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

Abstract

This station establishment design device comprises: an area setting unit that sets an area for which to perform station establishment design; a distributed antenna system (DAS) position candidate setting unit that sets a plurality of antenna position candidates that are candidates for installation positions of a DAS; a user equipment (UE) position setting unit that sets a plurality of UE positions at which a UE can be present; a distance calculation unit that calculates distances for all combinations of the antenna position candidates and the UE positions; an angle calculation unit that calculates, for all of the combinations, the azimuth angles of the antenna position candidates as viewed from the UE positions; a propagation path calculation unit that calculates propagation paths for all of the combinations; a determination unit that determines, on the basis of the calculated distances and the calculated propagation paths, whether a UE position can be covered by an antenna position candidate; and a selection unit that, on the basis of the result of the determination, selects the installation positions for the DAS such that an objective function using the angular spread of the calculated azimuth angles is maximized while all the UE positions are covered by at least a prescribed number of antenna position candidates.

Description

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

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

[0002] In communication systems beyond the sixth-generation mobile communication system (6G), the use of high-frequency bands, such as millimeter waves, which can secure wideband bandwidth, is being considered in order to achieve even faster and larger-capacity communications. Since radio wave propagation attenuation due to obstructions is significant in high-frequency bands, measures to combat obstructions are important. One promising solution to this problem is the use of high-frequency band distributed MIMO (Multi-Input, Multi-Output) technology, in which multiple antennas are spatially distributed from a single base station and wireless transmission is performed to mobile terminals from multiple directions (see, for example, Non-Patent Document 1). Furthermore, the distributed antenna arrangement reduces the spatial correlation of the MIMO channel, which is expected to improve communication channel capacity.

[0003] However, distributing a large number of antennas within a wireless service area poses cost challenges, so it is desirable to minimize the number of deployed antennas. One approach to address this challenge is to apply the k-coverage problem, which is widely used in wireless sensor networks, to find a solution. The k-coverage problem is an optimization problem that finds a layout that minimizes the total number of sensors while ensuring that any point within the area is covered by at least k sensors (see, for example, Non-Patent Document 2). The k-coverage problem can be solved by an optimization method such as the Greedy method.

[0004] "White Paper: 5G Advancements and 6G", NTT DOCOMO, 5th Edition, November 2022. B. Mahmoudi et al., "A new hybrid algorithm integrating genetic algorithm with Tabu search to solve imbalanced k-coverage problem in directional sensor networks," IET(The Institution of Engineering and Technology) Communications 2023;17, pp.1243-1254, March 2023.

[0005] However, in the field of wireless sensor networks, approaches to the k-coverage problem are mainly used to ensure redundancy against sensor failures, dead batteries, etc. In other words, this approach is not used for the purpose of distributing sensors. In light of this, if the above approach is directly applied to the problem of distributing antennas in a high-frequency band distributed MIMO system, it is expected that a situation may arise in which multiple distributed antennas are disposed in close proximity to each other, as shown in FIG. 9 .

[0006] The high-frequency band distributed MIMO system demonstrates its true value by spatially distributing multiple distributed antennas, thereby improving robustness against obstructions, as shown in Fig. 10. Therefore, there has been a problem in that it is difficult to directly apply the approach to the k-coverage problem to the distributed antenna placement problem.

[0007] In view of the above circumstances, an object of the present invention is to provide a technique that enables distributed antennas to be distributed and arranged more effectively while suppressing increases in costs.

[0008] One aspect of the present invention is a system including an area setting unit that sets an area for which station placement design is performed, an antenna position candidate setting unit that sets a plurality of antenna position candidates that are candidate installation positions for distributed antennas in the area, a terminal position setting unit that sets a plurality of terminal positions that are positions where terminal devices can be present in the area, a distance calculation unit that calculates distances between the antenna position candidates and the terminal positions for all combinations of the plurality of antenna position candidates and the plurality of terminal positions, an angle calculation unit that calculates azimuth angles of the antenna position candidates as seen from the terminal positions for all combinations of the plurality of antenna position candidates and the plurality of terminal positions, and The station location design device includes: a propagation path calculation unit that calculates a propagation path for each of all combinations of the antenna position candidate and a plurality of the terminal positions; a determination unit that determines whether the antenna position candidate is a terminal position that can be covered, based on the distance calculated by the distance calculation unit and the propagation path calculated by the propagation path calculation unit; and a selection unit that selects installation positions of the distributed antennas, based on a result of the determination by the determination unit, so that an objective function using an angle spread of the azimuth angle calculated by the angle calculation unit is maximized while all the terminal positions are covered by a predetermined number or more of the antenna position candidates.

[0009] Another aspect of the present invention is a station placement design method executed by a computer, the method including: an area setting step of setting an area for station placement design; an antenna position candidate setting step of setting a plurality of antenna position candidates which are candidate installation positions of distributed antennas in the area; a terminal position setting step of setting a plurality of terminal positions which are positions where terminal devices may be present in the area; a distance calculation step of calculating, for all combinations of the plurality of antenna position candidates and the plurality of terminal positions, distances between the antenna position candidates and the terminal positions; and an angle calculation step of calculating, for all combinations of the plurality of antenna position candidates and the plurality of terminal positions, azimuth angles of the antenna position candidates as seen from the terminal positions. a propagation path calculation step of calculating a propagation path for each of all combinations of the plurality of antenna position candidates and the plurality of terminal positions; a determination step of determining whether the antenna position candidates are terminal positions that can be covered based on the distances calculated in the distance calculation step and the propagation paths calculated in the propagation path calculation step; and a selection step of selecting installation positions of the distributed antennas based on the determination result in the determination step so that an objective function using an angle spread of the azimuth angles calculated in the angle calculation step is maximized while all of the terminal positions are covered by a predetermined number or more of the antenna position candidates.

[0010] Another aspect of the present invention is a method for designing a base station by using a computer, the method including: an area setting step for setting an area for which a station placement design is to be performed; an antenna position candidate setting step for setting a plurality of antenna position candidates which are candidate installation positions for a distributed antenna in the area; a terminal position setting step for setting a plurality of terminal positions which are positions where a terminal device may be present in the area; a distance calculation step for calculating a distance between each of the antenna position candidates and each of the terminal positions for all combinations of the plurality of antenna position candidates and each of the terminal positions; an angle calculation step for calculating an azimuth angle of each of the antenna position candidates as seen from the terminal position for all combinations of the plurality of antenna position candidates and each of the terminal positions; a propagation path calculation step of calculating a propagation path for each of all combinations of antenna position candidates and a plurality of terminal positions; a determination step of determining whether the antenna position candidates are coverable terminal positions based on the distances calculated in the distance calculation step and the propagation paths calculated in the propagation path calculation step; and a selection step of selecting installation positions of the distributed antennas based on the determination result in the determination step so that an objective function using an angle spread of the azimuth angles calculated in the angle calculation step is maximized while all the terminal positions are covered by a predetermined number or more of the antenna position candidates.

[0011] According to the present invention, it is possible to provide a technique that enables distributed antennas to be distributed and arranged more effectively while suppressing increases in cost.

[0012] 1 is a block diagram showing a functional configuration of a station placement design device 1 according to an embodiment of the present invention. Ｎ , d Ｎ1 is a diagram illustrating an example of a DAS coverage possibility list generated by a DAS-UE angle calculation unit 15 in an embodiment of the present invention. FIG. 2 is a diagram illustrating an example of a DAS coverage possibility list generated by a coverable UE determination unit 17 of each DAS in an embodiment of the present invention. FIG. 3 is a diagram illustrating a situation in which a plurality of distributed antennas are arranged close to each other. FIG. 4 is a diagram illustrating a situation in which a plurality of distributed antennas are arranged spatially distributed.

[0013] Hereinafter, a station placement design device, a station placement design method, and a station placement design program according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the embodiment described below is an example, and the embodiments to which the present invention can be applied are not limited to these.

[0014] [Configuration of Station Location Design Device] The configuration of the station location design device 1 in this embodiment will be described below. Fig. 1 is a block diagram showing the functional configuration of the station location design device 1 in one embodiment of the present invention. As shown in Fig. 1, the station location design device 1 includes an area setting unit 11, a distributed antenna (DAS) position candidate setting unit 12, a user equipment (UE) position setting unit 13, a DAS-UE distance calculation unit 14, a DAS-UE angle calculation unit 15, a DAS-UE propagation path calculation unit 16, a coverable UE determination unit 17 for each DAS, and a DAS position selection unit 18.

[0015] The area setting unit 11 sets an area to be targeted for station placement design using data including the positions and heights of buildings, such as 3D (dimensional) map information, etc. The area setting unit 11 outputs information indicating the set area to the distributed antenna (DAS) position candidate setting unit 12 and the user equipment (UE) position setting unit 13.

[0016] The distributed antenna (DAS) position candidate setting unit 12 sets candidates for DAS installation positions (hereinafter also referred to as "DAS position candidates") within the area set by the area setting unit 11. Possible DAS position candidates include, for example, building walls and utility poles.

[0017] The user terminal (UE) position setting unit 13 sets a position where a UE may be present (hereinafter also referred to as a "UE position") within the area set by the area setting unit 11. Specifically, the user terminal (UE) position setting unit 13 may divide the area where a UE may be present into a grid, and regard each cell of the grid as a UE position.

[0018] The DAS-UE distance calculation unit 14 calculates the distance between the DAS position candidate set by the distributed antenna (DAS) position candidate setting unit 12 and the UE position set by the user terminal (UE) position setting unit 13 for all combination patterns.

[0019] The DAS-UE angle calculation unit 15 calculates the angle between the DAS position candidate set by the distributed antenna (DAS) position candidate setting unit 12 and the UE position set by the user terminal (UE) position setting unit 13 for all combination patterns of the two. The angle between the two here refers to the azimuth angle to the DAS position candidate as seen from the UE position.

[0020] The DAS-UE propagation path calculation unit 16 calculates propagation paths for all combination patterns of DAS position candidates set by the distributed antenna (DAS) position candidate setting unit 12 and UE positions set by the user terminal (UE) position setting unit 13. The propagation paths calculated here may be propagation paths based simply on the presence or absence of line of sight between the DAS position candidate and the UE position, or may be propagation paths based on direct waves, reflected waves, diffracted waves, and scattered waves calculated by performing ray tracing or the like.

[0021] The coverable UE determination unit 17 of each DAS determines the UE positions that can be covered by each DAS position candidate based on the DAS-UE distance calculated by the DAS-UE distance calculation unit 14 and the DAS-UE propagation path calculated by the DAS-UE propagation path calculation unit 16.

[0022] The DAS position selection unit 18 selects an effective DAS position from among the DAS position candidates based on the DAS-UE distance calculated by the DAS-UE distance calculation unit 14, the azimuth angle to the DAS position candidate as seen from the UE position calculated by the DAS-UE angle calculation unit 15, and the DAS-UE propagation path calculated by the DAS-UE propagation path calculation unit 16. The method for selecting this DAS position will be described below.

[0023] Specifically, when selecting a DAS position using various optimization methods, the DAS position selection unit 18 selects an angle φ of the DAS position candidate as viewed from the UE position. ｍ Angular spread (AS) σ(φ ｍ ) and the distance vector d between the UE and the DAS ｍ Function X(d ｍ The objective function is to maximize XAS, which is the product of φ ｍ is a vector of angles between the m-th UE position and N DAS position candidates that cover the m-th UE position. ｍ is a vector of distances between the mth UE position and N DASs that cover the mth UE position. Coverage is determined based on the calculation results of the DAS-UE distance and the DAS-UE propagation path.

[0024] FIG. 2 shows the elements φ of each vector. Ｎ , d Ｎ The angle spread (AS) σ(φ ｍ ) can be calculated by the following formula (1).

[0025]

[0026] From this equation (1), it can be seen that if only the angular spread (AS) is used, the DAS may be overestimated even when the UE-DAS distance is long. For example, in equation (1), d ｍ=[100,100,100],φ ｍ = [0, π / 2, π], and d ｍ =[500,100,100],φ ｍ = [0, π / 2, π] will be evaluated equally. ｍ is input, AS is multiplied by a function X that takes a small value, and XAS is used as the objective function.

[0027] For example, the function X may be a function based on the probability of shadowing, which increases with the distance between the transmitter and receiver. The DAS position selection unit 18 introduces the calculated XAS into an objective function and selects an effective DAS position using various optimization techniques.

[0028] 3 and 4 are flowcharts showing an example of a station placement design process by the station placement design device 1 in one embodiment of the present invention. The station placement design process shown in Fig. 3 and 4 is a process based on an approach to the k-coverage problem. The k-coverage problem is an optimization problem that finds a placement that minimizes the total number of sensors while ensuring that any point in an area (the UE position in this embodiment) is covered by at least k sensors (DAS position candidates in this embodiment).

[0029] The area setting unit 11 receives input of data indicating a map of an area where stations are to be placed (step S01). The input map data is, for example, data including the positions and heights of buildings, such as 3D map information. The area setting unit 11 uses the input data to set the area to be targeted for station placement design.

[0030] Next, the distributed antenna (DAS) position candidate setting unit 12 sets N DAS position candidates within the area set by the area setting unit 11 (step S02). Next, the user equipment (UE) position setting unit 13 sets M UE positions within the area set by the area setting unit 11 (step S03).

[0031] Next, the DAS-UE propagation path calculation unit 16 determines whether there is line of sight for all combination patterns of the DAS position candidates set by the distributed antenna (DAS) position candidate setting unit 12 and the UE positions set by the user equipment (UE) position setting unit 13. The DAS-UE propagation path calculation unit 16 generates a line of sight list based on the determination result (step S04). Figure 5 is a diagram showing an example of the line of sight list generated by the DAS-UE propagation path calculation unit 16 in one embodiment of the present invention.

[0032] Next, the DAS-UE distance calculation unit 14 calculates the distance between the DAS position candidates set by the distributed antenna (DAS) position candidate setting unit 12 and the UE positions set by the user terminal (UE) position setting unit 13 for all combination patterns of the DAS position candidates set by the distributed antenna (DAS) position candidate setting unit 12 and the UE positions set by the user terminal (UE) position setting unit 13. Furthermore, the DAS-UE angle calculation unit 15 calculates the angle between the DAS position candidates set by the distributed antenna (DAS) position candidate setting unit 12 and the UE positions set by the user terminal (UE) position setting unit 13 for all combination patterns of the DAS position candidates set by the distributed antenna (DAS) position candidate setting unit 12 and the UE positions set by the user terminal (UE) position setting unit 13. As described above, the angle between the two here refers to the azimuth angle to the DAS position candidate as seen from the UE position.

[0033] The DAS-UE distance calculation unit 14 generates a DAS-UE distance list based on the calculation results. Fig. 6 is a diagram showing an example of the DAS-UE distance list generated by the DAS-UE distance calculation unit 14 in one embodiment of the present invention. In addition, the DAS-UE angle calculation unit 15 generates a DAS-UE angle list based on the calculation results (step S05). Fig. 7 is a diagram showing an example of the DAS-UE angle list generated by the DAS-UE angle calculation unit 15 in one embodiment of the present invention.

[0034] Next, the coverable UE determination unit 17 of each DAS determines whether a combination pattern is determined to have line of sight (true) in the line of sight presence / absence list (FIG. 4) generated by the DAS-UE propagation path calculation unit 16, and the distance value in the DAS-UE distance list (FIG. 5) generated by the DAS-UE distance calculation unit 14 is a predetermined value (d ｍａｘ) or less. The coverable UE determination unit 17 of each DAS determines that the UE position of the identified combination pattern is a UE position that can be covered by the DAS. The coverable UE determination unit 17 of each DAS generates a DAS coverability / non-coverability list based on the determination result (step S06). Figure 8 is a diagram showing an example of the DAS coverability / non-coverability list generated by the coverable UE determination unit 17 of each DAS in one embodiment of the present invention.

[0035] Next, the DAS position selection unit 18 selects, as the first DAS position candidate (antenna position), the DAS position candidate that covers the most UE positions, based on the DAS coverage availability list generated by the coverable UE determination unit 17 of each DAS. The DAS position selection unit 18 adds the selected DAS position candidate (antenna position) to a selected DAS list (not shown) (step S07).

[0036] The selection of the second and subsequent DAS positions is performed according to the processing from step S08 onward. The DAS position selection unit 18 determines whether there is a UE position that has been covered less than k times (the number of antennas that cover it) (step S08). If it is determined that there is no UE position that has been covered less than k times (step S08: No), the station placement design processing shown in Figures 3 and 4 ends.

[0037] On the other hand, if it is determined that there is a UE location that has been covered less than k times (step S08: Yes), the top X DAS location candidates that have the most UE locations that can be covered and have been covered less than k times are obtained from the unselected DAS location candidates (step S09). Note that the upper limit of X may be infinite, but the smaller the number of X, the faster this process operates.

[0038] Next, the DAS position selection unit 18 determines whether x is less than or equal to X (step S10). x is a number assigned to the acquired X DAS position candidates. If x is less than or equal to X (step S10, Yes), the DAS position selection unit 18 counts the number of UE positions covered by DAS position candidate x that are covered less than k times, and assigns the counted number to coverageNum[x] (step S11). Then, based on DAS position candidate x and the selected DAS position, the DAS position selection unit 18 calculates XAS for all UE positions using the DAS-UE distance list, DAS-UE angle list, and DAS coverage availability list. The DAS position selection unit 18 calculates the average of the calculated XAS and assigns the calculated value to meanXAS[x] (step S12). Then, the process returns to step S10.

[0039] On the other hand, if x is not less than or equal to X (step S10, No), the DAS position selection unit 18 normalizes coverageNum and meanXAS so that the maximum is 1 (step S13). Next, the DAS position selection unit 18 weights and adds the normalized values ​​of coverageNum and meanXAS to calculate an evaluation value (step S14). Next, the DAS position selection unit 18 selects the DAS position candidate with the maximum evaluation value and adds it to a selected DAS list (not shown) (step S15). This completes the station placement design process shown in Figures 3 and 4.

[0040] In this embodiment, the Greedy algorithm is used as the optimization method, and in step S04, which corresponds to the processing of the DAS-UE propagation path calculation unit 16 in the flowchart of FIG. 3, only the presence or absence of line of sight is determined. However, the present invention is not limited to this configuration. In the present invention, any method can be used as the optimization method. In addition, when the DAS-UE propagation path calculation unit 16 performs ray tracing or the like between the DAS and the UE and calculates the direct wave, reflected wave, diffracted wave, and scattered wave, the angular spread (AS) may be calculated based on the calculated angle of arrival of the ray, and the function X may be calculated based on the propagation path length of the ray, thereby calculating XAS. In this case, a threshold value set based on the value of the received power of the ray may be used to determine whether coverage by the DAS is possible.

[0041] As described above, the station location design device 1 according to one embodiment of the present invention arranges distributed antennas in a high-frequency band distributed MIMO system. The station location design device 1 takes an approach to the k-coverage problem when arranging the distributed antennas, thereby enabling the distributed antennas to be arranged to cover a desired area while minimizing the number of deployed antennas. Furthermore, the station location design device 1 introduces angular spread (AS) as an objective function when taking an approach to the k-coverage problem. This allows the station location design device 1 to spatially distribute and arrange distributed antennas in high-frequency band distributed MIMO, thereby improving robustness against shadowing and reducing spatial correlation of the MIMO channel.

[0042] As described above, the present invention makes it possible to more effectively distribute and arrange distributed antennas while suppressing increases in costs.

[0043] According to the above-described embodiment, the station location design device includes an area setting unit, an antenna position candidate setting unit, a terminal position setting unit, a distance calculation unit, an angle calculation unit, a propagation path calculation unit, a determination unit, and a selection unit. For example, the station location design device is the station location design device 1 in the embodiment, the area setting unit is the area setting unit 11 in the embodiment, the antenna position candidate setting unit is the distributed antenna (DAS) position candidate setting unit 12 in the embodiment, the terminal position setting unit is the user equipment (UE) position setting unit 13 in the embodiment, the distance calculation unit is the DAS-UE distance calculation unit 14 in the embodiment, the angle calculation unit is the DAS-UE angle calculation unit 15 in the embodiment, the propagation path calculation unit is the DAS-UE propagation path calculation unit 16 in the embodiment, the determination unit is the coverable UE determination unit 17 of each DAS in the embodiment, and the selection unit is the DAS position selection unit 18 in the embodiment.

[0044] The area setting unit sets an area for performing station placement design. The antenna position candidate setting unit sets multiple antenna position candidates, which are candidate installation positions for distributed antennas in the area. For example, the antenna position candidates are DAS position candidates in the embodiment. The terminal position setting unit sets multiple terminal positions, which are positions where terminal devices can be located in the area. For example, the terminal positions are UE positions in the embodiment. The distance calculation unit calculates the distance between the antenna position candidate and the terminal position for each combination of the multiple antenna position candidates and the multiple terminal positions. The angle calculation unit calculates the azimuth angle of the antenna position candidate as seen from the terminal position for each combination of the multiple antenna position candidates and the multiple terminal positions. The propagation path calculation unit calculates the propagation path for each combination of the multiple antenna position candidates and the multiple terminal positions. The determination unit determines whether the antenna position candidate is a terminal position that can be covered, based on the distance calculated by the distance calculation unit and the propagation path calculated by the propagation path calculation unit. The selection unit selects installation positions of the distributed antennas based on the result of the determination by the determination unit so that all terminal positions are covered by at least a predetermined number of antenna position candidates, while maximizing an objective function using the angle spread of the azimuth angle calculated by the angle calculation unit. For example, the objective function is maximization of XAS, which is the product of the angle spread (AS) σ(φm) of the angle φm of the DAS position candidate as seen from the UE position in this embodiment, and a function X(dm) of the distance vector dm between the UE and the DAS.

[0045] In the above-described station location design device, the propagation path calculation unit may calculate the propagation path based on whether there is line of sight between the antenna position candidate and the terminal position.

[0046] Part or all of the configuration of the station location design device 1 in the above-described embodiment may be implemented by a computer. In this case, a program for implementing this function may be recorded on a computer-readable recording medium, and the program may be loaded into a computer system and executed. Note that the term "computer system" as used herein includes hardware such as an OS and peripheral devices. Furthermore, the term "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, as well as storage devices such as hard disks built into a computer system. Furthermore, the term "computer-readable recording medium" may also include media that dynamically store programs for a short period of time, such as communication lines used when transmitting programs via networks such as the Internet or communication lines such as telephone lines, or media that store programs for a fixed period of time, such as volatile memory within a computer system that serves as a server or client. The program may be for implementing part of the above-described functions, or may be capable of implementing the above-described functions in combination with a program already stored in the computer system, or may be implemented using a programmable logic device such as an FPGA (Field Programmable Gate Array).

[0047] Although an embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and includes designs within the scope of the gist of the present invention.

[0048] REFERENCE SIGNS LIST 1 Station placement design device 11 Area setting unit 12 Distributed antenna (DAS) position candidate setting unit 13 User equipment (UE) position setting unit 14 DAS-UE distance calculation unit 15 DAS-UE angle calculation unit 16 DAS-UE propagation path calculation unit 17 Coverable UE determination unit for each DAS 18 DAS position selection unit

Claims

1. An area setting unit that sets an area for which station placement design is performed; an antenna position candidate setting unit that sets multiple antenna position candidates, which are candidate installation positions for distributed antennas in the area; a terminal position setting unit that sets multiple terminal positions, which are positions where terminal devices can be located in the area; a distance calculation unit that calculates the distance between each of the antenna position candidates and each of the terminal positions for all combinations of the multiple antenna position candidates and each of the terminal positions; an angle calculation unit that calculates the azimuth angle of each of the antenna position candidates as seen from each of the terminal positions for all combinations of the multiple antenna position candidates and each of the terminal positions; a propagation path calculation unit that calculates each of the propagation paths for each of the combinations of the multiple antenna position candidates and each of the terminal positions; and a determination unit that determines whether each of the antenna position candidates is a terminal position that can be covered based on the distance calculated by the distance calculation unit and the propagation path calculated by the propagation path calculation unit. a selection unit that selects installation positions of the distributed antennas based on a result of the determination by the determination unit so that all of the terminal positions are covered by a predetermined number or more of the antenna position candidates, and so that an objective function using an angle spread of the azimuth angles calculated by the angle calculation unit is maximized.

2. The station location design device according to claim 1, wherein the propagation path calculation unit calculates the propagation path based on whether there is line of sight between the antenna position candidate and the terminal position.

3. A station placement design method executed by a computer, comprising: an area setting step of setting an area for station placement design; an antenna position candidate setting step of setting a plurality of antenna position candidates which are candidate installation positions for distributed antennas in the area; a terminal position setting step of setting a plurality of terminal positions which are positions where terminal devices may be present in the area; a distance calculation step of calculating a distance between each of the antenna position candidates and each of the terminal positions for all combinations of the plurality of antenna position candidates and each of the terminal positions; an angle calculation step of calculating an azimuth angle of each of the antenna position candidates as seen from each of the terminal positions for all combinations of the plurality of antenna position candidates and each of the terminal positions; a propagation path calculation step of calculating a propagation path for each of the combinations of the plurality of antenna position candidates and each of the terminal positions; and a determination step of determining whether each of the antenna position candidates is a terminal position that can be covered based on the distance calculated in the distance calculation step and the propagation path calculated in the propagation path calculation step. a selection step of selecting installation positions of the distributed antennas based on a result of the determination in the determination step, so that all of the terminal positions are covered by a predetermined number or more of the antenna position candidates, and so that an objective function using an angle spread of the azimuth angles calculated in the angle calculation step is maximized.

4. A computer includes an area setting step for setting an area for performing station placement design; an antenna position candidate setting step for setting a plurality of antenna position candidates which are candidate installation locations for distributed antennas in the area; a terminal position setting step for setting a plurality of terminal positions which are locations where terminal devices may be present in the area; a distance calculation step for calculating the distance between the antenna position candidate and the terminal position for all combinations of the plurality of antenna position candidates and the plurality of terminal positions; an angle calculation step for calculating the azimuth angle of the antenna position candidate as seen from the terminal position for all combinations of the plurality of antenna position candidates and the plurality of terminal positions; a propagation path calculation step for calculating the propagation path for all combinations of the plurality of antenna position candidates and the plurality of terminal positions; and a determination step for determining whether the antenna position candidate is a terminal position that can be covered based on the distance calculated in the distance calculation step and the propagation path calculated in the propagation path calculation step. a selection step of selecting installation positions of the distributed antennas so that an objective function using an angle spread of the azimuth angles calculated in the angle calculation step is maximized while all of the terminal positions are covered by a predetermined number or more of the antenna position candidates based on the result of the determination in the determination step.

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