JP2010258581A - Roadside communication device, and road-to-vehicle communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a roadside communication device and road-to-vehicle communication system, capable of improving reliability of road-to-vehicle communication regardless of presence of an obstructive factor. <P>SOLUTION: An optical beacon 20 includes: a floodlight unit 21 for transmitting a transmission signal to an on-vehicle communication device 10; an obstruction information acquisition unit 23a for acquiring obstruction information related to an obstructive factor of transmission of the transmission signal; and a transmission control unit 23b for controlling a transmission form of the transmission signal by the floodlight unit 21 based on the obstruction information acquired by the obstruction information acquisition unit 23a. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a roadside communication device and a road-vehicle communication system that can be used in, for example, an intelligent road traffic system.

In recent years, for the purpose of promoting traffic safety improvement and preventing traffic accidents, intelligent road traffic has been improved by receiving information from infrastructure devices installed on the road and using this information to improve vehicle safety. The system is being considered.
Such an intelligent road traffic system is composed of a plurality of roadside communication devices on the infrastructure side and an in-vehicle communication device (mobile communication device) mounted on each vehicle, and between the roadside communication device and the in-vehicle communication device. It includes a road-to-vehicle communication system for two-way communication. The roadside communicator communicates with the in-vehicle communicator to transmit information necessary for the safe driving support of the vehicle, such as information on the light color of the signal located in front of the traveling direction of the vehicle, traffic jam information, etc. To the machine. (For example, refer to Patent Documents 1 and 2).

Japanese Patent No. 2806801 JP 2005-268925 A

In the road-vehicle communication system, road-vehicle communication is performed by wireless communication or optical communication using near infrared rays as a communication medium. For this reason, when there are raindrops or vehicle wipers that operate in conjunction with rain, etc., in the space between the roadside communication device and the in-vehicle communication device, which becomes a wireless or near infrared propagation path during rain, etc. Therefore, transmission / reception of transmission signals between the two communication devices is hindered. As described above, when there is an obstacle to road-to-vehicle communication such as rainfall, the reliability of road-to-vehicle communication may be reduced.
For this reason, in a road-to-vehicle communication system, a policy that can provide safe driving support more reliably by increasing the reliability of road-to-vehicle communication regardless of the presence or absence of an obstruction factor has been desired.

  This invention is made in view of such a situation, and it aims at providing the roadside communication apparatus and road-vehicle communication system which can improve the reliability of road-vehicle communication irrespective of the presence or absence of an obstruction factor. To do.

  (1) The present invention is a roadside communication device that performs road-to-vehicle communication with a mobile communication device mounted on a vehicle, the transmission means for transmitting a transmission signal to the mobile communication device, and the transmission signal Acquisition means for acquiring inhibition information relating to a propagation inhibition factor, and control means for controlling a transmission mode of the transmission signal by the transmission means based on the inhibition information acquired by the acquisition means. It is characterized by.

  According to the roadside communication device having the above configuration, the control unit controls the transmission mode of the transmission signal based on the inhibition information regarding the inhibition factor that inhibits the transmission of the transmission signal by the transmission unit. A transmission signal can be transmitted by a transmission mode corresponding to the type. As a result, the reliability of road-to-vehicle communication can be enhanced regardless of the presence or absence of various obstruction factors.

(2) Specifically, it is preferable that the inhibition information includes information indicating the current weather.
In the case of bad weather such as rain or yellow sand floating, there are raindrops, yellow sand, etc. between the roadside communication device and the mobile communication device, that is, the propagation path of each other's communication signal. It becomes an obstruction factor that inhibits propagation. In other words, depending on whether the weather is good or bad, the obstruction status in transmitting the transmission signal varies. For this reason, the acquisition means acquires information indicating the current weather as inhibition information, so that the control means can grasp the inhibition status in transmitting the transmission signal, and the transmission means according to the inhibition status The transmission mode of the transmission signal by can be controlled more appropriately.

(3) Furthermore, the transmission means transmits a transmission signal transmitted by the transmission means to the mobile communication device through a wiped member of the vehicle wiped by a wiper device provided in the vehicle. The inhibition information may include a moving speed of the mobile communication device.
In this case, if the weather is raining, in addition to the presence of raindrops in the propagation path of the communication signal, a wiper device for a vehicle that performs a wiping operation on the member to be wiped along with the rain is present in the propagation path. For this reason, the wiper device becomes an obstructive factor that inhibits transmission signal transmission. This wiper device is set to stop or slow wiping operation when the moving speed of the mobile communication device (vehicle) is relatively slow, and to wipe at high speed if the moving speed is relatively fast. The That is, the obstruction status by the wiper device varies depending on the weather and the moving speed of the mobile communication device.
For this reason, in addition to the current weather, the acquisition unit acquires the moving speed of the mobile communication device as inhibition information, so that the control unit can more reliably grasp the inhibition state in transmitting the transmission signal. The transmission mode of the transmission signal by the transmission means can be controlled more appropriately according to the inhibition status.

(4) The transmission signal is a signal in which a plurality of different types of transmission information are repeatedly arranged and transmitted, and the control means transmits the plurality of types of transmission information in the transmission signal based on the inhibition information. The transmission mode of the transmission signal may be controlled by setting the order of information arrangement.
Since the wiper device performs the wiping operation at a constant timing, if the transmission signal is transmitted with the transmission information arrangement that matches this timing, the transmission of the transmission signal is inhibited by the wiping operation of the wiper device. The transmission information to be transmitted is always obstructed and the possibility of transmission failure increases. On the other hand, according to the above configuration, when it is estimated that the wiper device is performing a wiping operation due to rain, the order of transmitting a plurality of types of transmission information is set so as not to coincide with the timing of the wiper device. can do. As a result, the probability that the transmission of the same transmission information is always obstructed can be reduced, and the reliability of road-to-vehicle communication can be further increased.

(5) In the roadside communication device, the acquisition unit estimates and acquires the stay time of the mobile communication device entering the communication region on the road where the transmission unit can transmit as the inhibition information. You may do.
In this case, if the staying time during which the mobile communication device stays in the communication area is short, the time during which the mobile communication device can communicate with the mobile communication device becomes short. That is, when this staying time is short, there is a possibility that necessary transmission information cannot be transmitted to the mobile communication device.
For this reason, the acquisition unit acquires the stay time in the communication area of the mobile communication device as the inhibition information, so that the control unit can more reliably grasp the inhibition state, and according to the inhibition state, by the transmission unit The transmission mode of the transmission signal can be controlled more appropriately.

(6) In the roadside communication device, the transmission signal is a signal in which predetermined transmission information is repeatedly arranged a predetermined number of times, and the control unit arranges the transmission information based on the inhibition information. It is preferable that the transmission mode of the transmission signal is controlled by adjusting the number of repetitions.
In this case, when it is grasped that there is an obstruction factor based on the obstruction information, it is possible to increase the chance that the mobile communication device receives the transmission information by adjusting to increase the number of repetitions. it can. As a result, it is possible to further improve the reliability of road-to-vehicle communication when there is an obstruction factor in transmitting the transmission signal.

(7) Further, the transmission signal is a signal in which a plurality of different types of transmission information is repeatedly arranged and transmitted, and the control means sets the priority set for each of the plurality of types of transmission information. Accordingly, the transmission mode of the transmission signal may be controlled by adjusting the transmission frequency of each of the plurality of types of transmission information.
In this case, it is possible to increase the opportunity for the mobile communication device to receive transmission information with a higher priority by adjusting the transmission frequency of transmission information with a higher priority among a plurality of types of transmission information. As a result, even when there is an obstruction factor in transmitting a transmission signal, transmission information with high priority can be received by the mobile communication device.

(8) The transmission signal is a signal in which a plurality of different types of transmission information are repeatedly arranged and transmitted, and the control unit is configured to transmit the plurality of types according to the data size of each of the plurality of types of transmission information. It is preferable that the transmission mode of the transmission signal is controlled by adjusting the transmission frequency of each type of transmission information.
When there is an obstruction factor for the transmission signal, when transmitting transmission information with a large data size, there is a high possibility that the transmission signal will be blocked during transmission of the transmission information and the transmission will fail. On the other hand, with the above configuration, the mobile communication device has an opportunity to receive transmission information with a large data size by adjusting the transmission frequency of transmission information with a larger data size among a plurality of types of transmission information. Can be increased. As a result, when there is an obstruction factor for the transmission signal, it is possible to effectively suppress the transmission of transmission information having a large data size from being failed, and the reliability of road-to-vehicle communication can be further improved.

(9) The roadside communication device further includes a storage unit that stores a database for controlling a transmission mode of the transmission signal based on the inhibition information, and the control unit uses the transmission unit based on the database. The transmission mode of the transmission signal may be controlled.
In this case, if the control means refers to the database, it can grasp the transmission mode according to the inhibition information, and the control of the transmission means becomes easy.

  (10) Further, the present invention is a road-vehicle communication system including a mobile communication device mounted on a vehicle and a road-side communication device that performs road-vehicle communication with the mobile communication device. The machine is based on the transmission information for transmitting the transmission signal to the mobile communication device, the acquisition means for acquiring the inhibition information about the transmission signal propagation inhibition factor, and the inhibition information acquired by the acquisition means, Control means for controlling a transmission mode of the transmission signal by the transmission means.

  According to the road-to-vehicle communication system having the above-described configuration, as described above, the reliability of road-to-vehicle communication can be improved regardless of the presence, form, and type of various obstruction factors.

  As described above, according to the roadside communication device and the road-to-vehicle communication system of the present invention, the reliability of road-to-vehicle communication can be improved regardless of the presence, mode, and type of various obstruction factors.

It is a block diagram which shows the structure of the road-vehicle communication system of this invention. It is a side view which shows the vehicle-mounted communication apparatus mounted in the optical beacon and the vehicle. It is a block diagram which shows the structure of an optical beacon and a vehicle-mounted communication apparatus. It is a figure which shows an example of the transmission frame transmitted from a light projection part. It is a figure which shows an example of the database for control which the memory | storage part has memorize | stored.

[Overall system configuration]
FIG. 1 is a block diagram showing a configuration of a road-vehicle communication system according to the present invention.
As shown in FIG. 1, the road-to-vehicle communication system includes an infrastructure-side traffic control system 1 and an in-vehicle communication device (mobile communication device) 10 mounted on a plurality of vehicles traveling on a road. The traffic control system 1 includes a central device 2 provided in a control room and a large number of optical beacons (optical vehicle detectors) 20 installed in various places on the road. The optical beacon 20 transmits near infrared rays. Bidirectional communication is performed with the in-vehicle communication device 10 by optical communication as a communication medium. The central device 2 is provided in the traffic control room.

FIG. 2 is a side view showing the optical beacon 20 and the in-vehicle communication device 10 mounted on the vehicle.
The optical beacon 20 is installed on a column or the like standing on the side of the road, and is arranged immediately above the lane of the road R. The optical beacon 20 includes a light projecting unit 21 made of an LED or the like, and a light receiving unit 22 made of a photo sensor or the like.
The light projecting unit 21 constitutes a transmission unit that transmits near-infrared transmission signals to the in-vehicle communication device 10 that receives near-infrared rays by emitting near-infrared rays. The light projecting unit 21 emits near-infrared light toward the upstream side from directly below itself, and the communication area A for performing road-to-vehicle communication with the in-vehicle communication device 10 is located upstream of the optical beacon 20 ( The right side of FIG. 2 is set. The light projecting unit 21 can transmit a transmission signal to the in-vehicle communication device 10 located in the communication area A.
The light receiving unit 22 receives various information from the in-vehicle communication device 10 by receiving a transmission signal composed of near infrared rays from the in-vehicle communication device 10.

The in-vehicle communication device 10 has a light projecting / receiving unit for performing optical communication with the optical beacon 20, and can exchange various information with the optical beacon 20 using near infrared rays as a communication medium. .
When the vehicle C equipped with the in-vehicle communication device 10 enters the communication area A, the in-vehicle communication device 10 recognizes that it has entered the communication area A and starts bidirectional communication with the optical beacon 20. Note that the optical beacon 20 always transmits information for causing the in-vehicle communication device 10 to recognize that it is the communication area A. By receiving this information, the in-vehicle communication apparatus 10 has entered the communication area A. recognize.

The in-vehicle communication device 10 transmits information regarding its own ID, the current moving speed of the vehicle C, and the like to the optical beacon 20.
On the other hand, the optical beacon 20 transmits traffic information transmitted from the central device 2 to the in-vehicle communication device 10 located in the communication area A, the light color of the traffic light 30 located on the downstream side of the optical beacon 20, and the traffic light Support information for safe driving support for the driver of the vehicle C, such as a distance to the stop line 31 provided in front of 30, is transmitted as transmission information.
The in-vehicle communication device 10 that has received the support information performs safe driving support for the driver of the vehicle C based on the support information (transmission information).

  As described above, the road-to-vehicle communication system can perform safe driving support for vehicles on the road R by performing bidirectional communication between the optical beacon 20 and the in-vehicle communication device 10.

[Configuration of in-vehicle communication device]
FIG. 3 is a block diagram showing configurations of the optical beacon 20 and the in-vehicle communication device 10.
The in-vehicle communication device 10 mounted on the vehicle C includes a light projecting / receiving unit 11 for performing optical communication with the optical beacon 20 and a control unit 12. As described above, the light projecting / receiving unit 11 exchanges information with the optical beacon 20 using near infrared rays as a communication medium. The light projecting / receiving unit 11 is fixed on the front dashboard 40 in the vehicle C, and performs optical communication by receiving a transmission signal from the optical beacon 20 that reaches through the windshield 41.

  The control unit 12 includes a microcomputer having a CPU, a memory (RAM), a storage device, and the like, and has a function of performing communication control for performing road-to-vehicle communication by the light projecting / receiving unit 11. Further, the control unit 12 acquires information necessary for performing safe driving support such as the current moving speed detected by the vehicle speed sensor 43 from the vehicle control unit 42 that controls the vehicle C. The control unit 12 generates specific support information for safe driving support based on the acquired information and information transmitted from the optical beacon 20, and is illustrated to make the driver of the vehicle C recognize the support information. Output to notifying means such as a display. In addition, the information regarding the present moving speed detected by the vehicle speed sensor 43 is transmitted to the optical beacon 20 through the light projector / receiver 11 in addition to being used by the control unit 12.

  The vehicle control unit 42 of the vehicle C is connected to the wiper device 44 for wiping the windshield 41 of the vehicle C in addition to the vehicle speed sensor 43 described above. The wiper device 44 includes a wiper blade 44a for wiping raindrops and the like on the outer surface of the windshield 41, and a wiper control unit 44b for controlling the wiping operation of the wiper blade 44a. The wiper control unit 44b controls the operation of the wiper blade 44a by the operation of the driver of the vehicle C. The wiping operation of the wiper blade 44a is selected by the driver according to the weather and the speed of the vehicle C from among stop, low speed operation, and high speed operation.

[Configuration of optical beacon]
The optical beacon 20 includes, in addition to the light projecting unit 21 and the light receiving unit 22 described above, a communication control unit 23 that controls them, a communication unit 24 for performing bidirectional communication with the central device 2, and the optical beacon. A rain sensor 25 for detecting whether or not the place where 20 is installed is raining, and a storage unit 26 for storing information necessary for performing various controls.

The communication control unit 23 includes a microcomputer having a CPU, a memory (RAM), a storage device, and the like. The communication control unit 23 performs bidirectional communication with the central device 2 by the communication unit 24 and the in-vehicle communication device 10 by the light projecting and receiving units 21 and 22. It has a function as a control part for performing road-to-vehicle communication.
The communication control unit 23 controls an inhibition information acquisition unit 23 a that acquires inhibition information indicating the presence or absence of an inhibition factor that inhibits transmission signal transmission by the light projecting and receiving units 21 and 22, and a transmission mode of the transmission signal by the light projecting unit 21. Functionally having a transmission control unit 23b.

  In the optical communication performed between the optical beacon 20 and the in-vehicle communication device 10, the space between the optical beacon 20 and the in-vehicle communication device 10 is a near-infrared propagation path as a communication medium. If yellow sand or the like is present in the space between the optical beacon 20 and the in-vehicle communication device 10, the near infrared light projected from one side is irregularly reflected and does not reach the other accurately, and the propagation of signals transmitted and received between the two It becomes an inhibiting factor that inhibits. Further, when it rains, the driver of the vehicle C operates the wiper device 44 in order to wipe the raindrops on the surface of the windshield 41, and therefore the vehicle-mounted communication device 10 and the optical beacon that perform optical communication by transmission / reception signals passing through the windshield 41. The wiper blade 44a of the wiper device 44 is also present between the wiper device 44 and the wiper device 44. As described above, when the current weather is rainy or when the yellow sand is floating, there are obstacles to the transmission / reception signal, and conversely, when the weather is sunny or cloudy, The wiper blade 44a does not exist and the transmission / reception signal propagation between them is not hindered by these.

  Further, when the driver of the vehicle C operates the wiper device 44 in rainy weather, the operation speed of the wiping operation of the wiper blade 44a is adjusted by the moving speed of the vehicle C. When the moving speed of the vehicle C is relatively slow, it is set to stop or set to a low speed operation, the frequency of blocking near infrared rays for communication is low, and set to operate at a high speed if the moving speed is relatively high. The frequency with which transmission / reception signals made of near infrared rays are blocked increases. That is, in the case of rainy weather, the state of inhibition of the transmission signal by the wiper device 44 varies depending on the moving speed of the vehicle C (the in-vehicle communication device 10).

Furthermore, since the light projecting unit 21 sets the communication area A for performing road-to-vehicle communication with the in-vehicle communication device 10 on the upstream side of the optical beacon 20 (see FIG. 2), the optical beacon 20 Communication is possible from when the in-vehicle communication device 10 enters the communication area A until it exits.
Therefore, if the staying time during which the in-vehicle communication device 10 stays in the communication area A is short, the time during which communication with the in-vehicle communication device 10 can be performed is shortened. That is, when this staying time is short, there is a possibility that necessary information cannot be transmitted to the in-vehicle communication device 10, and it can be said that it becomes an obstructive factor that inhibits transmission / reception signal propagation.
Since the distance width a (FIG. 2) of the communication area A is set in advance, the stay time can be estimated from the moving speed of the vehicle C. That is, the staying time, which is a factor that inhibits transmission / reception signals, depends on the moving speed of the vehicle C.

  As described above, the current weather and the moving speed of the vehicle C affect the inhibition factors that inhibit the transmission of the transmission signal, and as inhibition information indicating the presence or absence of the inhibition factors that inhibit the transmission of the transmission signal. Can be used.

Therefore, the inhibition information acquisition unit 23a acquires information indicating the current weather and the moving speed of the vehicle C as inhibition information.
Specifically, the inhibition information acquisition unit 23a determines whether the current weather is rainy or not based on the detection result of the rainfall sensor 41, and acquires information on the current weather. Moreover, the inhibition information acquisition part 23a can also acquire the information regarding the present weather, the information regarding whether yellow sand is floating, etc. from the central apparatus 2 via the communication part 24.
Further, the moving speed of the vehicle C can be acquired from transmission information from the in-vehicle communication device 10 received by the light receiving unit 22.
Moreover, the inhibition information acquisition part 23a calculates | requires the stay time that the vehicle-mounted communication apparatus 10 stays in the communication area A based on the moving speed of the vehicle C, and acquires it as inhibition information.

The transmission control unit 23b controls the transmission mode of the transmission signal by the light projecting unit 21 based on the inhibition information acquired by the inhibition information acquisition unit 23a.
FIG. 4 is a diagram illustrating an example of a transmission frame transmitted from the light projecting unit 21. In the illustrated example, the optical beacon 20 transmits three different types of transmission information A, B, and C to the in-vehicle communication device 10, the weather is fine, and each information A, B, and C There is no difference in the accompanying priorities.
As shown in the figure, the transmission signal transmitted from the light projecting unit 21 is transmitted with transmission information A, transmission information B, and transmission information C arranged, and transmission information A, transmission information B, transmission Transmission patterns set in the order of information C are repeatedly arranged.
The transmission control unit 23b of the optical beacon 20 transmits the transmission signal transmitted from the light projecting unit 21 by repeatedly arranging transmission patterns set in the order of transmission information A, transmission information B, and transmission information C. The projector 21 is controlled as described above.
In the present embodiment, the transmission mode of the transmission signal is a form of arrangement of transmission information in the transmission frame F shown in FIG. 4, and the transmission control unit 23b controls the arrangement of transmission information in the transmission frame F.

The storage unit 26 stores a control database used by the transmission control unit 23b to control the transmission mode of transmission signals.
As described later, the control database includes a plurality of different transmission patterns. Here, the transmission pattern will be described as an arrangement of each piece of transmission information when three types of transmission information A, B, and C different from each other are transmitted.
The transmission control unit 23b refers to the control database in the storage unit 26 and selects one of the transmission patterns when controlling the transmission mode of the transmission signal. The light projecting unit 21 repeats one transmission pattern selected by the transmission control unit 23b, arranges each transmission information in the transmission frame F, and transmits each transmission information to the in-vehicle communication device 10.

The transmission control unit 23b selects one transmission pattern from the control database based on the current weather and the moving speed of the vehicle C given from the inhibition information acquisition unit 23a, and arranges the transmission information in the transmission frame F. By determining, the transmission mode of the transmission signal is controlled.
Table 1 below shows each transmission pattern of the control database selected by the transmission control unit 23b according to the current weather and the moving speed of the vehicle C.

In Table 1, according to the current weather, the moving speed of the vehicle C, the priority set in each transmission information, etc., each transmission pattern (a-1 to d-2) included in the control database shown in FIG. -2, see FIG. 5).
As shown in Table 1, the transmission control unit 23b determines whether the weather condition is good (sunny, cloudy) or bad (rainfall, yellow sand) based on the current weather information. .
Further, the moving speed of the vehicle C is determined based on a predetermined threshold value, which is “fast” or “slow”.

Further, when a priority is set for each transmission information, the transmission control unit 23b adjusts the transmission frequency by adjusting the number of pieces of each transmission information arranged in the transmission pattern according to the priority. To do. Therefore, as shown in Table 1, the transmission control unit 23b determines whether there is a difference in priority among the pieces of transmission information. In addition, when there is a difference in priority among a plurality of pieces of transmission information, a large number of patterns can be considered, but in Table 1 above, transmission information A has the highest priority among three different pieces of transmission information A to C. Then, only the case where the transmission information B and C and the priorities sequentially become lower is illustrated.
Note that the transmission information having a high priority includes information on the light color of the traffic light 30 (FIG. 2) on the downstream side of the optical beacon 20. The transmission information having a medium priority includes a distance to the stop line 31 (FIG. 2) provided in front of the traffic light 30. Examples of transmission information with low priority include traffic information such as traffic jams.

  If there is a difference in the data size of each piece of transmission information, the transmission control unit 23b adjusts the transmission frequency by adjusting the number of pieces of transmission information arranged in the transmission pattern according to the data size. . Therefore, as shown in Table 1, the transmission control unit 23b determines whether there is a difference in data size between pieces of transmission information. In Table 1, the case where there is no difference in the data size illustrates the case where each transmission information is all 100 bytes, and the case where there is a difference in the data size, the transmission information A is 100 bytes, the transmission information A case where B is 200 bytes and transmission information C is 300 bytes is illustrated.

FIG. 5 is a diagram illustrating an example of a control database stored in the storage unit 26. As shown in the figure, the control database includes a plurality of different transmission patterns. In the plurality of transmission patterns, each piece of transmission information is arranged with a minimum unit of 100 bytes.
The plurality of transmission patterns correspond to the conditions such as the weather and the moving speed of the vehicle C shown in Table 1, and transmission of the transmission signal including each transmission information can be more suitably performed under the corresponding conditions. It is set to be possible.
Therefore, if the transmission control part 23b selects the transmission pattern according to the weather and the moving speed of the vehicle C based on Table 1, the light transmission part 21 can transmit the transmission signal more suitably.

  As described above, the optical beacon 20 of the present embodiment includes the storage unit 26 that stores the control database for controlling the transmission mode of the transmission signal based on the inhibition information, and thus the transmission control unit 23b. By referring to this control database, a suitable transmission mode corresponding to the inhibition information can be grasped, and the transmission means can be easily controlled.

Here, the control of the transmission mode of the transmission signal of the transmission control unit 23b will be described with reference to Table 1 and FIG.
As described above, when there is a difference in the priority of each piece of transmission information, the transmission control unit 23b adjusts the number of pieces of each piece of transmission information arranged in the transmission pattern according to the priority. Adjust. In FIG. 5, the pattern a-1 and the pattern b-1 all have the same conditions except for the presence or absence of the priority difference between the pieces of transmission information. Looking at these patterns a-1 and b-1, in the transmission pattern b-1 having no difference in priority, each piece of transmission information is arranged in order. On the other hand, in the transmission pattern a-1 having different priorities, the transmission information A having the highest priority is arranged in a larger number than the other transmission information, and the transmission frequency is increased. Yes.
In addition, when the transmission pattern a-1 and the transmission pattern c-1-1 are all the same except for the difference in weather, the transmission pattern c-1-1 in which the weather is “bad” has priority. The transmission information A having the highest degree is arranged at a ratio of 5/6.
In this way, the transmission control unit 23b is configured to adjust so as to increase the transmission frequency of transmission information with high priority, whereby the in-vehicle communication device 10 receives transmission information with higher priority. Opportunities can be increased. As a result, even when there is an obstruction factor in transmitting the transmission information, the in-vehicle communication device 10 can receive the transmission information with high priority.

  Moreover, when it is grasped that the weather is bad and there is an obstruction factor of information transmission like the transmission information A in the transmission pattern a-1 and the transmission pattern c-1-1, transmission control is performed. The unit 23b adjusts the number of repetitions to increase, thereby increasing the opportunity for the in-vehicle communication device 10 to receive transmission information. As a result, it is possible to further improve the reliability of road-to-vehicle communication when there is an obstruction factor in transmitting the transmission signal.

  As described above, when there is a difference in the data size of each piece of transmission information, the transmission control unit 23b adjusts the number of pieces of each piece of transmission information arranged in the transmission pattern according to the data size. Adjust. In FIG. 5, the pattern b-2 and the pattern d-2-2 are all the same except for the difference in weather between the transmission information, and the pattern when the data size is different. is there. Looking at both patterns b-2 and d-2-2, the arrangement of the transmission information C having the largest data size in the pattern d-2-2 compared to the transmission pattern b-2 in which the weather is “good”. The number is relatively large and the transmission frequency is increased.

  When there is an obstruction factor for the transmission signal, when transmitting transmission information with a large data size, there is a high possibility that the transmission is inhibited during transmission of the transmission information and the transmission fails. On the other hand, in the present embodiment, the transmission control unit 23b adjusts so as to increase the transmission frequency of transmission information having a larger data size among the pieces of transmission information as described above. Opportunities for receiving transmission information with a large data size can be increased. As a result, when there is an obstruction factor for the transmission signal, it is possible to effectively suppress the transmission of transmission information having a large data size from failing, and the reliability of road-to-vehicle communication can be further improved.

Also, the transmission control unit 23b is arranged so that each piece of transmission information does not appear at regular intervals with respect to the time axis when the weather is "bad". Specifically, as shown in the transmission pattern d-1-2 in FIG. 5, the transmission information A to C is randomly arranged so that each transmission information does not appear at regular intervals with respect to the time axis. Has been.
Here, since the wiper device 44 of the vehicle C performs the windshield 41 wiping operation at a fixed timing, if the transmission signal is transmitted with the transmission information arrangement that coincides with this timing, the wiping operation of the wiper device 44 is performed. Therefore, transmission information transmitted at a timing at which propagation of a transmission signal is hindered is always hindered and the possibility of transmission failure increases. On the other hand, in this embodiment, when it is estimated that the wiper device 44 is performing a wiping operation due to rain (when the weather is “bad”), the transmission information A to C is randomly arranged. Thus, since the transmission information does not appear at regular intervals with respect to the time axis, the order of transmitting the transmission information is set so as not to coincide with the timing of the wiper device. As a result, the probability that transmission of the same transmission information is always hindered by the operation of the wiper device 44 can be reduced, and the reliability of road-to-vehicle communication can be further increased.

Moreover, the transmission control part 23b sets arrangement | positioning of each transmission information according to the moving speed of the vehicle C. FIG. For example, in FIG. 5, when the transmission pattern c-1-1 and the transmission pattern c-1-2 that are different only in the moving speed of the vehicle C are compared, While the transmission information A having the highest priority is arranged at a rate of 5/6, in the pattern c-1-2 having a slow moving speed, the transmission information A is arranged at a rate of 4/6 and the others are assigned to the transmission signal B. Is set to
When the moving speed of the vehicle C is high, the staying time during which the vehicle C stays in the communication area A is short, or the operation speed of the wiping operation of the wiper device 44 is set to a relatively high speed. 21 prevents transmission of transmission information. On the other hand, if the moving speed of the vehicle C is high, the transmission control unit 23b is configured to increase the number of arrangements of the necessary transmission information as described above and increase the transmission frequency. As a result, when there is a hindrance to the transmission signal, it is possible to effectively suppress failure of transmission of necessary transmission information, and the reliability of road-to-vehicle communication can be further improved.

  According to the optical beacon 20 configured as described above, the transmission control unit 23b changes the transmission mode of the transmission signal based on the inhibition information indicating the presence / absence of an inhibition factor that inhibits the propagation of the transmission signal by the light projecting unit 21. Since it controls, a transmission signal can be transmitted by the suitable transmission aspect according to the presence or absence of the obstruction factor. As a result, the reliability of road-to-vehicle communication can be improved regardless of the presence or absence of an obstruction factor.

  Further, in the optical beacon 20, information indicating that the inhibition information acquisition unit 23 a indicates the current weather, the moving speed of the vehicle C, and the staying time during which the vehicle C (the in-vehicle communication device 10) stays in the communication area A are used as inhibition information. Since acquisition is performed, the transmission control unit 23b can grasp the inhibition state in transmitting the transmission signal, and more appropriately control the transmission mode of the transmission signal by the light projecting unit 21 according to the inhibition state. Can do.

  The present invention is not limited to the above embodiment. In the above-described embodiment, the case where the present invention is applied to a road-vehicle communication system that performs optical communication using an optical beacon as a roadside communication device has been exemplified. However, for example, the present invention is applied to a road-vehicle communication system using wireless communication. You can also.

  With respect to the present invention, the embodiments disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is not meant to be described above, but is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

10 In-vehicle communication device (mobile communication device)
20 Optical beacon (roadside communication device)
21 Projection unit 23a Inhibition information acquisition unit (acquisition means)
23b Transmission control unit (control means)
26 storage unit (storage means)
41 Windshield (wiping member)
44 Wiper device C Vehicle

Claims (10)

A roadside communication device that performs road-to-vehicle communication with a mobile communication device mounted on a vehicle,
Transmitting means for transmitting a transmission signal to the mobile communication device;
An acquisition means for acquiring inhibition information related to a transmission inhibition factor of the transmission signal;
And a control unit that controls a transmission mode of the transmission signal by the transmission unit based on the inhibition information acquired by the acquisition unit.   The roadside communication device according to claim 1, wherein the inhibition information includes information indicating current weather. The transmission means is provided such that a transmission signal transmitted by the transmission means is transmitted to the mobile communication device through a wiped member of the vehicle that is wiped by a wiper device provided in the vehicle. ,
The roadside communication device according to claim 1 or 2, wherein the inhibition information includes a moving speed of the mobile communication device. The transmission signal is transmitted by repeatedly arranging a plurality of different types of transmission information,
The roadside communication device according to claim 3, wherein the control means controls the transmission mode of the transmission signal by setting the order of arrangement of the plurality of types of transmission information in the transmission signal based on the inhibition information. .   5. The acquisition unit according to claim 1, wherein the acquisition unit estimates and acquires, as the inhibition information, a stay time in the communication area of the mobile communication device that enters a communication area on a road that can be transmitted by the transmission unit. The roadside communication device according to one item. The transmission signal is transmitted with predetermined transmission information repeatedly arranged a predetermined number of times,
The said control means controls the transmission mode of the said transmission signal by adjusting the repetition frequency at the time of arrange | positioning the said transmission information based on the said obstruction information. Roadside communication device. The transmission signal is transmitted by repeatedly arranging a plurality of different types of transmission information,
The control means controls the transmission mode of the transmission signal by adjusting the transmission frequency of each of the plurality of types of transmission information according to the priority set for each of the plurality of types of transmission information. The roadside communication apparatus as described in any one of -6. The transmission signal is transmitted by repeatedly arranging a plurality of different types of transmission information,
The said control means controls the transmission aspect of the said transmission signal by adjusting the transmission frequency of each of the said multiple types of transmission information according to the data size of each of the said multiple types of transmission information. The roadside communication apparatus as described in any one of Claims. A storage means for storing a database for controlling a transmission mode of the transmission signal based on the inhibition information;
The roadside communication device according to any one of claims 1 to 8, wherein the control unit controls a transmission mode of a transmission signal by the transmission unit based on the database. A road-to-vehicle communication system including a mobile communication device mounted on a vehicle and a roadside communication device that performs road-to-vehicle communication with the mobile communication device,
The roadside communication device is
Transmitting means for transmitting a transmission signal to the mobile communication device;
An acquisition means for acquiring inhibition information related to a transmission inhibition factor of the transmission signal;
A road-to-vehicle communication system comprising: a control unit that controls a transmission mode of the transmission signal by the transmission unit based on the inhibition information acquired by the acquisition unit.

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