Installation position determination method and installation position determination system

Abstract

To efficiently determine the installation position of a relay station such that signals can be propagated with predetermined quality even when the distance from a base station to a terminal is long or when there is a terminal out of line of sight from the base station.SOLUTION: A base station coverage area in which a base station can transmit signals with a predetermined quality is identified S202, each AF relay station coverage area in which an AF relay station can amplify and relay the signal with a predetermined quality is identified S204 when the AF relay station is installed at each of multiple candidate locations for AF relay station installation locations, the base station coverage area and the AF relay station coverage area are individually overlapped S206, and one candidate position with the maximum coverage area in which the signal transmitted by the base station can be propagated with a predetermined quality is determined as the installation position of the AF relay station S210.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a method and system for determining the installation position of a relay station that can amplify and relay a signal transmitted by a base station that performs wireless communication. [Background technology]

[0002] Wireless communication using high frequency bands such as millimeter waves can achieve wideband and large-capacity communication, but it has higher propagation loss than wireless communication using low frequency bands.

[0003] In wireless communications using high frequency bands, it can be difficult to ensure sufficient communication quality for terminals (user terminals) located far from the base station. In addition, in wireless communications using high frequency bands, the impact of blocking is significant, making it difficult to establish wireless communications with terminals outside the line of sight of the base station.

[0004] For example, in urban areas with many buildings or complex roads, a huge number of base stations would be required to ensure sufficient communication quality. In such cases, it is desirable to efficiently place relay stations.

[0005] Conventionally, several station placement methods have been known that consider the placement of base stations to ensure the quality of wireless communication (see, for example, Non-Patent Document 1). However, there have been few studies on station placement methods that target relay stations. For example, a method is known in which relay stations are placed so as to maximize communication capacity based on the distance from the base station to the relay station (see, for example, Non-Patent Document 2). [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] Kei Fukunaga and two others, "Study on Alternative Network Deployment Methods Using UAV Aerial Base Stations in Case of Base Station Outages in Urban Areas," 81st National Convention of Information Processing Society of Japan, 2019, 5V-06, pp.3-69~3-70 [Non-patent document 2] Weisi Guo and Tim O'Farrell, "Relay Deployment in Cellular Networks: Planning and Optimization", IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, VOL. 31, NO. 8, AUGUST 2013, p.1597-1606 Summary of the Invention [Problem to be solved by the invention]

[0007] However, conventional relay station placement methods do not take into account objects present in the environment, nor the effects of occlusion into account. The relay station according to the present application is an AF (Amplify-and-Forward) relay station (hereinafter referred to as an AF relay station) that does not have modulation / demodulation functions but has an amplification function, amplifies received signals, and transmits them to minimize delay.

[0008] The present invention aims to provide an installation position determination method and system that can efficiently determine the installation position of a relay station that relays signals so that signals can be propagated with a predetermined quality even when the distance from the base station to the terminal is long or when the terminal is out of line of sight from the base station. [Means for solving the problem]

[0009] The installation position determination method according to one aspect of the present invention determines the installation position of an AF relay station that can amplify and relay a signal transmitted by a base station. , the installation position determination system executes multiple processes. In the installation position determination method, The plurality of steps include:a first specifying step of specifying a base station coverage area where the base station can transmit signals with a predetermined quality; a second specifying step of specifying an AF relay station coverage area where the AF relay station can amplify and relay signals with the predetermined quality when an AF relay station is installed at each of a plurality of candidate locations for the AF relay station installation location; a determination step of individually superimposing the base station coverage area and each of the AF relay station coverage areas to determine, as the installation location of the AF relay station, one of the candidate locations where the coverage area over which the signal transmitted by the base station can propagate with the predetermined quality is largest; and a control step of individually superimposing the coverage areas over which the signal can propagate with the predetermined quality by the base station and an AF relay station installed at the determined installation location with each of the AF relay station coverage areas specified in the second specifying step other than the determined installation location, to determine, as the installation location of the AF relay station, another of the candidate locations where the coverage area over which the signal transmitted by the base station can propagate with the predetermined quality is largest.

[0010] Furthermore, an installation position determination system according to one aspect of the present invention is an installation position determination system that determines the installation position of an AF relay station that can amplify and relay a signal transmitted by a base station, the installation position determination system including: a first specifying unit that specifies a base station coverage area where the base station can transmit a signal with a predetermined quality; a second specifying unit that specifies, when an AF relay station is installed at each of a plurality of candidate locations that are candidates for the installation position of the AF relay station, an AF relay station coverage area where the AF relay station can amplify and relay a signal with a predetermined quality; and a second specifying unit that individually superimposes the base station coverage area and the AF relay station coverage area to determine the installation position of an AF relay station that can amplify and relay a signal transmitted by the base station. The present invention is characterized in that it has a determination unit that determines one of the candidate locations with the largest coverage area in which signals can be propagated with a predetermined quality as an installation location for an AF relay station, and a control unit that controls the determination unit to individually superimpose the coverage areas in which signals can be propagated with a predetermined quality by the base station and an AF relay station installed at the installation location determined by the determination unit with each of the AF relay station coverage areas identified by the second identification unit other than the installation location determined by the determination unit, and to further determine another of the candidate locations with the largest coverage area in which signals transmitted by the base station can be propagated with a predetermined quality as an installation location for an AF relay station. [Effects of the Invention]

[0011] According to the present invention, even when the distance from the base station to the terminal is long or when the terminal is out of the line of sight of the base station, it is possible to efficiently determine the installation location of a relay station that will relay signals so that signals can be propagated with a predetermined quality. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 2 is a conceptual diagram conceptually illustrating a process performed by an installation position determination system according to an embodiment. [Figure 2] FIG. 2 is a functional block diagram illustrating functions of an installation position determination system according to an embodiment. [Figure 3] FIG. 10 is a diagram illustrating an example of a process performed by the installation position determination system according to an embodiment to determine the position of one AF relay station. [Figure 4]FIG. 10 is a diagram illustrating an example of a process performed by an installation position determination system according to an embodiment to determine installation positions of a plurality of AF relay stations. [Figure 5] FIG. 1 illustrates an example of a hardware configuration of an installation position determination system according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] An installation position determining system according to an embodiment will be described below with reference to the drawings: Fig. 1 is a conceptual diagram conceptually showing the processing performed by the installation position determining system according to an embodiment.

[0014] It should be noted that the installation location determination system according to one embodiment is a system that does not have a modulation / demodulation function but has an amplification function, and determines the installation location of an AF (Amplify-and-Forward) relay station (AF relay station), which receives and amplifies millimeter wave signals transmitted by a base station, for example, and transmits (relays) them with minimal delay.

[0015] An AF relay station is a low-cost, low-latency, low-power, and compact relay station, such as an analog RS (Relay Station). For example, an analog RS has two sides, a receiving side and a transmitting side, and each side is configured to enable high-performance dynamic beam control using a multi-element antenna.

[0016] The installation position determination system according to one embodiment is configured to efficiently determine the installation positions of AF relay stations, for example, for the purpose of expanding the coverage area in which signals can be propagated with a predetermined quality by base stations and AF relay stations, and for the purpose of preventing blocking.

[0017] First, the installation location determination system creates, for example, a 3D map (area map) to grasp the environment in which a road 200 exists between multiple buildings 100, and then uses a radio wave propagation analysis tool, such as a ray tracing method, to identify the area where only the base station covers radio wave propagation (base station coverage area) (1).

[0018] The base station coverage area is shown by, for example, a color map that colors the radio wave propagation conditions (including communication quality information such as radio wave strength, SNR, and communication capacity).

[0019] Next, when an AF relay station is installed at a location where it can be installed, the installation position determination system identifies each area that will be newly covered by each AF relay station (each AF relay station coverage area) (2).

[0020] For example, a receiving device may be placed at each location where an AF relay station can be installed, and the coverage area of ​​each AF relay station may be specified.

[0021] At this time, since there are limitations on the locations where AF relay stations can be installed, the installation location determination system selects (extracts) a plurality of candidate locations for the installation location of the AF relay station so as to reduce and limit them.

[0022] The coverage area of ​​each AF relay station is also shown by a color map that colors the radio wave propagation conditions (including communication quality information such as radio wave strength, SNR, and communication capacity).

[0023] The installation location determination system then sequentially and individually overlays the base station coverage area and each AF relay station coverage area (3), and displays each area (coverage area) newly covered by the base station and the AF relay station using multiple color maps (coverage color maps) (4).

[0024] Next, the installation location determination system selects one AF relay station location from among the multiple areas (coverage areas) newly covered by the base station and AF relay stations that minimizes the area where the received power by the terminal is below a predetermined threshold, and determines this as the installation location of the first AF relay station (5).

[0025] The installation position determination system then repeats adding AF relay stations (determining installation positions) until the area where the received power by the terminal is below a predetermined threshold becomes a predetermined ratio or less of the area where the signal should be propagated (6).

[0026] In this case, the installation position determination system may locate a transmitter at the installation position of the AF relay station, and identify the coverage areas of the second and subsequent AF relay stations.

[0027] Specifically, the areas of the base station and the selected AF relay station (7) are superimposed on the area newly covered by other AF relay stations (8), and the area (coverage region) covered by the base station and multiple AF relay stations is shown by a color map (coverage color map).

[0028] Next, the functions of the installation position determination system will be described in more detail. Fig. 2 is a functional block diagram illustrating the functions of the installation position determination system according to one embodiment. As shown in Fig. 2, the installation position determination system includes, for example, a first identification unit 10, a selection unit 12, a second identification unit 14, a determination unit 16, and a control unit 18.

[0029] The first identification unit 10 acquires base station and environmental information (such as an area map including buildings and roads), identifies the base station coverage area in which the base station can transmit signals with a specified quality, and outputs the identification results to the second identification unit 14 and the decision unit 16.

[0030] The selection unit 12 acquires information indicating, for example, a plurality of locations where an AF relay station can be installed (such as the rooftop of a building). The selection unit 12 then selects (extracts) locations where the AF relay station can amplify and relay a signal transmitted from a base station with a quality equal to or higher than a predetermined threshold from the plurality of locations where an AF relay station can be installed, as a plurality of candidate locations for the installation location of the AF relay station, and outputs the selection result to the second identification unit 14.

[0031] The second identification unit 14 identifies the AF relay station coverage area in which the AF relay station can amplify and relay signals with a predetermined quality when an AF relay station is installed at each of a plurality of candidate locations for the installation location of the AF relay station, and outputs the identified results to the determination unit 16.

[0032] The determination unit 16 individually superimposes the base station coverage area and each AF relay station coverage area, determines one candidate location that maximizes the coverage area through which the signal transmitted by the base station can propagate with a specified quality as the installation location of the AF relay station, and outputs the determined result to the control unit 18.

[0033] The control unit 18 controls the determination unit 16 to individually superimpose the coverage areas in which signals can be propagated with a predetermined quality by the base station and the AF relay station installed at the installation position determined by the determination unit 16 with each of the AF relay station coverage areas identified by the second identification unit 14 other than the installation position determined by the determination unit 16, and to further determine another candidate position that maximizes the coverage area in which signals transmitted by the base station can be propagated with a predetermined quality as the installation position of the AF relay station.

[0034] In addition, the control unit 18 controls the determination unit 16 to repeatedly determine the installation location of the AF relay station until the non-coverage area, where the signal transmitted from the base station cannot be propagated with a predetermined quality, becomes a predetermined ratio or less to the area where the signal should be propagated.

[0035] Furthermore, the control unit 18 may control the determination unit 16 to repeatedly determine the installation position of the AF relay station until there are at least two or more propagation paths through which the signal transmitted by the base station propagates to the mobile terminal.

[0036] Next, a process performed by the installation position determination system will be described. Fig. 3 is a diagram showing an example of a process performed by the installation position determination system according to an embodiment to determine the position of one AF relay station.

[0037] In step 100 (S100), the installation position determination system sets an area map of the area for which the installation position of the AF relay station is to be determined. For example, the area map is three-dimensional data including the topography, maps, and structures of the target area.

[0038] In step 102 (S102), the installation position determination system sets communication parameters, such as parameters of the base station, AF relay station, and terminal that constitute the wireless communication system (transmission power, antenna, amplifier gain, and other information required for calculation), and parameters of the wireless communication system (frequency, and other information required for calculation).

[0039] In step 104 (S104), the installation position determination system sets the position (three-dimensional coordinates, etc.) of the base station.

[0040] In step 106 (S106), the installation position determination system calculates the communication quality of the area covered by the base station using the setting values ​​of the area map and the setting values ​​of the communication parameters, and calculates the base station coverage area. The communication quality is indicated by, for example, received power, throughput, capacity, delay, error rate, and other values ​​used to evaluate communication quality.

[0041] In step 108 (S108), the installation position determination system sets a plurality of candidate positions (such as three-dimensional coordinates) of the AF relay station.

[0042] In step 110 (S110), the installation position determination system calculates the communication quality of the area covered by each AF relay station when the AF relay station is placed at each of the plurality of candidate positions, and calculates each AF relay station coverage area.

[0043] In step 112 (S112), the installation position determination system determines the installation position of the AF relay station using information on the coverage areas of the base station and the AF relay station.

[0044] 4 is a diagram illustrating an example of a process performed by an installation position determination system according to an embodiment to determine installation positions of multiple AF relay stations. Here, the installation position determination system determines installation positions of the AF relay stations so as to ensure multiple (e.g., two) propagation paths from the base station to the terminal in order to counter blocking.

[0045] In step 200 (S200), the installation position determination system sets the number n of propagation paths from the base station to the terminal to one.

[0046] In step 202 (S202), the installation position determination system obtains a coverage color map of the base station.

[0047] In step 204 (S204), the installation position determination system obtains the coverage color map of each AF relay station.

[0048] In step 206 (S206), the installation position determination system overlays the coverage color maps (color maps) of the respective AF relay stations.

[0049] In step 208 (S208), the installation position determination system selects the position of one AF relay station.

[0050] In step 210 (S210), the installation position determination system determines the position of the selected AF relay station as the installation position of the AF relay station.

[0051] In step 212 (S212), the installation position determination system determines whether the uncovered area, through which a signal transmitted from the base station cannot be propagated with a predetermined quality by the base station and the AF relay station installed at the determined installation position, is a predetermined ratio (e.g., 2%) or less of the area through which the signal should be propagated. If the installation position determination system determines that the ratio is less than the predetermined ratio (S212: Yes), it proceeds to processing of S216, and if the ratio is not less than the predetermined ratio (S212: No), it proceeds to processing of S214.

[0052] In step 214 (S214), the installation position determination system excludes the position of the selected AF relay station from the candidate positions, and returns to the processing of S206.

[0053] In step 216 (S216), the installation position determination system determines whether the number of propagation paths from the base station to the terminal is n=2 or not, and if n=2 (S216: Yes), ends the processing, and if n=2 is not (S216: No), proceeds to processing S218.

[0054] In step 218 (S218), the installation position determination system visualizes, by a color map, areas that are not covered by the radio wave propagation through the two propagation paths.

[0055] In step 220 (S220), the installation position determination system replaces the number n of propagation paths from the base station to the terminal with n+1, and returns to the processing of S204.

[0056] That is, the installation position determination system determines the installation positions of the AF relay stations so as to form a plurality (n paths) of propagation paths (communication paths) by arranging the AF relay stations in order to avoid momentary object obstruction.

[0057] Therefore, the installation position determination system can determine the installation position of the AF relay station so as to form multiple propagation paths from the base station to the terminal more efficiently than by repeating the process shown in FIG. 3 n times.

[0058] In this way, the installation position determination system of one embodiment individually superimposes the coverage areas of the base station and the AF relay station installed at the determined installation position with the coverage areas of AF relay stations other than the determined installation position, and determines another candidate position that maximizes the coverage area in which the signal transmitted by the base station can propagate with a specified quality as the installation position of the AF relay station.Therefore, even when the distance from the base station to the terminal is long or the terminal is out of line of sight from the base station, it is possible to efficiently determine the installation position of the relay station that will relay the signal so that it can propagate with a specified quality.

[0059] In addition, each function of the installation position determination system may be configured in part or in whole by hardware such as a PLD (Programmable Logic Device) or an FPGA (Field Programmable Gate Array), or may be configured as a program executed by a processor such as a CPU.

[0060] For example, the installation position determination system according to the present invention can be realized using one or more computers and programs, and the programs can be recorded on a storage medium or provided via a network.

[0061] Fig. 5 is a diagram showing an example of the hardware configuration of an installation position determination system according to an embodiment. As shown in Fig. 5, for example, the installation position determination system has an input unit 50, an output unit 51, a communication unit 52, a CPU 53, a memory 54, and an HDD 55 connected via a bus 56, and has the functionality of a computer. The installation position determination system is also configured to be able to input and output data to and from a computer-readable storage medium 57.

[0062] The input unit 50 is, for example, a keyboard and a mouse, etc. The output unit 51 is, for example, a display device such as a display, etc. The communication unit 52 is, for example, a wireless network interface.

[0063] The CPU 53 controls each unit constituting the installation position determination system and performs predetermined processing, etc. The memory 54 and HDD 55 correspond to the storage unit 30 described above that stores data, etc. The storage medium 57 is capable of storing programs, etc. that execute the functions of the installation position determination system. Note that the architecture constituting the installation position determination system is not limited to the example shown in FIG. 5. [Explanation of symbols]

[0064] 10 First identification unit, 12 Selection unit, 14 Second identification unit, 16 Decision unit, 18 Control unit, 50 Input unit, 51 Output unit, 52 Communication unit, 53 CPU, 54 Memory, 55 HDD, 56 Bus, 57 Storage medium

Claims

1. In an installation position determination method in which an installation position determination system executes a plurality of steps to determine the installation position of an AF relay station that can amplify and relay a signal transmitted by a base station, The plurality of steps include: a first identification step of identifying a base station coverage area in which the base station can transmit signals with a predetermined quality; a second specifying step of specifying an AF relay station coverage area in which the AF relay station can amplify and relay signals with a predetermined quality when an AF relay station is installed at each of a plurality of candidate locations that are candidates for the installation location of the AF relay station; a determining step of individually superimposing the base station coverage area and the AF relay station coverage area, and determining, as an installation location of the AF relay station, one of the candidate locations where the coverage area that can propagate the signal transmitted by the base station with a predetermined quality is maximized; a control step of individually superimposing a coverage area in which a signal can be propagated with a predetermined quality by the base station and an AF relay station installed at the determined installation position with each of the AF relay station coverage areas identified in the second identification step other than the determined installation position, and performing control so as to further determine, as an installation position for the AF relay station, another one of the candidate positions which maximizes the coverage area in which a signal transmitted by the base station can be propagated with a predetermined quality; An installation position determining method comprising:

2. In the control step, The second specifying step and the determining step are repeated to determine the installation position of the AF relay station until the non-covered area where the signal transmitted from the base station cannot be propagated with a predetermined quality becomes equal to or less than a predetermined ratio to the area where the signal should be propagated.

2. The installation position determining method according to claim 1, wherein:

3. In the control step, and controlling the second specifying step and the determining step to determine the installation position of the AF relay station until there are at least two or more propagation paths through which the signal transmitted from the base station propagates to the mobile terminal.

3. The installation position determining method according to claim 1 or 2, wherein:

4. a selection step of selecting, as the candidate location, a location where the AF relay station can amplify and relay the signal transmitted by the base station with a quality equal to or higher than a predetermined threshold, from among a plurality of locations where the AF relay station can be installed; further comprising In the control step, 3. The installation position determining method according to claim 1, further comprising the step of controlling the selection step, the second specification step, and the determination step to determine the installation position of the AF relay station.

5. In an installation position determination system for determining the installation position of an AF relay station that can amplify and relay a signal transmitted from a base station, a first identification unit that identifies a base station coverage area in which the base station can transmit a signal with a predetermined quality; a second specifying unit that specifies an AF relay station coverage area in which the AF relay station can amplify and relay a signal with a predetermined quality when the AF relay station is installed at each of a plurality of candidate locations that are candidates for the installation location of the AF relay station; a determination unit that individually superimposes the base station coverage area and the AF relay station coverage area, and determines, as an installation location of the AF relay station, one of the candidate locations that maximizes the coverage area through which a signal transmitted by the base station can propagate with a predetermined quality; a control unit that controls the determination unit to individually superimpose a coverage area in which a signal can be propagated with a predetermined quality by the base station and an AF relay station installed at the installation position determined by the determination unit and each of the AF relay station coverage areas identified by the second identification unit other than the installation position determined by the determination unit, and to further determine, as an installation position of the AF relay station, another candidate position that maximizes the coverage area in which a signal transmitted by the base station can be propagated with a predetermined quality; An installation position determination system comprising:

6. The control unit and controlling the determination unit so that the second identification unit and the determination unit repeat operations to determine the installation position of the AF relay station until the non-coverage area where the signal transmitted from the base station cannot be propagated with a predetermined quality becomes equal to or less than a predetermined ratio to the area where the signal should be propagated.

6. The installation position determining system according to claim 5, wherein:

7. The control unit and controlling the second specifying unit and the determining unit to repeat operations and determine the installation position of the AF relay station until there are at least two or more propagation paths through which the signal transmitted from the base station propagates to the mobile terminal.

7. The installation position determining system according to claim 5 or 6, wherein:

8. a selection unit that selects, as the candidate location, a location where the AF relay station can amplify and relay the signal transmitted by the base station with a quality equal to or higher than a predetermined threshold, from among a plurality of locations where the AF relay station can be installed. and The control unit 7. The installation position determination system according to claim 5, wherein the selection unit, the second specification unit, and the determination unit are controlled so that the determination unit determines the installation position of the AF relay station by repeating the operations of the selection unit, the second specification unit, and the determination unit.

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