System and method for obtaining diagnostic data in relation to a motor vehicle

Abstract

The invention proposes a method for transmitting diagnostic data in relation to a vehicle between a user terminal and a removable communication module connected to an ODB2 diagnostic port. The method comprises the following steps: the removable communication module, also referred to as a dongle, transmitting (102) presence beacons; receiving (104) a presence beacon; the user terminal sending (110) a pairing request, said pairing request comprising identification data; the module receiving (112) the pairing request; recording (114) the terminal identifier in the removable communication module; prohibiting (116) registration of identification data of an unknown user terminal in the removable communication module, such that said user terminal (32) then constitutes an exclusive user terminal associated with the removable communication module; and the removable communication module transmitting (120) diagnostic data to the exclusive user terminal.

Description

System and method for obtaining diagnostic data from a motor vehicle

[0001] The invention relates to monitoring data of a motor vehicle. More specifically, the invention relates to the recovery of diagnostic data of a motor vehicle. The subject of the invention is a method for transmitting diagnostic data of a motor vehicle. The invention also provides a system for transmitting diagnostic data of a motor vehicle. The invention also provides a removable communication module for transmitting diagnostic data of a motor vehicle.

[0002] During operation, a vehicle generates various operating data. Operating data includes specific events and operating parameters. Operating parameters include engine temperature, exhaust system clogging rate, fuel injection pressures, driving hours, energy consumption, and many other physical quantities and measurements. Operating data is used to assess a vehicle's operating conditions and predict the likelihood of a possible breakdown or maintenance need at a given time horizon. Thus, collecting operating data is useful for maintaining the reliability of vehicle components.

[0003] Operating data is commonly measured by on-board sensors and processors. It is collected by a control network, known as CAN, which stands for "Controller Area Network." Some of it is then stored on board memory attached to the vehicle. The operating data is then collected via a monitoring module that is plugged into the vehicle. The latter has a connection socket, or port, such as a connector known as ODB, which stands for "On-Board Diagnostic." A second-generation device, ODB2, is commonly deployed in current vehicles. The OBD2 on-board diagnostic device offers a diagnostic solution for engine failures.

[0004] Document KR20040066966A discloses a method and system for managing vehicle operating information by remote monitoring via Bluetooth® to reduce the costs required to manage operating information. vehicle operation using wireless LAN communication based on a Bluetooth® type communication protocol. A Bluetooth® dongle consists of a flash memory, a Bluetooth® module, a connector, a processor (central processing unit), and two backup capacitors; and is connected to an OBD (On-Board Diagnosis) system integrated in a vehicle via a connector. The memory stores faults not obtained via all kinds of sensors integrated in the OBD system. In the event that a vehicle is within a service area of ​​a hotspot equipped with an access point, the Bluetooth® module allows the vehicle to perform wireless LAN communication via Bluetooth® via an antenna.

[0005] US2007296559A1 discloses a system and method for controlling a portable communication device in a vehicle. The portable communication device is controlled by a workload protection or management module. To control the cellular phone, at least one transmitter is coupled to the diagnostic connector (e.g., an OBD-II connector) in the vehicle, which is coupled directly to the connector forming a receiver via a device commonly referred to as a "dongle." The transmitter receives instructions from the workload management module and transmits them to the cellular phone, preferably via a short-range wireless protocol such as Bluetooth®. In order for the cellular phone to properly interpret and act on these commands, an application program (e.g., a Java applet) is preferably downloaded to the phone by any suitable means.With the application program in place in the phone, commands from the workload management module or other control module in the vehicle can now be implemented on the cell phone, providing a safety and convenience advantage to the vehicle user.

[0006] In particular, document US2007296559A1 describes a vehicle comprising an on-board diagnostic port. A removable communication module with a “dongle” type housing is connected to the on-board port and communicates via Bluetooth® with a mobile phone. The on-board port communicates with vehicle sensors, and with a satellite geopositioning system.

[0007] However, each data transmission step exposes the vehicle user to communication leaks. The operating data contains data considered confidential, the dissemination of which the user wishes to control. Indeed, the removable communication module is likely to send information received and used by another communication terminal.

[0008] In addition, there is a risk that the transmitted operating data may not be collected correctly. Data may only partially reach the reference terminal, or arrive in the form of a damaged file. As a result, maintenance operations are carried out on biased or partial operating data. This means that vehicle safety is not maintained at a satisfactory level. Similarly, engine setting information may be based on incorrect data.

[0009] The invention aims to address at least one of the problems or drawbacks encountered in the prior art. In particular, the invention aims to improve the security of exchanges via a removable communication module. The invention also aims to optimize the security, speed, and quality of transmission of diagnostic data from a motor vehicle.

[0010] According to a first aspect, a method for transmitting diagnostic data of a motor vehicle between a user terminal and a removable communication module connected to a diagnostic port of the motor vehicle; remarkable in that the transmission method comprises the following steps: transmission of presence beacons by the removable communication module; reception of one of the presence beacons by the user terminal; sending of a pairing request by the user terminal; said pairing request comprising identification data of said user terminal; reception of the pairing request by the removable communication module; at least partial recording of the identification data in the removable communication module;then prohibiting the recording of identification data of a foreign user terminal in the removable communication module, so that said user terminal then constitutes an exclusive user terminal associated with the removable communication module; transmission of diagnostic data by the removable communication module to the exclusive user terminal.;

[0011] The invention allows the election of an exclusive user terminal, then prohibits the registration of another user terminal. The removable communication module ignores, or limits its interactions with any other user terminal. Thus, the removable communication module begins transmission only when there is certainty of the presence of the user terminal previously elected as exclusive.

[0012] Preferably, following the recording step, the method comprises a step of stopping the emission of presence beacons.

[0013] Preferably, at the recording stage, said data identification are recorded in a non-volatile memory of the removable communication module.

[0014] Preferably, the removable communication module comprises a recorded unlocking key; in the step of sending a pairing request by the user terminal; said pairing request comprises a transmitted unlocking key; and the method further comprises a step of comparing the transmitted unlocking key with the recorded unlocking key; then provided that the transmitted unlocking key corresponds to the recorded unlocking key, the method carries out the recording step.

[0015] Preferably, following the reception step; the method further comprises a step of defining a time-variable key in the identification data of the user terminal.

[0016] Preferably, at the transmission stage, the diagnostic data are encrypted according to said time-variable key.

[0017] Preferably, in the definition step the time variable key is calculated based on time data; and in the recording step, the time variable key is recorded in the removable communication module.

[0018] Preferably, the identification data includes a terminal identifier of the user terminal; in the definition step the time variable key is calculated based on the module identifier and the terminal identifier of the user terminal.

[0019] Preferably, from the data transmission step, the method comprises a step of iterative measurement of signal power by the removable communication module; then a step of comparing the signal power with a disconnection criterion; then a step of disconnecting the removable communication module from the exclusive user terminal when the signal power reaches the disconnection criterion.

[0020] Preferably, in the step of receiving the pairing request, the method comprises a step of initial measurement of a reference power of the pairing request by the removable communication module; the disconnection criterion is a function of the reference power.

[0021] Preferably, the disconnection criterion is at most 30% of the reference power, more preferably at most 50% of the reference power.

[0022] Preferably, the method further comprises: a step of receiving a subsequent terminal identifier from a subsequent user terminal; a step of comparing the subsequent terminal identifier with an exclusive terminal identifier of the exclusive user terminal; the method repeating the step of transmitting diagnostic data by the removable communication module provided that the subsequent terminal identifier corresponds to the exclusive terminal identifier.

[0023] Preferably, when the subsequent terminal identifier differs from the exclusive terminal identifier, the method comprises a step of erasing identification data by the removable communication module.

[0024] Preferably, at the step of sending a pairing request, the signal power of the pairing request is constant for a duration threshold, and / or the signal power of the pairing request is greater than or equal to a second power threshold.

[0025] Preferably, before the step of transmitting the presence beacons, the method comprises the following steps: starting a data transmission application on the user terminal; searching for a removable communication module by the user terminal; identifying a removable communication module by the user terminal.

[0026] Preferably, the disconnection step is a request blocking step.

[0027] Preferably, the diagnostic data includes event data, and in particular data from the live data display, i.e. operating parameters and values.

[0028] Preferably, when the issued unlocking key differs from the recorded unlocking key, the method comprises blocking transmissions by the user terminal and the removable communication module.

[0029] Preferably, the temporal data is temporal data defining the time variable key or a date of receipt of at least one presence beacon.

[0030] Preferably, the communication protocol is a short distance communication protocol.

[0031] Preferably, the method comprises a step of inserting the removable communication module into a communication port of the motor vehicle.

[0032] Preferably, at the emission stage, the presence tags include an encrypted removable communications module identifier.

[0033] Preferably, the step of defining a time-variable key is carried out after the recording step; and / or the time-variable key is defined by the removable communication module.

[0034] Preferably, following the transmission step, the method comprises a step of receiving the diagnostic data by the user terminal, then optionally a step of confirming receipt of said diagnostic data.

[0035] Preferably, the terminal identifier is a unique terminal identifier.

[0036] Preferably, the disconnection criterion is a signal strength criterion.

[0037] Preferably, at the registration step, the terminal identifier is recorded in a flash memory of the removable communication module.

[0038] Preferably, at the transmission stage, the user terminal is in the motor vehicle.

[0039] Preferably, at the transmission stage, the motor vehicle is moving.

[0040] Preferably, at the transmission stage, the diagnostic data is encrypted.

[0041] Preferably, after the disconnection step and / or before the diagnostic data transmission step, the method comprises the steps of: • detection of a subsequent user terminal; • communication of a subsequent user identifier; • comparison of the subsequent user identifier to the exclusive user terminal identifier; • pairing of the removable communication module and the exclusive user terminal if the subsequent user identifier matches the exclusive user terminal identifier.

[0042] Preferably, the method further comprises a step of decrypting the vehicle diagnostic data by the user terminal.

[0043] Preferably, the step of sending the pairing request and the transmission step comprise the use of a communication protocol with a range of at most 10 meters, preferably at most 5 meters.

[0044] Preferably, at the transmission step, the pairing power level is greater than or equal to a second power level threshold.

[0045] Preferably, after the transmission step, the method comprises a step of erasing transmitted diagnostic data.

[0046] Preferably, in the step of sending the pairing request, the user terminal is at a first distance from the removable communication module, and in the transmission step, the user terminal is at a second distance from the removable communication module; the second distance being at most five times greater than the first distance.

[0047] Preferably, the method comprises a step of acquiring monitoring data from the motor vehicle, then a step of converting the acquisition data into diagnostic data.

[0048] According to another aspect, the invention proposes a method for transmitting diagnostic data of a motor vehicle between a user terminal and a removable communication module connected to a diagnostic port of the motor vehicle; the removable communication module having a recorded unlocking key and the user terminal comprising a terminal identifier; remarkable in that the transmission method comprises the following steps: transmission of presence beacons by the removable communication module; reception of one of the presence beacons by the user terminal; sending of a pairing request by the user terminal; said pairing request comprising a transmitted unlocking key and the terminal identifier of said user terminal; reception of the pairing request by the removable communication module; comparison of the transmitted unlocking key with the recorded unlocking key;then, provided that the issued unlocking key matches the registered unlocking key, registering the terminal identifier in the removable communication module; and transmitting diagnostic data by the removable communication module to the user terminal.;

[0049] According to another aspect, the invention proposes a system for transmitting operating data from a motor vehicle; the transmission system comprising a user terminal, and a removable communication module intended to be connected to a diagnostic port of the motor vehicle; the removable communication module storing a recorded unlocking key and the user terminal comprising a terminal identifier; remarkable in that the transmission system is suitable for: • emit presence beacons with the removable communication module; • receive one of the presence beacons by the user terminal; • send a pairing request by the user terminal; said pairing request comprising an issued unlocking key and the terminal identifier of said user terminal; • receive the pairing request via the removable communication module; • compare the issued unlocking key with the registered unlocking key; then, provided that the issued unlocking key matches the registered unlocking key: • record the terminal identifier in the removable communication module; and • transmit diagnostic data via the removable communication module to the user terminal.

[0050] Preferably, the user terminal is an exclusive user terminal.

[0051] According to another aspect, the invention proposes a computer program comprising instructions which, when the program is executed by a computer, cause the latter to implement a method for transmitting diagnostic data of a motor vehicle between an exclusive user terminal and a removable communication module connected to a diagnostic port of the motor vehicle; the removable communication module having a module identifier; remarkable in that the transmission method comprises the following steps: emission of presence beacons by the removable communication module; reception of a pairing request by the removable communication module; said pairing request comprising identification data of said exclusive user terminal; at least partial recording of the identification data of the exclusive user terminal in the removable communication module;and prohibition of recording identification data of a foreign user terminal in the removable communication module; transmission of diagnostic data by the removable communication module to the exclusive user terminal.;

[0052] According to another aspect, the invention proposes a removable communication module for a system for transmitting operating data from a motor vehicle to an exclusive user terminal comprising identification data. tion, said removable communication module being intended to be connected to an on-board diagnostic port of a motor vehicle; characterized in that said removable communication module is configured to: emit presence beacons; receive a pairing request from an exclusive user terminal; said pairing request comprising identification data of said exclusive user terminal; prohibit recording of identification data of a foreign user terminal in the removable communication module; record at least partially the identification data; and transmit diagnostic data to the exclusive user terminal.

[0053] According to another aspect, the invention provides a motor vehicle comprising a removable communication module and / or a transmission system remarkable in that the communication module is in accordance with the invention and / or the transmission system is in accordance with the invention.

[0054] Preferably, the vehicle comprises first diagnostic data and second diagnostic data; the second data comprising positioning data and / or time data; in the transmission step only the first diagnostic data being transmitted.

[0055] Thus, the invention protects confidential data since sensitive data does not pass through the communication module.

[0056] The invention will be well understood and other aspects and advantages will appear clearly on reading the following description, given with reference to the appended figures and listed below.

[0057] Figure 1 is a side view of a motor vehicle with a transmission system according to the invention.

[0058] Figure 2 is a diagram of a transmission method according to the invention.

[0059] Figure 3 is a diagram of a communication protocol according to the invention.

[0060] In the following description, the term "comprise" is synonymous with "include" and is not limiting in that it allows for the presence of other elements in the motor vehicle, the transmission system or other steps in the method to which it relates. It is understood that the term "comprise" includes the terms "consist of".

[0061] Diagnostic data means data comprising codes relating to specific anomalies or events detected during the operation of the motor vehicle. Diagnostic data includes codes corresponding to measurements showing a variation from a reference threshold.

[0062] In this description, the ranges of values ​​include the limits which delimit them.

[0063] Throughout the description, the different figures use the same reference signs to designate identical or similar entities.

[0064] Figure 1 represents a motor vehicle 10 according to the invention. The motor vehicle 10 comprises energy storage means 12 and at least one motor 14 adapted to drive said motor vehicle 10.

[0065] The motor vehicle 10 comprises at least one sensor 16, preferably a plurality of sensors 16. The sensors 16 make it possible to measure physical quantities, such as operating data of the motor vehicle 10. The sensors 16 are adapted to measure temperatures of the energy storage means 12 and of the engine 14, a charge level of the energy storage means 12, a pressure of the engine 14. The sensors can measure temperature and / or pressure data of a heat exchanger system (not shown), a steering system, a suspension system, a braking system. This list is not exhaustive.

[0066] Generally, at least one or each sensor 16 is configured to provide physical data of a mobile and / or actuatable entity of the motor vehicle 10.

[0067] The operating data may include time data, such as operating times. It may include data on one or more operating states of safety devices. For example, it may include diagnostic data on the operating state of an airbag system (not shown), commonly referred to as an "airbag."

[0068] The motor vehicle 10 further comprises a local communication network (not shown). The local communication network can at least connect the sensors 16.

[0069] The motor vehicle 10 comprises an on-board computer 20 with an on-board memory and a calculator. The memory of the on-board computer 20 is capable of storing the operating data of the motor vehicle 10 as they are sent by the sensors 16. The calculator can perform calculations on the operating data. operation and generate diagnostic data by performing logic tests on the measured operating data. The diagnostic data is recorded in the on-board memory.

[0070] The motor vehicle 10 also comprises a port, forming a connection socket. The port may be an external port. It may be a peripheral. The port is an on-board diagnostic port 22. The on-board diagnostic port 22 is connected to the on-board computer 20; directly or via the local communication network. Thus, the on-board diagnostic port 22 provides access to the operating data stored in the on-board memory.

[0071] The motor vehicle 10 is equipped with a transmission system 24. The transmission system 24 is capable of transmitting data from the motor vehicle; for example, diagnostic data from the motor vehicle 10. The transmission system 24 may include the on-board diagnostic port 22.

[0072] The transmission system 24 has a removable communication module 30. The removable communication module 30 includes a housing housing an external memory and an external processor (not shown). The removable communication module 30 is connected to the on-board diagnostic port 22.

[0073] The on-board diagnostic port 22 and / or the removable communication module 30 are configured to send requests to the on-board memory in order to obtain diagnostic data. The transmission system 24 accommodates a user terminal 32. The user terminal 32 may be of the touch pad type, or of the cellular telephone type; also called a “smartphone”. The user terminal 32 may be a smart portable device. It may be a portable computer; in particular in that it includes its own power supply. The user terminal 32 includes a visual interface, an interface for manual data entry by a user, a terminal memory, and a terminal processor (not shown). The terminal processor and the terminal memory may form a computer, for example a terminal computer.

[0074] The terminal processor may include one or more programmable electronic microprocessors or microcontrollers. In addition, the terminal processor may include a central processing unit (CPU), dedicated memory (in addition to or as the terminal memory), and an input / output (I / O) interface through which the terminal processor may receive a plurality of input signals. Such an I / O interface is also configured to generate a plurality of input signals. output including, but not limited to, those used to control and / or provide diagnostic data to the on-board diagnostic port 22 or other systems of the motor vehicle 10.

[0075] The terminal memory is provided for storing data and instructions or code (i.e., computer software comprising code instructions) readable and / or writable by the terminal processor. The terminal memory may include various forms of non-volatile (i.e., non-transitory) memory. The non-volatile memory includes flash or read-only memory (ROM), any type of programmable read-only memory (e.g., PROM, EPROM, EEPROM). The terminal memory optionally includes volatile memory, including random access memory (RAM), static random access memory (SRAM), dynamic random access memory (DRAM), and synchronous dynamic random access memory (SDRAM). According to the invention, the terminal memory may be internal to the terminal processor, or alternatively form a separate component.

[0076] The user terminal 32 communicates with the removable communication module according to a short-range wireless communication protocol; for example, of the Bluetooth® type. The Bluetooth® protocol is a telecommunications protocol for the bidirectional exchange of data over short distances using radio waves. The Bluetooth® protocol uses a frequency band between 2400 MHz and 2483.5 MHz. Several communication channels are defined in this frequency band. In the context of the invention, the choice of the Bluetooth® protocol limits interference due to the narrowness of its frequency band. Furthermore, its power level limits its range in order to limit the potential receivers formed by one or more user terminals. The metal structure of the motor vehicle tends to limit the range outside the passenger compartment.Thus, the invention secures the transmission of data in the sense that it reduces the number of potential recipients.

[0077] Generally speaking, the communication protocol is a short-distance communication protocol, preferably with a range of at most 20 meters, more preferably at most 10 meters; possibly at most 5 meters.

[0078] Figure 2 shows a diagram of a method for transmitting operating data of a motor vehicle according to the invention. The motor vehicle may correspond to that shown in relation to Figure 1.

[0079] The transmission process includes the following steps, notably performed in the following order: • insertion 100 of the removable communication module into a communication port of the vehicle; • emission 102 of presence beacons by the removable communication module, said removable communication module comprising a recorded unlocking key; • reception 104 of one of the presence beacons by the user terminal; • initial measurement 106 of a reference power of the pairing request by the removable communication module; • definition 108 of a time variable key which is calculated based on time data in the identification data of the user terminal; • sending 110 of a pairing request by the user terminal; said pairing request comprising the identification data and an unlocking key sent by said user terminal, and therefore its time variable key; • reception 112 of the pairing request by the removable communication module; • comparison 113 of the issued unlocking key with the registered unlocking key; then provided that the issued unlocking key corresponds to the registered unlocking key, • recording 114 of identification data in the removable communication module, and in particular of the time variable key; • prohibition 116 of recording identification data of a foreign user terminal in the removable communication module, so that said user terminal then constitutes an exclusive user terminal associated with the removable communication module; • stop 118 of the emission of presence beacons; • transmission 120 of diagnostic data by the removable communication module to the exclusive user terminal; • reception 122 of diagnostic data by the exclusive user terminal; • iterative measurement 124 of signal power by the removable communication module; then • comparison 126 of the measured signal power with respect to a disconnection criterion; then disconnection 128 of the removable communication module from the exclusive user terminal when the signal power reaches the disconnection criterion; • receipt 130 of a subsequent terminal identifier from a subsequent user terminal; • comparison 132 of the subsequent terminal identifier with the identification data; • pairing 134 of the removable communication module and the subsequent user terminal if the subsequent terminal identifier corresponds to the identification data, and resumption or start of the transmission step 120 of diagnostic data by the removable communication module provided that the subsequent terminal identifier corresponds to the identification data; • decryption 136 of vehicle diagnostic data by the user terminal.

[0080] The user terminal is called an exclusive user terminal in the sense that it is the only one that can pair with the communication module. It is the first user terminal to successfully pair with the removable communication module. Its identification data is exclusive identification data. It includes its terminal identifier, which is a unique identifier specific to each terminal.

[0081] Generally, the steps of the transmission method use a short-distance communication protocol, for example a Bluetooth® protocol. The short-distance communication protocol is understood to be a protocol whose range is at most 20 meters, preferably at most 10 meters. Beyond these distances, the power of the received signal involves losses of information, for example of at least 10%.

[0082] At the insertion step 100, the communication module is powered. It is powered after the vehicle is switched on. In particular, its external processor and its communication means are powered. The communication means comprise an antenna capable of operating in transmission and reception.

[0083] In the transmission step 102, the presence beacons are encrypted; and in the reception step 104 of one of the presence beacons, the user terminal decodes said presence beacon. The presence beacons comprise a signature, or module identifier, making it possible to identify the removable communication module. The signature makes it possible to detect that the removable communication module is part of the transmission system. This detection is carried out through the application installed on the user terminal. The presence beacons are transmitted at regular intervals, for a predetermined duration from the switching on or the insertion step 100.

[0084] In the transmission step 102, the presence beacons comprise an encrypted removable communication module identifier. This identifier is decrypted by the application executed by the user terminal. This prevents a terminal not equipped with the dedicated application from being able to identify or recognize the removable communication module. Confidentiality is thus prioritized.

[0085] Before the step 102 of transmitting the presence beacons, the transmission method may comprise the following steps (not shown), and carried out by the user terminal: starting a data transmission application on the user terminal; searching for a removable communication module by the user terminal; identifying the removable communication module by the user terminal. The step of identifying the removable communication module is triggered by the reception of one of the presence beacons. Generally speaking, the step of starting the application may be a step of sending a declaration of ready-to-pair state. The reception of the presence beacons allows a change of state of the removable communication module; which goes from a standby state to a reactivation state.

[0086] Before the step 102 of transmitting the presence beacons, the method comprises a step of acquiring monitoring data from the motor vehicle, then a step of converting the monitoring data into diagnostic data. The step of acquiring monitoring data may be a step of reading the monitoring data. The acquisition step makes it possible to obtain, continuously or at regular intervals, physical quantities specific to the operation of the motor vehicle. Then, during the conversion step, these physical quantities are compared to tolerance thresholds in order to identify possible anomalies, and therefore to carry out a real-time diagnosis of the vehicle. These anomalies are advantageously translated by predefined designations; which are in turn encrypted. They form diagnostic data. More generally, the diagnostic data may comprise data relating to events.Communicating diagnostic data indirectly reduces the weight of messages sent while optimizing diagnostic accuracy and communication time. Decoding time is also reduced.

[0087] The initial measurement step 106 is carried out from, or after, the reception step 112 of the pairing request. The disconnection criterion is a function of the reference power. The disconnection criterion; and therefore of communication cut-off; is at most 30% of the reference power, preferably at most 50% of the reference power. The disconnection criterion is also understood as a power criterion. This power level requires proximity to the user terminal, and in particular a presence in the passenger compartment. This limits the number of terminals likely to communicate with the removable communication module.

[0088] In the step 108 of defining the time-variable key, this is defined by the user terminal which then becomes exclusive. The time-variable key comprises an AES key; corresponding to the acronym for the English expression “Advanced Encryption Standard”. The time-variable key is integrated into the identification data of the exclusive user terminal. The AES key is advantageously an AES 256 key, which optimizes security and calculations. According to one option, in the transmission step 120, the diagnostic data are encrypted according to said time-variable key.

[0089] In the definition step 108, the time-variable key is calculated based on time data that comes from the internal clock of the exclusive user terminal. The time data may correspond to the date of definition of the time-variable key, or the date of reception of the at least one presence beacon. In this alternative, the date is the date of the step 106 of reception of the beacon which allows the process to continue. By date, we mean a point in time defined to the nearest minute, preferably to the nearest second, more preferably to the nearest tenth of a second. The time data is applied to a time function, for example an elliptic function, providing a time code.

[0090] The identification data specific to the exclusive user terminal includes its exclusive terminal identifier. They form a recorded unlocking key. In definition step 108 the time-variable key is calculated based on the module identifier and the terminal identifier of the exclusive user terminal. The time-variable key is calculated by multiplying the identifiers with the time code. Other operations are possible to further increase security.

[0091] The invention therefore combines a temporal data which selects a point on a curve following a temporal law, codes it according to a mathematical function, then combines it with the terminal identifier and the module identifier. Thus, there is uniqueness of the data allowing the pairing since they are based on the identities of the paired entities, of a temporal data coded by a security function. Thus, security is reinforced.

[0092] In the step 110 of sending a pairing request, the power of the signal of the pairing request is constant for a duration threshold, and / or the power The signal strength of the pairing request is greater than or equal to a second power threshold. This aspect adds security because it prevents accidental connections.

[0093] The pairing request may include a query message with a request to initiate pairing between the user terminal and the removable communication module; and further includes the unlocking code of the transmission system.

[0094] In the step 110 of sending the pairing request, the user terminal is at a first distance from the removable communication module, and in the transmission step, the user terminal is at a second distance from the removable communication module; the second distance being at most five times greater than the first distance.

[0095] The step 112 of receiving the pairing request, or the step 114 of recording the identification data, may comprise a sub-step of confirming the pairing, for example with sending a confirmation message from the removable communication module to the exclusive user terminal.

[0096] The comparison step 113 of the issued unlocking key with the recorded unlocking key is performed by the removable communication module. This aspect increases security since a single device centralizes the key steps. In addition, this optional intermediate step adds a level of security since it requires a first verification code to be able to continue the rest of the process. If, at the end of the comparison, the issued unlocking key differs from the recorded unlocking key, the method continues the execution of the step (102) of transmitting a presence beacon by the removable communication module.

[0097] In the step 114 of recording the terminal identifier, said terminal identifier is recorded on a non-volatile memory of the removable communication module. The terminal identifier is recorded in a flash memory of the removable communication module. Thus, this terminal identifier remains despite a power cut of the removable communication module. Once the recording is carried out, the terminal is therefore paired with the removable communication module. The identifier of the removable communication module is recorded in the paired terminal.

[0098] In the prohibition step 116, the removable communication module blocks the recognition of a foreign user terminal (i.e. a terminal other than the one that has just been paired in the registration step 114). The option to recognize a new user terminal is deleted. The data specific to the latter are not retained after receipt. The removable communication module closes the possibility of recording any other identification data.

[0099] Generally, the prohibition step can be a step of erasing data from a foreign user terminal.

[0100] According to one embodiment, the prohibition step 116 is implemented once the terminal has been paired (registration step 114), the identifier of the removable communication module also being advantageously recorded in the terminal. The terminal (via the dedicated application) then sends a locking request to the removable communication module. The reception of this locking request by the removable communication module results in the execution of a script which makes it unable to send a pairing code to other terminals and / or deactivates the emission of presence beacons, for example by masking this information in the removable communication module.

[0101] Bilaterally, the terminal can no longer pair another removable communication module. To do this, the application running on the terminal is configured to prohibit two pairings, even after uninstalling the application. The first pairing is recorded in a hidden log file, and therefore leaves a trace there, so that reinstalling the application on the terminal does not allow re-pairing a different removable communication module (i.e. with a different identifier).

[0102] In the transmission step 120, the diagnostic data are encrypted according to said time-variable key, which is recorded on both sides of the transmission system. This key is then used to encode and decode the exchanged information.

[0103] Following the data transmission step 120, when the subsequent terminal identifier differs from the identification data specific to the exclusive user terminal, at the end of the comparison step 132; the terminal present is a user terminal foreign to the system. According to one option, the method then executes a step 138 of erasing the terminal identifier considered foreign by the removable communication module. The method therefore locks the possibility of pairing with a user terminal.

[0104] In the transmission step 120, the exclusive user terminal is in the motor vehicle. Thus, the user terminal is able to receive this data when the motor vehicle is moving. It can receive and decode it. Ultimately, the user is able to interpret the diagnostic data, and only he is capable of doing so since he has compatible credentials. He is the only one likely to communicate with the communication module. Security is enhanced.

[0105] In the transmission step 120, the pairing power level is greater than or equal to a second predefined power level threshold. If the pairing power level is less than a second threshold, it is considered that the exclusive user terminal is not close enough to the communication module; and that a security criterion is no longer met. From then on, the method returns to the step 102 of transmitting presence beacons.

[0106] In the iterative signal power measurement step 124, the removable communication module can measure signal powers of requests for transmission of diagnostic data and / or signal powers of confirmation of receipt of diagnostic data. According to an alternative of the invention, the iterative signal power measurement step is carried out by the user terminal; for example on the frames of the sending of diagnostic data.

[0107] Following the step 138 of erasing the terminal identifier by the removable communication module when the subsequent terminal identifier differs from the identification data; the method restarts its execution at the step 102 of transmitting the presence beacons.

[0108] In the signal power comparison step 126, as long as the signal power does not reach the disconnection criterion, the method continues the diagnostic data transmission step 120.

[0109] Figure 3 shows a diagram of a protocol for transmitting diagnostic data of a motor vehicle according to the invention. The motor vehicle may correspond to that shown in relation to Figure 1. The transmission protocol may be integrated into the transmission method shown in relation to Figure 2.

[0110] Horizontal arrows between the two dotted rails indicate signals sent between the removable communication module 30 and the user terminal 32. The direction of the arrowhead indicates the direction of travel of the signal. A possible foreign user terminal 34 is shown. Its architecture is similar to that of the user terminal 32; however, their identifiers differ.

[0111] The transmission protocol includes the following steps: • emission 102 of presence beacons at regular intervals; for example when the vehicle is put into APC mode, in particular for a predefined period; • reception 104 of one of the presence beacons; • definition 108 of a time variable key; • sending 110 of a pairing request; said pairing request comprising a sent unlocking key and identification data of the terminal identifier; • reception 112 of the pairing request; • comparison 113 of the issued unlocking key with the registered unlocking key; then, provided that the issued unlocking key corresponds to the registered unlocking key: • recording 114 of the terminal identifier in the removable communication module; • prohibition 116 of recording identification data of a foreign user terminal so that said user terminal 32 then constitutes an exclusive user terminal associated with the removable communication module 30; and • transmission 120 of diagnostic data to the exclusive user terminal; • confirmation 140 of receipt of diagnostic data; • disconnection 128 of the exclusive user terminal 32; • sending 142 of a pairing request by a foreign user terminal 34 with its identifier; • deletion 138 of the identifier of the foreign user terminal 34.

[0112] During the step 102 of transmitting presence beacons, the removable communication module 30 is in a state ready to pair for a first pairing; also called exclusive pairing since it makes it possible to define the exclusive user terminal with which it will have the capacity to pair.

[0113] It is noted that the sending of presence beacons is interrupted with or following the registration step 114. The sending of presence beacons can resume from the disconnection step 128; for example by modifying the presence beacons.

[0114] After the disconnection step 128, the exclusive removable communication module 30 again transmits presence beacons. This new sending can start as soon as the removable communication module 30 is powered, or after a predefined duration after the disconnection step 128. In the presence beacon transmission step 102, said presence beacons can be first presence beacons; for example with an availability message for defining an exclusive pairing. After the disconnection step 128, the presence beacons are optionally second presence beacons, without an availability message for defining an exclusive pairing.

[0115] According to one option of the invention, at the registration step 114 the removable communication module 30 sends a pairing confirmation, signifying to the user terminal 32 that they are paired. Thus, the user terminal 32 becomes the exclusive user terminal. They form a closed communication network.

[0116] After disconnection, the exclusive user terminal 32 and the removable communication module 30 are able to pair again; and therefore to communicate again, for example after the erasure step 138 and / or after the disconnection step 128. In this context, one or the other sends presence messages or pairing requests. When the exclusive user terminal 32 communicates its terminal identifier, the pairing is effective. The same coding characteristics described above are applied.

[0117] Only the exclusive user terminal automatically connects to the removable communication module 30 and automatically retrieves diagnostic data from it through a diagnostic data request. This request includes the identification data of the exclusive user terminal which allows the removable communication module to recognize it. In this way, the invention optimizes the security and speed of retrieving diagnostic data.

[0118] In the case where the possible foreign user terminal 34 issues a connection request, this request is ignored since it occurs after the registration prohibition step 116. This foreign user terminal 34 may have started the same data transmission application as the exclusive user terminal. During such a request, the foreign user terminal 34 communicates its subsequent terminal identifier. Since the removable communication module 30 receives this foreign user terminal identifier, it compares it to the identification data of the exclusive user terminal. To the extent that these identifiers differ, the removable communication module 30 prohibits pairing. Indeed, even if the foreign user terminal uses the same time function as the user terminal, their own identifiers differ. In addition, the foreign pairing request date will also differ.

[0119] Then, the removable communication module 30 deletes the foreign terminal identifier from its internal memory after the comparison which has proven negative. Therefore, even if the foreign user terminal 34 uses the compatible application with the removable communication module 30, the latter does not establish pairing or data transmission. Thus, security is preserved. At the same time, it deletes the corresponding data to preserve its memory.

Claims

Claims 1. Method for transmitting diagnostic data of a motor vehicle (10) between a user terminal (32) and a removable communication module (30) connected to a diagnostic port of the motor vehicle (10); characterized in that the transmission method comprises the following steps: • emission (102) of presence beacons by the removable communication module (30); • reception (104) of one of the presence beacons by the user terminal (32); • sending (110) of a pairing request by the user terminal (32); said pairing request comprising identification data of said user terminal (32); • reception (112) of the pairing request by the removable communication module (30); • recording (114) at least partially of the identification data in the removable communication module (30); then • prohibition (116) of recording identification data of a foreign user terminal in the removable communication module (30), so that said user terminal (32) then constitutes an exclusive user terminal associated with the removable communication module (30); • transmission (120) of diagnostic data by the removable communication module (30) to the exclusive user terminal (32).

2. Method according to claim 1, characterized in that following the recording step (114), the method comprises a step of stopping (118) the emission of presence beacons; preferably in the recording step (114), said identification data are recorded in a non-volatile memory of the removable communication module (30).

3. Method according to one of claims 1 to 2, characterized in that the removable communication module (30) comprises a recorded unlocking key; in the step of sending (110) a pairing request by the user terminal (32); said pairing request comprises a transmitted unlocking key; and the method further comprises a step of comparing (113) the transmitted unlocking key with the recorded unlocking key; then provided that the transmitted unlocking key corresponds to the recorded unlocking key, the method carries out the recording step (114).

4. Method according to one of claims 1 to 3, characterized in that following the reception step (104); the method further comprises a definition step (108) of a time-variable key in the identification data of the user terminal (32), preferably in the transmission step (120), the diagnostic data are encrypted according to said time-variable key.

5. Method according to claim 4, characterized in that in the definition step (108) the time-variable key is calculated as a function of a time data item; and in the recording step (114), the time-variable key is recorded in the removable communication module.

6. Method according to one of claims 4 to 5, characterized in that the identification data comprises a terminal identifier of the user terminal (32); in the definition step (108) the time variable key is calculated as a function of the module identifier and the terminal identifier of the user terminal (32).

7. Method according to one of claims 1 to 6, characterized in that from the step of transmitting (120) data, the method comprises a step of iterative measurement (124) of signal power by the removable communication module (30); then a step of comparing (126) the signal power with respect to a disconnection criterion; then a step of disconnecting (128) the removable communication module (30) from the exclusive user terminal (32) when the signal power reaches the disconnection criterion.

8. Method according to claim 7, characterized in that in the step of receiving (112) the pairing request, the method comprises an initial measurement step (106) of a reference power of the pairing request by the removable communication module (30); the disconnection criterion is a function of the reference power.

9. Method according to claim 8, characterized in that the disconnection criterion is at most 30% of the reference power, preferably at most 50% of the reference power.

10. Method according to one of claims 1 to 9, characterized in that the method further comprises: a step of receiving (130) a subsequent terminal identifier of a subsequent user terminal; a step of comparing (132) the subsequent terminal identifier with an exclusive terminal identifier of the exclusive user terminal; the method repeating the step of transmitting (120) diagnostic data by the removable communication module (30) provided that the subsequent terminal identifier corresponds to the exclusive terminal identifier.

11. Method according to claim 10, characterized in that when the subsequent terminal identifier differs from the exclusive terminal identifier, the method comprises a step of erasing (138) identification data by the removable communication module (30).

12. Method according to one of claims 1 to 11, characterized in that in the step of sending (110) a pairing request, the signal power of the pairing request is constant for a duration threshold, and / or the signal power of the pairing request is greater than or equal to a second power threshold.

13. Method according to one of claims 1 to 12, characterized in that before the step of transmitting (102) the presence beacons, the method comprises the following steps: • starting a data transmission application on the user terminal (32); • search for removable communication module (30) by the user terminal (32); • identification of a removable communication module (30) by the user terminal (32).

14. Computer program comprising instructions which, when the program is executed by a computer, cause the latter to implement a method for transmitting diagnostic data of a motor vehicle (10) between a user terminal (32) and a removable communication module (30) connected to a diagnostic port of the motor vehicle (10); the removable communication module (30) having a module identifier; characterized in that the transmission method comprises the following steps: • emission (102) of presence beacons by the removable communication module (30); • reception (112) of a pairing request by the removable communication module (30); said pairing request comprising identification data of said user terminal (32); • recording (114) at least partially the identification data of the user terminal (32) in the removable communication module (30); and • prohibition (116) of recording identification data of a foreign user terminal in the removable communication module (30), so that said user terminal (32) then constitutes an exclusive user terminal associated with the removable communication module (30); • transmission (120) of diagnostic data by the removable communication module to the exclusive user terminal (32).

15. Removable communication module (30) of a system for transmitting operating data from a motor vehicle (10) to a user terminal (32) comprising identification data, said module removable communication module (30) being intended to be connected to an on-board diagnostic port of a motor vehicle (10); characterized in that said removable communication module (30) is configured to: • emit presence beacons; • receive a pairing request from a user terminal (32); said pairing request comprising identification data of said user terminal (32); • prohibit recording of identification data of a foreign user terminal in the removable communication module (30), so that said user terminal (32) then constitutes an exclusive user terminal associated with the removable communication module (30); • record at least partially the identification data; and • transmit diagnostic data to the exclusive user terminal

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