Wireless communication system, wireless communication method, wireless communication device, and wireless communication program

Abstract

The present disclosure relates to a wireless communication system, a wireless communication method, a wireless communication device, and a wireless communication program. This wireless communication system is provided with an imaging device and a control device. The imaging device is configured to perform a process for capturing an image for learning pertaining to the state of rainfall. The control device is configured to perform: a process for acquiring information relating to rainfall; a process for acquiring a transmission power attenuation amount resulting from rainfall; and a process for creating a model for estimating the transmission power attenuation amount resulting from rainfall on the basis of the image for learning, the information, and the attenuation amount. The imaging device is also configured to perform a process for capturing an image pertaining to the state of rainfall in a relevant environment. The control device is also configured to perform a process for estimating the transmission power attenuation amount in the relevant environment on the basis of the estimation model and the image, and a process for executing wireless communication control based on the result of estimating the attenuation amount.

Description

Wireless communication system, wireless communication method, wireless communication device, and wireless communication program

[0001] The present disclosure relates to a wireless communication system, a wireless communication method, a wireless communication device, and a wireless communication program.

[0002] Rain attenuation is a known phenomenon used in wireless communication simulations. Rain attenuation is a phenomenon in which electromagnetic waves, including radio waves and visible light, are attenuated by rain. For example, Non-Patent Document 1 discloses a technique for calculating the amount of transmission power attenuation due to rain.

[0003] Yoshio Karasawa, "Rain Attenuation Estimation Method for Terrestrial Wireless Links - Progress in Improving the Accuracy of Estimation Methods in Japan and Details of the Current Estimation Methods," March 29, 2019

[0004] However, the above-mentioned technology statistically derives the amount of transmission power attenuation due to rainfall, and is unable to estimate the amount of local attenuation in the target environment. In other words, there is a problem in that it is not possible to control wireless communications according to the current rainfall conditions in the target environment.

[0005] In order to solve the above-mentioned problems, the first objective of the present disclosure is to provide a wireless communication system that can perform wireless communication control according to the current rainfall conditions in the target environment by estimating the amount of ultra-local attenuation due to rain attenuation.

[0006] A second object of the present disclosure is to provide a wireless communication method capable of controlling wireless communication according to the current rainfall conditions in a target environment by estimating the amount of ultra-local attenuation due to rain attenuation.

[0007] A third object of the present disclosure is to provide a wireless communication device that can perform wireless communication control according to the current rainfall conditions in a target environment by estimating the amount of ultra-local attenuation due to rain attenuation.

[0008] A fourth object of the present disclosure is to provide a wireless communication program that can perform wireless communication control according to the current rainfall conditions in a target environment by estimating the amount of ultra-local attenuation due to rain attenuation.

[0009] A first aspect of the present disclosure is preferably a wireless communication system including an imaging device and a control device, wherein the imaging device is configured to perform a process of capturing learning images of rainfall conditions, the control device is configured to perform a process of acquiring information related to rainfall, a process of acquiring the amount of transmission power attenuation due to rainfall, and a process of creating an estimation model of the amount of transmission power attenuation due to rainfall based on the learning images, information, and attenuation, the imaging device is configured to perform a process of capturing images of rainfall conditions in a target environment, and the control device is configured to perform a process of estimating the amount of transmission power attenuation in the target environment based on the estimation model and the images, and a process of performing wireless communication control based on the estimated amount of attenuation.

[0010] Furthermore, a second aspect of the present disclosure is preferably a wireless communication method comprising: capturing a learning image of a rainfall condition; acquiring information related to the rainfall; acquiring an amount of attenuation of transmission power due to the rainfall; creating an estimation model of the amount of attenuation of transmission power due to the rainfall based on the learning image, the information, and the amount of attenuation; capturing an image of the rainfall condition in a target environment; estimating the amount of attenuation of transmission power in the target environment based on the estimation model and the image; and implementing wireless communication control based on the estimated amount of attenuation.

[0011] Furthermore, a third aspect of the present disclosure is preferably a wireless communication device configured to perform the processes of acquiring a learning image of rainfall conditions, acquiring information related to rainfall, acquiring the amount of transmission power attenuation due to rainfall, creating an estimation model of the amount of transmission power attenuation due to rainfall based on the learning image, information, and attenuation, acquiring an image of rainfall conditions in a target environment, estimating the amount of transmission power attenuation in the target environment based on the estimation model and the image, and performing wireless communication control based on the estimated amount of attenuation.

[0012] Furthermore, a fourth aspect of the present disclosure is preferably a wireless communication program to be executed by a wireless communication device, the wireless communication program including a program for causing a computer to execute the following processes: a process for acquiring a learning image of rainfall conditions; a process for acquiring information related to rainfall; a process for acquiring the amount of transmission power attenuation due to rainfall; a process for creating an estimation model of the amount of transmission power attenuation due to rainfall based on the learning image, information, and attenuation; a process for acquiring an image of rainfall conditions in a target environment; a process for estimating the amount of transmission power attenuation in the target environment based on the estimation model and the image; and a process for implementing wireless communication control based on the estimated amount of attenuation.

[0013] According to the first to fourth aspects of the present disclosure, by estimating the amount of ultra-local attenuation due to rain attenuation, it is possible to perform wireless communication control according to the current rainfall conditions in the target environment.

[0014] FIG. 1 is a diagram showing a cover area when transmission power control is appropriate. FIG. 2 is a diagram showing a cover area when rain attenuation occurs. FIG. 3 is a diagram showing a cover area when transmission power control is performed in response to rain attenuation. FIG. 4 is a diagram showing a cover area when transmission power control is not performed again after rainfall has ended. FIG. 5 is a flowchart showing a process for creating a rain attenuation estimation model according to embodiment 1 of the present disclosure. FIG. 6 is a flowchart showing a process for estimating the amount of attenuation of transmission power according to embodiment 1 of the present disclosure. FIG. 7 is a block diagram showing the configuration of a wireless communication system that performs a series of processes according to embodiment 1 of the present disclosure continuously and fully automatically. FIG. 8 is a diagram showing the hardware configuration of a control device according to embodiment 1 of the present disclosure.

[0015] First Embodiment [Necessity of wireless communication control by base station] Prior to describing wireless communication control according to a first embodiment of the present disclosure, the necessity of wireless communication control by base station will be described. Fig. 1 is a diagram showing a coverage area when transmission power control is appropriate. Here, the coverage area of ​​two base stations is shown.

[0016] This disclosure primarily assumes wireless communication using high-frequency electromagnetic waves, such as those in the millimeter wave, terahertz, and visible bands. High-frequency electromagnetic waves have shorter propagation distances than low-frequency electromagnetic waves. Therefore, when using high-frequency electromagnetic waves, a large number of base stations must be deployed at close intervals. In other words, when using high-frequency electromagnetic waves, the impact of rain attenuation becomes significant.

[0017] In Fig. 1, transmission power control is performed appropriately so that the area 20 covered by base station 2 and the area 40 covered by base station 4 are in an appropriate state. An appropriate state is one in which the coverage areas of each base station are not separated from each other, resulting in areas that cannot be covered, or overlapping, resulting in interference between base stations. In other words, transmission power control of each base station is performed appropriately.

[0018] FIG. 2 is a diagram showing coverage areas when rain attenuation occurs. Here, the case is shown where the transmission power of base stations 2 and 4 is reduced due to rain attenuation. In this case, area 20a covered by base station 2 and area 40a covered by base station 4 become smaller than before rain attenuation occurred. As a result, area 30a, an area where wireless communication cannot be performed, appears between areas 20a and 40a. In other words, it cannot be said that the transmission power control of each base station is being performed appropriately.

[0019] FIG. 3 is a diagram showing the coverage area when transmission power control is performed against rain attenuation. Here, the case is shown where, after rain attenuation occurs as shown in FIG. 2, transmission power is increased based on the rain attenuation estimation results according to this embodiment. In this case, the area 20b covered by base station 2 and the area 40b covered by base station 4 are wider than the areas 20a and 40b, respectively, and are in an appropriate state. In other words, the transmission power control of each base station is being performed appropriately.

[0020] Fig. 4 shows the coverage area when transmission power control is not performed again after the rainfall has stopped. This shows the case where transmission power is increased as in Fig. 3 and then transmission power control is not performed again even after the rainfall has stopped.

[0021] In this case, because there is no rain attenuation, area 20c covered by base station 2 and area 40c covered by base station 4 are larger than areas 20 and 40. This results in area 30b, where areas 20c and 40c overlap. Area 30b is an area where interference between base stations can occur. In other words, it cannot be said that the transmission power control of each base station is appropriate.

[0022] As described above, in order to prevent the occurrence of areas where wireless communication cannot be performed or to reduce interference between base stations, it is necessary for base stations to appropriately control wireless communication. The present disclosure makes this possible.

[0023] [Wireless Communication Control According to First Embodiment of the Present Disclosure] Wireless communication control according to the first embodiment of the present disclosure will be described. This wireless communication control includes a process for creating a rain attenuation estimation model and a process for estimating the amount of transmission power attenuation based on the estimation model.

[0024] 5 is a flowchart showing a process for creating a rain attenuation estimation model according to the first embodiment of the present disclosure. First, in step 100, learning images of rainfall conditions are captured. The captured images are images that show at least one of the amount and descent angle of raindrops, for example.

[0025] Next, in step 102, information about rainfall is acquired. The information about rainfall includes, for example, the amount of rainfall, wind speed, size of raindrops, wind direction, rainfall intensity, etc. The information about rainfall may also include information from raincloud radar.

[0026] Next, in step 104, the amount of transmission power attenuation due to rain is obtained. This is obtained, for example, by calculation based on the conventional estimation formula shown in Non-Patent Document 1, or by actual measurement.

[0027] Next, in step 106, an estimation model of the amount of transmission power attenuation due to rain is created. This is done, for example, by machine learning based on the learning image acquired in step 100, the information acquired in step 102, and the amount of attenuation acquired in step 104.

[0028] 6 is a flowchart showing a process for estimating the amount of transmission power attenuation according to the first embodiment of the present disclosure. First, in step 110, an image of the rainfall situation in the target environment is captured. The captured image is an image that shows, for example, at least one of the amount and the angle of descent of raindrops.

[0029] Next, in step 112, the amount of transmission power attenuation in the target environment is estimated. This estimation is performed based on the estimation model created in step 106 and the image acquired in step 110. This estimation may also be performed based on rainfall observation information or rain cloud radar. In particular, when rain cloud radar information is used for estimation, the estimation may be performed based on future rain cloud radar predictions.

[0030] Next, in step 114, wireless communication control is performed based on the estimated result of the amount of attenuation. For example, a wireless communication simulation is performed based on the estimated result obtained in step 112. Then, transmission power control is performed based on the simulation result.

[0031] The above-described transmission power control may include control for optimization based on changes in the collective movement of mobile wireless terminals due to rainfall. An example of collective movement of mobile wireless terminals due to rainfall is the collective movement of mobile wireless terminals carried by pedestrians when they move en masse to a covered area. Therefore, densely populated areas, i.e., areas with a high concentration of terminals, which change with rainfall, are estimated in advance. Communication quality can be optimized by increasing the directivity of the beam from the base station toward the densely populated area.

[0032] In addition to the optimization described above, optimization based on changes in the propagation environment due to rainfall may also be performed. An example of a change in the propagation environment due to rainfall is a change in the propagation environment caused by pedestrians carrying umbrellas. Therefore, by estimating in advance the areas where pedestrians carrying umbrellas will move and adjusting the transmission power, communication quality can be optimized.

[0033] As described above, it is possible to estimate the amount of ultra-local attenuation due to rain attenuation using a method other than statistical derivation. In other words, it is possible to estimate the amount of attenuation in a target environment that is more local than conventional methods in real time. This makes it possible to control wireless communications according to the current rainfall conditions in the target environment.

[0034] [Wireless Communication System According to First Embodiment of the Present Disclosure] Fig. 7 is a block diagram showing the configuration of a wireless communication system according to the first embodiment of the present disclosure. The wireless communication system 100 includes a base station 2. The base station 2 has a control device 50. The control device 50 has an arithmetic processing unit. The control device 50 also stores programs to be executed by the arithmetic processing unit in a memory device, which will be described later. The control device 50 controls the system shown in Fig. 7 and implements the wireless communication control shown in Figs. 5 and 6 by having the arithmetic processing unit proceed with processing in accordance with the programs.

[0035] The base station 2 also has a storage device 52. The storage device 52 stores various information necessary for estimating rain attenuation. This information includes information about rainfall and images of rainfall conditions.

[0036] 7 further includes an image capturing device 54. The image capturing device 54 has a function of capturing an image of a rainfall condition in step 100 or 110. In this embodiment, rain attenuation estimation is performed by the control device 50 based on the data of the image captured by the image capturing device 54.

[0037] Specific examples of the imaging device 54 include an imaging device newly installed near the base station, a surveillance camera already installed near the base station, an in-vehicle camera, or a camera built into a smartphone used by the user.

[0038] As described above, according to the wireless communication control of this embodiment, by estimating the amount of ultra-local attenuation due to rain attenuation, wireless communication control can be performed according to the current rainfall situation in the target environment.

[0039] 7, the wireless communication method of the present embodiment can be performed as a fully automated procedure in a single operation, thereby significantly improving the efficiency of wireless communication operations according to the rainfall conditions in the target environment.

[0040] 7 is described as a system consisting of multiple devices in the first embodiment, but the present disclosure is not limited to this. That is, the configuration shown in FIG. 7 may be a single device in which the illustrated elements are housed in a single housing.

[0041] [Hardware Configuration of Control Device According to First Embodiment of the Present Disclosure] Fig. 8 is a diagram showing a hardware configuration of a control device according to the first embodiment of the present disclosure. The control device 50 includes a CPU 118. The CPU 118 is connected to a bus line 120. Memory devices such as a ROM 122, a RAM 124, and a storage 126 are connected to the bus line 120. A wireless communication program executed by the CPU 118 is stored in the memory device. The control device 50 can realize functions specific to this embodiment by the CPU 118 executing the wireless communication program.

[0042] A communication interface 128 is also connected to the bus line 120. The control device 50 communicates with a network via the communication interface 128. An operation unit 130 and a display unit 132 are also connected to the bus line 120. The operation unit 130 and the display unit 132 function as a user interface for operating the control device 50.

[0043] As described above, the control device 50 can realize the functions specific to this embodiment by the CPU 118 executing a wireless communication program. That is, the control device 50 can also be realized by a computer and the program. The program can also be recorded on a recording medium or provided via a network.

[0044] 50 Control device 54 Imaging device 100 Wireless communication system

Claims

1. A wireless communication system comprising an imaging device and a control device, wherein the imaging device is configured to perform a process of capturing learning images of rainfall conditions, and the control device is configured to perform a process of acquiring information about the rainfall, a process of acquiring an amount of transmission power attenuation due to the rainfall, and a process of creating an estimation model of the amount of transmission power attenuation due to rainfall based on the learning images, the information, and the amount of attenuation, wherein the imaging device is configured to perform a process of capturing images of rainfall conditions in a target environment, and the control device is configured to perform a process of estimating the amount of transmission power attenuation in the target environment based on the estimation model and the images, and a process of controlling wireless communication based on the estimated amount of attenuation.

2. The wireless communication system according to claim 1, wherein the learning image and the image are images in which at least one of the amount and descent angle of raindrops is known.

3. The wireless communication system according to claim 1, wherein the information relating to rainfall is information on rainfall amount, wind speed, size of raindrops, wind direction, rainfall intensity or raincloud radar.

4. The wireless communication system according to claim 1, wherein said wireless communication control includes control for optimization based on a change in collective movement of mobile wireless terminals due to rainfall.

5. The wireless communication system according to claim 1, wherein the wireless communication control includes control for optimization based on a change in the propagation environment due to rainfall.

6. A wireless communication method comprising: capturing a learning image of rainfall conditions; acquiring information related to the rainfall; acquiring an amount of transmission power attenuation due to the rainfall; creating an estimation model of the amount of transmission power attenuation due to rainfall based on the learning image, the information and the amount of attenuation; capturing an image of the rainfall conditions in a target environment; estimating the amount of transmission power attenuation in the target environment based on the estimation model and the image; and implementing wireless communication control based on the estimated amount of attenuation.

7. A wireless communication device configured to perform the following processes: acquiring a learning image of rainfall conditions; acquiring information related to the rainfall; acquiring an amount of transmission power attenuation due to the rainfall; creating an estimation model of the amount of transmission power attenuation due to rainfall based on the learning image, the information, and the amount of attenuation; acquiring an image of rainfall conditions in a target environment; estimating the amount of transmission power attenuation in the target environment based on the estimation model and the image; and performing wireless communication control based on the estimated amount of attenuation.

8. A wireless communication program to be executed by a wireless communication device, the wireless communication program including a program for causing a computer to execute the following processes: acquiring a learning image of rainfall conditions; acquiring information related to the rainfall; acquiring an amount of transmission power attenuation due to the rainfall; creating an estimation model of the amount of transmission power attenuation due to rainfall based on the learning image, the information and the amount of attenuation; acquiring an image of rainfall conditions in a target environment; estimating the amount of transmission power attenuation in the target environment based on the estimation model and the image; and implementing wireless communication control based on the estimated amount of attenuation.