Station placement design device, station placement design method, station placement design program, and recording medium

Abstract

The station location design device includes: a propagation loss calculation unit (7) that sequentially performs radio wave propagation analysis between a radio wave arrival area calculation point that is stored in a radio wave arrival area calculation point storage unit (5) and has the shortest straight-line distance from a reference point of a base station candidate area (30) and each of a plurality of base station candidate points stored in a base station candidate point storage unit (4), and sequentially performs radio wave propagation analysis between each of the remaining radio wave arrival area calculation points stored in the radio wave arrival area calculation point storage unit (5) and each of the remaining base station candidate points stored in the base station candidate point storage unit (4); and a base station selection unit (8) that sequentially compares the propagation losses that are analyzed by the propagation loss calculation unit (7) and received sequentially with a threshold, deletes base station candidate points whose propagation loss is equal to or greater than the threshold from the base station candidate point storage unit (4), and sets the base station candidate point that is immediately before all the base station candidate points stored in the base station candidate point storage unit (4) are deleted as the selection result.

Description

[Technical Field]

[0001] The present disclosure relates to a station placement design device, a station placement design method, a station placement design program, and a recording medium that select the placement of base stations in a mobile communication system. [Background technology]

[0002] In the field of station location design, which determines the location of a base station, Patent Document 1 discloses a station location design device that can calculate the location where propagation loss is minimized without increasing the amount of calculation. The station location design device shown in Patent Document 1 includes a candidate setting unit that determines candidate locations for placing base stations in an area that indicates the location of buildings; an area dividing unit that divides the area into multiple meshes; an area calculation unit that calculates the integrated value (line-of-sight area) of the mesh area determined based on the positional relationship between the candidate, the building, and each center of the mesh; a candidate extraction unit that extracts top candidates according to the integrated value; a propagation loss calculation unit that calculates the propagation loss of radio waves for each of the top candidates; a propagation loss determination unit that determines whether the propagation loss is less than a threshold value; and a location selection unit 170 that selects the candidate with the largest integrated value of the mesh area that indicates a propagation loss that is less than the threshold value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-234091 Summary of the Invention [Problem to be solved by the invention]

[0004] The station location design device disclosed in Patent Document 1 extracts top station location candidates according to the line-of-sight area, so there is a risk that the optimal station location candidate may be eliminated before the propagation loss is calculated.

[0005] The present disclosure has been made in consideration of the above points, and aims to provide a base station placement design device that can select a base station from an evaluation based on propagation loss for all base station candidate points that can be placed within a base station candidate area, without increasing the amount of calculations. [Means for solving the problem]

[0006] a propagation loss calculation unit that sequentially performs radio wave propagation analysis between the radio wave arrival area calculation point stored in the radio wave arrival area calculation point storage unit and each of the plurality of base station candidate points stored in the base station candidate point storage unit, the radio wave arrival area calculation point being closest in straight-line distance from a reference point of the base station candidate area, and the plurality of base station candidate points stored in the base station candidate point storage unit, and sequentially performs radio wave propagation analysis between each of the remaining radio wave arrival area calculation points stored in the radio wave arrival area calculation point storage unit and each of the remaining base station candidate points stored in the base station candidate point storage unit; and a base station selection unit that sequentially compares the propagation losses that have been analyzed by the propagation loss calculation unit and received sequentially with a threshold, deletes base station candidate points whose propagation loss is equal to or greater than the threshold from the base station candidate point storage unit, and sets the base station candidate point that was stored in the base station candidate point storage unit immediately before all of the base station candidate points were deleted as the selection result. [Effects of the Invention]

[0007] According to the present disclosure, a base station can be selected from all base station candidate points that can be placed within a base station candidate area through evaluation based on propagation loss, without increasing the amount of calculation. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a block diagram showing a station placement design apparatus according to a first embodiment. [Figure 2] 10A and 10B are diagrams illustrating an example of an area acquired from map information, and base station candidate areas and coverage areas within the area. [Figure 3]FIG. 3 is a diagram showing an example of base station candidate points and radio wave coverage area calculation points set in FIG. 2. [Figure 4] 5 is a flowchart showing an outline of a processing procedure for station placement design performed by the station placement design device according to the first embodiment. [Figure 5] 1 is a configuration diagram showing a hardware configuration of a station placement design apparatus according to a first embodiment. [Figure 6] FIG. 10 is a block diagram showing a station placement design apparatus according to a second embodiment. [Figure 7] FIG. 11 is a block diagram showing a station placement design apparatus according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Embodiment 1 The station placement design device according to the first embodiment will be described with reference to FIGS. As shown in FIG. 1 , the station location design device according to the first embodiment includes a map information storage unit 1, an area setting unit 2, a station location candidate point setting unit 3, a base station candidate point storage unit 4, a radio wave coverage area calculation point setting unit 5, a radio wave coverage area calculation point storage unit 6, a propagation loss calculation unit 7, a base station selection unit 8, and a station location determination unit 9.

[0010] The map information storage unit 1 stores map information input from an input unit (not shown). The map information includes, for example, information indicating the positions (locations) of buildings, the heights of buildings, the widths of roads, and the positions of vacant lots. The map information is information for representing a two-dimensional planar map of an urban area, which is an example of an outdoor environment to be analyzed for radio wave propagation, viewed from above. In other words, the map information is two-dimensional map data representing a two-dimensional map. However, the map information may also be three-dimensional map data representing a three-dimensional map.

[0011] The area setting unit 2 sets an area in which services are provided by radio waves transmitted by a base station based on the map information stored in the map information storage unit 1, and acquires area data for the set area (hereinafter referred to as the set area) 100. The area data includes, for example, information indicating the topography, buildings 11 to 14 and other structures 15, and roads 20, as shown in FIG. The area data is based on the base station candidate points A1 to A M The information includes information indicating a base station candidate area 30 in which the base station can be placed, and an area 40 in which a cover area is desired to be established in which communication between the base station and the mobile station is established.

[0012] That is, the area setting unit 2 sets base station candidate points A1 to A2, which are candidates for arranging base stations. M A base station candidate area 30 in which the base station can be placed and an area 40 in which a cover area in which communication between the base station and the mobile station is to be established are set in a setting area 100. The base station candidate area 30 is indicated by a dashed line in FIG.

[0013] Area 40 where we want to build a coverage area is shown by a dashed line in Figure 2, and is an area where we want to build a coverage area where the communication power between the base station and the mobile station exceeds the power required by the communication system and communication is possible. The area 40 where the coverage area is to be constructed is an area that is to be covered by the entire wireless system under consideration, and is composed of base station candidate points A1 to A2 that can be arranged in the base station candidate area 30. M This is not an area that the selected base station must necessarily cover. In the following description, the area 40 where a coverage area is to be established will be simply referred to as the coverage area 40 .

[0014] The station location candidate point setting unit 3 sets the base station candidate points A1 to A2, which are known in advance, in the base station candidate area 30 indicated by the area setting unit 2, as shown in FIG. M The base station candidate points A1 to A2 are arranged and set, and the position information indicating the arrangement position is linked to them. M The base station candidate point storage unit 4 stores information indicating the above. Base station candidate points A1~A M The arrangement of the base station candidate points A1 to A M There are no restrictions on spacing etc. Base station candidate points A1~AM The location information indicates, for example, the location of the antenna of the base station.

[0015] The radio wave coverage area calculation point setting unit 5 sets radio wave coverage area calculation points B1 to B2 within the cover area 40 defined by the area setting unit 2, as shown in FIG. N and calculate the radio wave coverage area by linking the location information to points B1 to B. N The information indicating this is stored in the radio wave coverage area calculation point storage unit 6. Radio wave coverage area calculation points B1~B N are assigned setting numbers in order of closest straight-line distance from the reference point of the base station candidate area 30.

[0016] That is, the radio wave coverage area calculation point B1 has the shortest straight-line distance from the reference point of the base station candidate area 30, and as the straight-line distance increases, so do B2, B3,...B. N are set in this order, and B N is set to the longest straight line distance from the reference point of the base station candidate area 30. The reference points of the base station candidate area 30 that serve as the standard for the straight-line distance are the base station candidate points A1 to A M or the base station candidate points A1 to A2 located at the farthest position from the edge of the coverage area 40. M This is the placement point. Radio wave coverage area calculation points B1~B N The location information indicates, for example, the location of the antenna of the mobile station.

[0017] The propagation loss calculation unit 7 calculates the radio wave arrival area calculation points B1 to B2 stored in the radio wave arrival area calculation point storage unit 6. N are read out in order of closest straight-line distance from the reference point of the base station candidate area 30, and the read out radio wave coverage area calculation points B1 to B N is used as a transmitting point, and the base station candidate points A1 to A2 stored in the base station candidate point storage unit 4 are M A radio wave propagation analysis was performed with the receiving point at n -A m ) is calculated.

[0018] The propagation loss calculation unit 7 calculates the propagation loss using commonly known ray tracing. Instead of ray tracing, a commonly known propagation loss estimation formula may be used, as long as it can analyze the radio wave propagation characteristics from the transmitting point to the receiving point and obtain the propagation loss.

[0019] The propagation loss calculation unit 7 first performs radio wave propagation analysis between the radio wave coverage area calculation point B1, which has the shortest straight-line distance from the reference point of the base station candidate area 30, and the base station candidate point A1, to find the propagation loss (B1-A1). The propagation loss (B1-A1) calculated by the propagation loss calculation unit 7 is received by the base station selection unit 8.

[0020] Next, the propagation loss calculation unit 7 performs a radio wave propagation analysis between the radio wave coverage area calculation point B1 and the base station candidate point A2, calculates the propagation loss (B1-A2), and sequentially transmits the radio wave coverage area calculation point B1. The radio wave propagation analysis is performed on the base station candidate points A1 to A2 stored in the base station candidate point storage unit 4. M The propagation loss (B1-A m ) is found. The propagation loss calculation unit 7 sequentially calculates the propagation loss (B1-A m ) are received by the base station selection unit 8 in sequence.

[0021] Thereafter, the propagation loss calculation unit 7 performs radio wave propagation analysis using the radio wave coverage area calculation point B2 as the transmission point, and calculates the remaining base station candidate points A1 to A2 stored in the base station candidate point storage unit 4. M Then, the radio wave coverage area calculation point B3 is calculated. N Similarly, radio wave propagation analysis is performed sequentially up to n -A m ) is found.

[0022] Note that n represents 1 to N, and m represents 1 to M. However, n and m representing propagation loss do not necessarily represent all of 1 to N or all of 1 to M. In particular, the base station candidate points A1 to A MIn this case, the base station candidate points A1 to A2 are deleted from the base station candidate point storage unit 4 by the base station selection unit 8. M Therefore, the radio wave coverage area calculation points B1 to B N Base station candidate points A1 to A2 for radio wave propagation analysis M The number of base station candidate points A1 to A M The number of becomes 0.

[0023] The base station selector 8 calculates the propagation loss (B n -A m ) and the propagation loss (B n -A m ) is sequentially compared with a predetermined threshold, and base station candidate points with propagation losses equal to or greater than the threshold are deleted from the base station candidate point storage unit 4. Propagation loss (B n -A m ) is the base station candidate point A where the propagation loss is greater than the threshold m is the radio wave coverage area calculation point B n This means that communication with base station candidate point A is not possible. m This means that it will not be possible to build a coverage area.

[0024] For the base station candidate points that are not deleted from the base station candidate point storage unit 4 by the base station selection unit 8, the propagation loss calculation unit 7 continues to perform radio wave propagation analysis. When there are no more base station candidate points stored in the base station candidate point storage unit 4 as a result of deleting the base station candidate points with propagation loss equal to or greater than the threshold value from the base station candidate point storage unit 4, the base station selection unit 8 determines the base station candidate point to be last deleted from the base station candidate point storage unit 4, that is, the base station candidate point immediately before all base station candidate points are deleted, as the selection result.

[0025] In other words, the base station candidate points that remain after being deleted by the base station selection unit 8 until all base station candidate points no longer exist are used as the selection results. The station location determination unit 9 determines the base station candidate point selected by the base station selection unit 8 as the station location where the base station is to be located. The determined station location is output to an output unit (not shown) as station location information.

[0026] In other words, the propagation loss calculation unit 7 calculates the propagation loss of all the base station candidate points A1 to A2 set in the base station candidate area 30, with the radio wave coverage area calculation point B1, which is closest in straight line distance from the reference point of the base station candidate area 30, as the transmission point. M A radio wave propagation analysis was carried out with each receiving point to calculate the propagation loss (B1-A m ) and calculate the remaining radio wave coverage areas B2 to B N The radio wave coverage area calculation points B2 to B3 are arranged in descending order of the distance from the base station candidate area 30 to the reference point. N is used as a transmitting point, and a radio wave propagation analysis is performed with each of the remaining base station candidate points, excluding the base station candidate points deleted by the base station selection unit 8, as a receiving point to obtain the propagation loss.

[0027] Therefore, the propagation loss calculation unit 7 calculates the distance between the base station candidate points A1 to A2 and the radio wave coverage area calculation point B1, which is closest in straight line distance from the reference point of the base station candidate area 30. M Since the propagation loss for each is calculated, there is no risk of eliminating the optimum station location candidate. Moreover, the propagation loss calculation unit 7 calculates the radio wave coverage area from the following points B2 to B N On the other hand, base station candidate points with propagation losses equal to or greater than the threshold are deleted and the propagation loss for each base station candidate point is calculated, so the amount of calculation for radio wave propagation analysis in propagation loss calculation unit 7 is reduced.

[0028] Next, a processing procedure for station placement design by the station placement design device according to the first embodiment will be described with reference to FIG. As an initial setting, the area setting unit 2 sets a set area 100 from the map information stored in the map information storage unit 1, and the station location candidate point setting unit 3 sets the base station candidate points A1 to A2 in the base station candidate area 30 in the set area 100 set by the area setting unit 2. M and base station candidate points A1 to A MThe base station candidate point storage unit 4 stores the base station candidate point, and the radio wave arrival area calculation point setting unit 5 sets the radio wave arrival area calculation points B1 to B2 within the cover area 40 in the setting area 100 set by the area setting unit 2. N Set the radio wave coverage area calculation points B1 to B N is stored in the radio wave coverage area calculation point storage unit 6.

[0029] In step ST1, the propagation loss calculation unit 7 calculates the radio wave coverage area at point B. n is determined as the radio wave coverage area calculation point B1, which is closest in straight line distance from the reference point of the base station candidate area 30, The radio wave arrival area calculation points B1 to B2 stored in the arrival area calculation point storage unit 6 N The radio wave coverage area calculation point B1 is read out from the above, and the process proceeds to step ST2. In step ST2, the propagation loss calculation unit 7 calculates the base station candidate point A m is defined as a base station candidate point A1, and the base station candidate points A1 to A M The base station candidate point A1 is read out from the list, and the process proceeds to step ST3.

[0030] In step ST3, the propagation loss calculation unit 7 performs a radio wave propagation analysis with the radio wave coverage area calculation point B1 as the transmission point and the base station candidate point A1 as the reception point, and calculates the propagation loss (B1-A1). Then, proceed to step ST4. In step ST4, the base station selection unit 8 compares the propagation loss (B1-A1) with a threshold value. If the propagation loss (B1-A1) is greater than or equal to the threshold, the base station candidate point A1 is excluded. Base station candidate points A1 to A2 stored in the station candidate point storage unit 4 M The base station candidate point A1 is deleted from the

[0031] In step ST5, if m indicating a base station candidate point is less than M, the process proceeds to step ST6, and if m is M, the process proceeds to step ST7. Since m is currently 1, the process proceeds to step ST6, where the propagation loss calculation unit 7 sets m to m+1, that is, 2, and sets the base station candidate point A2 as the next evaluation candidate. When the base station candidate point A2 is determined as the next evaluation candidate, the process proceeds to step ST3, step ST4, and step ST5, where the propagation loss calculation unit 7 calculates the propagation loss (B1-A2) between the radio wave coverage area calculation point B1 and the base station candidate point A2, and the base station selection unit 8 selects the base station candidate point A2 as the next evaluation candidate. The process from step ST3 to step ST5 is repeated until m becomes M, and all base station candidate points A1 to A2 for the radio wave coverage area calculation point B1 are excluded. M When the evaluation is completed, the process proceeds to step ST7.

[0032] For the radio wave coverage area calculation point B1, all base station candidate points A1 to A M Step ST3 for processing each of the base station candidate points is performed by calculating the first radio wave coverage area calculation point B1 that is closest in straight line distance from the reference point of the base station candidate area 30 and the plurality of base station candidate points A1 to A2 that can be placed in the base station candidate area 30. M Radio wave propagation analysis is performed for each of the base station candidate points A1 to A2. M This is the first radio wave propagation analysis step to obtain the propagation loss for each. In the first radio wave propagation analysis step, all base station candidate points A1 to A M Since radio wave propagation analysis is performed and propagation loss is obtained, base station candidate points A1 to A M Therefore, there is no risk that the optimum station position candidate will be removed from the list.

[0033] For the radio wave coverage area calculation point B1, all base station candidate points A1 to A M Step ST4 processes the propagation loss, which is the result of the radio wave propagation analysis for each of the base stations, and is a first station location selection step in which the propagation losses obtained in the first radio wave propagation analysis step are sequentially compared with a threshold value, and base station candidate points whose propagation loss is equal to or greater than the threshold value are excluded.

[0034] In step ST7, the propagation loss calculation unit 7 determines whether or not all base station candidate points stored in the base station candidate point storage unit 4 have been deleted. If the number of base station candidate points stored in the base station candidate point storage unit 4 is not 0 and remains, the process proceeds to step ST9 on the condition that n in step ST8 is less than N; if all base station candidate points stored in the base station candidate point storage unit 4 have been deleted, that is, are 0, the process proceeds to step ST10.

[0035] In step ST9, if n indicating the radio wave coverage area calculation point is less than N, n is set to n+1, that is, 2, and the process returns to step ST2. For the second radio wave coverage area calculation point B2, steps ST3 → ST4 → ST5 → ST6 → ST3 → . . . step ST5 are performed, and the remaining base station candidate points A1 to A2 for the second radio wave coverage area calculation point B2 are M Each evaluation is repeated until it is completed, then proceed to step ST7, step ST8, and step ST9, where n is set to n+1 in step ST9, and the same processing is performed for the third radio wave coverage area calculation point B3 as for the second radio wave coverage area calculation point B2.

[0036] Radio wave coverage area calculation points B1~B N In step ST4 for each base station candidate point, the base station candidate point that has been excluded because the propagation loss is equal to or greater than the threshold is excluded from the station placement candidates. Second and subsequent radio wave coverage area calculation points B2~B N In step ST6 for each, the previous radio wave coverage area calculation points B1 to B N-1 If the base station candidate point is excluded by the base station selection unit 8 in step ST4 for each, 1 is added to m up to the base station candidate point that has not been excluded, and the process returns to step ST3. Second and subsequent radio wave coverage area calculation points B2~B N In step ST3 for each, the previous radio wave coverage area calculation points B1 to B N-1 The base station candidate points excluded by the base station selection unit 8 in step ST4 for each are excluded from the base station candidate points for which propagation loss is calculated.

[0037] Second and subsequent radio wave coverage area calculation points B2~B N Step ST3 is performed for each of the remaining base station candidate points excluding the base station candidate points excluded in step ST4. N This is a second or subsequent radio wave propagation analysis step in which radio wave propagation analysis is sequentially performed for each of the remaining base station candidate points to obtain the propagation loss for each of the remaining base station candidate points.

[0038] Second and subsequent radio wave coverage area calculation points B2~B N Step ST4 sequentially processes the propagation loss, which is the result of radio wave propagation analysis for each of the remaining base station candidate points, and is a second or subsequent station selection step that sequentially compares the propagation loss obtained in the second or subsequent radio wave propagation analysis steps with a threshold value and excludes base station candidate points whose propagation loss is equal to or greater than the threshold value. In the first and second and subsequent station selection steps, base station candidate points with propagation loss equal to or greater than a threshold are excluded. Therefore, in the second and subsequent radio wave propagation analysis steps, radio wave propagation analysis is not performed on the excluded base station candidate points, but is performed on the remaining base station candidate points, thereby reducing the amount of calculation required for radio wave propagation analysis.

[0039] In step ST7, if the propagation loss calculation unit 7 determines that all base station candidate points stored in the base station candidate point storage unit 4 have been deleted, that is, that the number is 0, the process proceeds to step ST10. In step ST10, the base station selection unit 8 determines the base station candidate point immediately before deleting all the base station candidate points as the selection result, and the station location determination unit 9 determines the base station candidate point determined as the selection result by the base station selection unit 8 as the station location where the base station will be located. The determined station location is output to an output unit as station location information.

[0040] In step ST7, for example, the Nth radio wave coverage area calculation point B NWhen the radio wave propagation analysis is performed for each remaining base station candidate point and it is determined that all base station candidate points have been deleted and the number of remaining base station candidate points is determined to be 0, in step ST10, the N-1th radio wave coverage area calculation point B N-1 The remaining base station candidate points after radio wave propagation analysis are determined as the station locations where the base stations will be located.

[0041] Nth radio wave coverage area calculation point B N In the process for the above, all base station candidate points are deleted, that is, the propagation loss for all base station candidate points is equal to or greater than the threshold, and the Nth radio wave coverage area calculation point B N This means that communication with all base station candidate points is not possible. N Therefore, it is not possible to construct a coverage area by any of the base station candidate points up to this range.

[0042] Meanwhile, the N-1 radio wave coverage area calculation point B N-1 In the process of N-1 This means that communication with the N-1st radio wave coverage area calculation point B is possible. N-1 Therefore, the coverage area can be constructed using the remaining base station candidate points up to the range. These remaining base station candidate points can form a coverage area with the largest range in area 40 where a coverage area is desired to be formed. Step ST10 is a station placement selection result step in which the base station candidate points remaining without being deleted immediately before all base station candidate points are deleted are taken as the station placement selection result.

[0043] The station location design device according to the first embodiment, which includes a map information storage unit 1, an area setting unit 2, a station location candidate point setting unit 3, a base station candidate point storage unit 4, a radio wave arrival area calculation point setting unit 5, a radio wave arrival area calculation point storage unit 6, a propagation loss calculation unit 7, a base station selection unit 8, and a station location determination unit 9, is realized by a computer hardware configuration, and as shown in FIG. 5, includes a CPU (Central Processing Unit) 10A, a large-capacity semiconductor memory (RAM: Random Access Memory) 10B, a storage device (ROM: Read only memory) 10C such as a hard disk device or a nonvolatile storage device such as an SSD device, an input interface unit 10D, an output interface unit 10E, and a signal path (bus) 10F.

[0044] The CPU 10A controls and manages the RAM 10B, the ROM 10C, the input interface unit 10D, and the output interface unit 10E. The CPU 10A loads the programs stored in the ROM 10C into the RAM 10B, and executes various processes based on the programs loaded into the RAM 10B.

[0045] The map information storage unit 1, the base station candidate point storage unit 4, and the radio wave coverage area calculation point storage unit 6 are configured as part of the RAM 10B. The area setting unit 2, the station location candidate point setting unit 3, the radio wave coverage area calculation point setting unit 5, the propagation loss calculation unit 7, the base station selection unit 8, and the station location determination unit 9 are each components that represent functions executed by the CPU 10A based on a program stored in the ROM 10C and loaded into the RAM 10B. The signal path 1F is a bus that interconnects the CPU 10A, RAM 10B, ROM 10C, input interface unit 10D, and output interface unit 10E.

[0046] The program stored in the ROM 10C and executed by the CPU 10A includes a first radio wave propagation analysis procedure for sequentially performing radio wave propagation analysis for a first radio wave coverage area calculation point that is closest in straight-line distance from a reference point of the base station candidate area and for each of a plurality of base station candidate points that can be arranged in the base station candidate area, and obtaining a propagation loss for each of the plurality of base station candidate points; a first station placement selection procedure for sequentially comparing the propagation losses sequentially obtained in the first radio wave propagation analysis procedure with a threshold and excluding base station candidate points whose propagation loss is equal to or greater than the threshold; The method comprises a second and subsequent radio wave propagation analysis procedure in which radio wave propagation analysis is performed sequentially for each of the remaining base station candidate points excluding the base station candidate points excluded by the station selection procedure, and the propagation loss for each of the base station candidate points analyzed for radio wave propagation is obtained; a second and subsequent station selection procedure in which the propagation loss obtained sequentially in each of the second and subsequent radio wave propagation analysis procedures is compared sequentially with a threshold value, and base station candidate points whose propagation loss is equal to or greater than the threshold value are excluded; and a station selection result procedure in which the base station candidate points remaining without being deleted immediately before all base station candidate points are deleted are used as the station selection result.

[0047] In the station placement design device according to the first embodiment, the propagation loss calculation unit 7 calculates the radio wave coverage area calculation point B1 that is closest in straight-line distance from the reference point of the base station candidate area 30 and the plurality of base station candidate points A1 to A2 stored in the base station candidate point storage unit 4. M The radio wave propagation analysis is sequentially performed for each of the remaining radio wave arrival area calculation points B2 to B N The base station selection unit 8 sequentially performs radio wave propagation analysis between each of the remaining base station candidate points stored in the base station candidate point storage unit 4, and the radio wave propagation analysis is performed by the propagation loss calculation unit 7, and the base station selection unit 8 sequentially compares the received propagation losses with a threshold value, and deletes the base station candidate points whose propagation losses are equal to or greater than the threshold value from the base station candidate point storage unit 4. The base station candidate points immediately before all the base station candidate points stored in the base station candidate point storage unit 4 are deleted are regarded as the selection result. Therefore, the base station candidate points A1 to A2 stored in the base station candidate point storage unit 4 are selected. MFor all base station candidate points, the propagation loss is calculated for the radio wave coverage area calculation point B1 that is closest in straight line distance from the reference point of the base station candidate area 30, so there is no risk of the optimum station location candidate being eliminated, and furthermore, base station candidate points with propagation loss equal to or greater than the threshold are eliminated, and the propagation loss for each base station candidate point is calculated, so the amount of calculation for radio wave propagation analysis in the propagation loss calculation unit 7 is reduced.

[0048] In the station placement design device according to the first embodiment, as shown in FIG. 3, an area 40 where a cover area is to be constructed is located in one direction, and radio wave coverage area calculation points B1 to B N However, if the area 40 exists in multiple directions and the radio wave coverage area calculation points B1 to B N The station placement design apparatus according to the first embodiment can also be applied to an example in which the antennas are installed in multiple directions or in parallel.

[0049] That is, the radio wave coverage area calculation points B1 to B2 are set in multiple directions or in parallel. N For each of these, the radio wave coverage area calculation points B1 to B2 are set in one direction. N There are multiple base station candidate points A1 to A M The propagation loss calculation unit 7 and the base station selection unit 8 can perform similar processing, in which radio wave propagation analysis is performed for each of them to calculate the propagation loss, and base station candidate points with propagation loss equal to or greater than a threshold are deleted from the base station candidate point storage unit 4, and the base station candidate point immediately before all base station candidate points are deleted is used as the selection result.

[0050] Embodiment 2 The station placement design device according to the second embodiment will be described with reference to FIG. The station location design device according to the second embodiment selects a station from a plurality of base station candidate points by taking into consideration not only the location of the base station candidate point in the base station candidate area 30 but also the directivity of the base station antenna (hereinafter referred to as the antenna) or the installation direction of the antenna. That is, the station location design device according to the second embodiment treats different base station candidate points as different base station candidate points even if the placement positions in the base station candidate area 30 are the same, if the directivities or directions of the antennas are different.

[0051] As shown in FIG. 6 , the station location design device according to the second embodiment includes a map information storage unit 1, an area setting unit 2, a station location candidate point setting unit 3a, a base station candidate point storage unit 4a, a radio wave arrival area calculation point setting unit 5, a radio wave arrival area calculation point storage unit 6, a propagation loss calculation unit 7a, a base station selection unit 8, and a station location determination unit 9. In FIG. 6, the same reference numerals as in FIG. 1 indicate the same or corresponding parts.

[0052] The map information storage unit 1, the area setting unit 2, the radio wave arrival area calculation point setting unit 5, the radio wave arrival area calculation point storage unit 6, the base station selection unit 8, and the station location determination unit 9 are the same as the map information storage unit 1, the area setting unit 2, the radio wave arrival area calculation point setting unit 5, the radio wave arrival area calculation point storage unit 6, the base station selection unit 8, and the station location determination unit 9 in the station location design device according to embodiment 1, and therefore will not be described again.

[0053] The station location candidate point setting unit 3a sets the base station candidate points A1 to A2 that are known in advance in the base station candidate area 30 indicated by the area setting unit 2. M are arranged and set, and the base station candidate points A1 to A M At least one of the directivity or direction of the antenna that can be arranged at each of the base station candidate points A1 to A2 (hereinafter referred to as the antenna propagation characteristics) is set, and information indicating the antenna propagation characteristics is linked to the position information indicating the arrangement position. M The base station candidate point storage unit 4a stores information indicating the above. The station location candidate point setting unit 3a sets the same location as a different base station candidate point when the propagation characteristics of the antenna are different.

[0054] The propagation loss calculation unit 7a calculates the propagation loss of the radio wave arrival area calculation points B1 to B2 stored in the radio wave arrival area calculation point storage unit 6. Nare read out in order of closest straight-line distance from the reference point of the base station candidate area 30, and the read out radio wave coverage area calculation points B1 to B N is used as a transmission point, and the base station candidate points A1 to A2 stored in the base station candidate point storage unit 4a are M A radio wave propagation analysis was performed with the receiving point at n -A m ) is calculated. The propagation loss calculation unit 7a treats base station candidate points that have different antenna propagation characteristics as different base station candidate points even if they are located at the same position. The propagation loss calculation unit 7a calculates the propagation loss of the base station candidate points A1 to A M The propagation characteristics of the antenna are added to the placement position, and a radio wave propagation analysis is performed to calculate the propagation loss.

[0055] If an antenna has directionality, the propagation characteristics will change depending on the installation direction and directivity of the antenna even if the antenna is located at the same point. However, the propagation loss calculation unit 7a treats base station candidate points with different antenna propagation characteristics as separate base station candidate points even if the placement location is the same, and calculates the propagation loss accordingly, so that it is possible to select a base station when antennas with different antenna propagation characteristics are placed at the same placement location.

[0056] The procedure for selecting a station in the station location design device according to the second embodiment is substantially the same as the procedure for selecting a station in the station location design device according to the second embodiment, except that base station candidate points that have the same placement location but different antenna propagation characteristics are treated as different base station candidate points. The station location design apparatus according to the second embodiment has the same effects as the station location design apparatus according to the first embodiment, and can also determine station locations where base stations are to be located, taking into account the propagation characteristics of antennas.

[0057] Embodiment 3 The station placement design device according to the third embodiment will be described with reference to FIG. The station placement design device according to the third embodiment receives line-of-sight environment information and calculates second and subsequent radio wave coverage areas B2 to B NThe radio wave propagation analysis for the remaining base station candidate points for the set number of radio wave coverage area calculation points is omitted, and the radio wave propagation analysis is performed for the remaining base station candidate points for the radio wave coverage area calculation points after the set number.

[0058] The line-of-sight environment information indicates information on the line-of-sight environment in which radio waves traveling straight from the base station candidate point, in embodiment 3, the reference point of the base station candidate area 30, are estimated to reach the radio wave coverage area calculation point without being blocked by buildings, etc. In a line-of-sight environment, propagation loss tends to be close to that in free space. Therefore, according to the theoretical value of propagation loss, it is possible to predict to some extent the points where propagation loss will exceed the threshold. Therefore, radio wave propagation analysis for the remaining base station candidate points for the radio wave coverage area calculation points immediately before the radio wave coverage area calculation points where propagation loss is predicted to exceed the threshold can be omitted.

[0059] The station placement design device of embodiment 3 performs radio wave propagation analysis on the remaining base station candidate points for the radio wave coverage area calculation point immediately after the set number based on the line-of-sight environment information, that is, the radio wave coverage area calculation point where the propagation loss is predicted to exceed a threshold, and when the propagation losses at the remaining base station candidate points are all equal to or greater than the threshold, performs radio wave propagation analysis on the remaining base station candidate points for the radio wave coverage area calculation point immediately before the radio wave coverage area calculation point where the propagation loss is predicted to exceed the threshold, and then performs radio wave propagation analysis on the remaining base station candidate points for the radio wave coverage area calculation point one step before that until a base station candidate point where the propagation loss is less than the threshold appears. The station placement design device according to the third embodiment selects a base station candidate point where the propagation loss is less than a threshold as a placement station for placing the base station.

[0060] As shown in FIG. 7 , the station location design device according to the third embodiment includes a map information storage unit 1, an area setting unit 2, a station location candidate point setting unit 3, a base station candidate point storage unit 4, a radio wave arrival area calculation point setting unit 5, a radio wave arrival area calculation point storage unit 6, a propagation loss calculation unit 7b, a base station selection unit 8a, and a station location determination unit 9. In FIG. 7, the same reference numerals as in FIG. 1 indicate the same or corresponding parts.

[0061] The map information storage unit 1, the area setting unit 2, the station location candidate point setting unit 3, the base station candidate point storage unit 4, the radio wave arrival area calculation point setting unit 5, the radio wave arrival area calculation point storage unit 6, and the station location determination unit 9 are the same as the map information storage unit 1, the area setting unit 2, the station location candidate point setting unit 3, the base station candidate point storage unit 4, the radio wave arrival area calculation point setting unit 5, the radio wave arrival area calculation point storage unit 6, and the station location determination unit 9 in the station location design device according to embodiment 1, and therefore will not be described again.

[0062] The propagation loss calculation unit 7b calculates the radio wave arrival area calculation point B1 stored in the radio wave arrival area calculation point storage unit 6 and the second and subsequent radio wave arrival area calculation points B2 to B3 until the line-of-sight environment information indicates a line-of-sight environment. n1 The radio wave propagation analysis is carried out with the read radio wave arrival area calculation point as the transmission point and each of the base station candidate points stored in the base station candidate point storage unit 4 as the reception point, and the propagation loss for each is calculated.

[0063] For example, when a line-of-sight environment is indicated for the second radio wave arrival area calculation point B2, the propagation loss calculation unit 7b sets the first radio wave arrival area calculation point B1, which is closest in straight-line distance from the reference point of the base station candidate area 30, as the transmission point, and calculates the line-of-sight environment for all base station candidate points A1 to A2 stored in the base station candidate point storage unit 4. M A radio wave propagation analysis is carried out with each of these as receiving points, and the propagation loss for each is calculated.

[0064] The propagation loss calculation unit 7b omits performing radio wave propagation analysis for the remaining base station candidate points for the radio wave coverage area calculation point immediately preceding the radio wave coverage area calculation point where the propagation loss is predicted to exceed the threshold from the second radio wave coverage area calculation point B2, which indicates a line-of-sight environment. In a line-of-sight environment, propagation loss tends to be close to that in free space, and the propagation loss for each base station candidate point at a radio wave coverage area calculation point within the line-of-sight environment can be estimated using the straight-line distance between the radio wave coverage area calculation point and the base station candidate point.In addition, by indicating that the line-of-sight environment information does not indicate a line-of-sight environment, it is possible to predict the radio wave coverage area calculation point where the propagation loss will exceed a threshold.

[0065] The propagation loss calculation unit 7b resumes the radio wave propagation analysis, setting the radio wave arrival area calculation point where the propagation loss is predicted to exceed the threshold as the transmission point, and setting each of the remaining base station candidate points stored in the base station candidate point storage unit 4 as the reception point, and calculates the propagation loss for each. The propagation loss calculation unit 7b continues to calculate the propagation loss for each of the remaining base station candidate points stored in the base station candidate point storage unit 4, sequentially for radio wave coverage area calculation points in a direction away from the radio wave coverage area calculation point where the propagation loss is predicted to exceed the threshold, until there are no more base station candidate points stored in the base station candidate point storage unit 4.

[0066] When there are no more base station candidate points stored in the base station candidate point storage unit 4 as a result of deleting the base station candidate points with propagation loss equal to or greater than the threshold value from the base station candidate point storage unit 4, the base station selection unit 8a determines the base station candidate point to be last deleted from the base station candidate point storage unit 4, that is, the base station candidate point immediately before all base station candidate points are deleted, as the selection result. As an example, the line-of-sight environment is shown for the second radio wave coverage area calculation point B2, but the line-of-sight environment is shown for the second and subsequent radio wave coverage area calculation points B2 to B n1 Any of the radio wave coverage area calculation points may be used, and the same processing is performed even if there are multiple radio wave coverage area calculation points that indicate a line-of-sight environment.

[0067] Incidentally, the propagation loss calculation unit 7b resumes the radio wave propagation analysis with the radio wave arrival area calculation point where the propagation loss is predicted to exceed the threshold as the transmission point and each of the remaining base station candidate points stored in the base station candidate point storage unit 4 as the reception point, and calculates the propagation loss for each. As a result, there are cases where the propagation losses for all of the remaining base station candidate points are equal to or greater than the threshold due to the influence of a multipath environment, etc.

[0068] In this case, the propagation loss calculation unit 7b reads out from the radio wave coverage area calculation point storage unit 6 a radio wave coverage area calculation point in a direction where the straight-line distance from the reference point of the base station candidate area 30 is closer to the radio wave coverage area calculation point where the propagation loss is predicted to exceed the threshold, and performs radio wave propagation analysis on the remaining base station candidate points stored in the base station candidate point storage unit 4, excluding the base station candidate points to be deleted as a result of calculating the propagation loss for the base station candidate points at the second radio wave coverage area calculation point B2, which indicates a line-of-sight environment.

[0069] The propagation loss calculation unit 7b performs radio wave propagation analysis on the remaining base station candidate points for the previous radio wave coverage area calculation point one by one until a base station candidate point appears at which the propagation loss is less than the threshold value. The base station selection unit 8a performs radio wave propagation analysis on the remaining base station candidate points for the radio wave coverage area calculation point in the direction of decreasing straight-line distance from the reference point of the base station candidate area 30 using the propagation loss calculation unit 7b, and selects the first base station candidate point that appears with a propagation loss less than the threshold as the selection result.

[0070] The station location design device according to embodiment 3 has the same effects as the station location design device according to embodiment 1, and in addition, when the propagation loss calculation unit 7b receives line-of-sight environment information, it omits performing radio wave propagation analysis on the remaining base station candidate points for the radio wave coverage area calculation point immediately preceding the radio wave coverage area calculation point where the propagation loss is predicted to exceed the threshold from the radio wave coverage area calculation point indicating the line-of-sight environment, thereby further reducing the amount of calculation for radio wave propagation analysis in the propagation loss calculation unit 7.

[0071] Furthermore, in the station placement design device according to embodiment 3, when the propagation loss calculation unit 7b performs radio wave propagation analysis on the remaining base station candidate points for a radio wave coverage area calculation point where the propagation loss is predicted to exceed the threshold, and the propagation loss at all of the remaining base station candidate points is equal to or greater than the threshold, the propagation loss calculation unit 7b performs radio wave propagation analysis on the remaining base station candidate points for the radio wave coverage area calculation point immediately preceding the radio wave coverage area calculation point where the propagation loss is predicted to exceed the threshold, and then performs radio wave propagation analysis on the remaining base station candidate points for the radio wave coverage area calculation point immediately preceding the radio wave coverage area calculation point where the propagation loss is predicted to exceed the threshold, one by one, until a base station candidate point where the propagation loss is less than the threshold appears, and the base station selection unit 8a selects the base station candidate point where the propagation loss obtained first by the propagation loss calculation unit 7b is less than the threshold as the selection result, and therefore the base station candidate point where the largest coverage area can be obtained can be the selection result for the station placement.

[0072] In addition, in the station location design device according to embodiment 3, as shown in the station location design device according to embodiment 2, even if the placement positions in base station candidate area 30 are the same, if the antenna directivities or antenna directions are different, they may be treated as different base station candidate points, and the same procedure as shown in the station location design device according to embodiment 2 may also be included.

[0073] It should be noted that the embodiments may be freely combined, or any of the components in each embodiment may be modified, or any of the components in each embodiment may be omitted. [Industrial Applicability]

[0074] The station location design device according to the present disclosure is suitable for use as a station location design device that selects the location of base stations in a mobile communication system. [Explanation of symbols]

[0075] 1 map information storage unit, 2 area setting unit, 3, 3a station location candidate point setting unit, 4, 4a base station candidate point storage unit, 5 radio wave arrival area calculation point setting unit, 6 radio wave arrival area calculation point storage unit, 7, 7a, 7b propagation loss calculation unit, 8, 8a base station selection unit, 9 station location determination unit, 30 Base station candidate area, 40 Area where you want to build coverage area, A1~A M Base station candidate points, B1~B N Radio wave coverage area calculation point.

Claims

1. a base station candidate point storage unit that stores a plurality of base station candidate points that can be arranged in a base station candidate area in a set region based on map information; a radio wave arrival area calculation point storage unit that stores a plurality of radio wave arrival area calculation points that are set in an area where a cover area is desired to be established in the set area; a propagation loss calculation unit that is stored in the radio wave arrival area calculation point storage unit, and that sequentially performs radio wave propagation analysis between the radio wave arrival area calculation point that is closest in straight-line distance from a reference point of the base station candidate area and each of the plurality of base station candidate points stored in the base station candidate point storage unit, and sequentially performs radio wave propagation analysis between each of the remaining radio wave arrival area calculation points stored in the radio wave arrival area calculation point storage unit and each of the remaining base station candidate points stored in the base station candidate point storage unit; a base station selection unit that performs radio wave propagation analysis by the propagation loss calculation unit, sequentially compares the received propagation losses with a threshold, deletes base station candidate points whose propagation losses are equal to or greater than the threshold from the base station candidate point storage unit, and determines the base station candidate points stored in the base station candidate point storage unit immediately before all the base station candidate points are deleted as the selection result; A station placement design device comprising:

2. an area in which a cover area is to be constructed in the set region exists in one direction; the plurality of radio wave arrival area calculation points stored in the radio wave arrival area calculation point storage unit are radio wave arrival area calculation points set in one direction; The station placement design device according to claim 1 .

3. an area in which a cover area is to be constructed in the set region exists in a plurality of directions; The plurality of radio wave arrival area calculation points stored in the radio wave arrival area calculation point storage unit are radio wave arrival area calculation points set in a plurality of directions. The station placement design device according to claim 1 .

4. 4. The station location design device according to claim 1, wherein the base station candidate points stored in the base station candidate point storage unit are linked to their placement positions in the base station candidate area by antenna directivity or antenna installation direction, and are considered to be different base station candidate points when the placement positions are the same but the antenna directivity or antenna direction is different.

5. 4. The station location design device according to claim 1, wherein, when the propagation loss calculation unit receives line-of-sight environment information, it omits performing radio wave propagation analysis for remaining base station candidate points for a radio wave coverage area calculation point immediately preceding a radio wave coverage area calculation point where the propagation loss is predicted to exceed a threshold.

6. 6. The station location design device according to claim 5, wherein, when the propagation losses at all of the remaining base station candidate points are equal to or greater than the threshold as a result of performing radio wave propagation analysis on the remaining base station candidate points for a radio wave arrival area calculation point where the propagation loss is predicted to exceed the threshold, the propagation loss calculation unit performs radio wave propagation analysis on the remaining base station candidate points for a radio wave arrival area calculation point immediately preceding the radio wave arrival area calculation point where the propagation loss is predicted to exceed the threshold, and then performs radio wave propagation analysis on the remaining base station candidate points for the radio wave arrival area calculation point immediately preceding the radio wave arrival area calculation point where the propagation loss is predicted to exceed the threshold, one by one, until a base station candidate point appears where the propagation loss is less than the threshold.

7. A station location design method for selecting a location of a base station by a station location design device including a propagation loss calculation unit and a base station selection unit, a first radio wave propagation analysis step in which the propagation loss calculation unit sequentially performs radio wave propagation analysis for a first radio wave coverage area calculation point that is closest in straight-line distance from a reference point in the base station candidate area and for each of a plurality of base station candidate points that can be arranged in the base station candidate area, and obtains a propagation loss for each of the plurality of base station candidate points; a first station location selection step in which the propagation loss calculation unit sequentially compares the propagation losses sequentially obtained in the first radio wave propagation analysis step with a threshold, and excludes base station candidate points whose propagation losses are equal to or greater than the threshold; a second or subsequent radio wave propagation analysis step in which the propagation loss calculation unit sequentially performs radio wave propagation analysis for each of the second or subsequent radio wave coverage area calculation points and each of the remaining base station candidate points excluding the base station candidate points excluded in the station selection step, and obtains a propagation loss for each of the base station candidate points subjected to the radio wave propagation analysis; a second or subsequent station selection step in which the base station selection unit sequentially compares the propagation loss obtained in each of the second or subsequent radio wave propagation analysis steps with a threshold, and excludes base station candidate points whose propagation loss is equal to or greater than the threshold; a station placement selection result step in which the base station selection unit determines a base station candidate point that remains undeleted immediately before all base station candidate points are deleted by the base station selection unit as a station placement selection result; A station placement design method comprising:

8. a first radio wave propagation analysis procedure for sequentially performing radio wave propagation analysis for a first radio wave coverage area calculation point that is closest in straight-line distance from a reference point in a base station candidate area and for each of a plurality of base station candidate points that can be arranged in the base station candidate area, and obtaining a propagation loss for each of the plurality of base station candidate points; a first station location selection procedure for sequentially comparing the propagation losses sequentially obtained in the first radio wave propagation analysis procedure with a threshold, and excluding base station candidate points whose propagation losses are equal to or greater than the threshold; a second or subsequent radio wave propagation analysis procedure for sequentially performing radio wave propagation analysis for each of the second or subsequent radio wave coverage area calculation points and each of the remaining base station candidate points excluding the base station candidate points excluded by the station selection procedure, and obtaining a propagation loss for each of the base station candidate points subjected to the radio wave propagation analysis; a second or subsequent station selection procedure for sequentially comparing the propagation loss obtained in each of the second or subsequent radio wave propagation analysis procedures with a threshold, and excluding base station candidate points whose propagation loss is equal to or greater than the threshold; a station placement selection result procedure in which the base station candidate points remaining without being deleted immediately before all base station candidate points are deleted are set as the station placement selection result; A station placement design program that causes a computer to execute the above.

9. a first radio wave propagation analysis procedure for sequentially performing radio wave propagation analysis for a first radio wave coverage area calculation point that is closest in straight-line distance from a reference point in a base station candidate area and for each of a plurality of base station candidate points that can be arranged in the base station candidate area, and obtaining a propagation loss for each of the plurality of base station candidate points; a first station location selection procedure for sequentially comparing the propagation losses sequentially obtained in the first radio wave propagation analysis procedure with a threshold, and excluding base station candidate points whose propagation losses are equal to or greater than the threshold; a second or subsequent radio wave propagation analysis procedure for sequentially performing radio wave propagation analysis for each of the second or subsequent radio wave coverage area calculation points and each of the remaining base station candidate points excluding the base station candidate points excluded by the station selection procedure, and obtaining a propagation loss for each of the base station candidate points subjected to the radio wave propagation analysis; a second or subsequent station selection procedure for sequentially comparing the propagation loss obtained in each of the second or subsequent radio wave propagation analysis procedures with a threshold, and excluding base station candidate points whose propagation loss is equal to or greater than the threshold; a station placement selection result procedure in which the base station candidate points remaining without being deleted immediately before all base station candidate points are deleted are set as the station placement selection result; A recording medium storing a program that causes a computer to execute the above.

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