Deflection device, base station apparatus, and method therefor

Abstract

To reduce the amount of information stored in the deflection device for controlling the deflection direction of a radio signal in a deflection device having a deflection surface capable of controlling the direction of a radio signal.SOLUTION: A deflection device includes a deflection surface capable of controlling the direction of a radio signal, acquisition means for acquiring information indicating the incident direction of a target radio signal transmitted by a target base station device among a plurality of base station devices onto the deflection surface, and control means for controlling the deflection surface on the basis of the information indicating the incident direction of the target radio signal onto the deflection surface such that the target radio signal is deflected in a predetermined direction.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a control technique for a deflection device having a deflection surface capable of controlling the direction of a radio signal. [Background technology]

[0002] A mobile communication network includes multiple base station devices (BS), and the multiple BSs provide communication services to wireless devices (WDs) that exist in a specific geographical area (service area). However, in a mobile communication network, blind areas may occur within the service area, making it difficult to transmit and receive wireless signals to and from the WD. For this reason, Non-Patent Document 1 discloses a network controlled repeater (NCR) that relays signals between the BS and the WD. According to Non-Patent Document 1, the NCR is controlled by the BS. For this reason, the NCR performs a random access procedure to the BS to establish a control link with the BS.

[0003] Meanwhile, in recent years, a deflection device called a RIS (Reconfigurable Intelligent Surface) has been attracting attention. A RIS has a deflection surface that controls the direction of a radio signal. As an example, a RIS has a reflecting surface that reflects a radio signal, and can control the reflection direction of the radio signal on the reflecting surface based on configuration information called a codebook. In other words, a RIS is a deflection device that has a deflection surface that can control the deflection direction of a radio signal. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] 3GPP(registered trademark) TR38.867, V18.0.0, September 2022 Summary of the Invention [Problem to be solved by the invention]

[0005] Fig. 1 is an explanatory diagram of the operation of RIS1. Note that, although the following describes the operation in the downstream direction from BS2 to WD, the operation in the upstream direction from WD to BS2 is similar. Also, in Fig. 1, M pieces of BS2 (M is an integer of 2 or more) are shown, but when each BS2 is to be distinguished, it is expressed as BS#m (m is an integer from 1 to M).

[0006] The RIS1 has N codebooks (N is an integer equal to or greater than 1) to deflect the radio signal from the BS#1 toward the target area 3, which is a blind area. The codebooks are control information or configuration information used to control the deflection plane of the RIS1. For example, when the deflection plane is configured based on the codebook #1-1, the RIS1 deflects the radio signal from the BS#1 as a radio signal #1, when the deflection plane is configured based on the codebook #1-2, the RIS1 deflects the radio signal from the BS#1 as a radio signal #2, and when the deflection plane is configured based on the codebook #1-N, the RIS1 deflects the radio signal from the BS#1 as a radio signal #N. Note that in FIG. 1, for the sake of simplicity, the radio signals deflected by the RIS1 are shown as straight lines, but in reality, the radio signals deflected by the RIS1 propagate through space with a spatial spread. The entire target area 3 can be covered by the radio signals #1 to #N.

[0007] Similarly, to convert the wireless signal from BS#2 into wireless signals #1 to #N, codebooks #2-1 to #2-N different from codebooks #1-1 to #1-N are required. This is because the direction of incidence of the wireless signal from BS#2 to RIS1 is different from the direction of incidence of the wireless signal from BS#1 to RIS1. Therefore, as shown in FIG. 1, if RIS1 is used to relay the wireless signals of BS#1 to BS#M, a total of M×N codebooks are required, and the amount of information to be stored in RIS1 increases.

[0008] The present disclosure provides a technique for reducing the amount of information stored in a deflection device having a deflection surface capable of controlling the deflection direction of a radio signal in order to control the deflection direction of the radio signal. [Means for solving the problem]

[0009] According to one aspect of the present disclosure, a deflection device includes a deflection surface capable of controlling the direction of a radio signal, an acquisition means for acquiring information indicating the incident direction of a target radio signal transmitted by a target base station device among a plurality of base station devices onto the deflection surface, and a control means for controlling the deflection surface based on the information indicating the incident direction of the target radio signal onto the deflection surface so that the target radio signal is deflected in a predetermined direction. Effect of the Invention

[0010] According to the present disclosure, in a deflection device having a deflection surface capable of controlling the deflection direction of a radio signal, it is possible to reduce the amount of information stored in the deflection device for controlling the deflection direction of the radio signal. [Brief description of the drawings]

[0011] [Figure 1] RIS operation diagram. [Diagram 2] FIG. 2 shows an example of the configuration of a RIS. [Diagram 3] FIG. 11 is a diagram showing an example of incident direction information. [Figure 4] FIG. 2 is a sequence diagram according to one embodiment. [Diagram 5] FIG. 1 shows an example of the configuration of a BS. [Figure 6] FIG. 2 is a sequence diagram according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims, and not all combinations of features described in the embodiments are essential to the invention. Two or more features among the multiple features described in the embodiments may be arbitrarily combined. In addition, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0013] In the following embodiments, the RIS reflects a radio signal and controls the direction of the radio signal by controlling the direction of the reflected signal. However, the RIS has a surface that transmits the radio signal, and the direction of the radio signal is controlled by controlling the output direction of the transmitted radio signal from the surface, and the control of the direction of the radio signal is not limited to reflection.

[0014] First Embodiment The system configuration according to this embodiment is as shown in FIG. 1. The following description of the embodiment will be based on the operation in the downlink direction from BS2 to WD, but the same applies to the uplink direction from WD to BS2. RIS1 reflects a wireless signal from BS2 toward the target area 3 in order to provide communication services to WDs present in the target area 3. At a certain moment, RIS1 operates to reflect a wireless signal from one of BS2 among BS#1 to BS#M toward the target area 3. In the following description, the BS2 that is the transmission source of the wireless signal reflected toward the target area 3 is referred to as the target BS.

[0015] FIG. 2 is a diagram showing a configuration example of the RIS1. The RIS1 has a configurable reflective surface 14. The control unit 13 controls the configurable reflective surface 14 based on information stored in the storage unit 12, which will be described later, to control the reflection direction of the radio signal by the configurable reflective surface 14. The control unit 13 has, for example, one or more processors and one or more memory devices. The one or more memory devices include, for example, a volatile memory device and a non-volatile memory device. The non-volatile memory device stores a computer program executable by the one or more processors. The one or more processors perform the process described below by executing the computer program stored in the non-volatile memory device. The communication processing unit 11 performs a process of establishing a control link with the BS2.

[0016] The storage unit 12 stores in advance the incident direction information shown in Fig. 3. The incident direction information includes, for each of BS#1 to BS#M, information indicating the identifier of BS2 and the incident direction of the wireless signal from the BS2 on the configurable reflecting surface 14. For example, the incident direction is expressed by an azimuth angle θ and an elevation / depression angle Φ, and may also be referred to as angle information. In Fig. 3, the incident direction of the wireless signal from BS#1 is (θ1, Φ1), the incident direction of the wireless signal from BS#2 is (θ2, Φ2), and the incident direction of the wireless signal from BS#M is (θM, ΦM).

[0017] Furthermore, N basic codebooks #1 to #N are stored in advance in the storage unit 12. The basic codebook #n (n is an integer from 1 to N) is reference control information or reference configuration information for controlling the configurable reflective surface 14 so that when the incident direction of a wireless signal to the configurable reflective surface 14 is a reference direction (θR, ΦR), the wireless signal is transmitted as a wireless signal #n. Note that the transmission direction of each of the wireless signals #1 to #N is a predetermined direction, which is determined in advance so as to cover the target area 3.

[0018] FIG. 4 is a sequence diagram according to this embodiment. The process of FIG. 4 is basically the same as the random access procedure for BS2. In S1, the communication processing unit 11 of RIS1 transmits a RACH preamble (MSG1) to BS2. In S2, BS2 transmits a RACH response (MSG2) to RIS1 as a response to the RACH preamble. In S3, the communication processing unit 11 of RIS1 transmits an RRC (Radio Resource Control) connection request message (MSG3) to BS2. In S4, BS2 transmits an RRC connection setup message (MSG4) to RIS1. At this time, BS2 notifies RIS1 of the identifier of the target BS. In other words, in S4, the communication processing unit 11 of RIS1 acquires the identifier of the target BS. In this way, the communication processing unit 11 functions as an acquisition unit that acquires the identifier of the target BS. In S5, the communication processing unit 11 of RIS1 transmits an RRC connection setup completion message (MSG5) to BS2.

[0019] In addition, the "target BS" whose identifier is notified to RIS1 by BS2 in S4 of FIG. 4 may be the identifier of the BS2. In other words, if BS2 in FIG. 4 is BS#1, the "target BS" whose identifier is notified to RIS1 by BS#1 in S4 of FIG. 4 may be the identifier of BS#1. Alternatively, if BS#1 has a function of controlling another BS2, the "target BS" whose identifier is notified to RIS1 by BS2 in S4 of FIG. 4 may be the identifier of a BS2 different from the BS2. In other words, if BS2 in FIG. 4 is BS#1, the "target BS" whose identifier is notified to RIS1 by BS#1 in S4 of FIG. 4 may be the identifier of a BS2 different from BS#1.

[0020] When the controller 13 is notified of the identifier of the target BS, the controller 13 determines the angle information (indicating the incident direction) of the target BS based on the incident direction information, and corrects N basic codebooks #1 to #N based on the determined angle information to generate N codebooks #1 to #N. For example, when the target BS is BS#1, the codebook #n is generated by correcting the basic codebook #n based on the difference between the reference direction (θR, ΦR) and the incident direction (θ1, Φ1) of the wireless signal from BS#1 indicated by the angle information of BS#1. The controller 13 selects from the generated codebooks #1 to #N a utilization codebook to be used for configuring the configurable reflecting surface 14 so as to reflect the target wireless signal from the target BS toward the WD of the communication target present in the target area 3. As an example, the controller 13 sequentially selects the generated codebooks #1 to #N to configure the configurable reflecting surface 14 to change the reflection direction of the wireless signal from the target BS, thereby being able to select a utilization codebook for reflecting the wireless signal from the target BS toward the WD of the communication target.

[0021] With the above configuration, the information stored in storage unit 12 is N basic codebooks #1 to #N, the reference direction (θR, ΦR), and incident direction information, and the amount of information stored in storage unit 12 can be reduced compared to a configuration in which N codebooks are stored for each of BS#1 to BS#M.

[0022] Second Embodiment Next, the second embodiment will be described focusing on the differences from the first embodiment. In the first embodiment, the incident direction information is stored in advance in the storage unit 12. In this embodiment, the incident direction information is stored in the BS2. The incident direction information stored in the BS2 includes angle information about the BS2 and the BS2 controlled by the BS2.

[0023] 5 is a configuration diagram of the BS2 according to this embodiment. The communication processing unit 23 performs communication processing with the network nodes of the core network and transmission and reception processing of radio signals with the WD or the RIS1. The storage unit 22 stores incident direction information in advance. The RIS control unit 21 controls the RIS1 that sets up the RRC connection. The configuration of the RIS1 in this embodiment is the same as that of the first embodiment, except that the storage unit 12 does not store incident direction information in advance.

[0024] FIG. 6 is a sequence diagram according to this embodiment. In FIG. 6, the same step numbers are assigned to the same processing steps as those in the sequence of FIG. 4, and the description thereof will be omitted. In this embodiment, the RIS control unit 21 transmits an RRC connection setup (MSG4) to the RIS1 in S40, and transmits and notifies the angle information of the target BS to the RIS1 in this MSG4. In this manner, the RIS control unit 21 functions as a transmitting unit that transmits the angle information of the target BS to the RIS1. Similarly, in this embodiment, the communication processing unit 11 of the RIS1 functions as an acquiring unit that acquires the angle information of the target BS. In the first embodiment, the RIS control unit 21 functions as a transmitting unit that transmits the identifier of the target BS to the RIS1. Therefore, the control unit 13 of the RIS1 can generate codebooks #1 to #N for reflecting a wireless signal toward the target area 3 based on the incident direction indicated by the notified angle information of the target BS and N basic codebooks #1 to #N stored in the storage unit 12.

[0025] With the above configuration, the information stored in storage unit 12 is N basic codebooks #1 to #N and the reference direction (θR, ΦR), which makes it possible to reduce the amount of information stored in storage unit 12 compared to storing N codebooks for each of BS#1 to BS#M.

[0026] <Other embodiments> In the first and second embodiments, N basic codebooks #1 to #N and a reference direction (θR, ΦR) are stored in advance in the storage unit 12 of the RIS 1. However, instead of the N basic codebooks #1 to #N and the reference direction (θR, ΦR), reflection direction information indicating the reflection direction of each of the wireless signals #1 to #N may be stored. The reflection direction information of the wireless signal #n is information indicating the reflection direction of the wireless signal #n on the configurable reflecting surface 14 of the RIS 1, and can be expressed by an azimuth angle θ and an elevation / depression angle Φ, similar to the incident direction information. The control unit 13 can generate N codebooks #1 to #N based on the incident direction of the wireless signal from the target BS and the reflection direction information corresponding to each of the wireless signals #1 to #N.

[0027] In the first and second embodiments, BS2 notifies RIS1 of the identifier of the target BS and the angle information of the target BS in MSG4 of the random access procedure, but it can also be configured to notify RIS1 of the identifier of the target BS and the angle information of the target BS in another RRC message. In other words, BS2 that has set up an RRC connection with RIS1 can be configured to notify RIS1 of the identifier of the target BS and the angle information of the target BS at any timing. In this case, the RRC message used to notify RIS1 of the identifier of the target BS and the angle information of the target BS may be a newly defined RRC message or a modified version of an existing RRC message.

[0028] The BS2 may be configured as a single device, or may be configured as multiple units that may be located at different geographical locations, such as a radio unit (RU), a distributed unit (DU), and a central unit (CU). Furthermore, the BS2 may be configured such that each of the DU and CU is divided into a user plane and a control plane.

[0029] In addition, when the wireless signal is transmitted rather than reflected, the term "reflect" in the above embodiment is replaced with "transmit". For example, the configurable reflective surface 14 of the RIS1 is replaced with a configurable transmitting surface. More generally, the RIS1 deflects the wireless signal, and the term "reflect" in the above embodiment is replaced with "deflection". For example, the configurable reflective surface 14 of the RIS1 is replaced with a configurable deflecting surface.

[0030] According to this embodiment, in a deflection device having a deflection surface capable of controlling the deflection direction of a wireless signal, the amount of information stored in the deflection device for controlling the deflection direction of the wireless signal can be reduced. Therefore, it is possible to contribute to Goal 9 of the Sustainable Development Goals (SDGs) led by the United Nations, "Build resilient infrastructure, promote sustainable industrialization and foster innovation."

[0031] The invention is not limited to the above-described embodiment, and various modifications and variations are possible within the scope of the gist of the invention. [Explanation of symbols]

[0032] 11: communication processing unit, 13: control unit

Claims

1. A deflection surface capable of controlling the direction of a wireless signal; an acquisition means for acquiring information indicating an incident direction of a target radio signal transmitted by a target base station device among a plurality of base station devices onto the deflection plane; a control means for controlling the deflection surface based on information indicating an incident direction of the target radio signal on the deflection surface so that the target radio signal is deflected in a predetermined direction; A deflection device comprising:

2. a storage unit for storing incident direction information indicating an incident direction of a radio signal transmitted from each of the plurality of base station devices on the deflection surface, The deflection device according to claim 1 , wherein the acquisition unit acquires information that identifies the target base station device, thereby acquiring information indicating an incident direction of the target radio signal on the deflection plane.

3. The deflection device according to claim 1 , wherein the acquisition means acquires information indicating the direction of incidence of the target radio signal on the deflection surface from the target base station device or another base station device among the plurality of base station devices that is different from the target base station device.

4. The deflection device of claim 3, wherein the acquisition means acquires information indicating the incident direction of the target radio signal on the deflection surface by receiving a Radio Resource Control (RRC) message from the target base station device or the other base station device, the RRC message including information indicating the incident direction of the target radio signal on the deflection surface.

5. The deflection device of claim 4 , wherein the RRC message is an RRC connection setup message.

6. A storage unit for storing direction information indicating the predetermined direction is further provided.

2. The deflection device according to claim 1, wherein the control means controls the deflection surface based on information indicating an incident direction of the target radio signal on the deflection surface and the directional information so that the target radio signal is deflected in the predetermined direction.

7. a storage unit for storing information indicating a reference direction and reference control information for controlling the deflection surface so as to deflect a radio signal from the reference direction in the predetermined direction; 2. The deflection device according to claim 1, wherein the control means controls the deflection surface so that the target radio signal is deflected in the predetermined direction by modifying the reference control information based on a difference between an incident direction of the target radio signal on the deflection surface and the reference direction.

8. A method for controlling the direction of a radio signal using a deflection device having a deflection surface. acquiring information indicating an incident direction of a target wireless signal transmitted by a target base station device among a plurality of base station devices onto the deflection plane; controlling the deflection surface based on information indicating an incident direction of the target radio signal on the deflection surface so that the target radio signal is deflected in a predetermined direction; The method includes:

9. A base station apparatus that communicates with a deflection device having a deflection surface capable of controlling the direction of a radio signal. A base station apparatus comprising: a transmitting means for transmitting, to the deflection device, information indicating an incident direction, on the deflection surface, of a radio signal transmitted by the base station apparatus or another base station apparatus.

10. the deflection device stores incident direction information indicating an incident direction, on the deflection surface, of a radio signal transmitted from each of a plurality of base station devices including the base station device and the other base station device; The base station device according to claim 9, wherein the transmitting means transmits information identifying the base station device or the other base station device to the deflection device, thereby transmitting information indicating the direction of incidence of a radio signal transmitted by the base station device or the other base station device onto the deflection surface to the deflection device.

11. The base station apparatus according to claim 9, wherein the transmitting means transmits information indicating an incident direction of a radio signal transmitted by the base station apparatus or the other base station apparatus to the deflection surface in a radio resource control (RRC) message to the deflection device.

12. The base station apparatus according to claim 11 , wherein the RRC message is an RRC connection setup message.

13. A method for a base station apparatus communicating with a deflection device having a deflection surface capable of controlling the direction of a radio signal, A method comprising: transmitting, to the deflection device, information indicating a direction of incidence of a radio signal transmitted by the base station apparatus or another base station apparatus on the deflection surface.

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