KR102543820B1 - Vehicle slip prevention system with ai v2x obu - Google Patents

Abstract

The present invention relates to a slip accident prevention system using an AI V2X OBU, and more particularly, by detecting that a vehicle is slipping to generate slip occurrence information, and generating the slip occurrence information through a V2X OBU mounted on a vehicle to another V2X It is about a slip accident prevention system using AI V2X OBU that can prevent slip accidents such as collisions by transmitting to a vehicle equipped with OBU. The slip accident prevention system using the AI V2X OBU according to the present invention detects a V2X (vehicle to everything) RSU (Roadside Unit) installed on the roadside and wheel spin or slip condition of the road surface. It includes a vehicle equipped with a V2X OBU (On Board Unit) that transmits and receives a slip state detection unit and a safety message (Basic Safety Message (BSM)) in a V2X manner.

Description

Slip accident prevention system using AI V2X OBU {VEHICLE SLIP PREVENTION SYSTEM WITH AI V2X OBU}

The present invention relates to a slip accident prevention system using an AI V2X OBU, and more particularly, by detecting that a vehicle is slipping to generate slip occurrence information, and generating the slip occurrence information through a V2X OBU mounted on a vehicle to another V2X It is about a slip accident prevention system using AI V2X OBU that can prevent slip accidents such as collisions by transmitting to a vehicle equipped with OBU.

The condition of the road surface is the most important factor that determines the driving safety of a vehicle, and a slippery road surface occurs due to snowfall in winter or heavy rain in summer. When a vehicle drives on such a slippery road surface, a wheelspin phenomenon occurs during acceleration and a skid phenomenon occurs during deceleration.

In general, a driver can easily recognize a large slippage of a vehicle, but it is difficult for a driver to easily recognize a slight wheeling phenomenon during acceleration or a slight slippage during deceleration on a light black ice road surface. Therefore, if such a slight wheel phenomenon or slipping phenomenon can be detected and immediately provided to the driver, traffic accidents can be prevented by inducing the driver to decelerate.

As a method of detecting the slipping phenomenon of a vehicle on a road surface, a method of using a difference between a moving speed of a vehicle and a rotational speed of wheels has been proposed (Patent Registration No. 1308994 (2013. 09. 17.)). This detection method can determine skid on the road surface when wheelspin or skid of the vehicle occurs while the vehicle is driving on a straight line on a flat icy road surface.

However, the method as described above controls only the sliding preceding vehicle, and does not solve the situation in which the following vehicle collides as the preceding vehicle slips. When a preceding vehicle slips on a slippery road surface on a highway or general road, a rear vehicle following the preceding vehicle may collide with the preceding vehicle.

After the collision, a rear vehicle following the target vehicle may not recognize the collision between the target vehicle and the preceding vehicle in advance, and thus an additional collision accident may occur. In other words, a chain collision accident can occur due to the slipping of the preceding vehicle, and when there is a vehicle in front of it, the need for a system capable of preventing a collision accident caused by the vehicle slipping by transmitting information about the vehicle to the vehicle behind it. this is emerging

Republic of Korea Patent Registration No. 10-0721343 (Announced on May 25, 2007) Republic of Korea Patent Registration No. 10-0262587 (published on August 01, 2000)

An object of the present invention to solve the above problems is to generate slip occurrence information when a vehicle slipping phenomenon is detected and transmit the generated slip occurrence information to another vehicle to prevent chain collision accidents using AI V2X OBU. To provide an accident prevention system.

Another object of the present invention is to include skid information and hopping information in a safety message (BSM) when transmitting and receiving skid information through V2X communication, and the safety message can communicate between vehicles according to the included hopping information. It is to provide a slip accident prevention system using V2X OBU.

Another object of the present invention is to include hopping information in the extended information header of the safety message, and the V2X OBU receiving the safety message can process the safety message according to the presence or absence of the extended information header, thereby improving the processing speed of the safety message. It is to provide a slip accident prevention system using AI V2X OBU that can be done.

In order to achieve the above object, a slip accident prevention system using AI V2X OBU according to an embodiment of the present invention is a V2X (vehicle to everything) RSU (Roadside Unit) and wheel spin (wheel spin) installed on the roadside. It includes a vehicle equipped with a slip state detection unit that detects a slip state or a slip state of the road surface and a V2X OBU (On Board Unit) that transmits and receives a safety message (Basic Safety Message (BSM)) in a V2X manner. When the wheelspin or the slipping state of the road surface is detected, the detector generates slip generation information and transmits it to the V2X OBU, and the V2X OBU generates the safety message including the received slip generation information, , characterized in that the safety message is transmitted to the V2X RSU or V2X OBU mounted on another vehicle.

The slip state detection unit includes a GPS sensor for measuring the position and moving speed of the vehicle, a wheel speed sensor for measuring wheel rotation speed of the vehicle, a steering angle sensor for measuring a steering angle of the vehicle, and a yaw angle of the vehicle. A gyro sensor for measuring the gyro sensor, the GPS sensor, the wheel speed sensor, the steering angle sensor, and a slip occurrence determination module for detecting the occurrence of the wheelspin or slip of the road surface based on data measured by the steering angle sensor and the gyro sensor, and the wheelspin or A slip occurrence information generating unit generating slip occurrence information and transmitting the slip occurrence information to the V2X OBU when the slip occurrence of the road surface is detected, wherein the slip occurrence determination module compares the moving speed of the vehicle with the rotational speed of the wheels, Wheelspin is detected, and the steering angle is compared with the yaw angle to detect the sliding state of the road surface.

After receiving the safety message, the V2X OBU mounted on the other vehicle processes the safety message to extract slip occurrence information and transmits it to the human-machine interface (HMI) of the vehicle, and the HMI transmits the safety message The sliding occurrence information included in is expressed, and the sliding occurrence information includes location information where the sliding occurs.

The V2X OBU includes a V2X data transmission device and a V2X data reception device, and the V2X data transmission device generates a packet containing the safety message and hopping information, and transmits the packet and the slip occurrence information to the safety message. A generating unit including a generating unit and a transmitting unit that transmits the safety message to a V2X data receiving device mounted in another vehicle according to the V2X communication standard according to the hopping information, wherein the V2X data receiving device includes the safety message transmitted by the transmitting unit. A receiving unit for receiving the safety message, a processing unit for processing the safety message, and a retransmitting unit for retransmitting the safety message to a V2X data receiving device mounted in another vehicle in accordance with the V2X communication standard according to the hopping information, It is transmitted to the vehicle to prevent a collision accident.

The safety message includes an extension information header included in the packet, the extension information header includes a header in which the hopping information is recorded, and the header includes a first header, a second header, and a third header. wherein the first header includes information on the remaining number of hops deducted according to transmission of the packet and lifetime information in which the remaining time of the packet is stored, and the second header includes information on the maximum number of hoppings of the packet and transmission method information indicating a transmission method of the packet, wherein the third header includes identification information of the packet, initial source information indicating information of a device that generated the packet, and final destination information of the packet; , When processing the safety message, the processing unit determines whether the extended information header exists in the safety message, and if the extended information header does not exist in the safety message as a result of determining whether the extended information header exists or not , the safety message is not processed any more, and if the extended information header exists in the safety message as a result of determining whether the extended information header exists, the extended information header is extracted from the safety message and extracted. The packet is extracted from the extended information header, the header is extracted from the extracted packet, the transmission method information is extracted from a second header of the extracted header, and the transmission method information is extracted based on the extracted transmission method information. The transmission method of the packet is determined, and if the transmission method of the packet is the unicast method as a result of the determination of the transmission method, the final destination information is extracted from the third header of the extracted header, and the extracted final destination information Based on determining whether the final destination of the received message is the V2X data receiving device, and as a result of determining whether the final destination is the V2X data receiving device, if the final destination of the received safety message is the V2X data receiving device, the received One safety message is stored in a database, and when the slip occurrence information is transmitted to another vehicle, the processing speed of the safety message is increased to prevent a collision accident.

According to the slip accident prevention system using the AI V2X OBU of the present invention, when a slipping phenomenon of a vehicle is detected, a chain collision accident can be prevented by generating slip occurrence information and transmitting the generated slip occurrence information to another vehicle.

According to the slip accident prevention system using the AI V2X OBU of the present invention, when sending and receiving slip occurrence information through V2X communication, slip occurrence information and hopping information are included in a safety message (BSM), and the safety message is transmitted according to the included hopping information. There is an effect that enables vehicle-to-vehicle communication.

According to the slip accident prevention system using the AI V2X OBU of the present invention, hopping information is included in the extended information header of the safety message, and the V2X OBU receiving the safety message can process the safety message depending on the presence or absence of the extended information header. It is possible to improve the processing speed of safety messages.

1 is a block diagram briefly showing the configuration included in the slip accident prevention system using AI V2X OBU according to the present invention.
2 is a block diagram showing the configuration of a slip state detection unit mounted on a vehicle according to the present invention.
3 is a block diagram showing the configuration of a V2X OBU mounted on a vehicle according to the present invention.

Hereinafter, some embodiments of the present invention will be described in detail through exemplary drawings. In adding reference numerals to components of each drawing, it should be noted that the same components have the same numerals as much as possible, even if they are displayed on different drawings.

And, in describing the embodiments of the present invention, if it is determined that a detailed description of a related known configuration or function hinders understanding of the embodiments of the present invention, the detailed description will be omitted.

Also, terms such as first, second, A, B, (a), and (b) may be used to describe components of an embodiment of the present invention. These terms are only used to distinguish the component from other components, and the nature, order, or order of the corresponding component is not limited by the term.

In this specification, the singular form also includes the plural form unless otherwise specified in the phrase. The terms "comprising" and/or "comprising" used in the specification do not exclude the presence or addition of one or more other components other than the recited components.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

V2X communication means communication between vehicles and everything on the road, such as vehicles and vehicles (V2V), vehicles and pedestrians (V2P), and traffic facilities such as base stations, vehicles, and traffic lights (V2I).

1 is a block diagram briefly showing the configuration included in the slip accident prevention system using AI V2X OBU according to the present invention.

Referring to FIG. 1, the slip accident prevention system using AI V2X OBU according to the present invention is a vehicle equipped with V2X (vehicle to everything) RSU (Roadside Unit) 200 and V2X OBU (On Board Unit) 120 (100).

The V2X RSU 200 according to the present invention is a kind of base station installed on a roadside to communicate with a V2X module installed in the vehicle 100 in a V2X manner, and is also referred to as a roadside base station. The V2X RSU 200 may communicate with the vehicle 100 equipped with the V2X OBU 120 in a V2X manner. V2X includes a WAVE method and a C-V2X method, and the V2X RSU 200 according to the present invention may be a hybrid V2X RSU 200 supporting both the WAVE method and the C-V2X method. Details of the V2X RSU 200 will be described later.

The vehicle 100 according to the present invention is equipped with a V2X OBU 120 that generates a safety message (BSM, Basic Safety Message) and transmits and receives the generated safety message to another vehicle 100 in a V2X manner. The safety message is a message containing basic information of the vehicle 100 related to the location, speed, acceleration, brake operation, etc. of the vehicle 100 in order to provide safety services related to the vehicle 100 .

The vehicle 100 according to the present invention further includes a slip state detection unit 110 that detects wheel spin or a slip state of the road surface.

2 is a block diagram showing the configuration of the slip state detection unit 110 mounted on the vehicle 100 according to the present invention.

Referring to FIG. 2 , the slip state detection unit 110 according to the present invention includes a GPS sensor 111 for measuring the position and moving speed of the vehicle 100 in order to detect wheelspin or a road slip state, the vehicle A wheel speed sensor 113 for measuring the wheel rotational speed of the vehicle 100, a steering angle sensor 115 for measuring the steering angle of the vehicle 100, the yaw angle of the vehicle 100 and the speed at which the yaw angle changes Based on the information measured by the gyro sensor 117 measuring the yaw rate, the GPS sensor 111, the wheel speed sensor 113, the steering angle sensor 115, and the gyro sensor 117, the wheel and a slip occurrence determination module 119 for detecting spin or slip on the road surface.

The GPS sensor 111 according to the present invention measures the vehicle transitional speed of the driving vehicle 100 and provides it to the slip occurrence determination module 119. Since the majority of recent vehicles 100 are car-navigation-equipped vehicles 100 equipped with a GPS module, accurate movement of the vehicle 100 in motion by using the GPS module mounted in the car-navigation as the GPS sensor 111 speed can be measured.

The wheel speed sensor 113 according to the present invention is attached to a wheel of the vehicle 100 to measure the rotational speed of the wheel of the vehicle 100 while driving, and provides the measured data to the slip occurrence determination module 119 . As the wheel speed sensor 113 , those having various structures capable of measuring the wheel rotational speed of the vehicle 100 in motion may be used.

The steering angle sensor 115 according to the present invention measures the steering angle of the driving vehicle 100 and provides the measured data to the slip occurrence determination module 119 . The steering angle sensor 115 may be installed in a steering device of the vehicle 100 and have various structures capable of measuring the steering angle of the vehicle 100 .

The sliding state detection unit 110 according to the present invention may further include a G sensor (not shown). The G sensor is mounted on the vehicle 100 to measure left/right rotational acceleration and thumping acceleration of the vehicle 100 while driving, and provides the measured data to the slip occurrence determination module 119 . The rotational acceleration of the vehicle 100 may be measured by measuring the acceleration in the Y-axis direction of the G sensor. In addition, the vertical motion acceleration of the vehicle 100 can be measured by measuring the acceleration in the Z-axis direction of the G sensor. The G sensor measures the rotational acceleration of the vehicle 100 when the vehicle 100 makes a left turn, right turn, or U-turn, and when the vehicle 100 is driving on a speed bump, anti-slip pavement, or over a pothole, the vehicle 100 One of various structures capable of measuring the up and down acceleration of the can be used.

The gyro sensor 117 according to the present invention is mounted on the vehicle 100 and measures the yaw angle of the driving vehicle 100 and the yaw rate at which the yaw angle changes, and converts the measured data to a slip occurrence determination module. (119). As the gyro sensor 117 , those having various structures capable of measuring the yaw angle of the vehicle 100 may be used.

The slip occurrence determination module 119 according to the present invention collects measurement data from the GPS sensor 111, the wheel speed sensor 113, the steering angle sensor 115, the G sensor, and the gyro sensor 117, Based on these data, it is determined and detected whether wheelspin of the vehicle 100 during driving or slippage of the road surface has occurred. That is, the slip occurrence determination module 119 collects driving characteristic data of the vehicle 100 and uses them as analysis data to determine whether the road surface on which the vehicle 100 is running is in a slippery state.

The slip occurrence determination module 119 according to the present invention collects movement speed data of the vehicle 100 from the GPS sensor 111 and wheel rotation speed data of the vehicle 100 from the wheel speed sensor 113, Steering angle data of the vehicle 100 is collected from the steering angle sensor 115, rotational acceleration data and heaving acceleration data of the vehicle 100 are collected from the G sensor, and yaw angle data of the vehicle 100 is collected from the gyro sensor 117. collect

The slip occurrence determination module 119 according to the present invention compares the moving speed of the vehicle 100 measured and collected from the GPS sensor 111 and the rotational speed of the wheel measured and collected from the wheel speed sensor 113 to determine wheel spin is detected, and the steering angle measured and collected from the steering angle sensor 115 and the yaw angle measured and collected from the gyro sensor 117 are compared to detect the sliding state of the road surface.

The slip occurrence determination module 119 according to the present invention, for example, calculates the difference between the moving speed of the vehicle 100 and the wheel rotation speed, compares the calculated value with a first threshold value, and calculates the rotational acceleration as a second The difference between the yaw angle and the steering angle of the vehicle 100 is calculated, the calculated value is compared with a third threshold value, and the heave acceleration of the vehicle 100 is compared with a fourth threshold value. From these comparison results, the slip occurrence determination module 119 detects wheel spin and the slip state of the road surface. Appropriate values may be selected as preset values for the first to fourth threshold values. For example, as the first threshold value, an appropriate difference value between a moving speed and a wheel rotation speed, which can be a criterion for determining slip of the vehicle 100 traveling in a straight line in a normal state, may be selected. That is, the first threshold is set to a value at which slip of the vehicle 100 hardly occurs on the road surface when the difference between the moving speed of the vehicle 100 and the rotational speed of the wheels is less than or equal to the difference. And, as the second threshold value, an appropriate rotational acceleration value capable of determining the rotation of the vehicle 100, such as a left turn, a right turn, or a U-turn, may be selected. And, as the third threshold value, an appropriate difference value between the yaw angle and the steering angle, which can be a criterion for determining the slip of the vehicle 100 traveling on a curve, may be selected. In addition, as the fourth threshold value, an appropriate vertical motion acceleration value capable of determining when the vehicle 100 is driving on a rough road surface such as a speed bump, anti-skid pavement, or pothole may be selected. The first to fourth threshold values may be set by a user through a threshold value setting unit (not shown). The threshold value setting unit is connected to the slip occurrence determination module 119, and when the user sets the first to fourth threshold values through the threshold value setting unit, the input threshold values are provided to the slip occurrence determination module 119.

The slip occurrence determination module 119 according to the present invention may use the first to fourth threshold values learned using a known AI algorithm when detecting wheel spin or a slip state of the road surface by applying the above-described method. . Therefore, the slip occurrence determination module 119 may determine whether the vehicle 100 or the wheels are slipping by applying an AI algorithm after collecting information through sensors mounted in the vehicle 100 to determine whether or not a slip occurs while driving. .

In this specification, it is described that a GPS sensor 111, a wheel speed sensor 113, a steering angle sensor 115, a G sensor, and a gyro sensor 117 are used to measure the driving characteristics of the vehicle 100. In addition to these, various other sensing devices capable of collecting or measuring driving characteristics of the vehicle 100, such as moving speed, wheel rotational speed, steering angle, rotational acceleration, mutual oscillation acceleration, and yaw angle, may be used, e.g. For example, CAN data of a CAN module mounted in the vehicle 100 may be used. In addition, the slip occurrence determination module 119 may be changed to another configuration that performs a function of determining whether or not the vehicle 100 has slipped by receiving driving characteristic data of the vehicle 100 and performing calculation processing thereon.

The slip state detection unit 110 according to the present invention further includes a slip occurrence information generator (not shown) generating slip occurrence information when the slip occurrence determination module 119 detects wheelspin or a slip state of the road surface. The slip generation information generation unit transmits the generated slip generation information to the V2X OBU 120 mounted in the vehicle 100.

The V2X OBU 120 according to the present invention transmits the received slip generation information. That is, the V2X OBU 120 transmits the slip occurrence information detected by the slip occurrence determination module 119 to the V2X RSU 200 or another vehicle 100, preferably, a V2X OBU mounted on the rear vehicle 100 ( 120).

The V2X OBU 120 according to the present invention generates a safety message and transmits it to the V2X OBU 120 of another vehicle 100. At this time, the V2X OBU 120 includes the received slip occurrence information in the generated safety message It can be transmitted to the V2X OBU 120 of the other vehicle 100.

After receiving the safety message, the V2X OBU 120 of the other vehicle 100 processes the received safety message, extracts the slip occurrence information included in the safety message, and then sends the extracted slip occurrence information to the HMI of the vehicle 100. (130) (human machine interface). Upon receiving the slip occurrence information, the HMI 130 displays the slip occurrence information. The HMI 130 includes a navigation device mounted on the vehicle 100 or a smart phone connected to the vehicle 100 . The slip occurrence information displayed on the HMI 130 includes location information of the vehicle 100 where the slip occurs. Accordingly, the location of the vehicle 100 where the slip occurred and the distance to the location may also be included. In addition to location information, the slip generation information may also include a reason for the slip, that is, icing or blisters on the road surface. The HMI 130 may display a warning sound or a slip warning message when displaying slip occurrence information.

3 is a block diagram showing the configuration of the V2X OBU 120 mounted on the vehicle 100 according to the present invention.

Referring to FIG. 3, the V2X OBU 120 according to the present invention receives V2X data from the V2X data transmission device 121 and the V2X RSU 200 for transmitting V2X data or V2X data of another vehicle 100. It includes a V2X data receiving device 123 for receiving V2X data from the transmitting device 121.

First, the V2X data transmission device 121 according to the present invention generates a packet containing a safety message and hopping information, and a generator that includes the generated packet and the slip generation information received from the slip generation information generator in the safety message ( 1211), and a transmitter 1213 that transmits a safety message including hopping information and slip generation information according to the V2X communication standard to the V2X data receiving device 123 mounted in another vehicle 100 according to the hopping information.

The generation unit 1211 according to the present invention generates a packet containing hopping information. A packet generated by the generation unit 1211 includes a header and a payload. At this time, the header includes an extension information header in which hopping information is recorded. The extended information header includes a first header, a second header, and a third header. The payload includes the remaining data of the packet excluding the header. In general, the address or order to which data is to be delivered is recorded in the header of the packet.

In this specification, hopping may mean a state in which data is transmitted and received between nodes. The V2X OBU 120 according to the present invention, that is, the V2X data transmission device 121 and the reception device 123 are mounted on the vehicle 100 and can transmit and receive data between the vehicles 100. At this time, each vehicle 100 may serve as a router. Accordingly, data received from one vehicle 100 to another vehicle 100 may be transmitted. In this case, data transfer from one vehicle 100 to another vehicle 100 may be referred to as hopping.

In this specification, hopping information may be information required, generated, or modified during hopping. Briefly, information about a source where data is generated, information on a router receiving and retransmitting data in the middle, information on a destination containing information on a final destination, or Information on the number of remaining hopping counts may be included.

The generation unit 1211 according to the present invention generates a packet containing hopping information, and includes the generated packet in a Basic Safety Message (BSM) message or a Radio Technical Commission for Maritime Services (RTCM) message. As described above, the BSM message is called a safety message and is a message containing basic information of the vehicle 100 related to the location, speed, acceleration, brake operation, etc. of the vehicle 100 to provide vehicle safety services. BSM messages are generated in the vehicle 100 and transmitted to other vehicles 100 . Thus, vehicle 100 includes sensors that collect data for generating BSM messages. An RTCM message is GPS correction data used by an RTK module that encapsulates RTCM differential corrections for GPS and other radionavigation signals, as defined in the RTCM Special Committee for Radio Services Committee DSRC media, and then defines a final It can be reconstructed into the expected format. Contains information that is directly used in various positioning systems in accordance with the RTCM standard to increase the absolute and relative accuracy estimates produced. The RTCM information is information that corrects the location information of each object so that the exact location can be known. The transmitter 121 according to the present invention may further include a BSM generation module or RTCM generation module for generating a BSM or RTCM message. RTCM information is encoded and generated as RTCM, which is an international standard message protocol, in the V2X RSU 200 (Roadside Base Station) and transmitted to each vehicle 100 through V2X communication. When the RTCM message is out of the transmission range of the roadside device, smooth delivery becomes difficult. The packet according to the present invention includes hopping information so that each vehicle 100 serves as a router to deliver the BSM message or the RTCM message to the final destination so that it can smoothly arrive at the final destination. For example, in the case of RTCM provided by the V2X RSU 200, the data provision area is generally 500 meters in radius of the roadside device, but when RTCM is transmitted using hopping according to the present invention, the data provision area is several times larger than this. can do. The same is true for BSM messages.

The generating unit 1211 may include a packet containing hopping information in a BSM message or RTCM message (hereinafter referred to as 'message'). Each header of the BSM message or RTCM message may further include an extended information header. Extension information added in each message is recorded in the extension information header. The extension information header may include hopping information according to the present invention, and may further include other additional information.

In summary, the transmitter 121 according to the present invention generates a packet containing hopping information and includes a generator 1211 that includes the packet in a message and a transmitter that transmits the message according to the V2X communication standard according to the hopping information. In the V2X data transmission device 121 including 1213, the message is a Basic Safety Message (BSM) message generated in the vehicle 100 or a Radio Technical Commission for Maritime Services (RTCM) message generated in a roadside base station. The message includes an extension information header included in the packet, and the extension information header includes headers in which the hopping information is recorded. When the packet containing the hopping information is included in the message, the generation unit 1211 also includes slip occurrence information in the message. Accordingly, transmission of the message between vehicles 100 may be performed according to the hopping information, and the vehicle 100 receiving the message may process the message and display slip occurrence information on the HMI 130.

The message includes an extension information header included in the packet, and the extension information header includes a header in which hopping information is recorded, and the header includes a first header, a second header, and a third header. That is, the message generated by the generation unit 1211 according to the present invention includes a packet including a header and a payload, the header includes an extension information header, and the extension information header includes a first header, a second header, and a header. A third header is included.

The first header includes information on the number of remaining hops deducted according to packet transmission according to the V2X module. The remaining hopping count information is deducted by, for example, 1 each time the value included in the maximum hopping count information, which will be described later, is delivered or intermediated by the V2X transmission device 121, and when it becomes 0, the corresponding packet is forwarded. It is information (or value) that disappears from the network without becoming available.

The first header further includes next header information in which the existence of the next header is recorded, version information to identify the version of the corresponding protocol, and information on the remaining time of the packet, i.e., the time a packet can endure until it reaches its final destination. can include The time (value) included in the remaining time information can prevent old messages from remaining in the network.

The second header includes information on the maximum hopping count of the packet. The maximum number of hopping may be set when a first packet is generated. The maximum number of hops is not changed by intermediaries or routers.

The second header further includes transmission method information indicating a transmission method of the packet. Transmission method information may be unicast or topologically-scoped broadcast. In unicast, a specific destination is determined, and messages are delivered by hopping until the message is relayed to the destination. The unicast method can be used when relaying BSM messages. The topological method is a method of mediating messages until the number of remaining hopping counts is exhausted. The topological method can be used when relaying RTCM messages.

The second header further includes next header information in which whether or not the next header exists is recorded, class information in which whether or not the device receiving the relayed message has a corresponding message when there are no neighbors around the device, and length information of the packet excluding the header are further included. can include

A third header includes identification information of the packet. Identification information is information used when detecting duplicate packets. The identification information may be a serial number of the packet. The third header further includes original source information indicating information of a device that generated the packet in addition to the identification information. The initial source information may be a serial number of a device that generated the packet. The identification information and the first source information are used when determining whether the corresponding packet is the same as the previously received packet when the receiving device receives the packet, which will be described later.

The third header further includes final destination information of the packet when the transmission method of the packet included in the second header is unicast. In the unicast method, a message is delivered to a specific destination, and information on the specific destination is included in the third header.

In summary, the extension information header includes a first header, a second header, and a third header, and the first header stores information on the number of remaining hopping counts deducted according to transmission of the packet and the remaining time of the packet. lifetime information, the second header includes information on the maximum hopping count of the packet and transmission method information indicating a transmission method of the packet, and the third header includes identification information of the packet and information about the packet It includes the information of the initial source indicating the information of the device that generated the . If the transmission method of the packet included in the second header is unicast, the third header further includes final destination information of the packet.

The transmission unit 1213 according to the present invention transmits the packet generated by the generation unit 1211 and included in the message to another V2X receiving device 123. That is, the transmission unit 1213 transmits the message to the reception device 123 mounted in the other vehicle 100. When transmitting a message including a packet, the transmitter 1213 may transmit the message to another vehicle 100 or object equipped with the V2X receiver 123. When transmitting a message, the transmitter 1213 may encrypt and transmit the message.

The V2X data receiving device 123 according to the present invention includes a receiving unit 1231 receiving the message transmitted by the transmitting unit 1213, a processing unit 1233 processing the message, and a V2X communication standard message according to hopping information. to the V2X data receiving device 123 mounted in another vehicle 100, including a retransmitter 1235 that transmits the slip occurrence information to another vehicle 100 to prevent traffic accidents such as collisions and accidents. prevent.

The V2X data receiving device 123 (hereinafter, 'receiving device 123') according to the present invention includes a basic safety message (BSM) message generated in the vehicle 100 and a radio RTCM (RTCM) generated in the V2X RSU 200. Technical Commission for Maritime Services) messages, the receiving unit 1231 receiving a packet containing hopping information, the processing unit 1233 processing the packet, and the packet according to the V2X communication standard according to the hopping information. A retransmission unit 1235 for retransmission is included.

The reception unit 1231 according to the present invention receives a message transmitted by the transmission unit 1213 of the transmission device 121 . The message received by the reception unit 1231 is processed by the processing unit 1233. The message received by the receiver 1231 includes a packet containing hopping information. A packet includes a first header, a second header, and a third header, and information included in each header is as described above.

The processing unit 1233 according to the present invention first determines whether extension information is included in the received message. Extended information, as described above, may be included in the extended information header of the message, and when additional information is recorded in the message, it is recorded in the extended information. The extended information may include hopping information according to the present invention, or additional information other than hopping information may be recorded. Accordingly, when the extension information is included in the header of the message, the processing unit 1233 processes (decrypts) the received message with the possibility that there may be hopping information according to the present invention.

The processing unit 1233 according to the present invention processes the header of the received message and extracts hopping information of the packet. As described above, the hopping information includes information included in the first header, the second header, and the third header. First, the processing unit 1233 checks the remaining time information of the first header and deletes the corresponding packet when the remaining time is 0. If the remaining time information is not 0, the processing unit 1233 checks the transmission method information of the second header.

If the transmission method information recorded in the second header is a unicast method, it is checked whether the corresponding packet is a duplicate packet with a previously received packet (or a message duplicated with a previously received message). At this time, the identification information of the third header and the first source information are used. It is determined whether it is a duplicate packet by comparing whether the identification information and the first source information recorded in the corresponding packet are the same as the identification information and the first source information recorded in the previously received packet. In the case of a duplicated packet, the message including the corresponding packet is deleted, and in the case of a non-redundant packet, the final destination information recorded in the third header of the corresponding packet is extracted. When the final destination information and the received information of the receiving device match, the entire message is processed and stored in the database of the receiving device 123. If the final destination information and the received information of the receiving device do not match, the value of the remaining hopping count information recorded in the first header of the corresponding packet is subtracted by one. If the subtracted remaining hopping count information is 0, the corresponding packet and message are deleted. If the subtracted remaining hopping count information is not 0, the corresponding packet and message are retransmitted to another V2X receiving device 123 by the retransmitter 1235, which will be described later. That is, if the remaining hopping count information is not 0, the remaining hopping count is deducted and the message is retransmitted. As described above, when the transmission method of the message is the unicast method, the corresponding message is preferably a BSM message.

If the transmission method information recorded in the second header is a topological method, it is checked whether the corresponding packet is a duplicate packet with a previously received packet (or a message duplicated with a previously received message). At this time, the identification information of the third header and the first source information are used. It is determined whether it is a duplicate packet by comparing whether the identification information and the first source information recorded in the corresponding packet are the same as the identification information and the first source information recorded in the previously received packet. In the case of duplicated packets, the message including the corresponding packet is deleted, and in the case of non-redundant packets, the entirety of the corresponding message is processed and stored in the database of the receiving device 123. In the case of the topological method, unlike the unicast method with a specific final destination, if the remaining hopping count is not 0 even after message processing, the received message is retransmitted to another V2X receiving device 123. Therefore, after processing the message, the remaining hopping count information (value) recorded in the first header is subtracted by 1, and if the remaining hopping count information becomes 0, the corresponding message is deleted. If the remaining hopping count information is not 0, another V2X It is retransmitted to the receiving device 123. That is, if the remaining hopping count information is not 0, the remaining hopping count is deducted and the message is retransmitted.

In summary, when processing the safety message, the processing unit 1233 of the receiving device 123 determines whether or not the extended information header exists in the safety message, and as a result of determining whether the extended information header exists, the safety message If the extension information header does not exist in the message, the safety message is not processed any more, and if the extension information header exists in the safety message as a result of determining whether or not the extension information header exists, the safety message is not processed any more. extracts the extension information header from a message, extracts the packet from the extracted extension information header, extracts the header from the extracted packet, and extracts the transmission method information from a second header of the extracted header; , Determine the transmission method of the packet based on the extracted transmission method information, and as a result of the determination of the transmission method, if the transmission method of the packet is a unicast method, the final destination from the third header of the extracted header As a result of extracting information, determining whether the final destination of the message received based on the extracted final destination information is the V2X data receiving device 123, and determining whether the final destination is the V2X data receiving device 123, the When the final destination of the received safety message is the V2X data receiving device 123, the received safety message is stored in a database and the slip occurrence information is transmitted to another vehicle 100 or the other vehicle 100 receives the information Traffic accidents such as rear-end collisions can be prevented by increasing the processing speed of extracting slip occurrence information included in safety messages when processing messages.

The retransmission unit 1235 according to the present invention retransmits the packets generated by the generation unit 1211 and included in the message to the receiving device 123 mounted in the other vehicle 100. That is, the retransmitter 1235 transmits the message to the other receiving device 123. When transmitting a message including a packet, the retransmitter 1235 may transmit the message to another vehicle 100 or object equipped with the V2X receiving device 123 . The retransmitter 1235 deducts the aforementioned remaining number of hopping counts each time it transmits a packet.

The retransmitter 1235 according to the present invention retransmits the received message to another V2X receiving device 123 when the subtracted remaining hopping count information is not 0. That is, the receiving device 123 serves as the transmitting device 121 . As shown in FIG. 1, the receiving devices 123 subsequent to the first transmitting device 121 perform the role of the transmitting device 121 acting as a router until the remaining hopping count information becomes 0. . The retransmitter 1235 transmits a packet and a message including the packet according to the V2X communication standard according to hopping information such as the remaining number of hoppings. That is, the packet and the message including the packet may be transmitted between the V2X data transmission devices 121 until the remaining hopping count becomes 0 and arrive at the final destination.

In summary, the receiving device 123 according to the present invention includes a receiving unit 1231 receiving a message including a packet including hopping information, a processing unit 1233 processing the message, and a V2X communication standard according to the hopping information. In the V2X data receiving device 123 including the retransmitting unit 1235 for retransmitting the message, the message is a Basic Safety Message (BSM) message generated in the vehicle 100 or a Radio RTCM (RTCM) message generated in the roadside device. Technical Commission for Maritime Services) message, the message includes an extension information header included in the packet, the packet includes an extension information header in which the hopping information is recorded, and the extension information header includes a first a header, a second header, and a third header, wherein the first header includes information on the number of remaining hopping counts deducted according to transmission of the packet and lifetime information in which the remaining time of the packet is stored; The header includes maximum hopping count information of the packet and transmission method information indicating the transmission method of the packet, and the third header includes identification information of the packet and first source information indicating information of a device that generated the packet. and final destination information of the packet, wherein the processing unit 1233, when processing the message, determines whether or not the extended information header exists in the message, and as a result of determining whether the extended information header exists, the message If the extension information header does not exist in the message, processing of the message is not performed any longer, and if the extension information header exists in the message as a result of determining whether or not the extension information header exists, the extension information header is present in the message. An information header is extracted, the packet is extracted from the extracted extended information header, the header is extracted from the extracted packet, the transmission method information is extracted from a second header of the extracted header, and the extracted determining the transmission method of the packet based on the transmission method information, and extracting the final destination information from a third header of the extracted header when the transmission method of the packet is a unicast method as a result of the determination of the transmission method; , It is determined whether the final destination of the received message is the receiving device 123 based on the extracted final destination information, and as a result of determining whether the final destination is the receiving device 123, the final destination of the received message is the In the case of the receiving device 123, the received message is stored in a database.

On the other hand, when the retransmitter 1235 according to the present invention transmits the message in the V2X communication standard according to the hopping information, as a result of determining whether the final destination is the receiving device 123, the final destination of the received message If is not the receiving device 123, extracts the remaining hopping count information from the first header of the extracted header, subtracts 1 from the value of the extracted remaining hopping count information, and subtracts the subtracted remaining hopping count information. If the information value is not 0, the received message is retransmitted to another receiving device 123.

The transmitting device 121 and the receiving device 123 according to the present invention may be integrated and operated as one device, which may be a multi-hop type V2X OBU 120, a V2X communication module, or a V2X module. In addition, the V2X data transmission device 121 and the V2X data reception device 123 may be included in the vehicle 100, a base station including a roadside base station (V2X RSU 200), etc., respectively.

The V2X RSU 200 according to the present invention is installed on the roadside and may be a hybrid V2X RSU 200 for supporting both the WAVE method and the C-V2X method, which are V2X communication methods. The V2X communication standard described in this specification may be a known one, and as an embodiment, it may be Wireless Access for Vehicular Environment (WAVE) made of IEEE 802.11p and IEEE 1609.x standards, but is not limited thereto, and for example, C -It could be V2X.

The hybrid V2X RSU 200 according to the present invention includes a C-V2X module and a WAVE module. The vehicle 100 according to the present invention is equipped with a C-V2X transmitter 121 and a C-V2X receiver 123 (hereinafter referred to as 'C-V2X OBU 120') for C-V2X communication or WAVE communication A WAVE transmission device 121 and a WAVE reception device 123 (hereinafter referred to as 'WAVE OBU') are installed.

The C-V2X module included in the hybrid V2X RSU 200 according to the present invention communicates with the C-V2X OBU 120 installed in the vehicle 100 to transmit and receive data, and the hybrid V2X RSU 200 according to the present invention The included WAVE module communicates with the WAVE OBU 120 installed in the vehicle 100 to transmit and receive data. The hybrid V2X RSU 200 according to the present invention can simultaneously communicate with the C-V2X OBU 120 and the WAVE OBU 120 installed in the vehicle 100.

The C-V2X module according to the present invention includes an LTE-V2X module and/or a 5G-V2X module. The C-V2X module includes an LTE-V2X antenna and/or a 5G-V2X antenna for transmitting and receiving a C-V2X signal including an LTE-V2X signal and/or a 5G-V2X signal. The C-V2X module demodulates the LTE-V2X signal and / or 5G-V2X signal received by the LTE-V2X antenna and / or 5G-V2X antenna to obtain LTE-V2X communication information and / or 5G-V2X communication information, It includes a C-V2X modem that modulates the obtained LTE-V2X communication information and / or 5G-V2X communication information to generate an LTE-V2X signal and / or a 5G-V2X signal.

The WAVE module according to the present invention includes a WAVE antenna for transmitting and receiving a WAVE-V2X signal. The WAVE module includes a WAVE modem that demodulates the WAVE-V2X signal received by the WAVE antenna to obtain WAVE communication information and modulates the WAVE communication information to generate a WAVE signal.

WAVE and C-V2X have different protocol stacks and data modulation methods. When the frequencies used for the C-V2X OBU 120 and the WAVE OBU are different from each other, there is no mutual influence even if they are used simultaneously. Therefore, the hybrid V2X RSU 200 according to the present invention includes a C-V2X module and a WAVE module, and as the C-V2X and WAVE communicate with the vehicle 100 using different frequencies at the same time, the C-V2X method and WAVE-type V2X communication are all possible.

The hybrid V2X RSU 200 according to the present invention may collect communication information obtained by the C-V2X module and the WAVE module or signals modulated based on the communication information and transmit the collected signals to the center server (not shown). The hybrid V2X RSU 200 may transmit the collected data to the center server using 5G communication. Based on the received data, the center server generates information for operating the roadside base station, information for driving the vehicle 100, and additional information, and transmits the generated information to the hybrid V2X RSU 200 according to the present invention. can do. The center server according to the present invention may be a central control center server.

The hybrid V2X RSU 200 according to the present invention transmits information received from the center server to the vehicle 100. When the hybrid V2X RSU 200 transmits information received from the sensor server to the vehicle 100, the information modulated by the C-V2X module is sent to the vehicle 100 equipped with the C-V2X OBU 120, and the WAVE module The information modulated by may be controlled to be transmitted to the vehicle 100 equipped with the WAVE OBU.

The hybrid V2X RSU 200 according to the present invention further includes a 5G module that transmits the collected processed data to the center server through the 5G network and receives information generated by the center server through 5G communication. The 5G module includes a 5G antenna for transmitting and receiving 5G signals and a 5G modem for processing the 5G signals received through the 5G antenna. The 5G module obtains information for operation of the roadside base station, information for operation of the vehicle 100, and additional information from the center server through 5G communication, and transmits the aforementioned C-V2X communication information and WAVE communication information through 5G communication. sent to the center server. The 5G module supports 5G communication. The 5G module connects the network and terminals for 5G wireless communication service.

The hybrid V2X RSU 200 may transmit roadside base station surrounding information to the vehicle 100 and the center server through 5G communication. The information about the roadside base station may include information on the vicinity of the roadside base station collected by the corresponding roadside base station and/or information about the vehicle 100 within the area of the corresponding roadside base station. When the 5G module transmits C-V2X communication information and WAVE communication information to the center server through 5G communication, it can also transmit information around the base station to the center server.

The hybrid V2X RSU 200 according to the present invention, as an embodiment, performs basic vehicle-to-vehicle communication (V2V, Vehicle to Vehicle) using a C-V2X module, and performs vehicle and infrastructure communication (V2I) using a WAVE module. , Vehicle to Infrastructure) can be performed.

The hybrid V2X RSU 200 according to the present invention further includes a GNSS module that processes GNSS signals to obtain location information of roadside base stations, and the GNSS module includes a GNSS antenna for transmitting and receiving GNSS signals. The GNSS module processes the GNSS signal received by the GNSS antenna to obtain location information of the roadside base station.

On the other hand, V2X communication is a service that can reduce traffic accidents and traffic congestion by providing vehicle safety services in a wireless environment, detecting risks that may occur while driving in advance and notifying the driver.

V2X communication, as described above, generally uses WAVE (Wireless Access in Vehicular Access) technology. WAVE technology is a short-distance wireless communication standard technology that supports a communication distance of 1 km and a communication speed of at least 1 Mbps to a maximum of 54 Mbps. WAVE technology is a technology for communication between vehicles 100 moving at high speed, and requires transmission of individual broadcast messages in a very short wireless access time. In addition, multiple channels (7 channels) and variable transmit power are supported, and direct communication between vehicles 100 is possible through multiple overlapping communication areas and quick initialization.

The vehicle safety service is based on the WAVE standard, which is a short-range wireless communication standard between vehicles 100, and transmits a safety message (Basic Safety Message, BSM) through communication between vehicles 100 (Vehicle-to-Vehicle, V2V) to nearby vehicles ( 100) by broadcasting periodically. However, due to the nature of communication between vehicles 100 being broadcast, excessive traffic is generated in the network in an area where vehicles 100 are concentrated, such as an intersection or a highway in a city, which drastically reduces the transmission failure probability and delay of the safety message. increase

Therefore, in the present invention, in order to solve the communication congestion problem occurring in the process of performing the vehicle 100 safety service, the relationship between the Channel Busy Ratio and the number of vehicles 100 is mathematically approximated, and the overall network congestion is estimated using this. do. And based on this, we propose a transmission power control algorithm that controls the data transmission power of the V2X module.

The transmitting unit 1213 or the retransmitting unit 1235 according to the present invention measures the congestion level by observing the channel load in order to measure the congestion level of the network or channel. In the present invention, a concept called Channel Busy Ratio (CBR) is introduced to observe channel load. The channel load tends to increase as the number of nodes that perform communication at a close distance, that is, the number of surrounding vehicles 100 increases. Since the channel load tends to increase as the number of nodes communicating at a close distance, that is, the number of surrounding vehicles 100 increases, it can be said that analyzing the relationship between CBR and the number of surrounding vehicles 100 is meaningful. In the present invention, the relationship between the CBR and the number of surrounding vehicles 100 is mathematically approximated and the overall network congestion is estimated using this. In the present invention, since problems such as hidden node problem and exposed node problem occur between nodes within a two-hop distance in a wireless ad-hoc communication environment, the total network congestion is defined as a two-hop network congestion.

CBR is a ratio of the degree to which a channel is utilized within a safety message transmission period. CBR, as shown in Equation 1, may be defined as a value obtained by dividing the transmission/reception time (tT, tR) of a packet by the safety message transmission period (T). In the present invention, CBR is used as an index indicating how congested a channel is.

(Equation 1)

The number of nearby vehicles 100 (Remote Vehicle, RV) is the number of vehicles 100 within a 1-hop communication distance of the host vehicle 100 (HV), and the number of vehicles 100 within a distance capable of communicating with the HV. means number. In the present invention, in order to organize the relationship between the CBR and the number of surrounding vehicles 100, a virtual time slot is introduced by applying a modified concept of a virtual time frame (VTF) of S. Bai thesis. The size of a virtual time slot (Ss) is the time required to transmit or receive one safety message, and the number of virtual time slots (Sn) is the maximum number of times a safety message can be transmitted and received during a safety message transmission period (T). . Therefore, the size of the virtual time slot is the size of the safety message (M) divided by the communication speed (C), and the number of virtual time slots is the safety message transmission period divided by the size of the virtual time slot. If this is expressed as a formula, it is the same as (Equation 2, 3).

(Equation 2)

(Formula 3)

For example, if the safety message size is assumed to be 400 bytes and the safety message broadcast cycle is fixed at 100 ms, the size of one virtual time slot is approximately 1.08 ms based on a communication speed of 3 Mbps, and the number of virtual time slots is It is about 93.

Since CBR is the rate at which the channel is utilized within the safety message transmission period, the product of the virtual time slot size, the number of virtual time slots, and the probability that one virtual time slot will be used (p) is divided by the safety message transmission period (T) (Equation 4) can be expressed as

(Formula 4)

Here, the probability that one virtual time slot is not used is expressed as (Equation 5) when the number of RVs within one hop distance is N. Therefore, CBR can be approximated by (Equation 6).

(Formula 5)

(Formula 6)

Figure 1 is a table showing the communication distance per data transmission power of the V2X module according to the present invention, Figure 2 is a pseudo code of the data transmission power control algorithm of the V2X module according to the present invention.

<Figure 1>

<Figure 2>

In the present invention, an algorithm for adjusting the data transmission power of the V2X module provided by the transmitter 121 or the receiver 123 based on the degree of congestion is proposed. The transmission unit 1213 further includes a congestion maintenance unit (not shown) that calculates the degree of congestion (CBR2hop) of the network or channel, and increases or decreases the transmission power (TX Power) based on the congestion level to keep the channel load constant. As shown in Figure 1, it is assumed that the communication distance per transmit power is known. Figure 2 is the pseudo code of the proposed algorithm.

In order to estimate the overall network congestion (CBR2hop), the congestion maintenance unit uses the CBR (CBR1hop) of 1 hop distance and the TX Power information received from all neighboring RVs. If this is written as a formula, it is the same as (Formula 7). Here, CBR1hop is a value actually measured by the HV, and Rd is the density of vehicles 100 around the RV calculated using TX Power information received from neighboring RVs. OA is the area where the communication radii of RV and HV overlap.

(Formula 7)

(Equation 8)

(Formula 9)

Rd is the density of surrounding vehicles 100, and the number of surrounding vehicles 100 of the RV is divided by the 2-hop communication range (TX_Area2hop), where the number of surrounding vehicles 100 can be calculated through (Equation 9), which is an inverse function of (Equation 6). can This is possible because it is assumed that CBR2hop is always maintained at 0.5 by the proposed algorithm. When calculating Rd of all RVs in HV as shown in (Equation 7), considering overlapping communication ranges between RVs, the complexity of the algorithm for calculating CBR2hop becomes O(2n). Therefore, in the present invention, CBR2hop was estimated by sampling eight RVs farthest from the east, west, south, north, northeast, northwest, southeast, and southwest of HV.

Figure 3 is a table showing the simulation environment for verifying the algorithm proposed in the present invention.

<Figure 3>

The simulation to verify the algorithm proposed in the present invention was performed for 30 seconds in a two-lane, 3km highway environment as shown in Figure 3. Nodes were run in a static environment that did not move. In addition, a case where the data transmission power control algorithm according to the present invention is not applied (TPC Off) and a case where it is applied (TPC On) are divided into simulations. In a scenario in which the transmission power control algorithm is not applied, the transmission power of the vehicle 100 remains at 15.0 dBm, and the initial transmission power when the algorithm is applied is 15.0 dBm.

To evaluate the performance of the proposed 2-hop congestion estimation-based safety message transmission power control algorithm, two are evaluated. Whether the congestion of 2 hops is correctly estimated and whether the congestion is alleviated in safe message transmission by adjusting the transmit power. For this purpose, the performance indicators of Ideal CBR2hop, Estimated CBR2hop, CBR1hop, and PER are used.

Ideal CBR2hop calculates 2-hop CBR by directly sharing CBR measured in simulation by all nodes, Estimated CBR2hop estimates 2-hop CBR using TX Power shared through the algorithm proposed in the present invention, and CBR1hop is a unit The higher the degree of use of the channel during the time, the higher the utilization rate of the channel is, and the lower the PER is the ratio of error-occurring packets among the packets received during the unit time, the higher the communication reliability.

Figure 4 is a table showing parameter values for performance evaluation of the data transmission power control algorithm according to the present invention, Figure 5 is a graph comparing the average values calculated by all vehicles 100 in the simulation, Figure 6 is the time This is a graph comparing Ideal CBR2hop and Estimated CBR2hop in the free scenario according to

<Figure 4>

<Figure 5>

<Figure 6>

In the present invention, the performance of the proposed context-awareness-based transmit power control algorithm is verified through simulation. The simulation was performed using Qualnet, a network simulator, and the parameter values are shown in Figure 4.

Ideal CBR2hop and Estimated CBR2hop were compared to verify whether the overall network congestion was properly estimated. Figure 5 is a comparison of the average values calculated by all vehicles 100 in the simulation, and it can be seen that they are estimated similarly in the Medium or Free scenarios except for the Heavy scenario. The reason why it is not similarly estimated in the heavy scenario is that the proposed algorithm assumes that CBR2hop is distributedly maintained at 0.5 in each vehicle 100 . However, since this assumption cannot be satisfied in the heavy scenario, Estimated CBR2hop also inevitably generates a lot of errors. Figure 6 compares Ideal CBR2hop and Estimated CBR2hop in the free scenario over time, and it can be seen that the estimation is almost perfect.

Figure 7 is a graph comparing Packet Error Rate (PER) when the algorithm according to the present invention is applied and when it is not applied, and Figure 8 is a 1-hop Channel Busy when the algorithm according to the present invention is applied and when it is not applied. Ratio (CBR1hop) This is a graph comparing V2X modules according to the distribution density.

<Figure 7>

<Figure 8>

In order to evaluate the performance of the proposed algorithm, the case where the algorithm was applied and the case where it was not applied were simulated and compared according to the density in which the Packet Error Rate (PER) and 1-hop Channel Busy Ratio (CBR1hop) vehicles 100 are distributed. Figures 7 and 8 are the results. According to Figure 7, when the proposed algorithm is applied (TPC ON), the packet error rate shows an error rate of 0.1 or less in all scenarios, and when the proposed algorithm is not applied (TPC OFF), the packet error rate is 0.1 in the heavy scenario. show excess. This shows that the proposed algorithm effectively reduces the packet error rate and increases the reliability of V2V communication in a congested situation.

Referring to Figure 8, when the proposed algorithm is applied in Heavy and Medium scenarios, CBR1hop is lower and higher in Free scenarios than when it is not. Through this, the proposed algorithm reduces channel utilization by reducing transmit power in scenarios with high congestion (Heavy, Medium), but increases communication reliability by reducing PER, and increases transmit power in scenarios with small congestion (Free). It shows that communication efficiency is increased by increasing channel utilization.

In conclusion, it is possible to estimate the overall network congestion using CBR (Channel Busy Ratio), and based on this, we propose a transmission power control algorithm that controls transmission power. The proposed algorithm uses the TX　Power field in the header of the WSMP message to estimate the overall network congestion, and based on this, controls the transmit power to maintain the overall network congestion constant. As a result of the simulation through Qualnet, the estimation of the overall network congestion was accurately performed, and the transmission power control algorithm showed that the reliability of communication between vehicles 100 was increased by lowering the packet error rate.

Data packets according to the present invention are generated (transmitting end) and processed (receiving end) in the application layer (layer). Therefore, when a data packet is created, productivity can be improved because it can be created without worrying about packet communication or subsequent modifications.

In this specification, the slip state detection unit 110, the slip occurrence determination module 119, the generation unit 1211, the transmission unit 1213, the reception unit 1231, the processing unit 1233, and the retransmission unit 1235 are sequentially stored in the memory. It can be processors that execute processes. Or, it can operate as software modules driven and controlled by a processor. Further, a processor may be a hardware device.

In this specification, a "unit" includes a unit realized by hardware, a unit realized by software, and a unit realized using both. Further, one unit may be realized using two or more hardware, and two or more units may be realized by one hardware.

The protection scope of the present invention is not limited to the description and expression of the embodiments explicitly described above. In addition, it is added once again that the scope of protection of the present invention cannot be limited due to obvious changes or substitutions in the technical field to which the present invention belongs.

100: vehicle 110: slip state detection unit
111: GPS sensor 113: wheel speed sensor
115: steering angle sensor 117: gyro sensor
119: slip occurrence determination module 120: V2X OBU
121: transmission device 1211: generation unit
1213: transmitter 123: receiver
1231: receiving unit 1233: processing unit
1235: retransmission unit 130: HMI
200: V2X RSU

Claims (5)

V2X (vehicle to everything) RSU (Roadside Unit) installed on the roadside; and
A vehicle equipped with a V2X OBU (On Board Unit) that transmits and receives a slip state detection unit and a safety message (BSM, Basic Safety Message) for detecting wheel spin or slip condition of the road surface;
Including,
The slip state detection unit, when the wheel spin or the slip state of the road surface is detected, generates slip generation information and transmits it to the V2X OBU;
The V2X OBU,
After generating the safety message including the received slip occurrence information, the safety message is transmitted to the V2X RSU or a V2X OBU mounted on another vehicle,
The sliding state detection unit,
a GPS sensor for measuring the location and moving speed of the vehicle;
a wheel speed sensor for measuring a wheel rotation speed of the vehicle;
a steering angle sensor for measuring a steering angle of the vehicle;
a gyro sensor for measuring a yaw angle of the vehicle;
a slip occurrence determination module for detecting wheel spin or a slip state of the road surface based on data measured by the GPS sensor, the wheel speed sensor, the steering angle sensor, and the gyro sensor; and
a slip generation information generating unit for generating and transmitting slip generation information to the V2X OBU when the wheelspin or the slip state of the road surface is detected;
Including,
The slip occurrence determination module,
detecting wheel spin by comparing a moving speed of the vehicle with a rotational speed of the wheel;
Comparing the steering angle with the yaw angle to detect a sliding state of the road surface;
After receiving the safety message, the V2X OBU mounted in the other vehicle processes the safety message to extract slip occurrence information and transmits it to the vehicle's HMI (Human-Machine Interface),
The HMI displays the slip occurrence information included in the safety message,
The slip occurrence information includes location information where the slip occurs,
The V2X OBU includes a V2X data transmission device and a V2X data reception device,
The V2X data transmission device,
a generating unit generating a packet containing the safety message and hopping information, and including the packet and the slip occurrence information in the safety message; and
A transmitter for transmitting the safety message to a V2X data receiving device mounted in another vehicle in accordance with the V2X communication standard according to the hopping information,
The V2X data receiving device,
a receiving unit receiving the safety message transmitted by the transmitting unit;
a processing unit processing the safety message; and
Including a retransmitting unit for retransmitting the safety message to a V2X data receiving device mounted in another vehicle according to the hopping information according to the V2X communication standard, characterized in that to prevent a collision accident by transmitting the slip occurrence information to another vehicle , Slip accident prevention system using AI V2X OBU. delete delete delete The method of claim 1,
The safety message includes an extension information header included in the packet,
The extension information header includes a header in which the hopping information is recorded,
The header includes a first header, a second header, and a third header,
The first header includes information on the number of remaining hopping counts deducted according to transmission of the packet and lifetime information in which the remaining time of the packet is stored;
The second header includes information on the maximum hopping count of the packet and transmission method information indicating a transmission method of the packet;
The third header includes identification information of the packet, first source information indicating information of a device that generated the packet, and final destination information of the packet,
When the processing unit processes the safety message,
determining whether the extended information header exists in the safety message;
When the extended information header does not exist in the safety message as a result of determining whether the extended information header exists, processing of the safety message is not performed any longer.
When the extended information header exists in the safety message as a result of determining whether or not the extended information header exists, the extended information header is extracted from the safety message, the packet is extracted from the extracted extended information header, and the extracted Extracting the header from the packet, extracting the transmission method information from a second header of the extracted header, and determining the transmission method of the packet based on the extracted transmission method information;
As a result of determining the transmission method, if the transmission method of the packet is the unicast method, the final destination information is extracted from a third header of the extracted header, and the final destination information of the received message is extracted based on the extracted final destination information. Determining whether the destination is the V2X data receiving device,
As a result of determining whether the final destination is the V2X data receiving device, when the final destination of the received safety message is the V2X data receiving device, the received safety message is stored in a database and the slip occurrence information is transmitted to another vehicle A slip accident prevention system using AI V2X OBU, characterized by preventing collisions by increasing the processing speed of safety messages.

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