CN109257792B - Intersection universal relay node selection method applied to Internet of vehicles - Google Patents
Intersection universal relay node selection method applied to Internet of vehicles Download PDFInfo
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- H04W40/00—Communication routing or communication path finding
- H04W40/02—Communication route or path selection, e.g. power-based or shortest path routing
- H04W40/22—Communication route or path selection, e.g. power-based or shortest path routing using selective relaying for reaching a BTS [Base Transceiver Station] or an access point
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- H04W4/40—Services specially adapted for particular environments, situations or purposes for vehicles, e.g. vehicle-to-pedestrians [V2P]
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Abstract
The application discloses a method, a system, equipment and a medium for selecting a universal relay node of a crossroad applied to the Internet of vehicles, wherein the method comprises the steps of selecting a relay node of the crossroad and selecting a relay node of a branch road, and the selection process of any relay node comprises the following steps: when a request broadcast transmission packet sent by a vehicle node is received, determining a segmentation area; and carrying out iterative segmentation processing on the segmented region, determining all candidate nodes, and determining the relay node from the candidate nodes. The iterative segmentation processing process comprises the following steps: s11: dividing a region to be processed into region blocks with different widths according to a preset rule; s12: broadcasting a blocking signal according to a time slot corresponding to the area block where the blocking signal is located; s13: and taking the area block corresponding to the vehicle node which has sent the blocking signal as a new area to be processed, and entering S11 until the iteration number reaches a preset threshold value. The invention divides the division area into blocks with unequal widths to select the relay nodes, and finally reduces the candidate nodes for determining the relay nodes, thereby reducing the selection time delay and the conflict.
Description
Technical Field
The invention relates to the technical field of vehicle networking, in particular to a method, a system, equipment and a storage medium for selecting a universal relay node at an intersection, which are applied to the vehicle networking.
Background
As is well known, the ability of establishing direct communication between vehicles can realize information sharing between vehicles, so that a driver can be warned or automatically intervened and intervened in the operation of the vehicles before an accident occurs, the occurrence of the accident is effectively avoided or the harm caused by the accident is reduced, meanwhile, the efficiency of a traffic system is improved, the energy consumption and the pollutant emission are reduced, and the intelligent traffic system is a basic technology of intelligent traffic. The direct vehicle-to-vehicle communication has the advantages of small transmission delay, discovery of neighboring vehicles, and economic benefits of low investment and low maintenance costs due to its ad hoc nature, relative to vehicle-to-vehicle communication established over cellular networks.
Since the communication range of a single vehicle is limited, the communication is relayed by the vehicle, and the message coverage area can be increased. The conventional relay node selection method applied to the intersection can obtain the neighbor node information by exchanging beacons. However, because of the large number of vehicles, the beacon period interval cannot be too small, generally 100ms, to avoid the channel load being too large. However, this results in poor real-time performance of the location information and increased load in the communication network with a high vehicle density. Another type of relay node selection method applied to the intersection does not need prior information of vehicles, namely beacon exchange node information is not needed, and only a blocking signal is used for selecting the optimal relay node, so that a faster message propagation speed is obtained. However, in the existing method, when the vehicle density is high or the number of vehicles in the vehicle communication range is extremely small, the message transmission speed performance is sharply reduced. In view of this, how to select a relay node in an intersection is an urgent problem to be solved to ensure that a message can be transmitted to a target node or an interested area covering the message as quickly and reliably as possible.
Disclosure of Invention
In view of the above, the present invention aims to provide a vehicle communication method, system, device and storage medium. The specific scheme is as follows:
in a first aspect, the invention discloses a method for selecting a universal relay node for an intersection applied to a vehicle networking, which is applied to candidate vehicle nodes in an intersection area, wherein the intersection area is an area corresponding to a circle which takes an intersection center position as a circle center and takes a half of a vehicle communication distance as a radius, and the method comprises the following steps:
when a request broadcast propagation packet sent by a vehicle node is received, determining an intersection segmentation area; the request broadcast propagation packet is specifically a request broadcast propagation packet which is sent to all the candidate vehicle nodes in the intersection area when the vehicle node reaches the intersection area, and the intersection partition area is an area corresponding to a circle which takes the intersection center position as the center of the circle and takes the distance from the vehicle node to the intersection center position as the radius;
taking the intersection partition area as an area to be processed for iterative partition processing, determining all candidate relay nodes so that the vehicle node can determine an intersection relay node from all the candidate relay nodes, determining a branch relay node on a branch through the intersection relay node, and completing selection of the intersection relay node;
the process of performing iterative segmentation processing on any region to be processed comprises the following steps:
s11: dividing the region to be processed into region blocks with different widths according to a preset rule;
s12: broadcasting a blocking signal according to a time slot corresponding to the area block where the blocking signal is located;
s13: and taking the area block corresponding to the vehicle node which has sent the blocking signal as a new area to be processed, and entering S11 until the iteration number reaches a preset threshold value.
Optionally, the S11 includes:
dividing the region to be processed into region blocks with unequal widths according to a preset segmentation formula; wherein the preset segmentation formula is as follows:
wherein A is a compression coefficient, NpartIs the total number of region blocks, Wseg(k) The width of the kth region block.
Optionally, before broadcasting the blocking signal according to the timeslot corresponding to the area block where the blocking signal is located, the method further includes:
judging whether blocking signals sent by other candidate vehicle nodes are intercepted or not;
if so, the blocking signal is no longer transmitted.
Optionally, the determining an intersection relay node from all the candidate relay nodes includes:
and determining the intersection relay node from all the candidate relay nodes in a random selection mode.
Optionally, the determining, by the intersection relay node, a branch relay node on a branch to complete selection of the intersection relay node includes:
the intersection relay node sends a request broadcast propagation packet to all target vehicle nodes on a branch road so that the target vehicle nodes can determine a branch road segmentation area corresponding to the current branch road, and the branch road segmentation area is used as the area to be processed to perform iterative segmentation processing to determine all branch road vehicle candidate nodes;
and the intersection relay node determines branch relay nodes from all the branch vehicle candidate nodes to complete the selection of the intersection relay nodes.
Optionally, the determining the branch dividing region corresponding to the current branch includes:
judging whether the intersection relay node is positioned in the current branch or not;
if so, the branch division region corresponding to the current branch is a region in which the distance between the current branch and the intersection relay node along the message propagation direction is less than the vehicle communication distance;
if not, the branch dividing region corresponding to the current branch is a region corresponding to the optimal position of the current branch from the center position of the intersection in the current branch; and the optimal position is the position which is farthest from the center position of the intersection in the coverage area of the communication area of the intersection relay node on the current branch.
In a second aspect, the present invention discloses a system for selecting a universal relay node for an intersection in a vehicle networking, which is applied to candidate vehicle nodes in an intersection area, wherein the intersection area is an area corresponding to a circle which takes an intersection center position as a circle center and takes a half of a vehicle communication distance as a radius, and the system comprises:
the region determining module is used for determining intersection segmentation regions when a request broadcast propagation packet sent by a vehicle node is received; the request broadcast propagation packet is specifically a request broadcast propagation packet which is sent to all the candidate vehicle nodes in the intersection area when the vehicle node reaches the intersection area, and the intersection partition area is an area corresponding to a circle which takes the intersection center position as the center of the circle and takes the distance from the vehicle node to the intersection center position as the radius;
the relay node determination module is used for taking the intersection segmentation area as an area to be processed, performing iterative segmentation processing by using an iterative processing submodule, and determining all candidate relay nodes so that the vehicle node can determine the intersection relay node from all the candidate relay nodes, and determining a branch relay node on a branch through the intersection relay node to finish the selection of the intersection relay node;
wherein the iterative processing submodule comprises:
the dividing unit is used for dividing the region to be processed into region blocks with different widths according to a preset rule;
the broadcasting unit is used for broadcasting the blocking signal according to the time slot corresponding to the area block where the broadcasting unit is located;
and the determining unit is used for taking the area block corresponding to the vehicle node which has sent the blocking signal as a new area to be processed and starting the working process of the dividing unit until the iteration number reaches a preset threshold value.
Optionally, the iterative processing sub-module further includes:
the judging unit is used for judging whether the blocking signals sent by other candidate vehicle nodes are intercepted or not before the blocking signals are broadcasted according to the time slots corresponding to the area blocks where the judging unit is located; if so, the blocking signal is no longer transmitted.
In a third aspect, the present invention discloses an electronic device, comprising:
a memory for storing a computer program;
and the processor is used for realizing the method for selecting the universal relay node of the intersection applied to the Internet of vehicles when executing the computer program.
In a fourth aspect, the present invention discloses a computer readable medium for storing a computer program which, when executed by a processor, implements the aforementioned disclosed method for selecting a universal relay node for an intersection in a vehicle networking application.
Therefore, when a request broadcast propagation packet sent by a vehicle node is received, the intersection segmentation area is determined; the request broadcast propagation packet is specifically a request broadcast propagation packet which is sent to all the candidate vehicle nodes in the intersection area when the vehicle node reaches the intersection area, and the intersection partition area is an area corresponding to a circle which takes the intersection center position as the center of the circle and takes the distance from the vehicle node to the intersection center position as the radius; taking the intersection partition area as an area to be processed for iterative partition processing, determining all candidate relay nodes so that the vehicle node can determine an intersection relay node from all the candidate relay nodes, determining a branch relay node on a branch through the intersection relay node, and completing selection of the intersection relay node; the process of performing iterative segmentation processing on any region to be processed comprises the following steps: s11: dividing the region to be processed into region blocks with different widths according to a preset rule; s12: broadcasting a blocking signal according to a time slot corresponding to the area block where the blocking signal is located; s13: and taking the area block corresponding to the vehicle node which has sent the blocking signal as a new area to be processed, and entering S11 until the iteration number reaches a preset threshold value. That is, the invention selects the relay node by dividing the intersection partition area into blocks with unequal widths, so that the block width closer to the optimal position is smaller, candidate nodes are reduced when the relay node is finally determined, and the selection delay and conflict are reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 is a flowchart of a specific implementation of a method for selecting a universal relay node at an intersection in an internet of vehicles according to an embodiment of the present invention;
fig. 2 is a flowchart of an iterative segmentation processing procedure in a specific implementation of a method for selecting a universal relay node for an intersection in the internet of vehicles according to an embodiment of the present invention;
fig. 3 is a schematic diagram of an iterative segmentation processing procedure in a specific implementation of a method for selecting a universal relay node for an intersection in the internet of vehicles according to an embodiment of the present invention;
fig. 4 is a flowchart illustrating a process in which an intersection relay node sends a message to a branch vehicle node in a specific embodiment of a method for selecting a universal relay node for an intersection in the internet of vehicles according to an embodiment of the present invention;
fig. 5 is a schematic diagram illustrating a typical intersection relay node selection in a specific embodiment of a method for selecting a universal relay node for an intersection in an internet of vehicles according to an embodiment of the present invention;
fig. 6 is a schematic process diagram of intersection iterative segmentation in a specific implementation of a method for selecting a universal relay node for an intersection in the internet of vehicles according to an embodiment of the present invention;
fig. 7 is a schematic process diagram of branch iteration segmentation in a specific implementation of a method for selecting a universal relay node at an intersection in the internet of vehicles according to an embodiment of the present invention;
FIG. 8 is a graph comparing message transmission speed of the method for selecting a universal relay node for an intersection in a vehicle networking system according to an embodiment of the present invention in a simulation system with that of a prior art method;
fig. 9 is a graph comparing packet delivery rates of the method for selecting a universal relay node for an intersection in the internet of vehicles according to the embodiment of the present invention in a simulation system with that of the prior art;
fig. 10 is a block diagram of a system for selecting a universal relay node at an intersection in a vehicle networking system according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The traditional relay node selection method applied to the intersection can obtain the adjacent node information by exchanging beacons, but the method causes poor real-time performance of position information and increased load in a communication network with high vehicle density. Another type of relay node selection method applied to intersections selects an optimal relay node only by means of a blocking signal, so as to obtain a faster message propagation speed, but such a method has the problem that when the vehicle density is high or the number of vehicles in the vehicle communication range is very small, the message transmission speed performance is drastically reduced.
The embodiment of the invention discloses a method for selecting a universal relay node of an intersection applied to a vehicle networking, which is applied to candidate vehicle nodes in an intersection area, wherein the intersection area is an area corresponding to a circle which takes the center position of the intersection as the center of the circle and takes a half of the vehicle communication distance as the radius, and the method is shown in figure 1 and comprises the following steps:
step S101: when a request broadcast propagation packet sent by a vehicle node is received, determining an intersection segmentation area; the request broadcast propagation packet is specifically a request broadcast propagation packet which is sent to all the candidate vehicle nodes in the intersection area when the vehicle node reaches the intersection area, and the intersection partition area is an area corresponding to a circle which takes the intersection center position as the center of the circle and takes the distance from the vehicle node to the intersection center position as the radius;
in this embodiment, when the vehicle node reaches the intersection region, the selection of the intersection relay node is started, that is, the vehicle node closest to the optimal position is found as the relay node of the intersection, and the optimal position is the intersection center position.
Specifically, after the vehicle node adopts a Mini-DIFS strategy to access the channel, an RTB (request broadcast packet) is sent to all target vehicle nodes in the communication range of the vehicle node to inform the target vehicle nodes of the start of relay node selection. The RTB packet comprises position information, communication range information and iteration segmentation starting time of the vehicle node.
It can be understood that the intersection region is a region corresponding to a circle having the center position of the intersection as the center of the circle and a half of the vehicle communication distance as the radius, and the intersection dividing region is a portion for further dividing the intersection region to find the relay node. In the embodiment of the invention, in order to find the vehicle node closer to the center of the intersection than the vehicle node as the relay node, the intersection segmentation area is not a circle taking the vehicle communication distance as the diameter in the traditional method, but an area corresponding to the circle taking the center position of the intersection as the center of the circle and the distance from the vehicle node to the center position of the intersection as the radius.
Step S102: taking the intersection partition area as an area to be processed for iterative partition processing, determining all candidate relay nodes so that the vehicle node can determine an intersection relay node from all the candidate relay nodes, determining a branch relay node on a branch through the intersection relay node, and completing selection of the intersection relay node;
it can be understood that, in this embodiment, the intersection division region is subjected to an iterative division process, so as to determine all candidate relay nodes. Wherein the candidate relay nodes are all vehicle nodes in a non-empty final area closest to the optimal position.
In this embodiment, the intersection relay node is determined from all the candidate relay nodes in a random selection manner. Specifically, in this embodiment, a backoff clock is randomly selected for all candidate relay nodes, and the candidate node that finishes backoff first is used as the intersection relay node. And finally, the vehicle which successfully becomes the intersection relay node sends a CTB (clear broadcast propagation packet) to inform the vehicle node which sends the message, the handshake is completed, and the intersection relay node selection process is finished.
Further, the intersection relay node is used for determining the branch relay node on the branch, and the selection of the intersection stage and the branch stage relay node is completed.
Referring to fig. 2, the process of performing the iterative segmentation processing on any one of the regions to be processed in this embodiment includes:
s11: dividing the region to be processed into region blocks with different widths according to a preset rule;
in this embodiment, the region to be processed is divided into region blocks with different widths according to a preset rule. Compared with the traditional intersection relay node selection method in which the width of the partitioned area blocks is not changed, the partition method of the embodiment adopts partition with unequal block widths for the partitioned area, the block width closer to the optimal position is smaller, so that the number of nodes in the area block closest to the optimal position, which is finally determined, is reduced, and the selection time delay is reduced.
S12: broadcasting a blocking signal according to a time slot corresponding to the area block where the blocking signal is located;
in this embodiment, after receiving the RTB packet, the candidate relay node determines the area block where the candidate relay node is located, and broadcasts a blocking signal according to the time slot corresponding to the located area block, that is, the vehicle node in the area block closest to the optimal position sends the blocking signal earliest.
Specifically, if the candidate relay node monitors the blocking signals sent by other candidate relay nodes before broadcasting the blocking signals according to the time slot corresponding to the located area block, it indicates that there is a vehicle node closer to the optimal position, and the current candidate relay node will not send the blocking signals, so as to quit the relay node selection process.
S13: and taking the area block corresponding to the vehicle node which has sent the blocking signal as a new area to be processed, and entering S11 until the iteration number reaches a preset threshold value.
Further, in this embodiment, the area block corresponding to the vehicle node that has sent the blocking signal is used as a new area to be processed, and the area block where the vehicle node that has sent the blocking signal is located is the area closest to the optimal position at present. And further carrying out iterative segmentation on the new region to be processed until the iteration times reach a preset threshold value, and determining a non-empty region closest to the optimal position as a final region block. Accordingly, intersection relay nodes are determined from all candidate relay nodes in the final block.
In this embodiment, in order to save time, in each iteration division, if only a vehicle node exists in the last area block, that is, a node exists in an area farthest from the optimal position, the vehicle node in the area block directly enters the next iteration process without sending a blocking signal. If the iteration number reaches a preset threshold value, the vehicle node in the area block directly selects a backoff clock and enters a relay node competition stage. The preset threshold may be customized in a specific implementation process, and is not limited herein.
It can be understood that the embodiment of the invention can be applied to relay node selection of intersections with a plurality of branches and any included angle between the branches, realizes vehicle communication including the intersections with the plurality of branches, is not only suitable for typical intersection scenes, and has universality.
Therefore, when a request broadcast propagation packet sent by a vehicle node is received, the intersection segmentation area is determined; the request broadcast propagation packet is specifically a request broadcast propagation packet which is sent to all the candidate vehicle nodes in the intersection area when the vehicle node reaches the intersection area, and the intersection partition area is an area corresponding to a circle which takes the intersection center position as the center of the circle and takes the distance from the vehicle node to the intersection center position as the radius; taking the intersection partition area as an area to be processed for iterative partition processing, determining all candidate relay nodes so that the vehicle node can determine an intersection relay node from all the candidate relay nodes, determining a branch relay node on a branch through the intersection relay node, and completing selection of the intersection relay node; the process of performing iterative segmentation processing on any region to be processed comprises the following steps: s11: dividing the region to be processed into region blocks with different widths according to a preset rule; s12: broadcasting a blocking signal according to a time slot corresponding to the area block where the blocking signal is located; s13: and taking the area block corresponding to the vehicle node which has sent the blocking signal as a new area to be processed, and entering S11 until the iteration number reaches a preset threshold value. That is, the invention selects the relay node by dividing the intersection partition area into blocks with unequal widths, so that the block width closer to the optimal position is smaller, candidate nodes are reduced when the relay node is finally determined, and the selection delay and conflict are reduced.
In another specific embodiment of the method for selecting a universal relay node for an intersection in the internet of vehicles provided by the present invention, a process for dividing the region to be processed into unequal-width regions according to a preset rule is further described, where the process specifically includes:
dividing the region to be processed into region blocks with unequal widths according to a preset segmentation formula; wherein the preset segmentation formula is as follows:
wherein A is a compression coefficient, NpartIs the total number of region blocks, Wseg(k) The width of the kth region block.
Referring to FIG. 3, FIG. 3 illustrates the transition through NiterSecond iteration of dividing NpartAnd (5) an iterative segmentation process of each area block. In the first iteration, the farthest non-empty block is the ith block, and the vehicle in the ith block transmits a block signal in the ith time slot. Vehicles in other blocks of the area sense the blocking signal and exit the relay node selection. In the second iteration, the farthest non-empty region block is the NthpartAnd (4) each area block, wherein the nodes in the area block do not send blocking signals and directly enter the third iterative segmentation. This iterative division up to NiterThe secondary iteration is completed.
In another specific embodiment of the method for selecting a universal relay node for an intersection in a vehicle networking system according to the present invention, a process for determining a branch relay node on a branch through the intersection relay node is further described, and as shown in fig. 4, the process specifically includes:
step S201: the intersection relay node sends a request broadcast propagation packet to all target vehicle nodes on a branch road so that the target vehicle nodes can determine a branch road segmentation area corresponding to the current branch road, and the branch road segmentation area is used as the area to be processed to perform iterative segmentation processing to determine all branch road vehicle candidate nodes;
in this embodiment, the determined intersection relay node sends a request broadcast propagation packet to all target vehicle nodes on the branch, and further determines a branch segmentation area corresponding to the current branch. Specifically, the process of determining the branch segmentation area corresponding to the current branch in this embodiment is as follows: judging whether the intersection relay node is positioned in the current branch or not; if so, the branch division region corresponding to the current branch is a region in which the distance between the current branch and the intersection relay node along the message propagation direction is less than the vehicle communication distance; if not, the branch dividing region corresponding to the current branch is a region corresponding to the optimal position of the current branch from the center position of the intersection in the current branch; and the optimal position is the position which is farthest from the center position of the intersection in the coverage area of the communication area of the intersection relay node on the current branch.
In this embodiment, the iterative segmentation processing process may refer to the disclosure of the foregoing embodiment, and is not described herein again.
Step S202: and the intersection relay node determines branch relay nodes from all the branch vehicle candidate nodes to complete the selection of the intersection relay nodes.
In this embodiment, the branch relay nodes are determined in a random selection manner from all the branch vehicle candidate nodes, wherein specific processes of the random selection manner may refer to the disclosure of the foregoing embodiments, and are not described herein again.
Further, the present invention is explained by taking the typical intersection depicted in fig. 5 as an example, specifically: the message is propagated from the west to the branch, and the H selected as the relay node finds itself in the intersection area, and takes on the task of searching the intersection relay node to become a hunting node for sending the message.
In the intersection stage, the intersection division area is an area covered by a circle with the center position C of the intersection as the center of the circle and the distance from H to C as the radius, and the area is the area of the intersection stage (the area covered by the circle drawn by the corresponding virtual point). All vehicles in the communication range of the hunting node H can receive the RTB packet sent by the node H, further determine the range of the divided region, and calculate the distance between the vehicles and the node C according to the positioning information of the vehicles and the GIS information system. Each node enters iterative segmentation, and the block where the node is located is judged according to a preset segmentation formula. As shown in particular in fig. 6.
For the first iteration segmentation, the segmentation area is divided into three areas, namely a circle 5, a circle 4 and a circle 1, the length of the branch covered by the circle 1 is the shortest, and the length of the branch covered by the annular area encircled by the circle 5 and the circle 4 is the longest. Because no vehicle node exists in the area covered by the circle 1, the vehicle nodes in the annular areas defined by the circles 1 and 4 transmit the blocking signal in the 2 nd time slot, after the vehicle nodes in the annular areas defined by the circles 5 and 4 sense the blocking signal, the relay node selection is exited, and after the transmission of the blocking signal is finished, all the vehicle nodes which transmit the blocking signal, namely the vehicle nodes in the annular areas defined by the circles 1 and 4 enter the second iteration division. The annular area enclosed by circles 1, 4 is divided into 3 areas by circles 2, 3. Similarly, the diameter of the circle defined by the circle 1 and the circle 2 is the smallest, and the diameter of the circle defined by the circle 3 and the circle 4 is the largest. Because there is no vehicle node in two rings defined by circles 1 and 2 and circles 2 and 3, and there is a node only in the outermost ring segmented by this iteration, after 2 time slots, 3 vehicles in the fixed rings defined by circles 3 and 4 compete to realize the selection of the relay node through CTB (clear broadcast transmission packet), and finally, the vehicle R on the east branchIBecoming intersection relay nodes.
In the branch phase, when the vehicle R is shown in FIG. 7IThe relay node selected as the intersection is responsible for sending the message packet to the other three legs (north, south and east) than the message coming leg (west leg). The selected optimal positions (positions on the branch road farthest from the center of the intersection in the communication range of the intersection relay nodes) on the 3 branches are respectively marked as Popt_N,Popt_SAnd Popt_E. Because the intersection relay node RIOn the east branch, the division area of the east branch is RITo Popt_EAnd the other 2 branches are C to the area of the optimal position. Vehicle node RIAnd after accessing the channel, sending an RTB packet to all vehicle nodes in the communication range of the RTB packet, and informing the branch relay nodes of starting to select. The RTB packet contains RIPosition information, and branch resistancesThe frequency to which the plug signal corresponds. Each branch starts the selection of the relay node at the same time, because the blocking signals with different frequencies are adopted, the interference between the blocking signals is avoided. Taking the iterative division of the east branch as an example, the process of selecting the branch relay node is described. RITo Popt_EIs non-uniformly divided into 3 blocks, the 1 st block has the smallest width, and the 3 rd block has the largest width. Since there are vehicle nodes in block 1, in the first time slot, the vehicle nodes in block 1 broadcast blocking signals informing the vehicles in blocks 2 and 3 to exit the relay node selection. At the end of slot 1, the vehicles in block 1 enter the 2 nd iterative partition. In the 2 nd iteration division, no vehicle exists in the 1 st and 2 nd area blocks, so the vehicle in the 3 rd area block directly enters the CTB competition stage in the 3 rd time slot after the 2 nd time slot is finished and no blocking signal is sensed. Finally, the vehicle RB_EThe relay node selected as the east branch.
Further, in this embodiment, the MATLAB is used to simulate the intersection, and the performance of the method of the present invention is detected. Specifically, a crossroad simulation environment is established in the MATLAB, and VANET communication parameters are adopted. The communication transmission range of the vehicle is set to 400 meters, and the length of each branch of the intersection is 700 meters. The vehicles are distributed on four branches. And fixing the hunting node H at a position of the west-oriented branch 200 meters away from the center of the intersection, wherein the obtained performance is the lower bound value of the performance of all the situations. In order to measure the performance improvement of the relay node selection method, the AMB and BPAB methods in the crossroad scene are simulated. (N) of the method and BPAB of the inventioniter,Npart) Set to (2,4) and (4,2), respectively, (N) was also simulated for comparison of gains due to exponential segmentationiter,Npart) An iterative segmentation method with equal block widths of (2, 4). Fig. 8 and 9 show the message transmission speed and packet delivery rate PDR of the 4 methods, respectively. From experimental results, it can be seen that the method of the present invention achieves the fastest message transmission speed.
Further, the present invention discloses a system for selecting a universal relay node for an intersection in a vehicle networking, which is applied to candidate vehicle nodes in an intersection area, where the intersection area is an area corresponding to a circle having an intersection center position as a circle center and a half of a vehicle communication distance as a radius, and as shown in fig. 10, the vehicle communication system includes:
the region determining module 100 is configured to determine an intersection segmentation region when receiving a request broadcast propagation packet sent by a vehicle node; the request broadcast propagation packet is specifically a request broadcast propagation packet which is sent to all the candidate vehicle nodes in the intersection area when the vehicle node reaches the intersection area, and the intersection partition area is an area corresponding to a circle which takes the intersection center position as the center of the circle and takes the distance from the vehicle node to the intersection center position as the radius;
the relay node determination module 200 is configured to perform iterative segmentation processing on the intersection segmentation region serving as a region to be processed by using an iterative processing submodule, and determine all candidate relay nodes, so that the vehicle node determines an intersection relay node from all the candidate relay nodes, and determines a branch relay node on a branch through the intersection relay node, thereby completing selection of an intersection relay node;
wherein the iterative processing submodule comprises:
the dividing unit is used for dividing the region to be processed into region blocks with different widths according to a preset rule;
the broadcasting unit is used for broadcasting the blocking signal according to the time slot corresponding to the area block where the broadcasting unit is located;
and the determining unit is used for taking the area block corresponding to the vehicle node which has sent the blocking signal as a new area to be processed and starting the working process of the dividing unit until the iteration number reaches a preset threshold value.
Further, the iterative processing sub-module further includes:
the judging unit is used for judging whether the blocking signals sent by other candidate vehicle nodes are intercepted or not before the blocking signals are broadcasted according to the time slots corresponding to the area blocks where the judging unit is located; if so, the blocking signal is no longer transmitted.
Further, the embodiment of the invention also discloses an electronic device, which comprises a memory and a processor, wherein the processor realizes the method for selecting the intersection universal relay node applied to the internet of vehicles when executing the computer program stored in the memory.
Further, the present invention discloses a computer readable medium for storing a computer program which, when executed by a processor, implements the aforementioned disclosed method for selecting a universal relay node for an intersection applied to a vehicle networking.
According to the invention, the intersection partition area is divided into blocks with unequal widths to select the relay nodes, so that the block width closer to the optimal position is smaller, candidate nodes are reduced when the relay nodes are finally determined, and the selection delay and conflict are reduced.
The embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same or similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.
Those of skill would further appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative components and steps have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in Random Access Memory (RAM), memory, Read Only Memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.
Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The method, the system, the equipment and the storage medium for selecting the universal relay node of the intersection applied to the internet of vehicles provided by the invention are introduced in detail, a specific example is applied in the text to explain the principle and the implementation mode of the invention, and the description of the embodiment is only used for helping to understand the method and the core idea of the invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.
Claims (10)
1. A method for selecting a universal relay node of an intersection applied to a vehicle networking is characterized by being applied to candidate vehicle nodes in an intersection area, wherein the intersection area is an area corresponding to a circle which takes an intersection center position as a circle center and takes a half of a vehicle communication distance as a radius, and the method comprises the following steps:
when a request broadcast propagation packet sent by a vehicle node is received, determining an intersection segmentation area; the request broadcast propagation packet is specifically a request broadcast propagation packet which is sent to all the candidate vehicle nodes in the intersection area when the vehicle node reaches the intersection area, and the intersection partition area is an area corresponding to a circle which takes the intersection center position as the center of the circle and takes the distance from the vehicle node to the intersection center position as the radius;
taking the intersection partition area as an area to be processed for iterative partition processing, determining all candidate relay nodes so that the vehicle node can determine an intersection relay node from all the candidate relay nodes, determining a branch relay node on a branch through the intersection relay node, and completing selection of the intersection relay node;
the process of performing iterative segmentation processing on any region to be processed comprises the following steps:
s11: dividing the region to be processed into region blocks with different widths according to a preset rule;
s12: broadcasting a blocking signal according to a time slot corresponding to the area block where the blocking signal is located;
s13: and taking the area block corresponding to the vehicle node which has sent the blocking signal as a new area to be processed, and entering S11 until the iteration number reaches a preset threshold value.
2. The method for selecting an intersection universal relay node applied to a vehicle networking of claim 1, wherein the S11 comprises:
dividing the region to be processed into region blocks with unequal widths according to a preset segmentation formula; wherein the preset segmentation formula is as follows:
wherein A is a compression coefficient, NpartIs the total number of region blocks, Wseg(k) The width of the kth region block.
3. The method for selecting the universal relay node for the intersections in the vehicle networking according to claim 1, wherein before broadcasting the blocking signal according to the time slot corresponding to the area block where the node is located, the method further comprises:
judging whether blocking signals sent by other candidate vehicle nodes are intercepted or not;
if so, the blocking signal is no longer transmitted.
4. The method for selecting an intersection universal relay node applied to a vehicle networking system according to claim 1, wherein the determining an intersection relay node from all the candidate relay nodes comprises:
and determining the intersection relay node from all the candidate relay nodes in a random selection mode.
5. The method for selecting the universal relay node for the intersections in the vehicle networking according to any one of claims 1 to 4, wherein the determining the branch relay nodes on the branches by the intersection relay node to complete the selection of the intersection relay node comprises:
the intersection relay node sends a request broadcast propagation packet to all target vehicle nodes on a branch road so that the target vehicle nodes can determine a branch road segmentation area corresponding to the current branch road, and the branch road segmentation area is used as the area to be processed to perform iterative segmentation processing to determine all branch road vehicle candidate nodes;
and the intersection relay node determines branch relay nodes from all the branch vehicle candidate nodes to complete the selection of the intersection relay nodes.
6. The method for selecting a universal relay node for an intersection in a vehicle networking system according to claim 5, wherein the determining the branch segmentation region corresponding to the current branch comprises:
judging whether the intersection relay node is positioned in the current branch or not;
if so, the branch division region corresponding to the current branch is a region in which the distance between the current branch and the intersection relay node along the message propagation direction is less than the vehicle communication distance;
if not, the branch dividing region corresponding to the current branch is a region corresponding to the optimal position of the current branch from the center position of the intersection in the current branch; and the optimal position is the position which is farthest from the center position of the intersection in the coverage area of the communication area of the intersection relay node on the current branch.
7. The utility model provides a be applied to vehicle networking's intersection general relay node selection system which characterized in that, is applied to the candidate vehicle node in the intersection region, the intersection region is for the region that uses intersection central point as the centre of a circle, and the circle that uses half of vehicle communication distance as the radius corresponds, the system includes:
the region determining module is used for determining intersection segmentation regions when a request broadcast propagation packet sent by a vehicle node is received; the request broadcast propagation packet is specifically a request broadcast propagation packet which is sent to all the candidate vehicle nodes in the intersection area when the vehicle node reaches the intersection area, and the intersection partition area is an area corresponding to a circle which takes the intersection center position as the center of the circle and takes the distance from the vehicle node to the intersection center position as the radius;
the relay node determination module is used for taking the intersection segmentation area as an area to be processed, performing iterative segmentation processing by using an iterative processing submodule, and determining all candidate relay nodes so that the vehicle node can determine the intersection relay node from all the candidate relay nodes, and determining a branch relay node on a branch through the intersection relay node to finish the selection of the intersection relay node;
wherein the iterative processing submodule comprises:
the dividing unit is used for dividing the region to be processed into region blocks with different widths according to a preset rule;
the broadcasting unit is used for broadcasting the blocking signal according to the time slot corresponding to the area block where the broadcasting unit is located;
and the determining unit is used for taking the area block corresponding to the vehicle node which has sent the blocking signal as a new area to be processed and starting the working process of the dividing unit until the iteration number reaches a preset threshold value.
8. The system for selecting universal relay nodes for use in vehicle networking intersections of claim 7 wherein the iterative process submodule further comprises:
the judging unit is used for judging whether the blocking signals sent by other candidate vehicle nodes are intercepted or not before the blocking signals are broadcasted according to the time slots corresponding to the area blocks where the judging unit is located; if so, the blocking signal is no longer transmitted.
9. An electronic device, comprising:
a memory for storing a computer program;
a processor for implementing the method of selecting an intersection universal relay node for use in a vehicle networking of any of claims 1 to 6 when executing the computer program.
10. A computer-readable medium for storing a computer program which, when executed by a processor, implements the intersection universal relay node selection method applied to the internet of vehicles according to any one of claims 1 to 6.
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