Base station device for controlling plurality of reflector plates, control device, control method, and program

Abstract

This base station device capable of communicating with a terminal device via a plurality of reflection devices for reflecting radio waves is provided with a feature in which an area where the terminal device can communicate with the base station device, is formed by reflection based on the reflection patterns of the reflection devices, the reflection devices being connected to a control device for controlling the reflection patterns of the reflection devices. The base station device selects a first reflection pattern to be set for a first reflection device such that a first area formed by reflection of the first reflection device included in the plurality of reflection devices includes a geographical position where the terminal device exists, selects a second reflection pattern to be set for a second reflection device such that a second area formed by reflection of a second reflection device different from the first reflection device included in the plurality of reflection devices is at least partially different from the first area and is adjacent to the first area, and provides the control device with an instruction including identification information with which the first reflection pattern and the second reflection pattern can be identified.

Description

Base station device, control device, control method, and program for controlling multiple reflectors

[0001] The present invention relates to a technique for controlling the reflection patterns of a plurality of reflectors.

[0002] In mobile communications, wireless communication services are provided to terminals located in positions where they can receive radio waves transmitted from base stations. Therefore, it is important that the radio waves transmitted by the base station reach the terminal's location appropriately. In particular, in recent wireless communication environments that tend to use high-frequency bands, wireless quality is easily degraded due to the influence of obstructions, etc., so the use of reflectors that reflect radio waves between the base station and the terminal has been considered. While reflectors can change the direction in which radio waves are reflected by changing their physical orientation, metasurface reflectors can be used to reflect radio waves in various directions through electrical control without changing their physical orientation. Non-Patent Document 1 describes a technology for applying a liquid crystal reflector to polarized multiple-input multiple-output (MIMO) systems.

[0003] H. Matsuno et al. , “Development of a Dual-Polarized Direction-Variable Liquid-Crystal Meta-Surface Reflector for Intelligent Reflecting Surface,” in IEEE Access, vol. 11, pp. 95757-95767, 2023

[0004] The present invention provides a technique for improving the continuity of communication by using multiple reflectors in a wireless communication system that uses reflectors.

[0005] A base station device according to one aspect of the present invention is a base station device capable of communicating with a terminal device via a reflector that reflects radio waves, wherein an area in which the terminal device can communicate with the base station device is formed by reflection based on the reflection pattern of the reflector, and wherein a plurality of the reflectors are connected to a single control device that controls the reflection pattern of the reflectors, and the base station device has a selection means that selects a first reflection pattern to be set on the first reflector so that a first area formed by reflection from a first reflector included in the plurality of reflectors includes a geographical location of the terminal device, and a selection means that selects a second reflection pattern to be set on the second reflector so that a second area formed by reflection from a second reflector different from the first reflector included in the plurality of reflectors is at least partially different from the first area and adjacent to the first area, and an instruction means that issues an instruction to the control device including specific information that can identify the first reflection pattern and the second reflection pattern.

[0006] According to the present invention, in a wireless communication system using reflectors, the continuity of communication can be improved by using a plurality of reflectors.

[0007] Other features and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings, in which the same or similar elements are designated by the same reference numerals.

[0008] The accompanying drawings are incorporated into and constitute a part of the specification, illustrate embodiments of the present invention, and together with the description are used to explain the principles of the present invention. Figure 1 is a diagram showing an example of the configuration of a wireless communication system. Figure 2 is a diagram showing an example of the hardware configuration of a base station and a control device. Figure 3 is a diagram showing an example of the functional configuration of a base station. Figure 4 is a diagram showing an example of the functional configuration of a control device. Figure 5 is a diagram showing the processing flow when a base station instructs each of multiple reflectors to change their reflection patterns. Figure 6 is a diagram showing an example of the configuration of a wireless communication system. Figure 7 is a diagram showing the processing flow when a base station determines whether or not a change in the reflection pattern of a reflector is necessary and instructs the change of the reflection pattern. Figure 8 is a diagram showing the processing flow when a base station instructs each of multiple reflectors to change their reflection patterns. Figure 9 is a diagram showing an example of the configuration of a wireless communication system.

[0009] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention as claimed, and not all combinations of features described in the embodiments are necessarily essential to the invention. Two or more of the features described in the embodiments may be combined in any desired manner. Furthermore, the same reference numerals are used to designate identical or similar components, and redundant descriptions will be omitted.

[0010] (System Configuration) FIG. 1 shows an example configuration of a wireless communication system according to this embodiment. The wireless communication system is, for example, a cellular communication system conforming to the cellular communication standard of the Third Generation Partnership Project (3GPP (registered trademark)). However, this is not limited to this, and the following discussion can be applied to a wireless communication system conforming to any wireless communication standard. The wireless communication system includes, for example, a base station 101, terminals 111 and 112, reflecting devices 121 and 122, and a control device 131. The terminal 111 is wirelessly connected to the base station 101 via the reflecting device 121. The terminal 112 is connected to the base station 101 via the reflecting device 122. The control device 131 is wiredly connected to the reflecting device 121 and the reflecting device 122. The control device 131 may also be wirelessly connected to the reflecting device 121 and the reflecting device 122. The control device 131 is wirelessly connected to the base station 101. An area within which communication with a base station is possible is called a cell, and terminals can wirelessly communicate with the base station within the range of the cell. For example, base station 101 constitutes cell 141. Here, if there is an obstacle between the base station and a terminal, radio waves transmitted from the base station may not be received by the terminal with sufficient strength, even within the cell. Such an area where the direct waves of radio waves transmitted from the base station are not received by the terminal with sufficient power (or where the direct waves of radio waves transmitted from the terminal are not received by the base station with sufficient power) may be called a blind zone. That is, if a terminal is in a blind zone, there is a high possibility that normal communication with the base station will not be possible. In particular, when radio waves in the high-frequency band are used, the presence of many obstacles around the base station and the terminal increases the possibility of a blind zone occurring. In FIG. 1 , it is assumed that a blind zone 161 is created by obstacle 151. That is, it is assumed that terminals 111 and 112 in the blind zone 161 are in a situation where they cannot receive the direct waves of radio waves transmitted from base station 101 with sufficient power. In such a situation, providing a reflecting device that reflects radio waves between the base station and the terminal may enable the terminal to receive the radio waves transmitted from the base station with sufficient power. That is, in FIG. 1, even though terminal 111 and terminal 112 are in blind zone 161, they may be able to communicate normally with base station 101 due to the waves reflected by reflectors 121 and 122, respectively.In this embodiment, the terminals 111 and 112 may be referred to as terminals 110 without distinction, and the reflecting devices 121 and 122 may be referred to as reflecting devices 120 without distinction. While FIG. 1 illustrates an example in which the terminals 111 and 112 are wirelessly connected to the base station 101, the number of terminals 110 connected to the base station 101 may be one or three or more. Furthermore, two or more base stations 101 may be included in the wireless communication system. Similarly, two or more control devices 131 may be connected to the base station 101, and the control device 131 may be connected to one or three or more reflecting devices 120. Furthermore, the number of reflecting devices relaying communication between the base station 101 and the terminal 110 may be two or more. There may be multiple obstacles 151 within the range of the cell 141, which may result in multiple blind zones 161. Furthermore, the blind zones 161 may have various shapes.

[0011] The terminal 110 is a terminal used by a user, and exchanges radio signals with the base station 101 via a wireless medium. The terminal 110 may be referred to as User Equipment (UE). The terminal 110 includes, for example, a smartphone, a mobile phone, a personal computer, a tablet terminal, a wearable terminal, an IoT (Internet of Things) terminal, etc. The base station 101 exchanges radio signals with the terminal 110 via a wireless medium. The base station 101 includes, for example, a gNB (next generation Node B), an eNB (evolved Node B), etc.

[0012] The reflecting device 120 reflects radio waves transmitted from the base station 101 in a predetermined reflection pattern. The reflecting device 120 also reflects radio waves transmitted from the terminal 110 in a predetermined reflection pattern. By appropriately setting the reflection pattern of the reflecting device 120, radio waves transmitted from the base station 101 can be reflected toward the terminal 110, and radio waves transmitted from the terminal 110 can be reflected toward the base station 101. This allows radio waves transmitted from the base station 101 to be received by the terminal 110 with sufficient strength, and radio waves transmitted from the terminal 110 to be received by the base station 101 with sufficient strength. Here, the reflection pattern is a pattern that indicates the gain of the reflector for each direction, and is determined by the reflection phase set in the reflecting elements that constitute the reflector of the reflecting device 120. For example, this pattern may be such that radio waves incident from a predetermined incident direction are hardly attenuated, and radio waves incident from another incident direction are attenuated to almost zero. Furthermore, radio waves emitted in a predetermined direction are emitted with high power, while radio waves are hardly emitted in other directions. In this way, the reflection pattern is expressed by a combination of patterns that indicate the gains of the incident and emitted light.

[0013] The reflecting device 120 includes a reflector that reflects radio waves incident on the reflecting device 120 in a predetermined direction and is configured to be able to change the reflection pattern of the reflector. For example, the reflecting device 120 can change the reflection direction of radio waves transmitted from the base station 101 or the terminal 110 by physically controlling the attitude of the reflector so that it faces a desired direction. The reflecting device 120 may also be configured to include an Intelligent Reflecting Surface (IRS) reflector using a metasurface. The IRS reflector may be composed of, for example, multiple reflecting elements, and the reflection phase of each reflecting element may be electrically controlled to form a reflection pattern for the entire reflector. As an example, a metasurface reflecting device using a liquid crystal may have a reflector with a liquid crystal layer provided between the reflecting element and a ground (ground plate). In this reflecting device, the reflecting element is used as an electrode, and a voltage is applied to the reflecting element. By changing the voltage applied to the reflecting element, the electrical characteristics (dielectric constant) of the liquid crystal change, and the reflection phase of the reflecting element changes in response to the change in the dielectric constant of the liquid crystal. In this way, the reflection phase of the reflecting element can be precisely controlled by changing the voltage applied to the reflecting element. Therefore, by adjusting the voltage applied to each of the reflecting elements that make up the reflecting plate, the reflecting plate can be controlled to form a desired reflection pattern. In this way, by using a metasurface, the reflection direction of radio waves can be changed without physically changing the orientation or posture of the reflecting device. The reflecting device 120 may also have other reflection mechanisms. For example, the reflecting device 120 may include an IRS reflecting plate using a diode. In a metasurface reflecting plate using a diode, the reflecting element and the circuit element are connected by a diode. When a voltage is applied to the diode, a current flows in the circuit, resulting in a change in the reflection phase of the reflecting element. In this way, the reflection pattern of the reflecting device 120 can be controlled by the voltage applied to the diode. In this embodiment, the reflecting device 120 is described as having a metasurface reflecting plate using a liquid crystal.

[0014] The control device 131 is connected to the reflecting device 120 and controls the reflection pattern of the reflecting device 120. The control device 131 and the reflecting device 120 may be implemented as an integrated unit or as separate units. For example, the reflecting device 121 and the control device 131 may be implemented as an integrated unit, and the reflecting device 122 may be implemented as a separate unit. Furthermore, by wirelessly connecting the control device 131 and the base station 101, the base station 101 may remotely control the reflecting device 120 via the control device 131. For example, the control device 131 may have setting information (reflecting element setting) indicating the reflection phase to be set for each reflecting element of the reflecting device 120. The reflecting element setting includes information for identifying each reflecting element and information specifying the reflection phase to be set for each reflecting element. The information for identifying each reflecting element may be the position of each reflecting element on the reflecting plate, or may be an identifier that can uniquely identify a specific reflecting element on the entire reflecting plate. Furthermore, the information for specifying the reflection phase of each reflecting element may be the absolute value of the reflection phase or a relative value with respect to a reference value of the reflection phase. The information included in the reflecting element setting is not limited to these, and the information for identifying each reflecting element and the information for specifying the reflection phase of each reflecting element are also not limited to these. The control device 131 then controls the reflection phase of each reflecting element of the reflecting device 120 according to this reflecting element setting. For example, if the reflecting device 120 has an IRS reflector, the control device 131 may adjust the voltage applied to each reflecting element according to the reflection setting to be set for each reflecting element indicated in the reflecting element setting. Furthermore, one reflecting element setting may be associated with one reflection pattern formed by the reflecting device 120. For example, reflecting element settings corresponding to each reflection pattern may be generated and associated and stored in the control device 131. Furthermore, a pattern ID may be assigned to each reflection pattern as an identifier that uniquely identifies the reflection pattern. In other words, by specifying one pattern ID, one reflecting element setting associated with the reflection pattern corresponding to that pattern ID may be specified. For example, when a pattern ID is specified, the control device 131 may set the reflection phase of each reflecting element of the reflecting device 120 according to the reflecting element setting corresponding to that pattern ID.

[0015] The reflection pattern to be set in the reflecting device 120 can be notified to the control device 131 by the base station 101. For example, if a reflection pattern and a pattern ID are associated in advance and shared between the base station 101 and the control device 131, the base station 101 can notify the control device 131 of the pattern ID, and the control device 131 can acquire the reflection pattern to be set in the reflecting device 120. Note that the information that the base station 101 notifies the control device 131 is not limited to the pattern ID. For example, the reflecting element setting itself may be notified. In this embodiment, an example will be described in which the base station 101 notifies the reflection pattern of the reflecting device 120 using the pattern ID. Note that the base station 101 can generate reflecting element settings corresponding to each reflection pattern and provide them to the control device 131. Note that a device other than the base station 101 may generate reflecting element settings and provide them to the base station 101, and the base station 101 may provide the reflecting element settings to the control device 131.

[0016] As described above, providing the reflector 120 enables the terminal device 110 in a blind zone to communicate with the base station 101 with sufficient power. In particular, when using a reflector 120 including an IRS-based reflector, the reflection pattern is dynamically controlled according to the position of the terminal device 110, thereby improving the continuity of communication between the base station 101 and the terminal 110. That is, even in a situation where the terminal device 110 moves through a blind zone, dynamic control of the reflection pattern of the reflector makes it possible to maintain communication between the base station 101 and the terminal 110. However, it generally takes a certain amount of time to change the reflection pattern of a reflector based on an IRS. That is, when changing the reflection pattern of the reflector by controlling the voltage applied to the reflecting elements that make up the reflector, it takes a certain amount of time for the desired reflection pattern to be formed on the reflector. Therefore, if an attempt is made to maintain communication between the base station 101 and the terminal 110 while changing the reflection pattern of the reflector, there is a possibility that communication between the base station 101 and the terminal 110 will be interrupted while the reflection pattern of the reflector is being changed.

[0017] In consideration of these circumstances, in this embodiment, multiple reflecting devices 120 are connected to one control device 131 that controls the reflection patterns of the reflecting devices 120. A reflection pattern is set for each of the reflecting devices 120, and an area in which the terminal 110 can communicate with the base station 101 is formed by reflection from each reflecting device 120 based on the reflection pattern. The base station 101 selects a first reflection pattern to be set for a first reflecting device among the multiple reflecting devices so that a first area formed by reflection from a first reflecting device includes the geographical location of the terminal 110, and selects a second reflection pattern to be set for a second reflecting device so that a second area formed by reflection from a second reflecting device is at least partially different from the first area and adjacent to the first area. The base station 101 issues a control instruction for the reflection pattern to the control device 131, including identification information that can identify the first reflection pattern and the second reflection pattern. The control device 131 receives instructions from the base station 101, including specific information that can identify the reflection pattern to be set for each of the multiple reflecting devices, and controls the reflection pattern of each reflecting device in accordance with the instructions. This configuration increases the possibility that the terminal 110 can continue to communicate with the base station 101 when the terminal 110 in the blind zone moves out of the first area formed by the first reflecting device. This makes it possible to increase the continuity of communication between the base station 101 and the terminal 110. An example configuration of such a base station 101 and control device 131 will be described below.

[0018] (Device Configuration) FIG. 2 is a diagram showing the hardware configuration of the base station 101 and the control device 131. In one example, the base station 101 and the control device 131 are configured to include a processor 201, a ROM 202, a RAM 203, a storage device 204, and a communication circuit 205. The processor 201 is a computer configured to include one or more processing circuits, such as a general-purpose CPU (Central Processing Unit) or an ASIC (Application Specific Integrated Circuit). The processor 201 reads and executes programs stored in the ROM 202 or the storage device 204 to perform the overall processing of the device and each of the above-mentioned processes. The ROM 202 is a read-only memory that stores information such as programs and various parameters related to the processing executed by the base station 101 and the control device 131. The RAM 203 functions as a workspace when the processor 201 executes a program and is a random access memory that stores temporary information. The storage device 204 is configured, for example, by a removable external storage device. The communication circuitry 205 includes, for example, circuits for wired or wireless communication between the base station 101 and the control device 131 .

[0019] 3 is a diagram showing an example of the functional configuration of the base station 101. The base station 101 has, as its functions, for example, a reflection pattern selection unit 301, a reflection pattern instruction unit 302, a position information acquisition unit 303, and an information communication unit 304. Note that these functional units can be realized, for example, by the processor 201 executing a program stored in the ROM 202 or the storage device 204 and controlling the communication circuit 205 as necessary. However, this is not limiting, and for example, dedicated hardware for realizing each function may be provided.

[0020] The reflection pattern selection unit 301 selects a reflection pattern for the reflecting device 120 connected to the control device 131. For example, the reflection pattern selection unit 301 may select a reflection pattern for a first reflecting device so as to form a first area including a geographical range of the terminal 110 communicating with the base station 101, and may select a reflection pattern for a second reflecting device so as to form a second area that is at least partially different from the first area and adjacent to the first area. Note that, when the terminal 110 is located in the first area formed by reflection from the first reflecting device, the reflection pattern selection unit 301 may select a reflection pattern for the second reflecting device so as to form a second area that is at least partially different from the first area and adjacent to the first area. The reflection pattern instruction unit 302 issues an instruction to the control device 131 using the reflection pattern selected by the reflection pattern selection unit 301. The instruction from the reflection pattern instruction unit 302 may include identification information that identifies the reflecting device 120 for which a reflection pattern is to be set and specification information that specifies the reflection pattern to be set for the reflecting device 120. The location information acquisition unit 303 acquires information that can identify the location of the terminal 110. The location information acquisition unit 303 may acquire location information from the terminal 110, for example. Alternatively, the location information acquisition unit 303 may acquire information that can identify the location of the terminal 110 from a network node that manages the location of the terminal 110. Note that the information that can identify the location of the terminal 110 may include the movement path and direction of the terminal 110. The information communication unit 304 exchanges information necessary for controlling the reflection pattern of the reflecting device 120 with the control device 131. For example, the information communication unit 304 may acquire from the control device 131 the number of reflecting devices 120 connected to the control device 131, the reflection patterns that can be set for each of the reflecting devices 120, identification information that identifies each of the reflecting devices 120, and the like. Furthermore, the information communication unit 304 may notify the base station 101 of the identification information, etc., assigned to each of the reflecting devices 120.

[0021] 4 is a diagram showing an example of the functional configuration of the control device 131. The control device 131 has, as its functions, for example, a reflection pattern receiving unit 401, a reflection pattern control unit 402, and an information communication unit 403. Note that these functional units can be realized, for example, by the processor 201 executing a program stored in the ROM 202 or the storage device 204 and controlling the communication circuit 205 as necessary. However, this is not limiting, and for example, dedicated hardware for realizing each function may be provided.

[0022] The reflection pattern receiving unit 401 receives instructions from the base station 101, including a reflection pattern to be set for each of the reflecting devices 120 connected to the control device 131. The reflection pattern to be set for each of the reflecting devices 120 can be selected such that the reflection pattern of the first reflecting device is selected to form a first area including a geographical range of the terminals 110 communicating with the base station 101, and the reflection pattern of the second reflecting device is selected to form a second area that is at least partially different from the first area and adjacent to the first area. The reflection pattern control unit 402 sets the reflection patterns of the reflecting devices 120 based on the instructions received from the base station 101. The reflection pattern control unit 402 has reflection element settings corresponding to each reflection pattern and can set the reflection phase of each element of the reflector of the reflecting device 120 based on the specified reflection pattern. The information communication unit 403 exchanges information necessary for controlling the reflection pattern of the reflecting device 120 with the base station 101. For example, the information communication unit 403 can notify the base station 101 of the number of reflecting devices 120 connected to the control device 131, the reflection patterns that can be set for each of the reflecting devices 120, and identification information that identifies each of the reflecting devices 120. In addition, the information communication unit 403 can obtain the identification information, etc., assigned to each of the reflecting devices 120 from the base station 101.

[0023] (Processing Flow) (Processing Example 1) An example of the operation when the base station 101 communicates with the terminal 110 using a plurality of reflecting devices 120 connected to the control device 131 will be described. In this example, the explanation will be given using a case where the control device 131 is connected to the reflecting device 121 and the reflecting device 122, but the following discussion can also be applied to a case where the number of reflecting devices 120 connected to the control device 131 is three or more. This operation can be executed when the base station 101 establishes a wireless connection with the control device 131 and the control device 131 configures the reflecting device 120 based on an instruction from the base station 101.

[0024] 5 shows an example of a sequence in which the base station 101 sets the reflection patterns of the reflecting device 121 and the reflecting device 122 via the control device 131. First, the base station 101 establishes a wireless connection with the control device 131. For example, when the control device 131 is powered on, it performs a cell search to search for a cell that can be a connection destination. When the control device 131 detects a cell that can be a connection destination by receiving a synchronization signal transmitted by the base station 101, it acquires system information related to the cell and establishes an RRC (Radio Resource Control) connection with the base station 101 by performing a random access procedure based on the system information. For example, the control device 131 can acquire the location in the radio frame of a random access channel (PRACH) on which a preamble for accessing the base station 101 should be transmitted by receiving system information contained in a downlink physical broadcast channel (PBCH) transmitted by the base station 101. The control device 131 may notify the base station 101 of information about the control device 131 itself and the reflecting devices 120 connected to the control device 101 using the RRC connection established with the base station 101. For example, the control device 131 notifies the base station 101 of the number of reflecting devices 120 connected to the control device 101 (S501). Based on the number of reflecting devices 120 acquired from the control device 131, the base station 101 may recognize the number of reflecting devices 120 that the control device 131 can use in communication with the terminal 110, the number of reflection patterns that the control device 131 should include in a message when notifying the reflection pattern, and the like. For example, based on the number of reflecting devices 120, the base station 101 may provide the control device 131 with identification information that identifies each reflecting device 120. This allows the base station 101 to specify the reflecting device 120 to the control device 131 and set the reflection pattern between the base station 101 and the reflecting device 120.

[0025] Meanwhile, the control device 131 may provide the base station 101 with identification information for identifying each reflecting device 120, in addition to or instead of the number of reflecting devices 120. As an example, the control device 131 may assign an identifier for uniquely identifying each of the multiple reflecting devices 120 connected to the control device 131. This identifier may be referred to as a reflecting device identifier or an IRS ID. IRS ID may be an abbreviation for IRS Identifier. As described above, the base station 101 may assign a reflecting device identifier to each reflecting device 120 based on the number of reflecting devices 120 obtained from the control device 131, and provide the reflecting device identifier to the control device 131. Furthermore, the control device 131 may notify the base station 101 of information associated with each reflecting device 120, in addition to the reflecting device identifier of each reflecting device 120. For example, the information associated with each reflecting device 120 may include the type of reflector, the number of reflectors, the number of reflecting elements, the shape of the reflector, etc., of the reflector included in the reflecting device 120. The control device 131 may also notify the base station 101 of information that can identify each of the reflection patterns that can be set for each of the reflection devices 120. The information that can identify a reflection pattern may be, for example, a combination of an incident pattern and an exit pattern for each of the reflection patterns. The control device 131 may also associate each reflection pattern with a pattern ID and notify the base station 101 of the association.

[0026] When the base station 101 acquires the number of reflecting devices 120 and the like from the control device 131, it determines a reflection pattern for each reflecting device 120 (S502). For example, if the control device 131 provides reflection patterns that can be set for each reflecting device 120, the base station 101 can select one from the predetermined reflection patterns. Note that if the base station 101 does not acquire a predetermined reflection pattern from the control device 131, the base station 101 may generate a reflection pattern itself or may receive a reflection pattern from another device. In this embodiment, the base station 101 will be described assuming that multiple reflection patterns and pattern IDs associated with each reflection pattern are shared between the base station 101 and the control device 131, and the base station 101 selects a reflection pattern for each reflecting device 120 from the multiple shared reflection patterns.

[0027] The base station 101 may determine a reflection pattern so that a desired geographical area becomes an area (referred to as an "extended area") in which the terminal 110 can communicate with the base station 101 through reflection by the reflecting device 120. For example, the base station 101 may estimate the range of the extended area based on the geographical arrangement of the base station 101 and the reflecting device 120 and the reflection pattern set on the reflecting device 120. As an example, the base station 101 may estimate an area in which the received power of the reflected wave is enhanced based on the angle of incidence on the reflecting device 120 of the radio wave transmitted from the base station 101 toward the reflecting device 120 and the emission direction in which the radio wave is enhanced in the reflection pattern set on the reflecting device 120. In this way, the base station 101 may recognize in advance the geographical range that will become the extended area when setting each reflection pattern for each reflecting device 120. For example, the base station 101 estimates the geographical range of the extended area covered by each combination of the reflecting device 120 and the reflection pattern, and stores them in association with each other. The base station 101 may then determine the reflection pattern of the reflecting device 120 based on this association to include the geographic area to be covered.

[0028] The base station 101 may also specify the geographical extent of the expansion area based on the actually measured received signal strength. For example, the base station 101 may measure the received signal strength for each combination of reflector 120 and reflection pattern at a predetermined location in a blind zone in advance, and store the combination of reflector 120 and reflection pattern that provides the highest received signal strength for each predetermined location, or the combination in which the received signal strength exceeds a predetermined threshold. The base station 101 may determine the reflection pattern based on information about the expansion area formed by the combination of reflector 120 and reflection pattern thus obtained in advance. In other words, the base station 101 stores the correspondence between the geographical extent of the expansion area and the combination of reflector 120 and reflection pattern specified based on calculation or measurement. Therefore, the base station 101 can identify the desired location to be covered, determine the expansion area that includes that location, and specify the combination of reflector 120 and reflection pattern that corresponds to the expansion area.

[0029] The base station 101 may determine the reflection pattern of each reflecting device 120 based on the location of the terminal 110. For example, if the base station 101 can acquire location information of the terminal 110 from the terminal 110, the base station 101 may use that information to recognize the location of the terminal 110. Then, the base station 101 may determine a reflecting device 120 and a reflection pattern corresponding to an extended area including the location of the terminal 110. For example, the base station 101 may identify a reflection pattern corresponding to an extended area including the location of the terminal 110 in its geographical range from among the reflection patterns of the reflecting devices 120. Then, the base station 101 may determine that reflection pattern as the reflection pattern of the first reflecting device. Note that the base station 101 may recognize the location of the terminal 110 using other methods. For example, if location information of the terminal 110 is managed in the wireless communication system, the base station 101 may acquire that information. The method by which the base station 101 acquires the location of the terminal 110 may be any method as long as the information enables the base station 101 to identify the extended area in which the second reflecting device should be formed.

[0030] The base station 101 uses the determined reflection pattern to instruct the control device 131. For example, the base station 101 instructs the control device 131 regarding the reflection pattern of the first reflection device (S503). The base station 101 may provide an instruction including specific information that can identify the determined reflection pattern and identification information that identifies the first reflection device to which the reflection pattern should be set. The specific information that can identify the reflection pattern may be a pattern ID. Note that the method by which the base station 101 instructs the control device 131 about the reflection pattern is not limited to this, and for example, the base station 101 may notify the control device 131 of the reflection element setting associated with the reflection pattern. Furthermore, the information that can identify the reflection device 120 may be a reflection device identifier (IRS ID).

[0031] Based on the instruction received from the base station, the control device 131 identifies the reflection pattern to be set and the reflecting device 120 for which the reflection pattern should be set as the control target (S504). For example, if the reflection pattern to be set is indicated by a pattern ID, the control device 131 may identify the reflection pattern using the association between the pattern ID and the reflection pattern previously shared with the base station 101. Furthermore, if the reflecting device 120 for which the reflection pattern should be set is indicated by a reflecting device identifier, the control device 131 may identify the reflecting device 120 corresponding to the reflecting device identifier previously shared with the base station 101 as the control target. The control device 131 then controls the reflection phase of the reflecting device 121 using the reflection pattern instructed for the control target (S505). For example, the control device 131 may set the reflection phase by applying a voltage to each reflecting element based on the reflecting element setting associated with the reflection pattern. In FIG. 5 , the control device 131 controls the reflection phase of the reflecting device 121 based on the base station 101 designating the reflecting device 121 as the first reflecting device.

[0032] Next, the base station 101 determines a reflection pattern for the second reflector (S506). The base station 101 may determine the reflection pattern to be set for the second reflector based on the reflection pattern determined for the first reflector. For example, the base station 101 may determine the reflection pattern to be set for the second reflector so that the second extended area formed by reflection from the second reflector is at least partially different from the first extended area formed by reflection from the first reflector and is adjacent to the first extended area. As an example, the base station 101 may select, from the reflection patterns of the second reflector, reflection patterns that form an extended area that is at least partially different from the first extended area and is adjacent to the first extended area, and determine one of the reflection patterns as the reflection pattern to be set for the second reflector. For example, similar to when determining the reflection pattern of the first reflector, the base station 101 may identify an expansion area that satisfies the above-described conditions from among expansion areas formed by combinations of pre-stored reflectors 120 and each reflection pattern, and determine the reflection pattern associated with that expansion area as the reflection pattern of the second reflector. When there are multiple candidate reflection patterns to be set for the second reflector, the base station 101 may select the reflection pattern that minimizes the geographical area of ​​overlap between the second expansion area and the first expansion area. Furthermore, the base station 101 may determine the second reflection pattern so that at least a portion of the first expansion area differs from the second expansion area on the movement path of the terminal 110. For example, if the base station 101 can estimate the movement path and direction of the terminal 110, it may select a reflection pattern that forms the second expansion area in the direction of movement of the terminal 110 on that movement path. The base station 101 may determine the movement path and direction of movement of the terminal 110, for example, based on a time series of location information of the terminal 110. As an example, the base station 101 can estimate the moving path and direction of the terminal 110 by linear interpolation of the time series of past location information of the terminal 110 .The base station 101 may use other methods to estimate the terminal's movement path. For example, if movement information such as that obtained from an acceleration sensor or the like possessed by the terminal 110 can be obtained from the terminal 110, the base station 101 may use the information obtained from the terminal 110 to estimate the movement path and direction of travel of the terminal 110.

[0033] The base station 101 instructs the control device 131 regarding the reflection pattern of the second reflector (S507). For example, the base station 101 may provide the control device 131 with instructions including information that can specify the determined reflection pattern of the second reflector and information that identifies the second reflector. Then, based on the instructions received from the base station 101, the control device 131 specifies the reflection pattern to be set and the reflector 120 for which the reflection pattern should be set as the control target (S508), and controls the reflection phase using the instructed reflection pattern for the reflector 122 that is the control target (S509). The operations of each device in S507 to S509 are similar to those in S503 to S505, and therefore will not be described here.

[0034] In this way, by setting the reflection patterns so that the expansion areas formed by the two reflecting devices 120 are at least partially different and adjacent to each other, even if a terminal 110 communicating with the base station 101 in a first expansion area moves out of that area, the communication can be continued in a second expansion area. For example, in FIG. 1 , terminals 111 and 112 are communicating with the base station 101 in a first expansion area (not shown) formed by the reflecting device 121 and a second expansion area (not shown) formed by the reflecting device 122, respectively. In this case, even if the terminal 111 moves from the first expansion area to the second expansion area, the base station 101 can continue communication with the terminal 111 using the reflecting device 122.

[0035] If the base station 101 is capable of using a directional beam to transmit radio waves, it may shape the beam used to transmit radio waves so as to switch the reflector used for communication with the terminal 111 from the reflector 121 to the reflector 122. For example, the base station 101 may increase the intensity of radio waves emitted from the base station 101 toward the reflector 122 by switching the antenna used or controlling the electromagnetic wave radiation pattern using multiple antennas. Using a beam enables communication with terminals 110 located farther away, but the number of reflectors 120 that can reflect radio waves may be limited. For this reason, the base station 101 may communicate with the terminal 111 by controlling the beam to switch the reflector used for communication with the terminal 111. On the other hand, the base station 101 may use an omni-directional antenna. In this case, the range of radio waves is shorter compared to when beam control is performed, but the number of reflectors 120 that can reflect radio waves increases, thereby eliminating the load caused by beam control on the base station 101 and the need to exchange radio signals with the terminal 110 for beam control.

[0036] 5 illustrates an example in which the base station 101 sequentially determines the reflection pattern of the first reflector (S502) and issues an instruction (S503) and determines the reflection pattern of the second reflector (S506) and issues an instruction (S507). However, the base station 101 may also determine the reflection pattern of the first reflector and the reflection pattern of the second reflector together (S510). That is, the base station 101 may identify a combination of a first extended area formed by the first reflector and a second extended area formed by the second reflector that covers a desired geographical range, and determine the reflection pattern of each reflector based on that combination. For example, the base station 101 may store a correspondence between the combination of reflection patterns set for each of multiple reflectors and the extended area formed at that time. The base station 101 then determines the reflection pattern for each reflector so that a desired extended area is formed according to the location of the terminal 110. In order to generate such correspondences in advance, the base station 101 may measure and identify the geographical range of the extended area to be formed for each combination of reflecting devices connected to the control device 131 and each combination of reflection patterns set on the reflecting devices.

[0037] Furthermore, the base station 101 may issue instructions for the reflection pattern of the first reflector and the reflection pattern of the second reflector separately (S503, S507), or may issue instructions together (S511). For example, the base station 101 may transmit to the control device 131 a single instruction that associates specific information (pattern ID) of the reflection pattern to be set for one reflector 120 with identification information (reflector identifier, IRS ID, etc.) of the reflector 120 to be set. In this case, it is possible to issue instructions with a smaller amount of information than when notifying each time of the reflection patterns for all reflectors 120 connected to one control device 131. For example, if four reflectors 120 are connected to the control device 131 and each is associated with 32 reflection patterns (5 bits), the amount of information notified from the base station 101 to the control device 131 may be 20 bits (= 4 devices × 5 bits) if the reflection patterns for all reflectors 120 are notified each time. On the other hand, by notifying only the information for the reflector devices 120 for which a reflection pattern should be set, it is only necessary to notify the identification information of the reflector devices 120 (2 bits for four devices) and the reflection pattern (5 bits), so the amount of information notified from the base station 101 to the control device 131 can be 7 bits (= 2 bits + 5 bits). In this way, when the reflection pattern of a specific reflector device 120 is frequently changed, it is possible to reduce the amount of communication by notifying only the information of the reflector device 120 for which the reflection pattern should be changed. On the other hand, when the reflection patterns of multiple reflector devices 120 are changed frequently, issuing instructions with identification information may increase overhead. That is, if four reflector devices 120 are notified with identification information (2 bits each) and 5-bit reflection pattern identification information, the number of required bits could be 4 devices × (2 bits + 5 bits) = 28 bits. In this case, by notifying only the reflection pattern identification information without notifying the identification information assigned to each reflector device 120, it is possible to reduce the amount of information required to 20 bits. In this case, the base station 101 associates an order with each reflecting device and indicates specific information of the reflection pattern according to that order, thereby being able to notify the control device 131 of the reflection pattern to be set for each reflecting device without notifying the identification information.

[0038] The base station 101 may transmit instructions to the control device 131, including specific information about the reflection pattern to be set and identification information about the reflector device 120 to be set, using procedures and frames defined in the 3GPP cellular communication standard. As an example, the base station 101 may use a radio resource control (RRC) message to instruct the control device 131. In this case, for example, a new type of message for notifying the specific information and identification information may be defined in the RRC reconfiguration message. Upon receiving the RRC message, the control device 131 extracts information contained in the message. Then, based on the extracted information, the control device 131 identifies the reflection pattern to be set and the reflector device 120 to be set. The base station 101 may include a large amount of information in the RRC message. In addition, the control device 131 sends an acknowledgment response indicating that the RRC message was successfully received. This acknowledgment response allows the base station 101 to confirm that the reflection pattern of the reflector device 120 has been changed, enabling highly reliable control. On the other hand, in order to use an RRC message, an RRC connection must be established between the base station 101 and the control device 131. Therefore, when an RRC message is used, a processing load such as connection establishment occurs between the base station 101 and the control device 131 each time a message is exchanged. Therefore, the base station 101 may notify the specific information and identification information using an RRC message in cases where the base station 101 does not frequently update the reflection pattern of the reflector 120 and communicates with the terminal 110 while switching the reflector 120 used. In this case, the base station 101 may set the reflection pattern when establishing an RRC connection with the control device 131. Note that when an RRC message is used, the base station 101 may have a higher degree of freedom in notifying the identification information of the reflector and the specific information of the reflection pattern.

[0039] The base station 101 may also notify the control device 131 of the specific information and identification information using a medium access control (MAC) subheader. In this case, a new MAC subheader format may be defined for notifying such information. Alternatively, some fields in an existing MAC subheader may be diverted to notify such information. For example, a field with a predetermined number of bits may be provided in the MAC subheader for indicating such information. The control device 131 analyzes the MAC subheader included in the signal addressed to the base station 101 to acquire the specific information and identification information. The control device 131 then identifies the reflection pattern to be set and the reflector device 120 to be set based on the acquired specific information and identification information. The base station 101 may also notify the control device 131 of the specific information and identification information using downlink control information (DCI) defined in the 3GPP cellular communication standard. In this case, a new DCI format for notifying such information may be defined. Alternatively, some fields in an existing DCI format may be diverted to notify such information. For example, a field with a predetermined number of bits may be provided in the DCI for indicating the specific information and identification information. The control device 131 decodes the physical downlink control channel (PDCCH). In one example, a radio network temporary identifier (RNTI) can be assigned to the control device 131 in advance. In this case, the control device 131 can obtain information from the DCI addressed to the control device 131 by decoding the PDCCH using the RNTI. If the RNTI is assigned in advance, the control device 131 can decode the PDCCH simply by establishing time synchronization on the downlink (the link from the base station 101 to the control device 131) by observing a synchronization signal. That is, in this case, the control device 131 does not need to perform a random access procedure with the base station 101 to establish uplink synchronization or to establish a connection in the RRC layer. This eliminates the need for connection establishment processing, etc., and reduces the processing load. Therefore, in cases where the reflection pattern of the reflecting device 120 is frequently changed due to the movement of the terminal, the base station 101 can use this method to instruct a change in the reflection pattern.

[0040] Furthermore, a signaling protocol layer for notifying the specific information and identification information may be defined. For example, the protocol used in this layer may be called an Intelligent Reflecting Surface protocol (IRS protocol). This layer may also be called an IRS protocol layer. For example, the control device 131 receives a message of the IRS protocol layer and identifies the reflection pattern to be set and the reflector device 120 to be set based on the specific information and identification contained in the message. By defining the IRS protocol layer, it becomes possible to use a message format suitable for notifying the specific information and identification information. Furthermore, this method does not require an RRC connection, and therefore does not require the processing load for an RRC connection. Note that the above-mentioned methods for notifying the specific information and identification information may be used in combination with each other.

[0041] The control device 131 may notify the base station 101 of the number of reflecting devices 120 connected to the control device itself, information about the reflecting devices, and the like, using procedures and frames defined in the 3GPP cellular communication standard. As an example, the control device 131 may notify the base station 101 of this information using UE Capability Signaling. UE Capability Signaling is signaling for notifying the base station 101 of the UE's capabilities, and is used after an RRC connection is established with the base station 101. Therefore, the signaling can include more information than, for example, when reporting or notifying using a control channel or the like. For example, the control device 131 may notify the base station 101 of various information about the reflecting devices 120 described above by using UE Capability Signaling. Furthermore, by using UE Capability Signaling, an acknowledgment indicating that the base station 131 has received information is notified, thereby enabling highly reliable control. In this case, a new field may be defined in UE Capability Signaling for the control device 131 to notify information. The base station 101 extracts information included in the UE Capability Signaling and identifies the number of reflecting devices 120 connected to the control device 131 and information about each reflecting device 120. The control device 131 may also notify the above information using random access procedure message 1 or message 3. For example, when using random access procedure message 1, the control device 131 may report information such as the number of reflecting devices 120 to the base station 101 by utilizing the fact that multiple preamble patterns are prepared. For example, by determining in advance preamble patterns according to the number of reflecting devices 120 notified by the control device 131, the control device 131 selects a pattern according to the number of reflecting devices 120 notified and performs random access. The base station 101 identifies the number of reflecting devices 120 based on the pattern selected by the control device 131. A combination of multiple preamble patterns may be used to notify the number of reflecting devices 120.The base station 101 identifies the number of reflecting devices 120 based on the preamble pattern used by the control device 131 in the random access channel. On the other hand, when using the random access procedure message 3, a new field may be defined for the control device 131 to notify information. Alternatively, some fields in an existing message may be diverted for notification by the control device 131. The base station 101 identifies the number of reflecting devices 120 and information about each reflecting device 120 from fields in the message. The control device 131 may notify the above information using uplink control information (UCI). In this case, a new UCI format may be defined for notification by the control device 131. Alternatively, an existing UCI format may be diverted for notification by the control device 131. For example, a field of a predetermined number of bits may be provided in the UCI to indicate the number of reflecting devices 120. The base station 101 extracts the number of reflecting devices 120 and information about each reflecting device 120 from the UCI. Alternatively, the above information may be notified at the IRS protocol layer. The base station 101 receives a message of the IRS protocol layer and acquires information contained in the message. By defining the protocol layer for the IRS, it becomes possible to use a message format suitable for notification by the control device 131. Note that the above notification methods may be used in combination with each other.

[0042] (Processing Example 2) In Processing Example 1, the base station 101 instructs the reflection patterns of each of the multiple reflecting devices 120 connected to the control device 131, and, for example, even when the terminal 110 in a first extended area formed by a first reflecting device moves outside the first extended area, the base station 101 can maintain communication with the terminal 110. In this example, the base station 101 forms a new third extended area in the direction of movement of the terminal 110 based on a transition from a first state in which the base station 101 communicates with the terminal 110 via a first reflecting device to a second state in which the base station 101 communicates with the terminal 110 via a second reflecting device. That is, for example, in the wireless communication network shown in FIG. 6 , assume that the terminal 111 transitions from a first state in which the terminal 111 communicates with the base station 101 via the reflecting device 122 in an extended area a171 formed by the reflecting device 122 to a second state in which the terminal 111 communicates with the base station 101 via the reflecting device 121. At this time, if the terminal 111 moves further, there is a possibility that it will move outside the extended area (not shown) formed by the reflection device 121. Therefore, in this example, the area formed by the reflection device 122 is changed from extended area a 171 to extended area b 172, thereby maintaining communication between the base station 101 and the terminal 111. This makes it possible to further improve the continuity of communication between the base station 101 and the terminal 111. In FIG. 6, the solid arrow 181 indicates an example of the movement path of the terminal 111.

[0043] FIG. 7 shows an example of a processing flow executed when the base station 101 determines whether to change the reflection pattern of the reflecting device 122. This processing can be executed when a connection between the base station 101 and the control device 131 is established and the base station 101 and the terminal 111 are communicating in an extended area formed by each of the plurality of reflecting devices 120 connected to the control device 131. At this time, the reflecting device 122 used for communication between the base station 101 and the terminal 111 is referred to as a first reflecting device, and the extended area formed by this first reflecting device is referred to as a first extended area. Furthermore, another reflecting device 121 connected to the control device 131 but not used for communication between the base station 101 and the terminal 111 is referred to as a second reflecting device, and the extended area formed by this second reflecting device is referred to as a second extended area. Note that this example will be described using the operation of the base station 101 and the like in the configuration of FIG. 6 , but the operation of this example is not limited to the configuration of FIG. 6 and can be applied to any configuration.

[0044] First, the base station 101 identifies the location of the terminal 111 (S701). Any method may be used for the base station 101 to identify the location of the terminal 111. For example, if the base station 101 can obtain location information of the terminal 111 from the terminal 111, the base station 101 may obtain that information. Furthermore, if the location information of the terminal 111 is managed in the wireless communication system, the base station 101 may obtain that information. Based on the identified location of the terminal 111, the base station 101 determines whether the terminal 111 is within the geographic range of the first expanded area (S702). That is, if the terminal 111 is within the first expanded area (NO in S702), the base station 101 maintains the current reflection pattern and continues to check the location of the terminal 111. On the other hand, if the base station 101 determines that the terminal 111 has moved from the first expanded area to the second expanded area (YES in S702), the base station 101 performs processing to change the reflection pattern of the first reflecting device 122. That is, when the base station 101 finds that it is no longer necessary to maintain the first extended area due to the movement of the terminal 111, it changes the reflection pattern of the first reflecting device so as to form a new third extended area in anticipation of the movement of the terminal 111. For example, the base station 101 may determine the reflection pattern of the first reflecting device 122 so as to form a third extended area that is at least partially different from the second extended area and adjacent to the second extended area (S703). Then, the base station 101 instructs the control device 131 to control the reflection pattern of the first reflecting device 122 using the determined reflection pattern (S704).

[0045] The base station 101 may change the reflection pattern of the first reflector 122 when a predetermined condition is satisfied after the terminal 111 moves to the second expansion area. For example, the terminal 111 may move from the first expansion area to the second expansion area and then move back to the first expansion area. In this case, the base station 101 may maintain the reflection pattern of the first reflector 122 even after the terminal 111 moves to the second expansion area, thereby enabling the terminal 111 to continue communication. For example, the base station 101 may change the reflection pattern of the first reflector 122 when the terminal 111 moves beyond a predetermined distance from the edge of the first expansion area, determining that the predetermined condition is satisfied. Furthermore, the base station 101 may change the reflection pattern of the first reflector 122 when the terminal 111 moves in the second expansion area in a direction away from the first expansion area for a predetermined period or a predetermined distance, determining that the predetermined condition is satisfied.

[0046] FIG. 8 shows an example of a sequence in which the base station 101 sets the reflection patterns of the reflectors 121 and 122 via the control device 131. Processes that operate similarly to those in FIG. 5 are assigned the same reference numerals, and descriptions thereof will be omitted. That is, in steps S501 to S509, the base station 101 establishes a connection with the control device 131, determines the reflection patterns of the first reflector 122 and the second reflector 121, and sets the first reflector 122 and the second reflector 121 via the control device 131. At this time, it is assumed that the terminal 111 is located in a first extended area formed by the first reflector 122. When the base station 101 detects that the terminal 111 has moved from the first extended area to the second extended area formed by the second reflector 121 (S801), it changes the reflection pattern of the first reflector 122. For example, the base station 101 may determine the reflection pattern of the first reflector 122 so as to form a third expansion area that is at least partially different from the second expansion area and adjacent to the second expansion area (S802). The base station 101 may issue an instruction to the control device 131 including the determined reflection pattern (S803). For example, the base station 101 may issue an instruction including information identifying the first reflector 122 whose reflection pattern should be changed and information specifying the reflection pattern to be set. Based on the instruction from the base station 101, the control device 131 identifies the reflector whose reflection pattern should be changed and the reflection pattern to be set (S804), and controls the reflection pattern of the first reflector 122 (S805). In this way, in this example, when the base station 101 detects, based on the location information of the terminal 111, that the terminal 111 has moved from the first expansion area to the second expansion area, the base station 101 changes the reflection pattern of the first reflector 122 that forms the first expansion area to form the third expansion area. This makes it possible to maintain communication between the base station 101 and the terminal 111 even when the terminal 111 continues to move and moves out of the second extended area.

[0047] Note that if the control device 131 is connected to three or more reflecting devices 120, the base station 101 may form a new expansion area using a third reflecting device. FIG. 9 shows an example of a configuration in which reflecting devices 121 to 123 are connected to the control device 131. In FIG. 9, the base station 101 is communicating with a terminal 111 located in a first expansion area 173 formed by reflection from the reflecting device 122. In this case, the base station 101 may control the reflection patterns of the second reflecting device 121 and the third reflecting device 123 so as to form a second expansion area 174 and a third expansion area 175 adjacent to the first expansion area. When the base station 101 detects that the terminal 111 has moved from the first expansion area 173 to the second expansion area 174, it may form a new fourth expansion area 176 by changing the reflection pattern of the third reflecting device 123 while maintaining the reflection pattern of the first reflecting device 122. That is, when the terminal 111 is in the first expansion area 173, the base station 101 can form the second expansion area 174 or the third expansion area 175 using the reflecting device 121 and the reflecting device 123 so that communication between the base station 101 and the terminal 111 can be maintained regardless of whether the terminal 111 moves to either of the second expansion area 174 and the third expansion area 175. Then, based on the terminal 111 moving to the second expansion area 174, the base station 101 determines that the terminal 111 is unlikely to move to the third expansion area 175 soon and that the terminal 111 is likely to move from the second expansion area 174 toward a geographical range corresponding to the fourth expansion area 176, and controls the reflection pattern so that the third reflecting device 123 forms the fourth expansion area 176. In this case, even if the terminal 111 moves from the second expansion area 174 to the first expansion area 173, the first expansion area 173 is maintained by the first reflecting device 122, so that communication between the base station 101 and the terminal 111 can be maintained. In this way, the base station 101 can control the reflection pattern of any of the reflecting devices 120 connected to the control device 131 so that a new expansion area is formed along the direction of travel of the terminal 111 on the movement path of the terminal 111. The new expansion area may be at least partially different from the expansion area in which the terminal 111 is located and may be adjacent to that expansion area.With this configuration, it is possible to improve the continuity of communication between the base station 101 and the terminal 111 even in a blind area.

[0048] As described above, according to this embodiment, the base station 101 selects the reflection patterns of each of the multiple reflecting devices 120 connected to the control device 131 so as to form a first extended area including the geographical location of the terminal 110 and a second extended area that is at least partially different from the first extended area and adjacent to the first extended area, and notifies the control device 131 of the selected pattern. The control device 131 controls the reflection patterns of each of the multiple reflecting devices connected to the base station 101 based on instructions from the base station 101. With this configuration, even when the terminal 110 moves outside the range of the first extended area formed by the first reflecting device in a blind zone, communication between the base station 101 and the terminal 110 can be maintained in the second extended area formed by the second reflecting device. This expands the geographical area in which the base station 101 and the communication terminal 110 can communicate, even in a blind zone, enabling efficient measures to be taken against blind zones. This makes it possible to contribute to Goal 9 of the United Nations' Sustainable Development Goals (SDGs), "Build resilient infrastructure, promote sustainable industrialization and foster innovation."

[0049] 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.

[0050] This application claims priority based on Japanese Patent Application No. 2024-049213, filed March 26, 2024, the entire contents of which are incorporated herein by reference.

Claims

1. A base station device capable of communicating with a terminal device via a reflector that reflects radio waves, wherein an area in which the terminal device can communicate with the base station device is formed by reflection based on the reflection pattern of the reflector, a plurality of the reflectors are connected to one control device that controls the reflection pattern of the reflectors, the base station device having: selection means for selecting a first reflection pattern to be set on the first reflector so that a first area formed by reflection from a first reflector included in the plurality of reflectors includes a geographical location of the terminal device, and selecting a second reflection pattern to be set on the second reflector so that a second area formed by reflection from a second reflector different from the first reflector included in the plurality of reflectors is at least partially different from the first area and adjacent to the first area; and instruction means for issuing instructions to the control device including specific information that can identify the first reflection pattern and the second reflection pattern.

2. The base station device according to claim 1, further comprising an acquisition means for acquiring information capable of identifying the position of the terminal device, wherein the selection means selects the first reflection pattern according to the position of the terminal device.

3. The base station device according to claim 2, wherein the information that can identify the position of the terminal device includes information that can estimate the movement path of the terminal device, and the selection means selects the second reflection pattern so that the first area is at least partially different from the second area on the movement path.

4. The base station device described in claim 3, wherein the selection means, based on the transition from a first state in which the base station device is communicating with the terminal device via reflection from the first reflector to a second state in which the base station device is communicating with the terminal device via reflection from the second reflector, selects a third reflection pattern that is at least partially different from the second area on the movement path of the terminal device and forms a third area adjacent to the second area, and the instruction means is instruction means that issues an instruction to the control device including information that can identify the third reflection pattern.

5. The base station device according to claim 1, further comprising a beam shaping means for shaping a beam used by the base station device to transmit radio waves, the shaping means shaping the beam so as to increase the strength of the radio waves directed toward the reflecting device that forms the area in which the terminal device is present.

6. The base station device according to claim 1, wherein the instruction means issues an instruction that further includes identification information for identifying the reflector device to which each of the reflection patterns specified by the specification information should be set.

7. The base station device according to claim 1, wherein the instruction means, when notifying a reflection pattern to all of the plurality of reflection devices, issues the instruction including the specific information arranged in a predetermined order that enables identification of the reflection device to which each of the reflection patterns should be set, but does not include information that identifies each of the reflection devices.

8. The base station device according to claim 1, wherein the instruction means issues the instruction to the control device using at least one of a Radio Resource Control (RRC) message in the cellular communication standard of the Third Generation Partnership Project (3GPP), downlink control information or a Medium Access Control (MAC) subheader, and an Intelligent Reflecting Surface protocol.

9. A control device that controls the reflection pattern of a reflector that reflects radio waves, wherein an area is formed by reflection based on the reflection pattern of the reflector, whereby a terminal device can communicate with a base station device, and a plurality of the reflectors are connected to the control device, and the control device has: a receiving means that receives instructions from the base station device, the receiving means including specific information that can identify the reflection pattern to be set on each of the plurality of reflectors; and a control means that controls the reflection pattern of the reflectors in accordance with the instructions, the instructions including the specific information associated with a first reflection pattern to be set on the first reflector so that a first area formed by reflection from a first reflector included in the plurality of reflectors includes a geographical location of the terminal device, and a second reflection pattern to be set on the second reflector so that a second area formed by reflection from a second reflector different from the first reflector included in the plurality of reflectors is at least partially different from the first area and adjacent to the first area.

10. A control method executed by a base station device capable of communicating with a terminal device via a reflector that reflects radio waves, wherein an area in which the terminal device can communicate with the base station device is formed by reflection based on the reflection pattern of the reflector, a plurality of the reflectors are connected to one control device that controls the reflection pattern of the reflectors, the control method comprising: selecting a first reflection pattern to be set on the first reflector so that a first area formed by reflection from a first reflector included in the plurality of reflectors includes a geographical location of the terminal device; selecting a second reflection pattern to be set on the second reflector so that a second area formed by reflection from a second reflector different from the first reflector included in the plurality of reflectors is at least partially different from the first area and adjacent to the first area; and issuing an instruction to the control device including specific information that can identify the first reflection pattern and the second reflection pattern.

11. A control method executed by a control device that controls the reflection pattern of a reflector that reflects radio waves, wherein an area in which a terminal device can communicate with a base station device is formed by reflection based on the reflection pattern of the reflector, a plurality of the reflectors are connected to the control device, the control method includes: receiving instructions from the base station device including specific information that can identify the reflection pattern to be set on each of the plurality of reflectors; and controlling the reflection pattern of the reflectors in accordance with the instructions, wherein the instructions include the specific information associated with a first reflection pattern to be set on the first reflector so that a first area formed by reflection from a first reflector included in the plurality of reflectors includes a geographical location of the terminal device, and a second reflection pattern to be set on the second reflector so that a second area formed by reflection from a second reflector different from the first reflector included in the plurality of reflectors is at least partially different from the first area and adjacent to the first area.

12. A program for causing a computer to function as each of the means possessed by the base station device according to any one of claims 1 to 8.

13. A program for causing a computer to function as each of the means possessed by the control device according to claim 9.

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