WO2022193511A1 - Map data transmission method and system, edge server, and storage medium - Google Patents

Abstract

Embodiments of the present application provide a map data transmission method and system, an edge server, and a storage medium. A vehicle-mounted device transmits a map data distribution request to a roadside communication unit by means of a vehicle-mounted communication unit; after receiving the request, the roadside communication unit obtains the signal intensity of a communication channel with the vehicle-mounted communication unit, and transmits the signal intensity to an edge server; the edge server sets the packet size and the data packet transmission frequency according to the signal intensity, divides map data into a plurality of data packets according to the packet size, and transmits the data packets to a vehicle-mounted subsystem according to the data packet transmission frequency. Because the edge server sets the packet size and the data packet transmission frequency on the basis of the signal intensity, the effect of the communication quality of a communication channel on map data transmission is reduced, and the data packet transmission efficiency is ensured as much as possible. In this way, a vehicle-mounted device can obtain map data on the basis of received data packets, so that the efficiency of acquiring map data by a vehicle is improved.

Description

A map data transmission method, system, edge server and storage medium

This application claims the priority of the Chinese patent application filed on March 18, 2021 with the application number of 202110288305.7 and the application title of "A Map Data Transmission Method, System, Edge Server and Storage Medium", the entire contents of which are Incorporated herein by reference.

technical field

The present application relates to the technical field of smart cars, and in particular, to a map data transmission method, system, edge server and storage medium.

Background technique

V2X (Vehicle to everything, vehicle to anything) technology is a vehicle networking technology that realizes information interaction between vehicles and the outside world through relevant protocol standards, including V2V (Vehicle to Vehicle, vehicle-to-vehicle), V2I (Vehicle to Infrastructure, vehicle-to-vehicle) technology infrastructure), V2P (Vehicle to Pedestrian, vehicle to pedestrian) and V2N (Vehicle to Network, vehicle to Internet), etc., V2X is one of the key technologies to realize autonomous driving.

Timely acquisition of map data by vehicles is an important factor in realizing autonomous driving. The current solutions for vehicles to acquire map data are mainly: using 4G/5G technology, through Uu interface (WCDMA (Wideband Code Division Multiple Access, Wideband Code Division Multiple Access) system An interface) to obtain map data from the cloud server. In the process of acquiring map data, it needs to consume a lot of mobile traffic, and is easily affected by network signals and network speed, resulting in poor efficiency of vehicle acquisition of map data.

SUMMARY OF THE INVENTION

The purpose of the embodiments of the present application is to provide a map data transmission method, system, edge server, and storage medium, so as to improve the efficiency of vehicle acquisition of map data. The specific technical solutions are as follows:

In a first aspect, an embodiment of the present application provides a method for transmitting map data, including:

The in-vehicle device sends a map data distribution request to the roadside communication unit through the in-vehicle communication unit;

The roadside communication unit receives the map data distribution request, acquires the signal strength of the communication channel with the vehicle-mounted communication unit, and sends the signal strength to the edge server;

The edge server sets the packet size and the data packet sending frequency according to the signal strength, divides the map data into multiple data packets according to the packet size, and sends the data packets through the road according to the packet sending frequency. The side communication unit and the in-vehicle communication unit transparently transmit each data packet to the in-vehicle device;

The in-vehicle device obtains the map data based on the received data packets.

Optionally, the step of the on-board equipment sending a map data distribution request to the roadside communication unit through the on-board communication unit includes:

When the vehicle on which the in-vehicle device is installed drives into the operational design domain of the roadside communication unit, the in-vehicle device sends a map data distribution request to the roadside communication unit through the in-vehicle communication unit.

Optionally, the step of the on-board equipment sending a map data distribution request to the roadside communication unit through the on-board communication unit includes:

The in-vehicle device sends a basic safety message to the roadside communication unit through the in-vehicle communication unit, wherein the preset flag bit in the basic safety message is set as a flag value representing a request for the edge server to distribute map data;

The step of receiving the map data distribution request by the roadside communication unit includes:

The roadside communication unit receives the basic safety message, and identifies the preset flag bit in the basic safety message. If it is identified that the preset flag bit is set to represent a request for the edge server to distribute map data If the flag value is set, it is determined that a map data distribution request is received.

Optionally, there is a one-to-many correspondence between the edge server and the roadside communication unit;

The step of the roadside communication unit sending the signal strength to the edge server includes:

The roadside communication unit sends the signal strength to the edge server corresponding to the roadside communication unit.

Optionally, the step of setting the packet size and the data packet sending frequency by the edge server according to the signal strength includes:

If the signal strength is less than or equal to the first threshold, the edge server sets the packet size to a value greater than or equal to the first set value, and sets the data packet sending frequency to a value greater than or equal to the second set value value;

If the signal strength is greater than the first threshold and less than or equal to the second threshold, the edge server sets the packet size to a value that is less than the first set value and greater than or equal to a third set value, Setting the data packet sending frequency to a value less than the second set value and greater than or equal to the fourth set value;

If the signal strength is greater than the second threshold, the edge server sets the packet size to a value less than the third set value, and sets the data packet sending frequency to a value less than the fourth set value value.

Optionally, the value range of the first threshold is 12-21.5dBm, the value range of the second threshold is 21.5-25dBm, the value range of the first set value is 5-8kB, and the The value range of the second set value is 50-100Hz, the value range of the third set value is 2-5kB, and the value range of the fourth set value is 10-50Hz.

Optionally, before the edge server transparently transmits each data packet to the in-vehicle device through the roadside communication unit and the in-vehicle communication unit according to the transmission frequency of the data packet, the method further includes: :

The roadside communication unit sends sub-packet information to the vehicle-mounted communication unit, wherein the sub-packet information includes the total number of divided data packets and the identification information of each data packet;

The method also includes:

The in-vehicle communication unit receives the packet information, and if it is determined based on the packet information that packet loss occurs in the process of receiving each data packet, it sends a data packet retransmission request to the roadside communication unit. , so as to request the roadside communication unit to resend the data packets that have lost packets until all the data packets are successfully received.

Optionally, after the step of receiving the subcontracting information by the on-board communication unit, the method further includes:

The in-vehicle communication unit establishes an empty data packet sequence according to the total number of data packets;

The in-vehicle communication unit records the identification information of each data packet into the data packet sequence in sequence;

After the edge server transparently transmits each data packet to the in-vehicle device through the roadside communication unit and the in-vehicle communication unit according to the transmission frequency of the data packet, the method further includes:

The roadside communication unit sends an end message to the vehicle-mounted communication unit;

The in-vehicle communication unit receives the packet information, and if it is determined based on the packet information that packet loss occurs in the process of receiving each data packet, it sends a data packet retransmission request to the roadside communication unit. steps, including:

After receiving the end message, the on-board communication unit compares the identification information of the received data packet with the identification information recorded in the data packet sequence. If the identification information of the data packet is obtained, a data packet retransmission request is sent to the roadside communication unit, wherein the data packet retransmission request carries the identification information of the unreceived data packet.

In a second aspect, an embodiment of the present application provides a method for transmitting map data, including:

The edge server receives the signal strength sent by the roadside communication unit, where the signal strength is the relationship between the roadside communication unit and the roadside communication unit obtained by the roadside communication unit after receiving the map data distribution request sent by the vehicle communication unit. the signal strength of the communication channel between the onboard communication units;

The edge server sets the packet size and the data packet sending frequency according to the signal strength;

The edge server divides the map data into multiple data packets according to the packet size;

The edge server transparently transmits each data packet to the in-vehicle device through the roadside communication unit and the in-vehicle communication unit according to the transmission frequency of the data packet, so that the in-vehicle device obtains the data packet based on the received data packet. the map data.

Optionally, the step of setting the packet size and data packet sending frequency according to the signal strength includes:

If the signal strength is less than or equal to the first threshold, then the packet size is set to a value greater than or equal to the first set value, and the packet transmission frequency is set to a value greater than or equal to the second set value;

If the signal strength is greater than the first threshold and less than or equal to the second threshold, set the packet size to a value smaller than the first set value and greater than or equal to the third set value, and set the packet transmission The frequency is a value less than the second set value and greater than or equal to the fourth set value;

If the signal strength is greater than the second threshold, the packet size is set to a value smaller than the third set value, and the data packet transmission frequency is set to a value less than the fourth set value.

Optionally, the value range of the first threshold is 12-21.5dBm, the value range of the second threshold is 21.5-25dBm, the value range of the first set value is 5-8kB, and the The value range of the second set value is 50-100Hz, the value range of the third set value is 2-5kB, and the value range of the fourth set value is 10-50Hz.

In a third aspect, an embodiment of the present application provides a map data transmission system, including: a vehicle-mounted terminal and a roadside terminal; the vehicle-mounted terminal includes a vehicle-mounted device and a vehicle-mounted communication unit; the roadside terminal includes a roadside communication unit and an edge server; the on-board communication unit and the roadside communication unit are connected through a communication channel;

the in-vehicle device, configured to send a map data distribution request to the roadside communication unit through the in-vehicle communication unit;

the roadside communication unit, configured to receive the map data distribution request, obtain the signal strength of the communication channel with the vehicle-mounted communication unit, and send the signal strength to the edge server;

The edge server is configured to set the packet size and the data packet sending frequency according to the signal strength, divide the map data into multiple data packets according to the packet size, and send the data packets through the The roadside communication unit and the vehicle-mounted communication unit transparently transmit each data packet to the vehicle-mounted device;

The in-vehicle device is further configured to obtain the map data based on the received data packets.

In a fourth aspect, an embodiment of the present application provides an edge server, including a processor and a memory;

the memory for storing computer programs;

The processor is configured to implement the method provided by the second aspect of the embodiments of the present application when executing the computer program stored in the memory.

In a fifth aspect, an embodiment of the present application provides a storage medium, where a computer program is stored in the storage medium, and the computer program implements the method provided by the second aspect of the embodiment of the present application when the computer program is executed by a processor.

In a sixth aspect, the embodiments of the present application provide a computer program product including instructions, which, when run on a computer, cause the computer to execute the method provided by the second aspect of the embodiments of the present application.

In the map data transmission method, system, edge server, and storage medium provided by the embodiments of the present application, the vehicle-mounted device sends a map data distribution request to the roadside communication unit through the vehicle-mounted communication unit to request the roadside end to distribute the map data, and the roadside communication unit sends a map data distribution request to the roadside communication unit. After receiving the map data distribution request, obtain the signal strength of the communication channel with the vehicle communication unit, and send the obtained signal strength to the edge server. The edge server sets the packet size and data packet sending frequency according to the signal strength, and then The map data is divided into multiple data packets according to the packet size, and each data packet is sent to the vehicle subsystem according to the data packet transmission frequency. The transmission distance between the in-vehicle communication unit and the roadside communication unit is relatively short, and since the edge server sets the packet size and data packet transmission frequency based on the signal strength, the impact of the communication quality of the communication channel on the map data transmission is reduced as much as possible. This ensures the efficiency of data packet transmission, so that the in-vehicle device can obtain map data based on each received data packet, thereby improving the efficiency of the vehicle in obtaining map data.

Description of drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments of the present application. For those of ordinary skill in the art, other embodiments can also be obtained according to these drawings without creative efforts.

1 is a schematic flowchart of a map data transmission method according to an embodiment of the application;

2 is a schematic flowchart of another map data transmission method according to an embodiment of the application;

3 is a schematic structural diagram of a map data transmission system according to an embodiment of the application;

FIG. 4 is a schematic diagram under an example scenario of an embodiment of the present application;

FIG. 5 is a schematic diagram of the internal structure of each subsystem of the connected vehicle system according to the embodiment of the application;

FIG. 6 is a schematic flowchart of the internal interaction of the vehicle linkage system according to the embodiment of the application;

7 is a schematic diagram of a specific flow of roadside high-precision map data distribution according to an embodiment of the present application;

FIG. 8 is a schematic flowchart of a transparent transmission of data packets between an in-vehicle device and a roadside device according to an embodiment of the present application;

FIG. 9 is a schematic structural diagram of an edge server according to an embodiment of the present application.

Detailed ways

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art based on the present application fall within the protection scope of the present application.

In order to improve the efficiency of vehicle acquisition of map data, embodiments of the present application provide a map data transmission method, system, edge server, and storage medium. Below, the map data transmission method provided by the embodiment of the present application is first introduced.

A map data transmission method provided by an embodiment of the present application is applied to a map data transmission system. The system includes an on-board terminal and a roadside terminal, the on-board terminal includes on-board equipment and an on-board communication unit, and the roadside terminal includes a roadside communication unit and an edge The server, the vehicle-mounted communication unit and the roadside communication unit are connected through a communication channel, and data transparent transmission can be realized between the vehicle-mounted communication unit and the roadside communication unit. As shown in Figure 1, the method may include the following steps.

S101, the in-vehicle device sends a map data distribution request to the roadside communication unit through the in-vehicle communication unit.

S102, the roadside communication unit acquires the signal strength of the communication channel with the vehicle-mounted communication unit, and sends the signal strength to the edge server.

S103, the edge server sets the packet size and the data packet sending frequency according to the signal strength.

S104, the edge server divides the map data into multiple data packets according to the packet size.

S105, the edge server transparently transmits each data packet to the in-vehicle device through the roadside communication unit and the in-vehicle communication unit according to the transmission frequency of the data packet.

S106, the in-vehicle device obtains map data based on the received data packets.

Applying the solutions of the embodiments of the present application, the vehicle-mounted device sends a map data distribution request to the roadside communication unit through the vehicle-mounted communication unit to request the roadside terminal to distribute the map data, and after receiving the map data distribution request, the roadside communication unit obtains and communicates with the vehicle. The signal strength of the communication channel between units, and send the obtained signal strength to the edge server. The edge server sets the packet size and data packet sending frequency according to the signal strength, and then divides the map data into multiple pieces of data according to the packet size. packets, and send each data packet to the vehicle subsystem according to the data packet transmission frequency. The transmission distance between the in-vehicle communication unit and the roadside communication unit is relatively short, and since the edge server sets the packet size and data packet transmission frequency based on the signal strength, the impact of the communication quality of the communication channel on the map data transmission is reduced as much as possible. This ensures the efficiency of data packet transmission, so that the in-vehicle device can obtain map data based on each received data packet, thereby improving the efficiency of the vehicle in obtaining map data.

In the embodiments of the present application, the on-board terminal is a general term for the vehicle and the equipment installed on the vehicle that can realize the vehicle automatic driving control function (such as on-board equipment, on-board communication unit), and the roadside terminal is the auxiliary vehicle installed on the side of the road. The general term for driving equipment, the roadside can be composed of traffic lights, control boxes, edge servers, roadside communication units, cameras, radar sensors and other equipment, which can collect real-time vehicle driving conditions, road dynamics, etc.

When the in-vehicle device has a request to obtain map data, such as when navigation is required, the in-vehicle device will send a map data distribution request to the roadside communication unit through the in-vehicle communication unit to request the roadside end to distribute the map data.

In an implementation manner of the embodiment of the present application, S101 may specifically be: when the vehicle on which the vehicle-mounted device is installed drives into the operating design domain of the roadside communication unit, the vehicle-mounted device sends a message to the roadside communication unit through the vehicle-mounted communication unit. Map data distribution request.

When the vehicle enters the ODD (Operational Design Domain) range of the roadside communication unit, in order to ensure the automatic driving of the vehicle, it is necessary to obtain the map data within the ODD range from the roadside end. The in-vehicle equipment will send a map data distribution request to the roadside communication unit through the in-vehicle communication unit to request the roadside end to distribute the map data.

When the vehicle enters the ODD range of the roadside communication unit, roadside sensors (such as cameras, lidar, millimeter-wave radar, etc.) will detect that a vehicle is entering, and the sensor will communicate with the vehicle through the roadside communication unit. The unit sends a reminder message for entering the ODD range to the vehicle-mounted device, and after receiving the reminder message, the vehicle-mounted device sends a map data distribution request to the roadside communication unit through the vehicle-mounted communication unit.

The way in which the in-vehicle device sends a map data distribution request to the roadside communication unit through the in-vehicle communication unit may specifically be: the in-vehicle device sends a BSM (Basic Safety Message, basic safety message) to the roadside communication unit through the in-vehicle communication unit. Add a flag (flag) bit of the map data distribution request. When requesting the roadside end to distribute map data, set the flag bit to a preset flag value (for example, 1). After receiving the BSM, the roadside communication unit will The flag bit is read out, and after identifying the value of the flag bit, if it is a preset flag value, it is determined that the in-vehicle device requests the distribution of map data.

The in-vehicle device can also send a custom request message that satisfies the communication protocol to the roadside communication unit through the in-vehicle communication unit to request the distribution of map data. The message that the in-vehicle device initiates the request may also include vehicle information, such as the vehicle's identification, heading angle, speed, position, and the like.

After receiving the map data distribution request, the roadside communication unit acquires the signal strength of the communication channel between the roadside communication unit and the vehicle-mounted communication unit. A signal strength detector can be set inside the roadside communication unit, and the signal strength detector can detect the signal strength of the communication channel between the roadside communication unit and the vehicle communication unit through the channel detection technology; of course, the roadside communication unit Through the communication establishment process with the on-board communication unit, it is also possible to detect the duration of the data downloaded by the on-board communication unit, the transmission distance between the roadside communication unit and the on-board communication unit, and whether there is obstruction between the roadside communication unit and the on-board communication unit. In general, the longer the transmission distance, the more times the retransmission of lost packets will be, the longer the data download time will be, and the smaller the signal strength will be. The less, the shorter the time to download the data, which increases the signal strength, and reduces the signal strength when there are obstructions. Therefore, further according to these transmission information, the signal strength of the communication channel between the roadside communication unit and the vehicle-mounted communication unit can be calculated. It can be seen from the above analysis that the size of the signal strength can determine the way the communication channel transmits map data. Therefore, the roadside communication unit sends the acquired signal strength to the edge server, and the edge server can set the packet size and data packet transmission according to the signal strength. frequency, so as to make map data distribution as fast, efficient, complete and reliable as possible.

In an implementation manner of the embodiment of the present application, the manner in which the edge server sets the packet size and the data packet sending frequency may specifically be: if the signal strength is less than or equal to the first threshold, set the packet size to be greater than or equal to the first threshold A value of the set value, set the packet sending frequency to a value greater than or equal to the second set value; if the signal strength is greater than the first threshold, less than or equal to the second threshold, set the packet size to be less than the first set value. A fixed value, a value greater than or equal to the third set value, set the data packet sending frequency to a value less than the second set value, greater than or equal to the fourth set value; if the signal strength is greater than the second threshold, set The packet size is a value less than the third set value, and the data packet sending frequency is set to a value less than the fourth set value.

Preferably, the value range of the first threshold is 12-21.5dBm (for example, 15dBm, 19.5dBm, 21dBm), the value range of the second threshold is 21.5-25dBm (for example, 23.5dBm), and the value of the first set value is The range of The value range is 2-5kB (for example, 2kB, 3kB, 4kB, 5kB), and the value range of the fourth setting value is 10-50Hz (for example, 10Hz, 20Hz, 30Hz, 40Hz, 50Hz).

The map data of the edge server is generally obtained from the cloud and stored locally. The map data distribution request sent by the in-vehicle device can carry the identification information of the required map data. After the roadside communication unit receives the map data distribution request, The identification information can be sent to the edge server, and the edge server can perform map version detection according to the identification information, and adapt to the latest version of the map data within the ODD range.

After the edge server sets the packet size and the packet sending frequency, the map data can be divided into multiple packets according to the packet size. Specifically, the map data can be compressed, and then the compressed files can be compressed according to the packet size. It is divided into multiple data packets of the same size. As mentioned above, the size of the data packet can range from 2kB to 8kB. Then, the edge server will transparently transmit each data packet to the in-vehicle device through the roadside communication unit and the in-vehicle communication unit according to the set transmission frequency of the data packet.

After the vehicle-mounted device obtains the complete map data, it can verify and update the data through the vehicle's map data engine, and output the map data to modules such as automatic driving path planning and decision-making, motion control, V2X early warning application, high-precision positioning and visualization, etc. Provide technical support for autonomous driving.

In the current intelligent traffic management system, the roadside communication unit (RSU) and the on-board communication unit (OBU) use short-range communication to communicate, which can realize vehicle identification, electronic toll deduction, and establish unattended vehicle channels. Based on this, in the embodiments of the present application, the short-distance communication between the vehicle-mounted communication unit and the roadside communication unit is used to transmit map data through the private transparent transmission mode between the vehicle-mounted communication unit and the roadside communication unit, so that The in-vehicle terminal can obtain the required map data from the roadside terminal without the need to obtain map data from the cloud through the 4G/5G network, avoiding the influence of network signals and network speed when obtaining data from the cloud.

The communication channel between the in-vehicle communication unit and the roadside communication unit can generally be established by PC5 technology or UWB (Ultra Wide Band, ultra-wideband) technology. Among them, PC5 technology is the third generation of wireless interface in 3GPP (3rd Generation Partnership Project, the third generation of wireless interface). Technical specification) The terminal-to-terminal direct communication technology introduced in the D2D (Device-to-Device, device-to-device) project of Rel-12.

In an implementation manner of the embodiment of the present application, there is a one-to-many correspondence between the edge server and the roadside communication unit. Then S102 may specifically be: the roadside communication unit sends the signal strength to the edge server corresponding to the roadside communication unit.

The edge server is a local server on the roadside, and there are generally multiple. Each edge server is used to store the map data (usually slice data) of the ODD range managed by multiple roadside communication units. There is a one-to-many correspondence between roadside communication units.

In an implementation manner of the embodiment of the present application, before S105, the method may further include: the roadside communication unit sends sub-packet information to the vehicle-mounted communication unit, where the sub-packet information includes the total number of divided data packets and each data packet. the identification information of the package;

After S105, the method may further include: the in-vehicle communication unit receives the packet information, and if it is determined based on the packet information that packet loss occurs in the process of receiving each data packet, sending a data packet re-packet to the roadside communication unit. Send a request to request the RSU to resend the lost data packets until all the data packets are successfully received.

Due to the inevitable loss of data packets in the process of data packet transmission, in order to ensure the integrity of the map data, the roadside communication unit can transparently transmit the data packets to the on-board communication unit. The total number of packets and the sub-packet information of the identification information of each data packet are sent to the on-board communication unit, so that the on-board communication unit can know how many data packets the roadside communication unit will send before starting to receive each data packet, and know each data packet. The identification information of the data packet, in the process of receiving each data packet, the on-board communication unit can judge whether the packet loss has occurred based on the packet information. The side communication unit sends a data packet retransmission request to request the roadside communication unit to retransmit the data packets in which packet loss occurs until all the data packets are successfully received.

In an implementation manner of the embodiment of the present application, after the step of receiving the packet information by the on-board communication unit, the method may further include: the on-board communication unit establishes an empty data packet sequence according to the total number of data packets; The identification information of the data packet is recorded in the data packet sequence in turn;

After S105, the method may further include: the roadside communication unit sends an end message to the vehicle-mounted communication unit;

The in-vehicle communication unit receives the packet information, and if it is determined based on the sub-packet information that packet loss occurs in the process of receiving each data packet, the step of sending a data packet retransmission request to the roadside communication unit may specifically be: After receiving the end message, the communication unit compares the identification information of the received data packet with the identification information recorded in the data packet sequence. The side communication unit sends a data packet retransmission request, wherein the data packet retransmission request carries the identification information of the unreceived data packet.

After receiving the sub-packet information, the on-board communication unit can establish an empty data packet sequence according to the total number of data packets. The number of elements of the data packet sequence is equal to the total number of data packets. Logged into the packet sequence. Correspondingly, after the roadside communication unit transparently transmits each data packet to the vehicle communication unit, the roadside communication unit will also send an end message to the vehicle communication unit. The identification information of the data packet is compared with the identification information recorded in the data packet sequence. If the identification information of the unreceived data packet exists in the data packet sequence, a data packet retransmission request is sent to the roadside communication unit, wherein the data packet The retransmission request carries the identification information of the unreceived data packet. Causes the roadside communication unit to resend the data packets not received by the vehicle-mounted communication unit.

In an implementation manner of the embodiment of the present application, the in-vehicle terminal may be composed of a driver's brain (ie, the above-mentioned in-vehicle device), an in-vehicle communication unit, and an in-vehicle machine. Specifically, the connection methods of each device on the vehicle end may be: the vehicle communication unit is connected to the driving brain, and the driving brain is connected to the vehicle machine; or, the driving brain is included in the vehicle machine, and the vehicle communication unit is connected to the vehicle machine; or, the driving brain and the vehicle communication The unit is included in the car machine. Among them, the driving brain refers to a device with a driving control function on the vehicle, and the vehicle machine refers to a hardware device with a human-computer interaction function on the vehicle (for example, the central control platform of the vehicle).

Through the solution provided by the embodiment of this application, based on the short-distance communication between the V2X roadside terminal and the vehicle terminal, the vehicle-mounted device can obtain map data from the roadside terminal, and it is not necessary to obtain map data from the cloud through the 4G/5G network, avoiding the need for In order to obtain data from the cloud, it will be affected by network signals and network speed, which can save a lot of Uu port traffic, realize low-cost data distribution, and greatly improve the economic benefits of data distribution. In addition, the edge server at the roadside can set the packet size and data packet sending frequency according to the obtained signal strength, and can identify the lost data packets in time, and repeatedly send the lost data packets, so that the roadside The map distribution to the vehicle terminal can achieve the purpose of fast, efficient, complete and reliable, effectively solve the problem of unstable communication between the roadside terminal and the vehicle terminal, and can greatly improve the efficiency of map data distribution. It can be seen from experiments that, by using the solution of the embodiment of the present application, the transmission of ODD map data with a radius of about 300 meters from the roadside end to the vehicle end can be realized within 3 seconds.

The embodiment of the present application further provides a map data transmission method, which is applied to an edge server. As shown in FIG. 2 , the method may include the following steps.

S201: Receive the signal strength sent by the roadside communication unit, where the signal strength is the difference between the roadside communication unit and the vehicle-mounted communication unit acquired by the roadside communication unit after receiving the map data distribution request sent by the vehicle-mounted communication unit The signal strength of the communication channel.

S202, according to the signal strength, set the packet size and the data packet sending frequency.

S203: Divide the map data into multiple data packets according to the packet size.

S204 , transparently transmit each data packet to the in-vehicle device through the roadside communication unit and the vehicle-mounted communication unit according to the transmission frequency of the data packet, so that the in-vehicle device obtains the map data based on each received data packet.

Applying the solution of the embodiment of the present application, after receiving the map data distribution request, the roadside communication unit obtains the signal strength of the communication channel with the vehicle-mounted communication unit, and sends the obtained signal strength to the edge server, and the edge server determines the signal strength according to the signal strength. , set the packet size and packet sending frequency, then divide the map data into multiple packets according to the packet size, and send each packet to the vehicle subsystem according to the packet sending frequency. The transmission distance between the in-vehicle communication unit and the roadside communication unit is relatively short, and since the edge server sets the packet size and data packet transmission frequency based on the signal strength, the impact of the communication quality of the communication channel on the map data transmission is reduced as much as possible. This ensures the efficiency of data packet transmission, so that the in-vehicle device can obtain map data based on each received data packet, thereby improving the efficiency of the vehicle in obtaining map data.

The size of the signal strength can determine the way the communication channel transmits map data. Therefore, the roadside communication unit sends the acquired signal strength to the edge server, and the edge server can set the packet size and data packet sending frequency according to the signal strength, so that the map Data distribution is as fast, efficient, complete and reliable as possible.

In an implementation manner of the embodiment of the present application, the specific method of setting the packet size and the data packet sending frequency may be: if the signal strength is less than or equal to the first threshold, setting the packet size to be greater than or equal to the first setting A value of the value, set the data packet sending frequency to a value greater than or equal to the second set value; if the signal strength is greater than the first threshold, less than or equal to the second threshold, set the packet size to be less than the first set value , a value greater than or equal to the third set value, set the data packet sending frequency to a value less than the second set value and greater than or equal to the fourth set value; if the signal strength is greater than the second threshold, set the packetization The size is a value less than the third set value, and the data packet sending frequency is set to a value less than the fourth set value.

Preferably, the value range of the first threshold is 12-21.5dBm (for example, 15dBm, 19.5dBm, 21dBm), the value range of the second threshold is 21.5-25dBm (for example, 23.5dBm), and the value of the first set value is The range of The value range is 2-5kB (for example, 2kB, 3kB, 4kB, 5kB), and the value range of the fourth setting value is 10-50Hz (for example, 10Hz, 20Hz, 30Hz, 40Hz, 50Hz).

An embodiment of the present application provides a map data transmission system, as shown in FIG. 3 , including: a vehicle terminal and a roadside terminal. The in-vehicle end includes an in-vehicle device 311 and an in-vehicle communication unit 312; the road-side end includes a road-side communication unit 321 and an edge server 322; the in-vehicle communication unit 312 and the road-side communication unit 321 are connected through a communication channel.

The in-vehicle device 311 is used to send a map data distribution request to the roadside communication unit 321 through the in-vehicle communication unit 312;

The roadside communication unit 321 is used to receive the map data distribution request, obtain the signal strength of the communication channel with the vehicle-mounted communication unit 312, and send the signal strength to the edge server 322;

The edge server 322 is used to set the packet size and data packet sending frequency according to the signal strength, divide the map data into multiple data packets according to the packet size, and send the data packets through the roadside communication unit 321 and the vehicle according to the packet sending frequency. The communication unit 312 transparently transmits each data packet to the in-vehicle device 311;

The in-vehicle device 311 is further configured to obtain map data based on the received data packets.

Applying the solutions of the embodiments of the present application, the vehicle-mounted device sends a map data distribution request to the roadside communication unit through the vehicle-mounted communication unit to request the roadside terminal to distribute the map data, and after receiving the map data distribution request, the roadside communication unit obtains and communicates with the vehicle. The signal strength of the communication channel between units, and send the obtained signal strength to the edge server. The edge server sets the packet size and data packet sending frequency according to the signal strength, and then divides the map data into multiple pieces of data according to the packet size. packets, and send each data packet to the vehicle subsystem according to the data packet transmission frequency. The transmission distance between the in-vehicle communication unit and the roadside communication unit is relatively short, and since the edge server sets the packet size and data packet transmission frequency based on the signal strength, the impact of the communication quality of the communication channel on the map data transmission is reduced as much as possible. This ensures the efficiency of data packet transmission, so that the in-vehicle device can obtain map data based on each received data packet, thereby improving the efficiency of the vehicle in obtaining map data.

In the embodiments of the present application, the on-board terminal is a general term for the vehicle and the equipment installed on the vehicle that can realize the vehicle automatic driving control function (such as on-board equipment, on-board communication unit), and the roadside terminal is the auxiliary vehicle installed on the side of the road. The general term for driving equipment, the roadside can be composed of traffic lights, control boxes, edge servers, roadside communication units, cameras, radar sensors and other equipment, which can collect real-time vehicle driving conditions, road dynamics, etc.

When the in-vehicle device 311 has a request to obtain map data, for example, when navigation is required, the in-vehicle device 311 will send a map data distribution request to the roadside communication unit 321 through the in-vehicle communication unit 312 to request the roadside terminal to distribute the map data.

In an implementation manner of the embodiment of the present application, the in-vehicle device 311 may be specifically configured to: when the vehicle on which the in-vehicle device 311 is installed drives into the operating design domain of the roadside communication unit 321 , the in-vehicle device 311 passes the in-vehicle communication unit 312 sends a map data distribution request to the roadside communication unit 321 .

When the vehicle enters the ODD range of the roadside communication unit 321, in order to ensure the automatic driving of the vehicle, it is necessary to obtain map data within the ODD range from the roadside end. Therefore, the in-vehicle device 311 installed on the vehicle will communicate with The unit 312 sends a map data distribution request to the roadside communication unit 321 to request the roadside end to distribute the map data.

The way in which the in-vehicle device 311 sends a map data distribution request to the roadside communication unit 321 through the in-vehicle communication unit 312 may specifically be: the in-vehicle device 311 sends a BSM to the roadside communication unit 321 through the in-vehicle communication unit 312, and a map is added to the BSM The flag bit of the data distribution request, when requesting the roadside end to distribute map data, the flag bit is set to a preset flag value (for example, 1), and the roadside communication unit 321 reads the flag from the BSM after receiving the BSM. After identifying the value of the flag bit, if it is a preset flag value, it is determined that the in-vehicle device 311 requests to distribute map data.

After receiving the map data distribution request, the roadside communication unit 321 will acquire the signal strength of the communication channel between the roadside communication unit 321 and the vehicle-mounted communication unit 312, and then send the acquired signal strength to the edge server 322, and the edge server 322 can set the packet size and data packet sending frequency according to the signal strength, so that the map data distribution can be as fast, efficient, complete and reliable as possible.

In an implementation manner of the embodiment of the present application, when the edge server 322 is used to set the packet size and the data packet sending frequency, it can be specifically used to: if the signal strength is less than or equal to the first threshold, set the packet size to be A value greater than or equal to the first set value, set the packet sending frequency to a value greater than or equal to the second set value; if the signal strength is greater than the first threshold, less than or equal to the second threshold, set the packet size To be a value less than the first set value and greater than or equal to the third set value, set the data packet sending frequency to a value less than the second set value and greater than or equal to the fourth set value; if the signal strength is greater than the first set value If there are two thresholds, the packet size is set to a value smaller than the third set value, and the data packet transmission frequency is set to a value less than the fourth set value.

Preferably, the value range of the first threshold is 12-21.5dBm (for example, 15dBm, 19.5dBm, 21dBm), the value range of the second threshold is 21.5-25dBm (for example, 23.5dBm), and the value of the first set value is The range of The value range is 2-5kB (for example, 2kB, 3kB, 4kB, 5kB), and the value range of the fourth setting value is 10-50Hz (for example, 10Hz, 20Hz, 30Hz, 40Hz, 50Hz).

After the edge server 322 sets the packet size and the packet sending frequency, the map data can be divided into multiple packets according to the packet size. Specifically, the map data can be compressed and then compressed according to the packet size. The file is divided into multiple data packets of the same size. As mentioned above, the size of the data packet can range from 2kB to 8kB. Then, the edge server 322 will transparently transmit each data packet to the in-vehicle device through the roadside communication unit 321 and the in-vehicle communication unit 312 according to the set data packet sending frequency, that is, the edge server 322 sends the data packet to the roadside communication unit 321, The data packet is then transparently transmitted to the vehicle-mounted communication unit 312 by the road-side communication unit 321 .

After the vehicle-mounted device 311 obtains the complete map data, it can verify and update the data through the vehicle's map data engine, and output the map data to modules such as automatic driving path planning and decision-making, motion control, V2X early warning application, high-precision positioning and visualization, etc. , providing technical support for autonomous driving.

The communication channel between the in-vehicle communication unit 312 and the roadside communication unit 321 can generally be established using the PC5 technology or the UWB technology, wherein the PC5 technology is a terminal-to-terminal direct communication technology introduced in the D2D project of 3GPP Rel-12.

In an implementation manner of the embodiment of the present application, there is a one-to-many correspondence between the edge server and the roadside communication unit. Then, when the roadside communication unit is used to send the signal strength to the edge server, it can be specifically used for: the roadside communication unit sends the signal strength to the edge server corresponding to the roadside communication unit.

The edge server is a local server on the roadside, and there are generally multiple. Each edge server is used to store the map data (usually slice data) of the ODD range managed by multiple roadside communication units. There is a one-to-many correspondence between roadside communication units.

In an implementation manner of the embodiment of the present application, the roadside communication unit may also be used to: send subcontracting information to the vehicle-mounted communication unit, where the subcontracting information includes the total number of divided data packets and the identification information of each data packet;

The in-vehicle communication unit can also be used to: receive sub-packet information, and if it is determined based on the sub-packet information that packet loss occurs in the process of receiving each data packet, send a data packet retransmission request to the roadside communication unit to request The RSU resends the lost packets until all packets are successfully received.

Due to the inevitable loss of data packets during data packet transmission, in order to ensure the integrity of the map data, the roadside communication unit 321 can transparently transmit the data packets to the on-board communication unit 312. The total number of data packets and the sub-packet information of the identification information of each data packet are sent to the in-vehicle communication unit 312, so that the in-vehicle communication unit 312 can know how many data packets the roadside communication unit 321 will send before starting to receive each data packet. , and know the identification information of each data packet, then in the process of receiving each data packet, the on-board communication unit 312 can judge whether the packet loss has occurred based on the packet information. In this case, a data packet retransmission request may be sent to the roadside communication unit 321 to request the roadside communication unit 321 to resend the data packets in which packet loss occurred until all data packets are successfully received.

In an implementation of the embodiment of the present application, the on-board communication unit may also be used to: establish an empty data packet sequence according to the total number of data packets; the on-board communication unit records the identification information of each data packet into the data packet sequence in turn ;

The roadside communication unit may also be used to: send an end message to the vehicle-mounted communication unit;

When the in-vehicle communication unit is used to receive sub-packet information, if it is determined based on the sub-packet information that data packet loss occurs during the process of receiving each data packet, when sending a data packet retransmission request to the roadside communication unit, it can be specifically In: after receiving the end message, compare the identification information of the received data packet with the identification information recorded in the data packet sequence, if the identification information of the unreceived data packet exists in the data packet sequence, send the The side communication unit sends a data packet retransmission request, wherein the data packet retransmission request carries the identification information of the unreceived data packet.

After receiving the sub-packet information, the on-board communication unit 312 can establish an empty data packet sequence according to the total number of data packets, and the number of elements of the data packet sequence is equal to the total number of data packets. , which are sequentially recorded in the packet sequence. Correspondingly, after the roadside communication unit 321 transparently transmits each data packet to the onboard communication unit 312, the roadside communication unit 321 will also send an end message to the onboard communication unit 312. In this way, after the onboard communication unit 312 receives the end message, Compare the identification information of the received data packet with the identification information recorded in the data packet sequence, if the identification information of the unreceived data packet exists in the data packet sequence, then send the data packet retransmission to the roadside communication unit 321 request, wherein the data packet retransmission request carries the identification information of the data packet that has not been received. The roadside communication unit 321 is caused to resend the data packets not received by the in-vehicle communication unit 312 .

In an implementation manner of the embodiment of the present application, the in-vehicle terminal may be composed of a driver's brain (ie, the above-mentioned in-vehicle device), an in-vehicle communication unit, and an in-vehicle machine. Specifically, the connection methods of each device on the vehicle end may be: the vehicle communication unit is connected to the driving brain, and the driving brain is connected to the vehicle machine; or, the driving brain is included in the vehicle machine, and the vehicle communication unit is connected to the vehicle machine; or, the driving brain and the vehicle communication The unit is included in the car machine. Among them, the driving brain refers to a device with a driving control function on the vehicle, and the vehicle machine refers to a hardware device with a human-computer interaction function on the vehicle (for example, the central control platform of the vehicle).

For ease of understanding, the map data transmission method provided by the embodiment of the present application is introduced below with reference to a specific system example.

As shown in FIG. 4 , which is a schematic diagram of a specific example of the embodiment of the present application, before the map data is issued, it is necessary to establish a vehicle-connected system with a vehicle-road-cloud integrated V2X environment according to the needs of the scene, which is divided into cloud platform sub-systems. systems, on-board subsystems and roadside subsystems.

Data transmission is carried out between the vehicle subsystem and the roadside subsystem through the PC5 interface, and the main function is to transmit map data. The vehicle subsystem connects data through the 4G of the Uu port and the cloud platform subsystem, and obtains dynamic traffic data from the cloud platform subsystem through the Uu port. The roadside subsystem connects data with the cloud platform subsystem through optical fiber/wired Ethernet, and obtains map data and dynamic traffic data from the cloud platform subsystem. The cloud platform subsystem can also exchange data with third-party platforms through optical/wired Ethernet.

The internal structure of each subsystem of the IoV system is shown in Figure 5. The roadside subsystem is mainly composed of RSU (that is, the above-mentioned roadside communication unit), edge server and roadside sensing equipment, and is connected with the cloud platform subsystem through the optical switch. Data interaction. The in-vehicle subsystem is mainly composed of OBU (that is, the above-mentioned in-vehicle communication unit), driving brain (that is, the above-mentioned in-vehicle equipment), and in-vehicle machine (HMI and Pad in-vehicle visualization module in Figure 5). The cloud platform subsystem mainly includes database and cloud platform server. In the temporary test field stage, the cloud platform server is mainly V2X server, which has the function of digital twin, and exchanges data with the roadside subsystem through the optical fiber switch.

Roadside perception equipment includes cameras, lidars, millimeter-wave radars, and edge computing equipment. By deploying cameras, lidars, millimeter-wave radars, and other equipment on site, the original information perception of the traffic system is realized, and then the data is processed through edge computing capabilities. Processed to form local perception and statistical results to support roadside smart applications.

The internal interaction process of the car-connected system is shown in Figure 6. The third-party platform interacts with the cloud platform subsystem. The data storage module of the cloud platform subsystem stores the active map data, and the automatic driving data production module is based on the source map data and dynamic data. Traffic data, get the AD map data production library, and then use the online compilation module to compile and publish the data to obtain the AD map data publishing library, and then the data distribution service module through the data preparation, data query and data extraction process, through the data publishing unit. After the roadside subsystem receives the map data information, the edge server checks the version polling. If it is found that the cloud platform subsystem has updated the map data, it will send the map data to the cloud platform. The subsystem sends a version update request message, obtains updated map data from the cloud platform subsystem, and stores it in the local AD map database. And the edge server can form data such as local perception and statistical results according to the data collected by the roadside perception device, which is used to support roadside smart applications.

When the vehicle with the OBU installed enters the electronic fence of the RSU, the driving brain sends a request message to the RSU through the PC5 channel via the OBU, and the RSU transmits the request message to the edge server. The data distribution service module in the edge server receives the request message and passes Data query and data release, return map data to RSU, enter transparent transmission mode between RSU and OBU, and RSU sends map data to OBU. In addition, the router in the vehicle subsystem can also request dynamic traffic data from the cloud platform server through the Uu interface. The router and the OBU respectively send the obtained data to the driver's brain, and the driver's brain operates through data fusion and map data engine. In-vehicle applications such as visualization, V2X early warning applications, high-precision positioning, path planning and decision-making, and motion control.

The specific process of roadside high-precision map data distribution is shown in Figure 7. When the vehicle enters the electronic fence of the RSU, the driving brain generates a request message. The request message contains vehicle information, such as vehicle identification information, heading angle, speed, Location, etc.; the request message is transparently transmitted to the RSU through the OBU, and the RSU transmits the request message to the edge server, the edge server performs data query, and returns the map block number and quantity to the OBU through the RSU, and the OBU sends the map block number and quantity to the OBU. It is passed to the driving brain, where the source of data query by the edge server includes the map data sent by the cloud and the data obtained by the roadside perception device through data backhaul and data construction by the edge server. The map data sent by the cloud is mainly determined by the ODD range. , the steps of AD map data release are obtained; the driving brain requests the corresponding specific map block from the RSU through the OBU, and after receiving the specific request, the edge device sets the packet size and data packet sending frequency according to the signal strength; according to the packet size, Divide the map data into multiple data packets of the same size, and then start the data download service. The data download service is to transparently transmit each data packet to the OBU through the RSU according to the frequency of data packet transmission, and the driving brain receives each data packet from the OBU, and then Perform data verification and decompression operations, then start the data update service, reuse Uu port data to update, based on the updated map data, perform tracing automatic driving, avoid driving/stop, and handle abnormal situations if encountered. Or perform a breakpoint retransmission operation.

The process of transparently transmitting data packets between RSU and OBU is shown in Figure 8, including the following steps:

1. The OBU requests to download the map data of a specific map block, and sends a REQ (request message) to the RSU.

2. After the RSU receives the REQ, it sends the basic information FILEMSG of the map information corresponding to the applied map block to the OBU. If the ACK (feedback message) is not received in k seconds, it will re-send, and exit after re-sending at most 2 times. FILEMSG includes file size, total number of sub-packages, etc.

3. After receiving the FILEMSG, the OBU creates a new empty file for receiving data packets, and creates a packet loss sequence according to the total number of packets to confirm the number of lost packets, and returns ACK_FILEMSG to the RSU.

4. RSU sends all data packets of map data to OBU at one time, and sends a FILEEND to indicate that it has been sent.

5. After the OBU receives FILEEND, it checks the packet loss sequence to see if there are any unreceived data packets. If not, it returns ACK_FILEEND to end the communication or send a new REQ. If there are unreceived data packets, send ACK_RESEND to request retransmission of the corresponding data packets.

6. RSU sends RESEND with the corresponding data packet according to the data packet number requested by ACK_RESEND. If the OBU times out and does not receive RESEND, it will retransmit at most 2 times.

7. After receiving the RESEND, the OBU checks the packet loss sequence again. If there is a packet loss, it sends ACK_RESEND. If there is no packet loss, it sends ACK_END to end.

8. The RSU receives ACD_END and ends the transmission.

The embodiment of the present application also provides an edge server, as shown in FIG. 9 , including a processor 901 and a memory 902 , wherein the memory 902 is used to store computer programs; In the case of a computer program, the above-mentioned map data transmission method applied to an edge server is realized.

The above-mentioned memory may include RAM (Random Access Memory, random access memory), and may also include NVM (Non-volatile Memory, non-volatile memory), such as at least one disk memory. Optionally, the memory may also be at least one storage device located far away from the above-mentioned processor.

The above-mentioned processors can be general-purpose processors, including CPU (Central Processing Unit, central processing unit), NP (Network Processor, network processor), etc.; can also be DSP (Digital Signal Processing, digital signal processor), ASIC (Application Specific Integrated Circuit), FPGA (Field-Programmable Gate Array, Field Programmable Gate Array) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

In this embodiment, by reading the computer program stored in the memory, and by running the computer program, the above-mentioned processor can realize: after the roadside communication unit receives the map data distribution request, it can obtain the information of the communication channel with the vehicle-mounted communication unit. Signal strength, and send the obtained signal strength to the edge server. The edge server sets the packet size and packet sending frequency according to the signal strength, and then divides the map data into multiple packets according to the packet size and sends them according to the packet size. The frequency sends each data packet to the onboard subsystem. The transmission distance between the in-vehicle communication unit and the roadside communication unit is relatively short, and since the edge server sets the packet size and data packet transmission frequency based on the signal strength, the impact of the communication quality of the communication channel on the map data transmission is reduced as much as possible. This ensures the efficiency of data packet transmission, so that the in-vehicle device can obtain map data based on each received data packet, thereby improving the efficiency of the vehicle in obtaining map data.

In addition, an embodiment of the present invention provides a storage medium, where a computer program is stored in the storage medium, and when the computer program is executed by a processor, the above-mentioned map data transmission method applied to an edge server is implemented.

In this embodiment, the computer-readable storage medium stores a computer program that executes the map data transmission method applied to the edge server provided by the embodiment of the present invention at runtime, so it can be realized that the roadside communication unit receives the map data distribution request Then, obtain the signal strength of the communication channel with the vehicle communication unit, and send the obtained signal strength to the edge server. The edge server sets the packet size and data packet sending frequency according to the signal strength, and then maps the map according to the packet size The data is divided into multiple data packets, and each data packet is sent to the vehicle subsystem according to the data packet transmission frequency. The transmission distance between the in-vehicle communication unit and the roadside communication unit is relatively short, and since the edge server sets the packet size and data packet transmission frequency based on the signal strength, the impact of the communication quality of the communication channel on the map data transmission is reduced as much as possible. This ensures the efficiency of data packet transmission, so that the in-vehicle device can obtain map data based on each received data packet, thereby improving the efficiency of the vehicle in obtaining map data.

In yet another embodiment provided by the embodiments of the present invention, there is also a computer program product including instructions, which, when running on a computer, cause the computer to execute the above-mentioned map data transmission method applied to an edge server.

In the above-mentioned embodiments, it may be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented in software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present invention are generated. The computer may be a general purpose computer, special purpose computer, computer network, or other programmable device. The computer instructions may be stored in or transmitted from one computer readable storage medium to another computer readable storage medium, for example, the computer instructions may be downloaded from a website site, computer, server or data center Transmission to another website site, computer, server or data center by wire (such as coaxial cable, optical fiber, DSL (Digital Subscriber Line, digital subscriber line)) or wireless (such as infrared, wireless, microwave, etc.). The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that includes an integration of one or more available media. The usable medium may be a magnetic medium (such as a floppy disk, a hard disk, a magnetic tape), an optical medium (such as a DVD (Digital Versatile Disc, digital versatile disc)), or a semiconductor medium (such as an SSD (Solid State Disk, solid-state drive)), etc. .

For the embodiments of the edge server, the storage medium and the computer program product, since the content of the method involved is basically similar to the foregoing embodiment of the map data transmission method applied to the edge server, the description is relatively simple, and for related details, refer to the method Part of the description of the embodiment is sufficient.

It should be noted that, in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any relationship between these entities or operations. any such actual relationship or sequence exists. Moreover, the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a process, method, article or device that includes a list of elements includes not only those elements, but also includes not explicitly listed or other elements inherent to such a process, method, article or apparatus. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in a process, method, article or apparatus that includes the element.

Each embodiment in this specification is described in a related manner, and the same and similar parts between the various embodiments may be referred to each other, and each embodiment focuses on the differences from other embodiments.

The above descriptions are only preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application are included in the protection scope of this application.

Claims (14)

1. A method for transmitting map data, comprising:

   The in-vehicle device sends a map data distribution request to the roadside communication unit through the in-vehicle communication unit;

   The roadside communication unit receives the map data distribution request, acquires the signal strength of the communication channel with the vehicle-mounted communication unit, and sends the signal strength to the edge server;

   The edge server sets the packet size and the data packet sending frequency according to the signal strength, divides the map data into multiple data packets according to the packet size, and sends the data packets through the road according to the packet sending frequency. The side communication unit and the in-vehicle communication unit transparently transmit each data packet to the in-vehicle device;

   The in-vehicle device obtains the map data based on the received data packets.
2. The method according to claim 1, wherein the step of the on-board equipment sending a map data distribution request to the roadside communication unit through the on-board communication unit comprises:

   When the vehicle on which the in-vehicle device is installed drives into the operational design domain of the roadside communication unit, the in-vehicle device sends a map data distribution request to the roadside communication unit through the in-vehicle communication unit.
3. The method according to claim 1 or 2, wherein the step of the on-board equipment sending a map data distribution request to the roadside communication unit through the on-board communication unit comprises:

   The in-vehicle device sends a basic safety message to the roadside communication unit through the in-vehicle communication unit, wherein the preset flag bit in the basic safety message is set as a flag value representing a request for the edge server to distribute map data;

   The step of receiving the map data distribution request by the roadside communication unit includes:

   The roadside communication unit receives the basic safety message, and identifies the preset flag bit in the basic safety message. If it is identified that the preset flag bit is set to represent a request for the edge server to distribute map data If the flag value is set, it is determined that a map data distribution request is received.
4. The method according to claim 1, wherein there is a one-to-many correspondence between the edge server and the roadside communication unit;

   The step of the roadside communication unit sending the signal strength to the edge server includes:

   The roadside communication unit sends the signal strength to the edge server corresponding to the roadside communication unit.
5. The method according to claim 1, wherein the step of setting the packet size and the data packet sending frequency by the edge server according to the signal strength comprises:

   If the signal strength is less than or equal to the first threshold, the edge server sets the packet size to a value greater than or equal to the first set value, and sets the data packet sending frequency to a value greater than or equal to the second set value value;

   If the signal strength is greater than the first threshold and less than or equal to the second threshold, the edge server sets the packet size to a value that is less than the first set value and greater than or equal to a third set value, Setting the data packet sending frequency to a value less than the second set value and greater than or equal to the fourth set value;

   If the signal strength is greater than the second threshold, the edge server sets the packet size to a value less than the third set value, and sets the data packet sending frequency to a value less than the fourth set value value.
6. The method according to claim 5, wherein the value range of the first threshold is 12-21.5dBm, the value range of the second threshold is 21.5-25dBm, and the first set value is in the range of 21.5-25dBm. The value range is 5-8kB, the value range of the second set value is 50-100Hz, the value range of the third set value is 2-5kB, the value range of the fourth set value is The range is 10-50Hz.
7. The method according to claim 1, wherein the edge server transparently transmits each data packet to the in-vehicle device through the roadside communication unit and the in-vehicle communication unit according to the data packet transmission frequency Before the step, the method further includes:

   The roadside communication unit sends sub-packet information to the vehicle-mounted communication unit, wherein the sub-packet information includes the total number of divided data packets and the identification information of each data packet;

   The method also includes:

   The in-vehicle communication unit receives the packet information, and if it is determined based on the packet information that packet loss occurs in the process of receiving each data packet, it sends a data packet retransmission request to the roadside communication unit. , so as to request the roadside communication unit to resend the data packets that have lost packets until all the data packets are successfully received.
8. The method according to claim 7, characterized in that, after the step of receiving the packet information by the vehicle-mounted communication unit, the method further comprises:

   The in-vehicle communication unit establishes an empty data packet sequence according to the total number of data packets;

   The in-vehicle communication unit records the identification information of each data packet into the data packet sequence in sequence;

   After the edge server transparently transmits each data packet to the in-vehicle device through the roadside communication unit and the in-vehicle communication unit according to the transmission frequency of the data packet, the method further includes:

   The roadside communication unit sends an end message to the vehicle-mounted communication unit;

   The in-vehicle communication unit receives the packet information, and if it is determined based on the packet information that packet loss occurs in the process of receiving each data packet, it sends a data packet retransmission request to the roadside communication unit. steps, including:

   After receiving the end message, the on-board communication unit compares the identification information of the received data packet with the identification information recorded in the data packet sequence. If the identification information of the data packet is obtained, a data packet retransmission request is sent to the roadside communication unit, wherein the data packet retransmission request carries the identification information of the unreceived data packet.
9. A method for transmitting map data, comprising:

   The edge server receives the signal strength sent by the roadside communication unit, where the signal strength is the relationship between the roadside communication unit and the roadside communication unit obtained by the roadside communication unit after receiving the map data distribution request sent by the vehicle communication unit. the signal strength of the communication channel between the onboard communication units;

   The edge server sets the packet size and the data packet sending frequency according to the signal strength;

   The edge server divides the map data into multiple data packets according to the packet size;

   The edge server transparently transmits each data packet to the in-vehicle device through the roadside communication unit and the in-vehicle communication unit according to the transmission frequency of the data packet, so that the in-vehicle device obtains the data packet based on the received data packet. the map data.
10. The method according to claim 9, wherein the step of setting the packet size and the data packet sending frequency according to the signal strength comprises:

    If the signal strength is less than or equal to the first threshold, set the packet size to a value greater than or equal to the first set value, and set the packet transmission frequency to a value greater than or equal to the second set value;

    If the signal strength is greater than the first threshold and less than or equal to the second threshold, set the packet size to a value smaller than the first set value and greater than or equal to the third set value, and set the packet transmission The frequency is a value less than the second set value and greater than or equal to the fourth set value;

    If the signal strength is greater than the second threshold, the packet size is set to a value smaller than the third set value, and the data packet transmission frequency is set to a value less than the fourth set value.
11. The method according to claim 10, wherein the value range of the first threshold is 12-21.5dBm, the value range of the second threshold is 21.5-25dBm, and the first set value is in the range of 21.5-25dBm. The value range is 5-8kB, the value range of the second set value is 50-100Hz, the value range of the third set value is 2-5kB, the value range of the fourth set value is The range is 10-50Hz.
12. A map data transmission system, comprising: a vehicle-mounted terminal and a roadside terminal; the vehicle-mounted terminal includes vehicle-mounted equipment and a vehicle-mounted communication unit; the roadside terminal includes a roadside communication unit and an edge server; the vehicle-mounted communication unit The unit is connected with the roadside communication unit through a communication channel;

    the in-vehicle device, configured to send a map data distribution request to the roadside communication unit through the in-vehicle communication unit;

    the roadside communication unit, configured to receive the map data distribution request, obtain the signal strength of the communication channel with the vehicle-mounted communication unit, and send the signal strength to the edge server;

    The edge server is configured to set the packet size and the data packet sending frequency according to the signal strength, divide the map data into multiple data packets according to the packet size, and send the data packets through the The roadside communication unit and the vehicle-mounted communication unit transparently transmit each data packet to the vehicle-mounted device;

    The in-vehicle device is further configured to obtain the map data based on the received data packets.
13. An edge server, comprising a processor and a memory;

    the memory for storing computer programs;

    The processor is configured to implement the method according to any one of claims 9-11 when executing the computer program stored in the memory.
14. A storage medium, characterized in that a computer program is stored in the storage medium, and when the computer program is executed by a processor, the method according to any one of claims 9-11 is implemented.

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