JP2007036459A - Narrowcast onboard unit, narrowcast communication applied system, roadside-vehicle communication control method and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a security which does not allow the tapping of important information such as a personal identification number by detecting a roadside wireless unit in advance, even if an unauthorized roadside wireless unit that impersonates a roadside wireless unit installed for settlement is present. <P>SOLUTION: A narrowcast onboard unit employs such a configuration as detecting whether the roadside wireless unit (3' or 6) which is the other side of communication is a normal one or not in advance if the information such as a personal identification number that is inputted by a user is transmitted to the roadside wireless unit 3'. The narrowcast onboard unit mounted to a vehicle 5 performs search before the transmission of input information, and determines whether a roadside wireless unit having strong field intensity is present in the other frequency or not. If the other roadside wireless unit 3' is determined to be present, a roadside wireless unit 6 currently in communication is assumed to be an unauthorized roadside wireless unit, and the other frequency is assigned for re-connection. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an in-vehicle device for narrow area communication, a narrow area communication application system, a road-to-vehicle communication control method, and a program that perform, for example, fee settlement processing using narrow area communication such as DSRC (Dedicated Short Range Communications).

An automatic toll collection system (ETC: Electronic Toll Collection System) using wireless technology has been adopted for toll collection on toll roads.
In recent years, various services using DSRC, which is a wireless communication technology adopted in the ETC, have been proposed as application systems. In DSRC, the frequency of the radio wave transmitted from the roadside radio device and the frequency of the radio wave transmitted from the in-vehicle device for narrow area communication are assigned to one set of different frequency groups, and road-vehicle communication is performed using the set frequency. (Connect the car and the road by two-way communication). In DSRC, the frequency set is composed of a maximum of 7 sets.

In the above-described DSRC application system, a service that uses an IC card type credit card when purchasing a product through drive-through is currently being considered (see Non-Patent Document 1, for example). The same applies to parking lots and gas stations, not limited to drive-through. In this case, the system has functions of non-stop, cashless, and window close.
In the above-described DSRC application system, various types of payments that are conventionally performed using DSRC wireless communication while ensuring security are also known (see, for example, Patent Documents 1, 2, and 3).
Satoshi Amano, “Activities of DSRC Promotion Committee Working Group”, [online], September 17, 2004, Japan Radio Industry Association, [Search June 1, 2005], Internet <URL: http: // www. arib. or. jp / dsrc / shirase / img / 160917-shiryo2. pdf> Japanese Patent Laying-Open No. 2004-227055 (paragraph “0007”, FIG. 1) JP 2003-217097 A (paragraphs “0005” to “0011”, FIG. 1) JP 2002-170062 (paragraphs “0004” to “0008”, FIG. 1)

By the way, charge settlement by ETC does not require the user to input important information such as a card password. On the other hand, since it is assumed that charge payment using DSRC uses a normal credit card, it is assumed that input of important information such as a personal identification number is required.
Here, since DSRC communicates in a narrow area, it is possible to specify a place where the communication is performed, and is suitable for fee settlement.

  However, the fee settlement using the DSRC has the following problems. In the following description, a case where DSRC that performs fee settlement is applied to drive-through will be described. For example, an unauthorized performer installs an unauthorized roadside wireless device (illegal roadside wireless device) behind the scenes. And before the on-board equipment for narrow area communication installed in the car starts regular communication with the roadside radio installed on the road for fee settlement, it starts communication with the unauthorized roadside radio By doing so, it becomes possible for an unauthorized executor to appear as if it were a drive-through payment and to steal the entered user's personal identification number. Further, at this time, the illegal executor cooperates with the store clerk (private person), and once the credit card is deposited from the user for the reason of the communication failure, the card number is refrained when the settlement process is performed at the terminal. This makes it possible to steal a card number in addition to the above-described password. For this reason, security measures for preventing these are desired.

  The present invention has been made based on the above-described circumstances, and detects an unauthorized roadside wireless device in advance even if there is an unauthorized roadside wireless device impersonating a roadside wireless device installed for fee settlement. Accordingly, it is an object of the present invention to provide an in-vehicle device for narrow-area communication, a narrow-area communication application system, a road-to-vehicle communication control method, and a program in which security measures are taken so that important information such as a password is not stolen.

  In order to solve the above-described problems, the present invention determines whether or not a roadside radio serving as a communication partner is a regular roadside radio when transmitting important information such as a password entered by a user to the roadside radio. It was set as the structure which detects. Therefore, the frequency search is performed prior to the transmission of the input information described above, and it is determined whether there is another roadside radio having a strong electric field strength at another frequency. Here, it is determined that there is another roadside radio. When the determination is made, the roadside radio currently communicating is regarded as an unauthorized roadside radio and the frequency search is performed again.

  According to the present invention, even if there is an unauthorized roadside wireless device that constitutes a roadside wireless device installed for toll payment, by detecting the unauthorized roadside wireless device in advance, important information such as a personal identification number can be obtained. It is possible to provide an in-vehicle device for narrow area communication, a narrow area communication application system, a road-to-vehicle communication control method, and a program in which security measures are not taken.

[Narrow area communication application system]
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing an example of a narrow area communication application system according to an embodiment of the present invention.
In FIG. 1, reference numeral 1 is an in-vehicle device for narrow area communication (hereinafter referred to as a DSRC in-vehicle device 1) installed in a vehicle 5, and displays information generated and output by the DSRC in-vehicle device 1. The navigation system has a display device 2 and a car navigation system input device 4 for inputting important information such as a password to the DSRC in-vehicle device 1. The DSRC in-vehicle device 1 can perform DSRC wireless communication with the roadside wireless device 3 installed outside the vehicle (road) and bidirectionally communicate various information.
Assume that the DSRC in-vehicle device 1, the display device 2, and the input device 4 are provided in a car navigation system.
In the above-described embodiment of the present invention, the display device 2 and the input device 4 are assumed to have respective devices in the car navigation system. However, as shown in FIG. May be.

[In-vehicle device for narrow area communication (DSRC in-vehicle device)]
FIG. 2 is a block diagram showing an internal configuration of the in-vehicle device for narrow area communication (DSRC in-vehicle device) according to the embodiment of the present invention.
The DSRC in-vehicle device 1 according to the embodiment of the present invention includes a radio reception unit 11, a radio transmission unit 12, a communication control unit 13, an application execution control unit 14, an IC card connector 15, an input / output device 16, and The antenna 17 is configured.

The communication control unit 13 controls road-to-vehicle communication using DSRC, captures or transmits information transmitted / received wirelessly via the antenna 17, the wireless reception unit 11, and the wireless transmission unit 12, and a processing device (CPU). To the application execution control unit 14 configured by The application execution control unit 14 includes a credit settlement processing unit 140 that performs credit settlement and an ETC control unit 150 that performs toll collection on the toll road. In the embodiment of the present invention, details of the credit settlement processing unit 140 will be described later. Since the configuration and function of the ETC control unit 150 are the same as those of the credit settlement processing unit 140 in which the configuration and function related to security are omitted, description thereof will be omitted.
The IC card connector 15 has a slot into which an IC card type credit card (not shown) is inserted.
In FIG. 1, the display device 2 and the input device 4 are provided separately from the DSRC on-vehicle device 1, but as shown in FIG. 2, for example, the DSRC on-vehicle device 1 includes an input / output device 16 formed of a touch panel. May be. In the following description, it is assumed that the display device 2 and the input device 4 follow the configuration shown in FIG.

[Credit payment processing department]
FIG. 3 is a block diagram showing a functional development of the internal configuration of the credit settlement processing unit shown in FIG.
With reference to FIGS. 1 and 2, the function of the internal configuration of the credit settlement processing unit will be described along FIG.
The internal configuration of the credit settlement processing unit 140 is functionally divided into an input information processing unit 141, a frequency monitoring unit 142, a frequency allocation control unit 143, a security protection detection unit 144, and a highlight display control unit 145. Is done.

The input information processing unit 141 has a function of receiving important information such as a personal identification number input by the user operating the input device 4 and transmitting it to the roadside wireless device 3.
The frequency monitoring unit 142 performs a frequency search before transmitting the important information to the roadside wireless device 3 and detects whether there is another roadside wireless device having a strong electric field strength at another frequency. A function of notifying the frequency allocation control unit 143 is provided. When the frequency monitoring unit 142 determines that there is another roadside wireless device, the frequency allocation control unit 143 regards the currently communicating roadside wireless device as an unauthorized roadside wireless device, and causes the frequency monitoring unit 142 to re-frequency. It has a function to search.

  The security protection detection unit 144 has a function of detecting whether or not the communication path of the current road-to-vehicle communication is protected by security before transmitting the above-mentioned important information to the roadside wireless device 3 (at the time). Have. Whether or not it is protected by security can be determined by examining whether or not the transmitted radio wave is a radio wave that complies with the protocol of the application sublayer.

  The application sublayer is a DSRC platform that can be commonly used by a plurality of IP (Internet Protocol) / non-IP applications in each region. In the application sublayer, a security method according to a certain protocol is defined, and it is possible to detect whether or not the radio wave is protected by security by examining the protocol of the radio wave transmitted.

  Further, the highlight display control unit 145 displays the detection result by the security protection detection unit 144 on the display device 2 by distinguishing it from other display contents by, for example, highlight display such as color display or blinking display of a pop-up frame. Has function.

[Operation of in-vehicle equipment for narrow area communication]
FIG. 4 is a flowchart cited for explaining the operation of the in-vehicle device for narrow area communication according to the embodiment of the present invention. Here, it is assumed that a product is purchased through drive-through or the like.
Hereinafter, the operation of the narrowband communication application system according to the embodiment of the present invention will be described in detail along the flowchart shown in FIG. 4 with reference to FIG. 1, FIG. 2 and FIG.

(start)
When the DSRC in-vehicle device 1 enters the communication area of the roadside wireless device 3, it starts the following processing.
After activation, the DSRC in-vehicle device 1 starts frequency search when the frequency monitoring unit 142 is activated (step S401).
Next, the frequency monitoring unit 142 sets an initial value of the frequency stored in the frequency monitoring unit 142 in advance (step S402).

(Frequency search, acquisition)
Then, the frequency monitoring unit 142 searches for the seven sets of frequencies in order from the initial value set in step S402, and from the roadside wireless device 3 via the antenna 17, the wireless reception unit 11, and the communication control unit 13. It is determined whether or not a radio wave has been received (step S403).
When the frequency monitoring unit 142 determines that the radio wave from the roadside radio device 3 has been received (step S403 → “Yes”), the frequency monitoring unit 142 then checks the electric field strength of the received radio wave, It is determined whether or not the electric field strength is greater than or equal to a preset threshold value (step S404).
Here, when it is determined that the radio wave has an electric field strength equal to or higher than a preset threshold value (step S404 → “Yes”), the frequency monitoring unit 142 instructs the communication control unit 13 to capture the radio wave. . Then, the instructed communication control unit 13 takes in the radio wave satisfying the condition of step S404 via the antenna 17 and the wireless reception unit 11 (determines the frequency), and the frequency monitoring unit 142 ends the frequency search. (Step S406), road-to-vehicle communication is started (Step S407).
In step S403, the frequency monitoring unit 142 determines that the radio wave from the roadside wireless device 3 is not received (step S403 → “No”), or determines in step S404 that the electric field strength does not reach the threshold value. In this case (step S404 → “No”), the frequency monitoring unit 142 changes the frequency by changing the set value of the frequency to be searched (step S405), returns to the process of step S403, and repeats the processes after step S403. .

(Input important information, search for other frequencies)
After the start of road-to-vehicle communication, the process proceeds to fee settlement.
First, the input information processing unit 141 determines whether or not important information such as a personal identification number (information in claims) is input to the DSRC in-vehicle device 1 by the input device 4 (step S408).
If important information is not input (step S408 → “No”), no special processing related to security is required, so the process proceeds to step S411, and road-to-vehicle communication is continued.
When the important information is input (step S408 → “Yes”), the input information processing unit 141 notifies the frequency monitoring unit 142 of the fact, and the notified frequency monitoring unit 142 notifies the communication control unit 13 in step S404. Is searched for a frequency (other frequency) other than the frequency of the radio wave taken in, and it is determined whether or not a radio wave of another frequency whose electric field strength is greater than a preset threshold value has been received (step S409).

When it is determined that a radio wave having another frequency greater than a preset threshold value is received (step S409 → “Yes”), the frequency monitoring unit 142 notifies the frequency allocation control unit 143 to that effect. The notified frequency allocation control unit 143 considers that the currently-communication roadside wireless device 3 is an unauthorized roadside wireless device, instructs the frequency monitoring unit 142 to search for the frequency again, and returns to the process of step S401. .
When it is determined that a radio wave having another frequency greater than a preset threshold is not received (step S409 → “No”), the frequency monitoring unit 142 notifies the input information processing unit 141 to that effect. To do. The notified input information processing unit 141 transmits the important information to the roadside wireless device 3 via the communication control unit 13, the wireless transmission unit 12, and the antenna 17 (step S410), and the roadside wireless device 3 performs the step. In S406, road-to-vehicle communication with the DSRC in-vehicle device is continued using the frequency of the captured radio wave (step S411).
Then, when the road-to-vehicle communication ends (step S412), the process ends.

[Operation of in-vehicle device for narrow area communication with security judgment]
FIG. 5 is a flow chart quoted for explaining the operation of the in-vehicle device for narrow area communication according to another embodiment of the present invention.
With reference to FIG. 3, the operation of the DSRC in-vehicle apparatus according to another embodiment of the present invention will be described along FIG.
Up to the start of road-to-vehicle communication (steps S501 to S508) is the same as the processing (steps S401 to S408) of the embodiment of the present invention shown in FIG.

In step S509, the security protection detection unit 144 determines whether or not the radio wave transmitted from the communication control unit 13 via the frequency monitoring unit 142 is protected by security.
When it is determined that the radio wave is not protected by security (step S509 → “Yes”), the security protection detection unit 144 notifies the frequency allocation control unit 143 to that effect. The notified frequency allocation control unit 143 considers that the currently-communication roadside wireless device 3 is an unauthorized roadside wireless device, instructs the frequency monitoring unit 142 to search for the frequency again, and returns to the process of step S501. .
In other cases (step S509 → “No”), the process proceeds to step S510.

  The processing of steps S510 to S512 is the same as the processing of steps S409 to S411 of the embodiment of the present invention shown in FIG.

  Although not shown in the flowchart, the highlighting control unit 145 displays the detection result (the result of step S509 in FIG. 5) by the security protection detection unit 144 on the display device 2 separately from other display contents. It is also possible to do. Specifically, the highlighting control unit 145 displays the pop-up display frame in blue when the communication path is protected by security, and displays the pop-up display frame in red when the communication path is not protected by security. Display on the device 2.

FIG. 6 is a diagram cited for explaining the flow of processing of the narrow area communication application system according to the embodiment of the present invention.
The flow of processing of the DSRC application system according to the embodiment of the present invention will be described along FIG. 6 with reference to FIG. 1, FIG. 3, and FIG.
The DSRC in-vehicle device 1 mounted on the vehicle 5 can determine whether or not the communication path for road-to-vehicle communication is protected by security, and this information is transmitted to the display device 2 by the highlighting control unit 145. It shall be added to the information to be performed. The legitimate roadside wireless devices 3 and 3 ′ pass through a communication path protected by security, but the unauthorized roadside wireless device 6 often passes through a communication path not protected by security. When the highlighting control unit 145 receives information indicating that the communication path is protected by security, for example, as illustrated in FIG. 6, the pop-up display frame is displayed in blue (display screen 2 a), and security is displayed. If the communication path is not protected, the pop-up display frame is displayed in red (display screen 2b) and displayed on the display device 2.

First, the DSRC in-vehicle device 1 starts communication with the roadside wireless device 3 at the point A and starts searching for a frequency.
If the DSRC in-vehicle device 1 captures the frequency of the unauthorized roadside wireless device 6 at the B point, the unauthorized roadside wireless device 6 impersonates the regular roadside wireless device 3 'at the C point, and a communication path without security. Can be used to display the password input screen on the display device 2. At this time, the highlighting unit 145 notifies the information transmitted to the display device 2 that the communication path is not secure, and the display device 2 that has received the information displays a pop-up frame in red. This makes it possible to give attention to the user. By confirming the display, the user can prevent damage caused by fraud by stopping inputting the password or notifying the store clerk of the situation.

  Here, in order to further understand the embodiment of the present invention described with reference to FIGS. 4 and 5, in the sense of comparison, FIG. 7 shows a narrow-area communication application system in the case where fraud by impersonation is performed. FIG. 8 is a flowchart showing the flow of DSRC communication processing by the DSRC in-vehicle device 1 when communication is performed using a communication path without security protection.

  In FIG. 7, first, the user operates the DSRC on-vehicle device 1 (see FIG. 1) mounted on the vehicle 5 at the order gate at the point A (roadside radio device 3) to perform DSRC communication, and the product (here, Order hamburger). At this time, a display screen 2 c is displayed on the display device 2. The regular process is to receive the product at point C and enter the credit card PIN. However, the unauthorized performer installed the unauthorized roadside wireless device 6 at the B point between the A point and the C point, and was set to communicate with the roadside wireless device 3 ′ at the C point at a different frequency. To do. As a result, the DSRC in-vehicle device 1 installed in the vehicle starts searching for the next roadside wireless device after the communication is completed at the point A, and captures the unauthorized roadside wireless device 6 when entering the point B. It will be.

  Since the DSRC in-vehicle device 1 once captures the unauthorized roadside wireless device 6, it continues to capture the unauthorized roadside wireless device 6 for a certain period of time, and therefore continues to communicate with the unauthorized roadside wireless device 6 even if the vehicle moves to the point C. It will be. At this time, the unauthorized roadside radio 6 impersonates the legitimate roadside radio 3 'at the point C, and displays a password input screen (display screen 2d) on the display device 2 using a non-security communication path. By inputting the personal identification number, the unauthorized person can easily see the personal identification number.

FIG. 8 is a flowchart quoted for explaining the operation of the in-vehicle device for narrow area communication according to the comparative example of the present invention.
With reference to FIG. 7, the operation of the DSRC in-vehicle apparatus according to the comparative example of the present invention will be described along FIG.
8, steps S801 to S807 and step S809 are the same as the processes in steps S401 to S407 and step S412 in FIG. In step S808, the password is processed by sending the personal identification number to the roadside wireless device 3 '.
As shown in the flowchart of FIG. 8, the DSRC in-vehicle device 1 performs a frequency search, and once the roadside wireless device is captured, communication with the roadside wireless device is continued until the road-to-vehicle communication is completed. The That is, if the DSRC in-vehicle device 1 captures the unauthorized roadside wireless device 6 at the point B, the DSRC in-vehicle device 1 that performs the process shown in FIG. 8 performs the unauthorized roadside wireless device 6 until the road-to-vehicle communication is completed. Will communicate with. Once the frequency is captured, the DSRC in-vehicle device 1 locks the frequency, and communication with other frequencies becomes impossible (“×” in FIG. 7).

Returning to the description of FIG.
On the other hand, in the above-described embodiment of the present invention, when important information such as a personal identification number input by the user is transmitted to the roadside wireless device, whether the roadside wireless device to be a communication partner in advance is a regular roadside wireless device. The structure which detects whether or not is adopted. Therefore, after the important information is input to the DSRC in-vehicle device 1, the frequency search is performed again to determine whether or not there is a radio wave having another frequency whose electric field strength is greater than a preset threshold value. When it is determined that there is another roadside radio (ie, a regular roadside radio 3 ′), the unauthorized roadside radio 6 that is currently communicating is regarded as an illegal roadside radio, and another frequency is assigned to reconnect. The function to perform was given.

  Since the vehicle 5 is always moving, the vehicle 5 approaches the regular roadside wireless device 3 ′ after capturing the unauthorized roadside wireless device 6. At this time, if it is determined whether or not there is a radio wave of another frequency whose electric field intensity is greater than a preset threshold value, the regular roadside radio 3 ′ is better than the unauthorized roadside radio 6. Since it exists near the vehicle 5, a radio wave having a strong frequency (high electric field strength) different from the frequency previously captured at the point B is newly detected. If there is no unauthorized roadside radio device 6, this cannot happen. Therefore, the DSRC in-vehicle device 1 determines that the roadside wireless device that has been communicating so far is the unauthorized roadside wireless device 6, and performs a frequency search again.

  As a result, even if there is an unauthorized roadside wireless device 6 impersonating the roadside wireless device 3 ′ installed for settlement, important information such as a password is stolen by detecting the unauthorized roadside wireless device 6 in advance. It is possible to provide a DSRC in-vehicle device and a DSRC application system that have been provided with security measures that will not occur.

At this time, the following processing can also be performed.
First, the roadside radio 3 presets the traveling speed of the vehicle 5 between the roadside radio 3 and the adjacent roadside radio 3 ′. And the roadside radio | wireless machine 3 always transmits the information regarding the set traveling speed of the vehicle 5 with respect to the circumference | surroundings. When the vehicle 5 reaches the point A, the DSRC on-vehicle device 1 receives this information, and may display on the display device 2 (see FIG. 1) that the vehicle travels at this speed or more. However, you may send the instruction | indication which keeps the speed of the vehicle 5 to below the above-mentioned traveling speed to each control part of the vehicle 5 which is not shown in figure.
Further, the DSRC in-vehicle device 1 may set the above-described traveling speed, and when the DSRC in-vehicle device 1 captures the roadside wireless device 3 at the point A, the above-described traveling speed may be displayed on the display unit. In addition, an instruction may be sent to each control unit of the vehicle 5 (not shown) so that the speed of the vehicle 5 does not fall below the traveling speed described above.

  By performing such processing, for example, when the traveling speed of the vehicle 5 is very slow, the DSRC in-vehicle device 1 does not capture the roadside wireless device 3 ′ and the illegal roadside wireless device 6 after supplementing the roadside wireless device 3. The state where the roadside wireless device 3 is captured again can be avoided.

Note that the functions of the input information processing unit 141, frequency monitoring unit 142, frequency allocation control unit 143, security protection detection unit 144, and highlight display control unit 145 shown in FIG. 14 is realized by sequentially reading and executing a program recorded in a storage device (not shown) using the input / output device 16.
Each functional block constituting the application execution control unit 14 is implemented in seven layers that realize the DSRC protocol, except for the security protection detection unit 144. The security protection detection unit 144 is mounted on the application sublayer.

  INDUSTRIAL APPLICABILITY The present invention can be used for all vehicle communication devices that perform payment processing using roadside wireless devices installed on the road side and wireless communication.

It is a figure which shows an example of the narrow region communication application system concerning embodiment of this invention. It is a block diagram which shows the internal structure of the vehicle-mounted apparatus for narrow area communication (DSRC vehicle-mounted apparatus) concerning embodiment of this invention. It is the block diagram which expanded and showed the function of the internal structure of the credit payment process part shown in FIG. It is the flowchart quoted in order to demonstrate operation | movement of the vehicle-mounted apparatus for narrow region communication concerning embodiment of this invention. It is the flowchart quoted in order to demonstrate operation | movement of the vehicle-mounted apparatus for narrow region communication concerning other embodiment of this invention. It is the figure quoted in order to demonstrate the flow of the narrow area communication application system concerning embodiment of this invention. It is a figure which shows schematically the flow of operation | movement of a narrow-area communication application system when the fraud by impersonation is performed. It is the flowchart quoted in order to demonstrate operation | movement of the vehicle equipment for narrow area communication concerning the comparative example of this invention.

Explanation of symbols

1 DSRC in-vehicle device (in-vehicle device for narrow area communication)
DESCRIPTION OF SYMBOLS 2 Display apparatus 3 Roadside radio | wireless machine 4 Input device 6 Illegal roadside radio | wireless machine 11 Wireless receiving part 12 Wireless transmission part 13 Communication control part 14 Application execution control part 15 IC card connector 140 Credit payment processing part 141 Input information processing part 142 Frequency monitoring part 143 Frequency allocation control unit 144 Security protection detection unit 145 Highlight display control unit 150 ETC control unit

Claims (6)

The on-vehicle device for narrow-area communication that performs road-to-vehicle communication by narrow-area communication assigns the frequency of the radio wave transmitted from the roadside radio device and the frequency of the radio wave transmitted from the on-vehicle device for narrow-area communication to a set of different frequencies, The vehicle for narrow area communication that searches for the radio frequency transmitted by the roadside radio and monitors the intrusion into the communication area of the roadside radio when performing road-to-vehicle communication using one set of frequencies. Machine,
A frequency monitor that performs frequency search when transmitting information to the roadside radio, and detects whether there is another roadside radio with stronger electric field strength than the frequency at other frequencies;
When it is determined by the frequency monitoring unit that the other roadside radio is present, a frequency allocation control unit that causes the frequency monitoring unit to perform frequency search again;
An in-vehicle device for narrow area communication characterized by comprising: When transmitting information to the roadside radio, further comprising a security protection detection unit for detecting whether or not the communication path of the road-to-vehicle communication is protected by security,
The frequency monitoring unit, when the security protection detection unit detects that the communication path is not protected, performs the frequency search again, and another roadside radio having a strong electric field strength at another frequency. The in-vehicle device for narrow area communication according to claim 1, wherein it is detected whether or not there is. The in-vehicle device for narrow area communication according to claim 2, further comprising: an emphasis display control unit that displays a detection result by the security protection detection unit on a display device. The on-vehicle device for narrow-area communication that performs road-to-vehicle communication by narrow-area communication assigns the frequency of the radio wave transmitted from the roadside radio device and the frequency of the radio wave transmitted from the on-vehicle device for narrow-area communication to a set of different frequencies, A narrow area communication application system that searches for a radio frequency transmitted by the roadside radio and monitors the roadside radio to enter a communication area when performing road-to-vehicle communication using one set of frequencies. There,
The roadside radio that performs road-to-vehicle communication using one radio frequency assigned from a predetermined radio frequency; and
When transmitting information to the roadside radio, frequency search is performed, and it is detected whether there is another roadside radio having stronger electric field strength than the frequency at another frequency, and the other roadside radio is When it is determined that there is an in-vehicle device for narrow area communication that performs frequency search again,
A narrow area communication application system characterized by comprising: The on-vehicle device for narrow-area communication that performs road-to-vehicle communication by narrow-area communication assigns the frequency of the radio wave transmitted from the roadside radio device and the frequency of the radio wave transmitted from the on-vehicle device for narrow-area communication to a set of different frequencies, When performing road-to-vehicle communication using a set of frequencies, a road-to-vehicle communication control method for searching for a radio frequency transmitted by the roadside radio and monitoring entry into the communication area of the roadside radio. There,
The roadside radio is
Performing road-to-vehicle communication with the in-vehicle device for narrow area communication using one radio frequency allocated from among predetermined radio frequencies;
The in-vehicle device for narrow area communication is
When performing a frequency search when transmitting information to the roadside radio, detecting whether there is another roadside radio having a stronger electric field strength than the frequency at another frequency;
The in-vehicle device for narrow area communication is
When it is determined that the other roadside wireless device is present, a step of performing a frequency search again;
A road-to-vehicle communication control method comprising: The on-vehicle device for narrow-area communication that performs road-to-vehicle communication by narrow-area communication assigns the frequency of the radio wave transmitted from the roadside radio device and the frequency of the radio wave transmitted from the on-vehicle device for narrow-area communication to a set of different frequencies, An in-vehicle device for narrow area communication that searches for a radio frequency transmitted by the roadside radio and monitors an intrusion into the communication area of the roadside radio when performing road-to-vehicle communication using a set of frequencies. A program used for
A process of performing frequency search when transmitting information to the roadside radio, and detecting whether there is another roadside radio with stronger electric field strength than the frequency at other frequencies;
When it is determined that there is another roadside radio device, a process for searching for a frequency again,
A program that causes a computer to execute.

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