Patent Publication Number: US-2022225071-A1

Title: Base station, traffic communication system, and traffic communication method

Description:
RELATED APPLICATIONS 
     The present application is a continuation based on PCT Application No. PCT/JP2020/034896, filed on Sep. 15, 2020, which claims the benefit of Japanese Patent Application No. 2019-178697 filed on Sep. 30, 2019. The content of which is incorporated by reference herein in their entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to a base station, a traffic communication system, and a traffic communication method. 
     BACKGROUND ART 
     In recent years, Intelligent Transport Systems (ITSs) have attracted attention as a technology enabling a reduction in the risk of traffic accidents. In such an intelligent transport system, roadside devices are used that correspond to base stations provided near roads. 
     Patent Literature 1 describes an apparatus that estimates a risk level indicating the probability of a traffic accident on a road section based on traffic condition indexes for the road section and that transmits, in response to determining that the estimated risk level is higher than or equal to a predetermined reference value, alert information to at least one of an in-vehicle device mounted on a vehicle located in the road section or a mobile terminal carried by a pedestrian. In this regard, the traffic condition indexes include traffic volume, traffic density, and average speed. 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: JP 2018-018214 A 
     SUMMARY 
     A base station according to a first aspect is installed around a road. The base station includes a controller and a communicator. The controller is configured to acquire weather condition information indicating a weather condition on the road, and to estimate a risk level of occurrence of a traffic accident on the road based on the weather condition information. The communicator is configured to transmit, to a vehicle on the road, a warning message including information based on the risk level estimated. 
     A traffic communication system according to a second aspect includes a vehicle and the base station according to the first aspect. 
     A traffic communication method according to a third aspect is a traffic communication method used in a base station installed around a road. The traffic communication method includes acquiring weather condition information indicating a weather condition on the road, estimating a risk level of occurrence of a traffic accident on the road based on the weather condition information, and transmitting, to a vehicle on the road, a warning message including information based on the risk level estimated. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a diagram illustrating a configuration of a traffic communication system  1  according to an embodiment. 
         FIG. 2  is a diagram illustrating a configuration of a roadside device  200  according to an embodiment. 
         FIG. 3  is a diagram illustrating a configuration of a vehicle  100  according to an embodiment. 
         FIG. 4  is a diagram illustrating operations of the roadside device  200  according to an embodiment. 
         FIG. 5  is a diagram illustrating an example of a method for estimating an insolation direction according to an embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Even the method described in Patent Literature 1 has room for improvement. 
     Thus, an object of the present disclosure is to enable provision of a safe and secure intelligent transport system. 
     A traffic communication system according to an embodiment will be described with reference to the drawings. Note that in the following description of the drawings, identical or similar components will be denoted by identical or similar reference signs. 
     Configuration of Traffic Communication System 
     First, a configuration of a traffic communication system according to an embodiment will be described.  FIG. 1  is a diagram illustrating a configuration of a traffic communication system  1  according to an embodiment. 
     As illustrated in  FIG. 1 , the traffic communication system  1  includes vehicles  100  passing through a road and roadside devices  200  used as base stations installed on a roadside corresponding to the periphery of the road. In  FIG. 1 , vehicles  100 A and  100 B are illustrated as the vehicles  100 , and roadside devices  200 A and  200 B are illustrated as the roadside devices  200 . Note that the vehicles  100  are illustrated as an automobile such as an ordinary automobile and a light automobile, but may be any vehicle passing through a road, for example, a two-wheel motor vehicle (motorcycle) or the like. 
     An in-vehicle device  150  performing wireless communication is mounted on each of the vehicles  100 . The in-vehicle device  150  performs roadside-to-vehicle communication with the roadside devices  200 . 
     The roadside devices  200  are installed around the road. The roadside devices  200  may be installed at intersections on an ordinary road, or on the roadside of an expressway, but a case will hereinafter mainly be described in which the roadside devices  200  are installed around intersections. Note that the roadside devices  200  may be installed around a road at locations different from the intersections. 
     In the example illustrated in  FIG. 1 , the roadside device  200 A is installed on a traffic light (traffic signal light)  300  or a pole of the traffic light and operates in conjunction with the traffic light  300 . For example, the roadside device  200 A transmits, to the vehicle  100  (in-vehicle device  150 ), a radio signal including signal information related to the traffic light  300 . 
     For such roadside-to-vehicle communication, wireless communication may be used that is based on broadcasting for a large number of unspecified destinations. Alternatively, the roadside-to-vehicle communication may use wireless communication that is based on multicast for a large number of specified destinations, or unicast wireless communication for a single specified destination. 
     Each roadside device  200  is connected to a central apparatus  400  via a communication line. The central apparatus  400  manages road features such as the position of a road, the height above sea level of the road, the gradient of the road. 
     Configuration of Roadside Device 
     Now, a configuration of the roadside device  200  according to an embodiment will be described.  FIG. 2  is a diagram illustrating a configuration of the roadside device  200  according to an embodiment. 
     As illustrated in  FIG. 2 , the roadside device  200  includes a communicator  21 , a controller  22 , and an interface  23 . 
     The communicator  21  includes an antenna  21   a , a receiver  21   b , and a transmitter  21   c , and performs wireless communication via the antenna  21   a . The communicator  21  performs roadside-to-vehicle communication with the vehicle  100  (in-vehicle device  150 ). As described above, the roadside-to-vehicle communication may be performed by unicast, broadcast, or multicast. 
     The antenna  21   a  may be a non-directional antenna, or may be a directional antenna having directivity. The antenna  21   a  may be an adaptive array antenna that can dynamically change its directivity. 
     The communicator  21  includes a receiver  21   b  that converts a radio signal received by the antenna  21   a  into receive data and outputs the receive data to the controller  22 . Additionally, the communicator  21  includes a transmitter  21   c  that converts the receive data output by the controller  22  into a radio signal and transmits the radio signal from the antenna  21   a.    
     The wireless communication scheme of the communicator  21  may be a scheme conforming to the T109 standard of the Association of Radio Industries and Businesses (ARIB), a scheme conforming to the Vehicle-to-everything (V2X) standard of the Third Generation Partnership Project (3GPP), and/or a scheme conforming to a wireless Local Area Network (LAN) standard such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 series. The communicator  21  may be configured to be capable of conforming to all of these communication standards. 
     The controller  22  controls various functions of the roadside device  200 . The controller  22  includes at least one memory  22   b  and at least one processor  22   a  electrically connected to the memory  22   b . The memory  22   b  includes a volatile memory and a non-volatile memory and stores information used for processing in the processor  22   a  and programs executed by the processor  22   a . The processor  22   a  executes the programs stored in the memory  22   b  to perform various processing operations. 
     The interface  23  is connected to a sensor  500  in a wired or wireless manner. The sensor  500  detects a mobile body on the road, in particular a pedestrian. In an embodiment, the sensor  500  includes a plurality of sensors. Each of the sensors may be any sensor as long as the sensor can sense a mobile body on a road, and may be at least one of an image sensor (roadside camera), a millimeter wave sensor, an ultrasound sensor, or an infrared sensor. 
     For example, each of the sensors is a roadside camera installed on the roadside.  FIG. 2  illustrates an example in which the sensor  500  includes a plurality of roadside cameras (visible light camera  500   a  and infrared camera  500   b ). The roadside camera captures an image of a road. The roadside camera outputs the captured image to the controller  22  via the interface  23 . 
       FIG. 2  illustrates an example in which the roadside camera is configured separately from the roadside device  200 . However, the roadside camera may be configured integrally with the roadside device  200 . 
     The roadside camera may include a visible light camera  500   a  and an infrared camera  500   b . The roadside camera may include only a visible light camera  500   a . An infrared camera is a camera that captures infrared light radiated from an object to be imaged. A known infrared camera is adopted for the infrared camera  500   b.    
     The interface  23  may be connected to a weather sensor  700 . The weather sensor  700  may be any sensor for sensing weather conditions. For example, the weather sensor  700  includes at least one of an insolation sensor, a rain sensor, a fog sensor, or an air pollution sensor. Insolation sensors for respective directions may be provided. 
     Additionally, the interface  23  may be connected to the central apparatus  400 . Furthermore, the interface  23  may be connected to the Internet. 
     In the roadside device  200  configured as described above, the controller  22  acquires weather condition information indicating weather conditions on the road by using the weather sensor  700 . The controller  22  may acquire the weather condition information by means other than the weather sensor  700 . The controller  22  estimates the risk level of occurrence of a traffic accident on the road at least based on the weather condition information. In this regard, in order to estimate the risk level, the controller  22  may acquire other information for estimating the risk level (vehicle movement direction information, intersection information, pedestrian information, and/or the like described below). In this case, the controller  22  may estimate the risk level based on the weather condition information and the other information. Then, the communicator  21  transmits a warning message including information based on the estimated risk level in step S 13 . 
     As described above, by estimating the risk level of occurrence of a traffic accident on the road based on the weather condition information, the estimation accuracy of the probability (risk level) of a traffic accident can be enhanced. 
     Configuration of Vehicle 
     Now, a configuration of the vehicle  100  according to an embodiment will be described.  FIG. 3  is a diagram illustrating a configuration of the vehicle  100  according to an embodiment. 
     As illustrated in  FIG. 3 , the vehicle  100  includes a communicator  11 , a Global Navigation Satellite System (GNSS) receiver  12 , a notifier  13 , at least one camera  14 , a drive controller  15 , and a controller  16 . 
     The communicator  11  includes an antenna  11   a , a receiver  11   b , and a transmitter  11   c , and performs wireless communication via the antenna  11   a . The communicator  11  performs roadside-to-vehicle communication with the roadside device  200 . As described above, the roadside-to-vehicle communication may be performed by unicast, broadcast, or multicast. 
     The communicator  11  includes the receiver  11   b  that converts a radio signal received by the antenna  11   a  into receive data and outputs the receive data to the controller  16 . Additionally, the communicator  11  includes the transmitter  11   c  that converts transmit data output by the controller  16  into a radio signal and transmits the radio signal from the antenna  11   a.    
     The radio communication scheme of the communicator  11  may be a scheme conforming to the T109 standard of the ARIB, a scheme conforming to the V2X standard of the 3GPP, and/or a scheme conforming to a wireless LAN standard such as the IEEE 802.11 series. The communicator  11  may be configured to be capable of conforming to all of these communication standards. 
     The GNSS receiver  12  performs positioning based on GNSS satellite signals, and outputs, to the controller  16 , GNSS position information indicating the current geographical position (latitude and longitude) of the vehicle  100 . 
     Under the control of the controller  16 , the notifier  13  notifies the driver of the vehicle  100  of information. The notifier  13  includes a display  13   a  that displays information, and a speaker  13   b  that auditorily outputs information. 
     The camera  14  is a camera mounted on the vehicle  100 . The camera  14  may include a front camera that captures an image of the front of the vehicle. The camera  14  outputs the captured image to the controller  16 . The vehicle  100  need not include the camera  14 . 
     The drive controller  15  controls an engine or a motor as a source of power, a power transmission mechanism, brakes, and the like. In a case where the vehicle  100  is a self-driving vehicle, the drive controller  15  may control drive of the vehicle  100  in cooperation with the controller  16 . 
     The controller  16  controls various functions of the vehicle  100  (in-vehicle device  150 ). The controller  16  includes at least one memory  16   b  and at least one processor  16   a  electrically connected to the memory  16   b . The memory  16   b  includes a volatile memory and a non-volatile memory and stores information used for processing in the processor  16   a  and programs executed by the processor  16   a . The processor  16   a  executes the programs stored in the memory  16   b  to perform various processing operations. 
     In the vehicle  100  configured in this manner, in response to the communicator  11  receiving a warning message from the roadside device  200 , based on the warning message, the controller  16  may perform self-driving control (e.g., deceleration) of the vehicle  100  or may provide notification to the driver. 
     The probability (risk level) of a traffic accident also varies depending on the weather conditions as well as the traffic volume, traffic density, and average speed. For example, even with a low traffic volume, a low traffic density, and a low average speed, the probability of a traffic accident is considered to be high in a case where the evening sun is shining or when there is a fog. Accordingly, the known art has room for improvement in an enhancement of the estimated accuracy of the probability of a traffic accident. 
     Operations of Roadside Device 
     Operations of the roadside device  200  according to an embodiment will now be described.  FIG. 4  is a diagram illustrating operations of the roadside device  200  according to an embodiment. 
     1. Step S 11   
     As illustrated in  FIG. 4 , in step S 11 , the controller  22  acquires weather condition information indicating the weather conditions on the road. The weather condition information may include weather phenomenon information indicating the condition of the weather phenomenon on the road and insolation direction information indicating the direction of insolation to the vehicle on the road (hereinafter simply referred to as “insolation direction”). 
     1.1. Acquisition of Weather Phenomenon Information 
     The weather phenomenon includes rain, fog, air pollution, and the like. The air pollution includes photochemical smog, microparticulate matter (so-called PM2.5), and the like. The weather phenomenon information may include fog information indicating the fog density, rain information indicating the amount of rainfall, and air pollutant information indicating the concentration of air pollutants. The controller  22  may acquire the weather phenomenon information from the weather sensor  700 . The controller  22  may acquire the weather phenomenon information via the Internet. The controller  22  may recognize the weather phenomenon by using the image recognition method based on the captured image obtained by the roadside camera, acquiring the weather phenomenon information. 
     1.2. Acquisition of Insolation Direction Information 
     The controller  22  may identify the insolation direction by using the insolation sensor, or may estimate the insolation direction by using insolation direction estimation information without using the insolation sensor. In the former case, the controller  22  acquires insolation direction information from the insolation sensor. In the latter case, the controller  22  acquires, as insolation direction information, information indicating the estimated insolation direction. 
     The insolation direction estimation information includes information indicating the current time, and road position information indicating the position of the road (e.g., the longitude and latitude of the representative point on the road). The controller  22  may acquire information indicating the current time from the clock provided in the roadside device  200 , or may acquire, via the Internet, information indicating the current time. The controller  22  may acquire road position information from the central apparatus  400 , or may acquire road position information stored in the memory  22   b  when the roadside device  200  is initially installed. 
       FIG. 5  is a diagram illustrating an example of a method for estimating the insolation direction based on insolation direction estimation information according to an embodiment. As illustrated in  FIG. 5 , the controller  22  identifies the position of the road (the longitude and latitude of the representative point A on the road) from the road position information acquired, identifies the current time (M minutes past H o&#39;clock on Dth day of month M in year Y) from the clock, and applies a known calculation method to identify the altitude h and the azimuthal angle α of the sun corresponding to the road position (representative point A). Then, the controller  22  determines the direction identified by the altitude h and the azimuthal angle α of the sun (the direction indicated by a straight line drawn from the sun B to the representative point A in  FIG. 5 ) to be the direction of insolation. 
     The insolation direction estimation information may further include information indicating the height above sea level of the road and information indicating the gradient of the road. The controller  22  may correct, based on the height above sea level and the gradient of the road, the direction identified by the altitude and the azimuthal angle of the sun corresponding to the position of the road, and identify the corrected direction as the direction of insolation. This allows identification of a more accurate direction of insolation. The information indicating the height above sea level of the road and information indicating the gradient of the road may be pre-stored in the memory  22   b  when the roadside device  200  is initially installed. The controller  22  may acquire, from the central apparatus  400 , information indicating the height above sea level of the road and information indicating the gradient of the road. 
     2. Step S 12   
     In step S 12 , the controller  22  acquires other information for estimating the risk level (vehicle movement direction information, intersection information, pedestrian information, and the like described below). 
     The vehicle movement direction information is information indicating the movement direction of the vehicle  100 . The controller  22  identifies the movement direction of the vehicle  100  by using the communicator  21  to receive a notification message from the vehicle  100 . The notification message may include information indicating the movement direction of the vehicle  100 , or may include information indicating the position (longitude and latitude) of the vehicle  100 . The controller  22  may identify the movement direction of the vehicle  100  by periodically receiving information indicating the position (longitude and latitude) of the vehicle  100 . Additionally, the controller  22  may identify the movement direction of the vehicle  100  without using the notification message. For example, in a case where the road is for one-way traffic, the direction faced by the road may be identified as the movement direction of the vehicle  100  on the road. 
     The controller  22  acquires intersection information indicating whether the roadside device  200  is installed around an intersection. The intersection information may be pre-stored in the memory  22   b  when the roadside device  200  is initially installed. The controller  22  may acquire intersection information from the central apparatus  400 . 
     The controller  22  acquires the captured image acquired by the sensor  500 , and acquires pedestrian information from the captured image. The pedestrian information includes information indicating the number of pedestrians, information indicating whether the pedestrians include any child or elderly person, and information indicating whether the pedestrians include a person operating a mobile device (such as a smartphone). For example, the controller  22  can extract at least one of a characteristic contour, a characteristic color, or a characteristic luminance of an object to be imaged based on the captured image obtained by the roadside camera, and identify the object to be imaged based on the extracted information. As this identification technique, any known technique may be used. According to such an identification technique, the controller  22  identifies pedestrians from the captured image, determines the number of identified pedestrians, determines whether any of the pedestrians is a child or an elderly person, and determines whether any of the pedestrians is operating a mobile device. Then, the controller  22  acquires, by such identification and determination processing, information indicating the number of pedestrians, information indicating whether the pedestrians include any child or elderly person, and information indicating whether the pedestrians include a person operating a mobile device. 
     Basically, the controller  22  acquires pedestrian information from the captured image obtained by the visible light camera  500   a , but may select the infrared camera  500   b  between the visible light camera  500   a  and the infrared camera  500   b  based on the weather condition information, and may acquire the pedestrian information from the captured image obtained by the infrared camera  500   b . For example, in a case where the fog density is higher than or equal to a predetermined value, the infrared camera  500   b  is selected. In this regard, the “fog density” may be interpreted as any one of the “amount of rainfall” or the “concentration of air pollutants”. With the fog density increased, visible light from the object to be imaged is blocked by the fog, and a reduced amount of visible light can enter the visible light camera  500   a , degrading the quality of the captured image obtained by the visible light camera  500   a . This may prevent the pedestrians from being identified. On the other hand, infrared light has a high permeability with respect to the fog and the like, and thus even with the fog density increased, the image quality of the captured image obtained by the infrared camera  500   b  is prevented from being degraded, allowing the pedestrians to be identified. Furthermore, the mobile device generates heat during operation, and thus when whether the pedestrians include a person operating a mobile device is determined, a more accurate determination can be made by using the captured image obtained by the infrared camera  500   b.    
     The controller  22  may acquire pedestrian information by image recognition based on both the captured image obtained by the visible light camera  500   a  and the captured image obtained by the infrared camera  500   b.    
     3. Step S 13   
     In step S 13 , the controller  22  estimates the risk level of occurrence of a traffic accident on the road based on each item identified by the weather condition information, vehicle movement direction information, intersection information, and pedestrian information. Such items include the fog density, the concentration of air pollutants, the amount of rainfall, the relationship between the insolation direction and the vehicle movement direction, whether the roadside device  200  is installed around the intersection, the number of pedestrians, whether the pedestrians include a child or an elderly person, and whether the pedestrians include a person operating a mobile device. 
     In a case where information of a plurality of items is available, the controller  22  may estimate item-by-item risk levels, and estimate the overall risk level based on the risk levels for the respective items. The risk level may be a value. A larger value may indicate a higher risk level, and a smaller value may indicate a lower risk level. 
     3.1. Method for Estimating Risk Level for Each Item 
     For example, the controller  22  estimates a value for the risk level as follows. 
     The controller  22  estimates a large value for the risk level depending on the insolation direction. 
     The controller  22  associates the fog density with the risk level, and a larger value for the risk level is estimated for a higher fog density. 
     The controller  22  associates the concentration of air pollutants with the risk level, and a larger value for the risk level is estimated for a higher concentration of air pollutants. 
     The controller  22  associates the amount of rainfall with the risk level, and a larger value for the risk level is estimated for a larger amount of rainfall. 
     The controller  22  estimates a larger value for the risk level for a case where the movement direction of the vehicle  100  and the direction of insolation are opposite to each other than for a case where the movement direction of the vehicle  100  and the direction of insolation are not opposite to each other. In a case where the movement direction of the vehicle  100  and the direction of insolation are opposite to each other, the eyes of the driver of the vehicle  100  are exposed to sunlight through the windshield of the vehicle  100 , and thus an obstacle, a mobile body, or the like on the road may be invisible to the driver. Accordingly, a larger value for the risk level is estimated for a case where the movement direction of the vehicle  100  and the direction of insolation are opposite to each other than for a case where the movement direction of the vehicle  100  and the direction of insolation are not opposite to each other. In this regard, a first risk level refers to the risk level estimated for a case where the movement direction of the vehicle and the direction of insolation are not opposite to each other, and a second risk level higher than the first risk level refers to the risk level estimated for a case where the movement direction of the vehicle and the direction of insolation are opposite to each other. 
     The controller  22  estimates a larger value for the risk level for a case where the roadside device  200  is installed around the intersection than for a case where the roadside device  200  is not installed around the intersection. In this regard, a third risk level refers to the risk level estimated for a case where the roadside device  200  is not installed around the intersection, and a fourth risk level higher than the third risk level refers to the risk level estimated for a case where the roadside device  200  is installed around the intersection. 
     The controller  22  estimates a larger value for the risk level for a larger number of pedestrians. 
     The controller  22  estimates a larger value for the risk level for a case where the pedestrians include a child or an elderly person than for case where the pedestrians include no child or elderly person. 
     The controller  22  estimates a larger value for the risk level for a case where the pedestrians include a person operating a mobile device than for a case where the pedestrians include no person operating a mobile device. 
     3.2. Method for Estimating Overall Risk Level 
     The controller  22  estimates the overall risk level based on the risk levels for the respective items described above. 
     The controller  22  may estimate the overall risk level by adding the risk levels for the respective items together. The controller  22  may estimate the overall risk level by weighting the item-by-item risk levels and adding the weighted risk levels together. 
     4. Step S 14   
     In step S 14 , the communicator  21  transmits a warning message including information based on the risk level estimated in step S 13 . 
     The warning message may include a numerical value indicating the estimated risk level itself. The warning message may also include information calling for attention which information is generated based on the estimated risk level. 
     The communicator  21  may determine whether to transmit the warning message based on the result of a comparison between the estimated risk level and a threshold. For example, the communicator  21  may determine not to transmit the warning message in a case where the estimated risk level is lower than or equal to the threshold. This allows frequent issuance of the warning message with low risk level to be avoided. 
     Also, the warning message need not necessarily mean a message notified in order to raise alert but may be used as a message for notifying information as needed. 
     The communicator  21  transmits the warning message to the vehicle  100  by unicast, broadcast, or multicast. 
     In response to estimation of an item-by-item risk level corresponding to the direction of insolation during estimation of the risk level, the communicator  21  may transmit the warning message to the vehicle  100  corresponding to the movement direction of the vehicle  100  used in estimating the item-by-item risk level. For example, the notification message identifying the movement direction of the vehicle includes information identifying the transmission source of the notification message, and the communicator  21  transmits the warning message to a destination corresponding to the transmission source identified based on the notification message. 
     In response to the warning message received, the in-vehicle device  150  may perform self-driving control (e.g., deceleration or stoppage) of the vehicle  100 , or may provide notification to the driver. 
     The in-vehicle device  150  may control the speed of the vehicle  100  in accordance with the warning message received. The in-vehicle device  150  may change the speed according to the value of the risk level in the warning message. For example, the speed corresponding to the value of the risk level is predetermined, and the in-vehicle device  150  provides control via the drive controller  15  such that the speed corresponds to the value of the risk level. Before the roadside device  200  transmits the warning message, the roadside device  200  may include, in the warning message, the speed information corresponding to the value of the risk level, and in response to receiving the warning message, the in-vehicle device  150  may change the speed in accordance with the speed information included in the warning message. In such a configuration, the speed of the vehicle  100  is controlled in accordance with the risk level sensed by the roadside device  200 , and thus a safe and secure intelligent transport system can be provided. 
     OTHER EMBODIMENTS 
     A program may be provided that causes a computer to execute each of the processing operations performed by the in-vehicle device  150  or the roadside device  200 . The program may be recorded in a computer-readable medium. Use of the computer-readable medium enables the program to be installed on a computer. Here, the computer-readable medium on which the program is recorded may be a non-transitory recording medium. The non-transitory recording medium is not particularly limited and may be, for example, a recording medium such as a CD-ROM or a DVD-ROM. 
     In addition, circuits for executing the processing to be performed by the in-vehicle device  150  or the roadside device  200  may be integrated, and at least part of the in-vehicle device  150  or the roadside device  200  may be configured as a semiconductor integrated circuit (a chipset or an SoC). 
     Embodiments have been described above in detail with reference to the drawings, but specific configurations are not limited to those described above, and various design modifications can be made without departing from the gist of the present disclosure.