JP6358653B2 - Light beacon - Google Patents

Description

  The present invention relates to an optical beacon that performs wireless communication using an optical signal with an in-vehicle device of a traveling vehicle.

As a traffic information service using a road-to-vehicle communication system, so-called VICS (Vehicle Information and Communication System: registered trademark of Road Traffic Information Communication System Center) using optical beacons, radio beacons or FM multiplex broadcasting has already been developed. ing.
Among these, the optical beacon employs optical communication using near infrared rays as a communication medium, and is capable of bidirectional communication with the in-vehicle device. Specifically, uplink information including travel time information between beacons held by the vehicle is transmitted from the in-vehicle device to the infrastructure-side optical beacon.

Conversely, downlink information including traffic jam information, section travel time information, event regulation information, lane notification information, and the like is transmitted from the optical beacon to the in-vehicle device (see, for example, Patent Document 1).
For this reason, the optical beacon includes a light projecting / receiving device (also referred to as a “beacon head”) that projects and receives an optical signal with the vehicle-mounted device. A transmission / reception unit for optical communication having a light-emitting element that is transmitted toward the road and a light-receiving element that receives uplink light transmitted from the vehicle-mounted device is mounted.

In addition, in this type of optical beacon, there is an optical beacon that has a vehicle sensing function that counts the number of passing vehicles of light cars or more in addition to the optical communication function (see, for example, Patent Documents 2 and 3).
In such an optical beacon having a vehicle sensing function, a light emitting element that transmits incident light composed of pulsed light to a downstream side of a downlink region where the in-vehicle device can receive downlink light, and a light receiving element that receives reflected light of the incident light A sensor unit for vehicle detection having the above is further mounted in the housing of the projector / receiver.

JP 2005-268925 A JP 2008-242914 A JP 2011-242835 A

The procedure of road-to-vehicle communication performed while the in-vehicle device passes through the communication area of the optical beacon is generally as follows. Note that different information types are not mixed in one downstream frame.
(A) The optical beacon repeatedly transmits the first downstream frame before receiving the upstream frame. The first downlink frame includes lane notification information in which the identification value of the vehicle ID is not stored, basic information that does not require provision of uplink information, and the like.
(B) The vehicle-mounted device that has received the first downlink frame transmits an uplink frame that stores the vehicle ID of the host vehicle (including information to be provided on the road side).

(C) The optical beacon that has received the upstream frame repeatedly transmits the second downstream frame for a predetermined time (for example, 250 to 350 milliseconds). The second downlink frame includes, in addition to the basic information described above, additional information such as lane notification information in which the acquired identification value of the vehicle ID is stored, special information on condition that provision of predetermined system information is provided, and the like. It is.
(D) When a predetermined time elapses, the optical beacon returns to the step (a) and restarts the repeated transmission of the first downlink frame.

Conventionally, basic information that does not require provision of uplink information includes “simple graphic information” that is information including a simple graphic in which road traffic information is patterned. Therefore, the optical beacon can transmit the simple graphic information in the downlink using the first and second downlink frames regardless of whether the uplink frame is received.
In this case, the in-vehicle device can acquire the simple graphic information without transmitting the uplink frame, and the navigation device mounted on the vehicle can display the road structure including the downstream intersection on the display.

As described above, in the conventional optical beacon, simple graphic information can be included in both the first downlink frame and the second downlink frame.
Therefore, for example, on a road with a narrow width, where the end of the downlink region in the road width direction protrudes from the oncoming lane, a vehicle traveling on the oncoming lane (hereinafter also referred to as an “oncoming vehicle”). There is a possibility that the upstream simple graphic information that is irrelevant to the vehicle is acquired, and the navigation device of the oncoming vehicle displays incorrect road traffic information on the display.

  The present invention has been made in view of such conventional problems, and an object of the present invention is to prevent an oncoming vehicle from performing erroneous navigation using simple graphic information provided by an optical beacon.

(1) An optical beacon according to an aspect of the present invention is an optical beacon that performs wireless communication with an in-vehicle device of a traveling vehicle using an optical signal, and receives an upstream frame composed of the optical signal, and the optical signal. An optical transmission / reception unit that performs transmission of a downstream frame, a communication control unit that does not include simple graphic information in a first downstream frame defined below, and includes simple graphic information in a second downstream frame defined below, Is provided.
First downlink frame: a downlink frame in which transmission is continued at a predetermined transmission period until an uplink frame is received from the in-vehicle device. Second downlink frame: a downlink transmitted for a predetermined time when an uplink frame is received from the in-vehicle device. Frame Simple graphic information: Information that includes simple graphic patterns of road traffic information

  (4) An optical beacon according to another aspect of the present invention is an optical beacon that performs wireless communication using an optical signal with an in-vehicle device of a running vehicle, and receiving an upstream frame composed of the optical signal, and the optical signal An optical transmission / reception unit that performs transmission of a downstream frame, and a communication control unit that performs data lock processing on the first downstream frame that stores the simplified graphic information among the first and second downstream frames, .

  According to the present invention, it is possible to prevent the oncoming vehicle from performing wrong navigation using the simple graphic information provided by the optical beacon.

It is a block diagram which shows schematic structure of a road-vehicle communication system. It is the top view of the road which looked at the installation part of an optical beacon from the top. It is a side view of the road which shows the communication area | region and incident area of an optical beacon. It is a frame block diagram of an uplink frame (uplink information). It is a frame block diagram of a downlink frame (downlink information). It is a table | surface (current specification table | surface) which shows the content for every classification of the provision information included in downlink information. It is a top view of the road which shows the example in which a downward frame is provided to an oncoming vehicle. It is a sequence diagram which shows the procedure of the road-vehicle communication which the optical beacon which concerns on 1st Embodiment performs. It is a table | surface (change table T0) which shows the content for every classification of the provision information included in downlink information. It is a table | surface (change table T1) which shows the content for every classification of the provision information included in downlink information. It is a table | surface (change table T2) which shows the content for every classification of the provision information included in downlink information.

<Outline of Embodiment of the Present Invention>
Hereinafter, an outline of embodiments of the present invention will be listed and described.
(1) The optical beacon of the present embodiment is an optical beacon that performs wireless communication with an on-vehicle device of a running vehicle using an optical signal, and receives an upstream frame composed of the optical signal and a downstream frame composed of the optical signal. And a communication control unit that does not include the simple graphic information defined below in the first downlink frame defined below, and includes the simple graphic information in the second downlink frame defined below. And comprising.

First downlink frame: a downlink frame in which transmission is continued at a predetermined transmission period until an uplink frame is received from the in-vehicle device. Second downlink frame: a downlink transmitted for a predetermined time when an uplink frame is received from the in-vehicle device. Frame Simple graphic information: Information that includes simple graphic patterns of road traffic information

  According to the optical beacon of the present embodiment, the communication control unit performs communication control that does not include the simple graphic information in the first downlink frame and includes the simple graphic information in the second downlink frame. The simple graphic information is transmitted in the downlink by the second downlink frame only when the signal is received.

For this reason, the period during which the simple graphic information is transmitted in the downlink is greatly reduced as compared with the communication control in which the simple graphic information is included in both the first and second downlink frames.
Therefore, the possibility that the oncoming vehicle receives the simple graphic information provided by the optical beacon is reduced, and erroneous navigation in the oncoming vehicle can be prevented.

(2) In the optical beacon according to the present embodiment, the communication control unit defines the lane notification information defined below and the congestion link information defined below, in which the identification value of the vehicle ID is not stored in the storage area of the vehicle ID. Is preferably included in the first downstream frame.
Lane notification information: Information including the storage area of vehicle ID and lane number Traffic jam link information: Information representing the location and degree of traffic jam in link units

The reason is that in the current standard table (see FIG. 6) that defines the content of the information to be included in the downlink information, the “basic information” that the optical beacon unconditionally provides to the vehicle-mounted device includes simple graphic information and Similarly, there may be something that is not preferable when the oncoming vehicle acquires.
On the other hand, if the lane notification information in which the identification value is not stored in the storage area of the vehicle ID is not included in the first downlink frame, the in-vehicle device cannot determine communication establishment with the optical beacon. This is because it needs to be included in the first downstream frame.

  The reason why the traffic jam link information may be included in the first downlink frame is that the traffic jam link information is information that should be provided to the in-vehicle device even if the uplink information is not provided (see “condition” in FIG. 6). 1)), and even if information indicating the position and degree of traffic congestion in link units is provided to the oncoming vehicle, it is unlikely that the oncoming vehicle will be particularly inconvenient. It is because it is thought that it contributes to.

(3) In the optical beacon according to the present embodiment, the communication control unit is configured as follows, in which the identification value of the vehicle ID is not stored in the storage area of the vehicle ID, traffic congestion link information defined below, Only the current position information defined below may be included in the first downlink frame.
Lane information: Information including the storage area of the vehicle ID and lane number Traffic congestion link information: Information indicating the location and degree of traffic congestion in units of links Current location information: Location information indicating the location of the beacon head of the optical beacon

The reason why the current position information may be included in the first downlink frame in addition to the lane notification information and the traffic jam link information in which the identification value of the vehicle ID is not stored is that the current position information is classified as “basic information”. However, even if position information indicating the installation location of the beacon head of the optical beacon is provided to the oncoming vehicle, it is unlikely that the oncoming vehicle will be particularly inconvenient. This is because it is considered that it contributes to the improvement of accuracy.
In addition, there is an in-vehicle device that cannot determine communication establishment with the optical beacon unless the current position information is acquired by the first downlink frame.

(4) The optical beacon of this embodiment viewed from another viewpoint is an optical beacon that performs wireless communication with an in-vehicle device of a running vehicle using an optical signal, and receiving an upstream frame composed of the optical signal, An optical transmission / reception unit for transmitting a downlink frame made of an optical signal, and a communication control for performing data lock processing on the first downlink frame storing the simple graphic information among the first and second downlink frames A section.
Here, “lock processing” of data refers to data processing in which the in-vehicle device cannot extract information from the actual data portion of the downstream frame.

  According to the optical beacon of the present embodiment, the communication control unit performs the above-described locking process on the first downlink frame that stores the simple graphic information. Therefore, the vehicle-mounted device includes the simple graphic information included in the first downlink frame. Cannot be used, and only simple graphic information included in the second downlink frame can be used.

For this reason, compared with the case of the communication control which does not perform said locking process in any of the first and second downlink frames, the period during which the in-vehicle device can acquire the simple graphic information from the optical beacon is greatly reduced.
Therefore, the possibility that the oncoming vehicle acquires the simple graphic information provided by the optical beacon is reduced, and erroneous navigation can be prevented in the oncoming vehicle.

  (5) In the optical beacon according to the present embodiment, the communication control unit stores, for all types of information classified as basic information in which the simple graphic information is included in the classification, the first downlink frame that stores the information. It is preferable to perform the locking process.

  The reason why lock processing is performed on the first downlink frame that stores information of the type classified as basic information is that the optical beacon is defined in the current standard table (see FIG. 6) that defines the contents of provided information to be included in downlink information. This is because “basic information” provided unconditionally to the vehicle-mounted device may be unpreferable if the oncoming vehicle obtains, as with the simple graphic information.

(6) In the optical beacon according to the present embodiment, the communication control unit may include other types of information other than the current position information defined below, among a plurality of types of information classified into basic information included in the simple graphic information. It is preferable to perform the lock process on the first downstream frame storing information.
Current position information: Position information indicating the installation location of the beacon head of the optical beacon

The reason why the first downlink frame storing the current position information is not locked is that the current position information is classified as “basic information” (see FIG. 6), but indicates the installation location of the beacon head of the optical beacon. This is because even if the position information is provided to the oncoming vehicle, it is unlikely that the oncoming vehicle will have any particular inconvenience, and on the contrary, it is considered to contribute to the improvement of the measurement accuracy of the current position of the oncoming vehicle.
In addition, there is an in-vehicle device that cannot determine communication establishment with the optical beacon unless the current position information is acquired by the first downlink frame.

  (7) Contents of “simple graphic information”, “lane notification information”, “congestion link information”, “current position information”, and “basic information” in the optical beacons described in (1) to (6) above. Is compliant with standards related to optical beacons (for example, “Advanced Optical Beacon Near-Infrared AMIS Communication Application Standard Version 1”, etc., which will be described later), that is, substantially the same as the contents defined by the standards. I just need it.

Therefore, in the optical beacon described in the above (1) to (6), for example, when the content of “simple graphic information” itself is not defined, “simple graphic information” is changed to “simple graphic defined by the standard for optical beacons”. It should be interpreted as “information”. The same applies to other information.
That is, “lane notification information” can be read as lane notification information defined in the standard for optical beacons, and “congestion link information” can be read as traffic link information defined in the standards for optical beacons. . The “current position information” can be read as current position information defined in the standard for optical beacons, and the “basic information” can be read as basic information defined in the standards for optical beacons.

<Details of Embodiment of the Present Invention>
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In the present embodiment, an uplink frame transmitted from the in-vehicle device 2 toward the optical beacon 4 may be referred to as “uplink information” or “uplink signal”.
In addition, a downlink frame transmitted from the optical beacon 4 toward the in-vehicle device 2 may be referred to as “downlink information” or “downlink signal”.

[Overall system configuration]
FIG. 1 is a block diagram showing a schematic configuration of a road-vehicle communication system according to the present embodiment. FIG. 2 is a plan view of the road R when the installation portion of the optical beacon 4 of this embodiment is viewed from above.
As shown in FIG. 1, the road-to-vehicle communication system of this embodiment includes an infrastructure-side traffic control system 1 and an in-vehicle device 2 mounted on a vehicle 20 (see FIG. 3) traveling on a road R. .

The traffic control system 1 includes a central device 3 provided in a traffic control room or the like, and a large number of optical beacons (optical vehicle detectors) 4 installed at various locations on the road R. The optical beacon 4 can perform wireless communication with the in-vehicle device 2 by optical communication using near infrared as a communication medium.
The optical beacon 4 includes a beacon controller (communication controller) 7 that performs communication control and the like, and a plurality (four in the example of FIG. 1) of beacon heads (transmit / receive) connected to the sensor interface of the beacon controller 7. 8).

The beacon controller 7 is connected to a communication unit 6 on the infrastructure side, and the communication unit 6 is connected to the central apparatus 3 by a communication line 5 such as a telephone line.
The communication unit 6 can be configured by, for example, a traffic signal controller that controls the color of a signal lamp, an information relay device that performs a relay process of traffic information on the infrastructure side, and the like.

The optical beacon 4 of this embodiment employs a full-duplex communication method. That is, the beacon controller 7 simultaneously performs transmission control in the downlink direction for the light emitting unit 13 for optical communication and reception control in the uplink direction for the light receiving unit 14 for communication.
On the other hand, the in-vehicle device 2 of the present embodiment employs a half-duplex communication method. That is, the below-described vehicle-mounted controller 21 does not simultaneously perform uplink direction transmission control for the optical transmission unit 23 and downlink direction reception control for the optical reception unit 24.

[Overall configuration of optical beacon]
The beacon head 8 of the optical beacon 4 includes a transmission / reception unit (optical transmission / reception unit) 11 for optical communication and a sensor unit 12 for vehicle detection in a housing 31 (see FIGS. 1 and 3).
As described above, in the optical beacon 4 of the present embodiment, the optical communication function and the vehicle detection function are obtained by incorporating the units 11 and 12 for optical communication and vehicle detection into the casing 31 of one beacon head 8, respectively. It has a structure with both.

The transmission / reception unit 11 is an optical transceiver that transmits and receives optical signals to and from the in-vehicle device 2 wirelessly.
As shown in FIG. 1, the transmission / reception unit 11 receives a light emitting unit 13 for optical communication that transmits a downlink light DO (see FIG. 3) and an uplink light UO (see FIG. 3) and converts them into electrical signals. And a light receiving unit 14 for optical communication.

A light emitting unit 13 for optical communication (hereinafter also referred to as “communication light emitting unit 13”) includes a transmission circuit that converts a downstream frame transmitted from the beacon controller 7 into a serial transmission signal having a predetermined transmission rate; A light emitting element made of a light emitting diode (LED) that converts the output transmission signal into an optical signal in a downlink direction.
The light emitting element of the communication light emitting unit 13 sends the downlink light DO, which is a near infrared light signal, obliquely downward toward the upstream side.

The light receiving unit 14 for optical communication (hereinafter also referred to as “communication light receiving unit 14”) amplifies a light receiving element such as a photodiode (PD) and an electric signal output from the light receiving element. A receiving circuit for generating a digital signal.
The light receiving element of the communication light receiving unit 14 receives the uplink light UO, which is a near-infrared optical signal transmitted by the vehicle-mounted device 2 before the beacon head 8, and converts it into an electrical signal. The reception circuit of the communication light receiving unit 14 sends a digital signal generated from the converted electrical signal to the beacon controller 7.

The sensor unit 12 is a light detection sensor for detecting the presence of the vehicle 20 passing almost directly below the beacon head 8 without contact.
As shown in FIG. 1, the sensor unit 12 includes a vehicle sensing light emitting unit 15 that transmits incident light IO (see FIG. 3), and a vehicle that receives reflected light RO (see FIG. 3) and converts it into an electrical signal. And a light receiving unit 16 for sensing.

The vehicle-sensing light-emitting unit 15 (hereinafter also referred to as “sensing light-emitting unit 15”) transmits incident light IO, which is an optical pulse signal having a predetermined cycle, downward.
The vehicle sensing light receiving unit 16 (hereinafter also referred to as “sensing sensing light receiving unit 16”) receives the reflected light RO of the incident light IO on the road R and the vehicle 20, and uses the received reflected light RO as an electrical signal. Convert and send to the beacon controller 7.

The beacon controller 7 includes a computer device having a signal processing unit, a CPU, a memory, and the like, and has a function as a communication control unit that performs communication with the central device 3 and communication between the in-vehicle device 2 and the vehicle according to a predetermined communication interface standard. And a function as a sensing control unit of the vehicle 20.
The beacon controller 7 stores a computer program for communication control and sensing control in a storage device (not shown), and the CPU reads out and executes the program so that the CPU performs the communication control. Functions as a control unit and a sensing control unit.

For example, the beacon controller 7 may include a downlink signal (first downlink frame) including lane notification information in which an identification value of a vehicle ID (hereinafter also referred to as “ID value”) is not stored, or predetermined provision information. Is transmitted to the communication light-emitting unit 13 at a predetermined cycle.
The beacon controller 7 continues to transmit the downlink signal, and receives the uplink signal (uplink frame) including the ID value that the vehicle-mounted device 2 will transmit when receiving the downlink signal. Judgment is made.

  When the beacon controller 7 detects the reception of the uplink signal by the communication light receiving unit 14, the lane notification information storing the ID value and the lane number value extracted from the uplink signal, the provision information for the vehicle 20, and And one or a plurality of downlink signals (second downlink frames) including the generated information are transmitted to the communication light emitting unit 13 for a predetermined time (for example, 250 to 350 ms).

Then, when the predetermined time elapses, the beacon controller 7 restores the content of the provision information included in the downlink signal and waits for reception of the uplink signal from the in-vehicle device 2 of the vehicle 20 that comes next. .
The beacon controller 7 forwards information useful for traffic signal control, such as probe data consisting of a travel locus such as the position and time of the vehicle 20, to the central device 3 if the uplink signal contains information useful for traffic signal control. To do.

The beacon controller 7 always sends the incident light IO of a predetermined wavelength to the sensing light emitting unit 15 at a constant intensity and pulse period, and whether the received light intensity of the reflected light RO received by the sensing light receiving unit 16 is equal to or greater than a threshold value. The presence of the vehicle 20 is sensed depending on whether or not.
This threshold value is not limited to a fixed value, and may vary depending on, for example, a follow-up process according to the received light intensity of the reflected light RO. That is, the beacon controller 7 generates a sensing signal of the vehicle 20 and transmits the sensing signal to the central device 3 when the light receiving intensity of the reflected light RO that is equal to or greater than the threshold value is detected in the sensing light receiving unit 16.

[Optical beacon installation status]
As shown in FIG. 2, the optical beacon 4 of the present embodiment is installed on a road R having a plurality (four in the illustrated example) of lanes R1 to R4 in the same direction.
The optical beacon 4 includes a plurality of the beacon heads 8 provided corresponding to the respective lanes R1 to R4, and one beacon controller 7 that is a communication control unit that collectively controls these beacon heads 8. I have.

The beacon controller 7 is installed on a support column 17 erected on the left side of the road R. Each beacon head 8 is attached to an erection bar (beam member) 18 that is horizontally installed from the support column 17 to the road R side, and is disposed immediately above each lane R1 to R4 of the road R.
The communication light emitting unit 13 of each beacon head 8 emits the downlink light DO toward the upstream side in the vehicle traveling direction from directly below the own device. Thereby, the communication area A for performing road-to-vehicle communication with the in-vehicle device 2 is set on the upstream side of the beacon head 8.

  Further, the sensing light emitting unit 15 of each beacon head 8 emits the incident light IO directly below the own device. Thereby, the incident area B, which is the sensing area of the vehicle 20 passing through the predetermined lanes R1 to R4 of the road R, is set almost directly below the beacon head 8.

[Communication area and incident area of optical beacons]
FIG. 3 is a side view of the road R showing the communication area A and the incident area B of the optical beacon 4.
As shown in FIG. 3, the communication area A of the transmission / reception unit 11 includes a downlink area DA (solid hatched portion) that is a receivable range of the downlink light DO by the in-vehicle device 2 and an uplink light UO by the beacon head 8. And an uplink area UA (dashed hatched portion), which is a light receiving range.

According to the UTMS (Universal Traffic Management System) Association “Optical Vehicle Sensor Near-Infrared Interface Standard Version 2” (hereinafter referred to as “Old Interface Standard”) formulated on August 3, 2001. The upstream ends c0 of the areas DA and UA are supposed to coincide with each other.
Further, the standard values (in the case of ordinary roads) of the upstream and downstream end positions of the areas DA and UA in the old interface standard are exemplified as follows. However, this standard value is a value when the height H from the road surface is 1.0 m and the upstream direction from the position immediately below the light emitter / receiver 8 (origin O) is a positive number.

Downstream area DA downstream end position a0: +1.3 m
Downstream end position b0 of the uplink area UA: a0 + 2.1 m (= 3.4 m)
Upstream end position c0 of both areas DA and UA: b0 + 1.6 m (= 5.0 m)

The incident area B of the sensor unit 12 is an irradiation range of the incident light IO on which the sensing light emitting unit 15 enters the road R.
The center of the incident area B in the road width direction is at a position substantially equal to the center of the lanes R1 to R4 corresponding to the beacon head 8 in the road width direction. The emission direction V1 of the incident light IO is normally directed upstream (plus side) by a predetermined angle α (for example, 4.5 °) with respect to the vertical direction, but is downstream by a predetermined angle with respect to the vertical direction. It may be directed to the side (minus side).

[Configuration of in-vehicle device]
As shown in FIG. 3, the in-vehicle device 2 of this embodiment includes an in-vehicle controller 21 and an in-vehicle head 22. An optical transmitter 23 and an optical receiver 24 are accommodated in the in-vehicle head 22.
Among these, the optical transmission unit 23 has a light emitting element that emits uplink light UO (uplink direction optical signal) made of near infrared rays, and the optical reception unit 24 is a near infrared ray transmitted to the downlink area DA. And a light receiving element that receives downlink light UO (an optical signal in the downlink direction).

The optical transmission unit 23 is a light emitting circuit that converts an upstream frame output from the in-vehicle controller 21 into a serial transmission signal having a predetermined transmission rate, and converts the output transmission signal into an optical signal in the uplink direction. And a light emitting element made of a diode or the like.
The optical receiver 24 includes a light receiving element such as a photodiode that photoelectrically converts an optical signal in the downlink direction and outputs an electric signal, and a receiving circuit that amplifies the output electric signal and generates a digital received signal. Have

According to the old interface standard of the UTMS Association, the transmission speed of the uplink optical UO transmitted by the optical transmission unit 23 of the in-vehicle device 2 is 64 kbps, and the transmission of the downlink optical DO received by the optical reception unit 24 of the in-vehicle device 2 is performed. The speed is 1024 kbps.
The UTMS Association's “Advanced Optical Beacon Near-Infrared Interface Standard Version 2” (hereinafter referred to as “New Interface Standard”) formulated on May 7, 2013 has two types of multi-channels with high and low uplink speeds. The rate is changed (low speed is 64 kbps and high speed is 256 kbps).

The optical beacon 4 and the in-vehicle device 2 according to the present embodiment may conform to any of the old interface standard and the new interface standard described above.
The optical beacon 4 according to the new interface standard is a multi-rate compatible optical beacon (hereinafter also referred to as “new optical beacon”) capable of receiving a conventional low-speed uplink reception and a new high-speed uplink reception. The in-vehicle device 2 conforming to the new interface standard is a multi-rate in-vehicle device (hereinafter also referred to as “new in-vehicle device”) that can perform conventional low-speed uplink transmission and new high-speed uplink transmission. is there.

In the following description, when it is necessary to distinguish between old and new optical beacons 4, the new optical beacon may be described as “new optical beacon 4A” and the old optical beacon may be described as “old optical beacon 4B”. .
When it is necessary to distinguish between the new and old of the vehicle-mounted device 2, the new vehicle-mounted device may be described as “new vehicle-mounted device 2A” and the old vehicle-mounted device may be described as “old vehicle-mounted device 2B”.

The in-vehicle controller 21 includes a computer device having a signal processing unit, a CPU, a memory, and the like, and has a function as a communication control unit that performs road-to-vehicle communication with the optical beacon 4.
The in-vehicle controller 21 stores a computer program for communication control in a storage device (not shown), and the CPU reads and executes the program, so that the CPU functions as the communication control unit. To do.

The in-vehicle controller 21 generates traveling data of the host vehicle (for example, probe information that is traveling locus data in which passing positions and passing times are arranged in time series) as uplink data, and uploads it to the optical transmitter 23. It also has a function to transmit a link.
In this case, if the uplink speed is increased as in the new interface standard, more probe information (longer road sections that record the travel trajectory, higher recording density of passing positions and passing times in the same road section) Information can be transmitted.

In addition, the vehicle-mounted controller 21 of this embodiment may have a circuit configuration in which a simple control unit including an ASIC (Application Specific Integrated Circuit) is provided separately from the main body control unit including the CPU.
For example, when the optical receiving unit 24 receives any downlink frame, the simple control unit includes only one uplink frame (conventional uplink frame having a transmission rate of 64 kbps) including the vehicle ID of the host vehicle, and the optical transmission unit 23. Has the function of transmitting to the uplink.

As shown in FIG. 3, a navigation device 25 is mounted on the vehicle 20. The navigation device 25 includes a route search unit that searches for an optimal route when traveling to a destination, an operation unit for a passenger to input to the route search unit, and an optimal route that is a calculation result using an image or voice. A display and a speaker for guiding the user.
In general, the route search unit calculates a minimum cost route that minimizes the link cost by a specific route search logic. As the route search logic, for example, the Dijkstra method or the potential method is used.

The navigation device 25 has a time synchronization function for acquiring the current time from the GPS signal, a position detection function for measuring the current position (latitude, longitude, and altitude) of the host vehicle from the GPS signal, and an azimuth and angular velocity of the host vehicle by the direction sensor. It has an orientation detection function that measures
The navigation device 25 also includes a storage device (not shown) in which road map data is stored. The road map data is used to map match the position information of the host vehicle during the search process by the route search unit.

The in-vehicle controller 21 includes information related to traffic regulation (for example, “event regulation link information” in FIG. 6) and information useful for navigation (for example, “simple graphic information” in FIG. 6) in the downlink signal. If so, the information is output to the navigation device 25.
For example, when the navigation device 25 acquires simple graphic information from the in-vehicle controller 21, the navigation device 25 displays the graphic information on the display. Thereby, the passenger of the vehicle 20 can visually recognize a simple image or the like indicating road traffic information in the vicinity of the intersection on the downstream side of the beacon head 8 in advance.

[Frame structure of upstream frame]
FIG. 4 is a frame configuration diagram of an uplink frame (uplink information).
As shown in FIG. 4, in the upstream frame storage area, in order from the beginning, a transmission control unit for synchronization (hereinafter referred to as “synchronizing unit”) for synchronizing with the receiving side, a header unit, and an actual data unit. And a CRC (Cyclic Redundancy Check) transmission control unit (hereinafter referred to as “CRC unit”).

In the upstream frame, 1 byte is assigned to the synchronization part, 10 bytes are assigned to the header part, 59 bytes at maximum are assigned to the real data part, and 4 bytes (1 byte idle part + 2 bytes CRC + 1 byte) are assigned to the CRC part. Of the last synchronization part).
The header portion of the upstream frame includes storage areas such as “number of subsystem key information”, “vehicle ID”, “vehicle equipment type”, “information type”, and “last frame flag”.

In the “number of subsystem key information” (hereinafter sometimes abbreviated as “number of information”), the number of “subsystem key information” stored in order from the top of the actual data portion is stored.
That is, when the number of information is zero, “subsystem key information” is not included in the actual data portion, and when the number of information is “1”, one “subsystem key information” is included in the actual data portion. When the number of information is “n”, n “subsystem key information” is included in the actual data part.

The above-mentioned “subsystem key information” indicates that the optical beacon 4 is a downlink of a public vehicle priority system (PTPS), a vehicle operation management system (MOCS), a field express support system (FAST), and a safe driving support system (DSSS). This is key information for selecting additional information.
The in-vehicle device 2 determines the contents of “subsystem key information” and “subsystem key information” according to which system of the UTMS standard the host vehicle is compatible with.

For example, the in-vehicle device 2 sets the value of the “number of subsystem key information” in the header part to “1” when the host vehicle corresponds to one system of the UTMS standard, and follows the standard of the one system. The “subsystem key information (1)” of the contents is stored in the actual data part.
In addition, when the host vehicle is compatible with two systems of the UTMS standard, the in-vehicle device 2 sets the value of the “number of subsystem key information” in the header part to “2”, and sets the standard of the two systems respectively. The “subsystem key information (1)” and “subsystem key information (2)” having the contents are stored in the actual data part.

  The data format of the “subsystem key information” is different depending on the standard of each system, so the details are omitted. For example, in the case of a safe driving support system (DSSS), the brake state, the turn signal state, the hazard state, Information such as vehicle speed, traveling direction, acceleration / deceleration, and accelerator pedal position is included.

On the other hand, the optical beacon 4 determines which system included in the in-vehicle device 2 is included in the UTMS standard according to the type of “subsystem key information” included in the uplink information, and conforms to the standard of the system. The provided information is stored in the downlink frame and transmitted in the downlink. This provision information is called “special information” (see FIG. 6) in the standard.
In this way, the optical beacon 4 determines the type of “special information” to be included in the downlink information after uplink reception based on the type of “subsystem key information”.

“Vehicle ID” is an area for storing a vehicle ID identification value (which may be a numerical value or a symbol) generated by the vehicle-mounted device 2 itself or automatically generated by the optical beacon 4 and notified to the vehicle-mounted device 2. . The in-vehicle device 2 stores the value of the vehicle ID stored at the time of uplink transmission in the vehicle ID of the header portion of the uplink frame.
“In-vehicle device type” is an area in which the type of the in-vehicle device 2 is stored. “Information type” is an area for storing the type of uplink information. In the new interface standard, the values of these areas indicate whether the uplink transmission subject is new or old, and whether the uplink information is high speed or low speed.

Specifically, when transmitting a low-speed uplink frame, the new in-vehicle device 2A stores a predetermined value (for example, “6”) indicating the new in-vehicle device 2A in the “in-vehicle device type” and the “information type”. A predetermined value (for example, “1”) is stored in.
Further, when transmitting a high-speed uplink frame, the new in-vehicle device 2A stores a predetermined value (for example, “6”) indicating the new in-vehicle device 2A in the “in-vehicle device type” and a predetermined value in the “information type”. (For example, “4”) is stored.

Accordingly, the new optical beacon 4A can determine that the received frame is a low-speed frame from the new in-vehicle device 2A when the in-vehicle device type value of the received upstream frame is “6” and the information type value is “1”. When the value of the in-vehicle device type of the uplink frame is “6” and the value of the information type is “4”, it can be determined that the high-speed frame is from the new in-vehicle device 2A.
In the case of the old vehicle-mounted device 2B, since the value of the vehicle-mounted device type is set to other than “6”, the new light beacon 4A receives an uplink frame having a value of “vehicle-mounted device type” other than “6”. It can be determined that the communication partner is the old vehicle-mounted device 2B that does not support high-speed uplink transmission.

The “last frame flag” is a storage for indicating which of the uplink frames is the final frame when the in-vehicle device 2 (new or old) transmits an uplink frame group including a plurality of uplink frames. It is an area.
That is, the in-vehicle device 2 stores a predetermined flag value (for example, “1”) only in the “final frame flag” of the last frame among the plurality of uplink frames constituting the uplink frame group, and other uplink frames Does not store the flag value.

[Frame structure of downstream frame]
FIG. 5 is a frame configuration diagram of a downlink frame (downlink information).
As shown in FIG. 5, the downlink frame storage area also includes a synchronization part, a header part, an actual data part, and a CRC part in order from the top, as in the case of the frame structure of the upstream frame (FIG. 4). .

In the downstream frame, 1 byte is allocated to the synchronization section, 5 bytes are allocated to the header section, 123 bytes are allocated to the real data section, and 4 bytes are allocated to the CRC section (1 byte idle section + 2 bytes CRC + 1 byte final). Synchronous part) is assigned.
The type of information provided to the in-vehicle device 2 included in the actual data portion of the downstream frame may change before and after the optical beacon 4 receives the upstream frame from the in-vehicle device 2.

That is, the optical beacon 4 can switch the content of the information provided to the in-vehicle device 2 before and after receiving the uplink frame.
Specifically, the optical beacon 4 transmits a downlink frame (hereinafter referred to as a “first downlink frame”) 2013 that is downlink-transmitted before receiving an uplink frame from the in-vehicle device 2 (before uplink reception). Provision of uplink information in “Advanced Optical Beacon Near-Infrared AMIS Communication Application Standard Version 1” (hereinafter referred to as “Communication Application Standard (Version 1)”), which was formulated on May 7, 1980 It is possible to include information (such as “basic information” in FIG. 6) that is defined as not satisfying the condition in the actual data part.

  In addition, the optical beacon 4 has a communication application standard (hereinafter referred to as “second downlink frame”) in a downlink frame (hereinafter referred to as a “second downlink frame”) transmitted in downlink after receiving the uplink frame from the in-vehicle device 2 (after receiving the uplink). In addition to the information specified in the version 1) that the provision of uplink information is not a condition (such as “basic information” in FIG. 6), the communication application standard (version 1) specifies that the provision of uplink information is a condition. The information (such as “additional information” in FIG. 6) can also be included in the actual data part.

The optical beacon 4 provides the provision information to the in-vehicle device 2 by one downlink frame when the provision information of the single information type to the in-vehicle device 2 fits in the capacity of the actual data part (123 bytes).
The optical beacon 4 is divided into a plurality of downlink frames (downstream frame groups) when the provision information of the single information type to the in-vehicle device 2 does not fit in the capacity of the actual data part (123 bytes), The provided information is provided to the in-vehicle device 2. Therefore, different information types are not mixed in one downstream frame.

As shown in FIG. 5, examples of the provision information included in the first downlink frame include, for example, “lane notification information” (where the vehicle ID identification value is not stored), “current position information”, and the like. There is. The “lane notification information” is information for notifying the lane number where the vehicle 20 travels, and the “current position information” is the position information (latitude and longitude) of the installation location of the beacon head 8.
The storage area of “lane notification information” includes “vehicle ID”, “lane number”, and “beacon identification flag”. The optical beacon 4 does not store the identification value in the “vehicle ID” in the lane notification information included in the downlink frame before uplink reception.

When the optical beacon 4 receives the upstream frame including the identification value (ID value) of the vehicle ID from the in-vehicle device 2, the optical beacon 4 stores the acquired ID value in the “vehicle ID” of the lane notification information (hereinafter, this downstream frame). Is also referred to as a “turnback frame”), and the generated return frames are downlink transmitted at predetermined intervals.
Therefore, the in-vehicle device 2 can determine communication establishment with the optical beacon 4 based on whether or not the ID value of the host vehicle is included in the received lane notification information of the return frame.

In addition, the optical beacon 4 writes the lane number value corresponding to the beacon head 8 that acquired the uplink information in the “lane number” of the lane notification information included in the return frame.
Therefore, the in-vehicle device 2 can determine which lane the host vehicle is traveling from the lane number value included in the received lane notification information of the return frame.

The “beacon identification flag” is a storage area indicating whether or not the own device supports high-speed uplink reception.
When the optical beacon 4 is the new optical beacon 4A, the optical beacon 4 stores a predetermined flag value (for example, “01”) in the “beacon identification flag” of the downstream frame. The other value (for example, “00”) is stored in the “beacon identification flag” of the downstream frame.

  Therefore, the new in-vehicle device 2A determines whether the communication beacon optical beacon 4 is the new optical beacon 4A or the old optical beacon 4B based on the value of the “beacon identification flag” included in the “lane notification information” of the downstream frame. Can be determined.

The downlink frame group that is repeatedly transmitted by the transmission / reception unit 11 of the optical beacon 4 after uplink reception is composed of 1 to 80 downlink frames, and in the case of the old interface standard, the transmission time of the repeated transmission is 250 ms. .
Further, the downlink frame is composed of an arbitrary number of frames corresponding to the amount of data to be transmitted in the downlink direction, and is repeatedly transmitted within the above-described transmittable time range, and the downlink frame transmission period is about 1 ms.

Therefore, for example, when one significant data (provided information) is constituted by three downstream frames, the transmission cycle is about 3 ms, so that the data is about 80 times within a predetermined transmittable time (250 ms). It will be sent repeatedly.
However, in the new interface standard optical beacon 4A, the downlink area DA is expanded to the vicinity immediately below the beacon head 8, so the number of repeated transmissions of a downlink frame group composed of 1 to 80 downlink frames is increased. Can be made.

  As shown in FIG. 5, examples of the provision information included in the second downlink frame include “route signal information” and “travel speed link information”. The contents of these information will be described later.

[Specific examples of provided information]
FIG. 6 is a table showing the contents for each type of provision information included in the downlink information.
This table is derived from the “downlink information provision information type” table (hereinafter referred to as “current standard table”) defined in the aforementioned communication application standard (version 1), “classification”, “information type”, It is a table created by extracting the columns “Summary (Purpose)” and “Provision conditions”.
As shown in the “classification” column of FIG. 6, the provision information included in the downlink information is roughly divided into “general information” and “special information”. The general information is further classified into “basic information” and “additional information”, and the additional information is further classified into “common information” and “individual information”.

“General information” refers to information provided to general users (other than specific users) and specific users.
“Basic information” refers to information provided to all users regardless of the provision of uplink information. That is, it is information that can be provided to the in-vehicle device 2 without providing the uplink information from the in-vehicle device 2 as a condition.

“Additional information” refers to information that is provided to the user depending on the presence or absence of uplink information. That is, the information can be provided to the in-vehicle device 2 on condition that the uplink information is provided from the in-vehicle device 2.
“Common information” refers to additional information having the same (unique) content for all information provision target users.

“Individual information” refers to additional information (information provided from an optical beacon that varies depending on the request from each near-infrared type in-vehicle communication device) that is individually different for the information provision target user. Say.
“Special information” refers to information to be provided to a specific user (qualified person) approved by a traffic manager in advance.

  As shown in the “Information Type” column of FIG. 6, “Basic Information” includes “Current Location Information”, “Connection Network Information”, “Emergency Message”, “Caution Warning Information”, “Message Information”, “ 12 types of "simple graphic information 1", "simple graphic information 2", "parking lot information", "event regulation link information", "failure information", "section travel time information", and "center network failure notification information" Contains information. The contents of these pieces of information are as described in the “Summary” column of FIG.

Since the above 12 types of information are included in the “basic information”, the “providing condition” column in FIG. 6 is “none”. That is, since these 12 types of information do not require the provision of uplink information from the vehicle-mounted device 2, the optical beacon 4 according to the current standard table is based on both the first and second downlink frames. Can be transmitted in the downlink.
Of the information included in the basic information, “current position information” is specifically position information (latitude and longitude) of the installation location of the beacon head 8.

“Simple graphic information 1” is variable information among information including simple figures and characters in which road traffic information and the like are patterned. The variable information is information that displays, for example, red or letters on a traffic jam road.
“Simple graphic information 2” is fixed information among information composed of simple figures and characters in which road traffic information and the like are patterned. The fixed information is information such as road alignment and destination directions, for example.

The simple graphic information 1 and simple graphic information 2 are separated by considering that traffic conditions such as traffic jams are likely to fluctuate depending on the day of the week and the time of day, and separating the variable information from the fixed information. This is to reduce the amount of data included in the information.
In the present embodiment, when simply referred to as “simple graphic information”, it means that at least “simple graphic information 2” is included, and “simple graphic information 1” may be included or not included. To do.

  The “basic information” in FIG. 6 does not guarantee that the optical beacon 4 always provides twelve types of information classified as such. Therefore, depending on the situation such as the installation location of the optical beacon 4, there are cases where only less than 12 types of information are provided.

As shown in the “Information Type” column of FIG. 6, “Common Information” includes “Congestion Link Information”, “Congestion / Travel Time Link Information”, “Travel Speed Link Information”, and “Route Signal Information”. There are four types of information. The specific contents of these pieces of information are as described in the “Summary” column of FIG.
For example, among the information included in the common information, “traffic congestion link information” is information that represents the position and degree of the traffic congestion in units of links. “Congestion / travel time link information” is information obtained by adding travel time information of the link to the link included in the congestion link information.

Among the above four types of information, “congestion link information” is “condition 1” in the “providing condition” column of FIG. 6 (= when the in-vehicle device 2 does not provide uplink information). . In the “congestion / travel time link information”, the “providing condition” column of FIG. 6 is “condition 2” (= when the in-vehicle device 2 provides the uplink information).
Therefore, the optical beacon 4 according to the current standard table provides the traffic jam link information to the in-vehicle device 2 before receiving the uplink, and provides the traffic jam / travel time link information to the in-vehicle device 2 after receiving the uplink.

Specifically, the optical beacon 4 according to the current standard table includes “congestion link information” in the first downlink frame transmitted in downlink before uplink reception.
In addition, when the optical beacon 4 according to the current standard table receives an uplink frame uplink thereafter, the optical beacon 4 generates “congestion / travel time link information” including travel time information in the traffic jam link information. The downlink transmission is included in the second downlink frame.

“Travel speed link information” has “Condition 3” in FIG. 6 as “Condition 3” (= when the in-vehicle device 2 provides uplink information of travel time measurement detailed information). “Travel time measurement detailed information” refers to detailed travel time information generated by pairing the narrow link number of the road through which the vehicle 20 has passed in the past with the timer value possessed by the in-vehicle device 2. Say.
Accordingly, the optical beacon 4 according to the current standard table includes the “travel speed link information” in the second downlink frame and transmits the downlink.

Specifically, the optical beacon 4 according to the current standard table does not include “travel speed link information” in the first downlink frame before uplink reception.
In addition, when the optical beacon 4 according to the current standard table receives an uplink frame including the travel time measurement detailed information in the uplink thereafter, the optical beacon 4 includes the “travel speed link information” in the second downlink frame and transmits the downlink. .

In the “route signal information”, the “providing condition” column of FIG. 6 is “condition 4” (= when the in-vehicle device 2 provides the uplink information of the vehicle measurement information 2). “Vehicle measurement information 2” refers to information measured based on the trajectory points for a predetermined time and a predetermined distance in the probe data of the vehicle 20.
Therefore, the optical beacon 4 according to the current standard table provides the “route signal information” to the in-vehicle device 2 after receiving the uplink.

Specifically, the optical beacon 4 according to the current standard table does not include “route signal information” in the first downlink frame before uplink reception.
In addition, when the optical beacon 4 according to the current standard table receives an uplink frame including the vehicle measurement information 2 composed of the above probe data, the optical beacon 4 includes the “route signal information” in the second downlink frame and the downlink. Send.

As shown in the column “Information Type” in FIG. 6, “Individual information” includes only “lane notification information”. The lane notification information is information for providing a lane number to the vehicle 20.
In the “lane notification information”, the “providing condition” column in FIG. 6 is “none”. Therefore, the optical beacon 4 according to the current standard table can transmit the lane notification information in the downlink using both the first and second downlink frames.

However, the lane notification information is also additional information (individual information) whose contents are different for each user, and the contents change depending on before and after uplink reception.
Specifically, the optical beacon 4 according to the current standard table includes lane notification information in which the ID value and the lane number value are not stored in the first downlink frame before uplink reception. Moreover, the optical beacon 4 according to the current specification table stores the ID value extracted from the uplink frame and the lane number value corresponding to the beacon head 8 that acquired the uplink frame in the second downlink frame after receiving the uplink. Include lane notification information.

As shown in the column “Information Type” in FIG. 6, “specific information” means information defined for each specific user.
The special information includes, for example, information compliant with system standards such as a vehicle operation management system (MOCS), a public vehicle priority system (PTPS), and a safe driving support system (DSSS).

The optical beacon 4 according to the current standard table conforms to the standard of each system on condition that an upstream frame including “subsystem key information” (see FIG. 4) conforming to any of the above system standards is received. The second downlink frame including the provision information is downlink transmitted.
In this way, the special information is provided to the in-vehicle device 2 by the second downlink frame on condition that the in-vehicle device 2 provides uplink information (= subsystem key information).

[Problems of optical beacons related to oncoming vehicles]
FIG. 7 is a plan view of the road R showing an example in which a descending frame is provided to the oncoming vehicle 20B.
In the example shown in FIG. 7, it is assumed that the east side of the intersection J is “X direction”, the west side of the intersection J is “Y direction”, the south side of the intersection J is “Z direction”, and the north side of the intersection J is “Q direction”. To do. In addition, place names such as Tokyo and Osaka are entered in X, Y, Z, and Q attached in front of each direction.

Also, the up road RL1 flowing into the intersection J from the west side (Y direction) and the down road RL2 flowing out from the intersection J to the west side (Y direction) are separated by a yellow line without a median. Roads RL1 and RL2 are each assumed to be two lanes on one side.
Further, the beacon head 8 of the optical beacon 4 is installed on an outflow path of an intersection (not shown) adjacent to the west side (Y direction) of the intersection J on the up road RL1, and the vehicle 20 (hereinafter referred to as the road 20) (which will be described below). , “Communication vehicle 20 </ b> A”) communicates with the optical beacon 4 in the communication area A of the beacon head 8.

As described above, in the current standard table, simple graphic information is classified as “basic information” (see FIG. 6) that does not require provision of uplink information by the in-vehicle device 2.
Therefore, the in-vehicle device 2 of the communication vehicle 20 </ b> A can acquire simple graphic information on the east side (X direction) from the optical beacon 4 without uplink transmission of the uplink frame to the optical beacon 4. For this reason, the navigation device 25 of the communication vehicle 20A can display a simple graphic of the road portion corresponding to the intersection J illustrated on the upper navigation screen of FIG. 7 on the display.

By the way, in the old interface standard and the new interface standard, the road width direction range of the downlink area DA (FIG. 3) is a predetermined value (= 4. 4) at a position of ± 1.75 m in the left-right direction with the center of the lane as the origin. 5 μW / cm ² ) or more is defined as a range in which a downlink light amount can be obtained.
Accordingly, in the roads RL1 and RL2 that face each other without a median, for example, when the right lane width of the up road RL1 is relatively small, the down road RL2 in which a part of the communication area A of the beacon head 8 is the oncoming lane. There is a risk of protruding into the right lane.

In the current standard table of the communication application standard (version 1), since the simple graphic information belongs to “basic information” that does not require uplink reception, the optical beacon 4 according to the current standard table is a vehicle traveling on the down road RL1. Even during a period in which 20 does not pass through the communication area A, the first downlink frame including the simple graphic information must be transmitted.
For this reason, the vehicle 20 traveling in the right lane of the down road RL2 toward the west side (Y direction) (hereinafter, referred to as “oncoming vehicle 20B”) is simplified graphic information from the light beacon 4 to the east side (X direction). There is a possibility of receiving a first downlink frame including

  In this case, for example, as illustrated in the lower navigation screen of FIG. 7, the navigation device 25 of the oncoming vehicle 20B displays on the display a simple figure of the east side (X direction) road portion on which the oncoming vehicle 20B has already passed. Thus, erroneous navigation is performed for the passenger of the oncoming vehicle 20B.

[First embodiment: Solution by changing provision conditions]
Therefore, in the first embodiment, the oncoming vehicle 20B acquires simple graphic information irrelevant to the own vehicle by enabling the optical beacon 4 to execute communication control that does not include simple graphic information in the first downlink frame. The possibility is reduced, thereby solving the above-mentioned problems.
Such communication control can be achieved by changing the downlink information provision condition of the current standard table (FIG. 6) as shown in the table shown in FIG. 9, for example.

FIG. 9 is a table showing the contents for each type of provided information included in the downlink information, which is applied to the optical beacon 4 of the first embodiment.
Specifically, the table shown in FIG. 9 (hereinafter referred to as “change table T0”) is used to enable the optical beacon 4 to execute communication control that does not include simple graphic information in the first downlink frame. It is the table | surface which added the change to the standard table | surface (FIG. 6). The hatched portion in FIG. 9 is the information type and provision condition portion obtained by changing the current standard table (FIG. 6).

As apparent from the comparison between FIG. 6 and FIG. 9, in the change table T0 of FIG. 9, the contents of “provided conditions” regarding “simple graphic information 1” and “simple graphic information 2” are changed from “none” to “conditions”. 2 ”(= when the in-vehicle device 2 provides uplink information).
Therefore, the optical beacon 4 according to the present embodiment according to the change table T0 does not provide the simple graphic information (= generic name of the simple graphic information 1 and 2) to the in-vehicle device 2 in the first downlink frame, and does not provide the uplink frame (uplink). The data content of the information is provided to the in-vehicle device 2 by the second downlink frame on the condition that reception is not required).

Hereinafter, road-to-vehicle communication performed by the optical beacon 4 according to the present embodiment according to the change table T0 with the vehicle-mounted device 2 will be described with reference to FIG.
FIG. 8 is a sequence diagram illustrating a procedure of road-to-vehicle communication performed by the optical beacon 4 according to the first embodiment.
In FIG. 8, “with vehicle ID” means that the identification value of the vehicle ID is stored in a predetermined storage area of the frame, and “without vehicle ID” means that the identification value of the vehicle ID is that of the frame. It means that it is not stored in a predetermined storage area.

  A down frame with a white circle indicates a down frame including lane notification information without a vehicle ID, an up frame with a black circle indicates an up frame including a header portion with a vehicle ID, and a down frame with a black circle. The frame indicates a downlink frame (turned frame) including lane notification information with a vehicle ID.

  “DL1” means “first downlink frame” transmitted by the optical beacon 4 before uplink reception, and “UL1” transmits uplink while the vehicle-mounted device 2 passes through the communication area A. “DL2” means “second downlink frame” transmitted by the optical beacon 4 after receiving uplink.

  In the following description of road-to-vehicle communication, the main operating entities are the optical beacon 4 and the in-vehicle device 2, but actual communication control is performed by the beacon controller (communication control unit) 7 of the optical beacon 4 and the in-vehicle device 2. The in-vehicle controller (communication control unit) 21 executes.

As shown in FIG. 8, the optical beacon 4 continues to transmit the first downlink frame DL1 at a predetermined transmission cycle from each beacon head 8 provided for each of the lanes R1 to R4.
The optical beacon 4 of this embodiment operates based on the change table T0 (FIG. 9). Therefore, the optical beacon 4 employs traffic congestion link information among common information and lane notification information without a vehicle ID, basic information other than simple graphic information, and common information as provided information included in the first downlink frame DL1. Thus, the optical beacon 4 of this embodiment does not include simple graphic information in the first downlink frame DL1 before receiving the uplink frame UL1 from the in-vehicle device 2.

When the vehicle 20 enters the downlink area DA, the vehicle-mounted device 2 includes the first downlink frame DL1 including lane notification information without a vehicle ID, or the first downlink frame DL1 including basic information other than simple graphic information. Receive.
As a result, the vehicle-mounted device 2 senses that the vehicle 20 on which the vehicle-mounted device 2 is mounted enters the communication area A of the optical beacon 4.

At this time, the in-vehicle device 2 generates an uplink frame UL1 (hereinafter also referred to as “ID storage frame”) in which the ID value of the host vehicle is stored in the header portion, and switches the communication of the host device from reception to transmission once. Then, the generated ID storage frame is uplink transmitted, and then the communication of the own device is returned from transmission to reception.
When there is information to be provided to the optical beacon 4 such as travel time information, the in-vehicle device 2 stores the information in the actual data portion of the ID storage frame.

When the optical beacon 4 properly receives the ID storage frame through the CRC check of the received frame, etc., the provided beacon 4 determines the provided information provided after receiving the uplink within 10 milliseconds at the latest, and includes the determined provided information. Repetitive transmission of the downlink frame DL2 is started.
In the second downlink frame DL2, in addition to a plurality of folded frames (downlink frames DL2 with black circles) repeatedly transmitted at the head portion, common information (excluding traffic jam link information) and special information repeatedly transmitted thereafter are also included. And basic information.

That is, the second downlink frame DL2 other than the return frame is the second downlink frame DL2 in which common information (excluding traffic jam link information), special information, or basic information is stored in the actual data part.
In the change table T0 (FIG. 9), the provision condition of the simple graphic information is “condition 2” (= when the in-vehicle device 2 provides the uplink information). Although it is not transmitted by the frame DL1, it is transmitted by the second downlink frame DL2.

The repeated transmission of the second downlink frame DL2 is repeated as much as possible within a predetermined time (for example, 250 to 350 milliseconds).
As shown in FIG. 8, the folded frame (downlink frame DL2 with a black circle) is one of a series of downlink frames DL2 (five downlink frames DL2 in the illustrated example) that are repeatedly transmitted during a predetermined transmission period. It is repeatedly transmitted only at the beginning of a series of downstream frames DL2 (every 5 frames in the figure).

In the old interface standard and the new interface standard, one type of provision information can be stored in up to 80 downlink frames DL2. For this reason, the return frame (the downlink frame DL2 with a black circle) is downlink transmitted at a rate of one in 80 frames in the case of the least frequency.
The in-vehicle device 2 receives a plurality of second downlink frames DL2 from the optical beacon 4, and includes some of the received second downlink frames DL2 including lane notification information in which the vehicle ID of the host vehicle is written It is determined whether or not.

When the determination result is affirmative, the in-vehicle device 2 confirms that the loopback of the vehicle ID of the own vehicle has been successful, and maintains the communication of the own device as received at this time.
Conversely, the in-vehicle device 2 determines that the loopback of the vehicle ID of the host vehicle is not successful while the determination result is negative, switches the communication of the host device from reception to transmission, and sets the vehicle ID. A certain uplink frame UL1 is retransmitted.

  In this case, for example, the in-vehicle device 2 transmits the uplink frame UL1 with the vehicle ID again after a predetermined time (for example, 30 ms) has elapsed since the uplink frame UL1 with the vehicle ID has been transmitted. The in-vehicle device 2 repeats the retransmission operation of the uplink frame UL1 until the vehicle ID loopback is successful.

[Effect of optical beacon of the first embodiment]
According to the optical beacon 4 of the first embodiment, the beacon controller 7 does not include “simple graphic information” in the first downlink frame DL1 before receiving the uplink frame UL1 from the vehicle-mounted device 2, and from the vehicle-mounted device 2 Since communication control including “simple graphic information” in the second downstream frame DL2 after receiving the upstream frame UL1 is performed, only when the upstream frame UL1 is received from the in-vehicle device 2, the second downstream frame DL2 is simplified. Graphic information is transmitted in the downlink.

  In other words, only when the vehicle 20 (for example, the communication vehicle 20A shown in FIG. 7) that flows into the communication area A from the normal direction performs road-to-vehicle communication with the optical beacon 4 in the communication area A, the optical beacon 4 is simplified graphic information. The second downlink frame DL2 including the downlink is transmitted in the downlink, but the simple graphic information is not provided to the outside by the first downlink frame DL1 that is constantly downlink transmitted in other periods.

For this reason, compared to the case of communication control (communication control performed by the optical beacon 4 according to the current standard table) in which simple graphic information is included in both the first and second downlink frames DL1 and DL2, the simple graphic information is transmitted in the downlink. Can be greatly reduced.
Therefore, the possibility that the oncoming vehicle 20B receives the simple graphic information provided by the optical beacon 4 is reduced, and erroneous navigation can be prevented from being performed in the oncoming vehicle 20B.

[Variation 1 of the first embodiment]
In the first embodiment described above, focusing on “simple graphic information” as information that adversely affects the oncoming vehicle 20B, the provision condition is “none” in the current standard table of FIG. 6 (= uplink information need not be provided) ) For simple graphic information defined as), the provision condition is changed to “condition 2” (= when uplink information is provided), so that the simple graphic information is provided by the first downlink frame DL1. (Refer to the change table T0 in FIG. 9).

However, the 12 types of information included in the “basic information” in the current standard table (FIG. 6) indicate that the vehicle 20 traveling in the normal direction (the communication vehicle 20A traveling in the X direction in FIG. 7) communicates with the optical beacon 4. This information is defined assuming that
For this reason, although not as in the case of the simple graphic information, if the oncoming vehicle 20B acquires the 12 types of information included in the basic information, there may be a possibility of causing some trouble in the navigation device 25 of the oncoming vehicle 20B.

Therefore, the table of FIG. 10 (hereinafter referred to as “change table T1”) may be adopted as the provision of provision information that the optical beacon 4 should comply with. The hatched portion in FIG. 10 is the information type and provision condition portion obtained by changing the current standard table (FIG. 6).
As apparent from the comparison between FIG. 6 and FIG. 10, in the change table T1 of FIG. 10, not only “simple graphic information 1” and “simple graphic information 2” but also 12 types classified as “basic information”. The contents of all the “providing conditions” of the information of “1” are changed from “none” to “condition 2” (= when the in-vehicle device 2 provides uplink information).

  In this case, all twelve types of information classified as “basic information” are excluded from the provision targets by the first downlink frame DL1, and the condition is that the reception of the uplink frame (the data content of the uplink information is not required) is received. Downlink transmission is performed by two downlink frames DL2.

On the other hand, the lane notification information is used by the in-vehicle device 2 to determine the establishment of communication with the optical beacon 4 depending on whether or not the identification value is stored in the storage area of “vehicle ID”.
Therefore, if the lane notification information in which the identification value is not stored in the storage area of the vehicle ID is not included in the first downlink frame DL1, the in-vehicle device 2 cannot determine communication establishment with the optical beacon 4. For this reason, the lane notification information needs to be downlink transmitted by the first downlink frame DL1.

Therefore, in the change table T1 of FIG. 10, the “providing condition” of the lane notification information is set to “none” as it is, and the lane notification information without the vehicle ID is left as a provision target by the first downlink frame DL1. .
In the change table T1 in FIG. 10, the “providing condition” of the traffic jam link information remains the same as “condition 1” (= when the in-vehicle device 2 does not provide the uplink information), and the traffic jam link information. Is also left as a provision target by the first downlink frame DL1.

The reason is that, conventionally, the traffic jam link information is information that is positively defined as what should be provided to the in-vehicle device 2 even if the uplink information is not provided (see “Condition 1” in FIG. 6). This is because, unlike the case, the request to be provided by the first downlink frame DL is high.
Further, even if information indicating the position and degree of traffic congestion in link units is provided to the oncoming vehicle 20B, it is unlikely that there will be any particular inconvenience in the oncoming vehicle 20B, and it contributes to improving the route search accuracy of the oncoming vehicle 20B. This is because it is considered.

[Modification 2 of the first embodiment]
In the first modification of the first embodiment described above, the “providing conditions” of the 12 types of information included in the “basic information” are all changed to “condition 2”, and these pieces of information are provided by the first downlink frame DL1. Excluded from the target.

However, among the basic information, “current position information” is position information of the installation point of the beacon head 8 of the optical beacon 4, and even if such current position information is provided to the oncoming vehicle 20 </ b> B, there is a particular inconvenience. However, it can be said that it contributes to the improvement of the measurement accuracy of the current position of the oncoming vehicle 20B.
In addition, there is an in-vehicle device 2 that cannot determine communication establishment with the optical beacon 4 unless the “current position information” is acquired by the first downlink frame DL1.

Therefore, the table of FIG. 11 (hereinafter referred to as “change table T2”) may be adopted as the provision of provision information that the optical beacon 4 should comply with. In addition, the hatched part in FIG. 11 is the information type and provision condition part in which the current standard table (FIG. 6) is changed.
As is clear from the comparison between FIG. 6 and FIG. 11, in the change table T2 of FIG. 11, the contents of “providing conditions” of “current position information” among the 12 types of information classified as “basic information”. The “Provision condition” of the other 11 types of information changes from “None” to “Condition 2” (= when the in-vehicle device 2 provides uplink information). has been changed.

In this case, all eleven types of information other than the current position information are excluded from the provision targets of the first downlink frame DL1, and the second downlink information is received on condition that the uplink frame (the data content of the uplink information is not requested) is received. It is transmitted in downlink by frame DL2.
However, the current position information is not excluded from the target to be provided by the first downlink frame DL1, and is transmitted in the downlink by the first and second downlink frames DL1 and DL2 as it is currently.

In the change table T2 in FIG. 11 as well, the “providing condition” of the lane notification information is set to “none” as it is, and the lane notification information without the vehicle ID is left as a provision target by the first downlink frame DL1. Yes.
Also, in the change table T2 of FIG. 11, the “providing condition” of the traffic jam link information remains the same as “condition 1” (= when the in-vehicle device 2 does not provide the uplink information), and the traffic jam link information Information is also left as a provision target by the first downlink frame DL1.

[Second Embodiment: Problem Solving by Data Locking Process]
In the first embodiment described above, the oncoming vehicle 20B is simplified by performing communication control in which the optical beacon 4 does not include at least the simple graphic information in the first downlink frame DL1 among the information that may adversely affect the oncoming vehicle 20B. The possibility of acquiring graphic information is reduced.
However, in such communication control, it is necessary to change the provision conditions of the current standard table (FIG. 6) as shown in the change tables T0 to T2 of FIGS.

  Therefore, in the second embodiment, on the premise that communication control according to the current standard table (FIG. 6) is performed, the beacon controller 7 of the optical beacon 4 stores the simple graphic information in the actual data part. For the downlink frame DL1, the in-vehicle device 2 performs a data lock process (hereinafter simply referred to as “lock process”) that makes it impossible to extract information from the actual data part of the first downlink frame DL1, and then performs downlink transmission. To do.

If the above-described locking process is performed, the in-vehicle device 2 cannot receive the simple graphic information because it cannot be extracted even if it can receive the downlink frame DL1 storing the simple graphic information as some signal. During the transmission period of the frame DL1, the in-vehicle device 2 cannot use the simple graphic information.
That is, according to the optical beacon 4 of the second embodiment, the beacon controller 7 performs the above-described locking process on the first downlink frame DL1 that stores the simple graphic information. The simple graphic information included in the frame DL1 cannot be used, and only the simple graphic information included in the second downlink frame DL2 can be used.

In other words, the simple graphic information can be extracted only while the vehicle 20 (for example, the communication vehicle 20A shown in FIG. 7) that flows into the communication area A from the normal direction communicates with the optical beacon 4 in the communication area A. The downstream frame DL2 is transmitted.
However, since the first downlink frame DL1 storing the simple graphic information among the first downlink frames DL1 constantly transmitted in downlink during other periods is subjected to the lock process, The machine 2 cannot use the simple graphic information.

For this reason, compared with the case of the conventional communication control which does not perform a lock process in any of 1st and 2nd downlink frame DL1, DL2, the period when the vehicle equipment 2 can acquire simple figure information from the optical beacon 4 is large. Reduced to
Therefore, the possibility that the oncoming vehicle 20B acquires the simple graphic information provided by the optical beacon 4 is reduced, and erroneous navigation can be prevented in the oncoming vehicle 20B.

As a specific example of the lock process performed by the beacon controller 7 of the optical beacon 4 on the first downlink frame DL1, there is a process exemplified below, for example.
1) For the downlink frame DL1 that stores information (hereinafter referred to as “use avoidance information”) that is not used by the oncoming vehicle 20B, such as simple graphic information, the original CRC value in the “CRC portion” (see FIG. 5) Store a different value (eg, “0x0000”). In this case, the in-vehicle device 2 discards the received downlink frame DL1.
In order to release the lock process, a correct value may be stored in the CRC unit.

2) For the downlink frame DL1 storing the use avoidance information, the value of the “standard flag” defined in the “header part” (see FIG. 5) is set to “1” (= non-UTMS standard). In this case, the in-vehicle device 2 according to the UTMS standard discards the received downlink frame DL1.
In order to release the lock process, the value of the “standard flag” may be returned to “0” (= within the UTMS standard).

3) For the downlink frame DL1 storing the use avoidance information, the value of the “information flag” defined in the “header part” (see FIG. 5) is set to “1” (= test data). In this case, the in-vehicle device 2 determines that the downlink frame DL1 is a frame transmitted by a road administrator or the like for testing, and does not use the use avoidance information.
In order to release the lock process, the value of the “information flag” may be returned to “0” (= operation data).

4) For the downlink frame DL1 that stores the use avoidance information, the value of “information type” defined in the “header part” (see FIG. 5) is set to a value outside the specified range (other than 1 to 63). In this case, the in-vehicle device 2 determines that the type of provision information included in the downlink frame DL1 is outside the specified range, and does not use the use avoidance information.
In order to release the lock process, the value of “information type” may be returned to a correct value within the specified range.

5) For the downlink frame DL1 storing the use avoidance information, the value of “frame number within the same information type” in the “header part” (see FIG. 5) is set to a value outside the specified range (other than 1 to 80). In this case, the in-vehicle device 2 determines that the frame number of the downlink frame DL1 storing the use avoidance information is invalid, and does not use the use avoidance information.
In order to release this lock processing, the value of “frame number within the same information type” may be returned to a correct value within the specified range.

6) For the downlink frame DL1 that stores use avoidance information, the value of “frame data effective data length” in the “header portion” (see FIG. 5) is set to a value different from the original data length. In this case, the in-vehicle device 2 determines that the data length of the information included in the downlink frame DL1 is invalid and does not use the use avoidance information.
In order to release this lock processing, the value of “frame data effective data length” may be returned to the original correct data length value.

7) In all of the lock processes 1) to 6), a method of storing a data value that does not make sense even if the vehicle-mounted device 2 receives the data in the header portion of the downlink frame DL1 or the like is adopted. The data locking process for the DL is not limited to this.
For example, the data lock process may be a process of applying special encryption that cannot be decrypted by the in-vehicle device 2 to a predetermined part of the downlink frame DL1, or a process of performing encoding that the in-vehicle device 2 cannot synchronize to the preamble part. Good.

[Modification 1 of Second Embodiment]
In the second embodiment described above, attention is paid to “simple graphic information” as information that adversely affects the oncoming vehicle 20B, and only the first downlink frame DL1 storing the simple graphic information is subjected to data locking processing. Yes.

However, as described in the first modification of the first embodiment, although not as much as in the case of the simple graphic information, when the oncoming vehicle 20B acquires 12 types of information included in the basic information, the navigation device 25 of the oncoming vehicle 20B receives the information. There is also a possibility of causing some kind of malfunction.
Therefore, as in the case of the first modification of the first embodiment, in order to make it difficult for the oncoming vehicle 20B to acquire 12 types of information (see FIG. 6) included in the “basic information”, the information stored therein is stored in the first information storage device. All the downlink frames DL1 may be subjected to a lock process.

[Modification 2 of the second embodiment]
In the first modification of the second embodiment described above, the lock processing is performed on the first downlink frame DL1 storing the information for all 12 types of information (see FIG. 6) included in the “basic information”. ing.
However, as described in the second modification of the first embodiment, there is no particular inconvenience even if the “current position information” is provided to the oncoming vehicle 20B. If the current position information is not acquired, communication establishment with the optical beacon 4 is determined. Some in-vehicle devices 2 cannot be used.

  Therefore, as in the second modification of the first embodiment, among the 12 types of information classified as “basic information”, the downlink frame DL1 storing “current position information” is subject to lock processing. The downlink frame DL1 storing other 11 types of information may be subjected to a lock process.

[Others]
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the right of the present invention is shown not by the contents of the above-described embodiment but by the scope of claims, and is intended to include meanings equivalent to the scope of claims and all modifications within the scope.

  For example, in the above-described first embodiment (including modifications 1 and 2), the “congestion link information” is provided by the first downlink frame DL1 (“Condition 1” in FIGS. 9 to 11). The traffic jam link information is excluded from the target to be provided by the first downlink frame DL1, and the traffic jam link information is provided to the in-vehicle device 2 during the transmission period of the first downlink frame DL1 before receiving the uplink. You may decide not to.

  In the second embodiment described above (including Modifications 1 and 2), the first downlink frame DL1 storing “congestion link information” is not a target of data lock processing. The first downlink frame DL1 storing the data is subjected to data lock processing, and the traffic jam link information is not used by the in-vehicle device 2 during the transmission period of the first downlink frame DL1 before uplink reception. Good.

DESCRIPTION OF SYMBOLS 1 Traffic control system 2 Car equipment 3 Central equipment 4 Optical beacon 5 Communication line 6 Communication part 7 Beacon controller (communication control part)
8 Beacon head (emitter / receiver)
11 Transmitter / receiver unit (optical transmitter / receiver)
12 sensor unit 13 light emitting unit for communication 14 light receiving unit for communication 15 light emitting unit for sensing 16 light receiving unit for sensing 17 support 18 beam member 20 vehicle 20A communication vehicle 20B oncoming vehicle 21 vehicle mounted controller 22 vehicle mounted head 23 light transmission Unit 24 Optical receiver 25 Navigation device 31 Housing UL1 Up frame DL1 First down frame DL2 Second down frame

Claims (6)

An optical beacon that performs wireless communication with an in-vehicle device of a running vehicle using an optical signal,
An optical transmission / reception unit for receiving an upstream frame composed of the optical signal and transmitting a downstream frame composed of the optical signal;
An optical beacon comprising: a communication control unit that does not include the simple graphic information defined below in the first downlink frame defined below but includes the simple graphic information in the second downlink frame defined below.
First downlink frame: a downlink frame in which transmission is continued at a predetermined transmission period until an uplink frame is received from the in-vehicle device. Second downlink frame: a downlink transmitted for a predetermined time when an uplink frame is received from the in-vehicle device. Frame Simple graphic information: Information that includes simple graphic patterns of road traffic information The communication control unit includes only the lane notification information defined below and the traffic jam link information defined below, in which the identification value of the vehicle ID is not stored in the storage area of the vehicle ID, in the first downlink frame. The optical beacon according to claim 1.
Lane notification information: Information including the storage area of vehicle ID and lane number Traffic jam link information: Information representing the location and degree of traffic jam in link units The communication control unit only stores lane notification information defined below, traffic link information defined below, and current position information defined below, in which the identification value of the vehicle ID is not stored in the storage area of the vehicle ID. The optical beacon according to claim 1, which is included in the first downstream frame.
Lane information: Information including the storage area of the vehicle ID and lane number Traffic congestion link information: Information indicating the location and degree of traffic congestion in units of links Current location information: Location information indicating the location of the beacon head of the optical beacon An optical beacon that performs wireless communication with an in-vehicle device of a running vehicle using an optical signal,
An optical transmission / reception unit for receiving an upstream frame composed of the optical signal and transmitting a downstream frame composed of the optical signal;
An optical beacon comprising: a communication control unit that performs a data lock process on the first downlink frame that stores the simple graphic information defined below among the first and second downlink frames defined below.
First downlink frame: a downlink frame in which transmission is continued at a predetermined transmission period until an uplink frame is received from the in-vehicle device. Second downlink frame: a downlink transmitted for a predetermined time when an uplink frame is received from the in-vehicle device. Frame Simple graphic information: Information that includes simple graphic patterns of road traffic information   The said communication control part performs the said lock process to the said 1st downstream frame which stores the information of the said kind about all the information classified into the basic information in which the said simple figure information is contained in a classification | category. The optical beacon described in 1. The communication control unit is configured to store information other than the current position information defined below among a plurality of types of information classified as basic information including the simple graphic information in the first downlink frame. The optical beacon according to claim 4 which performs said lock processing.
Current position information: Position information indicating the installation location of the beacon head of the optical beacon

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