WO2024189841A1 - Wireless communication system, control device, power source control method, and program - Google Patents

Abstract

A wireless communication system comprising a plurality of base station devices and a control device. The control device comprises an acquisition unit and a control unit. The acquisition unit acquires terminal position information indicating information on a position where a terminal device is present. The control unit selects a base station device to be subjected to power supply control for changing power consumption on the basis of the position of the terminal device indicated by the terminal position information and the position of each of the plurality of base station devices, and instructs the selected base station device to control power supply. The base station device comprises a wireless communication unit, a power supply unit, and a power supply control unit. The wireless communication unit communicates wirelessly with the terminal device. The power supply unit supplies power to at least the wireless communication unit. The power supply control unit performs control so as to change power supplied from the power supply unit on the basis of an instruction from the control device.

Description

Wireless communication system, control device, power supply control method and program

The present invention relates to a wireless communication system, a control device, a power supply control method, and a program.

A wireless communication system generally consists of a base station device and a terminal device. In particular, mobile communications such as LTE (Long Term Evolution) and 5G (fifth generation mobile communication system) that are deployed in a certain area, and wireless LANs (Local Area Networks) deployed in commercial facilities, etc., are composed of multiple base station devices 901 that cover area A that provides the service, and multiple terminal devices 902 that connect to the base station devices 901, as shown in FIG. 27. If the power of the base station device 901 is OFF, the terminal device 902 cannot send a connection request to the base station device 901. In other words, the area B covered by the base station device 901 becomes a situation where the service cannot be provided in a spot manner (coverage hole). Therefore, in a general wireless communication system, the power of each base station device 901 is always ON, and is generally not turned OFF, even if the terminal device 902 is not present. Since it is not known which base station device the terminal device will be connected to, the base station device is required to be constantly powered on and waiting for the terminal device. This poses the problem of increased power consumption by the base station device.

5G and other wireless communication systems are operated by combining multiple frequency bands. In such wireless communication systems, as shown in FIG. 28, base station devices 903 are arranged so that areas B covered by each of the base station devices 903 overlap, and the capacity of wireless communication provided as a service may be improved. Such a network is generally called a heterogeneous network. Although heterogeneous means different, in this specification, a wireless communication system in which base station devices are arranged so that multiple areas B overlap, regardless of whether the wireless systems corresponding to the overlapping base station devices are different (using different wireless methods and frequencies) or the same (using the same wireless method and frequency), is broadly called a heterogeneous network. In such a heterogeneous network, as shown in FIG. 29, the power supply of base station devices 903 that are determined to be unnecessary can be turned off based on the number of terminal devices 904 connected to each base station device 903 and the communication volume, and such control is being considered (for example, see Non-Patent Document 1). This control makes it possible to reduce the power consumption of the base station device 903. However, like the wireless communication system shown in FIG. 27, in this wireless communication system, the power of the minimum number of base station devices 903 required to cover the entire area A, as shown in FIG. 30, must be kept on at all times, and the power of these devices cannot be reduced.

Also, as shown in FIG. 31, a control device 906 may be provided to control the power supply of each base station device 905, and as shown in FIG. 32, the control device 906 may turn off the power supply of the base station device 905 during a time period when the terminal device 907 is unlikely to be connected. In this case, even if the terminal device 907 attempts to connect during that time period, it will not be able to connect to the base station device 905.

F. Han, S. Zhao, L. Zhang and J. Wu, “Survey of Strategies for Switching Off Base Stations in Heterogeneous Networks for Greener 5G Systems,” in IEEE Access, vol. 4, pp. 4959-4973, 2016, doi: 10.1109/ACCESS.2016.2598813.

In a typical wireless communication system, turning off the power of base station equipment directly leads to the occurrence of coverage holes. Furthermore, even if some base station equipment in a heterogeneous network is powered off, the minimum number of base station equipment required to cover the area to prevent the occurrence of coverage holes must be kept powered on at all times. This makes it difficult to efficiently reduce the power consumption of base station equipment.

In view of the above, the present invention aims to provide a wireless communication system, a control device, a power supply control method, and a program that can reduce the power consumption of a base station device while reducing the number of situations in which a terminal device cannot connect to the base station device.

One aspect of the present invention is a wireless communication system having a plurality of base station devices and a control device, the control device comprising: an acquisition unit that acquires terminal location information indicating information regarding the location of a terminal device; and a control unit that selects, from among the plurality of base station devices, a base station device that is to be subject to power control to change power consumption based on the location of the terminal device indicated by the terminal location information and the respective locations of the plurality of base station devices, and instructs the selected base station device to perform the power control; the base station device comprises a wireless communication unit that wirelessly communicates with terminal devices present within its own wireless communication area, a power supply unit that supplies power to at least the wireless communication unit, and a power supply control unit that controls the power supplied from the power supply unit to be changed based on the instruction from the control device.

One aspect of the present invention is a control device that includes an acquisition unit that acquires terminal location information indicating information related to the location where a terminal device is located, and a control unit that selects, from among a plurality of base station devices that wirelessly communicate with a terminal device present within the wireless communication area of the control device, a base station device that is to be subject to power control to change power consumption based on the location of the terminal device indicated by the terminal location information and the respective locations of the plurality of base station devices, and instructs the selected base station device to perform the power control.

One aspect of the present invention is a power control method having an acquisition step of acquiring terminal location information indicating information regarding the location where a terminal device is located, and a control step of selecting, from among a plurality of base station devices that wirelessly communicate with a terminal device present within the wireless communication area of the own device, a base station device that is to be subject to power control to change power consumption based on the location of the terminal device indicated by the terminal location information and the respective locations of the plurality of base station devices, and instructing the selected base station device to perform the power control.

One aspect of the present invention is a program for causing a computer to execute an acquisition step of acquiring terminal location information indicating information regarding the location where a terminal device is located, and a control step of selecting, from among a plurality of base station devices that wirelessly communicate with a terminal device present within the wireless communication area of the own device, a base station device that is to be subject to power control to change power consumption based on the location of the terminal device indicated by the terminal location information and the respective locations of the plurality of base station devices, and instructing the selected base station device to perform the power control.

This invention makes it possible to reduce the power consumption of base station devices while reducing the number of situations in which terminal devices are unable to connect to base station devices.

1 is a configuration diagram of a wireless communication system according to a first embodiment. FIG. 2 is a diagram illustrating an example of power supply control according to the first embodiment. FIG. 2 is a block diagram showing a configuration of a base station device according to the first embodiment. 1 is a block diagram showing a configuration of a control device according to a first embodiment; FIG. 4 is a flowchart showing an area end power supply control process of the control device according to the first embodiment. FIG. 4 is a flow diagram showing a terminal connection notification process of the base station device according to the first embodiment. FIG. 11 is a flow diagram showing a terminal disconnection notification process of the base station device according to the first embodiment. FIG. 4 is a flow diagram showing a terminal connection notification receiving process of the control device according to the first embodiment. FIG. 4 is a flow diagram showing a terminal disconnection notification receiving process of the control device according to the first embodiment. FIG. 11 is a configuration diagram of a wireless communication system according to a second embodiment. FIG. 11 is a configuration diagram of a wireless communication system according to a second embodiment. FIG. 11 is a block diagram showing a configuration of a base station device according to a second embodiment. FIG. 11 is a block diagram showing a configuration of a control device according to a second embodiment. FIG. 11 is a flow chart showing an area entry notification receiving process of the control device according to the second embodiment. FIG. 11 is a flow chart showing a terminal exit notification receiving process of the control device according to the second embodiment. FIG. 11 is a diagram illustrating an example of a configuration of a wireless communication system according to a second embodiment. FIG. 11 is a diagram illustrating an example of a configuration of a wireless communication system according to a second embodiment. FIG. 1 is a conceptual diagram of a wireless communication system that uses beamforming in the millimeter wave band. FIG. 11 is a configuration diagram of a wireless communication system according to a third embodiment. FIG. 13 is a block diagram showing a configuration of a base station device according to a third embodiment. FIG. 11 is a block diagram showing a configuration of a control device according to a third embodiment. FIG. 11 is a flow diagram showing an operation of a base station device according to the third embodiment. FIG. 11 is a flow chart showing the operation of the control device according to the third embodiment. FIG. 13 is a diagram illustrating an example of a power-on determination area according to the third embodiment. FIG. 11 is a diagram illustrating an example of the operation of the control device according to the third embodiment. FIG. 2 is a device configuration diagram showing an example of a hardware configuration of a control device according to the first to third embodiments. FIG. 1 illustrates a conventional wireless communication system. FIG. 1 illustrates a conventional wireless communication system. FIG. 1 illustrates a conventional wireless communication system. FIG. 1 illustrates a conventional wireless communication system. FIG. 1 illustrates a conventional wireless communication system. FIG. 1 illustrates a conventional wireless communication system.

Below, an embodiment of the present invention will be described in detail with reference to the drawings. In all drawings used to explain the embodiment, the same reference numerals will be used for parts having the same functions, and repeated explanations will be omitted.

[First embodiment]
FIG. 1 is a diagram showing an example of the configuration of a wireless communication system 10 in the first embodiment of the present invention. The wireless communication system 10 has a plurality of base station devices 20 and a control device 30. Each base station device 20 is connected to the control device 30. The N base station devices 20 are also referred to as base station devices 20-1 to 20-N. The N base station devices 20 are generally fixedly installed so as to cover a specific area. In FIG. 1, an area A is covered in a planar manner by the coverage area B of each base station device 20. In this case, it is expected that the positional relationship between the N base station devices 20 is constant. Also, even in the case of a base station device 20 installed in a train, which is called a moving cell, the positional relationship between the base station devices 20 generally does not change. For this reason, it is possible to turn off and on the power of each base station device 20 based on the positional relationship between the base station devices 20.

Specifically, as shown in FIG. 1, the power of the base station device 20 at the edge of area A is turned ON, and the power of the base station device 20 that is not at the edge of the area is turned OFF. Note that the power of some of the base station devices 20 that are not at the edge of the area may be ON. By keeping the power of at least the base station devices 20 at the edge of the area ON, a terminal device 40 that enters from outside area A can always connect to a base station device 20 when it enters area A.

　Base station device 20-n (n is an integer between 1 and N) that receives a connection request from terminal device 40 transmits connection information to control device 30 indicating that terminal device 40 has been connected. Based on the connection information from base station device 20-n, control device 30 identifies other base station devices 20 adjacent to base station device 20-n. Other base station devices 20 adjacent to base station device 20 are referred to as adjacent base station devices 20. Control device 30 turns on the power of adjacent base station device 20. When terminal device 40 moves to coverage area B of base station device 20-m (m ≠ n, m is an integer between 1 and N), which is one of the adjacent base station devices 20, it transmits a connection request to base station device 20-m to change the communication destination. Base station device 20-m that receives a connection request transmits connection information to control device 30. By repeating this process, terminal device 40 can continue communication within area A.

Furthermore, when the number of connections of terminal devices 40 to the base station device 20 becomes zero, each base station device 20 transmits connection information indicating that to the control device 30. When the control device 30 receives connection information indicating that the number of connections is zero from any of the base station devices 20, it determines, for each base station device 20, whether a terminal device 40 is connected to that base station device 20 and whether a terminal device 40 is connected to an adjacent base station device 20 of that base station device 20. When a terminal device 40 is not connected to either the base station device 20-n or the adjacent base station device 20 of that base station device 20-n, the control device 30 instructs the base station device 20-n to turn off its power. This makes it possible to efficiently reduce the power consumption of the base station device 20 while suppressing the occurrence of coverage holes.

In the example of FIG. 1, all base station devices 20 at the edge of the area are powered ON, assuming that there is a possibility that terminal devices 40 may enter area A from all directions. However, in cases where it is expected that terminal devices 40 will enter from a certain direction and not from other directions, such as when providing services to trains or road vehicles, the power of base station devices 20 whose coverage area B includes the location where terminal devices 40 will enter from outside area A can be turned ON, and the power of base station devices 20 in locations where terminal devices 40 will not enter can be turned OFF.

FIG. 2 is a diagram showing an example of power supply control when a vehicle 45 equipped with a terminal device 40 travels in a fixed direction. In FIG. 2, base station devices 20 are extracted and shown whose coverage area B includes road R. The extracted base station devices 20 are base station devices 20-1 to 20-5, from left to right. Base station device 20-1 and base station device 20-5 are at the edge of the area. A vehicle 45 equipped with a terminal device 40 travels on a one-way road R from left to right, and does not travel in the opposite direction. In this case, if the power supply of base station device 20-1 at the edge of the area into which the vehicle 45 enters is turned ON, the power supply of base station devices 20-2 to 20-5 can be turned ON in accordance with the movement of the terminal device 40 without causing a coverage hole, even if the power supply of base station devices 20-2 to 20-5 is OFF.

FIG. 3 is a block diagram showing the configuration of the base station device 20. In FIG. 3, only the functional blocks related to this embodiment are shown. The base station device 20 includes a wireless communication unit 201, a communication unit 202, a power supply control unit 203, a power supply unit 204, and a notification unit 205.

The wireless communication unit 201 wirelessly communicates with the terminal device 40 in the coverage area B. The wireless communication unit 201 has an antenna for transmitting and receiving wireless signals. The communication unit 202 communicates with the control device 30. The power supply control unit 203 switches the power supply unit 204 between the power ON state and the power OFF state in accordance with instructions from the control device 30. As a result, the power supply control unit 203 controls the amount of power supplied from the power supply unit 204 to be changed. The power supply unit 204 supplies power to each unit in the base station device 20. When the power supply unit 204 is ON, it supplies power to each component including the wireless communication unit 201. When the power supply unit 204 is OFF, the power supply unit 204 reduces or stops the supply of power to some components including the wireless communication unit 201 compared to when the power supply is ON. Even when the power supply unit 204 is OFF, it supplies power to at least the communication unit 202 and the power supply control unit 203 so that the power supply unit 204 can be controlled in accordance with instructions from the control device 30.

The notification unit 205 notifies the control device 30 of connection information indicating the start and end of a connection with the terminal device 40 in the wireless communication unit 201. The notification unit 205 may also notify the control device 30 of connection information including the number of connected terminals. The number of connected terminals is the number of terminal devices 40 connected to the control device. The connection information indicates whether or not the terminal device 40 is present within the coverage area B of the control device. In other words, the connection information corresponds to information indicating the position of the terminal device 40.

FIG. 4 is a block diagram showing the configuration of the control device 30. In FIG. 4, only the functional blocks related to this embodiment are shown. The control device 30 can be realized, for example, by a computer device. The control device 30 includes a communication unit 301, a storage unit 302, a notification receiving unit 303, a control unit 304, and an update unit 305.

The communication unit 301 communicates with each base station device 20. The memory unit 302 stores various information including facility information, connection management information, and power supply information. The facility information is information that can be acquired about adjacent base station devices 20 of each base station device 20 and about base station devices 20 at the edge of the area. The connection management information is information indicating whether or not a terminal device 40 is connected to each base station device 20. The connection management information may be information indicating the number of terminal devices 40 connected to each base station device 20. The power supply information is information indicating whether each base station device 20 is in a power OFF state or a power ON state.

The notification receiving unit 303 receives connection information from the base station device 20. The control unit 304 turns on the power of the base station device 20 whose coverage area B is the area edge. The control unit 304 determines the base station device 20 to be instructed to turn the power OFF or ON based on the connection information that the notification receiving unit 303 received from the base station device 20 and the connection management information and facility information stored in the storage unit 302. The control unit 304 instructs the base station device 20 to turn the power ON or OFF according to the determination.

The update unit 305 updates the connection management information stored in the storage unit 302 based on the connection information from the base station device 20 received by the notification receiving unit 303. The update unit 305 also updates the power information based on an instruction to the base station device 20 to turn the power on or off.

The "adjacent" base station device 20 and the "area edge" base station device 20 may be set individually in the control device 30. For example, in the facility information stored in the memory unit 302 of the control device 30, one or more other base station devices 20 that are to be turned on when a terminal device 40 is connected to the base station device 20-n may be set for each base station device 20-n. In this case, the other base station devices 20 that are to be turned on are defined as adjacent base station devices 20 of the base station device 20-n. When the control unit 304 of the control device 30 receives connection information from the base station device 20-n indicating that a terminal device 40 has been connected, it instructs the adjacent base station device 20 obtained by referring to the facility information to turn on the power. In addition, the control unit 304 does not need to instruct the adjacent base station device 20 that is already in a power-on state to turn on the power. In addition, information on the base station device 20 that is to be always turned on may be set in the facility information stored in the memory unit 302 of the control device 30. In this case, the base station device 20 that is always powered on is defined as the base station device 20 at the edge of the area.

Furthermore, "adjacent" base station devices 20 and "area edge" base station devices 20 may be automatically selected and determined based on the position information of each base station device 20. That is, the position information and cover area B of each base station device 20 are set in the equipment information stored in the memory unit 302 of the control device 30. The position information and cover area B may be expressed in absolute coordinates or relative coordinates. Alternatively, each base station device 20 may store its own position information and equipment information indicating the cover area B, and transmit the equipment information to the control device 30. The control device 30 grasps the positional relationship between the cover areas B of each base station device 20 based on the equipment information.

Then, the control unit 304 of the control device 30 determines that the base station devices 20 to which the terminal device 40 may directly handover are adjacent based on the positional relationship of the cover areas B. When the control unit 304 of the control device 30 receives connection information indicating that the terminal device 40 is connected to a certain base station device 20-n, it transmits a power-on instruction to the adjacent base station device 20 of the base station device 20-n. Furthermore, based on the positional relationship between the cover areas B, the control unit 304 of the control device 30 may define the base station device 20 whose outer edge is the cover area B as the area edge.

Furthermore, the memory unit 302 of the control device 30 may store area information indicating the physical location and topography of the service area A. Area information is, for example, floor information in a shopping mall, map information for roads and circuits, etc. The control unit 304 of the control device 30 may identify a location from which the terminal device 40 may enter the area A where the wireless communication system 10 provides service based on the area information, and may define the coverage area B including the identified location as the area edge.

Furthermore, the adjacent base station devices 20 may be in a multi-stage configuration. That is, the control device 30 also powers on the adjacent base station devices 20 of the base station device 20-n that is powered on. The base station device 20 adjacent to the adjacent base station device 20 is designated as the second adjacent base station device 20. When the control device 30 receives a connection notification indicating that the terminal device 40 has been connected to the base station device 20-n, it powers on the second adjacent base station device 20. This makes it possible to reduce the power consumption of the base station device 20 without causing a coverage hole, even when the terminal device 40 moves at high speed within the coverage area B of each base station device 20.

FIG. 5 is a flow diagram showing the area edge power control process of the control device 30. The control device 30 executes the process shown in FIG. 5 when starting service to area A. The control unit 304 of the control device 30 identifies the base station device 20 at the edge of the coverage area B based on the equipment information stored in the memory unit 302 (step S11). The control unit 304 instructs the identified base station device 20 at the edge of the area to turn on the power (step S12). The control unit 304 may refer to the power information stored in the memory unit 302 and select a base station device 20 that is powered off from among the base station devices 20 identified in step S11. The control unit 304 instructs the selected base station device 20 to turn on the power. The power control unit 203 of the base station device 20 instructed to turn on the power turns on the power unit 204. When the power on is completed, the power control unit 203 may transmit a response to the control device 30. The update unit 305 of the control device 30 updates the power information stored in the storage unit 302 when the power of the base station device 20 that instructed the power ON is ON. The update unit 305 may update the power information after receiving a response from the base station device 20 that instructed the power ON.

The power ON of the base station device 20 at the edge of the area may be instructed manually, for example, from an operation management system (not shown). When the power ON is completed, the power control unit 203 of the base station device 20 at the edge of the area transmits a notification to the control device 30. When the update unit 305 of the control device 30 receives the notification, it updates the power information.

FIG. 6 is a flow diagram showing terminal connection notification processing in a base station device 20 in a powered-on state. The wireless communication unit 201 of the base station device 20 receives a connection request from a terminal device 40 present in the coverage area of the base station device 20, and starts a wireless connection with the terminal device 40 (step S21). The notification unit 205 transmits a terminal connection notification to the control device 30 via the communication unit 202 (step S22). The terminal connection notification is an example of connection information indicating that a terminal device 40 has been connected to the control device. The notification unit 205 sets base station identification information, which is information that identifies the control device, in the terminal connection notification. The notification unit 205 may further set terminal identification information that identifies the connected terminal device 40 or the number of terminal devices 40 connected to the control device in the terminal connection notification.

FIG. 7 is a flow diagram showing terminal disconnection notification processing in a base station device 20 in a powered-on state. The wireless communication unit 201 of the base station device 20 disconnects the wireless connection with the terminal device 40 (step S31). The notification unit 205 transmits a terminal disconnection notification to the control device 30 via the communication unit 202 (step S32). The terminal disconnection notification is an example of connection information indicating that the terminal device 40 has been disconnected. The notification unit 205 sets the base station identification information of its own device in the terminal disconnection notification. The notification unit 205 may further set the terminal identification information of the disconnected terminal device 40 or the number of terminal devices 40 connected to its own device in the terminal connection notification.

FIG. 8 is a flow diagram showing the terminal connection notification reception process of the control device 30. The notification reception unit 303 of the control device 30 receives the terminal connection notification from the base station device 20 via the communication unit 301 (step S41). The notification reception unit 303 outputs the received terminal connection notification to the update unit 305. The update unit 305 identifies the connected terminal list stored in the memory unit 302 by the base station identification information read from the terminal connection notification. The connected terminal list is an example of connection management information. The connected terminal list is information that associates the base station identification information of each base station device 20 with the terminal identification information of the terminal device 40 connected to the base station device 20. The update unit 305 sets the terminal identification information read from the terminal connection notification in the identified connected terminal list (step S42).

Instead of the connected terminal list, connection management information that associates the base station identification information of each base station device 20 with the number of terminal connections may be used. The update unit 305 updates the number of terminal connections set in the connection management information in association with the base station identification information read from the terminal connection notification to a value incremented by 1.

The control unit 304 identifies the base station device 20 that is the source of the terminal connection notification by the base station identification information read from the terminal connection notification. The control unit 304 refers to the equipment information stored in the memory unit 302 and identifies the neighboring base station device 20 of the source base station device 20-n. The control unit 304 refers to the power information and determines whether the power of each identified neighboring base station device 20 is ON or OFF. The control unit 304 instructs the neighboring base station device 20 that is powered OFF to turn on the power (step S43). The power control unit 203 of the neighboring base station device 20 that received the power ON instruction sets the power unit 204 to the power ON state. When the power ON is completed, the power control unit 203 may transmit a response to the control device 30. The update unit 305 of the control device 30 updates the power information stored in the memory unit 302 to indicate that the power of the neighboring base station device 20 that was instructed to turn on is ON. The update unit 305 may update the power information after receiving a response from the neighboring base station device 20 that has been instructed to turn on the power.

FIG. 9 is a flow diagram showing the terminal disconnection notification reception process of the control device 30. The notification reception unit 303 of the control device 30 receives the terminal disconnection notification from the base station device 20 via the communication unit 301 (step S51). The notification reception unit 303 outputs the received terminal disconnection notification to the update unit 305. The update unit 305 identifies the connected terminal list by the base station identification information set in the terminal disconnection notification. The update unit 305 deletes the terminal identification information set in the received terminal connection notification from the identified connected terminal list (step S52).

In addition, when using connection management information that associates the base station identification information of each base station device 20 with the number of terminal connections instead of the connected terminal list, the update unit 305 updates the number of terminal connections set in the connection management information in association with the base station identification information read from the terminal disconnection notification to a value obtained by subtracting 1 from the number.

The control unit 304 refers to the connected terminal list stored in the memory unit 302 and selects all base station devices 20 to which no terminal device 40 is connected. The selected base station devices 20 are described as selected base station devices 20. The control unit 304 identifies adjacent base station devices 20 for each selected base station device 20 based on the equipment information stored in the memory unit 302. The control unit 304 refers to the connected terminal list and determines whether or not a terminal device 40 is connected to each identified adjacent base station device 20. The control unit 304 selects, among the selected base station devices 20, a selected base station device 20 to which no terminal device 40 is connected to any adjacent base station device 20 as a base station device 20 to be powered off. The control unit 304 instructs the selected base station device 20 to be powered off to power off (step S53).

The control unit 304 may not instruct the base station device 20, whose coverage area B is at the area edge, to turn off the power. Alternatively, the control unit 304 may perform the process of FIG. 5 after the process of step S53. The power control unit 203 of the base station device 20 instructed to turn off the power in step S53 sets the power unit 204 to a power-off state. When the power-off is complete, the power control unit 203 may transmit a response to the control device 30. The update unit 305 of the control device 30 updates the power information stored in the memory unit 302 to indicate that the power of the base station device 20 that instructed to turn off the power is off. The update unit 305 may update the power information after receiving a response from the base station device 20 that instructed to turn off the power.

This embodiment makes it possible to reduce the power consumption of the base station device 20 except for the edge terminal, while enabling connection from the terminal device 40 within the service area without coverage holes.

Second Embodiment
In the first embodiment, an example was shown in which the power of a base station device that is in a power-off state is turned on when a terminal device is connected to a base station device at the edge of the area. However, the approach of a terminal device to area A may be detected in cooperation with another system. The second embodiment will be described below, focusing on the differences from the first embodiment.

FIGS. 10 and 11 are diagrams showing an example of the configuration of a wireless communication system 11 according to the second embodiment. In FIG. 10 and FIG. 11, the same parts as those in the wireless communication system 10 of the first embodiment shown in FIG. 1 are given the same reference numerals, and their description will be omitted. The wireless communication system 11 has multiple base station devices 21 and a control device 31. Furthermore, an imaging device 50 is connected to the control device 31. Multiple imaging devices 50 may be connected to the control device 31. The imaging device 50 is an example of another system of the wireless communication system 11.

The imaging device 50 has a camera. The imaging device 50 captures an image of an area including area A, and detects the entry of a terminal device 40 based on the image data obtained by capturing the image. The control device 31 identifies a base station device 21 to which the terminal device 40 detected by the imaging device 50 may be connected, and turns on the power of the identified base station device 21, as shown in FIG. 10. Furthermore, when the control device 31 detects via the imaging device 50 that the terminal device 40 has left coverage area B, it turns off the power of the base station device 21 in that coverage area B. As a result, when all terminal devices 40 have left area A, as shown in FIG. 11, the power of all base station devices 21 is turned off.

12 is a block diagram showing the configuration of the base station device 21. In FIG. 12, only functional blocks related to this embodiment are shown. In the base station device 21 shown in FIG. 12, the same parts as those of the base station device 20 of the first embodiment shown in FIG. 3 are given the same reference numerals, and their description is omitted. The base station device 21 includes a wireless communication unit 201, a communication unit 202, a power supply control unit 203, a power supply unit 204, and a notification unit 211. The notification unit 211 receives an inquiry from the control device 31 and notifies the control device 31 whether or not the terminal device 40 is present within the coverage area B of the control device 31. For example, when the wireless communication unit 201 is communicating with the terminal device 40, the notification unit 211 determines that the terminal device 40 is present within the coverage area B, and when the wireless communication unit 201 is not communicating with the terminal device 40, the notification unit 211 determines that the terminal device 40 is not present within the coverage area B.

FIG. 13 is a block diagram showing the configuration of the control device 31. In FIG. 13, only the functional blocks related to this embodiment are shown. In the control device 31 shown in FIG. 13, the same parts as those in the control device 30 of the first embodiment shown in FIG. 4 are given the same reference numerals, and their description will be omitted. The control device 31 includes a communication unit 301, a memory unit 311, a position acquisition unit 312, a control unit 313, and an update unit 314.

The storage unit 311 stores the same information as the storage unit 302 of the first embodiment. However, the storage unit 311 does not have to store connection management information. The location acquisition unit 312 analyzes image data captured by the imaging device 50 to obtain location information of the terminal device 40. The control unit 313 refers to the facility information stored in the storage unit 302, identifies the base station device 21 whose coverage area B includes the location of the terminal device 40, and instructs the identified base station device 21 to turn on the power. In addition, when the imaging device 50 detects that the terminal device 40 has left the area A or the coverage area B, the control unit 313 instructs the base station device 21 to turn off the power to the base station device 21 to which the terminal device 40 is not connected and to which the terminal device 40 is not connected to an adjacent base station device 21. The update unit 314 updates the power information based on the power on or power off instruction to the base station device 21.

FIG. 14 is a flow diagram showing the area entry notification reception process of the control device 31. The imaging device 50 captures the entire area A covered by the coverage area B of each base station device 21. When the imaging device 50 detects that the terminal device 40 has entered area A, it transmits an area entry notification containing the captured image data to the control device 31. The position acquisition unit 312 of the control device 31 receives the area entry notification via the communication unit 301 (step S61). The position acquisition unit 312 analyzes the image data read from the received area entry notification and estimates the position of the terminal device 40 that has entered area A (step S62).

The control unit 313 refers to the facility information stored in the memory unit 311 and identifies the base station device 21 in the coverage area B that includes the estimated position of the terminal device 40. The control unit 313 refers to the power information and determines whether the identified base station device 21 is powered on or off. If the control unit 313 determines that the power is off, it instructs the identified base station device 21 to turn on the power (step S63). The power control unit 203 of the base station device 21 that has been instructed to turn on the power sets the power unit 204 to the power on state. The update unit 314 of the control device 31 updates the power information stored in the memory unit 311 to indicate that the base station device 21 that was instructed to turn on the power is powered on.

In addition, the imaging device 50 may be provided with a position acquisition unit 312, and the control device 31 may receive information on the position of the terminal device 40 from the imaging device 50. In addition, in case the estimated position of the terminal device 40 is at the edge of the coverage area B of a certain base station device 21, the control unit 313 of the control device 31 may also identify a base station device 21 adjacent to the certain base station device 21, and instruct the identified base station device 21 to turn on the power.

FIG. 15 is a flow diagram showing the terminal exit notification reception process of the control device 31. When the imaging device 50 detects that the terminal device 40 has exited from area A, it transmits a terminal exit notification to the control device 31. The control unit 313 of the control device 31 receives the terminal exit notification via the communication unit 301 (step S71). The control unit 313 inquires of each base station device 21 about the presence or absence of the terminal device 40. The notification unit 211 of each base station device 21 notifies the control device 31 about whether or not the terminal device 40 is present within the coverage area B of the base station device itself. The control unit 313 of the control device 31 instructs the base station device 21 that has transmitted the notification that the terminal device 40 is not present to turn off the power (step S72). The update unit 314 updates the power information by indicating that the power of the base station device 21 that has been instructed to turn off the power is OFF.

In the above, the imaging device 50 is used to detect the position of the terminal device 40, but a positioning system such as GPS (Global Positioning System) may also be used. Figure 16 is a diagram showing an example of the configuration of a wireless communication system 12. The wireless communication system 12 shown in Figure 16 differs from the wireless communication system 11 shown in Figures 10 and 11 in that the control device 31 is connected to a positioning system 51 instead of the imaging device 50. The positioning system 51 is an external system to the wireless communication system 12. The positioning system 51 notifies the control device 31 of information on the position of each terminal device 40 that has been positioned. The position acquisition unit 312 of the control device 31 acquires the position information of the terminal device 40 based on the notification from the positioning system 51.

FIG. 17 is a diagram showing an example of the configuration of a wireless communication system 13. The wireless communication system 13 shown in FIG. 17 differs from the wireless communication system 12 shown in FIG. 10 and FIG. 11 in that the control device 31 is not connected to the imaging device 50, and receives location information of the terminal device 40 from the terminal device 40. The location information acquisition unit 41 of the terminal device 40 measures the location information of its own device using GPS or the like, and notifies the control device 31 by some method, such as a wireless communication system other than the wireless communication system 13. The location acquisition unit 312 of the control device 31 acquires the location information transmitted from the terminal device 40.

The position of the terminal device 40 may be determined by an infrared imaging device, an infrared sensor, or any other method. Pattern recognition or any other machine learning method may be applied to detect the terminal device 40. In this embodiment, it is expected that the position of the terminal device 40 can be detected with higher accuracy than in the first embodiment, which will enable further reduction in power consumption of the entire base station device.

[Third embodiment]
Wireless communication using millimeter waves and quasi-millimeter waves, which are classified as high frequency bands compared to conventional wireless communication, includes 3GPP (registered trademark) 5G NR and IEEE 802.11ad. These wireless communication have advantages such as being able to secure a wide bandwidth compared to conventional microwave bands, having a high directivity, and having little interference with other communications. Therefore, practical application is being promoted as a means for realizing high-capacity wireless communication (for example, see Reference 1).

(Reference 1) Takinami et al., "Standardization Trends and Elemental Technologies of Millimeter-Wave Wireless LAN Systems," IEICE Communications Society Magazine, Fall 2016, No. 38, p. 100-106

The amount of attenuation over distance in a wireless propagation path increases with frequency. For this reason, in millimeter wave communications, wireless station devices typically form directional beams (beamforming) toward the wireless station device of the communication partner to transmit wireless signals. It is also common for wireless station devices to form directional beams to receive signals.

FIG. 18 is a conceptual diagram of a typical wireless communication system that uses beamforming in the millimeter wave band. A wireless station device 61 can form multiple types of directional beams 611. In FIG. 18, the nine types of directional beams 611 are described as directional beams 611-1 to 611-9. The wireless station device 61 selects the beam with the maximum received power at the opposing wireless station device 65 from among these directional beams 611-1 to 611-9 (candidate beams). In IEEE 802.11ad, for example, beam selection is performed by a procedure called SLS (Sector Level Sweep) (see Reference 2, for example).

(Reference 2) IEEE, “Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications Amendment 3: Enhancements for Very High Throughput in the 60 GHz Band,” IEEE Std 802.11ad-2012, 2012

In SLS, first, the wireless station device 61 (initiator) that starts communication sequentially transmits signals using available directional beams 611 in a time-division manner. Hereinafter, the sequential transmission of signals using available beams is called beam sweep. At this time, the opposing wireless station device 65 (responder) receives the signal transmitted from the initiator using the beam with the maximum beam width and measures the received power. The responder may also transmit signals sequentially using available beams in the same way. Beam selection at the initiator is completed by sharing with the initiator the ID of the beam that provided the maximum received power at the responder.

In contrast, in 5G NR, multiple signal blocks called SS/PBCH (Synchronization Signal/Physical Broadcast CHannel) are transmitted sequentially in a time-division manner for each beam of the wireless base station device. The opposing wireless terminal station device reads these, measures which beam has the greatest received power, and feeds back the measurement result to the wireless base station device. This completes the initial beam selection.

In addition to the large attenuation due to distance in high frequency bands, if an obstruction is placed in the propagation path between the antenna of the transmitting radio station device and the antenna of the receiving radio station device, the propagation loss increases rapidly, making it difficult to transmit signals. For this reason, it is generally assumed that communications in high frequency bands are transmitted in a line-of-sight environment where there are no obstructions between the antenna of the transmitting radio station device and the antenna of the receiving radio station device. In such cases, the direction of the beam used by the radio station device directly indicates the direction of the communicating radio station device. In addition, if the radio station device has a distance estimation function using the round-trip time (RTT) of the signal as shown in Reference 3, for example, the position of the communicating radio station device can be estimated from that radio station device based on the signal itself that is communicated between the radio stations.

(Reference 3) Iwakuni et al., "Experimental evaluation of handover control using ranging function in high-frequency wireless communication system", B-5-56, 2020 IEICE Society Conference, Communications Lecture Proceedings 1, p. 256

Among wireless station devices, if the position of the terminal station device can be grasped, it is expected that advanced communication control based on the position can be realized. For example, as shown in Reference 4, by switching the base station device based on the position of the terminal station device, it becomes possible to stably switch the base station device without being affected by instantaneous power fluctuations. The position of the terminal station device can be determined by GNSS (Global Navigation Satellite System) such as GPS or GLONASS (Global Navigation Satellite System) if outdoors, and by methods such as BLE (Bluetooth Low Energy) and UWB (Ultra Wide Band) if indoors. However, in order to perform positioning using these methods, it is necessary to have a positioning unit such as a dedicated antenna or a positioning wireless receiving device. On the other hand, if terminal positioning based on the communication signal itself as described above is used, the base station device can estimate the position of the terminal device based on the signal itself used for communication with the terminal device without having to have them. The third embodiment reduces the power consumption of the base station device without complicating the wireless communication system by using terminal positioning based on the communication signals between the base station device and the terminal device itself.

(Reference 4) T. Iwakuni, D. Uchida, S. Wai and N. Kita, "Millimeter-Wave Handover Experiment in 293 km/h Mobility Environment using Position Estimated from Wireless Communication Signal," 2021 IEEE 94th Vehicular Technology Conference ( VTC2021-Fall), 2021, pp. 1-5, doi: 10.1109/VTC2021-Fall52928.2021.9625347.

FIG. 19 is a diagram showing an example of the configuration of a wireless communication system 15 according to the third embodiment. The wireless communication system 15 has multiple base station devices 25 and a control device 35. Each base station device 25 is connected to the control device 35. The N base station devices 25 are also referred to as base station devices 25-1 to 25-N. In addition, other base station devices 25 adjacent to a base station device 25 are referred to as adjacent base station devices 25.

The operation of the wireless communication system 15 will now be described. The control device 35, for example, performs the process shown in FIG. 5 to turn on the power of the base station device 25 at the edge of the area and to keep the power of the other base station devices 25 off. When a terminal device 40 is connected to the base station device 25 at the edge of the area, the base station device 25 wirelessly communicates with the terminal device 40 by directing a beam 26 at the terminal device 40. The base station device 25 locates the position of the terminal device 40 by terminal positioning based on the communication signal itself. The base station device 25 transmits positioning information indicating the position of the terminal device 40 obtained by positioning to the control device 35.

The control device 35 determines the location of the terminal device 40 based on the received positioning information, and manages the power state of each base station device 25. When the control device 35 detects that the terminal device 40 has approached within a predetermined distance of a base station device 25 that is powered off, it instructs that base station device 25 to turn on its power. Similarly, when the control device 35 determines the location of the terminal device 40 and detects that the terminal device 40 is not present within a predetermined distance of the base station device 25, it instructs that base station device 25 to turn off its power. This makes it possible to efficiently reduce the power consumption of the base station device 25 while suppressing the occurrence of coverage holes.

FIG. 20 is a block diagram showing the configuration of a base station device 25. In FIG. 20, only functional blocks related to this embodiment are shown. In the base station device 25 shown in FIG. 20, the same parts as those in the base station device 20 of the first embodiment shown in FIG. 3 are given the same reference numerals, and their description will be omitted. The base station device 25 comprises a wireless communication unit 251, a communication unit 202, a power supply control unit 203, a power supply unit 204, and a notification unit 252.

The wireless communication unit 251 performs wireless communication with the terminal device 40. Furthermore, the wireless communication unit 251 measures the relative position of the terminal device 40 with respect to the own device based on a communication signal wirelessly transmitted and received between the terminal device 40 and the own device. The relative position is represented by the distance and direction from the own device to the terminal device 40. The notification unit 252 notifies the control device 35 of positioning information indicating the relative position of the terminal device 40 measured by the wireless communication unit 251. The notification unit 252 may notify the control device 35 of positioning information obtained by converting the relative position of the terminal device 40 into position information in absolute coordinates using position information in the absolute coordinates of the own device.

Even when the power supply unit 204 is in a power-off state, it supplies power to the communication unit 202, the power supply control unit 203, and the notification unit 252, as well as to the wireless communication unit 251, enabling the transmission and reception of communication signals for determining the position of the terminal device 40.

21 is a functional block diagram showing the configuration of the control device 35. In FIG. 21, only functional blocks related to this embodiment are extracted and shown. In the control device 35 shown in FIG. 21, the same parts as those of the control device 31 of the second embodiment shown in FIG. 13 are given the same reference numerals, and their description will be omitted. The control device 35 includes a communication unit 301, a storage unit 311, a position acquisition unit 351, a control unit 352, and an update unit 314. The position acquisition unit 351 receives positioning information indicating the position of the terminal device 40 from the base station device 25. The control unit 352 instructs the base station device 25 to be powered on when the distance between the base station device 25 in a power-off state and the terminal device 40 is within a predetermined range.

The antenna provided in the wireless communication unit 251 of the base station device 25 does not need to be isotropic and may be a directional antenna. In this case, the orientation of the antenna of the base station device 25 to which the terminal device 40 can connect is limited to a certain direction. Therefore, the control unit 352 of the control device 35 may instruct the base station device 25 to turn on the power only when the terminal device 40 is within a specified distance and in a specified orientation from the base station device 25 in a power-off state.

FIG. 22 is a flow diagram showing the operation of the base station device 25. When the terminal device 40 is connected (step S81), the wireless communication unit 251 of the base station device 25 periodically performs terminal positioning using a communication signal. The notification unit 252 notifies the control device 35 of positioning information indicating the position of the terminal device 40 obtained by the terminal positioning (step S82). The notification unit 252 may set the terminal identification information of the terminal device 40 and information on the positioning time in the positioning information.

After waiting for a predetermined time (step S83), the wireless communication unit 251 of the base station device 25 detects whether the terminal device 40 connected in step S81 is still connected to the base station device 25 (step S84). If the wireless communication unit 251 detects that the terminal device 40 is still connected (step S84: YES), the process returns to step S82 and performs terminal positioning for the next period. On the other hand, if the wireless communication unit 251 detects that the terminal device 40 has been disconnected (step S84: NO), the process of FIG. 22 ends.

In the flow diagram shown in FIG. 22, the base station device 25 measures the terminal position at regular intervals, but the positioning period may be changed by detecting the moving speed of the terminal device 40, or the movement of the terminal device 40 itself may be detected in response to a change in the wireless propagation environment to perform terminal positioning. In addition, the base station device 25 may detect the position of the terminal device 40 in response to a request from the terminal device 40.

FIG. 23 is a flow diagram showing the operation of the control device 35. The position acquisition unit 351 of the control device 35 receives the positioning information notified from the base station device 25 via the communication unit 301 (step S91). The position acquisition unit 351 writes the received positioning information of each terminal device 40 into the storage unit 311.

The control unit 352 performs a proximity determination to determine whether the terminal device 40 is in the vicinity of any of the base station devices 25 that are powered off, based on the location information of the terminal device 40 indicated by the positioning information, the locations of each base station device 25 indicated by the equipment information, and the power information (step S92).

If the control unit 352 of the control device 35 determines that the terminal device 40 is in the vicinity of one of the base station devices 25 that is powered off (step S92: YES), it instructs the nearby base station device 25 to turn on the power (step S93). The power control unit 203 of the base station device 25 that was instructed to turn on the power turns the power unit 204 on. The update unit 314 of the control device 35 updates the power information stored in the memory unit 311 to indicate that the base station device 25 that instructed to turn on the power is powered on.

The vicinity in the above case may be within the coverage area B of the base station device 25, or may be within an area for power-on determination that is the coverage area B of the base station device 25 minus a margin, as shown in FIG. 24 described below. The margin is determined taking into consideration the time it takes for the terminal device 40 to approach the base station device 25 and the time it takes to turn on the power of the base station device 25. In addition, the facility information indicating the location information of each base station device 25 and the parameter information defining the vicinity may be set manually individually, or may be set automatically based on the location information of the base station device 25 that is measured or set by any method.

Furthermore, the determination of whether the terminal device 40 is close to the base station device 25 may be made based on information obtained by multiple terminal positioning operations, as shown in FIG. 25 described later. For example, the control unit 352 may extract the moving direction and moving speed of the terminal device 40 by multiple terminal positioning operations, and based on this, may turn on the power of the base station device 25 if there is a high possibility that the terminal device 40 will enter the area of a powered-off base station device 25.

If the control unit 352 determines that the terminal device 40 is not in the vicinity of a base station device 25 whose power is off (step S92: NO), or after the processing of step S93, the control unit 352 performs the processing of step S94. That is, the control unit 352 selects all base station devices 25 to which the terminal device 40 is not in the vicinity. The selected base station devices 25 are described as selected base station devices 25. The control unit 352 identifies adjacent base station devices 25 for each selected base station device 25 based on the equipment information stored in the storage unit 302. The control unit 352 selects, among the selected base station devices 25, the selected base station device 25 to which the terminal device 40 is not in the vicinity of any of the adjacent base station devices 25 as the base station device 25 to be powered off. The control unit 352 instructs the selected base station device 25 to be powered off to power off (step S94). The power control unit 203 of the base station device 25 to which the power off instruction is given sets the power unit 204 to the power off state. The update unit 314 of the control device 35 updates the power information stored in the memory unit 311 to indicate that the power of the base station device 25 that has been instructed to turn off the power is OFF.

As described above, after the control device 35 performs the proximity determination of the terminal device 40, for each base station device 25, it turns off the power of the base station device 25 for which there is no terminal device 40 in the vicinity of the base station device 25 and for which there is no terminal device 40 in the vicinity of the adjacent base station device 25. This makes it possible to reduce the power consumption of the base station device 25 by turning off the power of the base station device 25 to which there is no possibility of a terminal device 40 being connected.

24 is a diagram showing an example of a power-on determination area. In FIG. 24, the power-on determination area is an area B1, which is an area B2 in a predetermined direction centered on the base station device 25, plus an outer margin G, of the coverage area B of the base station device 25. The control unit 352 of the control device 35 may determine the margin G based on the time it takes for the terminal device 40 to approach the base station device 25. The time it takes for the terminal device 40 to approach the base station device 25 is calculated based on the speed and direction of the terminal device 40 calculated as described in FIG. 25. The control unit 352 of the control device 35 may determine the margin G based on the time it takes to turn on the power of the base station device 25, or it may be set in advance in the control unit 352 or the storage unit 311. If the terminal device 40 is present within the area B2 of the base station device 25, it is determined that the terminal device 40 is close to (near) the base station device 25.

FIG. 25 is a diagram showing an example of the operation of the control device 35 turning on the power of the base station device 25. First, the base station device 25-n (n is an integer between 1 and N) locates the position (t1) of the terminal device 40 at time t1. The base station device 25 also locates the position (t2) of the terminal device 40 at time t2. At this time, the control unit 352 of the control device 35 can detect that the terminal device 40 is moving in the direction of the arrow W. The control unit 352 of the control device 35 can also calculate the speed and direction of movement of the terminal device 40. Assuming that the terminal device 40 continues to move at the same speed and in the same direction, the control unit 352 of the control device 35 can estimate the position of the terminal device 40 after a predetermined time.

In the example shown in FIG. 25, if the terminal device 40 continues to move, there is a high possibility that it will enter the power-on determination area B2 of the base station device 25-m (m is an integer between 1 and N) that is powered off. Therefore, the control unit 352 turns on the power of the base station device 25-m. If the terminal device 40 enters the power-on determination area B2 of the base station device 25-m within a predetermined time or approaches within a predetermined distance, the control unit 352 may determine that the terminal device 40 is close to (near) the base station device 25-m. Note that the coverage area B of the base station device 25-m may be used as the power-on determination area B1.

[others]
The following items are common to the first to third embodiments. In the above description, the state in which the power consumption of the base station devices 20, 21, and 25 is reduced has been described as power OFF for the sake of simplicity, but this state also includes a state called a sleep state in which the power of the device is not completely turned off, but only the minimum functions necessary for remote activation of the device are turned on. In addition, the power OFF state includes all states in which the power consumption of the base station devices 20, 21, and 25 is controlled to be lower than that of the normal operation state of the base station devices 20, 21, and 25, such as reducing the frequency of transmission of notification signals such as beacon signals transmitted by the base station devices 20, 21, and 25 or completely stopping the transmission. Similarly, the state in which the base station devices 20, 21, and 25 operate with normal power consumption is referred to as a power ON state.

In the above embodiment, the operation of the centralized control type base station devices 20, 21, 25 controlled by the control devices 30, 31, 35, such as 3GPP (registered trademark) 5G, is explained as an example, but the present invention may be applied to base station devices of an autonomous distributed wireless communication system such as IEEE 802.11. In other words, the functions of the control devices 30, 31, 35 may be included in any of the base station devices 20, 21, 25, or may be distributed among them.

Furthermore, the timing of turning the power of the base station devices 20, 21, and 25 OFF or ON may be delayed. In other words, if it is assumed that the moving speed of the terminal device 40 does not exceed a certain level, it is assumed that it will not be connected to another base station device at a speed exceeding that level. Therefore, the timing of transmitting a signal instructing the base station device to turn on the power, or the timing of turning on the power of the base station device after receiving that signal, may be delayed. Similarly, it is also assumed that the terminal device 40 will leave the coverage area of a specific base station device 20, 21, and 25 and then return to that coverage area again. Therefore, the timing of transmitting a signal instructing the base station device to turn off the power, or the timing of turning off the power of the base station devices 20, 21, and 25 after receiving that signal may be delayed.

Furthermore, it is assumed that the terminal device 40 is connected to the base station devices 20, 21, 25 adjacent to each of the base station devices 20, 21, 25 at the edge of the area. For this reason, the control of turning the power OFF and ON may be performed across multiple base station devices, such as each base station device 20, 21, 25 and its adjacent base station devices 20, 21, 25.

Furthermore, each embodiment can be implemented in combination. For example, it is possible to turn on the power of the base station device by terminal positioning using a communication signal, and turn off the power depending on the connection status of the terminal device.

This embodiment can also be applied to a heterogeneous network. That is, this embodiment can be applied even under conditions where multiple base station devices are deployed with overlapping areas. In this case, there may be only one base station device that is powered on when a terminal device is present in the coverage area, or multiple base station devices may be powered on simultaneously to improve communication stability. The same applies to powering off.

According to the above-described embodiment, it is possible to reduce the power consumption of the base station device without creating a coverage hole.

The control devices 30, 31, and 35 may be realized by multiple computer devices connected to a network. In this case, it is possible to arbitrarily determine which of the multiple computer devices each functional unit of the control devices 30, 31, and 35 is realized by. In addition, the same functional unit may be realized by multiple computer devices.

The following describes an example of the hardware configuration of the control devices 30, 31, and 35. FIG. 26 is a device configuration diagram showing an example of the hardware configuration of the control devices 30, 31, and 35. The control devices 30, 31, and 35 each include a processor 71, a storage unit 72, a communication interface 73, and a user interface 74.

Processor 71 is a central processing unit that performs calculations and control. Processor 71 is, for example, a CPU. Processor 71 reads and executes programs from memory unit 72. Memory unit 72 further has a work area when processor 71 executes various programs. Communication interface 73 connects to other devices so that they can communicate with each other. User interface 74 is input devices such as a keyboard, pointing device (mouse, tablet, etc.), buttons, and touch panel, and display device such as a display. Human operations are input via user interface 74.

The functions of the notification receiving unit 303, control unit 304, and update unit 305 of the control device 30, the position acquisition unit 312, control unit 313, and update unit 314 of the control device 31, and the position acquisition unit 351, control unit 352, and update unit 314 of the control device 35 are realized by the processor 71 reading and executing programs from the memory unit 72. Note that all or part of these functions may be realized using hardware such as an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array). Also, the memory units 302 and 311 are realized by the memory unit 72.

According to the above-described embodiment, the wireless communication system has a plurality of base station devices and a control device. The control device includes an acquisition unit and a control unit. The acquisition unit corresponds to, for example, the notification receiving unit 303, the location acquisition unit 312, and the location acquisition unit 351 of the embodiment. The acquisition unit acquires terminal location information. The terminal location information indicates information related to the location where the terminal device is located. The control unit selects, from among the plurality of base station devices, a base station device that is to be subject to power control to change power consumption, based on the location of the terminal device indicated by the terminal location information and the respective locations of the plurality of base station devices, and instructs the selected base station device to perform power control. The base station device includes a wireless communication unit, a power supply unit, and a power supply control unit. The wireless communication unit wirelessly communicates with terminal devices present within the wireless communication area of the base station device. The power supply unit supplies power to at least the wireless communication unit. The power supply control unit controls to change the power supplied from the power supply unit based on an instruction from the control device.

The base station device may further include a notification unit that notifies the connection status of the terminal device in the wireless communication unit of the base station device. The acquisition unit of the control device acquires the notification from the notification unit of the base station device as terminal location information indicating whether or not the terminal device is located within the wireless communication area of the base station device.

The terminal location information may be obtained by analyzing an image including the wireless communication area of the base station device. The terminal location information may also be obtained by a positioning system that determines the position of the terminal device. The terminal location information may also be obtained based on a signal wirelessly transmitted and received between the wireless communication unit of the base station device and the terminal device.

Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configuration is not limited to these embodiments, and includes designs that do not deviate from the gist of the present invention.

10, 11, 12, 13, 15 Wireless communication system 20, 21, 25 Base station device 26 Beam 30, 31, 35 Control device 40 Terminal device 41 Position information acquisition unit 45 Vehicle 50 Imaging device 51 Positioning system 61, 65 Wireless station device 71 Processor 72 Memory unit 73 Communication interface 74 User interface 201, 251 Wireless communication unit 202 Communication unit 203 Power supply control unit 204 Power supply unit 205, 211, 252 Notification unit 301 Communication unit 302, 311 Memory unit 303 Notification receiving unit 304, 313, 352 Control unit 305, 314 Update unit 312, 351 Position acquisition unit 901, 903, 905 Base station device 902, 904, 907 Terminal device 906 Control device

Claims (8)

A wireless communication system having a plurality of base station devices and a control device,
The control device includes:
an acquisition unit that acquires terminal location information indicating information related to a location where a terminal device is located;
a control unit that selects, from among the plurality of base station devices, a base station device that is to be subject to power control for changing power consumption, based on a position of the terminal device indicated by the terminal position information and each of the plurality of base station devices, and instructs the selected base station device to perform the power control;
Equipped with
The base station device,
a wireless communication unit for wirelessly communicating with a terminal device present within a wireless communication area of the device;
a power supply unit for supplying power to at least the wireless communication unit;
a power supply control unit that controls the power supplied from the power supply unit to be changed based on the instruction from the control device;
Equipped with
Wireless communication system. The base station device,
A notification unit that notifies a connection status of a terminal device in the wireless communication unit of the device itself,
The acquisition unit acquires the notification from the base station device as the terminal location information indicating whether or not the terminal device is located within a wireless communication area of the base station device.
2. The wireless communication system according to claim 1. The terminal location information is obtained by analyzing an image including the wireless communication area.
2. The wireless communication system according to claim 1. The terminal location information is obtained by a positioning system that measures the position of the terminal device.
2. The wireless communication system according to claim 1. The terminal location information is obtained based on a signal wirelessly transmitted and received between the wireless communication unit of the base station device and the terminal device.
2. The wireless communication system according to claim 1. an acquisition unit that acquires terminal location information indicating information related to a location where a terminal device is located;
a control unit that selects a base station device to be subject to power control for changing power consumption from among a plurality of base station devices that wirelessly communicate with a terminal device present within a wireless communication area of the base station device, based on a position of the terminal device indicated by the terminal position information and the positions of each of the plurality of base station devices, and instructs the selected base station device to perform the power control;
A control device comprising: An acquisition step of acquiring terminal location information indicating information related to a location where a terminal device is present;
a control step of selecting a base station device to be subject to power control for changing power consumption from among a plurality of base station devices that wirelessly communicate with a terminal device present within a wireless communication area of the base station device itself, based on a position of the terminal device indicated by the terminal position information and the positions of each of the plurality of base station devices, and instructing the selected base station device to perform the power control;
A power supply control method comprising: On the computer,
An acquisition step of acquiring terminal location information indicating information related to a location where a terminal device is present;
a control step of selecting a base station device to be subject to power control for changing power consumption from among a plurality of base station devices that wirelessly communicate with a terminal device present within a wireless communication area of the base station device itself, based on a position of the terminal device indicated by the terminal position information and the positions of each of the plurality of base station devices, and instructing the selected base station device to perform the power control;
A program for executing.

Images