COMMUNICATION METHOD, RELAY DEVICE, SYSTEM, PROGRAM, AND CHIP SET

Abstract

This communication method used in a mobile communication system includes: a step in which a base station forms a plurality of beams from one cell by beam-sweeping; and a step in which if the base station subjects only some beams of the plurality of beams to access restriction, the base station broadcasts, using some of the beams, first information indicating that access is restricted on a beam-by-beam basis.

Description

[Technical field]

[0001] The present disclosure relates to a communication method for use in a mobile communication system. [Background technology]

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

[0003] Radio signals (radio waves) in high frequency bands such as the millimeter wave band or the terahertz wave band have a high degree of linearity, which causes a problem of reducing the coverage of base stations. To solve this problem, a repeater device that is a type of relay device that relays radio signals between base stations and user devices and can be controlled from a network has been attracting attention (for example, see Non-Patent Document 1). Such a repeater device can expand the coverage of a base station while suppressing the occurrence of interference, for example, by amplifying a radio signal received from a base station and transmitting it by 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 method according to a first aspect is a communication method used in a mobile communication system, comprising the steps of: a base station forming a plurality of beams in one cell by beam sweeping; and, when the base station subjects only a portion of the plurality of beams to access restriction, broadcasting first information indicating that access restriction is being performed on a beam-by-beam basis via the portion of the beams.

[0006] A communication method according to a second aspect is a communication method used in a mobile communication system, comprising the steps of: a first network node managing a first cell controlling a relay device that relays radio signals between the first network node and a user equipment in the first cell; and the first network node communicating control state information regarding the control state of the relay device with a second network node managing a second cell adjacent to the first cell. [Brief description of the drawings]

[0007] [Figure 1] 1 is a diagram showing a configuration of a mobile communication system according to an embodiment. [Diagram 2] A diagram showing the configuration of a protocol stack of a wireless interface of a user plane that handles data. [Diagram 3] FIG. 2 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. 2 is a diagram illustrating an example of an application scenario of the relay device (NCR device) according to the first embodiment. [Diagram 5] FIG. 2 is a diagram illustrating an example of an application scenario of the relay device (NCR device) according to the first embodiment. [Figure 6] FIG. 4 is a diagram illustrating an example of a control method for a relay device (NCR device) according to the first embodiment. [Figure 7] 1 is a diagram illustrating an example of the configuration of a protocol stack in a mobile communication system having a relay device (NCR device) according to a first embodiment. [Figure 8]2 is a diagram illustrating an example of the configuration of a relay device (NCR device) according to the first embodiment. FIG. [Figure 9] FIG. 1 is a diagram illustrating a configuration example of a base station (gNB) according to an embodiment. [Figure 10] A figure showing an example of downlink signaling from a base station (gNB) to a control terminal (NCR-MT) in the first embodiment. [Figure 11] FIG. 1 is a diagram showing an example of uplink signaling from a control terminal (NCR-MT) to a base station (gNB) according to the first embodiment. [Figure 12] FIG. 2 is a diagram showing an example of an overall operation sequence of the mobile communication system according to the first embodiment. [Figure 13] FIG. 2 is a diagram for explaining beam sweeping according to the first embodiment. [Figure 14] A figure for explaining beam-based access restriction according to an embodiment. [Figure 15] A figure showing an example of beam-based access regulation for an embodiment. [Figure 16] A diagram showing an example of the operation of a gNB regarding beam-based access regulation in an embodiment. [Figure 17] A diagram showing an example of UE operation regarding beam-based access restriction in an embodiment. [Figure 18] FIG. 2 is a diagram for explaining a first operation example of inter-cell coordinated operation according to the embodiment. [Figure 19] FIG. 2 is a diagram illustrating a first operation example of inter-cell cooperation according to the embodiment. [Figure 20] FIG. 11 is a diagram for explaining a second operation example of the inter-cell coordinated operation according to the embodiment. [Figure 21] FIG. 11 is a diagram illustrating a second operation example of inter-cell cooperation according to the embodiment. [Figure 22] FIG. 11 is a diagram for explaining a relay device according to a second embodiment. [Diagram 23] FIG. 11 is a diagram for explaining a relay device according to a second embodiment. [Figure 24]FIG. 11 is a diagram for explaining an operation according to another embodiment. [Diagram 25] FIG. 2 illustrates a model of a network controlled repeater. [Figure 26] This diagram shows the protocol stack focusing on the C-plane of NCR-MT. [Figure 27] FIG. 1 shows multi-beam NCR. [Figure 28] FIG. 1 illustrates options for management models for a multi-beam repeater. [Figure 29] A diagram showing the CA / DC configuration of NCR-MT. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[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 enable appropriate control of a relay device that performs relay transmission 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) First embodiment First, a description will be given of a first embodiment. A relay device according to the first embodiment is a repeater device that can be controlled from a network.

[0012] (1.1) Overview of mobile communication systems FIG. 1 is a diagram showing a configuration of a mobile communication system according to a first embodiment. The mobile communication system 1 complies with the 5th Generation System (5GS) standard of the 3rd Generation Partnership Project (3GPP) (registered trademark; the same applies below). In the following description, 5GS is taken as an example, but the mobile communication system may be at least partially applied to a Long Term Evolution (LTE) system. The mobile communication system may be at least partially applied to a sixth generation (6G) 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. The 5GC 20 may be simply referred to as the core network (CN) 20.

[0014] 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 is a mobile phone terminal (including a smartphone) and / or a tablet terminal, a notebook PC, a communication module (including a communication card or a chipset), a sensor or a device provided in a sensor, a vehicle or a device provided in a vehicle (Vehicle UE), or an aircraft or a device provided in an aircraft (Aerial UE).

[0015] 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 the UE 100 that has established a connection with its own cell. The gNB 200 has a radio resource management (RRM) function, a routing function for user data (hereinafter simply referred to as "data"), a measurement control function for mobility control and scheduling, and the like. The term "cell" is used to indicate the smallest unit of a wireless communication area. The term "cell" is also used to indicate a function or resource for performing wireless communication with the UE 100. One cell belongs to one carrier frequency (hereinafter simply referred to as "frequency").

[0016] The gNB 200 may be functionally divided into a central unit (CU) and a distributed unit (DU). The CU controls the DU. The CU is a unit including upper layers included in a protocol stack described later, such as an RRC layer, an SDAP layer, and a PDCP layer. The CU is connected to the core network via an NG interface, which is a backhaul interface. The CU is connected to adjacent base stations via an Xn interface, which is an interface between base stations. The DU forms a cell. The DU 202 is a unit including lower layers included in a protocol stack described later, such as an RLC layer, an MAC layer, and a PHY layer. The DU is connected to the CU via an F1 interface, which is a fronthaul interface.

[0017] In addition, gNBs can also be connected to the Evolved Packet Core (EPC), which is the core network of LTE. LTE base stations can also be connected to 5GC. LTE base stations and gNBs can also be connected via an inter-base station interface.

[0018] 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 Non-Access Stratum (NAS) signaling. The UPF controls data forwarding. The AMF and the UPF are connected to the gNB 200 via an NG interface, which is an interface between a base station and a core network.

[0019] FIG. 2 is a diagram showing the configuration of a protocol stack of a radio interface of a user plane that handles data.

[0020] 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.

[0021] The PHY layer performs coding / decoding, modulation / demodulation, antenna mapping / demapping, and resource mapping / demapping. Data and control information are transmitted between the PHY layer of the UE 100 and the PHY layer of the gNB 200 via a physical channel. The PHY layer of the UE 100 receives downlink control information (DCI) transmitted from the gNB 200 on a physical downlink control channel (PDCCH). Specifically, the UE 100 performs blind decoding of the PDCCH using a radio network temporary identifier (RNTI) and acquires the successfully decoded DCI as DCI addressed to the UE. The DCI transmitted from the gNB 200 has CRC parity bits scrambled by the RNTI added thereto.

[0022] The gNB 200 also transmits a synchronization signal block (SSB: Synchronization Signal / PBCH block). For example, the SSB is composed of four consecutive OFDM (Orthogonal Frequency Division Multiplex) symbols, and includes a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a physical broadcast channel (PBCH) / master information block (MIB), and a demodulation reference signal (DMRS) of the PBCH. The bandwidth of the SSB is, for example, 240 consecutive subcarriers, that is, a bandwidth of 20RB.

[0023] 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 a transport channel. The MAC layer of gNB200 includes a scheduler. The scheduler determines the uplink and downlink transport format (transport block size, modulation and coding scheme (MCS)) and the resource blocks to be assigned to UE100.

[0024] The RLC layer transmits data to the RLC layer on the receiving side by using the functions of the MAC layer and the PHY layer. Data and control information are transmitted between the RLC layer of the UE 100 and the RLC layer of the gNB 200 via a logical channel.

[0025] The PDCP layer performs header compression / decompression, encryption / decryption, etc.

[0026] The SDAP layer maps IP flows, which are units for QoS (Quality of Service) control by the core network, to radio bearers, which are units for QoS control by the AS (Access Stratum). Note that if the RAN is connected to the EPC, the SDAP is not necessary.

[0027] 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).

[0028] 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.

[0029] Between the RRC layer of the UE 100 and the RRC layer of the gNB 200, RRC signaling for various settings is transmitted. The RRC layer controls logical channels, transport channels, and physical channels in response to establishment, re-establishment, and release of radio bearers. When there is a connection (RRC connection) between the RRC of the UE 100 and the RRC of the gNB 200, the UE 100 is in an RRC connected state. When there is no connection (RRC connection) between the RRC of the UE 100 and the RRC of the gNB 200, the UE 100 is in an RRC idle state. When the connection between the RRC of the UE 100 and the RRC of the gNB 200 is suspended, the UE 100 is in an RRC inactive state.

[0030] The NAS layer, which is located above the RRC layer, performs session management, mobility management, and the like. NAS signaling is transmitted between the NAS layer of the UE 100 and the NAS layer of the AMF 300A. The UE 100 has an application layer and the like in addition to the radio interface protocol. The layer below the NAS layer is called the AS layer.

[0031] (1.2) Example of application scenario for relay device 4 and 5 are diagrams showing an example of an application scenario of the NCR device according to the first embodiment.

[0032] 5G / NR is capable of wideband transmission using higher frequency bands than 4G / LTE. Radio signals in high frequency bands such as the millimeter wave band or the terahertz wave band have high linearity, so that the reduction of the coverage of the gNB200 becomes an issue. In FIG. 4, the UE100 may be located outside the coverage area of ​​the gNB200, for example, outside the area where a radio signal can be received directly from the gNB200. There may be an obstruction between the gNB200 and the UE100, and the UE100 may not be able to communicate with the gNB200 within line of sight.

[0033] As shown in Fig. 4, a repeater device (500A) which is a type of relay device that relays radio signals between the gNB 200 and the UE 100 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.

[0034] For example, the NCR device 500A amplifies a radio signal (radio wave) 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 without demodulating or modulating it, and transmits the amplified radio signal by directional transmission. Here, the NCR device 500A may transmit a radio signal with a fixed directivity (beam). The NCR device 500A may transmit a radio signal by a variable (adaptive) directional beam. This makes it possible to efficiently expand the coverage of the gNB 200. In the first embodiment, it is mainly assumed that the NCR device 500A is applied to downlink communication from the gNB 200 to the UE 100, but the NCR device 500A can also be applied to uplink communication from the UE 100 to the gNB 200.

[0035] Also, as shown in FIG. 5, a new UE (hereinafter referred to as "NCR-MT (Mobile termination)") 520A, which is a type of control terminal for controlling the NCR device 500A, is introduced. That is, the NCR device 500A has an NCR-Fwd (Forward) 510A, which is a type of repeater that relays a radio signal transmitted between the gNB 200 and the UE 100, specifically, changes the propagation state of the radio signal without demodulating or modulating the radio signal, and an NCR-MT 520A that performs wireless communication with the gNB 200 to control the NCR-Fwd 510A. In this way, the NCR-MT 520A controls the NCR device 500A in cooperation with the gNB 200 by establishing a wireless connection with the gNB 200 and performing wireless communication with the gNB 200. This makes it possible to realize efficient coverage expansion using the NCR device 500A. The NCR-MT 520A controls the NCR device 500A according to the control from the gNB 200.

[0036] The NCR-MT520A may be configured separately from the NCR-Fwd510A. For example, the NCR-MT520A may be located near the NCR-Fwd510A and electrically connected to the NCR-Fwd510A. The NCR-MT520A may be connected to the NCR-Fwd510A by wire or wirelessly. Alternatively, the NCR-MT520A may be configured integrally with the NCR-Fwd510A. The NCR-MT520A and the NCR-Fwd510A may be fixedly installed, for example, at the coverage edge (cell edge) of the gNB200 or on a wall or window of a building. The NCR-MT520A and the NCR-Fwd510A may be installed, for example, in a vehicle or the like and may be movable. Also, one NCR-MT520A may control multiple NCR-Fwd510A.

[0037] In the example shown in FIG. 5, the NCR device 500A (NCR-Fwd 510A) dynamically or quasi-statically changes a beam to be transmitted or received. For example, the NCR-Fwd 510A forms a beam toward each of the UE 100a and the UE 100b. The NCR-Fwd 510A may also form a beam toward the gNB 200. For example, in a communication resource between the gNB 200 and the UE 100a, the NCR-Fwd 510A transmits a radio signal received from the gNB 200 toward the UE 100a by beamforming and / or transmits a radio signal received from the UE 100a toward the gNB 200 by beamforming. In the communication resources between the gNB 200 and the UE 100b, the NCR-Fwd 510A transmits a radio signal received from the gNB 200 toward the UE 100b by beamforming, and / or transmits a radio signal received from the UE 100b toward the gNB 200 by beamforming. Instead of or in addition to beamforming, the NCR-Fwd 510A may form a null (so-called null steering) toward a UE 100 (not shown) and / or an adjacent gNB 200 (not shown) that is not a communication partner, in order to suppress interference.

[0038] FIG. 6 is a diagram showing an example of a control method of the NCR device 500A according to the first embodiment. As shown in FIG. 6, the NCR-Fwd 510A relays radio signals (also referred to as "UE signals") between the gNB 200 and the UE 100. The UE signals include an uplink signal (also referred to as "UE-UL signal") transmitted from the UE 100 to the gNB 200 and a downlink signal (also referred to as "UE-DL signal") transmitted from the gNB 200 to the UE 100. The NCR-Fwd 510A relays the UE-UL signal from the UE 100 to the gNB 200, and relays the UE-DL signal from the gNB 200 to the UE 100. The radio link between the NCR-Fwd 510A and the UE 100 is also referred to as an "access link". The radio link between the NCR-Fwd 510A and the gNB 200 is also referred to as a "backhaul link".

[0039] The NCR-MT520A transmits and receives wireless signals (herein referred to as "NCR-MT signals") to and from the gNB200. The NCR-MT signals include uplink signals (herein referred to as "NCR-MT-UL signals") transmitted from the NCR-MT520A to the gNB200, and downlink signals (herein referred to as "NCR-MT-DL signals") transmitted from the gNB200 to the NCR-MT520A. The NCR-MT-UL signals include signaling for controlling the NCR device 500A. The wireless link between the NCR-MT520A and the gNB200 is also referred to as a "control link."

[0040] The gNB200 directs a beam to the NCR-MT520A based on the NCR-MT-UL signal from the NCR-MT520A. Since the NCR device 500A is installed (co-located) in the same place as the NCR-MT520A, when the backhaul link and the control link have the same frequency, when the gNB200 directs a beam to the NCR-MT520A, the beam is also directed to the NCR-Fwd510A as a result. The gNB200 transmits the NCR-MT-DL signal and the UE-DL signal using the beam. The NCR-MT520A receives the NCR-MT-DL signal. Note that when the NCR-Fwd510A and the NCR-MT520A are at least partially integrated, the functions (e.g., antennas) of transmitting, receiving, or relaying the UE signal and / or the NCR-MT signal may be integrated in the NCR-Fwd510A and the NCR-MT520A. The beam includes a transmission beam and / or a reception beam. A beam is a general term for transmission and / or reception controlled to maximize the power of a transmission wave and / or a reception wave in a specific direction by adjusting / adapting antenna weights, etc.

[0041] 7 is a diagram showing an example of the configuration of a protocol stack in a mobile communication system 1 having an NCR device 500A according to the first embodiment. The NCR-Fwd 510A relays wireless signals transmitted and received between the gNB 200 and the UE 100. The NCR-Fwd 510A has an RF (Radio Frequency) function for amplifying and relaying a received wireless signal, and performs directional transmission by beamforming (for example, analog beamforming).

[0042] The NCR-MT520A 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-MT520A exchanges downlink signaling and / or uplink signaling (described below) with the gNB200 through at least one of PHY, MAC, RRC, and F1-AP. If the NCR-MT520A is a type or part of a base station, the NCR-MT520A may exchange with the gNB200 through an Xn AP (Xn-AP), which is an interface between base stations.

[0043] (1.3) Example of relay device configuration 8 is a diagram showing an example of the configuration of an NCR device 500A which is a relay device according to the first embodiment. The NCR device 500A includes an NCR-Fwd 510A, an NCR-MT 520A, and an interface 530.

[0044] The NCR-Fwd510A has a radio unit 511A and an NCR control unit 512A. The radio unit 511A has an antenna unit 511a including a plurality of antennas (a plurality of antenna elements), an RF circuit 511b including an amplifier, and a directivity control unit 511c that controls the directivity of the antenna unit 511a. The RF circuit 511b amplifies and relays (transmits) radio signals transmitted and received by the antenna unit 511a. The RF circuit 511b may convert an analog radio signal into a digital signal and reconvert it into an analog signal after digital signal processing. The directivity control unit 511c may perform analog beamforming by analog signal processing. The directivity control unit 511c may perform digital beamforming by digital signal processing. The directivity control unit 511c may perform hybrid analog and digital beamforming. The NCR control unit 512A controls the radio unit 511A in response to a control signal from the NCR-MT520A. The NCR control unit 512A may include at least one processor. The NCR control unit 512A may output information regarding the capabilities of the NCR device 500A to the NCR-MT 520A.

[0045] The NCR-MT520A has a receiving unit 521, a transmitting unit 522, and a control unit 523. The receiving unit 521 performs various receptions under the control of the control unit 523. The receiving unit 521 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 the signal to the control unit 523. The transmitting unit 522 performs various transmissions under the control of the control unit 523. The transmitting unit 522 includes an antenna and a transmitter. The transmitter converts a baseband signal (transmitted signal) output by the control unit 523 into a radio signal and transmits the signal from the antenna. The control unit 523 performs various controls in the NCR-MT520A. The control unit 523 includes at least one processor and at least one memory. The memory stores a program 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 523 executes the functions of at least one of the layers PHY, MAC, RRC, and F1-AP.

[0046] The interface 530 electrically connects the NCR-Fwd 510A and the NCR-MT 520A. The control unit 523 of the NCR-MT 520A controls the NCR-Fwd 510A via the interface 530.

[0047] In the first embodiment, the receiver 521 of the NCR-MT 520A receives signaling (downlink signaling) used to control the NCR device 500A from the gNB 200 via wireless communication. The controller 523 of the NCR-MT 520A controls the NCR device 500A based on the signaling. This enables the gNB 200 to control the NCR-Fwd 510A via the NCR-MT 520A.

[0048] In the first embodiment, the control unit 523 of the NCR-MT 520A may transmit NCR capability information indicating the capability of the NCR device 500A to the gNB 200 by wireless communication. The NCR capability information is an example of uplink signaling from the NCR-MT 520A to the gNB 200. This allows the gNB 200 to grasp the capability of the NCR device 500A.

[0049] (1.4) Example of base station configuration 9 is a diagram showing an example of the configuration of the gNB 200 according to the first embodiment. The gNB 200 includes a transmitter 210, a receiver 220, a controller 230, and a backhaul communication unit 240.

[0050] 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.

[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 in 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. The CPU executes programs stored in the memory to perform various processing.

[0052] The backhaul communication unit 240 is connected to adjacent 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., the functions are divided), and both units may be connected to each other via an F1 interface.

[0053] In the first embodiment, the transmitter 210 of the gNB 200 transmits signaling (downlink signaling) used to control the NCR-Fwd 510A to the NCR-MT 520A by wireless communication. This enables the gNB 200 to control the NCR device 500A via the NCR-MT 520A. In the first embodiment, the receiver 220 of the gNB 200 may receive NCR capability information indicating the capability of the NCR device 500A from the NCR-MT 520A by wireless communication.

[0054] (1.5) An example of downlink signaling FIG. 10 is a diagram showing an example of downlink signaling from gNB200 to NCR-MT520A according to the first embodiment.

[0055] The gNB200 (transmitter 210) transmits downlink signaling to the NCR-MT520A. 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-specific signaling. The downlink signaling may be broadcast signaling. The downlink signaling may be a fronthaul message (e.g., an F1-AP message). If the NCR-MT520A is a type or part of a base station, the NCR-MT520A may communicate with the gNB200 via an Xn AP (Xn-AP), which is an interface between base stations.

[0056] For example, the gNB 200 (transmitter 210) transmits an NCR control signal that specifies the operation state of the NCR device 500A as downlink signaling to the NCR-MT 520A that has established a wireless connection with the gNB 200 (step S1A). The NCR control signal that specifies the operation state of the NCR device 500A may be 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 for each UE, and transmitted to the NCR-MT 520A. 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 that is encapsulated in a message of a layer lower than the RRC layer and transmitted. In addition, the NCR-MT 520A (transmitter 522) may transmit, in the uplink, a response message to the downlink signaling from the gNB 200. The response message may be transmitted in response to the NCR device 500A completing the setting specified in the downlink signaling or receiving the setting.

[0057] The NCR control signal may include frequency control information that specifies the center frequency of a wireless signal (e.g., a component carrier) that the NCR-Fwd510A is to relay. When the NCR control signal received from the gNB200 includes frequency control information, the NCR-MT520A (control unit 523) controls the NCR-Fwd510A to relay a wireless signal having a center frequency indicated by the frequency control information (step S2A). 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 gNB200 can specify, via the NCR-MT520A, the center frequency of a wireless signal that the NCR-Fwd510A is to relay.

[0058] The NCR control signal may include mode control information that specifies an operation mode of the NCR-Fwd510A. 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-Fwd510A performs non-directional transmission and / or reception, a mode in which the NCR-Fwd510A performs fixed directional transmission and / or reception, a mode in which the NCR-Fwd510A performs transmission and / or reception using a variable directional beam, and a mode in which the NCR-Fwd510A performs MIMO (Multiple Input Multiple Output) relay transmission. The operation mode may be any of a beamforming mode (i.e., a mode that emphasizes improvement of a desired wave) and a null steering mode (i.e., a mode that emphasizes suppression of an interference wave). When the NCR control signal received from the gNB 200 includes mode control information, the NCR-MT 520A (control unit 523) controls the NCR-Fwd 510A to operate in the operation mode indicated by the mode control information (step S2A). When the NCR control signal includes the mode control information, the gNB 200 can specify the operation mode of the NCR-Fwd 510A via the NCR-MT 520A.

[0059] Here, the mode in which the NCR device 500A performs non-directional transmission and / or reception is a mode in which the NCR-Fwd510A performs relay in all directions, and may be referred to as an omni mode. The mode in which the NCR-Fwd510A performs fixed directional transmission and / or reception may be a directional mode realized by one directional antenna. The mode may 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 gNB200 to the NCR-MT520A. The mode in which the NCR-Fwd510A performs transmission and / or reception using a variable directional beam may be a mode in which analog beamforming is performed. The mode may be a mode in which digital beamforming is performed. The mode may be a mode in which hybrid beamforming is performed. The mode may be a mode in which an adaptive beam unique to the UE100 is formed. Any of these modes may be specified (set) by the gNB200 to the NCR-MT520A. In addition, in the operation mode in which beamforming is performed, beam control information described below may be provided from the gNB 200 to the NCR-MT 520A. 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 may be a mode in which MU (Multi-User) spatial multiplexing is performed. The mode may be a mode in which transmit diversity is performed. Any of these modes may be specified (set) by the gNB 200 to the NCR-MT 520A. The operation mode may include a mode in which relay transmission by the NCR-Fwd 510A is turned on (activated) and a mode in which relay transmission by the NCR-Fwd 510A is turned off (deactivated). Any of these modes may be specified (set) by the gNB 200 to the NCR-MT 520A by an NCR control signal.

[0060] The NCR control signal may include beam control information that specifies a transmission direction, a transmission weight, or a beam pattern when the NCR-Fwd510A 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). The beam control information may include angle information for beam formation. When the NCR control signal received from the gNB200 includes beam control information, the NCR-MT520A (control unit 523) controls the NCR-Fwd510A to form a transmission directivity (beam) indicated by the beam control information (step S2A). By including the beam control information in the NCR control signal, the gNB200 can control the transmission directivity of the NCR device 500A via the NCR-MT520A.

[0061] The NCR control signal may include output control information that specifies the degree to which the NCR-Fwd510A amplifies the radio signal (amplification gain) or transmission power. The output control information may be information indicating a difference value (i.e., a relative value) between the current amplification gain or transmission power and a target amplification gain or transmission power. When the NCR control signal received from the gNB200 includes the output control information, the NCR-MT520A (control unit 523) controls the NCR-Fwd510A so as to change the amplification gain or transmission power to the one indicated by the output control information (step S2A). 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-Fwd510A. The output control information may be information that specifies the transmission power of the NCR-Fwd510A.

[0062] When one NCR-MT520A controls multiple NCR-Fwd510A, the gNB200 (transmitter 210) may transmit an NCR control signal to the NCR-MT520A for each NCR-Fwd510A. In this case, the NCR control signal may include an identifier (NCR identifier) ​​of the corresponding NCR-Fwd510A. The NCR-MT520A (controller 523) that controls multiple NCR-Fwd510A determines the NCR-Fwd510A 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 the NCR identifier may be transmitted from the NCR-MT520A to the gNB200 together with the NCR control signal even when the NCR-MT520A controls only one NCR-Fwd510A.

[0063] In this way, the NCR-MT 520A (control unit 523) controls the NCR-Fwd 510A based on the NCR control signal from the gNB 200. This enables the gNB 200 to control the NCR-Fwd 510A via the NCR-MT 520A.

[0064] (1.6) An example of uplink signaling FIG. 11 is a diagram showing an example of uplink signaling from the NCR-MT 520A to the gNB 200 according to the first embodiment.

[0065] The NCR-MT520A (transmitter 210) transmits uplink signaling to the gNB200. The uplink signaling may be an RRC message, which is signaling of the RRC layer. The uplink signaling may be MAC CE, which is signaling of the MAC layer. 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). 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. That is, the uplink signaling stores a higher layer message in a container of a lower layer. In addition, gNB200 (transmitter 210) may transmit a response message in response to the uplink signaling from NCR-MT520A on the downlink, and NCR-MT520A (receiver 521) may receive the response message.

[0066] For example, the NCR-MT 520A (transmitter 522) that has established a wireless connection with the gNB 200 transmits NCR capability information indicating the capability of the NCR device 500A to the gNB 200 as uplink signaling (step S5A). The NCR-MT 520A (transmitter 522) 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-MT 520A (transmitter 522) 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.

[0067] The NCR capability information may include supported frequency information indicating frequencies supported by the NCR-Fwd510A. The supported frequency information may be a numerical value or an index indicating a center frequency of frequencies supported by the NCR-Fwd510A. The supported frequency information may be a numerical value or an index indicating a range of frequencies supported by the NCR-Fwd510A. When the NCR capability information received from the NCR-MT520A includes the supported frequency information, the gNB200 (control unit 230) can ascertain the frequencies supported by the NCR-Fwd510A based on the supported frequency information. Then, the gNB200 (control unit 230) may set the center frequency of the wireless signal targeted by the NCR device 500A within the range of frequencies supported by the NCR-Fwd510A.

[0068] The NCR capability information may include mode capability information related to operation modes that the NCR-Fwd510A 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-Fwd510A performs non-directional transmission and / or reception, a mode in which the NCR-Fwd510A performs fixed directional transmission and / or reception, a mode in which the NCR-Fwd510A performs transmission and / or reception using a variable directional beam, and a mode in which the NCR-Fwd510A performs MIMO (Multiple Input Multiple Output) relay transmission. The operation mode may be either a beamforming mode (i.e., a mode that emphasizes improvement of a desired wave) or a null steering mode (i.e., a mode that emphasizes suppression of an interference wave). The mode capability information may be information indicating which of these operation modes the NCR-Fwd510A can support. The mode capability information may be information indicating which of these operation modes the NCR-Fwd510A can switch between. When the NCR capability information received from the NCR-MT 520A includes mode capability information, the gNB 200 (control unit 230) can determine the operation mode and mode switching supported by the NCR-Fwd 510A based on the mode capability information. The gNB 200 (control unit 230) may then set the operation mode of the NCR-Fwd 510A within the range of the determined operation modes and mode switching.

[0069] The NCR capability information may include beam capability information indicating a beam variable range, a beam variable resolution, or the number of variable patterns when the NCR-Fwd510A transmits and / or receives using a variable directional beam. The beam capability information may be, for example, information indicating a variable range of a beam angle based on the horizontal or vertical direction (for example, controllable from 30° to 90°). The beam capability information may be information indicating an absolute angle. The beam capability information may be expressed by a direction and / or an elevation angle to which the beam is directed. The beam capability information may be information indicating an angle change for each variable step (for example, 5° / step horizontally, 10° / step vertically). The beam capability information may be information indicating the number of variable steps (for example, 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-Fwd510A (for example, a total of 10 patterns including beam patterns 1 to 10). When the NCR capability information received from the NCR-MT520A includes beam capability information, the gNB200 (control unit 230) can grasp the beam angle change or beam pattern that the NCR-Fwd510A can support based on the beam capability information. Then, the gNB200 (control unit 230) may set the beam of the NCR-Fwd510A within the range of the grasped beam angle change or beam pattern. The beam capability information may be null capability information. In the case of null capability information, the beam capability information indicates the null control capability when null steering is performed.

[0070] 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 the NCR control signal or the timing when the UE 100 transmits a setting completion for the NCR control signal to the gNB 200 until the control (change of the operation mode and / or change of the beam) according to the NCR control signal is completed. When the NCR capability information received from the NCR-MT 520A includes the control delay information, the gNB 200 (control unit 230) can grasp the control delay time in the NCR-Fwd 510A based on the control delay information.

[0071] The NCR capability information may include amplification characteristic information related to the amplification characteristic or output power characteristic of the radio signal in the NCR-Fwd510A. The amplification characteristic information may be information indicating the amplifier gain (dB), beamforming gain (dB), or antenna gain (dBi) of the NCR-Fwd510A. The amplification characteristic information may be information indicating the amplification variable range (e.g., 0 dB to 60 dB) in the NCR-Fwd510A. The amplification characteristic information may be information indicating the number of steps (e.g., 10 steps) of the amplification degree that the NCR-Fwd510A can change, or the amplification degree for each 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-Fwd510A. The amplification characteristic information may be information indicating the number of steps (eg, 10 steps) of the output power that can be changed by the NCR-Fwd510A, or the output power for each variable step (eg, 10 dBm / step or 10 dB / step).

[0072] 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 based on 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 a place where the antenna unit 511a of the NCR-Fwd 510A is installed.

[0073] The NCR capability information may include antenna information indicating the number of antennas possessed by the NCR-Fwd510A. The antenna information may be information indicating the number of antenna ports possessed by the NCR-Fwd510A. 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)-1". For example, in the case of two antennas, the degree of freedom is 1. In the case of two antennas, a beam pattern resembling a figure of eight is formed, but the degree of freedom is 1 because directivity control is possible in only one direction.

[0074] When the NCR-MT520A controls a plurality of NCR-Fwd510A, the NCR-MT520A (transmitter 522) may transmit NCR capability information for each NCR-Fwd510A to the gNB200. In this case, the NCR capability information may include the number of NCR-Fwd510A and / or the identifier (NCR identifier) ​​of the corresponding NCR-Fwd510A. Furthermore, when the NCR-MT520A controls a plurality of NCR-Fwd510A, the NCR-MT520A (transmitter 522) may transmit information indicating at least one of the identifiers of the plurality of NCR-Fwd510A and the number of the plurality of NCR-Fwd510A. Note that the NCR identifier may be transmitted from the NCR-MT520A to the gNB200 together with the NCR capability information even when the NCR-MT520A controls only one NCR-Fwd510A.

[0075] (1.7) Example of overall operation sequence Fig. 12 is a diagram showing an example of an overall operation sequence of the mobile communication system 1 according to the first embodiment. In the sequence diagram referred to in the following embodiment, non-essential steps are indicated by dashed lines. Note that, as will be described in detail later, "NCR" in Fig. 12 may be read as "RIS".

[0076] In step S11, the gNB 200 (transmitter 210) broadcasts NCR support information indicating that the gNB 200 supports the NCR-MT520A. For example, the gNB 200 (transmitter 210) broadcasts a system information block (SIB) including the NCR support information. The NCR support information may be information indicating that the NCR-MT520A is accessible. Alternatively, the gNB 200 (transmitter 210) may broadcast NCR non-support information indicating that the gNB 200 does not support the NCR-MT520A. The NCR non-support information may be information indicating that the NCR-MT520A is not accessible.

[0077] At this stage, the NCR-MT520A may be in an RRC idle state or an RRC inactive state. The NCR-MT520A (control unit 523) that has not established a wireless connection with the gNB200 may determine that access to the gNB200 is permitted in response to receiving NCR support information from the gNB200, and may perform an access operation to establish a wireless connection with the gNB200. The NCR-MT520A (control unit 523) may perform cell reselection by regarding the gNB200 (cell) to which access is permitted as the highest priority.

[0078] On the other hand, if the gNB 200 does not broadcast NCR support information (or broadcasts NCR non-support information), the NCR-MT 520A (control unit 523) that has not established a wireless connection with the gNB 200 may determine that it is not possible to access (establish a connection with) the gNB 200. This allows the NCR-MT 520A to establish a wireless connection only with gNBs 200 that can handle the NCR-MT 520A.

[0079] In addition, when the gNB 200 is congested, the gNB 200 may broadcast access restriction information that restricts access from the UE 100. However, the NCR-MT 520A can be regarded as an entity on the network side, unlike the normal UE 100. Therefore, the NCR-MT 520A may ignore the access restriction information from the gNB 200. For example, when the NCR-MT 520A (control unit 523) 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 broadcasts the access restriction information. For example, the NCR-MT 520A (control unit 523) may not execute (or may ignore) UAC (Unified Access Control). Alternatively, a special value indicating that the access is an NCR-MT access may be used as either or both of AC / AI (Access Category / Access Identity) used in UAC.

[0080] In step S12, the NCR-MT 520A (control unit 523) starts a random access procedure for the gNB 200. In the random access procedure, the NCR-MT 520A (transmission unit 522) transmits a random access preamble (Msg1) and an RRC message (Msg3) to the gNB 200. Also, in the random access procedure, the NCR-MT 520A (reception unit 521) receives a random access response (Msg2) and an RRC message (Msg4) from the gNB 200.

[0081] In step S13, when establishing a wireless connection with the gNB 200, the NCR-MT 520A (transmitter 522) may transmit NCR-MT information indicating that its own UE is an NCR-MT to the gNB 200. For example, during a random access procedure with the gNB 200, the NCR-MT 520A (transmitter 522) transmits to the gNB 200 the NCR-MT information included in a message for the random access procedure (e.g., Msg1, Msg3, Msg5). The gNB 200 (controller 230) recognizes that the accessed UE 100 is the NCR-MT 520A based on the NCR-MT information received from the NCR-MT 520A, and can, for example, remove the NCR-MT 520A from the access restriction target (i.e., accept the access). When the random access procedure is completed, the NCR-MT 520A transitions from the RRC idle state or the RRC inactive state to the RRC connected state.

[0082] In step S14, the gNB 200 (transmitter 522) transmits a capability inquiry message to the NCR-MT 520A to inquire about the capability of the NCR-MT 520A. The NCR-MT 520A (receiver 521) receives the capability inquiry message.

[0083] In step S15, the NCR-MT 520A (transmitter 522) transmits a capability information message including NCR capability information to the gNB 200. The capability information message may be an RRC message, for example, a UE Capability message. 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.

[0084] In step S16, the gNB 200 (transmitter 522) transmits a configuration message including various settings related to the NCR device 500A to the NCR-MT 520A. The NCR-MT 520A (receiver 521) receives the configuration message. The configuration message is a type of the above-mentioned downlink signaling. The configuration message may be an RRC message, for example, an RRC Reconfiguration message.

[0085] In step S17, the gNB 200 (transmitter 522) transmits a control instruction to the NCR-MT 520A, which specifies the operation state of the NCR-Fwd 510A. The control instruction may be the above-mentioned NCR control signal (e.g., L1 / L2 signaling). The NCR-MT 520A (receiver 521) receives the control instruction. The NCR-MT 520A (controller 523) controls the NCR-Fwd 510A in response to the control instruction.

[0086] In step S18, the NCR-MT 520A controls the NCR device 500A according to the above settings (and control instructions). Note that the NCR-MT 520A may autonomously control the NCR device 500A without depending on control instructions from the gNB 200. For example, the NCR-MT 520A may autonomously control the NCR device 500A based on the location of the UE 100 and / or information that the NCR-MT 520A receives from the UE 100.

[0087] (1.8) Beam Sweeping FIG. 13 is a diagram for explaining beam sweeping according to the embodiment.

[0088] The gNB 200 performs beam sweeping, which sequentially switches and transmits beams in different directions. At this time, the gNB 200 transmits a different SSB for each beam. The SSB is periodically transmitted from the gNB 200 to the cell as an SSB burst consisting of multiple SSBs. The multiple SSBs in one SSB burst are each assigned an SSB index, which is an identifier. The SSBs are beamformed and transmitted in different directions. The NCR device 500A (NCR-MT520A) reports to the gNB 200 during a random access channel (RACH) procedure which direction the beam had good reception quality. Specifically, the NCR device 500A (NCR-MT520A) transmits a random access preamble to the gNB 200 in a random access channel (RACH) occasion associated with the SSB index in which the beam had good reception quality. As a result, the gNB 200 can identify the optimal beam for the NCR device 500A (NCR-MT520A).

[0089] In addition, such an SSB may be transmitted in an initial BWP (initial DL BWP). When the NCR device 500A (NCR-MT520A) is in an RRC connected state, a dedicated BWP may be set and activated in the NCR device 500A (NCR-MT520A). In the dedicated BWP, a channel state information reference signal (CSI-RS) may be used as a reference signal instead of an SSB. In the following, an example in which beam information identifying a beam is an SSB index will be mainly described, assuming that a beam and an SSB (specifically, an SSB index) have a one-to-one relationship. However, the beam may be associated with a CSI-RS. The beam information identifying a beam may be a CSI-RS index.

[0090] (1.9) Beam-based access restrictions FIG. 14 is a diagram for explaining the beam-based access restriction according to the embodiment.

[0091] By installing the NCR device 500A in a cell, it is possible to extend the coverage of the cell by the NCR device 500A. Therefore, the number of UEs 100 accommodated in the cell also increases, the cell becomes congested, and the resources of the cell may become tight.

[0092] In the example of FIG. 14, the NCR device 500A (NCR-Fwd 510A) is relaying the beam #1 formed by the gNB 200. The beam #1 is associated with SSB #1 (where "#1" represents the SSB index). The UEs 100a and 100b are receiving the beam #1 formed by the NCR device 500A (NCR-Fwd 510A). The UE 100c is receiving the beam #2 associated with SSB #2. The UE 100c is receiving the beam #3 associated with SSB #3.

[0093] Here, access restriction is specified as a mechanism for restricting access to the cell of the gNB 200 when the load of the gNB 200 increases. In general access restriction, the gNB 200 sets a parameter (cellBarred) in a master information block (MIB) broadcast by its own cell to a value indicating access prohibition (barred). When a UE 100 in an RRC idle state or an RRC inactive state finds a cell broadcasting such an MIB, it determines that access to the cell (random access) is prohibited, and searches for other cells. Such general access restriction has a problem in that access of all UEs 100 is restricted.

[0094] In the example of Fig. 14, the gNB 200 controls the NCR device 500A to be turned off, which can reduce the load on the gNB 200. However, the UEs 100a and 100b that are already connected need to perform beam recovery, etc., and there is a problem that communication cannot be performed if no other suitable beam can be found. Therefore, in the embodiment, it is possible to perform access restriction on a beam-by-beam basis. This makes it possible to perform fine-grained access restriction.

[0095] FIG. 15 is a diagram illustrating an example of beam-based access restriction according to the embodiment.

[0096] In the embodiment, the gNB 200 forms multiple beams in one cell by beam sweeping. When only some of the multiple beams are subject to access restriction, the gNB 200 broadcasts first information indicating that access restriction is performed on a beam-by-beam basis on the some of the beams. This makes it possible to perform access restriction on a beam-by-beam basis rather than on a cell-by-cell basis.

[0097] The first information is information that is specified separately from the second information (cellBarred) that indicates the presence or absence of access restriction on a cell-by-cell basis. For example, the first information is 1-bit information that is set to a first value (e.g., "1") when access restriction on a beam-by-beam basis is performed, and is set to a second value (e.g., "0") when access restriction on a beam-by-beam basis is not performed. The first information is also referred to as "beamBarred", the first value is also referred to as "barred", and the second value is also referred to as "notBarred".

[0098] For example, the gNB 200 transmits an MIB including information indicating the first information (beamBarred). Since the MIB is included in the SSB, the UE 100 that receives the beam (SSB) can grasp whether the beam is accessible based on the first information (beamBarred) in the MIB included in the beam (SSB).

[0099] The gNB 200 may transmit a MIB including first information (beamBarred) in which barred is set in the beam for which access is restricted, and second information indicating that access is not restricted on a cell-by-cell basis. In this way, the UE 100 that receives the MIB in the beam of the cell can understand that access to the beam is restricted, although access to the cell is not restricted, and can search for other beams of the cell.

[0100] The second information (cellBarred) is general access restriction information. The second information is 1-bit information to which a first value (e.g., "1") is set when access restriction is performed on a cell-by-cell basis, and a second value (e.g., "0") is set when access restriction is not performed on a cell-by-cell basis. The second information is also referred to as "cellBarred", the first value is also referred to as "barred", and the second value is also referred to as "notBarred".

[0101] When the gNB 200 targets the entire cell for access restriction, the gNB 200 may broadcast the second information indicating that the access restriction is performed on a cell-by-cell basis using multiple beams. For example, the gNB 200 may transmit the MIB including the cellBarred in which the barred is set, using all beams of the gNB 200's cell.

[0102] The NCR device 500A, which relays the beam to which access is restricted, transfers the first information (beamBarred) from the gNB 200. As a result, the UE 100 receiving the beam formed by the NCR device 500A can grasp whether the beam is accessible or not based on the first information (beamBarred) received from the NCR device 500A.

[0103] In addition, the NCR device 500A (NCR-MT520A) may be allowed to access the gNB 200 regardless of cellBarred and beamBarred. That is, the NCR device 500A (NCR-MT520A) may be able to ignore cellBarred and beamBarred. For example, even if the NCR device 500A (NCR-MT520A) receives cellBarred with barred set or beamBarred with barred set from the gNB 200, the NCR device 500A (NCR-MT520A) may be allowed to access the gNB 200.

[0104] Alternatively, the NCR device 500A (NCR-MT520A) may ignore the cellBarred, but may apply the beamBarred. For example, when the NCR device 500A (NCR-MT520A) receives a beamBarred with the barred set from the gNB 200, the NCR device 500A (NCR-MT520A) may be prohibited from accessing the gNB 200.

[0105] Figure 16 is a diagram showing an example of the operation of gNB200 regarding beam-based access regulation.

[0106] In step S101, the gNB 200, which forms multiple beams in its own cell, determines whether to perform access restriction on a cell-by-cell basis. If it is determined that access restriction on a cell-by-cell basis is to be performed (step S101: YES), in step S102, the gNB 200 transmits the MIB including the cellBarred in which the barred is set, in all beams of its own cell.

[0107] When it is determined that the access restriction is not performed on a cell basis (step S101: NO), in step S103, the gNB 200 determines whether or not to perform access restriction on a beam basis, that is, access restriction on a specific beam among the multiple beams of the own cell. When it is determined that the access restriction is performed on a beam basis (step S103: YES), in step S104, the gNB 200 transmits the MIB including the beamBarred in which the barred is set, only on the specific beam.

[0108] 17 is a diagram showing an example of an operation of the UE 100 regarding beam-based access restriction. Here, the UE 100 may be in an RRC idle state or an RRC inactive state.

[0109] In step S201, UE 100, which receives MIB transmitted by a cell beam, judges whether or not it has received MIB including cellBarred with barred set. If it is judged that MIB including cellBarred with barred set has been received (step S201: YES), in step S202, UE 100 judges that access to the cell is prohibited, and performs cell reselection processing to another cell.

[0110] On the other hand, when it is determined that the MIB including the cellBarred in which notBarred is set has been received (step S201: NO), in step S203, UE100 determines whether or not the MIB including the beamBarred in which barred is set has been received. When it is determined that the MIB including the beamBarred in which barred is set has been received (step S203: YES), in step S204, UE100 determines that access to the beam is prohibited, and performs a process of searching for other beams of the cell. That is, UE100 refrains from accessing via an SSB including a MIB indicating the access prohibition. Here, UE100 may exclude the beam (SSB) from candidates and search for another beam (SSB). UE100 may be prohibited from accessing only for a certain period of time after receiving the MIB. The certain period may be broadcast by the gNB200 via an SIB or the like. The certain period may be determined in advance by a system specification. In this case, after the certain period has elapsed, UE 100 may receive the beam (SSB) again and determine whether access is possible.

[0111] If it is determined that a MIB including beamBarred with notBarred set has been received (step S203: NO), in step S205, UE100 determines that access to gNB200 via the beam (SSB) is possible.

[0112] Although an example of adding beamBarred to the MIB has been described above, beamBarred may be added to, for example, SIB type 1 (SIB1). For example, the gNB 200 may set "beamBarred=barred" for SIB1 transmitted with a beam in the direction of the NCR device 500A, and set "beamBarred=notBarred" for SIB1 transmitted with a beam in other directions.

[0113] (1.10) Inter-cell cooperative operation Assuming that the NCR device 500A is installed at a cell edge, the NCR device 500A may be an interference source to an adjacent cell. In the embodiment, a first network node that manages a first cell controls an NCR device 500A (relay device) that relays a radio signal between the first network node and the UE 100 in the first cell. The first network node communicates control state information regarding the control state of the NCR device 500A with a second network node that manages a second cell adjacent to the first cell. This enables cooperation between cells, and can suppress the occurrence of interference caused by the NCR device 500A.

[0114] The first network node may be a first DU connected to a CU. The second network node may be a second DU connected to the CU. The first DU may communicate control state information with the second DU via the CU.

[0115] Alternatively, the first network node may be a first gNB. The second network node may be a second gNB connected to the first gNB via an inter-base station interface (Xn interface). The first gNB may communicate control state information with the second DU via the Xn interface.

[0116] The first network node may notify the second network node of control state information indicating a control state of the NCR device 500A under the control of the first network node. Prior to the notification, the second network node may make an inquiry to the first network node to request notification of the control state information.

[0117] The second network node may notify the first network node of control state information indicating the control state of the NCR device 500A desired by the second network node.

[0118] (1.10.1) First example of inter-cell cooperation 18 is a diagram for explaining a first operation example of the inter-cell cooperation operation according to the embodiment. In the first operation example, the first network node is the DU 250a (first DU), and the second network node is the DU 250b (second DU). The DU 250a (first DU) communicates control state information of the NCR device 500A with the DU 250b (second DU) via the CU 260.

[0119] In the example of Fig. 18, the NCR device 500A installed at the cell edge of the cell C1 can be an interference source to the cell C2. Here, assuming that the gNB 200 is functionally divided into the DU 250 (two DUs 250a and 250b in the illustrated example) and the CU 260 and the NCR device 500A is controlled by the gNB 200 using DCI or MAC CE, it is considered that the DU 250a actually controls the NCR device 500A. Note that since the RRC connection of the NCR device 500A (NCR-MT520A) is terminated by the CU 260, the measurement report of the RRC of the NCR device 500A (NCR-MT520A) is managed by the CU 260.

[0120] The cell C1 is managed by the DU 250a, the cell C2 is managed by the DU 250b, and the DUs 250a and 250b are managed by the same CU 260. That is, the gNB 200 is configured by the DUs 250a and 250b and the CU 260. Each of the DUs 250a and 250b is connected to the CU 260 via the F1 interface. Since the NCR device 500A is installed at the cell edge of the cell C1, the cell C1 is a serving cell of the NCR device 500A (NCR-MT520A). The NCR device 500A relays radio signals transmitted between the cell C1 (DU 250a) and the UE 100.

[0121] 19 is a diagram showing a first operation example of the inter-cell cooperation operation according to the embodiment. The NCR device 500A (NCR-MT 520A) establishes an RRC connection with the CU 260 via the DU 250a (serving cell) (step S301). In the drawings referred to in the following embodiment, non-essential steps are indicated by dashed lines.

[0122] In step S302, the DU 250a starts control over the NCR device 500A. The control over the NCR device 500A is performed by the above-mentioned NCR control signal. In step S303, the NCR-MT 520A of the NCR device 500A controls the NCR-Fwd 510A according to the NCR control signal received from the DU 250a.

[0123] In step S304, the DU 250b may inquire of the CU 260 on the F1 interface whether or not there is a connection of the NCR device 500A. The inquiry may include a cell ID of the cell C2 managed by the DU 250b. The cell ID is used by the CU 260 to perform neighboring cell determination. The inquiry may include an RSRP threshold for the CU 260 to perform neighboring cell determination.

[0124] In step S305, the CU260 may inquire of the DU250a whether or not a connection of the NCR device 500A exists. The CU260 may notify the DU250a of an identifier of the NCR device 500A required for reporting control state information. The CU260 may determine whether the NCR device 500A is located at the cell edge of the cell C1 based on a serving cell measurement result included in an RRC measurement report from the NCR device 500A (NCR-MT520A). The CU260 may determine which neighboring cell the NCR device 500A is located near based on a neighboring cell measurement result included in the RRC measurement report.

[0125] In step S306, the DU 250a transmits a notification including information (control state information) indicating the control state of the NCR device 500A to the CU 260 on the F1 interface. For example, the control state information includes at least one of the SSB index of the beam relayed by the NCR device 500A, the control value (transmission weight, etc.) of the NCR device 500A, and the cell ID of the serving cell C1 to which the NCR device 500A is connected. The control value of the NCR device 500A is a control value according to the above-mentioned NCR control signal, and may be a control value for each slot. The control value may be a current control value.

[0126] In step S307, the CU 260 transmits a notification including the control state information from the DU 250a to the DU 250b on the F1 interface. The notification may include an identifier of the NCR device 500A and / or a cell ID of the serving cell C1 associated with the control state information.

[0127] In step S308, the DU 250b determines the influence of interference from the NCR device 500A based on the control state information from the CU 260 and the communication quality of the own cell C2.

[0128] In step S309, the DU 250b may transmit a notification including information (control state information) indicating a desired or undesired control state of the NCR device 500A to the CU 260 on the F1 interface. The control state information may be information of a recommended or unrecommended transmission weight (beam, SSB index, or angle). The control state information may be ON / OFF of relay transmission. The control state information may be a desired value of transmission power (indicating a request to lower the transmission power, or indicating a desired dB lowering). The notification may include at least one of timing information (such as a slot number), an identifier of the NCR device 500A, and a cell ID of the serving cell C1 associated with the control state information.

[0129] In step S310, the CU 260 may send a notification including the control request information from the DU 250b to the DU 250a over the F1 interface.

[0130] (1.10.2) Second example of inter-cell cooperation FIG. 20 is a diagram for explaining a second operation example of the inter-cell cooperation operation according to the embodiment. In the second operation example, the first network node is gNB200a (first gNB), and the second network node is gNB200b (second gNB). The gNB200a (first gNB) communicates control state information with the gNB200b (second gNB) via the Xn interface. FIG. 20 shows an example in which the gNB200a is functionally divided into DU250a and CU260a, and the gNB200b is functionally divided into DU250b and CU260b, but the functions may not be divided.

[0131] 21 is a diagram showing a second operation example of the inter-cell cooperation operation according to the embodiment. The NCR device 500A (NCR-MT 520A) establishes an RRC connection with the gNB 200a (step S401). In the description of the second operation example, the description of the operation overlapping with the above-mentioned first operation example will be omitted.

[0132] In step S402, the gNB 200a starts control over the NCR device 500A. The control over the NCR device 500A is performed by the above-mentioned NCR control signal. In step S403, the NCR-MT 520A of the NCR device 500A controls the NCR-Fwd 510A according to the NCR control signal received from the gNB 200a.

[0133] In step S404, the gNB 200b may inquire of the gNB 200a whether or not a connection of the NCR device 500A exists. The inquiry may include a cell ID of the cell C2 managed by the gNB 200b. The cell ID is used by the gNB 200a to perform neighboring cell determination. The inquiry may include an RSRP threshold for the gNB 200a to perform neighboring cell determination.

[0134] In step S405, the gNB 200a transmits a notification including information (control state information) indicating the control state of the NCR device 500A to the gNB 200b over the Xn interface. For example, the control state information includes at least one of the SSB index of the beam relayed by the NCR device 500A, the control value (transmission weight, etc.) of the NCR device 500A, and the cell ID of the serving cell C1 to which the NCR device 500A is connected. The control value of the NCR device 500A is a control value according to the above-mentioned NCR control signal, and may be a control value for each slot. The control value may be a current control value.

[0135] In step S406, the gNB 200b determines the effect of interference from the NCR device 500A based on the control state information from the gNB 200a and the communication quality of its own cell C2.

[0136] In step S407, the gNB 200b may transmit a notification including information (control state information) indicating a desired or undesired control state of the NCR device 500A to the gNB 200a on the Xn interface. The control state information may be information of a recommended or unrecommended transmission weight (beam, SSB index, or angle). The control state information may be ON / OFF of relay transmission. The control state information may be a desired value of transmission power (indicating a request to lower the transmission power, or indicating a desired dB lowering). The notification may include at least one of timing information (such as a slot number), an identifier of the NCR device 500A, and a cell ID of the serving cell C1 associated with the control state information.

[0137] (2) Second embodiment Next, the second embodiment will be described, mainly focusing on the differences from the above-described first embodiment. The overview of the mobile communication system 1 according to the second embodiment and the configuration of the gNB 200 are similar to those of the above-described first embodiment.

[0138] As shown in Fig. 22, the relay device according to the second embodiment is a RIS (Reconfigurable Intelligent Surface) device 500B that changes the propagation direction of an incident radio wave (wireless signal) by reflection or refraction. "NCR" in the above-mentioned first and second embodiments can be read as "RIS".

[0139] RIS is a type of repeater (hereinafter also referred to as "RIS-Fwd") that can perform beamforming (directivity control) in the same way as NCR by changing the characteristics of metamaterial. In the case of RIS, the range (distance) of the beam may also be changeable by controlling the reflection direction and / or refraction direction of each unit element. For example, the RIS may be configured to be able to control the reflection direction and / or refraction direction of each unit element and to focus (direct the beam) on a nearby UE or a distant UE.

[0140] The RIS device 500B has a new UE (hereinafter, referred to as "RIS-MT") 520B which is a control terminal for controlling the RIS-Fwd510B. The RIS-MT 520B establishes a wireless connection with the gNB 200 and performs wireless communication with the gNB 200, thereby controlling the RIS-Fwd510B in cooperation with the gNB 200. The RIS-Fwd510B may be a reflection type RIS. Such a RIS-Fwd510B changes the propagation direction of the radio waves by reflecting the incident radio waves. Here, the reflection angle of the radio waves can be variably set. The RIS-Fwd510B reflects the radio waves incident from the gNB 200 toward the UE 100. The RIS-Fwd510B may be a transmission type RIS. Such a RIS-Fwd510B changes the propagation direction of the radio waves by refracting the incident radio waves. Here, the refraction angle of the radio waves can be variably set.

[0141] FIG. 23 is a diagram showing a configuration example of RIS-Fwd510B and RIS-MT520B according to the second embodiment. RIS-MT520B has a receiving unit 521, a transmitting unit 522, and a control unit 523. Such a configuration is the same as that of the first embodiment described above. RIS-Fwd510B has a RIS511B and a RIS control unit 512B. RIS511B is a metasurface made of a metamaterial. For example, RIS511B is made by arranging structures that are very small relative to the wavelength of radio waves in an array, and it is possible to arbitrarily design the direction and / or beam shape of the reflected wave by making the structures have different shapes depending on the arrangement location. RIS511B may be a transparent dynamic metasurface. The RIS511B is configured by overlaying a transparent glass substrate on a transparent metasurface substrate on which a large number of small structures are regularly arranged, and may be capable of dynamically controlling three patterns, a mode in which the incident radio wave is transmitted, a mode in which a part of the radio wave is transmitted and a part is reflected, and a mode in which all the radio waves are reflected, by minutely moving the overlaid glass substrate. The RIS control unit 512B controls the RIS511B in response to a RIS control signal from the control unit 523 of the RIS-MT520B. The RIS control unit 512B may include at least one processor and at least one actuator. The processor decodes the RIS control signal from the control unit 523 of the RIS-MT520B and drives the actuator in response to the RIS control signal.

[0142] (3) Other embodiments In the above embodiment, an example in which the gNB 200 controls the NCR device 500A has been described. However, the NCR device 500A (NCR-MT520A) may autonomously control the NCR-Fwd510A based on the setting from the gNB 200. FIG. 24 is a diagram showing an example of beam sweeping according to another embodiment. The gNB 200 transmits a plurality of beams (in the illustrated example, beams of SSB3 to SSB5) with the same transmission weight toward the NCR device 500A for the backhaul link. The NCR device 500A (NCR-Fwd510A) autonomously transmits the plurality of beams (beams of SSB3 to SSB5) with different transmission weights toward the access link in different directions. Under such a premise, the NCR device 500A (NCR-Fwd510A) may notify the gNB200 of the operating status of the NCR-Fwd510A as appropriate, and share the operating status information of the NCR-Fwd510A with the gNB200.

[0143] The above-mentioned operation flows are not limited to being performed separately and independently, but can be performed 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 necessary to perform all steps, and only some steps may be performed.

[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 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-MT520A, RIS-MT520B) or gNB200. The program may be recorded in a computer-readable medium. Using the computer-readable medium, it is possible to install the program in a computer. Here, the computer-readable medium on which the program is recorded may be a non-transient recording medium. The non-transient recording medium is not particularly limited, and may be, for example, a recording medium such as a CD-ROM or a DVD-ROM. In addition, a circuit that executes 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] The terms "based on" and "depending on / in response to" used in this disclosure do not mean "based only on" or "depending only on", unless otherwise specified. The term "based on" means both "based only on" and "based at least in part on". Similarly, the term "depending on" means both "based only on" and "depending at least in part on". The terms "include", "comprise", and variations thereof do not mean including only the recited items, but may include only the recited items or may include additional items in addition to the recited items. Additionally, the term "or" used in this disclosure is not intended to be an exclusive or. Additionally, any reference to elements using designations such as "first", "second", etc., used in this disclosure is not intended to 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 imply that only two elements may be employed therein or that the first element must precede the second element in some manner. In this disclosure, where articles are added by translation, such as, for example, a, an, and the in English, these articles are intended to 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, etc. are possible without departing from the spirit of the invention.

[0148] This application claims priority to U.S. Provisional Application No. 63 / 395929 (filed August 8, 2022), the entire contents of which are incorporated herein by reference.

[0149] (4) Additional Notes The following additional features relate to the above-described embodiment.

[0150] (Appendix 1) A communication method for use in a mobile communication system, comprising: A base station forms multiple beams in one cell by beam sweeping; When the base station targets access restriction on only a portion of the beams among the plurality of beams, the base station broadcasts first information indicating that access restriction is being performed on a beam-by-beam basis using the portion of the beams. Communication methods.

[0151] (Appendix 2) The base station further comprises a step of broadcasting, when the cell is subject to access restriction as a whole, second information indicating that access restriction is being performed on a cell-by-cell basis, using the plurality of beams; The first information is information that is defined separately from the second information. 2. A communication method as described in claim 1.

[0152] (Appendix 3) The step of transmitting includes the step of transmitting a master information block including the first information. 3. A communication method according to claim 1 or 2.

[0153] (Appendix 4) The step of transmitting includes a step of transmitting the master information block including the first information and second information indicating that access restriction is not performed on a cell-by-cell basis. 6. A communication method as described in Appendix 3.

[0154] (Appendix 5) The method further includes a step in which a relay device that relays and transmits the part of the beams transfers the first information from the base station. 5. A communication method according to any one of claims 1 to 4.

[0155] (Appendix 6) The method further includes a step of, in response to receiving the first information, the user equipment receiving the part of the beams refraining from accessing the part of the beams and searching for other beams of the cell. 6. A communication method according to any one of claims 1 to 5.

[0156] (Appendix 7) A communication method for use in a mobile communication system, comprising: A step in which a first network node that manages a first cell controls a relay device that relays radio signals between the first network node and a user equipment in the first cell; and communicating, by the first network node, control state information relating to a control state of the relay device with a second network node managing a second cell adjacent to the first cell. Communication methods.

[0157] (Appendix 8) the first network node is a first distribution unit connected to an aggregation unit; the second network node is a second distribution unit connected to the aggregation unit; The step of communicating includes the first distributed unit communicating the control state information with the second distributed unit via the aggregation unit. 8. The communication method according to claim 7.

[0158] (Appendix 9) the first network node is a first base station; the second network node is a second base station connected to the first base station via an inter-base station interface; The step of communicating includes the step of the first base station communicating the control state information with the second distributed unit via the inter-base station interface. 8. The communication method according to claim 7.

[0159] (Appendix 10) The step of communicating includes a step of notifying the second network node of the control state information indicating a control state of the relay device under control of the first network node from the first network node. 10. A communication method according to any one of claims 7 to 9.

[0160] (Appendix 11) The method further includes a step of making an inquiry from the second network node to the first network node to request notification of the control state information. 11. The communication method according to claim 10.

[0161] (Appendix 12) The step of communicating includes a step of notifying the first network node of the control state information indicating a control state of the relay device that is desired or undesired by the second network node from the second network node. 12. A communication method according to any one of claims 7 to 11.

[0162] (5) Additional Notes introduction RAN#94e agreed on a new study item on Network Controlled Repeaters (NCR). The objectives of this study are to:

[0163] The side control information required for the network-controlled repeater is considered and defined as follows (including the assumption of maximum transmission power). -Beamforming information - Timing information for aligning transmit and receive boundaries of network-controlled repeaters - Information about UL-DL TDD configuration - ON-OFF information for efficient interference management and improved energy efficiency - Power control information for efficient interference management (as a second priority) Study and define L1 / L2 signaling (including its configuration) for transmitting side control information.

[0164] Regarding management of network controlled repeaters, consider the following: -Identification and authorization of network-controlled repeaters. Note 2: Adjustment with SA3 may be required.

[0165] This appendix discusses some initial issues for RAN2 regarding NCR.

[0166] Discussion NCR Model According to SID, the scenarios and assumptions are described as follows:

[0167] The study on NR network-controlled repeaters is to focus on the following scenarios and assumptions: - Network-controlled repeaters are in-band RF repeaters used to extend network coverage in the FR1 and FR2 bands. It is under consideration that FR2 deployment may be prioritized in both outdoor-to-indoor O2I scenarios. -Limited to single-hop static network-controlled repeaters -Network controlled repeaters are transparent to the UE -Network-controlled repeaters can simultaneously maintain links with gNBs and UEs NOTE 1: Cost-effectiveness is an important consideration for network-controlled repeaters.

[0168] RAN1#109e agreed to the following model for NCR:

[0169] Agreement A model of a network-controlled repeater in TR38.867 is shown in FIG. 25 and below. The NCR-MT is defined as a functional entity that communicates with the gNB via the control link (C-link). This allows for information exchange (e.g. side control information). The C-link is based on the NR Uu interface. Note: Side control information is at least for the control of the NCR-FW. The NCR-Fwd is defined as a functional entity that performs amplification and forwarding of UL / DL RF signals between the gNB and the UE via the backhaul link and the access link. The operation of the NCR-Fwd is controlled according to side control information received from the gNB.

[0170] According to the above description, since NCR-Fwd is an in-band RF repeater, there should be no impact on RAN2.

[0171] Observation 1: NCR-Fwd is an RF repeater and is outside the range of RAN2.

[0172] On the other hand, NCR-MT maintains a control link with the gNB and communicates side control information. NCR-MT can be considered as a special UE type similar to IAB-MT. That is, it is natural to assume that it will require support of protocols such as NAS, RRC, PDCP, RLC, MAC, PHY, etc. As a starting point, IAB-MT is considered to be a good reference for modeling NCR-MT. However, the BAP sublayer is obviously not necessary for NCR-MT, since it assumes "single-hop stationary network-controlled repeaters only", and coverage extension of the control link should be done by other means, such as using FR1 or using RF repeaters.

[0173] Proposal 1: As a starting point, RAN2 should consider IAB-MT as the basis for the NCR-MT model, and the BAP sublayer is not supported in NCR-MT.

[0174] The IAB-MT can send and receive its own traffic, including OAM traffic. The same principle applies to the NCR-MT, since the NCR may implement OAM functionality. Thus, the NCR-MT must support not only SRBs (side control information, RRC configuration, NAS connections, etc.), but also DRBs (own traffic, etc.), and the establishment of DRBs may be optional.

[0175] Proposal 2: It should be agreed that NCR-MT supports both SRB and DRB.

[0176] As shown in Figure 26, gNB instructions (e.g., side control information) are considered to be used by the NCR-MT to control the NCR-Fwd (e.g., beamforming, ON / OFF control, power control, etc.) via an internal interface, regardless of whether such an internal interface is specified.

[0177] Observation 2: The NCR-MT receives instructions from the gNB (e.g., via side control information) and controls the NCR-Fwd accordingly.

[0178] NCR Management Aspects Identification, Authentication and Access Control According to SID, RAN2 is in charge of considering the management aspects.

[0179] Consider the following aspects regarding management of network controlled repeaters: -Identification and authentication of network-controlled repeaters Note 2: Coordination with SA3 may be required.

[0180] If we consider IAB-MT as the standard as in Proposal 1, then the NCR is considered to be a network node, and therefore the same access control mechanism is considered to be applicable to NCR-MT.

[0181] The gNB provides a SIB indication to allow NCR-MT access, such as the IAB-Support IE in SIB1. NCR-MT ignores the Cell Barred IE and Intra-Freq Reselection IE in the MIB. NCR-MT ignores the following reserved cell IEs: -Cell Reserved For Future Use IE -Cell Reserved For Other Use IE (regarding cell blocking decisions) -Cell Reserved For Operator Use IE (If NCR-MT supports NPN) - NCR-MT, like the IAB Node Indication IE, sends an NCR indication upon RRC setup completion.

[0182] Proposal 3: If NCR is considered as a network node, RAN2 should agree to reuse the access control mechanism of IAB-MT, i.e., the gNB provides SIB indication and NCR-MT ignores IEs related to cell barring and cell reservation.

[0183] If NCR-MT is seen as similar to IAB-MT from RAN2's point of view, RAN2 may assume that the higher layer mechanisms of IAB-MT are reused for NCR-MT as well, e.g., with regard to authentication.

[0184] Observation 3: RAN2 can assume that the higher layer mechanisms of IAB-MT are reused for NCR-MT, e.g., in terms of authentication.

[0185] NCR Ability Signals Another issue with management is that NCR-Fwd FSince it is a peer, i.e. there is no protocol support, how does the gNB know the capabilities of the NCR-Fwd, such as operating frequency, number and resolution of beamforming, output power and dynamic range, etc. It is quite simple for the NCR-MT to inform the gNB of the capabilities of the connected NCR-Fwd in addition to its own (i.e. NCR-MT) capabilities.

[0186] Proposal 4: RAN2 should agree that NCR-MT should notify gNB of its NCR-Fwd capabilities. The capabilities to be reported need further consideration.

[0187] Multibeam NCR It is also worth considering whether the NCR can handle multiple beams, as shown in Figure 27. This is expected to improve spectral efficiency, enhance coverage, and provide scheduling flexibility for multiple UEs.

[0188] A simple RF repeater does not have resource block selectivity and amplifies and forwards all signals within the system bandwidth with a single weight. On the other hand, some advanced RF repeaters may manage multiple beams for multiple UEs. It is therefore important that the Rel-18 NCR supports the implementation of such advanced RF repeaters.

[0189] Proposal 5: RAN2 should agree to manage the NCR, which allows the gNB to process multiple beams simultaneously for different UEs.

[0190] If multi-beam NCR is supported, from the RAN2 point of view, a discussion may arise as to whether one NCR node (or one NCR-MT) can support multiple NCR-Fwds. Similarly, an additional consideration may be whether one NCR-Fwd can control multiple "antenna sets". These options are shown in Figure 28.

[0191] Multiple NCR-Fwds or multiple antenna sets can process different beams for different UEs using different resource blocks in the same slot (as shown in Figure 27). In case of multiple NCR-Fwds, the NCR needs to process different weights dictated by the gNB for each NCR-Fwd at the same time.

[0192] Another possible scenario is that the NCR is controlled by multiple gNBs, for example when the NCR is deployed at the cell edge, in which case multiple NCR-Fwds are needed to handle different beams for different access links belonging to different gNBs.

[0193] These cases may affect the design of NCR management and side control information, so RAN2 needs to discuss management models to allow different implementations of multi-beam NCR.

[0194] Note: RAN1 decides whether multiple NCR-Fwds are co-located (e.g. for spatial diversity gain). Even if multiple Fwds are not co-located, RAN1 should assume that the control link and backhaul link share the same radio channel conditions. This is implied in the decision in RAN#96.

[0195] Proposal 6: RAN2 should discuss the management model of repeaters with multiple beams, for example, whether one NCR-MT can control multiple NCR-Fwds, or whether one NCR-Fwd can support multiple antenna sets.

[0196] Side Control Information RAN1 discusses the overall concept and function of side control information, such as beam information, TDD UL / DL configuration, timing of DL reception and UL transmission, ON-OFF information, etc. From the RAN2 point of view, it is assumed that dynamic and semi-static control may be indicated by DCI and MAC CE (or a combination of these), respectively. Furthermore, static configuration should be done by RRC. For detailed design of side control information, RAN2 needs to wait for the progress of RAN1.

[0197] Observation 4: Side control information may need to extend DCI, MAC CE, and / or RRC signaling. RAN2 needs to wait for further developments of RAN1.

[0198] Deployment Assumptions In RAN#96, support for multiple frequencies was discussed, but it was decided that the operating frequencies of the control links would be restricted to the same as the backhaul links.

[0199] RAN Chair: The RAN1 discussion will focus solely on in-band.

[0200] It is believed that the intention is to simplify procedures for the control link by leveraging the same channel conditions as the backhaul link.

[0201] Observation 5: When the control link and backhaul link operate on the same frequency, the wireless channel conditions are the same.

[0202] On the other hand, it is also worth considering whether the NCR-MT can support Carrier Aggregation (CA) and Dual Connectivity (DC). For example, the NCR-MT may configure a SCell (for side control information) in FR2 with the same frequency as a PCell (for RRC connection) in FR1, as shown in Figure 29.

[0203] The CA / DC configuration of NCR-MT is not considered to violate the RAN plenary decision as long as the SCell for the control link operates on the same frequency as the NCR-Fwd for the backhaul link. Furthermore, the robust RRC connection on FR1 / PCell brings various advantages considering that the NCR is a network node. This is very similar to the CP / UP split configuration specified by the IAB.

[0204] Proposal 7: RAN2 should consider the possibility that NCR-MT is configured with Carrier Aggregation (CA) and / or Dual Connectivity (DC). At least one SCell should be configured to operate on the same frequency as NCR-Fwd. [Explanation of symbols]

[0205] 1: Mobile communication systems 100:UE 200: gNB 210: Transmission unit 220: Receiving unit 230: Control section 240: Backhaul communication unit 500A:NCR device 500B :RIS device 511A: Wireless unit 511a: Antenna section 511b :RF circuit 511c: Directivity control unit 512A: NCR control unit 512B: RIS control unit 521: Receiving unit 522: Transmission unit 523: Control unit 530: Interface

Claims

1. A communication method for use in a mobile communication system, comprising: A base station broadcasts relay device support information indicating that the base station supports a control terminal included in the relay device, or access restriction information for restricting access from the terminal; determining, by the control terminal, in response to receiving the relay device support information, that access to the base station is permitted; The control terminal ignores the access restriction information from the base station. Communication methods.

2. The method further comprises the step of: the control terminal transmitting control terminal information indicating that the control terminal is a control terminal to the base station. The communication method according to claim 1 .

3. The control terminal further supports OAM (Operation, Administration, and Maintenance) and supports establishment of SRB (Signaling Radio Bearer) and DRB (Data Radio Bearer) between the control terminal and the base station. The communication method according to claim 1 .

4. In a mobile communication system, a relay device having a repeater and a control terminal, The control terminal determines that access to the base station is permitted in response to receiving relay device support information broadcast from the base station, the relay device support information indicating that the control terminal is supported; The control terminal ignores access restriction information from the base station that restricts access from the terminal. Relay device.

5. A mobile communication system comprising a base station, a relay device having a repeater and a control terminal, and a terminal, The base station broadcasts relay device support information indicating that the base station supports the control terminal, or access restriction information for restricting access from the terminal; the control terminal determines that access to the base station is permitted in response to receiving the relay device support information; The control terminal ignores the access restriction information from the base station. system.

6. In a mobile communication system, a relay device having a repeater and a control terminal, A process of determining that access to the base station is permitted in response to reception of relay device support information broadcast from the base station, the relay device support information indicating that the control terminal is supported; and executing a process of ignoring access restriction information from the base station that restricts access from the terminal. program.

7. In a mobile communication system, a chip set for a relay device having a repeater and a control terminal, comprising: A process of determining that access to the base station is permitted in response to reception of relay device support information broadcast from the base station, the relay device support information indicating that the control terminal is supported; and executing a process of ignoring access restriction information from the base station that restricts access from the terminal. Chipset.

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