Patent Description:
The current broadcast operation method of a road side unit (RSU) is limited by bandwidth. If there are too many object messages, the distance between the object and the intersection can only be used as a basis for selection of messages. In addition, if all object messages are sent by broadcast, RSU cannot accurately provide dangerous object messages, because some object messages (such as vehicles stopped on the roadside, vehicles far away from intersection) are not related to those objects with on-board unit (OBU), and it will result in a waste of resources of wireless transmission bandwidth.

The <CIT> discloses an intersection infrastructure warning system. It includes an edge computing device having a graphics processing unit, one or more sensors that acquire spatial-temporal data of road users, and one or more warning devices that output a warning to warn targeted vulnerable road users of danger. The graphics processing unit uses one or more artificial intelligence algorithms to process the spatial-temporal data of the road users to predict a path, trajectory, behavior, and intent for the road users. The graphics processing unit then analyzes the predictions of the road users to determine convergences between the predictions to determine threat interactions and identify targeted vulnerable road users. In response to determining threat interactions and identifying the targeted vulnerable road users, the edge computing device outputs targeting instructions and warning response instructions to the one or more warning devices to deploy the one or more warning devices to warn the targeted vulnerable road users.

<CIT> discloses an automotive advanced driver assistance system for host motor-vehicle (HMV), has driver of HMV of relevant motor-vehicles (RMV) deemed to be relevant informed to safety of HMV along possible driving path of HMV from its current position.

<CIT> discloses a device for sending and receiving vehicle-to-vehicle safety messages in smart phone, has transceiver for wirelessly broadcasting and receiving messages, where transmissions of priority class do not occur outside time window.

The disclosure is directed to a message transmission system and a method thereof for a roadside equipment, which can send out dangerous object messages based on a degree of danger of the object within the available transmission bandwidth, so as to reduce the transmission volume of vehicle-to-road communication.

The problem of the present invention is solved by a message transmission method for a roadside equipment according to the independent claim <NUM> as well as by a message transmission system according to the independent claim <NUM>. The dependent claims refer to further advantageous developments of the present invention.

The above and other aspects of the disclosure will become better understood with regard to the following detailed description of the embodiment(s). The following description is made with reference to the accompanying drawings.

Please refer to <FIG> and <FIG>. <FIG> is a schematic diagram of the operation of components of a message transmission system <NUM> for a roadside equipment according to an embodiment of the present disclosure, and <FIG> is a schematic diagram of a message transmission method for a roadside equipment according to an embodiment of the present disclosure.

In this embodiment, the message transmission system <NUM> for a roadside equipment includes a dynamic detection device <NUM> for object at the intersection, a sign receiving device <NUM>, a dangerous object classification module <NUM>, and a vehicle-to-road communication device <NUM>. The dynamic detection device <NUM> at the intersection is installed on a side of the road to detect cars, motorcycles, bicycles, or pedestrians (hereinafter referred to as the object <NUM>) passing through the intersection. The dynamic detection device <NUM> at the intersection can include LiDAR modules, laser ranging modules, camera modules, image recognition modules, and computing modules, etc., which can calculate the position, the speed, and the object moving direction of each detected object passing through the intersection in real time, the relative distance between the detected object and the intersection, and the relative distance between the object and the object.

In this embodiment, the dynamic detection device <NUM> at the intersection can cooperate one or more LiDAR modules, laser ranging modules or camera modules to obtain the external sensor information <NUM> corresponding to the object at the intersection, and obtain different types of external sensor information <NUM> through sensor fusion <NUM>, which are aggregated into a cluster of object data <NUM> at the intersection for the machine to determine. The fused external sensor information <NUM> includes the position, the speed, the acceleration, the object moving direction and relative distance of the objects, etc. In addition, the fused external sensor information <NUM> can also include the type of objects (for example, truck, passenger car, bus, motorcycle), the state of the object (stationary, moving, straight moving, turning, decelerating, accelerating, etc.), determine whether the relative distance between the object and the intersection is greater than or less than a preset threshold, and whether the relative distance between the object and the object is greater than or less than a preset threshold, etc..

Please refer to <FIG>. Generally, the intersection <NUM> of a road can be an area surrounded by three or four road sections L1-L4, that is, the middle rectangular area defined by three or four road sections L1-L4 is the intersection <NUM>, but the road sections are not limited to four, and it may be more than four sections. Each of the road sections L1-L4 is provided with a traffic sign <NUM> (traffic light or pass/turn indicator) to control the vehicles passing through the intersection <NUM>, the pass direction of vehicles, and the pass time of vehicles. In addition, each intersection <NUM> has a traffic signal controller (not shown in the figure. Through the network communication of the traffic signal controller, the traffic signal of each road section L1-L4 can be controlled in series, and the signs of each road section will not conflict to ensure the safety of vehicles passing through the intersection <NUM>.

In this embodiment, the signal receiving device <NUM> may be connected to or wirelessly communicate with the traffic signal controller (not shown in the figure) of the intersection <NUM> to receive a sign phase information <NUM> at the intersection and a road map information <NUM>. The sign phase information <NUM> includes signals, for example, red, yellow, green, left-turn green, right-turn green, and other signals. Road map information <NUM> includes, for example, the location of the intersection (e.g. the GPS coordinates of the center of the intersection), the type of intersection, the intersection area, the location of the sign, the position of the crossing lines, and the position of the threshold <NUM> of each road section, etc..

In this embodiment, the dynamic detection device <NUM> and the sign receiving device <NUM> can simultaneously input the external sensor information <NUM>, the road map information <NUM>, and the intersection sign phase information <NUM> corresponding to the intersection <NUM> for the message transmission system <NUM> to determine the objects near the intersection <NUM> in real time, the road map information <NUM>, and the intersection sign phase information <NUM> etc., as shown in <FIG>.

Please refer to <FIG> is a schematic diagram of objects <NUM> at the intersection and their positions, speeds, and object moving directions according to an embodiment of the present disclosure. Each road section L1-L4 has two lanes in both directions, namely the lane leading to intersection <NUM> and the lane leaving intersection <NUM>. There are a total of eight lanes. Each lane has a plurality of objects <NUM> (that is, vehicles) driving on the road, each of the positions of the vehicles is detected, and the head of the vehicles is object moving direction. The italicized numbers next to the vehicles indicate the speed of each object. The speed will be adjusted dynamically according to the state of the vehicle. The speed of some vehicles that have left the intersection <NUM> is not displayed. The following is only an example showing the speed of vehicles approaching the intersection <NUM> as a basis for classification. In this embodiment, the dangerous object classification module <NUM> can analyze the position, the speed, the object moving direction, and the signs in object moving direction of each detected object passing through the intersection <NUM> to output the classification of dangerous objects of different groups.

Please refer to <FIG>, <FIG>, and <FIG>. <FIG> is a schematic diagram of a message transmission method for a roadside equipment according to an embodiment of the present disclosure. The message transmission method includes the following steps S110 to S140. In step S110, a plurality of external sensor information <NUM> is received. In step S120, an intersection sign phase information <NUM> and a road map information <NUM> are entered. In step S130, an object position analysis <NUM>, a speed analysis <NUM>, and a sign analysis <NUM> in object moving direction are performed based on the external sensor information <NUM>, the intersection sign phase message <NUM>, and the road map information <NUM>, and the classification of dangerous objects of different groups <NUM> is outputted. In step S140, a dangerous object message <NUM> with a higher dangerous object classification is preferentially selected and transmitted within an available transmission bandwidth. In such way, the present disclosure can send a dangerous object message <NUM> based on the degree of danger of the objects within the available transmission bandwidth, so as to reduce the transmission volume of vehicle-to-road communication.

A specific example of the classification of dangerous objects <NUM> has been shown in <FIG>. <FIG> is a schematic diagram of the object position analysis <NUM> at the intersection according to an embodiment of the present disclosure; <FIG> is a schematic diagram of objects at the intersection and the classification of dangerous objects in group D after the position analysis <NUM> of <FIG>; <FIG> is a schematic diagram of the sign analysis <NUM> in object moving direction and speed analysis <NUM> of the objects at the intersection according to an embodiment of the present disclosure; <FIG> is a schematic diagram of the classification of dangerous objects at the intersection in groups C and D after the sign analysis <NUM> and speed analysis <NUM> of <FIG>; <FIG> is a schematic diagram of the analysis <NUM> of the degree of danger of the objects at the intersection according to an embodiment of the present disclosure; <FIG> is a schematic diagram of the classification of dangerous objects at the intersection in groups A, B, C, and D after the analysis <NUM> of the degree of danger of <FIG>.

First, in <FIG>, the object position analysis <NUM> includes (a) determining whether the object <NUM> is on the road, and if so, continues (b) determining whether the object <NUM> is close to the intersection. If it is determined that the object <NUM> is not on the road, for example, the vehicles D1 and D2 parked on the side of the road are not dangerous to other driving vehicles, so this type of object <NUM> is classified into a dangerous object of group D. In addition, if it is determined that the object <NUM> is far away from the intersection, for example, vehicles D3 to D6, it means that the vehicle has passed the intersection or far enough away from the intersection, and is not dangerous for other driving vehicles, so this type of object <NUM> is classified into a dangerous object of group D. In addition, if it is determined that the object <NUM> is on the road and is close to the intersection <NUM>, for example, the vehicle C1, the sign analysis <NUM> in the object moving direction and the speed analysis <NUM> are performed to determine whether this type of object <NUM> is classified into a dangerous object of group C. It is understandable that the danger degree of the dangerous object of group C is higher than that of the dangerous object of group D.

Further, in <FIG> and <FIG>, the sign analysis <NUM> and speed analysis <NUM> of the object at the intersection include (a) determining whether the sign in object moving direction is a green light, if not, continue (b) determining whether the speed of the object is greater than a threshold. When the sign in object moving direction is a green light, the object <NUM> can be classified into a dangerous object of group C; when the sign in object moving direction is not green light and the speed of the object is less than the threshold, the object <NUM> can be classified into a dangerous object of group C; when the sign in object moving direction is not green light and the speed of the object is greater than the threshold, continue to perform the analysis <NUM> of degree of danger of the object to determine whether the object <NUM> is classified into a dangerous object of group B.

For example, in <FIG>, when the north-south lane is green light and the east-west lane is red light, the vehicles on the north-south lane are classified into dangerous objects of group C except for the classification of dangerous objects of group D. Then, when the speed of the vehicle in the east-west lane is less than the threshold (for example, <NUM>/hr), for example, vehicles C2 and C3, it is not dangerous for the vehicles in the north-south lane, so this type of object <NUM> is classified into a dangerous object of group C. When the speed of the vehicle in the east-west lane is greater than a threshold, for example, vehicle B1, it may be dangerous to the vehicle in the north-south lane. An analysis <NUM> of the degree of danger of the object is performed to determine whether this type of object <NUM> is classified into a dangerous object of group B. It is understandable that the danger degree of the dangerous object of group B is higher than that of the dangerous object of group C.

Further, in addition to the above-mentioned object position analysis <NUM>, speed analysis <NUM>, and sign analysis <NUM> in object moving direction, the system <NUM> can perform an analysis <NUM> of the degree of danger based on the external sensor information <NUM>, intersection sign phase information <NUM>, and road map information <NUM>. In <FIG> and <FIG>, the analysis <NUM> of the degree of danger of the object at the intersection includes (a) determining whether the time from the object <NUM> to the intersection stop line <NUM> is greater than a threshold, if not, continues (b) determining whether the object <NUM> exceeds the stop line <NUM>. When the time from the object <NUM> to the stop line <NUM> of the intersection is greater than the threshold, the object <NUM> can be classified into a dangerous object of group B; when the time from the object <NUM> to the stop line <NUM> of the intersection is less than the threshold and the object <NUM> does not exceed the stop line <NUM>, the object <NUM> can be classified into a dangerous object of group B; when the time from the object <NUM> to the stop line <NUM> of the intersection is less than the threshold and the object <NUM> exceeds the stop line <NUM>, the object <NUM> can be classified into a dangerous object of group A.

For example, in <FIG>, when the east-west lane is red light, and the time from a vehicle on the east-west lane to the stop line <NUM> of the intersection is greater than a threshold, for example, the vehicle B1, it indicates that the vehicle is away from the stop line <NUM> about a certain distance, and it is still possible to stop without exceeding the stop line and is not dangerous for vehicles on the north-south lane. Therefore, this type of object <NUM> can be classified into a dangerous object of group B. When a vehicle in the east-west lane exceeds the stop line <NUM>, for example, the vehicle A1, it may collide with a vehicle in the north-south lane (e.g., the vehicle A2) at a next time, and this type of object <NUM> can be classified into a dangerous objects of group A. In this embodiment, when an object <NUM> with a high degree of danger (e.g., the vehicle A1) appears in the moving direction of the vehicle A2, the classification of the dangerous object of the vehicle A2 is increased to group A so as to have priority to send the dangerous object message <NUM> to the vehicles A1 and A2. It is understandable that the danger degree of the dangerous object of group A is higher than that of the dangerous object of group B, and the danger degree of the dangerous object of group B is higher than that of the dangerous object of group C.

In this embodiment, the vehicle-to-road communication device <NUM> preferentially selects and transmits a dangerous object message <NUM> with a higher dangerous object classification. In other words, the message of the dangerous object classification of group A is first transmitted, and then the message of the dangerous object classification of group B is transmitted, and then the messages of the dangerous object classification of group C and group D is finally transmitted. According to the limitation of the current transmission bandwidth and the classification of the degree of danger from high to low, the vehicle-to-road communication device <NUM> sends a message to notify the object <NUM> at the intersection to ensure that the system <NUM> can instantly send a dangerous object message <NUM> within the available transmission bandwidth, reduce a chance of collision of objects <NUM> at the intersection and reduce the transmission volume of vehicle-to-road communication.

The system <NUM> can scan the message of the surrounding vehicles at the intersection through radar and send the message through the roadside equipment with the function of dedicated short range communication (DSRC). The object messages at the intersection can be stored in the basic safety message (SAE J2735 BSM) and is broadcast regularly through exclusive short-range wireless communication. When the on-board unit (OBU) of auto-driving car receives this message and parses it, the safety collision avoidance system judges the message with its own information by algorithm to determine whether a collision will occur to make an action to stop the vehicle automatically.

For example, the internet of vehicles (V2X) technology is used on a road to improve the safety of auto-driving cars, and the primary task is how to make vehicles have safety protection during driving and reduce the incidence of traffic accidents. The disclosure can be used in the vehicle-to-vehicle transmission, vehicle-to-road transmission and intersection sign transmission to strengthen driving safety, avoid collisions at intersection, and give priority to warn the drivers whose vehicles are about to collide (for example, vehicles A1 and A2) to pay attention to driving safety. Therefore, when a vehicle equipped with on-board unit (OBU) approaches the roadside equipment and is about to pass through the intersection <NUM>, the OBU can receive the road map information <NUM>, sign phase information <NUM> at the intersection and the classification <NUM> of dangerous objects of the other vehicles from the system <NUM>, but it is not limited, the driver can see whether there is a dangerous object message <NUM> (such as a sound or a picture) according to the in-vehicle user interface to help the driver brake early or reduce the speed of the car. In addition, the disclosure can also be used in a left-turn anti-collision system to notify the driver of the dangerous object message <NUM> as soon as possible to prevent the driver's vision from being blocked by the oncoming vehicle waiting to turn left when the vehicle is turning left and causing a danger of collision with a straight-moving vehicle.

Claim 1:
A message transmission method for a roadside equipment, wherein the message transmission method comprises:
(S110) receiving information from a plurality of external sensors (<NUM>);
(S120) receiving a road intersection sign phase information (<NUM>) and a road map information (<NUM>);
(S130) performing an object position analysis (<NUM>), a speed analysis (<NUM>), and a sign analysis in object moving direction (<NUM>) based on the external sensor information (<NUM>), the road intersection sign phase information (<NUM>), and the road map information (<NUM>);
outputting a classification (<NUM>) of dangerous objects in different groups according to the object position analysis (<NUM>), the speed analysis (<NUM>), and the sign analysis in object moving direction (<NUM>); and
(S140) according to a current transmission bandwidth limitation and the classification of the dangerous objects, a dangerous object message (<NUM>) with a higher classification of the dangerous objects is preferentially selected and transmitted by a vehicle-to-road communication device (<NUM>) within an available transmission bandwidth;
wherein the classification (<NUM>) of dangerous objects in different groups comprises determining following steps:
i) when the object (<NUM>) is on a road (L1 to L4) and the object (<NUM>) is far away from the intersection (<NUM>), the object (<NUM>) is classified into a dangerous object of group D;
ii) when a sign (<NUM>) in the object moving direction is not a green light and a speed of the object (<NUM>) is less than a threshold, the object (<NUM>) is classified into a dangerous object of group C;
iii) when a time from the object (<NUM>) to a stop line (<NUM>) is less than a threshold and the object (<NUM>) does not exceed the stop line (<NUM>), the object (<NUM>) is classified into a dangerous object of group B;
iv) when the time from the object (<NUM>) to the stop line (<NUM>) is less than the threshold and the object (<NUM>) exceeds the stop line, (<NUM>) the object (<NUM>) is classified into a dangerous object of group A;
wherein the danger degree of the dangerous object of group A is higher than that of the dangerous object of group B, the danger degree of the dangerous object of group B is higher than that of the dangerous object of group C and the danger degree of the dangerous object of group C is higher than that of the dangerous object of group D.