WO2014192264A1

WO2014192264A1 - Vehicle-mounted communication device

Info

Publication number: WO2014192264A1
Application number: PCT/JP2014/002694
Authority: WO
Inventors: 宜隆平尾
Original assignee: 株式会社デンソー
Priority date: 2013-05-30
Filing date: 2014-05-22
Publication date: 2014-12-04
Also published as: JP2014232499A

Abstract

In a transmission control process performed by a vehicle-mounted communication device in a primary vehicle, the reception strength of an incoming signal transmitted by a communication counterparty, namely another vehicle-mounted communication device, is detected. If and only if said reception strength falls below a preset first strength threshold ("YES" at S130), a wireless information signal containing vehicle-status information that indicates the current status of the primary vehicle is transmitted (S140) via a medium-range wireless communication unit. That is, the lower the reception strength of the incoming transmitted signal, the larger the distance between the primary vehicle and the other vehicle, and when said distance is large, the current status of the other vehicle can be conveyed to the driver of the primary vehicle.

Description

In-vehicle communication device

Cross-reference of related applications

This disclosure is based on Japanese Patent Application No. 2013-114123 filed on May 30, 2013, the contents of which are incorporated herein.

The present disclosure relates to an in-vehicle communication device that transmits and receives a wireless information signal for sharing information between users.

Conventionally, for the purpose of comfortably carrying out group traveling in which a plurality of users drive different vehicles and travel toward a destination, various information such as information on destinations and information that matches hobbies and preferences, etc. In-vehicle communication devices that transmit and receive wireless information signals for sharing information on each other have been proposed.

In a vehicle-to-vehicle communication system configured by mounting this type of in-vehicle communication device in each vehicle for each user, all in-vehicle communication devices are used as base stations for mobile communication networks in order to avoid congestion of communication traffic. It is considered that a configuration in which wireless information signals are transmitted and received using medium-distance wireless communication such as WiFi direct is more preferable than connecting to a network via a network.

Generally, in such a vehicle-to-vehicle communication system, each in-vehicle communication device transmits and receives a wireless information signal including position information indicating the current position of the vehicle, and displays the current position of the main vehicle along with the current position of the main vehicle. In addition, the merge point where the main vehicle and other vehicles meet is calculated based on the position information, and the positional relationship of each vehicle is displayed when the main vehicle reaches this merge point. The thing to do is also considered (for example, refer patent document 1).

JP 2012-112889 A

However, in the conventional inter-vehicle communication system, each in-vehicle communication device must periodically transmit and receive a wireless information signal including position information in order to calculate a junction, for example, information on destinations and hobbies / preferences. There is a concern that communication may be interrupted or delayed when users share other information such as information that matches.

This disclosure has been made in view of the above-described concerns and the like, and an object thereof is to provide an in-vehicle communication device that enables group traveling more comfortably.

In order to achieve the above object, according to one example of the present disclosure, an in-vehicle communication device is mounted on a vehicle, and at least one other in-vehicle communication device mounted on another vehicle is in the middle. By performing the distance wireless communication, the wireless information signal for sharing information between users is transmitted and received, and a reception intensity detection section and a transmission control section are provided.

In this structure, the reception strength detection section detects the reception strength of signals transmitted from other in-vehicle communication devices, and the transmission control section is preset with the reception strength detected by the reception strength detection section. Only when the intensity falls below the first threshold intensity, the wireless information signal including the vehicle status information indicating the current status of the vehicle is transmitted.

In other words, in this configuration, the lower the reception intensity of the signal transmitted from the other in-vehicle communication device, the greater the distance between the main vehicle and the other vehicle, so when this distance increases, If the current situation can be communicated to the driver of the main vehicle, it is not necessary for users to periodically send and receive vehicle status information such as position information in a wireless information signal for sharing various information. Pay attention.

The inter-vehicle communication system configured by mounting the in-vehicle communication device of this configuration on each vehicle for each user is often used when each user travels toward the same destination while paying attention to each other's position. Used. For this reason, each user can obtain the vehicle status of the other vehicle only when the other vehicle is far away from the main vehicle even if the vehicle status information of the other vehicle is not transmitted when the other vehicle exists around the main vehicle. If the information is transmitted, it is possible to perform an action (for example, driving such that the other vehicle approaches the main vehicle) according to the current situation of the other vehicle at that time.

Therefore, according to this configuration, only when it is really necessary, it transmits and receives wireless information signals including vehicle status information, otherwise, for example, information on destinations, information that matches hobbies / preferences, etc. Wireless information signals can be transmitted and received between users for the purpose of sharing other information, and group traveling can be performed more comfortably.

The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description with reference to the accompanying drawings.
It is a block diagram illustrating the configuration of an in-vehicle communication device, It is a flowchart which illustrates a transmission control process.

Hereinafter, an in-vehicle communication device as an embodiment of the present disclosure will be described with reference to the drawings. Note that the in-vehicle communication device of the present embodiment is mounted on each user's vehicle for the purpose of performing group traveling such that a plurality of users drive different vehicles and travel toward a destination, for example. A device that transmits and receives wireless information signals necessary for users to share various types of information such as information on destinations and information that matches hobbies and preferences.

In the following description, an in-vehicle communication device mounted on a user's vehicle (hereinafter referred to as a main vehicle) is referred to as a main in-vehicle communication device 10, and another user's vehicle (hereinafter referred to as another vehicle) in a group to which the user belongs. The other in-vehicle communication device mounted in the above is referred to as a sub-in-vehicle communication device 20. In the present embodiment, it is assumed that the main in-vehicle communication device 10 and the sub in-vehicle communication device 20 have the same configuration (the same function). A vehicle equipped with an in-vehicle communication device is also referred to as a host vehicle. That is, the main vehicle and other vehicles correspond to the host vehicle.

<Overall configuration>
As shown in FIG. 1, the main in-vehicle communication device 10 of the present embodiment includes a wireless communication unit 11 that performs wireless communication with the outside of the main vehicle in which the main in-vehicle communication device 10 is mounted, and the speed of the main vehicle (main vehicle speed). ) Detecting the vehicle speed sensor unit 12, the operation input unit 13 for inputting the operation content by the user, the voice input unit 14 for inputting the uttered voice by the user, and the main control circuit 15 connected to these units 11 to 14. It has. In the main in-vehicle communication device 10, the main control circuit 15 is connected to the audio device 30 and the navigation device 40 mounted on the main vehicle.

The navigation device 40 displays map data around the current position of the main vehicle among the map data stored in a medium such as a hard disk, and superimposes the current position of the main vehicle and facility information (for example, the position of the facility) on the map data. A display 40 a for displaying, a navigation control circuit 40 b connected to the main control circuit 15 for executing various processes, and a speaker 30 a shared with the audio device 30.

The navigation control circuit 40b is configured around a known microcomputer. For example, the CPU uses a RAM as a work area based on a program stored in the ROM, and performs general navigation processing and a main control circuit. The first and second main-navigation control processes based on the control command from 15 are executed.

The general navigation process is to calculate an optimum route from the current position of the main vehicle based on a detection signal of a known GPS (Global Posting System) receiver or the like to a destination designated by the user, This is a process of performing route guidance or the like via 40a or the speaker 30a.

The first main-navigation control process is based on data (hereinafter referred to as “external data”) input from the outside of the navigation control circuit 40b in accordance with a first control command to be described later from the main control circuit 15. And an image such as a still image are displayed on the display 40a, and voices or the like of other users are output from the speaker 30a.

Further, the second main-navigation control process is based on the external data in accordance with a later-described second control command from the main control circuit 15, and the current position of the other vehicle is superimposed on the map data, Processing such as outputting a message or warning sound from the speaker 30a indicating the situation (the current position of the other vehicle, the current traveling speed, the current situation around the other vehicle (the presence of traffic jams, the state of the traffic light, etc.)) It is.

The audio device 30 outputs audio of AM / FM broadcast received by the AM / FM radio tuner, audio of TV broadcast received by the TV tuner, music such as music read from a CD / DVD player, hard disk, or the like. The speaker 30 a, an audio control circuit 30 b that is connected to the main control circuit 15 and executes various processes, and a display 40 a that is shared with the navigation device 40 are configured.

The audio control circuit 30b is configured around a known microcomputer. For example, the CPU uses a RAM as a work area based on a program stored in the ROM, and performs general audio visual (AV) processing, Then, main-AV control processing based on a control command from the main control circuit 15 is executed.

Note that general audiovisual processing means that audio such as AM / FM broadcast, TV broadcast, and music specified by the user is output from the speaker 30a, TV broadcast, DVD, video on a hard disk, still image, etc. For example, an image is displayed on the display 40a.

Also, the main-AV control process is to output audio such as AM / FM broadcast, TV broadcast, and music specified by the control command from the main control circuit 15 from the speaker 30a, TV broadcast, DVD, on the hard disk. This is a process of displaying an image such as a moving image or a still image on the display 40a.

The voice input unit 14 performs a process of converting a voltage signal into voice data based on an input voltage from a microphone that collects sound around the sound, and inputs the voice data generated by this process to the main control circuit 15. is there.

For example, the operation input unit 13 detects a pressing operation (pressing operation with a finger, a pen, or the like) on the image display surface of the display 40a by the user, and detects a position on the image display surface where the pressing operation is performed. These are configured by mechanical switches or the like, and input operation contents corresponding to a pressing operation by the user or the like to the main control circuit 15.

In addition, as operation content by a user, the thing for setting the sub vehicle-mounted communication apparatus 20 mounted in the other vehicle different from the main vehicle of the member (other users) at the time of carrying out this group traveling as a communication partner, And the like for setting information shared between users (hereinafter referred to as “shared information”).

The wireless communication unit 11 performs medium-range wireless communication between the base station communication unit 11a connected to the base station in the communication area that covers the position of the main in-vehicle communication device 10 via the antenna and the outside of the main vehicle. This is a wireless LAN device configured to include a mid-range wireless communication unit 11b for performing.

The base station communication unit 11a receives various contents designated by the user from the server, for example, by downloading and uploading various data to and from a server on the WEB via the Internet network connected to the base station. It is possible to do.

The medium-range wireless communication unit 11b uses the existing wireless LAN technology as it is with respect to the communication method, encryption, etc., and uses the technology (WiFi Direct) that gives the wireless communication unit 11 (wireless LAN device) a function as an access point. Various signals such as wireless information signals can be transmitted to and received from one to a plurality of sub vehicle-mounted communication devices 20 located within a distance range of about several tens to several hundreds of meters.

The main control circuit 15 is configured around a well-known microcomputer. For example, the CPU executes various processes using the RAM as a work area based on programs and applications stored in the ROM. . The applications include those provided from a server on the WEB. For example, voice (voice data) is encoded and compressed by VoIP (Voice over Internet Protocol) and converted into packets on the IP network. This includes a call function for transmitting in real time, a moving image reproduction function for reproducing a moving image transferred from a moving image site on the WEB, a general mail function, a chat function, and the like.

Functionally, the main control circuit 15 performs a reception intensity detection section 15a for detecting the intensity (reception intensity) of a signal received via the intermediate-range wireless communication unit 11b, and transmission control and reception control of various signals. The communication control section 15b to perform and the signal transmission section 15c which transmits various signals according to the command from the communication control section 15b are comprised. It can also be said that the communication control section 15b and the signal transmission section 15c function as a transmission control section.

When there is no specific command from the communication control section 15b, the signal transmission section 15c generates transmission information indicating the command, voice data, character data, and the like based on the shared information set via the operation input unit 13. In addition, it is configured to transmit to the sub in-vehicle communication device 20 which is one or a plurality of communication partners set via the operation input unit 13 via the mid-range wireless communication unit 11b.

As shared information, among the functions realized by the above applications, voice data input from the voice input unit 14 by the call function, video data input from the base station by the video playback function, mail function, chat Examples thereof include character data input from the operation input unit 13 according to functions and various data that can be acquired from the audio device 30.

In addition, the wireless information signal may be the shared information itself or a command for acquiring the shared information. As the latter command, the same moving image data as the shared information is acquired (reproduced) by the moving image reproducing function of the sub in-vehicle communication device 20, or the same data (image) as the shared information from the audio device 30 included in the sub in-vehicle communication device 20. And audio).

<Communication control processing>
Here, the process (communication control process) executed by the communication control section 15b will be described with reference to the flowchart of FIG. Note that this processing is performed, for example, with vehicle-to-vehicle communication (medium-range wireless communication) performed via the mid-range wireless communication unit 11b with the sub-vehicle communication apparatus 20 that is one or more communication partners via the operation input unit 13. It starts when communication is established.

Here, the flowchart described in this application or the processing of the flowchart is configured by a plurality of sections (or referred to as steps), and each section is expressed as S110, for example. Furthermore, each section can be divided into a plurality of subsections, while a plurality of sections can be combined into one section. Further, each section configured in this manner can be referred to as a device, module, or means. In addition, each of the above sections or a combination thereof includes not only (i) a section of software combined with a hardware unit (eg, a computer), but also (ii) hardware (eg, an integrated circuit, As a section of (wiring logic circuit), it can be realized with or without the function of related devices. Furthermore, the hardware section can be configured inside the microcomputer.

When this process is started, the communication control section 15b determines whether or not a radio signal is received from the sub in-vehicle communication device 20 via the intermediate-range wireless communication unit 11b in S110, and when an affirmative determination is made here The process proceeds to S120, and if a negative determination is made, the process proceeds to S130.

In S120, various processes (reception information processing) are performed according to the information included in the wireless signal received in S110, and the process proceeds to S130.

Specifically, when a wireless information signal is received in S110 and the wireless information signal includes the above-described command, voice data, image data, character data, etc., the first information is used as external data. A first control command for causing the navigation control circuit 40b to execute main-navigation control processing is output. Further, when the wireless information signal includes vehicle status information (described later) indicating the current status of the vehicle on which the sub in-vehicle communication device 20 that is the transmission source is mounted, the vehicle status information is stored as external data. As a result, a second control command for causing the navigation control circuit 40b to execute the second main-navigation control process is output.

The navigation control circuit 40b, which has received the first control command from the communication control section 15b, executes the first main-navigation control process based on the external data, thereby displaying an image such as a moving image or a still image on the display 40a. For example, it is possible to display, or to output speech uttered by other users, sound, music, or sound linked to a moving image from the speaker 30a.

In addition, the navigation control circuit 40b, which has received the second control command from the communication control section 15b, executes the second main-navigation control process based on the external data, thereby superimposing and displaying the current position of the other vehicle on the map data. Or a message or warning sound from the speaker 30a indicating the current status of the other vehicle (current position of the other vehicle, current traveling speed, current status of the surrounding of the other vehicle (presence of traffic jam, traffic light status, etc.)) Will be output.

When the first radio control information (described later) is received in S110, transmission of a radio detection signal (described later) in S210 at the subsequent stage is stopped, and second radio control information (described later) is performed in S110. Is received, transmission control for shortening the transmission cycle of the radio detection signal in S210 in the subsequent stage is performed.

Next, in S130, it is determined whether or not the reception strength detected by the reception strength detection section 15a is lower than a preset first threshold strength. If an affirmative determination is made here, the process proceeds to S140. If a negative determination is made, the process proceeds to S150. Note that the first threshold intensity is, for example, an intensity at which vehicle-to-vehicle communication can be performed, but is set in advance as an intensity at which the possibility that communication is interrupted increases below this intensity.

In S140, vehicle status information indicating the current status of the main vehicle is acquired from the navigation control circuit 40b and the vehicle speed sensor unit 12, and this vehicle status information is output to the signal transmission section 15c. When this information is input, the signal transmission section 15c transmits a wireless information signal including vehicle status information via the medium distance wireless communication unit 11b.

The vehicle status information includes, for example, position information indicating the current position of the main vehicle, speed information indicating the current traveling speed, road information (congestion information and traffic signal information) indicating the situation around the current vehicle, and the like. Can be mentioned. Incidentally, traffic jam information and traffic signal information can be acquired by road-to-vehicle communication performed with, for example, a roadside machine installed on the roadside.

On the other hand, in S150, the amount of change in the reception intensity detected by the reception intensity detection section 15a is measured. For example, by acquiring a sampling value indicating the reception intensity from the reception intensity detection section 15a and continuously storing the difference value between the current acquisition and the previous acquisition for the sampling value in the RAM, Monitor the amount of change. It can be said that S150 also functions as a reception change amount measurement section.

In the subsequent S160, it is determined whether or not the reception strength detected by the reception strength detection section 15a has decreased based on the measurement result in S150. If an affirmative determination is made here, the process proceeds to S170 and a negative determination is made. In the case, the process proceeds to S190.

In S170, it is determined whether or not the change amount of the reception intensity measured in S150 exceeds a preset reception threshold change amount. If an affirmative determination is made here, the process proceeds to S180 and a negative determination is made. In the case, the process proceeds to S190. The reception threshold change amount is a threshold set in advance for detecting a sudden change in reception intensity.

In S180, the first threshold intensity described above is variably set to a value larger than the initial value, while in S190, the first threshold intensity is reset to the initial value. That is, in S160 to S190, processing for variably setting the first threshold intensity is performed according to the reception intensity and the amount of change. It can be said that S160 to S190 function as a threshold intensity setting section. Specifically, in this embodiment, when the reception strength of a signal transmitted from another in-vehicle communication device is rapidly reduced, the wireless information including the vehicle status information is increased by increasing the first threshold strength. When the signal transmission timing is advanced and there is no such change in reception intensity, the first threshold intensity is reset to return to the timing based on the initial value.

In subsequent S200, it is determined whether or not the reception intensity detected by the reception intensity detection section 15a is lower than a preset second threshold intensity. If an affirmative determination is made here, the process proceeds to S210 and a negative determination is made. If so, the process returns to S110. Note that the second threshold strength is a value that is at least larger than the first threshold strength, so that the first threshold strength has a margin time in which vehicle-to-vehicle communication can be performed stably. Is set in advance.

Then, in S210, a radio detection signal transmission command prepared separately from the radio information signal described above is output to the signal transmission section 15c in order to increase the detection frequency of the reception intensity in the sub in-vehicle communication device 20 that is the communication partner. . When this transmission command is input, the signal transmission section 15c transmits a wireless detection signal via the medium distance wireless communication unit 11b according to the transmission command. In addition, a radio detection signal is also sent from the sub-vehicle communication apparatus 20 that is the communication partner.

In subsequent S220, it is determined whether or not the reception intensity detection frequency by the reception intensity detection section 15a is higher than a preset threshold frequency. If an affirmative determination is made here, the process proceeds to S230 and a negative determination is made. In the case, the process proceeds to S240. The reception intensity detection frequency can be obtained from the number of times a sampling value indicating the reception intensity is acquired in a predetermined time. The threshold frequency is a value set in advance to maintain the accuracy of the threshold determination using the first threshold strength in S130 and the threshold determination using the second threshold strength in S200 in a good state. .

In S230, a first radio control signal indicating that transmission of a radio detection signal from the sub-vehicle communication apparatus 20 that is a communication partner is unnecessary is transmitted, and the process returns to S110. In addition, the sub vehicle-mounted communication apparatus 20 which received the 1st radio | wireless control signal implements transmission control which stops transmission of the radio | wireless detection signal in S210 as mentioned above.

On the other hand, in S240, the amount of change in the speed of the main vehicle (main vehicle speed) is measured based on the detection result by the vehicle speed sensor unit 12. For example, by acquiring a sampling value indicating the main vehicle speed from the vehicle speed sensor unit 12, and continuously storing the difference value between the current acquisition amount and the previous acquisition amount for this sampling value in the RAM, the change in the main vehicle speed along the time series Monitor the amount. It can be said that S240 also functions as a speed change amount measurement section.

In subsequent S250, it is determined whether or not the change amount of the main vehicle speed measured in S240 exceeds a preset speed threshold change amount. If an affirmative determination is made here, the process proceeds to S260 and a negative determination is made. Return to S110. The speed threshold change amount is a threshold set in advance for detecting a sudden change in the main vehicle speed.

Finally, in S260, a second radio control signal indicating that it is necessary to reduce the transmission interval of the radio detection signal by the sub in-vehicle communication device 20 that is the communication partner is transmitted, and the process returns to S110. In addition, the sub vehicle-mounted communication apparatus 20 which received the 2nd radio | wireless control signal implements transmission control which shortens the transmission cycle of the radio | wireless detection signal in S210 as mentioned above.

<Effect>
As described above, in the transmission control process, the reception intensity of the signal transmitted from the sub in-vehicle communication device 20 is detected, and the reception intensity detected by the reception intensity detection section 15a is the first threshold intensity set in advance. The radio information signal including the vehicle status information indicating the current status of the main vehicle is transmitted only when the value is less than.

That is, the lower the reception intensity of the signal transmitted from the sub in-vehicle communication device 20, the greater the distance between the main vehicle and the other vehicle. When this distance increases, the current state of the other vehicle is determined as the main vehicle. If it can be communicated to the driver, it is unnecessary to periodically transmit and receive vehicle status information such as position information in a wireless information signal for sharing various types of information between users.

Therefore, each user can obtain the vehicle status information of the other vehicle only when the other vehicle is far away from the main vehicle even if the vehicle status information of the other vehicle is not transmitted when the other vehicle exists around the main vehicle. Is transmitted, it becomes possible to take action according to the current situation of the other vehicle at that time (for example, driving such that the other vehicle approaches the main vehicle).

Therefore, according to the in-

vehicle communication devices

10 and 20, only when it is really necessary, the wireless information signal including the vehicle status information is transmitted / received. Wireless information signals can be transmitted and received for the purpose of sharing other information between users, such as information to be performed, and group traveling can be performed more comfortably.

Also, in the transmission control process, the amount of change in reception strength detected by the reception strength detection section 15a is measured, and the first threshold strength is variably set according to the amount of change in reception strength. Specifically, when the reception strength of the signal transmitted from the sub in-vehicle communication device 20 rapidly decreases, the timing at which the wireless information signal including the vehicle status information is transmitted by increasing the first threshold strength Can be made faster. Thereby, before communication with the sub vehicle-mounted communication apparatus 20 stops, the certainty which transmits the present condition of the main vehicle to the user of another vehicle can be raised.

Further, in the transmission control process, when the reception intensity detected by the reception intensity detection section 15a falls below the second threshold intensity set in advance as a value larger than the first threshold intensity, the sub in-vehicle communication device 20 receives the reception intensity. A wireless detection signal for increasing the frequency of detection is transmitted.

For this reason, even when the reception frequency of the wireless information signal decreases when the reception strength of the wireless information signal transmitted from the sub in-vehicle communication device 20 decreases, the decrease is the amount of the wireless detection signal. Since it is compensated by the increase in the reception frequency, the accuracy of the threshold determination using the first threshold intensity can be increased. Thereby, the precision of the timing which transmits a radio | wireless information signal including vehicle condition information can also be raised.

Further, in the transmission control process, when the reception intensity detection frequency by the reception intensity detection section 15a is higher than a preset threshold frequency, it indicates that the transmission of the wireless detection signal from the sub in-vehicle communication device 20 is unnecessary. A first radio control signal is transmitted.

Thereby, when the reception intensity of the radio information signal transmitted from the sub in-vehicle communication device 20 is lowered, and the reception frequency of the radio information signal is sufficiently high, the threshold determination using the first threshold intensity Therefore, it is possible to avoid unnecessary transmission / reception of a wireless detection signal, and thus to prevent the sharing of information between users.

Further, in the transmission control process, when the speed change amount of the main vehicle is measured and the speed change amount of the vehicle exceeds a preset speed threshold change amount during reception of the wireless detection signal, A second radio control signal indicating that it is necessary to reduce the transmission interval of the radio detection signal by the sub in-vehicle communication device 20 is transmitted.

Thereby, when the reception intensity of the wireless information signal transmitted from the sub in-vehicle communication device 20 is reduced, the distance between the main vehicle and the other vehicle may be greatly separated if the speed of the main vehicle changes suddenly. Therefore, the accuracy of the threshold determination using the first threshold strength can be further increased by shortening the transmission interval of the wireless detection signal from the sub in-vehicle communication device 20. Thereby, even when the speed of the main vehicle is suddenly changed, it is possible to increase the certainty of transmitting the current state of the main vehicle to the user of the other vehicle before the communication with the sub in-vehicle communication device 20 is interrupted. .

<Other embodiments>
As mentioned above, although embodiment of this indication was described, this indication is not limited to the above-mentioned embodiment, and can be carried out in various modes in the range which does not deviate from the gist of this indication.

For example, in the transmission control process of the above embodiment, when the reception intensity of the signal transmitted from the sub in-vehicle communication device 20 rapidly decreases, the first threshold intensity is increased, but the present invention is limited to this. Instead, when the reception strength suddenly increases, the first threshold strength may be variably set according to the amount of change in the reception strength, such as decreasing the first threshold strength.

Moreover, in the main vehicle-mounted communication apparatus 10 of the said embodiment, although it is comprised so that a radio signal may be transmitted / received between the sub vehicle-mounted communication apparatuses 20 by WiFi direct, it is not limited to this, For example, WiFi direct Instead, the ad hoc mode of WiFi may be used, or other medium-range wireless communication technologies such as Bluetooth (TM) may be used.

In addition, although the sub vehicle-mounted communication apparatus 20 of the said embodiment was taken as the same structure as the main vehicle-mounted communication apparatus 10, it is not limited to this, For example, in the transmission control process, it received from the main vehicle-mounted communication apparatus 10 You may be comprised so that various transmission control may be performed according to the command (The command for the main vehicle-mounted communication apparatus 10 to perform the same transmission control to the sub vehicle-mounted communication apparatus 20) contained in various signals.

Although the present disclosure has been described based on the embodiments, it is understood that the present disclosure is not limited to the embodiments and structures. The present disclosure includes various modifications and modifications within the equivalent range. In addition, various combinations and forms, as well as other combinations and forms including only one element, more or less, are within the scope and spirit of the present disclosure.

Claims

By performing medium-range wireless communication with another vehicle-mounted communication device (20) that is mounted on a vehicle and mounted on at least one other vehicle different from the vehicle and set in advance, the user can An in-vehicle communication device (10) for transmitting and receiving wireless information signals for sharing information with each other,
A reception intensity detection section (15a) for detecting the reception intensity of a signal transmitted from the other in-vehicle communication device;
A transmission control section that transmits the radio information signal including vehicle status information indicating the current status of the vehicle only when the received strength detected by the received strength detection section is lower than a preset first threshold strength. (15b, 15c),
An in-vehicle communication device.
A reception change amount measurement section (S150) for measuring a change amount of the reception intensity detected by the reception intensity detection section;
A threshold strength setting section (S160-S190) for variably setting the first threshold strength according to the amount of change in the reception strength measured by the reception variation measurement section;
The in-vehicle communication device according to claim 1, comprising:
When the reception strength detected by the reception strength detection section falls below a second threshold strength set in advance as a value larger than the first threshold strength, the other transmission control section The in-vehicle communication device according to claim 1 or 2, wherein a radio detection signal for increasing the detection frequency of the reception intensity is transmitted.
The transmission control section indicates that transmission of the wireless detection signal from the other in-vehicle communication device is unnecessary when the detection frequency of the reception intensity by the reception intensity detection section is higher than a preset threshold frequency. The in-vehicle communication device according to claim 3 which transmits the 1st radio control signal which shows.
A speed change amount measuring section (S240) for measuring a change in speed of the vehicle;
The transmission control section changes a speed change amount of the vehicle exceeding a preset speed threshold change amount based on a measurement result of the speed change amount measurement section while receiving the wireless detection signal. 5. The in-vehicle communication device according to claim 3, wherein the second in-vehicle communication device transmits a second radio control signal indicating that the transmission interval of the wireless detection signal needs to be reduced by the other in-vehicle communication device.