WO2021000338A1

WO2021000338A1 - Relay node optimal location selection method applied to internet of vehicles curved path scenario

Info

Publication number: WO2021000338A1
Application number: PCT/CN2019/095381
Authority: WO
Inventors: 曹敦; 蒋宇晨; 王进; 王磊; 廖卓凡
Original assignee: 长沙理工大学
Priority date: 2019-07-02
Filing date: 2019-07-10
Publication date: 2021-01-07
Also published as: CN110446179A; CN110446179B

Abstract

A relay node optimal location selection method applied to an Internet of Vehicles curved path scenario. The method comprises: obtaining obstruction parameters of a target obstruction within a communication area of a vehicle (S100); calculating tangent lines between the vehicle and the boundary of the obstruction according to the obstruction parameters, and obtaining all primary intersection points, within the communication area of the vehicle, at which the tangent lines intersect with a curved path (S200); obtaining all secondary intersection points, unobstructed by the target obstruction, at which the boundary of the communication area of the vehicle intersects with the curved path (S300); selecting a relay node optimal location from among all the primary intersection points and all the secondary intersection points (S400). Communication between the vehicle and the relay node optimal location selected by means of the present method will not be obstructed by the target obstruction, so that during a subsequent process wherein the relay node optimal location acts as a center for iteratively selecting relay nodes, the segmentation time can be reduced, and the generation of larger random contention delays can be avoided. When there is an obstruction affecting signal propagation in an Internet of Vehicles curved path scenario, the present method can effectively decrease the overall delay in broadcasting the selection of a relay node.

Description

Method for selecting optimal position of relay node applied to car network curve scene

Technical field

The invention relates to the field of vehicle networking communication technology, and in particular to a method for selecting the optimal position of a relay node applied to a vehicle networking curve scene.

Background technique

With the development of communication technology, the Internet of Vehicles technology has approached people's lives. The V2V communication technology in the Internet of Vehicles technology refers to the technology that establishes direct communication between vehicles and realizes the transfer and sharing of information between vehicles. The technology is applied to the transportation system, which can help improve the transportation efficiency of the transportation system. When used in vehicles, it can warn the driver or automatically intervene and interfere with the driving operation of the vehicle before the accident occurs, effectively avoiding the accident or reducing the accident. The chain effect brought by the latter, and compared with the vehicle-to-vehicle communication established by the cellular network, has the advantages of small transmission delay and low cost.

In V2V communication technology, because the range of direct communication between vehicles is limited, when the destination of the message is beyond the communication range of the vehicle, the transmission of the message needs to be relayed by vehicles within its communication range to cover the communication range. In areas farther away, the vehicle that relays the message is called a relay node, and the relay node is selected based on the determined optimal location of the relay node. Therefore, determining the optimal location of a reasonable and reliable relay node is a prerequisite for selecting the optimal relay node, and it is also one of the most important research issues in the field of V2V communication technology.

At present, V2V communication technology can only be divided into the following two types:

The first method is to determine the optimal position of the relay node through the beacons (BEACON) transmitted by neighboring nodes in real time, and then select the technology of the relay node. Due to the large number of vehicles, in order to avoid excessive channel load, the BEACON cycle time interval Not too small, generally 100ms. However, this will cause poor real-time position information and increase the load in a communication network with a higher vehicle density.

The second method is to determine the optimal location of the relay node first, and then select the relay node with the help of black-burst. The black-burst technology can overcome the technical shortcomings of BEACON based on the first method, but because The lack of reasonable consideration for obstacles hindering the message dissemination leads to the iterative selection of relay nodes by determining the optimal location of the relay node, which is very likely to consume more partition time and generate greater random contention delay. This leads to high latency.

In summary, choosing the optimal location of a reasonable and reliable relay node is a prerequisite for selecting the optimal relay node. Therefore, how to choose a reasonable and reliable relay in a car network curve scene where obstacles hinder signal propagation The optimal location of nodes is an urgent problem in the current V2V communication technology.

Summary of the invention

The purpose of the present invention is to solve at least one of the technical problems existing in the prior art, and to provide a method for selecting the optimal position of a relay node applied to a curve scene of a car network.

The first aspect of the present invention provides a method for selecting the optimal position of a relay node applied to a curve scene in a network of vehicles, including the following steps:

Obtain the obstacle parameters of the target obstacle in the communication area of the vehicle;

Calculate a tangent line between the vehicle and the boundary of the obstacle according to the obstacle parameter, and obtain all the first intersection points where the tangent line and the curve intersect in the communication area of the vehicle;

Acquiring all secondary intersection points where the boundary of the communication area of the vehicle intersects the curve and is not obstructed by the target obstacle;

The optimal position of the relay node is selected among all the primary intersections and all the secondary intersections.

According to the method for selecting the optimal position of a relay node applied to a curve scene of a connected car according to the first aspect of the present invention, the acquisition of the vehicle's communication area boundary and the curve is not obstructed by the target All the second intersection points obstructed by objects include the following steps:

Acquiring an obstruction area of the target obstacle formed between the vehicle and the tangent line;

Obtain all intersection points where the communication area boundary of the vehicle intersects the curve, and select all secondary intersection points that are not in the obstructed area from all the intersection points.

According to the first aspect of the present invention, a method for selecting the optimal position of a relay node applied to a car network curve scene, wherein the relay node is selected from all the primary intersections and all the secondary intersections The optimal location includes the following steps:

Calculate the path distance from all the primary intersections and all the secondary intersections along the curve to the end of the message propagation;

Among all the primary intersections and all the secondary intersections, the intersection with the closest path distance is selected as the optimal position of the relay node.

According to the method for selecting the optimal position of the relay node applied to the car network curve scene according to the first aspect of the present invention, the relay node is calculated among all the primary intersections and all the secondary intersections After the optimal position, the following steps are included:

Select an iterative algorithm to perform iterative partitioning with the optimal position of the relay node as the center, and determine the candidate interval;

Random contention is performed on candidate nodes in the candidate interval, and the candidate node that completes the contention first is used as a relay node.

According to the first aspect of the present invention, a method for selecting an optimal position of a relay node applied to a curve scene of a connected car, the iterative algorithm includes an exponential iterative algorithm.

According to the first aspect of the present invention, a method for selecting an optimal position of a relay node applied to a curve scene of a car network, the relay node includes a mobile platform with communication capabilities or a fixed platform with communication capabilities.

In a second aspect of the present invention, there is provided a device for selecting the optimal position of a relay node applied to a car network curve scene, including the following units: an obstacle parameter receiving unit, a primary intersection acquiring unit, a secondary intersection acquiring unit, and The optimal position selection unit of the relay node;

The obstacle parameter receiving unit is used to obtain the obstacle parameter of the target obstacle in the communication area of the vehicle;

The primary intersection acquiring unit is configured to calculate the tangent between the vehicle and the boundary of the obstacle according to the obstacle parameter, and acquire all primary intersections where the tangent and the curve intersect in the communication area of the vehicle;

The secondary intersection point acquiring unit is configured to acquire all secondary intersection points where the boundary of the communication area of the vehicle and the curve intersect and are not hindered by the target obstacle;

The optimal position selection unit of the relay node is used to select the optimal position of the relay node from all the primary intersections and all the secondary intersections.

According to the second aspect of the present invention, the device for selecting the optimal position of the relay node applied to the curve scene of the Internet of Vehicles further includes the following units: a candidate interval selection unit and a relay node selection unit;

The candidate interval selection unit is configured to select an iterative algorithm to perform iterative partitioning with the optimal position of the relay node as the center, and determine the candidate interval;

The relay node selection unit is used to randomly compete for candidate nodes in the candidate interval, and use the candidate node that completes the contention first as the relay node.

In a third aspect of the present invention, there is provided a device for selecting the optimal position of a relay node in a vehicle network curve scene, including at least one control processor and a memory for communicating with the at least one control processor The memory stores instructions that can be executed by the at least one control processor, the instructions are executed by the at least one control processor, so that the at least one control processor can execute as described in the first aspect of the present invention A method for selecting the optimal position of a relay node applied to a curve scene of a car network is described.

In a fourth aspect of the present invention, a computer-readable storage medium is provided, characterized in that: the computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are used to make a computer execute the On the one hand, a method for selecting the optimal position of a relay node applied to a curve scene of an Internet of Vehicles is described.

The present invention has at least the following beneficial effects:

This method first obtains the obstacle parameters in the communication area of the vehicle, and then makes the tangent line between the vehicle and the obstacle boundary, and obtains all the intersection points of the tangent line and the curve, and then calculates the intersection of the vehicle communication area boundary and the curve For all the secondary intersections that are not obstructed by the target obstacle, finally select an intersection from all primary intersections and all secondary intersections as the optimal position of the relay node. The communication between the optimal position of the relay node selected by the method of the prior art and the vehicle may be hindered by the target obstacle, resulting in greater random contention when the relay node is selected subsequently through the optimal position of the relay node Delay; and the communication between the optimal position of the relay node selected by the method of the present invention and the vehicle will not be hindered by the target obstacle, so that the process of selecting the relay node iteratively takes the optimal position of the relay node as the center , Can reduce the partition time and avoid greater random contention delay.

To sum up, this method can effectively reduce the overall delay of broadcast relay node selection when obstacles affect signal propagation in a car network curve scene.

Description of the drawings

The present invention will be further described below in conjunction with the drawings and embodiments;

FIG. 1 is a flowchart of a method for selecting an optimal position of a relay node applied to a curve scene of an Internet of Vehicles according to an embodiment of the present invention;

FIG. 2 is a specific flowchart of step S300 in FIG. 1;

FIG. 3 is a specific flowchart of step S400 in FIG. 1;

FIG. 4 is a flowchart of selecting a relay node according to the optimal position of the relay node in a method for selecting an optimal position of a relay node applied to a curve scene of an Internet of Vehicles according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of selecting an optimal position of a relay node in a method for selecting an optimal position of a relay node applied to a curve scene of an Internet of Vehicles according to an embodiment of the present invention;

6 is a schematic diagram of selecting the relay node according to the optimal position of the relay node in the method for selecting the optimal position of the relay node applied to the curve scene of the Internet of Vehicles according to an embodiment of the present invention;

7 is a reference schematic diagram of selecting the optimal position of a relay node and selecting a relay node according to the optimal position of the relay node in the prior art according to an embodiment of the present invention;

FIG. 8 is a reference schematic diagram of selecting the optimal position of a relay node and selecting a relay node according to the optimal position of the relay node according to the present technology according to an embodiment of the present invention;

FIG. 9 is a schematic structural diagram of a device for selecting an optimal position of a relay node applied to a curve scene of an Internet of Vehicles according to an embodiment of the present invention;

FIG. 10 is a schematic structural diagram of a device for selecting an optimal position of a relay node applied to a curve scene of an Internet of Vehicles according to an embodiment of the present invention.

Detailed ways

V2V communication technology is a communication technology that is not limited to fixed base stations and provides direct end-to-end wireless communication for moving vehicles. V2V communication technology can establish direct communication between cars, realize signal transmission and signal sharing, which can improve the transportation efficiency of the transportation system. However, because the scope of direct communication between vehicles is limited, when the destination of the message is beyond the communication range of the vehicle, the transmission of the message needs to be relayed by the vehicles within its communication range to cover the further area outside the communication range. , The vehicle that relays the message is called a relay node.

The existing technology for selecting a relay node is to first determine the optimal location of the relay node, and then select the relay node by means of a black-burst signal. Although this technology can overcome the shortcomings of traditional technology, the technology lacks reasonable consideration of obstacles hindering signal propagation in curve scenes, resulting in the determination of the optimal position of the relay node and the iterative selection of the relay node. It will consume more partitioning time, generate greater random contention delay, increase the overall delay of relay node selection, and reduce the efficiency of relay node selection. For example, because obstacles hinder the signal propagation, the signal receiver vehicle that broadcasts the blocking signal in the third zone in advance and selects the relay node as the signal receiver cannot receive the request communication packet (RTB) sent by the signal sender vehicle. Four partitions broadcast blocking signals, and then randomly compete to re-select a signal receiver vehicle as a relay node. This will undoubtedly make the partition time-consuming to the maximum. Since the fourth partition has a larger range than the third partition, it will also Generate greater random contention delay.

On the basis of the prior art, the present invention provides a method for selecting the optimal position of a relay node applied to a curve scene of a car network. In a curve scene where obstacles affect signal propagation, the selection of relay nodes can be reduced. The overall delay improves the efficiency of relay node selection.

This section will describe the specific embodiments of the present invention in detail. The preferred embodiments of the present invention are shown in the drawings. The function of the drawings is to supplement the description of the text part of the manual with graphics, so that people can intuitively and vividly understand the text. Each technical feature and overall technical solution of the invention cannot be understood as a limitation on the protection scope of the present invention.

In the description of the present invention, it should be understood that the orientation description involved, for example, the orientation or positional relationship indicated by up, down, front, back, left, right, etc., is based on the orientation or positional relationship shown in the drawings, and only In order to facilitate the description of the present invention and simplify the description, it does not indicate or imply that the pointed device or element must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

In the description of the present invention, several meanings are one or more, multiple meanings are two or more, greater than, less than, exceeding, etc. are understood to not include the number, and above, below, and within are understood to include the number. If it is described that the first and second are only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly specifying the number of the indicated technical features or implicitly specifying the order of the indicated technical features relationship.

Referring to Fig. 1, an embodiment of the present invention provides a method for selecting an optimal location point of a relay node applied to a curve scene of an Internet of Vehicles, including the following steps:

S100. Obtain obstacle parameters of the target obstacle in the communication area of the vehicle;

S200: Calculate the tangent between the vehicle and the boundary of the obstacle according to the obstacle parameters, and obtain all the first intersection points where the tangent and the curve intersect in the communication area of the vehicle;

S300. Obtain all secondary intersection points where the boundary of the communication area of the vehicle intersects the curve and is not obstructed by the target obstacle;

S400: Select the optimal position of the relay node from all the first intersection points and all the second intersection points.

Wherein, in step S100 of this embodiment, the vehicle is both a signal sending end and an information sending vehicle. For example, the vehicle communication area is a circle with a radius of 900 meters. It is understandable that in this embodiment, the communication area of the vehicle and the boundary of the communication area of the vehicle are obtained through the GPS (Global Positioning System) device that comes with the vehicle, and the obstacle parameters are obtained through the vehicle's own GIS (Geographic Information System). ) Obtained by the system. Among them, the obstacle parameter includes at least the relevant information of the obstacle boundary, where the target obstacle may be a building, a large rock, or a mountain.

In step S200 of this embodiment, the vehicle is taken as a starting point and a tangent is drawn toward the boundary of the obstacle. It can be understood that there are at least two tangents. For example, the obstacle is a building, and the building has at least two tangents; All intersections where the curve intersects in the communication area of the vehicle are named as one intersection.

In step S300 of this embodiment, first obtain all the intersection points where the communication area boundary of the vehicle intersects the curve, such as a circle with a radius of 900 meters, and obtain all the intersection points where the arc and the curve intersect. It can be understood that these intersection points There may be communication between the intersection and the vehicle that is blocked by the target obstacle. Therefore, it is necessary to calculate the obstacle area of the target obstacle formed between the vehicle and the tangent in the communication area of the vehicle, and the obstacle that exists in the obstacle area Intersection elimination, for example, there are 5 intersections where the arc and the curve intersect, but 2 are located in the obstructing area. Therefore, to eliminate these 2 intersections, you only need to leave the remaining 3 intersections.

In step S400 of this embodiment, it is necessary to select the optimal position of a relay node among all the first-order intersections and all the second-order intersections. It can be understood that the method for selecting the optimal position of the relay node in the present invention can use European style. Distance, that is, the intersection with the shortest straight line distance from the end of the message transmission among all the first and second intersections is selected as the optimal position of the relay node, and it can also be selected from all the first and second intersections along the curve. The intersection with the shortest path distance from the road to the end of the message propagation is regarded as the optimal position of the relay node. In this embodiment, it is preferable to use the method with the shortest path distance from the intersection along the curve to the end of the message propagation, instead of the Euclidean distance method. It is understandable that, in this embodiment, because it is a curve scene, the purpose is to achieve complete coverage of the curve by the message broadcast, and the purpose of completely covering the curve by the message broadcast is directly expressed in the form of the end of the message transmission. When the coverage reaches the end of the message propagation and there is no uncovered blank area between each hop in the middle, it can be considered that the complete coverage of the message broadcast is achieved on this curve.

Further, referring to FIG. 2, step S300 further includes the following steps:

S301. Obtain the obstruction area of the target obstacle formed between the vehicle and the tangent in the communication area of the vehicle;

S302. Obtain all intersection points where the boundary of the communication area of the vehicle intersects the curve, and select all secondary intersection points that are not in the obstructed area from all the intersection points.

First obtain all the intersection points where the vehicle's communication area boundary and the curve intersect, such as a circle with a radius of 900 meters, and obtain all the intersection points where the arc and the curve intersect, because there may be intersection points and communication between the vehicle and the target obstacle It is necessary to calculate the obstruction area of the target obstacle formed in the communication area of the vehicle between the vehicle and the tangent, and eliminate the intersection point with the obstruction area, for example, all the intersections of the arc and the curve There are 5 intersections, but 2 of them are located in the obstructing area. Therefore, to eliminate these 2 intersections, you only need to leave the remaining 3 intersections.

Further, referring to FIG. 3, step S400 further includes the following steps:

S401. Calculate the path distances from all primary intersections and all secondary intersections along the curve to the end of the message propagation;

S402: Select an intersection with the closest path distance among all primary intersections and all secondary intersections as the optimal position of the relay node.

Finally, it is necessary to select the optimal position of a relay node among all the first-order intersections and all the second-order intersections. It is understandable that the method for selecting the optimal position of the relay node in the present invention can use Euclidean distance, that is, at all the first-order intersections. The intersection with the shortest straight-line distance to the end of the message propagation from the second intersection is selected as the optimal position of the relay node, and the shortest path along the curve to the end of the message propagation can also be selected from all the first and second intersections. The intersection point is the optimal position of the relay node. In this embodiment, it is preferable to use the method with the shortest path distance from the intersection along the curve to the end of the message propagation, instead of the Euclidean distance method.

Further, referring to FIG. 4, after step S400, the following steps are further included:

S500. Select an iterative algorithm to perform iterative partitioning with the optimal position of the relay node as the center, and determine the candidate interval;

S600: Perform random contention on candidate nodes in the candidate interval, and use the candidate node that completes the contention first as a relay node.

Among them, the iterative algorithm may be an exponential iterative algorithm or a multivariate iterative algorithm. In this embodiment, the exponential iterative algorithm is preferred. The relay node can be a mobile platform with communication capabilities or a fixed platform with communication capabilities. For example, the mobile platform can be a motor vehicle or a non-motor vehicle, and it can also be a user's handheld terminal, such as a mobile phone and a tablet. The platform can be a base station, because the signal transmission delay of the base station is small, and it is more convenient as a relay node. In this embodiment, the relay node is preferably a motor vehicle, because motor vehicles appear most frequently, which is more convenient as a relay node.

Step S500 mainly includes the following two steps:

The first step is to divide a circular area and three circular areas within a circular area with the optimal position of the relay node as the dot and the radius of the vehicle's communication area as the radius;

In the second step, according to the order of the distance from the dots from near to far, the candidate nodes in the circular interval and the three circular intervals are judged to broadcast blocking signals in different time slots in order to determine the candidate interval.

It is understandable that the vehicle is an information sending vehicle. First, the optimal position of the relay node is the center of the circle, and the radius of the communication area of the vehicle is taken as the radius. For example, the radius of the communication area of the vehicle is 900 meters, so the relay node is the most The radius of the circular area where the preferred position is the dot is also 900 meters. According to the exponential iteration formula

Where N _part refers to the number of partitions, k refers to the partition number, W _seg (k) refers to the width of the k-th interval, for example, W _seg (1) is the radius of the first partition, and A is the compression factor; the circle The area is divided into four circles with different radii. The smallest circular interval is the first interval, and the second smallest circle is the second interval after the smallest circle is cut, and the third smallest circle The remaining annular area after the second smallest circle is cut out is the third interval, and the remaining annular area after the third smallest circle is cut out by the largest circle is the fourth interval, where the fourth interval is the maximum interval of the iteration partition. Then, according to the tangent point between the tangent and the target obstacle, the obstructed area and non-obstructed area occupied by the target obstacle in each section are calculated. After the non-obstructed area is determined, the vehicle will broadcast RTB packets to its communication area. After the candidate node receives the RTB packet, it will judge its own interval based on the GPS signal. At the same time, the candidate node in the first interval broadcasts the black-burst in the first time slot, and the candidate nodes and vehicle nodes in other intervals listen in this time slot. Channel, if there is a black-burst, the candidate nodes in other intervals quit the competition and the vehicle node selects this interval as the candidate interval. If there is no black-burst, the candidate nodes in the second interval broadcast the black-burst in the second time slot. Candidate nodes and vehicle nodes in other intervals listen to the channel in this time slot, and so on, until the candidate interval is selected. It is understandable that in a curve, only nodes located between the vehicle and the end of the message can be used as candidate nodes. There is no node between the vehicle and the end point of the message dissemination, which is meaningless to the vehicle. The iterative partition may also be divided into five intervals or six intervals, and this embodiment preferably divides into four intervals.

In step S600, after the candidate interval is selected, random contention is performed on all candidate nodes in the candidate interval, and the candidate node that completes the contention first serves as a relay node. In this embodiment, random contention is to set a backoff window, in which there are timers of different durations. The candidate nodes that have conflicting contention participate in the countdown of the timer, and the candidate node that has completed the countdown first sends the CTB packet to For vehicles, the candidate node serves as a relay node.

With reference to Figures 5 and 6, the present invention will be further described. As shown in Figure 5, there is a vehicle S2 in a curve, and the vehicle S2 is an information sending vehicle. The circular area is the communication area of the vehicle S2. For example, the radius of the communication area is 900 meters. , There is a target obstacle W2 in the communication area. The target obstacle W2 parameter is obtained through the vehicle’s own GIS system. The target obstacle W2 parameter contains the relevant information of the obstacle boundary. Take the vehicle S2 as the starting point to move towards the obstacle boundary. Two tangent lines have two tangent points, namely the first tangent point x and the second tangent point y. The first intersection point where the two tangent lines intersect the curve has an intersection point B2; the communication area boundary of the vehicle S2 intersects the curve at the second intersection point. The secondary intersections include intersection A2, intersection B2, intersection C2, and intersection D2. Among them, intersection B2 is a primary intersection and also a secondary intersection. The obstruction area is calculated through the vehicle S2 and the tangent. Obviously, intersection C2 and intersection D2 are obstructing In the area, the intersection point C2 and the intersection point D2 are eliminated, and the second intersection point leaves the intersection point A2 and the intersection point B2. Calculate the path distances from intersection A2 and intersection B2 along the curve to the message propagation destination E2. Obviously, intersection B2 is more suitable as the optimal position of the relay node than intersection A2, and finally select intersection B2 as the optimal position of the relay node.

As shown in Figure 6, firstly, the optimal position of the relay node B2 is used as the center and the exponential iterative algorithm is used to iteratively partition. The circular area is divided into four circles with different radii, and the smallest circular interval is the first interval. , The second-smallest circle cuts off the smallest circle and the remaining annular area is the second zone, the third smallest circle cuts off the second-smallest circle and the remaining annular area is the third zone, and the largest circle is cut off The remaining annular area after the third smallest circle is the fourth section. Secondly, calculate the obstacle area S=S _S2B2N -S _{S2xy of the} obstacle target obstacle based on the two tangent points of the x point and the y point, and calculate the intersection of each interval and the obstacle area, and then calculate the unobstructed area of each interval area. Then, the candidate interval is calculated, and the vehicle S2 will broadcast the RTB packet to its communication area. After the candidate node in each interval receives the RTB packet, it will judge its own interval based on the GPS signal. For example, the node V21 judges itself in the third In the section, the node V23 judges itself to be in the third section, and the node V22 in the second section is not in the communication area of the vehicle S2. At this time, the candidate nodes in the third interval include node V21 and node V23 broadcasting black-burst in the third time slot. Candidate nodes in other intervals and vehicle S2 listen to the channel in this time slot; as shown in Figure 6, the third is finally selected. The interval is used as a candidate interval, and the candidate nodes in the third interval are randomly contested. Since the node V23 is blocked by the target obstacle W2, the node V21 is selected as the relay node finally.

Referring to Figures 7 and 8, another embodiment of the present invention provides a reference comparison between the relay node selection result of the prior art method and the relay node selection result of the technical method of the present invention, where Figure 7 is the prior art The method's relay node selection result.

As shown in Figure 7, the vehicle S1 is the information sending vehicle, and E1 is the message transmission destination. In this embodiment, the communication area of the vehicle S1 is a 900-meter circle. First, obtain the intersection point between the communication area of the vehicle S1 and the curve. , There are 4 intersections, and the path distance from intersection D1 along the curve to the message propagation destination E1 is the shortest. Therefore, intersection D1 is selected as the optimal position of the relay node; then the relay node is selected according to the intersection D1, and the relay node is the most The optimal position D1 is the center of the circle. According to the exponential iterative method, three circles with a radius of less than 900 meters are made from the inside out. The smallest circle is the first interval, and the second smallest circle is the sector area left after the smallest circle is cut. The second interval is the second interval, the third interval is the third interval, and the third interval is the third interval. The communication range of the optimal position of the relay node D1 is the remaining area after the third interval is eliminated. It is the fourth interval; then it is to determine the interval where the relay node is located, and the vehicle S1 broadcasts RTB packets to its communication range. The vehicle receiving the broadcast is required to determine its own interval based on the GPS location information. The vehicle in the first interval is in the first interval. One time slot broadcasts black-burst. Vehicle nodes in other intervals and vehicle S1 listen to the channel in this time slot. If there is a black-burst, vehicle nodes in other intervals quit the competition and vehicle S1 selects this interval as the interval where the relay node is located. If there is no black-burst, the vehicle in the second interval broadcasts the black-burst in the second time slot, and the vehicle nodes and vehicles S1 in other intervals listen to the channel in this time slot, and so on. Finally, the relay node is randomly selected according to the interval where the relay node is determined. In this part, the random contention method is adopted. The vehicle node that completes the contention first can be selected as the relay node. Due to the obstacle of the target obstacle W1, among the candidate vehicle nodes V11 to V16, the candidate vehicle node V16 in the first interval cannot receive the RTB (request communication) packet broadcast from the vehicle S1, so it does not participate in accordance with the request of the RTB packet In the iterative partition relay node selection process, V11～V12 are not in the interval, so the candidate node is reduced to V13～V15, so black-burst needs to be broadcast in the fourth time slot, so the partition is time-consuming, and because of the The four sections are located in the outermost circle and occupy the largest area compared to other sections, as shown in Figure 7. Obviously, there are only 4 candidate vehicle nodes in the four sections of the optimal position of the relay node D1, and the fourth section There are 3 candidate vehicle nodes in the interval, and candidate vehicle nodes V13～V15 will participate in random contention, and the resulting random contention delay is relatively large.

As shown in Figure 8, the vehicle S1 is the information sending vehicle and E1 is the message transmission destination. In this embodiment, the communication area of the vehicle S1 is a 900-meter circle. First, the first intersection point where the tangent and the curve intersect is obtained. There is obviously only the intersection point C1 in the figure. , And then obtain the second intersection point where the communication area of the vehicle S1 intersects the curve. There are 4 intersection points. Among the four intersection points and intersection point C1, the intersection point C1 has the shortest path distance along the curve to the message propagation end point E1, and the intersection point C1 is also It is not in the obstacle area of the target obstacle W1, so the intersection C1 is selected as the optimal position of the relay node, and then the optimal position of the relay node C1 is used as the center to perform iterative partitioning. The partitioning process is the same as the above. After partitioning, there are candidates The relay nodes V11 to V16, among which the candidate relay nodes V14 and V15 are in the second interval, and the relay nodes are preferentially selected from the candidate relay nodes V14 and V15, so the random contention delay is relatively small.

To sum up, this method first obtains the obstacle parameters in the communication area of the vehicle, and then draws the tangent line between the vehicle and the obstacle boundary, and obtains all the first intersection points of the tangent line and the curve, and then calculates the vehicle communication area boundary and The curve intersects all the secondary intersections that are not blocked by the target obstacle, and finally selects an intersection from all primary intersections and all secondary intersections as the optimal position of the relay node. The communication between the optimal position of the relay node selected by the method of the prior art and the vehicle may be hindered by the target obstacle, resulting in greater random contention when the relay node is selected subsequently through the optimal position of the relay node Delay; and the communication between the optimal position of the relay node selected by the method of the present invention and the vehicle will not be hindered by the target obstacle, so that the process of selecting the relay node iteratively takes the optimal position of the relay node as the center , Can reduce the partition time and avoid greater random contention delay. This method can effectively reduce the overall delay of broadcast relay node selection when obstacles affect signal propagation in the scene of the car network curve.

Referring to FIG. 9, another embodiment of the present invention provides a device for selecting an optimal position of a relay node applied to a curve scene of a car network, including the following units: an obstacle parameter receiving unit 100, a first-intersection point acquiring unit 200 , The secondary intersection point obtaining unit 300 and the relay node optimal position selecting unit 400;

The obstacle parameter receiving unit 100 is used to obtain the obstacle parameter of the target obstacle in the communication area of the vehicle;

The primary intersection acquisition unit 200 is configured to calculate the tangent between the vehicle and the boundary of the obstacle according to the obstacle parameters, and acquire all primary intersections where the tangent and the curve intersect in the communication area of the vehicle;

The secondary intersection acquiring unit 300 is configured to acquire all secondary intersections where the boundary of the communication area of the vehicle intersects the curve and is not obstructed by the target obstacle;

The optimal position selection unit 400 of the relay node is used to select the optimal position of the relay node from all the first-order intersection points and all the second-order intersection points.

Further, it also includes the following units: a candidate interval selection unit and a relay node selection unit;

The candidate interval selection unit is used to select an iterative algorithm for iterative partitioning with the optimal position of the relay node as the center, and determine the candidate interval;

The relay node selection unit is used for random contention for candidate nodes in the candidate interval, and the candidate node that completes the contention first is used as the relay node.

Referring to FIG. 10, another embodiment of the present invention provides a device for selecting the optimal position of a relay node applied to a car network curve scene, including at least one control processor and used for communicating with at least one control processor Connected memory; the memory stores instructions that can be executed by at least one control processor, and the instructions are executed by at least one control processor, so that the optimal position of the relay node of the above-mentioned embodiment is applied to the vehicle network curve scene The selection method, for example, executes the method steps S100 to S400 in FIG. 1, the method steps S301 to S302 in FIG. 2, the method steps S401 to S402 in FIG. 3, and the method steps S500 to S600 in FIG. 4 described above.

Further, another embodiment of the present invention also provides a computer-readable storage medium. The computer-readable storage medium stores computer-executable instructions. The computer-executable instructions are used to make a computer execute an application of the above-mentioned embodiments. The method for selecting the optimal position of the relay node in the car network curve scene, for example, executes the method steps S100 to S400 in FIG. 1, the method steps S301 to S302 in FIG. 2, and the method steps S401 to S401 to in FIG. S402 and the method steps S500 to S600 in FIG. 4.

Through the description of the above implementation manners, those skilled in the art can clearly understand that each implementation manner can be implemented by means of software plus a general hardware platform. Those skilled in the art can understand that all or part of the processes in the methods of the foregoing embodiments can be implemented by a computer program instructing relevant hardware. The program can be stored in a computer readable storage medium. When the program is executed, it can include As the flow of the embodiment of the above method. Among them, the storage medium may be a magnetic disk, an optical disc, a read-only memory (Read Only Memory, ROM), or a random access memory (Random Access Memory, RAM).

The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the above-mentioned embodiments. Various changes can be made without departing from the purpose of the present invention within the scope of knowledge possessed by those of ordinary skill in the technical field. .

Claims

A method for selecting the optimal position of a relay node applied to a curve scene of a car network is characterized in that it includes the following steps:

Obtain the obstacle parameters of the target obstacle in the communication area of the vehicle;

Calculate a tangent line between the vehicle and the boundary of the obstacle according to the obstacle parameter, and obtain all the first intersection points where the tangent line and the curve intersect in the communication area of the vehicle;

Acquiring all secondary intersection points where the boundary of the communication area of the vehicle intersects the curve and is not obstructed by the target obstacle;

The optimal position of the relay node is selected among all the primary intersections and all the secondary intersections.
The method for selecting the optimal position of a relay node applied to a curve scene in a connected car according to claim 1, wherein the acquiring of the communication area boundary of the vehicle and the curve is not affected by the intersection of the vehicle and the curve. All the secondary intersection points obstructed by the target obstacle also include the following steps:

Acquiring an obstruction area of the target obstacle formed between the vehicle and the tangent line;

Obtain all intersection points where the boundary of the communication area of the vehicle intersects the curve, and select all secondary intersection points that are not in the obstruction area from all the intersection points.
The method for selecting the optimal position of the relay node applied to the car network curve scene according to claim 1, characterized in that, selecting the middle point from all the first intersection points and all the second intersection points Following the optimal position of the node, the following steps are included:

Calculate the path distance from all the primary intersections and all the secondary intersections along the curve to the end of the message propagation;

Among all the primary intersections and all the secondary intersections, the intersection with the closest path distance is selected as the optimal position of the relay node.
The method for selecting the optimal position of the relay node applied to the curve scene of the Internet of Vehicles according to claim 1, characterized in that, the calculation is performed among all the primary intersections and all the secondary intersections. Following the optimal position of the node, it also includes the following steps:

Select an iterative algorithm to perform iterative partitioning with the optimal position of the relay node as the center, and determine the candidate interval;

Random contention is performed on candidate nodes in the candidate interval, and the candidate node that completes the contention first is used as a relay node.
According to claim 4, a method for selecting the optimal position of a relay node applied to a curve scene of a car network, wherein the iterative algorithm comprises an exponential iterative algorithm.
According to claim 4, a method for selecting the optimal position of a relay node applied to a curve scene in an Internet of Vehicles, wherein the relay node comprises a mobile platform with communication capabilities or a fixed platform with communication capabilities .
A device for selecting the optimal position of a relay node applied to a curve scene of a car network, which is characterized by comprising the following units: an obstacle parameter receiving unit, a primary intersection acquiring unit, a secondary intersection acquiring unit, and an optimal relay node Location selection unit;

The obstacle parameter receiving unit is used to obtain the obstacle parameter of the target obstacle in the communication area of the vehicle;

The primary intersection acquiring unit is configured to calculate the tangent between the vehicle and the boundary of the obstacle according to the obstacle parameter, and acquire all primary intersections where the tangent and the curve intersect in the communication area of the vehicle;

The secondary intersection point acquiring unit is configured to acquire all secondary intersection points where the boundary of the communication area of the vehicle and the curve intersect and are not hindered by the target obstacle;

The optimal position selection unit of the relay node is used to select the optimal position of the relay node from all the primary intersections and all the secondary intersections.
The device for selecting the optimal position of the relay node applied to the car network curve scene according to claim 7, further comprising the following units: a candidate interval selection unit and a relay node selection unit;

The candidate interval selection unit is configured to select an iterative algorithm to perform iterative partitioning with the optimal position of the relay node as the center, and determine the candidate interval;

The relay node selection unit is used to randomly compete for candidate nodes in the candidate interval, and use the candidate node that completes the contention first as the relay node.
A device for selecting the optimal position of a relay node applied to a curve scene of a car network, characterized in that it includes at least one control processor and a memory for communicating with the at least one control processor; the memory stores There are instructions that can be executed by the at least one control processor, and the instructions are executed by the at least one control processor to enable the at least one control processor to execute any one of claims 1 to 6 A method for selecting the optimal position of a relay node applied to a curve scene of a car network.
A computer-readable storage medium, characterized in that: the computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are used to make a computer execute any one of claims 1-6. A method for selecting the optimal position of a relay node applied to a curve scene in a car network.