Using a portable identifier to communicate with a vehicle system

Abstract

A method is proposed for using a portable identifier configured to communicate with a vehicle system. The portable identifier includes a power source. The method comprises, using the portable identifier for at least one communication protocol, the following four steps. The first step is detection (S10) of a loss of communication with the system. The second step is determination (S20) of the number of steps taken by a user between the detected loss of communication and the deactivation of the portable identifier. The third step, after reactivation of the identifier, is monitoring (S30) of the number of steps taken by the user. The fourth step is triggering (S40) communication using the communication protocol with the system when the monitored number of steps exceeds the determined number of steps. The method provides improved use of the portable identifier. [Fig. 1]

Description

Title of the invention: Use of a portable identifier to communicate with a vehicle system technical field

[0001] This disclosure relates to a method of using a portable identifier, a computer program for such a portable identifier, a storage medium for such a program, and a portable identifier. Technical background

[0002] Vehicles equipped with systems that have stored one or more portable identifiers now exist. These portable identifiers can be portable devices such as key fobs or smartphones. Each identifier includes a source of electrical power (for example, a battery) enabling it to be portable. Such systems allow the vehicle to perform functions, such as unlocking the doors and / or starting the vehicle, depending on the location of one or more portable identifiers.

[0003] To perform these functions, each wearable device can be configured to communicate with the system using one or more communication protocols. For example, the wearable device and the system can be configured to communicate using an UWB (Ultra Wide Band) communication protocol and a BLE (Bluetooth Low Energy) communication protocol. However, using one or more of these communication protocols reduces the lifespan of the wearable device's power source.

[0004] There is therefore a need to improve the use of such a portable identifier. Summary

[0005] A method is proposed for this purpose of using a portable identifier configured to communicate using one or more communication protocols with a vehicle system that has registered the portable identifier. The portable identifier includes a source of electrical power. The method comprises, using the portable identifier, for at least one communication protocol, the following four steps. The first step is a detection of loss of communication using the communication protocol with the system. The second step is a determination of the number of steps taken by a user wearing the portable identifier between the detected loss of communication and the deactivation of the portable identifier. The third step is, After reactivating the identifier, the number of steps taken by the user wearing the wearable identifier is monitored. The fourth step is a communication trigger using the communication protocol with the system when the monitored number of steps exceeds the predetermined number of steps.

[0006] For each communication protocol, communication can be triggered when the following inequality is satisfied:

[0007] Count _not > Not_destin - Not _loss + K,

[0008] in which Count_steps is the number of steps monitored, Steps_desti is the number of steps taken by the user between exiting the vehicle by the user and deactivation of the portable identifier, Steps_loss is the number of steps taken by the user between exiting the vehicle by the user and the detected loss of communication and K, is a parameter dependent on the communication protocol.

[0009] The one or more communication protocols may include a UWB communication protocol and / or a BLE communication protocol.

[0010] For at least one protocol, the triggering can be performed based on:

[0011] - at a user speed,

[0012] - a comparison of one or more RSSI measures of determined BLE exchanges during monitoring (S30) with one or more RSSI measurements of BLE exchanges at the time of detected communication loss for each communication protocol, and / or

[0013] - of a number of steps taken by the user between exiting the vehicle by the user and the detected loss of communication.

[0014] The identifier may include a pedometer. The determination of the number of steps and / or the monitoring of the number of steps may include one or more measurements of the number of steps by the pedometer.

[0015] The identifier may include a microcontroller and, for each communication protocol, a respective component. The communication triggering may include, for each communication protocol, the sending of a wake-up signal by the microcontroller to the respective component of the communication protocol.

[0016] The electrical energy source can be a battery, preferably a button cell, and / or have a diameter of less than 25 millimeters and / or a height of less than 8 millimeters, for example less than 6 millimeters.

[0017] A computer program for such a portable identifier is also proposed. The computer program includes instructions which, when the program is executed by a processor, cause the processor to implement such a method.

[0018] A computer-readable storage medium is also proposed on which such a computer program is recorded.

[0019] A portable identifier is also proposed. The portable identifier includes such storage medium. The portable identifier is configured to perform such a process. Brief description of the figures

[0020] Non-limiting examples will be described with reference to the following figures:

[0021] [Fig.1] shows a flowchart of an example of the process.

[0022] Figure [Fig.2] illustrates an example of use of the portable identifier according to the method.

[0023] Figures 3 and 4 illustrate examples of parameter adjustment Detailed description

[0024] With reference to the flowchart in [Fig. 1], a method is proposed for using a wearable identifier configured to communicate using one or more communication protocols with a vehicle system that has registered the wearable identifier. The wearable identifier includes a power source. The method comprises, for at least one communication protocol, the following four steps using the wearable identifier. The first step is a detection S10 of a loss of communication using the communication protocol with the system. The second step is a determination S20 of the number of steps taken by a user wearing the wearable identifier between the detected loss of communication and the deactivation of the wearable identifier. The third step is, after reactivation of the identifier, a monitoring S30 of the number of steps taken by the user wearing the wearable identifier.The fourth step is an S40 communication trigger using the communication protocol with the system when the monitored number of steps becomes greater than the determined number of steps.

[0025] The method provides improved use of the portable identifier.

[0026] Indeed, the method allows, for each of the at least one communication protocol, the initiation of communication using that protocol only when the wearable identifier is again within the range in which the communication protocol can be used. This avoids having to make unsuccessful communication attempts while the user approaches the vehicle, thus improving the lifespan of the wearable identifier's power source.

[0027] In particular, the method is especially precise and reliable. Indeed, counting the number of steps allows for an objective measurement of how far the user has moved from the vehicle after the loss of communication when they exited it, and the number of steps counted then makes it possible to know, when the user returns to the vehicle, how many steps they must take before the communication protocol can be used again. Counting the number of steps is reliable given that the user generally takes the same route to travel from the vehicle to their destination and to return from the destination. towards the vehicle. Furthermore, the number of steps taken generally does not vary between these two moments for the same user.

[0028] On the other hand, the counting and recording of the number of steps is carried out by the wearable identifier itself. This makes the use of the wearable identifier autonomous and avoids the need for additional exchanges with the system, thus making the process particularly efficient.

[0029] Furthermore, the method adapts to a wide range of situations (for example, parking the vehicle at work, at home, or while shopping). Indeed, determining the number of steps taken by the user allows for consideration of the fact that this number of steps may vary in each situation. When the user returns to the vehicle, the method enables the communication to be triggered at the appropriate time in each situation (i.e., taking into account the number of steps determined when the user previously left the vehicle, and therefore the specific situation). In particular, the method allows for a different number of steps to be considered for each communication protocol.

[0030] The one or more communication protocols may include a UWB (Ultra Wide Band) communication protocol and a BLE (Bluetooth Low Energy) communication protocol. The method includes performing steps S10 to S40 for each of these UWB and BLE protocols. For example, the method may first include S10 communication loss detection using the UWB protocol, and then, in a second step, S10 communication loss detection using the BLE protocol (the UWB protocol having a more limited range than BLE). The number of steps determined in step S20 may differ for each communication protocol.For example, the number of steps determined for the UWB protocol may be less than the number of steps determined for the BLE protocol (the BLE protocol having a greater range than the UWB protocol). The identifier can record a respective number of steps for each protocol. The respective number of steps can be the number of steps determined between the detected loss of communication for the protocol and the deactivation of the portable identifier.

[0031] Steps S10 to S40 are executed by the portable identifier for each protocol, for example in parallel. Information is now provided on the execution of steps S10 to S40 for a particular communication protocol (e.g., BLE or UWB). However, this information can be applied to any of the communication protocols for which the method includes the execution of these steps.

[0032] Steps S10 to S40 are executed by the portable identifier. For example, The portable identifier may include a processor and memory on which the portable identifier computer program is stored. This computer program may include instructions which, when executed by the portable identifier's processor, cause it to implement steps S10 to S40.

[0033] The method may include performing steps S10 and S20 while the user travels to and from a destination (e.g., their home, office, hotel, or business such as a shop or restaurant). The user's route during the outbound and return legs of this journey may be substantially the same. The method may include performing steps S10 and S20 while the user is traveling to the destination, i.e., after the user has left the vehicle. The method may also include performing steps S10 and S20 while the user is traveling back to the vehicle.

[0034] In examples, the method may include repeating steps S10 to S40 for each protocol on each round trip. For example, the method may include repeating steps S10 to S40 for each protocol on each of the vehicle-home, vehicle-work, vehicle-hotel, and / or vehicle-shop trips made by the user carrying the portable identifier.

[0035] Communication loss can occur while the user is traveling to the destination. For example, each communication protocol can be used within a certain perimeter around the vehicle, and communication loss can occur when the user leaves this perimeter. The method can perform S10 communication loss detection at this time.

[0036] The deactivation of the wearable identifier can occur at the end of the outbound journey, i.e., when the user arrives at the destination. For example, deactivation can take place after the user has placed the wearable identifier (e.g., on a chest of drawers or a desk), or after the user has sat down (e.g., at their desk or at a restaurant table). The wearable identifier can be deactivated in any way. For example, deactivation can include detecting the absence of movement of the wearable identifier (e.g., for at least a predetermined period) and then, in response to this detection, stopping the operation of all the wearable identifier's functions (e.g., except for a standby function). The absence of movement can be detected by the motion sensor.Alternatively, deactivation may include the user pressing a stop button located on the portable identifier (the identifier being configured to deactivate itself in response to this press). button). The method can perform the S20 determination at the end of the outward journey, for example just after the portable identifier has stopped moving and just before it has been deactivated.

[0037] Reactivation of the portable identifier can occur after its deactivation. Reactivation can also occur when the portable identifier resumes movement (after movement has stopped at the time of deactivation), i.e., at the beginning of the return journey. Reactivation can also occur after a certain period of time has elapsed since the identification was deactivated. This period may correspond to the user's stay at the destination before the user uses the vehicle again and makes the return journey. The method can perform S30 monitoring during this return journey. Reactivation of the portable identifier can be carried out in any manner.For example, reactivation could involve detecting movement of the wearable device (for example, for at least a predetermined period) and then, in response to this detection, activating all of the wearable device's functions (and, for example, deactivating the sleep function). The motion detection could be measured by the motion sensor. Alternatively, reactivation could involve the user pressing a power button located on the wearable device (the device being configured to reactivate itself in response to this button press).

[0038] The method can execute the S40 trigger after the user enters the perimeter around the vehicle in which the communication protocol can run. For example, the method can execute the S40 trigger immediately after the user enters the perimeter, or after the user has taken a few steps within the perimeter.

[0039] For each protocol, communication refers to the exchange, for example periodic, of signals between the wearable device and the vehicle system according to the communication protocol. Loss of communication refers to a cessation of these exchanges. Before step S10, the method may include a preliminary phase comprising, for example periodically, exchanges using the communication protocol between the wearable device and the vehicle system. The wearable device may still be within the vehicle's range, allowing such communication with the vehicle system. For example, the user may still be inside the vehicle, or may still be a few meters away from the vehicle. Each exchange may include the transmission of a signal by one of the wearable device and the system, and the reception of this signal by the other of the wearable device and the system.

[0040] At the time of step S10, this communication is lost. This means that one or more signals fail to be exchanged between the handheld device and the The system (for example, due to the distance between them, or the presence of a wall preventing signal exchange) may experience a loss of communication. This loss can include the transmission of one or more signals by one of the wearable devices and the system, and the other of the wearable devices and the system not receiving (or receiving with too low a signal strength) those same signals. The lack of reception can be caused by an excessive distance between the system and the wearable device, or by the presence of objects (such as a wall) preventing signal propagation between the system and the wearable device.

[0041] S10 communication loss detection can be performed in any manner. S10 detection can include determining the absence of reception of a signal exchanged between the wearable device and the system. For example, S10 detection can include the wearable device sending a signal to the system, followed by the absence of reception of a return signal sent by the system (the return signal being, for example, sent in response to the signal sent by the wearable device), or reception of the signal sent by the system with an amplitude that is too low (for example, below a predetermined threshold). The amplitude can, for example, be too low for the signal to be decoded by the wearable device.

[0042] After detection S10, the method includes determining S20 the number of steps taken by the user between the detected loss of communication and the deactivation of the wearable identifier. In some examples, the wearable identifier may include a pedometer. In this case, determining the number of steps S20 may include a measurement, by the pedometer, of the number of steps taken by the user between the detected loss of communication and the deactivation of the wearable identifier.

[0043] In other examples, the wearable identifier may include a motion sensor. In this case, the S20 determination of the number of steps may include a measurement, by the motion sensor, of the movements of the wearable identifier between the detected loss of communication and the deactivation of the wearable identifier, followed by an analysis, by the wearable identifier (for example, the identifier processor), of these measured movements to deduce the number of steps taken by the user between these two times. The deduction of the number of steps based on the measured movements may be done in any way. For example, the deduction may include the recognition of regular repetitive movements in the measured movements (each repetitive movement corresponding to a step).

[0044] The method can perform the S20 determination of the number of steps while the user is moving forward. For example, the S20 determination can be done incrementally using a step counter. For example, after each step taken by the user, the S20 determination can include a determination that the user has taken a new step, and then, an addition of one step to the The process involves determining that the user has taken a new step by analyzing the movement measured by the motion sensor while the user is taking this new step, or by measuring this new step directly with the pedometer. In this case, the S20 determination may include recording a first step count corresponding to the number of steps on the counter at the time of the S10 communication loss detection, recording a second step count corresponding to the number of steps on the counter at the time the identifier is deactivated, and calculating the resulting step count by subtracting the first step count from the second. In these examples, the process may, for instance, include resetting the counter at some point during the execution of steps S10 to S40, for example, before the S10 detection, for example, when exiting the vehicle or reactivating the wearable identifier.

[0045] Alternatively, the method can perform the S20 determination of the number of steps only at the end of the forward journey. In this case, the S20 determination can, for example, include a recording of the movement measured by the motion sensor, and the method can perform the analysis based on all the movements recorded only at the end of the journey.

[0046] After the S20 determination, the method may include a record of the determined number of steps. For example, the portable identifier may include a memory, and the method may include a record of the determined number of steps on the memory.

[0047] In some examples, the user can place the wearable identifier before the S10 communication loss, that is, while still within the protocol range. In this case, the method may include stopping the step counter when the user places the identifier. For example, the method may include detecting that the wearable identifier has not moved for a predetermined time (e.g., 5 minutes), and then recording the number of steps measured by the counter. After this, the method may include stopping communication with the vehicle (the S10 communication loss occurring only at this point). The number of steps determined in step S20 between the communication stoppage and the wearable identifier deactivation will then be zero, and in this case, when the identifier is reactivated, communication will be initiated immediately after the identifier is reactivated.

[0048] S30 monitoring may include counting the number of steps taken by the user while moving forward since the reactivation of the wearable identifier. S30 monitoring may be incremental using a step counter (for example, the same counter as for S20 determination). For example, S30 monitoring may include resetting this The counter starts at the time the wearable ID is reactivated. Then, after each step taken by the user, the S30 monitoring system can determine that the user has taken a new step and add that step to the counter. The determination that the user has taken a new step can be made by analyzing the movement measured by the motion sensor while the user is taking the new step, or by measuring the new step with the pedometer.

[0049] In some examples, the S30 monitoring may also include determining the user's movement pattern. For instance, the S30 monitoring may include determining whether the user is running, walking, or stationary. This determination can be made using the pedometer, which can be configured to detect the user's movement status (i.e., whether the user is running, walking, or stationary).

[0050] The S40 trigger occurs when the monitored step count exceeds a predetermined number of steps during the outbound journey (which is, for example, stored in the memory of the wearable device). For example, the method may include, for each new step measured during S30 monitoring, a check to see if the monitored step count exceeds the predetermined number of steps during the outbound journey. When the monitored step count exceeds the predetermined number of steps during the outbound journey, the method includes the S40 trigger for communication. The S40 trigger may include attempting to establish communication between the wearable device and the system using the protocol. The S40 trigger may include sending exchanges between the wearable device and the system, in particular to allow negotiation of communication parameter(s) between the wearable device and the system.The communication triggered by these attempts may continue, for example until the user enters the vehicle or starts the vehicle (e.g., starts the vehicle's engine).

[0051] In examples, communication is triggered when the following inequality is verified:

[0052] Count _step > Not_destin - Not_loss + K.

[0053] In this inequality, `Count_steps` is the number of steps monitored at step S30. `Destination_steps` is the number of steps taken by the user between exiting the vehicle and the deactivation of the wearable identifier. `Loss_steps` is the number of steps taken by the user between exiting the vehicle and the detected loss of communication. Therefore, `Destination_steps - Loss_steps` is the number of steps determined at step S20. `Loss_steps` is a parameter dependent on the communication protocol.

[0054] The parameter Kf can be predetermined. For example, the parameter can be an integer less than or equal to 0, for example between 0 and -5, for example between 0 and -3. The parameter can depend on the protocol. For example, it can depend on the perimeter within which the communication protocol can be used (e.g., the size of that perimeter). For example, K(t) can be higher for the BLE protocol than for the UWB protocol (since the BLE protocol's perimeter is larger than the UWB protocol's). Alternatively, the parameter K(t) can be the same for all protocols. The parameter Ki allows adjusting the timing of the S40 step so that communication is established just as the user enters the perimeter. This helps improve energy utilization since this adjustment reduces the risk of communication attempts being made too early or too late.

[0055] In examples, the triggering is performed based on one or more parameters, for example, those measured and / or determined during the execution of steps S10 to S40. For example, the method may include an adjustment of the parameter K-, used in the inequality discussed previously. The method may, for example, include an adjustment of the parameter Kt based on the user's movement status detected by the pedometer. The method may perform this adjustment just before and / or while this inequality is used (i.e., by adjusting the parameter value and then verifying that the number of steps does not exceed the number of steps determined in step S20 with the inequality using the adjusted value of the parameter).

[0056] For example, the triggering can be based on the user's speed. In this case, the method may include a measurement of this speed, for example, when the user returns to the vehicle (during the execution of step S30). The measured speed may be an average speed of the user, for example, during the return journey, i.e., during monitoring S30. The measured speed may be that of the wearable identifier (this being considered equivalent to that of the user). The method may deduce this speed measurement by measuring the time between each step (for example, an average time over the first steps of the return journey). The method may, for example, consider an average distance between each step (for example, predetermined based on the user), and deduce the user's speed by dividing this average distance by the time between each step.The process can adjust the parameter based on this deduced speed. For example, the process can reduce the Ki parameter as the speed increases (and vice versa). Speed-dependent triggering contributes to improved energy source utilization because it allows for fine-tuning the communication trigger timing.

[0057] The method may, for example, use a first table in which velocity intervals are each associated with a predetermined value of Kj. The method may include a determination of the parameter K, to be used in the inequality in re looking in the first table for the predetermined value that is associated with the speed interval in which the deduced speed is found.

[0058] For example, the first table may include a first interval comprising speeds less than or equal to 1.5 meters per second associated with a value of +3 for all Ki (for example, for the UWB protocol and for the BLE protocol). The method may use this first interval when the user is walking slowly, for example, when typing a message on their phone or strolling. The first table may also include a second interval comprising speeds greater than 1.5 meters per second and less than 2.1 meters per second associated with a value of 0 for all K (for example, for the UWB protocol and for the BLE protocol). The method may use this second interval when the user is walking normally.The first table may also include a third interval comprising speeds greater than 2.1 meters per second associated with a value of -3 for all kJ (for example, for the UWB and BLE protocols). The process can use this third interval when the user is walking quickly, for example, when it is raining.

[0059] Alternatively or additionally, the triggering may be performed based on a comparison of one or more RSSI (Received Signal Strength Indication) measurements of BLE exchanges during S30 monitoring with one or more RSSI measurements of BLE exchanges at the time of the detected communication loss of each communication protocol. In this case, the one or more communication protocols may include the BLE communication protocol and the UWB communication protocol. The method may include an adjustment of the K parameter, used for the UWB protocol. For example, when the RSSI measurements of the BLE exchanges performed during S30 monitoring increase rapidly, the K parameter may be adjusted so that the UWB communication triggering begins immediately.For example, the adjusted Kt parameter can be equal to Count_steps - Desired_steps + Loss_steps, where Loss_steps is the number of steps before the UWB communication is lost. For example, the increase can be rapid when the increase in intensity between two BLE exchanges is greater than a predetermined increase value, for example, between 4 and 7 decibels. For example, the predetermined increase value might be around 6 decibels.

[0060] Alternatively or additionally, the triggering can be based on the number of steps taken by the user between exiting the vehicle and the detected loss of communication. The method can determine this number of steps at the time of step S20. The method can record this number of steps at the time of step S20 and reuse this number of steps at the time of the determination. mination of the parameter Kt at the time of step S40.

[0061] The method may, for example, use a second table in which, for each protocol, step count intervals are associated with a predetermined value. The method may include determining the parameter K, to be used in the inequality, by searching in the second table for the predetermined value of Ki that is associated, for the protocol, with the step count interval in which the number of steps taken by the user between exiting the vehicle and the detected loss of communication lies.

[0062] For example, for the UWB protocol, the second table may include a first interval comprising step counts less than or equal to 5 associated with a value of -3 for the UWB protocol parameter K. The method may use this first interval to trigger UWB communication more quickly. The second table may include a second interval comprising step counts greater than 5 and less than or equal to 9 associated with a value of 0 for the UWB protocol parameter K. The method may use this second interval to trigger UWB communication normally. The second table may include a third interval comprising step counts greater than or equal to 9 associated with a value of +3 for the UWB protocol parameter K. The method may use this third interval to trigger UWB communication later.

[0063] For the BLE protocol, the second table may include a fourth interval comprising step counts less than or equal to 10 associated with a value of -5 for the K parameter of the BLE protocol. The method may use this fourth interval to trigger BLE communication more quickly. The second table may include a fifth interval comprising step counts greater than 10 and less than or equal to 50 associated with a value of 0 for the A parameter of the UWB protocol. The method may use this fifth interval to trigger BLE communication normally. The second table may include a sixth interval comprising step counts greater than or equal to 50 associated with a value of +5 for the K parameter of the BLE protocol. The method may use this sixth interval to trigger BLE communication later.

[0064] The portable identifier can be compact. The identifier can be a key fob or a smartphone. The identifier is worn by the vehicle user (e.g., the driver). The identifier can be configured to remotely control the execution of one or more vehicle functions (e.g., opening doors and / or the trunk, starting the vehicle, and / or locking the vehicle). For this purpose, the identifier can include buttons controlling these different functions. The identifier can be configured to detect movement of the identifier (and / or the absence of movement). For this purpose, the identifier It may include a motion sensor. The identifier can also be configured to measure the number of steps taken by the wearer. For this purpose, the identifier may include a pedometer.

[0065] In examples, the wearable identifier may include a UWB component, a BLE component, and internal communication between the UWB component and the BLE component. The UWB component (for example, a UWB chip) may be configured to program UWB exchanges. The UWB component may be connected to an antenna for sending UWB signals for UWB exchanges. The BLE component (for example, a BLE chip) may be configured to program BLE exchanges. The UWB component may be connected to an antenna for sending BLE signals for BLE exchanges. The BLE component may be the so-called "master" component, and the UWB component may be controlled by the so-called "master" component.

[0066] In examples, the communication triggering includes, for each communication protocol, the sending of a wake-up signal by the microcontroller to the respective component of the communication protocol. For the UWB protocol, the UWB communication triggering may also include configuring UWB communication with negotiated session parameters using BLE communication (which is already triggered at that time). The UWB communication triggering may also include an instruction to start UWB communication after the elapsed time of a predetermined duration, for example, a duration of Y milliseconds. The method may include determining the duration Y based on the number of steps remaining to enter the UWB perimeter at the time of the session parameter negotiation.BLE and UWB communications may be governed by the CCC standard (acronym for "China Compulsory Product Certification"), for example the standard "CCC-TS-101-Digital-Key-R3-1.2.0-approved".

[0067] The electrical power source can be a battery. For example, the electrical power source can be a button cell. The electrical power source can be rechargeable (for example, type VL3032), or alternatively, non-rechargeable (non-rechargeable battery). In some examples, the battery can have a diameter of less than 25 millimeters, for example, approximately 20 millimeters. Alternatively or additionally, the battery can have a height of less than 8 millimeters, for example, less than 6 millimeters. For example, the battery can have a height of approximately 3.2 millimeters. For example, the battery can be a CR2250, CR2577, or CR2032 button cell.

[0068] The vehicle can be any type of vehicle configured to understand such a system having recorded the portable identifier. For example, the vehicle can be a car, a truck, or a motorcycle. The system can have recorded one or more other identifiers. portable identifiers. In this case, one or more other portable identifiers can also be used according to the same usage procedure. For example, one or more other portable identifiers may belong to one or more other vehicle users and can be configured to execute the procedure when these other users make round trips from the vehicle to one or more destination locations.

[0069] The BLE communication protocol can be used as a communication protocol with the vehicle. The UWB communication protocol can be used to measure the distance between the identifier and the vehicle. Data can be contained within the UWB exchanges to secure the communication and measure the distance by measuring the time taken for the message to arrive.

[0070] Examples will now be described with reference to Figures 2 to 4.

[0071] Figure 2 illustrates an example of using the wearable identifier according to the method. In this example, the method is performed while the user makes a round trip from their vehicle 100 to their home 200 along the route 300 (which is substantially the same for both the outbound and return journeys). The wearable identifier is configured to communicate with the vehicle system using a BLE communication protocol and a UWB communication protocol. The UWB communication protocol is used within a first perimeter 110 around the vehicle. The BLE communication protocol is used within a second perimeter 120 around the vehicle (larger than the first 110). For the UWB protocol, communication is lost when the user leaves the first perimeter 110, i.e., at point 111 on the route 300.For the BLE protocol, the loss of communication occurs when the user leaves the second perimeter 120, that is, at point 121 on path 300.

[0072] The method comprises, using a portable identifier, the following four steps for each of the two communication protocols BLE and UWB. The first two steps are performed after the user leaves their vehicle 100 and proceeds to their home 200 along route 300. The first step is a communication loss detection using the communication protocol with the system. For the UWB protocol, the communication loss occurs when the user leaves the first perimeter 110, i.e., at point 111 on route 300. For the BLE protocol, the communication loss occurs when the user leaves the second perimeter 120, i.e., at point 121 on route 300.

[0073] For each protocol, the second step is a determination of the number of steps taken by a user wearing the wearable identifier between the detected loss of communication and the deactivation of the wearable identifier. This number of steps is, for the UWB protocol, the number of steps between point 111 and home 200, and for the BLE protocol, the number of steps between point 121 and home 200.

[0074] The third step is performed after the identifier has been reactivated. For example, the user decides to return to their vehicle 300 and therefore takes route 300 again. The user then enters the identifier, resulting in its reactivation and the start of the third step. The third step involves monitoring the number of steps taken by the user wearing the wearable identifier while making this return journey.

[0075] The fourth step is a communication trigger using the communication protocol with the system when the monitored number of steps exceeds the predetermined number of steps. For the BLE protocol, the BLE communication trigger occurs at point 111 (at this point, the monitored number of steps corresponds to that determined during the second step). Similarly, for the UWB protocol, the UWB communication trigger occurs at point 121.

[0076] The method provides improved use of the wearable device. Specifically, the method allows communication to be initiated for each protocol only when the wearable device is again within the range in which the communication protocol can be used (110 for the UWB protocol and 120 for the BLE protocol). This avoids the need for unsuccessful communication attempts while the user approaches the vehicle, thus improving the battery life of the wearable device. This is made possible by counting the number of steps, which provides an objective measurement of how far the user has moved from the vehicle after the communication is lost.

[0077] An example of a situation is described in this example (vehicle-to-home journey), but the method can be adapted to a wide range of situations (for example, vehicle-to-work or vehicle-to-shop journey). For each of these other situations, the method allows, in each case, the communication to be triggered at the right time.

[0078] Figure 3 illustrates a first example of adjusting the parameter K. In this first example, vehicle 101 is parked in a garage near the house, and the loss of UWB and BLE communications (i.e., UWB and BLE signals) occurs after only a few steps. Indeed, when the user leaves the garage, he or she leaves the 410 perimeter of the UWB protocol and the 420 perimeter of the BLE protocol.

[0079] In this first example, for each protocol, the triggering can be performed based on the number of steps taken by the user between exiting the vehicle and the detected loss of communication. The method can determine this number of steps at step S20. The method can record this number of steps at step S20 and reuse this number of steps when determining the parameter Kf at step S40.

[0080] When UWB communication is lost after a number of steps less than or equal to At 5 steps, the Kt parameter used for UWB communication can be set to -3. This allows communication to be initiated more quickly. When UWB communication is lost after a step count greater than 5 and less than or equal to 9, the K{ parameter used for UWB communication can be set to 0. This allows communication to be initiated normally. When UWB communication is lost after a step count greater than 9, the K{ parameter used for UWB communication can be set to -3. This allows communication to be initiated later.

[0081] In the present situation of [Fig. 3], this adjustment is particularly suitable. Indeed, it allows for faster triggering of UWB and BLE communications because the number of steps taken by the user is low, as the garage is close to the house, which is particularly efficient.

[0082] Figure 4 illustrates a second example of adjusting the parameter K. In this second example, the vehicle 102 is parked in a garage or parking lot, and UWB communication is lost when the user leaves the garage. BLE communication, however, remains active when the user leaves the garage. This is because when the user leaves the garage, they exit the UWB protocol perimeter 510 but not the BLE protocol perimeter 520.

[0083] In this second example, the method includes an adjustment of the Ki parameter used for the UWB protocol. When the RSSI measurements of the BLE exchanges performed during S30 monitoring increase rapidly, the Ki parameter is adjusted so that the UWB communication is triggered immediately. In particular, when the increase in intensity between two BLE exchanges is greater than 6 decibels, the Ki parameter is adjusted to be equal to Count _steps - Steps _destination + Steps _loss, with Steps _loss the number of steps before the loss of UWB communication.

[0084] In the present situation of [Fig. 4], this adjustment is particularly suitable. Indeed, it allows for immediate triggering of UWB communications because the increase in intensity between two BLE exchanges will be greater than 6 decibels, which is particularly effective.

Claims

1. Demands A method for using a portable identifier configured to communicate using one or more communication protocols with a vehicle system that has registered the portable identifier, the portable identifier including a source of electrical power, the method comprising using the portable identifier, for at least one communication protocol: • a detection (S 10) of loss of communication using the communication protocol with the system; • a determination (S20) of the number of steps taken by a user wearing the wearable identifier between the detected loss of communication and a deactivation of the wearable identifier; • after reactivation of the wearable identifier, monitoring (S30) of the number of steps taken by the user wearing the wearable identifier; and • a communication trigger (S40) using the communication protocol with the system when the number of monitored steps becomes greater than the number of determined steps.

2. A method according to claim 1, wherein, for each communication protocol, communication is triggered when the following inequality is satisfied: Count_steps > Step_destination - Step_loss + K, where Count_steps is the number of steps monitored, Step_destination is the number of steps taken by the user between exiting the vehicle by the user and the deactivation of the portable identifier, Step_loss is the number of steps taken by the user between exiting the vehicle by the user and the detected loss of communication, and K is a parameter dependent on the communication protocol.

3. Method according to claim 1 or 2, wherein the one or more communication protocols comprise a UWB communication protocol and / or a BLE communication protocol.

4. A method according to any one of the preceding claims, wherein, for at least one protocol, the triggering is performed in function : • of the user's speed, • a comparison of one or more BLE exchange RSSI measurements determined during monitoring (S30) with one or more BLE exchange RSSI measurements at the time of the detected communication loss of each communication protocol, and / or • the number of steps taken by the user between the user exiting the vehicle and the detected loss of communication.

5. A method according to any one of the preceding claims, wherein the identifier comprises a pedometer, the determination of the number of steps and / or the monitoring of the number of steps comprising one or more measurements of the number of steps by the pedometer.

6. A method according to any one of the preceding claims, wherein the identifier comprises a microcontroller and, for each communication protocol, a respective component, the communication triggering comprising, for each communication protocol, sending a wake-up signal by the microcontroller to the respective component of the communication protocol.

7. A method according to any one of the preceding claims, wherein the electrical energy source is a battery, preferably a button cell, and / or having a diameter of less than 25 millimeters and / or a height of less than 8 millimeters, for example less than 6 millimeters.

8. A computer program for a portable identifier comprising instructions which, when the program is executed by a processor, cause the processor to implement the method according to any one of claims 1 to 7.

9. Computer-readable storage medium on which the computer program according to claim 8 is stored.

10. Portable identifier comprising the storage medium according to claim 9, the portable identifier being configured to perform the process according to any one of claims 1 to 7.

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