Layout Design Support Method

Abstract

To provide a technique for enabling more effective station installation design within an actual calculation processing time.SOLUTION: A station installation design support method has the steps of: acquiring information representing the location of at least one first radio station; calculating the number of combination patterns of at least one first radiatio station and an installation candidate positions of at least one second radio station located within a predetermined distance from the position of the first radio station; making the predetermined distance shorter stepwise when the number of combination patterns exceeds a predetermined number; and outputting the number of combination patterns when the number of combination patterns does not exceed the predetermined number any more.SELECTED DRAWING: Figure 23

Description

Technical Field

[0001] The present invention relates to a method for assisting in the design of a location station.

Background Art

[0002] FIG. 26 is a diagram schematically modified with reference to a use case proposed by mmWave Networks (see, for example, Non-Patent Documents 1 to 3) in TIP (Telecom Infra Project), a consortium aiming to promote the opening of specifications for all communication network devices (major members: Facebook, Deutsche Telecom, Intel, Nokia, etc.). mmWave Networks is one of the project groups of TIP and aims to construct a network faster and at lower cost than laying optical fibers using unlicensed band millimeter-wave radio.

[0003] In buildings such as buildings 800, 801 and houses 810, 811, 812 shown in FIG. 26, terminal station devices 840 to 844 (hereinafter referred to as "terminal stations") installed on the respective wall surfaces of the buildings and base station devices 830 to 834 (hereinafter referred to as "base stations") installed on utility poles 821 to 826 are devices called mmWave DNs (Distribution Nodes).

[0004] Base stations 830 to 834 are connected to communication devices provided in fiber points of presence (Fiber PoP) 850 and 851 by optical fibers 900 and 901. This communication device is connected to the provider's communication network. Between terminal stations 840 to 844 and base stations 830 to 834, mmWave Link, that is, millimeter-wave radio is performed. In FIG. 26, the link of the millimeter-wave radio is indicated by a dashed line.

[0005] In a form where base stations 830 to 834 are installed on utility poles 821 to 826, terminal stations 840 to 844 are installed on the wall surfaces of buildings, and communication between the two stations is performed by millimeter-wave wireless, the selection of positions that are candidates for installing base stations 830 to 834 and terminal stations 840 to 844 is called station placement design.

[0006] As a method for performing station placement design, there is a method that uses three-dimensional point cloud data obtained by imaging space. In this method, for example, first, a moving object such as a vehicle equipped with an MMS (Mobile Mapping System) is driven along the road around the housing area to be evaluated to acquire three-dimensional point cloud data. Next, the acquired point cloud data is utilized to evaluate the wireless communication between base stations 830 to 834 and terminal stations 840 to 844. As evaluation means, there are means for performing three-dimensional line-of-sight determination between the two stations and means for calculating the shielding rate. Here, the "shielding rate" is an index indicating the degree to which an object existing between base stations 830 to 834 and terminal stations 840 to 844 affects wireless communication, and from the reverse perspective, it can also be called the "transmittance". In order to perform these evaluation means, in the space including the candidate positions of base stations 830 to 834 and terminal stations 840 to 844, it is necessary to have point cloud data for all evaluation targets.

Prior Art Documents

Non-Patent Documents

[0007]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0008] When trying to cover a certain area (such as a city) with the communication network as described above, in order to plan for facility investment and the like, a wireless communication carrier needs to roughly grasp the number of base stations required. For example, as shown in FIG. 26, when performing a station placement design such that a base station is installed on a utility pole and a terminal station is installed on the wall surface of a building, an area of several hundred meters square may be set as the evaluation target area. In such a case, if line-of-sight determination and shielding rate calculation processing are performed for all combination patterns of all candidate base station installation positions (i.e., utility poles) and all candidate terminal station installation positions (i.e., building wall surfaces) existing within the evaluation target area, an enormous amount of calculation will be involved. Therefore, conventionally, in order to reduce the number of combination patterns to a number that can be processed within a realistic calculation processing time, for example, the evaluation target area is divided into a plurality of smaller areas (hereinafter referred to as "small areas"), and station placement design is performed for each small area.

[0009] However, when station placement design is performed for each small area, combination patterns of candidate base station installation positions and candidate terminal station installation positions that exist across the boundary between two adjacent small areas will be excluded from evaluation even if, for example, they are combination patterns with line-of-sight between the two stations and a low shielding rate. Thus, in the prior art, there is a problem that effective station placement design may not be performed because combination patterns with line-of-sight between the two stations and a low shielding rate may be overlooked.

[0010] In view of the above circumstances, an object of the present invention is to provide a technique that enables more effective station placement design within a realistic calculation processing time.

Means for Solving the Problem

[0011] One aspect of the present invention includes steps of obtaining information indicating the position of at least one first radio station, calculating the number of combination patterns of at least one first radio station and installation candidate positions of at least one second radio station located within a predetermined distance from the position of the first radio station, when the number of the combination patterns exceeds a predetermined number, stepwise shortening the predetermined distance, and when the number of the combination patterns no longer exceeds the predetermined number, outputting the number of the combination patterns. This is a method for supporting station placement design.

[0012] One aspect of the present invention includes steps of obtaining information indicating the position of at least one first radio station, calculating the number of combination patterns of at least one first radio station and installation candidate positions of at least one second radio station located within a predetermined distance from the position of the first radio station, when the number of the combination patterns does not exceed a predetermined number, stepwise lengthening the predetermined distance, and when the number of the combination patterns exceeds the predetermined number, outputting the number of the combination patterns based on the predetermined distance at the immediately preceding step. This is a method for supporting station placement design.

Advantages of the Invention

[0013] According to the present invention, it becomes possible to perform a more effective station placement design within a realistic calculation processing time.

Brief Description of the Drawings

[0014]

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Embodiments for Carrying Out the Invention

[0015] (First Embodiment) Hereinafter, the first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a station placement design support device 1 that supports the station placement design of the first embodiment. The station placement design support device 1 includes a design area designating unit 2, a base station candidate position extraction unit 3, a terminal station candidate position extraction unit 4, a two-dimensional line-of-sight determination processing unit 5, a point cloud data processing unit 6, a number of stations calculation unit 7, an operation processing unit 10, a map data storage unit 11, a facility data storage unit 12, a point cloud data storage unit 13, a two-dimensional line-of-sight determination result storage unit 15, a pattern number control unit 17, and a combination pattern list storage unit 18.

[0016] The point cloud data processing unit 6 includes a three-dimensional candidate position selection unit 20, a three-dimensional line-of-sight determination processing unit 23, and a shielding rate calculation unit 24. The pattern number control unit 17 includes an area division unit 171, a combination pattern extraction unit 172, a duplicate pattern deletion unit 173, and a recommended pattern specifying unit 174.

[0017] The data pre-stored in the map data storage unit 11, the facility data storage unit 12, and the point cloud data storage unit 13 included in the station placement design support device 1 will be described.

[0018] The map data storage unit 11 stores two-dimensional map data in advance. The map data includes, for example, data indicating the positions and shapes of buildings that are candidates for installing terminal stations, data indicating the ranges of the building sites, and data indicating roads. The facility data storage unit 12 stores base station candidate position data (hereinafter referred to as "two-dimensional base station candidate position data") in a two-dimensional coordinate system indicating the positions of base station installation structures, such as utility poles, which are outdoor facilities that are candidates for installing base stations. The point cloud data storage unit 13 stores, for example, three-dimensional point cloud data acquired by the MMS.

[0019] Hereinafter, with reference to the flowchart shown in FIG. 2, the configurations of the functional units of the station placement design support device 1 and the processing flow of the station placement design support method by the station placement design support device 1 will be described.

[0020] The design area specifying unit 2 reads two-dimensional map data from the map data storage unit 11 (step S1-1). The design area specifying unit 2 writes the read map data into, for example, the working memory for storage. The design area specifying unit 2 selects a rectangular area based on, for example, an instruction signal for specifying the range of the design area output by the operation processing unit 10 in response to the operation of the user of the station placement design support device 1 in the map data stored in the working memory. The design area specifying unit 2 designates the selected area as the design area (step S1-2).

[0021] The terminal station candidate position extraction unit 4 extracts building outline data indicating the positions and shapes of buildings from the map data within the design area for each building (step S2-1). The building outline data extracted by the terminal station candidate position extraction unit 4 is data indicating the wall surfaces of buildings where terminal stations may be installed and is regarded as positions that are candidates for installing terminal stations.

[0022] The terminal station candidate position extraction unit 4 generates and assigns building identification data, which is identification information capable of uniquely identifying each building, to the building outline data for each building to be extracted. The terminal station candidate position extraction unit 4 outputs by associating the assigned building identification data with the building outline data corresponding to the building.

[0023] The base station candidate position extraction unit 3 reads out and outputs two-dimensional base station candidate position data corresponding to the base station installation buildings located within the design area designated by the design area designation unit 2 from the facility data storage unit 12 (step S3-1). When the coordinates of the map data stored in the map data storage unit 11 do not match the coordinates of the two-dimensional base station candidate position data stored in the facility data storage unit 12, the base station candidate position extraction unit 3 performs a conversion to align the coordinates of the read two-dimensional base station candidate position data with the coordinate system of the map data.

[0024] For each of the two-dimensional base station candidate position data output by the base station candidate position extraction unit 3, the two-dimensional line-of-sight determination processing unit 5 uses the building outline data for each building output by the terminal station candidate position extraction unit 4 to determine the presence or absence of line-of-sight for each building in the horizontal direction from the position indicated by each of the two-dimensional base station candidate position data. The two-dimensional line-of-sight determination processing unit 5 detects the range with line-of-sight in the building determined to have line-of-sight, that is, the wall surface of the building as the line-of-sight range (step S4-1).

[0025] The two-dimensional line-of-sight determination processing unit 5 further preferentially selects candidates for the wall surface of the building where the terminal station is to be installed from among the wall surfaces of the building corresponding to the detected line-of-sight range. When the line-of-sight range of a certain building includes a plurality of wall surfaces, for example, the wall surface closer to the base station is preferentially selected as the wall surface for installing the terminal station, and the wall surface is selected as the final line-of-sight range in the horizontal direction.

[0026] Note that when the line-of-sight range of a certain building includes a plurality of wall surfaces, the method of selecting one wall surface is not limited to the above method and is arbitrary.

[0027] The two-dimensional line-of-sight determination processing unit 5 associates the building outline data of the building having the line-of-sight range detected in the horizontal direction with the data indicating the line-of-sight range of the building in the horizontal direction for each candidate base station position, and writes and stores the data in the two-dimensional line-of-sight determination result storage unit 15 (step S4-2). As a result, for each two-dimensional candidate base station position data, the building identification data of the building and the data indicating the horizontal line-of-sight range of the building corresponding to the building identification data are stored in the two-dimensional line-of-sight determination result storage unit 15.

[0028] The two-dimensional line-of-sight determination processing unit 5 determines whether it has received from the operation processing unit 10 an instruction signal indicating an "instruction to consider a building in which another building exists between the candidate base station position" output by the operation processing unit 10 in response to the operation of the user of the station placement design support device 1 (step S4-3). Note that before the processing of FIG. 2 is started, the user of the station placement design support device 1 has previously selected whether to consider a building in which another building exists between the candidate base station position. If the user has selected to consider it, the operation processing unit 10 outputs an instruction signal indicating an "instruction to consider a building in which another building exists between the candidate base station position" in response to the operation of the user.

[0029] When the two-dimensional line-of-sight determination processing unit 5 determines that it has not received the instruction signal (step S4-3, No), the process proceeds to step S5-1. On the other hand, when it determines that it has received the instruction signal (step S4-3, Yes), the process proceeds to step S4-4.

[0030] For each piece of two-dimensional base station candidate position data, the two-dimensional line-of-sight determination processing unit 5 detects, as the building to be detected for the vertical line-of-sight, among the buildings within the design area, the building for which there is another building between the building and the position indicated by the two-dimensional base station candidate position data. For example, the two-dimensional line-of-sight determination processing unit 5 refers to the two-dimensional line-of-sight determination result storage unit 15, and for each piece of two-dimensional base station candidate position data, determines, as the building for which there is another building between the building and the position indicated by the two-dimensional base station candidate position data, the building for which the horizontal line-of-sight range has not been detected, and detects the building as the building to be detected for the vertical line-of-sight (hereinafter, the building to be detected for the vertical line-of-sight is also referred to as the "building to be detected for the line-of-sight").

[0031] For example, in response to an operation by the user of the station placement design support device 1, the two-dimensional line-of-sight determination processing unit 5 takes in, from the outside, data indicating the installation height for each base station candidate position specified by the user and data indicating the height of the building.

[0032] For each building to be detected for the line-of-sight for each detected base station candidate position, the two-dimensional line-of-sight determination processing unit 5 uses the data indicating the height of the building taken in to detect the vertical line-of-sight range from the height of the installation height at the base station candidate position. The two-dimensional line-of-sight determination processing unit 5 associates the building identification data of the building for which the vertical line-of-sight range has been detected with the data indicating the detected vertical line-of-sight range in the building and writes and stores the data in the two-dimensional line-of-sight determination result storage unit 15 (step S4-4). As a result, for each piece of two-dimensional base station candidate position data, the building identification data of the building and the data indicating the horizontal and vertical line-of-sight ranges of the building corresponding to the building identification data are stored in the two-dimensional line-of-sight determination result storage unit 15.

[0033] In the point cloud data processing unit 6, the three-dimensional candidate position selection unit 20 selects a base station candidate position indicating a position that is a candidate for installing a base station in the three-dimensional space and a terminal station candidate position indicating a position that is a candidate for installing a terminal station in the three-dimensional space.

[0034] For example, a user of the placement design support device 1 operates the operation processing unit 10 to select any one of the two-dimensional base station candidate position data from the two-dimensional visibility determination result storage unit 15. The operation processing unit 10 outputs the selected two-dimensional base station candidate position data to the three-dimensional candidate position determination unit 20. The three-dimensional candidate position determination unit 20 takes in the two-dimensional base station candidate position data output by the operation processing unit 10. The three-dimensional candidate position determination unit 20 acquires point cloud data near the position indicated by the taken-in two-dimensional base station candidate position data from the point cloud data storage unit 13, and displays the acquired point cloud data on the screen. The user operates the operation processing unit 10 to select a three-dimensional position that is a candidate for installing a base station from the point cloud data displayed on the screen and outputs it to the three-dimensional candidate position determination unit 20. The three-dimensional candidate position determination unit 20 takes in the three-dimensional position output by the operation processing unit 10, and uses the taken-in three-dimensional position as three-dimensional base station candidate position data.

[0035] Next, the three-dimensional candidate position determination unit 20 reads out data indicating the visibility range of the building associated with the taken-in two-dimensional base station candidate position data from the two-dimensional visibility determination result storage unit 15. The three-dimensional candidate position determination unit 20 reads out point cloud data within the range indicated by the read data indicating the visibility range of the building from the point cloud data storage unit 13, and displays the read point cloud data on the screen. The user operates the operation processing unit 10 to select a three-dimensional position that is a candidate for installing a terminal station from the point cloud data displayed on the screen and outputs it to the three-dimensional candidate position determination unit 20. The three-dimensional candidate position determination unit 20 takes in the three-dimensional position output by the operation processing unit 10, and uses the taken-in three-dimensional position as three-dimensional terminal station candidate position data. Hereinafter, the three-dimensional base station candidate position data is simply referred to as "base station candidate position data", and the three-dimensional terminal station candidate position data is simply referred to as "terminal station candidate position data".

[0036] The three-dimensional line-of-sight determination processing unit 23 reads out the point cloud data of the space between the base station candidate position and the terminal station candidate position indicated by each of the base station candidate position data and the terminal station candidate position data selected by the three-dimensional candidate position selection unit 20 from the point cloud data storage unit 13 (step S5-1). The three-dimensional line-of-sight determination processing unit 23 performs three-dimensional line-of-sight determination processing between the base station candidate position and the terminal station candidate position based on the read point cloud data, and estimates the possibility of communication based on the result of the determination processing (step S5-2).

[0037] On the other hand, when the point cloud data processing unit 6 calculates the shielding rate, the shielding rate calculation unit 24 reads out the point cloud data of the space between the base station candidate position and the terminal station candidate position indicated by each of the base station candidate position data and the terminal station candidate position data selected by the three-dimensional candidate position selection unit 20 from the point cloud data storage unit 13 (step S5-1). The shielding rate calculation unit 24 calculates the shielding rate between the base station candidate position and the terminal station candidate position based on the read point cloud data, and estimates the possibility of communication based on the result of the calculation processing (step S5-2). The point cloud data processing unit 6 including the three-dimensional line-of-sight processing determination unit 23 and the shielding rate calculation unit 24 performs the processing of steps S5-1 to S5-2 for all combinations of the base station candidate position data and the terminal station candidate position data.

[0038] Based on the result of the estimation of the possibility of communication performed by the point cloud data processing unit 6 having either the three-dimensional line-of-sight processing determination unit 23 or the shielding rate calculation unit 24 using the three-dimensional point cloud data, the number of stations calculation unit 7 aggregates the base station candidate positions and the terminal station candidate positions, and calculates the required number of base stations and the number of terminal stations accommodated for each base station candidate position (step S6-1).

[0039] The configuration of the processing in the station placement design support device 1 can also be regarded as a two-stage processing, that is, processing performed using map data, which is two-dimensional data, as shown in FIG. 3, and processing performed using point cloud data, which is three-dimensional data, in response to the result of the processing.

[0040] As shown in FIG. 3, the processes performed using the map data, which is two-dimensional data at the first stage, include four processes: (1) designation of the design area, (2) extraction of candidate positions of the terminal stations, (3) extraction of candidate positions of the base stations, and (4) line-of-sight determination using two-dimensional map data.

[0041] (1) The process of designating the design area corresponds to the processes of steps S1-1 and S1-2 performed by the design area designation unit 2. (2) The process of extracting candidate positions of the terminal stations corresponds to the process of step S2-1 performed by the terminal station candidate position extraction unit 4. (3) The process of extracting candidate positions of the base stations corresponds to the process of step S3-1 performed by the base station candidate position extraction unit 3. (4) The process of line-of-sight determination using two-dimensional map data corresponds to the processes of steps S4-1 to S4-4 performed by the two-dimensional line-of-sight determination processing unit 5.

[0042] The processes performed using the point cloud data, which is three-dimensional data at the second stage, include two processes: (5) determination of communication feasibility using three-dimensional point cloud data, and (6) calculation of the required number of base stations and the number of accommodated terminal stations in the design area.

[0043] (5) The process of determination of communication feasibility using three-dimensional point cloud data corresponds to the processes of steps S5-1 to S5-2 performed by the point cloud data processing unit 6 having the three-dimensional line-of-sight processing determination unit 23 and the shielding rate calculation unit 24. (6) The process of calculation of the required number of base stations and the number of accommodated terminal stations in the design area corresponds to the process of step S6-1 performed by the number calculation unit 7.

[0044] For example, in wireless communication such as millimeter waves, for a base station installed on outdoor facilities such as utility poles and a terminal station installed on the wall surface of a building, three-dimensional visibility determination between the candidate positions of the base station and the candidate positions of the terminal station can be performed using three-dimensional point cloud data to assist in the placement design. To handle three-dimensional point cloud data, a huge amount of data and a large amount of computing resources are required. Therefore, in the placement design support apparatus 1, before using the three-dimensional point cloud data, the two-dimensional visibility determination processing unit 5 determines the two-dimensional visibility between the candidate position of the base station and the candidate position of the terminal station, and using this determination result, the point cloud data processing unit 6 performs three-dimensional visibility determination processing after narrowing down the point cloud data to be used. Therefore, it is possible to perform an efficient three-dimensional visibility determination process with reduced computing resources.

[0045] Also, in wireless communication, it is important not only to perform a simple linear visibility determination but also to calculate the "shielding rate" in the elliptical cylinder-shaped region related to transmission and reception when radio waves propagate in space, that is, in the so-called Fresnel zone. The point cloud data processing unit 6 of the placement design support apparatus 1 calculates the shielding rate by including a shielding rate calculation unit 24. Calculating the shielding rate requires more computing resources than three-dimensional visibility determination processing, but in the placement design support apparatus 1, in the two-dimensional visibility determination process performed by the two-dimensional visibility determination processing unit 5, the point cloud data to be used can be sufficiently narrowed down, so it is possible to perform an efficient shielding rate calculation process with reduced computing resources.

[0046] The wireless communication system for which the placement design support apparatus 1 of the present embodiment targets placement design is a communication system that deploys a base station on outdoor communication facilities (utility poles in the present embodiment) and installs a terminal station on the wall surface of a building to perform wireless communication using millimeter-wave band radio. The placement design support apparatus 1 creates a list of combination patterns of the candidate positions for installing the base station and the candidate positions for installing the terminal station (hereinafter referred to as the "combination pattern list").

[0047] The base station placement design support device 1 performs a process of determining the feasibility of communication between two stations by performing a line-of-sight determination and a shielding rate calculation for the combination patterns of the two stations. The base station placement design support device 1 determines the feasibility of communication between two stations using map information corresponding to a design area (for example, a housing area to be evaluated, etc.) and point cloud data of the design area collected in advance.

[0048] However, as the design area becomes larger, the number of combination patterns of the candidate installation positions of the base station and the candidate installation positions of the terminal station increases, and the computational resources required to determine the feasibility of communication also increase. For example, when calculating the shielding rate between a base station and a terminal station using point cloud data, even if a high-performance PC commercially available at present (as of 2020) is used, it takes about several seconds to calculate the shielding rate for each combination pattern of the two stations.

[0049] If the number of combination patterns of the candidate installation positions of the two stations reaches tens of billions to tens of trillions, it becomes difficult to complete the communication feasibility determination process within a realistic processing time. Therefore, it is necessary to narrow down the number of combination patterns of the candidate installation positions of the two stations to such an extent that the communication feasibility determination process can be completed within a realistic processing time. The number of combination patterns that can complete the communication feasibility determination process within a realistic processing time is, for example, less than 500,000 patterns.

[0050] Before determining the feasibility of communication between the candidate installation positions of the base station and the candidate installation positions of the terminal station within the design area, the base station placement design support device 1 in the present embodiment presents information regarding combination patterns that can complete the communication feasibility determination process within a realistic processing time to the user.

[0051] In the present embodiment, as an example, it is assumed that the number of utility poles included in the design area is about several tens (maximum number: 100 poles), and the number of building blocks is about one hundred to two hundred (maximum number: 200 blocks) for explanation.

[0052] In addition, in this embodiment, it is assumed that the base station is installed on a utility pole and the terminal station is installed on the wall surface of a building. Generally, there are multiple positions on the wall surface of a building where the terminal station can be installed. However, for the sake of simplicity in this embodiment, it is assumed that there is only one position (the centroid point) at the center of the wall surface of the building (facing the base station direction). As a result, the number of candidate installation positions of the base stations existing within the design area corresponds to the number of utility poles (i.e., several tens of poles), and the number of candidate installation positions of the terminal stations existing within the design area is the number of building blocks (i.e., one hundred and several tens of blocks).

[0053] FIG. 4 is a schematic diagram showing the design area in the first embodiment of the present invention. As shown in FIG. 4, in this embodiment, it is assumed that the design area is an area within a circle with a radius D = 200 [m]. This distance of 200 [m] corresponds to a general communication distance of millimeter waves.

[0054] In the design area shown in FIG. 4, the candidate installation positions (utility poles) of the base stations are indicated by the mark "○", and the candidate installation positions (wall surfaces of buildings) of the terminal stations are indicated by the mark "×". Although only a part is shown in FIG. 4, actually, as described above, it is assumed that there are 100 candidate installation positions for the base stations and 200 candidate installation positions for the terminal stations. When installing 100 utility poles in an area with a radius D = 200 [m], it is possible to install the utility poles approximately every 40 - 50 [m], which can be a general installation interval for utility poles.

[0055] In this case, the number of combination patterns between one candidate installation position of a base station within the design area and all candidate installation positions of the terminal stations can be expressed by the following formula (1) by using the binomial theorem.

[0056] n C0 + n C1 + n C2 + ··· + n C k + ··· + n C n-1 + n C n = 2 n ···(1)

[0057] Therefore, the number of combination patterns of the installation candidate positions of all the base stations and the installation candidate positions of all the terminal stations within the design area can be expressed by the following equation (2) by multiplying the value obtained by the above equation (1) by the total number of base stations.

[0058] (Number of combination patterns) = m × 2 n ···(2)

[0059] When the values of m and n in equation (2) are respectively set to 100, the number of installation candidate positions of the base stations (the number of utility poles), and 200, the number of installation candidate positions of the terminal stations (the number of building blocks), the number of combination patterns becomes an extremely large number. Even if the number of installation candidate positions of the base stations and the number of installation candidate positions of the terminal stations are each 1 / 5 of the above numbers (that is, even if m = 20 and n = 40), the number of combination patterns is approximately 22 trillion as shown by the following equation (3).

[0060] (Number of combination patterns) = 20 × 2 40 = 21,990,232,555,520 ···(3)

[0061] Therefore, even so, in order to perform line-of-sight determination and calculate the shielding rate between the two stations, it is still difficult to complete the process within a realistic processing time using general-purpose computing resources such as a PC.

[0062] However, the above equation (1) represents the case where there are no particular constraints on the number of terminal stations that are wirelessly communication-connected to a certain base station. Generally, however, there are constraints on the number of terminal stations that are wirelessly communication-connected to a certain base station based on the direction of the terminal station as seen from the base station that can communicate, or based on the maximum number of frequency channels used by a certain base station, etc. That is, generally, there is an upper limit to the maximum number of terminal stations that can wirelessly communicate with a certain base station.

[0063] Therefore, in the above formula (1), a constraint condition may be provided such that the value of k is equal to or less than its maximum number (for example, the number of frequency channels). As a result, the number of combination patterns of the candidate installation positions of the base stations and the candidate installation positions of the terminal stations can be reduced.

[0064] In the above formula (1), when the number of connections from a certain base station to the terminal stations is k or less, the number of combination patterns of the candidate installation position of a certain base station in the design area and the candidate installation positions of all the terminal stations can be expressed by the following formula (4).

[0065] (Number of combination patterns) = n C1 + n C2 + ··· + n C k = 2 n - ( n C k+1 + ··· + n C n-1 + n C n ) ··· (4)

[0066] Therefore, the number of combination patterns of the candidate installation positions of all the base stations in the design area and the candidate installation positions of all the terminal stations can be expressed by the following formula (5) by multiplying the value obtained by the above formula (4) by the total number of base stations.

[0067] (Number of combination patterns) = m × ( n C1 + n C2 + ··· + n C k ) = m × 2 n - m × ( n C k+1 + ··· + n C n-1 + n C n ) ··· (5)

[0068] In this way, compared with the number of combination patterns obtained by the above formula (2), the number of combination patterns is further reduced by imposing the constraint condition.

[0069] FIG. 5 is a schematic diagram for explaining the reduction of combination patterns by setting constraint conditions. FIG. 5 shows, as an example, a case where the maximum number of terminal stations that one base station can communicate with is 3. On the other hand, FIG. 6 is a schematic diagram for explaining combination patterns when no constraint conditions are set. In the map data (residential map) shown in FIGS. 5 and 6, the positions of utility poles that are candidate positions for installing base stations are indicated by the marks "●" or "○", and the positions at the centers of buildings that are candidate positions for installing terminal stations are indicated by the mark "×". Also, in FIG. 5, the mark "●" represents the position of the utility pole selected as the base station. The mark "○" represents the position of the utility pole not selected as the base station. And the state of wireless communication connection between the base station installed on the utility pole with the "●" mark and the base station installed on the utility pole with the "×" mark is shown by a solid line or a broken line. The solid line indicates the wireless communication connection with the same base stations and terminal stations as those in FIG. 6 described later.

[0070] Compared with the number of base stations in FIG. 5 (49 locations), in FIG. 6, since there are no constraint conditions, a smaller number of base stations (18 locations) can accommodate the terminal stations. However, in FIG. 6, many utility poles where no base stations are deployed are left. Note that when there are no constraint conditions, the accommodation of terminal stations in various selection patterns of base stations different from the selection pattern of the base stations shown in FIG. 6 can be considered. Thus, by imposing a constraint condition on the number of terminal stations connectable to a certain base station, the number of base stations required to accommodate the terminal stations becomes larger. However, in this case, the selection pattern of the base stations is reduced. Therefore, as a result, the number of combination patterns of the candidate positions for installing base stations and the candidate positions for installing terminal stations is reduced from the value of equation (2) to the value of equation (5).

[0071] Hereinafter, the case of performing station placement design by dividing the design area into a plurality of smaller areas (hereinafter referred to as "small areas") will be described. FIG. 7 is a schematic diagram showing an example of performing a station placement design by dividing a design area into small areas. The dashed circle (radius D = 200 [m]) shown in FIG. 7 corresponds to the design area shown in the previous FIG. 4. Here, a case will be described in which the design area shown in FIG. 7 is divided into a plurality of small areas that are circles with a radius d = 50 [m] and a station placement design is performed.

[0072] Similar to FIG. 4, in the design area shown in FIG. 7, the candidate installation positions (utility poles) of the base stations are indicated by the mark "○", and the candidate installation positions (building walls) of the terminal stations are indicated by the mark "×". Although only a part is shown in FIG. 7, actually, as described above, there are 100 candidate installation positions for the base stations and 200 candidate installation positions for the terminal stations.

[0073] As shown in FIG. 7, a circle with a radius d = 50 [m] is used as a small area, and the small areas are arranged side by side without gaps so as to cover the entire design area with a radius D = 200 [m]. In order to arrange them without gaps, it is necessary to arrange adjacent small areas overlapping each other. Therefore, as shown in FIG. 7, 81 small areas with a radius d = 50 [m] are required (= 9×9).

[0074] Also, since the radius of the small area is one-fourth of the radius of the design area, the area of the small area is one-sixteenth of the area of the design area. Therefore, if it is assumed that the candidate installation positions (utility poles) of the base stations and the candidate installation positions (buildings) of the terminal stations in the design area are uniformly distributed, the number of candidate installation positions (utility poles) of the base stations and the number of candidate installation positions (buildings) of the terminal stations existing in one small area are m' = 6.25 (≈100÷16) and n' = 12.5 (≈200÷16), respectively.

[0075] Thus, when applying the above m' = 6.25 and n' = 13 (≈12.5) to the above-mentioned formula (2) for 81 small areas, the number of combination patterns of all candidate installation positions of all base stations and all candidate installation positions of all terminal stations in all small areas can be expressed by the following formula (6).

[0076] (Number of combination patterns) = 81 × 6.25 × 2 13 = 506.25 × 8,192 = 4,147,200 ···(6)

[0077] Approximately 4.15 million combinations, which is the number of combination patterns when performing the placement design by dividing the design area into small areas as shown by formula (6), is less than about 1 / 5.3 million of the approximately 22 trillion combinations, which is the number of combination patterns when performing the placement design without dividing the design area into small areas as shown by the previous formula (3). Thus, by dividing the design area into small areas and performing the placement design, the number of combination patterns can be significantly reduced.

[0078] However, the number of approximately 4.15 million combination patterns does not meet the requirement of being less than 500,000, which is the number of combination patterns that can complete the communication availability determination process within a realistic processing time as an example mentioned above. Therefore, it is conceivable to perform the placement design using even smaller areas with a shorter radius.

[0079] Figures 8 and 9 are schematic diagrams showing an example of performing the placement design by dividing the design area into small areas. Similar to Figure 4, in the design areas shown in Figures 8 and 9, the candidate installation positions (utility poles) of the base stations are indicated by the mark "○", and the candidate installation positions (building walls) of the terminal stations are indicated by the mark "×". Although only a part is shown in Figure 7, actually, as described above, there are 100 candidate installation positions for the base stations and 200 candidate installation positions for the terminal stations.

[0080] The dashed circle (radius D = 200 [m]) shown in Fig. 8 corresponds to the design area shown in Fig. 4 above. Fig. 8 shows the case where the design area is divided into a plurality of small areas that are circles with a radius d = 40 [m] for the station placement design. As shown in Fig. 8, circles with a radius d = 40 [m] are used as small areas, and the small areas are arranged side by side without gaps so as to cover the entire design area with a radius D = 200 [m]. In order to arrange them without gaps, adjacent small areas need to be arranged overlapping each other. Therefore, as shown in Fig. 8, 121 (= 11×11) small areas with a radius d = 40 [m] are required.

[0081] Also, since the radius of the small area is one-fifth of the radius of the design area, the area of the small area is one-twenty-fifth of the area of the design area. Therefore, if it is assumed that the candidate installation positions (utility poles) of the base stations and the candidate installation positions (buildings) of the terminal stations in the design area are uniformly distributed, the number of candidate installation positions (utility poles) of the base stations and the number of candidate installation positions (buildings) of the terminal stations existing in one small area are m” = 4 (= 100÷25) and n” = 8 (= 200÷25), respectively.

[0082] Thus, for the number of small areas: 121 locations, substituting the above m” = 4 and n” = 8 into the aforementioned formula (2), the number of combination patterns of all candidate installation positions of all base stations and all candidate installation positions of all terminal stations in all small areas can be expressed by the following formula (7).

[0083] (Number of combination patterns) = 121×4×2 8 = 484×256 = 123,904 ···(7)

[0084] The approximately 120,000 patterns, which is the number of combination patterns in the case of performing the station placement design by dividing the design area into small areas as shown by formula (7), satisfies less than 500,000 patterns, which is the number of combination patterns that can complete the communication availability determination process in a realistic processing time, cited as an example above.

[0085] However, the smaller the small area is set, the closer the candidate installation positions of the base stations and the candidate installation positions of the terminal stations are. Despite the fact that the combination pattern has good results in line-of-sight determination and calculation of the shielding rate, it is assumed that the number of overlooked cases will increase. Therefore, it is conceivable to adjust the radius of the small area so that the number of combination patterns is closer to 500,000, which is the number of combination patterns that can complete the communication availability determination process within a realistic processing time, as exemplified above.

[0086] The dashed circle (radius D = 200 [m]) shown in FIG. 9 corresponds to the design area shown in FIG. 4 above. FIG. 9 shows a case where the placement design is performed by dividing the design area into a plurality of small areas that are circles with a radius d = 44.4 [m]. As shown in FIG. 9, a circle with a radius d = 44.4 [m] is used as a small area, and the small areas are arranged side by side without gaps so as to cover the entire design area with a radius D = 200 [m]. In order to arrange them without gaps, it is necessary to arrange adjacent small areas overlapping each other. Therefore, as shown in FIG. 8, 100 (= 10 × 10) small areas with a radius d = 44.4 [m] are required.

[0087] Also, since the radius of the small area is about two-ninths of the radius of the design area, the area of the small area is about four eighty-firsts of the area of the design area. Therefore, if it is assumed that the candidate installation positions (utility poles) of the base stations and the candidate installation positions (buildings) of the terminal stations in the design area are uniformly distributed, the number of candidate installation positions (utility poles) of the base stations and the number of candidate installation positions (buildings) of the terminal stations existing in one small area are m''' = 4.94 (≈ 100 ÷ 81 × 4) and n''' = 10 (≈ 200 ÷ 81 × 4), respectively.

[0088] Thus, when applying the above m''' = 4.94 and n''' = 10 to the aforementioned formula (2) for 100 small areas, the number of combination patterns of all candidate installation positions of all base stations and all candidate installation positions of all terminal stations in all small areas can be expressed by the following formula (8).

[0089] (Number of combination patterns) = 100 × 4.94 × 2 10 = 494 × 1024 = 505,856 ···(8)

[0090] Approximately 500,000 patterns, which is the number of combination patterns in the case of performing the placement design by dividing the design area into small areas as shown by the formula (8), corresponds to the upper limit of 500,000 patterns of the number of combination patterns that can complete the communication availability determination process in a realistic processing time, which was given as an example above. Thus, by adjusting the radius of the small area, it is possible to perform a more effective placement design within a realistic calculation processing time.

[0091] Here, as shown in FIGS. 7 to 9, since a plurality of small areas are arranged so as to overlap, the same combination pattern may be counted repeatedly in the combination patterns calculated by the formulas (6), (7), and (8). By appropriately deleting this repeated count, the combination pattern is further reduced.

[0092] Hereinafter, an example of the operation in creating the combination pattern list of the placement design support device 1 will be described. FIG. 10 is a flowchart showing the operation of creating the combination pattern list of the placement design support device 1 in the first embodiment of the present invention.

[0093] The area division unit 171 sets the size of a small area (for example, a circle with a radius of 50 [m]) that is smaller than the design area (for example, a circle with a radius of 200 [m]) (step S101). The area division unit 171 sets the positions of the small areas so as to fill the design area with a plurality of small areas (step S102). Here, it should be noted that adjacent small areas are set so as to overlap each other and have sufficient overlap. The combination pattern extraction unit 172 generates a combination pattern list, which is a list of combination patterns of candidate installation positions (utility poles) of base stations and candidate installation positions (buildings) of terminal stations, for each small area (step S103). The combination pattern extraction unit 172 records the generated combination pattern list in the combination pattern list storage unit 18.

[0094] The combination pattern extraction unit 172 determines whether the generation of the combination pattern list has been completed for all the small areas (step S104). If there is a small area for which the combination pattern list has not been generated (step S104·NO), the duplicate pattern deletion unit 173 detects duplicate combination patterns among the combination pattern lists generated for each small area. The duplicate pattern deletion unit 173 leaves only one of the duplicate combination patterns and deletes the others (step S105). Then, it returns to step S103.

[0095] On the other hand, if the generation of the combination pattern list has been completed for all the small areas (step S104·YES), it is determined whether there are duplicate combination patterns in the already generated combination pattern list (step S106). If there are duplicate combination patterns in the already generated combination pattern list (step S106·YES), the duplicate pattern deletion unit 173 leaves only one of the duplicate combination patterns and deletes the others (step S107). Then, it returns to step S106.

[0096] If there is no duplicate combination pattern in the already generated combination pattern list (step S106·NO), the base station design support device 1 outputs the generated combination pattern list. For example, the base station design support device 1 presents it to the user by causing the generated combination pattern list to be displayed on a display unit (not shown). With the above, the operation of the base station design support device 1 shown in the flowchart of FIG. 10 ends.

[0097] As described above, according to the base station design support device 1 in the first embodiment, when there are, for example, about a hundred installation candidate positions for base stations and about a hundred to several hundred installation candidate positions for terminal stations in the design area, it is possible to present an appropriate combination pattern. If all combination patterns of all installation candidate positions of all base stations and all installation candidate positions of all terminal stations in such a design area are to be evaluated, as described above, the number of combination patterns becomes a number on the order of dozens of trillions. Therefore, in this case, it becomes difficult to perform a visibility determination and a calculation of a shielding rate for each combination pattern within a realistic calculation time.

[0098] According to the base station design support device 1 in the first embodiment, the design area is divided into a plurality of small areas, and a combination pattern list is created for each small area, so that the number of combination patterns can be significantly reduced. As a result, the base station design support device 1 can reduce the number of combination patterns to such an extent that a visibility determination and a calculation of a shielding rate can be performed within a realistic calculation time (for example, less than 5 million patterns).

[0099] Furthermore, the base station design support device 1 in the first embodiment arranges a plurality of small areas so as to cover the entire design area while allowing overlap. Thereby, the base station design support device 1 can reduce the possibility of overlooking a combination pattern having a positional relationship across the boundary of adjacent small areas and having good results in visibility determination and shielding rate calculation. From the above, the base station design support device 1 in the present embodiment can perform a more effective base station design within a realistic calculation processing time.

[0100] (Modification of the First Embodiment) In the above-described first embodiment, the co-location design support apparatus 1 is configured to set small areas so as to cover the design area while allowing overlap by a plurality of circular small areas. However, the configuration is not limited to this, and the shape of the small area may not be circular.

[0101] For example, FIG. 11 is a schematic diagram showing a case where the co-location design support apparatus 1 uses a plurality of rectangular (square) small areas. For example, as shown in FIG. 11, the small areas may be arranged while being shifted vertically and horizontally with half the length of one side of the square (50 [m] in FIG. 11) as a unit, and the design area may be covered with a plurality of small areas while allowing overlap.

[0102] Further, for example, FIG. 12 is a schematic diagram showing a case where the co-location design support apparatus 1 uses a plurality of hexagonal (regular hexagon) small areas. For example, as shown in FIG. 12, the small areas may be arranged while being shifted vertically and horizontally with the length of one side of the regular hexagon (50 [m] in FIG. 12) as a unit, and the design area may be covered with a plurality of small areas while allowing overlap.

[0103] (Second Embodiment) In the above-described first embodiment, the case where the co-location design support apparatus 1 is arranged so as to align a plurality of small areas of the same shape at equal intervals with respect to the design area has been described. However, Generally, utility poles that are candidate installation positions for base stations are often built along the sides of roads, and the wall surfaces of buildings that are candidate installation positions for terminals often face the roads.

[0104] Therefore, it is considered that there is often a line of sight and a low shielding rate between the wall surface of a building facing the same road section as the road section where the utility pole is built. On the other hand, it is considered that there is often no line of sight and a high shielding rate between the wall surface of a building facing a road section different from the road section where the utility pole is built. Note that the road section mentioned here refers to a section of a road where there is a clear view (without turning).

[0105] In the placement design support device 1 according to the second embodiment described below, it is possible to exclude in advance a combination pattern of a candidate installation position (utility pole) of a base station and a candidate installation position (building) of a terminal station, which are assumed to be in different road sections and have no clear view and a high shielding rate. By setting such a constraint condition, the placement design support device 1 can reduce the number of combination patterns.

[0106] The placement design support device 1 in the present embodiment sets a plurality of small areas that fill the design area by using information such as roads included in the map data. FIG. 13 is a schematic diagram showing a case where the placement design support device 1 uses a plurality of small areas based on road sections.

[0107] As described in the first embodiment above, if a visibility determination and a shielding rate calculation process are performed for all combination patterns of all candidate base station installation positions (i.e., utility poles) and all candidate terminal station installation positions (i.e., building walls) existing in the design area, an enormous amount of calculation is required. Therefore, it is necessary to reduce the number of combination patterns to a number that can be processed within a realistic calculation processing time.

[0108] Similar to FIGS. 7 to 9 and the like shown in the first embodiment above, in the second embodiment, as an example, an area of 400 [m] square is considered as the design area. Similar to the first embodiment, in FIG. 13, the candidate installation position (utility pole) of the base station is indicated by the mark "○", and the candidate installation position (building wall) of the terminal station is indicated by the mark "×".

[0109] If the housing area shown in FIG. 13 is taken as the design area, the number of combination patterns of the installation candidate positions (utility poles) of all base stations and the installation candidate positions (buildings) of all terminal stations existing within this design area is the value obtained by the following equation (9) (about 1 trillion patterns). Thus, the number of combination patterns exceeds the number of combination patterns (for example, 500,000 patterns) that can complete the communication availability determination process within a realistic processing time.

[0110] (Number of combination patterns) = 16 × 2 36 = 16 × 68,719,476,736 = 1,099,511,627,776 ···(9)

[0111] Note that the above equation (9) is obtained by substituting m = 16 and n = 36, which are the number of installation candidate positions (utility poles) of the base stations and the number of installation candidate positions (buildings) of the terminal stations shown in FIG. 13, into the aforementioned equation (2).

[0112] The station placement design support device 1 in the present embodiment sets small areas for each road section using map data. The station placement design support device 1 generates a list of combination patterns of the installation candidate positions (for example, utility poles) of base stations and the installation candidate positions (for example, building walls) of terminal stations for each set small area.

[0113] Note that the station placement design support device 1 sets the road sections by dividing the road so that, for example, in a curved road, a section with a view is taken as one road section. Also, for example, in the case of a long straight road with a view far away, the road is divided so that, for example, a section of 200 [m] is taken as one road section. This distance of 200 [m] is the upper limit distance at which wireless communication can be sufficiently performed using millimeter-wave radio waves.

[0114] As shown in FIG. 13, for example, the placement design support device 1 divides the roads in the design area into eight road sections: road section A, road section B, road section C, …, road section G, and road section H. The placement design support device 1 sets a small area for each of these eight road sections. In FIG. 13, the small areas are shown as solid-line ellipses. The placement design support device 1 arranges the eight small areas while allowing overlap so that the entire design area is filled.

[0115] For example, in the housing area (design area) shown in FIG. 13, in the small area including road section A, there are three utility poles which are candidate positions for installing a base station, and eight buildings which are candidate positions for installing a terminal station. By applying these numbers (m = 3, n = 8) to the above-mentioned formula (2), the number of combination patterns in the small area including road section A is 768 according to the following formula (10).

[0116] (Number of combination patterns) = 3 × 2 8 = 3 × 256 = 768 ···(10)

[0117] The 768 combination patterns of the small area including road section A shown by formula (10) in this way are approximately less than 1 / 1400000000 of the approximately 1 trillion combination patterns when performing placement design without dividing the design area into small areas, which is shown by the previous formula (9).

[0118] Similarly, for example, in the housing area (design area) shown in FIG. 13, in the small area including road section B, there are four utility poles which are candidate positions for installing a base station, and seven buildings which are candidate positions for installing a terminal station. By applying these numbers (m = 4, n = 7) to the above-mentioned formula (2), the number of combination patterns in the small area including road section B is 512 according to the following formula (11).

[0119] (Number of combination patterns) = 4 × 2 7 = 4 × 128 =512 ···(11)

[0120] The 512 combinations of small areas including road section B, as shown by equation (11), are less than approximately 1 / 2.1 billion of the approximately 1 trillion combinations in the case of performing base station placement design without dividing the design area into small areas, as shown by the previous equation (9).

[0121] Similarly, for example, in the residential area (design area) shown in FIG. 13, there are 3 utility poles, which are candidate positions for installing base stations, and 7 buildings, which are candidate positions for installing terminal stations, in the small area including road section H. By applying these numbers (m = 3, n = 7) to the aforementioned equation (2), the number of combination patterns in the small area including road section H is 192 according to the following equation (12).

[0122] (Number of combination patterns)=3×2 6 =3×128 =384 ···(12)

[0123] The 384 combinations of small areas including road section H, as shown by equation (12), are less than approximately 1 / 2.9 billion of the approximately 1 trillion combinations in the case of performing base station placement design without dividing the design area into small areas, as shown by the previous equation (9).

[0124] In this way, the number of combination patterns in the 8 small areas from the small area including road section A to the small area including road section H can be calculated respectively as described above. The sum of the number of combination patterns of these 8 small areas is at least less than approximately 1 / 1 billion of the approximately 1 trillion combinations in the case of performing base station placement design without dividing the design area into small areas, as shown by the previous equation (9). In this way, by dividing the design area into small areas based on road sections and performing base station placement design, the number of combination patterns can be significantly reduced.

[0125] Hereinafter, an example of the operation in creating the combination pattern list of the station layout design support device 1 will be described. FIG. 14 is a flowchart showing the operation of creating the combination pattern list of the station layout design support device 1 in the second embodiment of the present invention.

[0126] The area division unit 171 divides the roads included in the design area into a plurality of road sections based on the map data (step S201). For example, the area division unit 171 divides the road every straight line within a communicable distance. Note that, for example, the area division unit 171 divides the curved section every line of sight. However, as a point of attention, the division of the road sections allows the boundaries of adjacent road sections to overlap each other so that adjacent road sections overlap.

[0127] The area division unit 171 groups utility poles and buildings for each small area including each road section based on the map data and the facility data (step S202). In the following description, a small area including a certain road section may be simply referred to as a "road section". The area division unit 171 determines whether or not grouping has been performed for all the road sections within the design area (step S203).

[0128] If there is a road section in the design area for which grouping has not been performed (step S203·NO), the combination pattern extraction unit 172 extracts the combination pattern of the utility pole (installation candidate position of the base station) and the building (installation candidate position of the terminal station) for each group (step S204). The combination pattern extraction unit 172 generates a combination pattern list that is a list of the extracted combination patterns (step S205). The combination pattern extraction unit 172 records the generated combination pattern list in the combination pattern list storage unit 18.

[0129] The duplicate pattern deletion unit 173 determines whether there are identical (duplicate) combination patterns among the combination pattern lists of different small areas (step S206). That is, in this determination, it checks for the presence of duplicate combination patterns in which base stations and terminal stations are installed at the same utility pole and the same building in different groups, respectively.

[0130] If there is an identical (duplicate) combination pattern among the combination pattern lists of different small areas (step S206·YES), the duplicate pattern deletion unit 173 leaves only one of the duplicate combination patterns and deletes the others (step S207). Then, it returns to step S206.

[0131] On the other hand, if there is no identical (duplicate) combination pattern among the combination pattern lists of different small areas (step S206·NO), it returns to step S203, and the area division unit 171 determines whether all road sections in the design area have been grouped. If all road sections in the design area have been grouped (step S203·YES), the station placement design support device 1 outputs the generated combination pattern list. For example, the station placement design support device 1 presents it to the user by displaying the generated combination pattern list on a display unit (not shown) (step S208). Thus, the operation of the station placement design support device 1 shown in the flowchart of FIG. 14 ends.

[0132] As described above, according to the station placement design support device 1 in the second embodiment, when there are installation candidate positions of a plurality of base stations and installation candidate positions of a plurality of terminal stations in the design area, it is possible to present an appropriate combination pattern. If all combination patterns of all installation candidate positions of all base stations and all installation candidate positions of all terminal stations in such a design area are to be evaluated, as described above, the number of combination patterns is, for example, a number exceeding 1 trillion. Therefore, in this case, it becomes difficult to perform a perspective determination and a calculation of the shielding rate for each combination pattern within a realistic calculation time.

[0133] In the second embodiment, the base station placement design support device 1 divides the roads included in the design area into a plurality of road sections based on the map data, and sets a small area for each road section. Since the base station placement design support device 1 creates a combination pattern list for each small area, the number of combination patterns can be significantly reduced. As a result, the base station placement design support device 1 can reduce the number of combination patterns to such an extent that it is possible to perform line-of-sight determination and calculation of the shielding rate within a realistic calculation time (for example, less than 500,000 cases).

[0134] Further, since the base station placement design support device 1 in the second embodiment sets a small area for each road section, it is possible to generate a combination pattern list so as to exclude combination patterns in which the results of line-of-sight determination and calculation of the shielding rate between the candidate installation positions of the base stations and the candidate installation positions of the terminals are unlikely to be good. This is because, as described above, it is considered that there is no line of sight and the shielding rate is often high between the wall surfaces of buildings facing road sections different from the road sections where utility poles are erected.

[0135] Furthermore, in the second embodiment, the base station placement design support device 1 arranges a plurality of small areas so as to cover the entire design area while allowing overlap. As a result, the base station placement design support device 1 can reduce the possibility of overlooking combination patterns in which the positional relationship straddles the boundaries of adjacent small areas and the results of line-of-sight determination and calculation of the shielding rate are good.

[0136] (Third Embodiment) In the third embodiment, the base station placement design support device 1 is configured to present to the user the recommended base station installation position (hereinafter referred to as the "recommended installation position") based on the design area specified by the user and the installation position of the terminal station. When a plurality of terminal stations are specified, depending on the positions where the terminal stations are specified, the number of combination patterns for performing line-of-sight determination and calculation processing of the shielding rate may become enormous (for example, tens of billions of cases). The base station placement design support device 1 in the present embodiment can reduce such combination patterns.

[0137] Next, an example of the operation of the co-location design support device 1 in the third embodiment will be described. FIG. 15 is a flowchart showing the operation of the co-location design support device 1 in the third embodiment of the present invention.

[0138] First, the design area specifying unit 2 specifies a design area based on a designation input by the user (step S301). The design area to be specified is, for example, a specific area in the map data stored in the map data storage unit 11 as shown on the left side of FIG. 16.

[0139] Next, the base station candidate position extraction unit 3 acquires facility data from the facility data storage unit 12 and extracts information on outdoor communication facilities including utility poles within the design area (step S302). The information extracted here is, for example, the information as shown on the right side of FIG. 16. As shown on the right side of FIG. 16, the information includes, for example, the utility pole number for identifying the utility pole, the position and type of the utility pole, etc. within the designated design area.

[0140] Based on the information on outdoor communication facilities including utility poles, the point cloud data processing unit 6 causes, for example, as shown in FIG. 17, candidate positions (utility poles) of the base station based on the information extracted in step S302 to be displayed on the map of the designated design area on, for example, a display unit (not shown). In the map shown in FIG. 17, the number of utility poles is 94, and the number of building blocks is 230. The utility poles are represented by "〇" marks.

[0141] The point cloud data processing unit 6 designates the installation position of the terminal station based on the specified input by the user (step S303). For example, in the map shown in FIG. 18, the installation position of the terminal station is represented by a "×" mark. The point cloud data processing unit 6 extracts the installation candidate positions (utility poles) of the base stations that are determined to have a clear line of sight or have a shielding rate less than a predetermined value, centered on the designated terminal station, based on the designated installation position of the terminal station (step S304). In the map shown in FIG. 19, the five extracted installation candidate positions (utility poles) of the base stations are indicated by "○" marks. Also, symbols ("A", "B", "C", "D", ···) for identifying the installation candidate positions of each base station are shown.

[0142] The recommended pattern specifying unit 174 presents the recommended installation positions of the base stations to the user (step S305). Thus, the operation of the station placement design support device 1 shown in the flowchart of FIG. 15 ends.

[0143] Next, two presentation methods for the recommended installation positions of the base stations will be described. The first presentation method is to derive the recommended installation positions of the base stations for accommodating the terminal stations with the minimum number of base stations. In this first presentation method, it is assumed that the user of the station placement design support device 1 designates the installation positions of a plurality of terminal stations.

[0144] FIG. 20 is a diagram showing an example of a list presented by the station placement design support device 1 in the third embodiment of the present invention. As shown in FIG. 20, in the first presentation method, in the design area, the recommended installation positions of the base stations are presented such that the number of terminal stations determined to have no clear line of sight to any of the installation candidate positions of the base stations is minimized and the number of base stations required to accommodate the terminal stations within the design area is minimized.

[0145] In the list shown in FIG. 20, the minimum number of terminal stations determined to have no line of sight to any of the candidate installation positions of the base stations is 16. Among these, the minimum number of base stations required to accommodate the terminal stations within the design area is 2. In this case, there are two combinations of the two base stations required to accommodate the terminal stations within the design area, namely, "A" and "D", or "B" and "D". Therefore, the first-ranked evaluation order is assigned to these two combinations of base stations.

[0146] The second presentation method derives the recommended installation positions of the base stations so as to minimize the number of terminal stations that cannot be connected to a plurality of base stations. In other words, the second presentation method presents the recommended installation positions of the base stations such that each of the plurality of terminal stations specified by the user can be connected to as many base stations as possible.

[0147] FIG. 21 is a diagram showing an example of a list presented by the station placement design support apparatus 1 according to the third embodiment of the present invention. As shown in FIG. 21, in the second presentation method, in the design area, after minimizing the number of terminal stations determined to have no line of sight to any of the candidate installation positions of the base stations, and further after minimizing the number of terminal stations that cannot be connected to a plurality of base stations, the recommended installation positions of the base stations are presented such that the number of base stations required to accommodate the terminal stations within the design area is minimized.

[0148] In the list shown in FIG. 21, the minimum number of terminal stations determined to have no line of sight to any of the candidate installation positions of the base stations is 16. Among these, the minimum number of terminal stations that cannot be connected to a plurality of base stations is 1. Further, among these, the minimum number of base stations required to accommodate the terminal stations within the design area is 4. In this case, there is only one combination of the four base stations required to accommodate the terminal stations within the design area, namely, "A", "B", "C", and "D". Therefore, the first-ranked evaluation order is assigned to this one combination of base stations.

[0149] To derive the recommended installation positions of the base stations, the number of utility poles that are candidate installation positions for the base stations in the design area and the number of terminal stations (specified by the user) are important. If these numbers are too large, the number of combination patterns of the candidate installation positions of the base stations and the installation positions of the terminal stations will become an enormous number that makes it impossible to perform the determination of the line of sight and the calculation of the shielding rate within a realistic time.

[0150] The following will be described with reference to FIG. 22. Hereinafter, let the number m of candidate installation positions (utility poles) of the base stations in the design area be 100, and let the number n of installation positions of the terminal stations specified by the user be 5. The terminal stations installed at these five locations may be communicatively connected to, for example, 33 base stations. Note that the value of 33 is an estimated value based on the assumption that the terminal stations can be communicatively connected to about one-third of these base stations, even if underestimated, since there are 100 candidate installation positions of the base stations in the design area.

[0151] In actuality, when five terminal stations are specified, due to the differences in the positions of each of the five terminal stations and the positions of a plurality of base stations existing around each of these terminal stations, the same number of base stations are not necessarily selected for each terminal station (that is, the same number of combination patterns are not necessarily generated). However, here, for the sake of simplicity of explanation, the number of combination patterns will be roughly estimated, and it is assumed that the same number of base stations are selected for each terminal station.

[0152] The number m = 33 of the base stations and the number n = 5 of the terminal stations are sufficiently assumable numerical values as described above if the wireless communication distance between the two stations is about 200 [m]. Using these numbers (m = 33, n = 5), when calculating the number of combination patterns following the aforementioned formula (2), it becomes about 43 billion patterns according to the following formula (13). Note that in the following formula (13), the positions of the number m of the base stations and the number n of the terminal stations are reversed from those in formula (2).

[0153] (Number of combination patterns) = n × 2 m = 5 × 233 =5 × 8,589,934,592 =42,949,672,960 ···(13)

[0154] Thus, even assuming that the candidate installation positions of the base stations with respect to the terminal stations are estimated to be as few as one-third of the 100 utility poles in the design area, i.e., 33 locations, the number of combination patterns between the base stations and the terminal stations would be approximately 43 billion. If it is assumed that, for example, it takes 3 seconds to calculate the shielding rate for each combination pattern, then 35.833 million hours (= 129 billion seconds) would be required to process all the combination patterns. This corresponds to 1.493 million days, that is, a period exceeding 4000 years.

[0155] In the first embodiment described above, for example, a small area (a circular area with a radius of 44.4 [m]) was set with respect to the design area (a circular area with a radius of 200 [m] in a 400 [m] square area). As a result, in the above calculation, the number of combination patterns could be reduced from approximately 22 trillion to approximately 500,000.

[0156] However, in reality, it is not always possible to perform the prospective determination of 500,000 combination patterns and the calculation of the shielding rate with the available computing resources (because it is also assumed that in some cases, only fewer computing resources can be prepared). Therefore, a method of adjusting the radius of the small area to be shorter will be described below in order to further reduce the number of combination patterns according to the available computing resources.

[0157] FIG. 23 is a diagram showing the adjustment of the radius of the small area. FIG. 23 is a diagram for explaining a method of reducing the number of combination patterns (about 43 billion patterns) calculated by the above formula (13). Here, the circular study range set under the assumption that the wireless communication distance between the terminal station and the base station is about 200 [m], as shown in FIG. 22 described above, is adjusted. Specifically, for example, the diameter D of the circle centered on the position of the terminal station designated by the user, as shown in FIG. 23 Z is represented by the following formula (14).

[0158] D Z = 200 - 50 × i ···(14)

[0159] Here, when i = 0, it corresponds to the circular area shown in FIG. 22 (the same as the two-dot chain line circular area shown in FIG. 23), and the radius Dz = 200 [m]. In this area, as described above, the number of combination patterns is about 43 billion patterns. Therefore, the number of combination patterns is adjusted to be 500,000 patterns or less that can be processed in a realistic time.

[0160] The station placement design support device 1 increases the value of i step by step. As a result, step by step, the radius of the small area becomes shorter and the number of combination patterns decreases. In the above formula (14), if i = 1 as the first step, the radius Dz of the circle becomes 150 [m]. That is, in FIG. 23, it shrinks from the two-dot chain line circular area to the one-dot chain line circular area. In this first step, it is assumed that the number of installation candidate positions of the base station capable of wireless communication with the terminal station is m = 25. Also, assume that the number of designated terminal stations remains unchanged at n = 5. Based on these conditions of n = 5 and m = 25, the number of combination patterns is represented by the following formula (15).

[0161] (Number of combination patterns) = n × 2 m = 5 × 2 25 = 5 × 33,554,432 = 167,772,160 ···(15)

[0162] Thus, the number of combination patterns in the case of i = 1 is approximately 170 million, which is not a practically processable number of combination patterns. If the time required to process one set of combination patterns is 3 [seconds], the time required to process all (170 million) combination patterns is 503.31 million [seconds], that is, it takes about 16 years. This only reduces the approximately 43 billion combination patterns calculated by the above formula (13) to 1 / 256.

[0163] In the above formula (14), if i = 2 is set as the second stage, the radius Dz of the circle becomes 100 [m]. That is, in FIG. 23, it shrinks from the circular area of the dashed-dotted line to the circular area of the solid line. In this second stage, it is assumed that there are m = 16 candidate installation positions for the base stations that can communicate wirelessly with the terminal stations. Also, the number of specified terminal stations remains unchanged, and it is assumed that n = 5. Based on these conditions of n = 5 and m = 16, the number of combination patterns is represented by the following formula (16).

[0164] (Number of combination patterns) = n × 2 m = 5 × 2 16 = 5 × 65,536 = 327,680 ··· (15)

[0165] Thus, the number of combination patterns in the case of i = 2 is approximately 330,000, which is a practically processable number of combination patterns. This reduces the approximately 43 billion combination patterns calculated by the above formula (13) to 1 / 130,000. Thus, according to this embodiment, the number of combination patterns can be gradually reduced and adjusted so as to satisfy less than 500,000, which is a practically processable number of combination patterns within a predetermined calculation time.

[0166] FIG. 24 is a flowchart showing the operation of the station placement design support device 1 in the third embodiment of the present invention. First, the design area specifying unit 2 specifies a design area based on a specified input by the user (step S401). Next, the point cloud data processing unit 6 specifies the positions of the terminal stations based on a specified input by the user (step S402). Here, it is also possible to specify a plurality of terminal stations.

[0167] Next, the point cloud data processing unit 6 selects a base station located within a wireless communication range from the terminal stations (step S403). The combination pattern extraction unit 172 calculates the number of combination patterns from the (plurality of) terminal stations and the base station selected in step S403 (step S404). The combination pattern extraction unit 172 determines whether the calculated number of combination patterns is equal to or less than a predetermined value (for example, 500,000 patterns) (step S405).

[0168] If the number of combination patterns exceeds the predetermined value (step S405·NO), the combination pattern extraction unit 172 determines whether it is possible to shorten the distance from the terminal station that selects the base station (step S406). If it is possible to shorten the distance from the terminal station that selects the base station (step S406·YES), the combination pattern extraction unit 172 selects a base station at a shorter distance from the terminal station (step S407). Then, it returns to step S404.

[0169] On the other hand, if it is not possible to shorten the distance from the terminal station that selects the base station (step S406·NO), the combination pattern extraction unit 172 deletes the specification of some of the specified plurality of terminal stations (step S408). Then, it returns to step S403.

[0170] Although not shown in the flowchart of FIG. 24, it is assumed that in step S408, it may not be possible to simply delete some of the specified plurality of terminal stations. That is, there may be a case where, even with one terminal station and the shortest possible distance, the predetermined number of combination patterns is exceeded. In such a case, it is conceivable that the station placement design support apparatus 1 separately presents it to the user.

[0171] On the one hand, in step S405 above, when the number of combination patterns is less than or equal to a predetermined value (step S405·YES), for each combination pattern included in the generated combination pattern list, the point cloud data processing unit 6 performs a line-of-sight determination process using the point cloud data or a shielding rate calculation process respectively (step S409). Thus, the operation of the station location design support device 1 shown in the flowchart of FIG. 24 ends.

[0172] As described above, according to the station location design support device 1 in the third embodiment, when there are a plurality of utility poles that are candidate installation positions of the base station within the design area and the position of at least one terminal station is specified on the wall surface of an arbitrary building, etc., it is possible to present an appropriate combination pattern. If all candidate installation positions of the base stations located within the wireless communication range from the terminal station in such a design area are selected, the number of combination patterns will be on the order of tens of billions. Therefore, in this case, it becomes difficult to perform line-of-sight determination and shielding rate calculation for each combination pattern within a realistic calculation time.

[0173] The station location design support device 1 in the third embodiment gradually shortens the radius of the circular area indicating the distance from the installation position of the terminal station to the candidate installation position of the base station to be selected. Thereby, the station location design support device 1 can gradually reduce the number of combination patterns. Thereby, the station location design support device 1 can be adjusted step by step so as to reduce the number of combination patterns to a level where line-of-sight determination and shielding rate calculation can be performed within a realistic calculation time (for example, less than 500,000 patterns).

[0174] (Modification Example of the Third Embodiment) In the foregoing third embodiment, the base station placement design support device 1 was configured to reduce the number of combination patterns by gradually shortening the radius of the circular area indicating the distance to the candidate installation positions of the base stations to be selected. On the other hand, in a modification of the third embodiment, the base station placement design support device 1 adjusts the radius of the circular area indicating the distance to the candidate installation positions of the base stations to be selected to gradually increase so that the number of combination patterns approaches a desired value.

[0175] FIG. 25 is a diagram showing the adjustment of the radius of the small area. Specifically, for example, the base station placement design support device 1 gradually increases the radius of the area. As a result, the number of combination patterns gradually increases. At a certain stage, if the number of combination patterns exceeds the upper limit that can be processed within a realistic calculation time, the base station placement design support device 1 determines the number of combination patterns calculated at the previous stage as the optimal number of patterns. Then, the base station placement design support device 1 performs processes such as line-of-sight determination and calculation of the shielding rate for each combination pattern included in the combination pattern list generated at the previous stage.

[0176] Thus, the base station placement design support device 1 in the modification of the third embodiment adjusts to obtain the optimal number of combination patterns by increasing the length in order from the shortest communication distance, contrary to reducing the number of combination patterns by gradually shortening the communication distance as in the base station placement design support device 1 in the foregoing third embodiment. By adopting a configuration in which the target area is gradually expanded from the shortest communication distance, the base station placement design support device 1 in the modification of the third embodiment can perform base station placement design with fewer computing resources compared to the foregoing third embodiment.

[0177] The reason for this is that the smaller the target area, the fewer the number of combination patterns. The placement design support device 1 in the modified example of the third embodiment starts with a smaller number of combination patterns and gradually increases the number of combination patterns as needed to obtain the optimal number of combination patterns. Therefore, the placement design support device 1 in the modified example of the third embodiment can significantly reduce the computational resources compared to the above-described third embodiment, which obtains the optimal pattern number by gradually decreasing the number of combination patterns from a large number of combination patterns at the first stage as needed.

[0178] The placement design support device 1 in the above-described embodiment includes an area division unit 171 that divides a designated design area into a plurality of small areas that are smaller than the designated area and at least partially overlap, a combination pattern extraction unit 172 that extracts, for each small area, a combination pattern of installation candidate positions of base stations (first radio stations) and installation candidate positions of terminal stations (second radio stations) included in the small area and generates a combination pattern list, a duplicate pattern deletion unit 173 that deletes duplicate combination patterns among the combination pattern lists for each small area, and an output unit that outputs the combination pattern list from which the duplicate combination patterns have been deleted.

[0179] By having the above configuration, the placement design support device 1 can make it difficult for a combination pattern of an installation candidate position of a base station and an installation candidate position of a terminal station that exists across the boundary between two adjacent small areas to be excluded from evaluation while significantly reducing the combination patterns. Thereby, the placement design support device 1 can support performing a more effective placement design within a realistic calculation processing time.

[0180] In the above first to third embodiments, millimeter-wave wireless is shown as an example of the wireless communication performed between the base station and the terminal station, but it may be terrestrial digital communication other than millimeter-wave wireless communication, communication by satellite radio waves, or communication using UHF (Ultra High Frequency).

[0181] The placement design support device 1 in each of the above-described embodiments may be implemented by a computer. In that case, a program for realizing this function may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be read into a computer system and executed to realize it. Here, the "computer system" shall include hardware such as an OS and peripheral devices. Further, the "computer-readable recording medium" refers to a portable medium such as a flexible disk, a magneto-optical disk, a ROM, a CD-ROM, etc., and a storage device such as a hard disk built into a computer system. Furthermore, the "computer-readable recording medium" also includes those that dynamically hold a program for a short time, such as a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line, and those that hold a program for a certain period of time, such as a volatile memory inside a computer system serving as a server or a client in that case. Also, the above program may be for realizing a part of the aforementioned functions, and may further be realizable in combination with a program already recorded in a computer system for realizing the aforementioned functions, and may also be realized using a programmable logic device such as an FPGA (Field Programmable Gate Array).

[0182] As described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and designs and the like within the scope not departing from the gist of the present invention are also included.

Industrial Applicability

[0183] Utilizing point cloud data, it can be applied to line-of-sight determination and calculation of shielding rate from a base station placed on outdoor equipment such as a utility pole to a terminal station installed on the wall surface of a building in the placement design for determining the locations to install wireless base stations and terminal stations.

Explanation of Reference Numerals

[0184] 1... Layout design support device, 2... Design area specifying unit, 3... Base station candidate position extraction unit, 4... Terminal station candidate position extraction unit, 5... Two-dimensional line-of-sight determination processing unit, 6... Point cloud data processing unit, 7... Number of stations calculation unit, 10... Operation processing unit, 11... Map data storage unit, 12... Facility data storage unit, 13... Point cloud data storage unit, 15... Two-dimensional line-of-sight determination result storage unit, 17... Pattern number control unit, 18... Combination pattern list storage unit, 20... Three-dimensional candidate position selection unit, 23... Three-dimensional line-of-sight determination processing unit, 24... Shielding rate calculation unit, 171... Area division unit, 172... Pattern extraction unit, 173... Duplicate pattern deletion unit, 174... Recommended pattern identification unit, 800, 801... Buildings, 810, 811, 812... Houses, 821, 826... Utility poles, 830, 834... Base stations, 840, 844... Terminal stations, 850, 851... Station buildings, 900, 901... Optical fibers

Claims

1. obtaining information indicative of a location of at least one first wireless station; calculating a number of combination patterns of at least one first wireless station and at least one candidate installation location of a second wireless station located within a predetermined distance from a location of the first wireless station; If the number of the combination patterns exceeds a predetermined number, gradually shortening the predetermined distance; outputting the number of combination patterns when the number of combination patterns does not exceed a predetermined number; The present invention relates to a station placement design support method.

2. obtaining information indicative of a location of at least one first wireless station; calculating a number of combination patterns of at least one first wireless station and at least one candidate installation location of a second wireless station located within a predetermined distance from a location of the first wireless station; If the number of the combination patterns does not exceed a predetermined number, gradually increasing the predetermined distance; When the number of the combination patterns exceeds a predetermined number, outputting the number of the combination patterns based on the predetermined distance in the previous step; The present invention relates to a station placement design support method.

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