Communication control method and control terminal

Abstract

This communication control method is for controlling a relay device that relays a radio signal between a base station and a user device in a time division duplex system, the method comprising: a step for performing a downlink relay operation for relaying a downlink signal from the base station to the user device; a step for performing an uplink relay operation for relaying an uplink signal from the user device to the base station, before or after the downlink relay operation; and a step for switching the downlink relay operation and the uplink relay operation at a predetermined timing in a time section between a downlink time section in which the downlink relay operation is performed and an uplink time section in which the uplink relay operation is performed.

Description

[Technical Field]

[0001] The present disclosure relates to a communication control method and a control terminal used in a mobile communication system. [Background technology]

[0002] In recent years, fifth-generation (5G) mobile communication systems have been attracting attention. NR (New Radio), the radio access technology of 5G systems, is capable of wideband transmission using higher frequency bands than LTE (Long Term Evolution), the fourth-generation radio access technology.

[0003] Radio signals (radio waves) in high frequency bands such as millimeter waves or terahertz waves have a tendency to propagate in a highly directional manner, which poses a problem of reducing the coverage of base stations. To solve this problem, repeater devices, which are a type of relay device that relays radio signals between base stations and user devices and can be controlled from a network, have attracted attention (see, for example, Non-Patent Document 1). Such repeater devices can expand the coverage of base stations while suppressing interference, for example, by amplifying radio signals received from base stations and transmitting them using directional transmission. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] 3GPP contribution: RP-213700, “New SI: Study on NR Network-controlled Repeaters” Summary of the Invention

[0005] A communication control method according to a first aspect is a method for controlling a relay device that relays radio signals between a base station and a user equipment (UE) in a time division duplex system, the communication control method comprising: performing a downlink relay operation to relay a downlink signal from the base station to the UE; performing an uplink relay operation to relay an uplink signal from the UE to the base station after or before the downlink relay operation; and switching between the downlink relay operation and the uplink relay operation at a predetermined timing within a time interval between a downlink time interval in which the downlink relay operation is performed and an uplink time interval in which the uplink relay operation is performed.

[0006] The control terminal according to the second aspect includes a control unit that causes a relay device that relays radio signals between a base station and a user device in a time division duplex system to perform a process of performing a downlink relay operation of relaying a downlink signal from the base station to the user device, a process of performing an uplink relay operation of relaying an uplink signal from the user device to the base station after or before the downlink relay operation, and a process of switching operation between the downlink relay operation and the uplink relay operation at a predetermined timing within the time interval between the downlink time interval in which the downlink relay operation is performed and the uplink time interval in which the uplink relay operation is performed. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a diagram illustrating a configuration of a mobile communication system according to an embodiment. [Figure 2] FIG. 10 is a diagram showing the configuration of a protocol stack of a radio interface of a user plane that handles data. [Figure 3] FIG. 1 is a diagram showing the configuration of a protocol stack of a radio interface of a control plane that handles signaling (control signals). [Figure 4] FIG. 1 is a diagram illustrating an application scenario of an NCR device (relay device) according to an embodiment. [Figure 5]FIG. 1 is a diagram illustrating an application scenario of an NCR device according to an embodiment. [Figure 6] 1 is a diagram illustrating an example of the configuration of a protocol stack in a mobile communication system having an NCR device and an NCR-UE (control terminal) according to an embodiment. [Figure 7] FIG. 2 is a diagram illustrating an example of the configuration of an NCR-UE and an NCR device according to an embodiment. [Figure 8] A diagram showing an example configuration of a gNB (base station) according to an embodiment. [Figure 9] A figure showing an example of downlink signaling from a gNB to an NCR-UE according to an embodiment. [Figure 10] FIG. 2 is a diagram illustrating an example of an NCR control signal according to the embodiment. [Figure 11] A figure showing an example of uplink signaling from an NCR-UE to a gNB according to an embodiment. [Figure 12] FIG. 10 is a diagram illustrating an example of NCR capability information according to the embodiment. [Figure 13] FIG. 2 is a diagram illustrating an example of an operation of the mobile communication system according to the embodiment. [Figure 14] A diagram for explaining the operation of an NCR device relaying radio signals between a gNB and a UE in a TDD system according to an embodiment. [Figure 15] 10A and 10B are diagrams illustrating an example of switching from a UL relay operation to a DL relay operation according to an embodiment. [Figure 16] FIG. 10 is a diagram illustrating an operation switching pattern 1 from DL relay operation to UL relay operation according to the embodiment. [Figure 17] 10 is a diagram illustrating an operation switching pattern 2 from DL relay operation to UL relay operation according to the embodiment. FIG. [Figure 18] FIG. 10 is a diagram illustrating an operation switching pattern 3 from DL relay operation to UL relay operation according to the embodiment. [Figure 19] FIG. 10 is a diagram illustrating an operation switching pattern 3 from DL relay operation to UL relay operation according to the embodiment. [Figure 20]FIG. 10 is a diagram for explaining a RIS device (relay device) according to another embodiment. [Figure 21] FIG. 10 is a diagram for explaining a RIS device according to another embodiment. [Figure 22] FIG. 10 is a diagram for explaining a RIS device according to another embodiment. [Figure 23] FIG. 10 is a diagram for explaining a RIS device according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] When controlling relay devices such as repeater devices from a network, the control technology for specifically controlling the relay devices has not yet been established, and it is currently difficult to efficiently extend coverage using relay devices.

[0009] Therefore, an object of the present disclosure is to appropriately control a relay device that relays radio signals between a base station and a user device.

[0010] A mobile communication system according to an embodiment will be described with reference to the drawings. In the description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

[0011] (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 conforms to the 3GPP standard 5th Generation System (5GS). In the following description, 5GS is used as an example, but the mobile communication system may also be at least partially applied to an LTE (Long Term Evolution) system. Furthermore, the mobile communication system may also be at least partially applied to a 6th Generation (6G) system.

[0012] 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. The 5GC 20 may be simply referred to as the core network (CN) 20.

[0013] The UE 100 is a mobile wireless communication device. The UE 100 may be any device that is used by a user. For example, the UE 100 may be a mobile phone terminal (including a smartphone), a tablet terminal, a laptop PC, a communication module (including a communication card or a chipset), a sensor or a device provided in a sensor, a vehicle or a device provided in a vehicle (Vehicle UE), or an aircraft or a device provided in an aircraft (Aerial UE).

[0014] The NG-RAN 10 includes a base station (called "gNB" in the 5G system) 200. The gNBs 200 are connected to each other via an Xn interface, which is an interface between base stations. The gNB 200 manages one or more cells. The gNB 200 performs wireless communication with a UE 100 that has established a connection with its own cell. The gNB 200 has a radio resource management (RRM) function, a routing function for user data (hereinafter simply referred to as "data"), a measurement control function for mobility control and scheduling, etc. The term "cell" is used to indicate the smallest unit of a wireless communication area. The term "cell" is also used to indicate a function or resource that performs wireless communication with a UE 100. One cell belongs to one carrier frequency (hereinafter simply referred to as "frequency").

[0015] In addition, gNBs can also connect to the Evolved Packet Core (EPC), which is the LTE core network. LTE base stations can also connect to 5GC. LTE base stations and gNBs can also be connected via a base station-to-base station interface.

[0016] The 5GC20 includes an Access and Mobility Management Function (AMF) and a User Plane Function (UPF) 300. The AMF performs various mobility controls for the UE 100. The AMF manages the mobility of the UE 100 by communicating with the UE 100 using NAS (Non-Access Stratum) signaling. The UPF controls data forwarding. The AMF and UPF are connected to the gNB 200 via an NG interface, which is an interface between a base station and a core network.

[0017] FIG. 2 is a diagram showing the configuration of a protocol stack of a radio interface of a user plane that handles data.

[0018] The user plane radio interface protocol includes a physical (PHY) layer, a medium access control (MAC) layer, a radio link control (RLC) layer, a packet data convergence protocol (PDCP) layer, and a service data adaptation protocol (SDAP) layer.

[0019] The PHY layer performs encoding / decoding, modulation / demodulation, antenna mapping / demapping, and resource mapping / demapping. Data and control information are transmitted between the PHY layer of UE100 and the PHY layer of gNB200 via a physical channel. The PHY layer of UE100 receives downlink control information (DCI) transmitted from gNB200 on a physical downlink control channel (PDCCH). Specifically, UE100 performs blind decoding of the PDCCH using a radio network temporary identifier (RNTI) and acquires successfully decoded DCI as DCI addressed to the UE. The DCI transmitted from gNB200 has CRC parity bits scrambled by the RNTI added.

[0020] The MAC layer performs data priority control, retransmission processing using Hybrid Automatic Repeat reQuest (HARQ), random access procedures, etc. Data and control information are transmitted between the MAC layer of UE100 and the MAC layer of gNB200 via transport channels. The MAC layer of gNB200 includes a scheduler, which determines the uplink and downlink transport format (transport block size, modulation and coding scheme (MCS)) and the resource blocks to be allocated to UE100.

[0021] The RLC layer transmits data to the RLC layer on the receiving side using the functions of the MAC layer and PHY layer. Data and control information are transmitted between the RLC layer of the UE 100 and the RLC layer of the gNB 200 via logical channels.

[0022] The PDCP layer performs header compression / decompression, encryption / decryption, etc.

[0023] The SDAP layer maps IP flows, which are the units for Quality of Service (QoS) control by the core network, to radio bearers, which are the units for QoS control by the Access Stratum (AS). Note that if the RAN is connected to the EPC, SDAP is not necessary.

[0024] FIG. 3 is a diagram showing the configuration of a protocol stack of a radio interface of a control plane that handles signaling (control signals).

[0025] The protocol stack of the radio interface of the control plane has a Radio Resource Control (RRC) layer and a Non-Access Stratum (NAS) layer instead of the SDAP layer shown in FIG.

[0026] RRC signaling for various settings is transmitted between the RRC layer of UE100 and the RRC layer of gNB200. The RRC layer controls logical channels, transport channels, and physical channels according 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 an RRC connected state. When there is no connection (RRC connection) between the RRC of UE100 and the RRC of gNB200, UE100 is in an RRC idle state. When the connection between the RRC of UE100 and the RRC of gNB200 is suspended, UE100 is in an RRC inactive state.

[0027] The NAS layer, which is located above the RRC layer, performs session management, mobility management, etc. NAS signaling is transmitted between the NAS layer of the UE 100 and the NAS layer of the AMF 300A. Note that the UE 100 has an application layer and the like in addition to the radio interface protocol. Also, the layer below the NAS layer is called the AS layer.

[0028] (2) Application scenarios for relay devices Next, an application scenario of the NCR device, which is a relay device according to the embodiment, will be described. Figures 4 and 5 are diagrams showing application scenarios of the NCR device according to the embodiment.

[0029] 5G / NR enables broadband transmission using higher frequency bands than 4G / LTE. Radio signals in high frequency bands such as the millimeter wave band or terahertz wave band have high line-of-sight properties, which poses a challenge in reducing the coverage of the gNB 200. In FIG. 4, the UE 100A may be located outside the coverage area of ​​the gNB 200, for example, outside an area where a radio signal can be received directly from the gNB 200. There may be an obstruction between the gNB 200 and the UE 100A, preventing the UE 100A from communicating with the gNB 200 within line-of-sight.

[0030] In the embodiment, a repeater device (500A), which is a type of relay device that relays radio signals between a gNB 200 and a UE 100A and can be controlled from a network, is introduced into the mobile communication system 1. Hereinafter, such a repeater device is referred to as an NCR (Network-Controlled Repeater) device. Such a repeater device may also be referred to as a smart repeater device.

[0031] For example, the NCR device 500A amplifies a radio signal (wireless 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 the radio signal with fixed directivity. Alternatively, the NCR device 500A may transmit the radio signal by a variable (adaptive) directional beam. This enables efficient expansion of the coverage of the gNB 200. In the embodiment, it is mainly assumed that the NCR device 500A is applied to downlink communication from the gNB 200 to the UE 100A, but the NCR device 500A can also be applied to uplink communication from the UE 100A to the gNB 200.

[0032] 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 establishes a wireless connection with the gNB 200 and performs wireless communication with the gNB 200, thereby controlling the NCR device 500A in cooperation with the gNB 200. This enables efficient coverage expansion using the NCR device 500A. The NCR-UE 100B controls the NCR device 500A under control from the gNB 200.

[0033] The NCR-UE 100B may be configured separately from the NCR device 500A. For example, the NCR-UE 100B may be located near the NCR device 500A and electrically connected to the NCR device 500A. The NCR-UE 100B may be connected to the NCR device 500A by wire or wirelessly. Alternatively, the NCR-UE 100B may be configured integrally with the NCR device 500A. The NCR-UE 100B and the NCR device 500A may be fixedly installed, for example, at the coverage edge (cell edge) of the base station 200 or on a wall or window of a building. The NCR-UE 100B and the NCR device 500A may be mobile, installed in a vehicle, for example. Furthermore, one NCR-UE 100B may control multiple NCR devices 500A.

[0034] 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 UE 100A1 and the UE 100A2. The NCR device 500A may also form a beam toward the gNB 200. For example, in the communication resource between the gNB 200 and the UE 100A1, the NCR device 500A transmits a radio signal received from the gNB 200 toward the UE 100A1 by beamforming. And / or, the NCR device 500A transmits a radio signal received from the UE 100A1 toward the gNB 200 by beamforming. In the communication resource between the gNB 200 and the UE 100A2, the NCR device 500A transmits a radio signal received from the gNB 200 toward the UE 100A2 by beamforming. And / or, the NCR device 500A transmits a radio signal received from the UE 100A2 toward the gNB 200 by beamforming. Instead of or in addition to forming a beam, the NCR device 500A may form a null (so-called null steering) toward a UE 100 (not shown) and / or a neighboring gNB 200 (not shown) that is not a communication partner in order to suppress interference waves. Hereinafter, the term "beam (beamforming)" may be read as "null (null steering)." Alternatively, the term "beam (beamforming)" may be read as "beam and null (beamforming and null steering)."

[0035] FIG. 6 is a diagram showing an example of the configuration of a protocol stack in a mobile communication system 1 having an NCR device 500A and an NCR-UE 100B according to the embodiment.

[0036] 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 for amplifying and relaying received radio signals, and performs directional transmission using beamforming (for example, analog beamforming).

[0037] The NCR-UE 100B has at least one layer (entity) of PHY, MAC, RRC, and F1-AP (Application Protocol). The F1-AP is a type of fronthaul interface. The NCR-UE 100B exchanges downlink signaling and / or uplink signaling (described below) with the gNB 200 via 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 exchange with the gNB 200 via an Xn AP (Xn-AP), which is an inter-base station interface.

[0038] (3) Example of the configuration of the 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 an example of the configuration of the NCR-UE 100B and the NCR device 500A according to the embodiment.

[0039] As shown in FIG. 7, NCR-UE 100B includes a receiving unit 110, a transmitting unit 120, a control unit 130, and an interface 140.

[0040] The receiving unit 110 performs various receptions under the control of the control unit 130. The receiving unit 110 includes an antenna and a receiver. The receiver converts a radio signal (wireless 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 a baseband signal (transmitted signal) output by the control unit 130 into a radio signal and transmits it from the antenna.

[0041] 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 in 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 baseband signals. The CPU executes programs stored in the memory to perform various processes. The control unit 130 also performs functions of at least one layer of PHY, MAC, RRC, and F1-AP.

[0042] 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 does not need to have the interface 140. Furthermore, the receiving unit 110 and the transmitting unit 120 of the NCR-UE 100B may be integrally configured with the wireless unit 510A of the NCR device 500A.

[0043] The NCR device 500A includes a radio unit 510A and an NCR control unit 520A. The radio unit 510A includes an antenna unit 510a including multiple antennas, an RF circuit 510b including an amplifier, and a directivity control unit 510c that controls the directivity of the antenna unit 510a. The RF circuit 510b amplifies and relays (transmits) radio signals transmitted and received by the antenna unit 510a. The RF circuit 510b may convert analog radio signals into digital signals and reconvert them to analog signals after digital signal processing. The directivity control unit 510c may perform analog beamforming using analog signal processing. Alternatively, the directivity control unit 510c may perform digital beamforming using digital signal processing. Alternatively, the directivity control unit 510c may perform hybrid analog and digital beamforming.

[0044] The NCR control unit 520A controls the wireless unit 510A in response to a control signal from the control unit 130 of the NCR-UE 100B. The NCR control unit 520A may include at least one processor. The NCR control unit 520A may output information related to the capabilities of the NCR device 500A to the NCR-UE 100B. When the NCR-UE 100B and the NCR device 500A are configured integrally, the control unit 130 of the NCR-UE 100B and the NCR control unit 520A of the NCR device 500A may also be configured integrally.

[0045] In the embodiment, the receiver 110 of the NCR-UE 100B receives signaling (downlink signaling) used to control the NCR device 500A from the gNB 200 via wireless communication. The controller 130 of the NCR-UE 100B controls the NCR device 500A based on the signaling. This enables the gNB 200 to control the NCR device 500A via the NCR-UE 100B.

[0046] In the 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 capability 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. This enables the gNB 200 to grasp the capability of the NCR device 500A.

[0047] (4) Example of base station configuration Next, a configuration of the gNB 200 (base station) according to the embodiment will be described. Fig. 8 is a diagram illustrating an example of the configuration of the gNB 200 according to the embodiment.

[0048] As shown in FIG. 8, the gNB 200 includes a transmitter 210, a receiver 220, a controller 230, and a backhaul communication unit 240.

[0049] The transmitting unit 210 performs various transmissions under the control of the control unit 230. The transmitting unit 210 includes an antenna and a transmitter. The transmitter converts a baseband signal (transmission signal) output by the control unit 230 into a radio signal and transmits it from the antenna. The receiving unit 220 performs various receptions under the control of the control unit 230. The receiving unit 220 includes an antenna and a receiver. The receiver converts a radio signal received by the antenna into a baseband signal (reception signal) and outputs it to the control unit 230. The transmitting unit 210 and the receiving unit 220 may be capable of beamforming using multiple antennas.

[0050] 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 in 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. The CPU executes programs stored in the memory to perform various processes.

[0051] The backhaul communication unit 240 is connected to neighboring base stations via an inter-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 divided), and both units may be connected via an F1 interface.

[0052] In the embodiment, the transmitter 210 of the gNB 200 transmits, via wireless communication, signaling (downlink signaling) used to control the NCR device 500A to the NCR-UE 100B that controls the NCR device 500A. This enables the gNB 200 to control the NCR device 500A via the NCR-UE 100B.

[0053] In an embodiment, the receiver 220 of the gNB 200 receives, via wireless communication, NCR capability information indicating the capability 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. This allows the gNB 200 to grasp the capability of the NCR device 500A.

[0054] (5) Operation of the mobile communication system Next, the operation of the mobile communication system 1 according to the embodiment will be described.

[0055] (5.1) Example of Downlink Signaling FIG. 9 is a diagram showing an example of downlink signaling from the gNB 200 to the NCR-UE 100B according to the embodiment.

[0056] The gNB200 (transmitter 210) transmits downlink signaling to the NCR-UE100B. The downlink signaling may be an RRC message, which is signaling of the RRC layer (i.e., Layer 3). Alternatively, the downlink signaling may be MAC CE (Control Element), which is signaling of the MAC layer (i.e., Layer 2). Alternatively, 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-specific signaling. Alternatively, the downlink signaling may be broadcast signaling. The downlink signaling may be a fronthaul message (e.g., an F1-AP message). If the NCR-UE100B is a type or part of a base station, the NCR-UE100B may communicate with the gNB200 via an Xn AP (Xn-AP), which is an inter-base station interface.

[0057] For example, as shown in FIG. 9 , the gNB 200 (transmitter 210) transmits an NCR control signal specifying the operation state of the NCR device 500A to the NCR-UE 100B that has established a wireless connection with the gNB 200 (step S1). In the following embodiment, an example will be mainly described in which the NCR control signal specifying the operation state of the NCR device 500A is MAC CE, which is signaling of the MAC layer (layer 2), or DCI, which is signaling of the PHY layer (layer 1). However, the NCR control signal may be included in an RRC Reconfiguration message, which is a type of RRC message individual to a 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, an NCR application). The downlink signaling may be a message of a layer higher than the RRC layer encapsulated in a message of a layer lower than the RRC layer and transmitted. The NCR-UE 100B (transmitter 120) may transmit, on the uplink, a response message in response to the downlink signaling from the gNB 200. The response message may be transmitted in response to the NCR device 500A completing the configuration specified in the downlink signaling or receiving the configuration.

[0058] As shown in Fig. 10, the NCR control signal may include frequency control information that specifies the center frequency of a radio signal (e.g., a component carrier) to be relayed by the NCR device 500A. When the NCR control signal received from the gNB 200 includes frequency control information, the NCR-UE 100B (control unit 130) controls the NCR device 500A to relay a radio signal having a center frequency indicated by the frequency control information (step S2). The NCR control signal may include multiple pieces of frequency control information that specify different center frequencies. By including frequency control information in the NCR control signal, the gNB 200 can specify, via the NCR-UE 100B, the center frequency of a radio signal to be relayed by the NCR device 500A.

[0059] The NCR control signal may include mode control information that specifies an 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 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-directivity 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 of a beamforming mode (i.e., a mode that prioritizes improving a desired wave) and a null steering mode (i.e., a mode that prioritizes suppressing interference waves). When the NCR control signal received from the gNB 200 includes mode control information, the NCR-UE 100B (control unit 130) controls the NCR device 500A to operate in the operation mode indicated by the mode control information (step S2). Since the NCR control signal includes mode control information, the gNB200 can specify the operating mode of the NCR device 500A via the NCR-UE100B.

[0060] Here, the mode in which the NCR device 500A performs non-directional transmission and / or reception is a mode in which the NCR device 500A performs relay in all directions, and may be referred to as an omni-mode.

[0061] 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. The mode in which the transmission and / or reception is performed may also be a beamforming mode realized by applying fixed phase and amplitude control (antenna weight control) to multiple antennas. Any of these modes may be specified (set) by the gNB 200 to the NCR-UE 100B.

[0062] The mode in which the NCR device 500A transmits and / or receives using a variable directional beam may be a mode in which analog beamforming is performed. The mode in which the transmission and / or reception is performed may also be a mode in which digital beamforming is performed. The mode in which the transmission and / or reception is performed may also be a mode in which hybrid beamforming is performed. The mode may also be a mode in which an adaptive beam specific to the UE 100A is formed. Any of these modes may be specified (set) by the gNB 200 to the NCR-UE 100B.

[0063] In addition, in an operation mode in which beamforming is performed, beam control information described below may be provided from gNB200 to NCR-UE100B.

[0064] The mode in which the NCR device 500A performs MIMO relay transmission may be a mode in which SU (Single-User) spatial multiplexing is performed. The mode in which the MIMO relay transmission is performed may also be a mode in which MU (Multi-User) spatial multiplexing is performed. The mode in which the MIMO relay transmission is performed may also be a mode in which transmit diversity is performed. Any of these modes may be specified (set) by the gNB 200 to the NCR-UE 100B.

[0065] The operation modes may include a mode in which relay transmission by the NCR device 500A is turned on (activated) and a mode in which relay transmission by the NCR device 500A is turned off (deactivated). Either of these modes may be specified (set) by an NCR control signal from the gNB 200 to the NCR-UE 100B.

[0066] 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 from the gNB 200 includes beam control information, the NCR-UE 100B (control unit 130) controls the NCR device 500A to form the transmission directivity (beam) indicated by the beam control information (step S2). When the NCR control signal includes beam control information, the gNB 200 can control the transmission directivity of the NCR device 500A via the NCR-UE 100B.

[0067] The NCR control signal may include output control information that specifies the degree to which the NCR device 500A amplifies a radio signal (amplification gain) or transmission power. The output control information may be information indicating a difference (i.e., a relative value) between a current amplification gain or transmission power and a target amplification gain or transmission power. When the NCR control signal received from the gNB 200 includes output control information, the NCR-UE 100B (control unit 130) controls the NCR device 500A to change the amplification gain or transmission power 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.

[0068] When one NCR-UE 100B controls multiple NCR devices 500A, the gNB 200 (transmission unit 210) may transmit an NCR control signal to the NCR-UE 100B for each NCR device 500A. In this case, the NCR control signal may include an identifier (NCR identifier) ​​of the corresponding NCR device 500A. The NCR-UE 100B (control unit 130) that controls multiple NCR devices 500A determines the NCR device 500A to which the NCR control signal should be applied, based on the NCR identifier included in the NCR control signal received from the gNB 200. Note that the NCR identifier may be transmitted from the NCR-UE 100B to the gNB 200 together with the NCR control signal, even when the NCR-UE 100B controls only one NCR device 500A.

[0069] In this way, the NCR-UE 100B (control unit 130) controls the NCR device 500A based on the NCR control signal from the gNB 200. This enables the gNB 200 to control the NCR device 500A via the NCR-UE 100B.

[0070] (5.2) Example of uplink signaling FIG. 11 is a diagram showing an example of uplink signaling from the NCR-UE 100B to the gNB 200 according to the embodiment.

[0071] The NCR-UE 100B (transmitting unit 210) transmits uplink signaling to the gNB 200. The uplink signaling may be an RRC message, which is signaling of the RRC layer. Alternatively, the uplink signaling may be MAC CE, which is signaling of the MAC layer. Alternatively, the uplink signaling may be uplink control information (UCI), which is signaling of the PHY layer. The uplink signaling may be a fronthaul message (e.g., an F1-AP message). Alternatively, the uplink signaling may be an inter-base station message (e.g., an Xn-AP message). The uplink signaling may be a message of a layer higher than the RRC layer (e.g., an NCR application). The uplink signaling may be a message of a layer higher than the RRC layer encapsulated in a message of a layer lower than the RRC layer and transmitted. In addition, the gNB200 (transmitter 210) may transmit a response message in response to the uplink signaling from the NCR-UE100B on the downlink, and the NCR-UE100B (receiver 110) may receive the response message.

[0072] For example, the NCR-UE 100B (transmitter 120), which has established a wireless connection with the gNB 200, transmits NCR capability information indicating the capabilities of the NCR device 500A to the gNB 200 via wireless communication (step S5). The NCR-UE 100B (transmitter 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 the message to the gNB 200. The NCR-UE 100B (transmitter 120) may transmit the NCR capability information (NCR capability information and / or operation state information) to the gNB 200 in response to a request or inquiry from the gNB 200.

[0073] As shown in FIG. 12, the NCR capability information may include supported frequency information indicating frequencies supported by the NCR device 500A. The supported frequency information may be a numerical value or an index indicating a center frequency of the frequencies supported by the NCR device 500A. Furthermore, the supported frequency information may be a numerical value or an index indicating a range of frequencies supported by the NCR device 500A. When the NCR capability information received from the NCR-UE 100B includes supported frequency information, the gNB 200 (control unit 230) can ascertain the frequencies supported by the NCR device 500A based on the supported 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 frequencies supported by the NCR device 500A.

[0074] The NCR capability information may include mode capability information related to operation modes that the NCR device 500A can support or switching between operation modes. As described above, the operation mode may be at least 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-directivity 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 either a beamforming mode (i.e., a mode that prioritizes improving a desired wave) or a null steering mode (i.e., a mode that prioritizes suppressing interference waves). The mode capability information may be information indicating which of these operation modes the NCR device 500A can support. The mode capability information may also be information indicating which of these operation modes mode switching is possible between. When the NCR capability information received from the NCR-UE 100B includes mode capability information, the gNB 200 (control unit 230) can determine the operation mode and mode switching supported by the NCR device 500A 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 range of the determined operation mode and mode switching.

[0075] The NCR capability information may include beam capability information indicating the beam variable range, beam variable resolution, or number of variable patterns when the NCR device 500A transmits and / or receives using a variable directional beam. The beam capability information may be, for example, information indicating the variable range of the beam angle based on the horizontal or vertical direction (e.g., controllable from 30° to 90°). The beam capability information may also be information indicating an absolute angle. The beam capability information may be expressed by the direction and / or elevation angle of the beam. The beam capability information may also be information indicating the angle change per variable step (e.g., 5° / step horizontally, 10° / step vertically). The beam capability information may also be information indicating the number of variable steps (e.g., 10 steps horizontally, 20 steps vertically). The beam capability information may also be information indicating the number of variable beam patterns in the NCR device 500A (e.g., beam patterns 1 to 10, a total of 10 patterns). When the NCR capability information received from the NCR-UE 100B includes beam capability information, the gNB 200 (control unit 230) can determine the beam angle change or beam pattern that the NCR device 500A can support based on the beam capability information. The gNB 200 (control unit 230) may then set the beam of the NCR device 500A within the range of the determined beam angle change or beam pattern. The beam capability information may be null capability information. In the case of null capability information, the null capability information indicates the null control capability when null steering is performed.

[0076] The NCR capability information may include control delay information indicating a control delay time in the NCR device 500A. For example, the control delay information is information indicating a delay time (e.g., 1 ms, 10 ms, etc.) from the timing when the UE 100 receives an NCR control signal or the timing when the UE 100 transmits a setting completion notice for the NCR control signal to the gNB 200 until the control (change of operation mode or beam) according to the NCR control signal is completed. When the NCR capability information received from the NCR-UE 100B includes control delay information, the gNB 200 (control unit 230) can ascertain the control delay time in the NCR device 500A based on the control delay information.

[0077] The NCR capability information may include amplification characteristic information relating to the amplification characteristic or output power characteristic of a radio signal in the NCR device 500A. The amplification characteristic information may be information indicating the amplifier gain (dB), beamforming gain (dB), or antenna gain (dBi) of the NCR device 500A. The amplification characteristic information may be information indicating the amplification variable range (e.g., 0 dB to 60 dB) of the NCR device 500A. The amplification characteristic information may be information indicating the number of steps (e.g., 10 steps) of the gain that the NCR device 500A can change, or the amplification per variable step (e.g., 10 dB / step). The amplification characteristic information may be information indicating the variable range (e.g., 0 dBm to 30 dBm) of the output power of the NCR device 500A. The amplification characteristic information may be information indicating the number of steps (e.g., 10 steps) of the output power that the NCR device 500A can change, or the output power per variable step (e.g., 10 dBm / step).

[0078] The NCR capability information may include location information indicating the installation location of the NCR device 500A. The location information may include 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 relative to the gNB 200. The installation angle may be a relative angle with respect to the gNB 200, or may be a relative angle based on, for example, north, vertical, or horizontal. The installation location may be location information of the location where the antenna unit 510a of the NCR device 500A is installed.

[0079] The NCR capability information may include antenna information indicating the number of antennas the NCR device 500A has. The antenna information may be information indicating the number of antenna ports the NCR device 500A has. The antenna information may be information indicating the degrees of freedom of directivity control (beam or null formation). The degrees of freedom indicate how many beams can be formed (controlled) and are usually "(number of antennas) - 1". For example, in the case of two antennas, the degrees of freedom are 1. In the case of two antennas, a beam pattern resembling a figure eight is formed, but the degrees of freedom are 1 because directivity control is possible in only one direction.

[0080] When the NCR-UE 100B controls multiple NCR devices 500A, the NCR-UE 100B (transmission unit 120) may transmit NCR capability information to the gNB 200 for each NCR device 500A. In this case, the NCR capability information may include an identifier (NCR identifier) ​​of the corresponding NCR device 500A. Furthermore, when the NCR-UE 100B controls multiple NCR devices 500A, the NCR-UE 100B (transmission unit 120) may transmit information indicating at least one of the identifiers of the multiple NCR devices 500A and the number of the multiple NCR devices 500A. Note that the NCR identifier may be transmitted from the NCR-UE 100B to the gNB 200 together with the NCR capability information, even when the NCR-UE 100B controls only one NCR device 500A.

[0081] (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.

[0082] In step S11, the NCR-UE 100B is in an RRC idle state or an RRC inactive state.

[0083] In step S12, the gNB200 (transmitter 210) broadcasts NCR support information indicating that the gNB200 supports the NCR-UE100B. For example, the gNB200 (transmitter 210) broadcasts a system information block (SIB) including the NCR support information. The NCR support information may be information indicating that the NCR-UE100B is accessible. Alternatively, the gNB200 (transmitter 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 is not accessible.

[0084] An NCR-UE 100B (control unit 130) that has not established a wireless connection with a gNB 200 may determine, in response to receiving NCR support information from the gNB 200, that access to the gNB 200 is permitted, and may perform an access operation to establish a wireless connection with the gNB 200. The NCR-UE 100B (control unit 130) may perform cell reselection by regarding the gNB 200 (cell) to which access is permitted as having the highest priority.

[0085] On the other hand, if the gNB 200 does not broadcast NCR support information (or broadcasts NCR non-support information), the NCR-UE 100B (control unit 130) that has not established a wireless connection with the gNB 200 may determine that it is unable to access (establish a connection with) the gNB 200. This allows the NCR-UE 100B to establish a wireless connection only with a gNB 200 that can handle the NCR-UE 100B.

[0086] Note that, when the gNB 200 is congested, the gNB 200 may broadcast access restriction information that restricts access from the UE 100. However, unlike a normal UE 100, the NCR-UE 100B can be considered a network-side entity. Therefore, the NCR-UE 100B may ignore the access restriction information from the gNB 200. For example, when the NCR-UE 100B (control unit 130) receives NCR support information from the gNB 200, it may perform an operation to establish a wireless connection with the gNB 200 even if the gNB 200 is broadcasting access restriction information. For example, the NCR-UE 100B (control unit 130) may not execute (or may ignore) UAC (Unified Access Control). Alternatively, a special value indicating that the access is from an NCR-UE may be used as either or both of AC / AI (Access Category / Access Identity) used in UAC.

[0087] In step S13, the NCR-UE 100B (control unit 130) starts a random access procedure for the gNB 200. In the random access procedure, the NCR-UE 100B (transmitting unit 120) transmits a random access preamble (Msg1) and an RRC message (Msg3) to the gNB 200. Also, in the random access procedure, the NCR-UE 100B (receiving unit 110) receives a random access response (Msg2) and an RRC message (Msg4) from the gNB 200.

[0088] In step S14, when establishing a wireless connection with the gNB200, the NCR-UE100B (transmitting unit 120) may transmit NCR-UE information indicating that its own UE is an NCR-UE to the gNB200. For example, during a random access procedure with the gNB200, the NCR-UE100B (transmitting unit 120) transmits to the gNB200 the NCR-UE information included in a message for the random access procedure (e.g., Msg1, Msg3, Msg5). The gNB200 (control unit 230) recognizes that the accessing UE100 is the NCR-UE100B based on the NCR-UE information received from the NCR-UE100B, and can, for example, exclude the NCR-UE100B from the access restriction targets (i.e., accept the access).

[0089] In step S15, the NCR-UE 100B transitions from the RRC idle state or the RRC inactive state to the RRC connected state.

[0090] In step S16, the gNB 200 (transmitter 120) transmits a capability inquiry message to the NCR-UE 100B to inquire about the capability of the NCR-UE 100B. The NCR-UE 100B (receiver 110) receives the capability inquiry message.

[0091] In step S17, the NCR-UE 100B (transmitter 120) transmits a capability information message including the above-mentioned NCR capability information to the gNB 200. The gNB 200 (receiver 220) receives the capability information message. The gNB 200 (controller 230) determines the capability of the NCR device 500A based on the received capability information message.

[0092] In step S18, the gNB 200 (transmitter 120) transmits an NCR control signal specifying the operation state of the NCR device 500A to the NCR-UE 100B. The gNB 200 (transmitter 120) may transmit MAC CE, which is signaling of the MAC layer (layer 2), or DCI, which is signaling of the PHY layer (layer 1), to the NCR-UE 100B as the NCR control signal. The NCR-UE 100B (receiver 110) receives the NCR control signal.

[0093] In step S19, the NCR-UE 100B (control unit 130) controls the NCR device 500A based on the NCR control signal received from the gNB 200. The NCR-UE 100B (control unit 130) may control the NCR device 500A by notifying the NCR control signal received from the gNB 200 to the NCR device 500A (NCR control unit 520A).

[0094] In step S20, when the control (setting change) of the NCR device 500A is completed, the NCR-UE 100B (transmitter 120) may transmit a completion message to the gNB 200. Here, the NCR-UE 100B (controller 130) may determine the completion of the control based on a notification (feedback) from the NCR device 500A (NCR controller 520A). The gNB 200 (receiver 220) receives the completion message.

[0095] (5.4) Operation of control terminals and repeaters in TDD The following describes the operations of the NCR-UE 100B (control terminal) and the NCR device 500A (relay device) when time division duplex (TDD) is applied to the mobile communication system 1. In the following, the downlink is abbreviated as DL and the uplink is abbreviated as UL.

[0096] FIG. 14 is a diagram illustrating an operation of the NCR device 500A to relay radio signals (specifically, DL signals and UL signals) between the gNB 200 and the UE 100A in the TDD system according to the embodiment. In FIG. 14, "DL" represents a DL time interval, "UL" represents a UL time interval, and "Sp" represents a flexible time interval. The DL time interval, the UL time interval, and the flexible time interval may be configured with a plurality of symbols (OFDM symbols) in the time direction. Note that, although an example is shown in which the time length of the DL time interval and the time length of the UL time interval are equal, these time lengths may be different. A slot format including the number of symbols in each of the DL time interval, the UL time interval, and the flexible time interval may be configured by the gNB 200 to the UE 100A and the NCR-UE 100B.

[0097] In NR, one subframe consists of multiple symbols in the time domain. The resource allocation unit is a resource block, which consists of multiple symbols and multiple subcarriers in the frequency domain. A frame can be configured to be 10 ms long and can include 10 subframes, each consisting of 1 ms. A subframe can include a number of slots corresponding to the subcarrier spacing.

[0098] As shown in Figure 14, during the DL time interval from time t0 to t3, gNB200 transmits a DL signal.

[0099] After the propagation delay time from time t0 to t1 has elapsed, in the DL time period from time t1 to t4, the NCR device 500A receives a DL signal from the gNB 200, amplifies the received DL signal, and transmits it to the UE 100A. In this way, in the DL time period from time t1 to t4, the NCR-UE 100B controls the NCR device 500A to perform DL relay operation. Note that the time from t0 to t1 may include not only the propagation delay time but also the internal processing time (processing delay time) of the NCR device 500A.

[0100] After a propagation delay time from time t1 to t2 has elapsed, the UE 100A receives a DL signal from the NCR device 500A in a DL time interval from time t2 to t5.

[0101] In the UL transmission time period from time t6 to time t9, the UE 100A transmits a UL signal to the NCR device 500A. Here, the transmission timing of the UL signal in the UE 100A is adjusted according to a timing advance (TA) managed by the UE 100A. The TA is a value managed by the UE 100A to compensate for propagation delay time. The UE 100A transmits the UL signal ahead of schedule by the time indicated by the TA, based on the DL timing. Note that the UE 100A may update the TA based on a TA command signaled to the UE 100A from the gNB 200.

[0102] After the propagation delay time from time t6 to t7 has elapsed, in the UL time period from time t7 to t10, the NCR device 500A receives a UL signal from the UE 100A, amplifies the received UL signal, and transmits it to the gNB 200. In this way, in the UL time period from time t7 to t10, the NCR-UE 100B controls the NCR device 500A to perform UL relay operation. Here, the NCR-UE 100B may adjust the transmission timing of the UL signal according to the TA managed by the NCR-UE 100B. This TA is a value managed by the NCR-UE 100B to compensate for the propagation delay time. The NCR-UE 100B transmits the UL signal ahead of schedule by the time of the TA, based on the DL timing. Note that the NCR-UE 100B may update the TA based on a TA command signaled from the gNB 200 to the NCR-UE 100B.

[0103] After the propagation delay time from time t7 to t8 has elapsed, in the UL time period from time t8 to t11, the gNB 200 receives the UL signal from the NCR device 500A. Note that the time from t7 to t8 may include not only the propagation delay time but also the internal processing time (processing delay time) of the NCR device 500A.

[0104] During the DL time interval from time t11 to t14, the gNB 200 transmits a DL signal to the NCR device 500A.

[0105] After the propagation delay time from time t11 to t12 has elapsed, in the DL time interval from time t12 to t15, the NCR device 500A receives a DL signal from the gNB 200, amplifies the received DL signal, and transmits it to the UE 100A. In this way, in the DL time interval from time t12 to t15, the NCR-UE 100B controls the NCR device 500A to perform DL relay operation.

[0106] After the propagation delay time from time t12 to t13 has elapsed, the UE 100A receives a DL signal from the NCR device 500A in a DL time interval from time t13 to t16. Note that the time from t12 to t13 may include not only the propagation delay time but also the internal processing time (hardware processing delay time) of the NCR device 500A.

[0107] In this way, the NCR device 500A that relays radio signals between the gNB 200 and the UE 100A in the TDD system alternates between DL relaying operation and UL relaying operation. In the embodiment, the NCR-UE 100B controls the NCR-UE 100B to switch between the DL relaying operation and the UL relaying operation at a predetermined timing within a time interval between a DL time interval in which the DL relaying operation is performed and a UL time interval in which the UL relaying operation is performed. This allows appropriate switching between the DL relaying operation and the UL relaying operation.

[0108] Here, taking into consideration the control delay (e.g., hardware processing delay of NCR device 500A) when NCR-UE 100B controls NCR device 500A, it is preferable that NCR-UE 100B performs operation switching control between DL relay operation and UL relay operation before the last timing (last symbol) in the time interval between the DL time interval and the UL time interval.

[0109] Furthermore, considering the presence of delayed waves due to multipath, etc., it is preferable to control switching between DL relaying and UL relaying after the first timing (first symbol) in the time interval between the DL time interval and the UL time interval, which enables the NCR device 500A to relay delayed waves as well.

[0110] Therefore, the NCR-UE 100B controls the NCR device 500A to switch between the DL relaying operation and the UL relaying operation near the midpoint of the time interval between the DL time interval and the UL time interval, thereby making it possible to appropriately control the NCR device 500A that relays radio signals between the gNB 200 and the UE 100A.

[0111] (5.4.1) Example of switching from UL repeater operation to DL repeater operation First, an example of switching from UL relaying to DL relaying will be described. Fig. 15 is a diagram showing an example of switching from UL relaying to DL relaying according to the embodiment.

[0112] The NCR-UE 100B manages the TA for adjusting the transmission timing of the UL signal from the NCR device 500A to the gNB 200. In this operation switching example, the predetermined timing for controlling operation switching from the UL relaying operation to the DL relaying operation is the timing when the time indicated by the value obtained by dividing the TA by n (n≧2) has elapsed from the end timing of the UL time interval. Here, n=2, but for example, n=3 may also be used. The value obtained by division refers to the division result, and if the division result includes a fraction after the decimal point, for example, the fraction after the decimal point may be truncated or rounded off.

[0113] An example of switching from UL relay operation to DL relay operation will be described using the time interval from time t10 to t12 shown in Fig. 15 as an example. Time t10 corresponds to the end timing of the UL time interval in the NCR device 500A. Here, times t7 to t10 are the UL time interval in the NCR device 500A, and time t10 is the timing of the last symbol in that UL time interval.

[0114] The NCR-UE 100B checks the TA that it manages and calculates "TA÷2." Then, the NCR-UE 100B controls the NCR device 500A to switch operation from UL relaying to DL relaying at the timing when a time equivalent to "TA÷2" has elapsed since time t10 (i.e., time t11).

[0115] By such operation switching control, the NCR device 500A switches its operation from UL relaying operation to DL relaying operation before time t12 when the DL time interval starts. As a result, in the DL time interval from time t12 to t15, the NCR device 500A receives a DL signal from the gNB 200, amplifies the received DL signal, and transmits it to the UE 100A (i.e., DL relaying operation).

[0116] (5.4.2) Example of switching from DL relay operation to UL relay operation Next, operation switching patterns 1 to 3 will be described as examples of switching from DL relaying operation to UL relaying operation.

[0117] Operation switching pattern 1 is a switching pattern that uses TA, similar to the above-mentioned example of switching from UL relaying operation to DL relaying operation. On the other hand, operation switching patterns 2 and 3 are switching patterns that assume the provision of a flexible time interval (Sp) that can be used for switching from the DL time interval to the UL time interval.

[0118] (5.4.2.1) Operation switching pattern 1 FIG. 16 is a diagram illustrating an operation switching pattern 1 from DL relay operation to UL relay operation according to the embodiment.

[0119] An example of switching from DL relaying to UL relaying will be described using the time interval from time t4 to t7 shown in Fig. 16 as an example. Time t4 corresponds to the end timing of the DL time interval in the NCR device 500A. Here, times t1 to t4 are the DL time interval in the NCR device 500A, and time t4 is the timing of the last symbol in the DL time interval.

[0120] The NCR-UE 100B checks the TA that it manages and calculates "TA÷2." Then, the NCR-UE 100B controls the NCR device 500A to switch operation from DL relaying to UL relaying at the timing when a time equivalent to "TA÷2" has elapsed since time t4 (i.e., time t5).

[0121] By such operation switching control, the NCR device 500A switches its operation from DL relaying operation to UL relaying operation before time t12 when the UL time interval starts. As a result, in the UL time interval from time t7 to t10, the NCR device 500A receives a UL signal from the UE 100, amplifies the received UL signal, and transmits it to the gNB 200 (i.e., UL relaying operation).

[0122] (5.4.2.2) Operation switching pattern 2 17 is a diagram showing operation switching pattern 2 from DL relay operation to UL relay operation according to the embodiment. Note that the switching control method of operation switching pattern 2 may be applied to operation switching control from UL relay operation to DL relay operation.

[0123] 17, when the DL time interval, flexible time interval, and UL time interval are consecutive in this order, the symbol numbers of each symbol are assigned as consecutive numbers. Symbol numbers "1" to "10" are the DL time interval, symbol numbers "11" to "17" are the flexible time interval, and symbol numbers "18" to "27" are the UL time interval.

[0124] In this operation switching pattern 2, the predetermined timing for controlling operation switching from DL relaying operation to UL relaying operation is the timing of the midpoint (from another perspective, the midpoint symbol) in the time interval (specifically, the flexible time interval) between the DL time interval and the UL time interval. In the example of Fig. 17, the timing of the midpoint is the timing of symbol number "14". The NCR-UE 100B controls the NCR device 500A to switch operation from UL relaying operation to DL relaying operation at the timing of symbol number "14".

[0125] By such operation switching control, the NCR device 500A switches its operation from DL relaying operation to UL relaying operation before the start of the UL time interval, symbol number 18. As a result, in the UL time interval of symbol numbers 18 to 27, the NCR device 500A receives a UL signal from the UE 100, amplifies the received UL signal, and transmits it to the gNB 200 (i.e., UL relaying operation).

[0126] Note that if the number of symbols in the flexible time interval is odd, it is easy to derive the timing of the midpoint (the symbol at the midpoint). On the other hand, if the number of symbols in the flexible time interval is even, the timing of the midpoint (the symbol at the midpoint) may be derived as follows. For example, if the number of symbols in the flexible time interval is four, the NCR-UE 100B may determine the second symbol of the flexible time interval as the timing of the midpoint (the symbol at the midpoint), or may determine the third symbol of the flexible time interval as the timing of the midpoint (the symbol at the midpoint).

[0127] (5.4.2.3) Operation switching pattern 3 18 and 19 are diagrams illustrating an operation switching pattern 3 from DL relaying operation to UL relaying operation according to the embodiment. The switching control method of this operation switching pattern 3 may be applied to the operation switching control from UL relaying operation to DL relaying operation.

[0128] In the above-described operation switching pattern 2, it is assumed that the NCR-UE 100B determines the predetermined timing according to a predetermined rule. On the other hand, in this operation switching pattern 3, the predetermined timing is a designated timing designated by the gNB 200 within a time interval between the DL time interval and the UL time interval. In other words, the NCR-UE 100B controls the NCR device 500A to switch its operation from UL relaying operation to DL relaying operation at the designated timing designated by the gNB 200.

[0129] For example, as shown in FIG. 18, the gNB 200 transmits designation timing information indicating a symbol number as the designated timing to the NCR-UE 100B. The NCR-UE 100B receives the designation timing information from the gNB 200. The designation timing information is a type of downlink signaling described above, and may be L1 / L2 signaling (e.g., DCI or MAC CE). The designation timing information may also be higher layer signaling (e.g., an RRC message). The symbol number as the designated timing may be a symbol number indicating a position within a slot (the number within the slot). The symbol number may also be a symbol number indicating a position within a flexible time interval (the number within the flexible time interval).

[0130] In step S102, NCR-UE 100B controls NCR device 500A to switch operation from DL relay operation to UL relay operation at the symbol corresponding to the symbol number indicated by the received specified timing information.

[0131] Alternatively, as shown in Fig. 19, the gNB 200 may transmit a DCI (hereinafter referred to as a "switching instruction DCI") instructing the execution of operation switching control to the NCR-UE 100B on the PDCCH at a predetermined timing. The NCR-UE 100B receives the switching instruction DCI from the gNB 200. The switching instruction DCI may be a scheduling DCI that schedules resources. Alternatively, the switching instruction DCI may be a non-scheduling DCI.

[0132] In step S102, the NCR-UE 100B controls the NCR device 500A to switch operation from DL relay operation to UL relay operation at the timing (symbol) at which the NCR-UE 100B receives the switching instruction DCI from the gNB 200.

[0133] (6) Other embodiments In the above-described embodiment, an example has been described in which the relay device that relays radio signals between the gNB 200 and the UE 100 (UE 100A) is a repeater device (NCR device 500A) that amplifies and forwards the received radio signals. However, the relay device that relays radio signals between the gNB 200 and the UE 100 (UE 100A) may also 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-described embodiment can be read as "RIS".

[0134] The RIS device 500B shown in FIG. 20 is a reflection-type RIS device 500B. Such a RIS device 500B changes the propagation direction of an incident radio wave by reflecting the radio wave. 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 UE 100A1 and the UE 100A2. The RIS device 500B may also reflect the radio waves incident from each of the UE 100A1 and the UE 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 a time-direction resource and / or a frequency-direction resource. In the communication resources between gNB200 and UE100A2, RIS device 500B reflects radio waves incident from gNB200 toward UE100A2 and / or reflects radio waves incident from UE100A2 toward gNB200.

[0135] The RIS device 500B shown in FIG. 21 is a transparent RIS device 500B. Such a RIS device 500B changes the propagation direction of an incident radio wave by refracting the 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 UE 100A1 and the UE 100A2. The RIS device 500B may also refract the radio waves incident from each of the UE 100A1 and the UE 100A2 toward the gNB 200. The RIS device 500B dynamically changes the refraction angle of the radio wave. For example, 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 100A1 and / or refracts the radio wave incident from the UE 100A1 toward the gNB 200. In the communication resources between gNB200 and UE100A2, RIS device 500B refracts radio waves incident from gNB200 toward UE100A2 and / or refracts radio waves incident from UE100A2 toward gNB200.

[0136] In this modification, as shown in FIG. 22, a new UE (hereinafter referred to as "RIS-UE") 100C is introduced, which is a control terminal for controlling the RIS device 500B. The RIS-UE 100C establishes a wireless connection with the gNB 200 and performs wireless communication with the gNB 200, thereby controlling the RIS device 500B in cooperation with the gNB 200. This makes it possible to achieve efficient coverage expansion using the RIS device 500B while suppressing increases in installation costs and decreases in installation flexibility for the RIS device 500B. The RIS-UE 100C controls the RIS device 500B in accordance with a RIS control signal from the gNB 200.

[0137] The RIS-UE 100C may be configured separately from the RIS device 500B. For example, the RIS-UE 100C may be located near the RIS device 500B and electrically connected to the RIS device 500B. The RIS-UE 100C may be connected to the RIS device 500B via a wired or wireless connection. 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, for example, on a wall or window. The RIS-UE 100C and the RIS device 500B may be mobile, installed, for example, in a vehicle. Furthermore, one RIS-UE 100C may control multiple RIS devices 500B.

[0138] FIG. 23 is a diagram showing the configuration of the RIS-UE 100C and the RIS device 500B according to the embodiment.

[0139] 23, RIS-UE 100C includes a receiving unit 110, a transmitting unit 120, a control unit 130, and an interface 140. This configuration is similar to that of the above-described embodiment.

[0140] The RIS device 500B includes a RIS 510B and a RIS control unit 520B. The RIS 510B is a metasurface made of metamaterial. For example, the RIS 510B is configured by arranging extremely small structures relative to the wavelength of radio waves in an array. By varying the shape of the structures depending on their placement, it is possible to arbitrarily design the direction and beam shape of the reflected waves. The RIS 510B may be a transparent dynamic metasurface. The RIS 510B may be configured by overlaying a transparent glass substrate on a transparent metasurface substrate on which a large number of small structures are regularly arranged. By minutely moving the overlaid glass substrate, it may be possible to dynamically control three patterns: a mode that transmits incident radio waves, a mode that transmits and reflects some of the radio waves, and a mode that reflects all of the radio waves.

[0141] The RIS control unit 520B controls the RIS 510B in response to a 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 in response to the RIS control signal. Note that when the RIS-UE 100C and the RIS device 500B are configured integrally, the control unit 130 of the RIS-UE 100C and the RIS control unit 520B of the RIS device 500B may also be configured integrally.

[0142] In the above description, the frequency control information may include a cell ID that identifies a cell and / or a BWP ID that identifies a bandwidth portion (BWP). A BWP refers to a frequency band that is part of a cell.

[0143] The above-described operational flows are not limited to being implemented independently, but can also be implemented by combining two or more operational flows. For example, some steps of one operational flow may be added to another operational flow, or some steps of one operational flow may be replaced with some steps of another operational flow. In each flow, it is not necessary to execute all steps, and only some steps may be executed.

[0144] In the above embodiment, an example in which the base station is an NR base station (gNB) has been described, but the base station may also be an LTE base station (eNB). The base station may also be a relay node such as an IAB (Integrated Access and Backhaul) node. The base station may also be a DU (Distributed Unit) of the IAB node.

[0145] A program may be provided that causes a computer to execute each process performed by UE100 (NCR-UE100B, RIS-UE100C) or gNB200. The program may be recorded on a computer-readable medium. Using the computer-readable medium, the program can be installed 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. Furthermore, circuits that execute each process performed by UE100 or gNB200 may be integrated, and at least a part of UE100 or gNB200 may be configured as a semiconductor integrated circuit (chip set, SoC: System on a chip).

[0146] As used in this disclosure, the terms "based on" and "depending on" do not mean "based only on" or "depending only on," unless expressly stated otherwise. The term "based on" means both "based only on" and "based at least in part on." Similarly, the term "depending on" means both "depending only on" and "depending at least in part on." Furthermore, the terms "include," "comprise," and variations thereof do not mean including only the listed items, but may mean including only the listed items or may include additional items in addition to the listed items. Furthermore, the term "or," as used in this disclosure, is not intended to mean an exclusive or. Furthermore, any reference to elements using designations such as "first," "second," etc., as used in this disclosure does not generally limit the quantity or order of those elements. These designations may be used herein as a convenient method of distinguishing between two or more elements. Thus, a reference to a first and a second element does not imply that only two elements may be employed therein or that the first element must precede the second element in some way. In this disclosure, where articles are added by translation, such as a, an, and the in English, these articles shall include the plural unless the context clearly indicates otherwise.

[0147] The above describes the embodiments in detail with reference to the drawings, but the specific configuration is not limited to that described above, and various design changes can be made within the scope that does not deviate from the gist of the invention.

[0148] This application claims priority from Japanese Patent Application No. 2022-030104 (filed February 28, 2022), the entire contents of which are incorporated herein by reference.

[0149] (Addendum) The following additional notes are about the features of the above-described embodiment.

[0150] (1) A communication control method for controlling a relay device that relays radio signals between a base station and a user device in a time division duplex system, comprising: performing a downlink relay operation of relaying a downlink signal from the base station to the user equipment; performing an uplink relay operation of relaying an uplink signal from the user equipment to the base station after or before the downlink relay operation; and performing operation switching between the downlink relay operation and the uplink relay operation at a predetermined timing within a time interval between a downlink time interval in which the downlink relay operation is performed and an uplink time interval in which the uplink relay operation is performed. Communication control method.

[0151] (2) The predetermined timing is different from both the start timing and the end timing of a time interval between the downlink time interval and the uplink time interval. The communication control method according to (1) above.

[0152] (3) The method further comprises managing a timing advance for adjusting a transmission timing of the uplink signal from the relay device to the base station; the operation switching is switching from the uplink relay operation to the downlink relay operation, The predetermined timing is a timing at which a time indicated by a value obtained by dividing the timing advance by n (n≧2) has elapsed from the end timing of the uplink time interval. The communication control method according to (1) or (2) above.

[0153] (4) The method further comprises managing a timing advance for adjusting a transmission timing of the uplink signal from the relay device to the base station; the operation switching is switching from the downlink relay operation to the uplink relay operation, The predetermined timing is a timing at which a time indicated by a value obtained by dividing the timing advance by n (n≧2) has elapsed from the end timing of the downlink time interval. A communication control method according to any one of (1) to (3) above.

[0154] (5) The value of n is 2 A communication control method according to any one of (1) to (4) above.

[0155] (6) the operation switching is switching from the downlink relay operation to the uplink relay operation, The predetermined timing is a timing at a midpoint in a time interval between the downlink time interval and the uplink time interval. A communication control method according to any one of (1) to (5) above.

[0156] (7) the operation switching is switching from the downlink relay operation to the uplink relay operation, The predetermined timing is a designated timing designated by the base station within a time interval between the downlink time interval and the uplink time interval. A communication control method according to any one of (1) to (6) above.

[0157] (8) further comprising a step of receiving, from the base station, designated timing information indicating a symbol number as the designated timing; The step of performing the operation switching includes the step of performing the operation switching at a symbol corresponding to the symbol number indicated by the specified timing information. A communication control method according to any one of (1) to (7) above.

[0158] (9) The method further includes receiving downlink control information (DCI) from the base station, the DCI instructing the base station to control execution of the operation switching; The step of switching the operation includes the step of switching the operation at a timing when the DCI is received. A communication control method according to any one of (1) to (8) above.

[0159] (10) The relay device is a repeater device that amplifies and forwards the received radio waves. A communication control method according to any one of (1) to (9) above.

[0160] (11) The relay device is a Reconfigurable Intelligent Surface (RIS) device that changes the propagation direction of incident radio waves by reflection or refraction. A communication control method according to any one of (1) to (10) above.

[0161] (12) A relay device that relays radio signals between a base station and a user device in a time division duplex system, A process of performing a downlink relay operation of relaying a downlink signal from the base station to the user equipment; performing an uplink relay operation of relaying an uplink signal from the user equipment to the base station after or before the downlink relay operation; and a control unit that executes a process of switching between the downlink relay operation and the uplink relay operation at a predetermined timing within a time interval between a downlink time interval in which the downlink relay operation is performed and an uplink time interval in which the uplink relay operation is performed. Control terminal. [Explanation of symbols]

[0162] 1: Mobile communication system 100:UE 100B: NCR-UE 100C:RIS-UE 110: Receiving unit 120: Transmitter 130: Control unit 140: Interface 200 :gNB 210: Transmission unit 220: Receiving unit 230: Control unit 240: Backhaul communication unit 500A:NCR device 500B :RIS device 510A: Wireless unit 510a: Antenna part 510b :RF circuit 510c: Directivity control section 520A: NCR control section 520B: RIS control unit

Claims

1. A communication control method for controlling a relay device that relays radio signals between a base station and a user device in a time division duplex system, comprising: performing a downlink relay operation of relaying a downlink signal from the base station to the user equipment; performing an uplink relay operation of relaying an uplink signal from the user equipment to the base station after or before the downlink relay operation; performing operation switching between the downlink relay operation and the uplink relay operation at a predetermined timing within a time interval between a downlink time interval in which the downlink relay operation is performed and an uplink time interval in which the uplink relay operation is performed; receiving downlink control information (DCI) from the base station instructing control execution of the operation switching; the operation switching is switching from the downlink relay operation to the uplink relay operation, The operation switching includes performing the operation switching at the timing of receiving the DCI. Communication control method.

2. The predetermined timing is different from both the start timing and the end timing of a time interval between the downlink time interval and the uplink time interval. The communication control method according to claim 1 .

3. The relay device is a repeater device that amplifies and forwards the received radio waves. The communication control method according to claim 1 .

4. The relay device is a RIS (Reconfigurable Intelligent Surface) device that changes the propagation direction of incident radio waves by reflection or refraction. The communication control method according to claim 1 .

5. A relay device that relays radio signals between a base station and a user device in a time division duplex system, A process of performing a downlink relay operation of relaying a downlink signal from the base station to the user equipment; performing an uplink relay operation of relaying an uplink signal from the user equipment to the base station after or before the downlink relay operation; a process of switching between the downlink relay operation and the uplink relay operation at a predetermined timing within a time interval between a downlink time interval in which the downlink relay operation is performed and an uplink time interval in which the uplink relay operation is performed; a control unit that executes a process of receiving downlink control information (DCI) from the base station that instructs the execution of control of the operation switching; the operation switching is switching from the downlink relay operation to the uplink relay operation, The operation switching includes performing the operation switching at the timing of receiving the DCI. Control terminal.

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