Communication system

Abstract

The communication system of the present invention comprises: a base station applied to a 5th generation wireless access system; and a relay device having a beamforming function and performing relay processing between the base station and the communication terminal, the base station transmitting information on a beam used in the relay processing to the relay device and further transmitting a reference signal used in measurement for movement control of the communication terminal, and when the reference signal is received, transmitting the information on the beam used in the relay processing to the relay device. The repeater forms a beam on the basis of information relating to the beam received from the base station and transmits the reference signal to the communication terminal, and when the measurement result of the reference signal is received from the communication terminal, the repeater relays the measurement result of the reference signal to the base station.

Description

Technical Field

[0001] The present disclosure relates to wireless communication technology. Background Art

[0002] In 3GPP (3rd Generation Partnership Project), a standardization organization for mobile communication systems, the fifth generation (sometimes referred to as "5G") wireless access system is being discussed as a successor to Long Term Evolution (LTE) and Long Term Evolution Advanced (LTE-A), one of the fourth generation wireless access systems (see Non-Patent Document 1) (for example, Non-Patent Document 2). The technology for the wireless section of 5G is called "New Radio Access Technology" ("New Radio" is abbreviated as "NR"). The NR system is discussed based on the LTE system and the LTE-A system.

[0003] For example, in Europe, the METIS organization is summarizing the requirements for 5G (see non-patent document 3). In the 5G wireless access system, the system capacity is 1000 times that of the LTE system, the data transmission speed is 100 times, the data processing delay is 1 / 5, and the number of simultaneous connections of communication terminals is 100 times. The conditions for achieving further low power consumption and low cost of the device can be listed as requirements (see non-patent document 3).

[0004] In order to meet such requirements, discussions on 5G standards are progressing in 3GPP (see non-patent documents 4 to 23).

[0005] As the access method of NR, OFDM (Orthogonal Frequency Division Multiplexing) is used in the downlink direction, and OFDM and DFT-s-OFDM (Discrete Fourier Transform-spread-OFDM) are used in the uplink direction. In addition, like LTE and LTE-A, the 5G system does not include line switching, but only packet communication.

[0006] In NR, higher frequencies can be used compared to LTE to increase transmission speeds and reduce processing delays.

[0007] In NR, which sometimes uses higher frequencies than LTE, a narrower beam-shaped transmission and reception range is formed (beamforming) and the direction of the beam is changed (beam scanning), thereby attempting to ensure cell coverage.

[0008] use Figure 1 This article explains the decisions made by 3GPP regarding the frame structure of the NR system as described in Non-Patent Document 1 (Chapter 5). Figure 1 This is an explanatory diagram showing the structure of a wireless frame used in a communication system using the NR method. Figure 1 In NR, one radio frame is 10ms. The radio frame is divided into 10 subframes of equal size. The frame structure of NR supports one or more parameter sets (Numerology), that is, one or more subcarrier spacings (Subcarrier spacing: SCS). In NR, one subframe is 1ms, and one time slot consists of 14 code elements, regardless of the subcarrier spacing. In addition, the number of time slots contained in one subframe is one when the subcarrier spacing is 15kHz, and the number of time slots in other subcarrier spacings increases in proportion to the subcarrier spacing (refer to non-patent document 11 (3GPP TS38.211)).

[0009] Non-Patent Document 2 (Chapter 5) and Non-Patent Document 11 record the decisions made by 3GPP regarding the channel structure in the NR system.

[0010] The Physical Broadcast Channel (PBCH) is a channel used for downlink transmission from a base station device (hereinafter sometimes referred to as "base station") to a communication terminal device (hereinafter sometimes referred to as "communication terminal" or "terminal") such as a mobile terminal device (hereinafter sometimes referred to as "mobile terminal"). The PBCH is transmitted together with a downlink synchronization signal.

[0011] The downlink synchronization signal in NR has a first synchronization signal (Primary Synchronization Signal: P-SS) and a second synchronization signal (Secondary Synchronization Signal: S-SS). The synchronization signal is sent from the base station as a synchronization signal burst (Synchronization Signal Burst: sometimes referred to as SS burst below) at a specified period for a specified duration. The SS burst consists of a synchronization signal block (Synchronization Signal Block; sometimes referred to as SS block below) for each beam of the base station.

[0012] The base station changes the beam during the duration of the SS burst to transmit the SS block of each beam. The SS block consists of P-SS, S-SS and PBCH.

[0013] The Physical Downlink Control Channel (PDCCH) is a channel for downlink transmission from the base station to the communication terminal. PDCCH transmits downlink control information (DCI). DCI includes resource allocation information for the downlink shared channel (DL-SCH), which is one of the transmission channels described later, resource allocation information for the paging channel (PCH), which is one of the transmission channels described later, and HARQ (Hybrid Automatic Repeat reQuest) information related to DL-SCH. In addition, DCI sometimes includes an uplink scheduling grant. DCI sometimes includes a response signal for uplink transmission, namely Ack (Acknowledgement) / Nack (Negative Acknowledgement). In addition, in order to flexibly switch DL / UL within a time slot, DCI sometimes includes a time slot format indication (Slot Format Indication: SFI). PDCCH or DCI is also called L1 / L2 control signal.

[0014] In NR, a time domain and a frequency domain are provided as candidates for including PDCCH. This area is called a control resource set (CORESET). The communication terminal monitors CORESET and acquires PDCCH.

[0015] The Physical Downlink Shared Channel (PDSCH) is a downlink transmission channel from a base station to a communication terminal. A downlink shared channel (DL-SCH) as a transport channel and a PCH as a transport channel are mapped to the PDSCH.

[0016] The Physical Uplink Control Channel (PUCCH) is a channel for uplink transmission from the communication terminal to the base station. PUCCH transmits uplink control information (UCI). UCI includes response information (response signal) for downlink transmission, namely Ack / Nack, CSI (Channel State Information), scheduling request (SR), etc. CSI is composed of RI (Rank Indicator), PMI (Precoding Matrix Indicator), and CQI (Channel Quality Indicator) reports. RI refers to the rank information of the channel matrix in MIMO (Multiple Input Multiple Output). PMI refers to the information of the precoding waiting matrix used in MIMO. CQI is quality information indicating the quality of the received data or the quality of the communication line. UCI is sometimes transmitted through the PUSCH described later. PUCCH or UCI is also called L1 / L2 control signal.

[0017] The physical uplink shared channel (PUSCH) is a channel for uplink transmission from a communication terminal to a base station. An uplink shared channel (UL-SCH), which is one of the transport channels, is mapped to the PUSCH.

[0018] The Physical Random Access Channel (PRACH) is a channel for uplink transmission from a communication terminal to a base station. The PRACH transmits a random access preamble.

[0019] The downlink reference signal (Reference Signal: RS) is a codeword known as a communication system of the NR mode. The following four downlink reference signals are defined. The UE-specific Reference Signal (UE-specific Reference Signal) is the data demodulation reference signal (Demodulation Reference Signal: DM-RS), the phase tracking reference signal (Phase Tracking Reference Signal: PT-RS), the positioning reference signal (Positioning Reference Signal: PRS), and the channel state information reference signal (Channel State Information Reference Signal: CSI-RS). As a measurement of the physical layer of the communication terminal, there are reference signal received power (Reference Signal Received Power: RSRP) measurement and reference signal received quality (Reference Signal Received Quality: RSRQ) measurement.

[0020] The uplink reference signal is also a symbol known as a communication system of the NR method. The following three types of uplink reference signals are defined: data demodulation reference signal (Demodulation Reference Signal: DM-RS), phase tracking reference signal (Phase Tracking Reference Signal: PT-RS), and sounding reference signal (Sounding Reference Signal: SRS).

[0021] The transport channel described in Non-Patent Document 2 (Chapter 5) is described below. The broadcast channel (BCH) in the downlink transport channel is broadcast to the entire coverage area of ​​its base station (cell). The BCH is mapped to the physical broadcast channel (PBCH).

[0022] HARQ-based retransmission control is applied to the downlink shared channel (DL-SCH). DL-SCH can broadcast to the entire coverage area of ​​the base station (cell). DL-SCH supports dynamic or quasi-static resource allocation. Quasi-static resource allocation is also called semi-persistent scheduling. DL-SCH supports discontinuous reception (DRX) of communication terminals in order to reduce power consumption of communication terminals. DL-SCH is mapped to the physical downlink shared channel (PDSCH).

[0023] The Paging Channel (PCH) supports DRX of the communication terminal in order to reduce the power consumption of the communication terminal. The PCH is requested to be broadcast to the entire coverage area of ​​the base station (cell). The PCH is mapped to a physical resource such as the Physical Downlink Shared Channel (PDSCH) that can be dynamically used for traffic.

[0024] Retransmission control using HARQ is applied to the uplink shared channel (UL-SCH) in the uplink transmission channel. UL-SCH supports dynamic or quasi-static resource allocation. Quasi-static resource allocation is also called configured grant. UL-SCH is mapped to the physical uplink shared channel (PUSCH).

[0025] The Random Access Channel (RACH) is limited to control information. There is a risk of collision in the RACH. The RACH is mapped to the Physical Random Access Channel (PRACH).

[0026] The following is an explanation of HARQ. HARQ is a technology that improves the communication quality of a transmission line by combining Automatic RepeatreQuest (ARQ) and Forward Error Correction (Forward Error Correction). HARQ has the following advantages: even for a transmission line with changed communication quality, error correction can be effectively used by retransmission. In particular, when retransmission is performed, the quality can be further improved by synthesizing the reception result of the first transmission and the reception result of the retransmission.

[0027] An example of the retransmission method is described below. When the receiving side cannot correctly decode the received data, in other words, when a CRC (Cyclic Redundancy Check) error occurs (CRC=NG), "Nack" is sent from the receiving side to the sending side. The sending side that receives "Nack" retransmits the data. When the receiving side can correctly decode the received data, in other words, when no CRC error occurs (CRC=OK), "Ack" is sent from the receiving side to the sending side. The sending side that receives "Ack" sends the next data.

[0028] Other examples of the retransmission method are described. When a CRC error occurs on the receiving side, a retransmission request is made from the receiving side to the sending side. The retransmission request is made by switching the NDI (New Data Indicator). The sending side that receives the retransmission request retransmits the data. When no CRC error occurs on the receiving side, no retransmission request is made. When the sending side does not receive a retransmission request within a specified time, it is deemed that no CRC error is sent on the receiving side.

[0029] The logical channel described in Non-Patent Document 1 (Chapter 6) is described below. The Broadcast Control Channel (BCCH) is a downlink channel for broadcasting system control information. The BCCH as a logical channel is mapped to the Broadcast Channel (BCH) as a transport channel or the Downlink Shared Channel (DL-SCH).

[0030] The Paging Control Channel (PCCH) is a downlink channel for transmitting changes in paging information (PagingInformation) and system information (SystemInformation). The PCCH, which is a logical channel, is mapped to the Paging Channel (PCH), which is a transport channel.

[0031] The Common Control Channel (CCCH) is a channel used to send control information between a communication terminal and a base station. The CCCH is used when there is no RRC connection between the communication terminal and the network. In the downlink direction, the CCCH is mapped to the downlink shared channel (DL-SCH) as a transport channel. In the uplink direction, the CCCH is mapped to the uplink shared channel (UL-SCH) as a transport channel.

[0032] Dedicated Control Channel (DCCH) is a channel used to send dedicated control information between a communication terminal and a network in a point-to-point manner. DCCH is used when there is an RRC connection between a communication terminal and a network. DCCH is mapped to the uplink shared channel (UL-SCH) in the uplink and to the downlink shared channel (DL-SCH) in the downlink.

[0033] Dedicated Traffic Channel (DTCH) is a channel used to send user information and perform point-to-point communication with communication terminals. DTCH exists in both uplink and downlink. DTCH is mapped to the uplink shared channel (UL-SCH) in the uplink and to the downlink shared channel (DL-SCH) in the downlink.

[0034] The location tracking of the communication terminal is performed in units of an area consisting of one or more cells. The location tracking is performed to track the location of the communication terminal even in the standby state, so as to call the communication terminal. In other words, it is performed to call the communication terminal. The area used for the location tracking of the communication terminal is called a tracking area (TA).

[0035] NR supports calling of communication terminals within a range smaller than the tracking area. This range is called RAN Notification Area (RNA). Paging of communication terminals in the RRC_INACTIVE state described later is performed within this range.

[0036] In order to support wider frequency bandwidths (transmission bandwidths), carrier aggregation (CA) of aggregating (also called "aggregation") two or more component carriers (CC) is being studied in NR. CA is described in Non-Patent Document 1.

[0037] In the case of CA, the UE as a communication terminal has a unique RRC connection (RRC connection) with the network (Network: NW). In the RRC connection, one service cell provides NAS mobility information and security input. This cell is called the primary cell (Primary Cell: PCell). According to the capabilities (capability) of the UE, a secondary service cell (Secondary Cell: SCell) is formed to form a group of service cells together with the PCell. For one UE, a group of service cells consisting of one PCell and one or more SCells is formed.

[0038] In addition, in 3GPP, there is a dual connectivity (DC) in which a UE connects to two base stations for communication, in order to further increase the communication capacity. DC is described in Non-Patent Documents 1 and 22.

[0039] Sometimes one of the base stations performing dual connectivity (DC) is called the "master base station (Master Node: MN)", and the other is called the "secondary base station (Secondary Node: SN)". The service cells formed by the master base station are sometimes collectively referred to as the master cell group (Master Cell Group: MCG), and the service cells formed by the secondary base stations are sometimes collectively referred to as the secondary cell group (Secondary Cell Group: SCG). In DC, the main cell in the MCG or SCG is called a special cell (Special Cell: SpCell or SPCell). The special cell in the MCG is called PCell, and the special cell in the SCG is called the primary SCG cell (PSCell).

[0040] In addition, in NR, the base station pre-sets a part of the carrier frequency band for the UE (hereinafter sometimes referred to as Bandwidth Part: bandwidth part (BWP)), and the UE transmits and receives between itself and the base station in the BWP, thereby being able to reduce power consumption in the UE.

[0041] In addition, in 3GPP, the use of side link (SL) communication (also called PC5 communication) is supported in both the EPS (Evolved Packet System) and the 5G core system described later (see non-patent documents 1, 2, 26 to 28). In SL communication, communication is performed between terminals. As services using SL communication, there are, for example, V2X (Vehicle-to-everything) services and proxy services. In SL communication, not only direct communication between terminals, but also communication between UE and NW via relay is proposed (see non-patent documents 26 and 28).

[0042] The physical channels used for SL are described below (see Non-Patent Documents 2 and 11). The physical sidelink broadcast channel (PSBCH) transmits information related to system synchronization and is sent from the UE.

[0043] The physical sidelink control channel (PSCCH) transmits control information from the UE for sidelink communication and V2X sidelink communication.

[0044] The physical sidelink shared channel (PSSCH) transmits data from the UE for sidelink communication and V2X sidelink communication.

[0045] The physical sidelink feedback channel (PSFCH) transmits HARQ feedback on the sidelink from the UE that receives the PSSCH transmission to the UE that sends the PSSCH.

[0046] The transport channel used for SL will be described below (see Non-Patent Document 1). The sidelink broadcast channel (SL-BCH) has a predetermined transport channel format and is mapped to the PSBCH which is a physical channel.

[0047] The sidelink shared channel (SL-SCH) supports broadcast transmission. SL-SCH supports both UE autonomous resource selection and resource allocation scheduled by the base station. There is a risk of conflict in UE autonomous resource selection, but there is no conflict when the UE is allocated dedicated resources by the base station. In addition, SL-SCH supports dynamic link adaptation by changing the transmission power, modulation, and coding. SL-SCH is mapped to PSSCH, which is a physical channel.

[0048] The logical channels used for SL are described below (see Non-Patent Document 2). The Sidelink Broadcast Control Channel (SBCCH) is a sidelink channel used to broadcast sidelink system information from one UE to other UEs. The SBCCH is mapped to the SL-BCH which is a transport channel.

[0049] Sidelink Traffic Channel (STCH) is a one-to-many sidelink traffic channel used to send user information from one UE to other UEs. STCH is only used by UEs with sidelink communication capabilities and UEs with V2X sidelink communication capabilities. One-to-one communication between two UEs with sidelink communication capabilities is also achieved through STCH. STCH is mapped to SL-SCH, which is a transport channel.

[0050] A sidelink control channel (SCCH) is a sidelink control channel for transmitting control information from one UE to other UEs. The SCCH is mapped to the SL-SCH which is a transport channel.

[0051] In LTE, SL communication is only broadcast. In NR, in addition to broadcast, support for unicast and groupcast is also being studied as SL communication (see Non-Patent Document 27 (3GPP TS23.287)).

[0052] In SL's unicast and multicast communications, HARQ feedback (Ack / Nack), CSI reporting, etc. are supported.

[0053] In addition, 3GPP is studying Integrated Access and Backhaul (IAB) in which both an access link as a link between a UE and a base station and a backhaul link as a link between base stations are wirelessly performed (see Non-Patent Documents 2, 20, and 29).

[0054] 3GPP has proposed some new technologies. For example, it has proposed to introduce smart repeaters (repeaters capable of beam steering) (Non-Patent Document 30). A control method for controlling smart repeaters from a base station is being studied. Prior art literature Non-patent literature

[0055] Non-patent document 1: 3GPP TS36.300 V16.7.0 Non-patent document 2: 3GPP TS38.300 V16.8.0 Non-patent document 3: “Scenarios, requirements and KPIs for 5G mobile and wireless system”, ICT-317669-METIS / D1.1 Non-patent document 4: 3GPP TR23.799 V14.0.0 Non-patent document 5: 3GPP TR38.801 V14.0.0 Non-patent document 6: 3GPP TR38.802 V14.2.0 Non-patent document 7: 3GPP TR38.804 V14.0.0 Non-patent document 8: 3GPP TR38.912 V16.0.0 Non-patent document 9: 3GPP RP-172115 Non-patent document 10: 3GPP TS23.501 V17.3.0 Non-patent document 11: 3GPP TS38.211 V17.0.0 Non-patent document 12: 3GPP TS38.212 V17.0.0 Non-patent document 13: 3GPP TS38.213 V17.0.0 Non-patent document 14: 3GPP TS38.214 V17.0.0 Non-patent document 15: 3GPP TS38.321 V16.7.0 Non-patent document 16: 3GPP TS38.322 V16.2.0 Non-patent document 17: 3GPP TS38.323 V16.6.0 Non-patent document 18: 3GPP TS37.324 V16.3.0 Non-patent document 19: 3GPP TS38.331 V16.7.0 Non-patent document 20: 3GPP TS38.401 V16.8.0 Non-patent document 21: 3GPP TS38.413 V16.8.0 Non-patent document 22: 3GPP TS37.340 V16.8.0 Non-patent document 23: 3GPP TS38.423 V16.8.0 Non-patent document 24: 3GPP TS38.305 V16.7.0 Non-patent document 25: 3GPP TS23.273 V17.3.0 Non-patent document 26: 3GPP TR23.703 V12.0.0 Non-patent document 27: 3GPP TS23.287 V17.2.0 Non-patent document 28: 3GPP TS23.303 V17.0.0 Non-patent document 29: 3GPP TS38.340 V16.5.0 Non-patent document 30: 3GPP RP-213700 Non-patent document 31: 3GPP RP-201831 Non-patent document 32: 3GPP TS38.215 V17.1.0 Non-patent document 33: 3GPP TS38.455 V17.0.0 Non-patent document 34: 3GPP TS37.355 V17.0.0 Summary of the invention Technical problem to be solved by the invention

[0056] In the 5G wireless access system, communications are performed for a variety of services. In order to make such communications possible, support for communications using, for example, smart repeaters is also under study. In addition, the movement of UEs connected to base stations via smart repeaters is also explored. However, measurements (reception quality measurements) are required during movement, and when the UE is connected to a base station via a smart repeater, the objects and processes of the measurements are not disclosed. As a result, the following problems arise: the UE cannot perform measurements, and the base station cannot control the beam of the smart repeater, resulting in the UE being unable to connect to the base station via the smart repeater.

[0057] In view of the above problems, one of the objects of the present disclosure is to enable the mobility of UE connected to a base station via a smart repeater and to realize a communication system with higher reliability. Technical means for solving technical problems

[0058] The communication system includes: a base station, which is applied to a fifth generation wireless access system; and a repeater, which has a beamforming function and performs relay processing between the base station and a communication terminal. The base station sends information related to the beam used in the relay processing to the repeater, and further sends a reference signal used in the measurement of the mobility control of the communication terminal. When receiving the reference signal, the repeater forms a beam based on the information related to the beam received from the base station and sends the reference signal to the communication terminal, and when receiving the measurement result of the reference signal from the communication terminal, the repeater relays the measurement result of the reference signal to the base station. Effects of the Invention

[0059] According to the present disclosure, it is possible to enable movement of UE connected to a base station via a smart repeater, and to realize a communication system with higher reliability.

[0060] The objects, features, aspects and advantages of the present disclosure will become more apparent through the following detailed description and accompanying drawings. In the following description, the intelligent repeater is referred to as a "repeater" for short. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 This is an explanatory diagram showing the structure of a wireless frame used in a communication system using the NR method. Figure 2 This is a block diagram showing the overall structure of the NR-based communication system 210 discussed in 3GPP. Figure 3 This is a structural diagram of the DC based on the base station connected to the NG core. Figure 4 Yes means Figure 2 A block diagram of the structure of the mobile terminal 202 is shown. Figure 5 Yes means Figure 2 A block diagram of the structure of the base station 213 is shown. Figure 6 It is a block diagram showing the structure of the 5GC unit. Figure 7 This is a flowchart showing an overview of the cell search and standby actions performed by a communication terminal (UE) in a communication system using the NR mode. Figure 8 is a diagram showing an example of a cell structure in an NR system. Fig. 9 It is a connection structure diagram showing an example of the connection structure of the terminal in SL communication. Fig.10 is a connection structure diagram showing an example of a connection structure of a base station supporting access backhaul integration. Fig.11 This is a diagram showing a measurement signal transmitted from a base station in accordance with Embodiment 1. Fig.12 This is a diagram showing an example of an operation sequence of L1 measurement of a UE connected to a base station via a relay, in accordance with Embodiment 1. Fig.13 This is a diagram showing an example of an action sequence of L3 measurement of a UE connected to a base station via a relay, regarding Embodiment 1. Fig.14 This is a diagram showing another example of the operation sequence of L1 measurement in the repeater in accordance with the first embodiment. Fig.15 This is a diagram showing another example of the operation sequence of L1 measurement in the repeater in accordance with the first embodiment. Fig.16 This is a diagram showing another example of the operation sequence of L3 measurement in a repeater in relation to the first embodiment. Fig.17 This is a diagram showing a measurement signal transmitted from a repeater in accordance with Embodiment 1. Fig.18 This is a diagram showing an example of an operation sequence of L1 measurement of a UE connected to a base station via a relay, in accordance with Embodiment 1. Fig.19 This is a diagram showing an example of an action sequence of L3 measurement of a UE connected to a base station via a relay, regarding Embodiment 1. Fig. 20 This is a diagram showing an example of a sequence of actions in which a UE connected to a base station via a relay transmits an SRS and the SRS is received by the base station, in relation to Embodiment 2. Fig.21 This is a diagram showing an example of a sequence of actions in which a UE connected to a base station via a relay transmits an SRS and the SRS is received by the relay, in relation to Embodiment 2. Fig. 22 This is a diagram showing an example of a sequence of actions in which a relay transmits an SRS and a base station receives the SRS, in accordance with Embodiment 2. DETAILED DESCRIPTION

[0062] Implementation method 1. Figure 2 2 is a block diagram showing the overall structure of a communication system 210 using the NR method discussed in 3GPP. Figure 2For explanation. The radio access network is called NG-RAN (Next Generation Radio Access Network: Next Generation Radio Access Network) 211. The communication terminal device, namely the mobile terminal device (hereinafter referred to as "mobile terminal (User Equipment: UE)") 202 can wirelessly communicate with the base station device (hereinafter referred to as "NR base station (NG-RAN NodeB: gNB)") 213, and use wireless communication to send and receive signals. NG-RAN 211 is composed of one or more NR base stations 213.

[0063] Here, the "communication terminal device" includes not only mobile terminal devices such as mobile phone terminal devices that can be moved, but also non-mobile devices such as sensors. In the following description, the "communication terminal device" may be simply referred to as a "communication terminal".

[0064] The AS (Access Stratum) protocol is terminated between UE 202 and NG-RAN 211. As the AS protocol, for example, RRC (Radio Resource Control), SDAP (Service Data Adaptation Protocol), PDCP (Packet Data Convergence Protocol), RLC (Radio Link Control), MAC (Medium Access Control), and PHY (Physical layer) are used. RRC is used for the control layer (hereinafter, sometimes also referred to as C layer or C-Plane), SDAP is used for the user layer (hereinafter, sometimes also referred to as U layer or U-Plane), and PDCP, MAC, RLC, and PHY are used for both the C layer and the U layer.

[0065] The control protocol RRC (Radio Resource Control) between UE202 and NR base station 213 performs broadcast, paging, RRC connection management, etc. The states between NR base station 213 and UE 202 in RRC include RRC_IDLE, RRC_CONNECTED, and RRC_INACTIVE.

[0066] In RRC_IDLE, PLMN (Public Land Mobile Network) selection, system information (System Information: SI) broadcasting, paging, cell reselection, movement, etc. are performed. In RRC_CONNECTED, the mobile terminal has an RRC connection and can send and receive data with the network. In addition, in RRC_CONNECTED, handover (Handover: HO), measurement of neighbor cells, etc. are performed. RRC_INACTIVE maintains the connection between the 5G core unit 214 and the NR base station 213, while broadcasting system information (System Information: SI), paging, cell reselection, movement, etc.

[0067] The gNB 213 is connected to the 5G core unit (hereinafter sometimes referred to as the "5GC unit") 214 including the Access and Mobility Management Function (AMF), the Session Management Function (SMF), or the User Plane Function (UPF) through the NG interface. Communication of control information and / or user data is performed between the gNB 213 and the 5GC unit 214. The NG interface is a general term for the N2 interface between the gNB 213 and the AMF 220, the N3 interface between the gNB 213 and the UPF 221, the N11 interface between the AMF 220 and the SMF 222, and the N4 interface between the UPF 221 and the SMF 222. One gNB 213 can be connected to multiple 5GC units 214. The gNBs 213 are connected to each other through the Xn interface, and communication of control information and / or user data is performed between the gNBs 213.

[0068] The 5GC unit 214 is an upper device, specifically, an upper node, and controls the connection between the NR base station 213 and the mobile terminal (UE) 202, allocates paging signals to one or more NR base stations (gNB) 213 and / or LTE base stations (E-UTRAN NodeB: eNB), etc. In addition, the 5GC unit 214 performs mobility control (Mobility Control) in the idle state (Idle State). The 5GC unit 214 manages the tracking area (Tracking Area) list when the mobile terminal 202 is in the idle state, in the inactive state (Inactive State) and in the active state (Active State). The 5GC unit 214 starts the paging protocol by sending a paging message to the cell belonging to the tracking area (Tracking Area) where the mobile terminal 202 is registered (registered).

[0069] gNB 213 can constitute one or more cells. When one gNB 213 constitutes multiple cells, each cell is configured to be able to communicate with UE 202.

[0070] gNB213 can be divided into a central unit (Central Unit: sometimes referred to as CU below) 215 and a distributed unit (Distributed Unit: sometimes referred to as DU below) 216. CU 215 is configured as one in gNB 213. DU 216 is configured as one or more in gNB213. One DU 216 constitutes one or more cells. CU 215 is connected to DU 216 via an F1 interface, and control information and / or user data are communicated between CU 215 and DU 216. The F1 interface is composed of an F1-C interface and an F1-U interface. CU 215 assumes the functions of each protocol of RRC, SDAP, and PDCP, and DU 216 assumes the functions of each protocol of RLC, MAC, and PHY. One or more TRPs (Transmission Reception Point: sending and receiving points) 219 are sometimes connected to DCU216. TR 219 sends and receives wireless signals to and from UE.

[0071] The CU 215 may be divided into a C-layer CU (CU-C) 217 ​​and a U-layer CU (CU-U) 218. The CU-C 217 is configured as one in the CU 215. The CU-U 218 is configured as one or more in the CU 215. The CU-C 217 is connected to the CU-U 218 via an E1 interface, and control information is communicated between the CU-C 217 and the CU-U 218. The CU-C 217 is connected to the DU 216 via an F1-C interface, and control information is communicated between the CU-C 217 and the DU 216. The CU-U 218 is connected to the DU 216 via an F1-U interface, and user data is communicated between the CU-U 218 and the DU 216.

[0072] The 5G communication system may include the Unified Data Management (UDM) function and the Policy Control Function (PCF) described in Non-Patent Document 10 (3GPP TS23.501). UDM and / or PCF may be included in Figure 2 In the 5GC section 214.

[0073] In a 5G communication system, a location management function (LMF) described in non-patent document 24 (3GPP TS38.305) may be provided. As disclosed in non-patent document 25 (3GPP TS23.273), the LMF may be connected to a base station via an AMF.

[0074] The 5G communication system may include a non-3GPP interworking function (N3IWF) described in non-patent document 10 (3GPP TS23.501). The N3IWF can terminate the access network (AN) between the UE and the UE in the non-3GPP access between the UE and the UE.

[0075] Figure 3 This is a diagram showing a structure based on DC (dual connection) connected to the NG core. Figure 3 In the figure, the solid line represents the connection of U-Plane, and the dotted line represents the connection of C-Plane. Figure 3 In the example, the primary base station 240-1 can be a gNB or an eNB. In addition, the secondary base station 240-2 can be a gNB or an eNB. Figure 3 In the present invention, the DC structure in which the primary base station 240-1 is a gNB and the secondary base station 240-2 is an eNB is sometimes referred to as NG-EN-DC. Figure 3 In the example, the U-Plane connection between the 5GC unit 214 and the auxiliary base station 240-2 is performed via the main base station 240-1, but it can also be performed directly between the 5GC unit 214 and the auxiliary base station 240-2. Figure 3 In the present invention, the core network connected to the LTE system and the LTE-A system, namely the EPC (Evolved Packet Core), can be connected to the main base station 240-1 instead of the 5GC unit 214. The U-Plane connection between the EPC and the auxiliary base station 240-2 can be performed directly.

[0076] Figure 4 Yes means Figure 2 The structure of the mobile terminal 202 is shown in FIG. Figure 4 1 and 2. The transmission processing of the mobile terminal 202 shown in FIG. 1 is described. First, the control data from the control unit 310 and the user data from the application unit 302 are sent to the protocol processing unit 301. The control data and the user data can be buffered. The buffering of the control data and the user data can be set in the control unit 310, the application unit 302, or the protocol processing unit 301. The protocol processing unit 301 performs protocol processing such as SDAP, PDCP, RLC, MAC, etc., for example, it performs actions such as determining the transmission target base station in DC, etc., and assigning headers in each protocol. The data that has undergone protocol processing is transmitted to the encoding unit 304, and coding processing such as error correction is performed. There may also be data that is directly output from the protocol processing unit 301 to the modulation unit 305 without performing coding processing. The data encoded by the encoding unit 304 is modulated in the modulation unit 305. Precoding in MIMO can also be performed in the modulation unit 305. After the modulated data is converted into a baseband signal, it is output to the frequency conversion unit 306 and converted into a wireless transmission frequency. After that, the transmission signal is transmitted from antennas 307-1 to 307-4 to base station 213. Figure 4 , the example shows a case where the number of antennas is 4, but the number of antennas is not limited to 4.

[0077] In addition, the receiving process of the mobile terminal 202 is performed as follows. The wireless signal from the base station 213 is received through the antennas 307-1 to 307-4. The received signal is converted from the wireless receiving frequency to a baseband signal by the frequency conversion unit 306, and demodulated in the demodulation unit 308. In the demodulation unit 308, waiting calculation and multiplication processing can be performed. The demodulated data is transmitted to the decoding unit 309, and decoding processing such as error correction is performed. The decoded data is transmitted to the protocol processing unit 301, and protocol processing such as MAC, RLC, PDCP, SDAP, etc., such as removal of headers in each protocol, etc., is performed. Among the data after protocol processing, control data is transmitted to the control unit 310, and user data is transmitted to the application unit 302.

[0078] A series of processes of the mobile terminal 202 are controlled by the control unit 310. Figure 4 Although omitted in FIG. 3 , the control unit 310 is also connected to each unit 302 and 304 to 309 .

[0079] Each part of the mobile terminal 202, such as the control unit 310, the protocol processing unit 301, the encoding unit 304, and the decoding unit 309, is implemented by a processing circuit including a processor and a memory. For example, the control unit 310 is implemented by the processor executing a program that describes a series of processes of the mobile terminal 202. The program that describes a series of processes of the mobile terminal 202 is stored in the memory. Examples of memories are non-volatile or volatile semiconductor memories such as RAM (Random Access Memory), ROM (Read Only Memory), and flash memory. Each part of the mobile terminal 202, such as the control unit 310, the protocol processing unit 301, the encoding unit 304, and the decoding unit 309 can be implemented by a dedicated processing circuit such as FPGA (Field Programmable Gate Array), ASIC (Application Specific Integrated Circuit), DSP (Digital Signal Processor). In Figure 4 In the present invention, the number of antennas used by the mobile terminal 202 for sending may be the same as or different from the number of antennas used for receiving.

[0080] Figure 5 Yes means Figure 2 The structure of the base station 213 is shown in FIG. Figure 5The sending process of the base station 213 shown is explained. The EPC communication unit 401 sends and receives data between the base station 213 and the EPC. The 5GC communication unit 412 sends and receives data between the base station 213 and the 5GC (5GC unit 214, etc.). The other base station communication units 402 send and receive data with other base stations. The EPC communication unit 401, the 5GC communication unit 412, and the other base station communication units 402 exchange information with the protocol processing unit 403 respectively. The control data from the control unit 411, and the user data and control data from the EPC communication unit 401, the 5GC communication unit 412, and the other base station communication units 402 are sent to the protocol processing unit 403. Buffering of control data and user data can be performed. The buffering of control data and user data can be set in the control unit 411, can be set in the EPC communication unit 401, can be set in the 5GC communication unit 412, and can also be set in the other base station communication units 402.

[0081] The protocol processing unit 403 performs protocol processing such as SDAP, PDCP, RLC, and MAC, for example, performs routing of transmission data in DC, assigning headers in each protocol, and other operations. The data that has undergone protocol processing is transmitted to the encoding unit 405, and coding processing such as error correction is performed. There may also be data that is directly output from the protocol processing unit 403 to the modulation unit 406 without performing coding processing. In addition, data can be sent from the protocol processing unit 403 to other base station communication units 402. For example, in DC, data sent from the 5GC communication unit 412 or the EPC communication unit 401 can be sent to other base stations, such as auxiliary base stations, via other base station communication units 402. The encoded data is modulated in the modulation unit 406. Precoding in MIMO can also be performed in the modulation unit 406. After the modulated data is converted into a baseband signal, it is output to the frequency conversion unit 407 and converted into a wireless transmission frequency. Thereafter, the transmission signal is sent to one or more mobile terminals 202 using antennas 408-1 to 408-4. In Figure 5 , the example shows a case where the number of antennas is 4, but the number of antennas is not limited to 4.

[0082] In addition, the receiving process of the base station 213 is performed as follows. The wireless signal from one or more mobile terminals 202 is received by the antennas 408-1 to 408-4. The received signal is converted from the wireless receiving frequency to a baseband signal by the frequency conversion unit 407, and demodulated in the demodulation unit 409. The demodulated data is transmitted to the decoding unit 410, and decoding processing such as error correction is performed. The decoded data is transmitted to the protocol processing unit 403, and protocol processing such as MAC, RLC, PDCP, SDAP, etc., such as the removal of headers in each protocol, etc., is performed. Among the data after the protocol processing, the control data is transmitted to the control unit 411 or the 5GC communication unit 412 or the EPC communication unit 401 or other base station communication units 402, and the user data is transmitted to the 5GC communication unit 412 or the EPC communication unit 401 or other base station communication units 402. Data sent from other base station communication units 402 can be sent to the 5GC communication unit 412 or the EPC communication unit 401. The data may be, for example, uplink data sent to the 5GC communication unit 412 or the EPC communication unit 401 via other base stations in DC.

[0083] A series of processing of the base station 213 is controlled by the control unit 411. Figure 5 Although omitted in the figure, the control unit 411 is also connected to each of the parts 401, 402, 405 to 410, and 412.

[0084] Each part of the base station 213, such as the control unit 411, the protocol processing unit 403, the 5GC communication unit 412, the EPC communication unit 401, the other base station communication unit 402, the encoding unit 405, and the decoding unit 410 are implemented by a processing circuit including a processor and a memory, or a dedicated processing circuit such as an FPGA, an ASIC, or a DSP, similar to the mobile terminal 202. Figure 5 In the present invention, the number of antennas used by the base station 213 for sending may be the same as or different from the number of antennas used for receiving.

[0085] As Figure 2 The example of the structure of CU 215 is shown, except that Figure 5 In addition to the coding unit 405, modulation unit 406, frequency conversion unit 407, antennas 408-1 to 408-4, demodulation unit 409, and decoding unit 410 shown, a configuration with a DU communication unit may also be used. The DU communication unit is connected to the protocol processing unit 403. The protocol processing unit 403 in the CU 215 performs protocol processing such as PDCP and SDAP.

[0086] As Figure 2 The example of the structure of DU 216 is shown, except Figure 5In addition to the EPC communication unit 401, other base station communication unit 402, and 5GC communication unit 412 shown, a configuration with a CU communication unit is sometimes used. The CU communication unit is connected to the protocol processing unit 403. The protocol processing unit 403 in the DU 216 performs protocol processing such as PHY, MAC, and RLC.

[0087] Figure 6 It is a block diagram showing the structure of the 5GC unit. Figure 6 The above Figure 2 The structure of the 5GC unit 214 is shown. Figure 6 Shown in Figure 2 The 5GC unit 214 shown includes the structure of AMF, the structure of SMF, and the structure of UPF. Figure 6 In the example shown, the AMF may have the function of a control layer control unit 525, the SMF may have the function of a session management unit 527, and the UPF may have the functions of a user layer communication unit 523 and a data network communication unit 521. The data network communication unit 521 performs data transmission and reception between the 5GC unit 214 and the data network. The base station communication unit 522 performs data transmission and reception between the 5GC unit 214 and the base station 213 via the NG interface. User data sent from the data network is transmitted from the data network communication unit 521 to the base station communication unit 522 via the user layer communication unit 523, and is sent to one or more base stations 213. User data sent from the base station 213 is transmitted from the base station communication unit 522 to the data network communication unit 521 via the user layer communication unit 523, and is sent to the data network.

[0088] The control data transmitted from the base station 213 is transmitted from the base station communication unit 522 to the control layer control unit 525. The control layer control unit 525 may transmit the control data to the session management unit 527. The control data may be transmitted from the data network. The control data transmitted from the data network may be transmitted from the data network communication unit 521 to the session management unit 527 via the user layer communication unit 523. The session management unit 527 may transmit the control data to the control layer control unit 525.

[0089] The user plane control unit 523 includes a PDU processing unit 523-1, a mobile anchor unit 523-2, etc., and performs overall processing for the user plane (hereinafter sometimes referred to as U-Plane). The PDU processing unit 523-1 processes data packets, such as the transmission and reception of packets between the data network communication unit 521 and the transmission and reception of packets between the base station communication unit 522. The mobile anchor unit 523-2 is responsible for the connection of the data path when the UE moves.

[0090] The session management unit 527 manages the PDU session set between the UE and the UPF. The session management unit 527 includes a PDU session control unit 527-1, a UE IP address allocation unit 527-2, etc. The PDU session control unit 527-1 manages the PDU session between the mobile terminal 202 and the 5GC unit 214. The UE IP address allocation unit 527-2 allocates an IP address to the mobile terminal 202, etc.

[0091] The control layer control unit 525 includes a NAS security unit 525-1, an idle state mobility management unit 525-2, etc., and performs overall processing for the control layer (hereinafter, sometimes also referred to as C-Plane). The NAS security unit 525-1 performs security protection for NAS (Non-Access Stratum) messages, etc. The idle state mobility management unit 525-2 performs mobility management in the idle state (idle state: RRC_IDLE state, or simply called idle), generation and control of paging signals in the idle state, addition, deletion, update, retrieval, and tracking area list management of one or more mobile terminals 202 under coverage, etc.

[0092] A series of processing of the 5GC unit 214 is controlled by the control unit 526. Figure 6 Although omitted in the figure, the control unit 526 is connected to each unit 521 to 523, 525, and 527. Each part of the 5GC unit 214 is similar to the control unit 310 of the mobile terminal 202, and is implemented by, for example, a processing circuit including a processor and a memory, or a dedicated processing circuit such as an FPGA, ASIC, or DSP.

[0093] Next, an example of a cell search method in a communication system is shown. Figure 7 This is a flowchart showing an overview of the cell search and standby operation performed by a communication terminal (UE) in a communication system of the NR mode. If the communication terminal starts the cell search, in step ST601, the first synchronization signal (P-SS) and the second synchronization signal (S-SS) sent from the surrounding base stations are used to synchronize the time slot timing and the frame timing.

[0094] P-SS and S-SS are collectively referred to as synchronization signals (SS). The synchronization signal (SS) is assigned a synchronization code that corresponds to the PCI (Physical Cell Identifier) ​​assigned to each cell. The number of PCIs is set to 1008. The communication terminal uses the 1008 PCIs to achieve synchronization and detects (determines) the PCI of the synchronized cell.

[0095] In step ST602, the communication terminal receives the PBCH for the next cell to acquire synchronization. The MIB (Master Information Block) containing the cell structure information is mapped to the BCCH on the PBCH. Therefore, by receiving the PBCH and obtaining the BCCH, the MIB can be obtained. The MIB information includes, for example, SFN (System Frame Number), scheduling information of SIB (System Information Block) 1, subcarrier spacing of SIB1, etc., information on DM-RS positions, etc.

[0096] In addition, the communication terminal obtains the SS block identifier through the PBCH. A portion of the bit column of the SS block identifier is included in the MIB. The remaining bit column is included in the identifier of the sequence used to generate the DM-RS attached to the PBCH. The communication terminal uses the MIB included in the PBCH and the sequence of the DM-RS attached to the PBCH to obtain the SS block identifier.

[0097] Next, in step ST603, the communication terminal measures the reception power of the SS block.

[0098] Next, in step ST604, the communication terminal selects a cell with the best reception quality from the one or more cells detected up to step ST603, for example, a cell with the highest reception power, i.e., the best cell. In addition, the communication terminal selects a beam with the best reception quality, for example, a beam with the highest reception power of an SS block, i.e., the best beam. The best beam is selected, for example, using the reception power of the SS block identified by each SS block.

[0099] Next, in step ST605, the communication terminal receives DL-SCH based on the scheduling information of SIB1 included in the MIB, and obtains SIB (System Information Block) 1 in the broadcast information BCCH. SIB1 includes information related to access to the cell, cell structure information, and scheduling information of other SIBs (SIBk: an integer of k ≥ 2). In addition, SIB1 also includes a tracking area code (Tracking Area Code: TAC).

[0100] Then in step ST606, the communication terminal compares the TAC of SIB1 received in step ST605 with the TAC part of the tracking area identity (TAI) in the tracking area list already held by the communication terminal. The tracking area list is also called the TAI list. TAI is identification information used to identify the tracking area, and is composed of MCC (Mobile Country Code), MNC (Mobile Network Code), and TAC (Tracking Area Code). MCC is the country code. MNC is the network code. TAC is the code number of the tracking area.

[0101] If the result of the comparison in step ST606 is that the TAC received in step ST605 is the same as the TAC included in the tracking area list, the communication terminal enters the standby action in the cell. If the TAC received in step ST605 is not included in the tracking area list, the communication terminal passes through the cell and requests the core network (CoreNetwork, EPC) including MME, etc. to change the tracking area to perform TAU (Tracking Area Update).

[0102] The device constituting the core network (hereinafter sometimes referred to as the "core network side device") updates the tracking area list based on the TAU request signal and the identification number (UE-ID, etc.) of the communication terminal sent from the communication terminal. The core network side device sends the updated tracking area list to the communication terminal. The communication terminal rewrites (updates) the TAC list held by the communication terminal based on the received tracking area list. Thereafter, the communication terminal enters standby action in the cell.

[0103] Next, an example of a random access method in a communication system is shown. In random access, 4-step random access and 2-step random access are used. In addition, for 4-step random access and 2-step random access, there are contention-based random access, that is, random access that may cause timing contention with other mobile terminals, and contention-free random access.

[0104] An example of a contention-based 4-step random access method is shown. As step 1, the mobile terminal sends a random access preamble to the base station. The random access preamble may be selected by the mobile terminal from a predetermined range, or may be individually allocated to the mobile terminal and notified by the base station.

[0105] As step 2, the base station sends a random access response to the mobile terminal. The random access response includes the uplink scheduling information used in step 3, the terminal identity used in the uplink transmission in step 3, and the like.

[0106] As step 3, the mobile terminal performs uplink transmission to the base station. The mobile terminal uses the information obtained in step 2 in uplink transmission. As step 4, the base station notifies the mobile terminal whether there is contention resolution. The mobile terminal notified of no conflict ends the random access process. The mobile terminal notified of a conflict starts the process again from step 1.

[0107] The contention-free 4-step random access method is different from the contention-based 4-step random access method in the following points: That is, the base station pre-allocates a random access preamble and uplink scheduling to the mobile terminal before step 1. In addition, the notification of whether or not a contention is resolved in step 4 is not required.

[0108] An example of a conflict-based 2-step random access method is shown. As step 1, the mobile terminal transmits a random access preamble and an uplink transmission to the base station. As step 2, the base station notifies the mobile terminal whether there is a conflict. The mobile terminal notified of no conflict ends the random access process. The mobile terminal notified of a conflict starts the process again from step 1.

[0109] The contention-free 2-step random access method is different from the contention-based 2-step random access method in the following respects: That is, before step 1, the base station pre-allocates a random access preamble and uplink scheduling to the mobile terminal. In addition, in step 2, the base station sends a random access response to the mobile terminal.

[0110] Figure 8 This shows an example of the structure of a cell in NR. In a cell in NR, a narrow beam is formed and its direction is changed for transmission. Figure 8 In the example shown, the base station 750 uses beam 751-1 at a certain time to transmit and receive with the mobile terminal. At other times, the base station 750 uses beam 751-2 to transmit and receive with the mobile terminal. Similarly, the base station 750 uses one or more of beams 751-3 to 751-8 to transmit and receive with the mobile terminal. Thus, the base station 750 forms a wide range of cells 752.

[0111] exist Figure 8 In FIG. 1 , an example is shown in which the number of beams used by the base station 750 is set to 8, but the number of beams may be different from 8. Figure 8 In the example shown, the number of beams used simultaneously by the base station 750 is set to one, but it can also be multiple.

[0112] The identification of beams uses the concept of QCL (Quasi-CoLocation) (refer to non-patent document 14 (3GPP TS 38.214)). That is, the beam is identified by information indicating which reference signal (e.g., SS block, CSI-RS) the beam can be considered to be the same as. This information sometimes includes the type of information about the viewpoints that can be considered to be the same beam, such as information about Doppler shift, Doppler shift spread, average delay, average delay spread, and spatial Rx parameters (refer to non-patent document 14 (3GPP TS38.214)).

[0113] In 3GPP, D2D (Device to Device) communication and V2V (Vehicle to Vehicle) communication support side links (SL) (see Non-Patent Documents 1 and 16). SL is defined by the PC5 interface.

[0114] In SL communication, in addition to broadcast, in order to support unicast and groupcast, the support of PC5-S signaling is studied (refer to non-patent document 27 (3GPP TS 23.287)). For example, PC5-S signaling is implemented to establish SL, that is, a link for implementing PC5 communication. This link is implemented in the V2X layer and is also called a layer 2 link.

[0115] In addition, in SL communication, support for RRC signaling is being studied (see non-patent document 27 (3GPP TS23.287)). RRC signaling in SL communication is also called PC5 RRC signaling. For example, it is proposed to notify the capabilities of UEs between UEs performing PC5 communication, or to notify the settings of the AS layer for V2X communication using PC5 communication.

[0116] Fig. 9 An example of the connection structure of a mobile terminal in SL communication is shown in FIG. Fig. 9 In the example shown, UE 805 and UE 806 exist within the coverage area 803 of base station 801. UL / DL communication 807 is performed between base station 801 and UE 805. UL / DL communication 808 is performed between base station 801 and UE 806. SL communication 810 is performed between UE 805 and UE 806. UE 811 and UE 812 exist outside the coverage area 803. SL communication 814 is performed between UE 805 and UE 811. In addition, SL communication 816 is performed between UE 811 and UE 812.

[0117] As an example of communication between UE and NW via relay in SL communication, Fig. 9 UE 805 is shown relaying communications between UE 811 and base station 801 .

[0118] A UE that performs relaying sometimes uses Figure 4 Same structure. Use Figure 4 The relay processing in the UE is described. The relay processing of UE 805 in the communication from UE 811 to base station 801 is described. The wireless signal from UE 811 is received through antennas 307-1 to 307-4. The received signal is converted from the wireless reception frequency to a baseband signal by the frequency conversion unit 306, and demodulated in the demodulation unit 308. In the demodulation unit 308, waiting calculation and multiplication processing can be performed. The demodulated data is transmitted to the decoding unit 309, and decoding processing such as error correction is performed. The decoded data is transmitted to the protocol processing unit 301, and protocol processing such as MAC, RLC, etc. for communication with UE 811, such as removal of headers in each protocol, etc. is performed. In addition, protocol processing such as RLC, MAC, etc. for communication with base station 801, such as the addition of headers in each protocol, etc. is performed. In the protocol processing unit 301 of UE 811, protocol processing of PDCP and SDAP is sometimes performed. The data that has been processed by the protocol is transmitted to the coding unit 304, and coding processing such as error correction is performed. There may also be data that is directly output from the protocol processing unit 301 to the modulation unit 305 without being subjected to coding processing. The data that has been coded by the coding unit 304 is modulated in the modulation unit 305. Precoding in MIMO may also be performed in the modulation unit 305. After the modulated data is converted into a baseband signal, it is output to the frequency conversion unit 306 and converted into a wireless transmission frequency. Thereafter, the transmission signal is transmitted from the antennas 307-1 to 307-4 to the base station 801.

[0119] In the above content, an example of relaying of UE 805 in communication from UE 811 to base station 801 is shown, but the same processing is also used in relaying of communication from base station 801 to UE 811.

[0120] 5G base stations can support integrated access and backhaul (IAB) (see non-patent literature 2, 20). A base station that supports IAB (hereinafter sometimes referred to as an IAB base station) is composed of a CU of a base station that acts as an IAB host providing IAB functions, namely, an IAB host CU, a DU of a base station that acts as an IAB host, namely, an IAB host DU, and an IAB node that uses a wireless interface to connect to the IAB host DU and to the UE. An F1 interface is set between the IAB node and the IAB host CU (see non-patent literature 2).

[0121] Fig.10 An example of the connection of an IAB base station is shown in FIG. An IAB host CU 901 is connected to an IAB host DU 902. An IAB node 903 is connected to an IAB host DU 902 using a wireless interface. An IAB node 903 is connected to an IAB node 904 using a wireless interface. That is, multi-level connections of IAB nodes are sometimes made. A UE 905 is connected to an IAB node 904 using a wireless interface. A UE 906 is sometimes connected to an IAB node 903 using a wireless interface, and a UE 907 is sometimes connected to an IAB host 902 using a wireless interface. Multiple IAB host DUs 902 can be connected to an IAB host CU 901, multiple IAB nodes 903 can be connected to an IAB host DU 902, and multiple IAB nodes 904 can be connected to an IAB node 903.

[0122] In the connection between the IAB host DU and the IAB node and the connection between the IAB nodes, a BAP (Backhaul Adaptation Protocol) layer is set (see non-patent document 29). The BAP layer performs operations such as routing received data to the IAB host DU and / or IAB node, mapping to the RLC channel, etc. (see non-patent document 29).

[0123] As an example of the structure of the IAB host CU, the same structure as that of the CU 215 is used.

[0124] As an example of the structure of the IAB host DU, the same structure as that of DU 216 is used. In the protocol processing unit of the IAB host DU, BAP layer processing is performed, such as the addition of a BAP header in downlink data, routing to an IAB node, and removal of a BAP header in uplink data.

[0125] As an example of the structure of an IAB node, sometimes in addition to Figure 5 The structure other than the EPC communication unit 401, other base station communication unit 402, and 5GC communication unit 412 shown.

[0126] use Figure 5 , Fig.10 To illustrate the transceiver processing in the IAB node. The transceiver processing of the IAB node 903 in the communication between the IAB host CU 901 and the UE 905 is explained. In the uplink communication from the UE 905 to the IAB host CU 901, the wireless signal from the IAB node 904 is received through the antenna 408 (part or all of the antennas 408-1 to 408-4). The received signal is converted from the wireless reception frequency to a baseband signal by the frequency conversion unit 407, and demodulated in the demodulation unit 409. The demodulated data is transmitted to the decoding unit 410, and decoding processing such as error correction is performed. The decoded data is transmitted to the protocol processing unit 403, and protocol processing such as MAC, RLC, etc. for communication with the IAB node 904, such as removal of headers in each protocol, etc., is performed. In addition, routing to the IAB host DU 902 using the BAP header is performed, and protocol processing such as RLC, MAC, etc. for communication with the IAB host DU 902, such as the assignment of headers in each protocol, is performed. The data that has undergone protocol processing is transmitted to the encoding unit 405, and coding processing such as error correction is performed. There may also be data that is directly output from the protocol processing unit 403 to the modulation unit 406 without performing coding processing. The encoded data is modulated in the modulation unit 406. Precoding in MIMO may also be performed in the modulation unit 406. After the modulated data is converted into a baseband signal, it is output to the frequency conversion unit 407 and converted into a wireless transmission frequency. Thereafter, the transmission signal is sent to the IAB host DU 902 using antennas 408-1 to 408-4. The same processing is also performed in the downlink communication from the IAB host CU 901 to the UE 905.

[0127] The IAB node 904 also performs the same transmission and reception processing as the IAB node 903. In the protocol processing unit 403 of the IAB node 903, as BAP layer processing, for example, the addition of a BAP header in uplink communication and routing to the IAB node 904, and the removal of a BAP header in downlink communication are performed.

[0128] A repeater can be used in the communication between the base station and the UE (hereinafter sometimes referred to as an access link (AL) (see non-patent document 31)). A repeater can have multiple beams. A repeater can receive a signal from a transmission source, amplify it, and send the amplified signal to a transmission destination (this action is sometimes referred to as AL transmission and reception). A repeater can use beams in AL transmission and reception.

[0129] The base station can control the repeater. The base station can send a control signal to the repeater (a link used to send a control signal from the base station to the repeater is sometimes called a fronthaul link (FL) (see Non-Patent Document 31)). The control signal can use L1 / L2 signaling.

[0130] The base station can control the beam used by the repeater. The control performed by the base station can be, for example, switching of the beam. For example, the base station can switch the beam based on the movement of the UE. The control performed by the base station can use measurement. The measurement can be L1 measurement or L3 measurement. The UE can notify the base station of the measurement result. In addition, L1 measurement (L1 measurement) is a measurement method in which the measurement result is included in the UCI for reporting (refer to non-patent document 12 (3GPP TS38.212)), and L3 measurement (L3 measurement) is a measurement method in which the measurement result is included in the RRC message for reporting (refer to non-patent document 2 (3GPP TS38.300)).

[0131] However, the above-mentioned prior arts do not disclose the object and process of measurement when the UE is connected to the base station via a repeater. Therefore, the following problems arise: the UE cannot perform measurement, and the base station cannot control the beam of the repeater, resulting in the UE being unable to connect to the base station via the repeater.

[0132] In the first embodiment, a method for solving such a problem is disclosed.

[0133] In this method, the base station sends a signal used in the measurement. The base station can send the signal in the AL. The signal can be, for example, a CSI-RS or an SS block. The repeater receives the signal and sends the received signal to the UE. The repeater can perform an amplification operation when sending the signal. The base station can send the signal together with other signals / channels, such as UE layer data to the UE. The repeater can perform an amplification operation when sending the above-mentioned other signals / channels. The repeater can make the amplification factor of the measurement signal the same as or different from the amplification factor of other signals / channels.

[0134] The repeater may perform beamforming processing when sending a measurement signal to the UE, and may also perform beamforming processing when sending other signals / channels to the UE.

[0135] Fig.11 It is a diagram showing a measurement signal transmitted from a base station. Fig.11 In the example, the base station 1101 sends a measurement signal 1107 to the repeater 1102 . Fig.11In the example shown, CSI-RS is used as the measurement signal 1107. The base station 1101 may transmit the measurement signal 1107 together with the PDSCH 1105. The repeater 1102 receives the measurement signal 1107 and the PDSCH 1105 from the base station 1101, and transmits them to the UE 1103. The repeater 1102 may amplify the measurement signal 1107 and the PDSCH 1105 received from the base station 1101, and transmits them to the UE 1103. In the transmission of the above-mentioned signals from the relay 1102 to the UE 1103, beamforming processing may be performed. The UE 1103 receives the measurement signal 1107 and performs measurement. The UE 1103 may obtain U-layer data through the PDSCH 1105.

[0136] Fig.11 1107, an example of using CSI-RS as the measurement signal 1107 is shown, but an SS block may also be used. Thus, for example, when UE 1103 is connected to another base station, the UE 1103 can perform measurement of the SS block transmitted via the relay 1102, and as a result, the UE 1103 can be connected to the base station 1101 via the relay 1102. Hereinafter, the description will be continued by omitting the reference numerals of the base station 1101, the relay 1102, and the UE 1103.

[0137] The base station can indicate the transmission and reception between the relay and the UE. The indication can be performed using FL, for example. The indication can use L1 / L2 signaling, for example. A new DCI can be set. The indication can use a new DCI. Thus, for example, it can prevent other UEs from receiving DCI for the relay and causing malfunction. As another example, the indication can use MAC signaling. Thus, for example, the base station can send more information to the relay. As another example, the indication can use RRC signaling. Thus, for example, the base station can send more information to the relay.

[0138] As examples of information included in the instruction, the following (1) to (14) are disclosed.

[0139] (1) Information identifying the transmitting device and / or receiving device in AL transmission and reception.

[0140] (2) Information related to the connection between the transmitting device and the receiving device in AL transmission and reception.

[0141] (3) Information related to time resources.

[0142] (4) Information related to frequency resources.

[0143] (5) Information related to the beam used in AL transmission and reception.

[0144] (6) Information related to the transmitting and receiving angles.

[0145] (7) Information related to the gain of the repeater's transmission and reception.

[0146] (8) Information related to the transmission power of the repeater.

[0147] (9) Information related to the ON / OFF of the AL transmission and reception operation of the repeater.

[0148] (10) Information about the direction of the link received and sent by the repeater's AL.

[0149] (11) Information related to the signals / channels sent and received by the repeater.

[0150] (12) Information related to default actions.

[0151] (13) Information related to transmission in repeaters, etc.

[0152] (14) A combination of the above (1) to (13).

[0153] The information in (1) above may include an identifier of the UE. The identifier of the UE may include, for example, a C-RNTI (Cell Radio Network Temporary Identifier). Thus, for example, the repeater can quickly identify the UE that is the object of AL transmission and reception. As other examples, the information may include an identifier of a base station, an identifier of a DU, an identifier of a TRP, an identifier of a cell, or an identifier of an IAB node. Thus, for example, the repeater can quickly identify the base station, DU and / or IAB node that are the objects of AL transmission and reception.

[0154] The information in (2) above may include, for example, information about the PDU session used by the UE. The repeater can use this information to identify the source device and the destination device. This can reduce the size of signaling from the base station to the repeater, for example.

[0155] The information in (3) above may include information about the time when AL transmission and reception starts, information about the duration of AL transmission and reception, or information about the time when AL transmission and reception ends. The information may include any one or more combinations of wireless frame numbers, subframe numbers, time slot numbers, and symbol numbers. As another example, the information in (3) above may include information about the time from the indication to the start of AL transmission and reception. The information may include any one or more combinations of wireless frame numbers, subframe numbers, time slot numbers, and symbol numbers. As another example, the information in (3) above may include information about the time slot length, or information about the subcarrier spacing (SCS). The repeater may use the information to obtain information about the timing of AL transmission and reception. The repeater may perform AL transmission and reception in the time resources included in the information in (3). The repeater may stop AL transmission and reception outside the time resources included in the information in (3), or perform default AL transmission and reception. Thus, for example, the repeater can perform AL transmission and reception at an appropriate timing and reduce the power consumption of the repeater.

[0156] The information in (4) may include information about the lower end of the frequency resource (e.g., subcarrier) for AL transceiver, or may include information about the upper end of the frequency resource. The information in (4) may include information about the frequency, information about the subcarrier number, or information about the physical resource block (PRB). The information in (4) may include information about the range of the frequency resource. The information about the range may include information about the frequency width, information about the number of subcarriers, or information about the number of PRBs. The information in (4) may include information about the frequency band including the frequency resource. The information about the frequency band may include information about the frequency band of the carrier, or information about the BWP. The repeater may use the information to obtain information about the frequency used in AL transceiver. The repeater may perform transceiver operations related to AL transceiver in the frequency resource included in the information in (4). The repeater may not perform transceiver operations related to AL transceiver outside the frequency resource included in the information in (4). For example, the repeater can perform AL transmission and reception within an appropriate frequency range, and the power consumption of the repeater can be reduced.

[0157] The information in (5) above may include information about the beam used by the base station, DU, TRP and / or IAB node (hereinafter, sometimes collectively referred to as the base station, etc.), may include information about the beam used by the repeater in transceiving with the base station, etc., and may also include information about the beam used by the repeater in transceiving with the UE. As another example, the information in (5) above may include information about the beam used by the repeater for receiving actions, and may also include information about the beam used by the repeater for sending actions. The information about the above beam may include an identifier of an SS block, and may also include an identifier of a CSI-RS. The above identifier may, for example, be an identifier of an SS block and / or CSI-RS included in a beam having a QCL relationship with the beam received by the repeater. The information in (5) above may include information about the RS sent by the repeater. The information about the RS may, for example, include information about the setting of the CSI-RS sent by the repeater, and may also include information about the setting of the SS block sent by the repeater. The repeater may use this information to direct the beam toward a device that is the object of AL transceiver. As a result, for example, communication via a repeater becomes possible between a base station or the like and a UE.

[0158] The information in (5) above may include information about the beam width. The repeater may use this information to determine the beam width. For example, a narrow beam may be used in transmission from the repeater to the base station, and a wide beam may be used in transmission from the repeater to a frequently moving UE. Thus, for example, reliable communication may be performed with lower power consumption.

[0159] The information in (6) above may include information related to the receiving angle in the repeater, and may also include information related to the transmitting angle in the repeater. The information about the above angle may include, for example, information related to the azimuth angle, and may also include information related to the elevation angle. The information about the above angle may be given as an angle based on a specified direction. The specified direction may be an absolute direction, such as the horizontal north direction, or a relative direction, such as the direction from the repeater toward the base station. The repeater can use this information to perform the receiving and transmitting operations involved in AL transmission and reception. The repeater may also not receive radio waves from outside the receiving angle included in the information in (6) above. As a result, for example, the performance of transmission and reception via the repeater (for example, SINR (Signal to Interference Noise Ratio)) can be improved.

[0160] The above-mentioned (6) information may include information related to the reflected wave emission angle in the repeater. For example, this information may be included when a reflector is used instead of a repeater, or when a reconfigurable intelligent surface (RIS) is used. Thus, for example, power consumption in the communication system can be reduced, and the coverage of the base station can be expanded.

[0161] The information in (7) above may include information related to the receiving gain in the repeater, information related to the transmitting gain in the repeater, and information related to the gain from the receiving end to the transmitting end in the repeater. The repeater may use this information to perform amplification in AL transceiver. Thus, for example, the repeater may perform AL transceiver using sufficient power required for AL transceiver between the base station and the UE, thereby reducing interference to other base stations and / or UEs.

[0162] The above-mentioned (7) information may include information about the attenuation in the repeater. The information about the attenuation may include information about the attenuation in the receiving unit, information about the attenuation in the transmitting unit, or information about the attenuation from the transmitting end to the receiving end. Thus, for example, when the power used in AL transmission and reception is large, the power can be reduced, and as a result, the interference with the devices of the surrounding communication system can be reduced. In addition, even when a non-amplifying repeater such as a reflector or RIS is used, the power involved in AL transmission and reception can be controlled.

[0163] The relay can use the information related to (8) above to send a signal to the base station and / or UE. This enables, for example, transmission and reception between the base station and the UE, and reduces interference to other base stations and / or UE.

[0164] The repeater can use the information in (9) above to start or stop the AL transmission and reception operation. This can, for example, reduce power consumption in the repeater.

[0165] The information in (10) above may include, for example, information related to the uplink, information related to the downlink, and information related to the sidelink. The repeater may use this information to determine the receiving target and / or the sending target in AL transmission and reception. Thus, for example, the amount of signaling from the base station to the repeater can be reduced.

[0166] The information in (11) above may include, for example, information indicating that it is a signal / channel sent to the UE individually, or information indicating that it is a signal / channel sent to the UE together. The information in (11) above may include information indicating that it is data (for example, U layer data), information indicating that it is a control signal, or information indicating that it is a reference signal. The information in (11) above may include, for example, information for identifying a signal / channel (for example, PDCCH, PUSCH, SS block). The repeater may use this information to perform AL transceiver operations. Thus, for example, complexity in the control of the repeater can be avoided.

[0167] The information in (11) may include information related to the repetition of the signal / channel. The information may include, for example, information related to the number of repetitions. The repeater may use the information to perform multiple AL transmissions and receptions. Thus, for example, the signal / channel passing through the repeater may be repeated in the communication system.

[0168] The information in (12) above may include, for example, information related to the AL transceiver operation of the repeater when there is no instruction from the base station. The information may be, for example, information indicating that the AL transceiver of the repeater is set to OFF, information indicating that the repeater uses a specified beam to perform a receiving operation, or information indicating that the repeater uses a specified beam to perform a transmitting operation. The repeater may use this information to perform a default AL transceiver operation. Thus, for example, the amount of signaling involved in AL transceiver operation may be reduced.

[0169] The information in (13) may include, for example, information on transmittance relative to incident power, information on transmitted power, information on reflectance relative to incident power, or information on reflected power. This information may be used, for example, in a reflector and / or RIS. A repeater or other device may use this information to control the device. Thus, for example, when the control of the attenuation is complex, the complexity of the control of the reflected power can be avoided.

[0170] The information (1) to (14) above may be set for each UE or for each signal / channel. For example, the beam used in the transmission of the SS block may be different from the beam used in the transmission of the PDCCH and / or PDSCH. Thus, for example, power efficiency can be ensured and coverage can be improved in the communication system.

[0171] The measurement may be, for example, L1 measurement (refer to non-patent literature 14, 32 (3GPP TS38.215)). The measurement object in the L1 measurement of the UE may be, for example, RSRP, RSRQ and / or SINR of CSI, RSRP, RSRQ and / or SINR of SS blocks, or a combination of the above. The base station may notify the UE of information related to the measurement object. The UE may use the information obtained in the notification to perform L1 measurement.

[0172] The measurement object may include received signal strength. The notification from the base station to the UE may include information related to the received signal strength. Thus, for example, the UE can quickly perform the measurement.

[0173] The UE can provide CSI feedback to the base station. CSI feedback can be performed using the results of the above-mentioned L1 measurement. CSI feedback may include, for example, CQI, PMI, RI, CSI-RS resource indicator (CSI-RSResource Indicator: CRI), SS block resource indicator (SS / PBCH Resource Indicator: SSBRI), layer indicator (Layer Indicator: LI), L1-RSRP, L1-SINR, or multiple of the above. CRI and / or SSBRI may be notified from the base station, for example, CRI and / or SSBRI measured by indication from the base station.

[0174] The CSI feedback notified from the UE to the base station may not include the PMI. For example, when the relay does not perform precoding, the CSI feedback sent by the UE may not include the PMI. This can reduce the size of the CSI feedback from the UE, for example.

[0175] The base station may indicate to the UE the information included in the CSI feedback. The indication may be performed using RRC signaling.

[0176] The base station can use the information obtained from the CSI feedback to perform beam control in the base station, perform transmit power control, instruct the repeater to perform beam control, or instruct the repeater to perform transmit power.

[0177] The base station may notify the UE of the setting of the CSI-RS. The notification from the base station to the UE may be performed via a relay. The notification may use RRC signaling, for example. The notification may include information related to the time / frequency resources of the CSI-RS, and may also include information related to the identification of the CSI-RS. The UE may use the notification to receive the CSI-RS and may also provide CSI feedback.

[0178] The configuration of the CSI-RS of the UE and / or the notification of information included in the CSI feedback from the base station may be related to multiple CSI-RS. The base station may configure the UE with respect to multiple CSI-RS and may configure CSI feedback with respect to multiple CSI-RS. Thus, for example, the UE can perform measurements related to multiple beams sent from a repeater.

[0179] Fig.12 is a diagram showing an example of an action sequence of L1 measurement of a UE connected to a base station via a relay. Fig.12 An example of using CSI-RS in L1 measurement is shown. Fig.12 An example is shown in which a base station transmits a CSI-RS and a UE receives it. Fig.12 In the figure, the arrow with a black circle indicates that the signal transmission and reception between the base station and the UE is carried out via the repeater.

[0180] exist Fig.12 In step ST1205 shown, the base station instructs the repeater to set the beam. The instruction may include information related to the beam used by the repeater, may include information indicating the transmission and reception of downlink signals, may include information related to the time / frequency resources for the transmission and reception of the repeater, and may include information related to the UE. Step ST1205 may be performed using side control information (Side Control Information) (refer to non-patent document 30). Step ST1205 may be, for example, L1 / L2 signaling from the base station to the repeater. The repeater uses the information received in step ST1205 to control the beam involved in the transmission from the base station to the UE, etc. In step ST1207, the base station sends a CSI-RS to the repeater, and the repeater receives the CSI-RS and sends it to the UE. The repeater can perform power control, such as amplification, of the CSI-RS. In step ST1210, the UE measures the CSI-RS sent from the base station via the repeater.

[0181] exist Fig.12 In step ST1215 shown, the base station instructs the relay to set the beam. This instruction can use the same signaling as step ST1205. In step ST1217, the base station sends an uplink grant for the UE to the relay, and the relay receives the uplink grant and sends it to the UE.

[0182] exist Fig.12In step ST1221 shown, the base station instructs the repeater to set the beam. The instruction may include information indicating that the uplink signal is being sent and received. The instruction may use the same signaling as step ST1205. In step ST1223, the UE sends CSI feedback to the repeater, and the repeater receives the CSI feedback and sends it to the UE. The CSI feedback may include the measurement result in step ST1210.

[0183] exist Fig.12 Before step ST1205 shown, the CSI-RS may be configured for the UE from the base station. The configuration may be performed using RRC signaling, for example. The configuration may be performed via a relay. Thus, for example, the UE can quickly grasp the CSI-RS to be received.

[0184] As another example of this measurement, it can be L3 measurement (refer to non-patent document 19). The base station can notify the UE of information related to the measured signal, and can also notify the UE of information related to the measurement report. The signal of the UE's measurement object can be a signal sent via a repeater. The UE can use this information to perform L3 measurement. The UE can notify the base station of the measurement result. For example, the base station can use the notified measurement result to decide on the switching of the UE. As a result, for example, the UE can switch to another base station via a repeater.

[0185] Fig.13 is a diagram showing an example of an action sequence of L3 measurement of a UE connected to a base station via a relay. Fig.13 An example of using CSI-RS in L3 measurement is shown. Fig.13 An example is shown in which a base station transmits a CSI-RS and a UE receives it. Fig.13 In the figure, the arrow with a black circle indicates that the signal transmission and reception between the base station and the UE is carried out via the repeater. Fig.13 In, with Fig.12 The same step numbers are assigned to the same processes, and common descriptions are omitted.

[0186] exist Fig.13 In step ST1302 shown in FIG. 1 , the base station instructs the repeater to set the beam. This instruction can be used in conjunction with Fig.12 In step ST1304, the base station sends the measurement for the UE to the relay, and the relay receives the measurement setting and sends it to the UE. Step ST1304 may use RRC signaling, such as RRC reconfiguration.

[0187] Fig.13 Steps ST1205, ST1207 and Fig.12 same.

[0188] Fig.13 Steps ST1308 and ST1309 shown are the same as steps ST1205 and ST1207, respectively.

[0189] Fig.13 Steps ST1210 to ST1217 shown are Fig.12 same.

[0190] exist Fig.13 In step ST1321 shown, the base station instructs the repeater to set the beam. The instruction may include information indicating that the uplink signal is being sent and received. The instruction may use the same signaling as step ST1205. In step ST1323, the UE sends a measurement report to the repeater, and the repeater receives the measurement report and sends it to the base station. Step ST1323 may use RRC signaling, such as a measurement report (MeasurementReport).

[0191] Fig.13 In FIG. 1 , it is shown that CSI-RS is used as Fig.11 The example of the measurement signal 1107 shown in FIG. 1 is an example of a measurement signal 1107, but an SS block may also be used. Thus, for example, even for a UE connected to the base station via a repeater, the SS block can be measured.

[0192] The following problem occurs in the measurement of the measurement signal via the repeater. That is, when the reception quality in the UE is poor, it is impossible to determine whether the radio wave environment between the base station and the repeater is poor or the radio wave environment between the repeater and the UE is poor. As an example of poor reception quality, consider the case where the received power in the UE is low. The base station uses the measurement results notified from the UE to increase the transmission power. As a result, for example, even when the attenuation between the base station and the repeater is small and the attenuation between the repeater and the UE is large, the result of increasing the transmission power from the base station is that the power between the base station and the repeater may become too large, causing interference to other communication devices.

[0193] As a solution to the above problem, the base station sets the transmission power for the repeater. This setting can be performed using FL, for example. This setting can use RRC signaling, MAC signaling, or L1 / L2 signaling. The repeater can also send the set power together with other signals / channels to the UE. The UE notifies the base station of the reception result of the signal from the repeater. As a result, for example, the base station can grasp the attenuation between the repeater and the UE.

[0194] As another solution to the above problem, the repeater can detect the signal sent from the base station.

[0195] The base station may instruct the repeater to measure the measurement signal. The instruction may be performed, for example, using FL. The instruction may be sent, for example, using side control information. The instruction may use L1 / L2 signaling. Thus, for example, rapid signaling from the base station to the repeater is possible. As another example, the instruction may use MAC signaling. Thus, for example, more information can be notified from the base station to the repeater. As another example, the instruction may use RRC signaling, such as RRC reconfiguration. Thus, for example, more information can be notified from the base station to the repeater.

[0196] The indication may include, for example, information identifying the measured measurement signal. The identifier may be, for example, an identifier of a CSI-RS or an identifier of an SS block. The indication may include information related to the resource of the measured measurement signal. The information about the resource may include, for example, information related to the PRB to which the measurement signal is allocated, information related to the code element, information related to the RE (Resource Element), information related to the period, and information related to the antenna port. The indication may include information related to the UE involved in the measurement, such as the identifier of the UE.

[0197] The measurements made by the repeater may be, for example, L1 measurements.

[0198] The relay may provide CSI feedback to the base station. The CSI feedback from the relay to the base station may include the measurement result obtained by the relay.

[0199] The base station can control the base station, for example, control the transmission power, using the measurement results notified from the repeater.

[0200] The measurement of the repeater and the measurement of the UE can be performed together. The repeater and the UE can notify the base station of the measurement results together. The base station can use the measurement results notified from the repeater and / or the measurement results notified from the UE to control the base station or the repeater. As a result, for example, the base station can perform appropriate control to a propagation path with a poor radio wave environment.

[0201] The measurement signal measured by the repeater may be, for example, the same signal as the measurement signal measured by the UE. The repeater may measure the measurement signal and transmit it to the UE at the same time. Thus, for example, the signal used in the measurement can be reduced, resulting in improved efficiency in the communication system.

[0202] The repeater may have the function of allocating and / or duplicating the received signal. The number of allocations and / or duplications may be 2 or more. The repeater may use one or more of the allocated or duplicated received signals for measurement, and may use the remaining one or more for transmission to the UE. The repeater may not use the allocated or duplicated received signal for measurement.

[0203] A repeater can use multiple beams for transmission. In the transmission using multiple beams, for example, a function of allocating and / or duplicating received signals can be used. Each of the multiple beams can be amplified and / or phase-shifted. Thus, for example, the reception quality in the UE can be improved for the signal sent from the repeater. In addition, it can be sent to multiple UEs at the same time, which can improve the efficiency in the communication system.

[0204] The repeater can use multiple beams for reception. The repeater can have the function of combining signals received from multiple beams. In the combining, the received signals of each beam can be amplified and / or phase-shifted. Thus, for example, the reception quality in the repeater can be improved. In addition, the ability to simultaneously receive signals from multiple UEs can improve the efficiency of the communication system.

[0205] The capability of a repeater may include information about the number of allocations and / or replications in the repeater, information about the number of transmit and / or receive beams that the repeater can simultaneously support, information about the above-mentioned amplification and / or phase shifting, and information about the noise figure in the amplification of the repeater.

[0206] The base station may instruct the repeater to allocate and / or replicate. The indication may include information related to the number of allocations and / or replications. The base station may, for example, use the above-mentioned capability to make the indication. The indication may, for example, be included in an indication from the base station regarding transmission and reception with the UE, or different signaling may be set and used in the indication. The different signaling may be RRC signaling, MAC signaling, or L1 / L2 signaling. The repeater may use the indication to perform the above-mentioned allocation and / or replication. Thus, for example, flexible control may be performed in the communication system.

[0207] The base station may notify the UE of information related to the allocation and / or duplication of the repeater. The notification may include information related to the noise figure of the repeater. The UE may use this information to correct the measurement results. For example, the UE may correct the power reduction due to the allocation of the repeater, and may also correct the SINR deterioration due to the duplication of the repeater. Thus, for example, the UE can properly derive the best beam in the measurement.

[0208] Fig.14 FIG. 2 is a diagram showing another example of the operation sequence of L1 measurement in a repeater. Fig.14 In the example shown, the UE is connected to the base station via the relay. Fig.14 In the example shown, the relay measures the same CSI-RS as the CSI-RS measured by the UE. Fig.14 In, with Fig.12 The same step numbers are assigned to the same processes, and common descriptions are omitted.

[0209] Fig.14 Steps ST1205, ST1207, ST1210 and Fig.12 In step ST1410, the relay measures the CSI-RS of step ST1207. That is, the relay itself can measure the CSI-RS of step ST1207 and transmit it to the UE.

[0210] Fig.14 Steps ST1215 to ST1223 shown are Fig.12 same.

[0211] exist Fig.14 In step ST1431 shown, the base station transmits an uplink grant to the relay. In step ST1433, the relay transmits CSI feedback to the base station. The CSI feedback in step ST1433 can be used to notify the measurement result in step ST1410.

[0212] The repeater may measure a signal different from the measurement signal for the UE. A measurement signal for measurement by the repeater may be provided.

[0213] The measurement signal for the repeater may be assigned a different identifier than the measurement signal for the UE. Thus, for example, complexity associated with the management of the measurement signal in the base station can be avoided. As another example, the measurement signal for the repeater may be assigned the same identifier as the measurement signal for the UE. Thus, for example, the base station can quickly grasp the association between the repeater and the UE.

[0214] Fig.15 FIG. 2 is a diagram showing another example of the operation sequence of L1 measurement in a repeater. Fig.15 In the example shown, the UE is connected to the base station via the relay. Fig.15 In the example shown, the relay measures a CSI-RS that is different from the CSI-RS measured by the UE. Fig.15 In, with Fig.12 , Fig.14 The same step numbers are assigned to the same processes, and common descriptions are omitted.

[0215] Fig.15 Steps ST1205 to ST1210 shown are Fig.12 same.

[0216] exist Fig.15 In step ST1512 shown, the base station transmits CSI-RS to the relay. In step ST1514, the relay measures CSI-RS.

[0217] exist Fig.15 Before step ST1512 shown in the figure, the base station may notify the relay of information related to the setting of the CSI-RS. The relay may receive the CSI-RS in step ST1512 using the information.

[0218] Fig.15 Steps ST1215 to ST1223 shown are Fig.12 same.

[0219] Fig.15 Steps ST1431, ST1433 and Fig.14 same.

[0220] Fig.15 , it is shown that the measurement in the UE is performed before the measurement in the relay, but the measurement in the relay can be performed before the measurement in the UE. Fig.15 , it is shown that the CSI feedback from the UE is performed before the CSI feedback from the repeater, but the CSI feedback from the repeater can be performed before the CSI feedback from the UE. Thus, for example, the base station can implement control for the UE in consideration of the radio wave propagation environment between the base station and the repeater, and as a result, the base station can efficiently perform control for the UE.

[0221] As another example of the measurement performed by the repeater, L3 measurement may be performed. The base station may notify the repeater of information related to the measured signal, and may also notify the repeater of information related to the measurement report. The repeater may use the information to perform L3 measurement. The repeater may notify the base station of the measurement result. The base station may use the information to perform control on the repeater.

[0222] The repeater can make a measurement report to the base station. The measurement report from the repeater to the base station can use RRC signaling, such as measurement report (MeasurementReport) signaling. This can avoid complexity in the design of the communication system, for example.

[0223] Fig.16 FIG. 1 is a diagram showing another example of the action sequence of L3 measurement in a repeater. Fig.16 In the example shown, the UE is connected to the base station via the relay and performs L3 measurements. Fig.16 In the example shown, the relay measures a CSI-RS that is different from the CSI-RS measured by the UE. Fig.16 In, with Fig.12 , Fig.13 , Fig.15 The same step numbers are assigned to the same processes, and common descriptions are omitted.

[0224] Fig.16 Steps ST1302, ST1304 and Fig.13 same.

[0225] exist Fig.16 In step ST1604 shown, the base station performs measurement settings for the repeater. This setting can be performed using L1 / L2 signaling, MAC signaling, or RRC signaling, such as RRC reconfiguration. The repeater can start CSI-RS measurement based on step ST1604.

[0226] Fig.16 Steps ST1205 to ST1210 shown are Fig.12 Steps ST1512 and ST1514 are the same as Fig.15 Steps ST1215 and ST1217 are the same as Fig.12 Steps ST1321 and ST1323 are the same as Fig.13 same.

[0227] exist Fig.16 In step ST1631 shown, the base station sends an uplink grant to the relay. In step ST1633, the relay performs a measurement report to the base station. The measurement report in step ST1633 may include, for example, the measurement result in step ST1514. In step ST1633, RRC signaling, such as a measurement report (MeasurementReport), may be used.

[0228] Fig.16 , the case where the CSI-RS measured by the UE and the CSI-RS measured by the relay are different is shown, but the UE and the relay can measure the same CSI-RS. In this case, for example, the relay can use Fig.14 The same setting as the measurement of step ST1410 shown in the figure is used to measure Fig.16 The CSI-RS of step ST1210 shown in the figure. This can save CSI-RS resources in the communication system, for example.

[0229] Fig.16 , it is shown that the measurement in the UE is performed before the measurement in the relay, but the measurement in the relay can be performed before the measurement in the UE. Fig.16, it is shown that the measurement report from the UE is performed before the measurement report from the repeater, but the measurement report from the repeater can be performed before the measurement report from the UE. Thus, for example, the base station can implement control for the UE in consideration of the radio wave propagation environment between the base station and the repeater, and as a result, the base station can efficiently perform control for the UE.

[0230] As another solution, the relay may transmit a measurement signal to the UE. The UE may measure the measurement signal transmitted from the relay, such as CSI-RS.

[0231] The base station may not send a downlink signal / channel in the time / frequency resources occupied by the measurement signal sent by the repeater. The repeater may attach the measurement signal to the signal received from the base station and send it to the UE. As another example, the repeater may send the measurement signal to the UE during the time when the base station uses a different beam than that facing the repeater.

[0232] Fig.17 This is a diagram showing a measurement signal transmitted from a repeater. Fig.17 In the example, the base station 1101 sends a PDSCH 1105 to the relay 1102. The base station 1101 sets the resource (e.g., RE) for sending the measurement signal 1707 to blank to send the PDSCH 1105. The relay 1102 receives the PDSCH 1105 from the base station, attaches the measurement signal 1707, and sends it to the UE 1103. The UE 1103 receives the PDSCH 1105 from the relay 1102 and measures the measurement signal 1707.

[0233] Fig.17 1707, an example of using CIS-RS as the measurement signal 1707 is shown, but an SS block may be used. Thus, for example, when UE 1103 is connected to another base station, the UE 1103 can perform measurement of the SS block transmitted via the relay 1102, and as a result, the UE 1103 can be connected to the base station 1101 via the relay 1102. Hereinafter, the description will be continued by omitting the reference numerals of the base station 1101, the relay 1102, and the UE 1103.

[0234] The base station may instruct the repeater to send a measurement signal. The indication may be made using FL. The indication may use L1 / L2 signaling, for example. A new DCI may be set. The indication may use a new DCI. Thus, for example, malfunctions caused by other UEs receiving DCI for the repeater may be prevented. As another example, the indication may use MAC signaling. Thus, for example, the base station may send more information to the repeater. As another example, the indication may use RRC signaling. Thus, for example, the base station may send more information to the repeater.

[0235] The indication may include, for example, information for identifying the measured measurement signal. The identifier may be, for example, an identifier of a CSI-RS or an identifier of an SS block. The indication may include information related to the resource of the measured measurement signal. The information about the resource may include, for example, information related to the PRB to which the measurement signal is allocated, information related to the code element, information related to the RE, information related to the period, and information related to the antenna port. The indication may include information related to the UE involved in the measurement, such as an identifier of the UE. The indication may include information required for coding generation. The repeater may use this information to perform coding generation of the measurement signal. Thus, for example, the amount of processing of the base station involved in coding generation can be reduced.

[0236] The measurement signal sent from the repeater to the UE and the measurement signal sent from the base station to the UE can use the same resource. The resource can be a time resource, a frequency resource, a coding resource, or a combination of multiple of the above. Thus, for example, the efficiency in the communication system can be improved. As another example, different resources can be used between the measurement signal sent from the repeater to the UE and the measurement signal sent from the base station to the UE. Thus, for example, the measurement signal sent from the repeater to the UE and the measurement signal sent from the base station to the UE can be easily identified.

[0237] The measurement performed by the repeater may be, for example, an L1 measurement. The measurement object in the L1 measurement of the relay may be, for example, the RSRP, RSRQ and / or SINR of the CIS, the RSRP, RSRQ and / or SINR of the SS block, or a combination of the above. The base station may notify the repeater of information related to the measurement object. The repeater may use the notification to perform the L1 measurement.

[0238] The measurement object may include received signal strength. The notification from the base station to the repeater may include information related to the received signal strength. Thus, for example, the repeater can quickly perform the measurement.

[0239] For the CSI-RS received from the relay, the UE can provide CSI feedback to the base station. The base station can use the feedback to control the relay, thereby, for example, reducing the amount of processing in the relay.

[0240] Fig.18 is a diagram showing an example of an action sequence of L1 measurement of a UE connected to a base station via a relay. Fig.18 An example of using CSI-RS in L1 measurement is shown. Fig.18 An example is shown in which a relay transmits a CSI-RS and a UE receives the CSI-RS. Fig.18 In, with Fig.12 The same step numbers are assigned to the same processes, and common descriptions are omitted.

[0241] exist Fig.18 In step ST1806 shown, the base station indicates the settings for CSI-RS transmission to the repeater. The indication may use L1 / L2 signaling, MAC signaling, RRC signaling, or a combination of the above. The indication may include, for example, information for identifying the measured measurement signal. The identifier may be, for example, an identifier of a CSI-RS or an identifier of an SS block. The indication may include information related to the resources of the measured measurement signal. The information about the resources may include, for example, information related to the PRB to which the measurement signal is allocated, information related to code elements, information related to REs, information related to periods, and information related to antenna ports. The indication may include information related to the UE involved in the measurement, such as an identifier of the UE. The indication may include information required for code generation. The repeater may use this information to perform code generation of the measurement signal. Thus, for example, the amount of processing of the base station involved in code generation can be reduced.

[0242] exist Fig.18 In step ST1808 shown, the relay transmits CSI-RS to the UE. The transmission of the CSI-RS from the relay may use the setting instructed by the base station in step ST1806. In step ST1210, the UE measures the CSI-RS.

[0243] Fig.18 Steps ST1215 to ST1223 shown are Fig.12 same.

[0244] As another example of the measurement, it may be L3 measurement. The base station may notify the UE of information related to the measured signal, and may also notify the UE of information related to the measurement report. The notification may include information related to the period of the measurement report, and may also include information related to the event that triggers the measurement report. The UE may use this information to perform L3 measurement. The UE may notify the base station of the measurement result. The notification from the UE to the base station may use RRC signaling, such as a measurement report (MeasurementReport). For example, the base station may use the notified measurement result to decide on the switching of the UE. Thus, for example, the UE can switch to another base station via a relay.

[0245] Fig.19 is a diagram showing an example of an action sequence of L3 measurement of a UE connected to a base station via a relay. Fig.19 An example of using CSI-RS in L3 measurement is shown. Fig.19 An example is shown in which a relay transmits a CSI-RS and a UE receives the CSI-RS. Fig.19 In, with Fig.12 , Fig.13 , Fig.18 The same step numbers are assigned to the same processes, and common descriptions are omitted.

[0246] Fig.19 Steps ST1302, ST1304 and Fig.13 Steps ST1806 and ST1808 are the same as Fig.18 Step ST1210 is the same as Fig.12 In step ST1210, the UE may measure multiple CSI-RSs.

[0247] Fig.19 Steps ST1215, ST1217 and Fig.12 Steps ST1321 and ST1323 are the same as Fig.13 same.

[0248] The methods disclosed in this embodiment 1 may be used in combination. For example, a combination of the measurement of the signal sent by the UE to the base station, the measurement of the signal sent by the repeater to the base station, and the measurement of the signal sent by the repeater to the UE may be used. In the above combination, one or more of the measurements may be L1 measurements, and one or more may be L3 measurements. In the above measurements, L1 measurements and L3 measurements may also be used in combination. Thus, for example, the flexibility in the communication system can be improved.

[0249] The method disclosed in Implementation Example 1 can be switched. For example, the sending of CSI-RS from the base station and the sending of CSI-RS from the repeater can be switched. The base station can notify the repeater of information related to the switching. For example, the information can be information indicating whether the CSI-RS from the base station is received and sent to the UE, or whether the CSI-RS is generated by the repeater itself. The repeater can use the information to receive the CSI-RS from the base station and send it to the UE, or the repeater can generate the CSI-RS and send it to the UE. The same is true for the SS block. Thus, for example, the flexibility of the communication system can be improved.

[0250] As another example, the measurement of CSI-RS in the repeater and the measurement of CSI-RS in the UE can be switched. The base station can notify the repeater of information related to the switch. For example, the information can be information indicating whether the measurement of CSI-RS is performed by the UE or the repeater. The repeater can use the information to receive the CSI-RS from the base station and send it to the UE, or the repeater can measure the CSI-RS. Thus, for example, the flexibility of the communication system can be improved.

[0251] According to the first embodiment, it is possible to perform measurement of UE connected to the base station via a repeater, and as a result, it is possible to smoothly control power and the like related to communication between the UE connected to the base station via a repeater and the base station.

[0252] Implementation method 2. To measure the uplink signal, the same method as in Embodiment 1 can be applied.

[0253] For example, a UE connected to a base station via a repeater may transmit an SRS, and the base station may receive the SRS. The repeater may receive the SRS transmitted by the UE and transmit the SRS to the base station. The repeater may amplify the SRS transmitted by the UE and transmit the SRS to the base station. The repeater may perform the amplification action and / or the transmission action together with the transmission action of other channels / signals.

[0254] The repeater can perform beamforming when receiving SRS from the UE, or when receiving other signals / channels from the UE. The repeater can perform beamforming when sending SRS to the base station, or when sending other signals / channels to the base station.

[0255] The base station may instruct the relay to transmit and receive data with the UE. The instruction may be performed using FL, for example. The instruction may be performed using L1 / L2 signaling, MAC signaling, or RRC signaling, for example. The instruction may include the above-mentioned information (1) to (14). The relay may use the information included in the instruction to receive the SRS from the UE and send it to the base station.

[0256] The base station can use the measurement results of the SRS to control the UE and / or the repeater. For example, the base station can determine the uplink transmission power of the UE, the uplink transmission power from the repeater, and the amplification factor in the repeater.

[0257] Fig. 20 : is a diagram showing an example of a sequence of actions in which a UE connected to a base station via a relay transmits an SRS and is received by the base station. Fig. 20 In the figure, the arrow with a black circle indicates that the signal transmission and reception between the base station and the UE is carried out via the repeater.

[0258] exist Fig. 20 In step ST2003 shown in FIG. 1 , the base station instructs the repeater to set the beam. The instruction may include information indicating that the downlink signal is to be transmitted and received. The instruction may be used in conjunction with Fig.12 In step ST2005, the base station sends the SRS setting for the UE to the relay, and the relay receives the setting from the base station and sends it to the UE.

[0259] exist Fig. 20 In step ST2011 shown in FIG. 1 , the base station instructs the repeater to set the beam. The instruction may include information indicating that the uplink signal is to be transmitted and received. The instruction may be used in conjunction with Fig.12 The same signaling as step ST1205 in step ST2013 is used. The UE transmits an SRS to the relay. The relay receives the SRS and transmits it to the base station. The SRS transmission in step ST2013 uses the SRS setting notified in step ST2005. In step ST2015, the base station measures the SRS transmitted from the UE via the relay.

[0260] The base station can set the transmission power of SRS for the repeater. This setting can be performed using FL, for example. This setting can use RRC signaling, MAC signaling, or L1 / L2 signaling. The repeater receives the SRS from the UE and sends the SRS to the base station at the set power. The repeater can send the SRS to the base station together with other signals / channels at the set power. The base station can receive the SRS sent from the repeater. Thus, for example, the base station can grasp the attenuation between the repeater and the base station.

[0261] As another example, the repeater can measure the SRS. A UE connected to the base station via the repeater can send the SRS, and the repeater can receive the SRS. The repeater can notify the base station of the measurement result of the SRS. Thus, for example, the base station can grasp the radio wave propagation environment between the UE and the repeater, and as a result, the UE and / or the repeater can be appropriately controlled.

[0262] The base station may instruct the repeater to measure the SRS. The instruction may include information related to the SRS measurement. The following (A) to (I) are disclosed as examples of the information.

[0263] (A) Information identifying the SRS.

[0264] (B) Information on the presence or absence of SRS measurement.

[0265] (C) Information related to the type of SRS.

[0266] (D) Information related to UE.

[0267] (E) Information on the beam used in SRS reception.

[0268] (F) Information related to the resources of the SRS.

[0269] (G) Information related to the measurement items.

[0270] (H) Information related to the reporting of measurement results.

[0271] (I) A combination of the above (A) to (H).

[0272] The information (A) above may be, for example, an identifier of an SRS. For example, the repeater can identify the SRS to be measured by using the information (A) above.

[0273] Regarding the information (B) above, the repeater can start SRS measurement upon receiving information indicating that SRS measurement is “yes”, and can stop SRS measurement upon receiving information indicating that SRS measurement is “no”. Thus, for example, the base station can switch whether or not the repeater performs SRS measurement.

[0274] The information in (C) above may include information indicating that the SRS transmission from the UE is periodic, may include information indicating that it is semi-permanent, and may include information indicating that it is aperiodic. The repeater may use the information in (C) above to determine whether the SRS measurement is periodic, semi-permanent, or aperiodic. Thus, for example, the repeater can perform appropriate measurements based on the type of SRS.

[0275] The information in (D) above may include, for example, information related to the identity of the UE. The relay may use this information to identify the UE that sends the SRS.

[0276] The information in (E) may include, for example, information on the identification of the beam used for receiving the SRS. The repeater can use this information to understand the beam used for receiving the SRS. This can improve the reliability of SRS reception in the repeater, for example.

[0277] The information in (F) above may include, for example, information related to the subcarrier spacing of the SRS, information related to the transmission symbol of the SRS, information related to the period of the SRS, information related to the carrier for transmitting the SRS, information related to the PRB and / or subcarrier for transmitting the SRS, information related to the coding of the SRS, and information related to the transmission power of the SRS. The information in (F) above may include information included in the SRS-config of non-patent document 19 (3GPP TS38.331). The repeater can use this information to obtain information related to the resources of the SRS. Thus, for example, the repeater can receive the SRS.

[0278] For example, the information of (G) above may be RSRP, RSRQ and / or SINR of SRS, or may be reception strength involved in SRS reception. The statistical value of the above value may be, for example, a moving average. The repeater may use this information to measure the SRS. Thus, for example, it is possible to prevent identification inconsistencies between the base station and the repeater related to the measurement of the SRS, and as a result, control of the repeater and / or UE based on the SRS measurement result may be properly performed.

[0279] The information in (H) may include, for example, information related to the signaling used in the report. The signaling may be L1 / L2 signaling (e.g., PUCCH), MAC signaling, or RRC signaling. The information in (H) may include information related to the resources (e.g., frequency, time) used in the signaling used for the report. The information in (H) may include information related to the reporting period, and may include information related to the event that serves as a trigger for the report. The event that serves as a trigger for the report may be, for example, the same as the event that serves as a trigger for a measurement report from the UE (refer to non-patent document 19 (3GPPTS38.331)). The information in (H) may include information related to the content of the report. The information on the content of the report may be, for example, the same as the information in (G) above.

[0280] The indication from the base station to the repeater may be made using FL. The indication may use L1 / L2 signaling, for example. A new DCI may be set. The indication may use a new DCI. Thus, for example, malfunctions caused by other UEs receiving DCI for the repeater may be prevented. As another example, the indication may use MAC signaling. Thus, for example, the base station may send more information to the repeater. As another example, the indication may use RRC signaling. Thus, for example, the base station may send more information to the repeater. A combination of the above signaling may be used.

[0281] The repeater may report the SRS measurement result to the base station. The report may be performed using FL. The report may use L1 / L2 signaling, for example. A new UCI may be set. Thus, for example, the repeater can quickly report the measurement result to the base station. As another example, the report may use MAC signaling. Thus, for example, the repeater can send more information to the base station. As another example, the report may use RRC signaling. Thus, for example, the repeater can send more information to the base station.

[0282] This report from the repeater to the base station can be performed using the information in (H) above.

[0283] The notification of the information included in the SRS setting and / or SRS measurement result report from the base station to the repeater may be related to multiple SRSs. The base station may set the repeater related to multiple SRSs, and may also set the SRS measurement result report related to multiple SRSs. Thus, for example, the repeater can perform measurements related to multiple SRSs sent from the UE.

[0284] Fig.21 1 is a diagram showing an example of a sequence of actions in which a UE connected to a base station via a relay transmits an SRS and is received by the relay. Fig.21 In, with Fig. 20 The same step numbers are assigned to the same processes, and common descriptions are omitted.

[0285] Fig.21 Steps ST2003, ST2005 and Fig. 20 same.

[0286] exist Fig.21 In step ST2111, the base station instructs the relay to set the reception of SRS. The instruction may include information related to (A) to (I) above. In step ST2111, L1 / L2 signaling, MAC signaling, RRC signaling, or a combination of the above may be used.

[0287] exist Fig.21 In step ST2113 shown, the UE transmits an SRS to the relay. The SRS transmission from the UE can use the SRS setting notified from the base station in step ST2005. In step ST2115, the relay measures the SRS transmitted from the UE. The measurement in step ST2115 can be performed using the information included in the reception setting instructed in step ST2111.

[0288] exist Fig.21 In step ST2117 shown, the relay notifies the base station of the SRS measurement result. The report in step ST2117 can be performed using, for example, the information (H) included in step ST2111. In step ST2117, L1 / L2 signaling, MAC signaling, or RRC signaling can be used.

[0289] As another example, the repeater can send an SRS. The repeater can generate an SRS by itself and send it to the base station. The base station can receive the SRS sent by the repeater. Thus, for example, the base station can grasp the radio wave propagation environment between the repeater and the base station, and as a result, the UE and / or the repeater can be properly controlled.

[0290] The base station may instruct the repeater to send SRS. The SRS sending instruction from the base station to the repeater may be performed using RRC signaling, such as RRC reconfiguration. The instruction may include information related to the configuration of the SRS. The instruction may be performed, for example, using the content included in SRS-config (see non-patent document 19).

[0291] As another example, the SRS transmission instruction from the base station to the relay may use MAC signaling or L1 / L2 signaling. Thus, for example, the base station can quickly instruct the relay to transmit the aperiodic SRS.

[0292] The SRS transmission instruction from the base station to the repeater can use a combination of the above signaling. For example, the base station can use RRC signaling to notify the SRS setting, and use L1 / L2 signaling to indicate the transmission of the SRS involved in the setting. Thus, for example, more information can be notified from the base station to the repeater, and quick instructions can be given.

[0293] Fig. 22 1 is a diagram showing an example of a sequence of actions in which a relay transmits an SRS and a base station receives the SRS.

[0294] exist Fig. 22 In step ST2205 shown, the base station instructs the relay to send the SRS. The instruction may include information related to the configuration of the SRS. The instruction may be performed using RRC signaling, such as RRC reconfiguration, MAC signaling, L1 / L2 signaling, or a combination of the above signaling.

[0295] exist Fig. 22 In step ST2207 shown, the repeater transmits an SRS to the base station. The transmission of the SRS from the repeater to the base station may use the information included in the instruction received in step ST2205. In step ST2211, the base station measures the SRS transmitted from the repeater.

[0296] The methods disclosed in this Embodiment 2 may be used in combination. For example, a combination of SRS transmission from the UE to the base station, SRS transmission from the UE to the repeater, and SRS transmission from the repeater to the base station may be used. Thus, for example, the base station can grasp the radio wave propagation environment between the repeater and the base station, and as a result, the UE and / or the repeater can be appropriately controlled.

[0297] The base station and the repeater can measure the same SRS. The repeater can measure the SRS sent by the UE and send the SRS to the base station. Thus, for example, SRS resources in the communication system can be saved. As another example, the base station and the repeater can measure different SRSs. The UE can respectively send the SRS used in the measurement of the base station and the SRS used in the measurement of the repeater. Thus, for example, complexity in the communication system can be avoided.

[0298] The method disclosed in Implementation 2 can be switched for use. For example, the sending of SRS from the UE and the generation and sending of SRS from the repeater can be switched. The base station can notify the repeater of information related to the switch. The information can be information indicating whether the UE sends the SRS or the repeater itself generates the SRS. The repeater can use the information to receive the SRS from the UE and send it to the base station, or the repeater can generate the SRS and send it to the base station. Thus, for example, the flexibility of the communication system can be improved.

[0299] As another example, the measurement of the SRS in the repeater and the measurement of the SRS in the base station can be switched. The base station can notify the repeater of information related to the switching. For example, the information can be information indicating whether the measurement of the SRS is performed by the base station or the repeater. The repeater can use the information to receive the SRS from the UE and send it to the base station, or the repeater can measure the SRS. Thus, for example, the flexibility of the communication system can be improved.

[0300] According to the second embodiment, SRS transmission can be performed from a UE connected to the base station via a relay, and as a result, the base station can appropriately control the UE connected to the base station via a relay and the relay.

[0301] In the present disclosure, a repeater (smart repeater) is described, but unless otherwise specified, it may be a reflector or a reconfigurable intelligent surface (RIS). Thus, for example, power consumption in a communication system can be reduced and the coverage of a base station can be expanded.

[0302] In the present disclosure, it is recorded as gNB or cell, but unless otherwise specified, it can be either gNB or cell.

[0303] The above-mentioned embodiments and their modifications are merely examples, and the embodiments and their modifications can be freely combined. In addition, arbitrary structural elements of the embodiments and their modifications can be appropriately changed or omitted.

[0304] For example, in each of the above embodiments and their variations, a subframe is an example of a time unit for communication in a fifth generation communication system. A subframe may be a scheduling unit. In each of the above embodiments and their variations, processing recorded in subframe units may be performed in TTI units, time slot units, sub-time slot units, and micro-time slot units.

[0305] For example, the methods disclosed in the above embodiments and their variations are not limited to V2X (Vehicle-to-everything) services, but can also be applied to services using SL communication. For example, they can be applied to SL communication used in various services such as proximity-based services, public safety, communication between wearable terminals, and communication between devices in factories. Description of symbols

[0306] 202 Communication terminal device (mobile terminal) 210 Communication System 213, 240-1, 240-2, 750, 801 base station device (NR base station, base station) 214 5G Core Department 215 Central Unit 216 Dispersed Units 217 Central unit for control layer 218 Central unit for user layer 219TRP 301, 403 protocol processing department 302 Application Department 304, 405 Coding Department 305, 406 Modulation Department 306, 407 frequency conversion unit 307-1~307-4、408-1~408-4 Antenna 308, 409 Demodulation Unit 309, 410 Decoding Department 310, 411, 526 control unit 401 EPC Communications Department 402 Other base station communication department 412 5GC Communications Department 521 Data Network Communications Department 522 Base Station Communication Department 523 User Layer Communication Department 523-1PDU Processing Unit 523-2 Mobile anchoring unit 525 Control layer control department 525-1NAS Security Department 525-2 Idle Mobility Management Department 527 Session Management Department 527-1PDU Session Control Unit 527-2UE IP address allocation department 751-1~751-8 beam 752 Community 803 Coverage 805, 806, 811, 812, 905, 906UE 807, 808UL / DL communication 810, 814SL communication 901IAB Host CU 902IAB Host DU 903, 904 IAB nodes.

Claims

1. A communication system, characterized in that: include: A base station, the base station is applied to a fifth generation wireless access system; as well as a repeater having a beamforming function and performing relay processing between the base station and the communication terminal, The base station transmits information on the beam used in the relay process to the repeater, and further transmits a reference signal used in measurement of mobility control of the communication terminal, When receiving the reference signal, the repeater forms a beam based on information related to the beam received from the base station and sends the reference signal to the communication terminal. When receiving a measurement result of the reference signal from the communication terminal, the repeater relays the measurement result of the reference signal to the base station.

2. The communication system according to claim 1, characterized in that The repeater further measures the reference signal received from the base station and transmits the measurement result to the base station.

3. A communication system, characterized in that: include: A base station, the base station is applied to a fifth generation wireless access system; as well as a repeater having a beamforming function and performing relay processing between the base station and the communication terminal, The base station transmits information on a beam used in the relay process to the repeater, and further transmits information on a reference signal used in a measurement for mobility control of the communication terminal, The repeater forms a beam based on information related to the beam received from the base station, and generates the reference signal based on information related to the reference signal and sends it to the communication terminal. When the measurement result of the reference signal is received from the communication terminal, the repeater relays the measurement result of the reference signal to the base station.

4. A communication system, characterized in that: include: A base station, the base station is applied to a fifth generation wireless access system; as well as a repeater having a beamforming function and performing relay processing between the base station and the communication terminal, The base station transmits information about a beam used in the relay process to the repeater, and further transmits information about a reference signal used in a measurement for mobility control of the communication terminal to the communication terminal via the repeater, The communication terminal generates and transmits the reference signal based on information related to the reference signal, When receiving the reference signal from the communication terminal, the repeater forms a beam based on the information on the beam received from the base station, and transmits the reference signal to the base station.

5. A communication system, characterized in that: include: A base station, the base station is applied to a fifth generation wireless access system; as well as a repeater having a beamforming function and performing relay processing between the base station and the communication terminal, The base station transmits information about a beam used in the relay process to the repeater, and further transmits information about a reference signal used in a measurement for mobility control of the communication terminal to the communication terminal via the repeater, The communication terminal generates and transmits the reference signal based on information related to the reference signal, The repeater measures the reference signal transmitted by the communication terminal, forms a beam based on the information on the beam received from the base station, and transmits the measurement result of the reference signal to the base station.

6. The communication system according to claim 5, characterized in that The relay further generates the reference signal based on the information related to the reference signal and transmits the reference signal to the base station.

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