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

Abstract

A station placement design device comprising: a propagation loss calculation unit (7) that sequentially performs radio wave propagation analysis between a radio wave arrival region calculation point stored in a radio wave arrival region calculation point storage unit (5) and having a closest linear 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 region calculation points stored in the radio wave arrival region 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 a threshold value with propagation losses sequentially received after radio wave propagation analysis by the propagation loss calculation unit (7), deletes a base station candidate point at which the propagation loss is equal to or greater than the threshold value from the base station candidate point storage unit (4), and uses, as a selection result, the base station candidate point remaining immediately before all of the base station candidate points stored in the base station candidate point storage unit (4) have been deleted.

Description

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

[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.

[0002] Patent Literature 1 discloses a station location design device that can calculate a position where propagation loss is minimized without increasing the amount of calculation in station location design that determines the position where a base station is to be located. The station location design device disclosed in Patent Literature 1 includes a candidate setting unit that determines candidates for the position where the base station is to be located in an area indicating the layout of buildings, an area dividing unit that divides the area into multiple meshes, an area calculation unit that calculates an integrated value (line-of-sight area) of the areas of the meshes determined based on the positional relationships between the candidates, the buildings, and the centers of the meshes, 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, and a position selection unit 170 that selects the candidate with the largest integrated value of the areas of the meshes that indicate propagation loss less than the threshold.

[0003] JP 2011-234091 A

[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.

[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.

[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.

[0008] FIG. 1 is a block diagram showing a station placement design device according to a first embodiment. FIG. 2 is a diagram showing an example of an area acquired from map information, and a base station candidate area and a cover area within the area. FIG. 3 is a diagram showing an example of base station candidate points and radio wave arrival area calculation points set in FIG. 2. FIG. 4 is a flowchart showing an outline of a processing procedure for station placement design by a station placement design device according to a first embodiment. FIG. 5 is a configuration diagram showing a hardware configuration of a station placement design device according to a first embodiment. FIG. 6 is a block diagram showing a station placement design device according to a second embodiment. FIG. 7 is a block diagram showing a station placement design device according to a third embodiment.

[0009] Embodiment 1. A station location design device according to embodiment 1 will be described with reference to Figures 1 to 5. As shown in Figure 1, the station location design device according to embodiment 1 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 (arrangement) of buildings, the heights of buildings, the widths of roads, and the positions of open spaces. 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, it may also be three-dimensional map data representing a three-dimensional map.

[0011] The area setting unit 2 sets an area where service is provided by radio waves transmitted by the 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 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. 2. The area data is obtained by using the base station candidate points A １ ~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 a base station candidate point A １ ~A Ｍ A base station candidate area 30 in which a base station can be deployed and an area 40 in which a cover area in which communication between the base station and mobile stations is to be established are set in a setting region 100. The base station candidate area 30 is indicated by a dashed line in FIG.

[0013] The area 40 where a desired coverage area is to be constructed is indicated by a dashed line in Fig. 2, and is an area where the communication power between the base station and the mobile station exceeds the power required by the communication system, and where a desired coverage area is to be constructed in which communication is possible. The area 40 where a desired coverage area is to be constructed here is an area that is to be covered by the entire wireless system under consideration, and is a base station candidate point A that can be placed in the base station candidate area 30. １ ~A Ｍ In the following description, the area 40 where a coverage area is desired to be established will be simply referred to as the coverage area 40.

[0014] The station location candidate point setting unit 3 sets a base station candidate point A, which is known in advance, in the base station candidate area 30 indicated by the area setting unit 2, as shown in FIG. １ ~A Ｍ The base station candidate point A is placed and set, and the position information indicating the placement position is linked to it. １ ~A Ｍ The base station candidate point A is stored in the base station candidate point storage unit 4. １ ~A Ｍ The arrangement of the base station candidate points A １ ~A Ｍ There are no restrictions on the spacing between base station candidate points. １ ~A Ｍ 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, for example, a radio wave coverage area calculation point B as shown in FIG. 3 within the cover area 40 indicated by the area setting unit 2. １ ~B Ｎ and link the location information to the radio wave coverage area calculation point B. １ ~B Ｎ The radio wave arrival area calculation point B is stored in the radio wave arrival area calculation point storage unit 6. １ ~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, radio wave coverage area calculation point B １is the shortest in straight line distance from the reference point of the base station candidate area 30, and B ２ , B ３ ...B Ｎ are set in this order, and B Ｎ is set as the farthest point in a straight line from the reference point of the base station candidate area 30. The reference point of the base station candidate area 30, which is the reference for the straight line distance, is the base station candidate point A １ ~A Ｍ or the base station candidate point A located at the position farthest from the edge of the coverage area 40. １ ~A Ｍ This is the placement point of the radio wave coverage area calculation point B. １ ~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 point B stored in the radio wave arrival area calculation point storage unit 6. １ ~B 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 point B １ ~B Ｎ is set as a transmission point, and the base station candidate point A stored in the base station candidate point storage unit 4 is set as a transmission point. １ ~A Ｍ A radio wave propagation analysis was carried out with the receiving point at ｎ -A ｍ ) is calculated.

[0018] Generally known ray tracing is used to calculate the propagation loss in the propagation loss calculation unit 7. Note that a generally known propagation loss estimation formula may be used instead of ray tracing, 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 calculates the radio wave coverage area calculation point B that is closest in straight line distance from the reference point of the base station candidate area 30. １ and base station candidate point A １ The radio wave propagation analysis was performed to calculate the propagation loss (B １ -A １ The propagation loss (B １-A １ ) is received by the base station selection unit 8.

[0020] Next, the propagation loss calculation unit 7 calculates the radio wave coverage area at the radio wave coverage area calculation point B. １ and base station candidate point A ２ The radio wave propagation analysis was performed to calculate the propagation loss (B １ -A2), and then calculate the radio wave coverage area at point B. １ The radio wave propagation analysis is performed using the base station candidate point A stored in the base station candidate point storage unit 4 as the transmitting point. １ ~A Ｍ The propagation loss (B １ -A ｍ The propagation loss calculation unit 7 calculates the propagation loss (B １ -A ｍ ) are sequentially received by the base station selection unit 8.

[0021] Thereafter, the propagation loss calculation unit 7 calculates the radio wave coverage area at the radio wave coverage area calculation point B. ２ The radio wave propagation analysis is performed using the remaining base station candidate points A stored in the base station candidate point storage unit 4 as the transmitting points. １ ~A Ｍ and then calculate the radio wave coverage area at point B. ３ From radio wave coverage area calculation point B Ｎ Similarly, radio wave propagation analysis is performed sequentially up to ｎ -A ｍ ) is required.

[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, base station candidate point A １ ~A Ｍ In this case, the base station candidate point A is deleted from the base station candidate point storage unit 4 by the base station selection unit 8. １ ~A Ｍ Therefore, the radio wave coverage area calculation point B １ ~B Ｎ Base station candidate point A to be analyzed for radio wave propagation １ ~A Ｍ The number of base station candidate points A １ ~A Ｍ The number 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 a propagation loss equal to or greater than the threshold are deleted from the base station candidate point storage unit 4. ｎ -A ｍ ) is a base station candidate point A where the propagation loss is greater than or equal to 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 base station candidate points that are not deleted from base station candidate point storage unit 4 by base station selection unit 8, radio wave propagation analysis continues to be performed by propagation loss calculation unit 7. When there are no more base station candidate points stored in base station candidate point storage unit 4 as a result of deleting base station candidate points with propagation loss equal to or greater than the threshold from base station candidate point storage unit 4, base station selection unit 8 determines the last base station candidate point to be deleted from 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 are eliminated are regarded as the selection results. The station location determination unit 9 determines the base station candidate points selected by the base station selection unit 8 as the station locations where the base stations are to be located. The determined station locations are output to an output unit (not shown) as station location information.

[0026] In other words, the propagation loss calculation unit 7 calculates the radio wave coverage area calculation point B that is closest in straight line distance from the reference point of the base station candidate area 30. １ All base station candidate points A set within the base station candidate area 30 are used as transmission points. １ ~A Ｍ A radio wave propagation analysis was carried out with each receiving point to calculate the propagation loss (B １ -A ｍ ) and calculate the remaining radio wave coverage area B ２ ~B ＮOn the other hand, the radio wave coverage area calculation point B is selected in order of the closest straight-line distance from the reference point of the base station candidate area 30. ２ ~B Ｎ is used as a transmitting point, and the remaining base station candidate points excluding the base station candidate points deleted by the base station selection unit 8 are used as receiving points to perform radio wave propagation analysis, thereby obtaining propagation loss.

[0027] Therefore, the propagation loss calculation unit 7 calculates the radio wave coverage area calculation point B that is closest in straight line distance from the reference point of the base station candidate area 30. １ For base station candidate point A １ ~A Ｍ Since the propagation loss for each of the radio wave coverage areas is calculated, there is no risk of the optimum station location candidate being eliminated. ２ ~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 the propagation loss calculation unit 7 is reduced.

[0028] Next, the processing procedure for station placement design by the station placement design device according to the first embodiment will be described with reference to Fig. 4. As an initial setting, the region setting unit 2 sets a setting region 100 from the map information stored in the map information storage unit 1, and the station placement candidate point setting unit 3 sets base station candidate points A and B in the base station candidate area 30 in the setting region 100 set by the region setting unit 2. １ ~A Ｍ and base station candidate point A １ ~A Ｍ The base station candidate point storage unit 4 stores the base station candidate point B in the radio wave arrival area calculation point setting unit 5, and the radio wave arrival area calculation point B is set within the cover area 40 in the setting area 100 set by the area setting unit 2. １ ~B Ｎ Set the radio wave coverage area calculation point B １ ~B Ｎ are 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 the radio wave coverage area calculation point B. ｎ The radio wave coverage area calculation point B is the closest in straight line distance from the reference point of the base station candidate area 30. １and the radio wave arrival area calculation point B stored in the radio wave arrival area calculation point storage unit 6. １ ~B Ｎ Among them, radio wave coverage area calculation point B １ In step ST2, the propagation loss calculation unit 7 reads out the base station candidate point A ｍ Base station candidate point A １ and the base station candidate point A is stored in the base station candidate point storage unit 4. １ ~A Ｍ Base station candidate point A １ and proceeds to step ST3.

[0030] In step ST3, the propagation loss calculation unit 7 calculates the radio wave coverage area at the radio wave coverage area calculation point B. １ is the transmitting point and base station candidate point A １ A radio wave propagation analysis was carried out with the receiving point at B1-A １ ) and proceeds to step ST4. In step ST4, the base station selection unit 8 calculates the propagation loss (B1-A １ ) is compared with a threshold value, and the propagation loss (B1-A １ ) is equal to or greater than the threshold, the base station candidate point A １ In other words, the base station candidate points A stored in the base station candidate point storage unit 4 are excluded. １ ~A Ｍ From base station candidate point A １ Delete.

[0031] In step ST5, if m indicating the 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 now 1, the process proceeds to step ST6, and the propagation loss calculation unit 7 sets m to m+1, that is, 2, to determine the base station candidate point A. ２ is the next candidate for evaluation. ２ When the next evaluation candidate is determined, the process proceeds to step ST3, step ST4, and step ST5, and the propagation loss calculation unit 7 calculates the radio wave coverage area calculation point B １ and base station candidate point A ２ Propagation loss with ２ ) is calculated, and the base station selection unit 8 selects the base station candidate point A ２The process from step ST3 to step ST5 is repeated until m becomes M, and the radio wave coverage area calculation point B １ All base station candidate points A １ ~A Ｍ When the evaluation is completed, the process proceeds to step ST7.

[0032] Radio wave coverage area calculation point B １ For all base station candidate points A １ ~A Ｍ Step ST3 for processing each of the first radio wave coverage area calculation point B １ and a plurality of base station candidate points A that can be arranged in the base station candidate area 30. １ ~A Ｍ Radio wave propagation analysis is carried out for each of the base station candidate points A. １ ~A Ｍ In the first radio wave propagation analysis step, the propagation loss for each of the base station candidate points A is calculated. １ ~A Ｍ Since radio wave propagation analysis is performed and propagation loss is obtained, base station candidate point A １ ~A Ｍ Therefore, there is no risk that the optimum station position candidate will be removed from the list.

[0033] Radio wave coverage area calculation point B １ For all base station candidate points A １ ~A Ｍ Step ST4, which processes the propagation loss resulting from the radio wave propagation analysis for each of the base stations, is a first station 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 some base station candidate points remain, 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, 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, i.e., 2, and the process returns to step ST2, and the second radio wave coverage area calculation point B ２ Step ST3 → Step ST4 → Step ST5 → Step ST6 → Step ST3 → ... Step ST5 is performed for the second radio wave coverage area calculation point B ２ The remaining base station candidate point A １ ~A Ｍ The evaluation is repeated until the end of each step, and the process proceeds to step ST7, step ST8, and step ST9. In step ST9, n is set to n+1, and the third radio wave coverage area calculation point B ３ The second radio wave coverage area calculation point B ２ The same processing is performed for

[0036] Radio wave coverage area calculation point B １ ~B Ｎ In step ST4 for each of the base station candidate points, the base station candidate points that are excluded because the propagation loss is equal to or greater than the threshold are excluded from the station placement candidates. ２ ~B Ｎ In step ST6 for each, the previous radio wave coverage area calculation point B １ ~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. ２ ~B Ｎ In step ST3 for each, the previous radio wave coverage area calculation point B １ ~B Ｎ－１The base station candidate points excluded by the base station selector 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 B ２ ~B Ｎ Step ST3 is performed to sequentially process each of the remaining base station candidate points excluding the base station candidate points excluded in step ST4. ２ ~B 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 a propagation loss for each of the remaining base station candidate points.

[0038] Second and subsequent radio wave coverage area calculation points B ２ ~B Ｎ Step ST4 sequentially processes the propagation loss, which is the result of radio wave propagation analysis with each of the remaining base station candidate points, for each of the remaining base station candidate points, and is a second or subsequent station selection step that sequentially compares the propagation losses sequentially obtained in the second and 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. Because base station candidate points whose propagation loss is equal to or greater than the threshold are excluded in the first and second or subsequent station selection steps, radio wave propagation analysis is not performed for the excluded base station candidate points in the second or subsequent radio wave propagation analysis step, and radio wave propagation analysis is performed for 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 all base station candidate points are deleted as the selection result, and the station location determination unit 9 determines the base station candidate point selected 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 the output unit as station location information.

[0040] In step ST7, for example, the Nth radio wave coverage area calculation point B Ｎ, and the result is that all base station candidate points have been deleted. If it is determined that there are no remaining base station candidate points, 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 Nth radio wave coverage area calculation point B, 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. 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] On the other hand, the N-1th radio wave coverage area calculation point B Ｎ－１ In the process for Ｎ－１ This means that communication with the N-1th radio wave coverage area calculation point B is possible. Ｎ－１ A coverage area can be constructed using the remaining base station candidate points up to the range of 0. These remaining base station candidate points can construct a coverage area of ​​the maximum range in area 40 where a coverage area is to be constructed. Step ST10 is a station placement selection result step in which the base station candidate points that remain undeleted 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 non-volatile 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 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 stored in the ROM 10C and are components that represent functions executed by the CPU 10A based on programs 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; and a second and subsequent radio wave coverage area calculation procedure for sequentially performing radio wave propagation analysis for each of the 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. 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 subjected to radio wave propagation analysis 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 taken 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 B that is closest in straight line distance from the reference point of the base station candidate area 30. １ and a plurality of base station candidate points A stored in the base station candidate point storage unit 4. １ ~A Ｍ The radio wave propagation analysis is sequentially performed for each of the remaining radio wave arrival area calculation points B stored in the radio wave arrival area calculation point storage unit 6. ２ ~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. １ ~A Ｍ For all of the above, the radio wave coverage area calculation point B is the closest in straight line distance from the reference point of the base station candidate area 30. １Since the propagation loss is calculated for each base station candidate point, there is no risk of eliminating the optimum base station location candidate, and furthermore, base station candidate points with propagation loss equal to or greater than a 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 coverage area is to be constructed is located in one direction, and a radio wave coverage area calculation point B １ ~B Ｎ However, if the area 40 exists in multiple directions and the radio wave coverage area calculation point B １ ~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 point B is set up in multiple directions or in parallel. １ ~B Ｎ For each of them, the radio wave coverage area calculation point B set in one direction １ ~B Ｎ There are multiple base station candidate points A １ ~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 base station candidate point 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. A station location design device according to embodiment 2 will be described with reference to Figure 6. The station location design device according to embodiment 2 selects a station from a plurality of base station candidate points by taking into account the directivity or installation direction of the base station antenna (hereinafter abbreviated as antenna) in addition to the placement position in the base station candidate area 30. That is, the station location design device according to embodiment 2 treats different base station candidate points as different base station candidate points if the placement position in the base station candidate area 30 is the same but the antenna directivity or antenna direction is 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 of embodiment 1, and therefore will not be described here.

[0053] The station location candidate point setting unit 3a sets a base station candidate point A, which is known in advance, in the base station candidate area 30 indicated by the area setting unit 2. １ ~A Ｍ and the base station candidate point A １ ~A Ｍ At least one of the directivity or direction of the antenna that can be placed at each of the base stations (hereinafter referred to as the propagation characteristics of the antenna) is set, and the base station candidate point A is linked with information indicating the propagation characteristics of the antenna in addition to the position information indicating the placement position. １ ~A Ｍ The base station candidate point setting unit 3a stores information indicating the above in the base station candidate point storage unit 4a. When the antenna propagation characteristics are different even if the arrangement position is the same, the base station candidate point setting unit 3a sets the base station candidate point as a different base station candidate point.

[0054] The propagation loss calculation unit 7a calculates the propagation loss of the radio wave arrival area calculation point B stored in the radio wave arrival area calculation point storage unit 6. １ ~B 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 point B １ ~B Ｎ is set as a transmission point, and the base station candidate point A stored in the base station candidate point storage unit 4a is set as a transmission point. １ ~A Ｍ A radio wave propagation analysis was carried out with the receiving point at ｎ -Aｍ The propagation loss calculation unit 7a calculates the propagation loss of the base station candidate points A and B, which are different in antenna propagation characteristics even if they are located at the same position. １ ~A Ｍ The propagation characteristics of the antenna are added to the placement position, and 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 with different antenna propagation characteristics are treated as separate base station candidate points even if they have the same placement location. The station location design device according to the second embodiment has the same effects as the station location design device according to the first embodiment, and can also determine the station location where a base station is to be placed by taking into account the antenna propagation characteristics.

[0057] Embodiment 3 A station location design device according to embodiment 3 will be described with reference to Fig. 7. The station location design device according to embodiment 3 receives line-of-sight environment information and calculates second and subsequent radio wave coverage areas B ２ ~B Ｎ The 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 a base station candidate point, or in the third embodiment, a reference point of the base station candidate area 30, are estimated to reach a radio wave coverage area calculation point without being blocked by buildings or the like. In a line-of-sight environment, the propagation loss tends to be similar to that in free space. Therefore, according to the theoretical value of propagation loss, it is possible to predict to some extent the point where the propagation loss will exceed a threshold, and radio wave propagation analysis is omitted 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.

[0059] The station location design device according to the third embodiment performs radio wave propagation analysis on the remaining base station candidate points for the radio wave coverage area calculation point immediately after a set number based on 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 all of the remaining base station candidate points are 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 by one before that until a base station candidate point where the propagation loss is less than the threshold appears. The station location design device according to the third embodiment selects a base station candidate point where the propagation loss is less than the threshold as the location where the base station is to be located.

[0060] As shown in Fig. 7, the station location design device according to embodiment 3 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. Note that 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 propagation loss of the radio wave arrival area calculation point B stored in the radio wave arrival area calculation point storage unit 6. １ and the second and subsequent radio wave coverage area calculation points B until the visibility environment information indicates a visibility environment. ２ ~B ｎ１ The base station candidate points are read out in order of closest straight-line distance from the reference point of the base station candidate area 30, and a radio wave propagation analysis is performed 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, the second radio wave coverage area calculation point B ２ When the line-of-sight environment is indicated for the base station candidate area 30, the propagation loss calculation unit 7b calculates the first radio wave coverage area calculation point B, which is closest in straight line distance from the reference point of the base station candidate area 30. １ is used as a transmitting point, and all base station candidate points A stored in the base station candidate point storage unit 4 are １ ~A 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 calculates the second radio wave coverage area B, which indicates the line-of-sight environment. ２The 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 is omitted. In a line-of-sight environment, the propagation loss tends to be close to the propagation loss in free space, and the propagation loss for each base station candidate point at the radio wave coverage area calculation point within the line-of-sight environment can be estimated based on the straight-line distance between the radio wave coverage area calculation point and the base station candidate point, and by indicating that the line-of-sight environment information is not in a line-of-sight environment, it is possible to predict the radio wave coverage area calculation point where the propagation loss will exceed the threshold.

[0065] The propagation loss calculation unit 7b resumes the radio wave propagation analysis, setting as the transmitting point the radio wave arrival area calculation point where the propagation loss is predicted to exceed the threshold value, and setting as the receiving point each of the remaining base station candidate points stored in the base station candidate point storage unit 4, 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 arrival area calculation points in the direction away from the radio wave arrival area calculation point where the propagation loss is predicted to exceed the threshold value, 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 selector 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. ２ The second and subsequent radio wave coverage calculation points B ２ ~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 transmitting point and each of the remaining base station candidate points stored in the base station candidate point storage unit 4 as the receiving point, and calculates the propagation loss for each. As a result, there are cases where, due to the influence of a multipath environment, etc., the propagation losses for all of the remaining base station candidate points are equal to or greater than the threshold.

[0068] In this case, the propagation loss calculation unit 7b reads out from the radio wave arrival area calculation point storage unit 6 a radio wave arrival 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 arrival area calculation point where the propagation loss is predicted to exceed the threshold, and calculates a second radio wave arrival area calculation point B that indicates a line-of-sight environment. ２ A radio wave propagation analysis is performed 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 the propagation loss analysis for the base station candidate points in step 1.

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

[0070] The station location design device of embodiment 3 has the same effects as the station location design device of 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 7 b 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 7 b 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 selector 8 a selects the base station candidate point where the propagation loss obtained first by the propagation loss calculation unit 7 b is less than the threshold, and therefore the base station candidate point where the largest coverage area is obtained can be the selection result.

[0072] 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 are 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 used.

[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.

[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.

[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 a cover area is to be constructed, A １ ~A Ｍ Base station candidate point, B １ ~B Ｎ Radio wave coverage area calculation point.

Claims

1. A base station placement design device comprising: 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 area based on map information; a radio wave reach area calculation point storage unit that stores a plurality of radio wave reach area calculation points set in an area where it is desired to construct a coverage area in the set area; a propagation loss calculation unit that sequentially performs radio wave propagation analysis between the radio wave reach area calculation point stored in the radio wave reach area calculation point storage unit and 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 reach area calculation points stored in the radio wave reach 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 compares the propagation losses sequentially received by radio wave propagation analysis by the propagation loss calculation unit with a threshold value, deletes base station candidate points whose propagation losses are equal to or greater than the threshold value from the base station candidate point storage unit, and selects, as a selection result, the base station candidate point immediately before all the base station candidate points stored in the base station candidate point storage unit are deleted.

2. The base station placement design device according to claim 1, wherein the area where it is desired to construct a coverage area in the set area exists in one direction, and the plurality of radio wave reach area calculation points stored in the radio wave reach area calculation point storage unit are radio wave reach area calculation points set in one direction.

3. The base station placement design device according to claim 1, wherein the area where it is desired to construct a coverage area in the set area exists in a plurality of directions, and the plurality of radio wave reach area calculation points stored in the radio wave reach area calculation point storage unit are radio wave reach area calculation points set in a plurality of directions.

4. The base station placement design device according to any one of claims 1 to 3, wherein the base station candidate points stored in the base station candidate point storage unit have the directivity of the antenna or the installation direction of the antenna associated with the arrangement position in the base station candidate area, and different base station candidate points are considered when the directivity of the antenna or the direction of the antenna is different even if the arrangement positions are the same.

5. The base station placement design device according to any one of claims 1 to 3, wherein when the propagation loss calculation unit receives line-of-sight environment information with the line-of-sight environment, the propagation loss calculation unit omits performing radio wave propagation analysis on the remaining base station candidate points with respect to the radio wave reach area calculation point immediately before the radio wave reach area calculation point where the propagation loss is predicted to exceed the threshold value.

6. The propagation loss calculation unit performs radio wave propagation analysis on the remaining base station candidate points with respect to the radio wave arrival region calculation points where the propagation loss is predicted to exceed the threshold. When all the propagation losses at the remaining base station candidate points are equal to or greater than the threshold, the radio wave propagation analysis is sequentially performed on the remaining base station candidate points with respect to the radio wave arrival region calculation points immediately before the radio wave arrival region calculation points where the propagation loss is predicted to exceed the threshold, one by one, until a base station candidate point with a propagation loss less than the threshold appears. The station placement design device according to claim 5.

7. A station placement design method for selecting the placement of a base station by a station placement design device including a propagation loss calculation unit and a base station selection unit, wherein: the propagation loss calculation unit sequentially performs radio wave propagation analysis between the first radio wave arrival region calculation point with the shortest straight-line distance from the reference point of the base station candidate area and each of a plurality of base station candidate points that can be arranged in the base station candidate area, to obtain the propagation loss for each of the plurality of base station candidate points, in a first radio wave propagation analysis step; 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 with a propagation loss equal to or greater than the threshold, in a first station placement selection step; the propagation loss calculation unit sequentially performs radio wave propagation analysis between each of the second and subsequent radio wave arrival region calculation points and each of the remaining base station candidate points excluding the base station candidate points excluded by the station placement selection step, to obtain the propagation loss for each of the base station candidate points subjected to the radio wave propagation analysis, in second and subsequent radio wave propagation analysis steps; the base station selection unit sequentially compares the propagation losses sequentially obtained in each of the second and subsequent radio wave propagation analysis steps with the threshold, and excludes base station candidate points with a propagation loss equal to or greater than the threshold, in second and subsequent station placement selection steps; the base station selection unit sets, as the station placement selection result, the base station candidate points that remain undelisted immediately before all the base station candidate points are deleted by the base station selection unit, in a station placement selection result step.

8. A station placement design program that causes a computer to execute: a first radio wave propagation analysis procedure that sequentially performs radio wave propagation analysis between a first radio wave arrival area calculation point that is the closest in terms of the straight-line distance from a reference point of a base station candidate area and each of a plurality of base station candidate points that can be arranged in the base station candidate area, and obtains propagation loss for each of the plurality of base station candidate points; a first station placement selection procedure that sequentially compares the propagation loss sequentially obtained in the first radio wave propagation analysis procedure with a threshold value, and excludes base station candidate points whose propagation loss is greater than or equal to the threshold value; a second and subsequent radio wave propagation analysis procedure that sequentially performs radio wave propagation analysis between each of the second and subsequent radio wave arrival area calculation points and each of the remaining base station candidate points excluding the base station candidate points excluded by the station placement selection procedure, and obtains propagation loss for each of the base station candidate points subjected to the radio wave propagation analysis; a second and subsequent station placement selection procedure that sequentially compares the propagation loss sequentially obtained in each of the second and subsequent radio wave propagation analysis procedures with the threshold value, and excludes base station candidate points whose propagation loss is greater than or equal to the threshold value; and a station placement selection result procedure that sets the base station candidate points that remain without being deleted immediately before all base station candidate points are deleted as the station placement selection result.

9. A recording medium storing a program that causes a computer to execute: a first radio wave propagation analysis procedure that sequentially performs radio wave propagation analysis between a first radio wave arrival area calculation point that is the closest in terms of the straight-line distance from a reference point of a base station candidate area and each of a plurality of base station candidate points that can be arranged in the base station candidate area, and obtains propagation loss for each of the plurality of base station candidate points; a first station placement selection procedure that sequentially compares the propagation loss sequentially obtained in the first radio wave propagation analysis procedure with a threshold value, and excludes base station candidate points whose propagation loss is greater than or equal to the threshold value; a second and subsequent radio wave propagation analysis procedure that sequentially performs radio wave propagation analysis between each of the second and subsequent radio wave arrival area calculation points and each of the remaining base station candidate points excluding the base station candidate points excluded by the station placement selection procedure, and obtains propagation loss for each of the base station candidate points subjected to the radio wave propagation analysis; a second and subsequent station placement selection procedure that sequentially compares the propagation loss sequentially obtained in each of the second and subsequent radio wave propagation analysis procedures with the threshold value, and excludes base station candidate points whose propagation loss is greater than or equal to the threshold value; and a station placement selection result procedure that sets the base station candidate points that remain without being deleted immediately before all base station candidate points are deleted as the station placement selection result.

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