Wireless communication system, control device, and control method

Abstract

This wireless communication system comprises one or more mobile wireless station devices that communicate with one or more terminal devices, and comprises: a region calculation unit that calculates a placement region encompassing the position of a mobile wireless station device such that the communication quality of a terminal device satisfies a required quality; a selection unit that selects, on the basis of movement prediction for each of the mobile wireless station devices, a mobile wireless station device that has the greatest dwell time in the placement region; and a control unit that activates the wireless communication function of the mobile wireless station device selected by the selection unit.

Description

[Technical Field]

[0001] The present invention relates to a technique for performing ON / OFF control on a mobile radio station device such as a mobile relay station device. [Background technology]

[0002] Wireless communication technologies such as 5G and wireless LAN are becoming widespread. In recent years, as disclosed in Non-Patent Document 1, a technology has been proposed in which a relay station device is mounted on a mobile object (such as a forklift) that moves within a factory or the like, and the relay function is turned on and off as needed to improve area quality.

[0003] It is expected that this technology will provide a natural communication environment in which users are not aware of the wireless network. A relay station device mounted on a mobile object is called a mobile relay station device. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Institute of Electronics, Information and Communication Engineers 2022 General Conference B-5-27 Summary of the Invention [Problem to be solved by the invention]

[0005] Based on the technology disclosed in Non-Patent Document 1, in order to perform appropriate communication by controlling the ON / OFF of the mobile relay station devices, it is necessary to use the mobile relay station device closest to the optimum position in the ON state.

[0006] However, in the conventional technology, depending on the movement state of the mobile relay station device, ON / OFF switching occurs frequently, which may cause momentary communication interruptions due to connection switching, or the overhead caused by messaging may constrict the bandwidth. These issues are not limited to mobile relay station devices, but can occur in any mobile radio station device.

[0007] The present invention has been made in view of the above points, and has an object to provide a technique for reducing the frequency of ON / OFF switching in a technique for controlling ON / OFF of a mobile radio station device. [Means for solving the problem]

[0008] According to the disclosed technology, there is provided a wireless communication system including one or more mobile wireless station devices that communicate with one or more terminal devices, an area calculation unit that calculates a deployment area that includes the location of a mobile radio station device where the communication quality of the terminal device satisfies a required quality; a selection unit that selects a mobile radio station device that has the longest stay time in the deployment area based on a movement prediction of each mobile radio station device; a control unit that activates a wireless communication function of the mobile radio station device selected by the selection unit; A wireless communication system is provided, comprising: [Effects of the Invention]

[0009] According to the disclosed technique, in a technique for performing ON / OFF control on a mobile radio station device, it is possible to reduce the frequency of ON / OFF switching. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating an example of the overall configuration of a wireless communication system. [Figure 2] FIG. 1 is a diagram illustrating an example of the overall configuration of a wireless communication system. [Figure 3] FIG. 10 is a diagram for explaining an outline of an operation. [Figure 4] FIG. 1 is a diagram illustrating an example of an apparatus configuration. [Figure 5] 10 is a flowchart illustrating an operation. [Figure 6] FIG. 2 illustrates an example of a hardware configuration of the apparatus. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention (the present embodiment) will be described with reference to the drawings. The embodiment described below is merely an example, and the embodiment to which the present invention is applied is not limited to the following embodiment.

[0012] In the following description of the embodiment, a mobile relay station device mounted on a moving body is used as the mobile radio station device to be moved, but this is just one example. The mobile relay station device mentioned below may be replaced with a mobile base station device, a mobile AP, or other mobile radio station device. Note that "mobile XYZ" refers to "XYZ" mounted on a moving body (e.g., AGV, forklift). However, "mobile XYZ" may also be a device that itself has a means of movement (e.g., propeller + motor, tire + motor).

[0013] Furthermore, both the mobile relay station device and the base station device may be devices in a cellular communication network (e.g., 3G, 4G / LTE, 5G, 6G), devices in a wireless LAN, or devices in a communication system other than these. Furthermore, communication between the mobile relay station device and the base station device may be performed via a wireless LAN, and the base station device may be connected to the cellular communication network.

[0014] (Example of overall system configuration) An example of the overall configuration of a wireless communication system according to the present embodiment is shown in Fig. 1. As shown in Fig. 1, the wireless communication system includes a plurality of terminal devices 20, mobile relay station devices 10, base station devices 30, and a control device 40. Although Fig. 1 shows one mobile relay station device 10 and one base station device 30, a plurality of each may be provided.

[0015] 1, the control device 40 is provided on an upper NW (network) 50. However, the control device 40 may be provided anywhere. For example, the control device 40 may be provided in any of the terminal device 20, the mobile relay station device 10, and the base station device 30.

[0016] The terminal device 20 is a device capable of wirelessly communicating with both the relay station device 10 and the base station device 30. The mobile relay station device 10 relays communication between the terminal device 20 and the base station device 30. The base station device 10 transmits signals received wirelessly from the terminal device 20 to the upper NW 50, and transmits signals received from the upper NW 50 wirelessly to the terminal device 20.

[0017] The upper NW 50 may be a core network of a mobile network (for example, 5G), the Internet, or a network other than these. The control device 40 performs operations such as information collection and control.

[0018] (Operation overview) In this embodiment, basically, as disclosed in Non-Patent Document 1, the movement of the mobile relay station device 10 is not controlled, but the relay function of the mobile relay station device 10 is controlled to be turned on / off so that the mobile relay station device 10 appropriately performs relaying between the base station device 30 and the terminal device 20.

[0019] As a result, even if, for example, an obstacle blocks the line of sight between the terminal device 20 and the base station device 30 or the distance between the terminal device 20 and the base station device 30 is long, by turning on the mobile relay station device 10 at an appropriate location, it is possible to properly communicate between the terminal device 20 and the base station device 30 via the mobile relay station device 10.

[0020] In order for the mobile relay station device 10 to perform appropriate relaying, it is necessary to use the mobile relay station device 10 closest to the optimal position in the ON state. As mentioned above, at this time, depending on the movement state of the mobile relay station device 10, ON / OFF switching may occur frequently, which may cause momentary communication interruptions due to connection switching or may constrict the bandwidth due to overhead caused by messaging.

[0021] In this embodiment, in order to solve the above problem, the control device 40 first calculates an optimal position candidate area (which may also be called a placement area) for the mobile relay station device 10 in which the communication quality of the terminal device 20 satisfies the required quality.

[0022] Then, the control device 40 turns on the relay function of the mobile relay station device 10 that has the longest stay time in the calculated optimum position candidate area based on the planned or predicted movement route of each mobile relay station device 10. Turning on the relay function of the mobile relay station device 10 can also be said to operate the wireless communication function of the mobile relay station device 10. This makes it possible to maintain the ON state for a longer period of time and reduce the frequency of switching ON / OFF. An example of control will be described below.

[0023] 2, it is assumed that there are a plurality of mobile relay station devices 10 and a plurality of terminal devices 20 in an area (target area) that is the target of control by a control device 40. There is also a control device 40 that performs ON / OFF control of the mobile relay station devices 10. There is also a fixed base station device 30.

[0024] Each mobile relay station device 10 moves according to the purpose of the mobile object on which the relay station device is mounted. For example, if the mobile object is an AGV (automated guided vehicle) that carries an object from one location A to another location B, the mobile relay station device 10 moves along a passage between location A and location B.

[0025] It is assumed that the control device 40 has calculated the shaded area in Fig. 3 as the optimum position candidate area. Here, the mobile relay station devices 10 that pass through the optimum position candidate area include mobile relay station devices 10-1, 10-2, and 10-3.

[0026] Based on the movement predictions of each mobile relay station device 10, the control device 40 determines that the stay time of mobile relay station device 10-1 is the longest among the stay times in the optimum position candidate area of ​​the three mobile relay station devices 10, and turns on the relay function of mobile relay station device 10-1. For example, the control device 40 turns on the relay function of mobile relay station device 10-1 when mobile relay station device 10-1 enters the optimum position candidate area (or just before or just after entering), and turns off the relay function of mobile relay station device 10-1 after mobile relay station device 10-1 leaves the optimum position candidate area.

[0027] Although the example in FIG. 3 shows one optimum position candidate area, there may be a plurality of optimum position candidate areas.

[0028] (Device configuration example) 4 shows an example of the configuration of devices constituting the wireless communication system according to the present embodiment (particularly, an example of the configuration of the control device 40). As shown in FIG. 4, the wireless communication system includes the control device 40, a base station device 30, a mobile relay station device 10, and a terminal device 20.

[0029] The control device 30 and the base station device 10 are connected by wire or wirelessly. The base station device 30 and the mobile relay station device 10 are connected wirelessly, and the mobile relay station device 10 and the terminal device 20 are also connected wirelessly. However, wireless communication between the mobile relay station device 10 and the terminal device 20 is performed only while the mobile relay station device 10 has its relay function turned on.

[0030] The control device 40 transmits an instruction message to the mobile relay station device 10 to turn on (or off) the mobile relay station device 10. The switching unit 11 of the mobile relay station device 10 receives the instruction message and turns on / off the relay function of the mobile relay station device 10 based on the instruction message.

[0031] As shown in FIG. 4, the control device 40 includes an information acquisition unit 41, a region calculation unit 42, a selection unit 43, and a control unit 44.

[0032] The information acquisition unit 41 acquires the position of each terminal device 20 in the target area, information on obstructions (position, shape, etc.), and information (movement schedule, movement history, etc.) necessary for predicting the position (or route) of each mobile relay station device 10. The information acquisition unit 41 may include an environment recognition unit (camera, sensor, etc.), and the environment recognition unit may acquire the position of each terminal device 20 and information on obstructions.

[0033] The area calculation unit 42 calculates an optimum location candidate area by performing terminal clustering, etc., as will be described later. The selection unit 43 selects the mobile relay station device 10 that will have the longest stay time in the optimum location candidate area. The control unit 44 performs ON / OFF control for the selected mobile relay station device 10.

[0034] 4 is an example. The information acquisition unit 41, the region calculation unit 42, the selection unit 43, and the control unit 44 may each be provided in any device within the wireless communication system. For example, the control device 40 may include the information acquisition unit 41, and the base station device 30 may include the region calculation unit 42, the selection unit 43, and the control unit 44. Any device including the region calculation unit 42 and the selection unit 43 may be called a "control device."

[0035] (Example of operation) Next, the operation of the control device 40 will be described in accordance with the procedure of the flowchart in FIG.

[0036] <s101> In S101, the information acquisition unit 41 acquires the position of each terminal device 20 in the target area, information on obstructions (position, shape, etc.), and information necessary for predicting the position (or route) of each mobile relay station device 10 (movement schedule, movement history, etc.).

[0037] <s102> In S102, the area calculation unit 42 calculates one or more optimum position candidate areas. The method for calculating the optimum position candidate area is not limited to a specific method, but for example, the following calculation method example 1 or calculation method example 2 can be used.

[0038] Note that the following calculation method examples 1 and 2 assume that the antenna of the mobile relay station device 10 is an omnidirectional antenna. If the antenna of the base station device 10 is a directional antenna (an antenna whose direction can be changed), for example, in the calculation of the predicted communication quality below, the predicted communication quality may be calculated when the antenna is pointed in the direction that provides the best predicted communication quality.

[0039] Calculation method example 1: The area calculation unit 42 first randomly changes the terminal clustering initial value for multiple terminal devices 20 in the target area and performs terminal clustering using the k-means method. Specifically, for example, the initial terminal clustering value is set to the number (M) of target mobile relay station devices 10, and multiple terminal devices 20 are divided into M clusters. This type of clustering is performed multiple times by randomly changing the terminal clustering initial value. Note that clustering may also be performed using hierarchical clustering.

[0040] The area calculation unit 42 moves (on a computer) the mobile relay station device 10 to a predetermined position within each cluster, and obtains position candidates where the predicted communication quality after the movement (predicted communication quality at the terminal device 20) is equal to or greater than a predetermined value. That is, it calculates position candidates for each mobile relay station device 10 where communication with the terminal device 20 satisfies the required quality. The quality to be evaluated may be the quality of communication between the mobile relay station device 10 and the terminal device 20, or the quality of communication between the base station device 30 and the terminal device 20.

[0041] The area including the above location candidates is defined as the optimum location candidate area. The shape and size of the area may be the same as the shape and size of the cluster, or may be a predetermined shape and size.

[0042] Here, the predetermined position within the cluster is, for example, the center of gravity of the cluster. Alternatively, if the base station device 30 cannot be seen from the center of gravity, the predetermined position may be the position closest to the center of gravity among the positions within the cluster from which the base station device 30 can be seen. Furthermore, in this embodiment, each mobile relay station device 10 may move along a position (route) from which the base station device 30 can be seen.

[0043] Furthermore, when a mobile relay station device 10 is moved (on a computer) to a predetermined position within a cluster, the mobile relay station device 10 may be any one of the mobile relay station devices 10, or may be a specific mobile relay station device 10 that can move within the cluster.

[0044] Furthermore, among the multiple clusters obtained as a result of clustering, clusters that the mobile relay station device 10 does not pass through at all may be excluded from the targets for calculating position candidates.

[0045] For example, for three mobile relay station devices 10, it is assumed that (P11, P12, P13) and (P21, P22, P23) are obtained as the positions (predetermined positions within the cluster) of the mobile relay station devices 10 based on two clustering operations with different initial values.

[0046] Here, if the evaluation based on predicted communication quality shows that only P11 of (P11, P12, P13) meets the required quality, and among (P21, P22, P23), P21 and P22 meet the required quality, then (P21, P22, P23) are selected as the clustering result, and the area of ​​P21 and the area of ​​P22 are set as optimal location candidate areas, respectively. However, this processing method is just one example.

[0047] The method for calculating the predicted communication quality is not limited to a specific method, but for example, the visibility area ratio, the predicted throughput integrated value, or the rate of terminals achieving the required quality can be used.

[0048] The visibility area ratio is the ratio of the area of ​​the target area where the terminal devices 20 are located and the mobile relay station devices 10 can be seen from the terminal devices 20 (i.e., there are no obstacles between the terminal devices 20 and the mobile relay station devices 10). For example, by dividing the target area into mesh areas, it is possible to find the area of ​​the area where the terminal devices 20 are located and the mobile relay station devices 10 can be seen from the terminal devices 20.

[0049] The integrated predicted throughput value is a value obtained by integrating (summing up) the predicted throughputs of the terminal device 20 for all terminal devices 20 within the cluster of the mobile relay station device 10. The throughput can be estimated from the received power of the signal from the mobile relay station device 10 at the terminal device 20.

[0050] The rate of terminals achieving the required quality is the rate of terminal devices 20 that achieve the required quality among all terminal devices 20 in the cluster of the mobile relay station device 10. The required quality is, for example, throughput. As described above, the throughput can be estimated from the received power, so by comparing the estimated throughput with the required quality, it is possible to determine for each terminal device 20 whether the required quality is achieved.

[0051] Note that, as in calculation method example 1, performing terminal clustering has the effect of reducing the amount of calculation. If clustering is not performed, the path loss and the like between each mobile relay station device and all terminal devices in the target area are calculated for all combinations of mobile relay station device placements to determine the reception quality at the terminal point, as will be explained in calculation method example 2, which can result in a large amount of calculation depending on the conditions. In contrast, by performing terminal clustering, the path loss between the terminal devices included in each cluster and the corresponding mobile relay station device 10 is calculated, making it possible to determine position candidates while reducing the amount of calculation.

[0052] Calculation method example 2: The area calculation unit 42 calculates the predicted communication quality for all possible location candidates of each mobile relay station device 10, obtains location candidates whose predicted communication quality is equal to or greater than a predetermined value, and sets the area including the location candidates as the optimal location candidate area. An example of the method for calculating the predicted communication quality is as described above.

[0053] <s103> In S103, the selection unit 43 performs movement prediction (prediction of when and where each mobile relay station device 10 will be located) for each optimal position candidate area, and selects, for each optimal position candidate area, the mobile relay station device 10 that will have the longest stay time in the optimal position candidate area.

[0054] For example, assuming there are mobile relay station device 10-1 and mobile relay station device 10-2, if the selection unit 43 detects that for a certain optimum position candidate area, mobile relay station device 10-1 will be present from 11:00 to 12:00 and mobile relay station device 10-2 will be present from 11:00 to 11:30, then the selection unit 43 selects mobile relay station device 10-1 as the ON control target for that optimum position candidate area.

[0055] Any method may be used for predicting the movement of each mobile relay station device 10. For example, a predicted value obtained by machine learning or the like may be used, or in the case of a factory or the like, movement prediction may be performed by acquiring a movement schedule from a control program of a moving body that carries the mobile relay station device 10.

[0056] <s104> In S104, based on the selection result in S103, the control unit 44 executes ON / OFF control for the mobile relay station device 10. Specifically, the control unit 44 instructs the mobile relay station device 10 to turn on or off the relay function by a predetermined message.

[0057] For example, if mobile relay station device 10-1 is scheduled to stay in the optimum position candidate area from 11:00 to 12:00, when control unit 44 detects that mobile relay station device 10-1 has entered the optimum position candidate area (or when it detects that 11:00 has arrived), it executes control to turn on the relay function of mobile relay station device 10-1.

[0058] (Example of hardware configuration) The terminal device 20, the mobile relay station device 10, the base station device 30, and the control device 40 can all be realized, for example, by causing a computer to execute a program. This computer may be a physical computer or a virtual machine on the cloud. Hereinafter, the "terminal device 20, the mobile relay station device 10, the base station device 30, and the control device 40" will be collectively referred to as "devices."

[0059] That is, the device can be realized by executing a program corresponding to the processing performed by the device using hardware resources such as a CPU and memory built into a computer. The program can be recorded on a computer-readable recording medium (such as a portable memory) and stored or distributed. The program can also be provided via a network such as the Internet or email.

[0060] Fig. 6 is a diagram showing an example of the hardware configuration of the computer. The computer in Fig. 6 includes a drive device 1000, an auxiliary storage device 1002, a memory device 1003, a CPU 1004, an interface device 1005, a display device 1006, an input device 1007, an output device 1008, and the like, all of which are interconnected via a bus BS.

[0061] A program for realizing processing on the computer is provided by a recording medium 1001 such as a CD-ROM or a memory card. When the recording medium 1001 storing the program is set in the drive device 1000, the program is installed from the recording medium 1001 to the auxiliary storage device 1002 via the drive device 1000. However, the program does not necessarily have to be installed from the recording medium 1001, but may be downloaded from another computer via a network. The auxiliary storage device 1002 stores the installed program as well as necessary files, data, etc.

[0062] When an instruction to start a program is received, the memory device 1003 reads and stores the program from the auxiliary storage device 1002. The CPU 1004 implements the functions related to the device in accordance with the program stored in the memory device 1003.

[0063] The interface device 1005 is used as an interface for connecting to a network or the like. The display device 1006 displays a GUI (Graphical User Interface) or the like according to a program. The input device 1007 is composed of a keyboard, mouse, buttons, a touch panel, or the like, and is used to input various operation instructions. The output device 1008 outputs the results of calculations. Note that any or all of the display device 1006, input device 1007, and output device 1008 may be omitted.

[0064] (Effects of the embodiment) As described above, the technology according to the present embodiment can reduce the frequency of ON / OFF control of the mobile relay station device 10, thereby making it possible to avoid momentary communication interruptions due to connection switching and bandwidth congestion due to messaging.

[0065] (Addendum) This specification discloses at least the following wireless communication systems, control devices, and control methods. (Additional note 1) A wireless communication system including one or more mobile wireless station devices that communicate with one or more terminal devices, Memory and at least one processor coupled to said memory; Including, The processor: calculating a deployment area that includes the location of a mobile radio station device where the communication quality of the terminal device satisfies a required quality; selecting a mobile radio station device having the longest stay time in the deployment area based on the movement prediction of each mobile radio station device; Activating the wireless communication function of the selected mobile radio station device Wireless communication system. (Additional note 2) The processor calculates the placement area by performing clustering on the terminal device. Item 1. A wireless communication system according to claim 1. (Additional note 3) Each mobile radio station device is a relay station device that relays communications between a base station device and a terminal device, and is a relay station device mounted on a mobile object. 3. The wireless communication system according to claim 1 or 2. (Additional note 4) A control device in a wireless communication system including one or more mobile radio station devices that communicate with one or more terminal devices, the control device comprising: Memory and at least one processor coupled to said memory; Including, The processor: calculating a deployment area that includes the location of a mobile radio station device where the communication quality of the terminal device satisfies a required quality; selecting a mobile radio station device having the longest stay time in the deployment area based on the movement prediction of each mobile radio station device; Activating the wireless communication function of the mobile radio station device selected by the selection unit Control device. (Additional note 5) A computer-implemented control method in a wireless communication system including one or more mobile wireless station devices that communicate with one or more terminal devices, comprising: calculating a deployment area including the location of a mobile radio station device where the communication quality of the terminal device satisfies a required quality; selecting a mobile radio station device having the longest stay time in the deployment area based on the movement prediction of each mobile radio station device; Activating the wireless communication function of the selected mobile radio station device Control method.

[0066] Although the present embodiment has been described above, the present invention is not limited to such a specific embodiment, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims. [Explanation of symbols]

[0067] 10 Mobile relay station equipment 20 Terminal equipment 30 Base station equipment 40 Control device 41 Information Acquisition Department 42 Area calculation section 43 Selection section 44 Control Unit Top 50 Networks 1000 Drive Device 1001 Recording media 1002 Auxiliary storage 1003 Memory device 1004 CPU 1005 Interface device 1006 Display device 1007 Input Device 1008 Output Device

Claims

1. A wireless communication system including one or more mobile wireless station devices that communicate with one or more terminal devices, an area calculation unit that calculates a deployment area that includes the location of a mobile radio station device where the communication quality of the terminal device satisfies a required quality; a selection unit that selects a mobile radio station device that has the longest stay time in the deployment area based on a movement prediction of each mobile radio station device; a control unit that activates a wireless communication function of the mobile radio station device selected by the selection unit; A wireless communication system comprising:

2. The area calculation unit calculates the placement area by performing clustering on the terminal device.

10. The wireless communication system of claim 1.

3. Each mobile radio station device is a relay station device that relays communications between a base station device and a terminal device, and is a relay station device mounted on a mobile object.

10. The wireless communication system of claim 1.

4. A control device in a wireless communication system including one or more mobile radio station devices that communicate with one or more terminal devices, the control device comprising: an area calculation unit that calculates a deployment area that includes the location of a mobile radio station device where the communication quality of the terminal device satisfies a required quality; a selection unit that selects a mobile radio station device that has the longest stay time in the deployment area based on a movement prediction of each mobile radio station device; a control unit that activates a wireless communication function of the mobile radio station device selected by the selection unit; A control device comprising:

5. A computer-implemented control method in a wireless communication system including one or more mobile wireless station devices that communicate with one or more terminal devices, comprising: calculating a deployment area including the location of a mobile radio station device where the communication quality of the terminal device satisfies a required quality; selecting a mobile radio station device having the longest stay time in the deployment area based on the movement prediction of each mobile radio station device; Activating the wireless communication function of the selected mobile radio station device Control method.

Images