Communication control method and node

Abstract

To provide a communication control method and a node that allow a user equipment to hand over to an optimal cell according to a service type.SOLUTION: A communication control method includes a step of a node receiving, from a core network device, a first message including at least one of network slice information related to a network slice and service quality information representing quality of service. The communication control method also includes a step of the node receiving a measurement report from a user equipment. The communication control method further includes a step of the node determining a threshold value to be used for determining whether or not to hand over based on at least one of the network slice information and the service quality information in response to receiving the measurement report. The communication control method further includes a step of the node determining whether or not to cause the user equipment to hand over based on a reception quality value representing the reception quality included in the measurement report and the threshold value.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a communication control method and node Regarding. [Background technology]

[0002] Handover is one of the mobility controls applied to user equipment (UE: User Equipment) in the RRC connected state. Handover is a technique for user equipment to switch the cell to which it is connected. node Measures the reception quality according to the configuration information (MeasConfig) provided by and generates a measurement report (MeasurementReport) including the reception quality. node Send to. node The measurement report is used to determine whether to perform a handover and to instruct the user equipment to perform the handover. The handover enables the user equipment to perform wireless communication between the user equipment and an optimal cell, for example.

[0003] Meanwhile, network slicing has been introduced in mobile communication systems. Network slicing is a technology that creates multiple virtual networks by virtually dividing a physical network constructed by a carrier. Each virtual network is called a network slice. Network slicing allows a communication carrier to create slices according to the service requirements of different service types, such as eMBB (enhanced Mobile Broadband), URLLC (Ultra-Reliable and Low Latency Communications), and mMTC (massive Machine Type Communications). Network slicing can, for example, optimize network resources. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] 3GPP TS 38.300 V17.4.0 (2023-03) [Non-Patent Document 2] 3GPP TS 38.401 V17.5.0 (2023-06) [Non-Patent Document 3] 3GPP TS 23.501 V17.9.0 (2023-06) Summary of the Invention [Problem to be solved by the invention]

[0005] however, node In the LTE-2000, the handover decision is made based on the reception quality included in the measurement report, regardless of the service type corresponding to the network slice, so that the user equipment may not be able to handover to the optimal cell according to the service type.

[0006] Therefore, the present disclosure provides a communication control method and node The purpose is to provide. [Means for solving the problem]

[0007] A communication control method according to one embodiment is a communication control method in a mobile communication system, comprising the steps of: node The communication control method further includes a step of receiving a first message from a core network device, the first message including at least one of network slice information related to a network slice and service quality information representing a quality of a service. node receiving a measurement report from the user equipment. node determining a threshold value used for determining whether or not to execute a handover based on at least one of network slice information and service quality information in response to receiving the measurement report. nodeBased on a reception quality value indicating reception quality included in the measurement report and a threshold value, the user equipment of Handover Whether to allow of decision The method includes the step of:

[0008] In addition, according to one embodiment node is capable of communicating with user equipment and core network equipment node The above node The receiving unit receives a first message including at least one of network slice information related to a network slice and service quality information representing a quality of a service from a core network device, and receives a measurement report from a user device. node The control unit determines a threshold value used for handover decision based on at least one of network slice information and service quality information in response to receiving the measurement report. The control unit determines a threshold value used for handover decision based on a reception quality value and the threshold value included in the measurement report. of Handover Whether to allow of decision do. Effect of the Invention

[0009] According to the present disclosure, a communication control method and node can be provided. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a mobile communication system according to the first embodiment. [Diagram 2] FIG. 2 is a diagram illustrating an example of the configuration of a UE (user equipment) according to the first embodiment. [Diagram 3] FIG. 3 is a diagram illustrating an example configuration of a gNB (node) according to the first embodiment. [Figure 4] FIG. 4 is a diagram illustrating an example of the configuration of an AMF according to the first embodiment. [Diagram 5]FIG. 5 is a diagram illustrating an example of the configuration of a protocol stack of a user plane according to the first embodiment. [Figure 6] FIG. 6 is a diagram illustrating an example of the configuration of a protocol stack of a control plane according to the first embodiment. [Figure 7] FIG. 7 is a diagram illustrating an example of operation according to the first embodiment. [Figure 8] FIG. 8(A) shows an example of association according to the first embodiment, and FIG. 8(B) shows an example of association according to the second embodiment. [Figure 9] FIG. 9 is a diagram illustrating an example of operation according to the first embodiment. [Figure 10] FIG. 10(A) shows an example of information elements included in a UE context modification request message according to the first embodiment, and FIG. 10(B) shows an example of information elements included in "CU to DU RRC information" according to the first embodiment. [Figure 11] FIG. 11 is a diagram illustrating an example of 5QI according to the first embodiment. [Figure 12] FIG. 12 is a diagram illustrating an example of operation according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] [First embodiment] Hereinafter, the embodiments will be described in detail with reference to the drawings. In the description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

[0012] (Configuration of a mobile communication system) First, a configuration example of a mobile communication system according to the first embodiment will be described.

[0013] Fig. 1 is a diagram showing the configuration of a mobile communication system 1. The mobile communication system 1 complies with the 5th Generation System (5GS) of the 3GPP (registered trademark) standard. In the following description, 5GS is taken as an example, but the mobile communication system may be at least partially applied with a Long Term Evolution (LTE) system, or at least partially applied with a sixth generation (6G) system. The mobile communication system 1 shown in Fig. 1 may be a 5G system.

[0014] The mobile communication system 1 includes a user equipment (UE) 100 and a gNB ( node ) 200 and an access and mobility management function (AMF) 300.

[0015] The AMF 300 is an example of a core network device. Although not shown in FIG. 1, other core network devices include a Session Management Function (SMF) and a User Plane Function (UPF). On the other hand, the gNB 200 is a device connected to a core network (CN). node This is an example of the following. node As an example, we will use gNB200. node is LTE (Long Term Evolution) node It may be an eNB (evolved Node B) that is 6G or later. node may be also possible.

[0016] The UE 100 is a mobile wireless communication device. The UE 100 may be any device that is used by a user, and may be, for example, a mobile phone terminal (including a smartphone), a tablet terminal, a notebook PC, a communication module (including a communication card or a chipset), a sensor or a device provided in a sensor, a vehicle or a device provided in a vehicle (Vehicle UE), an aircraft or a device provided in an aircraft (Aerial UE, or a UAV (Unmanned Aerial Vehicle)). Alternatively, the UE 100 may be an IoT (Internet of Things) device, an IoT sensor, or the like.

[0017] The gNB200 is node The gNB 200 is connected to each other via an Xn interface, which is an interface between the gNB 200 and the UE 100. The gNB 200 manages one or more cells. The gNB 200 performs wireless communication with the UE 100 that has established a connection with its own cell. The gNB 200 has a radio resource management (RRM) function, a routing function for user data (hereinafter simply referred to as "data"), a measurement control function for mobility control and scheduling, etc. The term "cell" is used to indicate the smallest unit of a wireless communication area. The term "cell" is also used to indicate a function or resource for performing wireless communication with the UE 100. One cell belongs to one carrier frequency (hereinafter simply referred to as "frequency").

[0018] The gNB200 can also connect to the EPC (Evolved Packet Core), which is the LTE core network. node (eNB: evolved Node B) can also connect to 5G networks. node and gNB200 node They can also be connected via an interface.

[0019] The AMF 300 performs various mobility controls for the UE 100. The AMF 300 can communicate with the UE 100 using a NAS message on the N1 interface. The AMF 300 can also communicate with the gNB 200 using an N2 message on the N2 interface. By performing such communication, the AMF 300 performs mobility management for the UE 100 and location management for the UE 100. The AMF 300 is connected to the SMF via a network.

[0020] (Example of UE configuration) First, a configuration example of the UE 100 will be described.

[0021] 2 is a diagram illustrating an example of the configuration of the UE 100 (user equipment) according to the first embodiment. The UE 100 includes a receiving unit 110, a transmitting unit 120, and a control unit 130. The receiving unit 110 and the transmitting unit 120 configure a wireless communication unit that performs wireless communication with the gNB 200.

[0022] The receiving unit 110 performs various receptions under the control of the control unit 130. The receiving unit 110 includes an antenna and a receiver. The receiver converts a radio signal received by the antenna into a baseband signal (received signal) and outputs the baseband signal to the control unit 130.

[0023] The transmission unit 120 performs various transmissions under the control of the control unit 130. The transmission unit 120 includes an antenna and a transmitter. The transmitter converts a baseband signal (transmission signal) output by the control unit 130 into a radio signal and transmits it from the antenna.

[0024] The control unit 130 performs various controls and processes in the UE 100. Such processes include processes of each layer described later. The control unit 130 includes at least one processor and at least one memory. The memory stores a program executed by the processor and information used in the processes by the processor. The processor may include a baseband processor and a CPU (Central Processing Unit). The baseband processor performs modulation / demodulation and encoding / decoding of a baseband signal. The CPU executes a program stored in the memory to perform various processes. Note that the processes or operations in the UE 100 described later may be performed by the control unit 130. Also, the transmission of a message in the UE 100 described later may be performed by the transmission unit 120, and the reception of a message in the UE 100 may be performed by the reception unit 110.

[0025] (Example of gNB configuration) Next, an example configuration of gNB200 will be described.

[0026] FIG. 3 shows the gNB 200 ( node 2 is a diagram showing the configuration of the gNB 200. The gNB 200 includes a transmitter 210, a receiver 220, a controller 230, and a network communication unit 250. The transmitter 210 and the receiver 220 constitute a wireless communication unit that performs wireless communication with the UE 100. The network communication unit 250 constitutes a network communication unit that performs communication with the AMF 300.

[0027] The transmission unit 210 performs various transmissions under the control of the control unit 230. The transmission unit 210 includes an antenna and a transmitter. The transmitter converts a baseband signal (transmission signal) output by the control unit 230 into a radio signal and transmits it from the antenna.

[0028] The receiving unit 220 performs various receptions under the control of the control unit 230. The receiving unit 220 includes an antenna and a receiver. The receiver converts a radio signal received by the antenna into a baseband signal (received signal) and outputs the baseband signal to the control unit 230.

[0029] The control unit 230 performs various controls and processes in the gNB 200. Such processes include processes of each layer described later. The control unit 230 includes at least one processor and at least one memory. The memory stores a program executed by the processor and information used in the processes by the processor. The processor may include a baseband processor and a CPU. The baseband processor performs modulation / demodulation and encoding / decoding of a baseband signal. The CPU executes a program stored in the memory to perform various processes. Note that the processes or operations in the gNB 200 described later may be performed by the control unit 230. In addition, the transmission of a message in the gNB 200 described later may be performed by the transmission unit 210 and the network communication unit 250, and the reception of a message in the gNB 200 may be performed by the reception unit 220 and the network communication unit 250.

[0030] The network communication unit 250 includes: node - The network communication unit 250 is connected to the AMF 300 via an NG interface, which is an interface between core networks. Specifically, the network communication unit 250 is connected to the AMF 300 via an N2 interface. The network communication unit 250 is also connected to other gNBs via an Xn interface. The network communication unit 250 may also perform various processes under the control of the control unit 230.

[0031] The gNB 200 may be configured (i.e., functionally divided) with a central unit (CU) 231 and a distributed unit (DU) 232. In this case, both units may be connected by an F1 interface, which is a fronthaul interface. As shown in FIG. 3, the CU 231 and the DU 232 may be included in the control unit 230. Alternatively, the CU 231 may include a first control unit, and the DU 232 may include a second control unit. Regarding the functional division, the wireless communication unit may constitute an RU (Radio Unit). One RU may have one cell or may have multiple cells. The CU 231 and the DU 232 may be connected by an F1 interface, which is a midhaul interface. The DU 232 and the RU may be connected by an O-RAN (Open Radio Access Network) interface, which is a fronthaul interface. The CU 231 and the core network device may be connected by an NG interface, and the CU 231 and other gNBs may be connected by an Xn interface. Hereinafter, the CU may be referred to as a "gNB-CU". DU may also be referred to as "gNB-DU."

[0032] (AMF configuration example) Next, a configuration example of the AMF 300 will be described.

[0033] 4 is a diagram illustrating an example of the configuration of the AMF 300 according to the first embodiment. As shown in FIG. 4, the AMF 300 includes a receiving unit 310, a transmitting unit 320, and a control unit 330.

[0034] The receiving unit 310 performs various reception operations under the control of the control unit 330. The receiving unit 310 receives a message (for example, a message via the N2 interface) transmitted from the gNB 200. The receiving unit 310 outputs the received message to the control unit 330.

[0035] The transmitting unit 320 performs various transmissions under the control of the control unit 330. The transmitting unit 320 transmits a message received from the control unit 330 (e.g., a message via the N2 interface) to the gNB 200. In addition, the transmitting unit 320 transmits a message received from the control unit 330 (e.g., a message via the N11 interface) to another core network device (e.g., an SMF).

[0036] The control unit 330 performs various controls and processes in the AMF 300. The control unit 330 includes at least one processor and at least one memory. The memory stores programs executed by the processor and information used in the processes by the processor. The processor may include a CPU. The CPU executes programs stored in the memory to perform various processes. Note that the processes or operations in the AMF 300 described below may be performed by the control unit 330. Also, the transmission of messages in the AMF 300 described below may be performed by the transmitting unit 320, and the reception of messages in the AMF 300 may be performed by the receiving unit 310.

[0037] (User plane protocol stack) 5 is a diagram showing a configuration of a user plane protocol stack that handles data. The user plane protocol includes a radio interface protocol between the UE 100 and the gNB 200 and a wired interface protocol between the gNB 200 and the UPF.

[0038] The user plane radio interface protocol includes a physical (PHY) layer, a medium access control (MAC) layer, a radio link control (RLC) layer, a packet data convergence protocol (PDCP) layer, and a service data adaptation protocol (SDAP) layer.

[0039] The PHY layer performs coding / decoding, modulation / demodulation, antenna mapping / demapping, and resource mapping / demapping. Data and control information are transmitted between the PHY layer of the UE 100 and the PHY layer of the gNB 200 via a physical channel. The PHY layer of the UE 100 receives downlink control information (DCI) transmitted from the gNB 200 on a physical downlink control channel (PDCCH). Specifically, the UE 100 performs blind decoding of the PDCCH using a radio network temporary identifier (RNTI) and acquires the successfully decoded DCI as DCI addressed to the UE. The DCI transmitted from the gNB 200 has CRC parity bits scrambled by the RNTI added thereto.

[0040] The MAC layer performs data priority control, retransmission processing using hybrid ARQ (HARQ), random access procedures, etc. Data and control information are transmitted between the MAC layer of the UE 100 and the MAC layer of the gNB 200 via a transport channel. The MAC layer of the gNB 200 includes a scheduler. The scheduler determines the uplink and downlink transport format (transport block size, modulation and coding scheme (MCS)) and the resource blocks to be assigned to the UE 100.

[0041] The RLC layer transmits data to the RLC layer on the receiving side by using the functions of the MAC layer and the PHY layer. Data and control information are transmitted between the RLC layer of the UE 100 and the RLC layer of the gNB 200 via a logical channel.

[0042] The PDCP layer performs header compression / decompression, encryption / decryption, etc.

[0043] The SDAP layer maps IP flows, which are the units for QoS control by the core network, to radio bearers, which are the units for QoS control by the AS (Access Stratum). Note that if the RAN is connected to the EPC, the SDAP is not necessary.

[0044] The wired interface protocol of the user plane includes L1 (Layer 1), L2 (Layer 2), an IP (Internet Protocol) layer, a UDP (User Datagram Protocol) layer, and GTP-U (GPRS Tunneling Protocol for User Plane).

[0045] The L1 layer corresponds to the PHY layer in the radio interface protocol of the user plane. The L2 layer includes the MAC layer in the radio interface protocol of the user plane. The L2 layer is also called the data link layer.

[0046] The IP layer corresponds to the Internet layer. IP packets are sent and received between the IP layer of the gNB 200 and the IP layer of the UPF using IP addresses.

[0047] The UDP layer corresponds to the transport layer. UDP packets can be sent between the UDP layer of the gNB200 and the UDP layer of the UPF without waiting for a response from the communication partner.

[0048] The GTP-U layer is a layer that transmits and receives user plane PDUs (Protocol Data Units) using the General Packet Radio Service (GPRS) tunneling protocol. GTP-U packets are transmitted and received between the GTP-U layer of the gNB 200 and the GTP-U layer of the UPF. The GPRS tunnel is identified by a Tunnel Endpoint Identifier (TEID).

[0049] (Control Plane Protocol Stack) FIG. 6 is a diagram showing the configuration of a protocol stack of a radio interface of a control plane that handles signaling (control signals).

[0050] The protocol stack of the radio interface of the control plane has a Radio Resource Control (RRC) layer and a Non-Access Stratum (NAS) instead of the SDAP layer shown in FIG.

[0051] Between the RRC layer of the UE 100 and the RRC layer of the gNB 200, RRC signaling for various settings is transmitted. The RRC layer controls logical channels, transport channels, and physical channels in response to establishment, re-establishment, and release of radio bearers. When there is a connection (RRC connection) between the RRC of the UE 100 and the RRC of the gNB 200, the UE 100 is in an RRC connected state. When there is no connection (RRC connection) between the RRC of the UE 100 and the RRC of the gNB 200, the UE 100 is in an RRC idle state. When the connection between the RRC of the UE 100 and the RRC of the gNB 200 is suspended, the UE 100 is in an RRC inactive state.

[0052] The NAS, which is located above the RRC layer, performs session management, mobility management, and the like. NAS signaling is transmitted between the NAS of the UE 100 and the NAS of the AMF 300. The UE 100 has an application layer and the like in addition to the radio interface protocol. The layer below the NAS is called an AS (Access Stratum).

[0053] (Handover) As described above, handover is, for example, a technique in which the UE 100 switches a cell to which the UE 100 is connected. The UE 100 performs measurement according to the configuration information (MeasConfig) received from the gNB 200. The configuration information (MeasConfig) is transmitted from the gNB 200 to the UE 100 by using an RRC message such as an RRCReconfiguration message or an RRCResume message.

[0054] The configuration information (MeasConfig) may include a measurement object (MeasObject), a report configuration (ReportConfig), a measurement ID (MeasID), and a measurement gap (MeasGap), etc.

[0055] The measurement object (MeasObject) includes information for identifying the synchronization signal block (SSB) to be measured. Specifically, the measurement object (MeasObject) may include information indicating that the measurement object is the synchronization signal block (SSB). Alternatively, the measurement object (MeasObject) may include information indicating the frequency and time position of the synchronization signal block to be measured. Alternatively, the measurement object (MeasObject) may include a list of cells to be measured (white list) and / or a list of cells not to be measured (black list).

[0056] The report configuration (ReportConfig) includes information for specifying a criterion for triggering a measurement report. Specifically, the report configuration (ReportConfig) may include information such as a report interval when the measurement report is performed periodically. Alternatively, the report configuration (ReportConfig) may include information on each event when the measurement report is performed by an event trigger (for example, each event, and a threshold, an offset value, and / or a hysteresis value used in each event). The events include a serving cell (a serving cell) becoming better than a threshold (event A1), a serving cell becoming worse than a threshold (event A2), a neighboring cell becoming better than the serving cell by an offset (event A3), a neighboring cell becoming better than a threshold (event A4), and a serving cell becoming worse than a first threshold and a neighboring cell becoming better than a second threshold (event A5). Alternatively, the report configuration (ReportConfig) may include information indicating which of the received power (RSRP: Reference Signal Received Power), the reference signal received quality (RSRQ: Reference Signal Received Quality), and the signal to interference plus noise ratio (SINR: Signal to Interference plus Noise Ratio) is to be measured as the quality (reception quality).

[0057] The measurement ID (MeasID) is used to identify the configuration information (MeasurementConfig) and links the measurement object (MeasurementObject) and the measurement report (MeasurementReport).

[0058] The measurement gap (MeasGap) includes information for setting a period (measurement gap) during which the UE 100 performs measurement.

[0059] The UE 100 measures the reception quality of the cell according to the configuration information (MeasConfig). The UE 100 may measure at least one beam of the cell and average the measurement results to measure the reception quality. The UE 100 transmits a measurement report (MeasurementReport) including the reception quality as a measurement result (MeasResults) to the gNB 200 according to the configuration information. The measurement report is also a message transmitted when the UE 100 satisfies a condition related to an event trigger, for example.

[0060] The gNB 200 determines a handover decision for the UE 100 based on the reception quality. That is, the gNB 200 determines whether or not to execute handover in the UE 100 based on the reception quality. When the gNB 200 determines to execute handover to the UE 100, it transmits an RRC message (e.g., an RRC reconfiguration message) including information required for accessing the target cell to the UE 100. By receiving the RRC message, the UE 100 knows that handover is possible, and starts a connection to the target cell using the information included in the RRC message.

[0061] (Network Slice) The network slice is set on a network configured with the NG-RAN 10 and the 5GC 20. One or more network slices can be set on the network. Each network slice is associated with one service type. Examples of the service types include eMBB, URLLC, MIoT (Massive Internet of Things), V2X (Vehicle to Everything), and HMTC (High Performance Machine Type Communication). For example, the service type eMBB is associated with network slice #1, the service type MIoT is associated with network slice #2, and the service type HMTC is associated with network slice #3.

[0062] In the following, a network slice may simply be referred to as a "slice."

[0063] Each slice is provided with a slice identifier for identifying the slice. An example of a slice identifier is S-NSSAI (Single Network Slicing Selection Assistance Information). S-NSSAI includes 8-bit SST (slice / service type). S-NSSAI may further include 24-bit SD (slice differentiator).

[0064] SST is an example of service type information indicating a service type to which a slice is associated. For example, SST=1 indicates eMBB, SST=2 indicates URLLC, SST=3 indicates MIoT, SST=4 indicates V2X, and SST=5 indicates HMTC. However, these are only examples, and other service types may be associated with each SST, or other service types may be associated with other SST values.

[0065] The SD is information for differentiating a plurality of slices associated with the same service type.

[0066] Information containing multiple S-NSSAIs is called NSSAI (Network Slice Selection Assistance Information).

[0067] Also, one or more slices may be grouped to configure a slice group. Also, a slice group is a group including one or more slices, and a slice group identifier is assigned to the slice group. The slice group may be configured by a core network (e.g., AMF300) or may be configured by a radio access network (e.g., gNB200). The configured slice group may be notified to the UE100.

[0068] (Operation example according to the first embodiment) Next, an operation example according to the first embodiment will be described.

[0069] 7 and 9 are diagrams showing an example of operation according to the first embodiment. Fig. 7 shows an example in which the UE 100 performs handover from a source DU 232-1 accommodating a source cell to a target DU 232-2 accommodating a target cell. Fig. 7 shows an example in which the CU (or gNB-CU) 231 manages the source DU 232-1 and the target DU 232-2. That is, Fig. 7 shows an example of handover by an intra-CU.

[0070] As shown in FIG. 7, in step S10, the UE 100 in the RRC idle state or the RRC inactive state executes a random access procedure to transition to an RRC connected state with respect to the network. The UE 100 executes an RRC setup to establish an RRC connection with the network during the execution of the random access procedure. Specifically, the UE 100 transmits an RRC setup request (RRCSetupRequest) message to the CU 231 via the source DU 232-1 as a message 3 (Msg3) in the random access procedure. Then, the CU 231 transmits an RRC setup (RRCSetup) message indicating permission to establish an RRC connection to the UE 100 as a message 4 (Msg4) in the random access procedure to the UE 100 via the source DU 232-1. The UE 100 also establishes an RRC connection with the network by the random access procedure.

[0071] In step S11, the UE 100 executes a registration procedure to register with the network. Specifically, the UE 100 transmits a registration request message, which is a NAS message, to the AMF 300 via the source DU 232-1 and the CU 231. Then, the UE 100 receives a registration accept message indicating an acceptance response to the registration request message from the AMF 300, thereby completing registration with the network.

[0072] In step S12, the UE 100 transmits a PDU Session Establishment Request message to start the execution of a PDU session establishment procedure for establishing a PDU session. Specifically, the UE 100 may transmit an RRC message including a PDU Session Establishment Request message to the source DU 232-1. The receiver 220 of the gNB 200 receives the RRC message and outputs the received RRC message to the source DU 232-1.

[0073] In step S13, the source DU 232-1 transfers the PDU session establishment request message transmitted from the UE 100 to the CU 231. Specifically, the source DU 232-1 may transmit an F1AP message including the PDU session establishment request message to the CU 231 in response to receiving an RRC message including the PDU session establishment request message.

[0074] In step S14, the CU 231 transfers the PDU session establishment request message transmitted from the UE 100 to the AMF 300. Specifically, in response to receiving an F1AP message including the PDU session establishment request message, the CU 231 transmits an N2 message including the PDU session establishment request message to the AMF 300. The AMF 300 receives the PDU session establishment request message. In response to receiving the PDU session establishment request message, the AMF 300 selects an SMF and requests the SMF to establish a PDU session to the UE 100. The AMF 300 receives a message including a result (permission or rejection) of the PDU session establishment request from the SMF. In the following, it is assumed that the AMF 300 receives a message indicating permission to establish a PDU session from the SMF.

[0075] In step S15, the AMF 300 transmits a PDU Session Establishment Accept message indicating an acceptance response to the PDU session establishment request message to the UE 100. The PDU session establishment accept message is an example of a NAS message. Specifically, the AMF 300 may transmit an N2 message including the PDU session establishment accept message to the gNB 200. The receiver 220 of the gNB 200 receives the N2 message.

[0076] In step S16, the CU 231 transfers the PDU session establishment permission message to the source DU 232-1. Specifically, in response to receiving the N2 message including the PDU session establishment permission message, the CU 231 may transmit an F1AP message including the PDU session establishment permission message to the source DU 232-1.

[0077] In step S17, the source DU 232-1 transfers a PDU session establishment permission message to the UE 100. Specifically, in response to receiving an F1AP message including the PDU session establishment permission message, the source DU 232-1 may transmit an RRC message (e.g., an RRC reconfiguration message) including the PDU session establishment permission message to the UE 100. The UE 100 receives the PDU session establishment permission message.

[0078] In step S18, the CU 231 associates the UE 100 with the network slice. Specifically, the CU 231 associates a UE identifier (user equipment identifier) ​​of the UE 100 with network slice information related to the network slice.

[0079] FIG. 8(A) is a diagram showing an example of an association between an identifier of UE 100 and network slice information.

[0080] First, the NSSAI may be used as the network slice information. Work As slice information, the SST included in the NSSAI may be used. As described later, the CU 231 can set communication characteristics permitted for the UE 100 from the SST. The CU 231 may acquire the SST, for example, as follows.

[0081] That is, UE 100 includes the NSSAI in a PDU session establishment request message and transmits it (step S12). When AMF 300 receives the PDU session establishment request message (step S14), it extracts the NSSAI included in the PDU session establishment request message and transmits an Nsmf message (Nsmf_PDUSession_CreateSMContextRequest) including the NSSAI to SMF, thereby requesting PDU session establishment from SMF. When the SMF permits the establishment of a PDU session, it transmits a Namf message (Namf_Communication_N1N2MessageTransfer) including a PDU session establishment permission message to AMF 300. At this time, the SMF transmits the permitted NSSAI included in the PDU session establishment permission message. AMF 300 The CU 231 may extract a PDU session establishment permission message from the Namf message and transmit the PDU session establishment permission message to the UE 100 (step S15). The CU 231 may extract the permitted NSSAI from the PDU session establishment permission message and set the NSSAI to the NSSAI shown in FIG. 8(A).

[0082] Secondly, the IP address of UE 100 may be used as the UE identifier of UE 100. CU 231 may obtain the IP address of UE 100, for example, as follows. That is, when the SMF permits the establishment of a PDU session, the SMF assigns an IP address to UE 100. The SMF transmits the IP address assigned to UE 100 as an authorized IP address in a PDU session establishment authorization message. CU 231 may extract the authorized IP address from the PDU session establishment authorization message received from AMF 300, and set the authorized IP address as the UE identifier shown in FIG. 8(A). That is, CU 231 may associate the NSSAI (the SST included in the NSSAI) with the IP address by extracting the NSSAI and the IP address from the PDU session establishment authorization message (step S15). CU 231 may store the associated UE identifier and SST in a memory.

[0083] Thirdly, when associating, the CU231 may set communication characteristics corresponding to the network slice information. For example, as shown in FIG. 8(A), since eMBB requires "high speed and large capacity", the communication characteristics may be set to require a frequency band wider than a certain band. Furthermore, since URLLC requires "ultra-low latency", the CU231 may set, for example, the communication characteristics to require a reception quality higher than a certain quality. Furthermore, in mMTC, Many Since "connection" is requested, CU231 may set, for example, a stable frequency band as the communication characteristic. In this way, CU231 may set communication characteristics corresponding to the SST based on the SST. Note that the communication characteristics shown in FIG. 8(A) are only an example, and other communication characteristics may be set. One example of other communication characteristics is "continue data communication", which prioritizes current data communication over measurement reports.

[0084] 7, in step S20, the UE 100 transmits a measurement report (Measurement Report) by satisfying the event trigger. The receiver 220 of the gNB 200 receives the measurement report and outputs the measurement report to the source DU 232-1.

[0085] In step S21, upon receiving the measurement report, the source DU 232-1 transmits an uplink RRC message transfer (UL RRC Message Transfer) message including the measurement report to the CU 231. The uplink RRC message transfer message is an example of an F1AP message.

[0086] In step S22, in response to receiving the measurement report, the CU 231 determines a threshold value used for determining whether or not to execute a handover.

[0087] First, when a second reception quality (i.e., "high reception quality") higher than the first reception quality is required as a communication characteristic, the CU231 may determine the threshold by changing the threshold (first threshold) to a higher threshold (second threshold). Specifically, when "high reception quality" is required, the CU231 may determine the threshold (e.g., threshold expressed in RSRP) to a value that is "-10 dBm" or higher than the first threshold (e.g., threshold expressed in RSRP).

[0088] Secondly, when a higher reception quality ("higher reception quality") than the second reception quality is required as a communication characteristic, the CU231 may determine the threshold by changing the preset first threshold to a third threshold higher than the second threshold. Specifically, when "higher reception quality" is required, the CU231 may determine the threshold (for example, the threshold expressed in RSRP) to be a value higher than the first threshold by "-20 dBm" or more.

[0089] Thirdly, when a frequency band with a fluctuation width smaller than the first fluctuation width (i.e., a "stable frequency band") is required as a communication characteristic, the CU231 may determine thresholds for an RSRP threshold for the RSRP and a SINR threshold for the SINR. Specifically, when a "stable frequency band" is required, the CU231 may set a preset threshold for the RSRP as the RSRP threshold and a value of "5 dBm" or more as the SINR threshold. In this case, the reception quality includes the RSRP and the SINR, and when the RSRP is equal to or greater than the RSRP threshold and the SINR is equal to or greater than the SINR threshold, it may be determined to execute a handover. By using the SINR threshold to determine whether or not to execute a handover, it is possible to handover the UE100 to a cell with less noise than a certain level (i.e., a cell capable of providing an mMTC service).

[0090] In this way, the CU 231 can determine the threshold value used to determine whether or not to execute a handover, based on the communication characteristics corresponding to the SST.

[0091] Note that the CU 231 may identify the communication characteristic corresponding to the UE identifier, as shown in FIG. 8(A), based on the IP address of the UE 100 included in the measurement report.

[0092] In step S23 (FIG. 9), the CU231 determines whether or not to execute a handover based on the reception quality included in the measurement report and the threshold determined in step S22. The CU231 may determine to execute a handover when the reception quality is equal to or higher than the threshold (or when the reception quality indicates a value higher than the threshold). On the other hand, the CU231 may determine not to execute a handover when the reception quality is less than the threshold (or when the reception quality is equal to or lower than the threshold). When the CU231 determines to execute a handover (YES in step S23), the process proceeds to step S24. On the other hand, when the CU231 does not determine to execute a handover (NO in step S23), the process proceeds to step S25.

[0093] In step S24, the CU 231 performs a process for executing handover. For example, the CU 231 transmits, to the UE 100, an RRC reconfiguration message including information for the UE 100 to access the target DU 232-2.

[0094] In step S25, the CU 231 determines timing information indicating timing for transmitting a measurement report from the next time onward based on the communication characteristics. The CU 231 transmits a message (second message) including the timing information to the UE 100. The CU 231 may determine the timing information, for example, as follows.

[0095] First, when "continuation of data communication" is requested as a communication characteristic, CU231 may determine timing information indicating a timing delayed from a set transmission timing for the next measurement report when UE100 is in data communication. By setting the timing delayed from the set timing information, data communication in UE100 can be prioritized over transmission of a measurement report.

[0096] Secondly, when "high reception quality" is requested as a communication characteristic, the CU 231 may determine timing information for setting the timing for transmitting the next measurement report at the timing when the UE 100 finds a cell with a second reception quality higher than the first reception quality. The UE 100 transmits the measurement report at the timing when the measurement result of the second reception quality is obtained, thereby enabling handover to a cell providing "high reception quality".

[0097] The CU 231 transmits, to the UE 100, measurement timing configuration information including the timing information.

[0098] Specifically, in step S25, the CU 231 Measurement timing setting information and generate an RRC reconfiguration message including the F1AP message, and transmit the RRC reconfiguration message to the source DU 232-1 through a UE Context Modification Request message. The UE Context Modification Request message is an example of an F1AP message and also an example of a second message.

[0099] 10A illustrates an example of an information element (IE) included in a UE context change request message according to the first embodiment. setting The information (RRC reconfiguration message including the information) may be included in the "CU to DU RRC information" shown in FIG. 10(A). FIG. 10(B) shows an example of information elements included in the "CU to DU RRC information". Measurement Timing settingThe information may be included in "Measurement Timing Configuration" in "CU to DU RRC information".

[0100] 9, in step S26, the source DU 232-1 extracts an RRC reconfiguration message from the UE context modification request message, and transmits the RRC reconfiguration message to the UE 100. The UE 100 receives the RRC reconfiguration message, and transmits the next measurement report according to the timing information included in the RRC reconfiguration message.

[0101] In this way, in the first embodiment, the CU 231 determines the threshold value used to determine whether or not to execute a handover based on the network slice information (e.g., SST). node (e.g., the receiver 220 of the gNB 200) receives a first message including network slice information regarding the network slice from a core network device (e.g., the AMF 300). node (e.g., the receiver 220 of the gNB 200) receives a measurement report from a user equipment (e.g., the UE 100). node (For example, the CU 231 of the gNB 200 (or the control unit 230 of the gNB 200)) determines a threshold value to be used for determining whether or not to execute a handover based on the network slice information in response to receiving the measurement report. Fourth, node (For example, the CU 231 of the gNB 200 (or the control unit 230 of the gNB 200)) value Based on the threshold value, it is determined whether or not to execute handover of the user equipment.

[0102] In this way, the gNB 200 can determine the threshold value used to determine whether or not to execute handover based on the network slice information, and therefore, for example, it is possible to handover the UE 100 to a cell that can provide a service represented by the service type. Therefore, the UE 100 can be handed over to the optimal cell according to the service type.

[0103] (Another operation example according to the first embodiment) In the first embodiment, an IP address has been described as an example of a UE identifier, but the UE identifier is not limited to this. The UE identifier may be, for example, a subscription permanent identifier (SUPI). In this case, the AMF 300 receives an encrypted subscription concealed identifier (SUCI) from the UE 100 during the registration procedure (step S11), and acquires the decrypted SUCI for the SUCI from a unified data management (UDM). The AMF 300 retains the SUPI in a memory or the like together with the NSSAI permitted to the UE 100 during the registration procedure. Then, when the retained NSSAI matches the NSSAI included in the message received from the SMF when the SMF permits the establishment of a PDU session, the AMF 300 transmits the retained NSSAI and SUPI to the CU 231. The CU 231 associates the received NSSAI and SUPI as shown in FIG. 8(A) (step S18). Then, the CU 231 identifies the communication characteristics required by the UE 100 based on the SUPI included in the measurement report (steps S20 and S21), and determines a threshold based on the communication characteristics (step S22).

[0104] [Second embodiment] Next, a second embodiment will be described, focusing on the differences from the first embodiment.

[0105] In the first embodiment, an example is described in which the CU231 determines a threshold value used to determine whether or not to execute a handover based on network slice information. In the second embodiment, an example is described in which the CU231 determines the threshold value based on service quality information representing service quality. Specifically, in the second embodiment, an example is described in which the CU231 sets communication characteristics based on service quality information included in a PDU session establishment permission message (step S15), and determines a threshold value used to determine whether or not to execute a handover based on the communication characteristics.

[0106] At the time of PDU session establishment (steps S12 to S17 in FIG. 11), the SMF performs processing to establish QoS flows between the UE 100 and the UPF. A QoS flow is the finest granularity of differentiating QoS within a PDU session. A QoS flow enables communication with a guaranteed certain QoS, such as bit rate and packet error rate. The SMF may establish one or more QoS flows within a PDU session.

[0107] Each QoS flow can be identified by a QoS Flow ID (QFI). Meanwhile, each QoS characteristic can be identified by a 5QI. The 5QI is an example of a QoS identifier that identifies a QoS characteristic.

[0108] FIG. 11 is a diagram illustrating an example of 5QI according to the first embodiment. The 5QI illustrated in FIG. 11 illustrates an example of 5QI described in 3GPP TS 23.501 V17.9.0 (2023-06). As illustrated in FIG. 11, the 5QI determines the packet delay budget and the packet error rate (P acIt is possible to uniquely determine QoS characteristics such as a QoS metric, such as a QoS metric, a QoS metric, and a QoS metric such as a metric error rate (Ket Error Rate). The packet delay budget indicates an upper limit of the time that a packet is delayed between the UE 100 and the UPF. When a UL packet transmitted from the UE 100 and a DL packet transmitted from the UPF arrive at the destination beyond the time indicated by the packet delay budget, the packet may be counted as a packet loss.

[0109] The service quality information such as 5QI and QFI is included in the PDU session establishment permission message (step S15 in FIG. 11). When the SMF establishes a QoS flow, it generates a PDU session establishment permission message including the service quality information (specifically, QoS Flow level parameters) and transmits a Namf message (Namf_Communication_N1N2MessageTransfer) including the PDU session establishment permission message to the AMF300. The AMF300 extracts the PDU session establishment permission message from the Namf message and transmits the PDU session establishment permission message to the CU231 (step S15 in FIG. 7). The CU231 can obtain the service quality information by extracting the service quality information from the PDU session establishment permission message. The PDU session establishment permission message is also an example of a first message, as in the first embodiment.

[0110] The CU 231 can set communication characteristics based on the quality of service information.

[0111] FIG. 8(B) is a diagram showing an example of communication characteristics according to the second embodiment. In the second embodiment, the communication characteristics are set using network slice information (e.g., SST) and service quality information. The example of FIG. 8(B) shows an example in which a packet delay budget and a packet error rate are used as the service quality information. That is, in FIG. 8(B), CU231 sets the communication characteristics based on the SST, the packet delay budget, and the packet error rate. Then, CU231 can determine a threshold value to be used for determining whether or not to execute a handover based on the communication characteristics.

[0112] (Operation example according to the second embodiment) Next, an operation example according to the second embodiment will be described.

[0113] Fig. 12 is a diagram showing an example of an operation according to the second embodiment. Fig. 12 shows an example of handover of an intra-CU, similar to the first embodiment (Fig. 11). In Fig. 12, the same processes as those in the first embodiment (Fig. 11) are denoted by the same reference numerals. Note that, in the following, a description of the same processes as those in the first embodiment (Fig. 11) will be omitted.

[0114] As shown in FIG. 12, in step S30, CU231 associates the UE identifier of UE100 with the service quality information. As in the first embodiment, the PDU session establishment permission message (step S15) includes the IP address of UE100 as an example of the UE identifier. The PDU session establishment permission message (step S15) also includes service quality information (e.g., 5QI). Furthermore, the PDU session establishment permission message (step S15) includes network slice information (e.g., SST) as described in the first embodiment. CU231 extracts the IP address, 5QI, and SST of UE100 from the PDU session establishment permission message (step S15), and associates the IP address, the 5QI, and the SST. The UE identifier shown in FIG. 8(B) represents an example of the IP address of UE100.

[0115] Then, the CU231 sets the communication characteristics in the same manner as in the first embodiment when associating. Regarding the setting of the communication characteristics, the CU231 may determine the communication characteristics based on the network slice information, determine the communication characteristics based on the service quality information, and determine the final communication characteristics based on the two communication characteristics. An example of the final communication characteristics is shown in FIG. 8(B).

[0116] In step S31, in response to receiving the measurement report from the UE 100, the CU 231 determines a threshold value used for determining whether or not to execute a handover based on the service quality information. Specifically, similar to the first embodiment, the CU 231 determines the threshold value based on the communication characteristics. The subsequent steps are the same as those in the first embodiment (FIG. 9). The CU 231 transmits timing information indicating the transmission timing of the measurement report to the UE 100 based on the communication characteristics (steps S25 and S26), similar to the first embodiment.

[0117] (Another operation example according to the second embodiment) In the second embodiment, an example has been described in which the CU231 determines the threshold value for determining whether or not to execute handover based on the network slice information and the service quality information. For example, the CU231 may determine the threshold value based on the service quality information without using the network slice information. In this case, the CU231 may determine the communication characteristics using the service quality information without using the network slice information (step S30).

[0118] First, node (e.g., the receiver 220 of the gNB 200) receives a first message (e.g., a PDU session establishment acceptance message) including at least one of network slice information regarding the network slice and service quality information representing the quality of the service from a core network device (e.g., the AMF 300). node receives a measurement report from a user equipment (e.g., UE 100). node(For example, the CU231 of the gNB200 (or the control unit 230 of the gNB200)) determines a threshold value to be used for determining whether or not to execute a handover based on at least one of the network slice information and the service quality information in response to receiving the measurement report. Fourth, node (For example, CU231 of gNB200 (or control unit 230 of gNB200)) determines whether or not to execute handover of the user equipment based on the reception quality indicating the reception quality included in the measurement report and a threshold value.

[0119] [Third embodiment] Next, a third embodiment will be described. In the third embodiment, differences from the first embodiment will be mainly described. In the second embodiment, an example was described in which the CU 231 determines a threshold value used to determine whether or not to execute a handover based on at least one of network slice information and service quality information. In the third embodiment, an example is described in which the threshold value is determined using at least one of the connection state of the UE 100 and statistical information related to past handovers of the UE 100.

[0120] That is, CU231 may determine the threshold value based on at least one of network slice information, service quality information, a connection state of a user equipment (e.g., UE100), and statistical information of past handovers of the user equipment.

[0121] The connection state of UE 100 includes, for example, a state in which UE 100 is performing data communication and a state in which UE 100 is not performing data communication. The threshold value used for determining whether or not to execute handover may be different between the state in which UE 100 is performing data communication and the state in which UE 100 is not performing data communication. In this case, CU 231 sets different communication characteristics between the state in which UE 100 is performing data communication and the state in which UE 100 is not performing data communication (step S18 or step S30). Then, in response to receiving the measurement report (steps S20 and S21), CU 231 checks the data packet between UE 100 and UPF and determines the threshold value based on the communication characteristics.

[0122] The CU231 holds, as past handover statistical information, for example, a threshold value when it is determined to execute a handover and a threshold value when it is determined not to execute a handover in a memory. The CU231 may set the threshold value when it is determined not to execute a handover to a higher threshold value than the threshold value when it is determined to execute a handover (step S22 or step S31). This makes it possible for the CU231 to easily hand over the UE100 to a cell to which it has previously determined to execute a handover, for example.

[0123] The CU231 may determine the threshold by combining any one of the connection state of the UE100 and past handover statistical information with the network slice information, or may determine the threshold by combining any one of the connection state of the UE100 and past handover statistical information with the service quality information. Alternatively, the CU231 may determine the threshold by combining the connection state of the UE100, past handover statistical information, network slice information, and service quality information.

[0124] [Other embodiments] In the first to third embodiments, an example of handover by intra-CU has been described, but the present invention is not limited thereto. The handover may be an inter-CU handover in which handover is performed between CUs. In this case, for example, in FIG. 7 and FIG. 9, the source DU 232-1 may be read as the source gNB (or the CU of the source gNB), and the target DU 232-2 may be read as the target gNB (or the CU of the target gNB). In this case, a PDU session establishment request message is transmitted from the source gNB 200-1 to the AMF 300 (step S14), and a PDU session establishment permission message is transmitted from the AMF 300 to the source gNB 200-1 (step S15). In addition, the association (step S18) and the handover decision (step S22) may be performed in the source gNB 200-1.

[0125] Also, a program may be provided that causes a computer to execute each operation and each process described in the first to third embodiments. The program may be recorded in a computer-readable medium of the gNB200. Using the computer-readable medium, it is possible to install the program in a computer. Here, the computer-readable medium on which the program is recorded may be a non-transient recording medium. The non-transient recording medium is not particularly limited, and may be, for example, a recording medium such as a CD-ROM or a DVD-ROM. Also, circuits that execute each operation and each process may be integrated, and a part of them may be configured as a semiconductor integrated circuit (chip set, SoC).

[0126] Although one embodiment has been described in detail above with reference to the drawings, the specific configuration is not limited to the above, and various design changes, etc. are possible within the scope of the gist. In addition, it is also possible to combine all or part of each embodiment, each operation, each process, and each step within the scope of not contradicting each other.

[0127] (Additional Note) (Appendix 1) A communication control method in a mobile communication system, comprising: A base station receives a first message from a core network device, the first message including at least one of network slice information regarding a network slice and service quality information representing a quality of service; receiving, by the base station, a measurement report from a user equipment; determining a threshold value used for determining whether or not to execute a handover based on at least one of the network slice information and the service quality information, in response to receiving the measurement report by the base station; The base station determines whether or not to execute handover of the user equipment based on a reception quality indicating a reception quality included in the measurement report and the threshold value. Communications control method.

[0128] (Appendix 2) The network slice information is a network slice identifier that identifies the network slice. 2. The communication control method according to claim 1.

[0129] (Appendix 3) The network slice information is service type information that is included in the network slice identifier and indicates a service type associated with the network slice. 3. The communication control method according to claim 1 or 2.

[0130] (Appendix 4) The service quality information is a QoS identifier that identifies a QoS characteristic. A communication control method according to any one of Supplementary Note 1 to Supplementary Note 3.

[0131] (Appendix 5) the first message includes a user equipment identifier that identifies the user equipment; The base station further comprises at least one of associating the user equipment identifier with the network slice information and associating the user equipment identifier with the quality of service information based on the first message. A communication control method according to any one of Supplementary Note 1 to Supplementary Note 4.

[0132] (Appendix 6) The determining step includes a step of determining the threshold value based on communication characteristics corresponding to at least one of the network slice information and the service quality information by the base station. A communication control method according to any one of Supplementary Note 1 to Supplementary Note 5.

[0133] (Appendix 7) The determining step includes a step of changing the threshold to a second threshold higher than the first threshold when a second reception quality higher than the first reception quality is requested as the communication characteristic by the base station. A communication control method according to any one of Supplementary Note 1 to Supplementary Note 6.

[0134] (Appendix 8) The determining step includes a step of determining, by the base station, an RSRP threshold related to RSRP and an SINR threshold related to SINR as the thresholds when a frequency band with a fluctuation range smaller than a first fluctuation range is required as the communication characteristic corresponding to the network slice. A communication control method according to any one of Supplementary Note 1 to Supplementary Note 7.

[0135] (Appendix 9) The base station transmits a second message to the user equipment, the second message including timing information indicating a timing for transmitting the measurement report based on the communication characteristic; receiving the second message by the user equipment; and the user equipment transmitting the measurement report according to the timing information. A communication control method according to any one of Supplementary Note 1 to Supplementary Note 8.

[0136] (Appendix 10) The determining step includes a step in which the base station determines the threshold value based on at least one of the network slice information, the service quality information, the connection state of the user equipment, and statistical information of past handovers of the user equipment. A communication control method according to any one of Supplementary Note 1 to Supplementary Note 9.

[0137] (Appendix 11) A base station capable of communicating with a user equipment and a core network device, A receiving unit that receives a first message including at least one of network slice information regarding a network slice and service quality information representing a quality of service from the core network device and receives a measurement report from the user equipment; A control unit that determines a threshold value to be used for handover determination based on at least one of the network slice information and the service quality information in response to receiving the measurement report, The control unit determines whether or not to execute handover of the user equipment based on a reception quality value indicating reception quality included in the measurement report and the threshold value. Base station. [Explanation of symbols]

[0138] 1: Mobile communication system 100: UE 110: Receiving section 120: Transmitting section 130: control unit 200: gNB (RAN) 210: Transmitter 220: Receiving unit 230: Control unit 231: CU 232: DU 250: Network communication unit 300: AMF 310: Receiver 320: Transmitter 330: Controller

Claims

1. A communication control method in a mobile communication system, comprising: A base station receives a first message from a core network device, the first message including at least one of network slice information regarding a network slice and service quality information representing a quality of service; receiving, by the base station, a measurement report from a user equipment; determining a threshold value used for determining whether or not to execute a handover based on at least one of the network slice information and the service quality information, in response to receiving the measurement report by the base station; The base station determines whether or not to execute handover of the user equipment based on a reception quality indicating a reception quality included in the measurement report and the threshold value. Communications control method.

2. The network slice information is a network slice identifier that identifies the network slice. The communication control method according to claim 1.

3. The network slice information is service type information that is included in the network slice identifier and indicates a service type associated with the network slice. The communication control method according to claim 2.

4. The service quality information is a QoS identifier that identifies a QoS characteristic. The communication control method according to claim 1.

5. The first message includes a user equipment identifier that identifies the user equipment; The base station may further include associating the user equipment identifier with the network slice information and / or associating the user equipment identifier with the quality of service information based on the first message. The communication control method according to claim 1.

6. The determining step includes a step of determining the threshold value based on communication characteristics corresponding to at least one of the network slice information and the service quality information by the base station. The communication control method according to claim 1.

7. The determining step includes a step of changing the threshold to a second threshold higher than the first threshold when a second reception quality higher than a first reception quality is requested as the communication characteristic by the base station. The communication control method according to claim 6.

8. The determining step includes a step of determining, by the base station, an RSRP threshold regarding RSRP and an SINR threshold regarding SINR as the thresholds when a frequency band having a fluctuation range smaller than a first fluctuation range is required as the communication characteristic corresponding to the network slice. The communication control method according to claim 6.

9. The base station transmits a second message to the user equipment, the second message including timing information indicating a timing for transmitting the measurement report based on the communication characteristic; receiving the second message by the user equipment; and the user equipment transmitting the measurement report according to the timing information. The communication control method according to claim 6.

10. The determining step includes a step in which the base station determines the threshold value based on at least one of the network slice information, the service quality information, the connection state of the user equipment, and statistical information of past handovers of the user equipment. The communication control method according to claim 1.

11. A base station capable of communicating with a user equipment and a core network device, A receiving unit that receives a first message including at least one of network slice information regarding a network slice and service quality information representing a quality of service from the core network device and receives a measurement report from the user equipment; A control unit that determines a threshold value to be used for handover determination based on at least one of the network slice information and the service quality information in response to receiving the measurement report, The control unit determines whether or not to execute handover of the user equipment based on a reception quality value indicating reception quality included in the measurement report and the threshold value. Base station.

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