JP2007110401A - Dsrc system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a DSRC system wherein a user can recognize a state of a wireless communication function of an in-vehicle unit without the need for using an exclusive checker for checking the wireless communication state of the in-vehicle unit. <P>SOLUTION: An on-road apparatus informs the in-vehicle unit 1 of the user about an average communication time calculated by communication with a plurality of in-vehicle unites, the in-vehicle unit 1 calculates a communication time at the communication with the on-road apparatus, calculates an error in the calculated communication time on the basis of the calculated communication time and the average communication time notified by the on-road apparatus, diagnoses the wireless communication function of a communication circuit 3 and an antenna 2 of the in-vehicle unit 1 on the basis of the error, and informs the user about a result of the diagnosis. Thus, the user can recognize the state of the wireless communication function of the in-vehicle unit 1 without the need for using the exclusive checker by an installation agent of the in-vehicle unit 1 and obtain the state of the wireless communication function in a real environment. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a DSRC (Dedicated Short-Range Communication) system used in an ETC (Electronic Toll Collection) system of an ITS (Intelligent Transport System), in particular, an in-vehicle device. It is related with the DSRC system which diagnoses the radio | wireless communication function of onboard equipment using road-to-vehicle communication in the state attached to the vehicle.

In recent years, services using DSRC have begun to spread. For example, an ETC system has already been put into practical use. The number of ETC on-board units has exceeded 7 million in June 2005. In addition to ETC systems, parking lots, gas stations, drive-through payment services, etc. are being put into practical use, and in-vehicle devices that use DSRC services are expected to spread in the future. Therefore, it is important to ensure the reliability of road-to-vehicle communication.
In general, the vehicle-mounted device has a self-diagnosis function, and is configured to be able to inspect functions inside the vehicle-mounted device such as an IC card reading function and a wireless communication unit when the power is turned on.
Moreover, the state of the wireless communication function in the vehicle-mounted device after being connected to the vehicle can be checked with a dedicated checker (see, for example, Patent Document 1).

JP 2001-223650 A (pages 3 to 5, FIG. 1)

However, in the conventional OBE, although the state inside the OBE can be self-diagnosed, whether the wireless communication function of the OBE is actually communicable with the road device with the OBE attached to the vehicle. There was a problem that it could not be diagnosed.
Further, the above-described dedicated checker is expensive to be purchased by a general user, and usually only an on-board device installation contractor or dealer is owned. Therefore, general users themselves have not inspected the wireless communication function of the vehicle-mounted device using the dedicated checker.

Further, the above-described dedicated checker cannot simulate road-to-vehicle communication during actual travel. This is because the road equipment installed on the road has a region where the radio wave environment is bad due to the surrounding buildings and the like. The radio wave environment varies depending on the roadside device.
As an example of the distribution of the electric field strength of the road equipment, the region where the electric field strength is -55 dBm to -60 dBm is 16 m from the road equipment side, and the region where the electric field strength is -60 dBm to -65 dBm is 25 m from the road equipment side. In addition, it is assumed that the region where the electric field intensity is −65 dBm to −70 dBm is 36 m from the roadside device side. On the other hand, the traveling speed of the vehicle is, for example, 20 km / h.
In this case, when the vehicle equipped with the vehicle-mounted device travels at a speed of 20 km / h under the road unit having the electric field strength distribution described above, the electric field strength travels in a region where the electric field strength is -55 dBm to -60 dBm. The possible time is about 2.9 seconds. The time during which the electric field intensity can travel in the region where the electric field intensity is from −60 dBm to −65 dBm is about 4.5 seconds. The time during which the electric field intensity can travel in the region of −65 dBm to −70 dBm is about 6.5 seconds.
Here, when the input sensitivity of the vehicle-mounted device is −63 dBm, the time during which roads and vehicles can be connected is about 4.5 seconds. However, if the input sensitivity of the vehicle-mounted device deteriorates and becomes, for example, -59 dBm, in this case, the time that can be connected between the road and the vehicle is shortened to about 2.9 seconds.

In general, the input sensitivity of the vehicle-mounted device is inspected before shipment from the factory, but the vehicle-mounted device is not inspected by attaching the vehicle-mounted device to the vehicle and communicating with the road equipment actually operated.
Further, even when the wireless communication function of the in-vehicle device is deteriorated as described above, the above-described dedicated checker can be used for the wireless communication of the in-vehicle device as long as wireless communication can be performed between the on-vehicle device and the above-described dedicated checker. The function is judged as normal. That is, even if there is no abnormality in the wireless communication function of the vehicle-mounted device with the dedicated checker, there is a possibility that communication with the actual roadside device may fail.

 This invention is made in order to solve the above problems, and the user can know the state of the wireless communication function of the vehicle-mounted device without using a dedicated checker for checking the wireless communication function of the vehicle-mounted device. The aim is to obtain a DSRC system that can be used.

In the DSRC system according to the present invention, in the DSRC system for exchanging information by DSRC communication between the on-road device installed on the road and the vehicle-mounted device mounted on the vehicle,
The road device notifies the vehicle-mounted device of a reference value of a predetermined physical quantity required for communication,
The in-vehicle device is a wireless communication means for performing communication, calculates a predetermined physical quantity required for communication, and calculates the predetermined physical quantity calculated based on the calculated physical quantity and a reference value of the predetermined physical quantity notified from the road unit Calculating means for calculating an error of the physical quantity, diagnostic means for diagnosing the state of the wireless communication means based on the error calculated by the calculating means, and notification for notifying the user of the state of the wireless communication means diagnosed by the diagnostic means Means are provided.

As described above, the present invention, in the DSRC system for exchanging information by DSRC communication between the on-road device installed on the road and the on-vehicle device mounted on the vehicle,
The road device notifies the vehicle-mounted device of a reference value of a predetermined physical quantity required for communication,
The in-vehicle device is a wireless communication means for performing communication, calculates a predetermined physical quantity required for communication, and calculates the predetermined physical quantity calculated based on the calculated physical quantity and a reference value of the predetermined physical quantity notified from the road unit Calculating means for calculating an error of the physical quantity, diagnostic means for diagnosing the state of the wireless communication means based on the error calculated by the calculating means, and notification for notifying the user of the state of the wireless communication means diagnosed by the diagnostic means Since the means is provided, the user can know the state of the wireless communication means of the vehicle-mounted device without using the dedicated checker of the vehicle-mounted device installation supplier, and can obtain the state of the wireless communication means in the actual environment. .

Embodiment 1 FIG.
The first embodiment will be described below with reference to the drawings.
FIG. 1 is a block diagram showing a DSRC on-vehicle device according to Embodiment 1 of the present invention.
In FIG. 1, a DSRC on-vehicle device (hereinafter also simply referred to as “on-vehicle device”) 1 includes an antenna 2, a communication circuit 3 that performs DSRC communication via the antenna 2, a CPU 4, an EEPROM 5 that is a nonvolatile memory, and a human interface. Are connected to the vehicle-side power supply 11, connected to the power supply circuit 10 for supplying power to the DSRC in-vehicle device 1, connected to the external device I / F 12 connected to the external device 13, and connected to the IC card 16. The IC card I / F 15 and a security application module (SAM) 14 are arranged between the IC card I / F 15 and the CPU 4 and perform security management.
The antenna 2 and the communication circuit 3 constitute a wireless communication unit.
The HMI function 6 includes operation means 7 such as a volume change button and a wireless communication function diagnosis result request button, sound output means 8 such as a speaker, and light output means 9 such as an LED. The power supply circuit 10 is connected to the vehicle-side power supply 11, and the external device I / F 12 is connected to an external device 13 such as a car navigation system. The IC card I / F 15 is connected to the IC card 16.
The CPU 4 is connected to the communication circuit 3, the EEPROM 5, the HMI function 6, the power supply circuit 10, the external device I / F 12, and the SAM 14, and controls the operation of the DSRC on-vehicle device. The CPU 4 includes a calculation function (calculation means) for calculating a communication time A (a predetermined physical quantity required for communication) from communication connection to disconnection between the vehicle-mounted device 1 and the roadside device. In addition, the CPU 4 calculates a communication time error amount C (calculation means) that is an error between the communication time A and the average communication time B (reference value of a predetermined physical quantity required for communication) received from the roadside device. Is provided. Further, a diagnostic function (diagnostic means) for diagnosing the state of the wireless communication function of the vehicle-mounted device 1 based on the communication time error amount C is provided. Furthermore, a notification function (notification means) for notifying the state of the wireless communication function (wireless communication means) of the vehicle-mounted device 1 diagnosed by the diagnosis function using the HMI function 6 or the external device 13 is provided.

FIG. 2 is a flowchart showing a procedure when the on-board DSRC device according to Embodiment 1 of the present invention diagnoses the wireless communication function.
Next, the operation of the DSRC in-vehicle device according to the first embodiment will be described with reference to FIG.
Assume that in a vehicle equipped with the DSRC on-vehicle device 1, the vehicle enters the DSRC communication area with the roadside device in a state where power is supplied from the vehicle-side power source 11 to the power circuit 10 of the DSRC on-vehicle device 1. The vehicle-mounted device 1 starts measuring the communication time A (step S102) immediately after the communication connection with the roadside device (step S101). After the communication connection between the road vehicles, the road device transmits an average communication time B that is a value indicating a predetermined communication time to the vehicle-mounted device 1. The average communication time B is “an average value from communication connection to communication disconnection obtained from a plurality of vehicle-mounted devices that have passed through the road device”. The on-vehicle device 1 receives the average communication time B (step S103).

  The vehicle-mounted device 1 ends the measurement of the communication time A together with the end of communication (step S104) (step S105). After the end of communication, the vehicle-mounted device 1 obtains a communication time error amount C with respect to the communication time A measured by the vehicle-mounted device with reference to the average communication time B received from the road device (step S106). The wireless communication function of the vehicle-mounted device 1 can be determined by the communication time error amount C obtained, for example, because it is possible to determine that the communicable area between the vehicle-mounted device 1 and the road device has decreased due to a decrease in the reception sensitivity of the vehicle-mounted device 1. Can be diagnosed. When the communication time error amount C exceeds the allowable range (step S107), the sound output means 8 for outputting a sound, a buzzer, light, etc. and the light output as a diagnosis result that there is an abnormality in the wireless communication function of the vehicle-mounted device 1 The user is notified using the HMI function 6 such as means 9 (step S108).

As described above, according to the first embodiment, the vehicle-mounted device has the function of calculating the communication time A, and the wireless communication function of the vehicle-mounted device is determined from the communication time error amount C with the average communication time B notified from the road unit. Since the diagnosis is made, the user can know the state of the wireless communication function of the vehicle-mounted device without using the dedicated checker of the vehicle-mounted device installation supplier.
In addition, since the wireless communication function is diagnosed in an actual environment, it is possible to obtain a diagnosis result with higher reliability than that of the dedicated checker, and to prevent communication failure caused by deterioration of the wireless communication function. it can.

Embodiment 2. FIG.
The first embodiment considers the communication from the start of communication to disconnection as a communicable region between roads and vehicles, and is configured to diagnose the wireless communication function of the on-vehicle device based on the communication time A measured by the on-vehicle device. Is extremely fast (or slow), the communication time A measured by the vehicle-mounted device is remarkably short (or long), and accurate diagnosis may not be performed. For this reason, the second embodiment is configured so that the radio communication function can be diagnosed regardless of the speed of the vehicle.
The second embodiment will be described below with reference to the drawings.
The configuration of the DSRC in-vehicle device of the second embodiment is the same as that in FIG. However, in the second embodiment, the CPU 4 calculates the sum E (predetermined physical quantity required for communication) of the data amount received from the roadside device between the on-vehicle device 1 and the roadside device from the communication connection to the disconnection. An error is calculated between the sum E of the received data amounts and a value D (a reference value of a predetermined physical quantity required for communication) indicating a predetermined data amount which is separately transmitted from the road device and transmitted by the road device. And an arithmetic function (calculation means) for calculating the error amount F. Further, a diagnostic function (diagnostic means) for diagnosing the state of the wireless communication function of the vehicle-mounted device 1 based on the error amount F is provided. Furthermore, a notification function (notification means) for notifying the state of the wireless communication function (wireless communication means) of the vehicle-mounted device 1 diagnosed by the diagnosis function using the HMI function 6 or the external device 13 is provided.

FIG. 3 is a flowchart showing a procedure when the on-board DSRC device according to Embodiment 2 of the present invention diagnoses a wireless communication function.
Next, the operation of the DSRC vehicle-mounted device according to the second embodiment will be described with reference to FIG.
Assume that in a vehicle equipped with the DSRC on-vehicle device 1, the vehicle enters the DSRC communication area with the roadside device in a state where power is supplied from the vehicle-side power source 11 to the power circuit 10 of the DSRC on-vehicle device 1. After the communication connection between the road vehicles (step S201), the road device transmits a value D indicating a predetermined data amount to the vehicle-mounted device 1. Here, the value D indicating the predetermined data amount is “the total data amount that the main road device transmits to the vehicle-mounted device when the communication is good and the retransmission is not performed within the communication area of the main road device. It is the value shown.

When the on-vehicle device 1 receives a value D indicating a predetermined amount of data from the road device (step S202), thereafter, the vehicle-mounted device 1 calculates the sum E of the amount of data received from the road device until communication disconnection (step S203). At the end of communication (step S204), the vehicle-mounted device ends the calculation of the sum E of the amount of data received from the roadside device (step S205).
The vehicle-mounted device calculates an error amount F with respect to the sum E of the received data amounts with reference to the value D indicating the predetermined data amount (step S206). From the error amount F of the received data amount, for example, it can be determined that the sum E of the received data amount has increased because the roadside device has retransmitted due to a decrease in the transmission output of the on-vehicle device 1. The communication function can be diagnosed. If the error amount F of the received data amount exceeds the allowable range (step S207), the on-vehicle device 1 outputs a sound, buzzer, light, etc. as a diagnosis result that there is an abnormality in the communication function of the on-vehicle device 1 The user is notified using the HMI function 6 such as the output means 8 and the light output means 9 (step S208).

  As described above, according to the second embodiment, the vehicle-mounted device has the function of calculating the sum E of the received data from the road unit, and the error amount F from the value D indicating the predetermined data amount notified from the road unit. Therefore, the wireless communication function of the vehicle-mounted device can be diagnosed in the actual environment regardless of the vehicle speed.

Embodiment 3 FIG.
In the second embodiment, the vehicle-mounted device has a function of calculating the sum E of received data from the road device, and the wireless communication of the vehicle-mounted device from the error amount F with the value D indicating the predetermined data amount notified from the road device. Although it is configured to diagnose the function, multiple applications may be executed from communication connection to disconnection. In this case, when the road device starts communication, “communication is good within the communication area of this road device. When the retransmission is not performed, the value indicating the total amount of data transmitted from the road unit to the vehicle-mounted device cannot be clarified, and therefore an accurate diagnosis cannot be performed. For this reason, the third embodiment enables diagnosis of the wireless communication function even when a plurality of applications are executed on the same road device.
The third embodiment will be described below with reference to the drawings.
The configuration of the DSRC in-vehicle device of Embodiment 3 is the same as that in FIG. However, in the third embodiment, the calculation function of the CPU 4 calculates the communication time (a predetermined physical quantity required for communication) per application, and thereby the average communication time per application notified from the roadside device. An error amount with respect to (a reference value of a predetermined physical quantity required for communication) is calculated, and the state of the wireless communication function is diagnosed and notified.

FIG. 4 is a flowchart showing a procedure when the on-board DSRC device according to Embodiment 3 of the present invention diagnoses the wireless communication function.
Next, the operation of the DSRC vehicle-mounted device according to Embodiment 3 will be described with reference to FIG.
In a vehicle equipped with the DSRC on-vehicle device 1, it is assumed that the vehicle has entered the DSRC communication area with the on-road unit in a state where power is supplied from the vehicle-side power source 11 to the power circuit 10 of the DSRC on-vehicle device 1. Are connected for communication (step S301). After the communication connection, the road device transmits an application start notification to the vehicle-mounted device 1, and the application is started when the vehicle-mounted device 1 receives the application start notification (step S302). The in-vehicle device 1 starts measuring the application communication time G along with the reception of the application start notification (step S303). The road device transmits a value H indicating a predetermined communication time. Here, the value H indicating the predetermined communication time is “a value indicating an average value of communication time required for transmitting the start notification of the application to be executed after receiving the application end notification in the roadside device”. It is.

Thereafter, the vehicle-mounted device 1 executes the application (step S305), and ends the application upon reception of the application end notification from the roadside device (step S306). The in-vehicle device 1 finishes the measurement of the application communication time G together with the end of the application (Step S307). The vehicle-mounted device 1 calculates an error amount I from the application communication time G based on the value H indicating the predetermined communication time received from the roadside device (step S308). The error amount I can diagnose the wireless communication function of the vehicle-mounted device 1 such that, for example, it can be determined that the communicable area between the vehicle-mounted device 1 and the road device has decreased due to a decrease in the reception sensitivity of the vehicle-mounted device 1. it can.
When the error amount I exceeds the allowable range (step S309), the vehicle-mounted device 1 outputs a sound, buzzer, light, etc. as a diagnostic result that the wireless communication function of the vehicle-mounted device 1 is abnormal. And the user is notified using the HMI function 6 such as the light output means 9 (step S310).

  As described above, according to the third embodiment, the vehicle-mounted device has the function of calculating the communication time G from the start to the end of one application, and the value H indicating the predetermined communication time notified from the road device Since the wireless communication function of the vehicle-mounted device is diagnosed from the error amount I, the wireless communication function of the vehicle-mounted device can be diagnosed even when a plurality of applications are executed on the same road device in the actual environment.

Embodiment 4 FIG.
In the third embodiment, the vehicle-mounted device has a function of calculating the communication time G from the start to the end of one application, and the vehicle-mounted device calculates the error amount I from the value H indicating the predetermined communication time notified from the road device. However, because the data processing speed inside the OBE differs depending on the OBE of each manufacturer, the application communication time becomes long (or short), and accurate diagnosis may not be possible. . For this reason, the fourth embodiment enables the diagnosis of the wireless communication function regardless of the application communication time.
Hereinafter, the fourth embodiment will be described with reference to the drawings.
The configuration of the DSRC in-vehicle device of the fourth embodiment is the same as that in FIG. However, in the fourth embodiment, the calculation function of the CPU 4 calculates the total amount of received data per application (predetermined physical quantity required for communication), thereby one application notified from the roadside device. An error amount with respect to the total transmission data amount per unit (a reference value of a predetermined physical amount required for communication) is calculated, and the state of the wireless communication function is diagnosed and notified.

FIG. 5 is a flowchart showing a procedure when the on-board DSRC device according to Embodiment 4 of the present invention diagnoses a wireless communication function.
Next, the operation of the DSRC vehicle-mounted device according to the fourth embodiment will be described with reference to FIG.
In a vehicle equipped with the DSRC on-vehicle device 1, it is assumed that the vehicle has entered the DSRC communication area with the on-road unit in a state where power is supplied from the vehicle-side power source 11 to the power circuit 10 of the DSRC on-vehicle device 1. Are connected by communication (step S401). After the communication connection, the road device transmits an application start notification to the vehicle-mounted device 1, and the application is started when the vehicle-mounted device 1 receives the application start notification (step S402). After the application starts, the road device transmits a value J indicating a predetermined data amount to the vehicle-mounted device 1. Here, the value J indicating the predetermined data amount is “in-vehicle device in order to complete an application to be executed by the on-road unit when communication is good and retransmission is not performed within the on-road unit communication area. Is a value indicating the total amount of data to be transmitted.

When the on-vehicle device 1 receives a value J indicating a predetermined amount of data from the road device (step S403), thereafter, the vehicle-mounted device 1 calculates a sum K of received data amounts from the road device until a notification of termination of the application being executed is received. (Step S404). When the on-vehicle device 1 executes the application (step S405) and receives an application end notification from the road device (step S406), the on-vehicle device 1 ends the calculation of the sum K of the amount of data received from the road device. (Step S407). The vehicle-mounted device 1 calculates an error amount L with respect to the total sum K of received data amounts with reference to a value J indicating a predetermined data amount (step S408). From the error amount L of the received data amount, for example, it can be determined that the sum L of the received data amount has increased because the roadside device has retransmitted due to a decrease in the transmission output of the on-vehicle device 1. The communication function can be diagnosed.
When the error amount L of the received data amount exceeds the allowable range (step S409), the on-vehicle device 1 indicates the diagnosis result that the wireless communication function of the on-vehicle device 1 is abnormal due to the difference, by voice, buzzer, and light. Are notified to the user using the HMI function 6 such as the sound output means 8 and the light output means 9 (step S410).

  As described above, according to the fourth embodiment, the vehicle-mounted device has the function of calculating the sum K of the amount of data received from the road device from the start to the end of one application, and the predetermined data amount notified from the road device Since the configuration of diagnosing the wireless communication function of the vehicle-mounted device is based on the error amount L with respect to the value J indicating that the wireless communication function of the vehicle-mounted device is diagnosed in the actual environment regardless of the data processing time inside the vehicle-mounted device. Can do.

Embodiment 5. FIG.
In the fourth embodiment, the vehicle-mounted device has a function of calculating the sum K of the amount of data received from the road device from the start to the end of one application, and a value J indicating a predetermined data amount notified from the road device. Although it was set as the structure which diagnoses the radio | wireless communication function of onboard equipment from error amount L, in this case, a diagnostic result can be notified to a user only immediately after performing road-to-vehicle communication. For this reason, the fifth embodiment is configured to notify the user of the diagnosis result even at times other than during road-to-vehicle communication.
The fifth embodiment will be described below with reference to the drawings.
The configuration of the DSRC vehicle-mounted device of the fifth embodiment is the same as that in FIG.

FIG. 6 is a flowchart showing a procedure when the on-board DSRC device according to Embodiment 5 of the present invention diagnoses the wireless communication function.
Next, the operation of the DSRC vehicle-mounted device according to the fifth embodiment will be described with reference to FIG.
In a vehicle equipped with the DSRC on-vehicle device 1, it is assumed that the vehicle has entered the DSRC communication area with the on-road unit in a state where power is supplied from the vehicle-side power source 11 to the power circuit 10 of the DSRC on-vehicle device 1. Assume that the communication execution and application execution, communication disconnection, and diagnosis of the wireless communication function of the vehicle-mounted device 1 are performed (step S501). At this time, the vehicle-mounted device 1 records the diagnosis result in the EEPROM 5 (step S502). When the user makes a diagnosis result notification request by the operation means 7 (step S503), the CPU 4 reads out the diagnosis result stored in the EEPROM 5 (step S504), and the diagnosis result is notified by voice, buzzer, light, etc. Is notified to the user by using the HMI function 6 such as the sound output means 8 and the light output means 9 (step S505).
Note that the diagnosis of the wireless communication function of the vehicle-mounted device 1 in step S501 is performed according to any one of the first to fourth embodiments.
Further, the memory for storing the diagnosis result is not limited to the EEPROM 5 and may be a non-volatile memory such as a flash memory.

  As described above, according to the fifth embodiment, since the diagnosis result is recorded in the EEPROM 5 every time the diagnosis of the wireless communication function of the vehicle-mounted device is performed, even if not immediately after the end of road-to-vehicle communication, When the user requests a diagnosis result, the vehicle-mounted device can notify the user of the diagnosis result.

It is a block block diagram which shows the DSRC onboard equipment by Embodiment 1-5 of this invention. It is a flowchart which shows the procedure in case the DSRC onboard equipment by Embodiment 1 of this invention diagnoses a radio | wireless communication function. It is a flowchart which shows the procedure in case the DSRC onboard equipment by Embodiment 2 of this invention diagnoses a radio | wireless communication function. It is a flowchart which shows the procedure in case the DSRC onboard equipment by Embodiment 3 of this invention diagnoses a radio | wireless communication function. It is a flowchart which shows the procedure in case the DSRC onboard equipment by Embodiment 4 of this invention diagnoses a radio | wireless communication function. It is a flowchart which shows the procedure in case the DSRC onboard equipment by Embodiment 5 of this invention diagnoses a radio | wireless communication function.

Explanation of symbols

1 DSRC OBE 2 Antenna 3 Communication circuit 4 CPU
5 EEPROM
6 HMI device 7 Operating means 8 Sound output means 9 Light output means 10 Power supply circuit 11 Vehicle-side power supply 12 External device I / F
13 External device 14 SAM
15 IC card I / F
16 IC card

Claims (5)

In a DSRC system that exchanges information by DSRC communication between a road machine installed on the road and an on-vehicle device mounted on the vehicle,
The road device notifies the vehicle-mounted device of a reference value of a predetermined physical quantity required for communication,
The vehicle-mounted device calculates a predetermined physical quantity required for the communication and calculates the predetermined physical quantity and the reference value of the predetermined physical quantity notified from the road device during the communication. Calculation means for calculating the error of the calculated predetermined physical quantity, diagnosis means for diagnosing the state of the wireless communication means based on the error calculated by the calculation means, and the wireless communication diagnosed by the diagnosis means A DSRC system comprising notification means for notifying a user of the state of the means.   The reference value of the predetermined physical quantity required for the communication notified by the road unit to the vehicle-mounted device is an average value of communication times obtained from a plurality of vehicle-mounted devices that have passed through the road device, and is calculated by the vehicle-mounted device. The DSRC system according to claim 1, wherein the predetermined physical quantity required for the communication is a communication time during which the vehicle-mounted device communicates with the roadside device.   The reference value of the predetermined physical quantity required for the communication notified by the road unit to the on-vehicle device is the total amount of data transmitted from the road device to the on-vehicle device by the communication, and is used for the communication calculated by the on-vehicle device. The DSRC system according to claim 1, wherein the predetermined physical quantity required is a received data quantity received by the vehicle-mounted device from the roadside device in the communication.   The reference value of the predetermined physical quantity required for the communication notified by the road unit to the on-vehicle device is the reference value of the predetermined physical quantity required for the communication for one application, and is required for the communication calculated by the on-vehicle device. The DSRC system according to claim 2 or 3, wherein the predetermined physical quantity is a predetermined physical quantity required for the communication for the application.   The on-vehicle device includes a non-volatile memory that stores the state of the wireless communication unit diagnosed by the diagnosis unit, and the on-vehicle device changes the state of the wireless communication unit according to a request from a user. The DSRC system according to any one of claims 1 to 4, wherein the DSRC system is read from a memory and notified to the user by the notification means.

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