Wireless communication system, relay station, and relay method

Abstract

This wireless communication system comprises a base station that transmits / receives signals to / from terminals, and a relay station that relays the signals between the base station and the terminals. The base station comprises a scheduling function unit that determines a schedule for the transmission / reception of the signals to / from a plurality of terminals 20, and that transmits schedule information indicating the determined schedule to the relay station. The relay station comprises a schedule information acquiring unit that acquires the schedule information from the base station, and a beam control unit that identifies a terminal as a transmission destination on the basis of the schedule information, and that controls the beam that is used for the relaying for each terminal identified as the transmission destination, on the basis of a beam number that is specified in advance for each terminal.

Description

[Technical Field]

[0001] The present invention relates to a wireless communication system, a relay station, and a relay method. [Background technology]

[0002] In wireless communication, improvements to the quality of relay stations that relay communications between base stations and terminals are being studied. For example, Non-Patent Document 1 discloses a technology in which a wireless device with a relay function is mounted on a mobile object (such as a forklift) that travels around a factory or the like, and the device is turned on and off as needed. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Daisuke Murayama et al., A Study on Flexible Utilization of High Frequency Bands in Closed Environments with High Density of Obstacles, IEICE 2022 General Conference B-5-27 Summary of the Invention [Problem to be solved by the invention]

[0004] A relay station in a wireless communication network may cause radio interference because it relays and retransmits signals that do not require relaying. However, no method has been proposed to reduce radio interference caused by signals transmitted by relay stations.

[0005] The disclosed technology aims to reduce radio interference caused by signals transmitted by relay stations in a wireless communication network. [Means for solving the problem]

[0006] The disclosed technology is a wireless communication system comprising a base station for transmitting and receiving signals to and from terminals, and a relay station for relaying signals between the base station and the terminals, wherein the base station comprises a scheduling function unit that determines a schedule for transmitting and receiving signals to a plurality of terminals and transmits schedule information indicating the determined schedule to the relay station, and the relay station comprises a schedule information acquisition unit that acquires the schedule information from the base station, and a beam control unit that identifies a destination terminal based on the schedule information and controls a beam to be used for relaying for each terminal identified as a destination based on a beam number that is predefined for each terminal; the relay station further includes a relay function control unit that controls whether to enable a function of relaying a signal between the base station and the terminal based on the schedule information. It is a wireless communication system. [Effects of the Invention]

[0007] It is possible to reduce radio interference caused by signals transmitted by relay stations in a wireless communication network. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating an example of a configuration of a wireless communication system according to an embodiment of the present invention. [Figure 2] 1 is a diagram illustrating an example of a functional configuration of a base station and a relay station included in a wireless communication system according to an embodiment of the present invention. [Figure 3] 10 is a flowchart illustrating an example of a flow of a relay process according to an embodiment of the present invention. [Figure 4] FIG. 2 illustrates an example of a hardware configuration of a computer. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present invention (the present embodiment) will be described with reference to the drawings. The embodiment described below is merely an example, and the embodiment to which the present invention is applied is not limited to the following embodiment.

[0010] <Outline of this embodiment> In this embodiment, an example will be described in which a relay station relays a signal using a beam controlled for each terminal based on a beam number acquired in advance for each terminal.

[0011] <Overall Configuration of the Present Embodiment> 1 is a diagram showing an example of the configuration of a wireless communication system according to an embodiment of the present invention. Wireless communication system 1 includes relay station 10, terminal 20, base station 30, and core network 40. Base station 30 and core network 40 are connected to each other so that they can communicate with each other via a wired or wireless communication method.

[0012] Relay station 10 is a device that relays signals in communications between base station 30 and multiple terminals 20. Relay station 10 receives information indicating a schedule for signal transmission and reception (hereinafter, schedule information) from base station 30, selects a beam for each terminal 20 based on the schedule information, and relays signals using the selected beam.

[0013] The base station 30 receives information necessary for control from the core network 40, and transmits and receives signals to and from the terminal 20 via the relay station 10. The base station 30 transmits schedule information to the relay station 10 (or the terminal 20).

[0014] The terminal 20 is, for example, a mobile station, and transmits and receives signals to and from the base station 30 via the relay station 10 .

[0015] <Functional configuration of base station and relay station> 2 is a diagram showing an example of the functional configuration of a base station and a relay station included in a wireless communication system according to an embodiment of the present invention.

[0016] The scheduling function unit 31 determines a schedule for transmitting and receiving signals to and from multiple terminals 20, and transmits schedule information indicating the determined schedule to the relay station 10. The schedule information may include, for example, a terminal ID for identifying each terminal, allocated transmission resources (frequencies and time slots (resource blocks)), etc.

[0017] Furthermore, relay station 10 includes schedule information acquisition unit 11, relay function control unit 12, and beam control unit 13. Schedule information acquisition unit 11 receives schedule information from base station 30 via wireless communication. For example, the schedule information may be included in a PDCCH (Physical Downlink Control Channel) transmitted to terminal 20 or relay station 10. That is, schedule information acquisition unit 11 may receive the PDCCH and acquire the schedule information by decoding the received PDCCH.

[0018] Relay function control unit 12 controls the relay function for relaying signals between base station 30 and terminal 20. For example, relay function control unit 12 may identify, based on schedule information, either or both of the time resources and frequency resources of signals that relay station 10 itself relays and that are transmitted to or received from terminal 20, and turn on (enable) the relay function only when either or both of the identified time resources and frequency resources are used.

[0019] The beam control unit 13 controls the beam to be used when transmitting a signal to each terminal 20. Specifically, the beam control unit 13 may identify the destination terminal 20 based on the schedule information, and determine the beam to be used for each terminal 20 identified as the destination based on a beam number predefined for each terminal 20.

[0020] <Operation According to the Present Embodiment> Next, the operation of relay station 10 will be described with reference to the drawings. Relay station 10 controls relay operation in accordance with scheduling by base station 30, so it needs to be synchronized with base station 30 and terminal 20 in advance. For synchronization between relay station 10 and base station 30, relay station 10 may synchronize with a synchronization signal (PSS (Primary Synchronization Signal) / SSS (Secondary Synchronization Signal)) received from base station 30 (similar to the initial access procedure of 5G New Radio). Relay station 10 may update its clock each time it receives a synchronization signal periodically transmitted from base station 30. Alternatively, synchronization between relay station 10 and terminal 20 may be achieved by relay station 10 and terminal 20 synchronizing with each other using a synchronization signal received from base station 30, or by relay station 10 periodically transmitting a synchronization signal and terminal 20 updating its clock accordingly.

[0021] 3 is a flowchart showing an example of the flow of relay processing according to an embodiment of the present invention. At the start of relay processing, relay station 10 determines a beam number to be used for each terminal 20 (step S101). For example, relay station 10 transmits a beamformed SS / PBCH (Synchronization Signal and Physical Broadcast Channel) block multiple times using different beams.

[0022] The SS / PBCH is a downlink signal broadcast at the time of initial connection. The SS / PBCH block is a signal block that includes a synchronization signal and broadcast information. When there are multiple beamforming patterns, the relay station 10 transmits the SS / PBCH block using different beams. Note that the multiple beams being the same may mean that the multiple beams are in a QCL (Quasi Colocation) relationship with each other.

[0023] Terminal 20 transmits a PRACH (Physical Random Access Channel) to relay station 10 using resources corresponding to a beam with good quality from the received SS / PBCH block. The PRACH is an uplink signal transmitted by a random access procedure using resources designated for the SS / PBCH block with good reception quality. Relay station 10 receives the PRACH from terminal 20 and determines the beam number to use for each terminal 20 based on the received PRACH.

[0024] The relay station 10 may re-execute the process of step S101 at regular time intervals or when synchronization with the terminal 20 is lost.

[0025] Next, the schedule information acquisition unit 11 acquires schedule information from the base station 30 (step S102). Specifically, the schedule information acquisition unit 11 extracts the schedule information from the PDCCH transmitted from the base station 30. Note that, as long as the relay station 10 can decode the PDCCH transmitted from the base station 30, it may relay the signal using either a regenerative relay method or a non-regenerative relay method.

[0026] Based on the schedule information, relay function control unit 12 controls ON / OFF of the relay function (step S103). For example, based on the schedule information, relay function control unit 12 identifies either or both of the time resource and the frequency resource of the signal that relay station 10 itself relays and that is transmitted to or received from terminal 20, and turns on (enables) the relay function only when either or both of the identified time resource and the frequency resource are used. This allows relay station 10 to relay only to terminal 20 connected to itself (that has transmitted the PRACH).

[0027] Next, the beam control unit 13 relays the signal transmitted from the base station 30 to the terminal 20, using the beam corresponding to the beam number determined for each terminal 20 (step S104). Specifically, the beam control unit 13 identifies the destination terminal 20 based on the schedule information, and determines the beam to be used for each terminal 20 identified as the destination based on the beam number defined in advance for each terminal 20.

[0028] The relay station 10 according to this embodiment can relay signals only when relaying is necessary. This reduces interference with other devices, terminals, etc., suppresses emission of unnecessary beams, and reduces power consumption. The relay station 10 can also transmit signals to terminals 20 using beams formed by beamforming. This reduces interference with other devices, terminals, etc., and improves the radio wave quality of transmission and reception with the desired terminal 20. This reduces radio wave interference caused by signals transmitted by relay stations in a wireless communication network.

[0029] <Hardware configuration> Finally, a description will be given of the hardware configuration of the relay station 10, terminal 20, or base station 30 according to this embodiment. The relay station 10, terminal 20, or base station 30 according to this embodiment is realized, for example, by the hardware configuration of a computer 500 shown in FIG.

[0030] 4 includes an input device 501, a display device 502, an external I / F 503, a communication I / F 504, a processor 505, and a memory device 506. Each of these pieces of hardware is connected to each other via a bus 507 so as to be able to communicate with each other.

[0031] The input device 501 is, for example, a keyboard, a mouse, a touch panel, etc. The display device 502 is, for example, a display, etc. Note that the computer 500 does not necessarily have to have at least one of the input device 501 and the display device 502.

[0032] The external I / F 503 is an interface with an external device such as a recording medium 503a. Examples of the recording medium 503a include a CD (Compact Disc), a DVD (Digital Versatile Disk), an SD memory card (Secure Digital memory card), and a USB (Universal Serial Bus) memory card.

[0033] The communication I / F 504 is an interface for performing data communication with other devices, equipment, systems, etc. The processor 505 is, for example, various types of arithmetic devices such as a CPU, etc. The memory device 506 is, for example, various types of storage devices such as an HDD, SSD, RAM (Random Access Memory), ROM (Read Only Memory), flash memory, etc.

[0034] The relay station 10, terminal 20, or base station 30 according to this embodiment can realize the various processes described above by having the hardware configuration of the computer 500 shown in Fig. 4. Note that the hardware configuration of the computer 500 shown in Fig. 4 is an example, and the computer 500 may have other hardware configurations. For example, the computer 500 may have multiple processors 505 or multiple memory devices 506.

[0035] The relay station 10, terminal 20, or base station 30 according to this embodiment is realized by reading a program for causing the computer 500 to execute each of the above-described processes and executing the processes defined in the program. The program may be recorded on a recording medium 503a or the like, or may be provided via a network.

[0036] (Summary of the embodiment) This specification describes at least the wireless communication system, relay station, and relay method described in the following sections. (Section 1) A wireless communication system comprising a base station that transmits and receives signals to and from a terminal, and a relay station that relays signals between the base station and the terminal, The base station a scheduling function unit that determines a schedule for transmitting and receiving signals to and from a plurality of terminals 20 and transmits schedule information indicating the determined schedule to the relay station; The relay station a schedule information acquisition unit that acquires the schedule information from the base station; a beam control unit that identifies a destination terminal based on the schedule information and controls a beam to be used for relaying for each terminal identified as a destination based on a beam number predefined for each terminal; Wireless communication system. (Section 2) The relay station a relay function control unit that controls whether to enable a function of relaying a signal between the base station and the terminal based on the schedule information; 2. The wireless communication system according to claim 1. (Section 3) the relay function control unit, based on the schedule information, identifies one or both of a time resource and a frequency resource of a signal to be relayed by itself and to be transmitted to or received from the terminal, and enables a function of relaying a signal between the base station and the terminal when using one or both of the identified time resource and the identified frequency resource. 3. The wireless communication system according to claim 2. (Section 4) A relay station that relays signals between a base station and a terminal, a schedule information acquisition unit that acquires schedule information from the base station; a beam control unit that identifies a destination terminal based on the schedule information and controls a beam to be used for relaying for each terminal identified as a destination based on a beam number predefined for each terminal; Relay station. (Section 5) A relay method performed by a relay station that relays signals between a base station and a terminal, comprising: obtaining schedule information from the base station; Identifying a destination terminal based on the schedule information, and controlling a beam to be used for relay for each terminal identified as a destination based on a beam number predefined for each terminal. Relay method.

[0037] Although the present embodiment has been described above, the present invention is not limited to such a specific embodiment, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims. [Explanation of symbols]

[0038] 1. Wireless communication systems 10 Relay Station 11 Schedule information acquisition section 12 Relay function control section 13 Beam control section 20 terminals 30 base station 31 Scheduling Function Unit 40 Core Network 500 computers 501 Input Device 502 Display device 503 External I / F 503a Recording media 504 Communication I / F 505 processor 506 Memory Device 507 Bus

Claims

1. A wireless communication system comprising a base station that transmits and receives signals to and from a terminal, and a relay station that relays signals between the base station and the terminal, The base station a scheduling function unit that determines a schedule for transmitting and receiving signals to and from a plurality of terminals and transmits schedule information indicating the determined schedule to the relay station; The relay station a schedule information acquisition unit that acquires the schedule information from the base station; a beam control unit that identifies a destination terminal based on the schedule information, and controls a beam to be used for relay for each terminal identified as a destination based on a beam number predefined for each terminal; The relay station a relay function control unit that controls whether to enable a function of relaying a signal between the base station and the terminal based on the schedule information; Wireless communication system.

2. the relay function control unit, based on the schedule information, identifies one or both of a time resource and a frequency resource of a signal to be relayed by itself and to be transmitted to or received from the terminal, and enables a function of relaying a signal between the base station and the terminal when using one or both of the identified time resource and the identified frequency resource.

10. The wireless communication system of claim 1.

3. A relay station that relays signals between a base station and a terminal, a schedule information acquisition unit that acquires schedule information from the base station; a beam control unit that identifies a destination terminal based on the schedule information, and controls a beam to be used for relay for each terminal identified as a destination based on a beam number predefined for each terminal, a relay function control unit that controls whether to enable a function of relaying a signal between the base station and the terminal based on the schedule information; Relay station.

4. A relay method performed by a relay station that relays signals between a base station and a terminal, comprising: obtaining schedule information from the base station; a step of identifying a destination terminal based on the schedule information, and controlling a beam to be used for relay for each terminal identified as a destination based on a beam number predefined for each terminal, The method further includes controlling whether to enable a function of relaying a signal between the base station and the terminal based on the schedule information. Relay method.

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