JP7738807B2 - In-vehicle communication device - Google Patents

Description

This disclosure relates to an in-vehicle communication device.

In recent years, technologies related to vehicle-to-vehicle communication and road-to-vehicle communication have been developed with the aim of preventing traffic accidents and easing congestion. In vehicle-to-vehicle communication, each vehicle broadcasts its own vehicle information to those around it, thereby supporting vehicle-to-vehicle safety. There is also technology that broadcasts information about surrounding objects detected by sensors installed in vehicles as V2X (Vehicle to X) messages to those around it, allowing vehicles that receive these messages to recognize the presence of surrounding vehicles that they themselves have not been able to detect.

Furthermore, in vehicle-to-vehicle communications, when there are many vehicles in the vicinity, the load on message reception processing is high. However, there are situations where it is not necessary to receive messages from all vehicles. For example, when using an alarm application that assists in collision avoidance, it is not necessarily necessary to receive messages from vehicles with a low risk of collision.

A known technique for reducing the processing load of received messages is to determine the importance of the received message, determine whether verification is necessary based on that importance, and then verify messages that are determined to require verification (see, for example, Patent Document 1). According to the technology disclosed in Patent Document 1, the importance of a received message is determined based on the position and speed of other vehicles, the packet type flag attached to the message, the frequency of reception from the same sender, the received power, and other factors. Furthermore, messages that are determined not to require verification are not verified, thereby reducing the processing load.

JP 2012-100024 A

Vehicles are not necessarily equipped with onboard devices capable of V2X communication (hereinafter referred to as V2X onboard devices). Therefore, for vehicles without V2X onboard devices, information transmitted from vehicles equipped with sensors capable of recognizing surrounding objects is important. Patent Document 1 determines the importance of a message based on the location or proximity of the transmitting vehicle. However, even if the transmitting vehicle is located far away and detects a vehicle without a V2X onboard device that is close to the transmitting vehicle, the message from the transmitting vehicle may be judged to be of low importance. However, information from vehicles without a V2X onboard device that are close to the transmitting vehicle is important to the transmitting vehicle. Thus, there is a possibility that a message from a vehicle that should have been received may be overlooked.

This disclosure discloses technology to solve the above-mentioned problems, and aims to provide an in-vehicle communication device that can appropriately set the importance of messages sent from other vehicles and prevent messages that are important to the vehicle from being overlooked.

The in-vehicle communication device of the present disclosure includes:
The vehicle information receiving unit receives other vehicle information from other vehicles via vehicle-to-vehicle communication, including the vehicle state including the position of the other vehicle and surrounding object detection information that detects objects around the other vehicle, and an importance determination unit determines the importance of the other vehicle based on the received surrounding object detection information.

This disclosure makes it possible to provide an in-vehicle communication device that can appropriately set the importance of messages sent from other vehicles, thereby preventing messages that are important to the vehicle from being overlooked.

1 is a diagram illustrating a configuration of an inter-vehicle communication system according to a first embodiment. 1 is a functional block diagram showing a configuration of an in-vehicle communication device according to a first embodiment; 1 is a diagram illustrating an example of a hardware configuration of an in-vehicle communication device according to a first embodiment; FIG. 2 is a diagram illustrating an example of a sensor mounted on a vehicle. 4 is a flowchart for explaining the operation of the in-vehicle communication device according to the first embodiment. 10 is a flowchart illustrating a procedure for determining importance according to the first embodiment.

The following describes an embodiment of the disclosed in-vehicle communication device with reference to the drawings. Note that in each drawing, the same reference numerals indicate the same or corresponding parts. Therefore, detailed descriptions of these parts may be omitted to avoid duplication.

Embodiment 1.
The in-vehicle communication device according to the first embodiment will be described below with reference to the drawings.
FIG. 1 is a diagram showing the configuration of a vehicle-to-vehicle communication system in which communication is performed between vehicles equipped with an on-vehicle communication device 1 according to a first embodiment. In FIG. 1 , a host vehicle OV is equipped with the on-vehicle communication device 1, and multiple other vehicles VE1, ..., VEn (n is a natural number, and the other vehicles are collectively referred to as other vehicles VE) are also equipped with on-vehicle communication devices 1. Here, n is the number of vehicles equipped with on-vehicle communication devices 1 that exist within an area in which vehicle-to-vehicle communication is possible with the host vehicle OV. The other vehicle VE2 in FIG. 1 is equipped with an object detection sensor 2 that detects objects around the vehicle, as described below. Furthermore, as described below, the other vehicles VE can also acquire information about surrounding objects detected by a roadside unit 5 from the roadside unit 5.

<Configuration of in-vehicle communication device 1>
Next, we will explain the configuration of the in-vehicle communication device 1. The in-vehicle communication device 1 has the functions of transmitting messages including vehicle information about the host vehicle OV to other surrounding vehicles VE via wireless communication, receiving messages including information about the vehicle status of the other vehicles VE from the other vehicles VE, and acquiring information necessary for the traveling of the host vehicle OV based on the information about the other vehicles VE included in the received messages.

Figure 2 is a functional block diagram showing the configuration of an in-vehicle communication device according to embodiment 1. The in-vehicle communication device 1 includes a communication unit 10 that performs wireless communication with other vehicles VE, an other vehicle information receiving unit 20 that acquires vehicle information about other vehicles VE around the host vehicle from messages received by the communication unit 10, an importance determination unit 30 that determines the importance of the sending vehicle based on the information acquired by the other vehicle information receiving unit 20, an application unit 40 that executes a driving assistance application according to the importance, and a display unit 50 that displays the content executed by the application unit 40.

The communication unit 10 transmits and receives messages to and from the outside of the vehicle using, for example, short-range wireless communication using a dedicated frequency for vehicle-to-vehicle communication, or communication means compliant with 4G or 5G (5th Generation; fifth generation mobile communication system). Note that connections within the vehicle are made using, for example, CAN (Control Area Network: registered trademark).

The other vehicle information receiving unit 20 outputs messages including the vehicle status of other vehicles VE received by the communication unit 10 to the importance determination unit 30, and determines whether to process the received message depending on the importance set for the sending vehicle VE. If it determines to process the message, it decodes the message and obtains vehicle information such as the position, speed, and direction of other vehicles VE around the vehicle. The obtained vehicle information of other vehicles VE is output to the application unit 40. Note that the message also includes information such as surrounding object detection information detected by sensors installed in each vehicle. Therefore, the other vehicle information receiving unit 20 also obtains this object detection information.

The importance determination unit 30 determines the importance of the other vehicle VE that sent the message based on the content of the received message. The determination of importance will be described later. The determined importance is output to the other vehicle information receiving unit 20.

The application unit 40 executes driving assistance applications related to the driving of the host vehicle OV based on information from other vehicles VE acquired by the other vehicle information receiving unit 20. The applications that are executed include, for example, an alarm application that determines the possibility of contact between the host vehicle and another vehicle and issues a warning to the driver, and an alarm application that issues a warning to the driver when the host vehicle passes through an intersection to protect vulnerable road users such as pedestrians and cyclists near the intersection. These applications are executed based on information from other vehicles VE acquired by the other vehicle information receiving unit 20.

The display unit 50 is a screen or an audio device that notifies the driver of the results of the application executed by the application unit 40. For example, it may display on the road other vehicles VE that may come into contact with the host vehicle OV in the future, or notify the driver of approaching pedestrians by audio.
The application unit 40 and the display unit 50 may not be included in the in-vehicle communication device 1 but may be provided outside the in-vehicle communication device 1 .

Figure 3 is a diagram showing an example of the hardware configuration of the in-vehicle communication device 1 according to embodiment 1. The in-vehicle communication device 1 includes a processor 101, a memory 102 as a main memory device, and an auxiliary memory device 103. The processor 101 is configured, for example, by a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), etc.

Memory 102 is composed of a volatile storage device such as random access memory, and auxiliary storage device 103 is composed of a non-volatile storage device such as flash memory or a hard disk. Auxiliary storage device 103 stores a predetermined program to be executed by processor 101, which reads and executes this program as appropriate to perform various arithmetic processing. At this time, the predetermined program is temporarily saved from auxiliary storage device 103 to memory 102, and processor 101 reads the program from memory 102. The arithmetic processing of each functional unit of in-vehicle communication device 1 according to embodiment 1 is realized by processor 101 executing a predetermined program as described above. The results of the arithmetic processing by processor 101 are temporarily stored in memory 102 and then stored in auxiliary storage device 103 according to the purpose of the executed arithmetic processing.

Furthermore, it is equipped with a transmitting device 104 and a receiving device 105 as communication modules for communicating with other vehicles VE.

Next, an example of a vehicle equipped with an object detection sensor for detecting objects around the vehicle will be described.
FIG. 4 shows an example of a vehicle equipped with a combination of object detection sensors, such as the other vehicle VE2 shown in FIG. 1 , and illustrates the detection ranges SN of each object detection sensor 2. In FIG. 4 , seven object detection sensors 2, 2a through 2g, are mounted on the vehicle, with three object detection sensors 2a, 2b, and 2g positioned in the front, two object detection sensors 2c and 2f positioned on the sides, and two object detection sensors 2d and 2e positioned in the rear. The detection ranges of each object detection sensor 2 are indicated by fan-shaped dashed lines, and objects can be detected within detection ranges SN1, SN2, and SN7 in the front, detection ranges SN3 and SN6 on the sides, and detection ranges SN4 and SN5 in the rear. While the number of object detection sensors 2 is not limited to seven, it is desirable to be able to set the object detection ranges to encompass the entire periphery of the vehicle.

The object detection sensor 2 detects object information around the vehicle. Objects around the vehicle include, for example, other vehicles, pedestrians, bicycles, motorcycles, and other traffic participants around the vehicle. The object detection sensor 2 is, for example, a camera, radar, LiDAR (Light Detection and Ranging), or sonar sensor installed on the vehicle. The object detection sensor 2 may output surrounding object detection information linked to the type of traffic participant, which may be classified as other vehicles, pedestrians, bicycles, motorcycles, etc.

The camera is installed in a position that allows it to capture images of the front, sides, and rear of the vehicle, and from the captured images it obtains information about the vehicle's environment, such as the lane and obstacles in front of the vehicle.

The radar emits radar light ahead of the vehicle and detects the reflected waves to measure the relative distance and relative speed of obstacles ahead of the vehicle, and outputs the measurement results.

LiDAR detects the position of an object by shining a laser around the vehicle and detecting the time difference between the light reflecting off the surrounding objects and returning.

Sonar sensors detect the location and distance of objects by emitting ultrasonic waves around the vehicle and detecting the time difference between the time it takes for the waves to reflect off nearby objects and return.

A vehicle equipped with such an object detection sensor 2 distributes surrounding object detection information including the position information of objects such as vehicles and pedestrians around the vehicle detected by the object detection sensor 2, along with a message containing the type of object detection sensor 2 used for detection.

A roadside unit 5 equipped with an object detection sensor 2 distributes surrounding object detection information, including the location information of objects such as vehicles and pedestrians around the roadside unit 5 detected by the object detection sensor 2, in a message.

Note that it is not necessary for all other vehicles around the subject vehicle to be equipped with these object detection sensors 2, and it is desirable for multiple vehicles to be equipped with these object detection sensors 2. In this embodiment, it is assumed that there is at least one other vehicle VE equipped with an object detection sensor 2 along with an in-vehicle communication device 1 within the area where vehicle-to-vehicle communication is performed. If the in-vehicle communication device 1 is equipped with an object detection sensor 2, peripheral object detection information around the vehicle will be added. Similarly, it is not necessary for all other vehicles around the subject vehicle to be equipped with communication means for acquiring peripheral object detection information from the roadside unit 5, but if peripheral information can be acquired from the roadside unit 5, peripheral object detection information around the vehicle will be added. The importance determination unit 30 determines the importance for each vehicle, including this peripheral object detection information.

<Operation of in-vehicle communication device 1>
Next, the operation of the in-vehicle communication device 1 will be described with reference to the flowchart of FIG.
First, in step S101, the communication unit 10 receives a message transmitted from another vehicle VE and outputs the message to the other vehicle information receiving unit 20. This operation is repeatedly performed at the timing when the communication unit 10 receives a message transmitted from another vehicle VE.

In step S102, the other vehicle information receiving unit 20 determines whether to process the received message. This determination is based on the importance level set for the vehicle that sent the message. The importance level is determined based on messages previously sent by the same vehicle. Importance levels can be divided into three levels, such as "high," "medium," and "low." If no importance level is set, it is determined that the message will be processed. Message processing involves obtaining vehicle information from the message for an application, extracting necessary information, and processing it. One method for determining the importance level of a message to process is, for example, based on the amount of messages stored in the message receiving buffer of the other vehicle information receiving unit. Criteria can be determined in advance, such as processing messages from "high" vehicles only if the amount of stored messages is 80% or more of the maximum buffer capacity. It is also possible to process messages from other vehicles for which a certain period of time has passed without messages being processed due to low importance, regardless of the level of importance.

If it is determined in step S102 that the message is to be processed (Yes in step S102), the process proceeds to step S103.
In step S103, the other vehicle information receiving unit 20 extracts information necessary for the application from the contents of the message transmitted from the other vehicle and outputs the information to the application unit 40. The application unit 40 executes processing according to the driving assistance application, and outputs the result and any necessary warnings to the display unit 50 to notify the driver.

In step S104, for messages that were determined to be processed in step S102, the importance determination unit 30 performs an importance determination to set the importance of each of the other vehicles VE that are the senders.

<Importance judgment>
Next, the procedure for determining the importance level in step S104 of Fig. 5 will be described with reference to the flowchart of Fig. 6. The importance level determination unit 30 determines the importance of a message received from another vehicle VE based on its content, and sets an importance level to determine whether future messages from similar vehicles should be given priority in processing. The importance level setting is not limited to the three levels described above.

First, in step S1041, the importance determination unit 30 acquires a message received from the other vehicle VE from the other vehicle information receiving unit 20.
In step S1042, it is determined whether the received message includes peripheral object detection information.

If the received message does not contain peripheral object detection information (No in step S1042), that is, if the message does not contain information about other vehicles other than the vehicle information of the sender vehicle VE, proceed to step S1043. In step S1043, the importance determination unit 30 determines the importance based on the positional relationship between the subject vehicle OV and the other vehicle VE. For example, if the distance between the subject vehicle OV and the other vehicle VE is short, the other vehicle VE itself may come into contact with the subject vehicle OV or their paths may interfere with each other, so the importance is determined to be "high." Furthermore, even if the distance between the subject vehicle OV and the other vehicle VE is not short, the importance may be set to "medium" or "high" depending on the direction and speed of the other vehicle VE.

In step S1042, if the received message includes surrounding object detection information (Yes in step S1042), that is, if the sending vehicle VE is a vehicle equipped with the object detection sensor 2 described in Figure 4 and the message includes surrounding object detection information acquired by the other vehicle VE around the other vehicle VE, proceed to step S1044.
In step S1044, the importance determination unit 30 analyzes the surrounding object detection information included in the message, and determines, as a result of the analysis, whether or not the detected object exists in the target area in which the host vehicle OV is traveling.

In step S1044, if it is determined that the detected object is not present in the target area in which the host vehicle OV is traveling (No in step S1044), the process proceeds to step S1045, and the importance of the other vehicle VE that sent the signal is determined to be "medium."
In step S1044, if it is determined that the detected object is present in the target area in which the host vehicle OV is traveling (Yes in step S1044), the process proceeds to step S1046, where the importance of the other vehicle VE that sent the signal is determined to be "high."

Here, an example of determining the importance level using peripheral object detection information from other vehicles VE will be described.
First, if the sending vehicle VE is a vehicle equipped with the object detection sensor 2 described in Figure 4 and sends a message including surrounding object detection information acquired by the other vehicle VE around the other vehicle VE, the importance of the sending vehicle VE is assigned to "medium" or higher.

(1) When the host vehicle OV executes the function of an alarm application related to intersection collisions or left turn assistance, it is very useful to know that a vehicle detected by an object detection sensor 2 mounted on another vehicle VE (a vehicle not detected by the host vehicle) is approaching within an area including the intersection when the host vehicle OV is approaching an intersection. In this way, when there is surrounding object detection information from another vehicle VE within the target area in which the host vehicle OV is traveling, the importance of the other vehicle VE that is the source of the information is determined to be "high."

(2) When the host vehicle OV executes the function of an alert application related to the protection of vulnerable road users, it is extremely useful to know that an object (pedestrian, bicycle) detected by the object detection sensor 2 mounted on another vehicle VE is approaching within an area including the intersection when the host vehicle OV is approaching an intersection. In this way, when there is surrounding object detection information from another vehicle VE within the target area in which the host vehicle OV is traveling, the importance of the other vehicle VE that is the source of the information is determined to be "high."

(3) In the case where the host vehicle OV veers into the oncoming lane to overtake a vehicle ahead, if the object detection sensor 2 mounted on the other vehicle VE detects a vehicle traveling in the opposite direction, the importance of the other vehicle VE, which is the source of the information, is determined to be "high."
The above three examples have been shown, but in step S1044, importance determination is performed based on whether or not the target area in which the host vehicle OV is traveling includes surrounding object detection information detected by the object detection sensor 2 mounted on the other vehicle VE.

The importance may also be determined according to the specifications of the object detection sensor 2 installed in the other vehicle VE. As mentioned above, there are multiple types of object detection sensors 2, and the situation will vary depending on whether a vehicle is equipped with one object detection sensor 2, multiple object detection sensors 2, or even multiple types of object detection sensors 2. For example, the importance of a vehicle that can obtain more accurate information based on criteria such as the detection range and detection accuracy of the object detection sensor 2, and the number of types of objects that can be detected may be determined to be higher.

When the host vehicle OV executes the function of an intersection collision or left turn assistance warning application, if information about a vehicle approaching the intersection is notified by messages from multiple other vehicles VE equipped with object detection sensors 2, it is better to prioritize the message from the vehicle with the sensor with the highest detection accuracy. This is because the higher the detection accuracy of the sensor, the more accurately the position of the vehicle approaching the intersection can be determined. For this reason, the sensors equipped on the other vehicles VE may be compared, and the importance of the vehicle with the more accurate sensor may be determined to be higher.

Furthermore, the importance may be determined to be high when another vehicle VE obtains surrounding object detection information from the roadside unit 5 and distributes that information in a message. In this case, the importance may be set taking into consideration the installation location information of the roadside unit 5. The target for determining the importance is not limited to vehicles, but may also be a roadside unit.

As described above, according to the first embodiment, the in-vehicle communication device 1 includes the other-vehicle information receiving unit 20 that receives, via vehicle-to-vehicle communication, vehicle status information, including the location of the other vehicle VE, and peripheral object detection information, which detects objects around the other vehicle VE, as other-vehicle information. The importance determining unit 30 determines the importance of the other vehicle VE based on the received peripheral object detection information. Therefore, by determining the importance based on whether the other vehicle VE is transmitting peripheral object detection information and whether the detected object has an impact on the host vehicle OV, messages from the other vehicle VE are not overlooked, even if the other vehicle VE is located far away and the possibility of contact with the other vehicle VE is low. Furthermore, the in-vehicle communication device 1 includes the application unit 40 that executes a driving assistance application using the vehicle status and peripheral object detection information from the other vehicle VE according to the importance determined by the importance determining unit 30. This allows the driving assistance application to execute the vehicle status and peripheral object detection information from the other vehicle according to the importance, thereby preventing an increase in processing load. Furthermore, by executing the driving assistance application using the necessary information, the operation of the driving assistance application is further improved.

In addition, since surrounding object detection information from other vehicles includes object position information, it is possible to determine the importance of other vehicles based on the position of the object detected by the other vehicle and the position of the vehicle itself, taking into account their impact on the vehicle itself, thereby improving the accuracy of importance determination.

In addition, other vehicles are equipped with object detection sensors that detect surrounding objects, and the information about detected surrounding objects is distributed, including the type of object detection sensor that detected it, so the importance can be set according to the sensor specifications.

Furthermore, other vehicles may have object detection sensors that detect surrounding objects, or may not have object detection sensors but may acquire surrounding object detection information from roadside units via communication means with the roadside units and distribute the roadside unit's location information along with the surrounding object detection information. This allows the other vehicle to be considered a vehicle that can provide more information and be assigned a higher importance. In other words, if the other vehicle can acquire at least some of the surrounding object detection information from the roadside unit via communication means installed in the other vehicle, the importance of the other vehicle is determined to be higher.

Although the present disclosure describes exemplary embodiments, the various features, aspects, and functions described in the embodiments are not limited to application to a particular embodiment, but may be applied to the embodiments alone or in various combinations.
Therefore, countless variations not illustrated are contemplated within the scope of the technology disclosed in this specification, including, for example, the modification, addition, or omission of at least one component.

1: In-vehicle communication device, 2: Object detection sensor, 5: Roadside unit, 10: Communication unit, 20: Other vehicle information receiving unit, 30: Importance determination unit, 40: Application unit, 50: Display unit, 101: Processor, 102: Memory, 103: Auxiliary storage device, 104: Transmitter, 105: Receiving device, OV: Host vehicle, VE: Other vehicle, SN: Detection range.

Claims (5)

An in-vehicle communication device comprising: an other vehicle information receiving unit that receives, via vehicle-to-vehicle communication, from another vehicle, vehicle states including the position of the other vehicle and peripheral object detection information that detects objects around the other vehicle, as other vehicle information; and an importance determining unit that determines the importance of the other vehicle based on the received peripheral object detection information. the peripheral object detection information includes position information of the detected object,
The in-vehicle communication device according to claim 1 , wherein the importance determining unit determines the importance of the other vehicle based on the position of the object and the position of the vehicle. the peripheral object detection information includes a type of object detection sensor mounted on the other vehicle;
The in-vehicle communication device according to claim 1 , wherein the importance determining unit determines the importance of the other vehicle based on a type of the object detection sensor that detected the object. The importance determination unit
The in-vehicle communication device according to claim 1 , wherein the importance of the other vehicle is determined to be higher when at least a part of the surrounding object detection information can be acquired from a roadside device by a communication means mounted on the other vehicle. 3. The in-vehicle communication device according to claim 1, further comprising an application unit that executes a driving assistance application using the vehicle state and the peripheral object detection information from the other vehicle in accordance with the importance determined by the importance determination unit.