COMMUNICATION SYSTEM, CONTROL SERVER DEVICE, CONTROL METHOD, AND PROGRAM

Abstract

This communication system comprises a control server device and a mobile base station device, wherein the control server device selects, as a movement destination position of the mobile base station device, a position where a movement distance from a current position of the mobile base station device is the shortest, among positions where a base station position evaluation index is equal to or greater than a threshold, or a position where the base station position evaluation index is the maximum, among positions where the movement distance from the current position of the mobile base station device is equal to or less than the threshold, and the control server device performs control to move the mobile base station device to the movement destination position.

Description

[Technical field]

[0001] The present invention relates to a method for controlling a base station in a wireless communication system. [Background technology]

[0002] The introduction of 5G is underway, which will realize large-capacity systems, high data transmission speeds, low latency, simultaneous connection of many terminals, etc. In addition to the frequency bands currently used in mobile communications, 5G will use high frequency bands such as millimeter wave bands (Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] 5G Outdoor Experiments of Ultra-High Speed, Long Distance Transmission Using Millimeter Waves, Kishiyama, Okumura, et al., DoCoMo Technical Journal (Vol. 26-1, P25-32) Summary of the Invention [Problem to be solved by the invention]

[0004] There are use cases in which wireless communication services are provided by wireless systems (wireless LAN, local 5G, etc.) that are expected to use high-frequency bands in logistics centers, exhibition halls (event venues), etc. However, communication quality is unstable in logistics centers and exhibition halls where there are many obstructions and the obstructions move. In addition, radio waves in high-frequency bands such as 5G tend to travel in a very straight line, and loss due to obstruction is significant.

[0005] Therefore, a technology has been proposed that controls a mobile base station in real time, taking into consideration the positions of terminals and obstructions, etc. However, in the technology that controls a mobile base station in real time, the location of the mobile base station may change significantly for each control depending on the control method and environment, resulting in a period in which the base station is not optimally located, and during that period there may be a deterioration in quality.

[0006] The present invention has been made in consideration of the above points, and aims to provide a technology for controlling a mobile base station in real time, which makes it possible to reduce the movement time of the mobile base station. [Means for solving the problem]

[0007] According to the disclosed technology, there is provided a communication system including a control server device and a mobile base station device, the control server device selects a position where a moving distance from the current position of the mobile base station device is the shortest among positions where a base station position evaluation index is equal to or greater than a threshold value as a moving destination position of the mobile base station device; The control server device controls the movement of the mobile base station device to the destination position. A communication system is provided. Effect of the Invention

[0008] According to the disclosed technology, it is possible to reduce the movement time of a mobile base station, and to suppress the occurrence of periods in which communication quality deteriorates. [Brief description of the drawings]

[0009] [Figure 1] A top view of an area with shelves, objects, and other obstructions [Diagram 2] 1 is a diagram illustrating an example of the overall configuration of a wireless communication system according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a diagram illustrating the configuration of a control server. [Figure 4] FIG. 2 is a diagram illustrating the configuration of a mobile base station. [Diagram 5] FIG. 13 is a diagram showing an example in which a mobile base station is mounted on a mobile structure. [Figure 6] FIG. 1 is a diagram for explaining an overview of a first embodiment. [Figure 7] 4 is a flowchart showing an operation example of the first embodiment. [Figure 8] FIG. 2 is a diagram for explaining area elements in a target area. [Figure 9] 13 is a flowchart showing an operation example of the second embodiment. [Figure 10] 13 is a flowchart showing an operation example of the second embodiment. [Figure 11] FIG. 2 illustrates an example of a hardware configuration of the apparatus. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] 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.

[0011] For example, in the following description of the embodiment, when a two-dimensional position is used as an example of the position of a terminal or a base station, a three-dimensional position may be used as the position of the terminal or the base station. Also, since the base station, mobile base station, terminal, and control server in this specification are all "devices," they may be called base station devices, mobile base station devices, terminal devices, and control server devices.

[0012] (Outline of the embodiment) As mentioned above, in real-time mobile base station control that takes into account the positions of terminals and obstructions, etc., the location of a mobile base station may change significantly for each control depending on the control method and environment, resulting in periods of base station placement that are not of optimal quality, and during those periods there may be a deterioration in quality.

[0013] An example of a situation in which the above-mentioned event occurs will be described with reference to Fig. 1. Fig. 1 shows a situation in which base station 1, base station 2, and multiple terminals exist in a building. Also, within the building, there are obstacles such as building pillars, shelves, and articles.

[0014] In the control example in Fig. 1(a), the base station 1 moves from the position indicated by A to the position indicated by B, and then moves to the position indicated by C. On the other hand, in the control example shown in Fig. 1(b), the base station 1 moves to the position indicated by D near A, and then moves to the position indicated by C.

[0015] As in the case of Fig. 1(a), when the travel distance of base station 1 increases, the time required for travel increases, resulting in periods of time when the quality is not optimal, and during those periods the quality may deteriorate. In this embodiment, as shown in Fig. 1(b), it is possible to reduce the travel time by shortening the travel distance of base station 1.

[0016] In this embodiment, the control server 100 described later selects a destination in consideration of the moving distance of the mobile base station while maintaining the required communication quality in order to reduce the moving time of the mobile base station. The details will be described in the following examples 1 to 3, but the outline is as follows.

[0017] In the first embodiment, a threshold is set for the base station position evaluation index to control the moving range of the mobile base station within a range that satisfies the required communication quality. In the second embodiment, a movable range of the mobile base station is set, and the location with the highest base station position evaluation index within that range is selected as the moving destination of the mobile base station.

[0018] In the third embodiment, control is performed to place a mobile base station at the center of gravity of a terminal cluster, and in this case, outliers (outlier terminals) are excluded to find the center of gravity.

[0019] The above technology makes it possible to control communication quality and the movement range of a mobile base station. More specifically, it is possible to reduce the movement time of a mobile base station, making it possible to suppress the occurrence of periods in which communication quality declines. Also, if there is a bias in the distribution of terminal positions or speeds (acceleration), it is possible to suppress the movement range of a mobile base station by eliminating that bias.

[0020] (Overall composition) An example of the overall configuration of a wireless communication system according to this embodiment is shown in Fig. 2. As shown in Fig. 2, the wireless communication system according to this embodiment has a control server 100, a movable base station 200, a terminal 300, a spatial information DB (database) 400, and a spatial recognition server 500. Although only one movable base station 200 and one terminal 300 are shown, there may be multiple of each.

[0021] The control server 100 may be located on a cloud, or may be located on a network (wireless LAN, wired LAN, etc.) together with the mobile base station 200. The spatial information DB 400 and the spatial recognition server 500 may also be located on a cloud, or may be located on the above network.

[0022] The spatial information DB 400 stores information such as the terminal's position information, the position and material of an obstruction, etc., calculated by the spatial recognition server 500. The spatial recognition server 500 calculates the terminal's position information, the obstruction's position information, etc., based on camera image information, LiDAR information, etc., and stores the calculated information in the spatial information DB 400.

[0023] More specifically, the spatial information DB 400 stores, for each obstruction, for example, the shape (including thickness), position within the area, material, attenuation per unit thickness, etc. Note that the attenuation per unit thickness may be calculated from the material in the control server 100. Furthermore, the spatial information DB 400 stores, for each terminal, for example, the current position, the base station to which the terminal is connected, etc.

[0024] The control server 100 acquires information from the spatial information DB 400, and controls the mobile base station 200 based on the acquired information.

[0025] The movable base station 200 is placed in a position where it can communicate with the control server 100, and accommodates a terminal 300. The terminal 300 connects to the movable base station 200, and connects to a local network or the Internet via the movable base station 200.

[0026] (Configuration of control server 100) Fig. 3 shows an example of the configuration of the control server 100. As shown in Fig. 3, the control server 100 includes an information communication I / F unit 110, a shielding object information acquisition unit 120, a terminal information acquisition unit 130, a base station control calculation unit 140, a base station control unit 150, and a control communication I / F unit 160.

[0027] The information communication I / F unit 110 is connected to the spatial information DB 400, and transmits and receives information on obstructions and terminal information.

[0028] The obstructing object information acquisition unit 120 acquires information such as the shape, position, and material (quality) of the obstructing object from the spatial information DB 400. The terminal information acquisition unit 130 acquires the position information of the terminal 300 from the spatial information DB 400.

[0029] The base station control calculation unit 140 acquires information on the obstruction and the terminal 300 from the obstruction information acquisition unit 120 and the terminal information acquisition unit 130 respectively, and calculates the installation position of the mobile base station 200 and the connection destination of the terminal 300.

[0030] The base station control unit 150 controls the mobile base station 200 based on the result calculated by the base station control calculation unit 140. The control communication I / F unit 160 connects to the mobile base station 200 and transmits and receives control communication. Regarding the control of the connection destination of the terminal 300, the base station control unit 150 may instruct the mobile base station 200 to control the connection destination of the terminal 300, or may instruct the terminal 300 on the connection destination.

[0031] (Example of configuration of mobile base station 200) Fig. 4 shows a configuration example of the mobile base station 200. As shown in Fig. 4, the mobile base station 200 has a control communication I / F unit 210, a mobile control unit 220, a terminal connection control unit 230, and a radio transmission / reception unit 240. Note that Fig. 4 particularly shows functions related to position control and terminal control in the mobile base station 200.

[0032] The control communication I / F unit 210 is connected to the control server 100 and transmits and receives control information. The mobility control unit 220 receives control information from the control server 100 and controls the position of the mobile base station 200.

[0033] The terminal connection control unit 230 receives control information from the control server 100 and controls the connection of the terminal 300. The terminal connection control unit 230 also changes the connection destination of the target terminal 300. The wireless transmission / reception unit 240 connects to the terminal 300 and transmits and receives a connection destination control signal for the terminal 300.

[0034] In addition, if the movable base station 200 is mounted on, for example, a drone, the movable control unit 220 receives information from the control server 100 regarding the location where the movable base station 200 should be placed, and instructs the drone to move to that location.

[0035] 5, the movable base station 200 may be configured to have a movable structure supporting the available base station 200. The movable structure moves the movable base station 200 in the direction of arrow 201, for example, based on position information transmitted from the control server 100. The movable structure may also rotate the movable base station 200 around the x-axis (see reference symbol 203), the y-axis (see reference symbol 204), and the z-axis (see reference symbol 205), for example, based on control information transmitted from the control server 100.

[0036] Also, the movable structure on which the mobile base station 200 is mounted may be moved manually, with detailed position control being performed by the control server 100.

[0037] Hereinafter, embodiments 1 to 3 will be described as examples of control operations by the control server 100. For convenience of explanation, in embodiments 1 and 2, the control operations for one mobile base station 200 will be described.

[0038] Example 1 In the first embodiment, the control server 100 sets a threshold value for the base station position evaluation index, thereby controlling the movement range of the mobile base station 200 within a range in which the base station position evaluation index satisfies the threshold value.

[0039] An overview of the first embodiment will be described with reference to Fig. 6. In Fig. 6(a) and (b), a shaded circle indicates the current position of the mobile base station 200, a solid circle indicates a candidate position for the mobile base station to move to, and a dotted circle indicates a possible position for the mobile base station.

[0040] For comparison with Fig. 6(b), Fig. 6(a) shows the current position of the mobile base station and the position of the destination when no threshold is set for the base station position evaluation index. When no threshold is set for the base station position evaluation index, the destination position that is assumed to have the best base station position evaluation index and the best communication quality is selected. Therefore, the moving distance of the mobile base station 200 becomes longer than in the case of Fig. 6(b).

[0041] Fig. 6(b) shows the current position of the mobile base station and the candidate destination positions when a threshold is set for the base station position evaluation index. As shown in Fig. 6(b), when a threshold is set for the base station position evaluation index, multiple candidate destination positions that satisfy the required communication quality are selected.

[0042] By increasing the number of possible candidate locations, it is possible to select candidate destination locations based on various criteria. For example, it is possible to select a destination with the shortest travel distance. It is also possible to select a location that is easy to travel to (such as one without obstacles on the travel path) as the destination.

[0043] An example of the operation of the control server 100 in the first embodiment will be described below in accordance with the procedure of the flowchart in Fig. 7. In the following control example, there is an area to be controlled, and this area is called the controlled area. As shown in Fig. 1, the controlled area includes the mobile base station 200, the terminal 300, and obstructions. Also, as shown in Fig. 8, the controlled area is divided into sections of a predetermined size, and each divided area is called an "area element" or "element." The same applies to the other embodiments.

[0044] (S101) In S101, a threshold value for a base station position evaluation index is set for the control server 100. The set threshold value is stored in a storage means such as a memory of the control server 100, and is referred to by the base station control calculation unit 140.

[0045] <Base station location evaluation index> The base station position evaluation index is an index used when calculating candidate positions for the movement destination of the mobile base station 200, and examples of the base station position evaluation index will be described below together with the method of obtaining the index.

[0046] <Base station location evaluation index example 1: Number of terminals within line of sight> The number of terminals within line of sight is the number of terminals that can be seen without being blocked by any obstruction from the mobile base station 200. The method for acquiring the number of terminals within line of sight is as follows.

[0047] First, the obstructing object information acquisition unit 120 acquires the position information of each obstructing object from the spatial information DB 400 , and the terminal information acquisition unit 130 acquires the position information of each terminal 300 .

[0048] Next, the base station control calculation unit 140 uses the position information of each obstacle and the position information of each terminal to determine whether each terminal is visible from the mobile base station 200, and calculates the number of terminals within the line of sight. The presence or absence of visibility can be determined, for example, by whether a straight line can be drawn from the antenna of the mobile base station 200 to the terminal 300 without colliding with an obstacle.

[0049] <Base station location evaluation index example 2: Number of area elements within line of sight> The number of area elements within line of sight is the number of area elements that can be seen from the mobile base station 200 without being obstructed by any obstacles.

[0050] The base station control calculation unit 140 uses the position information of each obstruction and the position information of each area element to determine whether each area element is within line of sight from the mobile base station 200, and calculates the number of area elements within line of sight.

[0051] <Base station location evaluation index example 3: communication quality of area element> The communication quality of an area element is the communication quality such as throughput in each area element.

[0052] The base station control calculation unit 140 obtains the propagation loss from the antenna of the mobile base station 200 to the area element for each area element in the area by ray tracing simulation or the like, calculates the estimated received power by transmission output-propagation loss, and estimates the communication quality from the estimated received power. The base station control calculation unit 140 uses, for example, the sum or average of the communication quality in all area elements as the base station position evaluation index.

[0053] <Base station location evaluation index example 4: Terminal communication quality> The communication quality of the terminal is the communication quality such as the throughput at each terminal. The base station control calculation unit 140 obtains the propagation loss from the antenna of the mobile base station 200 to the terminal for each terminal by ray tracing simulation or the like, calculates the estimated received power by transmission output-propagation loss, and estimates the communication quality from the estimated received power. For example, the base station control calculation unit 140 sets the average value of the communication quality at all terminals as the base station position evaluation index.

[0054] (S102) In S102, the base station control calculation unit 140 calculates a base station position evaluation index for each possible location of the mobile base station 200 (for example, for each possible area element), and calculates a possible location where the base station position evaluation index is equal to or greater than a threshold as a candidate location of the destination. In S102, multiple candidate locations of the destination are calculated.

[0055] For example, if the base station position evaluation index is the number of terminals within line of sight and the threshold is TH1, the base station control calculation unit 140 calculates possible locations where the "base station position evaluation index ≧TH1" as candidate locations for the destination.

[0056] For example, if the base station position evaluation index is the number of line-of-sight area elements and the threshold is TH2, the base station control calculation unit 140 calculates possible locations where the "base station position evaluation index ≧TH2" as candidate destination locations.

[0057] For example, if the base station position evaluation index is the communication quality of the area element and the threshold is TH3, the base station control calculation unit 140 calculates possible locations where the "base station position evaluation index ≧TH3" is satisfied as candidate locations for the destination.

[0058] For example, if the base station position evaluation index is the terminal communication quality and the threshold is TH4, the base station control calculation unit 140 calculates possible locations where the "base station position evaluation index ≧TH4" is satisfied as candidate locations for the destination.

[0059] (S103) In S103, the base station control calculation unit 140 selects the post-movement position where the distance between the pre-movement position and the post-movement position of the mobile base station 200 is the shortest as the destination position of the mobile base station 200. Specifically, the distance between the pre-movement position and the post-movement position of the mobile base station 200 is set as a base station position evaluation index, and the post-movement position where the base station position evaluation index is the smallest is selected as the destination position of the mobile base station 200.

[0060] (S104) In S104, the base station control unit 150 moves the mobile base station 200 to the position selected in S103. Specifically, for example, the base station control unit 150 transmits to the mobile base station 200 information on the position where the mobile base station 200 should be placed and a command to instruct the mobile base station 200 to move to that position. The base station control unit 150 may further transmit to the mobile base station 200 identification information of each terminal to be connected to the mobile base station 200, and send an instruction to each terminal to transmit a control signal to connect to the mobile base station 200.

[0061] By the above-mentioned control, it becomes possible to control the movement range of the mobile base station within a range that satisfies the required quality.

[0062] Example 2 Next, a second embodiment will be described. In the second embodiment, a movable range is set, and a location with the highest base station position evaluation index within the range is selected. Examples of the base station position evaluation index are as described in the first embodiment.

[0063] An example of the operation of the control server 100 in the second embodiment will be described below with reference to the procedure of the flowchart in FIG.

[0064] (S201) In S201, the movable range of the mobile base station 200 is set for the control server 100. As an example, when the position before the mobile base station 200 is (m, n), a circle with a radius of d centered at (m, n) is set as the movable range. Information on the set movable range is stored in a storage means such as a memory of the control server 100, and is referred to by the base station control calculation unit 140.

[0065] (S202) In S202, the base station control calculation unit 140 calculates a base station position evaluation index for each possible location of the mobile base station 200 (e.g., for each possible area element), and calculates the possible location with the highest base station position evaluation index within the movable range as the destination location.

[0066] (S203) In S203, the base station control unit 150 moves the mobile base station 200 to the position selected in S202. Specifically, for example, the base station control unit 150 transmits to the mobile base station 200 information on the position where the mobile base station 200 should be placed and a command to instruct the mobile base station 200 to move to that position. The base station control unit 150 may further transmit to the mobile base station 200 identification information of each terminal to be connected to the mobile base station 200, and send an instruction to each terminal to transmit a control signal to connect to the mobile base station 200.

[0067] By setting the movement range of the mobile base station as described above, it becomes possible to maximize the communication quality within that range.

[0068] Example 3 Next, a description will be given of embodiment 3. In embodiment 3, in a method for arranging a mobile base station 200 at the center of gravity of a terminal cluster, outliers (bad terminals) are excluded when calculating the center of gravity.

[0069] An example of the operation of the control server 100 in the third embodiment will be described below with reference to the procedure of the flowchart in FIG.

[0070] (S301) In S301, the obstructing object information acquisition unit 120 acquires obstructing object information (position, material, etc.) from the spatial information DB 400, and the terminal information acquisition unit 130 acquires terminal 300 information (position of each terminal) from the spatial information DB 400.

[0071] (S302) In S302, the base station control calculation unit 140 takes into account the information on obstructions and divides the terminals 300 into a desired number of clusters. The details of this process will be described later.

[0072] (S303) In S303, the base station control unit 150 calculates, for each cluster, the destination position of the mobile base station 200. The calculation method will be described in detail later.

[0073] (S304) In S304, the base station control unit 150 moves the mobile base station 200 to the position selected in S303. Specifically, for example, the base station control unit 150 transmits to the mobile base station 200 information on the position where the mobile base station 200 should be placed and a command to instruct the mobile base station 200 to move to that position. The base station control unit 150 may further transmit to the mobile base station 200 identification information of each terminal to be connected to the mobile base station 200, and send an instruction to each terminal to transmit a control signal to connect to the mobile base station 200.

[0074] <How to generate a terminal cluster> The method of generating terminal clusters in S302 will be described in detail. The base station control calculation unit 140 takes into consideration obstacles and forms clusters starting from terminals with short inter-terminal distances. The specific processing procedure is as follows.

[0075] (S1) In S1, the base station control calculation unit 140 sets each terminal as a separate terminal cluster (initial).

[0076] (S2) In S2, the base station control calculation unit 140 obtains the distance between all the terminal clusters. The distance between the terminal clusters may be the average value of the distance between each pair of elements (terminals) between the two terminal clusters, the smallest value among the distance between each pair of elements (terminals) of the two terminal clusters, the largest value among the distance between each pair of elements (terminals) of the two terminal clusters, or any other statistical value.

[0077] The distance for each pair of elements (terminals) between two terminal clusters is, for example, when terminal cluster A has terminals A1 and A2 and terminal cluster B has terminals B1 and B2, the distance between terminal A1 and terminal B1, the distance between terminal A1 and terminal B2, the distance between terminal A2 and terminal B1, and the distance between terminal A2 and terminal B2.

[0078] An example of the distance between elements (terminals) between terminal clusters is as follows.

[0079] Let d(xn, xm) be the distance between terminal xn in one terminal cluster and terminal xm in another terminal cluster.

[0080] If there is an obstruction between xn and xm, d(xn,xm)=(Euclidean distance between xn and xm)+a×b a is the attenuation per thickness of the shield [m] (the converted distance of free space loss), and b is the thickness of the shield [m].

[0081] If there is no obstruction between xn and xm, d(xn,xm)=(Euclidean distance between xn and xm) Let us assume that.

[0082] (S3) The base station control calculation unit 140 combines the combination of terminal clusters with the smallest inter-terminal cluster distance to create a new terminal cluster.

[0083] (S4) The base station control calculation unit 140 repeats S2 and S3 until the desired number of terminal clusters is reached. The desired number of terminal clusters is the number of movable base stations 200. However, it is not limited to this.

[0084] Next, an example of a method for calculating the position of the movable base station 200 for each terminal cluster in S303 described above will be described.

[0085] <Example of method for calculating the position of the mobile base station 200> The base station control calculation unit 140 installs the mobile base station 200 at the center of gravity of the terminal cluster, taking into account the material and shape of the obstruction. When calculating the center of gravity, outliers (outlier terminals) are defined, and the center of gravity is found by excluding the outlier terminals.

[0086] Specifically, the position of the mobile base station 200 is calculated in the following procedure. The following procedure is executed for each terminal cluster.

[0087] (S1) In S1, the base station control calculation unit 140 obtains the center of gravity G of the terminal cluster. In S1, the weights of all elements (terminals) of the terminal cluster are set to 1.

[0088] Here, when calculating the center of gravity G, outliers (bad terminals) are excluded. For example, the center of gravity G is calculated once without excluding the bad terminals, and the distance between the center of gravity G and each terminal in the cluster is calculated, and one or more terminals whose distance is equal to or greater than a threshold (or equal to or less than the threshold) are determined as bad terminals. Then, the center of gravity G is calculated from the terminal cluster from which the bad terminals have been excluded. The threshold may be determined, for example, using the interquartile range, or the Smirnoff-Grubbs test, or by other methods.

[0089] Also, the speed and acceleration of each terminal are collected and stored in the spatial information DB 400, and the base station control calculation unit 140 is capable of acquiring the speed and acceleration of each terminal from the spatial information DB 400. In this case, the base station control calculation unit 140 may define terminals whose speed or acceleration is equal to or greater than a threshold as outlying terminals from the terminal cluster, and may find the center of gravity G by excluding them.

[0090] The terminal cluster in the following process is a terminal cluster excluding the outgoing terminals.

[0091] (S2) In S2, if there is an obstruction between the center of gravity G of the terminal cluster and an element of the terminal cluster, the base station control calculation unit 140 sets the weight of the element to d×b, where d is the weight for the amount of attenuation per thickness [m] of the obstruction, and b is the thickness [m] of the obstruction.

[0092] (S3) In S3, the base station control calculation unit 140 again calculates the center of gravity G' of the terminal cluster, and determines to place the mobile base station 200 at G'.

[0093] For example, the coordinates of the center of gravity G' are (x G ,y G ), and the unweighted position of terminal UEi is (x i ,y i), and the number of terminals in the cluster is n. For example, if there is an obstruction between the position (x3, y3) of terminal UE3 and the center of gravity G calculated in S1, then G'(x G ,y G ) can be calculated using the following formula:

[0094] G´(x G ,y G )=((x1+x2+dbx3+…+x n ) / (1+1+db+…+1),(y1+y2+dby3+…+y n ) / (1+1+db+…+1)) The method of calculating the weights and the method of adding the weights to the center of gravity are not limited to the above method, and other methods may be used.

[0095] With the above technology, if there is a bias in the distribution of terminal positions or speeds (acceleration), it is possible to reduce the movement range of base stations by eliminating that bias.

[0096] (Hardware configuration example) The control server 100 in this embodiment can be realized, for example, by making a computer execute a program in which the processing contents described in this embodiment are written. Note that this "computer" may be a physical machine or a virtual machine on the cloud. When a virtual machine is used, the "hardware" described here is virtual hardware.

[0097] The above program can be recorded on a computer-readable recording medium (such as a portable memory) and stored or distributed. The above program can also be provided via a network such as the Internet or email.

[0098] Fig. 11 is a diagram showing an example of the hardware configuration of the computer. The computer in Fig. 11 has 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, etc., which are all connected to each other via a bus B.

[0099] The program for realizing the 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.

[0100] The memory device 1003 reads out and stores the program from the auxiliary storage device 1002 when an instruction to start the program is received. The CPU 1004 realizes functions related to the control server 100 in accordance with the program stored in the memory device 1003. The interface device 1005 is used as an interface for connecting to a network. 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 and 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.

[0101] (Effects of the embodiment) The technology according to the present embodiment makes it possible to control communication quality and the moving range of a mobile base station. More specifically, it is possible to reduce the moving time of a mobile base station, and suppress the occurrence of periods in which communication quality deteriorates. Furthermore, if there is a bias in the distribution of terminal positions and velocities (acceleration), it is possible to suppress the moving range of a mobile base station by eliminating the bias.

[0102] (Summary of the embodiment) This specification discloses at least the following communication system, control server device, control method, and program. (Section 1) A communication system including a control server device and a mobile base station device, the control server device selects, as a destination location of the mobile base station device, a location where the moving distance from the current location of the mobile base station device is the smallest among the locations where the base station location evaluation index is equal to or greater than a threshold, or a location where the base station location evaluation index is the largest among the locations where the moving distance from the current location of the mobile base station device is equal to or less than a threshold, The control server device controls the movement of the mobile base station device to the destination position. Communication systems. (Section 2) The base station position evaluation index is the number of line-of-sight terminals, the number of line-of-sight area elements, the communication quality of the area elements, or the communication quality of the terminal. 2. A communication system as defined in claim 1. (Section 3) A communication system including a control server device and a mobile base station device, the control server device generates a terminal cluster by clustering the terminal devices based on the location of each terminal device; the control server device determines a stray terminal device based on the position, the speed, or the acceleration of each terminal device, and calculates a destination position of the mobile base station device based on a center of gravity position of the terminal cluster after excluding the stray terminal device from the terminal cluster; The control server device controls the movement of the mobile base station device to the destination position. Communication systems. (Section 4) A control server device in a communication system including a control server device and a mobile base station device, a base station control calculation unit that selects, as a destination location of the mobile base station device, a location where the moving distance from the current location of the mobile base station device is the smallest among the locations where the base station location evaluation index is equal to or greater than a threshold, or a location where the base station location evaluation index is the largest among the locations where the moving distance from the current location of the mobile base station device is equal to or less than a threshold; a base station control unit that controls the movement of the mobile base station device to the destination position; A control server device comprising: (Section 5) A control server device in a communication system including a control server device and a mobile base station device, a base station control calculation unit that generates a terminal cluster by clustering the terminal devices based on the position of each terminal device, determines a deviating terminal device based on the position, speed, or acceleration of each terminal device, and calculates a destination position of the mobile base station device based on a center of gravity position of the terminal cluster after excluding the deviating terminal device from the terminal cluster; a base station control unit that controls the mobile base station device to move to the destination position; A control server device comprising: (Section 6) A control method in a communication system including a control server device and a mobile base station device, a step of the control server device selecting, as a destination location of the mobile base station device, a location where the moving distance from the current location of the mobile base station device is the smallest among the locations where the base station location evaluation index is equal to or greater than a threshold, or a location where the base station location evaluation index is the largest among the locations where the moving distance from the current location of the mobile base station device is equal to or less than a threshold; a step of the control server device controlling the mobile base station device to move to the destination position; A control method comprising: (Section 7) A control method in a communication system including a control server device and a mobile base station device, The control server device generates a terminal cluster by clustering the terminal devices based on the location of each terminal device; The control server device determines a deviated terminal device based on the position, the speed, or the acceleration of each terminal device, and calculates a destination position of the mobile base station device based on a center of gravity position of the terminal cluster after excluding the deviated terminal device from the terminal cluster; a step of the control server device controlling the mobile base station device to move to the destination position; A control method comprising: (Section 8) A program for causing a computer to function as each unit in the control server device according to claim 4 or 5.

[0103] Although the present embodiment has been described above, the present invention is not limited to such a specific embodiment, and various modifications and variations are possible within the scope of the gist of the present invention described in the claims. [Explanation of symbols]

[0104] 100 Control Server 200 mobile base stations 300 terminals 400 Spatial information DB 110 Information and Communication I / F Section 120 Obstruction information acquisition unit 130 Terminal information acquisition unit 140 Base Station Control Calculation Unit 150 Base station control unit 160 Control communication I / F section 210 Control communication I / F section 220 Movable control section 230 Terminal connection control unit 240 Radio Transmitter / Receiver 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 communication system including a control server device and a mobile base station device, the control server device selects a position where a moving distance from the current position of the mobile base station device is the shortest among positions where a base station position evaluation index is equal to or greater than a threshold value as a moving destination position of the mobile base station device; The control server device controls the movement of the mobile base station device to the destination position. Communication systems.

2. The base station position evaluation index is the number of line-of-sight terminals, the number of line-of-sight area elements, the communication quality of the area elements, or the communication quality of the terminal. The communication system according to claim 1 .

3. A control server device in a communication system including a control server device and a mobile base station device, a base station control calculation unit that selects a position where a moving distance from a current position of the mobile base station device is the shortest among positions where a base station position evaluation index is equal to or greater than a threshold value as a moving destination position of the mobile base station device; a base station control unit that controls the movement of the mobile base station device to the destination position; A control server device comprising:

4. A control method in a communication system including a control server device and a mobile base station device, a step of the control server device selecting a position where a moving distance from a current position of the mobile base station device is the shortest among positions where a base station position evaluation index is equal to or greater than a threshold value as a moving destination position of the mobile base station device; a step of the control server device controlling the mobile base station device to move to the destination position; A control method comprising:

5. A program for causing a computer to function as each unit in the control server device according to claim 3.

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