Relay device, base station device, and wireless communication system

Abstract

Provided are a relay device, a base station device, a wireless communication system, and a relay method for expanding coverage of a communication range and eliminating coverage holes. A base station communication unit (11) receives, from a gNB (20), a plurality of signals of the same type having different contents. A communication control unit (14) assigns different transmission timings and different beams used in wireless communication to each of the signals received by the base station communication unit (11). A UE communication unit (16) transmits each of the signals to a UE (30), at a transmission timing assigned by the communication control unit (14), using a beam assigned by the communication control unit (14)

Description

[Technical Field]

[0001] The present invention relates to a relay device and a base station device. and wireless communication systems Regarding. [Background technology]

[0002] Currently, mobile terminal devices such as smartphones are widespread, and it is desirable for users to be able to access mobile communication networks regardless of their location. To access a mobile communication network using a mobile terminal device, the mobile terminal device must be located within the service area of the mobile communication network. Even within a service area, there are many blind spots and interference zones, such as in underground shopping malls and inside buildings. To address the issues of insufficient service areas and the blind and interference zones, a measure to eliminate the blind and interference zones has been taken, using a repeater device that uses a relay amplifier called a radio frequency (RF) repeater (Radio Frequency Repeater). In the following description, a wireless repeater will simply be referred to as a repeater. A repeater amplifies and relays radio waves transmitted from a base station to deliver them to a user equipment (UE).

[0003] Traditionally, repeaters have been used as relay nodes that simply amplify and forward received signals. The advantages of using repeaters include lower costs compared to base stations, ease of deployment due to the lack of license requirements for low-power applications, and minimal increase in latency. In other words, deploying repeaters is cost-effective for expanding coverage. On the other hand, the disadvantages of using repeaters include concerns about increased noise due to the repeater itself acting as an interference reducer, and the increased power consumption and potential for interference due to the repeater being constantly on.

[0004] Therefore, in 5G (5th generation mobile communications), which is being considered as the next-generation communication standard, a technology has been proposed that provides repeaters with side control information to efficiently expand network coverage. This technology allows repeaters to perform beamforming control, timing control, UL (Up Link) / DL (Down Link) TDD (Time Division Duplex) configuration settings, on / off control, power control, and more.

[0005] Beamforming is also one of the technologies attracting attention in 5G. This technology uses multiple antenna elements on a single antenna to work together to form a radio wave beam in any direction, thereby expanding the coverage area and increasing cell capacity through simultaneous communication with multiple users.

[0006] There are two types of beamforming: digital beamforming and analog beamforming. Digital beamforming has the advantage of being able to increase capacity and being highly flexible, but the disadvantage is that the configuration is complicated. Analog beamforming has the advantage of being simple to configure, but the disadvantage is that it transmits one beam at a time.

[0007] It is possible to secure the communication distance and area between the base station and UE by using transmit beamforming at the base station. By applying beamforming, the signal reception strength is concentrated in a specific direction, which can extend the communication distance, but the reception strength decreases in other directions, which narrows the range the signal can reach.

[0008] Here, it is preferable to transmit synchronization signals (SS) and broadcast channels (PBCH: Physical Broadcast Channel) so that they reach all mobile terminal devices within a cell. Therefore, in NR, synchronization signals and PBCHs are defined as a single unit, the SS / PBCH Block (SSB). A configuration has been proposed in which one SSB is transmitted using a transmission beam in the same direction, and multiple SSBs are transmitted by sequentially switching the beam direction (beam sweeping). Base stations use SSBs to provide UEs with important functions such as initial access and mobility. Network operators can set the SSB transmission timing and transmission cycle for each base station and notify the UEs of these settings.

[0009] Furthermore, with the aim of achieving faster and wider bandwidth in wireless communications, the use of millimeter waves for communication is being considered for 5G. However, while millimeter wave communication has the advantages of high speed and wide bandwidth, it also has disadvantages such as a narrow communication range and susceptibility to obstacles. Therefore, repeaters are used to overcome these disadvantages of millimeter waves.

[0010] A technology called IAB (Integrated Access and Backhaul) has been developed to extend the communication distance of millimeter wave communications and expand coverage to areas that would otherwise be blind spots. IAB is a wireless access backhaul integrated transmission technology that enables millimeter wave communications to operate like a relay between multiple New Radio (NR) base stations. IAB enables flexible and inexpensive network design by applying NR to backhaul link communications. However, repeaters do not require licenses under certain conditions and are easier to introduce than IAB, which has the advantage of allowing for more flexible network design.

[0011] As a repeater technology, a technology has been proposed in which configuration information relating to an access procedure is received from a base station and a signal is transferred to another wireless communication device based on the received access procedure. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] US Patent Application Publication No. 2021 / 0298069 Summary of the Invention [Problem to be solved by the invention]

[0013] In conventional wireless communication systems, base stations transmit signals using different beams for each SSB, and UEs select the beam with the highest received power to communicate with the base station. Therefore, when repeaters are used to expand millimeter wave coverage, it is desirable to apply beamforming to the repeaters as well. Repeaters relay signals such as SSBs from base stations, allowing UEs to connect to the base station via the repeater.

[0014] However, with analog beamforming, it is difficult to simultaneously transmit multiple SSBs within the same cell. Because the repeater is located in one of the multiple cells formed by the base station using each beam, only one SSB is transmitted to the repeater. In a conventional configuration in which the repeater transmits one beam, if the repeater simply relays the signal using the optimal beam from the base station, one SSB will be transmitted to the UE via one beam, making it difficult to provide sufficient coverage.

[0015] One possible solution is to equip the repeater with a configuration that transmits multiple beams to improve the efficiency of coverage expansion. However, if the repeater transmits SSBs to the UE using different beams at different intervals than the SSBs periodically transmitted by the base station, the UE will no longer have a one-to-one relationship between the beam and the SSB, making it difficult for the UE to operate correctly. As a result, coverage expansion will be incomplete in practice.

[0016] The disclosed technology has been made in consideration of the above, and aims to provide a relay device, a base station device, a wireless communication system, and a relay method that expand the coverage of the communication range and eliminate coverage holes. [Means for solving the problem]

[0017] In one aspect of the relay device, base station device, and wireless communication system disclosed herein, a first communication unit receives a plurality of signals from a first wireless communication device. A communication control unit assigns a transmission timing and a beam to be used for wireless communication corresponding to each of the plurality of signals received by the first communication unit. A second communication unit transmits each of the plurality of signals to a second wireless communication device at the transmission timing assigned by the communication control unit using the beam assigned by the communication control unit. The communication control unit assigns a beam index indicating the beam. information on the transmission timings assigned to each of the plurality of signals; The first information includes Downlink control information including Receive. [Effects of the Invention]

[0018] In one aspect, the present invention can extend communication range coverage and eliminate coverage holes. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is an overall diagram of a communication system using beamforming with a repeater. [Figure 2] Figure 2 is a block diagram of a gNB and a repeater. [Figure 3] FIG. 3 is a diagram showing an example of the configuration of the newly established format of DCI. [Figure 4] FIG. 4 is a diagram showing another example of the configuration of the newly established format of DCI. [Figure 5] FIG. 5 is a diagram for explaining SSB transmission. [Figure 6] FIG. 6 is a flowchart of the initial connection between the gNB and the repeater according to the first embodiment. [Figure 7] FIG. 7 is a flowchart of a communication process after an initial connection is established by the wireless communication system according to the first embodiment. [Figure 8] FIG. 8 is a flowchart of a communication process after an initial connection is established by the wireless communication system according to the second embodiment. [Figure 9] Figure 9 is a flowchart of the initial connection between the gNB and the repeater in accordance with the third embodiment. [Figure 10] FIG. 10 is a flowchart of a communication process after an initial connection is established by the wireless communication system according to the third embodiment. [Figure 11] FIG. 11 is a flowchart of a communication process after an initial connection is established by the wireless communication system according to the fourth embodiment. [Figure 12] FIG. 12 is a diagram for explaining the operation when different beams at different timings are used to transmit multiple CSI-RSs. DETAILED DESCRIPTION OF THE INVENTION

[0020] The following describes in detail exemplary embodiments of the relay device, base station device, wireless communication system, and relay method disclosed herein with reference to the accompanying drawings. Note that the relay device, base station device, wireless communication system, and relay method disclosed herein are not limited to the following exemplary embodiments. [Example]

[0021] 1 is an overall diagram of a wireless communication system using beamforming and having a repeater. The wireless communication system 1 according to this embodiment includes a repeater 10 which is a relay device, a gNB 20 which is a radio base station device of NR, and a UE 30 which is a mobile terminal device.

[0022] The gNB 20 transmits signals by beams using beamforming. For example, the gNB 20 transmits beams 41 to 45 using TDM (Time Division Multiplexing) transmission, transmitting each beam in a different direction at a different timing. Each beam forms a different cell.

[0023] Furthermore, the gNB 20 uses SSB to provide important functions for initial access and mobility, specifically, synchronization signals, broadcast channels, and indexes such as radio frame timing and slot timing, to the UE 30 via the repeater 10. After establishing a connection with the UE 30 via the repeater 10 for data communication, the gNB 20 transmits and receives data to and from the UE 30 via the repeater 10. In FIG. 1, for example, the gNB 20 communicates with the repeater 10 using beam 43 as the optimal beam. This gNB 20 is an example of a "first wireless communication device." The UE 30 is an example of a "second wireless communication device."

[0024] Repeater 10 receives a signal transmitted from gNB 20 using beamforming. Repeater 10 then amplifies the received signal and forwards the signal to the UE using a beam formed by beamforming. Repeater 10 also amplifies a signal received from UE 30 and forwards it to gNB 20.

[0025] 2 is a block diagram of the gNB and the repeater. Details of the gNB 20 and the repeater 10 will be described below with reference to FIG. 2.

[0026] The gNB 20 includes an RRC (Radio Resource Control) connection implementation unit 21, a communication setting information transmission unit 22, a communication control unit 23, a data transmission / reception unit 24, and a communication unit 25. The RRC connection implementation unit 21, the communication setting information transmission unit 22, the communication control unit 23, and the data transmission / reception unit 24 are realized by a processor and a memory. The processor includes, for example, a CPU (Central Processing Unit), an FPGA (Field Programmable Gate Array), or a DSP (Digital Signal Processor). The communication unit 25 is realized by a processor and a wireless communication circuit.

[0027] The communication unit 25 performs wireless communication with the repeater 10 using analog beamforming. The communication unit 25 relays communication between the repeater 10 and each of the initial connection implementation unit 21, the communication setting information transmission unit 22, the communication control unit 23, and the data transmission / reception unit 24. The communication unit 25 performs processing such as frequency upconversion, quadrature modulation, and amplification on the downlink signals output from each unit. The communication unit 25 then wirelessly transmits the processed downlink signals as beams via an antenna during the transmission period of the downlink signals. The communication unit 25 also receives uplink signals in a predetermined frequency band via an antenna during the transmission period of the uplink signals. The communication unit 25 then performs processing such as amplification, quadrature demodulation, and downconversion on the received uplink signals, and outputs the processed uplink signals.

[0028] However, in the following explanation, the relaying by the communication unit 25 may be omitted, and it may be explained as if each of the RRC connection implementation unit 21, communication setting information transmission unit 22, communication control unit 23, and data transmission / reception unit 24 transmits and receives signals to and from the repeater 10.

[0029] The RRC connection implementation unit 21 executes an initial connection procedure with the repeater 10 to establish an RRC connection. For example, the RRC connection implementation unit 21 receives an RA preamble, transmits an RA response, receives an RRC connection request, transmits an RRC connection establishment notification, and transmits an RRC connection completion notification. At this time, an optimal beam is selected for communication between the gNB 20 and the repeater 10. Thereafter, the gNB 20 and the repeater 10 communicate using the selected optimal beam. When the RRC connection is completed, the RRC connection implementation unit 21 transmits a notification of the RRC connection establishment to the communication setting information transmission unit 22.

[0030] The communication setting information transmitter 22 receives a notification of RRC connection establishment from the initial connection implementation unit 21. Then, the communication setting information transmitter 22 transmits communication setting information including information for receiving DCI (Downlink Control Information), which is downlink control information, to the repeater 10 using the RRC protocol. The information for receiving DCI includes information such as frequency resources for transmitting DCI.

[0031] The communication control unit 23 acquires performance information of the repeater 10 transmitted from the repeater 10. The performance information of the repeater 10 includes information on the presence or absence of a repeater function for notifying that the source device is a repeater, the number of beams that can be transmitted and received, etc. Here, the period from when the RRC connection is established until when the gNB 20 transmits communication setting information to the repeater 10 and receives performance information from the repeater 10 is referred to as the initial connection.

[0032] Next, the communication control unit 23 generates a DCI for beam ID (Identifier) notification to notify the repeater 10 of operation information indicating the beam number of the beam used for transmission to the UE 30 in each symbol of each slot, according to the performance information of the repeater 19. The DCI for beam ID notification has a newly set DCI format. This DIC for beam ID notification is an example of first information indicating the transmission timing and beam to be assigned to each signal to transmit, such as SSB.

[0033] Then, the communication control unit 23 transmits a DCI for beam ID notification to the repeater 10 to notify the repeater 10 of operation information for each slot. The operation information included in the DCI for beam ID notification includes a beam ID that specifies the beam to be used in each symbol of the slot for each slot number. The beam ID may also be called a spatial filter ID or a spatial domain filter ID.

[0034] 3 is a diagram showing an example of the configuration of a newly configured DCI format. For example, as shown in FIG. 3, the newly configured DCI format used for beam ID notification contains a slot number and a slot interval. Furthermore, this format stores information indicating a starting symbol number, a symbol length, a beam ID, and downlink or uplink. However, as long as it is possible to indicate the correspondence between a specific slot and symbol and a specific beam, the newly configured DCI format may be configured to include part of the information shown in FIG. 3. In this case, the beam ID notification DCI is generated for each combination of slot and symbol and sent to the repeater 10.

[0035] FIG. 4 is a diagram showing another example of the configuration of a newly set format of DCI. Here, for example, slot #n is shown as slot #n, and symbol ##0 is shown as symbol ##0. As shown in FIG. 4, the newly set format of DCI may be created so that a beam ID to be used for each symbol for each slot is specified by a bitmap. In this case, the communication control unit 23 registers a beam ID and an indication of downlink or uplink (DLUL) represented by a bitmap in correspondence with the pair of slot and symbol shown on the left side of FIG. 4. For example, the beam to be used for symbol ##0 of slot #n is represented by six bits written on the right side of the page.

[0036] Thereafter, the communication control unit 23 performs scheduling by transmitting an SIB to be transmitted to the UE 30 using a specific beam to the repeater 10 in a slot and symbol that specifies the use of that specific beam. In this case, the communication control unit 23 transmits the SIB using DCI format 0. Furthermore, the communication control unit 23 transmits an SSB to be transmitted to the UE 30 using a specific beam to the repeater 10 using DCI in a slot and symbol that is specified by the SIB. This slot and symbol are the slot and symbol that specifies the use of that specific beam. The communication control unit 23 transmits the SSB using resources for four symbols.

[0037] FIG. 5 is a diagram for explaining the transmission of SSBs. The communication control unit 23 transmits, for example, a maximum of 64 SSBs in a 20 ms cycle. In FIG. 5, the interval between each of times t1, t2, and t3 is 20 ms. The communication control unit 23 transmits SSBs in order starting from time t1. In FIG. 5, the communication control unit 23 repeats the transmission of SSBs #0, #1, #2, ... in order in a 20 ms cycle. However, the maximum number of transmittable SSBs is 64, and the communication control unit 23 may transmit 64 or less SSBs. In FIG. 5, beam 43 is the optimal beam between the gNB 20 and the repeater.

[0038] The communication control unit 23 transmits SSB #0 using beam 41 and transmits SSB #1 using beam 42. Next, the communication control unit 23 TDM-transmits each of SSB #2 to #5 using beam 43. For example, the communication control unit 23 transmits SSB #2 using beam 43 at time t+n1. The communication control unit 23 also transmits SSB #3 using beam 43 at time t+n2. The communication control unit 23 also transmits SSB #4 using beam 43 at time t+n3. The communication control unit 23 also transmits SSB #5 using beam 43 at time t+n4.

[0039] Thereafter, the communication control unit 23 repeatedly notifies the beam ID of the beam to be used in each slot and symbol using the DCI for beam ID notification while establishing a connection for data communication and transmitting data, and until the connection is disconnected. For example, the communication control unit 23 receives the signal strength for each SSB transmitted from the UE 30, determines the beam to be used, and establishes a connection for data communication. Thereafter, the communication control unit 23 notifies the data transceiver unit 24 of the establishment of a connection for data communication with the UE 30. Furthermore, the communication control unit 23 notifies the data transceiver unit 24 of a schedule indicating the slots and symbols for transmitting the beams to be used in communication with the UE 30.

[0040] The data transmitter / receiver 24 receives a notification that a connection for data communication with the UE 30 has been established. Furthermore, the data transmitter / receiver 24 receives a schedule indicating slots and symbols for transmitting beams used in communication with the UE 30. The data transmitter 24 then transmits data to the UE 30 according to the notified schedule.

[0041] Next, the repeater 10 will be described. The repeater 10 according to this embodiment has the same function as a mobile terminal device such as a UE 30, such as establishing an initial connection with a gNB 20. The repeater 10 also performs wireless communication with the UE 30 using analog beamforming. The repeater 10 includes a base station communication unit 11, an RRC connection implementation unit 12, a performance information notification unit 13, a communication control unit 14, a transfer unit 15, and a UE communication unit 16. The RRC connection implementation unit 12, the performance information notification unit 13, the communication control unit 14, and the transfer unit 15 are realized by a processor and a memory. The processor includes, for example, a CPU, an FPGA, or a DSP. The base station communication unit 11 and the UE communication unit 16 are realized by a processor and a wireless communication circuit.

[0042] The base station communication unit 11 transmits and receives signals to and from the communication unit 25 of the gNB 20 using beams. For example, the base station communication unit 11 receives multiple different SSBs by TDM transmission. The base station communication unit 11 outputs the signal received from the gNB 20 to the performance information notification unit 13, the communication control unit 14, or the transfer unit 15 depending on the destination. The base station communication unit 11 also acquires a signal to be transmitted to the gNB 20 from the performance information notification unit 13, the communication control unit 14, or the transfer unit 15, and transmits it to the communication unit 25 of the gNB 20. In the following description, the base station communication unit 11 may be omitted, and the RRC connection implementation unit 12, the performance information notification unit 13, the communication control unit 14, and the transfer unit 15 may be described as communicating with the gNB 20. This base station communication unit 11 is an example of a "first communication unit."

[0043] The RRC connection implementation unit 12 executes an initial connection procedure to establish an RRC connection with the gNB 20. For example, the RRC connection implementation unit 12 transmits an RA preamble, receives an RA response, transmits an RRC connection request, receives an RRC connection establishment notification, receives an RRC connection completion notification, etc. The RRC connection implementation unit 12 also notifies the performance information notification unit 13 of the establishment of the RRC connection.

[0044] The performance information notification unit 13 receives a notification of the establishment of the RRC connection from the RRC connection implementation unit 12. Next, the performance information notification unit 13 transmits to the gNB 20 performance information of the repeater 10, including information that the repeater 10 has a repeater function and the number of beams that can be transmitted and received.

[0045] After the RRC connection has been established, the communication control unit 14 receives communication setting information for receiving DCI from the communication setting information transmission unit 22 of the gNB 20 via the base station communication unit 11. After this, the communication control unit 14 receives DCI in accordance with settings such as the frequency resource for transmitting DCI, which are included in the communication setting information.

[0046] The communication control unit 14 acquires the DCI for beam ID notification. Then, the communication control unit 14 acquires operation information for each slot included in the received DCI for beam ID notification and checks the beam ID of the beam used in each symbol for each slot specified by the operation information. If there is a range of slots for which the beam ID is specified by the DCI for beam ID notification, the communication control unit 14 sequentially acquires DCI for beam ID notification for slots in the following range and repeats checking the beam used in each symbol for each slot.

[0047] The communication control unit 14 then determines the slot and packet used by the signal received by the base station communication unit 11 from the communication unit 25 of the gNB 20, and identifies the beam ID of the beam corresponding to the slot and packet. The communication control unit 14 then notifies the UE communication unit 16 of the slot and packet information and the identified beam ID, and instructs the UE communication unit 16 to use the identified beam for transmitting the signal in that slot and packet.

[0048] For example, when the base station communication unit 13 receives an SIB, the communication control unit 14 identifies a beam corresponding to the slot and symbol of the signal. Then, the communication control unit 14 instructs the UE communication unit 16 to transmit a signal to the UE 30 using the identified beam in the slot and symbol for transmitting the SIB. Here, since an RRC connection is established between the repeater 10 and the gNB 20, the communication control unit 14 can obtain, from the SIB, information on the reception timing of the signal sent from the UE 30 relative to the signal to be transmitted.

[0049] Furthermore, upon receiving an SSB, the communication control unit 14 identifies a beam corresponding to the slot and symbol of the signal, and then instructs the UE communication unit 16 to transmit a signal to the UE 30 using the identified beam in the slot and symbol for transmitting the SSB.

[0050] The transfer unit 15 receives a signal transmitted from the gNB 20 via the base station communication unit 11. Then, the transfer unit 15 outputs the signal to the UE communication unit 16 so as to transmit the signal in the slot and symbol in which the signal was received. The transfer unit 15 also receives a signal transmitted from the UE 30 via the UE communication unit 16. Then, the transfer unit 15 outputs the signal to the base station communication unit 11 so as to transmit the signal in the slot and symbol in which the signal was received.

[0051] The UE communication unit 16 transmits and receives signals to and from the UE 30 using beamforming. The UE communication unit 16 transmits the signals output from the transfer unit 15 to the UE 30 using beams. The UE communication unit 16 also receives signals transmitted from the UE 30 and outputs them to the transfer unit 15.

[0052] The UE communication unit 16 receives notification of the beam ID of the beam used for transmission in each symbol for each slot from the communication control unit 14. The UE communication unit 16 also receives input of a signal to be transmitted in each symbol for each slot from the transfer unit 15. The UE communication unit 16 then transmits the signal input from the transfer unit 15 to the UE 30 in the slot and symbol for transmitting the signal, using a beam to which a beam ID corresponding to the slot and symbol for transmitting the signal is assigned. For example, the UE communication unit 16 transmits an SIB or an SSB to the UE 30 in the respective slot and symbol, using a beam specified in the slot and packet for transmitting the SIB or SSB. This UE communication unit 16 is an example of a "second communication unit."

[0053] 5, the communication control unit 14 notifies the UE communication unit 16 that beam 101 is to be used for the slot and symbol of the signal transmitted at time t1+n1. The UE communication unit 16 acquires SSB#2 transmitted at time t1+n1 from the transfer unit 15 and transmits it to the UE 30 using beam 101 in the received slot and symbol. The communication control unit 14 also notifies the UE communication unit 16 that beam 102 is to be used for the slot and symbol of the signal transmitted at time t1+n2. The UE communication unit 16 acquires SSB#3 transmitted at time t1+n2 from the transfer unit 15 and transmits it to the UE 30 using beam 102 in the received slot and symbol. The communication control unit 14 also notifies the UE communication unit 16 that beam 103 is to be used for the slot and symbol of the signal transmitted at time t1+n3. The UE communication unit 16 acquires SSB#4 sent at time t1+n3 from the transfer unit 15 and transmits it to UE 30 using beam 103 in the received slot and symbol. In addition, the communication control unit 14 notifies the UE communication unit 16 that beam 104 will be used in the slot and symbol of the signal sent at time t1+n4. The UE communication unit 16 acquires SSB#5 sent at time t1+n4 from the transfer unit 15 and transmits it to UE 30 using beam 104 in the received slot and symbol.

[0054] Fig. 6 is a flowchart of the initial connection between the gNB and the repeater according to embodiment 1. Next, the flow of the initial connection between the gNB 20 and the repeater 10 according to this embodiment will be described with reference to Fig. 6.

[0055] The RRC connection implementation unit 21 of the gNB 20 and the RRC connection implementation unit 12 of the repeater 10 execute an initial connection procedure to establish an RRC connection (step S101).

[0056] After the RRC connection is established, the performance information notification unit 13 of the repeater 10 transmits performance information of the repeater 10, including the presence or absence of a repeater function and the number of beams that can be transmitted and received, to the gNB 20 (step S102).

[0057] Next, the communication setting information transmitter 22 of the gNB 20 receives a notification of the completion of the RRC connection from the initial connection implementation unit 21. Then, the communication setting information transmitter 22 of the gNB 20 transmits communication setting information for receiving DCI to the communication control unit 14 of the repeater 10 (step S103). This allows the communication control unit 14 of the repeater 10 to receive DCI in accordance with the settings notified in the received communication setting information.

[0058] Fig. 7 is a flowchart of communication processing after initial connection establishment by the wireless communication system according to the first embodiment. Next, with reference to Fig. 7, the flow of communication processing after initial connection establishment by the wireless communication system 1 according to the first embodiment will be described. In Fig. 7, the beam used in communication between the repeater 10 and the UE 30 is shown in parentheses following the transmitted information. Hereinafter, the communication unit 25 of the gNB 20 communicates with the repeater 10 using the optimal beam between them.

[0059] The communication control unit 23 of the gNB 20 transmits operation information for slots #n+1 to #n+9 at symbol ##0 of slot #n using DCI for beam ID notification to the repeater 10 via the communication unit 25. The communication control unit 14 of the repeater 10 receives the DCI for beam ID notification at symbol ##0 of slot #n and acquires the operation information for slots #n+1 to #n+9 (step S111). At this time, the operation information for slots #n+1 to #n+9 transmitted by the communication control unit 23 includes information such as using beam B0 at symbol ##0 of slot #n+1 and using beam B1 at symbol ##1 of slot #n+1. Furthermore, the operation information for slots #n+1 to #n+9 includes information such as using beam B0 at symbols ##4-7 of slot #n+1 and using beam B0 at symbols ##8-11 of slot #n+1.

[0060] Next, at symbol ##0 of slot #n+1, the communication control unit 23 of the gNB 20 transmits an SIB to the repeater 10 using DCI format 0 to perform scheduling (step S112).

[0061] Since the signal has been transmitted at symbol ##0 of slot #n+1, the communication control unit 14 of the repeater 10 determines that beam B0 should be used and instructs the UE communication unit 16 to use beam B0 when transmitting the signal at symbol ##0 of slot #n+1 to the UE 30. The transfer unit 15 of the repeater 10 outputs the scheduling of the SIB received via the base station communication unit 11 to the UE communication unit 16 so that it is transmitted at symbol ##0 of slot #n+1. Then, in accordance with the instruction from the communication control unit 14, the UE communication unit 16 transmits the SIB to the UE 30 using beam B0 at symbol ##0 of slot #n+1 to perform scheduling (step S113).

[0062] Next, at symbol ##1 of slot #n+1, the communication control unit 23 of the gNB 20 transmits the SIB to the repeater 10 using DCI format 0 (step S114).

[0063] Since the signal has been transmitted at symbol ##1 of slot #n+1, the communication control unit 14 of the repeater 10 determines that beam B1 should be used and instructs the UE communication unit 16 to use beam B1 when transmitting the signal at symbol ##1 of slot #n+1 to the UE 30. The transfer unit 15 of the repeater 10 outputs the SIB received via the base station communication unit 11 to the UE communication unit 16 so that it is transmitted at symbol ##1 of slot #n+1. Then, in accordance with the instruction from the communication control unit 14, the UE communication unit 16 transmits the SIB to the UE 30 using beam B1 at symbol ##1 of slot #n+1, thereby performing scheduling (step S115).

[0064] Next, in symbols ##4-7 of slot #n+1, the communication control unit 23 of the gNB 20 transmits SSB#0 to the repeater 10 using DCI (step S116). In this embodiment, four symbols are used to transmit the SSB.

[0065] The communication control unit 14 of the repeater 10 determines that beam B0 should be used because the signal was transmitted at symbols ##4-7 of slot #n+1. The communication control unit 14 then instructs the UE communication unit 16 to use beam B0 when transmitting the signal at symbols ##4-7 of slot #n+1 to the UE 30. The transfer unit 15 outputs the SSB#0 received via the base station communication unit 11 to the UE communication unit 16 so that it should be transmitted at symbols ##4-7 of slot #n+1. In accordance with the instruction from the communication control unit 14, the UE communication unit 16 transmits SSB#0 to the UE 30 using beam B0 at symbols ##4-7 of slot #n+1 (step S117).

[0066] Next, in symbols ##8-11 of slot #n+1, the communication control unit 23 of the gNB 20 transmits SSB#1 to the repeater 10 using DCI (step S118).

[0067] Since the signal was transmitted using symbols ##8-11 of slot #n+1, the communication control unit 23 determines that beam B1 should be used and instructs the UE communication unit 16 to use beam B1 when transmitting the signal using symbols ##8-11 of slot #n+1 to UE 30. The transfer unit 15 outputs SSB#1 received via the base station communication unit 11 to the UE communication unit 16 so that it should be transmitted using symbols ##8-11 of slot #n+1. In accordance with the instruction from the communication control unit 23, the UE communication unit 16 of the repeater 10 transmits SSB#1 to UE 30 using beam B1 using symbols ##8-11 of slot #n+1 (step S119).

[0068] Thereafter, in slots #n+2 to #n+9, the repeater 10 transmits the signal transmitted from the gNB 20 to the UE 30 using the beam specified by the operation information.

[0069] Then, after slot #9 in which the operation information was transmitted ends, at symbol ##0 of the next slot #n+10, the communication control unit 23 of the gNB 20 transmits operation information for slots #n+11 to #n+19 to the repeater 10 via the communication unit 25 using DCI for beam ID notification. The communication control unit 14 of the repeater 10 receives DCI for beam ID notification at symbol ##0 of slot #n+10 and acquires the operation information for slots #n+11 to #n+19 (step S120). Thereafter, the repeater 10 transmits signals to the UE 30 using the beams specified in the operation information from slots #n+11 to #n+19. Thereafter, the gNB 20 repeats transmitting the operation information for each slot. The repeater 10 repeats transmitting signals to the UE 30 using the beams specified in the operation information for each slot.

[0070] In Figure 7, part of the communication when a connection is established is explained as an example, but the gNB 20 and repeater 10 also perform data transmission and reception and communication when the connection is disconnected in the same way.

[0071] As described above, in the communication system according to this embodiment, the repeater has the functionality of a UE and can establish an RRC connection with the gNB. This enables the repeater to receive control signals from the gNB via the UE functionality. The gNB then transmits DCI for beam ID notification to the repeater, and schedules the beams that the repeater will use for each symbol per slot. The gNB then transmits multiple SSBs to the repeater via TDM using the optimal beam between the gNB and the repeater. The repeater then transmits separate SSBs to the UE using each beam according to the set schedule.

[0072] This allows the UE to recognize the beam and SSB in a one-to-one relationship, and even in a configuration where beams are switched sequentially to expand coverage when communicating using beamforming, the gNB and UE can communicate appropriately via a repeater. This also makes it possible to reduce dead zones, eliminate coverage holes, and provide wide coverage when communicating using millimeter waves.

[0073] Furthermore, in the wireless communication system according to this embodiment, the use of repeaters allows for easier installation and a more flexible and inexpensive network design than the IAB. [Example]

[0074] Next, a second embodiment will be described. The wireless communication system 1 according to this embodiment differs from the first embodiment in that the gNB 20 instructs the repeater 10 using RRC parameters, which are parameters used at the time of establishing a connection for controlling wireless resources, until the SSB transmission and reception of msg.1. The wireless communication system 1 according to this embodiment is also represented by the block diagram of Fig. 2. In the following description, the operation of each unit similar to that of the first embodiment will be omitted.

[0075] The communication control unit 23 of the gNB 20 notifies the communication control unit 14 of the repeater 10 of the reception timing of the SSB and msg.1 / A, the beam ID, the transmission timing of each SSB, and the use timing of the beam using RRC parameters. Specifically, the communication control unit 23 includes information on the SSB, the beam ID, and the slot and symbol used for transmission in the RRC parameters and transmits them to the communication control unit 14 of the repeater 10. The communication control unit 23 causes the communication control unit 14 of the repeater 10 to read the SIB for the UE 30, thereby allowing the communication control unit 14 to know the reception timing of msg.1 / A. Here, the information included in the RRC parameters may be configured to include part of the above-mentioned information, as long as it is possible to indicate the correspondence between a specific slot and symbol and a specific beam or SSB.

[0076] After receiving msg.1 / A, the communication control unit 23 notifies the communication control unit 14 of the beam ID of the beam used in each symbol for each slot using DCI for beam ID notification. The format of the DCI for beam ID notification used in this embodiment can also be the format shown in Fig. 3. However, in the case of the format shown in Fig. 4, the scheduling related to SSB and msg.1 / A overlaps with the scheduling notified by the RRI parameters, so the use of the format shown in Fig. 4 is not suitable for the wireless communication system 1 according to this embodiment.

[0077] The communication control unit 14 of the repeater 10 receives the SSB, the beam ID, and the RRC parameters including information on the slot and symbol used for transmission. The communication control unit 14 then notifies the UE communication unit 16 of the beam ID specified by the RRC parameters in each symbol of each slot until it transmits msg.1 / A to the gNB 20. At this time, the communication control unit 14 causes the UE communication unit 16 to transmit each SSB in the slot and symbol specified by the RRC parameters.

[0078] Furthermore, the communication control unit 14 acquires the reception timing of msg.1 / A by referring to the RACH config included in the SIB transmitted to the UE 30. Then, the communication control unit 14 notifies the UE communication unit 16 of the acquired reception timing of msg.1 / A, and causes the UE communication unit 16 to receive msg.1 / A transmitted from the UE 30.

[0079] When the transmission of msg.1 / A to gNB 20 is completed, communication control unit 14 receives DCI for beam ID notification via base station communication unit 11. Then, communication control unit 14 notifies UE communication unit 16 of the beam ID corresponding to each symbol for each slot notified by the DCI for beam ID notification, and instructs the beam to be used for each symbol for each slot.

[0080] The UE communication unit 16 receives notification from the communication control unit 14 of the beam ID corresponding to each symbol of each slot notified by the RRC parameters. Then, the UE communication unit 16 transmits a signal to the UE 30 using the beam to which the corresponding beam ID is assigned for each symbol in each slot. The UE communication unit 16 also receives notification from the communication control unit 14 of the SSBs notified by the RRC parameters and the slots and symbols to transmit each SSB. Then, the UE communication unit 16 transmits the SSB specified by the specified slot and symbol to the UE 30 using the specified beam.

[0081] Furthermore, the UE communication unit 16 receives notification of the reception timing of msg.1 / A from the communication control unit 14. Then, the UE communication unit 16 receives msg.1 / A transmitted from the UE 30 at the notified timing. Thereafter, the UE communication unit 16 outputs the received msg.1 / A to the transfer unit 15, which transfers it to the gNB 20 via the base station communication unit 11.

[0082] Fig. 8 is a flowchart of communication processing after establishment of initial connection by the wireless communication system according to the embodiment 2. Next, the flow of communication processing after establishment of initial connection by the wireless communication system 1 according to the embodiment will be described with reference to Fig. 8. In the following, the communication unit 25 of the gNB 20 communicates with the repeater 10 using the optimal beam between them.

[0083] The communication control unit 23 of the gNB 20 uses the optimal beam between it and the repeater 10 and transmits the SSB, beam ID, and various transmission timings to the repeater 10 using symbol ##0 of slot #n as RRC parameters (step S201). Here, the RRC parameters include the following information: Symbols ##0 and ##4-7 of slot #n+1 are the transmission timing of beam B0, and symbols #4-7 of slot #n+1 are the transmission timing of BBS#0. Furthermore, symbols ##1 and ##8-11 of slot #n+1 are the transmission timing of beam B1, and symbols #8-11 of slot #n+1 are the transmission timing of BBS#1. Furthermore, symbols ##0 and ##4-7 of slot #n+2 are the transmission timing of beam B2, and symbols #4-7 of symbol #n+2 are the transmission timing of BBS#2. Furthermore, symbols ##1 and ##8-11 of symbol #n+2 are the transmission timings of beam B3, and symbols #8-11 of symbol #n+2 are the transmission timings of BBS#3. The communication control unit 14 of the repeater 10 notifies the UE communication unit 16 of the repeater 10 of the SSB, beam ID, and various transmission timings notified by the RRC parameters.

[0084] Next, the communication control unit 23 of the gNB 20 transmits an SIB to the repeater 10 using DCI format 0 at symbol ##0 of slot #n+1 to perform scheduling (step S202). The communication control unit 14 of the repeater 10 references the received SIB and confirms that the reception timing of msg.1 / A for this signal is symbol ##0-1 of slot #n+3. The communication control unit 14 of the repeater 10 also confirms that msg.1 / A for this signal will be received by beam B0 corresponding to symbol ##0 of slot #n+1 specified by the RRC parameters. Then, the communication control unit 14 of the repeater 10 notifies the UE communication unit 16 that msg.1 / A for this signal will be received by beam B0 at symbol ##0-1 of slot #n+3.

[0085] The UE communication unit 16 of the repeater 10 performs scheduling by transmitting an SIB to the UE 30 at symbol ##0 of slot #n+1 using beam B0 notified by the RRC parameters (step S203).

[0086] Next, the communication control unit 23 of the gNB 20 transmits an SIB to the repeater 10 using DCI format 1 at symbol ##1 of slot #n+1 to perform scheduling (step S204). The communication control unit 14 of the repeater 10 references the received SIB and confirms that the reception timing of msg.1 / A for this signal is symbol ##2-3 of slot #n+3 and that it will be received by beam B1. The communication control unit 14 of the repeater 10 then notifies the UE communication unit 16 that msg.1 / A for this signal will be received at symbol ##2-3 of slot #n+3 by beam B1.

[0087] The UE communication unit 16 of the repeater 10 performs scheduling by transmitting an SIB to the UE 30 at symbol ##1 of slot #n+1 using beam B1 notified by the RRC parameters (step S205).

[0088] Next, the communication control unit 23 of the gNB 20 transmits SSB#0 to the repeater 10 in symbols ##4-7 of slot #n+1 (step S206).

[0089] The UE communication unit 16 of the repeater 10 transmits SSB#0 to the UE 30 using the beam B0 notified by the RRC parameters and symbols ##4-7 of slot #n+1 (step S207).

[0090] Next, the communication control unit 23 of the gNB 20 transmits SSB#1 to the repeater 10 in symbols ##8-11 of slot #n+1 (step S208).

[0091] The UE communication unit 16 of the repeater 10 transmits SSB#1 to the UE 30 using the beam B1 notified by the RRC parameters and symbols ##8-11 of slot #n+1 (step S209).

[0092] Next, the communication control unit 23 of the gNB 20 transmits an SIB to the repeater 10 using DCI format 0 at symbol ##0 of slot #n+2 to perform scheduling (step S210). The communication control unit 14 of the repeater 10 references the received SIB and confirms that the reception timing of msg.1 / A for this signal is symbols ##4-5 of slot #n+3 and that it will be received by beam B2. The communication control unit 14 of the repeater 10 then notifies the UE communication unit 16 that msg.1 / A for this signal will be received by beam B2 at symbols ##4-5 of slot #n+3.

[0093] The UE communication unit 16 of the repeater 10 performs scheduling by transmitting an SIB to the UE 30 at symbol ##0 of slot #n+2 using beam B2 notified by the RRC parameters (step S211).

[0094] Next, the communication control unit 23 of the gNB 20 transmits an SIB to the repeater 10 using DCI format 0 at symbol ##1 of slot #n+2 to perform scheduling (step S212). The communication control unit 14 of the repeater 10 references the received SIB and confirms that the reception timing of msg.1 / A for this signal is symbols ##6-7 of slot #n+3 and that it will be received by beam B3. The communication control unit 14 of the repeater 10 then notifies the UE communication unit 16 that msg.1 / A for this signal will be received by beam B3 at symbols ##6-7 of slot #n+3.

[0095] The UE communication unit 16 of the repeater 10 performs scheduling by transmitting an SIB to the UE 30 at symbol ##1 of slot #n+2 using beam B2 notified by the RRC parameters (step S213).

[0096] Next, the communication control unit 23 of the gNB 20 transmits SSB#2 to the repeater 10 in symbols ##4-7 of slot #n+2 (step S214).

[0097] The UE communication unit 16 of the repeater 10 transmits SSB#2 to the UE 30 using the beam B2 notified by the RRC parameters in symbols ##4-7 of slot #n+2 (step S215).

[0098] Next, the communication control unit 23 of the gNB 20 transmits SSB#3 to the repeater 10 in symbols ##8-11 of slot #n+2 (step S216).

[0099] The UE communication unit 16 of the repeater 10 transmits SSB#3 to the UE 30 using the beam B3 notified by the RRC parameters and symbols ##8-11 of slot #n+2 (step S217).

[0100] Next, the UE communication unit 16 of the repeater 10, in accordance with instructions from the communication control unit 23, receives msg.1 / A for communication using SSB#0 sent from UE 30 using beam B0 at symbol ##0-1 of slot #n+3 (step S218).

[0101] Next, the UE communication unit 16 of the repeater 10 transmits msg.1 / A for communication using SSB#0 to the gNB 20 using the optimal beam with symbols ##0-1 in slot #n+3 (step S219).

[0102] Next, the UE communication unit 16 of the repeater 10, in accordance with instructions from the communication control unit 23, receives msg.1 / A for communication using SSB#1 sent from UE 30 at symbol ##2-3 of slot #n+3 via beam B1 (step S220).

[0103] Next, the UE communication unit 16 of the repeater 10 transmits msg.1 / A for communication using SSB#1 to the gNB 20 using the optimal beam and symbols ##2-3 of slot #n+3 (step S221).

[0104] Next, the UE communication unit 16 of the repeater 10, in accordance with instructions from the communication control unit 23, receives msg.1 / A for communication using SSB#2 sent from UE 30 using beam B2 at symbols ##4-5 of slot #n+3 (step S222).

[0105] Next, the UE communication unit 16 of the repeater 10 transmits msg.1 / A for communication using SSB#2 to the gNB 20 using the optimal beam and symbols ##4-5 of slot #n+3 (step S223).

[0106] Next, the UE communication unit 16 of the repeater 10, in accordance with instructions from the communication control unit 23, receives msg.1 / A for communication using SSB#3 sent from UE 30 using beam B3 at symbols ##6-7 of slot #n+3 (step S224).

[0107] Next, the UE communication unit 16 of the repeater 10 transmits msg.1 / A for communication using SSB#3 to the gNB 20 using the optimal beam and symbols ##6-7 of slot #n+3 (step S225).

[0108] Thereafter, the communication control unit 23 of the gNB 20 transmits operation information for slots #n+4 to #n+12 at symbol ##0 of slot #n+4 to the repeater 10 via the communication unit 25 using the DCI for beam ID notification. The communication control unit 14 of the repeater 10 receives the DCI for beam ID notification at symbol ##0 of slot #n and acquires operation information for slots #n+1 to #n+9 (step S226). At this time, the operation information for slots #n+4 to #n+12 transmitted by the communication control unit 23 includes information such as, for example, that beam B0 is used at symbols ##1-4 of slot #n+4, beam B1 is used at symbols ##5-8 of slot #n+4, and beam B2 is used at symbols ##9-12 of slot #n+4.

[0109] Next, in symbol ##1 of slot #n+4, the communication control unit 23 of the gNB 20 transmits a signal in DCI format 0 to the repeater 10 (step S227).

[0110] Since the signal has been transmitted at symbol ##1 of slot #n+4, the communication control unit 23 of the repeater 10 determines that beam B0 should be used and instructs the UE communication unit 16 to use beam B0 when transmitting the signal at symbol ##1 of slot #n+4 to the UE 30. The transfer unit 15 of the repeater 10 outputs the signal of DCI format 0 received via the base station communication unit 11 to the UE communication unit 16 so as to transmit it at symbol ##1 of slot #n+4. Then, in accordance with the instruction from the communication control unit 23, the UE communication unit 16 transmits the signal of DCI format 0 to the UE 30 at symbol ##1 of slot #n+4 using beam B0 (step S228).

[0111] Next, at symbol ##2-4 of slot #n+4, the communication control unit 23 of the gNB 20 uses DCI to transmit msg.2 / A for communication using DDB#0 to the repeater 10 (step S229).

[0112] Since the signal has been transmitted using symbols ##2-4 of slot #n+4, the communication control unit 23 determines that beam B0 should be used and instructs the UE communication unit 16 to use beam B0 when transmitting the signal using symbols ##4-7 of slot #n+4 to the UE 30. The forwarding unit 15 outputs msg.2 / A for communication using DDB#0 received via the base station communication unit 11 to the UE communication unit 16 so that it is transmitted using symbols ##2-4 of slot #n+4. In accordance with the instruction from the communication control unit 23, the UE communication unit 16 transmits msg.2 / A for communication using DDB#0 using beam B0 at symbols ##2-4 of slot #n+4 to the UE 30 (step S230).

[0113] Next, at symbol ##5 of slot #n+4, the communication control unit 23 of the gNB 20 transmits a signal in DCI format 0 to the repeater 10 (step S231).

[0114] Because the signal has been transmitted at symbol ##5 of slot #n+4, the communication control unit 23 determines that beam B1 should be used and instructs the UE communication unit 16 to use beam B1 when transmitting the signal at symbol ##5 of slot #n+4 to UE 30. The transfer unit 15 outputs to the UE communication unit 16 to transmit the signal of DCI format 0 received via the base station communication unit 11 at symbol ##5 of slot #n+4. In accordance with the instruction from the communication control unit 23, the UE communication unit 16 of the repeater 10 transmits the signal of DCI format 0 to UE 30 at symbol ##5 of slot #n+4 using beam B1 (step S232).

[0115] Next, in symbols ##6-8 of slot #n+4, the communication control unit 23 of the gNB 20 uses DCI to transmit msg.2 / A for communication using DDB#1 to the repeater 10 (step S233).

[0116] Since the signal has been transmitted at symbols ##6-8 of slot #n+4, the communication control unit 23 determines that beam B1 should be used and instructs the UE communication unit 16 to use beam B1 when transmitting the signal at symbols ##6-8 of slot #n+4 to the UE 30. The forwarding unit 15 outputs msg.2 / A for communication using DDB#1 received via the base station communication unit 11 to the UE communication unit 16 so that it is transmitted at symbols ##6-8 of slot #n+4. The UE communication unit 16 of the repeater 10, in accordance with the instruction from the communication control unit 23, transmits msg.2 / A for communication using DDB#1 to the UE 30 at symbols ##6-8 of slot #n+4 using beam B1 (step S234).

[0117] Next, at symbol ##9 of slot #n+4, the communication control unit 23 of the gNB 20 transmits a signal in DCI format 0 to the repeater 10 (step S235).

[0118] Because the signal has been transmitted at symbol ##9 of slot #n+4, the communication control unit 23 determines that beam B2 should be used and instructs the UE communication unit 16 to use beam B2 when transmitting the signal at symbol ##9 of slot #n+4 to UE 30. The transfer unit 15 outputs to the UE communication unit 16 the signal of DCI format 0 received via the base station communication unit 11, so as to transmit it at symbol ##9 of slot #n+4. In accordance with the instruction from the communication control unit 23, the UE communication unit 16 of the repeater 10 transmits the signal of DCI format 0 to UE 30 at symbol ##9 of slot #n+4 using beam B2 (step S236).

[0119] Next, at symbols ##10-12 of slot #n+4, the communication control unit 23 of the gNB 20 uses DCI to transmit msg.2 / A for communication using DDB#2 to the repeater 10 (step S237).

[0120] Since the signal has been transmitted at symbols ##10-12 of slot #n+4, the communication control unit 23 determines that beam B2 should be used and instructs the UE communication unit 16 to use beam B2 when transmitting the signal at symbols ##10-12 of slot #n+4 to the UE 30. The forwarding unit 15 outputs msg.2 / A for communication using DDB#2 received via the base station communication unit 11 to the UE communication unit 16 so that it is transmitted at symbols ##10-12 of slot #n+4. In accordance with the instruction from the communication control unit 23, the UE communication unit 16 transmits msg.2 / A for communication using DDB#2 to the UE 30 at symbols ##10-12 of slot #n+4 using beam B2 (step S238).

[0121] From slot #n+5 onwards, repeater 10 continues to transmit the signal transmitted from gNB 20 to UE 30 using the beam specified in the DCI for beam ID notification.

[0122] As described above, in the wireless communication system according to this embodiment, the base station controls the repeater using the RRC parameters until it receives msg.1 / A, and then controls the repeater using DCI. The base station device periodically broadcasts the RRC parameters, which enables it to periodically transmit SSBs. Furthermore, by transmitting the RRC parameters, it is not necessary to transmit DCI for beam ID notification until it receives msg.1 / A, thereby reducing the overhead caused by DCI transmission. [Example]

[0123] Next, a third embodiment will be described. The wireless communication system 1 according to this embodiment differs from the first embodiment in that the repeater 10 spontaneously transmits different SSBs with different beams at different timings. The wireless communication system 1 according to this embodiment is also represented by the block diagram of Fig. 2. In the following description, the operation of each unit similar to that of the first embodiment will be omitted.

[0124] After establishing the initial connection, the communication control unit 23 of the gNB 20 determines the number of SSBs to be used and SSB indices, which are identifiers for each SSB, from the performance information of the repeater 10. Then, the communication control unit 23 notifies the communication control unit 14 of the repeater 10 of the SSB indices for the SSBs to be used. Thereafter, the communication control unit 23 of the gNB 20 establishes a connection for data communication in the same manner as for normal UE communication.

[0125] However, if the gNB 20 directly specifies the beam to be transmitted in subsequent communications, the communication control unit 23 of the gNB 20 transmits a DCI for beam ID notification to the repeater 10 and causes the repeater 10 to transmit a signal to the UE 30 using a beam having the specified beam ID. For example, the communication control unit 23 of the gNB 20 may cause the repeater 10 to autonomously perform beam control until msg.1 / A is received, and thereafter directly specify the beam and transmit the signal.

[0126] Here, the format of the DCI for beam ID notification used in this embodiment can also be the format shown in Fig. 3. However, in the case of the format shown in Fig. 4, the scheduling related to SSB and msg.1 / A overlaps with the scheduling notified by the RRI parameters, so the use of the format shown in Fig. 4 is not suitable for the wireless communication system 1 according to this embodiment.

[0127] After establishing the RRC connection, the communication control unit 14 of the repeater 10 receives communication setting information for receiving DCI and the SSB indexes of each of the multiple SSBs to be used from the gNB 20 via the base station communication unit 11.

[0128] Thereafter, the communication control unit 14 receives the SIB from the communication control unit 20 of the gNB 20. Next, the communication control unit 14 selects one of a plurality of beams that can be used for beamforming. Then, the communication control unit 14 transmits the received SIB to the UE 30 using the selected beam.

[0129] Next, the communication control unit 14 receives the SSB from the communication control unit 20 of the gNB 20. Next, the communication control unit 14 identifies the SSB index of the acquired SSB. Then, the communication control unit 14 transmits the acquired SSB to the UE 30 using the beam that transmitted the SIB corresponding to the acquired SSB. Thereafter, the communication control unit 14 associates the SSB index with the beam and determines the beam to be used for subsequent communications using that SSB. That is, when performing communications using that SSB, the communication control unit 14 transmits a signal to the UE 30 using the determined beam. The communication control unit 14 performs the above processing for all communications using SSB.

[0130] However, when the gNB 20 directly specifies the beam to be transmitted in subsequent communications, the communication control unit 14 receives a DCI for beam ID notification from the communication control unit 23 of the gNB 20. Then, the communication control unit 14 notifies the UE communication unit 16 of the beam ID specified in the DCI for beam ID notification for each symbol in each slot. The UE communication unit 16 transmits a signal to the repeater 10 and the UE 30 using a beam having the notified beam ID in each symbol in each slot.

[0131] Fig. 9 is a flowchart of the initial connection between a gNB and a repeater according to embodiment 3. Next, the flow of the initial connection between the gNB 20 and the repeater 10 according to this embodiment will be described with reference to Fig. 9.

[0132] The RRC connection implementation unit 21 of the gNB 20 and the RRC connection implementation unit 12 of the repeater 10 execute an initial connection procedure to establish an RRC connection (step S301).

[0133] After the RRC connection is established, the performance information notification unit 13 of the repeater 10 transmits performance information of the repeater 10, including the presence or absence of a repeater function and the number of beams that can be transmitted and received, to the gNB 20 (step S302).

[0134] Next, the communication setting information transmitter 22 of the gNB 20 receives a notification of the completion of the RRC connection from the RRC connection implementation unit 21. Then, the communication setting information transmitter 22 of the gNB 20 transmits communication setting information for receiving DCI, including information on the frequency resource for transmitting the DCI, to the communication control unit 14 of the repeater 10 (step S303).

[0135] Next, the communication control unit 23 of the gNB 20 determines the number of SSBs to be used and their respective SSB indices from the performance information of the repeater 10. Next, the communication control unit 23 of the gNB 20 transmits the SSB indices of the SSBs to be used to the communication control unit 14 of the repeater 10 (step S304).

[0136] Fig. 10 is a flowchart of communication processing after establishment of an initial connection by a wireless communication system according to Example 3. Next, the flow of communication processing after establishment of an initial connection by a wireless communication system 1 according to this example will be described with reference to Fig. 10. Here, a case will be described in which a beam to be transmitted from the gNB 20 side is directly designated from slot #n+4 after receiving msg.1 / A.

[0137] The communication control unit 23 of the gNB 20 performs scheduling by transmitting the SIB to the repeater 10 using the optimal beam between the repeater 10 and the communication unit 25 at symbol ##0 of slot #n (step S311).

[0138] The communication control unit 14 of the repeater 10 receives the SIB via the base station communication unit 11. Next, the communication control unit 14 selects a beam B0 from among beams that can be beamformed. Then, the communication control unit 14 transmits the SIB to the UE 30 using the selected beam B0 via the UE communication unit 16 at symbol ##0 of slot #n to perform scheduling (step S312).

[0139] Next, the communication control unit 23 of the gNB 20 transmits the SIB to the repeater 10 using the optimal beam between the repeater 10 via the communication unit 25 at symbol ##1 of slot #n, and performs scheduling (step S313).

[0140] The communication control unit 14 of the repeater 10 receives the SIB via the base station communication unit 11. Next, the communication control unit 14 selects a beam B1 from among beams that can be beamformed. Then, the communication control unit 14 transmits the SIB to the UE 30 using the selected beam B1 via the UE communication unit 16 to perform scheduling (step S314).

[0141] Next, the communication control unit 23 of the gNB 20 transmits SSB#0 to the repeater 10 in symbols ##4-7 of slot #n via the communication unit 25 using the optimal beam between the repeater 10 (step S315).

[0142] The communication control unit 14 of the repeater 10 receives SSB#0 at symbols ##4-7 of slot #n via the base station communication unit 11 in accordance with the scheduling of the SIB received at symbol ##0 of slot #n. Next, the communication control unit 14 transmits SSB#0 to the UE 30 at symbols ##4-7 of slot #n via the UE communication unit 16 using beam B0 that was used to transmit the SIB received at symbol ##0 of slot #n (step S316). Then, the communication control unit 14 associates the SSB index of SSB#0 with beam B0 and determines to use beam B0 in communications using SSB#0.

[0143] Next, the communication control unit 23 of the gNB 20 transmits SSB#1 to the repeater 10 in symbols ##8-11 of slot #n via the communication unit 25 using the optimal beam between the repeater 10 (step S317).

[0144] The communication control unit 14 of the repeater 10 receives SSB#1 at symbols ##8-11 of slot #n via the base station communication unit 11 in accordance with the scheduling of the SIB received at symbol ##1 of slot #n. Next, the communication control unit 14 transmits SSB#1 to the UE 30 at symbols ##8-11 of slot #n via the UE communication unit 16 using beam B0, which was used to transmit the SIB received at symbol ##0 of slot #n (step S318). Then, the communication control unit 14 associates the SSB index of SSB#1 with beam B1, and determines to use beam B1 in communications using SSB#1.

[0145] Thereafter, the communication control unit 14 of the repeater 10 transmits a signal to the UE 30 using beam B0 when communicating using SSB#0, and transmits a signal to the UE 30 using beam B1 when communicating using SSB#1.

[0146] Thereafter, at symbol ##0 of slot #n+4 after receiving msg.1 / A, the communication control unit 23 of the gNB 20 transmits operation information for slots #n+4 to #n+12 to the repeater 10 via the communication unit 25 using DCI for beam ID notification. The communication control unit 14 of the repeater 10 receives the DCI for beam ID notification at symbol ##0 of slot #n and acquires operation information for slots #n+1 to #n+9 (step S319). At this time, the operation information for slots #n+1 to #n+9 transmitted by the communication control unit 23 includes information such as, for example, that beam B0 is used at symbols ##1-4 of slot #n+4 and beam B1 is used at symbols ##5-8 of slot #n+4.

[0147] Next, in symbol ##1 of slot #n+4, the communication control unit 23 of the gNB 20 transmits a signal in DCI format 0 to the repeater 10 (step S320).

[0148] Since the signal has been transmitted at symbol ##1 of slot #n+4, the communication control unit 23 of the repeater 10 determines that beam B0 should be used and instructs the UE communication unit 16 to use beam B0 when transmitting the signal at symbol ##1 of slot #n+4 to the UE 30. The transfer unit 15 of the repeater 10 outputs the signal of DCI format 0 received via the base station communication unit 11 to the UE communication unit 16 so as to transmit it at symbol ##1 of slot #n+4. Then, in accordance with the instruction from the communication control unit 23, the UE communication unit 16 transmits the signal of DCI format 0 to the UE 30 at symbol ##1 of slot #n+4 using beam B0 (step S321).

[0149] Next, at symbol ##2-4 of slot #n+4, the communication control unit 23 of the gNB 20 uses DCI to transmit msg.2 / A for communication using DDB#0 to the repeater 10 (step S322).

[0150] Since the signal has been transmitted at symbols ##4-7 of slot #n+4, the communication control unit 23 determines that beam B0 should be used and instructs the UE communication unit 16 to use beam B0 when transmitting the signal at symbols ##4-7 of slot #n+4 to the UE 30. The transfer unit 15 outputs msg.2 / A for communication using DDB#0 received via the base station communication unit 11 to the UE communication unit 16 so that it is transmitted at symbols ##4-7 of slot #n+4. The UE communication unit 16 of the repeater 10, in accordance with the instruction from the communication control unit 23, transmits msg.2 / A for communication using DDB#0 to the UE 30 at symbols ##4-7 of slot #n+4 using beam B0 (step S323).

[0151] Next, at symbol ##5 of slot #n+4, the communication control unit 23 of the gNB 20 transmits a signal in DCI format 0 to the repeater 10 (step S324).

[0152] Because the signal has been transmitted at symbol ##5 of slot #n+4, the communication control unit 23 determines that beam B1 should be used and instructs the UE communication unit 16 to use beam B1 when transmitting the signal at symbol ##5 of slot #n+4 to UE 30. The transfer unit 15 outputs the signal of DCI format 0 received via the base station communication unit 11 to the UE communication unit 16 so as to transmit it at symbol ##5 of slot #n+4. In accordance with the instruction from the communication control unit 23, the UE communication unit 16 of the repeater 10 transmits the signal of DCI format 0 to UE 30 at symbol ##5 of slot #n+4 using beam B1 (step S325).

[0153] Next, in symbols ##6-8 of slot #n+4, the communication control unit 23 of the gNB 20 uses DCI to transmit msg.2 / A for communication using DDB#1 to the repeater 10 (step S326).

[0154] Since the signal has been transmitted at symbols ##6-8 of slot #n+4, the communication control unit 23 determines that beam B1 should be used and instructs the UE communication unit 16 to use beam B1 when transmitting the signal at symbols ##6-8 of slot #n+4 to the UE 30. The forwarding unit 15 outputs msg.2 / A for communication using DDB#1 received via the base station communication unit 11 to the UE communication unit 16 so that it is transmitted at symbols ##6-8 of slot #n+4. In accordance with the instruction from the communication control unit 23, the UE communication unit 16 of the repeater 10 transmits msg.2 / A for communication using DDB#1 to the UE 30 at symbols ##6-8 of slot #n+4 using beam B1 (step S327).

[0155] Thereafter, the repeater 10 continues to transmit the signal transmitted from the gNB 20 to the UE 30 using the beam specified in the DCI for beam ID notification.

[0156] As described above, in the wireless communication system according to this embodiment, the repeater autonomously determines a beam corresponding to the SSB and communicates with the UE without receiving control from the gNB using DCI or RRC parameters. As a result, the gNB only needs to notify the repeater of the SSB index in order to relay the SSB signal. Therefore, it is possible to reduce the overhead of control signals. [Example]

[0157] Next, a fourth embodiment will be described. The wireless communication system 1 according to this embodiment differs from the first embodiment in that the operation of the repeater 10 is turned off for symbols for which the beam to be used is not scheduled. The wireless communication system 1 according to this embodiment is also represented by the block diagram of Fig. 2. In the following description, the description of the operation of each unit similar to that of the first embodiment will be omitted.

[0158] The communication control unit 14 of the repeater 10 receives the DCI for beam ID notification from the communication control unit 23 of the gNB 20. Then, the communication control unit 14 refers to the DCI for beam ID notification to confirm the beam ID to be used for each symbol for each slot. Then, the communication control unit 14 notifies the UE communication unit 16 of the beam ID for each symbol for each slot.

[0159] Thereafter, the communication control unit 14 turns off the operation of the repeater 10 for symbols in which the beam ID of the beam to be used in each slot is not specified in the DCI for beam ID notification. Here, turning off the operation of the repeater 10 may mean completely turning off the power of the repeater 10, or may mean putting the repeater 10 into a power-saving mode in which communication can be immediately performed, taking into account the delay until communication starts.

[0160] The UE communication unit 16 transmits a signal to the repeater 10 and the UE 30 using a beam having the notified beam ID in each symbol of each slot.

[0161] 11 is a flowchart of a communication process after the establishment of an initial connection by the wireless communication system according to the embodiment 4. Next, the flow of the communication process after the establishment of an initial connection by the wireless communication system 1 according to the embodiment will be described with reference to FIG.

[0162] The communication control unit 23 of the gNB 20 transmits operation information for slots #n+1 to #n+9 to the repeater 10 via the communication unit 25 at symbol ##0 of slot #n using DCI for beam ID notification. The communication control unit 14 of the repeater 10 receives the DCI for beam ID notification at symbol ##0 of slot #n and acquires the operation information for slots #n+1 to #n+9 (step S401). At this time, the operation information for slots #n+1 to #n+9 transmitted by the communication control unit 23 includes information such as using beam B0 at symbol ##0 of slot #n+1 and using beam B1 at symbol ##1 of slot #n+1. Furthermore, the operation information for slots #n+1 to #n+9 includes information such as using beam B0 at symbols ##4-7 of slot #n+1 and using beam B1 at symbols ##8-11 of slot #n+1.

[0163] Next, at symbol ##0 of slot #n+1, the communication control unit 23 of the gNB 20 transmits SI to the repeater 10 using DCI format 0 (step S402).

[0164] Since the signal has been transmitted at symbol ##0 of slot #n+1, the communication control unit 23 of the repeater 10 determines that beam B0 should be used and instructs the UE communication unit 16 to use beam B0 when transmitting the signal at symbol ##0 of slot #n+1 to the UE 30. The transfer unit 15 of the repeater 10 outputs the SIB received via the base station communication unit 11 to the UE communication unit 16 so that it is transmitted at symbol ##0 of slot #n+1. Then, in accordance with the instruction from the communication control unit 23, the UE communication unit 16 transmits the SIB to the UE 30 using beam B0 at symbol ##0 of slot #n+1, thereby performing scheduling (step S403).

[0165] Next, at symbol ##1 of slot #n+1, the communication control unit 23 of the gNB 20 transmits the SIB to the repeater 10 using DCI format 0 (step S404).

[0166] Since the signal has been transmitted at symbol ##1 of slot #n+1, the communication control unit 23 of the repeater 10 determines that beam B1 should be used and instructs the UE communication unit 16 to use beam B1 when transmitting the signal at symbol ##1 of slot #n+1 to the UE 30. The transfer unit 15 of the repeater 10 outputs the SIB received via the base station communication unit 11 to the UE communication unit 16 so that it is transmitted at symbol ##1 of slot #n+1. Then, in accordance with the instruction from the communication control unit 23, the UE communication unit 16 transmits the SIB to the UE 30 using beam B1 at symbol ##1 of slot #n+1, thereby performing scheduling (step S405).

[0167] Next, in symbols ##4-7 of slot #n+1, the communication control unit 23 of the gNB 20 transmits SSB #0 to the repeater 10 using DCI (step S406).

[0168] Since the signal was transmitted using symbols ##4-7 of slot #n+1, the communication control unit 23 determines that beam B0 should be used and instructs the UE communication unit 16 to use beam B0 when transmitting the signal using symbols ##4-7 of slot #n+1 to UE 30. The transfer unit 15 outputs the SSB#0 received via the base station communication unit 11 to the UE communication unit 16 so that it is transmitted using symbols ##4-7 of slot #n+1. In accordance with the instruction from the communication control unit 23, the UE communication unit 16 of the repeater 10 transmits SSB#0 to UE 30 using beam B0 using symbols ##4-7 of slot #n+1 (step S407).

[0169] Next, in symbols ##8-11 of slot #n+1, the communication control unit 23 of the gNB 20 transmits SSB#1 to the repeater 10 using DCI (step S408).

[0170] Since the signal was transmitted at symbols ##8-11 of slot #n+1, the communication control unit 23 determines that beam B1 should be used and instructs the UE communication unit 16 to use beam B1 when transmitting the signal at symbols ##8-11 of slot #n+1 to UE 30. The transfer unit 15 outputs SSB#1 received via the base station communication unit 11 to the UE communication unit 16 so that it is transmitted at symbols ##8-11 of slot #n+1. In accordance with the instruction from the communication control unit 23, the UE communication unit 16 of the repeater 10 transmits SSB#1 to UE 30 using beam B1 at symbols ##8-11 of slot #n+1 (step S409).

[0171] Since the beam ID of the beam to be used is not specified in the symbol of the subsequent slot #n+1, the communication control unit 14 of the repeater 10 turns off the repeater 10 (step S410).

[0172] Thereafter, the communication control unit 14 repeats the following for each slot: when a symbol with a designated beam ID is reached, the repeater 10 is turned on to resume communication; when a symbol with no designated beam ID is reached, the repeater 10 is turned off.

[0173] Here, in this embodiment, we have described a case where a function to turn off repeater 10 with a symbol that does not specify a beam ID is added to the communication system of embodiment 1, but this function can also be added to embodiment 2 or 3.

[0174] As described above, in the wireless communication system according to this embodiment, the repeater is turned off by a symbol that does not specify a beam ID. This allows the repeater to be turned off when not needed, thereby suppressing increases in power consumption and noise. Furthermore, since the repeater can be turned on and off by a symbol schedule without sending on / off control information, it can be realized with a simple configuration without increasing the overhead of control signals. [Example]

[0175] Next, a fifth embodiment will be described. In the wireless communication system 1 according to this embodiment, when an unused beam ID is specified, the repeater 10 is turned off. The wireless communication system 1 according to this embodiment is also represented by the block diagram of Fig. 2. In the following description, the operation of each unit similar to that of the first embodiment will be omitted.

[0176] For example, a case will be described in which the maximum number of beams of the repeater 10 is 8 and beams B1 to B8 are used as beam IDs.

[0177] The communication control unit 14 of the repeater 10 receives the DCI for beam ID notification from the communication control unit 23 of the gNB 20. Then, the communication control unit 14 refers to the DCI for beam ID notification to confirm the beam ID to be used for each symbol for each slot. Here, if beams B1 to B8 are specified as the beam ID, the communication control unit 14 notifies the UE communication unit 16 of the beam ID for each symbol for each slot.

[0178] On the other hand, if a beam ID other than beams B1 to B8 is specified in the DCI for beam DI notification, for example, if beam B12 is specified, the communication control unit 14 turns off the repeater 10. Thereafter, if a predetermined condition is satisfied, the communication control unit 14 turns on the repeater 10. For example, the base station communication unit 11 receives DCI, and when DCI for beam ID notification is received, if beams B1 to B8 are specified in each symbol for each slot, the communication control unit 14 turns on the repeater 10.

[0179] As described above, in the wireless communication device according to this embodiment, the repeater is turned off when an unused beam ID is specified. This allows the repeater to be turned off when not needed, thereby suppressing increases in power consumption and noise. [Example]

[0180] In the above embodiments, the repeater 10 communicates with the UE 30 using different beams with different timings for transmitting SSBs, but the signals handled are not limited to this. For example, the functions described in the above embodiments can also be applied to transmitting CSI-RS and PDSCH / PDCCH. The beam for transmitting CSI-RS (Channel State Information-Reference Signal) and PDSCH (Physical Downlink Shared Channel) / PDCCH (Physical Downlink Control Channel) may be the same beam as the beam for transmitting SSBs, or may be a narrowband beam.

[0181] Fig. 12 is a diagram for explaining the operation when different beams at different timings are used to transmit multiple CSI-RSs. Next, with reference to Fig. 12, the operation when different beams at different timings are used to transmit multiple CSI-RSs will be described.

[0182] In Figure 12, the signal control unit 23 of gNB20 transmits CSI-RS#C1, CSI-RS#C2, CSI-RS#C3-#8, CSI-RS#C9, and CSI-RS#C10 using different beams.

[0183] In more detail, the communication control unit 23 transmits DCI for beam ID notification to the repeater 10 using the optimal beam between the repeater 10 and specifies the beam ID of the beam to be used in each symbol for each slot. Then, the signal control unit 23 transmits each of the CSI-RS#C3-#C8 to the repeater 10 by TDM transmission using the optimal beam between the repeater 10 and the repeater 10. At this time, the signal control unit 23 transmits CSI-RS#C3 to #C8 in symbols for each slot, each of which uses a different beam.

[0184] The communication control unit 14 of the repeater 10 receives DCI for beam ID notification from the communication control unit 20 of the gNB 20 via the base station communication unit 11. Then, the communication control unit 14 checks the beam ID of the beam used in each symbol for each slot.

[0185] Thereafter, when the base station communication unit 11 receives CSI-RS#C3 from the communication control unit 20 of the gNB 20, the communication control unit 14 notifies the UE communication unit 16 of the beam ID of the beam to be used in the received slot and signal. Similarly, when the base station communication unit 11 receives each of CSI-RS#C4-C8 from the communication control unit 20 of the gNB 20, the communication control unit 14 notifies the UE communication unit 16 of the beam ID of the beam to be used in the received slot and packet, respectively.

[0186] The UE communication unit 16 receives notification of the beam ID of the beam used in the slot and signal in which CSI-RS#C3 was received from the UE communication unit 16. Then, the UE communication unit 16 transmits CSI-RS#C3 to the UE 30 in the received slot and signal using the specified beam ID. For example, as shown in Fig. 12, the UE communication unit 16 transmits CSI-RS#C3 to the UE 30 using beam 201.

[0187] Similarly, the UE communication unit 16 receives from the UE communication unit 16 notification of the beam IDs of the beams used in the slots and signals in which CSI-RS#C4 to #C8 are received, respectively. Then, the UE communication unit 16 transmits CSI-RS#C4 to #C8 to the UE 30 in the received slots and signals using the designated beam IDs. For example, as shown in Fig. 12, the UE communication unit 16 transmits CSI-RS#C5 to the UE 30 using beam 202, and transmits CSI-RS#C8 to the UE 30 using beam 203.

[0188] As described above, in the wireless communication system according to this embodiment, the repeater transmits different CSI-RSs to the UE at different times using different beams. This allows the UE to acquire the received CSI-RS strength of each beam, and the base station device can select the optimal beam between the repeater and the UE. This allows for appropriate coverage expansion and efficient communication. [Explanation of symbols]

[0189] 1. Wireless communication systems 10 Repeater 11 Base station communication unit 12 Initial connection implementation unit 13 Performance information notification section 14 Communication control section 15 Transfer Unit 16 UE Communications Department 20 gNB 21 Initial Connection Execution Department 22 Communication setting information transmission unit 23 Communication control section 24 Data transmission and reception unit 25 Communications Department 30UE

Claims

1. a first communication unit that receives a plurality of signals from a first wireless communication device; a communication control unit that assigns a transmission timing and a beam to be used for wireless communication corresponding to each of the plurality of signals received by the first communication unit; a second communication unit that transmits each of the plurality of signals to a second wireless communication device at the transmission timing assigned by the communication control unit using the beam assigned by the communication control unit, The communication control unit receives downlink control information including first information including a beam index indicating the beam and information on the transmission timing assigned to each of the plurality of signals. A relay device characterized by:

2. 2. The relay device according to claim 1, wherein the first communication unit receives each of the plurality of signals in a time division multiplexing system.

3. 2. The relay device according to claim 1, wherein the communication control unit receives the first information as a parameter for establishing a connection for controlling wireless resources with the first wireless communication device.

4. 2. The relay device according to claim 1, wherein the communication control unit stops a predetermined operation of the relay device at a timing that is not assigned as the transmission timing to any of the plurality of signals in the first information.

5. The relay device according to claim 1 , characterized in that the communication control unit stops a predetermined operation of the relay device when the first information includes a predetermined beam index.

6. The relay device described in claim 1, characterized in that the communication control unit receives the beam index for each of the beams from the first wireless communication device, selects the beam to be assigned to each of the multiple signals, and causes the second communication unit to communicate using the beam index of the selected beam.

7. a communication unit that transmits a plurality of signals to the relay device; a communication control unit that transmits downlink control information to the relay device, the downlink control information including first information including a beam index indicating a transmission timing corresponding to each of the plurality of signals and a beam used for wireless communication, and information on the transmission timing assigned to each of the plurality of signals, and causes the relay device to transmit each of the plurality of signals to a second wireless communication device at the transmission timing using the beam indicated by the beam index; A base station device comprising:

8. a first wireless communication device that transmits a plurality of signals; receiving the plurality of signals from the first wireless communication device; assigning a transmission timing and a beam to be used for wireless communication corresponding to each of the plurality of signals; transmitting each of the plurality of signals to a second wireless communication device using the beam at the transmission timing; a relay device that receives downlink control information including first information that includes a beam index indicating the beam and information on the transmission timing assigned to each of the plurality of signals; A wireless communication system comprising:

Images