Control terminal, network node, communication method, chipset, program, and mobile communication system

Abstract

Provided is an NCR-UE (control terminal) that controls an NCR device (relay device) for relaying a radio signal between a gNB (base station) and a UE (user device) in a mobile communication system, the NCR-UE receiving, from the gNB, setting information that is used to cause the NCR device to direct a beam to the UE and using the setting information to control the NCR device to direct the beam toward the UE.

Description

Technical Field

[0001] The present disclosure relates to a control terminal, a base station, and a communication method used in a mobile communication system.

Background Art

[0002] In recent years, the fifth-generation (5G) mobile communication system has attracted attention. NR (New Radio), which is a radio access technology of the 5G system, enables broadband transmission in a high-frequency band compared to LTE (Long Term Evolution), which is a fourth-generation radio access technology.

[0003] Since radio signals (radio waves) in high-frequency bands such as the millimeter-wave band or the terahertz band have high directivity, reducing the coverage of the base station becomes an issue. To solve such an issue, a repeater device that relays radio signals between a base station and a user device and can be controlled from a network has attracted attention (see, for example, Non-Patent Document 1). Such a repeater device can expand the coverage of the base station while suppressing the occurrence of interference, for example, by amplifying a radio signal received from the base station and transmitting it by directional transmission.

Prior Art Documents

Non-Patent Documents

[0004]

Non-Patent Document 1

Summary of the Invention

[0005] The control terminal according to the first aspect is a device that controls a relay device that relays radio signals between a base station and a user device in a mobile communication system. The control terminal includes a receiving unit that receives, from the base station, setting information used for the relay device to direct a beam toward the user device, and a control unit that controls the relay device to direct the beam toward the user device based on the setting information.

[0006] The base station according to the second aspect is the base station used in a mobile communication system having a control terminal that controls a relay device that relays radio signals between the base station and a user device. The base station includes a transmitting unit that transmits, to the control terminal, setting information used for the relay device to direct a beam toward the user device.

[0007] The communication method according to the third aspect is a method executed by a control terminal that controls a relay device that relays radio signals between a base station and a user device in a mobile communication system. The communication method includes a step of receiving, from the base station, setting information used for the relay device to direct a beam toward the user device, and a step of controlling the relay device to direct the beam toward the user device based on the setting information.

Brief Description of the Drawings

[0008]

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Mode for Carrying Out the Invention

[0009] When controlling a relay device such as a repeater device from a network, the control technology for specifically how to control the relay device has not yet been established, and it is difficult at present to perform efficient coverage expansion using the relay device.

[0010] Therefore, an object of the present disclosure is to enable appropriate control of a relay device that performs relay transmission between a base station and a user device.

[0011] With reference to the drawings, a mobile communication system according to an embodiment will be described. In the description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

[0012] (1) Configuration of Mobile Communication System FIG. 1 is a diagram showing the configuration of a mobile communication system according to an embodiment. The mobile communication system 1 complies with the 5th generation system (5GS) of the 3GPP (registered trademark) standard. Hereinafter, the 5GS will be described as an example, but an LTE (Long Term Evolution) system may be at least partially applied to the mobile communication system. Alternatively, a 6th generation (6G) system may be at least partially applied to the mobile communication system.

[0013] The mobile communication system 1 includes a user equipment (UE) 100, a 5G radio access network (NG-RAN) 10, and a 5G core network (5GC) 20. Hereinafter, the NG-RAN 10 may be simply referred to as the RAN 10. Also, the 5GC 20 may be simply referred to as the core network (CN) 20.

[0014] UE100 is a mobile wireless communication device. UE100 can be any device as long as it can be used by a user. For example, UE100 can be a mobile phone terminal (including smartphones), a tablet terminal, a notebook PC, a communication module (including a communication card or a chipset), a sensor or a device provided for a sensor, a vehicle or a device provided for a vehicle (Vehicle UE), an aircraft or a device provided for an aircraft (Aerial UE).

[0015] NG-RAN10 includes base stations (referred to as "gNB" in the 5G system) 200. gNB200s are interconnected via the Xn interface which is an interface between base stations. gNB200 manages one or more cells. gNB200 performs wireless communication with UE100 that has established a connection with its cell. gNB200 has functions such as a radio resource management (RRM) function, a routing function for user data (hereinafter simply referred to as "data"), and a measurement control function for mobility control and scheduling. "Cell" is used as a term indicating the smallest unit of a wireless communication area. "Cell" is also used as a term indicating a function or resource for performing wireless communication with UE100. One cell belongs to one carrier frequency (hereinafter simply referred to as "frequency").

[0016] Note that the gNB can also be connected to the EPC (Evolved Packet Core) which is the core network of LTE. The base station of LTE can also be connected to 5GC. The base station of LTE and the gNB can also be connected via an interface between base stations.

[0017] 5GC20 includes an AMF (Access and Mobility Management Function) and a UPF (User Plane Function) 300. The AMF performs various mobility controls for the UE100. The AMF manages the mobility of the UE100 by communicating with the UE100 using NAS (Non-Access Stratum) signaling. The UPF performs data transfer control. The AMF and UPF are connected to the gNB200 via the NG interface, which is an interface between the base station and the core network.

[0018] Figure 2 is a diagram showing the configuration of the protocol stack of the radio interface of the user plane that handles data.

[0019] The radio interface protocol of the user plane has a physical (PHY) layer, a MAC (Medium Access Control) layer, an RLC (Radio Link Control) layer, a PDCP (Packet Data Convergence Protocol) layer, and an SDAP (Service Data Adaptation Protocol) layer.

[0020] The PHY layer performs encoding / decoding, modulation / demodulation, antenna mapping / demapping, and resource mapping / demapping. Data and control information are transmitted between the PHY layer of the UE100 and the PHY layer of the gNB200 via a physical channel. Note that the PHY layer of the UE100 receives downlink control information (DCI) transmitted on the physical downlink control channel (PDCCH) from the gNB200. Specifically, the UE100 performs blind decoding of the PDCCH using a radio network temporary identifier (RNTI) and obtains the DCI that has been successfully decoded as DCI addressed to itself. The DCI transmitted from the gNB200 has CRC parity bits scrambled by the RNTI added to it.

[0021] The MAC layer performs priority control of data, retransmission processing by Hybrid Automatic Repeat reQuest (HARQ), and random access procedures, etc. Between the MAC layer of UE100 and the MAC layer of gNB200, data and control information are transmitted via the transport channel. The MAC layer of gNB200 includes a scheduler. The scheduler determines the transport format (transport block size, modulation and coding scheme (MCS)) for the uplink and downlink and the resource blocks allocated to UE100.

[0022] The RLC layer transmits data to the RLC layer on the receiving side by utilizing the functions of the MAC layer and the PHY layer. Between the RLC layer of UE100 and the RLC layer of gNB200, data and control information are transmitted via the logical channel.

[0023] The PDCP layer performs header compression / expansion, encryption / decryption, etc.

[0024] The SDAP layer performs the mapping between the IP flow, which is the unit for the core network to perform Quality of Service (QoS) control, and the radio bearer, which is the unit for the Access Stratum (AS) to perform QoS control. When the RAN is connected to the EPC, the SDAP may not be necessary.

[0025] Figure 3 is a diagram showing the configuration of the protocol stack of the radio interface in the control plane that handles signaling (control signals).

[0026] The protocol stack of the radio interface in the control plane has a Radio Resource Control (RRC) layer and a Non-Access Stratum (NAS) layer instead of the SDAP layer shown in Figure 4.

[0027] Between the RRC layer of UE100 and the RRC layer of gNB200, RRC signaling for various settings is transmitted. The RRC layer controls the logical channel, transport channel, and physical channel in response to the establishment, re-establishment, and release of radio bearers. When there is a connection (RRC connection) between the RRC of UE100 and the RRC of gNB200, UE100 is in the RRC connected state. When there is no connection (RRC connection) between the RRC of UE100 and the RRC of gNB200, UE100 is in the RRC idle state. When the connection between the RRC of UE100 and the RRC of gNB200 is suspended, UE100 is in the RRC inactive state.

[0028] The NAS layer located above the RRC layer performs session management, mobility management, etc. NAS signaling is transmitted between the NAS layer of UE100 and the NAS layer of AMF300A. Note that UE100 has an application layer etc. in addition to the protocol of the radio interface. Also, the layer below the NAS layer is called the AS layer.

[0029] (2) Application Scenarios of Relay Devices Next, the application scenario of the NCR device, which is a relay device according to the embodiment, will be described. FIGS. 4 and 5 are diagrams showing the application scenario of the NCR device according to the embodiment.

[0030] 5G / NR enables broadband transmission in a high-frequency band compared to 4G / LTE. Since radio signals in a high-frequency band such as the millimeter-wave band or the terahertz band have high directivity, reducing the coverage of gNB200 becomes an issue. In FIG. 4, UE100A may be located outside the coverage area of gNB200, for example, outside the area where a radio signal can be directly received from gNB200. There may be an obstacle between gNB200 and UE100A, and UE100A may be in a state where it cannot communicate with gNB200 in line of sight.

[0031] In an embodiment, a repeater device (500A), which is a type of relay device that relays radio signals between the gNB 200 and the UE 100A, is introduced into the mobile communication system 1. The repeater device (500A) that can be controlled from the network is hereinafter referred to as an NCR (Network-Controlled Repeater) device. Such a repeater device may also be referred to as a smart repeater device.

[0032] For example, the NCR device 500A amplifies a radio signal (radio signal) received from the gNB 200 and transmits it by directional transmission. Specifically, the NCR device 500A receives a radio signal transmitted by the gNB 200 by beamforming. Then, the NCR device 500A amplifies the received radio signal and transmits the amplified radio signal by directional transmission. Here, the NCR device 500A may transmit a radio signal with a fixed directivity. Alternatively, the NCR device 500A may transmit a radio signal with a variable (adaptive) directional beam. Thereby, the coverage of the gNB 200 can be efficiently extended. In the embodiment, the case where the NCR device 500A is applied mainly to the downlink communication from the gNB 200 to the UE 100A is assumed, but the NCR device 500A can also be applied to the uplink communication from the UE 100A to the gNB 200.

[0033] Also, as shown in FIG. 5, a new UE (hereinafter referred to as "NCR-UE") 100B, which is a type of control terminal for controlling the NCR device 500A, is introduced. The NCR-UE 100B controls the NCR device 500A in cooperation with the gNB 200 by establishing a radio connection with the gNB 200 and performing radio communication with the gNB 200. Thereby, efficient coverage expansion can be realized using the NCR device 500A. The NCR-UE 100B controls the NCR device 500A according to the control from the gNB 200.

[0034] The NCR-UE100B may be configured separately from the NCR device 500A. For example, the NCR-UE100B may be in the vicinity of the NCR device 500A and electrically connected to the NCR device 500A. The NCR-UE100B may be connected to the NCR device 500A by wire or wirelessly. Alternatively, the NCR-UE100B may be configured integrally with the NCR device 500A. The NCR-UE100B and the NCR device 500A may be fixedly installed, for example, at the coverage edge (cell edge) of the base station 200, or on the wall or window of some building. The NCR-UE100B and the NCR device 500A may be installed on a vehicle or the like and may be movable. Also, one NCR-UE100B may control a plurality of NCR devices 500A.

[0035] In the example shown in FIG. 5, the NCR device 500A dynamically or quasi-statically changes the beam to be transmitted or received. For example, the NCR device 500A forms a beam toward each of the UE100A1 and the UE100A2. Also, the NCR device 500A may form a beam toward the gNB200. For example, in the communication resource between the gNB200 and the UE100A1, the NCR device 500A transmits, by beamforming, the radio signal received from the gNB200 toward the UE100A1, and / or transmits, by beamforming, the radio signal received from the UE100A1 toward the gNB200. In the communication resource between the gNB200 and the UE100A2, the NCR device 500A transmits, by beamforming, the radio signal received from the gNB200 toward the UE100A2, and / or transmits, by beamforming, the radio signal received from the UE100A2 toward the gNB200. Instead of or in addition to beam formation, the NCR device 500A may form a null (so-called null steering) toward a UE100 (not shown) that is not a communication partner and / or an adjacent gNB200 (not shown) for interference suppression. Hereinafter, beam (beamforming) may be read as null (null steering). Alternatively, beam (beamforming) may be read as beam and null (beamforming and null steering).

[0036] FIG. 6 is a diagram showing a configuration example of a protocol stack in a mobile communication system 1 having an NCR device 500A and an NCR-UE 100B according to an embodiment.

[0037] As shown in FIG. 6, the NCR device 500A relays radio signals transmitted and received between the gNB 200 and the UE 100A. The NCR device 500A has an RF (Radio Frequency) function of amplifying and relaying the received radio signals, and performs directional transmission by beamforming (for example, analog beamforming).

[0038] The NCR-UE 100B has at least one layer (entity) among PHY, MAC, RRC, and F1-AP (Application Protocol). F1-AP is a type of front-haul interface. The NCR-UE 100B exchanges downlink signaling and / or uplink signaling with the gNB 200 through at least one of PHY, MAC, RRC, and F1-AP. If the NCR-UE 100B is a type or part of a base station, the NCR-UE 100B may communicate with the gNB 200 through the Xn-AP (Xn-AP) which is an interface between base stations.

[0039] (3) Configuration Example of Control Terminal and Relay Device Next, the configurations of the NCR-UE 100B (control terminal) and the NCR device 500A (relay device) according to the embodiment will be described. FIG. 7 is a diagram showing a configuration example of the NCR-UE 100B and the NCR device 500A according to the embodiment.

[0040] As shown in FIG. 7, the NCR-UE 100B includes a receiving unit 110, a transmitting unit 120, a control unit 130, and an interface 140.

[0041] The receiving unit 110 performs various receptions under the control of the control unit 130. The receiving unit 110 includes an antenna and a receiver. The receiver converts the radio signal (radio signal) received by the antenna into a baseband signal (received signal) and outputs it to the control unit 130. The transmitting unit 120 performs various transmissions under the control of the control unit 130. The transmitting unit 120 includes an antenna and a transmitter. The transmitter converts the baseband signal (transmitted signal) output by the control unit 130 into a radio signal and transmits it from the antenna.

[0042] The control unit 130 performs various controls in the NCR-UE 100B. The control unit 130 includes at least one processor and at least one memory. The memory stores programs executed by the processor and information used for the processing by the processor. The processor may include a baseband processor and a CPU (Central Processing Unit). The baseband processor performs modulation / demodulation and encoding / decoding of the baseband signal, etc. The CPU executes the programs stored in the memory to perform various processes. Also, the control unit 130 executes the functions of at least one layer of PHY, MAC, RRC, and F1-AP.

[0043] The interface 140 is electrically connected to the NCR device 500A. The control unit 130 controls the NCR device 500A via the interface 140. When the NCR-UE 100B and the NCR device 500A are integrally configured, the NCR-UE 100B may not have the interface 140. Also, the receiving unit 110 and the transmitting unit 120 of the NCR-UE 100B may be integrally configured with the radio unit 510A of the NCR device 500A.

[0044] The NCR device 500A includes a wireless unit 510A and an NCR control unit 520A. The wireless unit 510A includes an antenna unit 510a including a plurality of antennas, an RF circuit 510b including an amplifier, and a directivity control unit 510c for controlling the directivity of the antenna unit 510a. The RF circuit 510b amplifies and relays (transmits) the radio signal transmitted and received by the antenna unit 510a. The RF circuit 510b may convert the radio signal, which is an analog signal, into a digital signal, and then reconvert it into an analog signal after digital signal processing. The directivity control unit 510c may perform analog beamforming by analog signal processing, digital beamforming by digital signal processing, or analog and digital hybrid beamforming.

[0045] The NCR control unit 520A controls the wireless unit 510A according to the control signal from the control unit 130 of the NCR-UE100B. The NCR control unit 520A may include at least one processor. The NCR control unit 520A may output information regarding the capabilities of the NCR device 500A to the NCR-UE100B. When the NCR-UE100B and the NCR device 500A are integrally configured, the control unit 130 of the NCR-UE100B and the NCR control unit 520A of the NCR device 500A may also be integrally configured.

[0046] In an embodiment, the receiving unit 110 of the NCR-UE100B receives, by wireless communication from the gNB200, signaling (downlink signaling) used for controlling the NCR device 500A. The control unit 130 of the NCR-UE100B controls the NCR device 500A based on the signaling. Thereby, the gNB200 can control the NCR device 500A via the NCR-UE100B.

[0047] In an embodiment, the control unit 130 of the NCR-UE 100B controls the NCR device 500A. The control unit 130 of the NCR-UE 100B acquires NCR capability information indicating the capabilities of the NCR device 500A from the NCR device 500A (NCR control unit 520A). Then, the transmission unit 120 of the NCR-UE 100B transmits the acquired NCR capability information to the gNB 200 by wireless communication. The NCR capability information is an example of uplink signaling from the NCR-UE 100B to the gNB 200. Thereby, the gNB 200 can grasp the capabilities of the NCR device 500A.

[0048] (4) Configuration example of base station Next, the configuration of the gNB 200 (base station) according to the embodiment will be described. FIG. 8 is a diagram showing a configuration example of the gNB 200 according to the embodiment.

[0049] As shown in FIG. 8, the gNB 200 includes a transmission unit 210, a reception unit 220, a control unit 230, and a backhaul communication unit 240.

[0050] The transmission unit 210 performs various transmissions under the control of the control unit 230. The transmission unit 210 includes an antenna and a transmitter. The transmitter converts the baseband signal (transmission signal) output by the control unit 230 into a radio signal and transmits it from the antenna. The reception unit 220 performs various receptions under the control of the control unit 230. The reception unit 220 includes an antenna and a receiver. The receiver converts the radio signal received by the antenna into a baseband signal (reception signal) and outputs it to the control unit 230. The transmission unit 210 and the reception unit 220 may be capable of beamforming using a plurality of antennas.

[0051] The control unit 230 performs various controls in the gNB 200. The control unit 230 includes at least one processor and at least one memory. The memory stores programs executed by the processor and information used for the processing by the processor. The processor may include a baseband processor and a CPU. The baseband processor performs modulation / demodulation and encoding / decoding of baseband signals, etc. The CPU executes programs stored in the memory to perform various processes.

[0052] The backhaul communication unit 240 is connected to an adjacent base station via a base station interface. The backhaul communication unit 240 is connected to the AMF / UPF 300 via a base station-core network interface. Note that the gNB is composed of a CU (Central Unit) and a DU (Distributed Unit) (i.e., functionally split), and the two units may be connected by an F1 interface.

[0053] In an embodiment, the transmission unit 210 of the gNB 200 transmits, by wireless communication, signaling (downlink signaling) used for controlling the NCR device 500A to the NCR-UE 100B that controls the NCR device 500A. Thereby, the gNB 200 can control the NCR device 500A via the NCR-UE 100B.

[0054] In an embodiment, the reception unit 220 of the gNB 200 receives, by wireless communication, NCR capability information indicating the capabilities of the NCR device 500A from the NCR-UE 100B that controls the NCR device 500A. The NCR capability information is an example of uplink signaling from the NCR-UE 100B to the gNB 200. Thereby, the gNB 200 can grasp the capabilities of the NCR device 500A.

[0055] (5) An example of an operation scenario Next, an example of an operation scenario of the mobile communication system 1 according to the embodiment will be described.

[0056] (5.1) An example of downlink signaling FIG. 9 is a diagram showing an example of downlink signaling from gNB 200 to NCR-UE 100B according to the embodiment.

[0057] gNB 200 (transmission unit 210) transmits downlink signaling to NCR-UE 100B. The downlink signaling may be an RRC message which is signaling of the RRC layer (i.e., layer 3). The downlink signaling may be a MAC CE (Control Element) which is signaling of the MAC layer (i.e., layer 2). The downlink signaling may be downlink control information (DCI) which is signaling of the PHY layer (i.e., layer 1). The downlink signaling may be UE individual signaling or broadcast signaling. The downlink signaling may be a fronthaul message (e.g., an F1-AP message). When NCR-UE 100B is a type or part of a base station, NCR-UE 100B may communicate with gNB 200 via an Xn AP (Xn-AP) which is an interface between base stations.

[0058] For example, as shown in FIG. 9, the gNB 200 (transmission unit 210) transmits an NCR control signal for designating the operating state of the NCR device 500A to the NCR-UE 100B that has established a radio connection with the gNB 200 (step S1). In the following embodiments, an example in which the NCR control signal for designating the operating state of the NCR device 500A is a MAC CE that is signaling at the MAC layer (layer 2) or DCI that is signaling at the PHY layer (layer 1) will be mainly described. However, an NCR control signal may be included in an RRC Reconfiguration message, which is a type of RRC message for each UE, and transmitted to the NCR-UE 100B. The downlink signaling may be a message of a layer higher than the RRC layer (for example, the NCR application). The downlink signaling may encapsulate a message of a layer higher than the RRC layer and transmit it as a message of a layer below the RRC layer. Note that the NCR-UE 100B (transmission unit 120) may transmit an uplink response message to the downlink signaling from the gNB 200. The response message may be transmitted in response to the NCR device 500A completing or receiving the setting specified by the downlink signaling.

[0059] As shown in FIG. 10, the NCR control signal may include frequency control information for designating the center frequency of a radio signal (for example, a component carrier) to be relayed by the NCR device 500A. When the NCR control signal received by the NCR-UE 100B (control unit 130) includes frequency control information, the NCR-UE 100B controls the NCR device 500A to relay the radio signal having the center frequency indicated by the frequency control information (step S2). The NCR control signal may include a plurality of pieces of frequency control information designating different center frequencies. By including the frequency control information in the NCR control signal, the gNB 200 can specify, via the NCR-UE 100B, the center frequency of the radio signal to be relayed by the NCR device 500A.

[0060] The NCR control signal may include mode control information that specifies the operation mode of the NCR device 500A. The mode control information may be associated with frequency control information (center frequency). The operation mode may be any one of a mode in which the NCR device 500A performs omnidirectional transmission and / or reception, a mode in which the NCR device 500A performs fixed-directional transmission and / or reception, a mode in which the NCR device 500A performs transmission and / or reception using a variable-directional beam, and a mode in which the NCR device 500A performs MIMO (Multiple Input Multiple Output) relay transmission. The operation mode may be any one of a beamforming mode (i.e., a mode that emphasizes desired wave improvement) and a null steering mode (i.e., a mode that emphasizes interference wave suppression). When the NCR control signal received by the NCR-UE100B (control unit 130) from the gNB200 includes mode control information, the NCR device 500A is controlled to operate in the operation mode indicated by the mode control information (step S2). By including the mode control information in the NCR control signal, the gNB200 can specify the operation mode of the NCR device 500A via the NCR-UE100B.

[0061] Here, the mode in which the NCR device 500A performs omnidirectional transmission and / or reception is a mode in which the NCR device 500A performs relay in all directions and may be referred to as the omnidirectional mode.

[0062] The mode in which the NCR device 500A performs fixed-directional transmission and / or reception may be a directional mode realized by one directional antenna. Alternatively, the mode may be a beamforming mode realized by applying fixed phase and amplitude control (antenna weight control) to a plurality of antennas. Any of these modes may be specified (set) by the gNB200 for the NCR-UE100B.

[0063] The mode in which the NCR device 500A performs transmission and / or reception using a variable directivity beam may be a mode of performing analog beamforming, a mode of performing digital beamforming, or a mode of performing hybrid beamforming. The mode may also be a mode of forming an adaptive beam specific to the UE100A. Any of these modes may be specified (configured) by the gNB200 for the NCR-UE100B.

[0064] In addition, in the operation mode of performing beamforming, the beam control information described later may be provided from the gNB200 to the NCR-UE100B.

[0065] The mode in which the NCR device 500A performs MIMO relay transmission may be a mode of performing SU (Single-User) spatial multiplexing, a mode of performing MU (Multi-User) spatial multiplexing, or a mode of performing transmit diversity. Any of these modes may be specified (configured) by the gNB200 for the NCR-UE100B.

[0066] The operation mode may include a mode of turning on (activating) the relay transmission by the NCR device 500A and a mode of turning off (deactivating) the relay transmission by the NCR device 500A. Any of these modes may be specified (configured) for the NCR-UE100B by the gNB200 using an NCR control signal.

[0067] The NCR control signal may include beam control information that specifies the transmission direction, transmission weight, or beam pattern when the NCR device 500A performs directional transmission. The beam control information may be associated with frequency control information (center frequency). The beam control information may include a PMI (Precoding Matrix Indicator). When the NCR control signal received by the NCR-UE 100B (control unit 130) includes beam control information, the NCR device 500A is controlled to form the transmission directivity (beam) indicated by the beam control information (step S2). By including the beam control information in the NCR control signal, the gNB 200 can control the transmission directivity of the NCR device 500A via the NCR-UE 100B.

[0068] The NCR control signal may include output control information that specifies the degree of amplification (amplification gain) or transmission power when the NCR device 500A amplifies a radio signal. The output control information may be information indicating the difference value (i.e., relative value) between the current amplification gain or transmission power and the target amplification gain or transmission power. When the NCR control signal received by the NCR-UE 100B (control unit 130) includes output control information, the NCR device 500A is controlled to change to the amplification gain or transmission power indicated by the output control information (step S2). The output control information may be associated with frequency control information (center frequency). The output control information may be information that specifies any one of the amplifier gain, beamforming gain, and antenna gain of the NCR device 500A. The output control information may be information that specifies the transmission power of the NCR device 500A.

[0069] When one NCR-UE100B controls a plurality of NCR devices 500A, the gNB200 (transmission unit 210) may transmit an NCR control signal to the NCR-UE100B for each NCR device 500A. In this case, the NCR control signal may include an identifier of the corresponding NCR device 500A (NCR identifier). The NCR-UE100B (control unit 130) that controls a plurality of NCR devices 500A determines the NCR device 500A to which the NCR control signal is to be applied based on the NCR identifier included in the NCR control signal received from the gNB200. Note that even when the NCR-UE100B controls only one NCR device 500A, the NCR identifier may be transmitted from the NCR-UE100B to the gNB200 together with the NCR control signal.

[0070] In this way, the NCR-UE100B (control unit 130) controls the NCR device 500A based on the NCR control signal from the gNB200. Thereby, the gNB200 can control the NCR device 500A via the NCR-UE100B.

[0071] (5.2) An example of uplink signaling FIG. 11 is a diagram showing an example of uplink signaling from the NCR-UE100B to the gNB200 according to the embodiment.

[0072] The NCR-UE100B (transmission unit 210) transmits uplink signaling to the gNB200. The uplink signaling may be an RRC message, which is signaling at the RRC layer. The uplink signaling may also be a MAC CE, which is signaling at the MAC layer. The uplink signaling may also be uplink control information (UCI), which is signaling at the PHY layer. The uplink signaling may be a fronthaul message (e.g., an F1-AP message) or an inter-base station message (e.g., an Xn-AP message). The uplink signaling may be a message from a layer higher than the RRC layer (e.g., an NCR application). The uplink signaling may encapsulate a message from a layer higher than the RRC layer and transmit it as a message from a layer below the RRC layer. Note that the gNB200 (transmission unit 210) may transmit a response message to the uplink signaling from the NCR-UE100B on the downlink, and the NCR-UE100B (reception unit 110) may receive the response message.

[0073] For example, the NCR-UE100B (transmission unit 120) that has established a radio connection with the gNB200 transmits NCR capability information indicating the capabilities of the NCR device 500A to the gNB200 by wireless communication (step S5). The NCR-UE100B (transmission unit 120) may include the NCR capability information in a UE Capability message or a UE Assistant Information message, which are types of RRC messages, and transmit it to the gNB200. The NCR-UE100B (transmission unit 120) may transmit the NCR capability information (NCR capability information and / or operating status information) to the gNB200 in response to a request or inquiry from the gNB200.

[0074] As shown in FIG. 12, the NCR capability information may include corresponding frequency information indicating the frequency to which the NCR device 500A corresponds. The corresponding frequency information may be a numerical value or an index indicating the center frequency of the frequency to which the NCR device 500A corresponds. Alternatively, the corresponding frequency information may be a numerical value or an index indicating the range of the frequency to which the NCR device 500A corresponds. When the NCR capability information received from the NCR-UE 100B by the gNB 200 (control unit 230) includes the corresponding frequency information, the gNB 200 (control unit 230) can grasp the frequency to which the NCR device 500A corresponds based on the corresponding frequency information. Then, the gNB 200 (control unit 230) may set the center frequency of the radio signal targeted by the NCR device 500A within the range of the frequency to which the NCR device 500A corresponds.

[0075] The NCR capability information may include mode capability information regarding the operation modes that the NCR device 500A can support or the switching between operation modes. As described above, the operation modes include at least one of the mode in which the NCR device 500A performs omnidirectional transmission and / or reception, the mode in which the NCR device 500A performs fixed-directional transmission and / or reception, the mode in which the NCR device 500A performs transmission and / or reception using a variable-directional beam, and the mode in which the NCR device 500A performs MIMO (Multiple Input Multiple Output) relay transmission. The operation mode may be either a beamforming mode (i.e., a mode that emphasizes improving the desired wave) or a null steering mode (i.e., a mode that emphasizes suppressing the interference wave). The mode capability information may be information indicating which of these operation modes the NCR device 500A can support. The mode capability information may be information indicating between which of these operation modes mode switching is possible. When the NCR capability information received from the NCR-UE 100B includes mode capability information, the gNB 200 (control unit 230) can grasp the operation mode and mode switching that the NCR device 500A supports based on the mode capability information. Then, the gNB 200 (control unit 230) may set the operation mode of the NCR device 500A within the grasped operation mode and mode switching range.

[0076] The NCR capability information may include beam capability information indicating the beam variable range, beam variable resolution, or the number of variable patterns when the NCR device 500A performs transmission and / or reception using a variable directional beam. The beam capability information may be, for example, information indicating the variable range of the beam angle (e.g., controllable within 30° to 90°) based on the horizontal or vertical direction, or information indicating the absolute angle. The beam capability information may be represented by the azimuth and / or elevation angle at which the beam is directed. The beam capability information may be information indicating the angle change for each variable step (e.g., 5° / step horizontally, 10° / step vertically). Alternatively, the beam capability information may be information indicating the number of variable steps (e.g., 10 steps horizontally, 20 steps vertically). The beam capability information may be information indicating the number of variable patterns of the beam in the NCR device 500A (e.g., a total of 10 patterns from beam pattern 1 to 10). When the NCR capability information received from the NCR-UE 100B by the gNB 200 (control unit 230) includes the beam capability information, the gNB 200 can grasp the beam angle change or beam pattern that the NCR device 500A can support based on the beam capability information. Then, the gNB 200 (control unit 230) may set the beam of the NCR device 500A within the grasped range of the beam angle change or beam pattern. These beam capability information may be null capability information. In the case of null capability information, it indicates the null control capability when null steering is performed.

[0077] The NCR capability information may include control delay information indicating the control delay time in the NCR device 500A. For example, the control delay information is information indicating the delay time (e.g., 1 ms, 10 ms, etc.) from the timing when the UE 100 receives the NCR control signal or the timing when the setting completion for the NCR control signal is transmitted to the gNB 200 until the control (change of the operation mode, change of the beam) according to the NCR control signal is completed. When the NCR capability information received from the NCR-UE 100B by the gNB 200 (control unit 230) includes the control delay information, the gNB 200 can grasp the control delay time in the NCR device 500A based on the control delay information.

[0078] The NCR capability information may include amplification characteristic information regarding the amplification characteristics or output power characteristics of the radio signals in the NCR device 500A. The amplification characteristic information may be information indicating the amplifier gain (dB), beamforming gain (dB), and antenna gain (dBi) of the NCR device 500A. The amplification characteristic information may be information indicating the variable amplification range (e.g., 0 dB to 60 dB) in the NCR device 500A. The amplification characteristic information may be information indicating the number of steps of the variable amplification degree (e.g., 10 steps) that the NCR device 500A can change, or the amplification degree per variable step (e.g., 10 dB / step). The amplification characteristic information may be information indicating the variable range of the output power (e.g., 0 dBm to 30 dBm) of the NCR device 500A. The amplification characteristic information may be information indicating the number of steps of the output power that the NCR device 500A can change (e.g., 10 steps), or the output power per variable step (e.g., 10 dBm / step).

[0079] The NCR capability information may include location information indicating the installation location of the NCR device 500A. The location information may include any one or more of latitude, longitude, and altitude. The location information may include information indicating the distance and / or installation angle of the NCR device 500A with respect to the gNB 200. The installation angle may be a relative angle with respect to the gNB 200, or may be a relative angle with respect to, for example, north, vertical, or horizontal. The installation location may be the location information of the place where the antenna unit 510a of the NCR device 500A is installed.

[0080] The NCR capability information may include antenna information indicating the number of antennas of the NCR device 500A. The antenna information may be information indicating the number of antenna ports of the NCR device 500A. The antenna information may be information indicating the degree of freedom of directivity control (beam or null formation). The degree of freedom indicates how many beams can be formed (controlled), and is usually "(number of antennas) - ”. For example, in the case of two antennas, the degree of freedom is 1. In the case of two antennas, a figure-eight beam pattern is formed, but since directivity control can be performed in only one direction, the degree of freedom is 1.

[0081] When the NCR-UE100B controls a plurality of NCR devices 500A, the NCR-UE100B (transmission unit 120) may transmit NCR capability information to the gNB200 for each NCR device 500A. In this case, the NCR capability information may include an identifier (NCR identifier) of the corresponding NCR device 500A. Further, when the NCR-UE100B controls a plurality of NCR devices 500A, the NCR-UE100B (transmission unit 120) may transmit information indicating at least one of the respective identifiers of the plurality of NCR devices 500A and the number of the plurality of NCR devices 500A. Note that the NCR identifier may be transmitted from the NCR-UE100B to the gNB200 together with the NCR capability information even when the NCR-UE100B controls only one NCR device 500A.

[0082] (5.3) Overall operation example FIG. 13 is a diagram showing an example of the operation of the mobile communication system 1 according to the embodiment.

[0083] In step S11, the NCR-UE100B is in the RRC idle state or the RRC inactive state.

[0084] In step S12, the gNB200 (transmission unit 210) broadcasts NCR support information indicating that the gNB200 supports the NCR-UE100B. For example, the gNB200 (transmission unit 210) broadcasts a system information block (SIB) including the NCR support information. The NCR support information may be information indicating that the NCR-UE100B can access. Alternatively, the gNB200 (transmission unit 210) may broadcast NCR non-support information indicating that the gNB200 does not support the NCR-UE100B. The NCR non-support information may be information indicating that the NCR-UE100B cannot access.

[0085] The NCR-UE100B (control unit 130) that has not established a radio connection with the gNB200 may determine that access to the gNB200 is permitted in response to receiving NCR support information from the gNB200, and perform an access operation to establish a radio connection with the gNB200. The NCR-UE100B (control unit 130) may perform cell reselection considering the gNB200 (cell) that permits access as having the highest priority.

[0086] On the other hand, the NCR-UE100B (control unit 130) that has not established a radio connection with the gNB200 may determine that access (connection establishment) to the gNB200 is not possible when the gNB200 is not broadcasting NCR support information (or is broadcasting NCR non-support information). As a result, the NCR-UE100B can establish a radio connection only with the gNB200 that can handle the NCR-UE100B.

[0087] Note that when the gNB200 is congested, the gNB200 may broadcast access control information for restricting access from the UE100. However, the NCR-UE100B can be regarded as an entity on the network side, different from a normal UE100. Therefore, the NCR-UE100B may ignore the access control information from the gNB200. For example, when the NCR-UE100B (control unit 130) receives NCR support information from the gNB200, it may perform an operation to establish a radio connection with the gNB200 even if the gNB200 is broadcasting access control information. For example, the NCR-UE100B (control unit 130) may not execute (or may ignore) UAC (Unified Access Control). Or, either one or both of the AC / AI (Access Category / Access Identity) used in UAC may use a special value indicating that it is an access of the NCR-UE.

[0088] In step S13, NCR-UE100B (control unit 130) starts a random access procedure for gNB200. In the random access procedure, NCR-UE100B (transmission unit 120) transmits a random access preamble (Msg1) and an RRC message (Msg3) to gNB200. Also, in the random access procedure, NCR-UE100B (reception unit 110) receives a random access response (Msg2) and an RRC message (Msg4) from gNB200.

[0089] In step S14, when establishing a radio connection with gNB200, NCR-UE100B (transmission unit 120) may transmit NCR-UE information indicating that the own UE is an NCR-UE to gNB200. For example, NCR-UE100B (transmission unit 120) includes the NCR-UE information in a message for the random access procedure (e.g., Msg1, Msg3, Msg5) and transmits it to gNB200 during the random access procedure with gNB200. gNB200 (control unit 230) recognizes that the accessed UE100 is NCR-UE100B based on the NCR-UE information received from NCR-UE100B, and can, for example, remove NCR-UE100B from the access restriction target (i.e., accept the access).

[0090] In step S15, NCR-UE100B transitions from the RRC idle state or the RRC inactive state to the RRC connected state.

[0091] In step S16, gNB200 (transmission unit 120) transmits a capability inquiry message for inquiring about the capabilities of NCR-UE100B to NCR-UE100B. NCR-UE100B (reception unit 110) receives the capability inquiry message.

[0092] In step S17, the NCR-UE100B (transmission unit 120) transmits a capability information message including the above-mentioned NCR capability information to the gNB200. The gNB200 (reception unit 220) receives the capability information message. The gNB200 (control unit 230) grasps the capability of the NCR device 500A based on the received capability information message.

[0093] In step S18, the gNB200 (transmission unit 120) transmits an NCR control signal designating the operation state of the NCR device 500A to the NCR-UE100B. The gNB200 (transmission unit 120) may transmit a MAC CE which is signaling of the MAC layer (layer 2) or a DCI which is signaling of the PHY layer (layer 1) to the NCR-UE100B as the NCR control signal. The NCR-UE100B (reception unit 110) receives the NCR control signal.

[0094] In step S19, the NCR-UE100B (control unit 130) controls the NCR device 500A based on the NCR control signal received from the gNB200. The NCR-UE100B (control unit 130) may control the NCR device 500A by notifying the NCR control signal received from the gNB200 to the NCR device 500A (NCR control unit 520A).

[0095] In step S20, the NCR-UE100B (transmission unit 120) may transmit a completion message to the gNB200 when the control (setting change) of the NCR device 500A is completed. Here, the NCR-UE100B (control unit 130) may determine the completion of control based on a notification (feedback) from the NCR device 500A (NCR control unit 520A). The gNB200 (reception unit 220) receives the completion message.

[0096] (6) Outline of beamforming control between relay device and user device Next, the outline of beamforming control between the relay device and the user device according to the embodiment will be described.

[0097] (6.1) In a mobile communication system (mobile communication system 1), a control terminal (NCR-UE100B) that controls a relay device (NCR device 500A) for relaying radio signals between a base station (gNB200) and a user equipment (UE100A) includes a receiving unit (receiving unit 110) that receives, from the base station, setting information used for the relay device to direct a beam toward the user equipment, and a control unit (control unit 130) that controls the relay device to direct the beam toward the user equipment based on the setting information.

[0098] Such setting information is another example of the above-described downlink signaling. The setting information may be information included in the above-described downlink signaling. Although details will be described later, the relay device is not limited to an NCR device and may be a RIS (Reconfigurable Intelligent Surface) device. Also, the control terminal is not limited to an NCR-UE and may be a RIS-UE. In the following embodiments, an example in which the relay device is an NCR device and the control terminal is an NCR-UE will be mainly described.

[0099] (6.2) In the above (6.1), the setting information includes resource setting information indicating a resource necessary for the control terminal to receive an uplink signal from the user equipment. The receiving unit receives the uplink signal from the user equipment using the resource indicated by the resource setting information, and the control unit may control the relay device to direct the beam toward the user equipment according to the received uplink signal.

[0100] (6.3) In the above (6.2), the control unit may estimate a channel state between the control terminal and the user equipment using the received uplink signal, and control the relay device to direct the beam toward the user equipment according to the estimated channel state.

[0101] (6.4) In the above (6.2), the uplink signal includes beam control information, and the control unit acquires the beam control information included in the received uplink signal, and may control the relay device to direct the beam towards the user equipment according to the acquired beam control information.

[0102] (6.5) In any of the above (6.2) to (6.4), the receiving unit may receive an RRC (Radio Resource Control) message including the resource setting information from the base station.

[0103] (6.6) In any of the above (6.2) to (6.5), the resource setting information may include at least one of PUCCH (Physical Uplink Control Channel) setting information indicating the setting of the PUCCH of the user equipment, PUSCH (Physical Uplink Shared Channel) setting information indicating the setting of the PUSCH of the user equipment, SRS (Sounding Reference Signal) setting information indicating the setting of the SRS of the user equipment, and the C-RNTI (Cell Radio Network Temporary Identifier) assigned to the user equipment.

[0104] (6.7) In the above (6.1), the setting information includes mode setting information for switching a control mode related to beamforming among a plurality of control modes, and the control unit may control the relay device to direct the beam towards the user equipment using the control mode set according to the mode setting information.

[0105] (6.8) In the above (6.7), the plurality of control modes may include a base station control mode in which the control terminal controls the relay device according to the control from the base station.

[0106] (6.9) In the above (6.7) or (6.8), the plurality of control modes may include an autonomous control mode in which the control terminal autonomously controls the relay device without being controlled by the base station.

[0107] (6.10) In any of the above (6.7) to (6.9), the plurality of control modes may further include a hybrid control mode that combines control from the base station and autonomous control of the control terminal.

[0108] (6.11) In any of the above (6.7) to (6.10), the plurality of control modes may further include a beam sweeping control mode for sequentially switching the beam direction of the relay device.

[0109] (6.12) In any of the above (6.7) to (6.11), the receiving unit may receive from the base station an RRC (Radio Resource Control) message including the mode setting information, a MAC (Medium Access Control) CE (Control Element) including the mode setting information, or a DCI (Downlink Control Information) including the mode setting information.

[0110] (6.13) In any of the above (6.7) to (6.12), the mode setting information may include information for switching any one of the control mode of beamforming of the relay device, the control mode of timing switching of the relay device, and the control mode of on / off control of the relay device.

[0111] (6.14) In any of the above (6.7) to (6.13), the mode setting information may include information specifying the timing of switching of the control information.

[0112] The base station used in a mobile communication system (mobile communication system 1) having a control terminal (NCR-UE100B) that controls a relay device (NCR device 500A) that relays radio signals between a base station (gNB200) and a user equipment (UE100A) includes a transmission unit (transmission unit 210) that transmits setting information used for the relay device to direct a beam to the user equipment to the control terminal.

[0113] (6.16) A communication method executed by a control terminal (NCR-UE100B) that controls a relay device (NCR device 500A) that relays radio signals between a base station (gNB200) and a user equipment (UE100A) in a mobile communication system (mobile communication system 1) includes a step of receiving, from the base station, setting information used for the relay device to direct a beam to the user equipment, and a step of controlling the relay device to direct the beam to the user equipment based on the setting information.

[0114] (7) Operational examples regarding beamforming between a relay device and a user equipment Next, with reference to FIG. 14, operational examples regarding beamforming between a relay device and a user equipment according to the embodiment will be described.

[0115] As shown in FIG. 14, the NCR device 500A relays radio signals (referred to as "UE signals") between the gNB200 and the UE100A. The UE signals include an uplink signal (referred to as "UE-UL signal") transmitted from the UE100A to the gNB200 and a downlink signal (referred to as "UE-DL signal") transmitted from the gNB200 to the UE100A. The NCR device 500A relays the UE-UL signal from the UE100A to the gNB200 and relays the UE-DL signal from the gNB200 to the UE100A.

[0116] The NCR-UE100B transmits and receives a wireless signal (hereinafter referred to as the "NCR-UE signal") to and from the gNB200. The NCR-UE signal includes an uplink signal transmitted from the NCR-UE100B to the gNB200 (referred to as the "NCR-UE-UL signal") and a downlink signal transmitted from the gNB200 to the NCR-UE100B (referred to as the "NCR-UE-DL signal"). The NCR-UE-UL signal includes the uplink signaling described above. The NCR-UE-DL signal includes the downlink signaling described above.

[0117] Based on the NCR-UE-UL signal from the NCR-UE100B, the gNB200 directs a beam towards the NCR-UE100B. Since the NCR device 500A is co-located with the NCR-UE100B, when the gNB200 directs a beam towards the NCR-UE100B, as a result, the beam will be directed towards both the NCR-UE100B and the NCR device 500A. The gNB200 uses the beam to transmit the NCR-UE-DL signal and the UE-DL signal. The NCR-UE100B receives the NCR-UE-DL signal. Note that the NCR device 500A and the NCR-UE100B may be at least partially integrated. For example, in the NCR device 500A and the NCR-UE100B, functions (such as antennas) for transmitting and receiving or relaying the UE signal and / or the NCR-UE signal are integrated.

[0118] Here, the problem is how the NCR device 500A directs a beam towards the UE100A. In an embodiment, the NCR-UE100B receives from the gNB200 the configuration information used for the NCR device 500A to direct a beam towards the UE100A. The configuration information is the downlink signaling included in the NCR-UE-DL signal. The NCR-UE100B controls the NCR device 500A to direct a beam towards the UE100A based on the configuration information. This facilitates the NCR device 500A to smoothly direct a beam towards the UE100A. In the following, the first and second operation patterns regarding such beamforming control will be described.

[0119] (7.1) First operation pattern In this first operation pattern, the configuration information transmitted from gNB200 to NCR-UE100B includes resource configuration information indicating the resources necessary for NCR-UE100B to receive the UE-UL signal from UE100A. NCR-UE100B receives the UE-UL signal from UE100A using the resources indicated by the resource configuration information, and controls NCR device 500A to direct a beam towards UE100A in response to the received UE-UL signal.

[0120] For example, NCR-UE100B estimates the channel state between NCR-UE100B and UE100A using the received UE-UL signal. NCR-UE100B may estimate the channel state using the reference signal included in the UE-UL signal. The reference signal may be SRS. Alternatively, the reference signal may be a demodulation reference signal (DMRS) included in PUSCH (and PUCCH). The estimation of the channel state may include the estimation of the arrival direction and / or arrival distance of the UE-UL signal. NCR-UE100B controls NCR device 500A to direct a beam towards UE100A according to the estimated channel state.

[0121] The resource configuration information transmitted from gNB200 to NCR-UE100B may include at least one of PUCCH configuration information indicating the configuration of the PUCCH of UE100A, PUSCH configuration information indicating the configuration of the PUSCH of UE100A, SRS configuration information indicating the configuration of the SRS of UE100A, and the C-RNTI assigned to UE100A.

[0122] FIG. 15 is a diagram showing an example of the operation flow of this first operation pattern. In FIG. 15, the non-essential steps are indicated by dashed lines.

[0123] In step S101, gNB200 establishes an RRC connection with UE100A and configures various resources (e.g., PUCCH resources, PUSCH resources, SRS resources, C-RNTI) of UE100A for UE100A. In this stage, relay transmission by the NCR device 500A may not be performed. Alternatively, the configuration of various resources from gNB200 to UE100A may not be performed at this stage, but may be performed in steps S108 to S109 described later.

[0124] In step S102, NCR-UE100B transmits a capability notification (NCR capability information) indicating that it has uplink reception capability to gNB200. gNB200 receives the capability notification (NCR capability information).

[0125] In step S103, gNB200 transmits a message containing resource configuration information indicating the resources required for NCR-UE100B to receive the UE-UL signal from UE100A to NCR-UE100B. NCR-UE100B receives the message. The message may be the same as the downlink signaling described above. For example, the message may be RRC Reconfiguration, MAC CE, or DCI. The resource configuration information includes at least one information element among the following (A1) to (A4).

[0126] (A1) PUCCH configuration The PUCCH configuration is an information element indicating the configuration of the PUCCH resources of UE100A. By NCR-UE100B obtaining such a PUCCH configuration, it becomes possible for NCR-UE100B to receive (and demodulate and decode) the PUCCH of UE100A. For example, NCR-UE100B uses the reference signal included in the PUCCH for channel estimation. NCR-UE100B may obtain the beam control information (e.g., PMI: Precoding Matrix Indicator) included in the PUCCH. Examples of obtaining beam control information will be described later.

[0127] (A2) PUSCH Configuration The PUSCH configuration is an information element indicating the configuration of the PUSCH resources of UE100A. By the NCR-UE100B obtaining such a PUSCH configuration, it becomes possible for the NCR-UE100B to receive (and demodulate and decode) the PUSCH of UE100A. For example, the NCR-UE100B uses the reference signal included in the PUSCH for channel estimation.

[0128] (A3) SRS Configuration The PUSCH configuration is an information element indicating the configuration of the SRS resources of UE100A. By the NCR-UE100B obtaining such an SRS configuration, it becomes possible for the NCR-UE100B to receive (and demodulate) the SRS of UE100A. The NCR-UE100B uses the SRS for channel estimation.

[0129] (A4) C-RNTI The C-RNTI is a temporary identifier assigned by the gNB200 to the UE100A. The C-RNTI may be required when the NCR-UE100B receives (and demodulates) the signals of the above-mentioned respective channels (for example, PUCCH, PUSCH). Therefore, by the NCR-UE100B obtaining the C-RNTI of the UE100A, it becomes possible to smooth the reception (and demodulation) of the signals of the above-mentioned respective channels.

[0130] In step S104, the UE100A transmits a UE-UL signal. The NCR device 500A receives the UE-UL signal. The UE-UL signal includes at least one of PUCCH, PUSCH, and SRS. Here, the NCR-UE100B receives the UE-UL signal based on the resource configuration information received from the gNB200 in step S103.

[0131] In step S105, the NCR device 500A relays (transfers) the UE-UL signal received from the UE100A in step S104 to the gNB200. The gNB200 receives the relayed UE-UL signal. The gNB200 performs channel estimation based on the received UE-UL signal and determines the antenna weights towards which the beam is directed to the NCR-UE100B (i.e., the NCR device 500A). The antenna weights may be referred to as a precoding matrix.

[0132] In step S106, the NCR-UE100B performs channel estimation based on the UE-UL signal received from the UE100A in step S104.

[0133] In step S107, the NCR-UE100B controls the beam of the NCR device 500A (beamforming control) using the channel estimation result in step S106. For example, the NCR-UE100B determines the antenna weights towards which the beam is directed to the UE100A and sets the antenna weights to the NCR device 500A.

[0134] In step S108, the gNB200 transmits the UE-DL signal while directing the beam to the NCR-UE100B (NCR device 500A). The NCR device 500A receives the UE-DL signal.

[0135] In step S109, the NCR device 500A relays (transfers) the UE-DL signal received from the gNB200 in step S108 to the UE100A. Here, the NCR device 500A transmits the UE-DL signal while directing the beam to the UE100A according to the beamforming control in step S107.

[0136] In step S110, the UE100A transmits the UE-UL signal. The NCR device 500A receives the UE-UL signal. The NCR device 500A may receive the UE-UL signal using the antenna weights (i.e., the directivity set in step S107) set in step S107.

[0137] In step S111, the NCR device 500A relays (transfers) the UE-UL signal received from the UE100A in step S104 to the gNB200. The gNB200 receives the relayed UE-UL signal.

[0138] FIG. 16 is a diagram showing another example of the operation flow of the first operation pattern. In FIG. 16, steps that are not essential are indicated by broken lines. Here, differences from the operation in FIG. 15 will be described.

[0139] In step S103, the gNB200 transmits a message including resource setting information indicating resources necessary for the NCR-UE100B to receive the UE-UL signal from the UE100A to the NCR-UE100B. The NCR-UE100B receives the message. The message may include channel state information between the gNB200 and the NCR device 500A and / or antenna weight information (precoding matrix information) of the gNB200 in addition to at least one information element of (A1) to (A4) described above.

[0140] In step S131, the UE100A transmits a UE-UL signal including beam control information. The NCR device 500A receives the UE-UL signal. The NCR-UE100B receives the UE-UL signal based on the resource setting information received from the gNB200 in step S103. The UE-UL signal may be a PUCCH. The PUCCH may include a PMI as beam control information. The beam control information is information based on the channel estimation result performed on the UE100A side. Specifically, the beam control information is information reflecting the channel state (including the NCR device 500A) between the gNB200 and the UE100A. The beam control information may be information indicating the antenna weight to which the beam is directed from the NCR device 500A to the UE100A.

[0141] In step S132, NCR-UE100B obtains the antenna weight information included in the UE-UL signal received from UE100A in step S131.

[0142] In step S133, NCR-UE100B controls the beam of NCR device 500A using the antenna weight information obtained in step S132 (beamforming control). For example, NCR-UE100B sets the antenna weight indicated by the antenna weight information to NCR device 500A. Alternatively, when the antenna weight information indicates the channel state between gNB200 and UE100A, NCR-UE100B may also derive the channel state between NCR device 500A and UE100A in consideration of the channel state notified by gNB200 in step S103 (i.e., the channel state between gNB200 and NCR device 500A). NCR-UE100B determines the antenna weight towards which the beam is directed to UE100A using the derived channel state, and sets the antenna weight to NCR device 500A.

[0143] Regarding other operations in FIG. 16, they are the same as those in FIG. 15.

[0144] In this first operation pattern, an example where there is one UE100A to be relayed by NCR device 500A has been described, but there may be multiple UE100A to be relayed by NCR device 500A. NCR-UE100B may perform the operations of this first operation pattern for each of the multiple UE100A. gNB200 may transmit a message including the resource setting information of each of the multiple UE100A to NCR-UE100B in step S103.

[0145] Here, in the message, an index may be assigned to the resource configuration information of each of the plurality of UEs 100A. After transmitting the resource configuration information in step S103, the gNB 200 may transmit an activation command (e.g., DCI or MAC CE) including an index specifying the resource configuration information to be actually applied to the NCR-UE 100B. The NCR-UE 100B may apply the resource configuration information specified by the index in response to receiving the activation command.

[0146] Alternatively, it may be assumed that there are a plurality of UEs 100A to be relayed by the NCR device 500A and the plurality of UEs 100A are in proximity. In such a case, the NCR-UE 100B may perform the operation of the first operation pattern for one UE 100A representing the plurality of UEs 100A. Also, in step S103, the gNB 200 may transmit a message including the resource configuration information of the one UE 100A to the NCR-UE 100B.

[0147] (7.2) Second operation pattern In this second operation pattern, the configuration information transmitted from the gNB 200 to the NCR-UE 100B includes mode configuration information for switching a control mode related to beamforming among a plurality of control modes. The NCR-UE 100B controls the NCR device 500A to direct a beam toward the UE 100A using the control mode set according to the mode configuration information. Such mode configuration information may be transmitted by an RRC message, MAC CE, or DCI. The mode configuration information may be information specifying the control mode after switching to the NCR-UE 100B. Alternatively, the mode configuration information may be information permitting a specific control mode to the NCR-UE 100B.

[0148] Among the plurality of control modes, there may be two or more of a "gNB control mode" in which the NCR-UE 100B controls the NCR device 500A according to the control from the gNB 200, an "autonomous control mode" in which the NCR-UE 100B autonomously controls the NCR device 500A without depending on the control from the gNB 200, a "hybrid control mode" that combines the control from the gNB 200 and the autonomous control of the NCR-UE 100B, and a "beam sweeping control mode" that sequentially switches the beam direction of the NCR device 500A.

[0149] The "gNB control mode" is a mode in which the NCR-UE 100B controls the NCR device 500A based on specific control from the gNB 200. In the "gNB control mode", for example, the gNB 200 sequentially instructs the NCR-UE 100B regarding the beam (antenna weight) to be applied to the NCR-UE 100B by means of DCI or MAC CE.

[0150] The "autonomous control mode" is a mode in which the NCR-UE 100B controls the NCR device 500A autonomously without specific control from the gNB 200. In the "autonomous control mode", for example, the NCR-UE 100B determines the beam (antenna weight) to be applied to the NCR-UE 100B, and the NCR-UE 100B performs beam control of the NCR device 500A. It can be considered that the above-described first operation pattern is a type of "autonomous control mode". In the "autonomous control mode", the NCR-UE 100B may estimate the position of the UE 100A using a sensor such as a proximity radar, and the NCR-UE 100B may perform beam control of the NCR device 500A according to the estimated position.

[0151] The "hybrid control mode" is a mode in which the gNB 200 performs rough control on the NCR device 500A, and the NCR-UE 100B autonomously performs specific control on the NCR device 500A. In the "hybrid control mode", for example, the gNB 200 designates the beam direction (directivity direction) in units of 45 degrees, and the NCR-UE 100B autonomously performs fine adjustment of plus or minus 5 degrees with respect to the 45 degrees.

[0152] The "beam sweeping control mode" is a mode in which the NCR-UE100B sequentially switches the beam direction of the NCR device 500A. For example, the NCR device 500A sequentially switches the beam direction so as to rotate the beam 360 degrees in the horizontal direction. The UE100A detects and responds to a signal from the NCR device 500A in any of the beam directions. As a result, it is possible to estimate the direction in which the UE100A is located. After the direction in which the UE100A is located is estimated, the gNB200 may switch the NCR-UE100B to the "autonomous control mode".

[0153] Here, an example of an information element for switching the "control mode of beamforming" of the NCR device 500A has been described as the mode setting information, but the information element may be diverted for switching other control modes. For example, the mode setting information may include an identifier indicating which of the "control mode of beamforming", "control mode of timing switching", and "control mode of on / off control" is the application target. "Timing switching" is, for example, the switching of the timing between the uplink and the downlink in TDD (Time Division Duplex). "On / off control" is, for example, switching the operation of the NCR device 500A between stop (off) and start (on).

[0154] FIG. 17 is a diagram showing an example of an operation flow of the second operation pattern. In FIG. 17, steps that are not essential are indicated by broken lines.

[0155] In step S201, the gNB200 transmits a message including mode setting information for switching the control mode related to beamforming among a plurality of control modes to the NCR-UE100B. The NCR-UE100B receives the message. The message may be the same message as the above-described downlink signaling. For example, the message may be RRC Reconfiguration, MAC CE, or DCI. The mode setting information includes at least one information element among the following (B1) to (B3).

[0156] (B1) Identifier indicating the applicable object This identifier indicates, for example, any one of "beamforming control mode", "timing switching control mode", and "on / off control mode".

[0157] (B2) Mode identifier This identifier indicates, for example, any one of "gNB control mode", "autonomous control mode", "hybrid control mode", and "beam sweeping control mode". Note that the control mode is not limited to being specified by such explicit identifiers, and NCR-UE100B may determine the control mode based on the settings from gNB200. That is, gNB200 may implicitly indicate the control mode to NCR-UE100B. For example, NCR-UE100B may determine it as the gNB control mode when various settings for the gNB control mode are made, and may determine it as the autonomous control mode when various settings for the autonomous control mode are made.

[0158] (B3) Timing information The timing information indicates, by a period or slot number, etc., the timing when the control mode indicated by the mode identifier is applied or the application is permitted. When a period is specified, periodic mode switching is possible.

[0159] In step S202, NCR-UE100B determines the control mode based on the mode setting information received from gNB200 in step S201. For example, NCR-UE100B may switch the "beamforming control mode" between the "gNB control mode" and the "autonomous control mode".

[0160] In the case of the "gNB control mode", in step S203, gNB200 transmits beam control information for controlling the beam of NCR-UE100B to NCR-UE100B. NCR-UE100B receives the beam control information.

[0161] In step S204, the NCR-UE100B controls the beam of the NCR device 500A according to the control mode determined in step S202 (beamforming control). The subsequent operations are the same as those in the first operation pattern described above.

[0162] (8) Modification Examples of Relay Devices and Control Terminals In the above embodiment, an example of a relay device that relays radio signals between the gNB200 and the UE100 (UE100A) is a repeater device (NCR device 500A) that amplifies and transfers the received radio signals. However, the relay device that relays radio signals between the gNB200 and the UE100 (UE100A) may be a RIS (Reconfigurable Intelligent Surface) device that changes the propagation direction of incident radio waves (radio signals) by reflection or refraction. "NCR" in the above embodiment can be read as "RIS". The RIS can perform beamforming (directivity control) in the same way as the NCR by changing the characteristics of the metamaterial. In the case of the RIS, by controlling the reflection direction and refraction direction of each unit element, it may be possible to change the beam range (distance) in the same way as a lens. For example, a configuration may be adopted in which the reflection direction and refraction direction of each unit element are controlled, and the focus is directed to a nearby UE (the beam is directed) or to a distant UE (the beam is directed).

[0163] The RIS device 500B shown in FIG. 18 is a reflective RIS device 500B. Such a RIS device 500B changes the propagation direction of the incident radio wave by reflecting it. Here, the reflection angle of the radio wave can be variably set. The RIS device 500B reflects the radio wave incident from the gNB 200 toward each of the UEs 100A1 and 100A2. Also, the RIS device 500B may reflect the radio wave incident from each of the UEs 100A1 and 100A2 toward the gNB 200. The RIS device 500B dynamically changes the reflection angle of the radio wave. For example, in the communication resource between the gNB 200 and the UE 100A1, the RIS device 500B reflects the radio wave incident from the gNB 200 toward the UE 100A1 and / or reflects the radio wave incident from the UE 100A1 toward the gNB 200. Here, the communication resource includes resources in the time direction and / or resources in the frequency direction. The RIS device 500B reflects the radio wave incident from the gNB 200 toward the UE 100A2 and / or reflects the radio wave incident from the UE 100A2 toward the gNB 200 in the communication resource between the gNB 200 and the UE 100A2.

[0164] The RIS device 500B shown in FIG. 19 is a transmissive RIS device 500B. Such a RIS device 500B changes the propagation direction of the incident radio wave by refracting the incident radio wave. Here, the refraction angle of the radio wave can be variably set. The RIS device 500B refracts the radio wave incident from the gNB 200 toward each of the UEs 100A1 and 100A2. Further, the RIS device 500B may refract the radio wave incident from each of the UEs 100A1 and 100A2 toward the gNB 200. The RIS device 500B dynamically changes the refraction angle of the radio wave. For example, the RIS device 500B refracts the radio wave incident from the gNB 200 toward the UE 100A1 and / or refracts the radio wave incident from the UE 100A1 toward the gNB 200 in the communication resource between the gNB 200 and the UE 100A1. The RIS device 500B refracts the radio wave incident from the gNB 200 toward the UE 100A2 and / or refracts the radio wave incident from the UE 100A2 toward the gNB 200 in the communication resource between the gNB 200 and the UE 100A2.

[0165] In this modification example, as shown in FIG. 20, a new UE (hereinafter referred to as "RIS-UE") 100C, which is a control terminal for controlling the RIS device 500B, is introduced. The RIS-UE 100C controls the RIS device 500B in cooperation with the gNB 200 by establishing a wireless connection with the gNB 200 and performing wireless communication with the gNB 200. Thereby, while suppressing an increase in installation cost and a decrease in installation freedom regarding the RIS device 500B, efficient coverage expansion can be realized using the RIS device 500B. The RIS-UE 100C controls the RIS device 500B according to the RIS control signal from the gNB 200.

[0166] The RIS-UE 100C may be configured separately from the RIS device 500B. For example, the RIS-UE 100C may be in the vicinity of the RIS device 500B and electrically connected to the RIS device 500B. The RIS-UE 100C may be connected to the RIS device 500B by wire or wirelessly. Alternatively, the RIS-UE 100C may be configured integrally with the RIS device 500B. The RIS-UE 100C and the RIS device 500B may be fixedly installed on, for example, a wall surface or a window. The RIS-UE 100C and the RIS device 500B may be installed on, for example, a vehicle or the like and be movable. Also, one RIS-UE 100C may control a plurality of RIS devices 500B.

[0167] FIG. 21 is a diagram showing the configuration of the RIS-UE 100C and the RIS device 500B according to this modification example. As shown in FIG. 21, the RIS-UE 100C includes a receiving unit 110, a transmitting unit 120, a control unit 130, and an interface 140. Such a configuration is the same as that of the above-described embodiment.

[0168] The RIS device 500B has an RIS 510B and an RIS control unit 520B. The RIS 510B is a metasurface configured using metamaterials. For example, the RIS 510B is configured by arranging very small structures in an array with respect to the wavelength of radio waves, and by making the structures have different shapes depending on the placement location, it is possible to arbitrarily design the direction of the reflected wave and the beam shape. The RIS 510B may be a transparent dynamic metasurface. The RIS 510B is configured by stacking a transparent glass substrate on a transparent metasurface substrate in which a large number of small structures are regularly arranged. By slightly moving the stacked glass substrates, it may be possible to dynamically control three modes: a mode in which incident radio waves are transmitted, a mode in which part of the radio waves are transmitted and part are reflected, and a mode in which all radio waves are reflected.

[0169] The RIS control unit 520B controls the RIS 510B according to the RIS control signal from the control unit 130 of the RIS-UE 100C. The RIS control unit 520B may include at least one processor and at least one actuator. The processor decodes the RIS control signal from the control unit 130 of the RIS-UE 100C and drives the actuator according to the RIS control signal. When the RIS-UE 100C and the RIS device 500B are integrally configured, the control unit 130 of the RIS-UE 100C and the RIS control unit 520B of the RIS device 500B may also be integrally configured.

[0170] (9) Other embodiments The NCR / RIS control information transmitted from the gNB 200 to the NCR-UE 100B or the RIS-UE 100C may be information for controlling the direction and focal length of the beam relayed (output) by the NCR device 500A or the RIS device 500B. The information for controlling the direction is, as described above, for example, the antenna weight. The information for controlling the focal length is information for the NCR device 500A or the RIS device 500B to focus the beam according to the distance between the NCR device 500A or the RIS device 500B and the UE 100A. Such information may be information indicating the distance between the NCR device 500A or the RIS device 500B and the UE 100A. Alternatively, such information may be information indicating the focal length (for example, a focal range such as near or far). The NCR device 500A or the RIS device 500B adjusts the focal length of the beam based on the information. In the case of the RIS device 500B, by controlling the reflection (or refraction) angle of the elements outside the metasurface and the reflection (or refraction) angle of the elements inside at different angles (with a difference), the focal length of the beam is adjusted like a lens.

[0171] In the above embodiments, the frequency control information may include a cell ID for identifying a cell and / or a BWP ID for identifying a bandwidth part (BWP). The BWP refers to a part of the frequency band of a cell.

[0172] Each of the above operation flows can be implemented not only separately and independently, but also by combining two or more operation flows. For example, some steps of one operation flow may be added to another operation flow, or some steps of one operation flow may be replaced with some steps of another operation flow. In each flow, it is not necessarily required to execute all steps, and only some steps may be executed.

[0173] In the above embodiments, an example where the base station is an NR base station (gNB) has been described, but the base station may be an LTE base station (eNB). Further, the base station may be a relay node such as an IAB (Integrated Access and Backhaul) node. The base station may be a DU (Distributed Unit) of an IAB node.

[0174] A program may be provided to cause a computer to execute each process performed by the UE100 (NCR-UE100B, RIS-UE100C) or the gNB200. The program may be recorded on a computer-readable medium. By using a computer-readable medium, it is possible to install the program on a computer. Here, the computer-readable medium on which the program is recorded may be a non-transitory recording medium. The non-transitory recording medium is not particularly limited, and may be, for example, a recording medium such as a CD-ROM or a DVD-ROM. Further, circuits for executing each process performed by the UE100 or the gNB200 may be integrated, and at least a part of the UE100 or the gNB200 may be configured as a semiconductor integrated circuit (chipset, SoC: System on a chip).

[0175] As used in this disclosure, the terms "based on" and "depending on" do not mean "only based on" or "only depending on" unless otherwise specified. The term "based on" means both "only based on" and "at least partially based on". Similarly, the term "depending on" means both "only depending on" and "at least partially depending on". Also, "obtain / acquire" may mean obtaining information from stored information, obtaining information from information received from other nodes, or obtaining the information by generating the information. The terms "include", "comprise", and their variants do not mean only including the listed items, but may mean including only the listed items or including additional items in addition to the listed items. Also, the term "or" used in this disclosure is not intended to be an exclusive disjunction. Further, any reference to an element using designations such as "first", "second", etc. used in this disclosure does not generally limit the quantity or order of those elements. These designations may be used herein as a convenient way to distinguish between two or more elements. Thus, a reference to a first and a second element does not mean that only two elements can be employed there or that the first element must precede the second element in some form. In this disclosure, for example, when articles are added by translation such as a, an, and the in English, these articles are assumed to include plural ones unless the context clearly indicates otherwise.

[0176] As described above in detail with reference to the drawings, the specific configuration is not limited to the above, and various design changes and the like can be made without departing from the gist.

[0177] This application claims the priority of Japanese Patent Application No. 2022-071094 (filed on April 22, 2022), and all of its contents are incorporated into the specification of this application.

[0178] (Appended Note) Append the features related to the above-described embodiments.

[0179] (1) A control terminal for controlling a relay device that relays wireless signals between a base station and a user device in a mobile communication system, a receiving unit that receives, from the base station, setting information used for the relay device to direct a beam toward the user device; and a control unit that controls the relay device to direct the beam toward the user device based on the setting information. Control terminal.

[0180] (2) The setting information includes resource setting information indicating resources necessary for the control terminal to receive an uplink signal from the user device, the receiving unit receives the uplink signal from the user device using the resources indicated by the resource setting information, and the control unit controls the relay device to direct the beam toward the user device according to the received uplink signal. The control terminal according to (1) above.

[0181] (3) The control unit estimates a channel state between the control terminal and the user device using the received uplink signal, and controls the relay device to direct the beam toward the user device according to the estimated channel state. The control terminal according to (1) or (2) above.

[0182] (4) The uplink signal includes beam control information, The control unit acquires the beam control information included in the received uplink signal, and controls the relay device to direct the beam toward the user equipment according to the acquired beam control information. The control terminal according to (2) or (3) above.

[0183] (5) The receiving unit receives an RRC (Radio Resource Control) message including the resource setting information from the base station. The control terminal according to any one of (2) to (4) above.

[0184] (6) The resource setting information includes at least one of PUCCH setting information indicating the setting of the PUCCH (Physical Uplink Control Channel) of the user equipment, PUSCH setting information indicating the setting of the PUSCH (Physical Uplink Shared Channel) of the user equipment, SRS setting information indicating the setting of the SRS (Sounding Reference Signal) of the user equipment, and the C-RNTI (Cell Radio Network Temporary Identifier) assigned to the user equipment. The control terminal according to any one of (2) to (5) above.

[0185] (7) The setting information includes mode setting information for switching a control mode related to beamforming among a plurality of control modes, and the control unit controls the relay device to direct the beam toward the user equipment using the control mode set according to the mode setting information. The control terminal according to any one of (1) to (6) above.

[0186] (8) The plurality of control modes include a base station control mode in which the control terminal controls the relay device according to the control from the base station. The control terminal according to (7) above.

[0187] (9) The plurality of control modes include an autonomous control mode in which the control terminal autonomously controls the relay device without depending on the control from the base station. The control terminal according to (7) or (8) above.

[0188] (10) The plurality of control modes further include a hybrid control mode that combines the control from the base station and the autonomous control of the control terminal. The control terminal according to any one of (7) to (9) above.

[0189] (11) The plurality of control modes further include a beam sweeping control mode for sequentially switching the beam direction of the relay device. The control terminal according to any one of (7) to (10) above.

[0190] (12) The receiving unit receives from the base station an RRC (Radio Resource Control) message including the mode setting information, a MAC (Medium Access Control) CE (Control Element) including the mode setting information, or DCI (Downlink Control Information) including the mode setting information. The control terminal according to any one of (7) to (11) above.

[0191] (13) The mode setting information includes information for switching any one of a control mode of beamforming of the relay device, a control mode of timing switching of the relay device, and a control mode of on / off control of the relay device. The control terminal according to any one of (7) to (12) above.

[0192] (14) The mode setting information includes information specifying the timing of switching the control mode. The control terminal according to any one of (7) to (13) above.

[0193] (15) A base station used in a mobile communication system having a control terminal for controlling a relay device that relays a radio signal between the base station and a user device, Comprising a transmission unit that transmits setting information used for the relay device to direct a beam to the user device to the control terminal. Base station.

[0194] (16) In a mobile communication system Executed by a control terminal that controls a relay device that relays a radio signal between a base station and a user device A communication method , Receiving, from the base station, setting information used for the relay device to direct a beam to the user device; Controlling the relay device to direct the beam to the user device based on the setting information. Communication method.

Explanation of Signs

[0195] 1: Mobile communication system 100: UE 100B: NCR-UE 100C: RIS-UE 110: Receiver 120: Transmitter 130: Control unit 140: Interface 200: gNB 210: Transmitter 220: Receiver 230: Control unit 24: Backhaul communication unit 500A: NCR device 500B: RIS device 510A: Wireless unit 510a: Antenna section 510b: RF circuit 510c: Directivity control section 520A: NCR control section 520B: RIS control section

Claims

1. A control terminal for controlling a relay device that relays a radio signal between a network node and a user device in a mobile communication system, a receiving unit that receives, from the network node, setting information used for the relay device to direct a beam toward the user device, a control unit that controls the relay device to direct the beam toward the user device based on the setting information, and has, the setting information includes mode setting information for switching a control mode related to beamforming among a plurality of control modes, the mode setting information includes an identifier corresponding to each of the plurality of control modes and information indicating a period during which the control mode corresponding to the identifier is applied, the control unit controls the relay device to direct the beam toward the user device using the control mode set according to the mode setting information Control terminal.

2. The plurality of control modes include a network node control mode in which the control terminal controls the relay device according to control from the network node The control terminal according to claim 1.

3. The plurality of control modes include an autonomous control mode in which the control terminal autonomously controls the relay device without depending on control from the network node The control terminal according to claim 1 or 2.

4. The plurality of control modes further include a hybrid control mode that combines control from the network node and autonomous control of the control terminal The control terminal according to claim 1 or 2.

5. The plurality of control modes further include a beam sweeping control mode for sequentially switching the beam direction of the relay device The control terminal according to claim 1 or 2.

6. The receiving unit receives, from the network node, an RRC (Radio Resource Control) message including the mode setting information, a MAC (Medium Access Control) CE (Control Element) including the mode setting information, or a DCI (Downlink Control Information) including the mode setting information The control terminal according to claim 1 or 2.

7. The mode setting information includes information for switching any one of the control mode of beamforming of the relay device, the control mode of timing switching of the relay device, and the control mode of on / off control of the relay device. The control terminal according to claim 1 or 2.

8. The mode setting information includes information for specifying the timing of switching the control mode. The control terminal according to claim 1 or 2.

9. A network node used in a mobile communication system having a control terminal for controlling a relay device that relays a radio signal between a network node and a user device, Comprising a transmission unit that transmits setting information used for the relay device to direct a beam to the user device to the control terminal, The setting information includes mode setting information for switching a control mode related to beamforming between a plurality of control modes, The mode setting information includes an identifier corresponding to each of the plurality of control modes and information indicating a period during which the control mode corresponding to the identifier is applied. Network node.

10. A communication method executed by a control terminal for controlling a relay device that relays a radio signal between a network node and a user device in a mobile communication system, Receiving, from the network node, setting information used for the relay device to direct a beam to the user device, Based on the setting information, controlling the relay device to direct the beam to the user device, The setting information includes mode setting information for switching a control mode related to beamforming between a plurality of control modes, The mode setting information includes an identifier corresponding to each of the plurality of control modes and information indicating a period during which the control mode corresponding to the identifier is applied. Controlling the relay device includes controlling the relay device to direct the beam to the user device using the control mode set according to the mode setting information. Communication method.

11. A chipset for a control terminal for controlling a relay device that relays a radio signal between a network node and a user device in a mobile communication system, A process of receiving, from the network node, setting information used for the relay device to direct a beam to the user device, Based on the setting information, execute a process of controlling the relay device to direct the beam toward the user device; The setting information includes mode setting information for switching a control mode related to beamforming among a plurality of control modes; The mode setting information includes an identifier corresponding to each of the plurality of control modes and information indicating a period during which the control mode corresponding to the identifier is applied; The process of controlling the relay device includes a process of controlling the relay device to direct the beam toward the user device by using the control mode set according to the mode setting information; including; Chipset.

12. In a control terminal that controls a relay device that relays a radio signal between a network node and a user device in a mobile communication system, execute a process of receiving, from the network node, setting information used by the relay device to direct a beam toward the user device; Based on the setting information, execute a process of controlling the relay device to direct the beam toward the user device; The setting information includes mode setting information for switching a control mode related to beamforming among a plurality of control modes; The mode setting information includes an identifier corresponding to each of the plurality of control modes and information indicating a period during which the control mode corresponding to the identifier is applied; The process of controlling the relay device includes a process of controlling the relay device to direct the beam toward the user device by using the control mode set according to the mode setting information; Program.

13. A mobile communication system including a control terminal that controls a relay device that relays a radio signal between a network node and a user device, wherein the control terminal receives, from the network node, setting information used by the relay device to direct a beam toward the user device; Based on the setting information, controls the relay device to direct the beam toward the user device; The setting information includes mode setting information for switching a control mode related to beamforming among a plurality of control modes; The mode setting information includes an identifier corresponding to each of the plurality of control modes and information indicating a period during which the control mode corresponding to the identifier is applied; The control terminal controls the relay device to direct the beam toward the user device using the control mode set according to the mode setting information. Mobile communication system.

Images