Station installation design system, station installation design device, station installation design method, and program

Abstract

In order to provide a station installation design system that facilitates increased reliability of a wireless base station against failures while controlling installation and operation costs, a station installation design system according to the present invention designs the installation locations of wireless base stations for constructing a wireless area and comprises: a calculation unit that calculates, for each candidate site for an installation location of the wireless base stations, a prescribed objective function from a terminal coverage rate during normal operation and a terminal coverage rate when a failure occurs in the wireless base stations; and a determination unit that determines the installation locations of the wireless base stations such that two wireless base stations can be installed at each candidate site for the installation locations of the wireless base stations, and so as to maximize the objective function.

Description

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

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

[0002] There are station placement design systems that design the installation positions of wireless base stations to construct wireless coverage areas. Furthermore, as the usage patterns of wireless communication systems continue to diversify, an increase in usage patterns that require higher reliability than conventional wireless communication networks, such as in factories and logistics warehouses, is expected (see, for example, Non-Patent Document 1). Furthermore, a technology is known that temporarily changes the tilt angle of base station antennas around a failed wireless base station until the failed wireless base station is fully restored, thereby covering an area where communication is interrupted (see, for example, Non-Patent Document 2).

[0003] Nippon Telegraph and Telephone East Corporation, "What is Local 5G? Explaining how to introduce it in factories and examples," [online], [searched November 27, 1993], Internet<URL: https: / / business.ntt-east.co.jp / bizdrive / column / dr00120-004.html> Iwamoto et al., "Efforts on Automating Tilt Control of Wireless Base Station Antennas," Operations Research Society of Japan, [online], [Retrieved November 27, 1993], Internet<https: / / orsj.org / nc2022s / wp-content / uploads / sites / 12 / 2022 / 03 / 2022s-1-F-2.pdf> .

[0004] The technology disclosed in Non-Patent Document 2 has a problem in that it cannot be applied to wireless base stations that do not support changes to the tilt angle of the base station antenna. Also, while a method of increasing reliability against base station failures by arranging base stations in duplicate is conceivable, duplicating all base stations would double the number of installed base stations, resulting in problems such as increased installation and operation costs.

[0005] As described above, with conventional technology, it has been difficult to increase reliability against failures in wireless base stations while suppressing installation and operation costs.

[0006] An embodiment of the present invention has been made in consideration of the above-mentioned problems, and provides a station placement design system that makes it easy to increase reliability against failures of radio base stations while reducing installation and operating costs.

[0007] In order to solve the above problems, a station location design system according to an embodiment of the present invention is a station location design system that designs installation locations of wireless base stations for constructing a wireless area, and includes: a calculation unit that calculates a predetermined objective function at each candidate installation location of the wireless base station from a terminal coverage rate under normal conditions and a terminal coverage rate when a failure occurs in the wireless base station; and a determination unit that enables installation of two wireless base stations at each candidate installation location of the wireless base station and determines installation locations of the wireless base stations so as to maximize the objective function.

[0008] According to an embodiment of the present invention, it is possible to provide a station placement design system that makes it easy to increase reliability against failures of radio base stations while suppressing installation and operation costs.

[0009] FIG. 1 is a diagram showing an example of the configuration of a station placement design system according to the present embodiment; FIG. 2 is a flowchart showing an example of station placement design processing according to the present embodiment; FIG. 3 is a diagram showing an example of a design target area according to the present embodiment; FIG. 4 is a diagram showing an image of an average coverage rate when a failure occurs according to the present embodiment; FIG. 5 is a diagram showing an example of installation of a radio base station according to the present embodiment; and FIG. 6 is a diagram showing an example of the hardware configuration of a computer according to the present embodiment.

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The embodiment described below is merely an example, and the embodiment to which the present invention is applied is not limited to the following embodiment.

[0011] <Configuration Example of Station Placement Design System> Fig. 1 is a diagram showing a configuration example of a station placement design system according to this embodiment. The station placement design system 1 is a system that performs station placement design, which designs appropriate installation positions of wireless base stations for constructing a wireless area, based on input design conditions. In the example of Fig. 1, the station placement design system 1 includes a station placement design device 100 and a terminal device 110 that can communicate with the station placement design device 100.

[0012] The station location design device 100 is an information processing device having a computer configuration, or a system including multiple computers. The station location design device 100 realizes each functional configuration shown in Fig. 1 by, for example, a computer included in the station location design device 100 executing a program stored in a storage medium. In the example of Fig. 1, the station location design device 100 has each functional configuration, such as an area setting unit 101, an arrangement unit 102, a received power calculation unit 103, a calculation unit 104, a determination unit 105, a communication unit 106, an input / output unit 107, and a storage unit 108. Note that at least a portion of each of the above functional configurations may be realized by hardware.

[0013] The area setting unit 101 executes an area setting process to set a wireless area to be designed (hereinafter referred to as a design target area). The design target area includes, for example, objects such as walls, desks, and shelves that serve as shields. For example, the area setting unit 101 may set the wireless area to be designed based on a building database (DB) representing the structure of a building or three-dimensional computer-aided design (CAD) data. Alternatively, the area setting unit 101 may set the wireless area to be designed based on three-dimensional data acquired by a three-dimensional sensor such as a light detection and ranging (LiDAR) or a depth camera.

[0014] The placement unit 102 executes placement processing to place multiple terminal positions (hereinafter referred to as terminals), which are evaluation points for evaluating received power, and multiple candidate installation locations for wireless base stations (hereinafter referred to as candidate points), within the design area.

[0015] The received power calculation unit 103 executes a received power calculation process to calculate the received power received from the wireless base station installed at the candidate point by the multiple terminals arranged by the arrangement unit 102. For example, the received power calculation unit 103 calculates the received power received by each terminal from the wireless base station installed at the candidate point using a known radio wave propagation simulation technique such as ray tracing.

[0016] The calculation unit 104 executes a calculation process for calculating a predetermined objective function from the terminal coverage rate in normal times and the terminal coverage rate when a failure occurs in the wireless base station at each candidate point for the installation location of the wireless base station.

[0017] For example, the calculation unit 104 calculates the objective function shown in the following equation (1).

[0018] Here, α and β are coefficients, and the normal coverage rate is a value indicating the proportion of terminals that achieve the target received power among multiple terminals in normal times when no failure occurs in the radio base station, for example, while the average coverage rate when a failure occurs is the average proportion of terminals that achieve the target received power among multiple terminals in the event of a failure in the radio base station.

[0019] The determination unit 105 performs a determination process of determining the installation positions of the radio base stations so as to maximize the objective function calculated by the calculation unit 104, while allowing two radio base stations to be placed at each candidate point for the installation positions of the radio base stations. For example, the determination unit 105 determines the installation positions of the radio base stations using a greedy method so as to maximize the objective function. However, the present invention is not limited to this, and the determination unit 105 may determine the installation positions of the radio base stations so as to maximize the objective function using other methods such as a full search, a dynamic programming method, or a local search method.

[0020] The communication unit 106 executes, for example, a communication process for communicating with other devices such as the terminal device 110. The input / output unit 107 executes, for example, an output process for outputting the installation positions of the wireless base stations determined by the determination unit 105 to the terminal device 110, and an input process for receiving input of design conditions and the like from the terminal device 110.

[0021] The memory unit 108 stores various data including, for example, data on the design area set by the area setting unit 101, data on multiple terminals and multiple candidate points placed by the placement unit 102, data on the received power calculated by the received power calculation unit 103, etc.

[0022] The terminal device 110 is an information terminal having a computer configuration that is used by a person in charge of station placement design, etc. The person in charge uses the terminal device 110 to input design conditions and the like to the station placement design device 100, and to display the design results of the installation positions of radio base stations output by the station placement design device 100.

[0023] The configuration of the station location design system 1 shown in Fig. 1 is an example. For example, the functional components of the station location design device 100 in Fig. 1 may be distributed among multiple information processing devices. Furthermore, the station location design device 100 may input design conditions and display the design results of the installation positions of radio base stations without using the terminal device 110.

[0024] <Processing Flow> Next, the processing flow of the station placement design method according to this embodiment will be described.

[0025] 2 is a flowchart showing an example of the station placement design process according to this embodiment. This process shows an example of the station placement design process executed by the station placement design system 1 described with reference to FIG.

[0026] In step S201, the area setting unit 101 sets a design target area. As an example, the area setting unit 101 sets a design target area 300 indoors where a plurality of shielding objects 301 are arranged, as shown in Fig. 3. The design target area 300 set by the area setting unit 101 has three-dimensional coordinates based on, for example, three-dimensional CAD data or three-dimensional data acquired by a three-dimensional sensor.

[0027] In step S202, the placement unit 102 places a plurality of evaluation points (hereinafter referred to as terminals 302) for evaluating wireless quality such as received power, within the design area 300 set by the area setting unit 101, as shown in Fig. 3 for example. The placement unit 102 also places a plurality of candidate points 303, which are candidates for installation locations of wireless base stations, within the design area 300, as shown in Fig. 3 for example. In this embodiment, up to two wireless base stations can be placed at each candidate point 303.

[0028] In step S203, the station placement design system 1 installs a radio base station at each candidate point 303 and calculates an objective function from the received power of all terminals 302 in the cases where there is no failure and where there is a failure. For example, the received power calculation unit 103 calculates the received power received by each terminal 302 when a radio base station is installed at each candidate point 303. Furthermore, the calculation unit 104 calculates the objective function when a radio base station is installed at each candidate point 303 using the above-mentioned equation (1) based on the received power calculated by the received power calculation unit 103.

[0029] For example, the calculation unit 104 calculates the coverage rate in normal times when a wireless base station is installed at each candidate point 303, from the received power calculated by the received power calculation unit 103. For example, the calculation unit 104 calculates the proportion of terminals 302 whose received power exceeds the target received power among the multiple terminals 302, and sets this as the coverage rate in normal times.

[0030] Furthermore, the calculation unit 104 calculates the average coverage rate in the event of a failure when a wireless base station is installed at each candidate point 303, from the received power calculated by the received power calculation unit 103. For example, as shown in Fig. 4, it is assumed that three wireless base stations 401 are installed in the design area 300, and there are failure pattern 1 in which wireless base station 403 fails, failure pattern 2 in which wireless base station 401 fails, and failure pattern 3 in which wireless base station 402 fails.

[0031] In this case, the calculation unit 104 calculates the proportion of terminals 302 that achieve the target received power among the multiple terminals 302 in failure pattern 1, and sets this as the coverage rate for failure pattern 1. Furthermore, the calculation unit 104 calculates the proportion of terminals 302 that achieve the target received power among the multiple terminals 302 in failure pattern 2, and sets this as the coverage rate for failure pattern 2. Similarly, the calculation unit 104 calculates the proportion of terminals 302 that achieve the target received power among the multiple terminals 302 in failure pattern 3, and sets this as the coverage rate for failure pattern 3. Furthermore, the calculation unit 104 sets the average of the coverage rates for failure pattern 1, failure pattern 2, and failure pattern 3 as the average coverage rate at the time of failure occurrence.

[0032] The calculation unit 104 calculates the objective function according to the above-mentioned formula (1) using the calculated average of the normal cover rate and the cover rate when a failure occurs.

[0033] In step S204, the determining unit 105 determines the candidate point 303 at which the objective function calculated by the calculating unit 104 is maximized as the installation position of the wireless base station.

[0034] The processes in steps S203 and S204 can be expressed as an optimization problem mathematically formulated using the objective function of the following equation (2) and constraint conditions.

[0035] Here, i is the terminal ∀i∈I, j is the base station ∀j∈J, j' is the failed base station ∀j′∈J, n is the station placement plan ∀n∈N, α and β are counts, r ｉｊ is the received power that terminal i receives from base station j. ｉ，ｎ is the maximum received power (normal) received by terminal i in channel placement design plan n, p ｉｊ'，ｎ is the maximum received power (when a failure occurs) that terminal i receives in the channel placement plan n, and p ｔ１ is the target received power (normal), p ｔ２ is the target received power (when a fault occurs), z ｉ，ｎ is the target reception power achievement level (normal), y ｉｊ'，ｎ is the target received power achievement rate (when a failure occurs).

[0036] In step S205, the station placement design system 1 determines whether or not predetermined design conditions are satisfied. For example, the station placement design system 1 determines that the predetermined design conditions are satisfied when a predetermined proportion q of the terminals 302 have normal reception power that exceeds the target normal reception power and have failure-occurring reception power that exceeds the target failure-occurring reception power.

[0037] If the predetermined design conditions are not satisfied, the station placement design system 1 moves the process to step S206. On the other hand, if the predetermined design conditions are satisfied, the station placement design system 1 ends the process of FIG.

[0038] When the process proceeds to step S206, the station placement design system 1 increases the number of stations to be placed and returns the process to step S203. As a result, the station placement design system 1 executes the processes from step S203 again with the radio base station installed at the installation position determined in step S204. As described above, in this embodiment, up to two radio base stations can be placed at each candidate point 303.

[0039] The processing in steps S203 to S206 is an example of processing for determining the installation positions of wireless base stations by a greedy method so as to maximize a predetermined objective function.

[0040] Fig. 5 is a diagram showing an example of the installation of a wireless base station according to this embodiment. This diagram shows an image in which a wireless base station 501 is installed in the design area 300 described in Fig. 3 at the installation position determined by the processing in Fig. 2. Of the multiple wireless base stations 501, a wireless base station 501a is installed as a duplicate wireless base station.

[0041] In this way, the station location design system 1 according to this embodiment can thoroughly place wireless base stations, including dual installation of wireless base stations, in the area 502 where the influence of the obstruction 301 is large. Furthermore, the station location design system 1 can efficiently cover the wireless area with a smaller number of wireless base stations in the area 503 where the influence of the obstruction 301 is small.

[0042] (Application Example) In the above description, the received signal strength at each terminal 302 is used as a criterion as an objective function in station placement design, but other criteria may also be used, such as a signal-to-interference and noise ratio, throughput, etc. In this case, estimated values ​​based on the received signal strength may be used for the signal-to-interference and noise ratio, throughput, etc.

[0043] Although the above description has been given of station placement design for a single wireless system, this embodiment can also be applied to station placement design that combines multiple wireless systems, for example, in combination with the following reference: (Reference: Toshiro Nakahira, Daisuke Murayama, Satoshi Takatani, Kenichi Kawamura, Takatsune Moriyama, "Multi-Wireless Area Design Method Based on Communication Capacity and Base Station Cost," IEICE Techniques, Institute of Electronics, Information and Communication Engineers General Conference, B-5-97, Mar. 2022.)

[0044] <Hardware Configuration> (Hardware Configuration of Station Placement Design Device) The station placement design device 100 and the terminal device 110 according to this embodiment have, for example, the hardware configuration of a computer 600 as shown in Fig. 6. Alternatively, the station placement design device 100 is realized by a plurality of computers 600.

[0045] 6 is a diagram showing an example of the hardware configuration of a computer according to this embodiment. In the example of Fig. 6, a computer 600 includes a processor 601, a memory 602, a storage device 603, a communication device 604, an input device 605, an output device 606, and a bus B.

[0046] The processor 601 is, for example, an arithmetic unit such as a CPU (Central Processing Unit) that executes predetermined programs to realize various functions. The memory 602 is a storage medium readable by the computer 600, and includes, for example, a RAM (Random Access Memory) and a ROM (Read Only Memory). The storage device 603 is a computer-readable storage medium, and may include, for example, a HDD (Hard Disk Drive), an SSD (Solid State Drive), various optical disks, and magneto-optical disks.

[0047] The communication device 604 includes one or more pieces of hardware (communication devices) for communicating with other devices via a wireless or wired network. The input device 605 is an input device (e.g., a keyboard, a mouse, a microphone, a switch, a button, a sensor, etc.) that receives input from the outside. The output device 606 is an output device (e.g., a display, a speaker, an LED lamp, etc.) that outputs to the outside. Note that the input device 605 and the output device 606 may be integrated into one device (e.g., an input / output device such as a touch panel display).

[0048] The bus B is commonly connected to the above components and transmits, for example, address signals, data signals, and various control signals. The processor 601 is not limited to a CPU, and may be, for example, a DSP (Digital Signal Processor), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array).

[0049] (Supplementary Note) The station location design device 100 in this embodiment is not limited to being realized by a dedicated device, but may also be realized by a general-purpose computer. In this case, a program for realizing this function may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be read into a computer system and executed to realize the function. Note that the term "computer system" here includes hardware such as an OS and peripheral devices.

[0050] Furthermore, "computer-readable recording media" includes various storage devices such as portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, as well as hard disks built into computer systems. Furthermore, "computer-readable recording media" may also include devices that dynamically store programs for a short period of time, such as communication lines when transmitting programs via networks such as the Internet or communication lines such as telephone lines, and devices that store programs for a certain period of time, such as volatile memory within computer systems that serve as servers or clients in such cases.

[0051] Furthermore, the above program may be one that realizes part of the above-mentioned functions, or may be one that can realize the above-mentioned functions in combination with a program already recorded in a computer system, or may be one that is realized using hardware such as a PLD (Programmable Logic Device) or FPGA (Field Programmable Gate Array).

[0052] <Effects of the embodiment> According to the present embodiment, it is possible to provide a station placement design system 1 that makes it easy to increase reliability against failures in radio base stations while suppressing installation and operation costs.

[0053] For example, the station placement design system 1 of this embodiment can derive, with a small amount of calculation, a radio station placement design in which, depending on the radio environment, base station placement is duplicated where necessary, while locations where efficient coverage is possible are covered with a smaller number of base stations.

[0054] Summary of Embodiments This specification discloses at least the following station location design system, station location design device, station location design method, and program: (Item 1) A station location design system that designs installation positions of wireless base stations to establish a wireless area, the system comprising: a calculation unit that calculates a predetermined objective function at each candidate point for the installation positions of the wireless base stations from a terminal coverage rate in normal times and a terminal coverage rate when a failure occurs in the wireless base station; and a determination unit that enables installation of two wireless base stations at each candidate point for the installation positions of the wireless base stations and determines installation positions of the wireless base stations so as to maximize the objective function. (Clause 2) A station location design device that designs installation locations of wireless base stations to construct a wireless area, comprising: a calculation unit that calculates a predetermined objective function at each candidate point for the installation locations of the wireless base stations from a terminal coverage rate under normal conditions and the terminal coverage rate when a failure occurs in the wireless base station; and a determination unit that allows two wireless base stations to be installed at each candidate point for the installation locations of the wireless base stations and determines the installation locations of the wireless base stations so as to maximize the objective function. (Clause 3) A station location design method in which a computer that designs installation locations of wireless base stations to construct a wireless area, allows two wireless base stations to be installed at each candidate point for the installation locations of the wireless base stations, calculates a predetermined objective function at each candidate point for the installation locations of the wireless base stations from a terminal coverage rate under normal conditions and the terminal coverage rate when a failure occurs in the wireless base station, and determines the installation locations of the wireless base stations so as to maximize the objective function. (Clause 4) A program that causes a computer to execute the station location design method described in clause 3.

[0055] Although the present embodiment has been described above, the present invention is not limited to such a specific embodiment, and various modifications and changes are possible within the scope of the gist of the present invention described in the claims.

[0056] REFERENCE SIGNS LIST 1 Station placement design system 100 Station placement design device 101 Area setting unit 102 Placement unit 103 Received power calculation unit 104 Calculation unit 105 Determination unit 303 Candidate point 600 Computer

Claims

1. A station placement design system for designing the installation positions of radio base stations for constructing a radio area, comprising: a calculation unit that calculates a predetermined objective function from the normal terminal coverage rate and the terminal coverage rate when a failure occurs in the radio base station at each candidate point of the installation position of the radio base station; and a determination unit that enables two of the radio base stations to be installed at each candidate point of the installation position of the radio base station and determines the installation position of the radio base station so as to maximize the objective function.

2. A station placement design apparatus for designing the installation positions of radio base stations for constructing a radio area, comprising: a calculation unit that calculates a predetermined objective function from the normal terminal coverage rate and the terminal coverage rate when a failure occurs in the radio base station at each candidate point of the installation position of the radio base station; and a determination unit that enables two of the radio base stations to be installed at each candidate point of the installation position of the radio base station and determines the installation position of the radio base station so as to maximize the objective function.

3. A computer for designing the installation positions of radio base stations for constructing a radio area, enabling two of the radio base stations to be installed at each candidate point of the installation position of the radio base station, calculating a predetermined objective function from the normal terminal coverage rate and the terminal coverage rate when a failure occurs in the radio base station at each candidate point of the installation position of the radio base station, and determining the installation position of the radio base station so as to maximize the objective function.

4. A program for causing a computer to execute the station placement design method according to claim 3.

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