JP4213620B2 - DSRC OBE - Google Patents

Description

  The present invention is used for ETC (Electronic Toll Collection System), parking lot management system, private billing system (gas station, drive-through), etc., and DSRC that performs narrow area communication with roadside devices (Dedicated Short-Range Communication) This invention relates to a vehicle-mounted device.

2. Description of the Related Art In recent years, a DSRC on-vehicle device that performs communication between a vehicle and a roadside device (roadside antenna) installed on a traveling road and transmits and receives information for billing and parking management is well known. In general, the reception sensitivity of the DSRC in-vehicle device is set to be constant regardless of whether or not it is in a communication area where communication between road vehicles can be performed. For this reason, the DSRC in-vehicle device adjusts the reception sensitivity so as to be compatible with the ETC for which the service has been started first.
However, when the environmental conditions of road-to-vehicle communication such as the vehicle-mounted antenna position, the temperature of the DSRC vehicle-mounted device (reception sensitivity decreases at high temperatures), vehicle driving conditions, etc. are bad, for example, when passing the ETC fee gate on a sunny day in summer If the vehicle passes through the lane edge of the ETC toll gate when the vehicle-mounted antenna is installed from the A-pillar and the DSRC vehicle-mounted device is placed on the dashboard, road-to-vehicle communication becomes difficult. . For this reason, in road-to-vehicle communication, it is necessary to adjust the reception sensitivity of the DSRC in-vehicle device to obtain an appropriate reception sensitivity.
Conventionally, as a DSRC in-vehicle device that meets such requirements, a DSRC in-vehicle device that prevents communication errors by increasing reception sensitivity during road-to-vehicle communication with a roadside device has been proposed. (See Patent Document 1)

In addition, when road-to-vehicle communication is performed using a conventional DSRC vehicle-mounted device in a closed space such as an underground parking lot, there are restrictions on the height and transmission output of the roadside antenna. It is difficult to give For example, the height of the roadside antenna is about 2.5 m in an underground parking lot with an ETC of 6 m. In this case, in order to secure a communication area such as ETC, it is necessary to increase the transmission power of the roadside antenna. However, in a closed space such as an underground parking lot, increasing the transmission power of the roadside antenna increases the effect of multipath, increasing the field strength drop point in the road-to-vehicle communication area. In addition, there is a case where the influence of the radio wave jump becomes large, and the rear vehicle receives the saddle radio wave that the preceding vehicle performs road-to-vehicle communication, and the road vehicle communicates with the rear vehicle. Therefore, when the reception sensitivity of the DSRC in-vehicle device is made constant, the road-vehicle communication area becomes narrow.
Moreover, when the environmental conditions of road-to-vehicle communication are bad, the road-to-vehicle communication area of the DSRC on-board device may be further narrowed, and road-to-vehicle communication may not be possible. In this case, the reception sensitivity cannot be adjusted during road-to-vehicle communication.

JP 2001-273534 A (pages 4-8, FIG. 1)

Since the conventional DSRC in-vehicle device has a constant reception sensitivity of the DSRC on-vehicle device as described above, it is necessary to set the reception sensitivity of the DSRC on-vehicle device to an appropriate level during road-to-vehicle communication.
However, in the case of increasing the reception sensitivity during road-to-vehicle communication with the roadside machine of Patent Document 1, when performing road-to-vehicle communication using services other than ETC such as an underground parking lot, depending on conditions such as the vehicle-mounted antenna position and vehicle driving conditions In some cases, the radio wave itself cannot be received, and the reception sensitivity of the on-board DSRC device cannot be adjusted.

  The present invention has been made to solve the above-described problems. Other services such as an ETC and an underground parking lot management system can be received, and the road-vehicle distance can be reduced without adjusting the reception sensitivity of the on-board DSRC device. An object of the present invention is to obtain a DSRC in-vehicle device that can prevent a communication error.

In the DSRC in-vehicle device according to the present invention, the DSRC on-vehicle device mounted on a vehicle and performing narrow-area communication with a roadside device has different antenna characteristics and performs narrow-area communication with the roadside device. two vehicle antenna changeover switch for switching the two vehicle-mounted antenna, before starting communication with the roadside device, the two vehicle-mounted antenna with periodically switched, during communication with the roadside device, in one of the in-vehicle antenna A switch control unit that controls the changeover switch to be fixed, an AID determination unit that is included in the information transmitted from the roadside device and that indicates an application ID indicating the type of application of the roadside device, and an application ID of the AID determination unit Based on the determination, it is determined which of the two in-vehicle antennas is fixed, and this determination result is switched to A switch judging means for transmitting to the control unit,
At the start of communication with the roadside device, the switch control unit temporarily fixes the vehicle-mounted antenna to one vehicle-mounted antenna, and continues to fix the vehicle-mounted antenna temporarily fixed according to the determination result of the switch determination unit, or cycles two vehicle-mounted antennas. The changeover switch is controlled so as to be switched automatically .

As described above, the present invention is a DSRC in-vehicle device that is mounted on a vehicle and performs narrow-area communication with a roadside device, and has different antenna characteristics and performs narrow-area communication with a roadside device. two vehicle antenna changeover switch for switching the two vehicle-mounted antenna, before starting communication with the roadside device, the two vehicle-mounted antenna with periodically switched, during communication with the roadside device, in one of the in-vehicle antenna A switch control unit that controls the changeover switch to be fixed, an AID determination unit that is included in the information transmitted from the roadside device and that indicates an application ID indicating the type of application of the roadside device, and an application ID of the AID determination unit Based on the determination, it is determined which of the two in-vehicle antennas is fixed, and this determination result is sent to the switch control unit. A switch judging means,
At the start of communication with the roadside device, the switch control unit temporarily fixes the vehicle-mounted antenna to one vehicle-mounted antenna, and continues to fix the vehicle-mounted antenna temporarily fixed according to the determination result of the switch determination unit, or cycles two vehicle-mounted antennas. Since the changeover switch is controlled so as to be switched automatically, by switching and using the two on-vehicle antennas, stable road-to-vehicle communication is possible, and road-to-vehicle communication errors can be prevented.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram showing a DSRC on-vehicle device according to Embodiment 1 of the present invention.
In FIG. 1, the vehicle-mounted antenna 1 of the DSRC vehicle-mounted device has an antenna characteristic suitable for an ETC application (AID = 14) and an antenna characteristic suitable for a DSRC application (AID = 18). The AID 14 antenna 11 is composed of an AID 18 antenna 12 having different antenna gain and directivity, and receives a radio wave transmitted by the roadside device and transmits it to the changeover switch 2. The change-over switch 2 switches between the AID 14 antenna 11 and the AID 18 antenna 12 and fixes the in-vehicle antenna 1. Moreover, until the radio wave is received from the roadside device, the vehicle-mounted antenna 1 is switched periodically. At the start of communication, the changeover switch 2 is fixed, and the radio wave transmitted from the vehicle-mounted antenna 1 is transmitted to the RF unit 3. The RF unit 3 converts the radio wave received by the vehicle-mounted antenna 1 into analog data, and transmits the analog data to the modem unit 4. The modem unit 4 converts the analog data converted by the RF unit 3 into digital data, and transmits the digital data to the DSRC on-vehicle device control unit 51 of the data processing unit 5.

The DSRC OBE control unit 51 of the data processing unit 5 transmits an AID (application ID) indicating the type of application of the roadside device included in the signal transmitted from the roadside device to the AID determination unit 52. The AID determination unit 52 determines the AID received from the DSRC on-board unit control unit 51 and transmits the determination result to the switch determination unit 53. The switch determination unit 53 determines which in-vehicle antenna 1 is used based on the determination result of the AID determination unit 52, and transmits the determination result to the switch control unit 6. The data processing unit 5 includes the DSRC on-board unit control unit 51, an AID determination unit 52, and a switch determination unit 53.
The switch control unit 6 transmits a switching signal to the switch 2 based on the determination result of the switch determination unit 53. When a radio wave is received from the roadside device, the changeover switch 2 is fixed once at the same time as the radio wave reception signal is received from the DSRC onboard unit control unit 51 of the data processing unit 5. Also, a switch signal indicating which switch is being used is received from the changeover switch 2, and this switch signal is transmitted to the switch determination means 53.

FIG. 2 is a flowchart showing processing of the data processing unit of the DSRC on-vehicle device according to Embodiment 1 of the present invention.
Next, the operation of the first embodiment will be described with reference to FIG.
When a vehicle equipped with a DSRC vehicle-mounted device enters a communication area that provides services via road-to-vehicle communication such as ETC or an underground parking lot management system, the DSRC vehicle-mounted device receives the radio waves transmitted by the roadside device, The device controller 51 proceeds from the switch cycle switching process (step 551) to the radio wave reception process (step 552). At this time, the radio wave reception process (step 552) performs the program process and transmits the AID included in the digital data to the AID determination means 52 to start the AID determination process (step 553) and simultaneously receive the radio wave. The changeover switch 2 is temporarily fixed by transmitting a radio wave reception signal indicating that it has been performed to the switch control unit 6.

In the AID determination process (step 553), the AID is actually analyzed. When the AID is 14, the AID14 switch determination process (step 554) is performed. When the AID is 18, the AID18 switch determination process (step 555) is performed. ). The switch determination process for AID14 (step 554) is sent from the switch control unit 6 as information indicating which switch the switch 2 is fixed to when receiving radio waves, so that the information of the switch control unit 6 is displayed. In the case of the switch for AID 14, the changeover switch 2 is kept fixed. When the information of the switch control unit 6 is the AID 18 switch, the process proceeds to the switch cycle switching process (step 551) again.
Similarly, in the switch determination processing for AID 18 (step 555), information about which switch is fixed by the switch 2 is sent from the switch control unit 6 at the time of radio wave reception. In the case of the switch for AID 18, the changeover switch 2 is kept fixed. When the information of the switch control unit 6 is the switch for AID14, the process proceeds to the switch cycle switching process (step 551) again.

According to the first embodiment, since two on-vehicle antennas having different parameters are switched and used, a stable road-to-vehicle communication is possible in a radio wave environment, and a DSRC on-vehicle device that prevents road-to-vehicle communication errors is obtained. There is an effect.
In addition, the AID determination means determines whether the AID included in the information transmitted from the roadside device is an ETC application or a DSRC application, and switches the vehicle-mounted antenna using the determination result. In addition, it is possible to easily determine the type of the DSRC service, and it is possible to perform appropriate on-vehicle antenna switching based on the determination result.

Embodiment 2. FIG.
In the first embodiment, if the result of the AID determination means 52 and the type of the in-vehicle antenna 1 do not match, the switch may be switched periodically as many times as possible, and stable communication may not be possible. Therefore, the second embodiment enables the switch to be fixed even if the result of the AID determination means 52 and the type of the in-vehicle antenna 1 are different.
FIG. 3 is a block diagram showing a DSRC vehicle-mounted device according to Embodiment 2 of the present invention.
In FIG. 3, 1 to 6, 11, 12, 51, 52 are the same as those in FIG. In FIG. 3, a counter function for counting how many times the determination is made is added to the switch determination means 53.

FIG. 4 is a flowchart showing processing of the data processing unit of the on-board DSRC device according to Embodiment 2 of the present invention.
Next, the operation of the second embodiment will be described with reference to FIG.
When a vehicle equipped with a DSRC vehicle-mounted device enters a communication area that provides services via road-to-vehicle communication such as ETC or an underground parking lot management system, the DSRC vehicle-mounted device receives the radio waves transmitted by the roadside device, The device controller 51 proceeds from the switch cycle switching process (step 551) to the radio wave reception process (step 552). At this time, the radio wave reception process (step 552) performs the program process and transmits the AID included in the digital data to the AID determination means 52, thereby starting the AID determination process (step 553) and simultaneously transmitting the radio wave. By transmitting a radio wave reception signal indicating reception to the switch control unit 6, the changeover switch 2 is temporarily fixed.

In the AID determination process (step 553), the AID is actually analyzed. When the AID is 14, the AID14 switch determination process (step 554) is performed. When the AID is 18, the AID18 switch determination process (step 555) is performed. ). In the switch determination process for AID14 (step 554), information on which switch is fixed by the switch 2 is sent from the switch control unit 6 at the time of radio wave reception, so the information of the switch control unit 6 is the switch for AID14. In this case, the process proceeds to a switch determination number reset process (step 558). If the information in the switch control unit 6 is a switch for AID18, the process proceeds to a switch determination number process (step 556).
Similarly, in the switch determination processing for AID18 (step 555), information on which switch is fixed to which switch 2 is fixed at the time of radio wave reception is sent from the switch control unit 6, so the information of the switch control unit 6 is AID18. In the case of a switch for a switch, the process proceeds to a switch determination count reset process (step 558), and when the information in the switch control unit 6 is an AID14 switch, the process proceeds to a switch determination count process (step 557).

The switch determination number process (step 556) and the switch determination number process (step 557) count how many times the AID14 switch determination process (step 554) and the AID18 switch determination process (step 555) have passed, respectively. If it is equal to or greater than the set value, the process proceeds to a switch determination number reset process (step 558). If it is less than a certain set value, the process proceeds to a switch determination number increment process (step 559).
In the switch determination number reset process (step 558), the switch determination number of the switch determination number process (step 556) and the switch determination number process (step 557) is set to 0, and the switch is kept fixed. In the switch determination number increment process (step 559), 1 is added to the switch determined numerical value, and the process proceeds to the switch cycle switching process (step 551) again.

Here, the setting values used in the switch determination number process (step 556) and the switch determination number process (step 557) are erroneous communication (two types of antenna characteristics), for example, in the case of ETC road-to-vehicle communication (AID = 14). Therefore, it may be set large or not to be processed in order to prevent a situation in which the rear vehicle receives outside the original communication area.
In addition, in a service using AID = 18 such as an underground parking lot, the radio wave environment (the communication area is narrower than ETC) may be bad. Therefore, stable road-to-vehicle communication can be obtained by using two types of vehicle-mounted antennas.

  According to the second embodiment, switching to an appropriate vehicle-mounted antenna is performed based on the AID determined by the AID determination unit and the number of times of AID determination, so that there is an effect that a DSRC vehicle-mounted device that prevents road-to-vehicle communication errors can be obtained. .

Embodiment 3 FIG.
In the third embodiment, in the first and second embodiments, when the time set by the timer control unit 54 has elapsed for the fixed release time of the on-vehicle antenna changeover switch 2, no-reception communication between the road and the vehicle is performed. When the specified time has elapsed, it is assumed that the in-vehicle device has received DSRC service end information, and after the changeover switch 2 is unfixed, the in-vehicle antenna 1 that is in the initial state is periodically switched.

FIG. 5 is a block diagram showing a DSRC on-vehicle device according to Embodiment 3 of the present invention.
In FIG. 5, 1-6, 11, 12, 51-53 are the same as those in FIG. In FIG. 5, the data processing unit 5 is provided with a timer control unit 54 having an A timer 71 and a B timer 72.
The DSRC OBE control unit 51 of the data processing unit 5 transmits timer information to the timer control unit 54 at the time of data reception at the initial initial connection, and at the same time sets a timer for each data reception.
The timer control unit 54 has an A timer 71 that sets time during initial communication and a B timer 72 that sets time for each reception. When timer information is received from the DSRC OBE control unit 51, The A timer 71 is set only for the time necessary and sufficient for communication. A necessary and sufficient time is set in the B timer 72 every time data is received by road-to-vehicle communication. When either the A timer 71 or the B timer 72 expires, the timer expiration information is immediately transmitted to the switch control unit 6.
When timer expiration information is transmitted from the timer control unit 54, the switch control unit 6 quickly returns the changeover switch 2 to the initial state.

FIG. 6 is a flowchart showing processing of the data processing unit of the DSRC on-vehicle device according to Embodiment 3 of the present invention.
Next, the operation of the third embodiment will be described with reference to FIG.
When a vehicle equipped with a DSRC vehicle-mounted device enters a communication area that provides services through road-to-vehicle communication such as ETC or an underground parking lot management system, the DSRC vehicle-mounted device receives the radio wave transmitted by the roadside device. The control unit 51 proceeds from the switch cycle switching process (step 551) to the radio wave reception process (step 552). At this time, the radio wave reception process (step 552) performs a program process and transmits the AID included in the digital data to the AID determination means 52, and simultaneously transmits a signal indicating that the radio wave has been received to the switch control unit 6. Thus, the changeover switch 2 is temporarily fixed. If the program processing is performed and the SRC service end notification (step 565) ends, the process proceeds to the switch fixing flag off processing (step 566). If the DSRC service end notification (step 565) does not end, the A / B timer The process proceeds to setting processing (step 560).

  In the A / B timer setting process (step 560), time is set in the A timer 71 and the B timer 72, and the process proceeds to the timer time determination process (step 561). The A timer 71 sets the time during initial communication. The B timer 72 sets a time for each reception. In the A timer time determination process (step 561), when the set time is not a timeout in the A / B timer setting process (step 560), the process proceeds to the B timer time determination process (step 562). The process proceeds to the switch fixing flag off process (step 566). In the B timer time determination process (step 562), if the time set in the A / B timer setting process (step 560) is not timed out, the process proceeds to the switch fixing flag determination process (step 563). The process proceeds to the fixed flag off process (step 566).

In the switch fixing flag off process (step 566), the switch fixing flag is turned OFF, and the process proceeds to the switch cycle switching process (step 551) which is the initial state.
In the switch fixing flag determination process (step 563), the process ends if the flag is ON. If the flag is OFF, the process proceeds to AID determination processing (step 553). In the AID determination process (step 553), the AID is actually analyzed. When the AID is 14, the AID14 switch determination process (step 554) is performed. When the AID is 18, the AID18 switch determination process (step 555) is performed. ).

In the switch determination process for AID14 (step 554), information on which switch is fixed by the switch 2 is sent from the switch control unit 6 at the time of radio wave reception, so the information of the switch control unit 6 is the switch for AID14. In this case, the process proceeds to a switch determination number reset process (step 558). If the information in the switch control unit 6 is a switch for AID18, the process proceeds to a switch determination number process (step 556). Similarly, in the switch determination processing for AID 18 (step 555), when the radio wave is received, information on which switch the change-over switch 2 is fixed is sent from the switch control unit 6; In the case of an AID18 switch, the process proceeds to a switch determination number reset process (step 558), and when the information in the switch control unit 6 is an AID14 switch, the process proceeds to a switch determination number process (step 557).
The switch determination number process (step 556) and the switch determination number process (step 557) count how many times the AID14 switch determination process (step 554) and the AID18 switch determination process (step 555) have passed, respectively. If it is equal to or greater than the set value, the process proceeds to a switch determination number reset process (step 558). If it is less than a certain set value, the process proceeds to a switch determination number increment process (step 559).
In the switch determination number reset process (step 558), the switch determination number of the switch determination number process (step 556) and the switch determination number process (step 557) is set to 0, and the process proceeds to the switch fixing flag ON process (step 564). In the switch determination number increment process (step 559), 1 is added to the switch determined numerical value, and the process proceeds to the switch cycle switching process (step 551) again. In the switch fixing flag ON process (step 564), the switch fixing flag is turned ON to maintain the switch fixing.

  According to the third embodiment, when the time set by the timer control unit has elapsed for the fixed release timing of the on-vehicle antenna changeover switch, when the non-reception communication between the road and vehicle has passed the specified time, the DSRC service is terminated. When information is received by the vehicle-mounted device, and after the change-over switch is unfixed, the two vehicle-mounted antennas that are in the initial state are periodically switched. There is an effect that a DSRC vehicle-mounted device that can be prepared for is obtained.

It is a block diagram which shows the DSRC vehicle-mounted device by Embodiment 1 of this invention. It is a flowchart which shows the process of the data processing part of the DSRC onboard equipment by Embodiment 1 of this invention. It is a block diagram which shows the DSRC onboard equipment by Embodiment 2 of this invention. It is a flowchart which shows the process of the data processing part of the DSRC onboard equipment by Embodiment 2 of this invention. It is a block diagram which shows the DSRC vehicle-mounted device by Embodiment 3 of this invention. It is a flowchart which shows the process of the data processing part of the DSRC onboard equipment by Embodiment 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 In-vehicle antenna 2 Changeover switch 3 RF part 4 Modem part 5 Data processing part 6 Switch control part 11 AID14 antenna 12 AID18 antenna 51 DSRC onboard equipment 52 AID determination means 53 Switch determination means 54 Timer control part 71 A timer 72 B timer

Claims (5)

In a DSRC vehicle-mounted device that is mounted on a vehicle and performs narrow-area communication with a roadside device, the two vehicle-mounted antennas that have different antenna characteristics and perform narrow-band communication with the roadside device, the two vehicle-mounted antennas changeover switch for switching the antenna, before starting communication with the roadside device, the two vehicle-mounted antenna with switched periodically, at the time of communication between the roadside device, the switching to secure the one of the in-vehicle antenna Based on a switch control unit that controls a switch, an AID determination unit that is included in the information transmitted from the roadside device and that indicates an application ID indicating the type of application of the roadside device, and an application ID determination by the AID determination unit , Which of the two on-vehicle antennas is fixed is determined, and the result of the determination is sent to the switch control unit A switch judging means for transmitting,
The switch control unit is temporarily fixed to one vehicle-mounted antenna at the start of communication with the roadside device, and the fixed vehicle-mounted antenna is continuously fixed according to the determination result of the switch determination unit, or the A DSRC vehicle-mounted device that controls the changeover switch so as to periodically switch between two vehicle-mounted antennas . In a DSRC vehicle-mounted device that is mounted on a vehicle and performs narrow-area communication with a roadside device, the two vehicle-mounted antennas that have different antenna characteristics and perform narrow-band communication with the roadside device, the two vehicle-mounted antennas A changeover switch for switching antennas. Before the start of communication with the roadside unit, the two onboard antennas are periodically switched. At the start of communication with the roadside unit, the changeover switch is fixed to one onboard antenna. Based on the switch control unit to be controlled, AID determination means for determining an application ID indicating the type of application of the roadside machine included in the information transmitted from the roadside machine, and the determination of the application ID by the AID determination means, Determine which of the two in-vehicle antennas is to be fixed, and use this switch control A switch judging means for transmitting the parts,
The switch determination unit is a counter unit that counts the number of mismatches when the vehicle-mounted antenna fixed by the switch control unit and the vehicle-mounted antenna that is newly determined by the AID determination unit do not match. has, when the number of mismatches by the counter means exceeds a predetermined value, D SRC OBE you and performs determination of maintaining a fixed vehicle antenna which is fixed by the switch controller. 3. The DSRC in-vehicle device according to claim 1, wherein the two on-vehicle antennas have antenna characteristics suitable for an ETC application and a DSRC application, respectively. The DSRC on-vehicle device according to claim 1 or 3 , wherein the AID determination means determines that the application ID is one of an ETC application and a DSRC application.   A timer control unit for timing the fixed release time after being fixed to one of the two in-vehicle antennas, and the switch control unit is configured to receive the in-vehicle antenna when a time set in the timer control unit has elapsed. The DSRC in-vehicle device according to any one of claims 1 to 4, wherein the control is performed so as to release the fixing of the antenna and periodically switch between the two in-vehicle antennas.

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