A V2X message filtering and forwarding system based on V2X vehicle network RSU

Abstract

The present invention relates to a V2X message filtering and forwarding system for a V2X (Vehicle-to-Everything) vehicle (V2X) network RSU (Relay State Unit) (RSU), belonging to the field of V2X (Vehicle-to-Everything) network. The system comprises: a message filtering module that removes invalid messages to be forwarded; a message update and fusion module that reduces redundant messages to be forwarded; a specific area forwarding module that extracts key information from messages to be forwarded, selects a forwarding area, and forwards them in a targeted manner via PC5 communication, based on a roadside information forwarding method based on electronic fences; and a message collaborative forwarding module that addresses the perception and communication blind spots of roadside nodes. Based on the road topology and local RSU deployment, the module utilizes other nodes through V2X communication to fill in blind spots. The nodes selectively forward relevant messages to other nearby RSU nodes to fill in blind spots and expand the node perception coverage. The system can improve the V2X message forwarding capability of RSUs in intelligent connected vehicle systems, expand the node perception range, and enhance the stability and reliability of V2X message communication in the V2X network system.

Description

Technical Field

[0001] The present invention belongs to the field of vehicle networking, and relates to a V2X message filtering and forwarding system based on a V2X vehicle networking RSU. Background Art

[0002] With the continuous advancement of V2X communication technology and the continuous improvement of the IoV technical standards system, the industrialization of the IoV is gradually accelerating. Roadside Units (RSUs) are key devices in the IoV vehicle-road cooperative system, primarily used to implement vehicle-road communication and roadside traffic awareness. In a V2X system, RSUs are typically deployed at intersections and key road sections. They receive information from cloud platforms, onboard vehicle units (OBUs), mobile environment controllers (MECs), traffic lights, and other RSUs. They process local road maps (MapData, MAP), vehicle motion information (Basic SafetyMessage, BSM), road sign information (Roadside Information, RSI), signal phase and timing messages (SPAT), traffic participant information (Roadside SafetyMessage, RSM), and high-precision positioning differential data. They then communicate with vehicles equipped with V2X communication equipment and provide real-time road and traffic status information to vehicles and pedestrians via I2V.

[0003] Existing research on RSUs has mostly focused on their deployment locations, energy consumption, and multi-RSU management. In the paper "Wang Z, Zheng J, Wu Y, et al. A centrality-based RSU deployment approach for vehicular ad hoc networks [C] / / 2017 IEEE International Conference on Communications (ICC). IEEE, 2017: 1-5," Zhenyu Wang et al. introduced the concept of centrality in social networks into RSU deployment and formulated the RSU deployment problem as a linear programming problem, effectively improving RSU deployment efficiency in terms of coverage time ratio. In the literature Adrian R, Sulistyo S, Mustika IW, et al. Roadside unit power saving using vehicle detection system in vehicular ad-hoc network [C] / / 2020 3rd International Seminar on Research of Information Technology and Intelligent Systems (ISRITI). IEEE, 2020: 198-202., Ronald Adrian et al. studied the power consumption load problem of RSU and proposed to embed a vehicle detection system (VDS) in the RSU to reasonably switch the active and sleep modes of the RSU to effectively reduce power consumption. In the literature Ni Y, Zhao C, Cai L. Hybrid RSU Management in Cybertwin-IoV for Temporaland Spatial Service Coverage [J]. IEEE Transactions on Vehicular Technology, 2021, 71 (5): 4596-4606., Yuanzhi Ni et al. studied the hybrid RSU deployment and management problem under the Cybertwin-IoV architecture and proposed a three-stage strategy to solve the optimization problem and meet the service load of different granularities. The functions for the targeted traffic scenarios are very simple, and they do not consider the diversity of messages that RSU needs to process and distribute in complex traffic scenarios, nor do they consider the problems of message forwarding redundancy and small message coverage in the vehicle-road cooperative perception system. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a V2X message filtering and forwarding system based on the V2X vehicle network RSU, which can forward messages in a targeted manner, reduce the amount of V2X message transmission, reduce the message receiving pressure of the vehicle terminal, and expand the node perception range.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A V2X message filtering and forwarding system based on a V2X vehicle network RSU, comprising a V2X message processing subsystem and a V2X message forwarding subsystem;

[0007] The V2X message processing subsystem includes a message filtering module and a message fusion and update module for reducing redundant messages and invalid messages;

[0008] The message filtering module is used to design a message filtering mechanism according to message attributes and filter messages;

[0009] The message fusion and update module is used to extract message types and key information, and design a message fusion and update mechanism based on the message source, so as to fuse similar messages from different sources and update similar messages from the same source;

[0010] The V2X message forwarding subsystem includes a specific area forwarding module and a message coordinated forwarding module, which are used to combine V2X message forwarding with actual road conditions and forward V2X messages to OBUs and other nearby RSUs in different forwarding areas.

[0011] The specific area forwarding module takes into account specific road conditions and adopts an environmentally aware adaptive electronic fence roadside information forwarding method. Based on the V2X communication blind area range and environmental perception information, it adaptively adjusts the electronic fence area, allocates multicast groups, and builds a dynamic forwarding area source table. For V2X messages to be forwarded to OBUs, the module calculates the correlation between the message and each electronic fence area based on the key information of the message and road driving rules. The electronic fence areas of the message are then determined based on the correlation, and the message is forwarded to OBUs located in different electronic fence areas using PC5 communication.

[0012] The message collaborative forwarding module combines the message type and basic attributes to analyze the impact range of the current roadside I2V message and the perception and recognition blind spots of other nearby nodes, and determines whether the message needs to be collaboratively distributed to other nearby nodes RSU. If necessary, the message is distributed based on the road topology and local RSU deployment status, and the message is forwarded to the target RSU via the Uu interface or optical fiber to expand the coverage of the roadside I2V message.

[0013] Furthermore, the message filtering mechanism designed by the message filtering module is a message filtering mechanism based on the spatiotemporal validity of messages, which specifically includes:

[0014] When an RSU receives a message from a different source, it first extracts the message's timestamp attribute. If the difference with the current timestamp is not within the permitted range, the time validity is not met and the message is discarded. If it is, the message's location attribute is extracted and compared with the current RSU forwarding range. If the message is not within the range, it is discarded. This mechanism filters out invalid messages and reduces the message forwarding pressure on the RSU.

[0015] Furthermore, the message fusion and update mechanism designed by the message fusion and update module is: a message fusion and update mechanism based on message timestamp and message type, specifically including:

[0016] Sort by timestamp, put different types of messages into different source message tables, and record their message source device IDs. When a newly arrived message is of the same type but from a different source, extract the message key information and timestamp, and compare it with the messages with the smaller timestamp difference in the source table of this type of message. Messages with key information within the error range are merged, and their message source device IDs are modified to make the message to be forwarded more detailed. When a message of the same type and source is received, extract its ID and timestamp. If the ID is the same and the timestamp difference is within the allowable range, overwrite the message to update it.

[0017] Furthermore, the method for forwarding roadside information based on environment-aware adaptive electronic fence specifically includes the following steps:

[0018] Combine roadside MEC, radar, and cameras to obtain current environmental perception information and adaptively adjust the scope of the electronic fence in real time;

[0019] Allocate multicast groups and build a dynamic forwarding area table containing adaptive electronic fence areas and multicast groups. When the roadside equipment (RSU) broadcasts a message, the information in the dynamic forwarding area table is broadcasted.

[0020] When a V2X message needs to be forwarded to the OBU, the association between the V2X message and each electronic fence area in the dynamic forwarding area table is calculated and recorded in the message header;

[0021] Before forwarding the V2X message, the message is sent from different multicast groups based on the V2X message header information and the dynamic forwarding zone table;

[0022] When a vehicle carrying an on-board unit (OBU) enters the broadcast range of a roadside unit (RSU), it receives information from a dynamic forwarding area table, determines its electronic fence area based on its own location information, and chooses to join the corresponding broadcast group to obtain I2V messages related to the current road section. When the vehicle leaves the area, it automatically leaves the multicast group.

[0023] Furthermore, the message cooperative forwarding module distributes messages based on nearby node perception and communication blind spots, road topology, and local RSU deployment, specifically including:

[0024] The current RSU pre-records the perception and communication blind spot range of nearby nodes, the local road topology, and RSU equipment information. When a message arrives, the affected nearby roads are judged and the collaborative roadside nodes are determined based on the impact range of the message and the perception and communication blind spot range of the collaborative roadside nodes, combined with the local road topology and the deployment of nearby RSUs. If the affected collaborative node has an RSU deployed, the message is forwarded to its corresponding RSU; if no RSU is deployed, it is forwarded to its nearby RSUs, expanding the perception range of the nearby collaborative node RSUs and reducing blind spots.

[0025] Furthermore, the dynamic forwarding zone table is constructed based on the environment perception information, and the specific construction method is as follows:

[0026] First, considering actual road conditions and under normal weather conditions, the V2X communication blind spots at intersections were measured. Areas where V2X communication was normal at the intersection were not included in the geo-fence area, thereby preliminarily determining the geo-fence areas.

[0027] Then, a multicast group is assigned to each electronic fence area, and a forwarding area table is constructed including the electronic fence area ID, electronic fence area range and multicast group;

[0028] Finally, considering the impact of environmental perception information on the V2X forwarding range, on the one hand, weather impact is classified into different levels. Real-time weather information is obtained through sensing devices. When heavy fog, rain, or snow is detected, the MEC device is combined to determine the weather impact level and adaptively modify the geo-fence area. On the other hand, when sensing devices such as cameras identify that a certain road section is temporarily closed to vehicles, the corresponding geo-fence area and multicast group are disabled, meaning no messages are forwarded to that area. These messages are then re-enabled when the road is reopened. Through this mechanism, a dynamic forwarding area table is constructed.

[0029] Furthermore, the calculation method of the electronic fence area range is as follows:

[0030] Based on specific road conditions, survey the V2X communication blind spot range and pre-set the electronic fence area to be divided into N parts. Each part is described by a set. Each element consists of the longitude and latitude of the section center and the distance from the section center to the section edge. The number of elements in the set is no less than 2.

[0031] For A pre part:

[0032] A pre ={(Lon1, Lat1, W1), (Lon2, Lat2, W2), ..., (Lon n , Lat n , W n )};

[0033] Among them, Lon i 、Lat i (i=0,1,2,……) are the longitude and latitude of the center of the road section, W i , is the distance from the center of the road section to the edge of the road section;

[0034] Considering the impact of weather factors on the V2X forwarding range, radar and cameras are used to obtain weather information and send it to the MEC device. Based on the degree of weather impact on the V2V communication range, the MEC device calculates the weather impact level and notifies the RSU. The RSU then expands the electronic fence area to different sizes toward the intersection based on the weather impact level. In other words, the actual calculation method for the range of the electronic fence area is as follows:

[0035] A ac ={A pre , (k×ΔLon, k×ΔLat, W)};

[0036] Among them, A ac is the actual range of the electronic fence area, k is the weather impact factor, ΔLon and ΔLat are preset values, indicating the longitude and latitude increased by the weather, and W is the preset distance to the edge of the road section. When k = 0, W = 0, otherwise W is the preset initial value. Therefore, (k × ΔLon, k × ΔLat, W) represents the range of the electronic fence area increased by the weather;

[0037] The rest of the electronic fence area is the same as A pre The electronic fence area is adjusted adaptively.

[0038] Furthermore, for the V2X message to be forwarded to the OBU, the correlation between the message and each electronic fence area is calculated based on the key information of the message and the road driving rules, specifically including:

[0039] For different types of messages, different key information is extracted. Then, based on the enabled items in the dynamic forwarding area table and the current road traffic rules at the intersection, the association degree d between the message and each electronic fence area is determined. The association degree d takes a value of 1 or 0. A value of 1 indicates that the area is associated with the message and needs to be forwarded, while a value of 0 indicates the opposite. After the determination is completed, the forwarding area ID with a value of 1 is recorded in the message header as the basis for subsequent forwarding area selection.

[0040] The beneficial effects of the present invention are as follows: the present invention mainly addresses the problems of message forwarding redundancy and limited message coverage of a single roadside node in the vehicle-road cooperative perception system. On the one hand, the V2X message processing subsystem filters redundant and invalid messages, and at the same time integrates information from different sources and updates homologous messages, thereby increasing the forwarding volume of valid V2X messages; on the other hand, the V2X message forwarding subsystem combines V2X messages with actual road conditions to achieve targeted forwarding, reduce the amount of V2X messages sent, reduce the receiving pressure on the on-board terminal, and distribute messages to nearby cooperative nodes RSU, thereby increasing the coverage range of valid V2X messages.

[0041] Other advantages, objects, and features of the present invention will be described in part in the following description and, in part, will be apparent to those skilled in the art upon examination of the following description or may be learned from practice of the present invention. The objects and other advantages of the present invention may be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below with reference to the accompanying drawings, in which:

[0043] Figure 1 Schematic diagram of the overall architecture of the system of the present invention;

[0044] Figure 2 This is the V2X message processing subsystem architecture diagram;

[0045] Figure 3 This is the flow chart of the message filtering mechanism;

[0046] Figure 4 This is a schematic diagram of the message fusion and update mechanism;

[0047] Figure 5 This is the architecture diagram of the V2X message forwarding subsystem;

[0048] Figure 6 Construct a flow chart for the dynamic forwarding zone table;

[0049] Figure 7 Determine the schematic diagram of the electronic fence area;

[0050] Figure 8 Schematic diagram of the forwarding zone selection mechanism;

[0051] Figure 9 This is a schematic diagram of collaborative message forwarding. DETAILED DESCRIPTION

[0052] The following describes the embodiments of the present invention by means of specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0053] Among them, the accompanying drawings are only for illustrative purposes and represent only schematic diagrams rather than actual pictures, and should not be understood as limiting the present invention. In order to better illustrate the embodiments of the present invention, some parts of the accompanying drawings may be omitted, enlarged or reduced, and do not represent the dimensions of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions may be omitted in the accompanying drawings.

[0054] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "back", etc. indicating directions or positional relationships, they are based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0055] Figure 1 It is an overall framework of a V2X message filtering and forwarding system based on the V2X vehicle network RSU, which includes two subsystems: V2X message processing subsystem and V2X message forwarding subsystem.

[0056] like Figure 2 As shown, the V2X message processing subsystem reduces redundant and invalid messages and increases the forwarding volume of valid V2X messages, including: a message filtering module and a message fusion and update module;

[0057] Message filtering modules, such as Figure 3As shown, when RSU receives messages from different sources, it determines their spatiotemporal validity and filters the messages;

[0058] A message filtering mechanism is adopted. When a new message arrives, its timestamp is first extracted and the difference operation is performed with the current timestamp. When the difference is less than the predetermined range, the message is judged to have time validity. Then, the location information of the message is further extracted to check whether it needs to be forwarded to the forwarding geographical range predetermined by this RSU, that is, to determine whether the message affects the traffic participants within the coverage range of this RSU. If so, it is judged to have spatial validity and placed in the source message table, waiting for subsequent forwarding.

[0059] Message fusion update module, such as Figure 4 As shown, the filtered information records its message source, that is, the source device ID of the message, and is placed in the corresponding source message table according to the following mechanism based on its message type.

[0060] A message fusion and update mechanism is adopted. Taking the BSM message whose message source is OBU as an example, according to the message type, the message with a time difference less than a predetermined range is searched in the BSM source message table, and the message source device ID is compared. If it comes from the OBU, only its timestamp is modified to update the message; if it comes from the MEC unit, that is, the message source device ID is different, the message source and key information such as type, size, location and heading angle are extracted, and fused with the key information of the message, and its message source device ID and timestamp are modified to make the message to be forwarded more detailed.

[0061] like Figure 5 As shown in the figure, the V2X message forwarding subsystem combines V2X messages with actual road conditions to achieve targeted forwarding. It mainly includes: a specific area forwarding module and a message collaborative forwarding module;

[0062] The specific area forwarding module needs to pre-build a dynamic forwarding area table based on the environment perception information, such as Figure 6 As shown in the figure, based on actual road conditions and normal weather conditions, the V2X communication blind spot at the intersection is measured to preliminarily determine the geo-fence area. A corresponding multicast group is then assigned to each geo-fence area, and a forwarding zone table is constructed, including information such as the geo-fence area ID, geo-fence area range, and multicast group. Considering the impact of environmental perception information on the V2X forwarding range, the degree of weather impact is divided into four levels. Weather conditions are acquired using radar, cameras, or other sensing devices. This information is calculated by the MEC device to determine the weather impact level and sent to the RSU, enabling adaptive adjustment of the geo-fence area range. Furthermore, when the camera detects that a certain area is prohibited from passing, the corresponding entry in the dynamic forwarding zone table is disabled, meaning that messages will no longer be forwarded to that area.

[0063] like Figure 7 As shown in the figure, the calculation method of the electronic fence area range is based on the following two-way intersection as an example:

[0064] Based on the specific road conditions, the V2X communication blind spot range is surveyed, and the preset electronic fence area range is divided into eight parts for the incoming and outgoing sections in four directions. Each part is described by a set. Each element consists of the longitude and latitude of the section center and the distance from the section center to the edge of the section. The number of elements in the set is not less than 2.

[0065] Assume that the eight parts of the preset electronic fence area are set A pre 、B pre 、C pre 、D pre 、E pre 、F pre , G pre 、H pre , with set A pre For example:

[0066] A pre ={(Lon1, Lat1, W1), (Lon2, Lat2, W2), ..., (Lon n , Lat n , W n )};

[0067] Among them, Lon i 、Lat i (i=0,1,2,......) are the longitude and latitude of the center of the road section, W i , is the distance from the center of the road section to the edge of the road section.

[0068] Considering the impact of weather factors on the V2X forwarding range, radar and cameras are used to obtain weather information and send it to the MEC device. The degree of weather impact on the V2V communication range is divided into four levels: 0, 1, 2, and 3, from low to high. The MEC device calculates this level and notifies the RSU. The RSU then expands the electronic fence area toward the intersection to varying degrees based on the weather impact level. The actual calculation method for the range of the electronic fence area is:

[0069] A ac ={A pre , (k×ΔLon, k×ΔLat, W)};

[0070] Among them, A acis the actual range of the electronic fence area, k is the weather impact factor, ΔLon and ΔLat are preset values, indicating the longitude and latitude increased by the weather, W is the preset distance to the edge of the road section, when k = 0, W = 0, otherwise W is the preset initial value, so (k × ΔLon, k × ΔLat, W) represents the range of the electronic fence area increased by the weather. The above only gives A ac The calculation method of the area is the same as that of other electronic fence areas, so the scope of the electronic fence area is adjusted adaptively.

[0071] When the camera detects that a certain area is prohibited from access, it notifies the RSU of this information. The entry corresponding to the electronic fence area in the dynamic forwarding area table inside the RSU will be disabled, that is, no messages will be forwarded to the multicast group. When it is identified that the area is restored to access, the corresponding entry will be re-enabled.

[0072] Forwarding zone selection mechanism, such as Figure 8 As shown, for different message types, different key information is extracted. Then, based on the dynamic forwarding zone table and the current intersection traffic rules, the degree of association d between the message and each electronic fence zone is determined. The degree of association d takes values ​​of 1 or 0. A value of 1 indicates that the forwarding zone is associated with the message and needs to be forwarded, while a value of 0 indicates the opposite. After the calculation is complete, this information is recorded in the message header. Before V2X message forwarding, the message is sent from different multicast groups based on this header information and the dynamic forwarding zone table. When a vehicle carrying an on-board unit (OBU) enters the broadcast range of a roadside unit (RSU), it receives the dynamic forwarding zone table information and chooses to join the corresponding broadcast group based on its location to obtain information about the current road section. Upon leaving the area, the vehicle automatically leaves the multicast group.

[0073] The message collaborative forwarding module analyzes the impact range of the current roadside I2V message based on the message type and basic attributes, and determines whether the message needs to be collaboratively distributed to other nearby nodes RSU based on conditions such as nearby node perception and recognition blind spots and message relevance. If necessary, a message distribution mechanism based on nearby node perception and communication blind spots, road topology, and local RSU deployment is adopted to forward the message to the target RSU via the Uu interface or optical fiber, thereby expanding the coverage of the roadside I2V message.

[0074] Message distribution mechanism based on nearby node perception and communication blind spots, road topology, and local RSU deployment: The current RSU pre-records nearby node perception and communication blind spots, local road topology, and RSU device information. When a message arrives, it determines the nearby roads affected by the message and the collaborative roadside nodes’ perception and communication blind spots based on the local road topology and nearby RSU deployment, and determines the collaborative roadside nodes. To explain this mechanism in detail, the following example is given: Figure 9 As shown in the figure, RSU1 and RSU2 are two roadside unit devices described in this article, which have V2X communication functions. The two circular dotted lines are the PC5 communication ranges of the two RSUs respectively, and within their respective areas, there are two vehicles Car1 and Car2 carrying OBUs. RSU1 and RSU2 internally record the current local road topology and the deployment of nearby RSUs. When the vehicle Car1 within the coverage area of ​​RSU1 drives abnormally, RSU1 obtains its vehicle abnormality information and needs to send the message to other vehicles within its coverage area (if any). At the same time, based on the impact range of the message, the current local road topology and the deployment of nearby RSUs, it is determined that the message will affect the vehicles within the coverage area of ​​the collaborative roadside node RSU2, and the message is within the perception blind spot of RSU2. RSU1 needs to send the message to RSU2 via the Uu interface or optical fiber communication method. RSU2 forwards the message to the vehicle Car2 located in its coverage area, thereby effectively expanding the coverage of the message.

[0075] The above-mentioned V2X message filtering and forwarding system includes the following steps:

[0076] Step 1: In a V2X system, the roadside unit (RSU) receives a large number of messages from various units. Based on the message timestamp and location information, the RSU determines their temporal and spatial validity and filters the messages. The filtered messages are placed into different source message tables based on their type. Before being placed into the source message table, the forwarded messages are further merged or updated through fusion and update mechanisms based on the message source and key information.

[0077] Step 2: For messages that need to be forwarded to the OBU, a dynamic forwarding zone table must be constructed before the entire message is forwarded. This facilitates subsequent forwarding zone selection. This step involves measuring the V2X communication blind spot at the intersection under normal weather conditions, preliminarily dividing the geo-fence area, and assigning multicast groups to each geo-fence area. This forwarding zone table includes information such as the geo-fence area ID, geo-fence area, and multicast group. Furthermore, considering the impact of environmental perception on the V2X forwarding range, radar, cameras, or other sensing devices are used to detect weather conditions. The MEC device then calculates the weather impact level and adaptively adjusts the geo-fence area. Furthermore, when a camera detects a restricted area, the corresponding entry in the dynamic forwarding zone table is disabled, and the forwarding zone table is dynamically modified. Messages to be forwarded are then retrieved from each source message table, and key information is extracted for each message type. The dynamic forwarding zone table and the current traffic regulations at the intersection are used to determine the message's relevance to each geo-fence area. After the calculation is complete, this information is recorded in the message header. Before forwarding the V2X message, the message content is sent from different multicast groups via PC5 communication based on this header information and the dynamic forwarding zone table. Finally, when a vehicle carrying an on-board unit (OBU) enters the broadcast range of the roadside unit (RSU), it receives the dynamic forwarding zone table information, determines its location within the geo-fence area, and chooses to join the corresponding broadcast group to obtain I2V messages related to the current road section. When leaving the area, the vehicle automatically leaves the multicast group.

[0078] Step 3: For messages that need to be forwarded to nearby RSUs, such as certain I2V messages, it is necessary to extract the key information of the message and combine it with the pre-recorded nearby node perception and communication blind spots, local road topology, and RSU equipment information to determine the impact range of the roadside I2V message, determine whether it needs to be forwarded and the forwarding range, and then forward the message to the RSU of the collaborative roadside node through the Uu interface or optical fiber communication method.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions, which should all be included in the scope of the claims of the present invention.

Claims

1. A V2X message filtering and forwarding system based on a V2X vehicle network RSU, characterized by: Includes V2X message processing subsystem and V2X message forwarding subsystem; The V2X message processing subsystem includes a message filtering module and a message fusion and update module for reducing redundant messages and invalid messages; The message filtering module is used to design a message filtering mechanism according to message attributes and filter messages; The message fusion and update module is used to extract message types and key information, and design a message fusion and update mechanism based on the message source, so as to fuse similar messages from different sources and update similar messages from the same source; The V2X message forwarding subsystem includes a specific area forwarding module and a message coordinated forwarding module, which are used to combine V2X message forwarding with actual road conditions and forward V2X messages to OBUs and other nearby RSUs in different forwarding areas. The specific area forwarding module considers specific road conditions and adopts an environment-aware adaptive electronic fence roadside information forwarding method. Based on the V2X communication blind area range and environment-aware information, it adaptively adjusts the electronic fence area, allocates multicast groups, and builds a dynamic forwarding area source table. For V2X messages to be forwarded to OBUs, the association between the message and each geo-fence area is calculated based on the key information of the message and road driving rules. The geo-fence areas of the message are then determined based on the association, and the message is forwarded to the OBUs located in different geo-fence areas using PC5 communication. The message collaborative forwarding module analyzes the impact range of the current roadside I2V message and the perception and recognition blind spots of other nearby nodes based on the message type and basic attributes, and determines whether the message needs to be collaboratively distributed to other nearby nodes RSU. If so, the message is distributed based on the road topology and local RSU deployment, and the message is forwarded to the target RSU via the Uu interface or optical fiber to expand the coverage of the roadside I2V message. The method for forwarding roadside information based on environment-aware adaptive electronic fence specifically includes the following steps: Combine roadside MEC, radar, and cameras to obtain current environmental perception information and adaptively adjust the scope of the electronic fence in real time; Allocate multicast groups and build a dynamic forwarding area table containing adaptive electronic fence areas and multicast groups. When the roadside equipment (RSU) broadcasts a message, the information in the dynamic forwarding area table is broadcasted. When a V2X message needs to be forwarded to the OBU, the association between the V2X message and each electronic fence area in the dynamic forwarding area table is calculated and recorded in the message header; Before forwarding the V2X message, the message is sent from different multicast groups based on the V2X message header information and the dynamic forwarding zone table; When a vehicle carrying an on-board unit (OBU) enters the broadcast range of a roadside unit (RSU), it receives information from the dynamic forwarding area table, determines its location in the electronic fence area based on its own location information, and chooses to join the corresponding broadcast group to obtain I2V messages related to the current road section. When leaving the area, the vehicle automatically leaves the multicast group. The dynamic forwarding zone table is constructed based on the environment perception information, and the specific construction method is as follows: First, considering actual road conditions and under normal weather conditions, the V2X communication blind spots at intersections were measured. Areas where V2X communication was normal at the intersection were not included in the geo-fence area, thereby preliminarily determining the geo-fence areas. Then, a multicast group is assigned to each electronic fence area, and a forwarding area table is constructed including the electronic fence area ID, electronic fence area range and multicast group; Finally, consider the impact of environmental perception information on the V2X forwarding range. On the one hand, weather impacts are classified into different levels, and sensing devices are used to obtain surrounding weather information in real time. When heavy fog, rain, or snow is detected, the MEC device is combined to determine the weather impact level and adaptively modify the electronic fence area. On the other hand, when sensing devices such as cameras identify that a certain road section is temporarily closed to vehicles, the corresponding electronic fence area and multicast group are disabled. That is, no messages are forwarded to this area. They are reactivated when the road is reopened. The calculation method of the electronic fence area range is as follows: Based on specific road conditions, survey the V2X communication blind spot range and pre-set the electronic fence area to be divided into N parts. Each part is described by a set. Each element consists of the longitude and latitude of the section center and the distance from the section center to the section edge. The number of elements in the set is no less than 2. For A pre part: AND pre ={(Lon1,Lat1,W1),(Lon2,Lat2,W2),……,(Lon n ,Years n ,IN n )}; Among them, Lon i 、Lat i (i=0, 1, 2, ...) are the longitude and latitude of the center of the road section, W i , is the distance from the center of the road section to the edge of the road section; Considering the impact of weather factors on the V2X forwarding range, radar and cameras are used to obtain weather information and send it to the MEC device. Based on the degree of weather impact on the V2V communication range, the MEC device calculates the weather impact level and notifies the RSU. The RSU then expands the electronic fence area to different sizes toward the intersection based on the weather impact level. In other words, the actual calculation method for the range of the electronic fence area is as follows: A ac ={A pre ,(k×ΔLon,k×ΔLat,W)}; Among them, A ac is the actual range of the electronic fence area, k is the weather impact factor, ΔLon and ΔLat are preset values, indicating the longitude and latitude increased by the weather, and W is the preset distance to the edge of the road section. When k = 0, W = 0, otherwise W is the preset initial value. Therefore, (k × ΔLon, k × ΔLat, W) represents the range of the electronic fence area increased by the weather; The rest of the electronic fence area is the same as A pre Part of it is the same, so as to adaptively adjust the range of the electronic fence area; For the V2X message to be forwarded to the OBU, the correlation between the message and each electronic fence area is calculated based on the key information of the message and the road driving rules, specifically including: For different types of messages, different key information is extracted. Then, based on the enabled items in the dynamic forwarding area table and the current road traffic rules at the intersection, the association degree d between the message and each electronic fence area is determined. The association degree d takes a value of 1 or 0. A value of 1 indicates that the area is associated with the message and needs to be forwarded, while a value of 0 indicates the opposite. After the determination is completed, the forwarding area ID with a value of 1 is recorded in the message header as the basis for subsequent forwarding area selection.

2. The V2X message filtering and forwarding system based on the V2X vehicle network RSU according to claim 1 is characterized in that: The message filtering mechanism designed by the message filtering module is a message filtering mechanism based on the spatiotemporal validity of messages, which specifically includes: When RSU receives a message from a different source, it first extracts the timestamp attribute of the message. If the difference with the current timestamp is not within the allowed range, the time validity is not met and the message is discarded. If it is met, it continues to extract the location attribute of the message and compares it with the current RSU forwarding range. If the message is not within the range, the message is discarded.

3. The V2X message filtering and forwarding system based on the V2X vehicle network RSU according to claim 1 is characterized in that: The message fusion and update mechanism designed by the message fusion and update module is a message fusion and update mechanism based on message timestamp and message type, specifically including: Sort by timestamp, put different types of messages into different source message tables, and record their message source device IDs. When a newly arrived message is of the same type but from a different source, extract the message key information and timestamp, and compare it with the messages with the smaller timestamp difference in the source table of this type of message. Messages with key information within the error range are merged, and their message source device IDs are modified to make the message to be forwarded more detailed. When a message of the same type and source is received, extract its ID and timestamp. If the ID is the same and the timestamp difference is within the allowable range, overwrite the message to update it.

4. The V2X message filtering and forwarding system based on the V2X vehicle network RSU according to claim 1 is characterized in that: The message cooperative forwarding module distributes messages based on nearby node perception and communication blind spots, road topology, and local RSU deployment, specifically including: The current RSU pre-records the perception and communication blind spot range of nearby nodes, the local road topology, and RSU equipment information. When a message arrives, the affected nearby roads are judged and the collaborative roadside nodes are determined based on the impact range of the message and the perception and communication blind spot range of the collaborative roadside nodes, combined with the local road topology and the deployment of nearby RSUs. If the affected collaborative node has an RSU deployed, the message is forwarded to its corresponding RSU; if no RSU is deployed, it is forwarded to its nearby RSUs, expanding the perception range of the nearby collaborative node RSUs and reducing blind spots.

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