EP4066519A1

EP4066519A1 - Method and device for transmitting data for a vehicle

Info

Publication number: EP4066519A1
Application number: EP20803217.7A
Authority: EP
Inventors: Sharique Khan; Alexandre Fromion
Original assignee: PSA Automobiles SA
Current assignee: Stellantis Auto SAS
Priority date: 2019-11-25
Filing date: 2020-10-16
Publication date: 2022-10-05
Also published as: FR3103661B1; WO2021105571A1; FR3103661A1; US20220394440A1; CN114731495A

Abstract

The invention relates to a method and a device for transmitting data for a vehicle, in particular in a V2X communication network. For this purpose, a data frame (2) is transmitted in a vehicle-to-everything (V2X) communication mode. The frame (2) advantageously comprises a series (200) of a plurality of identical and consecutive data packets (21 to 24) in the data frame, each packet (21 to 24) comprising the same set of identical data.

Description

DESCRIPTION

Title: Vehicle data transmission method and device

Technical area

The invention relates to methods and devices for transmitting data for vehicles, in particular of the automobile type. The invention relates more particularly to a method and a device for transmitting data according to a vehicle-to-everything type of communication mode, known as V2X, in particular for the transmission of emergency or alert messages.

Technological background

Contemporary vehicles have on-board communications systems that allow vehicles to exchange information with each other or with their environment, including information associated with warning or emergency messages to warn of a danger, for example.

Thus, new information and communication technologies applied to the field of transport have appeared, such as the ITS G5 (standing for “Intelligent Transportation System G5” or in French for “Système de transport intelligent G5”) in Europe or DSRC (from English "Dedicated Short Range Communications" or in French "Communications dedicated to short range") in the United States of America which are both based on the standard IEEE 802.11 p or the technology based on cellular networks named C-V2X (from the English "Cellular - Vehicle to Everything" or in French "Cellulaire - Vehicle to everything") which is based on 4G based on LTE (from the English "Long Term Evolution" or in French “Long term evolution”) and soon 5G.

As vehicles are by definition mobile, data transmission is sometimes accompanied by errors and / or loss of information, for example due to losses temporary connections. These transmission problems can prove to be particularly damaging when the data transmitted by a vehicle relate to an alert or emergency message to warn road users of an imminent danger, for example.

Summary of the invention

An object of the present invention is to secure the transmission of data in a vehicle-to-everything type communication system, called V2X.

Another object of the invention is to improve the reliability of data transmission by a vehicle, in particular for data relating to an emergency or distress.

According to a first aspect, the invention relates to a method of transmitting data for a vehicle, the method comprising a transmission of a data frame according to a vehicle-to-all communication mode, called V2X, the frame comprising a series of several identical packets. and consecutive in the frame.

According to a variant, a different error detection code is associated with each of the packets in the series.

According to another variant, a different error correction code is associated with each of the packets in the series.

According to an additional variant, each packet of the series comprises the same set of identical data representative of an emergency message or of an alert message.

According to an additional variant, the data of the data set correspond to message data of the CAM or DENM type.

According to yet another variant, a transmission time interval is associated with each packet of the series, the series forming a group of transmission time intervals.

According to another variant, a number of identical packets included in said series is determined from a transmission performance indicator. In particular, in one embodiment, the performance indicator comprises at least one of the elements among:

- a packet error rate;

- a frame error rate;

- an acknowledgment number;

- a number of non-acknowledgments.

According to a second aspect, the invention relates to a vehicle data transmission device, the device comprising a memory associated with a processor configured for implementing the steps of the method according to the first aspect of the invention.

According to a third aspect, the invention relates to a vehicle, for example of the automobile type, comprising a device as described above according to the second aspect of the invention.

According to a fourth aspect, the invention relates to a computer program which comprises instructions adapted for the execution of the steps of the method according to the first aspect of the invention, this in particular when the computer program is executed by at least one. processor.

Such a computer program can use any programming language, and be in the form of a source code, an object code, or an intermediate code between a source code and an object code, such as in a partially compiled form, or in any other desirable form.

According to a fifth aspect, the invention relates to a recording medium readable by a computer on which is recorded a computer program comprising instructions for carrying out the steps of the method according to the first aspect of the invention.

On the one hand, the recording medium can be any entity or device capable of storing the program. For example, the medium may comprise a storage means, such as a ROM memory, a CD-ROM or a ROM memory of the type. microelectronic circuit, or a magnetic recording medium or a hard disk.

On the other hand, this recording medium can also be a transmissible medium such as an electrical or optical signal, such a signal being able to be conveyed via an electrical or optical cable, by conventional or hertzian radio or by self-directed laser beam or by other ways. The computer program according to the invention can in particular be downloaded over an Internet-type network.

Alternatively, the recording medium can be an integrated circuit in which the computer program is incorporated, the integrated circuit being adapted to execute or to be used in the execution of the method in question.

Brief description of the figures

Other characteristics and advantages of the invention will emerge from the description of the non-limiting embodiments of the invention below, with reference to Figures 1 to 4 attached, in which:

[Fig. 1] schematically illustrates a V2X communication environment, according to a particular embodiment of the present invention;

[Fig. 2] schematically illustrates the structure of a data frame transmitted by a vehicle of the communication environment of Figure 1, according to a particular embodiment of the present invention;

[Fig. 3] schematically illustrates a device configured to transmit the data frame of FIG. 2, according to a particular embodiment of the present invention;

[Fig. 4] illustrates a flowchart of the various steps of a data transmission method for a vehicle in the environment of FIG. 1, according to a particular embodiment of the present invention.

Description of the embodiments A method and a device for transmitting data for a vehicle, in particular in a V2X type communication network, will now be described in what follows with reference jointly to FIGS. 1 to 4.

According to a particular and non-limiting example of an embodiment of the invention, a data transmission method, in particular in a V2X type communication network, comprises the transmission of one or more data frames according to a vehicle communication mode to any vehicle. , says V2X. Each frame advantageously comprises a series of several identical and consecutive data packets in the data frame, each packet comprising the same set of identical data.

The concatenation of several identical packets in the same data frame transmitted to one or more recipients makes it possible to improve the security of the transmission, that is to say to increase the probability that the data contained in the packets are actually received by the recipient (s).

[Fig. 1] schematically illustrates a communication environment 1 in a V2X type communication network (standing for “Vehicle-to-everything” in French), according to a particular and non-limiting example of embodiment of the present invention.

FIG. 1 illustrates a first vehicle 10 traveling in a road environment. The first vehicle 10 advantageously takes on board a communication device for transmitting and receiving data intended for another communication device, for example a communication device on board a second vehicle 11 or carried by a pedestrian 12 or by a cyclist 13. Each communication device can be likened to a node of a network, for example an ad hoc wireless network.

The first vehicle 10 transmits information or data to the second vehicle, the pedestrian 12 and / or the cyclist 13 using a vehicle-to-all communication system, called V2X, for example based on the 3GPP LTE-V or IEEE standards. 802.11p from ITS G5. In such a V2X communication system, each vehicle embeds a node to allow communication from vehicle to vehicle V2V (from the English "vehicle-to-vehicle"), from vehicle to infrastructure V2I (from the English "vehicle-to-infrastructure") and / or from V2P (vehicle-to-pedestrian) vehicle, pedestrians (or cyclists) being equipped with mobile devices (for example a smart phone (from the English “Smartphone”)) configured to communicate with the vehicles.

An ad hoc wireless network (also called WANET (English "Wireless Ad Hoc Network") or MANET (English "Mobile Ad Hoc Network")) is a decentralized wireless network. Unlike a centralized network which relies on an existing infrastructure comprising, for example, routers or access points linked together by a wired or wireless infrastructure, the ad hoc wireless network consists of nodes which each participate in the network. data routing by retransmitting the data from one node to another, from the sender to the recipient, depending on the connectivity of the network and the routing algorithm implemented. The ad hoc wireless network advantageously corresponds to an ad hoc vehicular network (or VANET, standing for “Vehicular Ad hoc NETwork”) or to an intelligent ad hoc vehicular network (or InVANET, for “Intelligent Vehicle Ad hoc”). NETwork ”), also called“ GeoNetworking ”network. In such a network, 2 or more vehicles each carrying a node can communicate with each other within the framework of a V2V vehicle-to-vehicle communication ("vehicle-to-vehicle"); each vehicle can communicate with the infrastructure set up as part of a vehicle-to-infrastructure communication V2I (from English "vehicle-to-infrastructure"); each vehicle can communicate with one or more pedestrians equipped with mobile devices (for example a smart phone (standing for “Smartphone”)) as part of a V2P vehicle-to-pedestrian communication (standing for “vehicle-to-”). pedestrian ”).

The ad hoc wireless network comprises transmission relays 101, 102 corresponding for example to one or more UBR (“Roadside Unit”) 101, 102, each corresponding to a node of the network, in addition to the nodes equipping the vehicles or pedestrians. According to one variant, the transmission relays 101, 102 correspond to relay antennas of a cellular network, for example a so-called 4G or 5G cellular network. According to yet another variant, the ad hoc wireless network comprises one or more UBRs and one or more relay antennas of a cellular network, in addition to the nodes equipping vehicles or pedestrians. According to this variant, the node 101 corresponds for example to a UBR and the node 102 to a relay antenna.

The relays 101 and 102 are advantageously connected to one or more remote servers or to the “cloud” 100 (or in French “cloud”) via a wired and / or wireless connection. The relays 101 and 102 can thus act as relays between the “cloud” 100 and the first vehicle 10, the second vehicle 11, the pedestrian 12 and / or the cyclist 13.

According to an alternative embodiment, the first vehicle 10 transmits data to the second vehicle 11, the pedestrian 12 and / or the cyclist 13 according to a direct communication mode, that is to say without going through the network infrastructure. (including relays 101 and 102). For example, a direct communication mode conforms to:

- ITS G5 in Europe or DSRC (from English "Dedicated Short Range Communications" or in French "Communications dedicated to short range") in the United States of America, both of which are based on the IEEE 802.11p standard; or

- LTE-V Mode 4 (from the English “Long-Term Evolution - Vehicle Mode 4” or in French “Long-Term Evolution - Vehicle Mode 4”) which allows V2V communications, also called “sidelink” communications (or in French "lateral link")) based on a direct LTE communication interface called PC5; such a technology is described for example in the article entitled "Analytical Models of the Performance of C-V2X Mode 4 Vehicular Communications", written by Manuel Gonzalez-Martin, Miguel Sépulcre, Rafael Molina-Masegosa and Javier Gozalvez, and published in 2018 .

In a first operation, a data frame comprising a series of identical data packets is formed by the first vehicle 10. This data frame corresponds for example to the data frame described with reference to FIG. 2. The data packets are said to be identical in that the payload data that each of these packets carries are identical. The number of identical packets in the series is for example between 2 and 10, for example equal to 2, 3, 4, 5 packs. Each packet of the series advantageously comprises data representative of an emergency and / or alert and / or distress message, these data making it possible to warn the recipient (s) of the data frame of a danger or an emergency. . These data correspond, for example, to data of one or more DENM type messages (standing for “Decentralized Environmental Notification Message” or in French “Message de notification environnement decentralisé”) as defined in the technical specification ETSI TS 102 637. -3 v1.1.1 of September 2010. According to another example, these data correspond for example to data of one or more messages of the CAM type (from the English "Cooperative Awareness Message" or in French "Cooperative Warning Message ") As defined in the technical specification ETSI TS 102 637-2 v1.2.1 of March 2011.

The data packets are grouped together so as to be consecutive in the data frame, that is to say that the data packets of the series are for example grouped together in a transmission burst. ) or in a grouping of transmission time intervals (from the English "Transmission Time Interval bundling", called "TTI bundling" or "TTI grouping" in French), a transmission time interval, called TTI, (by example equal to 40 ms) being associated or allocated to each data packet in the series.

The number of packets in the series corresponds for example to a default parameter, this number being fixed whatever the situation.

According to one variant, the number of packets in the series corresponds to a parameterizable value, for example by a user.

According to yet another variant, the number of packets in the series is a parameter that can be configured dynamically and automatically by the device constructing the data frame. According to this last variant, the number of packets included in the series is determined as a function of the conditions or of transmission or of the quality of the connection between the first vehicle 10 on the one hand and the recipient (s) of the frame on the other hand. .

According to another variant, a number of identical packets included in said series is determined from a transmission performance indicator. Indicator performance thus corresponds to a parameter reflecting the quality of transmission conditions.

In particular, in one embodiment, the performance indicator comprises at least one of the elements among:

- a packet error rate (see below);

- a frame error rate (see below);

- an acknowledgment number (see below);

- a number of non-acknowledgments (see below).

The performance indicator is, for example, evaluated by the device constructing the frame (and on board the first vehicle 10) from indicators such as the PER (standing for “Packet Error Rate” or in French for “Contrat rate”. packet error ”), the FER (from English“ Frame Error Rate ”or in French“ Frame error rate ”), the number of acknowledgments or non-acknowledgments received. These indicators are for example determined from frames or data packets previously transmitted by the first vehicle 10, as a function of the returns made by the recipient (s) of the previously transmitted frames or data packets. The better the connection (weak PER and / or FER for example, or the higher number of acknowledgments compared to the number of previously transmitted packets), the lower the number of packets in the series (for example 2 or 3 identical packets in the series). Conversely, the worse the connection (high PER and / or FER for example, or low number of acknowledgments (or high number of non-acknowledgments) compared to the number of previously transmitted packets), the greater the number of packets in the series is important (for example 4 or 5 identical packages in the series)

In a second operation, the frame comprising the series of identical packets is transmitted according to a V2X communication mode, for example according to a direct communication mode. The frame is for example transmitted according to a broadcast transmission mode, that is to say to all the communication devices configured to communicate with the first vehicle 10 according to the V2X communication mode. This set includes for example the second vehicle 11, the pedestrian 12 and the cyclist 13 and is illustrated with a dotted circle in FIG. 1. According to another example, the frame is transmitted according to a multicast transmission mode, that is to say to several communication devices each identified. by their address. According to yet another example, the frame is transmitted according to a unicast transmission mode, that is to say to a single communication device identified by its address (for example the communication device worn by the pedestrian 12). The mode of transmission depends, for example, on the nature of the data included in the data packets of the series.

The consecutive transmission of several identical packets significantly increases the probability that the data contained in these packets will actually be received and decoded by the recipient (s) of these data packets.

Furthermore, the consecutive transmission of several identical packets makes it possible to considerably reduce the latency time between 2 data packets. In the state of the art, it is known to transmit a data packet again when the previously transmitted packet has not been received, at least in part, or when the data of the previously transmitted packet could not. be decoded correctly. The new transmission generally follows the receipt of a message from the recipient indicating to the sender that the packet has not been received or has not been decoded, for example via the transmission of a non-acknowledgment, says No-ACK or NACK. The latency time between the transmission of the first packet and the transmission of the second packet is then particularly high, which is very problematic when the data contained in the packets relate to emergency or distress situations. With the consecutive transmission of several identical data packets, the latency is reduced to a minimum. If the recipient has not received the first packet of the series correctly, he will immediately receive the following packets in the series without requesting them, which increases the probability of receiving and decoding all data, even if there are errors on some packages. The reliability of the connection is thus greatly improved. he

To further increase the reliability of the connection, according to an alternative embodiment, a different error detection code is associated with each of the packets in the series. Such an error detection code corresponds, for example, to a CRC (from the English "Cyclic Redundancy Check" or "Cyclic redundancy check" in French).

According to yet another variant, different error correction bits are associated with each packet. Such a variation improves the reliability of data transmission by increasing the likelihood that the data of partially transmitted or erroneously transmitted packets can be reconstructed from correctly received data. These bits correspond, for example, to FEC data (from English "Forward Error Correction" or in French "Error correction without return channel") or to a Reed-Solomon code.

[Fig. 2] schematically illustrates the structure of a data frame 2 transmitted by the first vehicle 10 to one or more recipients in the communication environment of FIG. 1, according to a particular and non-limiting example of the present embodiment. invention.

Frame 2 corresponds for example to a data frame conforming to the TCP protocol, such a protocol being described in document RFC 793 (in English "Requests for Comments" or in French "Requests for comments"). Frame 2 (also called segment) corresponds to a sequence of binary values, only the elements specific to the invention being shown in Figure 2.

Frame 2 comprises a frame header 20 followed by several packets or data segments. Each data packet conforms for example to the “GeoNetworking” protocol, the structure of such a data segment being for example described in document ETSI TS 102 636-4-1. A data segment is also called a data packet, for example described by the acronym GN-PDU (standing for “GeoNetworking Protocol Data Unit” or in French “Data Unit of the GeoNetworking Protocol”). Data segments intended for the same recipient (or several same recipients) are encapsulated in data frame 2.

According to another example, the data segments of frame 2 correspond to data packets of message (s) sent by the same vehicle (for example the first vehicle 10) to a “cloud” server (for example message data relating to emergency braking and an immediate danger from which the first vehicle is approaching).

The data frame 2 advantageously comprises a series 200 of several packets 21, 22, 23, 24 of identical data arranged consecutively in the data frame 2. In other words, the data packet 21 comprises the same payload data as each of the other packets. 22 to 24, each packet carrying the same set of data.

The series 200 of packets 21 to 24 advantageously corresponds to a TTI group 200. A transmission time interval, called TTI, is advantageously associated with each packet 21 to 24 for the transmission of each packet 21 to 24. The duration of the transmission interval is for example equal to 10, 20 or 40 ms.

Each data packet 21 to 24 includes the same payload data which advantageously corresponds to data relating to emergency, alert, distress and / or safety messages. These data are for example message data of the CAM and / or DENM type. These data are for example encoded in the GN-PDU data packets using encoding rules of the UPER type (standing for “Unaligned Packed Encoding Rules” or in French “Rules of encoding by non-aligned packet”) of the ASN.1 standard (from the English "Abstract Syntax Notation One" or in French "Notation de syntaxe abstrait 1").

According to a particular variant embodiment, a different error detection code is associated with each packet 21 to 24.

According to another particular variant embodiment, a different error correction code is associated with each packet 21 to 24. The structure of such a frame allows the consecutive transmission (from a temporal point of view) of each of the packets 21 to 24, the transmission of the first packet 21 being followed by the transmission of the second packet 22, which is followed by the transmission of the third packet 23, itself followed by the transmission of the fourth packet 24 of the 200 series.

Of course, the number of 200 series packages is not limited to 4 but extends to any number, for example 2, 3, 5, 6 or more packages.

[Fig. 3] schematically illustrates a device 3 configured to transmit data in the communication environment of FIG. 1, according to a particular and non-limiting embodiment of the present invention. The device 3 corresponds for example to a node on board the vehicle 10 or the vehicle 11 or to a node carried by a pedestrian, for example a smart phone. The device 3 is for example configured to transmit the data included in the frame 2. According to one variant, the device 3 is further configured to construct and generate the data frame 2 of FIG. 2.

The device 3 is for example configured for carrying out the operations described with reference to FIGS. 1 and 2 and / or the steps of the method described with reference to FIG. 4. Examples of such a device 3 include, without being there limited, on-board electronic equipment such as an on-board computer of a vehicle, an electronic computer such as an ECU ("Electronic Control Unit"), a roadside unit, a smart phone, a tablet, a computer laptop, a server. The elements of the device 3, individually or in combination, can be integrated in a single integrated circuit, in several integrated circuits, and / or in discrete components. The device 3 can be produced in the form of electronic circuits or software (or computer) modules or else a combination of electronic circuits and software modules. According to various particular embodiments, the device 3 is coupled in communication with other devices or similar systems, for example by means of a communication bus or through dedicated input / output ports. The device 3 comprises one (or more) processor (s) 30 configured to execute instructions for carrying out the steps of the method and / or for executing the instructions of the software (s) embedded in the device 3. The processor 30 can include integrated memory, an input / output interface, and various circuits known to those skilled in the art. The device 3 further comprises at least one memory

31 corresponding, for example, to a volatile and / or non-volatile memory and / or comprises a memory storage device which may comprise volatile and / or non-volatile memory, such as EEPROM, ROM, PROM, RAM, DRAM, SRAM, flash, magnetic or optical disc.

The computer code of the on-board software (s) comprising the instructions to be loaded and executed by the processor is for example stored on the first memory 31.

According to a particular and non-limiting embodiment, the device 3 comprises a block

32 interface elements to communicate with external devices, for example a remote server or the "cloud", other nodes of the ad hoc network. The interface elements of block 32 include one or more of the following interfaces:

- RF radiofrequency interface, for example of the Bluetooth® or Wi-Fi® type, LTE (from English "Long-Term Evolution" or in French "Long-term Evolution"), LTE-Advanced (or in French LTE-advanced );

- USB interface (from English "Universal Serial Bus" or "Bus Universel en Série" in French);

- FIDMI interface (from English "High Definition Multimedia Interface", or "Interface Multimedia Flaute Definition" in French).

Data is for example loaded to device 3 via the interface of block 32 using a Wi-Fi® network such as according to IEEE 802.11, an ITS G5 network based on IEEE 802.11 p or a mobile network such as a 4G network (or LTE Advanced according to 3GPP release 10 - version 10) or 5G, in particular an LTE-V2X network.

According to another particular embodiment, the device 3 comprises a communication interface 33 which makes it possible to establish communication with other devices (such as other computers of the on-board system when the device 3 corresponds to a on-board system computer) via a communication channel 330. The communication interface 33 corresponds for example to a transmitter configured to transmit and receive information and / or data via the communication channel 330. The communication interface 33 corresponds for example to a wired network of the CAN type (standing for “Controller Area Network” or in French for “Controllers Network”) or CAN FD (standing for “Controller Area Network Flexible Data-Rate” or in French “Réseau flexible data rate controllers ”).

According to a further particular embodiment, the device 3 can supply output signals to one or more external devices, such as a display screen, one or more speakers and / or other peripherals respectively via interfaces output not shown.

[Fig. 4] illustrates a flowchart of the various steps of a vehicle data transmission method, according to a particular and non-limiting exemplary embodiment of the present invention. The method is for example implemented by a device on board the vehicle 10 or by the device 3 of FIG. 3.

In a first step 41, a data frame is transmitted according to a vehicle-to-everything communication mode, called V2X. This data frame advantageously comprises a series of several identical and consecutive packets in the frame.

The data frame is for example received from a memory or from a device configured to build the data frame.

Of course, the invention is not limited to the embodiments described above but extends to a method for generating a data frame comprising the series of identical packets and to the device configured for implementing the method. frame generation. The invention also relates to a method for receiving a data frame comprising a series of identical and consecutive data packets, and the associated data frame receiving device.

The invention also relates to a vehicle, for example a motor vehicle or more generally a land motor vehicle, comprising the device 3 of FIG. 3.

Claims

1. A method of transmitting data for a vehicle (10), said method comprising a transmission (41) of a frame (2) of data according to a vehicle-to-all communication mode, called V2X, said frame (2) comprising a series. (200) of several identical and consecutive packets (21 to 24) in said frame (2).

2. Method according to claim 1, for which a different error detection code is associated with each of the packets (21 to 24) of said series (200).

3. Method according to claim 1 or 2, for which a different error correction code is associated with each of the packets (21 to 24) of said series (200).

4. Method according to one of claims 1 to 3, for which each packet (21 to 24) of said series (200) comprises the same set of identical data representative of an emergency message.

5. Method according to claim 4, for which said data of said set of data correspond to message data of the CAM or DENM type.

6. Method according to one of claims 1 to 5, for which a transmission time interval is associated with each packet (21 to 24) of said series (200), said series (200) forming a group of time intervals of transmission.

7. Method according to one of claims 1 to 6, for which a number of identical packets included in said series (200) is determined from a transmission performance indicator.

8. The method of claim 7, wherein the performance indicator comprises at least one of:

- a packet error rate;

- a frame error rate;

- an acknowledgment number;

- a number of non-acknowledgments.

9. Device (3) for transmitting data for a vehicle, said device comprising a memory (31) associated with at least one processor (30) configured for implementing the steps of the method according to any one of claims 1 to 8. .

10. Vehicle (10) comprising the device (3) according to claim 9.

11. Computer program product comprising instructions suitable for carrying out the process steps according to one of claims 1 to 8, when the computer program is executed by at least one processor.