JP7583335B2 - Station location design support method and station location design support device - Google Patents

Description

The present invention relates to a station placement design support method and a station placement design support device.

Nowadays, mobile terminals such as smartphones and tablet terminals that can be used outdoors have become widespread. In wireless communication using such mobile terminals, appropriate station placement design and area design are very important issues in terms of convenience and communication efficiency. Station placement design here refers to determining the installation location of a base station that accommodates a mobile terminal (hereinafter referred to as "terminal station"), and area design refers to designing and managing the communication area of the terminal station that is covered by the installed base station.

One method for base station design and area design is to use three-dimensional point cloud data obtained by imaging the space. In this method, three-dimensional point cloud data is acquired by first driving a mobile object, such as a vehicle equipped with an MMS (Mobile Mapping System), along roads surrounding an area to be evaluated, such as a residential area. This method then uses the acquired point cloud data to evaluate whether or not wireless communication between the base station and terminal stations is possible.

For example, Non-Patent Document 1 describes a millimeter wave band station placement design support tool that utilizes point cloud data collected by an MMS to confirm where a millimeter wave band base station should be installed to enable communication between the base station and a terminal station. Also, for example, Patent Document 1 describes a station placement design device that can generate a list of terminal stations that can be accommodated for each combination of multiple base stations placed in an evaluation target area.

In addition, the use of point cloud data collected by the MMS reduces the inspection work of outdoor communication equipment. For example, Non-Patent Document 2 describes a technology that enables the acquisition of three-dimensional point cloud data of outdoor communication equipment using an MMS, and remotely diagnoses the deterioration status of the equipment from the acquired data at a collection center, thereby narrowing down the equipment that requires detailed on-site inspection and reducing the amount of work involved in equipment inspection.

Methods for evaluating the feasibility of wireless communication between a base station and a terminal station include a method for determining the line of sight between the two stations in three dimensions and a method for calculating the shielding rate. The "shielding rate" here is an index that indicates the extent to which an object (hereinafter referred to as "shielding object") that exists between the base station and the terminal station and blocks the passage of radio waves affects wireless communication. From the opposite perspective, this index can also be replaced by "transmittance". In order to evaluate the feasibility of wireless communication using such an evaluation method, it is necessary to have point cloud data for objects that exist in the evaluation area. The evaluation area here includes at least the candidate locations for installing the base station and the locations where the terminal station may exist.

The evaluation of the feasibility of wireless communication between a base station and a terminal station based on the obstruction rate is performed, for example, based on the amount of point cloud data indicating obstructions present within the Fresnel zone formed between the base station and the terminal station. For example, there is a conventional technique for determining whether communication between a base station and a terminal station is possible based on whether the amount of point cloud data present within the Fresnel zone is greater than a predetermined threshold. Station placement design is performed based on the results of such a determination of whether communication is possible.

The range of the evaluation area on the map is divided into a fine mesh pattern, for example. Area design is then performed by determining, for each representative position of each mesh, whether communication is possible with a base station placed at a position determined by the above-mentioned station placement design. This makes it possible to visually show on the map the range in which communication is possible between a base station and a terminal station.

JP 2020-120161 A

“H32 MMS for inspecting access network - Reduce on-site inspection work -”, NTT R&D FORUM 2019, Nippon Telegraph and Telephone East Communication, 2019, [Retrieved August 13, 2021], Internet (URL: https://labevent.ecl.ntt.co.jp/forum2019/elements/pdf_eng/H32_e.pdf) "TsuKuBa History: Millimeter Wave Band Station Design Support Tool", NTT Access Service Systems Laboratories, 2019, [Retrieved August 13, 2021], Internet (URL: https://www.rd.ntt/as/history/pdf/wireless/wi0212.pdf)

For example, when trying to cover a city or the like with a communication network that can connect base stations installed on utility poles and terminal stations that can move to various locations, wireless communication operators may have to perform station placement design and area design for a wide area to be evaluated, for example, several hundred meters square. If such a wide area to be evaluated is divided into fine meshes as described above, the total number of meshes becomes enormous. If it is determined whether communication between base stations and terminal stations is possible for all of these meshes using three-dimensional point cloud data, the amount of calculation required for the calculation process to make this determination becomes enormous. Therefore, there is a problem in that it is necessary to reduce the amount of calculation so that the calculation process required to determine whether communication is possible can be completed within a realistic calculation time.

In view of the above circumstances, the present invention aims to provide a technology that can reduce the amount of calculation required for the computational processing required to determine whether communication is possible while suppressing a decrease in the accuracy of the determination of whether communication is possible.

One aspect of the present invention is a station placement design support method including: an acquisition step of acquiring candidate positions of radio base stations in a target area and representative points representing positions at which a mobile station may be present in each mesh of the target area divided into a mesh shape; a first estimation step of estimating whether communication is possible between the candidate positions of the radio base stations and each of the representative points based on first information indicating positions of objects present in the target area; a determination step of determining, from among combinations of the candidate positions of the radio base stations and the representative points estimated to be communicable by the first estimation step, combinations for which an estimation process of communication possibility is further performed based on second information having a larger amount of information than the first information, the second information being data indicating a position of an obstruction; a second estimation step of estimating whether communication is possible between the candidate positions of the radio base stations and each of the representative points, which are the combinations determined by the determination step, based on the second information; and a termination step of terminating the estimation process by the second estimation step in accordance with a rule defined for each specified station placement design method.

Another aspect of the present invention is a station placement design assistance device including: an acquisition unit that acquires candidate positions of radio base stations in a target area and representative points that represent positions at which a mobile station may be present in each mesh of the target area that is divided into a mesh shape; a first estimation unit that estimates whether communication is possible between the candidate positions of the radio base stations and each of the representative points based on first information that indicates a position of an object present in the target area; a determination unit that determines a combination of combinations of the candidate positions of the radio base stations and the representative points estimated by the first estimation unit as being communicable with each other by further performing an estimation process of whether communication is possible based on second information that has a larger amount of information than the first information and is data that indicates a position of an obstruction; a second estimation unit that estimates whether communication is possible between the candidate positions of the radio base stations and each of the representative points that are the combinations determined by the determination unit, based on the second information; and a termination control unit that terminates the estimation process by the second estimation unit in accordance with a rule defined for a specified station placement design method.

The present invention makes it possible to reduce the amount of calculation required for the computational processing required to determine whether communication is possible while suppressing any decrease in the accuracy of the determination.

1 is a block diagram showing a functional configuration of a station placement and area design support device 1 according to a first embodiment of the present invention. 4 is a flowchart showing an operation of the station placement and area design support device 1 in the first embodiment of the present invention. A figure showing an example of base station installation candidate locations within an evaluation target area and the results of visibility assessment for each mesh. 4 is a flowchart showing an operation of area maximization of station placement and area design supporting device 1 in the first embodiment of the present invention. 13 is a diagram showing an example of updating the determination feasibility list 304 when performing station placement and area design to maximize the area. FIG. 13 is a diagram showing an example of updating the determination feasibility list 304 when performing station placement and area design to maximize the area. FIG. 13 is a diagram showing an example of updating the determination feasibility list 304 when performing station placement and area design to maximize the area. FIG. 13 is a diagram showing an example of updating the determination feasibility list 304 when performing station placement and area design to maximize the area. FIG. 13 is a diagram showing an example of updating the determination feasibility list 304 when performing station placement and area design to maximize the area. FIG. 13 is a diagram showing an example of updating the determination feasibility list 304 when performing station placement and area design to maximize the area. FIG. 13 is a diagram showing an example of updating the determination feasibility list 304 when performing station placement and area design to maximize the area. FIG. 13 is a diagram showing an example of updating the determination feasibility list 304 when performing station placement and area design to improve accommodation efficiency. FIG. 13 is a diagram showing an example of updating the determination feasibility list 304 when performing station placement and area design to improve accommodation efficiency. FIG. 13 is a diagram showing an example of updating the determination feasibility list 304 when performing station placement and area design to improve accommodation efficiency. FIG. 13 is a diagram showing an example of updating the determination feasibility list 304 when performing station placement and area design to improve accommodation efficiency. FIG. 13 is a diagram showing an example of updating the determination feasibility list 304 when performing station placement and area design to improve accommodation efficiency. FIG. 13 is a diagram showing an example of updating the determination feasibility list 304 when performing station placement and area design to improve accommodation efficiency. FIG. 5 is a flowchart showing an operation of a visibility determination process of the station location and area design support device 1 in the first embodiment of the present invention. FIG. 13 is a diagram showing how communication availability is determined taking into account the Fresnel zone fz. 5 is a flowchart showing an operation of station location and area design support device 1 in a visibility determination with priority given to reducing a processing load in the first embodiment of the present invention. 4 is a flowchart showing an operation of the station location and area design support device 1 in the first embodiment of the present invention in determining visibility with priority given to accuracy. 13 is a diagram showing an example of updating the determination feasibility list 304 when performing station placement and area design with priority given to accuracy to maximize area. FIG. 13 is a diagram showing an example of updating the determination feasibility list 304 when performing station placement and area design with priority given to accuracy to maximize area. FIG. 13 is a diagram showing an example of updating the determination feasibility list 304 when performing station placement and area design with priority given to accuracy to maximize area. FIG. 13 is a diagram showing an example of updating the determination feasibility list 304 when performing station placement and area design with priority given to accuracy to maximize area. FIG. 13 is a diagram showing an example of updating the determination feasibility list 304 when performing station placement and area design with priority given to accuracy to maximize area. FIG. 13 is a diagram showing an example of updating the determination feasibility list 304 when performing station placement and area design with priority given to accuracy to improve accommodation efficiency. FIG. 13 is a diagram showing an example of updating the determination feasibility list 304 when performing station placement and area design with priority given to accuracy to improve accommodation efficiency. FIG. 13 is a diagram showing an example of updating the determination feasibility list 304 when performing station placement and area design with priority given to accuracy to improve accommodation efficiency. FIG. 13 is a diagram showing an example of updating the determination feasibility list 304 when performing station placement and area design with priority given to accuracy to improve accommodation efficiency. FIG. 13 is a diagram showing an example of updating the determination feasibility list 304 when performing station placement and area design with priority given to accuracy to improve accommodation efficiency. FIG. 1 is a schematic diagram showing how visibility is determined by regarding the Fresnel zone as a cylinder; 1 is a diagram showing a cylindrical Fresnel zone Cz superimposed on a Fresnel zone fz. 11 is a diagram for explaining a termination condition of a visibility determination process based on point cloud data for a certain base station installation candidate position. FIG. 13 is a flowchart showing an operation of station location and area design support device 1 in a visibility determination with priority given to reducing a processing load according to a third embodiment of the present invention. 13 is a flowchart showing an operation of station location and area design support device 1 in a visibility determination with priority given to reducing a processing load according to a fourth embodiment of the present invention. FIG. 13 is a diagram for explaining station placement and area design in the fifth embodiment of the present invention. FIG. 13 is a diagram for explaining station placement and area design in the fifth embodiment of the present invention.

Below, the station location/area design support method and station location/area design support device in the embodiment will be explained with reference to the drawings.

First Embodiment
Hereinafter, a first embodiment of the present invention will be described. The station placement/area design support device 1 of this embodiment is a device for supporting station placement design that determines the installation position of a base station that accommodates a terminal station present in the area. In addition, the station placement/area design support device 1 is a device for supporting area design that designs and manages a communication area that indicates the range of positions of terminal stations that can communicate with a base station when the base station is installed at a base station installation candidate position (hereinafter referred to as a "base station installation candidate position") derived by the station placement design. In this embodiment, the base station is a wireless base station installed in outdoor equipment such as a high-rise building or a utility pole, and the terminal station is, for example, a mobile wireless terminal. For communication between the base station and the terminal station, for example, unlicensed millimeter wave radio is used.

First, station location and area design support device 1 acquires map information showing a two-dimensional map based on map information. Station location and area design support device 1 divides the map based on the acquired map information into areas in a mesh pattern. For each mesh of the map divided into mesh patterns, station location and area design support device 1 determines (estimates) whether communication between the base station and the terminal station is possible when a terminal station is present in that mesh.

The station location/area design support device 1 outputs station location/area design result information indicating a candidate installation location for at least one base station and the communication area that would be achieved if the base station were installed at the candidate installation location.

The station placement and area design result information output from station placement and area design support device 1 is used in the subsequent station placement design. For example, a station placement design device (not shown) that performs the station placement design determines the installation location of the base station based on the candidate installation locations and communication areas of the base station indicated by the station placement and area design result information output from station placement and area design support device 1.

[Functional configuration of station and area design support device]
The following describes the functional configuration of the station location and area design support device 1. Fig. 1 is a block diagram showing the functional configuration of the station location and area design support device 1 in the first embodiment of the present invention.

As shown in Fig. 1, station location and area design support device 1 includes an equipment information acquisition unit 11, a base station installation candidate location extraction unit 12, a map information acquisition unit 13, an area division unit 14, a point cloud data acquisition unit 15, a data matching unit 16, an operation input unit 20, a memory unit 30, a map visibility determination unit 41, a 3D visibility determination unit 42, a 3D determination feasibility evaluation unit 43, and an output unit 50. Station location and area design support device 1 is an information processing device such as a general-purpose computer.

The facility information acquisition unit 11 acquires facility information, for example, from an external device. Facility information here includes at least information indicating the planar position of outdoor facilities such as high-rise buildings and utility poles on which base stations can be installed. Note that "planar position" here refers to two-dimensional coordinates that do not include coordinates in the height direction (vertical direction). In the following description, planar position may simply be referred to as "position."

The equipment information may further include information indicating the height of the outdoor equipment, or the height at which a base station can be installed in the outdoor equipment. The equipment information acquisition unit 11 outputs the acquired equipment information to the base station installation candidate location extraction unit 12.

The equipment information acquisition unit 11 may acquire the equipment information from an external storage device, or from an external device via a communication network. Alternatively, the equipment information may be pre-stored in the storage unit 30, and the equipment information acquisition unit 11 may acquire the equipment information from the storage unit 30.

In addition, if it is possible to identify the planar position of outdoor equipment such as a high-rise building on which a base station can be installed from the map information acquired by the map information acquisition unit 13 described below, the acquisition of equipment information by the equipment information acquisition unit 11 may be omitted.

The base station installation candidate position extraction unit 12 acquires the equipment information output from the equipment information acquisition unit 11. The base station installation candidate position extraction unit 12 extracts the installation candidate positions of the base station based on the acquired equipment information. For example, the base station installation candidate position extraction unit 12 extracts information indicating the position of a utility pole or the position of a wall of a building above a predetermined height from the acquired equipment information, and sets the position of the utility pole or the position of a wall of a building above a predetermined height as the installation candidate position of the base station. The base station installation candidate position extraction unit 12 stores the base station installation candidate position information 301 indicating the extracted installation candidate positions of the base station in the storage unit 30.

The map information acquisition unit 13 acquires map information, for example, from an external device. The map information here is, for example, information showing a two-dimensional map. The map information includes at least information showing the planar positions of the contours of buildings, such as houses and buildings. The map information may also include information showing the height positions, such as altitude and the height of objects present on the map. The map information acquisition unit 13 outputs the acquired map information to the area division unit 14 and the data matching unit 16.

The map information acquisition unit 13 may acquire the map information from an external storage device, or from an external device via a communication network. Alternatively, the map information may be pre-stored in the storage unit 30, and the map information acquisition unit 13 may acquire the map information from the storage unit 30.

Note that the map information in this embodiment is not a map generated based on point cloud data obtained by, for example, an MMS, but is information based on a general two-dimensional map, such as a residential map produced by a map manufacturer (for example, by surveying, etc.). Therefore, the map information in this embodiment may include, for example, information showing the outlines of buildings, but may not include information regarding the positions of objects other than buildings. Objects other than buildings include, for example, structures such as road signs and billboards, plants such as roadside trees and garden trees, structures such as residential fences and elevated roads, and raised ground.

In this embodiment, the map information may be a map generated based on point cloud data obtained by an MMS or the like. In this case, the map information needs to be data with a smaller amount of information than the three-dimensional point cloud data acquired by the point cloud data acquisition unit 15 described below. In this case, the amount of calculations for the visibility determination process between a base station and a candidate position of a terminal station, which is performed using the map information, is smaller than the amount of calculations for the visibility determination process and the coverage determination process, which are performed using the three-dimensional point cloud data.

The candidate locations for installing the base station may be extracted based on the location of, for example, the outer periphery of a building, which is included in the map information. In this case, the user of the station placement and area design support device 1 (hereinafter referred to as the "user") may visually extract the candidate locations for installing the base station while referring to a map based on the map information.

The area division unit 14 acquires the map information output from the map information acquisition unit 13. The area division unit 14 divides the map based on the acquired map information into meshes of a predetermined size. The area division unit 14 associates the acquired map information with the size and position of the divided meshes and stores them in the memory unit 30. Each mesh is a single area that serves as an evaluation unit, and a process of determining whether communication between the base station and the terminal station is possible is performed for each mesh.

When the area dividing unit 14 acquires the map information output from the map information acquiring unit 13, the area dividing unit 14 may first store the acquired map information as is in the memory unit 30. Then, the area dividing unit 14 may divide the map of only the range of the evaluation target area into a mesh pattern of a predetermined size after a specific range to be the evaluation target area is selected (by the evaluation area selecting unit 201 described later) from the entire range of the map based on the map information stored in the memory unit 30.

The point cloud data acquisition unit 15 acquires point cloud data, for example, from an external device. The point cloud data referred to here is three-dimensional point cloud data obtained by imaging a space. For example, the point cloud data is obtained by driving a mobile object such as a vehicle equipped with an MMS along roads surrounding the residential area to be evaluated. The point cloud data acquisition unit 15 outputs the acquired point cloud data to the data matching unit 16.

The point cloud data acquisition unit 15 may acquire the point cloud data from an external storage device, or from an external device via a communication network. Alternatively, the point cloud data may be pre-stored in the storage unit 30, and the point cloud data acquisition unit 15 may acquire the point cloud data from the storage unit 30.

Note that point cloud data is data with a relatively large amount of information, and in this embodiment, as described above, it is three-dimensional point cloud data obtained, for example, by MMS or the like. The point cloud data includes information indicating the three-dimensional positions of all objects that may be obstructions, including not only buildings but also objects other than buildings that are not included in the map information described above (for example, structures such as road signs and billboards, and plants such as roadside trees and garden trees). Therefore, point cloud data is data with a much larger amount of information than the map information described above. When determining whether communication is possible using point cloud data, the determination accuracy is relatively high, but the amount of calculation required for each determination process is relatively large.

The data matching unit 16 acquires the map information output from the map information acquisition unit 13. The data matching unit 16 also acquires the point cloud data output from the point cloud data acquisition unit 15. The data matching unit 16 achieves consistency between the coordinate system of the map information and the coordinate system of the point cloud data, and, if necessary, corrects the positions (coordinates) included in the point cloud data to be consistent with the positions (coordinates) included in the map information. The data matching unit 16 stores the point cloud data 303, which has been matched with the map information, in the memory unit 30.

If necessary, the data matching unit 16 may correct the base station installation candidate positions included in the base station installation candidate position information 301 stored in the storage unit 30 and the map information included in the map/area information 302 so that they are positions based on the coordinate system of the point cloud data. Generally, a common coordinate system such as the World Geodetic System is often used for the coordinate system of the map information and the coordinate system of the point cloud data, so that coordinate matching processing by the data matching unit 16 is often not required.

The operation input unit 20 accepts input operations by a user. The operation input unit 20 is configured to include an input interface such as an input button, a keyboard, a mouse, and a touch panel. As shown in FIG. 1, the operation input unit 20 is configured to include an evaluation area selection unit 201, a base station candidate position selection unit 202, a design method designation unit 203, and a processing mode designation unit 204.

The evaluation area selection unit 201 accepts an input operation by a user to specify an evaluation target area for which station placement and area design is to be performed within the entire range of a map based on map information. The evaluation area selection unit 201 stores information indicating the evaluation target area indicated by the accepted input operation in the memory unit 30. Note that the evaluation area selection unit 201 may add information specifying the evaluation target area to the map information acquired by the map information acquisition unit 13 and stored in the memory unit 30 as map and area information 302.

When specifying the area to be evaluated, the user specifies the area to be evaluated while looking at a map displayed on a display device (not shown), such as a liquid crystal display (LCD) or an organic electroluminescence (EL) display. The display device referred to here may be one of the components constituting the output unit 50 described below.

The base station candidate location selection unit 202 accepts an input operation by a user to select at least one specific base station installation candidate location to be evaluated from among the base station installation candidate locations (extracted by the base station installation candidate location extraction unit 12) included in the evaluation target area. The base station candidate location selection unit 202 stores information indicating the base station installation candidate location indicated by the accepted input operation in the storage unit 30.

The base station candidate position selection unit 202 may update the base station installation candidate position information 301, which is information indicating a plurality of base station installation candidate positions extracted by the base station installation candidate position extraction unit 12 and stored in the storage unit 30. Specifically, the base station candidate position selection unit 202 may attach a flag that can identify the base station installation candidate position selected by the user to the plurality of base station installation candidate positions included in the base station installation candidate position information 301.

When selecting a base station installation candidate location, the user selects at least one specific base station installation candidate location while viewing a plurality of base station installation candidate locations included in a map of the area to be evaluated, displayed on a display device (not shown), such as a liquid crystal display or an organic EL display. The display device referred to here may be one of the components constituting the output unit 50 described below.

The design method specification unit 203 accepts an input operation by a user to specify a method of station placement and area design (hereinafter referred to as the "design method"). The design method specification unit 203 stores information indicating the design method indicated by the accepted input operation in the memory unit 30.

The design method referred to here includes at least the following two methods. The first design method is a method of designing stations and areas to maximize the area that can accommodate terminal stations (communication area) (hereinafter referred to as "area maximization"). The second design method is a method of designing stations and areas efficiently by making the area that can accommodate terminal stations relatively large while using a smaller number of base stations (hereinafter referred to as "accommodation efficiency"). Details of the above two design methods will be described later.

When specifying a design method, the user selects one design method by viewing wording (e.g., "area maximization" and "accommodation efficiency") or images indicating at least two design methods displayed on a display device (not shown), such as a liquid crystal display or an organic electroluminescence display. The display device referred to here may be one of the components constituting the output unit 50 described below.

The processing mode designation unit 204 accepts an input operation by a user to designate a processing mode when performing station placement and area design processing. The processing mode designation unit 204 stores information indicating the processing mode indicated by the accepted input operation in the storage unit 30.

The processing modes referred to here include at least the following two modes. The first processing mode is a mode that prioritizes reducing the processing load in the station placement and area design process (hereinafter referred to as the "processing load reduction priority mode"). The second processing mode is a mode that prioritizes increasing the processing accuracy in the station placement and area design process (hereinafter referred to as the "accuracy priority mode"). Details of the above two processing modes will be described later.

When specifying a processing mode, the user selects one processing mode by viewing words (e.g., "processing load reduction priority mode" and "accuracy priority mode") or images indicating at least two processing modes displayed on a display device (not shown), such as a liquid crystal display or an organic EL display. The display device referred to here may be one of the components constituting the output unit 50 described below.

The storage unit 30 stores base station installation candidate location information 301, map and area information 302, point cloud data 303, a judgment feasibility list 304, and station installation and area design result information 305. The storage unit 30 is configured, for example, by a storage medium such as a hard disk drive (HDD), a flash memory, an electrically erasable programmable read only memory (EEPROM), a random access read/write memory (RAM), a read only memory (ROM), or any combination of these storage media.

The base station installation candidate position information 301 is information indicating at least one base station installation candidate position that is extracted by the base station installation candidate position extraction unit 12 and stored in the storage unit 30. Of the base station installation candidate positions included in the base station installation candidate position information 301, the base station installation candidate position selected by the user by the base station installation candidate position selection unit 202 is flagged. Alternatively, of the base station installation candidate positions included in the base station installation candidate position information 301, information indicating the base station installation candidate positions that were not selected by the user by the base station installation candidate position selection unit 202 may be deleted.

Map/area information 302 is information that corresponds map information acquired by the map information acquisition unit 13 with information indicating the size and position of the mesh when the map information is divided into a mesh by the area division unit 14.

The point cloud data 303 is information based on three-dimensional point cloud data acquired by the point cloud data acquisition unit 15. The range on the map indicated by the point cloud data 303 overlaps with the range of the map based on the map information acquired by the map information acquisition unit 13. The point cloud data 303 is point cloud data that has been adjusted by the data adjustment unit 16 to match the coordinate system of the map information with the coordinate system of the point cloud data, and has been corrected as necessary to match positions (coordinates) included in the map information.

In addition, the memory unit 30 does not need to store all base station installation candidate location information 301 and all point cloud data 303 within the evaluation target area, but only needs to store base station installation candidate location information 301 and point cloud data 303 that includes at least the range required for the station placement and area design process within the range on the map that can be selected as the evaluation target area by the evaluation area selection unit 201.

The determination feasibility list 304 is a list of combinations of candidate installation locations for base stations and candidate locations for terminal stations. Each combination of candidate installation locations for base stations and candidate locations for terminal stations included in the determination feasibility list 304 is associated with information indicating the result of a (e.g., two-dimensional) visibility determination based on map information determined by the map visibility determination unit 41, and information indicating the result of a visibility determination or a shielding rate determination based on three-dimensional point cloud data determined by the three-dimensional visibility determination unit 42.

The station location/area design result information 305 is information indicating the results of the station location/area design process generated by the map visibility determination unit 41 and the 3D visibility determination unit 42 described below.

The map visibility assessment unit 41 performs visibility assessment for each mesh of the evaluation area of the map, which is divided into a mesh pattern based on the map/area information 302 stored in the memory unit 30, based on the map information.

Specifically, the map visibility determination unit 41 performs a visibility determination based on map information between each base station when the base station is installed at the base station installation candidate position extracted by the base station installation candidate position extraction unit 12 and selected by the base station installation candidate position selection unit 202, and a terminal station when the terminal station is located at a position that represents each mesh (hereinafter referred to as a "representative point"). For example, the map visibility determination unit 41 performs a visibility determination between the base station installation candidate position and the representative point based on the position of the outline of an object such as a building included in the map information.

The representative point is, for example, a position at the center of a mesh. In other words, when the map visibility determination unit 41 performs visibility determination for each mesh, it performs the visibility determination assuming that a terminal station is located at the center of the mesh.

The position of the representative point is not limited to the center of the mesh, but may be other positions, such as a corner of the mesh. However, if the representative point is located at a corner of the mesh, there may be positions within the mesh that are far away from the representative point, such as another corner diagonally across from the mesh, which is likely to result in a large error in determining whether communication is possible. Therefore, it is desirable for the representative point to be located at the center of the mesh.

Here, the presence or absence of line of sight refers to whether or not there is an obstruction blocking the propagation of radio waves transmitted and received between the base station and the terminal station, assuming that the base station and terminal station are located at the candidate installation location of the base station and the representative point of each mesh, respectively. If there is no obstruction blocking the radio waves on the propagation path between the base station and the terminal station, it is said that there is "line of sight," and if there is an obstruction blocking the radio waves on the propagation path between the base station and the terminal station, it is said that there is "no line of sight."

In this embodiment, the visibility determination and the estimation of whether communication is possible are considered to be equivalent. In other words, the determination that there is visibility is equivalent to the estimation that communication is possible, and the determination that there is no visibility is equivalent to the estimation that communication is not possible.

Note that an obstruction here refers to an object that may block the propagation of radio waves transmitted and received between a base station and a terminal station. Obstructions include any object that may block the propagation of radio waves, such as buildings (architectures) such as dwellings and buildings, structures such as residential fences and elevated roads, structures such as road signs and billboards, plants such as roadside trees and garden trees, and raised ground.

The three-dimensional visibility assessment unit 42 performs visibility assessment for each mesh of the range of the evaluation target area of the map, which is divided into a mesh pattern based on the map/area information 302 stored in the memory unit 30, based on the point cloud data 303.

Specifically, the three-dimensional visibility assessment unit 42 performs a visibility assessment based on three-dimensional point cloud data between each base station when the base station is installed at a base station installation candidate location selected by the base station candidate location selection unit 202 and determined to have visibility based on map information by the map visibility assessment unit 41, and the terminal station when the terminal station is located at the representative point of each mesh.

As mentioned above, the presence or absence of line of sight refers to whether or not there is an obstruction that blocks the propagation of radio waves transmitted and received between a base station and a terminal station in the propagation path of the radio waves transmitted and received between the base station and the terminal station when the base station and terminal station are located at the candidate installation location of the base station and the representative point of each mesh, respectively. An obstruction is an object that has the potential to block the propagation of radio waves transmitted and received between the base station and the terminal station.

The 3D visibility determination unit 42 performs visibility determination for combinations that are determined to require visibility determination based on 3D point cloud data among combinations of base station installation candidate locations and representative points of each mesh that are determined to have visibility by the map information-based visibility determination by the map visibility determination unit 41. Which combinations are determined by the map visibility determination unit 41 to require visibility determination based on 3D point cloud data depends on the design method of station placement and area design specified by the design method designation unit 203. Details of each design method will be described later.

The 3D visibility determination unit 42 determines whether the number of acquired 3D point cloud data between the base station installation candidate location that is the subject of the visibility determination and the representative point is greater than a predetermined threshold. The 3D determination feasibility evaluation unit 43 determines that there is visibility when the number of acquired 3D point cloud data is equal to or less than the predetermined threshold.

In addition, when the number of acquired three-dimensional point cloud data is greater than a predetermined threshold, the three-dimensional judgment feasibility evaluation unit 43 performs a visibility judgment using the three-dimensional point cloud data while taking into account the obscuration rate. In other words, even if there is a lot of point cloud data between the candidate base station installation location and the representative point (i.e., even if there are many or large obstructions), the three-dimensional visibility judgment unit 42 does not immediately determine that there is no visibility, but rather performs the visibility judgment while further taking into account the obscuration rate, thereby obtaining a more accurate visibility judgment result.

For example, the base station installation candidate location extraction unit 12, area division unit 14, data matching unit 16, map visibility determination unit 41, and 3D visibility determination unit 42 may be configured as components of a single control unit (not shown). In this case, the control unit is realized, for example, by a hardware processor such as a CPU (Central Processing Unit) executing a program (software). Alternatively, the control unit may be configured to be realized by collaboration between software and hardware. The program read by the CPU may be stored in advance in a storage medium such as the storage unit 30 provided in the station placement/area design support device 1.

The 3D judgment feasibility evaluation unit 43 checks whether the proportion of 3D point cloud data collected for the mesh area on a map that includes the candidate base station installation locations included in the judgment feasibility list 304 and the surrounding area, and for the mesh area on a map that includes the representative point included in the representative point judgment feasibility list 304 and the surrounding area, is sufficient to enable visibility judgment.

The 3D determination feasibility evaluation unit 43 excludes base station installation candidate locations and representative points that are within a mesh range where the proportion of collected 3D point cloud data does not reach a proportion that allows for line of sight determination from the targets of line of sight determination processing based on point cloud data. This is because, for areas where a sufficient amount of 3D data has not been collected, even if line of sight determination is performed based on 3D point cloud data, a line of sight determination result with sufficient reliability cannot be obtained. The 3D determination feasibility evaluation unit 43 excludes the relevant base station installation candidate locations and representative points from the targets of line of sight determination processing, for example, by updating the determination feasibility list 304.

The output unit 50 acquires the station placement/area design result information 305 from the memory unit 30. The output unit 50 outputs the station placement/area design result information 305 to an external device (e.g., a station placement design device, etc.) that performs subsequent processing.

The output unit 50 is configured to include, for example, a communication interface for outputting the station placement and area design result information 305 to an external device. The output unit 50 may be a functional unit that functions as a display unit that displays the station placement and area design result information 305. In this case, the output unit 50 is configured to include, for example, a display device such as a liquid crystal display or an organic EL display. The output unit 50 may be configured to display various information to be presented to the user.

In addition, according to the processing shown in the flowchart of Figure 2 described below, the following two points can be achieved.

Deriving recommended combinations of base station candidate locations.
- Derive the communication area according to the reliability.

The reliability referred to here includes, for example, a standard reliability equivalent to an evaluation using (preferentially) two-dimensional map information including information such as the location of the building's exterior, and a higher reliability equivalent to an evaluation using (preferentially) three-dimensional point cloud data collected by an MMS.

In order to derive recommended base station installation locations and terminal station communication areas, the decision as to which information (data) to preferentially use, between the two-dimensional map information and the three-dimensional point cloud data, is made based on factors such as the collection status of the three-dimensional point cloud data, which is affected by the driving route of the MMS, etc.

[Operation of station location and area design support device]
Hereinafter, a description will be given of an example of the operation of the station location and area design support device 1. Fig. 2 is a flowchart showing the operation of the station location and area design support device 1 in the first embodiment of the present invention. The operation of the station location and area design support device 1 shown in the flowchart of Fig. 2 starts, for example, when the power of the station location and area design support device 1 is turned on.

First, the map information acquisition unit 13 acquires map information, for example, from an external device (step S01). As described above, the map information here is, for example, information indicating a two-dimensional map. The map information includes at least information indicating the planar position of the outer periphery of buildings, such as houses and buildings. Map information is data with a smaller amount of information than three-dimensional point cloud data. Therefore, the visibility determination process performed using map information requires less calculations than the visibility determination process performed using three-dimensional point cloud data.

Next, the evaluation area selection unit 201 accepts an input operation by the user to select an evaluation target area for station placement and area design from the entire range of the map based on the map information (step S02). For example, the user selects the evaluation target area by performing an input operation to surround a desired range on a map displayed on a display device (not shown).

The evaluation area selection unit 201 stores information indicating the evaluation target area indicated by the received input operation in the storage unit 30. The area division unit 14 divides the map of the range of the evaluation target area into a mesh pattern of a predetermined size based on the map information output from the map information acquisition unit 13 and the information indicating the evaluation target area selected by the evaluation area selection unit 201.

Next, the equipment information acquisition unit 11 acquires equipment information, for example, from an external device (step S03). As described above, the equipment information here includes at least information indicating the planar positions of outdoor equipment, such as high-rise buildings and utility poles, on which base stations can be installed. The base station installation candidate position extraction unit 12 extracts base station installation candidate positions based on the acquired equipment information (step S04). The base station installation candidate position extraction unit 12 stores base station installation candidate position information 301 indicating the extracted base station installation candidate positions in the storage unit 30.

In addition, if the map information includes information indicating the height position, such as altitude and the height of objects present on the map, points above a predetermined height and the positions of buildings, etc. above a predetermined height may be automatically extracted as candidate locations for installing base stations.

Next, the base station candidate position selection unit 202 accepts an input operation by the user to select at least one specific base station installation candidate position to be evaluated from among the base station installation candidate positions extracted by the base station installation candidate position extraction unit 12 (step S05). For example, a map of the evaluation target area may be displayed on a display device (not shown) or the like, and the user may select a desired position as the base station installation candidate position using the operation input unit 20. The base station candidate position selection unit 202 stores information indicating the evaluation target area indicated by the accepted input operation in the storage unit 30.

In addition, the base station candidate location selection unit 202 may be configured to select the base station installation candidate location by reading, from an external device, a data file in, for example, a CSV (Comma Separated Value) format indicating a list of base station installation candidate locations (e.g., latitude and longitude for each base station installation candidate location).

Next, the map visibility determination unit 41 performs a visibility determination based on the map information for each mesh of the range of the evaluation area of the map, which is divided into a mesh based on the map/area information 302 stored in the memory unit 30 (step S06). The map visibility determination unit 41 performs a visibility determination based on the map information for each base station when a base station is installed at the selected base station installation candidate location, and a terminal station when the terminal station is located at each representative point. As mentioned above, the representative point is, for example, the center position of the mesh. For example, the map visibility determination unit 41 performs a visibility determination based on the position of the outline of an object such as a building included in the map information.

Next, the output unit 50 or a display device (not shown) provided in the station location/area design support device 1 displays information indicating the result of the visibility judgment based on the map information by the map visibility judgment unit 41 in a manner that can be referenced by the user (step S07).

Next, the point cloud data acquisition unit 15 acquires point cloud data, for example, from an external device (step S08). As described above, the point cloud data is obtained, for example, by driving a mobile object such as a vehicle equipped with an MMS along roads around an area to be evaluated, such as a residential area.

Note that the point cloud data acquisition unit 15 may acquire three-dimensional point cloud data limited to a range necessary and sufficient for visibility determination, instead of acquiring all three-dimensional point cloud data of the map based on the map information. Specifically, for example, the point cloud data acquisition unit 15 may acquire only three-dimensional point cloud data of a range required for performing visibility determination for a combination of a base station installation candidate position and a representative point position that have been determined to have visibility by the map information-based visibility determination unit 41.

Alternatively, for example, the point cloud data acquisition unit 15 may acquire only the three-dimensional point cloud data of the range required to perform visibility assessment for the combination of the candidate base station installation location and the representative point location for which it has been determined that visibility assessment based on three-dimensional point cloud data is necessary in accordance with the design method of the specified station/area design.

Next, the data matching unit 16 acquires map information of the area to be evaluated, which is included in the map/area information 302. The data matching unit 16 also acquires the point cloud data output from the point cloud data acquisition unit 15. The data matching unit 16 attempts to achieve consistency between the coordinate system of the map information and the coordinate system of the point cloud data, and, if necessary, corrects the positions (coordinates) included in the point cloud data so that they are consistent with the positions (coordinates) included in the map information (step S09). The data matching unit 16 stores the point cloud data 303, which has been matched with the map information, in the storage unit 30. Note that if it is known that the coordinate system of the map information and the coordinate system of the point cloud data match, the processing of step S09 can be omitted.

Next, the three-dimensional visibility assessment unit 42 creates a judgment feasibility list 304 indicating whether or not visibility assessment based on three-dimensional point cloud data is necessary for each candidate base station installation location based on the results of the visibility assessment based on map information by the map visibility assessment unit 41 (step S10).

Next, the three-dimensional visibility determination unit 42 creates a determination possibility list 304 indicating whether or not visibility determination based on three-dimensional point cloud data is necessary for each representative point based on the results of the visibility determination based on map information by the map visibility determination unit 41 (step S11). As described above, a representative point is a position that represents each mesh of a map divided into a mesh pattern (for example, the center position of the mesh). In the visibility determination process based on map information and the visibility determination process based on three-dimensional point cloud data, visibility is determined assuming that a terminal station exists at the representative point.

Next, the 3D determination feasibility evaluation unit 43 checks whether the proportion of collected 3D point cloud data for the mesh range on the map including the base station installation candidate locations included in the determination feasibility list 304 and the mesh range on the map including the representative point included in the determination feasibility list 304 has reached a proportion that allows for line of sight determination (step S12). The 3D determination feasibility evaluation unit 43 updates the determination feasibility list 304 to exclude from the line of sight determination the base station installation candidate locations and representative points that exist within the mesh range for which the proportion of collected 3D point cloud data has not reached a proportion that allows for line of sight determination.

The user may visually check whether the proportion of collected 3D point cloud data has reached a proportion that allows visibility assessment. For example, the proportion of collected 3D point cloud data for each mesh may be displayed on a display device (not shown) provided in the station placement/area design support device 1. The user may then check the proportion and determine whether or not to exclude each mesh from the visibility assessment, and specify this through an input operation.

Next, the design method designation unit 203 accepts an input operation by the user to designate the design method (step S13). As described above, the design methods include two design methods: "area maximization" and "accommodation efficiency." Area maximization is a method of station placement and area design that maximizes the area that can accommodate terminal stations. Accommodation efficiency is a method of efficient station placement and area design by making the area that can accommodate terminal stations relatively large while using a smaller number of base stations.

Next, if "area maximization" is specified by the design method specification unit 203 (step S13, YES), the map visibility determination unit 41 executes the processing of the following step S14. On the other hand, if "accommodation efficiency" is specified by the design method specification unit 203 (step S13, NO), the map visibility determination unit 41 omits execution of the processing of the following step S14.

Next, the map visibility determination unit 41 performs a visibility determination based on map information for each mesh on the map of the evaluation area, which is divided into a mesh pattern, in the case where a base station is installed at each of the base station installation candidate locations selected in step S05 above.

The map visibility determination unit 41 identifies representative points (mesh) that are determined to be covered as a communication area by a base station installed at a certain base station installation candidate location (i.e., determined to have visibility) by a visibility determination based on map information, and that are determined not to be covered as a communication area by a base station installed at any other base station installation candidate location (i.e., determined to have no visibility). The map visibility determination unit 41 selects a base station installation candidate location that covers the identified representative points (mesh) as a communication area (step S14). Details of this step S14 will be explained in detail later with specific examples.

Next, the processing mode designation unit 204 accepts an input operation by the user to designate a processing mode when performing station placement and area design processing (step S15). As described above, the processing modes include two modes: a "processing burden reduction priority mode" and a "accuracy priority mode". The processing burden reduction priority mode is a mode that prioritizes reducing the processing burden in the station placement and area design processing. The accuracy priority mode is a mode that prioritizes increasing the processing accuracy in the station placement and area design processing.

Next, when the processing mode designation unit 204 designates the "processing load reduction priority mode" (step S15, YES), the map visibility determination unit 41 and the 3D visibility determination unit 42 perform visibility determination with a priority on reducing the processing load (step S16). On the other hand, when the processing mode designation unit 204 designates the "accuracy priority mode" (step S15, NO), the map visibility determination unit 41 and the 3D visibility determination unit 42 perform visibility determination with a priority on increasing the processing accuracy (step S17).

Here, visibility assessment that prioritizes reducing the processing load refers to a method of determining the final visibility assessment result by prioritizing the results of visibility assessment based on (e.g., two-dimensional) map information. This method of assessment makes it possible to obtain the results of visibility assessment more quickly compared to visibility assessment that prioritizes high assessment accuracy.

On the other hand, visibility assessment that prioritizes high assessment accuracy is a method of determining the final visibility assessment result by prioritizing the results of visibility assessment based on (e.g., three-dimensional) point cloud data. This method of assessment makes it possible to obtain more accurate visibility assessment results compared to visibility assessment that prioritizes reducing the processing load.

Next, the output unit 50 displays station location and area design result information 305 (step S18), which indicates the results of the visibility assessment performed (by the map visibility assessment unit 41 and the 3D visibility assessment unit 42) according to the specified design method (i.e., "area maximization" or "accommodation efficiency") and the specified processing mode (i.e., "processing burden reduction priority mode" or "accuracy priority mode"). This completes the operation of the station location and area design support device 1 shown in the flowchart of Figure 2.

[Whether visibility can be judged based on point cloud data]
A method for determining whether or not visibility assessment can be performed based on point cloud data will be described in detail below with reference to a specific example.

Figure 3 shows an example of candidate base station installation locations within an evaluation target area and the results of visibility assessment for each mesh. A 7-row x 8-column grid is depicted in Figure 3, which represents a portion of the evaluation target area on a map based on map information divided into a mesh pattern. In addition, in Figure 3, the black dots labeled "A" through "E" respectively represent candidate base station installation locations selected by the base station candidate location selection unit 202.

In FIG. 3, the six meshes surrounded by bold solid lines (i.e., the meshes numbered (1), (2), (3), (4), (5), and (6) respectively) are meshes that have been determined to have line of sight to the base station installation candidate location A through a line of sight determination based on map information by the map line of sight determination unit 41. In other words, this means that the base station to be installed at the base station installation candidate location A will be able to communicate with terminal stations present within the range of the six meshes numbered (1), (2), (3), (4), (5), and (6) respectively.

In addition, in FIG. 3, the five meshes surrounded by dotted lines (i.e., the meshes numbered (2), (3), (4), (5), and (7) respectively) are meshes that have been determined to have line of sight to base station installation candidate location B through a line of sight determination based on map information by the map line of sight determination unit 41. In other words, this means that the base station to be installed at base station installation candidate location B will be able to communicate with terminal stations present within the range of the five meshes numbered (2), (3), (4), (5), and (7) respectively.

In addition, in FIG. 3, the four meshes surrounded by dashed dotted lines (i.e., the meshes numbered (6), (8), (10), and (12) respectively) are meshes that have been determined to have line of sight to the base station installation candidate location C through a line of sight determination based on map information by the map line of sight determination unit 41. In other words, this means that the base station to be installed at the base station installation candidate location C will be able to communicate with terminal stations present within the range of the four meshes numbered (6), (8), (10), and (12) respectively.

In addition, in FIG. 3, the five meshes surrounded by dashed lines (i.e., the meshes numbered (8), (9), (10), (11), and (13) respectively) are meshes that have been determined to have line of sight to the base station installation candidate location D through a line of sight determination based on map information by the map line of sight determination unit 41. In other words, this means that the base station to be installed at the base station installation candidate location D will be able to communicate with terminal stations present within the range of the five meshes numbered (8), (9), (10), (11), and (13) respectively.

In addition, in Figure 3, the two meshes surrounded by a two-dot dashed line (i.e., the meshes numbered (13) and (14) respectively) are meshes that have been determined to have line of sight to the base station installation candidate location E through a line of sight determination based on map information by the map line of sight determination unit 41. In other words, this means that the base station to be installed at the base station installation candidate location E will be able to communicate with terminal stations present within the range of the two meshes numbered (13) and (14) respectively.

In Figure 3, blank meshes that do not have symbols such as "(1)" through "(14)" are meshes that have representative points that have been determined to have no line of sight to any of the candidate base station installation locations A through E through a line of sight determination based on map information. In other words, this means that no matter which base station is installed within any of the candidate base station installation locations A through E, the base station will not be able to communicate with terminal stations that exist within the blank mesh range. Therefore, for the representative points of such blank meshes, there is no need to perform line of sight determination processing based on point cloud data by the subsequent three-dimensional line of sight determination unit 42.

The visibility assessment based on map information is performed, for example, based on whether or not there is an obstruction such as a building on the line connecting the candidate base station installation location and the representative point of the mesh on the map. Any conventional technology can be used to assess the visibility based on map information.

Below, we will explain station placement and area design when "area maximization" is specified as the design method. As mentioned above, area maximization is a method of station placement and area design that maximizes the area that can accommodate terminal stations.

When performing station placement and area design to maximize coverage, the map visibility determination unit 41 identifies representative points that have been determined to have visibility to only one candidate base station installation location among representative points that have been determined to have visibility to at least one candidate base station installation location through a visibility determination based on map information.

In the example shown in Figure 3, the representative points that were determined to have line of sight between only one candidate base station installation location based on the line of sight judgment based on map information are the representative points marked with the symbols (1), (7), (9), (11), (12), and (14).

As shown in FIG. 3, the representative point marked with (1) is a representative point that has been determined to have line of sight only to base station installation candidate location A through a line of sight determination based on map information. Similarly, the representative point marked with (7) is a representative point that has been determined to have line of sight only to base station installation candidate location B through a line of sight determination based on map information. The representative points marked with (9) and (11) are representative points that have been determined to have line of sight only to base station installation candidate location D through a line of sight determination based on map information. The representative point marked with (12) is a representative point that has been determined to have line of sight only to base station installation candidate location C through a line of sight determination based on map information. The representative point marked with (14) is a representative point that has been determined to have line of sight only to base station installation candidate location E through a line of sight determination based on map information.

When performing station placement and area design to maximize coverage, the map visibility determination unit 41 preferentially (first) selects a base station installation candidate location that is determined to have visibility to the above-mentioned identified representative point as a base station installation candidate location to be used in the subsequent visibility determination process based on the three-dimensional point cloud data. Note that, as described above, the above-mentioned identified representative point is a representative point that is determined to have visibility to only one base station installation candidate location.

In other words, when performing station placement and area design to maximize coverage area, the map visibility determination unit 41 identifies representative points (mesh) that are determined to be covered as a communication area by a base station installed at a certain base station installation candidate location (i.e., determined to have line of sight) through a visibility determination based on map information, among the representative points (mesh) that are determined to be covered as a communication area by a base station installed at a certain base station installation candidate location (i.e., determined to have line of sight), and that are determined not to be covered as a communication area by a base station installed at any other base station installation candidate location (i.e., determined to have no line of sight). The map visibility determination unit 41 preferentially (first) selects a base station installation candidate location that covers the identified representative points (mesh) as a communication area.

In order to design stations and areas so as to maximize the area capable of accommodating terminal stations, it is necessary to identify a representative point that is determined to have line of sight to only one candidate base station installation location through a line of sight assessment based on map information, and to preferentially select the candidate base station installation location that is determined to have line of sight to that representative point as the candidate base station installation location to be used in the subsequent line of sight assessment process based on three-dimensional point cloud data.

In contrast, below we will explain station placement and area design when "accommodation efficiency" is specified as the design method. As mentioned above, accommodation efficiency is a method of efficient station placement and area design by making the area that can accommodate terminal stations relatively large while using a smaller number of base stations.

When designing base stations and areas to improve capacity efficiency, the map visibility determination unit 41 prioritizes base station installation candidate locations that have the most representative points that are determined to have visibility based on map information, as base station installation candidate locations to be used in the subsequent visibility determination process based on three-dimensional point cloud data.

When designing stations and areas to improve capacity, the map visibility determination unit 41 ends the above process of selecting a base station candidate location to be used in the subsequent visibility determination process based on three-dimensional point cloud data when the proportion of selected representative points (mesh) that have been determined to have visibility to at least one base station candidate location by the visibility determination based on map information reaches a predetermined proportion. The predetermined proportion is, for example, 80%. This configuration improves capacity efficiency by making the area that can accommodate terminal stations relatively wide while using a smaller number of base stations.

For example, in FIG. 3, base station installation candidate location A has the most representative points that are determined to have visibility based on map information. Base station installation candidate location A has visibility to each of the six representative points marked with the symbols (1), (2), (3), (4), (5), and (6). Next, base station installation candidate locations B and D have the second most representative points that are determined to have visibility based on map information. Base station installation candidate location B has visibility to each of the five representative points marked with the symbols (2), (3), (4), (5), and (7), and base station installation candidate location D has visibility to each of the five representative points marked with the symbols (8), (9), (10), (11), and (13). Next, base station installation candidate location C has the third most representative points that are determined to have visibility based on map information. Base station installation candidate location C has line of sight to each of the four representative points marked with symbols (6), (8), (10), and (12). Finally, base station installation candidate location E has the fewest number of representative points that are determined to have line of sight based on map information. Base station installation candidate location E has line of sight to each of the two representative points marked with symbols (13) and (14).

When designing base stations and areas to improve capacity efficiency, the map visibility determination unit 41 first selects the base station installation candidate location A that has the most representative points that have been determined to have visibility based on the visibility determination based on map information, as the base station installation candidate location to be used in the subsequent visibility determination process based on three-dimensional point cloud data.

Next, the base station installation candidate locations B and D initially had the second largest number of representative points that were determined to have line of sight based on map information. However, for example, base station installation candidate location B was determined to have line of sight to the five representative points marked with the symbols (2), (3), (4), (5), and (7), and of these, the four representative points marked with the symbols (2), (3), (4), and (5) were also determined to have line of sight to the selected base station installation candidate location A.

Therefore, even if base station installation candidate location A is selected and then base station installation candidate location B is selected, only the representative point marked with the symbol (7) will be newly added as a representative point with line of sight to any of the base station installation candidate locations. Therefore, if base station installation candidate location B is selected after base station installation candidate location A is selected, it will not be in line with the objective of improving capacity efficiency.

Therefore, the map visibility determination unit 41 excludes representative points that have been determined to have visibility between the already selected base station installation candidate locations through a visibility determination based on map information, and selects the base station installation candidate location that has the largest number of representative points that have been determined to have visibility as the base station installation candidate location to be used in the subsequent visibility determination process based on three-dimensional point cloud data.

Therefore, when base station installation candidate location A is selected and the representative points that are determined to have line of sight to base station installation candidate location A are removed, base station installation candidate location B has line of sight to one representative point marked with the symbol (7), base station installation candidate location C has line of sight to three representative points marked with the symbols (8), (10), and (12), base station installation candidate location D has line of sight to five representative points marked with the symbols (8), (9), (10), (11), and (13), and base station installation candidate location E has line of sight to two representative points marked with the symbols (13) and (14).

From the above results, after base station installation candidate location A is selected, base station installation candidate location D, which has line of sight to five representative points, has the most representative points that are determined to have line of sight by a line of sight determination based on map information. After base station installation candidate location A, the map line of sight determination unit 41 additionally selects base station installation candidate location D as a base station installation candidate location to be used in the subsequent line of sight determination process based on three-dimensional point cloud data.

Then, when base station installation candidate locations A and D have been selected and the representative points that have been determined to have line of sight to base station installation candidate locations A or D have been removed, base station installation candidate location B has line of sight to the single representative point marked with the symbol (7), base station installation candidate location C has line of sight to the single representative point marked with the symbol (12), and base station installation candidate location E has line of sight to the single representative point marked with the symbol (14).

At this time, since each of the base station installation candidate locations B, C, and E has one representative point that has been determined to have visibility by a visibility assessment based on map information, the map visibility assessment unit 41 additionally selects one of the remaining base station installation candidate locations (here, for example, base station installation candidate location B) after base station installation candidate location D as a base station installation candidate location to be used in the subsequent visibility assessment process based on three-dimensional point cloud data.

By selecting the base station installation candidate locations A, D, and B, the 12 representative points marked with the symbols (1), (2), (3), (4), (5), (6), (7), (8), (9), (10), (11), and (13) respectively become representative points that are determined to have line of sight to any of the selected base station installation candidate locations (i.e., any of the base station installation candidate locations A, D, and C).

Here, in the evaluation area illustrated in Figure 3, the representative points (mesh) that have been determined to have line of sight to any of the base station installation candidate locations A to E in the evaluation area based on a line of sight determination based on map information are the 14 representative points marked with the numbers (1) to (14), totaling 14. Therefore, by selecting the base station installation candidate locations A, D, and B, 12 of the 14 representative points are covered as communication-enabled areas.

The ratio of 12 out of 14 is approximately 86% and, for example, has reached a predetermined ratio of 80%. Therefore, when the map visibility determination unit 41 selects the three base station installation candidate locations A, D, and C in that order, it ends the above process of selecting the base station installation candidate locations to be used in the visibility determination process based on the three-dimensional point cloud data in the subsequent stage. With this configuration, it is possible to improve the accommodation efficiency by making the area that can accommodate terminal stations relatively wide while using a smaller number of base stations.

In the station placement and area design when the aforementioned "area maximization" is specified, the map line-of-sight determination unit 41 first identifies representative points (mesh) that are determined to be covered as a communication area by a base station installed at a certain base station placement candidate location (i.e., determined to have line-of-sight) by a line-of-sight determination based on map information, and is determined not to be covered as a communication area by any base station installed at any other base station placement candidate location (i.e., determined to have no line-of-sight), and then preferentially selects a base station placement candidate location that covers the identified representative points (mesh) as a communication area. In the station placement and area design when "area maximization" is specified, the map line-of-sight determination unit 41 may perform the same process as the station placement and area design when the aforementioned "accommodation efficiency" is specified in the subsequent selection of base station placement candidate locations.

That is, the map visibility determination unit 41 first identifies a representative point that is determined to have visibility to only one base station installation candidate location by a visibility determination based on map information, and selects all base station installation candidate locations that are determined to have visibility to the representative point as base station installation candidate locations to be used in the visibility determination process based on three-dimensional point cloud data at the subsequent stage. Thereafter, the map visibility determination unit 41 prioritizes the selection of base station installation candidate locations to be used in the visibility determination process based on three-dimensional point cloud data at the subsequent stage, starting from the base station installation candidate locations that have the most representative points that are determined to have visibility by a visibility determination based on map information.

Here, the map visibility determination unit 41 may terminate the above process of selecting a candidate base station installation location to be used in the subsequent visibility determination process based on three-dimensional point cloud data when the proportion of representative points that have been subject to visibility determination based on point cloud data among the representative points that have been determined to have visibility between at least one of the candidate base station installation locations by the visibility determination based on map information reaches a predetermined proportion.

The process flow for area maximization will be described below. Figure 4 is a flowchart showing the operation of station placement and area design support device 1 in area maximization in the first embodiment of the present invention. The operation of station placement and area design support device 1 shown in the flowchart of Figure 4 is a detailed version of the operation of step S14 shown in Figure 2 above.

In the case of processing for improving capacity efficiency, the operation of station placement and area design support device 1 shown in the flowchart in Figure 4 is omitted. The case of processing for improving capacity efficiency corresponds to the case where the branch at step S13 in Figure 2 is NO, and in this case, it can be seen that the operation of step S14 is omitted.

As shown in FIG. 4, the processes from step S142 to step S144 are repeated a number of times corresponding to the number of combinations for which visibility is determined to be present based on the map information (step S141).

First, the map visibility determination unit 41 checks whether there are multiple candidate installation locations for a base station that have been determined to have visibility for a certain representative point among the representative points included in the combination of the candidate installation locations for the base station that have been determined to have visibility based on the visibility determination based on map information and the representative points of the mesh (step S142).

If there are multiple candidate base station installation locations that are determined to have visibility for a certain representative point (step S142, YES), the map visibility determination unit 41 does not perform the subsequent processing of steps S143 and S144, but performs the above-mentioned processing of step S142 for the next representative point.

On the other hand, if there is only one candidate base station installation location that is determined to have line of sight to a certain representative point (step S142, NO), the 3D line of sight determination unit 42 performs line of sight determination processing based on the point cloud data between the representative point, the only candidate base station installation location that is determined to have line of sight to the representative point, and the base station (step S143).

Next, the three-dimensional visibility determination unit 42 records the result of the visibility determination based on the point cloud data by updating the determination feasibility list 304 stored in the storage unit 30 (step S144). The three-dimensional visibility determination unit 42 may delete the combination of the base station installation candidate location and the representative point for which the result of the visibility determination based on the point cloud data has been recorded from the list of combinations that have been determined to have visibility by the visibility determination based on the map information.

Then, when the processing of steps S142 to S144 is repeated a number of times corresponding to the number of combinations of candidate base station installation locations and representative points that are determined to have visibility based on the map information, the operation of the station placement/area design support device 1 shown in the flowchart of Figure 4 is terminated.

Below, we will explain an example of updating the determination feasibility list 304 when performing station placement and area design to maximize area. Figures 5 to 11 are figures showing an example of updating the determination feasibility list 304 when performing station placement and area design to maximize area.

Below, we will explain using the candidate base station installation locations and the visibility assessment results for each mesh within the evaluation area illustrated in Figure 3 above.

Figure 5 shows a list of combinations of base station installation candidate locations and representative points that have been determined to have line of sight by a line of sight determination based on map information. As shown in Figures 3 and 5, the representative points that have been determined to have line of sight to base station installation candidate location A by a line of sight determination based on map information are the six representative points marked with the symbols (1), (2), (3), (4), (5), and (6). The representative points that have been determined to have line of sight to base station installation candidate location B by a line of sight determination based on map information are the five representative points marked with the symbols (2), (3), (4), (5), and (7). The representative points that have been determined to have line of sight to base station installation candidate location C by a line of sight determination based on map information are the four representative points marked with the symbols (6), (8), (10), and (12). Furthermore, the representative points determined to have line of sight to base station installation candidate location D through a visibility assessment based on map information are the five representative points marked with the symbols (8), (9), (10), (11), and (13). Furthermore, the representative points determined to have line of sight to base station installation candidate location E through a visibility assessment based on map information are the two representative points marked with the symbols (13) and (14).

As mentioned above, when performing station placement and area design to maximize coverage, the map visibility determination unit 41 identifies representative points that have been determined to have visibility to only one candidate base station installation location among representative points that have been determined to have visibility to at least one candidate base station installation location based on the visibility determination based on map information.

In the example shown in Figure 3, the representative points that were determined to have line of sight between only one candidate base station installation location based on the visibility assessment based on map information are the representative points marked with the symbols (1), (7), (9), (11), (12), and (14).

The map visibility determination unit 41 records in a list the combinations of these six representative points and the base station installation candidate locations that have been determined to have visibility (by a visibility determination based on map information) with each representative point. The 3D visibility determination unit 42 then performs visibility determination based on point cloud data for the combinations of base station installation candidate locations and representative points that have been added to the list. The 3D visibility determination unit 42 records in a list the results of the visibility determination based on the point cloud data.

Figure 6 shows a list of representative points that have been determined to have line of sight between only one candidate base station installation location and each of the combinations of representative points and candidate base station installation locations that have been determined to have line of sight (based on a line of sight determination based on map information) in a station placement/area design that aims to maximize coverage.

As shown in FIG. 6, in station placement and area design aimed at maximizing coverage area, the list first records the combination of the representative point marked with (1) and candidate location A for base station installation, the combination of the representative point marked with (7) and candidate location B for base station installation, the combination of the representative point marked with (9) and candidate location D for base station installation, the combination of the representative point marked with (11) and candidate location D for base station installation, the combination of the representative point marked with (12) and candidate location C for base station installation, and the combination of the representative point marked with (14) and candidate location E for base station installation.

Furthermore, the list illustrated in FIG. 6 shows the results of the visibility assessment based on the point cloud data for the above combinations. As shown in FIG. 6, the results of the visibility assessment based on the point cloud data for the combination of the representative point marked with the symbol (1) and the base station installation candidate location A, the combination of the representative point marked with the symbol (9) and the base station installation candidate location D, and the combination of the representative point marked with the symbol (11) and the base station installation candidate location D are "visible". On the other hand, the results of the visibility assessment based on the point cloud data for the combination of the representative point marked with the symbol (7) and the base station installation candidate location B, the combination of the representative point marked with the symbol (12) and the base station installation candidate location C, and the combination of the representative point marked with the symbol (14) and the base station installation candidate location E are "not visible".

The map visibility determination unit 41 deletes a combination of a base station installation candidate location and a representative point for which visibility determination based on point cloud data has been completed from the list of combinations of base station installation candidate locations and representative points for which visibility has been determined to be available by visibility determination based on the map information shown in Figure 5 described above.

Figure 7 shows a list of combinations of base station installation candidate locations and representative points that have been determined to have visibility by a visibility determination based on map information, after combinations of base station installation candidate locations and representative points for which visibility determination based on point cloud data has been completed have been deleted. In other words, the list shown in Figure 5 is updated to the list shown in Figure 7.

As shown in FIG. 7, in the updated list, the representative points marked with the symbols (1), (7), (9), (11), (12), and (14) that were determined to have line-of-sight with only one base station installation candidate location based on the line-of-sight judgment based on the map information have been deleted. In the updated list, the representative points that were determined to have line-of-sight with base station installation candidate location A based on the line-of-sight judgment based on the map information are the five representative points marked with the symbols (2), (3), (4), (5), and (6). The representative points that were determined to have line-of-sight with base station installation candidate location B based on the line-of-sight judgment based on the map information are the four representative points marked with the symbols (2), (3), (4), and (5). The representative points that were determined to have line-of-sight with base station installation candidate location C based on the line-of-sight judgment based on the map information are the three representative points marked with the symbols (6), (8), and (10). The representative points determined to have line of sight to base station installation candidate location D through a visibility determination based on map information are the three representative points marked with the symbols (8), (10), and (13), respectively. The representative point determined to have line of sight to base station installation candidate location E through a visibility determination based on map information is the single representative point marked with the symbol (13).

As mentioned above, in station placement and area design that aims to maximize coverage area, the map visibility determination unit 41 first identifies a representative point that is determined to have visibility between only one candidate base station installation location by a visibility determination based on map information, as described above. The 3D visibility determination unit 42 performs visibility determination processing based on point cloud data between the candidate base station installation location and the identified representative point. Thereafter, the map visibility determination unit 41 selects candidate base station installation locations in order starting with the one that has the most representative points that are determined to have visibility by a visibility determination based on map information.

The three-dimensional visibility assessment unit 42 performs visibility assessment processing based on point cloud data between the selected base station installation candidate location and a representative point that has been determined to have visibility between the base station installation candidate location (by visibility assessment based on map information).

As shown in Figure 7, the base station installation candidate location that has the most representative points that are determined to have visibility based on the visibility judgment based on the map information is base station installation candidate location A, which is determined to have visibility to five representative points. Therefore, the map visibility judgment unit 41 selects base station installation candidate location A.

The map visibility assessment unit 41 adds information indicating the combination of the selected base station installation candidate location A and the above five representative points to the list shown in Figure 6. The three-dimensional visibility assessment unit 42 then performs visibility assessment based on point cloud data for the combination of the base station installation candidate location and the representative point added to the list. The three-dimensional visibility assessment unit 42 records the result of the visibility assessment based on the point cloud data in the list.

Figure 8 shows a list to which information indicating the combination of base station installation candidate location A with the above-mentioned five representative points, and information indicating the results of visibility assessment based on the point cloud data for each combination have been newly added.

As shown in Figure 8, the results of the line of sight assessment based on the point cloud data for the newly added combination of the representative point marked with (2) and base station installation candidate location A, the combination of the representative point marked with (3) and base station installation candidate location A, the combination of the representative point marked with (5) and base station installation candidate location A, and the combination of the representative point marked with (6) and base station installation candidate location A are "line of sight." On the other hand, the result of the line of sight assessment based on the point cloud data for the combination of the representative point marked with (4) and base station installation candidate location A is "no line of sight."

The map visibility determination unit 41 deletes the combination of base station installation candidate location A and each representative point for which visibility determination based on point cloud data has been completed from the list of combinations of base station installation candidate locations and representative points that have been determined to have visibility by visibility determination based on the map information shown in Figure 7 described above.

Figure 9 shows a list of combinations of base station installation candidate locations and representative points that have been determined to have visibility by a visibility determination based on map information, after the combination of base station installation candidate location A and representative point for which visibility determination based on point cloud data has been completed has been deleted. In other words, the list shown in Figure 7 is updated to the list shown in Figure 9.

As shown in FIG. 9, the combination of base station installation candidate location A and representative point has been deleted from the updated list. Also, in the updated list, the representative points marked with the symbols (2), (3), (4), (5), and (6) that were determined to have line-of-sight with base station installation candidate location A based on the line-of-sight determination based on map information have been deleted. As a result, in the updated list, all representative points that were determined to have line-of-sight with base station installation candidate location B based on the line-of-sight determination based on map information have disappeared. Also, the representative points that were determined to have line-of-sight with base station installation candidate location C based on the line-of-sight determination based on map information are the two representative points marked with the symbols (8) and (10), respectively. Also, the representative points that were determined to have line-of-sight with base station installation candidate location D based on the line-of-sight determination based on map information remain the three representative points marked with the symbols (8), (10), and (13), respectively. Furthermore, the representative point that has been determined to have visibility to base station installation candidate location E through the visibility determination based on map information remains the single representative point marked with the symbol (13).

As shown in Figure 9, the base station installation candidate location that has the most representative points that are determined to have visibility based on the visibility judgment based on the map information is base station installation candidate location D, which is determined to have visibility to three representative points. Therefore, next, the map visibility judgment unit 41 selects base station installation candidate location D.

The map visibility determination unit 41 adds information indicating the combination of the selected base station installation candidate location D and the above three representative points to the list shown in Figure 8. The three-dimensional visibility determination unit 42 then performs visibility determination based on point cloud data for the combination of the base station installation candidate location and representative point added to the list. The three-dimensional visibility determination unit 42 records the result of the visibility determination based on the point cloud data in the list.

Figure 10 shows a list to which information indicating the combination of base station installation candidate location D with the above three representative points, and information indicating the results of visibility assessment based on the point cloud data for each combination, have been newly added.

As shown in FIG. 10, the results of the visibility assessment based on the point cloud data for the newly added combination of the representative point marked (8) and the candidate location D for the base station, the combination of the representative point marked (10) and the candidate location D for the base station, and the combination of the representative point marked (13) and the candidate location D for the base station, are “visibility available.”

The map visibility determination unit 41 deletes the combination of the base station installation candidate location D and each representative point for which visibility determination based on point cloud data has been completed from the list of combinations of base station installation candidate locations and representative points for which visibility has been determined to be available by visibility determination based on the map information shown in Figure 9 described above.

Figure 11 shows a list of combinations of base station installation candidate locations and representative points that have been determined to have visibility by a visibility determination based on map information, after the combination of base station installation candidate location D and representative point for which visibility determination based on point cloud data has been completed has been deleted. That is, the list shown in Figure 9 is updated to the list shown in Figure 11.

As shown in FIG. 11, the combination of base station installation candidate location D and representative point has been deleted from the updated list. Also, the updated list has deleted the representative points marked with the symbols (8), (10), and (13) that were determined to have line of sight to base station installation candidate location D based on a line of sight determination based on map information. As a result, in the updated list, all representative points that were determined to have line of sight to base station installation candidate location C based on a line of sight determination based on map information have been deleted. Similarly, all representative points that were determined to have line of sight to base station installation candidate location E based on a line of sight determination based on map information have been deleted.

As shown in Figure 11, all combinations of base station installation candidate locations and representative points have been deleted from the updated list. In other words, visibility determination processing based on point cloud data has been performed on all representative points that have been determined to have visibility between at least one base station candidate location based on visibility determination based on map information.

In this way, when station placement/area design is performed to maximize coverage in the evaluation area illustrated in Figure 3, by installing base stations at all of the candidate base station installation locations A to E, station placement/area design result information 305 is obtained, which indicates that the communication area for terminal stations can be a mesh range having ten representative points, each of which has the symbols (1), (2), (3), (5), (6), (8), (9), (10), (11), and (13), as shown in Figure 10.

Up to this point, we have given specific examples of station placement and area design aimed at maximizing coverage in Figures 5 to 11, and shown an example of a situation in which visibility assessment using three-dimensional point cloud data has been performed for some combinations of base station candidate positions and representative points (Figures 6, 8, and 10). However, in the speed-priority visibility assessment (step S16) and accuracy-priority visibility assessment (step S17) in the flowchart shown in Figure 2 above, visibility assessment using three-dimensional point cloud data can also be performed for all combinations. In this case, it is possible to deal with the situation even if the columns for visibility assessment results based on three-dimensional point cloud data in Figures 6, 8, and 10 are eliminated (with only visibility assessment based on map information).

Below, we will explain an example of updating the determination feasibility list 304 when performing station placement/area design to improve accommodation efficiency. Figures 12 to 17 are figures showing an example of updating the determination feasibility list 304 when performing station placement/area design to improve accommodation efficiency.

Below, we will explain using the candidate base station installation locations and the visibility assessment results for each mesh within the evaluation area illustrated in Figure 3 above.

As mentioned above, FIG. 5 shows a list of combinations of base station installation candidate locations and representative points that have been determined to have line of sight by a line of sight determination based on map information. In station placement/area design aimed at improving accommodation efficiency, the map line of sight determination unit 41 selects base station installation candidate locations in order starting from the one that has the most representative points that have been determined to have line of sight by a line of sight determination based on map information. The three-dimensional line of sight determination unit 42 performs line of sight determination processing based on point cloud data between the selected base station installation candidate location and the representative points that have been determined to have line of sight between the base station installation candidate location (by a line of sight determination based on map information).

Then, when the proportion of representative points selected as targets for line of sight determination based on point cloud data among the representative points that have been determined to have line of sight to at least one candidate base station installation location by the line of sight determination based on map information reaches a predetermined proportion, the map visibility determination unit 41 terminates the above process of selecting a candidate base station installation location to be used in the subsequent line of sight determination process based on three-dimensional point cloud data.

As shown in Figure 5, the base station installation candidate location that has the most representative points that are determined to have visibility based on the map information is base station installation candidate location A, which is determined to have visibility to six representative points. Therefore, the map visibility determination unit 41 selects base station installation candidate location A.

The map visibility assessment unit 41 records in a list information indicating the combination of base station installation candidate location A and the six representative points. The three-dimensional visibility assessment unit 42 then performs visibility assessment based on point cloud data for the combination of the base station installation candidate location and the representative point recorded in the list. The three-dimensional visibility assessment unit 42 records the results of the visibility assessment based on the point cloud data in a list.

Figure 12 shows a list that records information indicating the combination of base station installation candidate location A and the above six representative points, as well as information indicating the results of visibility assessment based on the point cloud data for each combination.

As shown in FIG. 12, the results of the line of sight determination based on the point cloud data for the combination of the representative point marked with (1) and the base station installation candidate location A, the combination of the representative point marked with (2) and the base station installation candidate location A, the combination of the representative point marked with (3) and the base station installation candidate location A, the combination of the representative point marked with (5) and the base station installation candidate location A, and the combination of the representative point marked with (6) and the base station installation candidate location A are "line of sight". On the other hand, the result of the line of sight determination based on the point cloud data for the combination of the representative point marked with (4) and the base station installation candidate location A is "no line of sight".

The map visibility determination unit 41 deletes the combination of base station installation candidate location A and each representative point for which visibility determination based on point cloud data has been completed from the list of combinations of base station installation candidate locations and representative points that have been determined to have visibility by visibility determination based on the map information shown in Figure 5 described above.

Figure 13 shows a list of combinations of base station installation candidate locations and representative points that have been determined to have visibility by a visibility determination based on map information, after the combination of base station installation candidate location A and representative point for which visibility determination based on point cloud data has been completed has been deleted. That is, the list shown in Figure 5 is updated to the list shown in Figure 13.

As shown in FIG. 13, the combination of base station installation candidate location A and representative point is deleted from the updated list. Also, in the updated list, the representative points marked with the symbols (1), (2), (3), (4), (5), and (6) that are determined to have line of sight to base station installation candidate location A by the line of sight determination based on map information are deleted. As a result, in the updated list, the representative point that is determined to have line of sight to base station installation candidate location B by the line of sight determination based on map information is the one marked with the symbol (7). Also, the representative points that are determined to have line of sight to base station installation candidate location C by the line of sight determination based on map information are the three marked with the symbols (8), (10), and (12). Also, the representative points that are determined to have line of sight to base station installation candidate location D by the line of sight determination based on map information remain the five marked with the symbols (8), (9), (10), (11), and (13). Furthermore, the representative points that have been determined to have visibility to base station installation candidate location E through a visibility determination based on map information remain the two representative points marked with the symbols (13) and (14), respectively.

As shown in Figure 13, the base station installation candidate location that has the most representative points that are determined to have visibility based on the visibility judgment based on map information is base station installation candidate location D, which is determined to have visibility to five representative points. Therefore, the map visibility judgment unit 41 selects base station installation candidate location D.

The map visibility assessment unit 41 adds information indicating the combination of the selected base station installation candidate location D and the above five representative points to the list shown in Figure 12. The three-dimensional visibility assessment unit 42 then performs visibility assessment based on point cloud data for the combination of the base station installation candidate location and the representative point added to the list. The three-dimensional visibility assessment unit 42 records the result of the visibility assessment based on the point cloud data in the list.

Figure 14 shows a list to which information indicating combinations of base station installation candidate locations D with the above-mentioned five representative points, and information indicating the results of visibility assessments based on the point cloud data for each combination, have been newly added.

As shown in FIG. 14, the results of the visibility assessment based on the point cloud data for the newly added combination of the representative point marked with (8) and candidate location D for the base station, the combination of the representative point marked with (9) and candidate location D for the base station, the combination of the representative point marked with (10) and candidate location D for the base station, the combination of the representative point marked with (11) and candidate location D for the base station, and the combination of the representative point marked with (13) and candidate location D for the base station, are “visibility available.”

The map visibility determination unit 41 deletes the combination of the base station installation candidate location D and each representative point for which visibility determination based on the point cloud data has been completed from the list of combinations of the base station installation candidate locations and representative points for which visibility has been determined to be available by the visibility determination based on the map information shown in Figure 13 described above.

Figure 15 shows a list of combinations of base station installation candidate locations and representative points that have been determined to have visibility by a visibility determination based on map information, after the combination of base station installation candidate location D and representative point for which visibility determination based on point cloud data has been completed has been deleted. In other words, the list shown in Figure 13 is updated to the list shown in Figure 15.

As shown in FIG. 15, the combination of base station installation candidate location D and representative point has been deleted from the updated list. Also, in the updated list, the representative points marked with the symbols (8), (9), (10), (11), and (13) that were determined to have line-of-sight with base station installation candidate location D based on the line-of-sight determination based on map information have been deleted. As a result, in the updated list, the representative point that was determined to have line-of-sight with base station installation candidate location B based on the line-of-sight determination based on map information is the single representative point marked with the symbol (7). Also, the representative point that was determined to have line-of-sight with base station installation candidate location C based on the line-of-sight determination based on map information is the single representative point marked with the symbol (12). The representative point that was determined to have line-of-sight with base station installation candidate location E based on the line-of-sight determination based on map information is the single representative point marked with the symbol (14).

As shown in FIG. 15, the base station installation candidate locations having the most representative points that are determined to have visibility by a visibility determination based on map information are base station installation candidate locations B, C, and E, which are all determined to have visibility to one representative point. Therefore, the map visibility determination unit 41 arbitrarily selects one of the base station installation candidate locations. Here, it is assumed that the map visibility determination unit 41 selects base station installation candidate location B. Note that the map visibility determination unit 41 may also select base station installation candidate location C or E.

The map visibility determination unit 41 adds information indicating the combination of the selected base station installation candidate location B and the one representative point to the list shown in FIG. 14. The three-dimensional visibility determination unit 42 then performs visibility determination based on point cloud data for the combination of the base station installation candidate location and the representative point added to the list. The three-dimensional visibility determination unit 42 records the result of the visibility determination based on the point cloud data in the list.

Figure 16 shows a list to which information indicating the combination of base station installation candidate location B and the above-mentioned one representative point, and information indicating the result of visibility assessment based on the point cloud data for each combination have been newly added.

As shown in Figure 16, the result of the visibility assessment based on the point cloud data for the combination of the newly added representative point marked (7) and base station installation candidate location B is “no visibility.”

The map visibility determination unit 41 deletes the combination of base station installation candidate location B, for which visibility determination based on point cloud data has been completed, and the representative point marked with the symbol (7) from the list of combinations of base station installation candidate locations and representative points that have been determined to have visibility by visibility determination based on the map information shown in Figure 15 described above.

Figure 17 shows a list of combinations of base station installation candidate locations and representative points that have been determined to have visibility by a visibility determination based on map information, after the combination of base station installation candidate location B, for which visibility determination based on point cloud data has been completed, and the representative point marked with the symbol (7) has been deleted. In other words, the list shown in Figure 15 is updated to the list shown in Figure 17.

As shown in FIG. 17, the combination of base station installation candidate location B and the representative point marked with the symbol (7) has been deleted from the updated list. In the updated list, the representative point that has been determined to have line of sight to base station installation candidate location C based on a line of sight determination based on map information remains as the single representative point marked with the symbol (12). Furthermore, the representative point that has been determined to have line of sight to base station installation candidate location E based on a line of sight determination based on map information remains as the single representative point marked with the symbol (14).

At the time when base station installation candidate locations A, D, and B were selected, the representative points for which a line of sight determination based on point cloud data was performed with any of the base station installation candidate locations are the representative points marked with the symbols (1), (2), (3), (4), (5), (6), (7), (8), (9), (10), (11), and (13) as shown in Figure 16, and there are 12 of these representative points. In addition, the total number of representative points for which a line of sight determination based on map information was performed with at least one of all base station installation candidate locations (i.e., base station installation candidate locations A to E) in the evaluation area is 14, as shown in Figure 3.

Therefore, the percentage of the number of representative points for which a visibility determination based on point cloud data has been performed between any of the base station candidate locations A, D, and B and the base station candidate locations out of this total number is approximately 86% (=12/14). If the predetermined percentage is 80%, the above percentage has reached the predetermined percentage, and so the map visibility determination unit 41 ends the above process of selecting the base station candidate locations to be used in the visibility determination process based on three-dimensional point cloud data when the three base station candidate locations A, D, and B have been selected.

In this way, when station placement/area design is performed for the evaluation target area illustrated in Figure 3 to improve capacity efficiency, station placement/area design result information 305 is obtained which indicates that by installing base stations at three base station installation candidate locations A, D, and B, a predetermined percentage of 80% or more of the mesh range including the representative point determined to have visibility by the visibility determination based on map information can be set as the target area for visibility determination based on point cloud data. In other words, compared to when station placement/area design is performed to maximize area, when station placement/area design is performed to improve capacity efficiency, it is possible to make the communication area relatively wide while suppressing an increase in the number of base stations installed.

So far, Figures 12 to 17 have been used to show specific examples of station placement and area design aimed at improving capacity efficiency, with examples being given of situations in which visibility assessment has been carried out using three-dimensional point cloud data for combinations of base station candidate positions and representative points. However, as was mentioned in the explanation of station placement and area design aimed at maximizing area, it is possible to deal with the situation even if there is no visibility assessment result based on the three-dimensional point cloud data in Figures 12, 14, and 16 (using only visibility assessment based on map information). In such cases, visibility assessment based on three-dimensional point cloud data is carried out in later processing in the flowchart of the overall operation of station placement and area design support device 1 (Figure 2).

Below, the visibility determination process of step S143 in the flowchart shown in Figure 4 will be explained in more detail. Figure 18 is a flowchart showing an example of the operation of the visibility determination process of the station placement and area design support device 1 in the first embodiment of the present invention.

First, the 3D visibility assessment unit 42 acquires the number of point cloud data pieces acquired between the representative point and the candidate base station installation location that is to be subject to visibility assessment based on the point cloud data (step S1431).

If the number of point cloud data acquired in step S1431 is less than or equal to a predetermined threshold (step S1432: YES), it is assumed that there are no obstructions between the candidate base station installation location and the representative point, and the 3D visibility assessment unit 42 determines the result of the visibility assessment based on the point cloud data to be "visibility available" (step S1436).

On the other hand, if the number of point cloud data acquired in step S1431 is greater than the predetermined threshold (step S1432, NO), the 3D visibility assessment unit 42 performs a visibility assessment between the candidate base station installation location and the representative point, further taking into account the shielding rate (step S1433).

The visibility assessment that takes the shielding rate into consideration here refers to, for example, a case where a base station is installed at a base station candidate position and a mobile station exists at a representative point, and the visibility assessment is based on the shielding rate of the Fresnel zone formed between the two stations. The method of calculating the shielding rate of the Fresnel zone will be described later.

If the obscuration rate calculated in the visibility judgment taking into account the obscuration rate in step S1434 is equal to or lower than a predetermined threshold value (step S1434: YES), it is considered that there are few (or small) obstructions between the candidate base station installation location and the representative point, and the 3D visibility judgment unit 42 determines the result of the visibility judgment based on the point cloud data to be "visibility available" (step S1436).

On the other hand, if the occlusion rate calculated in the visibility judgment taking the occlusion rate into account in step S1433 is higher than the predetermined threshold (step S1434: NO), the 3D visibility judgment unit 42 determines the result of the visibility judgment based on the point cloud data to be "no visibility" (step S1435). This ends the operation of the station location and area design support device 1 shown in the flowchart of FIG. 18.

In this embodiment, visibility is determined using three-dimensional point cloud data collected by an MMS or the like, but this is not limited to this. Other data indicating the location of obstructions may be used as long as the data contains more information than map information. In this case, visibility can be determined taking into account the obstruction rate even with city data that does not contain the driving trajectory of MMS vehicles, etc.

[How to calculate the shielding rate of the Fresnel zone]
An example of a method for calculating the shielding rate of the Fresnel zone will be described below. The three-dimensional visibility determination unit 42 uses the point cloud data 303 to calculate the shielding rate of the Fresnel zone formed between the base station and the terminal station (i.e., when the Fresnel zone is formed between the base station installation candidate position and the representative point of each mesh), and determines whether communication is possible. For example, the three-dimensional visibility determination unit 42 determines that communication is impossible if the shielding rate is higher than a predetermined threshold, and determines that communication is possible if the shielding rate is equal to or lower than the predetermined threshold.

Actual electromagnetic waves do not propagate only along a straight line between two opposing wireless stations, but also within an elliptical path area called a Fresnel zone. Therefore, in order to more accurately determine whether or not there is line of sight between two opposing wireless stations, it is necessary to determine whether or not there is line of sight while taking into account the effects of obstructions present within the Fresnel zone. The Fresnel zone radius of the millimeter wave band is a maximum of about 25 cm when transmitting a distance of 50 m using electromagnetic waves in the 60 GHz band, for example.

Even if there is no line of sight between the base station installation candidate location and the representative point, the presence or absence of line of sight can be determined by taking into account the shielding rate of the Fresnel zone, making it possible to perform a more accurate line of sight determination. This allows the station location and area design support device 1 to present a wider communication area.

FIG. 19 is a diagram showing the state of determining whether communication is possible or not taking into consideration the Fresnel zone fz. FIG. 19 shows a base station bs and a terminal station ts installed on a utility pole p. FIG. 19 also shows the Fresnel zone fz formed between the base station bs and the terminal station ts. FIG. 19 also shows three cross sections (cross sections cs1, cs2, and cs3) of the Fresnel zone fz. The cross sections cs1, cs2, and cs3 are planes perpendicular to the straight line connecting the base station bs and the terminal station ts. In this case, as shown in FIG. 19, the shapes of the cross sections cs1, cs2, and cs3 are circular. The radii of the cross sections cs1, cs2, and cs3 are r ₁ , r ₂ , and r ₃ , respectively.

If an obstruction is present within the Fresnel zone fz, point cloud data is present on the cross section of the Fresnel zone fz. For example, as shown in FIG. 19, cross section cs1 contains area sh1-1, which is an area of point cloud data. Cross section cs2 contains area sh1-2 onto which the aforementioned area sh1-1 is projected, and area sh2-2, which is an area of point cloud data. Cross section cs3 contains area sh1-3 onto which the aforementioned area sh1-2 is further projected, area sh2-3 onto which the aforementioned area sh2-2 is further projected, and area sh3-3, which is an area of point cloud data.

In view of the above, within the range of the Fresnel zone fz shown in Fig. 19, there may be obstructions that can block the propagation of radio waves, such as buildings (architectures) such as dwellings and buildings, structures such as residential fences and elevated roads, structures such as road signs and billboards, plants such as roadside trees and garden trees, and raised ground. Note that although the terminal station ts is installed in a building in Fig. 19, the same applies even if the terminal station is a mobile terminal as in this embodiment.

The three-dimensional visibility determination unit 42, for example, superimposes multiple cross sections of the Fresnel zone fz. The three-dimensional visibility determination unit 42 then calculates the proportion of the area of the superimposed cross sections that is indicated by the area of the point cloud data as the shading rate. The three-dimensional visibility determination unit 42 compares the calculated shading rate with a predetermined threshold value to determine whether communication between the base station bs and the terminal station ts is possible. Alternatively, the three-dimensional visibility determination unit 42 determines whether communication between the base station bs and the terminal station ts is possible by determining whether there is visibility between the base station bs and the terminal station ts based on the superimposed cross sections.

As described above, according to the station placement/area design support device 1 in this embodiment, it becomes possible to selectively use station placement/area design that aims to maximize area and station placement/area design that aims to improve capacity efficiency.

The station location and area design support device 1 in this embodiment can be applied to station location design for wireless communication systems (particularly mobile communication systems) that mainly use millimeter waves to cover urban areas as their service areas. Conventional millimeter wave band station location design methods take into account the characteristics of the millimeter wave band, which suffers from severe distance attenuation and shielding attenuation, and generally adopt the approach of installing base stations at locations where communication can be established in urban areas.

However, the needs of the operators and users who install base stations are not uniform. There are two methods to consider: area maximization, which is a method of station placement and area design that maximizes the area that can accommodate terminal stations, and accommodation efficiency, which is an efficient station placement and area design that uses a smaller number of base stations while achieving a relatively large area that can accommodate terminal stations.

For example, in urban areas there is a need to maximize the area that can accommodate terminal stations, while in suburban and rural areas there is a need to have a relatively large area that can accommodate terminal stations while using a smaller number of base stations. Although these two types of needs are similar, strictly speaking, the station placement results that should be obtained may differ. Therefore, if a station placement and area design method that differs from the needs is used, it will not meet the needs of the operators and users who are the entities that install the base stations.

As shown in Figures 3 and 4, in this embodiment, when performing station location/area design that aims to maximize area, the station location/area design support device 1 prioritizes the process of "identifying a representative point that is determined to have line of sight to only one candidate base station installation location through a line of sight determination based on map information, and subjecting the combination of that candidate base station installation location and that representative point to subsequent line of sight determination processing based on three-dimensional point cloud data," and omits this process when performing station location/area design that aims to improve capacity efficiency. With just a minor algorithm switch, station location/area design can be performed to meet user needs.

[Visibility determination process by each processing mode]
The visibility determination process in each processing mode will be described in detail below. As described above, the processing modes include a "visibility determination prioritizing reduction in processing load" processing mode and a "visibility determination prioritizing accuracy" processing mode, as shown in steps S16 and S17 of the flowchart in FIG. 2, for example.

First, the flow of visibility determination processing with priority given to reducing the processing load will be described. Figure 20 is a flowchart showing the operation of station location and area design support device 1 in a visibility determination with priority given to reducing the processing load in the first embodiment of the present invention. The operation of station location and area design support device 1 shown in the flowchart of Figure 20 is a detailed version of the operation of step S16 shown in Figure 2 above.

As shown in FIG. 20, the loop processing from step S162 to step S163 is repeated a number of times corresponding to the number of candidate base station installation locations (step S161).

First, the map visibility determination unit 41 identifies the base station installation candidate location that has the largest number of representative points that are determined to have visibility based on the map information (step S162).

20, the processes from step S164 to step S166 are repeated a number of times corresponding to the number of representative points (step S163). That is, the loop process of step S163 is repeated for each of the base station installation candidate locations.

Next, the 3D visibility determination unit 42 performs visibility determination processing based on the point cloud data between the base station installation candidate location and the representative point (step S164). Note that the processing in step S164 corresponds to the visibility determination processing of the station placement and area design support device 1 shown in FIG. 18, for example.

Next, the three-dimensional visibility determination unit 42 records the result of the visibility determination based on the point cloud data by updating the determination feasibility list 304 stored in the storage unit 30 (step S165). The three-dimensional visibility determination unit 42 also deletes the combination of the base station installation candidate location and the representative point for which the result of the visibility determination based on the point cloud data has been recorded from the list of combinations that have been determined to have visibility by the visibility determination based on the map information.

Next, the map visibility determination unit 41 determines whether the proportion of representative points that have been determined to have visibility by the visibility determination based on map information and that have also been subjected to a visibility determination based on point cloud data is equal to or greater than a predetermined threshold (step S166). Note that in the visibility determination process that prioritizes reduction in processing load, the map visibility determination unit 41 does not take into account whether the result of the visibility determination based on point cloud data was "visible" or "not visible" when determining the above proportion to be compared with the above threshold (unlike the visibility determination process that prioritizes accuracy, which will be described later).

If the proportion of representative points for which a visibility assessment based on map information has been performed and for which a visibility assessment based on point cloud data has also been performed is less than a predetermined threshold (step S166: NO), the process returns to step S163 or step S161, and the 3D visibility assessment unit 42 further performs visibility assessment based on point cloud data for other candidate base station installation locations and other representative points.

On the other hand, if the proportion of representative points for which a visibility determination based on point cloud data has also been performed among the representative points for which a visibility determination based on map information has been performed is equal to or greater than a predetermined threshold (step S166: YES), the map visibility determination unit 41 ends the visibility determination process that prioritizes reducing the processing load. This ends the operation of the station location and area design support device 1 shown in the flowchart of Figure 20.

Note that, when visibility assessment is performed for each base station installation candidate location and mesh within the evaluation target area exemplified in Figure 3 described above, if area maximization is specified, the judgment feasibility list 304 updated by the above-mentioned visibility assessment process that prioritizes reducing processing load will be as shown in Figures 5 to 11. However, when the proportion of representative points that have been determined to have visibility by a visibility assessment based on map information and that have also been subjected to a visibility assessment based on point cloud data reaches or exceeds a predetermined threshold, the updating of the judgment feasibility list 304 ends.

Furthermore, in the case where visibility assessment is performed for each base station installation candidate location and mesh within the evaluation area exemplified in Figure 3 described above, if accommodation efficiency is specified, the judgment feasibility list 304 updated by the above-mentioned visibility assessment process that prioritizes reduction in processing load will be as shown in Figures 5 and 12 to 17. However, when the proportion of representative points that have been determined to have visibility by a visibility assessment based on map information and that have also been subjected to a visibility assessment based on point cloud data reaches or exceeds a predetermined threshold, the updating of the judgment feasibility list 304 ends.

Next, the flow of the accuracy-priority visibility determination process will be described. Figure 21 is a flowchart showing the operation of the station location and area design support device 1 in the first embodiment of the present invention in an accuracy-priority visibility determination. The operation of the station location and area design support device 1 shown in the flowchart of Figure 21 is a detailed version of the operation of step S17 shown in Figure 2 above.

As shown in FIG. 21, the loop processing from step S172 to step S173 (i.e., steps S174 to S177) is repeated a number of times corresponding to the number of candidate base station installation locations (step S171).

First, the map visibility determination unit 41 identifies the base station installation candidate location that has the largest number of representative points that are determined to have visibility based on the map information (step S172).

21, the processes from step S174 to step S177 are repeated a number of times corresponding to the number of representative points (step S173). That is, the loop process of step S173 is repeated for each of the base station installation candidate locations.

Next, the 3D visibility determination unit 42 performs visibility determination processing based on the point cloud data between the base station installation candidate location and the representative point (step S174). Note that the processing in step S174 corresponds to the visibility determination processing of the station placement and area design support device 1 shown in FIG. 18, for example.

In step S174, if the result of the visibility judgment based on the point cloud data is "visibility exists" (step S175, YES), the 3D visibility judgment unit 42 records the judgment result of the visibility judgment based on the point cloud data by updating the judgment feasibility list 304 stored in the memory unit 30 (step S176). In addition, the 3D visibility judgment unit 42 deletes the combination of the base station installation candidate location and the representative point for which the judgment result of the visibility judgment based on the point cloud data is recorded from the list of combinations that are judged to have visibility by the visibility judgment based on the map information.

On the other hand, if in step S174 the result of the visibility assessment based on the point cloud data is “no visibility” (step S175, NO), the 3D visibility assessment unit 42 omits the processing of the above-mentioned step S176.

Next, the map visibility determination unit 41 determines whether the proportion of representative points that have been determined to have visibility by a visibility determination based on map information and that have also been determined to have visibility by a visibility determination based on point cloud data is greater than or equal to a predetermined threshold (step S177).

If the proportion of representative points that are determined to have visibility based on the point cloud data among the representative points that are determined to have visibility based on the map information is less than a predetermined threshold (step S177: NO), the process returns to step S173 or step S171, and the three-dimensional visibility determination unit 42 further performs visibility determination based on the point cloud data for other base station installation candidate locations and other representative points.

On the other hand, if the ratio of representative points that are determined to have visibility by the visibility judgment based on the point cloud data to the representative points that are determined to have visibility by the visibility judgment based on the map information is equal to or greater than a predetermined threshold (step S177: YES), the map visibility judgment unit 41 ends the accuracy-priority visibility judgment process. This ends the operation of the station location and area design support device 1 shown in the flowchart of FIG.

3, if visibility assessment is performed for each base station installation candidate location and mesh in the evaluation target area exemplified above and area maximization is specified, the determination feasibility list 304 updated by the above-mentioned accuracy-priority visibility assessment process will be as follows: However, when the proportion of representative points that are determined to have visibility by the visibility assessment based on point cloud data, among the representative points that are determined to have visibility by the visibility assessment based on map information, reaches or exceeds a predetermined threshold, the updating of the determination feasibility list 304 ends.

In addition, the judgment feasibility list 304 that is updated by the visibility judgment process that prioritizes accuracy when area maximization is specified is the same as the judgment feasibility list 304 that is updated by the visibility judgment process that prioritizes reduction in processing burden when area maximization is specified as described above, as shown in Figures 5 to 7.

Figures 22 to 26 are figures showing an example of updating the judgment feasibility list 304 when performing station placement and area design with a priority on accuracy to maximize area.

Figure 22 shows a list to which newly added information indicating the combination of base station installation candidate location A with the above four representative points, and information indicating the results of visibility assessment based on the point cloud data for each combination, has been added.

As shown in FIG. 22, the results of the visibility assessment based on the point cloud data for the newly added combination of the representative point marked with (2) and candidate location A for the base station, the combination of the representative point marked with (3) and candidate location A for the base station, the combination of the representative point marked with (5) and candidate location A for the base station, and the combination of the representative point marked with (6) and candidate location A for the base station were “visible.”

On the other hand, the result of the visibility assessment based on the point cloud data for the combination of the representative point marked with the code (4) and the candidate base station installation location A has not been added. In other words, this means that the result of the visibility assessment based on the point cloud data for the combination of the representative point marked with the code (4) and the candidate base station installation location A was "no visibility."

The map visibility determination unit 41 deletes representative points included in combinations of candidate base station installation locations A and representative points for which visibility determination based on point cloud data has been completed and the determination result is "visibility available" from the list of combinations of candidate base station installation locations and representative points that have been determined to have visibility by visibility determination based on map information shown in the above-mentioned Figure 7.

Figure 23 shows a list of combinations of base station installation candidate locations and representative points that have been determined to have visibility by a visibility determination based on map information after the combination of base station installation candidate location A for which visibility determination based on point cloud data has been completed and the base station installation candidate location A and the representative point for which visibility has been determined to have been deleted. That is, the list shown in Figure 7 is updated to the list shown in Figure 23.

As shown in FIG. 23, the combination of base station installation candidate location A and representative point has been deleted from the updated list. Also, in the updated list, the representative points marked with the symbols (2), (3), (5), and (6) that were determined to have line-of-sight with base station installation candidate location A based on the line-of-sight determination based on map information have been deleted. As a result, in the updated list, the representative point that was determined to have line-of-sight with base station installation candidate location B based on the line-of-sight determination based on map information is the one marked with the symbol (4). Also, the representative points that were determined to have line-of-sight with base station installation candidate location C based on the line-of-sight determination based on map information are the two marked with the symbols (8) and (10). Also, the representative points that were determined to have line-of-sight with base station installation candidate location D based on the line-of-sight determination based on map information remain the three marked with the symbols (8), (10), and (13). Furthermore, the representative point that has been determined to have visibility to base station installation candidate location E through the visibility determination based on map information remains the single representative point marked with the symbol (13).

The representative point marked with the symbol (4) was determined to have visibility based on map information, but was determined to have no visibility based on point cloud data, so it has been left without being deleted. Therefore, in subsequent processing, there remains a possibility that visibility determination processing based on point cloud data will be performed between base station installation candidate location B and the representative point marked with the symbol (4). In other words, in a visibility determination processing that prioritizes accuracy, visibility determination processing based on point cloud data with respect to multiple base station installation candidate locations may be performed for one representative point. As a result, the accuracy of the visibility determination processing that prioritizes accuracy is improved compared to visibility determination processing that prioritizes reduction in processing burden.

As shown in Figure 23, the base station installation candidate location that has the most representative points that are determined to have visibility based on the map information is base station installation candidate location D, which is determined to have visibility to three representative points. Therefore, next, the map visibility determination unit 41 selects base station installation candidate location D.

The map visibility determination unit 41 adds information indicating the combination of the selected base station installation candidate location D and the above three representative points to the list shown in Figure 22. The three-dimensional visibility determination unit 42 then performs visibility determination based on point cloud data for the combination of the base station installation candidate location and representative point added to the list. The three-dimensional visibility determination unit 42 records the result of the visibility determination based on the point cloud data in the list.

Figure 24 shows a list to which information indicating the combination of base station installation candidate location D with the above three representative points, and information indicating the results of visibility assessment based on the point cloud data for each combination, have been newly added.

As shown in FIG. 24, the results of the visibility assessment based on the point cloud data for the newly added combination of the representative point marked (8) and the candidate location D for the base station, the combination of the representative point marked (10) and the candidate location D for the base station, and the combination of the representative point marked (13) and the candidate location D for the base station, are “visibility available.”

The map visibility determination unit 41 deletes the combination of the base station installation candidate location D and each representative point for which visibility determination based on point cloud data has been completed from the list of combinations of base station installation candidate locations and representative points for which visibility has been determined to be available by visibility determination based on the map information shown in the above-mentioned Figure 23.

Figure 25 shows a list of combinations of base station installation candidate locations and representative points that have been determined to have visibility by a visibility determination based on map information, after the combination of base station installation candidate location D and representative point for which visibility determination based on point cloud data has been completed has been deleted. That is, the list shown in Figure 23 is updated to the list shown in Figure 25.

As shown in FIG. 25, the combination of base station installation candidate location D and representative point has been deleted from the updated list. Also, in the updated list, the representative points marked with symbols (8), (10), and (13) that were determined to have line-of-sight with base station installation candidate location D based on the line-of-sight determination based on map information have been deleted. As a result, in the updated list, the representative point that was determined to have line-of-sight with base station installation candidate location B based on the line-of-sight determination based on map information remains as the single representative point marked with symbol (4). All representative points that were determined to have line-of-sight with base station installation candidate location C have been deleted. Similarly, all representative points that were determined to have line-of-sight with base station installation candidate location E based on the line-of-sight determination based on map information have been deleted.

As shown in Figure 25, the base station installation candidate location that has more representative points that are determined to have visibility based on the map information is base station installation candidate location B, which is determined to have visibility to one representative point. Therefore, next, the map visibility determination unit 41 selects base station installation candidate location B.

The map visibility determination unit 41 adds information indicating the combination of the selected base station installation candidate location B and the one representative point to the list shown in FIG. 24. The three-dimensional visibility determination unit 42 then performs visibility determination based on point cloud data for the combination of the base station installation candidate location and the representative point added to the list. The three-dimensional visibility determination unit 42 records the result of the visibility determination based on the point cloud data in the list.

Figure 26 shows a list to which information indicating the combination of base station installation candidate location B and the above-mentioned one representative point (i.e., the representative point marked with the symbol (4)) and information indicating the result of visibility assessment based on the point cloud data of the combination have been newly added.

As shown in Figure 26, the result of the visibility assessment based on the point cloud data for the combination of the newly added representative point marked (4) and base station installation candidate location B is “visibility available.”

The map visibility determination unit 41 deletes the combination of the base station installation candidate location B and the representative point for which visibility determination based on point cloud data has been completed from the list of combinations of the base station installation candidate locations and the representative point for which visibility has been determined to be available by visibility determination based on map information shown in the above-mentioned Figure 25. After the combination of the base station installation candidate location B and the representative point for which visibility determination based on point cloud data has been completed has been deleted, the list of combinations of the base station installation candidate locations and the representative point for which visibility has been determined to be available by visibility determination based on map information will be the same as the list in the above-mentioned Figure 11.

11, all combinations of base station installation candidate locations and representative points have been deleted from the updated list. That is, the visibility determination process based on point cloud data has been performed on all representative points that have been determined to have visibility between at least one base station candidate location by the visibility determination based on map information. However, when the ratio of representative points that have been determined to have visibility by the visibility determination based on map information and that have also been determined to have visibility by the visibility determination based on point cloud data reaches or exceeds a predetermined threshold, the update of the determination feasibility list 304 ends.

In the case where visibility assessment is performed for each base station installation candidate location and mesh within the evaluation target area exemplified in Figure 3 described above, if area maximization is specified, the determination feasibility list 304 updated by the above-mentioned visibility assessment process that prioritizes reducing processing load will be as follows. However, when the proportion of representative points that are determined to have visibility by a visibility assessment based on map information and that are also determined to have visibility by a visibility assessment based on point cloud data reaches or exceeds a predetermined threshold, the updating of the determination feasibility list 304 ends.

Here, when comparing the results of the station placement and area design that prioritizes reducing the processing burden and aims to maximize the area as described above (Figure 10) with the results of the station placement and area design that prioritizes accuracy and aims to maximize the area as described above (Figure 26), it can be seen that the results of the station placement and area design that prioritizes accuracy (Figure 26), unlike the results of the station placement and area design that prioritizes reducing the processing burden (Figure 10), may select a combination of a candidate base station installation location and a representative point (for example, the representative point marked (4)) that is determined to have line of sight based on a line of sight judgment based on point cloud data.

Figures 27 to 31 are figures showing an example of updating the judgment feasibility list 304 when performing station placement and area design with priority on accuracy to improve accommodation efficiency.

Figure 27 shows a list to which information indicating combinations of base station installation candidate location A and five representative points, and information indicating the results of visibility assessment based on the point cloud data for each combination, have been newly added.

As shown in FIG. 27, the results of the visibility assessment based on the point cloud data for the combination of the representative point marked with (1) and the candidate location A for the base station, the combination of the representative point marked with (2) and the candidate location A for the base station, the combination of the representative point marked with (3) and the candidate location A for the base station, the combination of the representative point marked with (5) and the candidate location A for the base station, and the combination of the representative point marked with (6) and the candidate location A for the base station, were “visible.”

On the other hand, the result of the visibility assessment based on the point cloud data for the combination of the representative point marked with the code (4) and the candidate base station installation location A has not been added. In other words, this means that the result of the visibility assessment based on the point cloud data for the combination of the representative point marked with the code (4) and the candidate base station installation location A was "no visibility."

The map visibility determination unit 41 deletes representative points included in combinations of candidate base station installation locations A and representative points for which visibility determination based on point cloud data has been completed and the determination result is "visibility available" from the list of combinations of candidate base station installation locations and representative points that have been determined to have visibility by visibility determination based on map information shown in the above-mentioned Figure 7.

Figure 28 shows a list of combinations of base station installation candidate locations and representative points that have been determined to have visibility by a visibility determination based on map information after the combination of base station installation candidate location A for which visibility determination based on point cloud data has been completed and the base station installation candidate location A and the representative point for which visibility has been determined to have been deleted. That is, the list shown in Figure 5 is updated to the list shown in Figure 28.

As shown in FIG. 28, the combination of base station installation candidate location A and representative point is deleted from the updated list. Also, in the updated list, the representative points marked with the symbols (2), (3), (5), and (6) that are determined to have line of sight to base station installation candidate location A by the line of sight determination based on map information are deleted. As a result, in the updated list, the representative points that are determined to have line of sight to base station installation candidate location B by the line of sight determination based on map information are the two representative points marked with the symbols (4) and (7). Also, the representative points that are determined to have line of sight to base station installation candidate location C by the line of sight determination based on map information are the three representative points marked with the symbols (8), (10), and (12). Also, the representative points that are determined to have line of sight to base station installation candidate location D by the line of sight determination based on map information remain the five representative points marked with the symbols (8), (9), (10), (11), and (13). Furthermore, the representative points that have been determined to have visibility to base station installation candidate location E through a visibility determination based on map information remain the two representative points marked with the symbols (13) and (14).

The representative point marked with the symbol (4) was determined to have visibility based on map information, but was determined to have no visibility based on point cloud data, so it has been left without being deleted. Therefore, in subsequent processing, there remains a possibility that visibility determination processing based on point cloud data will be performed between base station installation candidate location B and the representative point marked with the symbol (4). In other words, in a visibility determination processing that prioritizes accuracy, visibility determination processing based on point cloud data with respect to multiple base station installation candidate locations may be performed for one representative point. As a result, the accuracy of the visibility determination processing that prioritizes accuracy is improved compared to visibility determination processing that prioritizes reduction in processing burden.

As shown in Figure 28, the base station installation candidate location that has the most representative points that are determined to have visibility based on the map information is base station installation candidate location D, which is determined to have visibility to five representative points. Therefore, next, the map visibility determination unit 41 selects base station installation candidate location D.

The map visibility assessment unit 41 adds information indicating the combination of the selected base station installation candidate location D and the above five representative points to the list shown in Figure 27. The three-dimensional visibility assessment unit 42 then performs visibility assessment based on point cloud data for the combination of the base station installation candidate location and the representative point added to the list. The three-dimensional visibility assessment unit 42 records the result of the visibility assessment based on the point cloud data in the list.

Figure 29 shows a list to which newly added information indicating combinations of base station installation candidate locations D with the above-mentioned five representative points, and information indicating the results of visibility assessment based on the point cloud data for each combination, has been added.

As shown in FIG. 29, the results of the visibility assessment based on the point cloud data for the newly added combination of the representative point marked with (8) and candidate location D for the base station, the combination of the representative point marked with (9) and candidate location D for the base station, the combination of the representative point marked with (10) and candidate location D for the base station, the combination of the representative point marked with (11) and candidate location D for the base station, and the combination of the representative point marked with (13) and candidate location D for the base station, are “visible.”

The map visibility determination unit 41 deletes the combination of the base station installation candidate location D and each representative point for which visibility determination based on point cloud data has been completed from the list of combinations of base station installation candidate locations and representative points for which visibility has been determined to be available by visibility determination based on the map information shown in the above-mentioned Figure 28.

Figure 30 shows a list of combinations of base station installation candidate locations and representative points that have been determined to have visibility by a visibility determination based on map information, after the combination of base station installation candidate location D and representative point for which visibility determination based on point cloud data has been completed has been deleted. That is, the list shown in Figure 28 is updated to the list shown in Figure 30.

As shown in FIG. 30, the combination of base station installation candidate location D and representative point has been deleted from the updated list. Also, in the updated list, the representative points marked with the symbols (8), (9), (10), (11), and (13) that were determined to have line-of-sight with base station installation candidate location D based on the line-of-sight determination based on map information have been deleted. As a result, in the updated list, the representative points that were determined to have line-of-sight with base station installation candidate location B based on the line-of-sight determination based on map information remain the two representative points marked with the symbols (4) and (7). The representative point that was determined to have line-of-sight with base station installation candidate location C is the single representative point marked with the symbol (12). Also, the representative point that was determined to have line-of-sight with base station installation candidate location E based on the line-of-sight determination based on map information is the single representative point marked with the symbol (14).

As shown in Figure 30, the base station installation candidate location that has more representative points that are determined to have visibility based on the map information is base station installation candidate location B, which is determined to have visibility to two representative points. Therefore, next, the map visibility determination unit 41 selects base station installation candidate location B.

The map visibility determination unit 41 adds information indicating the combination of the selected base station installation candidate location B and the above two representative points to the list shown in Figure 29. The 3D visibility determination unit 42 then performs visibility determination based on point cloud data for the combination of the base station installation candidate location and the representative point added to the list. The 3D visibility determination unit 42 records the result of the visibility determination based on the point cloud data in the list.

Figure 31 shows a list to which information indicating the combination of base station installation candidate location B and the above two representative points (i.e., the representative points marked with the symbols (4) and (7)) and information indicating the results of visibility assessment based on the point cloud data of the combination have been newly added.

As shown in Figure 31, the result of the visibility assessment based on the point cloud data for the combination of the newly added representative point marked with (4) and base station installation candidate location B is "visibility available." Also, the result of the visibility assessment based on the point cloud data for the combination of the representative point marked with (7) and base station installation candidate location B is "no visibility."

The map visibility determination unit 41 deletes the combination of the base station installation candidate location B and the representative point for which visibility determination based on point cloud data has been completed from the list of combinations of the base station installation candidate locations and the representative point for which visibility has been determined to be available by visibility determination based on map information shown in the above-mentioned Figure 30. After the combination of the base station installation candidate location B and the representative point for which visibility determination based on point cloud data has been completed has been deleted, the list of combinations of the base station installation candidate locations and the representative point for which visibility has been determined to be available by visibility determination based on map information will be the same as the list in the above-mentioned Figure 17.

In the updated list, the combination of base station installation candidate location B and the representative points marked with the symbols (4) and (7) has been deleted. In the updated list, the representative point that has been determined to have line of sight to base station installation candidate location C based on a line of sight determination based on map information remains the single representative point marked with the symbol (12). Furthermore, the representative point that has been determined to have line of sight to base station installation candidate location E based on a line of sight determination based on map information remains the single representative point marked with the symbol (14).

At the time when base station installation candidate locations A, D, and B were selected, the representative points for which a line of sight determination based on point cloud data was performed with any of the base station installation candidate locations are the representative points marked with the symbols (1), (2), (3), (4), (5), (6), (7), (8), (9), (10), (11), and (13) as shown in Figure 31, and there are 12 of them. In addition, the total number of representative points for which a line of sight determination based on map information was performed with at least one of all base station installation candidate locations (i.e., base station installation candidate locations A to E) in the evaluation area is 14, as shown in Figure 3.

Therefore, the percentage of the number of representative points for which a visibility determination based on point cloud data has been performed between any of the base station candidate locations A, D, and B and the base station candidate locations out of this total number is approximately 86% (=12/14). If the predetermined percentage is 80%, the above percentage has reached the predetermined percentage, and so the map visibility determination unit 41 ends the above process of selecting the base station candidate locations to be used in the visibility determination process based on three-dimensional point cloud data when the three base station candidate locations A, D, and B have been selected.

Here, when comparing the results of the station location and area design that prioritizes reduction in processing burden to improve the aforementioned capacity efficiency (Figure 16) with the results of the station location and area design that prioritizes accuracy to improve capacity efficiency (Figure 31), it can be seen that the results of the station location and area design that prioritizes accuracy (Figure 31) differ from the results of the station location and area design that prioritizes reduction in processing burden (Figure 16) in that there are more combinations of candidate base station installation locations and representative points (for example, representative points marked with (4)) that are determined to have line of sight based on the line of sight judgment based on point cloud data.

As described above, in the visibility determination process that prioritizes reduction in processing load, the map visibility determination unit 41 does not perform visibility determination based on point cloud data between a representative point for which a visibility determination based on point cloud data has been performed between any of the base station installation candidate locations and other base station installation candidate locations. Also, in the visibility determination process that prioritizes reduction in processing load, the map visibility determination unit 41 terminates the visibility determination process based on point cloud data when the proportion of representative points that have been determined to have visibility by a visibility determination based on map information and that have also been subjected to visibility determination based on point cloud data is equal to or greater than a predetermined threshold value.

By having such a configuration, in visibility assessment processing that prioritizes reducing the processing burden, the map visibility assessment unit 41 can further reduce the processing burden in station location and area design processing compared to visibility assessment processing that prioritizes accuracy.

On the other hand, as described above, in the visibility judgment process with priority on accuracy, the map visibility judgment unit 41 performs visibility judgment based on the point cloud data between any of the base station installation candidate locations, and for the representative point whose judgment result is "no visibility", may further perform visibility judgment based on the point cloud data between the representative point and other base station installation candidate locations. That is, in the visibility judgment process with priority on accuracy, visibility judgment process based on the point cloud data between one representative point and multiple base station installation candidate locations may be performed. Also, in the visibility judgment process with priority on accuracy, the map visibility judgment unit 41 further performs visibility judgment based on the point cloud data among the representative points that were judged to have visibility by the visibility judgment based on the map information, and when the proportion of the representative points whose judgment result was "visible" is equal to or greater than a predetermined threshold value, ends the visibility judgment process based on the point cloud data.

By having such a configuration, in visibility assessment processing that prioritizes accuracy, the map visibility assessment unit 41 can achieve higher processing accuracy in station location and area design processing compared to visibility assessment processing that prioritizes reducing processing burden.

Second Embodiment
The second embodiment of the present invention will be described below. In the first embodiment described above, a method for determining the presence or absence of visibility between a base station installation candidate position and a representative point, taking into consideration the shielding rate of the Fresnel zone formed between the two stations, was described with reference to FIG.

As described above, in the first embodiment, the three-dimensional visibility determination unit 42, for example, superimposes multiple cross sections of the Fresnel zone fz. The three-dimensional visibility determination unit 42 then calculates the proportion of the area of the superimposed cross sections that is indicated by the area of the point cloud data as the shading rate. The three-dimensional visibility determination unit 42 is configured to determine whether communication between the base station bs and the terminal station ts is possible by comparing the calculated shading rate with a predetermined threshold value. Alternatively, the three-dimensional visibility determination unit 42 is configured to determine whether communication between the base station bs and the terminal station ts is possible by determining whether there is visibility between the base station bs and the terminal station ts based on the superimposed cross sections.

However, because the Fresnel zone is a spheroid, complex calculations are required to extract the target point cloud data and to overlap multiple circular cross sections of different sizes. In contrast, the station location and area design support device 1 in the second embodiment described below reduces the processing burden of the visibility determination process by regarding the Fresnel zone as a circle, which is a simpler shape.

Generally, when the frequency of radio waves used for wireless communication is high (e.g., millimeter wave band, etc.), the radius of the circular cross section of the Fresnel zone, which is a spheroid, is at most several tens of centimeters, less than 1 meter, even if the communication distance is several hundred meters. Furthermore, even if the object to be measured is located several tens of meters (e.g., 50 meters or more) away from the MMS at a typical driving speed of the MMS vehicle (approximately 50 km/h or more), the measurement interval of the point cloud data is about 10 cm. In this way, it is possible to obtain point cloud data at sufficiently close intervals.

As described above, when considering the Fresnel zone formed in wireless communication using radio waves in the high frequency band, and the measurement interval of point cloud data by MMS, it is believed that sufficient accuracy in determining visibility can be obtained even if a simpler method of acquiring point cloud data and a method of determining visibility are used compared to the first embodiment.

Figure 32 is a schematic diagram showing how visibility is determined by regarding the Fresnel zone as cylindrical. In Figure 32, a base station bs, a mobile station ts (corresponding to a representative point), and a Fresnel zone considered to be cylindrical (hereinafter referred to as "cylindrical Fresnel zone Cz") are shown.

32, the length of the cylindrical Fresnel zone Cz (i.e., the distance between the base station bs and the mobile station ts) is d, and the radius of the circular cross section, which is the vertical cross section of the cylindrical Fresnel zone Cz, is r. Note that the radius r may be a predetermined value, or may be the maximum radius of the circular cross section of the ellipsoid of rotation Fresnel zone that is originally formed between the base station bs and the mobile station ts.

33 is a diagram in which a cylindrical Fresnel zone Cz is superimposed on the Fresnel zone fz. If the distance from the base station bs to the circular cross section of the Fresnel zone fz is d1 and the distance from the mobile station ts to the circular cross section of the Fresnel zone fz is _d1 and _d2 , respectively, then d= _d1 + _d2 can be expressed. In addition, the n-th Fresnel zone radius r(n) is a function of the wavelength λ of the radio wave used in wireless communication, and is expressed by the following formula (1).

Here, the radius r of the cross section at the center (d ₁ =d ₂ ) in the first Fresnel zone, that is, the largest circular cross section, can be expressed by a simpler formula, such as the following formula (2).

The wavelength λ is expressed as a function of the speed of light c (=3.0×10 ⁸ [m]) and the frequency f of the radio wave used in wireless communication, as shown in the following formula (3). Therefore, it is reasonable to change the radius of the cylindrical Fresnel zone Cz depending on the frequency f, such as the millimeter wave band.

In addition, a user using the station placement/area design support device 1 in this embodiment may set the radius r of the circular cross section in the cylindrical Fresnel zone Cz according to the length.

In this way, by regarding the Fresnel zone fz, which is a spheroid, as a cylindrical Fresnel zone Cz as shown in Figure 32, the process of extracting point cloud data (which is a factor that blocks visibility) is greatly simplified.

Furthermore, as shown in Figure 33, the size of the circular cross section varies depending on the location in the Fresnel zone fz, which is a spheroid, so the process of overlapping the occluded parts of these different sized circular cross sections is complicated, but by regarding the Fresnel zone fz as a cylindrical Fresnel zone Cz, the above complicated process can be replaced with a simple process of counting the number of point cloud data present within the cylinder. In other words, using a method of determining whether the number of point cloud data within a cylinder exceeds a threshold value can be a much simpler visibility determination process than using a method of determining whether the area of the occluded parts of the overlapped circular cross sections exceeds a predetermined threshold value.

Third Embodiment
In the visibility assessment described in the first embodiment above, there may be cases where many of the representative points for which there is only one candidate installation location for a base station that has been determined to have visibility based on map information are determined to have no visibility based on a visibility assessment based on point cloud data.

In response to these issues, the station location and area design support device 1 in the third embodiment described below gives up and terminates the process when a certain number (or percentage) of representative points are determined to have no visibility, even if the visibility determination process based on point cloud data is in progress, in a visibility determination process that prioritizes reducing the processing load. Then, in addition to terminating the process, the station location and area design support device 1 displays a warning (alert) to prompt the user to target other candidate base station installation locations for the visibility determination process based on point cloud data.

A warning display (alert) is a display that informs the user of, for example, "At this proposed location for base station installation, there will be many areas with no line of sight to the base station, resulting in a narrower range for terminal stations. We recommend that you reevaluate other proposed locations for the base station."

Figure 34 is a diagram for explaining the termination conditions of the visibility assessment process based on point cloud data for a certain candidate installation location of a base station. The horizontal axis of the graph shown in Figure 34 represents the number Cp of representative points for which the visibility assessment process based on point cloud data has been performed for a certain candidate installation location of a base station. Meanwhile, the vertical axis of the graph shown in Figure 34 represents the number Co of representative points that have been determined to have visibility out of the number Cp of representative points for which the visibility assessment process based on point cloud data has been performed.

Furthermore, when performing station placement and area design to maximize area and when performing visibility assessment with priority given to reducing processing load, if the number of representative points to be subject to visibility assessment is Ca, then Cp (the number of visibility assessments performed), which is the horizontal axis of the graph shown in Figure 34, will be Cp < Ca at a point midway through the visibility assessment process, and Cp = Ca at the completion of the visibility assessment process.

Furthermore, of the number Cp of representative points for which visibility determination processing based on point cloud data has been performed, the number Cn of representative points for which visibility has been determined to be non-existent is taken as the number. When performing visibility determination prioritizing reduction in processing load, the number of representative points determined to have visibility is Co, so the number Ca of points for which visibility determination processing has been performed at the time the visibility determination processing is completed can be expressed as Ca = Co + Cn.

When performing visibility assessment with priority on accuracy, Ca is expressed as Ca < Co + Cn. This is because when performing visibility assessment with priority on accuracy, visibility assessment may be performed between the same representative point and multiple base station installation candidate locations. In this embodiment, as an example, we will explain the case where visibility assessment with priority on reducing processing load is performed, that is, we will explain the case where the relationship Ca = Co + Cn holds.

Below, we consider how much of the visibility assessment process based on point cloud data has been completed at a midpoint in the visibility assessment process. As mentioned above, the total number of visibility assessment processes based on point cloud data is Ca. Note that, when performing station placement and area design to maximize area and when performing visibility assessment that prioritizes reducing processing load, this Ca corresponds to the total number of representative points that have been determined to have visibility by the visibility assessment based on map information. Also, as mentioned above, the number of visibility assessment processes based on point cloud data that have been performed is Cp.

As a result, if the percentage of visibility assessment processing based on point cloud data that was performed (hereinafter also referred to as the "achievement rate") is Rp/a, it can be expressed as Rp/a = Cp ÷ Ca. Then, at the point where the visibility assessment processing based on point cloud data is completed, Rp/a = 100 [%]. Based on this achievement rate Rp/a, Cp on the horizontal axis of the graph shown in Figure 34 can also be expressed as Cp = Rp/a x Ca.

Generally, the result of the visibility judgment based on the point cloud data can be predicted with a certain degree of certainty at the midpoint of the visibility judgment process, before the completion of the visibility judgment process based on the point cloud data, i.e., before Rp/a = 100 [%]. Therefore, let Th0 be the threshold value that represents the percentage of likely judgment results obtained in the visibility judgment based on the point cloud data. In the graph shown in Figure 34, this threshold Th0 exists somewhere between the value of Cp on the horizontal axis, which is between 0 and Ca.

When the rate (achievement rate) Rp/a of visibility assessment processing based on point cloud data is equal to or greater than Th0, it is possible to predict the number of representative points that are determined to have visibility at the time when all visibility assessment processing is completed. In the graph shown in Figure 34, the shaded area represents the time when the achievement rate is equal to or greater than Th0.

In addition, the threshold value representing the acceptable ratio of representative points determined to have visibility during the visibility determination process based on the point cloud data is Th1. In addition, the ratio of representative points determined to have visibility during the visibility determination process based on the point cloud data is Ro/a.

Here, if Ro/a<Th1 (i.e., if it is within the range shaded darkly in the graph shown in Figure 34), then the number of representative points determined to have no visibility is too large, and so it is predicted that the communication area will not be widened at the candidate base station installation location being evaluated. Therefore, the station placement and area design support device 1 gives up on and ends the evaluation of the visibility judgment based on the point cloud data for the candidate base station installation location even if the evaluation is in progress, and moves on to the visibility judgment process for other candidate base station installation locations.

In the visibility assessment process that prioritizes reducing the processing load in the first embodiment described above, the map visibility assessment unit 41 was configured to terminate the visibility assessment process based on the point cloud data when the proportion of representative points that were determined to have visibility by the visibility assessment based on map information and for which a visibility assessment based on point cloud data was also performed is equal to or greater than a predetermined threshold. This threshold is hereinafter referred to as Th3.

Furthermore, Th2 is a threshold value representing an acceptable proportion of the proportion of representative points that are determined to have visibility at the achievement rate Rp/a = Th3 (i.e., the end point of the visibility determination process based on the point cloud data).

When Ro/a<Th2, as in the case of Ro/a<Th1 above, there are too many representative points that are determined to have no visibility, and therefore it is understood that the communication area will not be widened at the candidate base station installation location being evaluated. Therefore, the station placement and area design support device 1 gives up on and ends the evaluation of the visibility judgment based on the point cloud data for the candidate base station installation location even if the evaluation is in progress, and moves on to the visibility judgment process for other candidate base station installation locations.

Here, the magnitude relationship between thresholds Th1 and Th2 is Th1 < Th2. The reason for this is that the value of the proportion Ro/p of representative points determined to have visibility at an intermediate point in the visibility determination process based on the point cloud data may become larger through subsequent visibility determination processing, whereas the value of the proportion Ro/a of representative points determined to have visibility at the completion of the visibility determination process based on the point cloud data is a fixed value. Therefore, threshold value Th1 at an intermediate point in the visibility determination process is set smaller than threshold value Th2 at the completion of the visibility determination process.

The flow of visibility determination processing with priority given to reducing the processing load is described below. Figure 35 is a flowchart showing the operation of station placement and area design support device 1 in a visibility determination with priority given to reducing the processing load in the third embodiment of the present invention. The operation of station placement and area design support device 1 shown in the flowchart of Figure 35 is basically a detailed version of the operation of step S16 shown in Figure 2 in the first embodiment described above.

The processing of steps S361 to S365 in the flowchart shown in FIG. 35 is similar to the processing of steps S161 to S165 in the flowchart shown in FIG. 20 described above, and therefore will not be described.

In step S365, the three-dimensional visibility assessment unit 42 updates the assessment feasibility list 304, deletes the combination of the base station installation candidate location and representative point for which the assessment result of the visibility assessment based on the point cloud data is recorded from the list of combinations that are determined to have visibility by the visibility assessment based on the map information, and then calculates the achievement rate Rp/a (step S366).

If the achievement rate Rp/a does not meet the threshold value Th0 (step S366, NO), the process returns to the loop of step S363 or step S361, and the 3D visibility assessment unit 42 further performs visibility assessment based on the point cloud data for other base station installation candidate locations and other representative points.

On the other hand, if the achievement rate Rp/a is greater than or equal to the threshold value Th0 (step S366, YES), the 3D visibility assessment unit 42 checks whether the proportion of representative points that are determined to have no visibility based on the point cloud data is high (step S367).

Specifically, the 3D visibility assessment unit 42 checks whether the value of Ro/p, which is the proportion of representative points determined to have no visibility by a visibility assessment based on point cloud data, is Ro/p < Th1 (i.e., the proportion of representative points determined to have no visibility is high) or Ro/p ≥ Th1 (i.e., the proportion of representative points determined to have no visibility is low).

If the proportion of representative points that are determined to have no visibility based on the point cloud data is high (step S367: YES, i.e., Ro/p<Th1), the visibility assessment process for the base station installation candidate location currently being evaluated is terminated. Then, the output unit 50 displays a warning (alert) to prompt the user to perform visibility assessment process based on the point cloud data with other base station installation candidate locations as evaluation targets (step S370). This concludes the operation of the station placement and area design support device 1 shown in the flowchart of Figure 35.

On the other hand, if the proportion of representative points that are determined to have no visibility by the visibility judgment based on the point cloud data is small (step S367: NO, i.e., if Ro/p≧Th1), the map visibility judgment unit 41 judges whether the proportion of representative points that are determined to have visibility by the visibility judgment based on the map information and for which a visibility judgment based on the point cloud data has been further performed is equal to or greater than a predetermined threshold value Th3 (step S368).

If the proportion of representative points for which a visibility determination based on map information has been performed and for which a visibility determination based on point cloud data has also been performed is less than a predetermined threshold value Th3 (step S368, NO), the process returns to step S363 or step S361, and the 3D visibility determination unit 42 further performs visibility determination based on point cloud data for other candidate base station installation locations and other representative points.

On the other hand, if the proportion of representative points for which a visibility determination based on map information has been performed and for which a visibility determination based on point cloud data has also been performed is equal to or greater than a predetermined threshold value Th3 (step S368, YES), the 3D visibility determination unit 42 checks whether the proportion of representative points for which visibility has been determined to be poor by the visibility determination based on point cloud data is high (step S369).

Specifically, the 3D visibility assessment unit 42 checks whether the value of Ro/p, which is the proportion of representative points determined to have no visibility by a visibility assessment based on point cloud data, is Ro/p < Th2 (i.e., the proportion of representative points determined to have no visibility is high) or Ro/p ≥ Th2 (i.e., the proportion of representative points determined to have no visibility is low).

If the proportion of representative points that are determined to have no visibility based on the point cloud data is high (step S369: YES, i.e., Ro/p<Th2), the visibility assessment process for the base station installation candidate location currently being evaluated is terminated. Then, the output unit 50 displays a warning (alert) to prompt the user to perform visibility assessment process based on the point cloud data with other base station installation candidate locations as evaluation targets (step S370). This concludes the operation of the station placement and area design support device 1 shown in the flowchart of Figure 35.

On the other hand, if the proportion of representative points that are determined to have no visibility based on the point cloud data is small (step S369, NO; i.e., Ro/p≧Th2), the map visibility determination unit 41 terminates the visibility determination process that prioritizes reducing the processing load. This completes the operation of the station placement and area design support device 1 shown in the flowchart of Figure 35.

By being provided with the above-described configuration, the station location and area design support device 1 in this embodiment can stop the visibility assessment process based on point cloud data for a base station installation candidate location that is unlikely to be able to secure a wide communication area midway through the process, without needlessly running the process to the end. This allows the station location and area design support device 1 to more quickly start the visibility assessment process based on point cloud data for other base station installation candidate locations that are likely to be able to secure a wide communication area.

In particular, the above-described configuration of the station placement and area design support device 1 in this embodiment is considered to be a configuration suitable for performing station placement and area design to maximize area. As explained in the first embodiment with reference to FIG. 8, etc., when performing station placement and area design to maximize area, a representative point that has only one candidate installation location for a base station that has been determined to have line of sight based on map information is given priority, and line of sight determination is performed before other representative points.

If the representative point for which only one base station candidate installation location has been determined to have line of sight is determined to have no line of sight through a line of sight determination based on point cloud data, it will not be determined to have line of sight to other base station candidate installation locations. Therefore, it is wise to terminate the line of sight determination based on point cloud data for the base station candidate installation location as soon as possible and redo the line of sight determination based on point cloud data for the other base station candidate installation locations.

Therefore, the above-mentioned configuration of the station location/area design support device 1 can quickly abandon visibility assessment processing based on point cloud data for candidate base station installation locations that are unlikely to secure a wide communication area, and is therefore considered to be suitable for station location/area design that aims to maximize area, as mentioned above.

Fourth Embodiment
The station location and area design support device 1 in the fourth embodiment described below, in contrast to the configuration of the station location and area design support device 1 in the third embodiment described above, identifies base station node candidate positions that are likely to ensure a wide communication area (i.e., have line of sight to many representative points) at a midpoint of visibility determination processing that prioritizes reduction in processing load.The station location and area design support device 1 can then switch to accuracy-priority processing earlier for the identified base station node candidate positions and start visibility determination processing based on point cloud data.

The flow of visibility determination processing with priority given to reducing the processing load is described below. Figure 36 is a flowchart showing the operation of station placement and area design support device 1 in a visibility determination with priority given to reducing the processing load in the fourth embodiment of the present invention. The operation of station placement and area design support device 1 shown in the flowchart of Figure 36 is basically a detailed version of the operation of step S16 shown in Figure 2 in the first embodiment described above.

The processing of steps S461 to S465 in the flowchart shown in FIG. 36 is similar to the processing of steps S161 to S165 in the flowchart shown in FIG. 20 described above, and therefore will not be described.

In step S465, the three-dimensional visibility assessment unit 42 updates the assessment feasibility list 304, deletes the combination of the base station installation candidate location and representative point for which the assessment result of the visibility assessment based on the point cloud data is recorded from the list of combinations that are determined to have visibility by the visibility assessment based on the map information, and then calculates the achievement rate Rp/a (step S466).

If the achievement rate Rp/a does not meet the threshold value Th0 (step S466: NO), the process returns to step S463 or step S461, and the 3D visibility assessment unit 42 further performs visibility assessment based on the point cloud data for other base station installation candidate locations and other representative points.

On the other hand, if the achievement rate Rp/a is greater than or equal to the threshold value Th0 (step S466, YES), the 3D visibility assessment unit 42 checks whether the proportion of representative points that are determined to have no visibility based on the point cloud data is high (step S467).

Specifically, the 3D visibility assessment unit 42 checks whether the value of Ro/p, which is the proportion of representative points determined to have visibility by a visibility assessment based on point cloud data, is Ro/p < Th1' (i.e., the proportion of representative points determined to have visibility is small) or Ro/p ≥ Th1' (i.e., the proportion of representative points determined to have visibility is large).

If the proportion of representative points that are determined to have visibility based on the point cloud data is high (step S467: YES, i.e., Ro/p≧Th1'), the system switches to a visibility determination process that prioritizes accuracy. This completes the operation of the station placement and area design support device 1 shown in the flowchart of Figure 36.

On the other hand, if the proportion of representative points determined to have visibility by the visibility judgment based on the point cloud data is small (step S467, NO; i.e., if Ro/p<Th1'), the map visibility judgment unit 41 judges whether the proportion of representative points that have been further subjected to visibility judgment based on point cloud data, among the representative points determined to have visibility by the visibility judgment based on the map information, is equal to or greater than a predetermined threshold value Th3 (step S468).

If the proportion of representative points for which a visibility determination based on map information has been performed and for which a visibility determination based on point cloud data has also been performed is less than a predetermined threshold Th3 (step S468, NO), the process returns to step S463 or step S461, and the 3D visibility determination unit 42 further performs visibility determination based on point cloud data for other candidate base station installation locations and other representative points.

On the other hand, if the proportion of representative points for which a visibility determination based on map information has been performed and for which a visibility determination based on point cloud data has also been performed is equal to or greater than a predetermined threshold value Th3 (step S468, YES), the 3D visibility determination unit 42 checks whether the proportion of representative points that have been determined to have visibility by the visibility determination based on point cloud data is high (step S469).

Specifically, the 3D visibility assessment unit 42 checks whether the value of Ro/p, which is the proportion of representative points determined to have visibility by a visibility assessment based on point cloud data, is Ro/p≧Th2' (i.e., the proportion of representative points determined to have visibility is high) or Ro/p<Th2' (i.e., the proportion of representative points determined to have visibility is low).

If the proportion of representative points that are determined to have visibility based on the point cloud data is high (step S469: YES, i.e., Ro/p<Th2'), the system switches to a visibility determination process that prioritizes accuracy. This completes the operation of the station placement and area design support device 1 shown in the flowchart of Figure 36.

On the other hand, if the ratio of representative points determined to have no visibility based on the point cloud data is small (step S469 : NO, i.e., Ro/p≧Th2′), the map visibility determination unit 41 ends the visibility determination process that prioritizes reduction in processing load. This ends the operation of the station location and area design support device 1 shown in the flowchart of FIG.

In the flowchart shown in FIG. 36, four thresholds, Th0, Th1', Th2', and Th3, are used. Here, for Th0 and Th3, which are thresholds related to whether or not visibility determination processing has been performed, the same thresholds as those in the flowchart shown in FIG. 35 of the third embodiment described above are used. On the other hand, for Th1' and Th2', which are thresholds related to the results of visibility determination processing for each representative point, thresholds different from those in the flowchart shown in FIG. 35 of the third embodiment described above are used. However, depending on the situation in which the station placement/area design support device 1 in this embodiment is used, thresholds different from those in the flowchart shown in FIG. 35 of the third embodiment described above may be used.

With the above-described configuration, the station location and area design support device 1 in this embodiment determines whether or not a base station installation candidate location is likely to be able to secure a wide communication area at a midpoint in the visibility determination process based on the point cloud data. The station location and area design support device 1 can then switch the visibility determination process based on the point cloud data for a base station installation candidate location that is likely to be able to secure a wide communication area from a processing burden reduction priority mode to an accuracy priority mode at an earlier stage.

Fifth embodiment
In the evaluation area shown in Fig. 3, for example, when viewed from the base station installation candidate location A, the representative points marked with the symbols (5), (8), (9), and (13) are located in approximately the same direction. Therefore, if the result of the line of sight determination based on the point cloud data between the representative point marked with the symbol (13) that is the furthest from the base station installation candidate location A and the base station installation candidate location A is "line of sight", it is estimated that the result of the line of sight determination based on the point cloud data between the representative points marked with the symbols (5), (8), and (9) and the base station installation candidate location A is also "line of sight". This is because the representative points marked with the symbols (5), (8), and (9) are located between the base station installation candidate location A and the representative point marked with the symbol (13).

The station location/area design support device 1 in this embodiment can perform station location/area design that further reduces the processing burden by omitting some of the visibility assessment processing based on point cloud data for multiple representative points that exist in the same direction from the candidate base station installation location.

Figures 37 and 38 are diagrams for explaining station placement and area design in the fifth embodiment of the present invention. Figure 37 shows how the evaluation area shown in Figure 3 is divided even finer (into meshes of half the length both vertically and horizontally) on a two-dimensional plane. For example, the mesh having a representative point marked (1) is divided into four meshes having representative points marked (1)-1, (1)-2, (1)-3, and (1)-4, respectively.

As in the second embodiment described above, in this embodiment too the shape of the Fresnel zone of the ellipsoid is considered to be cylindrical.

Figure 38 also shows the area determined to have visibility from base station installation candidate location A in Figure 37 (based on a visibility determination based on map information), as viewed from an oblique angle.

Figure 38 shows base station A installed at candidate installation location A, which is located within a mesh having a representative point marked (5)-1. For example, when viewed from base station A, the meshes having representative points marked (1)-4, (1)-3, (2)-4, (4)-1, and (4)-2 are located in approximately the same direction.

In this embodiment, when multiple representative points exist in the same direction as seen from a candidate base station installation location, the station location and area design support device 1 first performs visibility assessment processing based on point cloud data between the farthest representative point and the candidate base station installation location. In the evaluation area illustrated in Figure 38, the station location and area design support device 1 first performs visibility assessment processing based on point cloud data between candidate base station installation location A and the representative point marked (1)-4.

If the result of the line of sight determination process based on the point cloud data between the base station installation candidate location A and the representative point marked with (1)-4 is "line of sight," the station placement and area design support device 1 determines that there is "line of sight" between the representative points marked with (1)-3, (2)-4, (4)-1, and (4)-2 and the base station installation candidate location A without performing line of sight determination process based on the point cloud data. This is because the representative points marked with (1)-3, (2)-4, (4)-1, and (4)-2 are representative points that exist in the same direction as the representative point marked with (1)-4 when viewed from the base station installation candidate location A, and are representative points that exist in front of the representative point marked with (1)-4.

On the other hand, if the result of the visibility assessment process based on the point cloud data between the base station installation candidate location A and the farthest representative point (i.e., the representative point marked with (1)-4) is "no visibility," the station placement and area design support device 1 then performs visibility assessment process based on the point cloud data between the closest representative point and the base station installation candidate location. In the evaluation area illustrated in Figure 38, the station placement and area design support device 1 then performs visibility assessment process based on the point cloud data between the representative point marked with (4)-2 and the base station installation candidate location.

If the result of the line of sight assessment process based on the point cloud data between the base station installation candidate location A and the representative point marked (4)-2 is "no line of sight," the station placement/area design support device 1 determines that there is "no line of sight" between the representative points marked (1)-3, (2)-4, and (4)-1, respectively, and the base station installation candidate location A without performing line of sight assessment process based on the point cloud data.

On the other hand, if the result of the visibility assessment process based on the point cloud data between the base station installation candidate location A and the representative point marked (4)-2 is "visibility available," the station placement and area design support device 1 then performs visibility assessment process based on the point cloud data between the midpoint representative point and the base station installation candidate location. In the evaluation area illustrated in Figure 38, the station placement and area design support device 1 then performs visibility assessment process based on the point cloud data between the representative point marked (2)-4 and the base station installation candidate location.

If the result of the line of sight determination process based on the point cloud data between the base station installation candidate location A and the representative point marked with (2)-4 is "line of sight," the station placement/area design support device 1 determines that there is "line of sight" between the representative point marked with (4)-1 and the base station installation candidate location A without performing line of sight determination process based on the point cloud data. In addition, the station placement/area design support device 1 performs line of sight determination process based on the point cloud data between the representative point marked with (1)-3 and the base station installation candidate location A.

On the other hand, if the result of the line of sight determination process based on the point cloud data between the base station installation candidate location A and the representative point marked (2)-4 is "no line of sight," the station placement/area design support device 1 determines that there is "no line of sight" between the representative point marked (1)-3 and the base station installation candidate location A without performing line of sight determination process based on the point cloud data. In addition, the station placement/area design support device 1 performs line of sight determination process based on the point cloud data between the representative point marked (4)-1 and the base station installation candidate location A.

In this way, the station location and area design support device 1 in this embodiment performs a binary search for multiple representative points that exist in the same direction as seen from a candidate base station installation location, and identifies the position that is the boundary between representative points that have line of sight to the candidate base station installation location and representative points that do not have line of sight to the candidate base station installation location. Then, for representative points for which a line of sight determination based on point cloud data was not performed in the above search, the station location and area design support device 1 in this embodiment determines whether "line of sight" or "no line of sight" is present, based on the determination results for the other representative points.

In this embodiment, when there are multiple representative points in the same direction as seen from a certain base station installation candidate location, the station placement/area design support device 1 is configured to first start a binary search by performing visibility determination processing based on point cloud data between the farthest representative point and the base station installation candidate location, and identify the position that is the boundary between a representative point that has visibility to the base station installation candidate location and a representative point that does not have visibility to the base station installation candidate location. However, this configuration is not limited, and for example, the station placement/area design support device 1 may be configured to first start a binary search by performing visibility determination processing based on point cloud data between the nearest representative point and the base station installation candidate location.

That is, for example, in the evaluation area shown in FIG. 38, the station location and area design support device 1 first performs a visibility assessment process based on the point cloud data between the base station installation candidate location A and the representative point marked with (4)-2. Then, if the result of the visibility assessment is "no visibility", the station location and area design support device 1 determines that there is "no visibility" between the representative points marked with (1)-4, (1)-3, (2)-4, and (4)-1 and the base station installation candidate location A without performing visibility assessment process based on the point cloud data. This is because if there is no visibility to the closest representative point among multiple representative points existing in the same direction, it is predicted that there is a high possibility that there is also no visibility to each representative point existing on an extension beyond this closest representative point.

By having such a configuration, the station location/area design support device 1 in this embodiment can further reduce the processing burden by omitting some of the visibility determination processing based on point cloud data.

In each of the above embodiments, millimeter wave radio has been shown as an example of wireless communication between the base station and the terminal station, but other types of communication may also be used, such as terrestrial digital communication, communication using satellite radio waves, or communication using UHF (Ultra High Frequency).

According to the above-described embodiment, the station placement design support device includes an acquisition unit, a first estimation unit, a determination unit, a second estimation unit, and a termination control unit. For example, the station placement design support device is the station placement/area design support device 1 in the embodiment, the acquisition unit is the base station candidate position selection unit 202 and the area division unit 14 in the embodiment, the first estimation unit and the determination unit are the map visibility determination unit 41 in the embodiment, and the second estimation unit and the termination control unit are the 3D visibility determination unit 42 in the embodiment.

The acquisition unit acquires candidate positions of wireless base stations in a target area and representative points representing positions where mobile stations may be located in each mesh of the target area divided into mesh shapes. For example, the target area is an evaluation target area in the embodiment, the wireless base station is a base station in the embodiment, and the mobile station is a terminal station in the embodiment.

The first estimation unit estimates whether communication is possible between each of the candidate positions of the wireless base station and the representative point based on first information indicating the position of an object present in the target area. For example, the candidate positions are candidate positions for installing the base station in the embodiment, the position of the object is an obstruction such as a building in the map in the embodiment (e.g., the outer periphery of the obstruction), and the first information is map/area information 302 in the embodiment.

The determination unit determines a combination of the candidate positions of the wireless base stations and the representative points estimated by the first estimation unit as being capable of communication, for which a process of estimating whether or not communication is possible is further performed based on second information having a larger amount of information than the first information. For example, the second amount of information is point cloud data in the embodiment, and the process of estimating whether or not communication is possible is a process of determining visibility based on the point cloud data in the embodiment.

The second estimation unit estimates whether communication is possible between each of the candidate positions of the wireless base station and the representative point, which is the combination determined by the determination unit, based on the second information.

The end control unit ends the estimation process by the second estimation unit according to a rule defined for each of the designated station placement design methods. For example, the station placement design methods are processing modes such as a processing load reduction mode and an accuracy priority mode in the embodiment, and the rule defined for each station placement design method is a rule in the embodiment that the map visibility determination unit 41 ends the visibility determination process with priority to processing load reduction when the ratio of representative points determined to have visibility by the visibility determination based on map information and for which visibility determination based on point cloud data is further performed is equal to or greater than a predetermined threshold, and a rule that the map visibility determination unit 41 ends the visibility determination process with priority to accuracy when the ratio of representative points determined to have visibility by the visibility determination based on map information and for which visibility determination based on point cloud data is also determined to have visibility is equal to or greater than a predetermined threshold (for example, the determination rule in step S177 in the flowchart shown in FIG. 21).

The termination control unit may terminate the estimation process when the ratio of combinations for which the communication possibility is estimated by the second estimation step among the combinations determined by the determination unit reaches a predetermined ratio. For example, the predetermined ratio is a ratio corresponding to the threshold value Th3 in the embodiment.

In addition, the termination control unit may terminate the estimation process when the proportion of combinations determined by the determination unit that are estimated to be capable of communication by the second estimation step reaches a predetermined proportion.

The second estimation unit may estimate whether communication is possible based on the amount of second information contained in a cylindrical space that approximates a Fresnel zone formed between each of the candidate positions of the wireless base station and the representative point. For example, the Fresnel zone is Fresnel zone fz in the embodiment, and the cylindrical space is cylindrical Fresnel zone Cz in the embodiment.

In addition, when the ratio of combinations estimated by the second estimation unit as being unable to communicate among the combinations estimated by the second estimation unit as being capable of communication reaches a predetermined ratio while the estimation process is being performed by the second estimation unit, information indicating a warning may be output. For example, the predetermined ratio is a ratio corresponding to threshold value Th1 and a ratio corresponding to threshold value Th2 in the embodiment, and the information indicating a warning is a warning display (alert) in the embodiment.

In addition, when the ratio of combinations estimated to be communicable among the combinations estimated to be communicable reaches a predetermined ratio during the estimation process, the second estimation unit may switch to an estimation method with higher estimation accuracy and perform the subsequent estimation process. For example, the predetermined ratio is a ratio corresponding to threshold value Th1' and a ratio corresponding to threshold value Th2' in the embodiment, and the estimation method with higher estimation accuracy is visibility judgment in the accuracy priority mode in the embodiment.

In addition, when multiple representative points exist in the same direction from the candidate position of the radio base station and it is estimated that communication is possible between the candidate position of the radio base station and the representative point among the representative points that is located at a position farthest from the candidate position of the radio base station, the second estimation unit may be configured to estimate that communication is also possible between other representative points existing in the same direction and the candidate position of the radio base station.

The first information may be map information indicating a two-dimensional map, and the second information may be three-dimensional point cloud data indicating the surface positions of objects present within the map.

The station placement and area design support device 1 in each of the above-mentioned embodiments may be realized 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 the recording medium may be read into a computer system and executed to realize the function. The term "computer system" as used herein includes hardware such as an OS and peripheral devices. The term "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, and storage devices such as hard disks built into a computer system. The term "computer-readable recording medium" may also include a medium that dynamically holds a program for a short period of time, such as a communication line when a program is transmitted via a network such as the Internet or a communication line such as a telephone line, and a medium that holds a program for a certain period of time, such as a volatile memory inside a computer system that is a server or client in that case. The above-mentioned program may be a program for realizing part of the above-mentioned functions, or may be a program that can realize the above-mentioned functions in combination with a program already recorded in the computer system, or may be a program that is realized using a programmable logic device such as an FPGA (Field Programmable Gate Array).

The above describes in detail an embodiment of the present invention with reference to the drawings, but the specific configuration is not limited to this embodiment and also includes designs that do not deviate from the gist of the present invention.

Reference Signs List 1... Station location/area design support device, 11... Equipment information acquisition unit, 12... Base station installation candidate position extraction unit, 13... Map information acquisition unit, 14... Area division unit, 15... Point cloud data acquisition unit, 16... Data matching unit, 20... Operation input unit , 30 ... Memory unit, 41... Map visibility determination unit, 42... 3D visibility determination unit, 43... 3D determination feasibility evaluation unit, 50... Output unit, 201... Evaluation area selection unit, 202... Base station candidate position selection unit, 203... Design method designation unit, 204... Processing mode designation unit, 301... Base station installation candidate position information, 302... Map/area information, 303... Point cloud data, 304... Determination feasibility list, 305... Station location/area design result information

Claims (8)

an acquisition step of acquiring candidate positions of wireless base stations in a target area and representative points representing positions where mobile stations may exist in each mesh of the target area divided into mesh shapes;
a first estimation step of estimating whether communication is possible between the candidate positions of the wireless base station and each of the representative points based on first information indicating a position of an object present in the target area;
a determination step of determining a combination of the candidate positions of the wireless base stations estimated to be communicable by the first estimation step and the representative point, the combination being further subjected to an estimation process of whether or not communication is possible based on second information having a larger amount of information than the first information, the second information being data indicating a position of an obstruction ;
a second estimation step of estimating, based on the second information, whether communication is possible between the candidate positions of the wireless base station, which are the combinations determined in the determination step, and each of the representative points;
a termination step of terminating the estimation process by the second estimation step according to a rule defined for each designated station placement design method;
The present invention relates to a station placement design support method. 2. The station placement design support method according to claim 1, wherein the termination step terminates the estimation process when a ratio of combinations for which the communication possibility is estimated by the second estimation step among the combinations determined by the determination step reaches a predetermined ratio. 2. The station placement design support method according to claim 1, wherein the termination step terminates the estimation process when a ratio of combinations estimated to be communicable in the second estimation step among the combinations determined in the determination step reaches a predetermined ratio. 4. The station location design support method according to claim 1 , wherein the second estimation step estimates the possibility of communication based on an amount of the second information included in a cylindrical space approximating a Fresnel zone formed between the candidate positions of the radio base station and each of the representative points. 5. The station placement design support method according to claim 1, further comprising: outputting information indicating a warning when a ratio of combinations estimated as being unable to communicate by the second estimation step among combinations estimated as being unable to communicate by the second estimation step reaches a predetermined ratio during the estimation process by the second estimation step. 6. The station placement design support method according to claim 1, wherein the second estimation step switches to an estimation method with higher estimation accuracy when a ratio of combinations estimated to be communicable among combinations for which the communication possibility has been estimated reaches a predetermined ratio during the estimation process, and performs the subsequent estimation process. 7. The station location design support method according to claim 1 , wherein, when a plurality of representative points exist in the same direction from the candidate position of the radio base station, and it is estimated that communication is possible between the candidate position of the radio base station and the representative point that is farthest from the candidate position of the radio base station among the representative points, it is estimated that communication is also possible between the other representative points that exist in the same direction and the candidate position of the radio base station. an acquisition unit that acquires candidate positions of wireless base stations in a target area and representative points that represent positions where mobile stations may exist in each mesh of the target area that is divided into a mesh shape;
a first estimation unit that estimates whether communication is possible between the candidate positions of the wireless base station and each of the representative points based on first information indicating a position of an object present in the target area;
a determination unit that determines a combination of the candidate positions of the wireless base stations estimated by the first estimation unit to be communicable with the representative point, the combination being second information having an amount of information larger than that of the first information, the second information being data indicating a position of an obstruction, and further performs an estimation process of whether communication is possible or not based on the second information ;
a second estimation unit that estimates whether communication is possible between the candidate positions of the wireless base station, which is the combination determined by the determination unit, and each of the representative points, based on the second information;
a termination control unit that terminates the estimation process by the second estimation unit according to a rule defined for each designated station placement design method;
A station placement design support device comprising:

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