Wireless base station and communications control method

Abstract

This wireless base station transmits, to another wireless base station or a network device on a core network, a handover-related message targeting a plurality of terminals that simultaneously perform handover within a specific period. The wireless base station sets the handover-related message including a list of the plurality of terminals.

Description

Radio base station and communication control method

[0001] The present disclosure relates to a radio base station and a communication control method for controlling handover of a terminal.

[0002] The 3rd Generation Partnership Project (3GPP: registered trademark) is developing specifications for the 5th generation mobile communication system (5G, also known as New Radio (NR) or Next Generation (NG)), and is also developing specifications for the next generation, known as Beyond 5G, 5G Evolution, or 6G.

[0003] In promoting the development of next-generation specifications, functional expansion of non-terrestrial networks (NTNs) is also being considered (Non-Patent Document 1). For example, NTN configurations using low-earth orbit satellites (LEOs), medium-earth orbit satellites (MEOs), or high-altitude platform stations (HAPSs) other than geostationary orbit satellites (GEOs) are being considered.

[0004] In such non-GEO-based NTNs, the cells (coverage) may move as the satellites move in orbit.

[0005] 3GPP TR 38.821 V16.2.0, 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Solutions for NR to support non-terrestrial networks (NTN) (Release 16), 3GPP, March 2023

[0006] When cells move along with orbital movements, the following issues are likely to arise: Specifically, when the cell edge passes through an area where many terminals (User Equipment, UE) are densely packed, handover of many UEs is required at the same time, which may lead to congestion in related interfaces, specifically the Xn interface between radio base stations (gNBs), the F1 interface between gNB-Central Unit (CU) and gNB-Distributed Unit (DU), and the NG interface between gNB and Access and Mobility Management Function (AMF).

[0007] Therefore, the following disclosure has been made in consideration of this situation, and aims to provide a radio base station and a communication control method that can effectively suppress congestion of related interfaces even when a cell (coverage) moves in accordance with the orbital movement of a satellite.

[0008] One aspect of the present disclosure is a radio base station (gNB100) that includes a transmitting unit (RRC / Xn processing unit 120, F1 processing unit 130, NG processing unit 135) that transmits handover-related messages targeted at multiple terminals that will simultaneously perform handover within a specific period of time to other radio base stations or network devices on a core network, and a control unit (control unit 140) that sets the handover-related messages including a list of the multiple terminals.

[0009] FIG. 1 is a schematic diagram of the overall configuration of a wireless communication system 10. FIG. 2 is a functional block diagram of a gNB 100 (CU). FIG. 3 is a functional block diagram of a gNB 100 (DU). FIG. 4 is a diagram showing an example of a communication sequence of handover-related messages according to an operation example 1. FIG. 5 is a diagram showing an example of the configuration of a handover-related message (Simultaneous UE Context Setup Request) according to the operation example 1. FIG. 6 is a diagram showing an example of the configuration of a handover-related message (Simultaneous Access Success) according to the operation example 1. FIG. 7 is a diagram showing an example of a communication sequence of handover-related messages according to an operation example 2. FIG. 8 is a diagram showing a modified example of the communication sequence of handover-related messages according to the operation example 2. FIG. 9 is a diagram showing an example of the configuration of a handover-related message (Simultaneous Handover Request) according to the operation example 2. FIG. 10 is a diagram showing an example of a communication sequence of handover-related messages according to an operation example 3. FIG. 11 is a diagram showing an example of the configuration of a handover-related message (Simultaneous Handover Required) according to the operation example 3. Fig. 12 is a diagram illustrating a modified example of the configuration of a handover-related message (Simultaneous Handover Required) according to Operation Example 3. Fig. 13 is a diagram illustrating an example of the hardware configuration of the gNB 100 and the UE 200. Fig. 14 is a diagram illustrating an example of the configuration of a vehicle 2001.

[0010] Hereinafter, embodiments will be described with reference to the drawings. Note that the same or similar reference numerals are used to designate the same functions or configurations, and descriptions thereof will be omitted as appropriate.

[0011] (1) Overall Schematic Configuration of Wireless Communication System Fig. 1 is a diagram showing the overall schematic configuration of a wireless communication system 10 according to this embodiment. The wireless communication system 10 is a wireless communication system conforming to 5G New Radio (NR) and includes a Next Generation-Radio Access Network 20 (hereinafter, NG-RAN 20) and a terminal 200 (User Equipment 200, hereinafter, UE 200).

[0012] The wireless communication system 10 may be a wireless communication system conforming to a method called Beyond 5G, 5G Evolution, or 6G, or may include a wireless communication system conforming to a method called Long Term Evolution (LTE) or 4G. The wireless communication system 10 may support functions related to the Industrial Internet of Things (IIoT) and Ultra-Reliable and Low Latency Communications (URLLC).

[0013] The NG-RAN 20 includes a radio base station 100 (hereinafter, gNB 100). Note that the specific configuration of the radio communication system 10, including the number of gNBs (or eNBs, etc.) and UEs, is not limited to the example shown in FIG. 1 .

[0014] The gNB 100 may also employ a fronthaul (FH) interface defined by the Open Radio Access Network Alliance (O-RAN). The gNB 100 may include an O-RAN Distributed Unit (O-DU) and an O-RAN Radio Unit (O-RU). The gNB 100 can function as a type of NG-RAN node.

[0015] The NG-RAN 20 actually includes multiple NG-RAN nodes, specifically, gNBs (or ng-eNBs), and is connected to a 5G-compliant core network (5GC, not shown). In the 5GC, the concept of CUPS (Control and User Plane Separation) may be introduced, in which the functions of the user plane and the control plane are clearly separated.

[0016] On the 5GC, an Access and Mobility Management Function 35 (hereinafter, AMF 35) that is included in the 5G system architecture and provides a mobility management function for the UE 200 and a Session Management Function (SMF, not shown) that provides a session management function may be provided. The AMF 35 and the SMF may be referred to as network devices.

[0017] In addition, a UDM / UDR (Unified Data Management / User Data Repository) may be connected to the AMF and / or SMF. Note that NG-RAN20 and 5GC may simply be referred to as a "network."

[0018] The gNB 100 is a radio base station conforming to NR and performs radio communication conforming to NR with the UE 200. The gNB 100 may be configured with a CU (Central Unit) and a DU (Distributed Unit), and the DU may be separated from the CU and installed in a different geographical location. One or more DUs may be connected to the CU.

[0019] The gNBs 100 (gNB-CUs) may be connected to each other via an Xn interface, the gNB-CUs and gNB-DUs may be connected to each other via an F1 interface, and the gNBs 100 (gNB-CUs) and the AMF 35, etc. may be connected to each other via an NG interface.

[0020] The gNB100 and UE200 are capable of supporting Massive MIMO, which generates more directional beams by controlling radio signals transmitted from multiple antenna elements; Carrier Aggregation (CA), which aggregates and uses multiple component carriers (CCs); and Dual Connectivity (DC), which enables simultaneous communication between the UE and multiple NG-RAN nodes.

[0021] In this embodiment, multi-radio dual connectivity (MR-DC) may be implemented in which one of the multiple gNBs 100 constitutes a master node (MN) and the other gNBs 100 constitute secondary nodes (SNs), specifically NR-NR dual connectivity (NR-DC) in which the gNBs constitute an MN (MgNB) and an SN (SgNB). Alternatively, E-UTRA-NR dual connectivity (EN-DC) or NR-E-UTRA dual connectivity (NE-DC) may be implemented.

[0022] In this way, UE200 supports dual connectivity, connecting to multiple gNB100s.

[0023] Any gNB 100 may be included in a master cell group (MCG), and other gNBs 100 (other radio base stations) may be included in a secondary cell group (SCG). The other gNBs 100 may be interpreted as SNs included in the SCG. The MNs or SNs may form cells C1 and C2.

[0024] The gNB 100 may be referred to as a radio base station or a network device. Note that the other gNB 100 may be interpreted as a radio base station to which the UE 200 is handed over.

[0025] In this embodiment, the wireless communication system 10 may include a non-terrestrial network (NTN). In an NTN, services are provided to areas that cannot be covered by a terrestrial network (TN) due to cost or other reasons by utilizing an NTN such as an artificial satellite 70 (hereinafter, satellite 70). The NTN can provide more reliable services. For example, the NTN is expected to be applied to the Internet of Things (IoT), ships, buses, trains, and critical communications. Furthermore, the NTN has scalability through efficient multicast or broadcast.

[0026] The satellite 70 may have the function of a relay station device, and the relay method may be either a transparent type or a regenerative type.

[0027] Note that a network including the gNB 100 and the UE 200 without including a satellite 70 may be referred to as a TN in contrast to an NTN. The UE 200 may communicate with the NG-RAN 20 via the NTN, or may communicate with the NG-RAN 20 via the TN (i.e., without going through the satellite 70).

[0028] The satellite 70 may also have the functionality of a gNB (radio base station). The type of satellite 70 is not particularly limited, but in this embodiment, low earth orbit satellites (LEO), medium earth orbit satellites (MEO), or high-altitude platform stations (HAPS) may be assumed. In other words, geostationary orbit satellites (GEO) may not be included. However, the satellite 70 is not necessarily limited to these satellites and may be interpreted as including spaceborne / airborne.

[0029] In such a non-GEO based NTN, the cells C1 and C2 (coverage) may move along with the orbital movement of the satellite 70.

[0030] The gNB 100 may include an NTN gateway (not shown), which transmits downlink (DL) signals to the satellite 70. The NTN gateway receives uplink (UL) signals from the satellite 70.

[0031] The wireless communication unit 150 relays a downlink signal received from the NTN gateway to the UE 200. The satellite 70 relays an uplink signal received from the UE 200 to the NTN gateway. The satellite 70 may be interpreted as a TRP (Transmission-Reception Point), a repeater, or a relay.

[0032] The wireless communication system 10 may also support multiple frequency ranges (FR).

[0033] FR1: 410 MHz to 7.125 GHz FR2: FR2-1: 24.25 GHz to 52.6 GHz FR2-2: Over 52.6 GHz to 71 GHz FR1 may use a Sub-Carrier Spacing (SCS) of 15, 30, or 60 kHz and a bandwidth (BW) of 5 to 100 MHz. FR2 is a higher frequency than FR1 and may use an SCS of 60 or 120 kHz (including 240 kHz) and a bandwidth (BW) of 50 to 400 MHz.

[0034] Furthermore, the wireless communication system 10 may also support frequency bands higher than the FR2 frequency band. Specifically, the wireless communication system 10 may support frequency bands above 52.6 GHz up to 114.25 GHz.

[0035] (2) Functional Block Configuration of Wireless Communication System Next, the functional block configuration of the wireless communication system 10 will be described. Specifically, the functional block configuration of the CU and DU of the gNB100 will be described. FIG. 2 is a functional block configuration diagram of the gNB100 (CU). FIG. 3 is a functional block configuration diagram of the gNB100 (DU). Note that FIGS. 2 and 3 are examples of main functional blocks related to the description of the embodiments, and the gNB100 may have other functional blocks. Also, FIGS. 2 and 3 show functional block configurations of the gNB100 and UE200, and for the hardware configuration, please refer to FIG. 13.

[0036] (2.1) CU The gNB100 (CU) comprises a NW connection unit 110, an RRC / Xn processing unit 120, an F1 processing unit 130 and a control unit 140.

[0037] The NW connection unit 110 provides interfaces necessary for connection with other RAN nodes constituting the network and core network nodes, etc. In particular, in this embodiment, the NW connection unit 110 can provide a connection interface (Xn) with other gNBs 100 via the NG-RAN 20 and a connection interface (F1) with a DU.

[0038] The RRC / Xn processing unit 120 executes various processes (XnAP) related to the radio resource control layer (RRC) and the Xn interface. For example, the RRC / Xn processing unit 120 can transmit an RRC Reconfiguration to the UE 200. The RRC / Xn processing unit 120 can also receive an RRC Reconfiguration Complete from the UE 200, which is a response to the RRC Reconfiguration.

[0039] The RRC / Xn processing unit 120 can transmit and receive inter-node messages via the Xn interface. Specifically, the RRC / Xn processing unit 120 can process the following inter-node messages (examples) specified in 3GPP TS38.423:

[0040] Handover Request Handover Request Ack Such inter-node messages may be specifically referred to as handover-related messages.

[0041] The RRC / Xn processing unit 120 can transmit handover-related messages intended for multiple UEs 200 that simultaneously perform handover within a specific period of time to another gNB 100. In this embodiment, the RRC / Xn processing unit 120 may constitute a transmission unit that transmits handover-related messages to another gNB 100.

[0042] Messages (examples) with the following names (tentative names are acceptable) may be added as handover-related messages via the Xn interface.

[0043] Simultaneous Handover Request Simultaneous Handover Request Ack Simultaneous Handover Request and Simultaneous Handover Request Ack may be interpreted as messages that bundle together multiple Handover Requests and multiple Handover Request Acks, respectively.

[0044] The F1 processing unit 130 executes various processes (F1AP) related to the F1 interface used for connection between the CU and DU. Specifically, the F1 processing unit 130 can send and receive messages between the CU and DU via the F1 interface.

[0045] Specifically, the F1 processing unit 130 can process the following messages (examples) defined in 3GPP TS38.473:

[0046] - UE Context Setup Request / Response - UE Context Modification Request / Response - Access Success Such messages may be specifically referred to as handover-related messages.

[0047] The F1 processing unit 130 can transmit handover-related messages intended for multiple UEs 200 that simultaneously perform handover within a specific period of time to another radio base station, specifically, a gNB-DU. In this embodiment, the F1 processing unit 130 may constitute a transmitting unit that transmits handover-related messages to another gNB-DU.

[0048] Messages (examples) with the following names (tentative names are acceptable) may be added as handover-related messages via the F1 interface.

[0049] Simultaneous UE Context Setup Request Simultaneous UE Context Setup Response The NG processing unit 135 executes various processes (F1AP) related to the NG interface used for connections between the gNB 100 and the AMF 35. Specifically, the NG processing unit 135 can send and receive inter-node messages between the gNB 100 and the AMF 35 via the NG interface.

[0050] Specifically, the NG processing unit 135 can process the following messages (examples) defined in 3GPP TS38.413:

[0051] Handover Required / Command Handover Request / Request Ack The NG processing unit 135 can transmit handover-related messages targeted at multiple UEs 200 that will simultaneously perform handover within a specific period of time to a network device on the core network, specifically, the AMF 35. In this embodiment, the NG processing unit 135 may constitute a transmitting unit that transmits handover-related messages to a network device on the core network.

[0052] Messages (examples) with the following names (tentative names are acceptable) may be added as handover-related messages via the NG interface.

[0053] Simultaneous Handover Required / Command Simultaneous Handover Request / Request Ack The control unit 140 controls each functional block constituting the gNB 100 (CU). In particular, in this embodiment, the control unit 140 can execute processing based on an F1AP message specified in 3GPP TS38.473, processing based on an XnAP message specified in 3GPP TS38.423, and processing based on an NGAP message specified in 3GPP TS38.413.

[0054] In this embodiment, the control unit 140 can configure a handover-related message including a list of multiple UEs 200. The handover-related message may refer to a message via the F1, Xn, or NG interface described above.

[0055] In particular, the handover-related message here may be interpreted as a message related to multiple UEs 200 simultaneously performing handover within a specific period of time as cells C1 and C2 (coverage) move along with the orbital movement of satellite 70. The specific period is not particularly limited, but may be interpreted as a certain period of time (e.g., from milliseconds to approximately one second or less) during which multiple handover-related messages must be processed in parallel.

[0056] The above-described example of the next handover-related message (tentative name) may be interpreted as a configuration in which multiple existing handover-related messages are combined together. That is, the control unit 140 can set a handover-related message instead of an existing unique handover message that is unique to each of the multiple UEs 200.

[0057] ・F1 Interface ・Simultaneous UE Context Setup Request ・Simultaneous UE Context Setup Response ・Xn Interface ・Simultaneous Handover Request ・Simultaneous Handover Request Ack ・NG Interface ・Simultaneous Handover Required / Command ・Simultaneous Handover Request / Request Ack The control unit 140 may set the handover-related message in which information common to multiple UEs 200 is expressed in a single information element (IE) and information specific to each of the multiple UEs 200 is listed. The information common to multiple UEs 200 and the information specific to each of the multiple UEs 200 may be referred to as a Common Part and a UE dedicated Part, respectively, in the handover-related message. An example of the configuration of the handover-related message will be described later.

[0058] The control unit 140 may set the handover-related message based on the maximum number of UEs 200 that can be included in one handover-related message. For example, the control unit 140 may determine the number of target UEs to be included in the handover-related message in accordance with an information element (tentative name: maxnoofSimultaneousHO) that specifies the maximum number of UEs that can be included in one handover-related message. maxnoofSimultaneousHO may be notified to the gNB 100 by, for example, signaling of an upper layer (RRC).

[0059] In this embodiment, the channels may include a control channel and a data channel, such as a physical downlink control channel (PDCCH), a physical uplink control channel (PUCCH), a physical random access channel (PRACH), and a physical broadcast channel (PBCH).

[0060] The data channels include a physical downlink shared channel (PDSCH) and a physical uplink shared channel (PUSCH).

[0061] The reference signal includes a Demodulation Reference Signal (DMRS), a Sounding Reference Signal (SRS), a Phase Tracking Reference Signal (PTRS), and a Channel State Information-Reference Signal (CSI-RS), and the signal includes a channel and a reference signal. Furthermore, the data may refer to data transmitted via a data channel.

[0062] (2.2) DU The gNB100 (DU) comprises a wireless communication unit 150, a NW connection unit 160, an F1 processing unit 170 and a control unit 180.

[0063] The wireless communication unit 150 transmits and receives wireless signals conforming to NR. Specifically, the wireless communication unit 150 receives an uplink signal (UL signal) conforming to NR from the UE 200 and transmits a downlink signal (DL signal) conforming to NR to the UE 200.

[0064] The NW connection unit 160 can provide a connection interface (F1) with other RAN nodes that make up the network, in this embodiment, the gNB100 (CU).

[0065] The F1 processing unit 170, like the F1 processing unit 130 of the CU, executes various processes (F1AP) related to the F1 interface used for connecting CUs and DUs. Specifically, the F1 processing unit 130 can send and receive messages between CUs and DUs via the F1 interface.

[0066] As described above, the F1 processing unit 170 can process messages specified in 3GPP TS38.473. In particular, in this embodiment, the F1 processing unit 170 may receive a Simultaneous UE Context Setup Request from the gNB-CU as a handover-related message, and may transmit a Simultaneous UE Context Setup Response to the gNB-CU.

[0067] The control unit 180 controls each functional block constituting the gNB 100 (DU). In particular, in this embodiment, the control unit 180 may execute control related to transmission and reception of handover-related messages.

[0068] Specifically, the control unit 180 may execute control related to handover based on information for multiple UEs included in a Simultaneous UE Context Setup Request received from the gNB-CU. Furthermore, the control unit 180 may generate the contents of a Simultaneous UE Context Setup Response according to the contents of the Simultaneous UE Context Setup Request, and transmit the generated Simultaneous UE Context Setup Response to the gNB-CU via the F1 processing unit 170.

[0069] (3) Operation of the Wireless Communication System Next, we will explain the operation of the wireless communication system 10. Specifically, we will explain the operation related to the processing of handover-related messages via the F1, Xn, or NG interface when a large number of UEs are handed over simultaneously, for example, when the cell (coverage) moves as the satellite 70 moves in its orbit.

[0070] (3.1) Issues As described above, in this embodiment, an NTN is used, and in a non-GEO-based NTN, the cells C1 and C2 (coverage) may move due to the orbital movement of the satellite 70.

[0071] In such a mobile NTN, when a cell edge crosses a densely populated area, handovers (HO) may occur for many UEs, potentially causing congestion on the F1, Xn, or NG interface. This congestion may occur whether the satellite 70 (relay station device) is a transparent or regenerative type.

[0072] Furthermore, these issues are not limited to the use of NTNs, where cells move on the ground, but also occur when a large number of UEs are moving at high speed during handover, or in small cell environments using FR2, etc., which may also lead to congestion on the F1, Xn, or NG interfaces.

[0073] (3.2) Overview of Operation In order to suppress or avoid the occurrence of the above-mentioned congestion, among the information contained in a message on the F1, Xn or NG interface that initiates a conventional handover for multiple UEs that are to perform handover simultaneously, UE-dedicated information may be configured as a list, and information common to multiple UEs that are the target of handover may be included in a single information element (IE) and transmitted in a single message.

[0074] For example, the following messages may be grouped together for multiple UEs to be handed over:

[0075] ・F1 message ・UE Context Setup Request / Response ・UE Context Modification Request / Response ・Access Success ・Xn message ・Handover Request / Request Ack ・NG message ・Handover Required / Command ・Handover Request / Request Ack

[0076] (3.3) Operation Example 1 In this operation example, an example of the configuration of a handover-related message via the F1 interface and an example of a communication sequence will be described.

[0077] FIG. 4 shows an example of a communication sequence of handover-related messages according to the first operation example.

[0078] FIG. 5 shows an example of the configuration of a handover-related message (Simultaneous UE Context Setup Request) according to the first operation example.

[0079] FIG. 6 shows an example of the structure of a handover-related message (Simultaneous Access Success) according to the first operation example.

[0080] As shown in Figure 4, the gNB-CU may send a Simultaneous UE Context Setup Request to the target gNB-DU for handover. The Simultaneous UE Context Setup Request may include handover requests for multiple UEs (e.g., UE1, UE2).

[0081] In response to receiving the Simultaneous UE Context Setup Request, the gNB-DU may return a Simultaneous UE Context Setup Response to the gNB-CU.

[0082] As shown in Figures 5 and 6, a message requesting handover may be added, including a list of UEs to be handed over simultaneously (UE to be Handovered List). The UE to be Handovered List may include information on multiple UEs to be subject to simultaneous handover.

[0083] As described above, the handover-related message may include a common part configured with information common to a plurality of UEs 200 and a UE dedicated part configured with information specific to each of the plurality of UEs 200 .

[0084] Furthermore, as mentioned above, the maximum number of UEs that can be included in the handover-related message may be indicated by maxnoofSimultaneousHO.

[0085] (3.4) Operation Example 2 In this operation example, an example of the configuration of a handover-related message via the Xn interface and an example of a communication sequence will be described.

[0086] FIG. 7 shows an example of a communication sequence of handover-related messages according to the second operation example.

[0087] FIG. 8 shows a modified example of the communication sequence of handover-related messages according to the second operation example.

[0088] FIG. 9 shows an example of the structure of a handover-related message (Simultaneous Handover Request) according to the second operation example.

[0089] As shown in Figure 7, the source gNB of the handover source may send a Simultaneous Handover Request to the target gNB of the handover destination. The Simultaneous Handover Request may include handover requests for multiple UEs (e.g., UE1, UE2).

[0090] In response to receiving the Simultaneous Handover Request, the target gNB may return a Simultaneous Handover Request Ack to the source gNB.

[0091] In the communication sequence example of Fig. 7, the Acks to UE1 and UE2 requested by the Simultaneous Handover Request and the Ack to UE3 requested by the existing (Legacy) message (Handover Request) are separated, but as shown in Fig. 8, the Acks targeted at the three UEs may be reported together by a Simultaneous Handover Request Ack at the discretion of the target gNB. Note that such an operation may be performed not only on the Xn interface but also on the F1 and NG interfaces in the same manner.

[0092] As shown in Fig. 9, a message requesting handover may be added, including a list of UEs to be handed over simultaneously (UE to be Handovered List). The UE to be Handovered List may include information on multiple UEs to be subject to simultaneous handover.

[0093] As described above, the handover-related message may include a common part configured with information common to a plurality of UEs 200 and a UE dedicated part configured with information specific to each of the plurality of UEs 200 .

[0094] Furthermore, as mentioned above, the maximum number of UEs that can be included in the handover-related message may be indicated by maxnoofSimultaneousHO.

[0095] (3.5) Operation Example 3 In this operation example, an example of the configuration of a handover-related message via the NG interface and an example of a communication sequence will be described.

[0096] FIG. 10 shows an example of a communication sequence of handover-related messages according to the third operation example.

[0097] FIG. 11 shows an example of the structure of a handover-related message (Simultaneous Handover Required) according to the third operation example.

[0098] FIG. 12 shows a modified example of the configuration of a handover-related message (Simultaneous Handover Required) according to the third operation example.

[0099] As shown in Figure 10, the source gNB of the handover source may send a Simultaneous Handover Required to the AMF. The Simultaneous Handover Required may include handover requests for multiple UEs (e.g., UE1, UE2).

[0100] In response to receiving the Simultaneous Handover Required, the AMF may send a Simultaneous Handover Request to the target gNB. In response to receiving the Simultaneous Handover Request, the target gNB may return a Simultaneous Handover Request Ack to the AMF. In response to receiving the Simultaneous Handover Request Ack, the AMF may send a Simultaneous Handover Command to the source gNB.

[0101] As shown in Fig. 11, a message requesting handover may be added, including a list of UEs to be handed over simultaneously (UE to be Handovered List). The UE to be Handovered List may include information on multiple UEs to be subject to simultaneous handover.

[0102] As described above, the handover-related message may include a common part configured with information common to a plurality of UEs 200 and a UE dedicated part configured with information specific to each of the plurality of UEs 200 .

[0103] Furthermore, as mentioned above, the maximum number of UEs that can be included in the handover-related message may be indicated by maxnoofSimultaneousHO.

[0104] In addition, in the example shown in Figure 11, information on Direct Forwarding Path Availability (whether or not a path is available for direct forwarding) is included in the Common Part, but as shown in Figure 12, depending on the status of the path, information on Direct Forwarding Path Availability may be treated as a UE dedicated Part and included in the UE dedicated Part.

[0105] It should be noted that such an operation may be performed not only on the NG interface, but also on the F1 and Xn interfaces in the same manner.

[0106] (4) Actions and Effects According to the above-described embodiment, the following actions and effects can be obtained. Specifically, even when multiple UEs simultaneously perform handover at the same time, handover-related messages that summarize information about the multiple UEs as a list can be transmitted and received. This significantly reduces the number of messages required compared to when handover-related messages are transmitted individually to each UE. This makes it possible to suppress or avoid congestion on the F1, Xn, and NG interfaces.

[0107] Furthermore, the handover-related message can include a Common Part consisting of information common to multiple UEs 200 and a UE dedicated Part consisting of information specific to each of the multiple UEs 200, so that the information required for handover can be transmitted while effectively reducing the number of required messages.

[0108] In addition, the maximum number of UEs that can be included in the handover-related message is defined by maxnoofSimultaneousHO, so that a handover-related message of an appropriate size can be constructed according to the cell configuration, etc., enabling flexible operation with reduced signaling overhead.

[0109] (5) Other Embodiments Although the embodiments have been described above, it will be obvious to those skilled in the art that the present invention is not limited to the description of the embodiments, and that various modifications and improvements are possible.

[0110] For example, in the above-described embodiment, an example of the configuration of a handover-related message in the F1, Xn or NG interface was described, but the information contained in the Common Part consisting of information common to multiple UEs 200, or the UE dedicated Part consisting of information specific to each of multiple UEs 200, may be other than the example configuration, and may be dynamically changed by upper layer signaling, etc.

[0111] Also, in the above description, configure, activate, update, indicate, enable, specify, and select may be interchangeable. Similarly, link, associate, correspond, and map may be interchangeable, and allocate, assign, monitor, and map may be interchangeable.

[0112] Furthermore, specific, dedicated, UE-specific, and UE-dedicated may be interchangeable. Similarly, common, shared, group-common, UE-common, and UE-shared may be interchangeable.

[0113] In the present disclosure, terms such as "precoding," "precoder," "weight (precoding weight)," "Quasi-Co-Location (QCL)," "Transmission Configuration Indication state (TCI state)," "spatial relation," "spatial domain filter," "transmit power," "phase rotation," "antenna port," "antenna port group," "layer," "number of layers," "rank," "resource," "resource set," "resource group," "beam," "beam width," "beam angle," "antenna," "antenna element," "panel," etc. may be used interchangeably.

[0114] Furthermore, the block diagrams (FIGS. 2 and 3) used in the description of the above-described embodiments show functional blocks. These functional blocks (components) are realized by any combination of hardware and / or software. Furthermore, the method for realizing each functional block is not particularly limited. That is, each functional block may be realized using a single device that is physically or logically coupled, or may be realized using two or more physically or logically separated devices that are directly or indirectly connected (e.g., wired, wireless, etc.) and these multiple devices. The functional block may also be realized by combining software with the single device or multiple devices.

[0115] Functions include, but are not limited to, judgment, determination, judgment, calculation, computation, processing, derivation, investigation, search, confirmation, reception, transmission, output, access, resolution, selection, selection, establishment, comparison, assumption, expectation, consideration, broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, and assignment. For example, a functional block (component) that performs transmission is called a transmitting unit or transmitter. As mentioned above, there are no particular limitations on how each is implemented.

[0116] Furthermore, the above-described gNB100 (CU, DU) and UE200 may function as a computer that performs processing of the wireless communication method of the present disclosure. Figure 13 is a diagram showing an example of the hardware configuration of the gNB100 and UE200. As shown in Figure 13, the gNB100 and UE200 may be configured as a computer device including a processor 1001, a memory 1002, a storage 1003, a communication device 1004, an input device 1005, an output device 1006, a bus 1007, etc.

[0117] In the following description, the term "apparatus" can be interpreted as a circuit, a device, a unit, etc. The hardware configuration of the apparatus may be configured to include one or more of the apparatuses shown in the drawings, or may be configured to exclude some of the apparatuses.

[0118] Each functional block of gNB100 (see Figures 2 and 3) is realized by any hardware element of the computer device or a combination of such hardware elements.

[0119] In addition, each function in gNB100 is realized by loading specified software (programs) onto hardware such as processor 1001 and memory 1002, causing processor 1001 to perform calculations, control communication by communication device 1004, and control at least one of reading and writing data in memory 1002 and storage 1003.

[0120] The processor 1001 controls the entire computer by running, for example, an operating system, and may be configured as a central processing unit (CPU) including an interface with peripheral devices, a control unit, an arithmetic unit, and registers.

[0121] The processor 1001 also reads programs (program codes), 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 in accordance with these. The programs used are those that cause a computer to execute at least some of the operations described in the above-described embodiments. Furthermore, the various processes described above may be executed by a single processor 1001, or may be executed simultaneously or sequentially by two or more processors 1001. The processor 1001 may be implemented by one or more chips. The programs may be transmitted from a network via a telecommunications line.

[0122] The memory 1002 is a computer-readable recording medium and may be configured by at least one of, for example, a read-only memory (ROM), an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a random access memory (RAM), etc. The memory 1002 may also be called a register, a cache, a main memory (primary storage device), etc. The memory 1002 may store a program (program code), a software module, etc., capable of executing a method according to an embodiment of the present disclosure.

[0123] Storage 1003 is a computer-readable recording medium, and may be, for example, at least one of an optical disk such as a Compact Disc ROM (CD-ROM), a hard disk drive, a flexible disk, a magneto-optical disk (e.g., a compact disk, a digital versatile disk, a Blu-ray disc), a smart card, a flash memory (e.g., a card, a stick, a key drive), a floppy disk, a magnetic strip, etc. Storage 1003 may also be referred to as an auxiliary storage device. The above-mentioned recording medium may be, for example, a database, a server, or other suitable medium including at least one of memory 1002 and storage 1003.

[0124] The communication device 1004 is hardware (transmission / reception device) for communicating between computers via at least one of a wired network and a wireless network, and is also called, for example, a network device, a network controller, a network card, or a communication module.

[0125] The communication device 1004 may be configured to include a high-frequency switch, a duplexer, a filter, a frequency synthesizer, etc. to realize, for example, at least one of Frequency Division Duplex (FDD) and Time Division Duplex (TDD).

[0126] The input device 1005 is an input device (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that receives input from the outside. The output device 1006 is an output device (e.g., a display, a speaker, an LED lamp, etc.) that outputs to the outside. Note that the input device 1005 and the output device 1006 may be integrated into one device (e.g., a touch panel).

[0127] Furthermore, each device such as the processor 1001 and the memory 1002 is connected to a bus 1007 for communicating information. The bus 1007 may be configured using a single bus, or may be configured using different buses between each device.

[0128] Furthermore, the device 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), or a field programmable gate array (FPGA), and some or all of the functional blocks may be realized by the hardware. For example, the processor 1001 may be implemented using at least one of these pieces of hardware.

[0129] Furthermore, the notification of information is not limited to the aspects / embodiments described in the present disclosure, and may be performed using other methods. For example, the notification of information may be performed by physical layer signaling (e.g., Downlink Control Information (DCI), Uplink Control Information (UCI)), higher layer signaling (e.g., RRC signaling, Medium Access Control (MAC) signaling, broadcast information (Master Information Block (MIB), System Information Block (SIB))), other signals, or a combination thereof. Furthermore, the RRC signaling may be referred to as an RRC message, and may be, for example, an RRC Connection Setup message, an RRC Connection Reconfiguration message, or the like.

[0130] Each aspect / embodiment described in the present disclosure may be applied to at least one of a system using Long Term Evolution (LTE), LTE-Advanced (LTE-A), SUPER 3G, IMT-Advanced, a 4th generation mobile communication system (4G), a 5th generation mobile communication system (5G), a 6th generation mobile communication system (6G), an xth generation mobile communication system (xG) (where x is, for example, an integer or a decimal), Future Radio Access (FRA), New Radio (NR), W-CDMA (registered trademark), GSM (registered trademark), CDMA2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registered trademark)), IEEE 802.20, Ultra-WideBand (UWB), Bluetooth (registered trademark), or other suitable system, and a next-generation system extended based on these. Furthermore, a combination of multiple systems (e.g., a combination of at least one of LTE and LTE-A with 5G) may also be applied.

[0131] The order of the procedures, sequences, flowcharts, etc. of each aspect / embodiment described in this disclosure may be changed unless it is consistent. For example, the methods described in this disclosure present elements of various steps using an example order, and are not limited to the particular order presented.

[0132] In the present disclosure, a specific operation described as being performed by a base station may also be performed by its upper node in some cases. 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 may be performed by at least one of the base station and another network node other than the base station (e.g., MME or S-GW, etc., but are not limited to these). Although the above example illustrates a case where there is one other network node other than the base station, a combination of multiple other network nodes (e.g., MME and S-GW) may also be used.

[0133] Information, signals (information, etc.) may be output from a higher layer (or a lower layer) to a lower layer (or a higher layer), or may be input and output via multiple network nodes.

[0134] The input and output information may be stored in a specific location (for example, a memory) or may be managed using a management table. The input and output information may be overwritten, updated, or added to. The output information may be deleted. The input information may be transmitted to another device.

[0135] The determination may be made based on a value represented by one bit (0 or 1), a Boolean value (true or false), or a numerical comparison (e.g., comparison with a predetermined value).

[0136] The aspects / embodiments described in this disclosure may be used alone, in combination, or switched depending on the implementation. Notification of predetermined information (e.g., notification that "X is true") is not limited to explicit notification, but may be implicit (e.g., not notifying the predetermined information).

[0137] Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

[0138] Software, instructions, information, etc. may also be transmitted or received over a transmission medium. For example, if software is transmitted from a website, server, or other remote source using wired technologies (such as coaxial cable, fiber optic cable, twisted pair, Digital Subscriber Line (DSL)), and / or wireless technologies (such as infrared, microwave), then these wired and / or wireless technologies are included within the definition of transmission media.

[0139] The information, signals, etc. described in this disclosure may be represented using any of a variety of different technologies. For example, data, instructions, commands, information, signals, bits, symbols, chips, etc. that may be referred to throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or magnetic particles, optical fields or photons, or any combination thereof.

[0140] Note that terms described 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 a channel and a symbol may be a signal (signaling). Furthermore, a signal may be a message. Furthermore, a component carrier (CC) may be called a carrier frequency, a cell, a frequency carrier, etc.

[0141] As used in this disclosure, the terms "system" and "network" are used interchangeably.

[0142] Furthermore, the information, parameters, etc. described in the present disclosure may be expressed using absolute values, may be expressed using relative values ​​from a predetermined value, or may be expressed using other corresponding information. For example, a radio resource may be indicated by an index.

[0143] The names used for the above-described parameters are not intended to be limiting in any way. Furthermore, the mathematical expressions using these parameters may differ from those explicitly disclosed in this disclosure. The various channels (e.g., PUCCH, PDCCH, etc.) and information elements may be identified by any suitable names, and therefore the various names assigned to these various channels and information elements are not intended to be limiting in any way.

[0144] In this disclosure, terms such as "base station (BS)," "radio 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.

[0145] A base station can accommodate one or more (e.g., three) cells (also called sectors). When a base station accommodates multiple cells, the overall coverage area of ​​the base station can be divided into multiple smaller areas, and each smaller area can be provided with communication services by a base station subsystem (e.g., a small indoor base station (Remote Radio Head: RRH)).

[0146] The terms "cell" or "sector" refer to part or all of the coverage area of ​​a base station and / or base station subsystem that provides communication services within that coverage area.

[0147] In the present disclosure, the base station transmitting information to a terminal may be interpreted as the base station instructing the terminal to control or operate based on the information.

[0148] In this disclosure, the terms "Mobile Station (MS)," "user terminal," "User Equipment (UE)," "terminal," etc. may be used interchangeably.

[0149] 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 some other suitable terminology.

[0150] At least one of the base station and the mobile station may be referred to as a transmitting device, a receiving device, a communication device, etc. At least one of the base station and the mobile station may be a device mounted on a mobile object, the mobile object itself, etc. The mobile object may be a vehicle (e.g., a car, an airplane, etc.), an unmanned mobile object (e.g., a drone, an autonomous vehicle, etc.), or a robot (manned or unmanned). At least one of the base station and the mobile station may also 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.

[0151] Furthermore, a base station in the present disclosure may be read as a mobile station (user terminal, the same applies hereinafter). For example, the aspects / embodiments of the present disclosure may be applied to a configuration in which communication between a base station and a mobile station is replaced with communication between multiple mobile stations (which may be called, for example, Device-to-Device (D2D) or Vehicle-to-Everything (V2X)). In this case, the mobile station may be configured to have the functions of a base station. Furthermore, terms such as "uplink" and "downlink" may be read as terms corresponding to terminal-to-terminal communication (for example, "side"). For example, terms such as an uplink channel and a downlink channel may be read as a side channel (or sidelink).

[0152] Similarly, a mobile station in the present disclosure may be interpreted as a base station, in which case the base station may have the functions of a mobile station.

[0153] A radio frame may be composed of one or more frames in the time domain. Each of the one or more frames in the time domain may be called a subframe. A subframe may further be composed 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.

[0154] Numerology may be communication parameters that apply to the transmission and / or reception of a signal or channel, such as subcarrier spacing (SCS), bandwidth, symbol length, cyclic prefix length, transmission time interval (TTI), number of symbols per TTI, radio frame structure, specific filtering operations performed by the transceiver in the frequency domain, and specific windowing operations performed by the transceiver in the time domain.

[0155] A slot may consist of one or more symbols in the time domain (such as an Orthogonal Frequency Division Multiplexing (OFDM) symbol, a Single Carrier Frequency Division Multiple Access (SC-FDMA) symbol, etc.) A slot may be a numerology-based time unit.

[0156] A slot may include multiple minislots. Each minislot may consist of one or more symbols in the time domain. A minislot may also be called a subslot. A minislot may consist of fewer symbols than a slot. A PDSCH (or PUSCH) transmitted in a time unit larger than a minislot may be called PDSCH (or PUSCH) mapping type A. A PDSCH (or PUSCH) transmitted using a minislot may be called PDSCH (or PUSCH) mapping type B.

[0157] The radio frame, subframe, slot, minislot, and symbol all represent time units for transmitting signals, and may be referred to by other names corresponding to the radio frame, subframe, slot, minislot, and symbol.

[0158] For example, one subframe may be referred to as a transmission time interval (TTI), multiple consecutive subframes may be referred to as a TTI, or one slot or one minislot may be referred to as a TTI. That is, at least one of the subframe and the TTI may be a subframe (1 ms) in existing LTE, a period shorter than 1 ms (e.g., 1-13 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.

[0159] Here, TTI refers to, for example, the smallest time unit for scheduling in wireless communication. For example, in an LTE system, a base station schedules each user terminal to allocate radio resources (such as frequency bandwidth and transmission power that can be used by each user terminal) in TTI units. Note that the definition of TTI is not limited to this.

[0160] The TTI may be a transmission time unit for a channel-encoded data packet (transport block), a code block, a code word, etc., or may be a processing unit for scheduling, link adaptation, etc. When a TTI is given, the time interval (e.g., the number of symbols) to which a transport block, a code block, a code word, etc. is actually mapped may be shorter than the TTI.

[0161] In addition, when one slot or one minislot is called a TTI, one or more TTIs (i.e., one or more slots or one or more minislots) may be the minimum time unit for scheduling, and the number of slots (minislots) constituting the minimum time unit for scheduling may be controlled.

[0162] A TTI having a time length of 1 ms may be referred to as a regular TTI (TTI in LTE Rel. 8-12), normal TTI, long TTI, regular subframe, normal subframe, long subframe, slot, etc. A TTI shorter than a regular TTI may be referred to as a shortened TTI, short TTI, partial or fractional TTI, shortened subframe, short subframe, minislot, subslot, slot, etc.

[0163] In addition, a long TTI (e.g., a normal TTI, a subframe, etc.) may be interpreted as a TTI having a time length of more than 1 ms, and a short TTI (e.g., a shortened TTI, etc.) may be interpreted as a TTI having a TTI length shorter than the TTI length of a long TTI and equal to or greater than 1 ms.

[0164] A resource block (RB) is a resource allocation unit in the time domain and the frequency domain, and may include one or more consecutive subcarriers in the frequency domain. The number of subcarriers included in an RB may be the same regardless of numerology, for example, 12. The number of subcarriers included in an RB may be determined based on numerology.

[0165] The time domain of an RB may include one or more symbols and may have a length of one slot, one minislot, one subframe, or one TTI, each of which may consist of one or more resource blocks.

[0166] Note that one or more RBs may also be called a physical resource block (PRB), a sub-carrier group (SCG), a resource element group (REG), a PRB pair, an RB pair, etc.

[0167] Furthermore, a resource block may be composed of one or more resource elements (REs). For example, one RE may be a radio resource region of one subcarrier and one symbol.

[0168] A Bandwidth Part (BWP) (which may also be referred to as a fractional bandwidth) may represent a subset of contiguous common resource blocks (RBs) for a given numerology on a given carrier, where the common RBs may be identified by their index relative to a common reference point of the carrier. PRBs may be defined in a given BWP and numbered within that BWP.

[0169] The BWP may include a BWP for UL (UL BWP) and a BWP for DL ​​(DL BWP). One or more BWPs may be configured for a UE within one carrier.

[0170] At least one of the configured BWPs may be active, and the UE may not expect to transmit or receive a given signal / channel outside the active BWP. Note that the terms "cell," "carrier," etc. in this disclosure may be read as "BWP."

[0171] The above-described structures of the radio frame, subframe, slot, minislot, and symbol are merely examples. For example, the number of subframes included in a radio frame, the number of slots per subframe or radio 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, the number of symbols in a TTI, the symbol length, the cyclic prefix (CP) length, and other configurations may be changed in various ways.

[0172] The terms "connected," "coupled," or any variation thereof, refer to 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" to each other. The coupling or connection between elements may be physical, logical, or a combination thereof. For example, "connected" may be read as "access." As used in this disclosure, two elements may be considered to be "connected" or "coupled" to each other using one or more wires, cables, and / or printed electrical connections, as well as electromagnetic energy having wavelengths in the radio frequency range, microwave range, and optical (both visible and invisible) range, as some non-limiting and non-exhaustive examples.

[0173] The reference signal may also be abbreviated as Reference Signal (RS) and may be called a pilot depending on the applicable standard.

[0174] As used in this disclosure, the phrase "based on" does not mean "based only on," unless expressly stated otherwise. In other words, the phrase "based on" means both "based only on" and "based at least on."

[0175] The "means" in the configuration of each of the above devices may be replaced with "part," "circuit," "device," etc.

[0176] As used in this disclosure, any reference to an element using a designation such as "first," "second," etc. does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements. Thus, a reference to a first and a second element does not imply that only two elements may be employed therein or that the first element must precede the second element in some way.

[0177] When the terms "include," "including," and variations thereof are used in this disclosure, these terms are intended to be inclusive, similar to the term "comprising." Furthermore, when the term "or" is used in this disclosure, it is not intended to be an exclusive or.

[0178] In this disclosure, where articles are added by translation, such as a, an, and the in English, the disclosure may include that the nouns following these articles are in the plural form.

[0179] As used in this disclosure, the terms "determining" and "determining" may encompass a wide variety of actions. "Determining" and "determining" may include, for example, judging, calculating, computing, processing, deriving, investigating, looking up, searching, inquiring (e.g., searching in a table, database, or other data structure), ascertaining, and the like. "Determining" and "determining" may also include receiving (e.g., receiving information), transmitting (e.g., sending information), input, output, accessing (e.g., accessing data in memory), and the like. Furthermore, "judgment" and "decision" can include regarding resolving, selecting, choosing, establishing, comparing, etc. as having been "judged" or "decided." In other words, "judgment" and "decision" can include regarding some action as having been "judged" or "decided." Furthermore, "judgment (decision)" can be interpreted as "assuming," "expecting," "considering," etc.

[0180] In the present 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 "coupled" may also be interpreted in the same way as "different."

[0181] 14 shows an example of the configuration of a vehicle 2001. As shown in Fig. 14, the 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.

[0182] The drive unit 2002 is composed of, for example, an engine, a motor, or a hybrid of an engine and a motor. 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 operated by the user. The electronic control unit 2010 is composed of a microprocessor 2031, memory (ROM, RAM) 2032, and a communication port (IO port) 2033. Signals from various sensors 2021 to 2027 provided in the vehicle are input to the electronic control unit 2010. The electronic control unit 2010 may also be called an ECU (Electronic Control Unit).

[0183] The signals from the various sensors 2021 to 2028 include a current signal from a current sensor 2021 that senses the current of the motor, a rotation speed signal of the front and rear wheels obtained by a rotation speed sensor 2022, an air pressure signal of the front and rear wheels obtained by an air pressure sensor 2023, a vehicle speed signal obtained by a vehicle speed sensor 2024, an acceleration signal obtained by an acceleration sensor 2025, an accelerator pedal depression amount signal obtained by an accelerator pedal sensor 2029, a brake pedal depression amount signal obtained by a brake pedal sensor 2026, a shift lever operation signal obtained by a shift lever sensor 2027, and a detection signal for detecting obstacles, vehicles, pedestrians, etc. obtained by an object detection sensor 2028.

[0184] The information service unit 2012 is composed of various devices, such as a car navigation system, an audio system, speakers, a television, and a radio, for providing (outputting) various types of information, such as driving information, traffic information, and entertainment information, and one or more ECUs for controlling these devices. The information service unit 2012 uses information acquired from external devices via the communication module 2013, etc., to provide various types of multimedia information and multimedia services to the occupants of the vehicle 1.

[0185] The information service unit 2012 may include input devices (e.g., keyboards, mice, microphones, switches, buttons, sensors, touch panels, etc.) that accept input from the outside, and may also include output devices (e.g., displays, speakers, LED lamps, touch panels, etc.) that output to the outside.

[0186] The driving assistance system unit 2030 is composed of various devices that provide functions for preventing accidents and reducing the driver's driving burden, such as millimeter-wave radar, LiDAR (Light Detection and Ranging), cameras, positioning locators (e.g., GNSS, etc.), map information (e.g., high-definition (HD) maps, autonomous vehicle (AV) maps, etc.), gyro systems (e.g., IMU (Inertial Measurement Unit), INS (Inertial Navigation System), etc.), AI (Artificial Intelligence) chips, and AI processors, as well as one or more ECUs that control these devices. The driving assistance system unit 2030 also transmits and receives various information via the communication module 2013 to realize driving assistance functions or autonomous driving functions.

[0187] The communication module 2013 can communicate with the microprocessor 2031 and components of the vehicle 1 via the communication port. For example, the communication module 2013 transmits and receives data via the communication port 2033 to and from a driving 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, a microprocessor 2031 and memory (ROM, RAM) 2032 in the electronic control unit 2010, and sensors 2021 to 2028, which are provided in the vehicle 2001.

[0188] 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 an external device. For example, it transmits and receives various information to and from the external device 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, a mobile station, or the like.

[0189] The communication module 2013 may transmit at least one of signals from the above-mentioned various sensors 2021 to 2028 input to the electronic control unit 2010, information obtained based on the signals, and information based on input from the outside (user) obtained via the information service unit 2012 to an external device via wireless communication. The electronic control unit 2010, the various sensors 2021 to 2028, the information service unit 2012, etc. may be referred to as input units that accept input. For example, the PUSCH transmitted by the communication module 2013 may include information based on the above-mentioned input.

[0190] The communication module 2013 receives various information (traffic information, traffic signal information, vehicle-to-vehicle information, etc.) transmitted from external devices and displays it on an information service unit 2012 provided in the vehicle. The information service unit 2012 may also be called an output unit that outputs information (for example, outputs information to a device such as a display or speaker based on the PDSCH (or data / information decoded from the PDSCH) received by the communication module 2013). The communication module 2013 also stores the various information received from external devices in a memory 2032 that can be used by the microprocessor 2031. Based on the information stored in the 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 2028, and the like provided in the vehicle 2001.

[0191] Although the present disclosure has been described in detail above, it is 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 spirit and scope of the present disclosure as defined by the claims. Therefore, the description of the present disclosure is intended to be illustrative and does not have any limiting meaning on the present disclosure.

[0192] (Additional Note) The above disclosure may be expressed as follows: A first feature is a radio base station including: a transmitter that transmits a handover-related message targeted at a plurality of terminals that are to simultaneously execute handover within a specific period to another radio base station or a network device on a core network; and a controller that sets the handover-related message to include a list of the plurality of terminals.

[0193] A second feature is that, in the first feature, the control unit represents information common to the plurality of terminals with a single information element, and sets the handover-related message to list information specific to each of the plurality of terminals.

[0194] A third feature based on the first or second feature is that the control unit sets the handover-related message based on a maximum number of the terminals that can be included in one handover-related message.

[0195] A fourth feature is any one of the first to third features, wherein the control unit sets the handover-related message instead of an existing unique handover message that is unique to each of the plurality of terminals.

[0196] 10 Wireless communication system 20 NG-RAN 35 AMF 70 Satellite 100 gNB 110 NW connection unit 120 RRC / Xn processing unit 130 F1 processing unit 135 NG processing unit 140 Control unit 150 Wireless communication unit 160 NW connection unit 170 F1 processing unit 180 Control unit 200 UE 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 service unit 2013 Communication module 2021 Current sensor 2022 RPM 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 section 2031 Microprocessor 2032 Memory (ROM, RAM) 2033 Communication port

Claims

1. A radio base station comprising: a transmitting unit that transmits handover-related messages targeted at multiple terminals that will simultaneously perform handover within a specific period of time to other radio base stations or network devices on a core network; and a control unit that sets the handover-related messages to include a list of the multiple terminals.

2. The radio base station according to claim 1, wherein the control unit sets the handover-related message in which information common to the plurality of terminals is expressed in a single information element and information specific to each of the plurality of terminals is listed.

3. The radio base station according to claim 1, wherein the control unit sets the handover-related message based on a maximum number of the terminals that can be included in one handover-related message.

4. The radio base station according to claim 1, wherein the control unit sets the handover-related message in place of an existing unique handover message that is unique to each of the plurality of terminals.

5. A communication control method by a radio base station, comprising: a step of transmitting a handover-related message targeted at a plurality of terminals that will simultaneously perform handover within a specific period of time to another radio base station or a network device on a core network; and a step of setting the handover-related message to include a list of the plurality of terminals.

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