Base station location selection method, base station location selection device, and program

Abstract

The present invention reduces imbalance in the number of terminals that are connected to each base station, by executing, via a computer, a calculation procedure in which for each of a plurality of candidates of a placement position for placing a second base station in an area where a first base station to which a plurality of terminals are connected is placed, the number of first terminals to be connected to the first base station and the number of second terminals to be connected to the second base station when the second base station is placed at the placement position corresponding to that candidate are calculated, and a selection procedure in which one candidate is selected from among the plurality of candidates on the basis of the number of the first terminals and the number of the second terminals.

Description

[Technical field]

[0001] The present invention relates to a base station installation position selection method, a base station installation position selection device, and a program. [Background technology]

[0002] If wireless base stations are evenly distributed throughout an area to efficiently ensure area coverage, it is possible that communication quality in a particular area may decline due to terminal congestion, obstruction, etc. In response to this, technology is being considered to dynamically distribute mobile base stations in areas where communication quality has declined to improve communication quality (Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Takuto Arai, Daisuke Goto, Masashi Iwabuchi, Tatsuhiko Iwakuni, Kazuki Maruta, "Proposal of an Adaptive Mobile AP System to Improve Offload Efficiency," IEICE Technical Report, vol. 116, no. 46, RCS2016-43, pp. 107-112, May 2016. Summary of the Invention [Problem to be solved by the invention]

[0004] However, when dynamically deploying a mobile base station, if the received power from that mobile base station becomes too high compared to other base stations, many terminals may autonomously connect to that mobile base station, resulting in excessive bias in terminal connections and a deterioration in communication quality.

[0005] Figure 1 is a diagram for explaining the problems with the conventional technology. In Figure 1, an example is explained in which one mobile base station is added to an environment in which one existing base station and six terminals exist. (1) in Figure 1 shows the state before the mobile base station is installed, and (2) shows the state after the mobile base station is installed.

[0006] Before the deployment of the mobile base station, six terminals were connected to one existing base station, causing congestion in communications, so the aim is to eliminate or alleviate the congestion by deploying one mobile base station.

[0007] In the conventional technology, as a result of calculating the arrangement of the mobile base station by clustering six terminals, for example, as in (2), the mobile base station is installed near the existing base station.

[0008] In this case, for five of the six terminals, the mobile base station is closer than the existing base station. Therefore, if the transmission power of the existing base station and the mobile base station is the same, the signal power received by these five terminals from the mobile base station will be greater than the signal power received from the existing base station.

[0009] In general wireless systems, when a terminal can receive signals from multiple base stations, it connects to the base station with the strongest reception power, so these five terminals connect to the mobile base station.

[0010] As a result, five terminals will be connected to the mobile base station and one terminal will be connected to the existing base station, resulting in an imbalance in the number of terminals connected between the existing base station and the mobile base station.

[0011] The present invention has been made in consideration of the above-mentioned points, and has an object to reduce the imbalance in the number of terminals connected to each base station. [Means for solving the problem]

[0012] In order to solve the above problem, a method is provided in which a computer executes a calculation step of calculating, for each of a plurality of candidates for the placement position of a second base station in an area in which a first base station to which a plurality of terminals are connected is placed, the number of first terminals connected to the first base station and the number of second terminals connected to the second base station when the second base station is placed in the placement position related to the candidate, and a selection step of selecting one candidate from the plurality of candidates based on the number of the first terminals and the number of the second terminals. and when a plurality of candidates are selected based on the number of the first terminals and the number of the second terminals, the selection step selects one candidate from the plurality of candidates based on a distance between the first base station and the first terminal that is farthest from the first base station among the first terminals and a distance between the second base station and the second base station among the second terminals. . Effect of the Invention

[0013] The imbalance in the number of terminals connected to each base station can be reduced. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a diagram for explaining a problem with the conventional technology. [Diagram 2] 1 is a diagram illustrating an example of a configuration of a communication system according to an embodiment of the present invention. [Diagram 3] 2 is a diagram illustrating an example of a hardware configuration of a control station 10 according to the embodiment of the present invention. [Figure 4] 2 is a diagram illustrating an example of a functional configuration of a control station 10 according to the first embodiment. FIG. [Diagram 5] 5 is a flowchart illustrating an example of a processing procedure executed by a control station 10 in the first embodiment. [Figure 6] FIG. 11 is a diagram illustrating an example of an arrangement candidate. [Figure 7] 13 is a diagram showing an example of a calculation result of an evaluation value X of each arrangement candidate in the first embodiment. FIG. [Figure 8] FIG. 11 is a diagram showing an example of a calculation result of an evaluation value Yi of each arrangement candidate in the first embodiment. [Figure 9] FIG. 2 is a diagram showing an example of a connection state of a terminal 50 to each base station according to the first embodiment. [Figure 10]FIG. 11 is a diagram illustrating an example of a functional configuration of a control station 10 according to a second embodiment. [Figure 11] 10 is a flowchart illustrating an example of a process procedure executed by a control station 10 in the second embodiment. [Figure 12] FIG. 13 is a diagram showing an example of a candidate pattern. [Figure 13] FIG. 11 is a diagram showing an example of a calculation result of an evaluation value X of each candidate pattern in the second embodiment. [Figure 14] FIG. 13 is a diagram showing an example of a calculation result of an evaluation value Yi of each candidate pattern in the second embodiment. [Figure 15] FIG. 11 is a diagram showing an example of a connection state of a terminal 50 to each base station according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 2 is a diagram showing an example of the configuration of a communication system in an embodiment of the present invention. As shown in Fig. 2, a communication system 1 includes one or more existing base stations 30, one or more mobile base stations 20, one or more relay base stations 40, a control station 10, etc. Note that a base station refers to a base station (access point) for wireless communication (for example, wireless LAN).

[0016] In this embodiment, the existing base station 30 is an already installed base station. In this embodiment, the existing base station 30 is not a target for movement, but the existing base station 30 may be movable.

[0017] The mobile base station 20 is a mobile base station, and in this embodiment, is a base station that is newly deployed (the deployment location has not been decided). For example, when communication is congested at an existing base station 30, the mobile base station 20 is dynamically deployed. The driving means for moving the mobile base station 20 is not limited to a specific one. For example, the driving means may be a vehicle or a drone. The mobile base station 20 may also be configured to move on rails that have been laid in advance.

[0018] The relay base station 40 is a base station that relays communication between the mobile base station 20 and the control station 10. The relay base station 40 is connected to the mobile base station 20 by wireless communication. Therefore, the mobile base station 20 is movable within a range where wireless communication with the relay base station 40 is possible.

[0019] In the following, when there is no need to distinguish between the existing base station 30 and the mobile base station 20, they are simply referred to as "base station." Although not shown in the figure, there are multiple terminals (hereinafter, terminals 50) that wirelessly connect to any of the base stations and communicate. Each terminal connects to any of the base stations through autonomous control. The autonomous control is, for example, a control in which a terminal connects to a base station with a relatively large reception power at the terminal.

[0020] The control station 10 is one or more computers that control the placement of the mobile base stations 20. The control station 10 is connected to each of the existing base stations 30 and each of the relay base stations 40 via a network (whether wired or wireless), and can collect information on each of the base stations and terminals from each of the existing base stations 30 and each of the relay base stations 40.

[0021] Fig. 3 is a diagram showing an example of a hardware configuration of a control station 10 in an embodiment of the present invention. The control station 10 in Fig. 3 includes a drive device 100, an auxiliary storage device 102, a memory device 103, a CPU 104, and an interface device 105, which are all connected to each other via a bus B.

[0022] A program for implementing the processing in the control station 10 is provided by a recording medium 101 such as a CD-ROM. When the recording medium 101 storing the program is set in the drive device 100, the program is installed from the recording medium 101 to the auxiliary storage device 102 via the drive device 100. However, the program does not necessarily have to be installed from the recording medium 101, but may be downloaded from another computer via a network. The auxiliary storage device 102 stores the installed program as well as necessary files, data, and the like.

[0023] When an instruction to start a program is received, the memory device 103 reads out the program from the auxiliary storage device 102 and stores it. The CPU 104 executes functions related to the control station 10 in accordance with the program stored in the memory device 103. The interface device 105 is used as an interface for connecting to a network.

[0024] Fig. 4 is a diagram showing an example of a functional configuration of the control station 10 in the first embodiment. In Fig. 4, the control station 10 has a generation unit 11, a calculation unit 12, a selection unit 13, and an arrangement unit 14. Each of these units is realized by a process in which one or more programs installed in the control station 10 are executed by the CPU 104.

[0025] The following describes the process steps executed by the control station 10. Fig. 5 is a flowchart for explaining an example of the process steps executed by the control station 10 in the first embodiment.

[0026] In step S100, the generation unit 11 generates (sets) a plurality of candidates (hereinafter referred to as "placement candidates") for the placement position of the mobile base station 20 within an area (hereinafter referred to as "target area") in which the mobile base station 20 is to be placed. The placement candidates specifically refer to data indicating the positions of the placement candidates. The positions may be indicated by latitude and longitude, etc., or may be indicated by a relative positional relationship in the target area. The range of the target area may be determined in advance either manually or automatically. In the first embodiment, it is assumed that there is one existing base station 30 in the target area (hereinafter, the existing base station 30 is referred to as the "target existing base station 30"), and one mobile base station 20 to be placed (newly installed).

[0027] Fig. 6 is a diagram showing an example of placement candidates. In Fig. 6, placement candidates in a target area A are shown by dashed circles. Fig. 6 also shows placement positions of a target existing base station 30 and each terminal 50. Note that the dashed line connecting the existing base station 30 and the terminal 50 indicates a wireless connection relationship between the existing base station 30 and the terminal 50.

[0028] The generation unit 11 may generate layout candidates at equal intervals in the vertical and horizontal directions (for example, the north-south and east-west directions) within the target area A, or may generate layout candidates based on other rules.

[0029] Next, the calculation unit 12 calculates evaluation parameters for each placement candidate based on the location of each base station (the movable base station 20 and the existing base station 30) and the location of each terminal 50 (each terminal 50 connected to the target base station) (S102). In this embodiment, the evaluation parameters are (a) the number of terminals connected to the existing base station, (b) the number of terminals connected to the movable base station, and (c) terminals that cannot be connected to a base station.

[0030] The (a) number of connected terminals of an existing base station for a certain placement candidate refers to the number of terminals 50 that will connect to the target existing base station 30 when the mobile base station 20 is placed in the placement candidate.

[0031] The (b) number of connected terminals of a mobile base station of a certain deployment candidate refers to the number of terminals 50 that will connect to the mobile base station 20 when the mobile base station 20 is deployed in the deployment candidate.

[0032] The (c) base station connection incapable terminal of a certain placement candidate refers to a terminal 50 that cannot connect to either the movable base station 20 or the target existing base station 30 when the mobile base station 20 is placed in the placement candidate. The value of (c) is 0 when a terminal 50 corresponding to the base station connection incapable terminal exists, and is 1 when a terminal 50 corresponding to the base station connection incapable terminal does not exist.

[0033] Regarding (a) and (b), the calculation unit 12 calculates the received power at each terminal 50 from the target existing base station 30 and the movable base station 20 based on the distance between each terminal 50 and the target existing base station 30 and each movable base station 20, and the transmission power of each of the target existing base station 30 and the movable base station 20, and calculates the number of connected terminals for each base station when the terminal 50 is connected to the base station with the highest received power. At this time, the transmission power of the movable base station 20 may be a default value different from the transmission power of the target existing base station 30, or may be the same value as the transmission power of the target existing base station 30.

[0034] Regarding (c), the calculation unit 12 determines as a result whether or not there is a terminal 50 for which the maximum value of the received power calculated for each base station for each terminal 50 regarding (a) and (b) (the maximum value of the received power from the target existing base station 30 and the received power from the movable base station 20) is below a predetermined threshold value (required received power).

[0035] Next, the calculation unit 12 calculates an evaluation value X for each arrangement candidate based on (a) to (c) (S103). Here, as an example, the product of (a), (b), and (c) ((a)×(b)×(c)) is calculated as the evaluation value X.

[0036] Fig. 7 is a diagram showing an example of the calculation result of the evaluation value X of each arrangement candidate in the first embodiment. Fig. 7 shows an arrangement candidate number, an example of the values ​​(a) to (c), and an example of the evaluation value X for each arrangement candidate. Note that the arrangement candidate number is an identification number for each arrangement candidate, and is associated with the arrangement position. However, the arrangement candidate number may also indicate the position of the arrangement candidate.

[0037] Next, the selection unit 13 judges whether there are multiple placement candidates with the maximum evaluation value X (S104). If there is one placement candidate with the maximum evaluation value X (N in S104), the selection unit 13 selects the placement candidate (S105) and proceeds to step S113. Note that the placement candidate with the maximum evaluation value X is a placement candidate with a small imbalance in the number of connected terminals between base stations and with no terminals that cannot connect to a base station, and therefore it is possible to identify a placement position with a small imbalance in terminal connections for the mobile base station 20.

[0038] On the other hand, if there are multiple placement candidates with the maximum evaluation value X (i.e., the placement candidate cannot be uniquely selected with the evaluation value X) (Y in S105), the selection unit 13 calculates (d) the maximum value of the distance between the existing base station connected terminal and the existing base station, and (e) the maximum value of the distance between the movable base station connected terminal and the movable base station for each placement candidate with the maximum evaluation value X, and sets the i-th (i=1, 2) value (i.e., the i-th largest value) of (d) and (e) in descending order as the evaluation value Yi of the placement candidate (S106). Note that the existing base station connected terminal in a certain placement candidate refers to the terminal 50 (the terminal 50 whose receiving power from the target existing base station 30 is greater than that from the movable base station 20) that will connect to the target existing base station 30 when the movable base station 20 is placed in the placement candidate. Furthermore, a mobile base station connected terminal in a certain placement candidate refers to a terminal 50 that will connect to the mobile base station 20 when the mobile base station 20 is placed in that placement candidate (a terminal 50 whose received power from the mobile base station 20 is greater than that from the target existing base station 30). Therefore, (d) is the distance between the terminal 50 that is farthest from the target existing base station 30 and the target existing base station 30 among the terminals 50 that connect to the target existing base station 30. (e) is the distance between the mobile base station 20 and the terminal 50 that is farthest from the mobile base station 20 among the terminals 50 that connect to the mobile base station 20.

[0039] Fig. 8 is a diagram showing an example of the calculation result of the evaluation value Yi of each allocation candidate in the first embodiment. Fig. 8 further shows, for multiple allocation candidates with the largest evaluation value X, (d) the maximum distance between the existing base station connected terminal and the existing base station, (e) the maximum distance between the movable base station connected terminal and the movable base station, and the evaluation value Yi (evaluation value Y1, evaluation value Y2). The evaluation value Y1 is the larger of (d) and (e). The evaluation value Y2 is the smaller of (d) and (e).

[0040] Next, the selection unit 13 assigns 1 to the variable i (S107). Next, the selection unit 13 determines whether or not there are multiple layout candidates with the smallest evaluation value Yi (S108). If there is only one layout candidate with the smallest evaluation value Yi (N in S108), the selection unit 13 selects that layout candidate (S109) and proceeds to step S113.

[0041] On the other hand, if there are multiple layout candidates with the smallest evaluation value Yi (Y in S108), the selection unit 13 selects the layout candidate with the smallest evaluation value Yi (Y in S108). max It is determined whether or not the number of characters matches the number of characters (S110). max is the total number of the target existing base stations 30 and the mobile base stations 20 (here, 2). max If it does not match (N in S110), the selection unit 13 adds 1 to i (S111) and repeats step S108 and subsequent steps.

[0042] i is i max If it matches (Y in S110), the selection unit 13 selects the placement candidate that is first in the sorting order in Fig. 8 (has the smallest placement candidate number) from among the placement candidates with the smallest evaluation value Yi (S112), and proceeds to step S113. By steps S106 and onwards, it is possible to select a placement candidate with a smaller maximum distance to the terminal 50. According to the example in Fig. 8, the placement candidate with placement candidate number 7 is selected.

[0043] In step S113, the allocation unit 14 controls the allocation of the movable base station 20 to the allocation position related to the allocation candidate selected in step S105, S109 or S112. By arranging the movable base station 20, the connection state of the terminals 50 to each base station becomes, for example, as shown in Fig. 9. In Fig. 9, three terminals 50 are connected to the existing base station 30, and three terminals 50 are connected to the movable base station 20, and none of the base stations are congested (the congestion of the existing base station 30 has been resolved).

[0044] As described above, according to this embodiment, it is possible to reduce the imbalance in the number of terminals connected to each base station, which is expected to improve communication quality.

[0045] In the above, an example in which there is one existing base station 30 and one movable base station 20 has been described, but the first embodiment may be applied to a case in which there are multiple existing base stations 30 or multiple movable base stations 20. When there are multiple movable base stations 20, a placement candidate may be generated for each combination of placement positions of the multiple movable base stations 20.

[0046] Next, a second embodiment will be described. In the second embodiment, differences from the first embodiment will be described. Points not specifically mentioned in the second embodiment may be the same as those in the first embodiment.

[0047] In the second embodiment, an example will be described in which there are a plurality of each of the existing base stations 30 and the movable base stations 20 (specifically, two of each). Also, in the second embodiment, not only the location of each movable base station 20 but also the transmission power of each movable base station 20 is made variable, thereby searching for a combination of the location and transmission power of the movable base station 20 that has less bias in the number of connected terminals.

[0048] Fig. 10 is a diagram showing an example of a functional configuration of the control station 10 in the second embodiment. In Fig. 10, parts that are the same as or correspond to those in Fig. 4 are given the same reference numerals. In the second embodiment, the control station 10 further includes a setting unit 15. The setting unit 15 is realized by a process in which one or more programs installed in the control station 10 are executed by the CPU 104.

[0049] Fig. 11 is a flowchart for explaining an example of a processing procedure executed by the control station 10 in the second embodiment. In Fig. 11, steps that are the same as or correspond to those in Fig. 5 are given the same step numbers, and their explanations will be omitted as appropriate.

[0050] Following step S100, the generation unit 11 generates a plurality of combinations (hereinafter referred to as "candidate patterns") of a plurality of placement candidates for each mobile base station 20 and a plurality of transmission power adjustment amounts for each mobile base station 20 (S101). The transmission power adjustment amount refers to the relative amount of power reduction from the maximum transmission power. For example, since the settable transmission power differs depending on the country, in this embodiment, it is a relative value based on the maximum value. However, the absolute value of the transmission power may be used instead of the transmission power adjustment amount.

[0051] FIG. 12 is a diagram showing an example of a candidate pattern. As shown in FIG. 12, one candidate pattern includes a candidate pattern number, an arrangement candidate sequence, and a transmission power adjustment amount sequence. The candidate pattern number is an identification number of the candidate pattern. The arrangement candidate sequence is a combination of arrangement candidates (arrangement candidate numbers) for each mobile base station 20. For example, the first 1 in the arrangement candidate sequence [1,2] for candidate pattern number=1 indicates an arrangement candidate number for one mobile base station 20, and the second 2 indicates an arrangement candidate number for the other mobile base station 20. The transmission power adjustment amount sequence is a combination of transmission power adjustment amounts for each mobile base station 20. For example, the first 0 in the transmission power adjustment amount sequence [0,0] for candidate pattern number=1 indicates a transmission power adjustment amount for one mobile base station 20, and the second 0 indicates a transmission power adjustment amount for the other mobile base station 20.

[0052] In steps S102 and S103, the calculation unit 12 calculates parameters (a) to (c) for each candidate pattern in which each movable base station 20 is arranged at the arrangement position indicated by the arrangement candidate sequence related to the candidate pattern, and each movable base station 20 outputs the transmission power indicated by the transmission power adjustment amount sequence related to the candidate pattern, to calculate an evaluation value X. Note that the calculation unit 12 calculates (a) the number of connected terminals of the existing base station for each existing base station 30. (b) The number of connected terminals of the movable base station is calculated for each movable base station 20. Therefore, in this embodiment, two values ​​are calculated for each of (a) and (b). Moreover, the evaluation value X is calculated by multiplying all of (a), all of (b), and (c). Therefore, the evaluation value X becomes one value for each candidate pattern.

[0053] Fig. 13 is a diagram showing an example of the calculation result of the evaluation value X of each candidate pattern in the second embodiment. Fig. 13 shows an example of the values ​​(a) to (c) and an example of the evaluation value X for each candidate pattern. Note that, among the two values ​​[x, y] in (a), x is a value for one of the two existing base stations 30, and y is a value for the other of the two existing base stations 30. Similarly, among the two values ​​[x, y] in (b), x is a value for one of the two movable base stations 20, and y is a value for the other of the two movable base stations 20.

[0054] If there is one candidate pattern with the maximum evaluation value X (N in S104), the selection unit 13 selects that candidate pattern (S105) and proceeds to step S113a.

[0055] On the other hand, if there are multiple candidate patterns with the maximum evaluation value X (Y in S105), the selection unit 13 calculates (d) the minimum value of the received power of the terminal connected to the existing base station and (e) the minimum value of the received power of the terminal connected to the movable base station for each candidate pattern with the maximum evaluation value X, and sets the i-th smallest value of (d) and (e) as the evaluation value Yi (S106a). Note that (d) the minimum value of the received power of the terminal connected to the existing base station refers to the minimum value of the power of the signal received from the existing base station 30 at each existing base station connected terminal. (e) the minimum value of the received power of the terminal connected to the movable base station refers to the minimum value of the power of the signal received from the movable base station 20 at each mobile base station connected terminal. Note that the received power at the terminal 50 from each base station can be calculated based on the distance between each base station and the terminal 50 and the transmission power of each base station, etc.

[0056] Fig. 14 is a diagram showing an example of the calculation result of the evaluation value Yi of each candidate pattern in the second embodiment. Fig. 14 further shows, for the candidate pattern with the maximum evaluation value X, (d) the minimum value of the received power of the terminal connected to the existing base station, (e) the minimum value of the received power of the terminal connected to the movable base station, the evaluation value Y1, and the evaluation value Y2.

[0057] In step S108a, the selection unit 13 determines whether there is a plurality of candidate patterns with the maximum evaluation value Yi. If there is one candidate pattern with the maximum evaluation value Yi (N in S108a), the selection unit 13 selects the candidate pattern (S109a) and proceeds to step S113a.

[0058] On the other hand, if there are multiple candidate patterns with the maximum evaluation value Yi (Y in S108a), the selection unit 13 selects the candidate pattern with the maximum evaluation value Yi. max It is determined whether or not the number of characters matches the number of characters (S110). max is the total number of target existing base stations 30 and mobile base stations 20 (here, 4). max If it does not match (N in S110), the selection unit 13 adds 1 to i (S111) and repeats step S108a and subsequent steps.

[0059] i is i max8 (having the smallest candidate pattern number) among the candidate patterns having the largest evaluation value Yi (Y in S110), the selection unit 13 selects (S112a) the candidate pattern which is first in the sorting order in Fig. 8 (having the smallest candidate pattern number) and proceeds to step S113a. By steps S106a and onwards, it is possible to select a candidate pattern having a larger minimum received power at the terminal 50. According to the example in Fig. 14, the candidate pattern having the candidate pattern number 29 is selected.

[0060] In step S113a, the placement unit 14 controls placement of each mobile base station 20 to the placement positions indicated by the placement candidate sequence of the candidate pattern selected in step S105, S109a or S112a.

[0061] Next, the setting unit 15 sets the transmission power adjustment amount in the transmission power adjustment amount sequence of the selected candidate pattern to each mobile base station 20 (S114). As a result, the connection state of the terminals 50 to each base station becomes, for example, as shown in Fig. 15. In Fig. 15, two terminals 50 are connected to the existing base station 30-1, one terminal 50 is connected to the existing base station 30-2, two terminals 50 are connected to the mobile base station 20-1, and one terminal 50 is connected to the mobile base station 20-2, and none of the base stations are congested.

[0062] As described above, according to the second embodiment, it is possible to obtain the same effects as those of the first embodiment.

[0063] If the base station can set different transmission powers for the beacon signal and the data signal, the transmission power may be reduced only for the beacon signal without reducing the signal transmission power for the data signal.

[0064] In addition, the placement options for the mobile base station 20 may be limited in advance, taking into consideration the communication area of ​​the backhaul line that accommodates the mobile base station 20.

[0065] Furthermore, if the height of the mobile base station 20 can be adjusted, multiple placement options for the mobile base station 20 in the height direction may also be prepared.

[0066] Furthermore, when the mobile base station 20 can change the beam transmission direction (such as the direction of analog beamforming or the selection of antenna patterns for digital beamforming), the candidate patterns may be further differentiated depending on when the beam transmission direction is switched.

[0067] Moreover, each of the above-mentioned embodiments may be applied not only to the mobile base station 20 but also to the arrangement of fixed base stations. For example, the present embodiment may be applied to the determination of the arrangement position and transmission power of a newly established fixed base station.

[0068] In each of the above embodiments, the existing base station 30 is an example of a first base station, the movable base station 20 is an example of a second base station, and the control station 10 is an example of a base station installation position selecting device.

[0069] Although the embodiment of the present invention has been described in detail above, the present invention is not limited to such 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]

[0070] 1. Communication Systems 10 Control Station 11 Generation part 12 Calculation section 13 Selection section 14 Placement section 15 Setting section 20 Mobile base station 30 Existing base stations 40 Relay base station 50 terminals 100 Drive device 101 Recording media 102 Auxiliary storage 103 Memory device 104 CPU 105 Interface device B Bus

Claims

1. a calculation step of calculating, for each of a plurality of candidates for the location of a second base station in an area in which a first base station to which a plurality of terminals are connected is located, the number of first terminals connected to the first base station and the number of second terminals connected to the second base station when the second base station is located at the location related to the candidate; a selection step of selecting one candidate from the plurality of candidates based on the number of the first terminals and the number of the second terminals; The computer executes the selection step, when a plurality of candidates are selected based on the number of the first terminals and the number of the second terminals, selects one candidate from the plurality of candidates based on a distance between the first base station and the first terminal, which is the farthest from the first base station among the first terminals, and a distance between the second base station and the second base station, which is the farthest from the second base station among the second terminals; A base station installation position selection method comprising:

2. A calculation procedure for calculating, for each of a plurality of candidates for the location of a second base station in an area in which a first base station to which a plurality of terminals are connected is located, the number of first terminals connected to the first base station and the number of second terminals connected to the second base station when the second base station is located at the location related to the candidate; a selection step of selecting one candidate from the plurality of candidates based on the number of the first terminals and the number of the second terminals; The computer executes The calculation step further includes calculating, for each of a plurality of combinations of a plurality of candidates for the arrangement position and a plurality of candidates for the transmission power of the second base station, the number of the first terminals and the number of the second terminals when the second base station is arranged at an arrangement position related to the combination and the second base station outputs the transmission power related to the combination; the selection step includes selecting one combination from the plurality of combinations based on the number of the first terminals and the number of the second terminals. A base station installation position selection method comprising:

3. the selection step, when it is not possible to select an arrangement position of the second base station based on the number of the first terminals and the number of the second terminals, selects one combination from the plurality of combinations based on a minimum value of reception power of the first terminal from the first base station and a minimum value of reception power of the second terminal from the second base station; 3. The method for selecting a base station location according to claim 2.

4. a calculation unit that calculates, for each of a plurality of candidates for a location of a second base station in an area in which a first base station to which a plurality of terminals are connected is located, the number of first terminals that will connect to the first base station and the number of second terminals that will connect to the second base station when the second base station is located at the location related to the candidate; a selection unit that selects one candidate from among the plurality of candidates based on the number of the first terminals and the number of the second terminals; having when a plurality of candidates are selected based on the number of the first terminals and the number of the second terminals, the selection unit selects, for each of the plurality of candidates, one candidate from the plurality of candidates based on a distance between the first base station and the first terminal that is farthest from the first base station among the first terminals, and a distance between the second base station and the second terminal that is farthest from the second base station among the second terminals; A base station installation position selecting device comprising:

5. A calculation unit that calculates, for each of a plurality of candidates for the placement position of a second base station in an area in which a first base station to which a plurality of terminals are connected is located, the number of first terminals that will be connected to the first base station and the number of second terminals that will be connected to the second base station when the second base station is placed at the placement position related to the candidate; a selection unit that selects one candidate from among the plurality of candidates based on the number of the first terminals and the number of the second terminals; having the calculation unit further calculates, for each of a plurality of combinations of a plurality of candidates for the arrangement position and a plurality of candidates for the transmission power of the second base station, the number of the first terminals and the number of the second terminals in a case where the second base station is arranged at an arrangement position related to the combination and the second base station outputs the transmission power related to the combination; the selection unit selects one combination from the plurality of combinations based on the number of the first terminals and the number of the second terminals. A base station installation position selecting device comprising:

6. 4. A program for causing a computer to execute the base station installation position selection method according to claim 1.

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