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

Abstract

This station placement design device: selects, from a plurality of base station candidates which are candidates for the placement position of a base station, a first base station placement which is a combination of base station candidates in which the base station is to be placed; generates a second base station placement by calculating an evaluation value for the first base station placement on the basis of wireless quality values in the first base station placement at a plurality of points, and if the evaluation value is less than a threshold, changing any one base station candidate constituting the first base station placement to any base station candidate not included in the first base station placement; every time the second base station placement is generated, calculates an evaluation value for the second base station placement on the basis of wireless quality values in the second base station placement at the plurality of points; every time the second base station placement is generated, selects, as an output candidate, the base station placement having the higher evaluation value, among the first base station placement and the second base station placement; and repeats the generation of the second base station placement using, as the first base station placement, the base station placement selected as the output candidate, thereby making it possible to derive a base station placement suitable for the whole area by a smaller calculation amount than in an exhaustive search.

Description

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

[0001] The present invention relates to a station placement design device, a station placement design method, and a program.

[0002] Because there are limits to the range of radio waves from a wireless base station and the number of terminals that a single wireless base station can accommodate, installing too few wireless base stations results in insufficient area coverage and terminal capacity. On the other hand, installing too many wireless base stations increases the cost of the base station equipment itself, as well as installation and operation costs, resulting in inefficiency. Therefore, it is necessary to install a sufficient number of wireless base stations in appropriate locations. Furthermore, because the communication performance and equipment costs obtained differ depending on the wireless communication method, it is important to consider the combination of wireless communication methods when designing wireless stations.

[0003] For example, Non-Patent Document 1 proposes a method for designing wireless stations based on communication quality and cost by combining a plurality of wireless systems.

[0004] Toshiro Nakahira, Daisuke Murayama, Satoshi Takatani, Kenichi Kawamura, Takatsugu Moriyama, "Multi-Radio Area Design Method Based on Communication Capacity and Base Station Cost," IEICE Techniques, IEICE General Conference, B-5-97, Mar. 2022

[0005] In the conventional technology described in Non-Patent Document 1, base stations are selected and placed one by one from base station placement candidates using a greedy method, which does not necessarily result in base station placement that is suitable for the entire area. Therefore, a method that performs an exhaustive search to find the optimal base station placement from the base station placement candidates can be considered, but the amount of calculation increases as the number of base station placement candidates increases.

[0006] The present invention has been made in view of the above points, and has as its object to make it possible to derive a base station arrangement suitable for the entire area with a smaller amount of calculation than a full search.

[0007] In order to solve the above problem, a station location design device includes: a base station location selection unit configured to select a first base station location, which is a combination of base station candidates to be used for arranging a base station, from among a plurality of base station candidates that are candidates for base station locations; a first evaluation unit configured to calculate an evaluation value for the first base station location based on wireless quality values ​​in the first base station location at a plurality of points; a base station location modification unit configured to generate a second base station location by changing any one of the base station candidates constituting the first base station location to any base station candidate not included in the first base station location, if the evaluation value is less than a threshold; a second evaluation unit configured to calculate an evaluation value for the second base station location based on wireless quality values ​​in the second base station location at the plurality of points, each time the second base station location is generated; and an output candidate selection unit configured to select, as an output candidate each time the second base station location is generated, one of the first base station location and the second base station location having the higher evaluation value; and the base station location modification unit repeats generating the second base station location by using the output candidate selected by the output candidate selection unit as the first base station location.

[0008] It is possible to derive an appropriate base station arrangement for the entire area with less computational effort than with a full search.

[0009] Fig. 1 is a diagram illustrating an example of a hardware configuration of a station placement design device 10 according to an embodiment of the present invention. Fig. 2 is a diagram illustrating an example of a functional configuration of the station placement design device 10 according to an embodiment of the present invention. Fig. 3 is a flowchart illustrating an example of a processing procedure executed by the station placement design device 10. Fig. 4 is a diagram illustrating a target achievement level of base station placement. Fig. 5 is a diagram illustrating selection of base station placement of output candidates.

[0010] In this embodiment, a station location design device 10 is disclosed that first determines a base station location tentatively, randomly selects one radio base station (hereinafter simply referred to as a "base station"), and changes it to another base station location candidate. The device compares the degree of target achievement before and after the change, and if there is an improvement, the base station is changed, or if there is no improvement, the base station is not changed. By repeating this process a predetermined number of times, it is possible to derive a base station location that is appropriate for the entire area with less computational effort than a full search.

[0011] An embodiment of the present invention will now be described with reference to the drawings. Fig. 1 is a diagram showing an example of the hardware configuration of a station location design device 10 according to an embodiment of the present invention. The station location design device 10 in Fig. 1 includes a drive device 100, an auxiliary storage device 102, a memory device 103, a processor 104, and an interface device 105, all of which are interconnected via a bus B.

[0012] A program that realizes the processing in the station design device 10 is provided by a recording medium 101 such as a CD-ROM. When the recording medium 101 storing the program is set in the drive device 100, the program is installed from the recording medium 101 to the auxiliary storage device 102 via the drive device 100. However, the program does not necessarily have to be installed from the recording medium 101, but may be downloaded from another computer via a network. The auxiliary storage device 102 stores the installed program as well as necessary files, data, etc.

[0013] When an instruction to start the program is received, the memory device 103 reads and stores the program from the auxiliary storage device 102. The processor 104 is a CPU or a GPU (Graphics Processing Unit), or a CPU and a GPU, and executes functions related to the station design device 10 in accordance with the program stored in the memory device 103. The interface device 105 is used as an interface for connecting to a network.

[0014] 2 is a diagram showing an example of the functional configuration of a station location design device 10 according to an embodiment of the present invention. In FIG. 2, the station location design device 10 includes an initial placement unit 11, a wireless quality calculation unit 12, a base station location selection unit 13, an evaluation unit 14, a base station location modification unit 15, an output candidate selection unit 16, and an output unit 17. Each of these units is implemented by a processor 104 executing one or more programs installed in the station location design device 10. The station location design device 10 also uses a data storage unit 121. The data storage unit 121 can be implemented using, for example, the auxiliary storage device 102 or a storage device connectable to the station location design device 10 via a network.

[0015] The following describes the processing procedure executed by the station placement design device 10. FIG.

[0016] In step S101, the initial placement unit 11 places terminals and base station candidates within an area (hereinafter referred to as the "target area") where the base station is to be placed. Here, the term "terminal" refers to a location where the terminal is located or is expected to be located, and has the meaning of a location where the wireless quality of the base station is evaluated. The term "base station candidate" refers to a location that is a candidate for the placement location of the base station, and multiple base station candidates are set in advance. Information about the geographical range of the target area, the terminals, and the base station candidates are stored in advance in the data storage unit 121.

[0017] Next, the wireless quality calculation unit 12 calculates, for each terminal, an estimated value of the received power from each base station candidate (hereinafter referred to as the "received power value") (S102). The calculation of the received power value can be performed using a known radio wave propagation estimation technique or the like. Parameters required for the calculation (e.g., wireless parameters of the base station, etc.) may be stored in advance in the data storage unit 121.

[0018] Next, the base station placement selection unit 13 assigns 1 to the variable m (S103), which indicates the number of base stations to be placed.

[0019] Next, the base station placement selection unit 13 randomly selects m base station installation numbers from the base station candidates and places the base stations in the selected base station candidates (S104). Therefore, m base stations are placed. The placement pattern of m base stations (combination of base station candidates in which m base stations are placed) is hereinafter referred to as the "base station placement pattern p ｓ "

[0020] Next, the evaluation unit 14 evaluates the base station arrangement p ｓ Based on the received power values ​​at multiple terminals (multiple locations) in ｓ The evaluation value for the goal achievement level s ｓ Evaluate (calculate) the goal achievement level s ｓ The base station placement p ｓ The data is recorded in the memory device 103 or the like in association with the above (S105).

[0021] Fig. 4 is a diagram for explaining the degree of target achievement of base station placement. In the table of Fig. 4, each row corresponds to m base station candidates, and each column corresponds to a terminal (evaluation score). A numerical value in a certain column of a certain row indicates the received power value (dBm) from the base station candidate corresponding to that row for the terminal corresponding to that column. However, "-" indicates that there is no value (radio waves are not received).

[0022] The evaluation unit 14 calculates the maximum value of the received power value for each terminal and compares this maximum value with a target value that is set in advance for that terminal and stored in the data storage unit 121. The evaluation unit 14 determines that a terminal whose maximum value is equal to or greater than the target value has achieved the target, and calculates the ratio of the number of terminals that have achieved the target to the total number of terminals as the degree of target achievement.

[0023] Next, the base station allocation change unit 15 assigns 1 to the variable i (S106). ｓ This is a variable for counting the number of times the base station candidates constituting the RBW are changed.

[0024] Next, the base station allocation modification unit 15 determines whether the variable i is equal to or less than a preset upper limit I (S107). The value of I may be set appropriately. For example, the value of I may be equal to or less than (target processing time) / (required time per process). The required time per process may be determined based on the number of terminals (evaluation points).

[0025] If i is equal to or smaller than the upper limit I (Yes in S107), the base station allocation change unit 15 calculates the target achievement degree s ｓ is a predetermined threshold s ｔ It is determined whether the target achievement level s is equal to or greater than the target achievement level s (S108). ｓ is the threshold s ｔ If the number is equal to or greater than the number (Yes in S108), the output unit 17 outputs the base station arrangement p ｓ is output (S116), and the processing procedure of FIG. 3 ends.

[0026] Goal achievement level s ｓ is the threshold s ｔ If the number of base stations is less than the number of base stations in the area where the target base station is located (No in S108), the base station allocation modification unit 15 excludes one randomly selected deployed base station (hereinafter referred to as the "target base station"), and then randomly selects one base station candidate where no base station is currently installed (excluding the base station candidate where the target base station was located), and newly deploys the base station (S109). ｓ Any one of the base station candidates constituting the base station arrangement p ｓ A new base station arrangement p' is generated by changing the base station candidate to one that is not included in

[0027] Subsequently (each time a base station arrangement p' is generated), the evaluation unit 14 evaluates (calculates) the target achievement level s' for the base station arrangement p' using the same method as in step S105 (S110).

[0028] Next, the output candidate selection unit 16 selects the goal achievement level s ｓ is less than the target achievement level s' (S111). ｓ It is determined whether the degree of goal achievement is higher than that of the previous one.

[0029] Goal achievement level sｓ If the target achievement level s' is equal to or greater than the target achievement level s' (No in S111), the process proceeds to step S113. ｓ is less than the goal achievement level s' (Yes in S111), the output candidate selection unit 16 ｓ Substituting s' into p ｓ In other words, the output candidate selection unit 16 determines whether the goal achievement level s' is greater than the goal achievement level s ｓ If it is higher, base station arrangement p' is selected as an output candidate; otherwise, base station arrangement p is selected as an output candidate.

[0030] FIG. 5 is a diagram for explaining the selection of base station arrangements of output candidates. ｓ The base station arrangement p' is shown as an example. ｓ and base station arrangement p', the one with a higher degree of goal achievement is selected as an output candidate.

[0031] Returning to Fig. 3, in step S113, the base station layout modification unit 15 adds 1 to the variable i. Then, step S107 is repeated. Therefore, the base station layout modification unit 15 adds 1 to the base station layout p selected as an output candidate by the output candidate selection unit 16. ｓ Any one of the base station candidates constituting the base station arrangement p ｓ The base station candidate p' is changed to one that is not included in the base station candidate p', and a new base station arrangement p' is repeatedly generated.

[0032] In this process, if the value of variable i exceeds the upper limit I (No in S107), the base station placement selection unit 13 determines whether the value of variable m is less than the upper limit M of base station placement (S114). If the value of variable m is less than the upper limit M of base station placement (Yes in S114), the base station placement selection unit 13 adds 1 to m (S115) and repeats step S104 and subsequent steps. That is, the base station placement is changed multiple times (I times) until the target achievement degree of all base station placements exceeds the threshold value s ｔ If the number is less than the predetermined number, the number of base station candidates to which the base station is to be allocated is increased, and step S104 and subsequent steps are executed again. In this case, the initial state is a state in which no base station is allocated to any of the base station candidates.

[0033] When the value of the variable m becomes equal to or greater than the upper limit M of the number of base stations (No in S114), the output unit 17 outputs the base station arrangement p ｓ is output (S116), and the processing procedure of FIG. 3 ends.

[0034] As described above, according to this embodiment, it is possible to derive a base station arrangement suitable for the entire area with a smaller amount of calculation than with a full search.

[0035] Although the above description assumes a single wireless system or wireless method, multiple wireless systems or wireless methods may be mixed. In this case, by using indicators such as communication capacity or throughput as the wireless quality value instead of the received power value, it becomes possible to compare different wireless systems or wireless methods.

[0036] In the present embodiment, the evaluation unit 14 is an example of a first evaluation unit and a second evaluation unit.

[0037] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

[0038] REFERENCE SIGNS LIST 10 Station placement design device 11 Initial placement unit 12 Wireless quality calculation unit 13 Base station placement selection unit 14 Evaluation unit 15 Base station placement change unit 16 Output candidate selection unit 17 Output unit 100 Drive device 101 Recording medium 102 Auxiliary storage device 103 Memory device 104 Processor 105 Interface device 121 Data storage unit B Bus

Claims

1. A base station placement selection unit configured to select a first base station placement, which is a combination of base station candidates to be the placement target of a base station, from among a plurality of base station candidates that are candidates for the placement position of the base station; a first evaluation unit configured to calculate an evaluation value for the first base station placement based on radio quality values at a plurality of points in the first base station placement; a base station placement change unit configured to generate a second base station placement by changing any one of the base station candidates constituting the first base station placement to any base station candidate not included in the first base station placement when the evaluation value is less than a threshold; a second evaluation unit configured to calculate an evaluation value for the second base station placement based on radio quality values at the plurality of points in the second base station placement each time the second base station placement is generated; and an output candidate selection unit configured to select, each time the second base station placement is generated, the one with the higher evaluation value between the first base station placement and the second base station placement as an output candidate, wherein the base station placement change unit repeats the generation of the second base station placement with the one selected by the output candidate selection unit as the first base station placement. A station placement design device characterized by the above.

2. The station placement design device according to claim 1, wherein the base station placement selection unit is configured to increase the number of base station candidates to be the placement target of the base station and select the first base station placement when the evaluation values of any of the plurality of repeatedly generated second base station placements are all less than the threshold.

3. A base station placement selection procedure for selecting a first base station placement that is a combination of base station candidates to be the placement target of a base station from among a plurality of base station candidates that are candidates for the placement position of the base station; a first evaluation procedure for calculating an evaluation value for the first base station placement based on radio quality values at a plurality of points in the first base station placement; a base station placement change procedure for generating a second base station placement by changing any one base station candidate constituting the first base station placement to any base station candidate not included in the first base station placement when the evaluation value is less than a threshold value; a second evaluation procedure for calculating an evaluation value for the second base station placement based on radio quality values at the plurality of points in the second base station placement each time the second base station placement is generated; an output candidate selection procedure for selecting, each time the second base station placement is generated, the one with the higher evaluation value among the first base station placement and the second base station placement as an output candidate; a computer executes these procedures; the base station placement change procedure repeats the generation of the second base station placement with the one selected as the output candidate by the output candidate selection procedure as the first base station placement. A station placement design method characterized by this.

4. A base station arrangement selection procedure for selecting a first base station arrangement that is a combination of base station candidates to be the base station to be arranged from among a plurality of base station candidates that are candidates for the arrangement position of the base station; a first evaluation procedure for calculating an evaluation value for the first base station arrangement based on radio quality values at a plurality of points in the first base station arrangement; a base station arrangement change procedure for generating a second base station arrangement by changing any one base station candidate constituting the first base station arrangement to any base station candidate not included in the first base station arrangement when the evaluation value is less than a threshold value; a second evaluation procedure for calculating an evaluation value for the second base station arrangement based on radio quality values at the plurality of points in the second base station arrangement each time the second base station arrangement is generated; an output candidate selection procedure for selecting, each time the second base station arrangement is generated, the one with the higher evaluation value among the first base station arrangement and the second base station arrangement as an output candidate; causing a computer to execute; the base station arrangement change procedure repeats the generation of the second base station arrangement with the one selected as the output candidate by the output candidate selection procedure as the first base station arrangement. A program characterized by this.

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