In-vehicle communication device

Abstract

An in-vehicle communication device (1) is provided with: an other-vehicle information reception unit (20) that receives, from another vehicle (VE), vehicle status including the position of the other vehicle (VE), and surrounding object detection information obtained by detecting objects around the other vehicle (VE), as other-vehicle information via vehicle-to-vehicle communication; and an importance level determination unit (30) that determines the importance level of the other vehicle (VE) on the basis of the received surrounding object detection information.

Description

In-vehicle communication device

[0001] The present disclosure relates to an in-vehicle communication device.

[0002] In recent years, technologies related to vehicle-to-vehicle communication and road-to-vehicle communication have been developed for the purpose of preventing traffic accidents, easing congestion, etc. In vehicle-to-vehicle communication, each vehicle broadcasts its own vehicle information to those around it, thereby supporting the safety of other vehicles. There is also technology that broadcasts information about surrounding objects detected by sensors mounted on vehicles to those around it as V2X (Vehicle to X) messages, which allows vehicles that receive these messages to recognize the presence of surrounding vehicles that they themselves have not been able to detect.

[0003] In vehicle-to-vehicle communications, when there are many vehicles nearby, 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 a warning application that supports collision avoidance, it is not necessary to receive messages from vehicles with a low probability of collision.

[0004] A known technology for reducing the processing load of received messages is to determine the importance of a received message, determine whether verification is necessary based on the importance, and 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, a packet type flag added to the message, the frequency of reception from the same sender, the received power, etc. Furthermore, messages that are determined not to require verification are not verified, thereby reducing the processing load.

[0005] JP 2012-100024 A

[0006] Not all vehicles are equipped with an on-board device capable of V2X communication (hereinafter referred to as a V2X on-board device). Therefore, for vehicles without a V2X on-board device, information transmitted from vehicles equipped with a sensor capable of recognizing surrounding objects is important. Patent Document 1 determines the importance based on the location or proximity of the source vehicle. However, even if the source vehicle is located far away and detects a vehicle without a V2X on-board device that is close to the host vehicle, the message from the source vehicle may be determined to be of low importance. However, information from vehicles without a V2X on-board device that are close to the host vehicle is important to the host vehicle. Thus, there is a possibility that a message from a vehicle that should have been received may be overlooked.

[0007] The present disclosure discloses a technology for solving 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.

[0008] The in-vehicle communication device of the present disclosure includes an other vehicle information receiving unit that receives, via vehicle-to-vehicle communication, other vehicle information from another vehicle, 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 that determines the importance of the other vehicle based on the received surrounding object detection information.

[0009] According to the present disclosure, it is possible to provide an in-vehicle communication device that can appropriately set the importance of messages transmitted from other vehicles and prevent messages that are important to the vehicle from being overlooked.

[0010] 1 is a diagram showing a configuration of an inter-vehicle communication system according to embodiment 1. FIG. 2 is a functional block diagram showing a configuration of an in-vehicle communication device according to embodiment 1. FIG. 3 is a diagram showing an example of a hardware configuration of an in-vehicle communication device according to embodiment 1. FIG. 4 is a diagram for explaining an example of sensors mounted on a vehicle. FIG. 5 is a flowchart for explaining the operation of an in-vehicle communication device according to embodiment 1. FIG. 6 is a flowchart for explaining a procedure for determining importance according to embodiment 1.

[0011] Hereinafter, an embodiment of an in-vehicle communication device according to the present disclosure will be described with reference to the drawings. Note that in each drawing, the same reference numerals indicate the same or corresponding parts. Therefore, detailed descriptions thereof may be omitted to avoid duplication.

[0012] Embodiment 1. An on-vehicle communication device according to embodiment 1 will be described below with reference to the drawings. FIG. 1 is a diagram showing the configuration of an inter-vehicle communication system in which communication is performed between vehicles equipped with an on-vehicle communication device 1 according to embodiment 1. In FIG. 1, a host vehicle OV is equipped with an 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. Note that the other vehicle VE2 in FIG. 1 is equipped with an object detection sensor 2 that detects objects around the vehicle, as described below. As described below, the other vehicles VE can also acquire peripheral object information detected by the roadside unit 5 from the roadside unit 5.

[0013] <Configuration of In-Vehicle Communication Device 1> Next, a description will be given of the configuration of the in-vehicle communication device 1. The in-vehicle communication device 1 has functions of transmitting a message including vehicle information of the host vehicle OV to other surrounding vehicles VE via wireless communication, receiving a message including information regarding 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 message.

[0014] 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 of other vehicles VE around the host vehicle from messages received by the communication unit 10, an importance determining unit 30 that determines the importance of the transmitting 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.

[0015] 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 a communication means compliant with 4G or 5G (5th Generation; fifth generation mobile communication system). Note that, within the vehicle, the connection is made using, for example, CAN (Control Area Network: registered trademark) or the like.

[0016] The other vehicle information receiving unit 20 outputs a message including the vehicle status of the other vehicle VE received by the communication unit 10 to the importance determining unit 30, and determines whether to process the received message depending on the importance set for the source vehicle VE. If it determines to process the message, it decodes the message and acquires vehicle information such as the position, speed, and direction of the other vehicle VE around the subject vehicle. The acquired vehicle information of the other vehicle VE is output to the application unit 40. Note that the message also includes information such as surrounding object detection information detected by sensors mounted on each vehicle. Therefore, the other vehicle information receiving unit 20 also acquires this object detection information.

[0017] 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 importance determination will be described later. The determined importance is output to the other vehicle information receiving unit 20.

[0018] The application unit 40 executes driving assistance applications related to the traveling of the host vehicle OV based on information from the other vehicle 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 the other vehicle VE acquired by the other vehicle information receiving unit 20.

[0019] 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 displays on the road other vehicles VE that may come into contact with the host vehicle OV in the future, or notifies the driver of approaching pedestrians by audio. Note that 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.

[0020] 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 storage device, and an auxiliary storage device 103. The processor 101 is configured by, for example, a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), etc.

[0021] The memory 102 is configured as a volatile storage device such as a random access memory, and the auxiliary storage device 103 is configured as a non-volatile storage device such as a flash memory or a hard disk. A predetermined program executed by the processor 101 is stored in the auxiliary storage device 103, and the processor 101 reads and executes the program as appropriate to perform various arithmetic processing. At this time, the predetermined program is temporarily stored from the auxiliary storage device 103 to the memory 102, and the processor 101 reads the program from the memory 102. The arithmetic processing of each functional unit of the in-vehicle communication device 1 according to the first embodiment is realized by the processor 101 executing the predetermined program as described above. The results of the arithmetic processing by the processor 101 are temporarily stored in the memory 102 and then stored in the auxiliary storage device 103 according to the purpose of the executed arithmetic processing.

[0022] Furthermore, the vehicle VE is provided with a transmitting device 104 and a receiving device 105 as communication modules for communicating with other vehicles VE.

[0023] Next, an example of a vehicle equipped with object detection sensors for detecting objects around the vehicle will be described. FIG. 4 shows an example in which a plurality of object detection sensors are combined and arranged on a vehicle, for example, the example of the other vehicle VE2 in FIG. 1 , and illustrates the detection ranges SN of each object detection sensor 2. In FIG. 4, seven object detection sensors 2, 2a to 2g, are mounted, with three object detection sensors 2a, 2b, and 2g arranged in the front, two object detection sensors 2c and 2f arranged on the sides, and two object detection sensors 2d and 2e arranged in the rear. The detection ranges of each object detection sensor 2 are indicated by fan-shaped dashed lines, and objects can be detected in 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 cover the entire periphery of the vehicle.

[0024] The object detection sensor 2 detects object information around the vehicle. The objects around the vehicle are, for example, traffic participants such as other vehicles, pedestrians, bicycles, and motorcycles that are present around the host vehicle. The object detection sensor 2 is, for example, a camera, radar, LiDAR (Light Detection and Ranging), sonar sensor, etc. that are provided on the host vehicle. The object detection sensor 2 may output surrounding object detection information that links the objects present around the host vehicle with the type of traffic participant categorized as other vehicles, pedestrians, bicycles, motorcycles, etc.

[0025] The camera is installed in a position where it can capture images of the front, sides, and rear of the vehicle, and from the captured images, it obtains information about the environment in which the vehicle is located, such as information about the lane and obstacles in front of the vehicle.

[0026] The radar emits radar light ahead of the vehicle and detects the reflected waves to measure the relative distance and relative speed of an obstacle present ahead of the vehicle, and outputs the measurement results.

[0027] LiDAR detects the position of an object by shining a laser around the vehicle and detecting the time difference between the time it takes for the laser to reflect off an object and return.

[0028] A sonar sensor detects the position and distance of an object by emitting ultrasonic waves to the area around the vehicle and detecting the time difference between the time it takes for the waves to reflect off an object and return.

[0029] 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 the type of object detection sensor 2 used for detection, in a message.

[0030] The roadside device 5 equipped with the object detection sensor 2 distributes a message containing surrounding object detection information including the position information of objects such as vehicles and pedestrians around the roadside device 5 detected by the object detection sensor 2.

[0031] It should be noted that not all other vehicles around the host vehicle need 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 at least one other vehicle VE equipped with an object detection sensor 2 along with an in-vehicle communication device 1 is present within the area where vehicle-to-vehicle communication is performed. If the in-vehicle communication device 1 is equipped with the 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 host vehicle to be equipped with communication means for acquiring peripheral object detection information from the roadside device 5, but if peripheral information can be acquired from the roadside device 5, peripheral object detection information around the vehicle will be added. The importance determination unit 30 determines the importance of each vehicle, taking into account this peripheral object detection information.

[0032] <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. 5. 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. Note that this operation is repeatedly executed at the timing when the communication unit 10 receives a message transmitted from another vehicle VE.

[0033] 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. The importance level can be divided into three levels, such as "high," "medium," and "low." If no importance level is set, it is determined that the message should 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 accumulated in the message receiving buffer of the other vehicle information receiving unit. Criteria can be determined in advance, such as processing only messages from "high" vehicles when the amount of accumulated messages is 80% or more of the maximum buffer capacity. Furthermore, for other vehicles whose messages have not been processed for a certain period of time due to low importance, it is also possible to process messages regardless of the level of importance.

[0034] If it is determined in step S102 that message processing is to be performed (Yes in step S102), the process proceeds to step S103. In step S103, the other vehicle information receiving unit 20 extracts information required 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.

[0035] In step S104, the importance determination unit 30 performs importance determination for the messages for which it has been determined in step S102 that processing should be performed, in order to set the importance of each of the other vehicles VE that are the senders.

[0036] <Importance Determination> Next, the procedure for determining the importance in step S104 of Fig. 5 will be described with reference to the flowchart of Fig. 6. The importance determination unit 30 determines the importance of a message received from another vehicle VE based on the content of the message, 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.

[0037] First, in step S1041, the importance determination unit 30 acquires a message received from another vehicle VE from the other vehicle information receiving unit 20. In step S1042, it is determined whether the received message includes surrounding object detection information.

[0038] If the received message does not include peripheral object detection information (No in step S1042), that is, if the message does not include information about other vehicles other than the vehicle information about the other vehicle VE that sent it, the process proceeds to step S1043. In step S1043, the importance determination unit 30 determines the importance based on the positional relationship between the host vehicle OV and the other vehicle VE. For example, if the distance between the host vehicle OV and the other vehicle VE is short, the other vehicle VE itself may come into contact with the host 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 host 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.

[0039] In step S1042, if the received message includes peripheral 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 Fig. 4 and the message includes peripheral object detection information acquired by the other vehicle VE and transmitted by including the information in the message, the process proceeds to step S1044. In step S1044, the importance determination unit 30 analyzes the peripheral object detection information included in the message, and determines, as a result of the analysis, whether or not a detected object exists in the target area in which the host vehicle OV is traveling.

[0040] If it is determined in step S1044 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, where the importance of the other vehicle VE that is the sender is determined to be “medium.” If it is determined in step S1044 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 is the sender is determined to be “high.”

[0041] Here, an example of determining the importance level using the surrounding object detection information from the other vehicle VE will be described. First, if the transmitting vehicle VE is a vehicle equipped with the object detection sensor 2 described in Fig. 4 and transmits a message including the surrounding object detection information acquired by the other vehicle VE, the importance level of the transmitting vehicle VE is assigned to "medium" or higher.

[0042] (1) When the host vehicle OV executes the function of an alarm application related to an intersection collision or left turn assistance, it is very useful to know that a vehicle detected by the object detection sensor 2 mounted on the other 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 peripheral object detection information by the other 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."

[0043] (2) When the host vehicle OV executes the function of an alarm application for protecting vulnerable road users, it is very useful to know that an object (pedestrian, bicycle) detected by the object detection sensor 2 mounted on the other 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 peripheral object detection information from the other 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."

[0044] (3) In a 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 that is the sender of the information is determined to be “high.” Although the above three examples have been shown, the importance determination is performed in step S1044 depending on whether or not the target area in which the host vehicle OV is traveling includes peripheral object detection information detected by the object detection sensor 2 mounted on the other vehicle VE.

[0045] Furthermore, the importance may be determined according to the specifications of the object detection sensor 2 installed in the other vehicle VE. As described above, there are multiple types of object detection sensors 2, and the situation will vary depending on whether one object detection sensor 2 is installed, multiple object detection sensors 2 are installed, or multiple types of object detection sensors 2 are installed. For example, the importance of a vehicle that can obtain more accurate information based on the detection range, detection accuracy, and number of types of detectable objects of the object detection sensor 2 may be determined to be higher.

[0046] When the host vehicle OV executes the function of an alarm application related to an intersection collision or left turn assistance, 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 having 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.

[0047] Furthermore, the importance may be determined to be high when another vehicle VE acquires surrounding object detection information from the roadside unit 5 and distributes the information by including it in a message. In this case, the importance may be set taking into consideration installation location information of the roadside unit 5. The target for determining the importance is not limited to a vehicle, but may also be a roadside unit.

[0048] 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.

[0049] In addition, since the surrounding object detection information from other vehicles includes object position information, it becomes 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 the impact on the vehicle itself, thereby improving the accuracy of importance determination.

[0050] In addition, other vehicles are equipped with object detection sensors that detect surrounding objects, and the information on detected surrounding objects is distributed along with the type of object detection sensor that detected it, so the importance can be set according to the sensor specifications.

[0051] Furthermore, other vehicles can be set to a higher importance as vehicles that can provide more information by acquiring surrounding object detection information from roadside units using object detection sensors that detect surrounding objects, or by distributing the roadside unit's location information together with the surrounding object detection information even if the other vehicles do not have object detection sensors. In other words, if the other vehicles can acquire at least a portion of the surrounding object detection information from the roadside units using communication means installed in the other vehicles, the importance of the other vehicles is determined to be higher.

[0052] Although exemplary embodiments are described in the present disclosure, the various features, aspects, and functions described in the embodiments are not limited to the application of a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless variations not illustrated are anticipated within the scope of the technology disclosed in this specification. For example, variations in, addition to, or omission of at least one component are included.

[0053] 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: Transmitting device, 105: Receiving device, OV: Host vehicle, VE: Other vehicle, SN: Detection range.

Claims

1. An in-vehicle communication device comprising: an other vehicle information receiving unit that receives from another vehicle via vehicle-to-vehicle communication, as other vehicle information, vehicle conditions including the position of the other vehicle and surrounding object detection information that detects objects around the other vehicle; and an importance determination unit that determines the importance of the other vehicle based on the received surrounding object detection information.

2. The in-vehicle communication device described in claim 1, wherein the surrounding object detection information includes position information of the detected object, and the importance determination unit determines the importance of the other vehicle based on the position of the object and the position of the host vehicle.

3. The in-vehicle communication device of claim 1 or 2, wherein the surrounding object detection information includes the type of object detection sensor mounted on the other vehicle, and the importance determination unit determines the importance of the other vehicle based on the type of the object detection sensor that detected the object.

4. An in-vehicle communication device as described in any one of claims 1 to 3, wherein the importance determination unit determines the importance of the other vehicle to be higher when at least a portion of the surrounding object detection information can be obtained from a roadside unit via communication means installed in the other vehicle.

5. An in-vehicle communication device as described in any one of claims 1 to 4, further comprising an application unit that executes a driving assistance application using the vehicle state and the surrounding object detection information from the other vehicle in accordance with the importance determined by the importance determination unit.

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