Base station

Abstract

This base station comprises: a transmission unit that transmits, to another base station via a control device of a core network, an instruction for mobility in lower layer control; and a reception unit that receives, from the other base station via the control device, information relating to the state of transmission of a reference signal used to transition a terminal as the mobility.

Description

Base station 【0001】 This disclosure relates to a base station that executes Lower layer Triggered Mobility (LTM). 【0002】 The 3rd Generation Partnership Project (3GPP (registered trademark)) is standardizing the 5th generation mobile communication system (also called 5G, New Radio (NR) or Next Generation (NG)), and is also proceeding with the standardization of the next generation mobile communication system called Beyond 5G, 5G Evolution or 6G. 【0003】 In 3GPP Release 19, an extension of Lower layer Triggered Mobility (LTM) that triggers handover (HO) to transition a terminal to another cell in the lower layer (L1 / L2) is being discussed. Specifically, on the premise that a base station is composed of a plurality of distributed units (DUs) forming a cell and one central unit (CU) that controls the DUs, in addition to Intra-CU LTM that executes LTM between DUs under the same base station (CU), Inter-CU LTM that executes LTM between different base stations (CUs) is being discussed (Non-Patent Document 1). 【0004】 As a reference signal (RS) used for Intra-CU LTM, it is being considered not only to support periodic CSI-RS but also semi-persistent CSI-RS (SP CSI-RS) (Non-Patent Document 2). Note that CSI may also mean channel state information. 【0005】“New WID: NR mobility enhancements Phase 4”, RP-234036, 3GPP TSG RAN Meeting #102, 3GPP, December 11-15, 2023 “LS on the support of semi-persistent CSI-RS resource for LTM candidate cells”, R3-247006, 3GPP TSG RAN WG3 Meeting #126, 3GPP, November 18-22, 2024 【0006】 To execute Inter-CU LTM, it is necessary to send and receive information regarding the transmission status of RS signals, such as SP CSI-RS (e.g., transmission status), between the source base station from which the terminal transitions and the target base station to which the terminal transitions. The transmission status may indicate, for example, transmission, stopped, paused, resumed, active, or inactive. This information regarding the transmission status is sent and received via the interface connecting the base stations. 【0007】 However, in some areas where base stations were deployed, it was difficult to lay hardware such as optical fibers to create interfaces between base stations. Furthermore, in cases where the base stations crossed areas managed by the core network (CN) control unit, it was not even anticipated that interfaces connecting base stations would be provided. As a result, it was difficult to send and receive information regarding the transmission status of RS signals, such as SP CSI-RS, which is necessary for executing Inter-CU LTM, between the source base station from which the terminal transitions and the target base station to which the terminal transitions. 【0008】 Therefore, this disclosure aims to provide a base station that can support the transmission and reception of information regarding the transmission status of RS used in Inter-CU LTM, even when it is difficult or not anticipated to provide an interface connecting base stations. 【0009】One aspect of the disclosure is a base station comprising: a transmitting unit (radio signal transmitting / receiving unit 110) that transmits instructions for lower-layer control mobility to other base stations via a control device of the core network; and a receiving unit (radio signal transmitting / receiving unit 110) that receives information from the other base station via the control device regarding the transmission status of a reference signal used to transition a terminal as the mobility. 【0010】 Figure 1 is an overall schematic diagram of the wireless communication system. Figure 2 is a diagram showing the frequency range used in the wireless communication system. Figure 3 is a diagram showing an example of the configuration of wireless frames, subframes, slots, and symbols used in the wireless communication system. Figure 4 is a functional block diagram of a base station. Figure 5 is a functional block diagram of a terminal. Figure 6 is a diagram showing the sequence for sending and receiving the transmission status of SP CSI-RS in NG LTM. Figure 7 is a diagram showing the sequence for sending and receiving the transmission status of SP CSI-RS in NG LTM. Figure 8 is a diagram showing the sequence for sending and receiving the transmission status of SP CSI-RS in NG LTM. Figure 9 is a diagram showing an example of a MAC CE for activating / deactivating the SP CSI-RS resource set. Figure 10 is a diagram showing an example of a MAC CE for activating / deactivating the SP CSI-RS resource set. Figure 11 is a diagram showing an example of the hardware configuration of a base station and a terminal. Figure 12 is a diagram showing an example of the vehicle configuration. 【0011】 The embodiments will be described below with reference to the drawings. Note that identical or similar reference numerals are used to denote the same functions and components, and their descriptions will be omitted as appropriate. 【0012】 (1) Wireless communication system configuration The wireless communication system 10 shown in Diagram 1 is a wireless communication system that follows a method called 5G. On the other hand, wireless communication system 10 may also be a wireless communication system that follows a method called Beyond 5G, 5G Evolution, or 6G. 【0013】The wireless communication system 10 can support Massive Multiple-Input Multiple-Output (Massive MIMO), which generates a more directional beam by controlling the wireless signals transmitted from multiple antenna elements; carrier aggregation (CA), which uses multiple component carriers (CCs) bundled together; and dual connectivity (DC), which enables simultaneous communication with two base stations. 【0014】 As shown in Figure 1, the wireless communication system 10 includes a base station (hereinafter also referred to as gNB) 100 that constitutes the Next Generation-Radio Access Network (NG-RAN) 20, and a terminal (hereinafter also referred to as user equipment (UE)) 200 that communicates wirelessly with the gNB 100. NG-RAN 20 may be read as gNB 100. 【0015】 NG-RAN20 is connected to the core network (CN) 30. CN30 consists of multiple network functions (NFs). These NFs include, for example, the Access and Mobility Management Function (AMF) 300 and the Network Data Analytics Function (NWDAF) 400. The AMF 300 registers the UE200 and manages the mobility of the UE200. The NWDAF 400 optimizes CN30. Note that the specific configuration of the wireless communication system 10, such as the number of gNB100s and UE200s, is not limited to the example shown in Figure 1. Furthermore, NG-RAN20 and CN30 may simply be referred to as the "network (NW)". 【0016】 The gNB100 may consist of distributed units (DUs) that form cells to which the UE200 is connected, and a central unit (CU) that controls the DUs. The CU may consist of a CU-CP that controls the control plane (CP) and a CU-UP that controls the user plane (UP). In other words, the gNB100 may consist of DUs, CU-CPs, and CU-UPs. 【0017】The gNB100 can perform a handover (HO) to move the UE200 to another cell. The gNB100 can also perform Lower Layer Triggered Mobility (LTM), which triggers HO at lower layers (L1 / L2). For LTM execution, the UE200 measures cell quality and sends the measurement results to the gNB100 as a measurement report. Based on these measurement results, configuration information (LTM config), including information about potential candidate cells to which the UE200 may transition, is sent and received between the gNB100s and then configured on the UE200. This sequence will be described in detail in the operation example. 【0018】 An LTM that transitions the UE200 between multiple DUs (cells formed by them) controlled by the same gNB100 (CU) may be called an Intra-CU LTM. Similarly, an LTM that transitions the UE200 between cells controlled by different gNB100s (CU) may be called an Inter-CU LTM. An Inter-CU LTM may also be called an NG LTM if the gNB100s are not connected via an Xn interface. The operation examples provided here primarily describe the NG LTM. 【0019】 As shown in Figure 2, the wireless communication system 10 may support multiple frequency ranges (FRs). Specifically, it may support the following FRs: • FR1: 410 MHz to 7.125 GHz • FR2-1: 24.25 GHz to 52.6 GHz • FR2-2: Over 52.6 GHz to 71 GHz 【0020】 In FR1, a subcarrier spacing (SCS) of 15, 30, or 60 kHz and a bandwidth (BW) of 5 to 100 MHz may be used. In FR2-1, an SCS of 60 or 120 kHz (or 240 kHz) and a BW of 50 to 400 MHz may be used. 【0021】In FR2-2, to avoid an increase in phase noise, Cyclic Prefix-Orthogonal Frequency Division Multiplexing (CP-OFDM) or Discrete Fourier Transform-Spread-Orthogonal Frequency Division Multiplexing (DFT-S-OFDM) with a larger SCS may be used. 【0022】 As shown in Figure 3, one slot in the wireless communication system 10 consists of 14 symbols. If this configuration is maintained, the larger (wider) the SCS becomes, the shorter the symbol period (and slot period). Note that the SCS is not limited to the frequencies shown in Figure 3, and may be other frequencies such as 480 kHz or 960 kHz. 【0023】 Furthermore, the number of symbols constituting one slot does not necessarily have to be 14; for example, it could be 28 or 56 symbols. In addition, the number of slots per subframe may vary depending on the SCS. 【0024】 (2) Functional block configuration of the wireless communication system (2.1) Functional block configuration of the base station As shown in Figure 4, the gNB100 includes a wireless signal transmitting / receiving unit 110, an amplifier unit 120, a modulation / demodulation unit 130, a control signal / reference signal processing unit 140, an encoding / decoding unit 150, a data transmitting / receiving unit 160, and a control unit 170. 【0025】 In this embodiment, gNB100 may be interpreted as a source base station (gNB) 100A that controls the cell from which UE200 transitions, or as a target base station (gNB) 100B that controls the cell to which UE200 transitions, in the HO or LTM described above. Note that HO may be understood as a higher-level concept than LTM. 【0026】The wireless signal transceiver 110 transmits and receives wireless signals to and from the UE 200. The wireless signal transceiver 110 may consist of a transmitting unit that transmits wireless signals to the UE 200 and a receiving unit that receives wireless signals from the UE 200. The wireless signal may include data, or may be interpreted as data. Transmission may be interpreted as setting, instruction, notification, etc. Reception may be interpreted as reporting, notifying, etc. Settings may be implemented by setting information (information elements (IE)) of the Wireless Resource Control (RRC) layer, and instructions may be implemented by control elements (CE) or downlink control information (DCI) of the Media Access Control (MAC) layer. 【0027】 Furthermore, the wireless signal transmission / reception unit 110 can transmit and receive information as described in the operation example. 【0028】 The wireless signal transceiver 110 of this embodiment can transmit lower-layer control mobility instructions to another gNB100 (here, referred to as gNB100B) via the control device of CN30. In other words, the wireless signal transceiver 110 of this embodiment can receive lower-layer control mobility instructions from another gNB100 (here, referred to as gNB100A) via the control device of CN30. 【0029】 The wireless signal transceiver 110 of this embodiment can receive information regarding the transmission status of a reference signal used for lower-layer control mobility (e.g., transmission status) from another gNB100 (here, referred to as gNB100B) via the control device of CN30. In other words, the wireless signal transceiver 110 of this embodiment can transmit the transmission status of a reference signal used for lower-layer control mobility to another gNB100 (here, referred to as gNB100A) via the control device of CN30. 【0030】The control unit of CN30 may be, for example, the AMF300 described above. Alternatively, the control unit of CN30 may be an NF that manages the mobility of UE200. For example, in a 6G CN30, if the AMF300 is divided into an NF that registers UE200 and an NF that manages the mobility of UE200, the control unit of CN30 may be the latter NF. 【0031】 The lower layer may mean L1 or L2. That is, the lower layer may be understood as a layer lower than the conventional L3 (RRC layer) that controls the HO. Mobility may mean the (cell) transition of the UE200. That is, the mobility of the lower layer control may mean the LTM described above, or it may mean causing the UE200 to transition as an LTM. Mobility may also mean sending and receiving information related to the LTM, such as the cell history of the UE200 and the position information of the UE200, and control (execution / cancellation of transitions) based on this information. 【0032】 The transition of UE200 as mobility may be interpreted as HO or LTM. That is, the transition of UE200 as mobility may be interpreted as a change in the cell (or beam) to which UE200 is connected. Alternatively, the transition of UE200 as mobility may be interpreted as control by gNB100 to change the cell (or beam) to which UE200 is connected. Note that the cell (or beam) to which UE200 is connected may mean the cell (or beam) where UE200 in the RRC_CONNECTED state resides. 【0033】The transition of UE200 as mobility may mean the entire HO or LTM sequence, or part of the HO or LTM sequence. For example, the transition of UE200 as mobility may mean that after receiving a measurement report from UE200, gNB100 sets candidate cells that could be the transition destination for UE200 (e.g., sending an LTM config). Alternatively, the transition of UE200 as mobility may mean that after receiving an L1 measurement report from UE200, gNB100 sends a cell switch command to UE200. These sequences will be explained in the operation examples below. 【0034】 The mobility instructions for lower-layer control may be interpreted as corresponding to the LTM indicator in the example operation, or as corresponding to the information contained in the HO require message or HO request message in the example operation. 【0035】 The transmission status of the reference signal used for lower-layer control mobility may be understood as the transmission status of the RS used by the UE200 to perform L1 measurement when executing LTM. Furthermore, this RS may be a reference signal transmitted using semi-persistent scheduling. This reference signal is, for example, a channel state information reference signal (CSI-RS), but is not limited to this. A CSI-RS transmitted using semi-persistent scheduling is also called a semi-persistent channel state information reference signal (SP CSI-RS). The wireless signal transceiver 110 of this embodiment may transmit the RS using semi-persistent scheduling. 【0036】Furthermore, RS transmitted by semi-persistent scheduling may be transmitted at predetermined intervals based on setting information (e.g., period, offset, time / frequency resource information) from higher-layer signaling (e.g., RRC signaling), and this transmission may be triggered by lower-layer signaling (e.g., media access control layer control elements (MAC CE) or downlink control information (DCI)). In other words, even if there is setting information from higher-layer signaling, RS transmitted by semi-persistent scheduling will not be transmitted unless triggered by lower-layer signaling, and the transmission status will be notified between gNB100s. In contrast, RS transmitted by persistent scheduling such as Periodic channel state information reference signal (P-CSI-RS) may be transmitted at predetermined intervals based on setting information from higher-layer signaling (e.g., RRC signaling). 【0037】 The wireless signal transceiver 110 of the embodiment may receive a message from the control device of CN30 regarding instructions for lower-layer control mobility. Furthermore, the information regarding the transmission status described above may be included in this message. This message may be understood to correspond to the HO command in the operation example. 【0038】 The wireless signal transceiver 110 of this embodiment may, via the control device of CN30, send an update message to another gNB100 (here, referred to as gNB100B) requesting an update of the lower-layer control mobility configuration information. In other words, the wireless signal transceiver 110 of this embodiment may, via the control device of CN30, receive an update message from another gNB100 (here, referred to as gNB100A) requesting an update of the lower-layer control mobility configuration information. The lower-layer control mobility configuration information may be understood to correspond to the LTM config in the operation example. The update message may be understood to correspond to the LTM config update message in the operation example. 【0039】The wireless signal transceiver 110 of this embodiment may receive an permission message for the update message described above from another gNB100 (here, referred to as gNB100B) via the control device of CN30. In other words, the wireless signal transceiver 110 of this embodiment may transmit an permission message for the update message described above to another gNB100 (here, referred to as gNB100A) via the control device of CN30. Furthermore, information regarding the transmission status described above may be included in the permission message. The permission message may be understood to correspond to the LTM config update Ack message in the operation example. 【0040】 The wireless signal transmitting / receiving unit 110 of the embodiment may receive the above-mentioned update message from another gNB100 (here, referred to as gNB100B) via the control device of CN30. In other words, the wireless signal transmitting / receiving unit 110 of the embodiment may transmit the above-mentioned update message to another gNB100 (here, referred to as gNB100A) via the control device of CN30. Furthermore, the above-mentioned information regarding the transmission status may be included in the update message. The update message may be understood to correspond to the LTM config update message in the operation example. 【0041】 The wireless signal transceiver 110 of the embodiment may transmit a media access control layer control element (MAC CE) to the UE200. The MAC CE may include RS resource information that the UE200 uses to perform L1 measurement. The RS resource information may be, for example, an RS resource ID. 【0042】 The amplifier section 120 consists of a Power Amplifier (PA) and a Low Noise Amplifier (LNA), among other components. The amplifier section 120 amplifies the wireless signal output from the wireless signal transmission / reception unit 110. The amplifier section 120 also amplifies the wireless signal output from the modulation / demodulation unit 130. 【0043】The modulation / demodulation unit 130 performs data modulation / demodulation, transmission power setting, resource block allocation, etc. for each predetermined communication destination (UE200 or another UE200). In the modulation / demodulation unit 130, CP-OFDM / DFT-S-OFDM may be applied. Also, DFT-S-OFDM may be used not only for the uplink (UL) but also for the downlink (DL). 【0044】 The control signal / reference signal processing unit 140 performs processing related to control signals transmitted and received between the UE200, for example, radio resource control (RRC) signaling. 【0045】 The control signal / reference signal processing unit 140 performs processing related to reference signals transmitted and received between the UE200, for example, Demodulation Reference Signal (DMRS), Phase Tracking Reference Signal (PTRS), Channel State Information-Reference Signal (CSI-RS), Sounding Reference Signal (SRS), Positioning Reference Signal (PRS). 【0046】 Note that the channels include a control channel and a data channel. The control channel includes a physical uplink control channel (PUCCH), a physical downlink control channel (PDCCH), a physical random access channel (PRACH), a physical broadcast channel (PBCH), etc. The data channel includes a physical uplink shared channel (PUSCH), a physical downlink shared channel (PDSCH), etc. 【0047】 The encoding / decoding unit 150 performs splitting / concatenation and coding / decoding of data included in radio signals for each predetermined communication destination (UE200 or another UE200). 【0048】Specifically, the encoding / decoding unit 150 decodes the data output from the modulation / demodulation unit 130 and concatenates the decoded data. Also, the encoding / decoding unit 150 divides the data output from the data transmission / reception unit 160 into a predetermined size and performs coding on the divided data. 【0049】 The data transmission / reception unit 160 performs operations such as assembly / disassembly of data units (Protocol Data Unit (PDU) / Service Data Unit (SDU)) that constitute data between each layer. The plurality of layers include a Media Access Control (MAC) layer, a Radio Link Control (RLC) layer, a Packet Data Convergence Protocol (PDCP) layer, and the like. Also, the data transmission / reception unit 160 performs error correction and retransmission control of data based on Hybrid Automatic Repeat Request (HARQ). 【0050】 The control unit 170 controls the gNB 100. The control unit 170 controls, for example, the transmission / reception of radio signals by the radio signal transmission / reception unit 110, the amplification by the amplifier unit 120, the data modulation / demodulation by the modulation / demodulation unit 130, the signal processing by the control signal / reference signal processing unit 140, the coding / decoding by the encoding / decoding unit 150, and the assembly / disassembly of data units by the data transmission / reception unit 160. 【0051】 The control unit 170 of the embodiment can perform the transition of the UE 200 between cells controlled by the gNB 100. That is, the control unit 170 of the embodiment can perform HO or perform lower layer control mobility (LTM). Note that HO and LTM may be read as terms such as cell transition, cell change, beam change, and the like. 【0052】The control unit 170 of the embodiment can execute LTM based on the LTM configuration information (LTM config) described in the operation example. That is, the control unit 170 of the embodiment can execute a transition of UE200 as LTM based on the LTM configuration information. Furthermore, the control unit 170 of the embodiment can anticipate the operation of other gNB100s. For example, the control unit 170 of the embodiment can anticipate that the control unit 170 of another gNB100 executes a transition of UE200 as LTM based on the LTM configuration information. 【0053】 (2.2) As shown in the terminal's functional block configuration diagram 5, the UE200 includes a wireless signal transmission / reception unit 210 and a control unit 220. 【0054】 The wireless signal transceiver 210 transmits and receives wireless signals to and from the gNB 100. The wireless signal transceiver 210 may consist of a transmitting unit that transmits wireless signals to the gNB 100 and a receiving unit that receives wireless signals from the gNB 100. The wireless signal may include data or may be interpreted as data. Transmission may be interpreted as reporting, notifying, etc. Reception may be interpreted as setting, instructing, notifying, etc. Setting may be implemented by setting information (information element (IE)) of the wireless resource control (RRC) layer, and instruction may be implemented by control element (CE) or downlink control information (DCI) of the media access control (MAC) layer. 【0055】 The wireless signal transmitting / receiving unit 210 can receive information transmitted by the wireless signal transmitting / receiving unit 110 described above. Furthermore, the wireless signal transmitting / receiving unit 210 can transmit information received by the wireless signal transmitting / receiving unit 110. Additionally, the wireless signal transmitting / receiving unit 210 can transmit and receive information as described in the operation example. 【0056】 The control unit 220 controls the UE200. The control unit 220 controls, for example, the transmission and reception of wireless signals by the wireless signal transmission / reception unit 210. 【0057】(3) Operation of the wireless communication system (3.1) Challenges Depending on the area in which the base stations are deployed, it was sometimes difficult to lay hardware such as optical fibers to realize the interface (Xn interface) connecting the base stations. For example, in mountainous areas, the construction and maintenance of optical fibers was difficult from a technical or cost perspective. In addition, there were cases where it was not anticipated to provide an Xn interface in the first place, such as when crossing the area under the jurisdiction of the Core Network (CN) control unit (AMF). For example, when crossing prefectural borders, it was not anticipated to provide an Xn interface in the first place. As a result, it was also difficult to send and receive information regarding the transmission status of RS such as SP CSI-RS, which is necessary for executing Inter-CU LTM, between the source base station from which the terminal transitions and the target base station to which the terminal transitions. 【0058】 (3.2) Examples of Operation Examples of the Embodiments will be described with reference to Figures 6 to 10. In the examples of operation, gNB100A is a Source gNB that controls the cell from which UE200 transitions, and gNB100B is a Target gNB that controls the cell to which UE200 transitions. 【0059】 Incidentally, LTM between gNB100s that do not have an Xn interface can be called NG LTM, since the information necessary for LTM is sent and received between gNB100s via CN30. This is named after the NG interface that connects CN30 and gNB100. Figures 6 to 8 are part of the sequence diagram for such NG LTM. Specifically, Figures 6 to 8 show the sequence in which gNB100A sends and receives information regarding the transmission status of RS used by UE200 to perform L1 measurement when executing LTM on UE200. In the specific operation example described below, this information regarding the transmission status of RS may be the transmission status of SP CSI-RS. 【0060】(3.2.1) Example of Operation 1 As shown in Figure 6, when gNB100A receives a measurement report from UE200 (step S01), it sends an HO required message to AMF300 requesting a transition of UE200, taking into account the cell quality included in the measurement report (e.g., Reference Signal Received Power (RSRP), Reference Signal Received Quality (RSRQ), Signal to Interference plus Noise Ratio (SINR)) (step S02). The HO required message includes information such as an LTM indicator that indicates the LTM of UE200. For example, the HO required message may include not only the LTM indicator but also the reference config, CSI-RS resource config, LTM Configuration ID Mapping List, and Early Sync Information Request (Request for RACH Configuration, LTM gNB-DU ID list). Note that this information may also be included in the Source NG-RAN to Target NG-RAN Node Transparent Container within the HO required message. 【0061】 The AMF300 forwards the information contained in the received HO required message to the gNB100B, including it in the HO request message (step S03). The forwarded information may also be included in the Source NG-RAN to Target NG-RAN Node Transparent Container within the HO request message. 【0062】If gNB100B approves the UE200 transition request contained in the received HO request message, it sends an HO request Ack message to AMF300 (step S04). The HO required Ack message contains information such as LTM configuration information (LTM config) which includes information about candidate cells that UE200 may transition to. For example, the HO required Ack message may include not only the LTM config, but also SSB information, reference config, Complete Candidate Configuration Indicator, LTM CFRA Resource Configuration, and LTM CFRA Resource Configuration for SUL. 【0063】 Furthermore, the HO required Ack message includes the transmission status of the SP CSI-RS that the UE200 uses to perform the L1 measurement. The transmission status may indicate, for example, transmission, stopped, paused, resumed, active, or inactive. 【0064】 This information may also be included in the Target NG-RAN Node to Source NG-RAN Node Transparent Container within the HO required Ack message. 【0065】 The AMF300 forwards the information contained in the received HO required Ack message to the gNB100A, including it in the HO command (step S05). The forwarded information may also be included in the Target NG-RAN Node to Source NG-RAN Node Transparent Container within the HO command. 【0066】Upon receiving an HO command, gNB100A sends a MAC CE to UE200 to activate / deactivate the SP CSI-RS resource set described above (step S06). This MAC CE allows UE200 to recognize the SP CSI-RS for performing L1 measurement. In addition to this MAC CE, gNB100A may also send an RRCReconfiguration message to UE200. This RRCReconfiguration message may include all or part of the LTM config described above. 【0067】 Although not shown in the diagram, the subsequent sequence is as follows: UE200 performs an L1 measurement using the SP CSI-RS mentioned above and sends an L1 measurement report to gNB100A. Upon receiving the L1 measurement report, gNB100A sends a cell switch command to UE200. This triggers the UE200's LTM (Long-Term Management). 【0068】 (3.2.2) Operation Example 2 Operation Example 2 is a sequence for updating the LTM configuration information (LTM config) described in Operation Example 1. 【0069】 As shown in Figure 7, gNB100A sends an LTM config update message to AMF300 requesting an update to the LTM config (step S11). The LTM config update message contains information such as the new LTM config. AMF300 forwards the received LTM config update message to gNB100B (step S12). 【0070】If gNB100B approves the request to update the LTM config contained in the received LTM config update message, it sends an LTM config update Ack message to AMF300 (step S13). AMF300 forwards the received LTM config update Ack message to gNB100A (step S14). 【0071】 The LTM config update Ack message contains information such as the transmission status of the SP CSI-RS used by the UE200 to perform L1 measurement. The transmission status may indicate, for example, transmission, stopped, paused, resumed, active, or inactive. This information may also be included in the Target NG-RAN Node to Source NG-RAN Node Transparent Container within the LTM config update Ack message. 【0072】 When gNB100A receives an LTM config update Ack message, it sends a MAC CE to UE200 to activate / deactivate the SP CSI-RS resource set described above (step S15). This MAC CE allows UE200 to recognize the SP CSI-RS for performing L1 measurement. In addition to this MAC CE, gNB100A may also send an RRCReconfiguration message to UE200. The RRCReconfiguration message may contain all or part of the updated LTM config. 【0073】 (3.2.3) Operation Example 3 Operation Example 3 is a sequence for updating the LTM configuration information (LTM config) as described in Operation Example 1, but unlike Operation Example 2, the target base station (gNB100B) triggers the LTM config update. 【0074】As shown in Figure 8, gNB100B sends an LTM config update message to AMF300 requesting an update to the LTM config (step S21). The LTM config update message contains information such as the new LTM config. Furthermore, the LTM config update message contains information such as the transmission status of the SP CSI-RS used by UE200 to perform L1 measurement. The transmission status may indicate, for example, transmission, stopped, paused, resumed, active, or inactive. AMF300 forwards the received LTM config update message to gNB100A (step S22). Note that this information may also be included in the Target NG-RAN Node to Source NG-RAN Node Transparent Container within the LTM config update message. 【0075】 If gNB100A approves the request to update the LTM config contained in the received LTM config update message, it sends an LTM config update Ack message to AMF300 (step S23). AMF300 forwards the received LTM config update Ack message to gNB100B (step S24). 【0076】 When gNB100A sends an LTM config update Ack message, it sends a MAC CE to UE200 to activate / deactivate the SP CSI-RS resource set described above (step S25). This MAC CE allows UE200 to recognize the SP CSI-RS for performing L1 measurement. In addition to this MAC CE, gNB100A may also send an RRCReconfiguration message to UE200. The RRCReconfiguration message may contain all or part of the updated LTM config. 【0077】 (3.2.4) MAC CE for SP CSI-RS resource set activation / deactivation The MAC CE described in operation examples 1 to 3 will be explained with reference to Figures 9 and 10. This MAC CE can activate / deactivate the SP CSI-RS resource set that the UE200 uses to perform L1 measurement. 【0078】 Figure 9 shows an example of a MAC CE indicating the activation / deactivation of the SP CSI-RS resource set for a single candidate cell. In the figure, "A / D" is a field that indicates the activation / deactivation status of the SP CSI-RS resource for a single candidate cell. For example, setting "A / D" to 1 may indicate an "active state," and setting "A / D" to anything else may indicate an "inactive state." The reverse is also possible. 【0079】 Figure 10 shows an example of a MAC CE that indicates the activation / deactivation of the SP CSI-RS resource set for multiple candidate cells. In the figure, "A / D" is a field that indicates the activation / deactivation status for the SP CSI-RS resource of each candidate cell. For example, if "A / D" is set to 1, it may indicate an "active state," and if "A / D" is set to anything else, it may indicate an "inactive state." The reverse is also possible. 【0080】 Furthermore, the MAC CE described in operation examples 1 to 3 may be used not only in NG LTM, but also in Intra-CU LTM and Inter-CU LTM using the Xn interface. 【0081】 (4) Operation and Effects According to the embodiment described above, even between gNB100s that are not provided with an Xn interface, information regarding the transmission status of RS (especially SR CSI-RS) used for Inter-CU LTM (e.g., transmission status) can be sent and received between the CN30 (AMF300) and the gNB100 via the NG interface. 【0082】 According to the embodiment described above, the transmission status of RS (in particular SR CSI-RS) used in Inter-CU LTM can be included in various messages in Inter-CU LTM. 【0083】 According to the embodiment described above, resource information for the RS (in particular, SR CSI-RS) used in Inter-CU LTM can be notified to the UE200 via the new MAC CE. 【0084】 (5) Other Embodiments Although the contents of the present invention have been described above in accordance with the embodiments, it will be obvious to those skilled in the art that the present invention is not limited to these descriptions and that various modifications and improvements are possible. 【0085】 In the embodiment described above, information transmission and reception between gNB100s is performed by one AMF300, but this is not limited to this. For example, if the CN30 (AMF300) to which gNB100A is connected and the CN30 (AMF300) to which gNB100B is connected are different, information transmission and reception between gNB100s may be performed by these two AMF300s. In this case, the two CN30s may be connected to each other via an interface that enables the transmission and reception of information necessary for the UE200's LTM. 【0086】 In the embodiments described above, the term "candidate cell" was used to mean "a cell that is a candidate for the target cell (the cell to which UE200 transitions)," but it may be replaced with "target cell" as long as it does not create a contradiction. Alternatively, "candidate cell" may be replaced with "LTM candidate cell." 【0087】 The examples of operation described above may be combined and applied in combination, as long as no inconsistencies arise. 【0088】The block diagrams used in the description of the above embodiments show functional units. These functional blocks (components) are realized by any combination of at least one of hardware and software. Furthermore, the method of realizing each functional block is not particularly limited. That is, each functional block may be realized using one device that is physically or logically coupled, or it may be realized using two or more physically or logically separated devices that are directly or indirectly connected (for example, using wired or wireless connections). A functional block may also be realized by combining software with the one or more of the above devices. 【0089】 Functions include, but are not limited to, judgment, decision, judgment, calculation, calculation, processing, derivation, investigation, exploration, confirmation, reception, transmission, output, access, resolution, selection, selection, establishment, comparison, assumption, expectation, assumption, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating (mapping), and assigning. For example, a functional block (configuration part) that enables transmission is called a transmitting unit or transmitter. In all cases, as mentioned above, the method of implementation is not particularly limited. 【0090】 For example, the base station 100 and terminal 200 in one embodiment of the present disclosure may function as computers that process the wireless communication method of the present disclosure. Figure 11 is a diagram showing an example of the hardware configuration of the base station 100 and terminal 200 according to one embodiment of the present disclosure. The above-mentioned base station 100 and terminal 200 may be physically configured as computer devices including a processor 1001, memory 1002, storage 1003, communication device 1004, input device 1005, output device 1006, bus 1007, etc. 【0091】In the following explanation, the term "device" can be replaced with "circuit," "device," "unit," etc. The hardware configuration of the base station 100 and terminal 200 may include one or more of the devices shown in the figure, or it may be configured to omit some of the devices. 【0092】 Each function in the base station 100 and terminal 200 is realized by loading predetermined software (programs) onto hardware such as the processor 1001 and memory 1002, which allows the processor 1001 to perform calculations, control communication by the communication device 1004, and control at least one of the reading and writing of data in the memory 1002 and storage 1003. 【0093】 The processor 1001 controls the entire computer, for example, by running an operating system. The processor 1001 may consist of a central processing unit (CPU) that includes interfaces with peripheral devices, control units, arithmetic units, registers, and so on. 【0094】 Furthermore, the processor 1001 reads programs (program code), software modules, data, etc., from at least one of the storage 1003 and the communication device 1004 into the memory 1002 and executes various processes accordingly. The program used is one that causes the computer to execute at least a part of the operations described in the above embodiment. Furthermore, although it has been explained that the above processes are executed by one processor 1001, they may be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. The program may also be transmitted from a network via a telecommunications line. 【0095】Memory 1002 is a computer-readable recording medium and may consist of at least one of the following: Read Only Memory (ROM), Erasable Programmable ROM (EPROM), Electrically Erasable Programmable ROM (EEPROM), Random Access Memory (RAM), etc. Memory 1002 may also be called a register, cache, main memory, etc. Memory 1002 can store executable programs (program code), software modules, etc., for carrying out a wireless communication method according to one embodiment of the present disclosure. 【0096】 The storage 1003 is a computer-readable recording medium and may consist of at least one of the following: an optical disc such as a Compact Disc ROM (CD-ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., Compact Disc, Digital Multipurpose Disc, Blu-ray® Disc), a smart card, flash memory (e.g., a card, stick, key drive), a floppy® disk, a magnetic strip, etc. The storage 1003 may also be called an auxiliary storage device. The above-mentioned storage medium may be, for example, a database, server, or other suitable medium including at least one of memory 1002 and storage 1003. 【0097】 The communication device 1004 is hardware (transceiver / receiver device) for communicating between computers via at least one of a wired network and a wireless network, and is also referred to as a network device, network controller, network card, communication module, etc. The communication device 1004 may be configured to include, for example, a high-frequency switch, duplexer, filter, frequency synthesizer, etc., in order to implement at least one of frequency division duplex (FDD) and time division duplex (TDD). 【0098】The input device 1005 is an input device that accepts input from an external source (e.g., a keyboard, mouse, microphone, switch, button, sensor, etc.). The output device 1006 is an output device that outputs to an external source (e.g., a display, speaker, LED lamp, etc.). The input device 1005 and the output device 1006 may be configured as an integrated unit (e.g., a touch panel). 【0099】 Furthermore, each device, such as the processor 1001 and memory 1002, is connected by a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or different buses may be configured for each device. 【0100】 Furthermore, the base station 100 and terminal 200 may be configured to include hardware such as a microprocessor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a programmable logic device (PLD), and a field programmable gate array (FPGA), and some or all of each functional block may be realized by such hardware. For example, the processor 1001 may be implemented using at least one of these hardware components. 【0101】Information notification is not limited to the embodiments described herein and may be carried out by other means. For example, information notification may be carried out by physical layer signaling (e.g., Downlink Control Information (DCI), Uplink Control Information (UCI)), upper layer signaling (e.g., Radio Resource Control (RRC) signaling, Medium Access Control (MAC) signaling), broadcast information (Master Information Block (MIB), System Information Block (SIB)), other signals, or combinations thereof. RRC signaling may also be called RRC messages, and may be, for example, RRC Connection Setup messages, RRC Connection Reconfiguration messages, etc. 【0102】Each aspect / embodiment described herein may apply to systems utilizing Long Term Evolution (LTE), LTE-Advanced (LTE-A), SUPER 3G, IMT-Advanced, 4th generation mobile communication system (4G), 5th generation mobile communication system (5G), 6th generation mobile communication system (6G), xth generation mobile communication system (xG) (where x is, for example, an integer or decimal), Future Radio Access (FRA), New Radio (NR), New radio access (NX), Future generation radio access (FX), W-CDMA®, GSM®, CDMA2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi®), IEEE 802.16 (WiMAX®), IEEE 802.20, Ultra-WideBand (UWB), Bluetooth®, and other appropriate systems, as well as at least one of the next-generation systems that are extended, modified, created, or defined based thereon. Furthermore, multiple systems may be applied in combination (for example, a combination of at least one of LTE and LTE-A with 5G). 【0103】 The processing procedures, sequences, flowcharts, etc., of each aspect / embodiment described in this disclosure may be reordered, provided they do not contradict each other. For example, the methods described in this disclosure present various step elements using exemplary order and are not limited to the specific order presented. 【0104】The specific operations described in this disclosure as being performed by a base station may, in some cases, be performed by its upper node. In a network consisting of one or more network nodes having a base station, it is clear that various operations performed for communication with a terminal can be performed by the base station and at least one other network node (for example, an MME or S-GW, but not limited to these). Although the above example illustrates the case where there is one other network node besides the base station, it may also be a combination of multiple other network nodes (for example, an MME and an S-GW). 【0105】 Information and signals (such as data) can be output from a higher layer (or lower layer) to a lower layer (or higher layer). Input and output may occur via multiple network nodes. 【0106】 Input and output information may be stored in a specific location (e.g., memory) or managed using a management table. Input and output information may be overwritten, updated, or appended to. Output information may be deleted. Input information may be transmitted to other devices. 【0107】 The determination may be made by a value represented by one bit (0 or 1), by a boolean value (true or false), or by a numerical comparison (for example, a comparison with a predetermined value). 【0108】 Each aspect / embodiment described in this disclosure may be used individually, in combination, or switched between as needed during implementation. Furthermore, notification of specific information (e.g., notification that "X is") is not limited to explicit notification, but may also be implicit (e.g., by not providing such notification). 【0109】Software should be broadly interpreted to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, procedures, functions, and so on, whether they are called software, firmware, middleware, microcode, hardware description languages, or by any other name. 【0110】 Furthermore, software, instructions, information, etc., may be transmitted and received via a transmission medium. For example, if software is transmitted from a website, server, or other remote source using at least one of wired technology (such as coaxial cable, fiber optic cable, twisted pair, or digital subscriber line (DSL)) and wireless technology (such as infrared or microwave), then at least one of these wired and wireless technologies is included in the definition of a transmission medium. 【0111】 The information, signals, etc. described in this disclosure may be represented using any of the various different technologies. For example, the data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof. 【0112】 In addition, terms used in this disclosure and terms necessary for understanding this disclosure may be replaced with terms having the same or similar meanings. For example, at least one of the channel and symbol may be a signal (signaling). Also, a signal may be a message. Furthermore, a component carrier (CC) may be called a carrier frequency, cell, frequency carrier, etc. 【0113】 The terms “system” and “network” as used in this disclosure are interchangeable. 【0114】Furthermore, the information, parameters, etc., described in this disclosure may be expressed using absolute values, relative values ​​from a given value, or other corresponding information. For example, wireless resources may be indicated by an index. 【0115】 The names used for the parameters described above are not restrictive in any way. Furthermore, the formulas and other expressions using these parameters may differ from those expressly disclosed in this disclosure. Various channels (e.g., PUCCH, PDCCH, etc.) and information elements can be identified by any suitable name, and therefore, the various names assigned to these various channels and information elements are not restrictive in any way. 【0116】 In this disclosure, terms such as "Base Station (BS)", "wireless base station", "fixed station", "NodeB", "eNodeB (eNB)", "gNodeB (gNB)", "access point", "transmission point", "reception point", "transmission / reception point", "cell", "sector", "cell group", "carrier", and "component carrier" may be used interchangeably. Base stations may also be referred to by terms such as macrocell, small cell, femtocell, and picocell. 【0117】 A base station can house one or more (e.g., three) cells (also called sectors). If a base station houses multiple cells, the entire coverage area of ​​the base station can be divided into multiple smaller areas, each of which may be provided with communication services by a base station subsystem (e.g., a Remote Radio Head, RRH). The terms "cell" or "sector" refer to part or all of the coverage area of ​​at least one of the base station and / or base station subsystems providing communication services in that coverage. 【0118】In this disclosure, the transmission of information by a base station to a terminal may be interpreted as the base station instructing the terminal to perform control or operation based on the information. 【0119】 In this disclosure, terms such as “terminal,” “user terminal,” “Mobile Station (MS),” and “User Equipment (UE)” may be used interchangeably. 【0120】 A mobile station may also be referred to by those skilled in the art as a subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriber station, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, client, or several other appropriate terms. 【0121】At least one of the base station and the mobile station may be called a transmitting device, a receiving device, a communication device, etc. At least one of the base station and the mobile station may also be a device mounted on a mobile body, the mobile body itself, etc. The mobile body refers to a movable object, and its speed of movement is arbitrary. This also includes the case when the mobile body is stationary. The mobile body includes, but is not limited to, vehicles, transport vehicles, automobiles, motorcycles, bicycles, connected cars, excavators, bulldozers, wheel loaders, dump trucks, forklifts, trains, buses, handcarts, rickshaws, ships and other watercraft, airplanes, rockets, satellites, drones (registered trademark), multicopters, quadcopters, balloons, and items mounted on them. The mobile body may also be a mobile body that moves autonomously based on operation commands. It may be a vehicle (e.g., a car, an airplane, etc.), an unmanned mobile body (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). Furthermore, at least one of the base station and the mobile station may include devices that do not necessarily move during communication operations. For example, at least one of the base station and the mobile station may be an Internet of Things (IoT) device such as a sensor. 【0122】 Furthermore, the term "base station" in this disclosure may be interpreted as "terminal." For example, the various aspects / embodiments of this disclosure may be applied to a configuration in which communication between a base station and a terminal is replaced with communication between multiple terminals (which may be called, for example, Device-to-Device (D2D), Vehicle-to-Everything (V2X), etc.). In this case, the terminal 200 may have the functions that the base station 100 has. Also, terms such as "uplink" and "downlink" may be interpreted as terms corresponding to terminal-to-terminal communication (for example, "side"). For example, uplink channel, downlink channel, etc., may be interpreted as side channel. 【0123】 Similarly, the term "terminal" in this disclosure may be replaced with "base station." In this case, the base station 100 may be configured to have the same functions as the terminal 200 described above. 【0124】 Figure 12 shows an example of the configuration of vehicle 2001. As shown in Figure 12, vehicle 2001 includes a drive unit 2002, a steering unit 2003, an accelerator pedal 2004, a brake pedal 2005, a shift lever 2006, left and right front wheels 2007, left and right rear wheels 2008, an axle 2009, an electronic control unit 2010, various sensors 2021 to 2029, an information service unit 2012, and a communication module 2013. 【0125】 The drive unit 2002 is composed of, for example, an engine, a motor, or a hybrid of an engine and a motor. 【0126】 The steering unit 2003 includes at least a steering wheel (also called a handle) and is configured to steer at least one of the front wheels and the rear wheels based on the operation of the steering wheel, which is operated by the user. 【0127】 The electronic control unit 2010 consists of a microprocessor 2031, memory (ROM, RAM) 2032, and communication ports (IO ports) 2033. Signals from various sensors 2021 to 2027 installed in the vehicle are input to the electronic control unit 2010. The electronic control unit 2010 may also be called an Electronic Control Unit (ECU). 【0128】 Signals from various sensors 2021 to 2029 include current signals from the current sensor 2021 that senses motor current, front and rear wheel rotation speed signals obtained by the rotation speed sensor 2022, front and rear wheel air pressure signals obtained by the air pressure sensor 2023, vehicle speed signals obtained by the vehicle speed sensor 2024, acceleration signals obtained by the acceleration sensor 2025, accelerator pedal depression signals obtained by the accelerator pedal sensor 2029, brake pedal depression signals obtained by the brake pedal sensor 2026, shift lever operation signals obtained by the shift lever sensor 2027, and detection signals obtained by the object detection sensor 2028 for detecting obstacles, vehicles, pedestrians, etc. 【0129】The Information Services Unit 2012 consists of various devices for providing (outputting) various types of information such as driving information, traffic information, and entertainment information, including car navigation systems, audio systems, speakers, televisions, and radios, and one or more ECUs that control these devices. The Information Services Unit 2012 uses information acquired from external devices via communication modules 2013, etc., to provide various multimedia information and multimedia services to the occupants of the vehicle 2001. 【0130】 The Information Services Unit 2012 may include input devices that accept input from external sources (e.g., keyboards, mice, microphones, switches, buttons, sensors, touch panels, etc.) and output devices that output to external sources (e.g., displays, speakers, LED lamps, touch panels, etc.). 【0131】 The driver assistance system unit 2030 consists of various devices that provide functions to prevent accidents or reduce the driver's workload, such as millimeter-wave radar, Light Detection and Ranging (LiDAR), cameras, positioning locators (e.g., GNSS), map information (e.g., high-definition (HD) maps, autonomous vehicle (AV) maps), gyro systems (e.g., Inertial Measurement Unit (IMU), Inertial Navigation System (INS)), Artificial Intelligence (AI) chips, and AI processors, as well as one or more ECUs that control these devices. The driver assistance system unit 2030 also sends and receives various information via the communication module 2013 to realize driver assistance functions or autonomous driving functions. 【0132】The communication module 2013 can communicate with the microprocessor 2031 and components of the vehicle 2001 via its communication port. For example, the communication module 2013 sends and receives data via the communication port 2033 between the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, left and right front wheels 2007, left and right rear wheels 2008, axle 2009, the microprocessor 2031 and memory (ROM, RAM) 2032 in the electronic control unit 2010, and sensors 2021 to 2029 provided in the vehicle 2001. 【0133】 The communication module 2013 is a communication device that can be controlled by the microprocessor 2031 of the electronic control unit 2010 and can communicate with external devices. For example, it can send and receive various types of information to and from external devices via wireless communication. The communication module 2013 may be located either inside or outside the electronic control unit 2010. The external device may be, for example, a base station or a mobile station. 【0134】 The communication module 2013 may transmit at least one of the following to an external device via wireless communication: signals from the various sensors 2021 to 2029 input to the electronic control unit 2010, information obtained based on said signals, and information based on input from an external source (user) obtained via the information service unit 2012. The electronic control unit 2010, the various sensors 2021 to 2029, the information service unit 2012, etc., may also be called input units that accept input. For example, the PUSCH transmitted by the communication module 2013 may include information based on the above input. 【0135】 The communication module 2013 receives various information (traffic information, signal information, vehicle-to-vehicle information, etc.) transmitted from external devices and displays it on the information service unit 2012 installed in the vehicle. The information service unit 2012 may also be called an output unit, which outputs information (for example, it outputs information to devices such as displays and speakers based on the PDSCH (or data / information decoded from the PDSCH) received by the communication module 2013). 【0136】Furthermore, the communication module 2013 stores various information received from external devices in memory 2032, which is available to the microprocessor 2031. Based on the information stored in memory 2032, the microprocessor 2031 may control the drive unit 2002, steering unit 2003, accelerator pedal 2004, brake pedal 2005, shift lever 2006, left and right front wheels 2007, left and right rear wheels 2008, axles 2009, sensors 2021 to 2029, etc., which are provided in the vehicle 2001. 【0137】 As used in this disclosure, the terms “determining” and “determining” may encompass a wide variety of actions. “Determining” may include, for example, judging, calculating, computing, processing, deriving, investigating, looking up, searching, or inquiring (e.g., searching in a table, database, or other data structure), or ascertaining. “Determining” may also include receiving (e.g., receiving information), transmitting (e.g., sending information), inputting, outputting, or accessing (e.g., accessing data in memory). Furthermore, “determining” may include resolving, selecting, choosing, establishing, or comparing. In other words, "judgment" and "decision" can include considering that some action has been "judged" or "decided." Also, "judgment (decision)" can be reinterpreted as "assuming," "expecting," or "considering." 【0138】The terms “connected,” “coupled,” and any variations thereof mean any direct or indirect connection or coupling between two or more elements, and may include the presence of one or more intermediate elements between two elements that are “connected” or “coupled” with each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, “connection” may be reinterpreted as “access.” As used in this disclosure, two elements may be considered to be “connected” or “coupled” with each other using at least one of one or more wires, cables, and printed electrical connections, and, in some non-limiting and non-exclusive examples, electromagnetic energy having wavelengths in the radio frequency domain, microwave domain, and optical (both visible and invisible) domain. 【0139】 The reference signal may also be abbreviated as RS, and may be called Pilot depending on the applicable standard. 【0140】 In this disclosure, the phrase "based on" does not mean "based solely on" unless otherwise specified. In other words, the phrase "based on" means both "based solely on" and "based at least on." 【0141】 Any reference to elements using the designations “first,” “second,” etc., as used in this disclosure does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient way to distinguish between two or more elements. Accordingly, references to the first and second elements do not imply that only two elements may be employed, or that the first element must precede the second element in any way. 【0142】 In the configuration of each of the above devices, "means" may be replaced with "part," "circuit," "device," etc. 【0143】Where the terms “include,” “including,” and variations thereof are used in this disclosure, these terms are intended to be inclusive, as is the term “comprising.” Furthermore, the term “or” as used in this disclosure is not intended to mean exclusive OR. 【0144】 A wireless frame may consist of one or more frames in the time domain. Each of these frames in the time domain may be called a subframe. A subframe may further consist of one or more slots in the time domain. A subframe may have a fixed time length (e.g., 1 ms) that is independent of numerology. 【0145】 Numerology may be communication parameters applied to at least one of the transmission and reception of a signal or channel. Numerology may include, for example, at least one of the following: subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, radio frame configuration, specific filtering processes performed by the transceiver in the frequency domain, and specific windowing processes performed by the transceiver in the time domain. 【0146】 A slot may consist of one or more symbols in the time domain (such as Orthogonal Frequency Division Multiplexing (OFDM) symbols or Single Carrier Frequency Division Multiple Access (SC-FDMA) symbols). A slot may also be a time unit based on neurology. 【0147】A slot may include multiple mini-slots. Each mini-slot may consist of one or more symbols in the time domain. Mini-slots may also be called sub-slots. Mini-slots may consist of fewer symbols than a slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a mini-slot may be called a PDSCH (or PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a mini-slot may be called a PDSCH (or PUSCH) mapping type B. 【0148】 Wireless frames, subframes, slots, minislots, and symbols all represent units of time when transmitting a signal. Different names may be used for each of these terms. 【0149】 For example, one subframe may be called a transmission time interval (TTI), multiple consecutive subframes may be called a TTI, or one slot or one minislot may be called a TTI. In other words, at least one of a subframe and a TTI may be a subframe (1 ms) in existing LTE, a period shorter than 1 ms (e.g., 1 to 13 symbols), or a period longer than 1 ms. Note that the unit representing the TTI may be called a slot, minislot, etc., instead of a subframe. 【0150】 Here, TTI refers to, for example, the smallest unit of time for scheduling in wireless communication. For example, in an LTE system, the base station schedules each terminal to allocate radio resources (such as the frequency bandwidth and transmission power available to each terminal) in TTI units. However, the definition of TTI is not limited to this. 【0151】TTI may be a transmission time unit for channel-encoded data packets (transport blocks), code blocks, code words, etc., or it may be a processing unit for scheduling, link adaptation, etc. Note that when a TTI is given, the actual time interval (e.g., number of symbols) in which the transport block, code block, code word, etc. are mapped may be shorter than the given TTI. 【0152】 Furthermore, if one slot or one mini-slot is referred to as TTI, then one or more TTIs (i.e., one or more slots or one or more mini-slots) may constitute the minimum time unit of scheduling. In addition, the number of slots (number of mini-slots) that constitute the minimum time unit of scheduling may be controlled. 【0153】 A TTI with a time length of 1 ms may also be called a normal TTI (TTI in LTE Rel. 8-12), a long TTI, a normal subframe, a long subframe, or a slot. A TTI shorter than a normal TTI may also be called a shortened TTI, a short TTI, a partial or fractional TTI, a shortened subframe, a short subframe, a mini slot, a subslot, or a slot. 【0154】 Furthermore, long TTIs (e.g., normal TTIs, subframes, etc.) may be interpreted as TTIs with a time length exceeding 1 ms, and short TTIs (e.g., shortened TTIs, etc.) may be interpreted as TTIs with a TTI length less than that of a long TTI but 1 ms or more. 【0155】 A resource block (RB) is a resource allocation unit in the time domain and frequency domain, and in the frequency domain, it may contain one or more consecutive subcarriers. The number of subcarriers in an RB may be the same regardless of the neurology, for example, 12. The number of subcarriers in an RB may be determined based on the neurology. 【0156】Furthermore, the time domain of RB may contain one or more symbols and may be the length of one slot, one minislot, one subframe, or one TTI. One TTI, one subframe, etc., may each consist of one or more resource blocks. 【0157】 One or more RBs may also be called Physical RBs (PRBs), Sub-Carrier Groups (SCGs), Resource Element Groups (REGs), PRB pairs, RB pairs, etc. 【0158】 Furthermore, a resource block may consist of one or more resource elements (REs). For example, one RE may be a radio resource area of ​​one subcarrier and one symbol. A bandwidth part (BWP) (also called a partial bandwidth, etc.) may represent a subset of consecutive common resource blocks (RBs) for a given neurology in a given carrier. Here, the common RBs may be identified by an index of the RBs relative to the common reference point of the carrier. PRBs may be defined in a BWP and numbered within that BWP. 【0159】 A BWP may include BWPs for UL (UL BWP) and BWPs for DL ​​(DL BWP). One or more BWPs may be configured within a single carrier for a UE. 【0160】 At least one of the configured BWPs may be active, and the UE does not need to assume that it will send or receive a given signal / channel outside of the active BWP. In this disclosure, terms such as "cell" and "carrier" may be read as "BWP". 【0161】The structures described above, such as wireless frames, subframes, slots, minislots, and symbols, are merely illustrative. For example, the number of subframes included in a wireless frame, the number of slots per subframe or wireless frame, the number of minislots included in a slot, the number of symbols and RBs included in a slot or minislot, the number of subcarriers included in an RB, and the number of symbols, symbol length, and cyclic prefix (CP) length within a TTI can be varied in various ways. 【0162】 The term "maximum transmit power" as used in this disclosure may mean the maximum transmit power, the nominal UE maximum transmit power, or the rated UE maximum transmit power. 【0163】 In this disclosure, if articles are added through translation, such as a, an, and the in English, this disclosure may include the fact that the noun following these articles is plural. 【0164】 In this disclosure, the term "A and B are different" may mean "A and B are different from each other." The term may also mean "A and B are each different from C." Terms such as "separate" and "combine" may be interpreted similarly to "different." 【0165】 Although the present disclosure has been described in detail above, it will be clear to those skilled in the art that the present disclosure is not limited to the embodiments described herein. The present disclosure can be implemented in modified and altered forms without departing from the intent and scope of the present disclosure as defined by the claims. Therefore, the descriptions in the present disclosure are illustrative and not intended to be restrictive in any way. 【0166】 (Note) The disclosure described above may also be expressed as follows: 【0167】The first feature is that the base station may include a transmitting unit that transmits instructions for lower-layer control mobility to other base stations via a control device of the core network, and a receiving unit that receives information from the other base stations via the control device regarding the transmission status of a reference signal used to transition a terminal as the mobility. 【0168】 The second feature is that, in the first feature, the transmitting unit may be a base station that transmits the reference signal using semi-persistent scheduling. 【0169】 A third feature is that, in the first or second feature, the receiving unit receives a message from the control device regarding the mobility instruction, and the information regarding the transmission status is included in the message, which may be a base station. 【0170】 A fourth feature is that, in the first or second feature, the transmitting unit transmits an update message to the other base station via the control device requesting an update of the mobility configuration information, and the receiving unit transmits a permission message for the update message from the other base station via the control device, and the information regarding the transmission status is included in the permission message, which may be a base station. 【0171】 A fifth feature is that, in the first or second feature, the receiving unit may receive an update message from the other base station via the control device requesting an update of the mobility setting information, and the information regarding the transmission status may be included in the update message. 【0172】 The sixth feature is that, in any of the first to fifth features, the transmitting unit transmits a control element of the media access control layer to the terminal, and the control element of the media access control layer includes resource information of the reference signal, which may be a base station. 【0173】10 Wireless communication system 20 NG-RAN 30 CN 100 Base station 110 Wireless signal transmission / reception unit 120 Amplifier unit 130 Modulation / demodulation unit 140 Control signal / reference signal processing unit 150 Encoding / decoding unit 160 Data transmission / reception unit 170 Control unit 200 Terminal 210 Wireless signal transmission / reception unit 220 Control unit 300 AMF 400 NWDAF 1001 Processor 1002 Memory 1003 Storage 1004 Communication device 1005 Input device 1006 Output device 1007 Bus 2001 Vehicle 2002 Drive unit 2003 Steering unit 2004 Accelerator pedal 2005 Brake pedal 2006 Shift lever 2007 Left and right front wheels 2008 Left and right rear wheels 2009 Axle 2010 Electronic Control Unit 2012 Information Services Unit 2013 Communication Module 2021 Current Sensor 2022 Rotation Speed ​​Sensor 2023 Air Pressure Sensor 2024 Vehicle Speed ​​Sensor 2025 Acceleration Sensor 2026 Brake Pedal Sensor 2027 Shift Lever Sensor 2028 Object Detection Sensor 2029 Accelerator Pedal Sensor 2030 Driving Assistance System Unit 2031 Microprocessor 2032 Memory (ROM, RAM) 2033 Communication Port (IO Port)

Claims

1. A base station comprising: a transmitting unit that transmits instructions for lower-layer control mobility to other base stations via a control device of the core network; and a receiving unit that receives information from the other base station via the control device regarding the transmission status of a reference signal used to transition a terminal as the mobility.

2. The base station according to claim 1, wherein the transmitting unit transmits the reference signal using semi-persistent scheduling.

3. The base station according to claim 1, wherein the receiving unit receives a message from the control device regarding the instruction for the mobility, and information regarding the transmission status is included in the message.

4. The base station according to claim 1, wherein the transmitting unit transmits an update message to the other base station via the control device requesting an update of the mobility configuration information, the receiving unit receives a permission message for the update message from the other base station via the control device, and information regarding the transmission status is included in the permission message.

5. The base station according to claim 1, wherein the receiving unit receives an update message from the other base station via the control device requesting an update of the mobility setting information, and the information regarding the transmission status is included in the update message.

6. The base station according to claim 1, wherein the transmitting unit transmits control elements of the media access control layer to the terminal, and the control elements of the media access control layer include resource information of the reference signal.

Images