be set between it and the node with routing function whose address is notified.

[0740] The above (8) simply indicates the following: the mapping method for the QoS flow from the QoS distribution to the QoS flow transferred to the additionally configured PDU session channel is set to be the same as before the additional configuration. The upper-level NW can use this information to implement the mapping from the QoS distribution to the QoS flow. Whether to set the mapping method to be the same as before the additional configuration can be determined by the upper-level NW. It is possible to make settings suitable for the upper-level NW.

[0741] If the mapping method is set to be the same as before the append setting, the higher-level NW can notify the MgNB of this. For the SgNB used in the MC, the MgNB can set the mapping from the QoS stream identifier in the new AS sublayer to the DRB to be the same as before the append setting. Setting the SgNB for the MC becomes easier.

[0742] When the mapping method differs from the initial configuration, the higher-level NW notifies the MgNB of the mapping relationship from the reconfigured QoS distribution to the QoS flow. This information can be communicated by associating the QoS flow identifier with the QoS distribution of the QoS flow. The MgNB then notifies the SgNB used in the MC of this information. The SgNB can use this information to configure the mapping from the QoS flow identifier in the new AS sublayer to the DRB.

[0743] If the information in (8) is not included in the PDU session channel append information, the upper-level NW decides whether to set the mapping method to be the same as before the append setting. If the information in (8) is included in the PDU session channel append information, the upper-level NW can set the mapping method to be the same as before the append setting according to the information in (8).

[0744] The timing for publicly adding PDU session channels can be configured. For example, after the MgNB receives an SgNB add request response from the SgNB used in the MC, it notifies the upper-level NW of the PDU session channel addition request. This notification can be made after the SgNB used in the MC is determined, so it is acceptable not to configure unnecessary PDU session channels.

[0745] For example, the MgNB can notify the PDU session channel appending request along with the path switching request to the uplink NW. The path switching request can include the PDU session channel appending request. The signaling of the path switching request can be utilized, thus reducing signaling load.

[0746] The timing for setting additional PDU session channels is not limited to this. After the MgNB decides to use the SgNB's MC, the PDU session channel can be set up before the upper-level NW implements the path switch.

[0747] In response to an append request from the MgNB to a PDU session channel, the upstream NW notifies the MgNB of the append request response for the PDU session channel. The upstream NW may also notify the MgNB of the append request response information for the PDU session channel. Twelve examples of append request response information for the PDU session channel are disclosed below.

[0748] (1) Additional settings completed.

[0749] (2) Add a rejection setting.

[0750] (3) Add additional reasons for refusal.

[0751] (4) PDU session identifier.

[0752] (5) Add the PDU session channel identifier before setting.

[0753] (6) Add a PDU session channel identifier.

[0754] (7) The correspondence between the additional PDU session channel and the SgNB.

[0755] (8) The correspondence information between the additional PDU session channels and QoS flows.

[0756] (9) QoS distribution of QoS streams.

[0757] (10) UPF identification.

[0758] (11) The address of UPF.

[0759] Combinations of (12)(1) to (11).

[0760] The above (6) is the information that MgNB can use to identify the additional PDU session channels.

[0761] The newly added PDU session channel can be set as an append-to-previous PDU session channel, thus functioning as a PDU session sub-channel. One or more PDU session sub-channels can be set for a single PDU session. This allows multiple PDU session channels to be set for a single PDU session without actually setting one PDU session channel. Existing settings of setting one PDU session channel for a single PDU session can also be maintained.

[0762] When a PDU session subchannel is configured, the PDU session subchannel identifier can be used to replace the PDU session channel identifier appended to the request response information in the example. Alternatively, the PDU session channel identifier before the configuration can be notified together. The notification can be associated with the PDU session before the configuration and the PDU session subchannel identifier after the configuration.

[0763] The PDU session subchannel identifier can use the PDU session channel identifier. For example, the PDU session subchannel identifier can be a combination of the PDU session channel identifier and a sub-number. For instance, PDU session subchannel identifier = PDU session channel identifier + sub-number. As information used to identify the PDU session subchannel, only the sub-number needs to be notified, thus reducing the amount of information.

[0764] Furthermore, when multiple SgNBs are used for MC, only a PDU session sub-channel needs to be set up for each SgNB. Therefore, the PDU session channel identifier does not need to be increased.

[0765] When the MgNB notifies the upstream NW of the PDU session channel append request along with the path switching request, the upstream NW can include the PDU session channel append request response information in the path switching request response. This can reduce signaling load.

[0766] By using the above method, a PDU session channel can be added between the upper-level NW and the SgNB used for MC. By using the added PDU session channel, communication can be established between the upper-level NW and the SgNB. Therefore, MC using SCG bearers can be executed.

[0767] Routing functionality is required for multiple SgNBs used by the MC. Regarding the location and function of the routing functionality, the routing functionality disclosed in Implementation 7 can be appropriately applied. In Implementation 7, the upper-level NW is set to EPC, but in this variation 1 of Implementation 7, the upper-level NW can be set to NG-CN.

[0768] Implementation 7 discloses a case where, since the upper-level NW is an EPC, the upper-level NW is connected to multiple SgNBs without changing the E-RAB bearer settings. Since the upper-level NW in this variation 1 of Implementation 7 is an NG-CN, no E-RAB bearer settings are performed, and QoS flow settings are used between the upper-level NW and the RAN.

[0769] Routing functionality can be configured on the upper-level NW side. For example, routing functionality can be configured on the UPF. Alternatively, routing functionality can be configured within the UPF's features. When routing functionality is configured on the UPF, a PDU session channel can be added between the UPF and each SgNB used by the MC. The method for adding and configuring the PDU session channel described above can be applied.

[0770] Routing functionality can be configured separately from the upper-level NW. Routing functionality can be configured on the RAN-side node. For example, routing can be configured as a feature of the SgNB. When routing functionality is configured on the RAN-side node, a PDU session channel is added between the UPF and the RAN-side node. Even when using multiple SgNBs for MC, only one PDU session channel needs to be added.

[0771] Data transmission is possible between the UPF and the RAN side node with routing capabilities. Only one PDU session channel needs to be added, thus simplifying the structure of the system that includes the upper-level NW.

[0772] Data transmission between RAN-side nodes with routing capabilities and SgNBs used for MC can utilize the inter-base station interface. For example, this could be Xn, etc.

[0773] As a method for setting up routing functionality for nodes on the RAN side, routing functionality can be set up between the new AS sublayer and the upper-level NW. Data from the upper-level NW is routed during the packet data stage before processing by the new AS sublayer. Furthermore, packet data from the new AS layer of each SgNB used by the MC is reordered based on the SN attached by the routing functionality and transmitted to the upper-level NW.

[0774] As another method for configuring routing for nodes on the RAN side, routing functionality can be established between the New AS sublayer and the PDCP. Data from the upper-level NW is routed to the PDCP of each SgNB used by the MC during the data processing stage of the New AS sublayer. Furthermore, data from the PDCP of each SgNB used by the MC is reordered based on the SN attached by the routing function and then transmitted to the New AS layer.

[0775] A DRB can be configured for each SgNB used by the MC. For example, the DRB can be configured based on the load conditions of the SgNB. Alternatively, a DRB can be configured for the SgNB that performs routing functions. Each SgNB used by the MC communicates within this DRB. The DRB structure of each SgNB can be configured so that the QoS distribution of all SgNBs used by the MC becomes the DRB used for SCG bearers, or becomes the desired QoS of the QoS flow.

[0776] When routing functionality is configured on the RAN side, the question arises as to which gNB should have this functionality configured. This is because gNBs with routing functionality are not limited to SgNBs within the MC. Therefore, routing functionality can be pre-configured for gNBs. This allows routing functionality to be enabled or disabled.

[0777] The method for configuring an SgNB with routing functionality enabled is disclosed. Subsequently, an SgNB with routing functionality enabled is sometimes referred to as an R-SgNB.

[0778] The higher-level NW determines the R-SgNB. The higher-level NW can be determined by either the AMF or the SMF. For example, the R-SgNB can be determined during the PDU session channel addition configuration. The AMF determines the R-SgNB connected to the UPF using the SgNB identifier for the MC included in the PDU session channel addition information notified to the AMF from the MgNB. The AMF notifies the MgNB of the R-SgNB identifier. The R-SgNB identifier can be included in the PDU session channel addition request response information for notification.

[0779] The MgNB responds to the R-SgNB's notification of a PDU session channel appending request. Upon receiving this notification, the R-SgNB can use the PDU session channel appended to the PDU session, which includes QoS flows used for MC, to connect to the UPF. The MgNB can also notify the R-SgNB of a route implementation request between the UPF and the MC-using SgNB. This implementation request can include information about the MgNB itself and information about the MC-using SgNB.

[0780] Information related to this SgNB includes its identifier and address. Information related to the MC-based SgNB includes its identifier and address. Upon receiving this implementation request, the R-SgNB enables routing and routes data for QoS flows communicating using this PDU session channel to the MC-based SgNB.

[0781] The MgNB can summarize and notify the R-SgNB of the PDU session channel append request response information and the route implementation request between the UPF and the MC-using SgNB. Alternatively, the notification of the PDU session channel append request response information, as well as the notification of information about this SgNB and the MC-using SgNB, can be set as a route implementation request between the UPF and the MC-using SgNB. Since this can be notified as a single signaling, the capability map achieves a reduction in signaling volume.

[0782] The AMF notifies the UPF of at least one of the R-SgNB's identifier and address in the PDU session channel append information. This allows the UPF to connect to the R-SgNB using the PDU session channel appended to the PDU session, which includes QoS flows undergoing MC (Matchmaking Control). Communication between the R-SgNB and the UPF is then possible. This information can, for example, be included in a path switching request notified from the AMF to the UPF.

[0783] The method of notifying the UPF from the AMF is disclosed, but it is also possible to notify the UPF from the AMF via the SMF. For example, this can be done when there is no direct interface between the AMF and the UPF.

[0784] The AMF can notify the MgNB of the stop operation of the R-SgNB. The AMF also notifies the UPF of the stop operation of the R-SgNB. The MgNB notifies the R-SgNB of a stop request for routing between the UPF and the MC using the R-SgNB. Upon receiving the stop request, the R-SgNB disables its routing function to stop routing.

[0785] The R-SgNB can be reconfigured. The AMF determines the change of the R-SgNB connected to the UPF. The AMF notifies the MgNB of the R-SgNB change. This notification can use the aforementioned R-SgNB configuration notification. The changed R-SgNB can be notified as the configuration target. Information related to the previous R-SgNB can also be notified at the same time.

[0786] The MgNB notifies the previous R-SgNB of a route stop request between the UPF and the MC using the SgNB. Upon receiving this stop request, the R-SgNB disables its routing function to stop routing. The MgNB then notifies the new R-SgNB of a route implementation request between the UPF and the MC using the SgNB. This notification can use the same route implementation request notification as described above. Upon receiving the implementation request, the R-SgNB enables its routing function to perform routing.

[0787] AMF also notifies UPF of changes to the R-SgNB. This notification can be an additional notification via the PDU session channel with the R-SgNB mentioned above. The changed R-SgNB can be notified as the target. Information related to the previous R-SgNB can also be notified at the same time. UPF can use the PDU session channel that is the target to change the connection from the previous R-SgNB to the changed R-SgNB. Communication between the changed R-SgNB and UPF is possible.

[0788] On the RAN side, the function to stop routing to a subset of SgNBs can be configured. The MgNB can notify the R-SgNB of a route stop request between the UPF and MC using the SgNB, along with information about the SgNB whose route is being stopped, or information about the SgNB whose route is being continued. Upon receiving the stop request, the R-SgNB stops routing to the SgNB that is targeted for the stop request.

[0789] The MgNB can determine the R-SgNB. The MgNB can then notify its superior NW of information related to the determined R-SgNB. This information, including at least one of the identifier and address of the SgNB that configures the routing function, can be included in the PDU session channel append request message.

[0790] The notifications made by the MgNB to the determined R-SgNB, and by the AMF to the UPF regarding information related to the R-SgNB, may appropriately employ the methods disclosed in the method by which the superior NW determines the R-SgNB.

[0791] The stopping of the routing function of the R-SgNB and the reconfiguration of the R-SgNB can also be determined by the MgNB. The same method described above can be applied appropriately.

[0792] The MgNB can notify the UE of the implementation, cessation, or reconfiguration of routing functions. Within the UE, routing functions can be configured between the upper layer and the new AS sublayer, or between the upper layer and the PDCP. The routing functions should be the same as those on the NW side.

[0793] Data routing can be configured and implemented for each UE via the MgNB. The NW side can also identify which SgNB is being used. Alternatively, the UE can configure and implement data routing, determining which SgNB to route to based on the UE's power consumption and load status.

[0794] As a routing function, it is possible to configure the mapping between QoS flows and SgNBs used by the MC. The upper-level NW device can determine the mapping correspondence. For example, the routing function is effective when configured on an upper-level NW, such as a UPF. The AMF, acting as the upper-level NW, can determine the mapping correspondence. This mapping correspondence is then notified from the AMF to the UPF. The UPF uses the notified mapping correspondence to perform the mapping between QoS flows and SgNBs.

[0795] AMF can map notifications to MgNB. MgNB can map notifications to UE. Therefore, for uplink communication, QoS flows can be mapped to MC using SgNB in ​​the UE.

[0796] RAN nodes can determine the mapping. For example, routing functionality is effective when configured on RAN-side nodes. The MgNB, acting as a RAN node, can determine the mapping. This mapping is then communicated from the MgNB to the R-SgNB. The SgNB uses the received mapping to perform QoS flow mapping between itself and the SgNB.

[0797] The MgNB can map the notifications to the UE. Therefore, for uplink communication, the mapping between QoS flows and the MC using the SgNB can also be implemented in the UE.

[0798] Therefore, an SgNB can be configured for each QoS flow. A specified SgNB can be used to communicate packet data for a given QoS flow. By appropriately configuring the SgNB based on its load and processing capacity, throughput can be improved.

[0799] This document discloses the method for setting up the DRB required by the MC in SgNB, as well as the mapping method for the new AS sublayer from SgNB.

[0800] The MgNB provides information related to DRB settings to each SgNB used by the MC. Nine examples of DRB-related information are given below.

[0801] (1) Become the DRB identifier of the MC object.

[0802] (2) Become the DRB structure of the MC object.

[0803] (3) The QoS flow identifier mapped to the DRB that becomes the MC object.

[0804] (4) QoS distribution of each QoS flow.

[0805] (5) Become the PDU session identifier of the MC object.

[0806] (6) Add a PDU session channel identifier.

[0807] (7) Identify the host device for setting up the PDU session channel.

[0808] (8) Set the address of the host device for the PDU session channel.

[0809] Combinations of (9)(1) to (8).

[0810] Each SgNB uses the DRB configuration information received from the notification to configure the DRB for MC. Each SgNB configures the mapping to the DRB configured by the new AS sublayer according to the notification information. The DRB configurations in each SgNB can be different. The DRB identifiers can also be different. MgNB can use the SgNB reconfiguration completion signaling to notify each SgNB for MC of the DRB configuration information.

[0811] The MgNB can notify each SgNB used by the MC of a PDU session channel establishment request. The information related to DRB settings mentioned above can be appropriately applied as information for the PDU session channel establishment request. The information related to DRB settings and the PDU session channel establishment request can be notified together. This notification can be performed using a single signaling message, reducing signaling load.

[0812] Each SgNB notifies the MgNB of the DRB setting response information. Eight examples of DRB setting response information are given below.

[0813] (1) The identifier of this SgNB.

[0814] (2) The address of this SgNB.

[0815] (3) DRB setting confirmation.

[0816] (4) DRB setting rejection.

[0817] (5) DRB sets the reasons for rejection.

[0818] (6) The DRB structure set by this SgNB.

[0819] (7) The DRB identifier set by this SgNB.

[0820] (8)(1) to (7) combinations.

[0821] The MgNB configures the MC (Mechanical Control Point) for the UE. As part of the MC configuration, the DRB (Diagram Reference Buffer) configuration results in each SgNB (Signal Module 1) used for the MC can be notified. The method for configuring and notifying the UE of the MC from the MgNB can appropriately apply a variation of Embodiment 6, Example 1. While MCG (Multi-Channel Group) fork bearer is disclosed in Variation 1 of Embodiment 6 as the bearer type, SCG bearer can be used in this Variation 1 of Embodiment 7.

[0822] By adopting this method, the upper-level NW can configure the MC (MC) using SCG bearers in the NG-CN. It can configure the MC for each DRB (Device Module Block). MCs can be implemented between the UE and the MgNB (MgBanner Module Block), and between the UE and the MCs using each SgNB. This can improve the throughput of DRBs with configured MCs.

[0823] Figure 32 This is a schematic diagram illustrating the data flow when MCs using SCG bearers are configured on a per-DRB basis. The mapping relationship between QoS flows and DRBs before MC configuration is set as follows: Figure 21 The relationship is shown below. The DBR for MC is set to DRB1. QoS flow 1 and QoS flow 2 are mapped to DRB1.

[0824] like Figure 32 As shown, in order to configure DRB1 as an MC using SCG bearer, MgNB adds a PDU session channel on the SgNB side of the MC. Figure 32 The following scenario is illustrated: the node with routing capabilities is configured separately from the upper-level NW. Therefore, a PDU session channel is added between the upper-level NW and the node with routing capabilities. When the routing capability is configured in the upper-level NW, a PDU session channel is added between the upper-level NW and each SgNB used by the MC.

[0825] In the added PDU session channel, QoS stream 1 and QoS stream 2, mapped to the configured MC's DRB, communicate. Packet data mapped from the upper-level NW to QoS stream 1 and QoS stream 2 communicate using the added PDU session channel.

[0826] Data is routed to the respective SgNBs used by the MC via nodes with routing capabilities. Each SgNB then uses the information from the MgNB regarding the DRB1 setting of the MC to configure the DRB for MC use. Figure 32 The following situation is shown: each SgNB has the same DRB1 setting as the MgNB. Furthermore, Figure 32 The following situation is shown: the DRB identifier is set to be the same as the DRB identifier set by MgNB.

[0827] Data mapped to QoS flow 1 and QoS flow 2 is transmitted to the new AS sublayer of each SgNB, and then mapped to DRB1 in the new AS sublayer. Thus, each SgNB using the MC can process the QoS flows mapped to the DRB1 configured with the MC.

[0828] The MgNB can notify the structure of each SgNB performing MC (Multi-access Module) and the DRB (Dual Module) structure set in each SgNB. This notification can, for example, use the method disclosed in Implementation 6 for notifying the UE of the DRB structure from the MgNB. The UE can set the DRB structure in each SgNB. The same applies to uplink data. Therefore, MC can be implemented for each DRB.

[0829] Figures 33-35 This is a diagram illustrating an example of the process for configuring an MC that uses an SGB bearer when the upper NW is NG-CN. Figures 33-35 Connect at the boundary lines BL3334 and BL3435. Figures 33-35 The case of using MgNB and two SgNBs (SgNB1, SgNB2) is shown. Figures 33-35 The process shown includes and Figure 19 and Figure 20 ,as well as Figure 29 and Figure 30 The process shown has the same steps, therefore, the same step numbers are added to the same steps, and common descriptions are omitted.

[0830] In steps ST5501 and ST5502, the MgNB notifies SgNB1 and SgNB2 of the append request from the SgNB. This append request signaling may contain the aforementioned information related to DRB settings. Information related to DRB settings includes, for example, the identifier and structure of the DRB that becomes an MC object, the identifier of the QoS flow mapped to the DRB that becomes an MC object, the QoS distribution of each QoS flow, and the PDU session identifier that becomes an MC object.

[0831] MgNB can determine the QoS distribution settings for each SgNB that sets the MC, so as to meet the QoS distribution of the MC's QoS flow.

[0832] The MgNB can notify each SgNB that it is setting the MC of the requested DRB structure. The MgNB can set the DRB structure to be the same as the original DRB structure. Alternatively, it can determine the bearer structure so that the bearer structure of the SgNB setting the MC is a bearer structure that satisfies the QoS distribution of the QoS flows performing the MC.

[0833] SgNB1 and SgNB2, having received information related to DRB settings from the MgNB, set the DRB for the QoS flows mapped to MC objects. In steps ST5503 and ST5504, SgNB1 and SgNB2 notify the MgNB of an append request response to the append request. The append request response signaling may include the aforementioned DRB setting response information. The append request response may be, for example, a DRB setting confirmation, and the DRB setting response information may include, for example, the DRB identifier and structure set by this SgNB, the identifier and address of this SgNB, etc. Furthermore, the AS settings set by this SgNB may be notified.

[0834] In step ST5505, the MgNB that receives the SgNB append request response signaling from each SgNB used for the MC notifies the upper-level NW of the PDU session channel append request to configure the MC using the SCG bearer. The aforementioned PDU session channel append information can be included in the PDU session channel append request signaling. This PDU session channel append information includes, for example, the PDU session identifier that becomes the MC object, the PDU session channel identifier that becomes the MC object, the QoS flow identifier that becomes the MC object, the SgNB identifier and address used by the MC, etc.

[0835] In step ST5506, the AMF / SMF notifies the UPF of a PDU session channel append request. Similarly, the PDU session channel append information can be included in the PDU session channel append request signaling.

[0836] In step ST5506, the UPF that has been notified of the PDU session channel append request and PDU session channel append information appends and sets up a PDU session channel with each SgNB used for MC.

[0837] In step ST4302, the MgNB notifies the UE of the MC settings. As MC settings, the MC can be notified of the SCG structure of each SgNB used for the MC, and the DRB structure set by each SgNB. As signaling, RRCConnectionReconfiguration can be used for setting up RRC connections. Furthermore, the bearer type can be notified as an SCG bearer.

[0838] In step ST4302, the UE that receives the SCG and DRB structures of SgNB1 and SgNB2 performs MC configuration for MeNB, SgNB1, and SgNB2 according to the settings. In step ST4303, the UE notifies the MgNB that the RRC connection reconfiguration is complete, including the completion of MC configuration.

[0839] In step ST4207, the MgNB, having identified that the UE has completed the MC configuration, notifies SgNB1 that the additional configuration of the SCG for each SgNB is complete, and in step ST4219, notifies SgNB2 that the additional configuration of the SCG for each SgNB is complete. SgNB1 and SgNB2 recognize that the connection configuration for the MC with the UE is complete.

[0840] The MgNB can use the signaling indicating completion of the SCG additional configuration in steps ST4207 and ST4219 to notify SgNB1 and SgNB2 of the PDU session channel establishment request. The information related to the DRB configuration mentioned above can be included in the signaling indicating completion of the SCG additional configuration as information for the PDU session channel establishment request.

[0841] Information related to DRB settings includes, for example, the DRB identifier that becomes an MC object, the QoS flow identifier mapped to the DRB that becomes an MC object, the PDU session identifier that becomes an MC object, the PDU session channel identifier that is added, and the identifier and address of the host device that establishes the PDU session channel.

[0842] Therefore, a PDU session channel is added between the AMF / SMF and each SgNB used in the MC. This enables data communication between the SgNB used in the MC that uses SCG bearers and the host NW.

[0843] In steps ST4028 and ST4220, the UE performs RA processing on SgNB1 and SgNB2 to establish synchronization. Then, in steps ST5201 to ST5203, the SN state transmission and data transmission from MgNB to SgNB1 are performed. Regarding data transmission, the method disclosed in Implementation Method 7 can be appropriately applied.

[0844] In step ST5508, the MgNB notifies the AMF / SMF of a PDU session channel switching request. The MgNB requests that the QoS flows contained in the DRB, which is now the MC object, be changed from the PDU session channel before the MC was set to the PDU session channel added between the SgNBs used for the MC. Information for the PDU session channel switching can be included in the PDU session channel switching request signaling.

[0845] Here are eight examples of information for PDU session channel switching.

[0846] (1) The QoS flow identifier mapped to the DRB that becomes the MC object.

[0847] (2) Become the PDU session identifier of the MC object.

[0848] (3) Add a PDU session channel identifier.

[0849] (4) Identify the host device for setting up the PDU session channel.

[0850] (5) Set the address of the host device for the PDU session channel.

[0851] (6) Identification of SgNB used for MC.

[0852] (7) The address of SgNB used for MC.

[0853] (8)(1) to (7) combinations.

[0854] Similar to step ST5508, in step ST5509, the AMF / SMF notifies the UPF of a PDU session channel switching request. Upon receiving the PDU session channel switching request, the UPF sends an end-marked packet in step ST5206 as the final packet data to the MgNB, and uses the information notified in the PDU session channel switching request to switch to the PDU channel appended to the SgNB used for the MC. In step ST5207, the MgNB transmits the end-marked packet to SgNB1. Thus, SgNB1 recognizes that the data from the MgNB has ended.

[0855] In step ST5509, the AMF / SMF that notified the UPF of the PDU session channel switching request responded to the MgNB's notification of the PDU session channel switching request. Thus, the MgNB can recognize that it has switched to the PDU session channel added between SgNB1 and SgNB2 in the MC.

[0856] In step ST5509, the UPF, having received the MC path switching setting information, sends an end-marker packet in step ST5206 as the final packet data to the MgNB and initiates the path switching. In step ST5207, the MgNB transmits the end-marker to SgNB1. Thus, SgNB1 recognizes that the data from the MgNB has ended.

[0857] In step ST5210, the packet data is routed between each SgNB used by the MC by setting the routing function in the UPF. In steps ST5211 to ST5214, data communication is performed between SgNB1, SgNB2 and the UPF.

[0858] Therefore, when the upper-level NW is NG-CN, MC using SCG bearers can be performed. The MgNB can configure the UE to use SCG bearers for MC. The UE can connect to multiple SgNBs used for MC to perform MC.

[0859] Regarding the data forking method in the uplink of MC, the method disclosed in Implementation 6 can be appropriately applied. This can be applied to SgNB used in MC.

[0860] Regarding the method for initiating the transmission of uplink data from the UE to the base station, the method disclosed in Implementation Method 6 can be appropriately applied. This can be applied to the MgNB and the SgNB used for the MC.

[0861] A method is disclosed for returning the MCG bearer from the settings of an MC that uses an SCG bearer. When a PDU session channel is configured between the MgNB and the upper-level NW for a PDU session that becomes an MC object, the MgNB is configured to remove the PDU session channel configured on each SgNB, and the PDU session channel configured between the MgNB and the upper-level NW is used for the QoS flow contained in the MC object, i.e., the DRB.

[0862] If no PDU session channel is configured between the MgNB and the upper-level NW for the PDU session to be used as the MC object, the MgNB can configure a PDU session channel between the MgNB and the upper-level NW. The MgNB is configured to remove the PDU session channel configured on each SgNB, and the PDU session channel configured between the MgNB and the upper-level NW is used for the QoS flow contained in the MC object, i.e., the DRB.

[0863] Furthermore, the MgNB can remove the MC settings used between each SgNB and the UE. The above methods can be applied appropriately.

[0864] Other configuration methods for MCs using SCG bearers are disclosed. MCs are configured for each QoS process. For one or more QoS flows within a QoS flow mapped to a DRB, a new AS sublayer performs MC configuration using an SCG bearer.

[0865] In addition to the above-mentioned problems, the following problems will also arise when the upper-level NW uses the MC carried by SCG in the NG-CN setting per QoS flow.

[0866] When multiple QoS flows are mapped to a single DRB by the MgNB, and the MC is configured by separating each QoS flow into multiple QoS flows, the mapped QoS flows may still remain in the DRB after the MC is configured. In this case, data is also processed via PDCP and an SN is appended after the MC is configured.

[0867] When transferring the connection with the UE from the MgNB to the SgNB using the MC carried by the SCG, it is necessary to transmit the data during processing in the MgNB to the SgNB. Previously, this was achieved by transmitting the SN status, which was then used to set the PDCP SN in the SgNB. This allows the UE to perform SN-based PDCP reordering.

[0868] However, as mentioned above, when multiple QoS flows are mapped to a DRB with a set MC, the following situation arises: not only is data from QoS flows with a set MC transmitted to the SgNB, but data from QoS flows without a set MC is also transmitted to the SgNB. In this case, data from QoS flows without a set MC is also processed by the SgNB's PDCP, thus causing the following problem: data from QoS flows with a set MC cannot be properly reordered. The same applies to the uplink.

[0869] As a solution to the above problems, each QoS stream is processed during transmission. Data transmitted from the MgNB to the SgNB can be limited to QoS streams with a set MC. The MgNB uses the QoS stream identifier attached to the data to determine whether to transmit the data to the SgNB if it is a QoS stream with a set MC, and not to transmit it if it is not a QoS stream with a set MC.

[0870] QoS stream data transmitted to the SgNB is processed by the SgNB. QoS stream data not transmitted to the SgNB is processed by the MgNB. Thus, by processing each QoS stream during transmission, data within the SgNB can be processed correctly.

[0871] As another method to solve the above problem, an additional DRB is set for the QoS flow performing MC, and the QoS flow performing MC is mapped to the additional set DRB. By setting the additional set DRB to MC, MC can be set for the QoS flow mapped to that DRB.

[0872] Therefore, after MC is configured, QoS flows mapped to the additionally configured DRB will not remain. Consequently, the data of the QoS flows mapped to the additionally configured DRB that are used for MC is transmitted to the SgNB. The SgNB's PDCP processes the data of the QoS flows used for MC, thus enabling proper reordering. The same applies to the uplink.

[0873] The method of adding a DRB for the QoS flow of MC and mapping the QoS flow of MC to the added DRB can be appropriately applied to the method of adding a DRB for the QoS flow of MC disclosed in Variation 1 of Embodiment 6.

[0874] Figure 36This is a schematic diagram illustrating the data flow when the MC using the SCG bearer is configured on a per-QoS basis. The mapping relationship between the QoS flow and the DRB before MC configuration is set as follows: Figure 21 The relationship is shown below. The DBR for MC is set to DRB1. QoS flow 1 and QoS flow 2 are mapped to DRB1.

[0875] like Figure 36 As shown, in order to set QoS flow 1 in DRB1 to the MC using SCG bearer, MgNB adds a PDU session channel on the SgNB side of the MC. Figure 36 The following scenario is illustrated: the node with routing capabilities is configured separately from the upper-level NW. Therefore, a PDU session channel is added between the upper-level NW and the node with routing capabilities. When the routing capability is configured in the upper-level NW, a PDU session channel is added between the upper-level NW and each SgNB used by the MC.

[0876] In the newly configured PDU session channel, communication for QoS stream 1 of the configured MC is performed. Packet data mapped from the upper-level NW to QoS stream 1 is communicated using the newly configured PDU session channel.

[0877] Data is routed to each SgNB used by the MC via nodes with routing capabilities. Each SgNB uses the DRB1 information (notified by the MgNB that configures the MC) to configure the DRB for MC use. Each SgNB can also use the QoS distribution information of QoS flow 1 (notified by the MgNB that configures the MC) to configure the DRB for MC use.

[0878] Figure 36 The following situation is illustrated: each SgNB has set a different DRB1 setting than the MgNB. Furthermore, Figure 36 The following situation is shown: the DRB identifier is set to a different DRB identifier (DRBY1) than the DRB identifier set by MgNB.

[0879] Data mapped to QoS flow 1 is transmitted to the new AS sublayer of each SgNB and mapped to DRBY1 in the new AS sublayer. Thus, each SgNB using the MC can process QoS flow 1 configured with the MC.

[0880] On the other hand, in DBR1, QoS flow 2 does not have a MC set, and QoS flow 2 communicates on the MgNB side. For QoS flow 2, the MgNB maintains the DRB on the MgNB side in DRB1. The MgNB can reconfigure DRB1. For example, after the MC is set, the DRB structure suitable for QoS flow 2 can be reconfigured.

[0881] Figure 36 The following situation is shown: Perform the same settings as DRB1 set by MgNB. Furthermore, Figure 36 The following situation is shown: the DRB identifier is set to the same DRB identifier (DRB1) as the DRB identifier set by MgNB.

[0882] Communication for QoS Stream 2 utilizes the PDU session channel established between the upper-level NW and MgNB before MC configuration. Data mapped from the upper-level NW to QoS Stream 2 is transmitted to the MgNB's new AS sublayer and mapped to DRB1 within it. This allows MgNB to process QoS Stream 2 even without MC configuration.

[0883] The MgNB can notify the UE of the reconfigured DRB structure. Furthermore, the MgNB can notify the SCNBs that configure the MC, as well as the DRB structure configured in each SCNB. This notification can, for example, employ the method disclosed in Implementation 6 for notifying the UE of the DRB structure from the MgNB. The UE can reconfigure the DRB structure configured on the MgNB side, and also configure the DRB structure configured in each SCNB. The same applies to uplink data. Thus, MC can be implemented for each QoS flow.

[0884] The process of setting the MC for each QoS flow using SCG bearer can be applied. Figure 26 and Figure 27 To additionally configure a DRB for QoS flows performing MC, steps ST4902 to ST4913 can be performed. An additional DRB for QoS flows performing MC is configured, and the QoS flows performing MC are mapped to the additional configured DRB. By configuring the additional configured DRB as an MC, MC can be configured for the QoS flows mapped to that DRB.

[0885] Therefore, after MC is configured, QoS flows mapped to the additionally configured DRB will not remain. Consequently, the data of the QoS flows mapped to the additionally configured DRB that are used for MC is transmitted to the SgNB. The SgNB's PDCP processes the data of the QoS flows used for MC, thus enabling proper reordering. The same applies to the uplink.

[0886] In step ST4914, the MgNB begins to add DRB settings using the SCG bearer for MC QoS flow configuration. In step ST4915, the MgNB, SgNB1 and SgNB2 used for MC, AMF / SMF, UPF, and UE perform MC configuration processing using the SCG bearer among themselves. This MC configuration processing can be applied... Figures 33-35 .

[0887] Regarding the data forking method in the uplink of the MC, the method disclosed in Implementation Method 6 can be appropriately applied. This can be applied to the SgNB that sets the MC for each QoS flow.

[0888] Regarding the method for initiating the transmission of uplink data from the UE to the base station, the method disclosed in Implementation Method 6 can be appropriately applied. This can be applied to the MgNB and the SgNB, which sets the MC for each QoS flow. The SR and BSR for each QoS process can be set and notified from the UE to the base station.

[0889] Therefore, when the upper-level NW is NG-CN, MC using SCG bearers can be performed. The MgNB can configure the UE to use SCG bearers for MC. The UE can connect to multiple SgNBs used for MC to perform MC.

[0890] Furthermore, the MgNB can implement MC (Controlled Mechanism) for each QoS flow using the SCG bearer for the UE. Since MC can be implemented for each QoS flow, it allows for finer QoS precision control compared to MC per bearer.

[0891] A base station for an MC that is not connected to an upper-level NW can use an eNB as an LTE base station. Both eNBs and gNBs can be used. The method disclosed in this variation 1 of embodiment 7 can be appropriately applied. In this variation 1, the base station for an MC that is not connected to an upper-level NW does not use the new AS sublayer, therefore an eNB can be used.

[0892] By employing the method disclosed in this variant 1 of embodiment 7, even when the upper-level NW is NG-CN, it is possible to configure a UE to connect to multiple secondary base stations. This increases the communication throughput provided to the UE. Furthermore, by connecting to multiple base stations, reliability is improved. Additionally, since an MC using SCG bearers can be configured, communication without MgNB can be provided. Therefore, the communication throughput provided to the UE is increased.

[0893] Implementation Method 8.

[0894] In Implementation 7, an MC using SCG bearers is disclosed. In an MC using SCG bearers, when routing functionality is configured for the upper-level NW, communication occurs between the upper-level NW and each SgNB used for the MC. Since such communication is not allowed, it is necessary to notify the upper-level NW of the settings of each SgNB, resulting in a problem where the MC configuration becomes complex and the signaling volume between the upper-level NW and the base station increases.

[0895] Furthermore, the information required for routing needs to be sent to nodes with routing capabilities. This will also lead to an increase in signaling traffic between the upper-level NW and the base station.

[0896] This embodiment 8 discloses a method for solving the above-mentioned problems. An SGC fork bearer is set up to branch to other SgNBs.

[0897] In existing SCG forked bearers, the SgNB is connected to the upper-level NW device, and this SgNB forks data from the upper-level NW to its own SgNB and MeNB. The same applies to uplink communication. That is, it becomes a DC using both a MeNB and an SgNB.

[0898] In the SCG fork bearer disclosed in Embodiment 8, the SgNB is connected to the upper-level NW device, and this SgNB forks data from the upper-level NW to itself and other SgNBs. The MeNB is used for C-Plane communication, etc., which means it becomes the MC using the SgNB and other SgNBs connected to the MeNB and the upper-level NW device. The same applies to uplink communication. There can be one or more other SgNBs. Sometimes the SgNB connected to the upper-level NW device is called a P-SgNB.

[0899] Figure 37 This is a diagram illustrating the architecture of the MC. It shows the following configuration: the upper-level NW is the EPC, the primary base station is the base station (eNB) in LTE, and the secondary base station is the base station (gNB) in NR. Figure 37 This diagram illustrates the architecture on the base station side, but the architecture on the UE side is the same except for the upper-level NW. In one UE, the RLC, MAC, and PHY for PDCP and MgNB are configured, and the RLC, MAC, and PHY for each SgNB configured as MC are also configured.

[0900] Figure 37This illustrates a scenario using an SCG fork bearer. The upper-level NW is connected to an SgNB (P-SgNB), and other SgNBs used by the MC are connected to the P-SgNB. Downlink data is transmitted from the upper-level NW to the P-SgNB. Data is then transmitted to the PDCP without passing through the P-SgNB's new AS sublayer. Data from the upper-level NW can be input to the P-SgNB's new AS sublayer, but this data passes through unprocessed.

[0901] Downlink data is processed by the P-SgNB's PDCP. Even if there are multiple other SgNBs, a consecutive sequence number (SN) is used in the PDCP and appended to each data item. Data with the appended SN is branched to the local P-SgNB and the other SgNBs. The branched data is sent to the RLC of the local P-SgNB and the other SgNBs, where it is processed by the RLC, MAC, and PHY of the P-SgNB and the other SgNBs, and then sent to the UE.

[0902] Data received by the UE from the P-SgNB and other SgNBs is processed by the PHY, MAC, and RLC of the P-SgNB and other SgNBs respectively, and then transmitted to the PDCP. In the PDCP, the data is reordered based on the SN attached to the data transmitted from the P-SgNB and other SgNBs and then transmitted to the upper layer.

[0903] For uplink data, the UE utilizes PDCP to process data from the upper layer. Similar to the downlink, even if there are multiple other SgNBs, a consecutive sequence number (SN) is used in PDCP and assigned to each data item. Data with the SN appended is branched for transmission via RLC used by the P-SgNB and other SgNBs. The transmitted data is processed by the RLC, MAC, and PHY of the P-SgNB and other SgNBs, and then sent to the P-SgNB and other SgNBs.

[0904] Data received from the UE by the P-SgNB and other SgNBs is processed by the PHY, MAC, and RLC systems used by the P-SgNB and other SgNBs, and then transmitted to the P-SgNB's PDCP. In the P-SgNB's PDCP, the data is reordered based on the SN assigned to it and transmitted to the higher-level NW.

[0905] Routing functions for branch bearers can be configured on the gNB. Routing functions to the SgNB used by the MC can be configured on the gNB. As an MC using an SCG branch bearer, the routing functions configured on the P-SgNB can be used. Regarding the routing functions, the method disclosed in Implementation Method 6 can be appropriately applied.

[0906] A method for configuring a MeNB using SCG forked bearers has been disclosed. The MeNB determines all SgNBs used in the MC. The MeNB determines the P-SgNBs and other SgNBs used in the MC. The MeNB configures the bearer structure for each SgNB used in the MC and sends a request to each SgNB. The MeNB notifies each SgNB of the bearer structure configuration request. As the bearer structure, the type of bearer can be notified. It can be notified if it is an SCG forked bearer. It can be notified if it is an SCG forked bearer using P-SgNBs and other SgNBs.

[0907] As a configuration method for a MeNB using SCG forked bearers, an additional method for configuring SgNBs is disclosed. First, the MeNB configures the SgNB (P-SgNB) connected to the upper-level NW as an SgNB. Next, the P-SgNB used in the MeNB and other SgNBs are configured with SCG forked bearers. The initial SCG bearer configuration for the P-SgNB can be applied using the configuration method for a DC using SCG bearers.

[0908] A method for configuring SCG fork bearers for P-SgNBs and other SgNBs used in a MeNB is disclosed. The MeNB requests other SgNBs to add SgNBs for SCG fork bearers. The MeNB notifies the other SgNBs by including information related to the addition of the SgNBs for SCG fork bearers in the request. Seven examples of this information notified from the MeNB to the other SgNBs are disclosed below.

[0909] (1) indicates the information set for SCG fork carrying.

[0910] (2) SCG bifurcation bearing structure.

[0911] (3) Information related to P-SgNB.

[0912] (4) Information related to setting the DRB of the MC.

[0913] (5) The bearer structure set for each SgNB. QoS distribution, etc.

[0914] (6) Information related to the UE performing MC.

[0915] (7)(1) to (6) combinations.

[0916] As the SCG fork bearer structure described in (2) above, it includes information such as whether the notified SgNB is another SgNB and whether it is forked from the P-SgNB. As the information related to the P-SgNB described in (3) above, it includes the P-SgNB's identifier, P-SgNB's address, etc. Information indicating connection to the P-SgNB can be included in this information. Alternatively, it can indicate an instruction to connect to the P-SgNB based on this requ...

Claims

1. A communication system comprising: User equipment; and The communication system comprises a distribution unit (DU) for wireless communication with the user equipment and a central unit (CU) connected to the distribution unit, characterized in that... The base station containing the CU and the DU supports packet replication. The CU will notify the DU of information related to the commencement of the group replication. Based on the information, the DU will notify the user device of the start of the packet replication via MAC signaling.

2. The communication system as described in claim 1, characterized in that, The DU will notify the CU of information related to cell load and scheduling status.

3. The communication system as described in claim 1, characterized in that, The CU will notify the DU of information related to whether or not to perform the grouped replication.

4. A user equipment, which is a user equipment in a communication system, the communication system comprising: User equipment; and A base station includes a distribution unit (DU) for wireless communication with the user equipment and a central unit (CU) connected to the distribution unit, supports packet replication, and the CU notifies the DU of information related to the initiation of packet replication. The user equipment is characterized in that... The user equipment is notified to begin packet replication via MAC signaling sent by the DU based on the information.

5. A base station, which is a base station in a communication system, the communication system comprising: User equipment; and A base station comprising a distribution unit (DU) for wireless communication with the user equipment and a central unit (CU) connected to the distribution unit, characterized in that... The base station containing the CU and the DU supports packet replication. The CU will notify the DU of information related to the commencement of the group replication. Based on the information, the DU will notify the user device of the start of the packet replication via MAC signaling.

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