Communication device, master node, and communication control method

Abstract

A UE (100) is connected to a master node (200-1) associated with a MCG and to a secondary node (200-2) associated with a SCG in a dual connectivity manner. The UE (100) includes a control section (130) including a PDCP entity (131) corresponding to a split bearer, a master RLC entity (132) corresponding to the aforementioned PDCP entity, and a secondary RLC entity (134) corresponding to the aforementioned PDCP entity, and a reception section (120) that receives, in a case where the aforementioned SCG is deactivated, from the aforementioned master node (200-1), an RRC message including information that configures an ID of a cell group corresponding to the aforementioned master RLC entity as an ID of the aforementioned MCG. The aforementioned PDCP entity (131) outputs a PDCP PDU to the aforementioned master RLC entity (132) in a case where a total of a PDCP data amount and a reserved initial transmission RLC data amount is less than a threshold value.

Description

[0001] Cross-references of related applications

[0002] This application claims priority based on Japanese Patent Application No. 2021-107712, filed on June 29, 2021, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to communication equipment, master nodes, and communication control methods used in mobile communication systems. Background Technology

[0004] Dual Connectivity (DC) was introduced in 3GPP (Third Generation Partnership Project), a standardization project for mobile communication systems (registered trademark, hereinafter the same).

[0005] In dual connectivity mode, only one of the multiple base stations (hereinafter sometimes referred to as the "primary base station" or "primary node") establishes an RRC (Radio Resource Control) connection with the communication equipment (UE). On the other hand, the other base stations besides the primary base station (hereinafter sometimes referred to as "secondary base stations" or "secondary nodes") do not establish RRC connections with the communication equipment, but instead provide additional radio resources to the communication equipment.

[0006] In dual-connectivity mode, the communication equipment uses both the radio resources of the master node and the radio resources of the slave node to transmit and receive user data. This allows the communication equipment to increase its throughput.

[0007] In addition, MR-DC (Multi-Radio DC) was introduced in 3GPP. MR-DC is a dual connectivity method between LTE (Long Term Evolution) nodes and NR (New Radio) nodes, or between NR nodes.

[0008] On the other hand, compared to wireless communication with a single base station, communication devices that use dual connectivity consume more power.

[0009] Therefore, within 3GPP, techniques for deactivating secondary cell groups (SCGs) managed by secondary nodes based on conditions are being explored.

[0010] Regarding the deactivation of SCGs, as a protocol matter in 3GPP, there are, for example, the following: Only the master node can generate RRC messages related to the activation or deactivation of the SCG, and / or communication devices can instruct the master node that they wish to deactivate the SCG, etc.

[0011] In addition, as one of the issues currently proposed in 3GPP, there is the following: During the period when the SCG is deactivated, the communication equipment, having uplink data transmitted via a separate bearer, transmits uplink data through the primary cell group (MCG) tributary independently of the primary path.

[0012] Existing technical documents

[0013] Non-patent literature

[0014] Non-patent literature 1: 3GPP TS 37.340V16.5.0

[0015] Non-patent document 2: 3GPP announcement: R2-2104315

[0016] Non-patent document 3: 3GPP announcement: R2-2103977

[0017] Non-patent literature 4: 3GPP announcement: R2-2103979 Summary of the Invention

[0018] Regarding the aforementioned issues, no consensus has been reached within 3GPP on how communication equipment should send uplink data to the MCG side.

[0019] Therefore, when the communication equipment is configured with a separate bearer capable of sending uplink data to both the MCG and SCG, the communication equipment may sometimes be unable to properly send uplink data to the MCG side when the SCG is deactivated.

[0020] Therefore, the purpose of this disclosure is to provide a communication device, a master node, and a communication control method capable of appropriately sending data to the MCG side.

[0021] The first method involves a communication device that uses a dual-connection method to connect to a master node associated with the MCG and a slave node associated with the SCG. The communication device includes: a control unit, comprising a PDCP (Packet Data Convergence Protocol) corresponding to the separate bearer, a master RLC (Radio Link Control) entity corresponding to the aforementioned PDCP entity, and a slave RLC entity corresponding to the aforementioned PDCP entity; and a receiving unit that, when the aforementioned SCG is deactivated, receives an RRC message from the aforementioned master node containing information including: configuring the ID of the cell group corresponding to the aforementioned master RLC entity as the ID of the aforementioned MCG. When the total amount of PDCP data and RLC data reserved for initial transmission is less than a threshold, the aforementioned PDCP entity outputs a PDCP PDU to the aforementioned master RLC entity.

[0022] The second method involves a master node connected to a secondary node associated with an SCG via a dual-connectivity communication device. The aforementioned communication device includes a PDCP entity corresponding to the separate bearer, a primary RLC entity corresponding to the aforementioned PDCP entity, and a secondary RLC entity corresponding to the aforementioned PDCP entity. The aforementioned master node includes a transmitting unit that, when the aforementioned SCG is deactivated, sends an RRC message to the aforementioned communication device containing the following information: configuring the ID of the cell group corresponding to the aforementioned primary RLC entity to the ID of the MCG associated with the aforementioned master node.

[0023] The third approach involves a communication control method within a communication device. The aforementioned communication device utilizes a dual-connection method to connect to a primary node associated with the MCG and a secondary node associated with the SCG. The communication device includes a PDCP entity, a primary RLC entity corresponding to the PDCP entity, and a secondary RLC entity corresponding to the PDCP entity. The communication control method includes the following steps: when the SCG is deactivated, receiving an RRC message from the primary node containing information including: configuring the ID of the cell group corresponding to the primary RLC entity as the ID of the MCG; and when the total amount of PDCP data and RLC data reserved for initial transmission is less than a threshold, the PDCP entity outputs a PDCP PDU to the primary RLC entity. Attached Figure Description

[0024] The foregoing and other objects, features, and advantages of this disclosure will become clearer from the following detailed description, taken in conjunction with the accompanying drawings. The drawings are as follows:

[0025] Figure 1 This is a diagram illustrating an example configuration of a mobile communication system according to an embodiment of this disclosure.

[0026] Figure 2 This is a diagram illustrating an example of the configuration of a protocol stack involved in an embodiment of this disclosure.

[0027] Figure 3 This is a diagram illustrating an example of the configuration of a protocol stack involved in an embodiment of this disclosure.

[0028] Figure 4 This is a diagram illustrating an example configuration of a UE according to an embodiment of this disclosure.

[0029] Figure 5 This is a diagram illustrating an example of the configuration of a base station according to an embodiment of this disclosure.

[0030] Figure 6 This is a diagram illustrating an example of a separate carrier involved in an embodiment of this disclosure.

[0031] Figure 7 This is a diagram illustrating examples of actions involved in embodiments of this disclosure.

[0032] Figure 8 This is a diagram illustrating a specification example of an implementation of the present disclosure.

[0033] Figure 9 This is a diagram illustrating a specification example of an implementation of the present disclosure.

[0034] Figure 10 This is a diagram illustrating an example of a separate carrier involved in an embodiment of this disclosure.

[0035] Figure 11 This is a diagram illustrating examples of actions involved in embodiments of this disclosure.

[0036] Figure 12 This is a diagram illustrating an example of information included in a message related to an embodiment of this disclosure.

[0037] Figure 13 This is a diagram illustrating an example of information included in a message related to an embodiment of this disclosure.

[0038] Figure 14 This is a diagram illustrating an example of information included in a message related to an embodiment of this disclosure.

[0039] Figure 15 This is a diagram illustrating an example of information included in a message related to an embodiment of this disclosure. Detailed Implementation

[0040] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Furthermore, in this specification and the accompanying drawings, elements that can be described in the same way are designated by the same or similar reference numerals, and repeated descriptions are omitted.

[0041] [First Implementation Method]

[0042] (1.1) Example of a mobile communication system

[0043] Figure 1 This diagram illustrates an example configuration of a mobile communication system 1 according to an embodiment of this disclosure. The mobile communication system 1 is, for example, a 3GPP 5G (5th Generation) system. The mobile communication system 1 can coexist with both LTE and 5G systems. Furthermore, the mobile communication system 1 can coexist with 5G systems and other generations (e.g., 6th Generation). The mobile communication system 1 can also be a system conforming to standards other than 3GPP.

[0044] like Figure 1 As shown, the mobile communication system 1 may be referred to as a radio access network (hereinafter, sometimes referred to as "NG-RAN" (Next Generation Radio Access Network)) 20, a core network (hereinafter, sometimes referred to as "5GC" (5G Core Network)) 30, and user equipment (hereinafter, sometimes referred to as "UE" (User Equipment)) 100.

[0045] NG-RAN 20 includes base stations (gNBs) 200 that serve as nodes in the radio access network.

[0046] Base station 200 is a wireless communication device that communicates wirelessly with UE 100. Base station 200 manages one or more cells. Base station 200 communicates wirelessly with UE 100, which has established an RRC connection, within its own cell. Base station 200 has radio resource management functions, user data (hereinafter, sometimes referred to as "data") routing functions, and measurement and control functions for mobility control and scheduling, etc.

[0047] Furthermore, "cell" is used as a term to represent the smallest unit of a wireless communication area. "Cell" can also be used as a term to represent a function for wireless communication with UE 100, or as a term to represent resources. A cell belongs to one carrier frequency. Figure 1 In the middle, base station 200-1 manages cell C1, and base station 200-2 manages cell C2.

[0048] The 5GC 30 includes a core network device 300.

[0049] The core network apparatus 300 includes means corresponding to the control plane. In this case, the core network apparatus 300 can communicate with the UE 100 using NAS (Non-Access Stratum) signaling to perform various mobility controls on the UE 100. The core network apparatus 300 can be an AMF (Access Management Function) or an MME (Mobility Management Entity).

[0050] Additionally, the core network device 300 includes devices corresponding to the user plane. In this case, the core network device 300 performs forwarding control of the data of the UE 100. The core network device 300 can be a UPF (User Plane Function) or an S-GW (Serving Gateway).

[0051] like Figure 1 As shown, each base station 200-1 and 200-2 is interconnected with 5GC 30 via an interface called the NG interface. Additionally, each base station 200-1 and 200-2 is interconnected with each other via an interface called the Xn interface.

[0052] UE 100 can be, for example, a mobile wireless communication device such as a smartphone, tablet computer, personal computer, communication module, or communication card. UE 100 can be a vehicle (e.g., a car, tram, etc.) or a device installed in a vehicle. Alternatively, UE 100 can be a transport vehicle (e.g., a ship, airplane, etc.) or a device installed in a transport vehicle. UE 100 can also be a sensor or a device installed in a sensor. Furthermore, UE 100 can also be used as a mobile station, mobile terminal, mobile device, mobile unit, subscriber station, subscriber terminal, subscriber device, remote station, remote terminal, remote device, or remote unit, among other names.

[0053] In addition, Figure 1 The example shown illustrates a UE 100 located in both cell C1 managed by base station 200-1 and cell C2 managed by base station 200-2.

[0054] (1.2) Example of Protocol Stack Construction

[0055] Figure 2 This is a diagram illustrating an example of the configuration of a protocol stack involved in an embodiment of this disclosure. Figure 2 This illustrates an example of the configuration of a protocol stack related to the control plane.

[0056] like Figure 2As shown, the protocols related to the control plane include the PHY (Physical) layer, MAC (Media Access Control) layer, RLC (Radio Link Control) layer, PDCP (Packet Data Convergence Protocol) layer, and RRC layer in UE 100 and base station 200. The NAS layer is also included in UE 100 and core network device 300.

[0057] The PHY layer performs encoding / decoding, modulation / demodulation, antenna mapping / demapping, and resource mapping / demapping. Data and control information are transmitted between the PHY layer of UE100 and the PHY layer of base station 200 via physical channels.

[0058] The MAC layer performs data priority control, retransmission processing using Hybrid Automatic Repeat Request (HARQ), and random access procedures. Data and control information are transmitted between the MAC layer of UE 100 and the MAC layer of base station 200 via a transport channel. The MAC layer of base station 200 includes a scheduler. The scheduler determines the uplink and downlink transmission formats (transmission block size, modulation and coding schemes) and allocates resource blocks.

[0059] The RLC layer utilizes the functions of the MAC layer and PHY layer to transmit data to the RLC layer on the receiving side. Data and control information are transmitted between the RLC layer of UE 100 and the RLC layer of base station 200 via a logical channel.

[0060] The PDCP layer performs header compression / decompression and encryption / decryption. Data and control information are transmitted between the PDCP layer of UE 100 and the PDCP layer of base station 200 via radio bearer.

[0061] The RRC layer controls logical channels, transport channels, and physical channels in response to the establishment, re-establishment, and release of radio bearers. RRC signaling for various configurations is transmitted between the RRC layer of UE 100 and the RRC layer of base station 200. When an RRC connection with base station 200 exists, UE 100 is in an RRC connected state. When no RRC connection with base station 200 exists, UE 100 is in an RRC idle state.

[0062] The NAS layer performs session management and mobility management, among other things. NAS signaling is transmitted between the NAS layer of UE 100 and the NAS layer of core network device 300.

[0063] Figure 3 This is a diagram illustrating an example of the configuration of a protocol stack involved in an embodiment of this disclosure. Figure 3 This illustrates an example of the protocol stack configuration related to the user plane.

[0064] like Figure 3 As shown, the protocols related to the user plane include the PHY layer, MAC layer, RLC layer, PDCP layer and SDAP (Service Data Protocol) layer in UE 100 and base station 200.

[0065] The SDAP layer maps QoS (Quality of Service) flows to data radio bearers and assigns QoS flow IDs (identifications) to both uplink (UL) and downlink (DL) connections. Furthermore, in LTE systems, the SDAP layer may not be present.

[0066] (1.3) Dual connection method

[0067] UE 100 can utilize resources provided by two different nodes connected via a non-ideal backhaul. In this case, one node becomes the master node (MN) managing the primary cell group (hereinafter, sometimes referred to as "MCG"). The other node becomes the secondary node (SN) managing the secondary cell group (hereinafter, sometimes referred to as "SCG"). The master and secondary nodes are connected via a network interface (Xn interface). At least the master node is connected to the core network.

[0068] The master node provides a single control plane for the core network (e.g., 5GC 30). The master node is sometimes referred to as the master eNB (evolved Node B), master ng-eNB (new generation-eNB), or master gNB.

[0069] The secondary node provides additional radio resources to UE 100 without utilizing the control plane's connection to the core network. The secondary node is sometimes referred to as en-gNB, secondary ng-eNB, or secondary gNB.

[0070] Here, the primary node and the secondary node are logical entities. In this embodiment, it is assumed that the primary node corresponds to base station 200-1 and the secondary node corresponds to base station 200-2, as will be explained below.

[0071] MCG is a group of serving cells associated with the primary node. An MCG includes the primary cell (Sp cell or P cell) and optionally one or more secondary cells (S cells).

[0072] SCG is a group of serving cells associated with secondary nodes. An SCG includes a primary cell (Sp cell or PS cell) and optionally one or more secondary cells (S cells). The Sp cell is the primary cell in the MCG and also the primary cell in the SCG.

[0073] UE 100 can connect to the master node managing the MCG and the slave node managing the SCG. In this case, UE 100 connects to both nodes and performs wireless communication.

[0074] In addition, the dual-connectivity configuration is performed by the master node sending a pre-defined message (e.g., an SNAddition Request message) to the slave node, and further, the master node sends an RRC message (e.g., an RRCReconfiguration message) to the UE 100.

[0075] Hereinafter, base station 200-1 is sometimes referred to as master node 200-1 or master base station 200-1. Additionally, hereafter, base station 200-2 is sometimes referred to as auxiliary node 200-2 or auxiliary base station 200-2.

[0076] (1.4) Deactivation of SCG

[0077] Next, we will explain how to deactivate SCG.

[0078] In 3GPP, the deactivation of SCGs is being explored to suppress the power consumption of UE 100. When an SCG is deactivated, UE 100 deactivates all cells (PSCell and SCell) belonging to that SCG. For cells belonging to the deactivated SCG, UE 100 does not report CSI (Channel Status Information) for that cell, nor does it monitor PDCCH (Physical Downlink Control Channel). Furthermore, UE 100 does not send RACH (Random Access Channel), SRS (Sounding Reference Signal), and / or UL-SCH (UL-Shared Channel) to that cell. This suppresses the power consumption of UE 100.

[0079] UE 100 deactivates SCG using any of the following methods.

[0080] Method 1: UE 100 deactivates SCG in response to receiving an instruction to deactivate SCG from the master node (base station 200-1). This instruction is sent via any of the following: RRC layer signaling (RRC message), MAC layer signaling (MAC CE), and PHY layer signaling (PDCCH).

[0081] Method 2: UE 100 deactivates SCG in response to the expiration of the timer used to deactivate SCG.

[0082] (1.5) Separation of load-bearing capacity

[0083] In MR-DC, from the perspective of UE 100, there are three bearer types: MCG bearer, SCG bearer, and split bearer. The MCG bearer is configured between UE 100 and the primary node 200-1. The SCG bearer is configured between UE 100 and the secondary node 200-2. The split bearer is configured between UE 100 and the primary node 200-1, and is configured to be transmitted from UE 100 to the primary node 200-1 via the secondary node 200-2. The split bearer in MR-DC has both MCG RLC and SCG RLC radio bearers.

[0084] Figure 6 This diagram illustrates an example of a separate carrier used for UL data. Further details are provided later. Figure 6 As shown, if a separate bearer is configured, the PDCP entity 131 of UE 100 is associated with two RLC entities: the first RLC entity 132 and the second RLC entity 134.

[0085] Regarding UL data, PDCP entity 131 outputs a first PDCPPDU (Protocol Data Unit) (or a PDCP PDU corresponding to the first data) to the first RLC entity 132 corresponding to the master node 200-1. Additionally, PDCP entity 131 outputs a second PDCP PDU (or a PDCP PDU corresponding to the second data) to the second RLC entity 134 corresponding to the slave node 200-2.

[0086] Then, the first data is output to the PDCP entity 233 via the first RLC entity 132, the first MAC entity 133, the MAC entity 231 of the master node 200-1, and the RLC entity 232. On the other hand, the second data is output to the PDCP entity 233 via the second RLC entity 134, the second MAC entity 135, the MAC entity 234 of the slave node 200-2, and the RLC entity 235.

[0087] Thus, by using split bearers, the UE 100 is configured with two logical data paths, enabling it to send data to the primary node 200-1 and the secondary node 200-2 using two bearers. Specifically, when the total amount of PDCP data volume and RLC data volume reserved for initial transmission exceeds a threshold (ul-DataSplitTheshold), the PDCP entity 233 outputs the PDCP PDU to either the primary RLC entity (e.g., the first RLC entity 132) or the split secondary RLC entity (e.g., the second RLC entity 134).

[0088] Here, the PDCP data volume is the amount of data that can be sent in PDCP entity 131.

[0089] Furthermore, the configuration of the separate bearer can be achieved through negotiation between the master node 200-1 and the slave node 200-2, with the separate bearer configured in each node 200-1 and 200-2. Additionally, the separate bearer can be configured in UE100 by sending RRC messages from the master node 200-1 to UE100.

[0090] (1.6) Main Path

[0091] Master node 200-1 can configure the primary path for UE 100 using RRC messages. The primary path is indicated by the cell group ID and LCID (Logical Channel ID) of the primary RLC entity, which is capable of responding to a detached bearer action. Master node 200-1 uses RRC messages to indicate the cell group ID and LCID of the primary RLC entity. Therefore, UE 100 can configure the primary RLC entity side as the primary path. Figure 6 The example illustrates a scenario where the second RLC entity 134 is configured as the primary RLC entity, and the primary path is configured on the SCG side. Thus, the primary node 200-1 can configure the primary path on the SCG side.

[0092] Additionally, master node 200-1 can also configure a separate secondary path other than the primary path for UE 100 using RRC messages. A separate secondary path is a path indicated by the LCID of a separate secondary RLC entity, which is an RLC entity other than the primary RLC entity. Paths other than the primary path can be separate secondary paths. Master node 200-1 uses RRC messages to indicate the LCID of the separate secondary RLC entity. Therefore, UE 100 can configure the separate secondary RLC entity side as a separate secondary path. Figure 6 The example illustrates a scenario where the first RLC entity 132 is configured as a separate secondary RLC entity, and the separate secondary path is configured on the MCG side. Thus, the master node 200-1 can configure the separate secondary path on the MCG side.

[0093] For example, when the data volume of UE 100's PDCP entity 131 is less than a threshold, it sends a request to the primary RLC entity configured as the primary path (in... Figure 6 In the example, the second RLC entity 134 outputs a PDCP PDU. Furthermore, when the data volume exceeds a threshold, the PDCP entity 131 outputs a PDCP PDU to the path outside the main path, i.e., to the separate auxiliary RLC entity configured as the separate auxiliary path (in...). Figure 6 In the example, the first RLC entity 132 outputs PDCP PDU.

[0094] (1.7) Example of UE configuration

[0095] Figure 4 This is a diagram illustrating an example of the configuration of UE 100. (Example) Figure 4 As shown, UE 100 includes an antenna 101, a wireless communication unit 120, a control unit 130, and a memory 140.

[0096] Antenna 101 receives wireless signals transmitted from base station 200 and outputs the received wireless signals to wireless communication unit 120. Additionally, antenna 101 transmits wireless signals output from wireless communication unit 120 to base station 200.

[0097] Under the control of the control unit 130, the wireless communication unit 120 conducts wireless communication with the base station 200 via the antenna 101. For example, the wireless communication unit 120 converts (down-converts) the wireless signal output from the antenna 101 into a baseband signal (received signal) and outputs the converted baseband signal to the control unit 130. Alternatively, for example, the wireless communication unit 120 converts (up-converts) the baseband signal (transmitted signal) output from the control unit 130 into a wireless signal and outputs the converted wireless signal to the antenna 101.

[0098] The control unit 130 performs various controls within the UE 100. For example, the control unit 130 controls wireless communication with the base station 200 or with other UEs via the wireless communication unit 120. The control unit 130 can perform various operations by processing received signals output from the wireless communication unit 120. Furthermore, the control unit 130 can perform various operations and output transmitted signals to the wireless communication unit 120. The operations of the UE 100, described later, can be performed using the operations of the control unit 130.

[0099] Under the control of the control unit 130, the memory 140 stores various information. The memory 140 can function as the working memory of the control unit 130. Additionally, the memory 140 can also store programs. In this case, the control unit 130 reads the program from the memory 140 and executes it to implement actions in the UE 100. The memory 140 can be ROM (Read Only Memory) or RAM (Random Access Memory), etc.

[0100] (1.8) Example of base station configuration

[0101] Figure 5 This is a diagram illustrating an example of the configuration of base station 200. For example... Figure 5 As shown, the base station 200 includes an antenna 201, a wireless communication unit 220, a control unit 230, a memory 240, and a network communication unit 250.

[0102] Antenna 201 receives wireless signals transmitted from UE 100 and outputs the received wireless signals to wireless communication unit 220. Additionally, antenna 201 transmits wireless signals output from wireless communication unit 220 to UE 100.

[0103] Under the control of the control unit 230, the wireless communication unit 220 conducts wireless communication with the UE 100 via the antenna 201. For example, the wireless communication unit 220 converts (down-converts) the wireless signal output from the antenna 201 into a baseband signal (received signal) and outputs the converted baseband signal to the control unit 230. Alternatively, for example, the wireless communication unit 220 converts (up-converts) the baseband signal (transmitted signal) output from the control unit 230 into a wireless signal and outputs the converted wireless signal to the antenna 201.

[0104] The control unit 230 performs various controls within the base station 200. For example, the control unit 230 controls wireless communication with the UE 100 via the wireless communication unit 220. The control unit 230 can perform various operations by processing the received signals output from the wireless communication unit 220. Furthermore, the control unit 230 can perform various operations and output transmitted signals to the wireless communication unit 220.

[0105] Furthermore, the control unit 230 controls communication with the core network device 300 or other base stations via the network communication unit 250. The control unit 230 receives messages sent from the core network device 300 or other base stations via the network communication unit 250 and performs various actions. In addition, the control unit 230 performs various actions by instructing the network communication unit 250 to generate and send messages, enabling the network communication unit 250 to send various messages to the core network device 300 or other base stations.

[0106] The operation of the base station 200, which will be described later, can be achieved by utilizing the operation of the control unit 230.

[0107] Under the control of the control unit 230, the memory 240 stores various information. The memory 240 can function as the working memory of the control unit 230. Alternatively, the memory 240 can also store programs. In this case, the control unit 230 reads the program from the memory 240 and executes it to implement operations in the base station 200. The memory 240 can be ROM (Read-Only Memory), RAM (Random Access Memory), etc.

[0108] The network communication unit 250 is capable of communicating with other base stations. In this case, the network communication unit 250 communicates with other base stations using messages from the Xn interface. Additionally, the network communication unit 250 is capable of communicating with each node of the core network 30. In this case, the network communication unit 250 communicates with each node of the core network 30 using messages from the NG interface.

[0109] In the first embodiment, the UE 100 utilizes a dual-connectivity method, connecting to a primary base station 200-1 and a secondary base station 200-2. The UE 100 includes a wireless communication unit 120, configured to transmit first data belonging to a separate bearer to the primary base station 200-1 and second data belonging to a separate bearer to the secondary base station 200-2. Additionally, the UE 100 includes a control unit 130, which includes a PDCP entity 131, a first RLC entity 132 corresponding to the primary base station 200-1, and a second RLC entity 134 corresponding to the secondary base station 200-2. Furthermore, when the secondary cell group managed by the secondary base station 200-2 is inactive, the PDCP entity 131 outputs a PDCP data quantity indicating the amount of data available for transmission in the PDCP entity 131 to the first RLC entity 132, and outputs a PDCP data quantity of "0" to the second RLC entity 134. Therefore, when UE 100 is configured with a separate bearer, and the SCG is deactivated, UE 100 can appropriately send data to the MCG side. Details are explained in the following first and second action examples.

[0110] (2) Example of an action

[0111] (2-1) Example of the first action

[0112] Figure 6 This is a diagram illustrating an example of a separate bearer configuration according to an embodiment of this disclosure. Figure 6 In the example, UE 100 is configured with dual connectivity.

[0113] like Figure 6 As shown, UE 100 includes PDCP entity 131, first RLC entity 132, first MAC entity 133, second RLC entity 134, and second MAC entity 135. These entities are included, for example, in the control unit 130 of UE 100.

[0114] The main base station 200-1 includes a MAC entity 231, an RLC entity 232, and a PDCP entity 233. These entities are included, for example, in the control unit 230 of the main base station 200-1.

[0115] The secondary base station 200-2 includes a MAC entity 234 and an RLC entity 235. These entities are included, for example, in the control unit 230 of the secondary base station 200-2.

[0116] Here, the path from PDCP entity 131 via first RLC entity 132 to PDCP entity 233 of main base station 200-1 is configured as MCG. Additionally, in Figure 6 In the example, the path from PDCP entity 131 via the second RLC entity 134, from the RLC entity 235 of the auxiliary base station 200-2 to PDCP entity 233 is configured as SCG.

[0117] Additionally, a separate bearer is configured. Therefore, UE 100 can send the first data belonging to the separate bearer to the primary base station 200-1 via the MCG. Furthermore, UE 100 can send the second data belonging to the separate bearer to the secondary base station 200-2 via the SCG.

[0118] In addition, such as Figure 6 The image shows the state where the main path is configured on the SCG side.

[0119] In the first action example, under this state, with the SCG inactive, PDCP entity 131 maintains the primary path configuration while outputting a PDCP data volume to the first RLC entity 132. PDCP entity 131 outputs a PDCP data volume of "0" to the second RLC entity 134. Specifically, PDCP entity 131 outputs a PDCP data volume to the first RLC entity 132 (which is not currently suspended), and since the SCG is inactive, it outputs a PDCP data volume of "0" to the second RLC entity 134 (which is currently suspended).

[0120] The PDCP data volume output from PDCP entity 131 is output from first RLC entity 132 to first MAC entity 133. First MAC entity 133 generates a BSR (Buffer Status Report) based on the PDCP data volume. First MAC entity 133 sends the BSR to primary base station 200-1. MAC entity 231 of primary base station 200-1 uses scheduling to send a UL grant to UE 100 based on the BSR. First MAC entity 133 can then use the radio resources allocated by primary base station 200-1 to send data to primary base station 200-1 based on the UL grant.

[0121] On the other hand, since the SCG is inactive, the second RLC entity 134, which received the notification that the PDCP data volume is "0", does not output the PDCP data volume to the second MAC entity 135. Therefore, on the SCG side, UL grant is not received from the secondary base station 200-2, and UE 100 cannot use the SCG to send data.

[0122] Furthermore, in the first action example, PDCP entity 131 outputs PDCP PDU (Protocol Data Unit) to the first RLC entity 132, but does not output PDCP PDU to the second RLC entity 134.

[0123] The first RLC entity 132 converts the PDCP PDU output from the PDCP entity 131 into an RLC PDU and outputs it to the first MAC entity 133. The first MAC entity 133 converts the RLC PDU into a MAC PDU and outputs it to the PHY layer. The PHY layer converts the MAC PDU into a radio signal and uses the radio resources granted by UL to transmit the radio signal to the main base station 200-1. Thus, UE 100 is able to transmit UL data to the main base station 200-1.

[0124] On the other hand, since the PDCP PDU is not output to the second RLC entity 134, the UE 100 is able not to send UL data to the secondary base station 200-2.

[0125] Figure 7 This is a diagram illustrating examples of actions involved in embodiments of this disclosure. Furthermore, in Figure 7 Before the processing began, UE 100 was configured with dual connectivity and separate bearer.

[0126] like Figure 7 As shown, in step S10, the mobile communication system 1 begins processing.

[0127] In step S11, the control unit 230 of the main base station 200-1 configures the main path on the SCG side. The control unit 230 can configure the UE 100 to set the SCG side as the main path by sending an RRC message to the UE 100.

[0128] In step S12, the SCG is in an inactive (deactivate) state. For example, the control unit 230 of the main base station 200-1 detects that the SCG is inactive and sends an RRC message to the UE 100. Thus, the control unit 230 of the main base station 200-1 can notify the UE 100 that the SCG is inactive.

[0129] In step S13, PDCP entity 131 of UE 100 outputs PDCP data volume to the first RLC entity 132 that is not suspended. In addition, PDCP entity 131 outputs a notification to the second RLC entity 134 that the PDCP data volume is "0".

[0130] In step S14, PDCP entity 131 of UE 100 submits a PDCP PDU to the first RLC entity 132, which is not suspended. PDCP entity 131 does not submit a PDCP PDU to the second RLC entity 134, which is suspended.

[0131] Then, in step S15, the mobile communication system 1 ends a series of processes.

[0132] Thus, in the first action example, in the mobile communication system 1, when dual connectivity is configured, separate bearer is configured, and the main path is configured in SCG, the PDCP entity 131 performs a predetermined action when SCG is inactive.

[0133] That is, PDCP entity 131 outputs PDCP data volume to the first RLC entity 132 that is not suspended, and outputs a notification to the second RLC entity 134 that the PDCP data volume is "0".

[0134] In addition, PDCP entity 131 outputs PDCP PDU to the first RLC entity 132 that is not suspended, but does not output PDCP PDU to the second RLC entity 134 that is suspended.

[0135] Therefore, when UE 100 is configured with a separate bearer, and SCG is deactivated, UE 100 can appropriately send data to the MCG side.

[0136] Figure 8 as well as Figure 9 This is a diagram representing examples of actions in the specification. Among them, Figure 8 This represents a PDCP PDU transmission example.

[0137] like Figure 8 As shown in (X), when neither the main RLC entity nor the separate auxiliary RLC entity is suspended, a PDCP PDU is output to either the main RLC entity or the separate auxiliary RLC entity.

[0138] In addition, such as Figure 8 As shown in (Y), if either the main RLC entity or the separate auxiliary RLC entity is suspended, a PDCP PDU is output to the unsuspended RLC entity.

[0139] In the first action example, the case where the main RLC entity is configured as the second RLC entity 134 and the separate auxiliary RLC entity is configured as the first RLC entity 132 through the main path configuration is explained.

[0140] Figure 9 This is a diagram illustrating an example of PDCP data volume transmission. For example... Figure 9 As shown in (X), when neither the main RLC entity nor the separate auxiliary RLC entity is suspended, the PDCP data volume is output to either the main RLC entity or the separate auxiliary RLC entity.

[0141] In addition, such as Figure 9 As shown in (Y), if either the main RLC entity or the separate auxiliary RLC entity is suspended, a PDCP data volume is output to the unsuspended RLC entity. Additionally, outputting a PDCP data volume of "0" to the suspended RLC entity indicates this.

[0142] Furthermore, in the first action example, an example of sending data to the MCG without changing the RRC configuration and with the SCG in an inactive state was described. Specifically, an example of not changing the main path configuration was described. Thus, in the first action example, by not performing the processing for changing the RRC configuration, the processing in the mobile communication system 1 can be reduced, and processing latency can be decreased.

[0143] On the other hand, the second action example, which will be explained next, is an example of changing the RRC configuration. Specifically, it is an example of changing the configuration of the main path.

[0144] (2-2) Example of the second action

[0145] Figure 10 This is a diagram illustrating a configuration example of a separate bearer according to an embodiment of this disclosure.

[0146] exist Figure 10 In the example, similar to the first action example, dual connectivity is configured in mobile communication system 1. Therefore, the path from PDCP entity 131 via first RLC entity 132 to PDCP entity 233 of primary base station 200-1 is configured as MCG. On the other hand, the path from PDCP entity 131 of UE 100 via second RLC entity 134, via secondary base station 200-2 to PDCP entity 233 of primary base station 200-1 is configured as SCG.

[0147] Furthermore, in mobile communication system 1, a separate bearer is configured. Moreover, in mobile communication system 1, the main path is configured on the SCG side.

[0148] In the second action example, under such conditions, when the SCG is inactive, the main base station 200-1 will configure (change) the main path from the SCG to the MCG.

[0149] Specifically, the primary base station 200-1 is connected to the primary base station of the UE 100 together with the secondary base station 200-2 using a dual-connectivity method. The primary base station 200-1 includes a wireless communication unit 220, which receives first data belonging to a separate bearer from the UE 100 and second data belonging to a separate bearer from the UE 100 via the secondary base station 200-2. Furthermore, the primary base station 200-1 includes a control unit 230, which configures the UE 100 to switch its primary path from the secondary cell group to the primary cell group managed by the primary base station 200-1 when the secondary cell group managed by the secondary base station 200-2 is inactive.

[0150] On the other hand, when the secondary cell group is inactive, the control unit 130 of UE 100 switches the primary path from the secondary cell group to the primary cell group managed by the primary base station 200-1. Then, the PDCP entity 131 of UE 100 outputs PDCP data to the first RLC entity 132, which is the primary RLC entity, and outputs PDCP data of "0" to the second RLC entity 134, which is the separate secondary RLC entity.

[0151] In addition, PDCP entity 131 outputs PDCP PDU to the first RLC entity 132, which is the main RLC entity, but does not output PDCP PDU to the second RLC entity 134, which is a separate auxiliary RLC entity.

[0152] Figure 11 This is a diagram illustrating examples of actions involved in embodiments of this disclosure. Furthermore, in Figure 11 Before the processing began, UE 100 was configured with dual connectivity and separate bearer.

[0153] In step S20, the mobile communication system 1 begins processing.

[0154] In step S21, the main base station 200-1 configures the main path on the SCG side. For example, the control unit 230 of the main base station 200-1 sends an RRC message to the UE 100, the RRC message indicating that the main path is configured on the SCG side.

[0155] Figure 14 This is a diagram illustrating an example of information included in a message related to an embodiment of this disclosure. Figure 14 This represents an example of the "PDCP-Config Information element" included in an RRC message. For example... Figure 14 As shown in (X), "PrimaryPath" is included as an information element in this information element.

[0156] Figure 15 This is an explanatory diagram of "PrimaryPath". For example... Figure 15 As stated in the first sentence, "PrimaryPath" refers to the information element indicating the primary RLC entity among multiple RLC entities. The control unit 230 of the primary base station 200-1 designates the cell group ID and LCID of the second RLC entity 134 as the primary RLC entity in "PrimaryPath". Therefore, it is possible to configure the primary path including the SCG of the second RLC entity 134.

[0157] In the second action example, further, such as Figure 15 As shown in (X), when the SCG is inactive, the information for configuring the cell group ID corresponding to the MCG for UE100 can be included in "PrimaryPath".

[0158] That is, the primary base station 200-1 sends an RRC message to the UE 100, which also includes a "PDCP-Config Information element" that includes a "PrimaryPath". Moreover, when the SCG is inactive, the UE 100 can configure the primary path to the SCG according to the configuration indicated in the "PrimaryPath".

[0159] Furthermore, through the configuration of "PrimaryPath", the control unit 130 of UE 100 changes the first RLC entity 132 from a separate secondary RLC entity to a primary RLC entity. On the other hand, the control unit 130 changes the second RLC entity 134 from a primary RLC entity to a separate secondary RLC entity through the configuration of "PrimaryPath".

[0160] Return to Figure 11 In step S22, SCG is in an inactive state.

[0161] In step S23, the control unit 130 of UE 100 configures the primary path on the MCG side. As described above, the MCG is configured as the primary path according to the configuration of the "PrimaryPath" included in the information element "PDCP-Config Information element" received in step S21.

[0162] In step S24, PDCP entity 131 of UE 100 outputs PDCP data volume to the primary RLC entity (first RLC entity 132). Additionally, PDCP entity 131 outputs PDCP data volume as "0" to the separate secondary RLC entity (second RLC entity 134). Therefore, similar to the first action example, in the second action example, the primary base station 200-1 only sends UL grant to the MCG side of UE 100.

[0163] In step S25, PDCP entity 131 outputs PDCP PDU to the main RLC entity (first RLC entity 132). However, PDCP entity 131 does not output PDCP PDU to the separate auxiliary RLC entity (second RLC entity 134).

[0164] Then, in step S26, the mobile communication system 1 ends a series of processes.

[0165] Thus, in the second action example, similar to the first action example, when the UE 100 is configured with a separate bearer, the UE 100 can appropriately send data to the MCG side when the SCG is deactivated.

[0166] Figure 12 as well as Figure 13 This is a diagram representing examples of actions in the specification. Among them, Figure 12 This represents a PDCP PDU transmission example.

[0167] like Figure 12As shown in (X), when a separate auxiliary RLC entity (e.g., the second RLC entity 134) is suspended due to the deactivation of the SCG, the PDCP PDU is submitted to the unsuspended main RLC entity (e.g., the first RLC entity 132). On the other hand, when the separate auxiliary RLC entity is not suspended, the PDCP PDU is submitted to either the main RLC entity or the separate auxiliary RLC entity.

[0168] Figure 13 This represents an example of PDCP data volume transmission. For example... Figure 13 As shown in (X), when a separate secondary RLC entity is suspended due to the deactivation of the SCG, the PDCP data volume is indicated to the MAC entity associated with the primary RLC entity. On the other hand, the PDCP data volume is indicated as "0" to the MAC entity associated with an RLC entity other than the primary RLC entity (or a separate secondary RLC entity).

[0169] Furthermore, if the separate auxiliary RLC entity is not suspended and the total amount of PDCP data and RLC data reserved for initial transmission is above the threshold, the PDCP data volume is output to both the main RLC entity and the separate auxiliary RLC entity.

[0170] [Other Implementation Methods]

[0171] The aforementioned action examples are not limited to being implemented independently; they can also be implemented by appropriately combining the action examples. Furthermore, for example, the steps in the process described in this specification are not necessarily executed in chronological order as shown in the flowchart or sequence diagram. For example, the steps in the process may be executed in a different order than that shown in the flowchart or sequence diagram, or they may be executed in parallel. Additionally, a part of a step in the process may be deleted, or further steps may be added to the process.

[0172] Alternatively, for example, a method for operating one or more constituent elements of the apparatus described in this specification may be provided, or a program for causing a computer to perform the operation of the aforementioned constituent elements may be provided. The program may be recorded on a computer-readable medium. Using a computer-readable medium, an installation program can be installed on a computer. Here, the computer-readable medium on which the program is recorded may also be a non-transient recording medium. There are no particular limitations on the non-transient recording medium, but it may be, for example, a recording medium such as a CD-ROM or DVD-ROM. As an example of such a recording medium, the aforementioned memories 140 and 240 are provided.

[0173] Alternatively, the circuitry for each process performed by the UE 100 or base station 200 can be integrated, and at least a portion of the UE 100 or base station 200 can be configured as a semiconductor integrated circuit (chipset, SoC).

[0174] It should be understood that although this disclosure has been described with reference to embodiments, it is not limited to those embodiments or constructions. This disclosure also includes various modifications and equivalent variations. Furthermore, various combinations, methods, and other combinations and methods that include only one element, more or fewer elements also fall within the scope and spirit of this disclosure.

Claims

1. A communication device (100) is a communication device (100) that is connected to a master node (200-1) associated with a primary cell group (MCG) and a secondary node (200-2) associated with a secondary cell group (SCG) using a dual-connection method, comprising: The control unit (130) includes a Packet Data Convergence Protocol (PDCP) entity (131) corresponding to the separate bearer, a primary radio link control (RLC) entity (132) corresponding to the PDCP entity, and a secondary RLC entity (134) corresponding to the PDCP entity; and The receiving unit (120), when the SCG is deactivated, receives a Radio Resource Control (RRC) message, the RRC message including the ID of the cell group corresponding to the primary RLC entity. The ID of the cell group corresponding to the primary RLC entity corresponds to the MCG. When the total amount of PDCP data and RLC data reserved for initial transmission is less than a threshold, the PDCP entity (131) outputs PDCP protocol data unit (PDU) to the main RLC entity (132).

2. In the communication device (100) according to claim 1, if the total amount of the PDCP data and the RLC data reserved for initial transmission is less than a threshold, the PDCP entity (131) indicates the PDCP data to the Media Access Control (MAC) entity corresponding to the main RLC entity.

3. The communication device (100) according to claim 1, wherein the receiving unit (120) receives the RRC message including information indicating the deactivation of the SCG.

4. A master node (200-1) is connected to a secondary node (200-2) associated with a secondary cell group (SCG) and a communication device (100) via a dual-connection method, wherein the master node (200-1) is associated with a primary cell group (MCG), and the master node (200-1) comprises: The control unit (230) includes a Packet Data Convergence Protocol (PDCP) entity (233) corresponding to the separate bearer, a primary radio link control (RLC) entity (232) corresponding to the PDCP entity, and a secondary RLC entity (235) corresponding to the PDCP entity; and The transmitting unit (220), when the SCG is deactivated, sends a Radio Resource Control (RRC) message to the communication device (100), the RRC message including the ID of the cell group corresponding to the primary RLC entity. The ID of the cell group corresponding to the main RLC entity corresponds to the MCG.

5. The master node (200-1) according to claim 4, wherein the transmitting unit (220) sends the RRC message including information indicating the deactivation of the SCG to the communication device (100).

6. A communication control method, which is a communication control method at a communication device (100), wherein the communication device (100) is connected to a primary node (200-1) associated with a primary cell group (MCG) and a secondary node (200-2) associated with a secondary cell group (SCG) using a dual-connection method. The communication device (100) includes a Packet Data Convergence Protocol (PDCP) entity (131) corresponding to the separate bearer, a primary radio link control (RLC) entity (132) corresponding to the PDCP entity, and a secondary RLC entity (134) corresponding to the PDCP entity. The communication control method includes: When the SCG is deactivated, the step of receiving a Radio Resource Control (RRC) message, the RRC message including the ID of the cell group corresponding to the primary RLC entity, the ID of the cell group corresponding to the primary RLC entity corresponding to the MCG; and The step of the PDCP entity (131) outputting PDCP protocol data unit (PDU) to the main RLC entity (132) when the total amount of PDCP data and RLC data reserved for initial transmission is less than a threshold.

7. The communication control method according to claim 6 further includes: The step of receiving the RRC message which includes information indicating the deactivation of the SCG.

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