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] The present 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] Today, there are vehicles equipped with systems that have recorded one or more portable identifiers. These portable identifiers can be portable devices such as key fobs or smartphones. Each identifier includes a source of electrical energy (for example, a battery) allowing it to be portable. Such systems allow the vehicle to perform functions, such as opening the doors and / or starting the vehicle, depending on the location of the one or more portable identifiers.

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

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

[0005] To this end, a method is proposed for using a portable identifier configured to communicate using one or more communication protocols with a vehicle system having recorded the portable identifier. The portable identifier comprises an electrical energy source. The method comprises, by 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 a deactivation of the portable identifier. The third step is, after reactivation of the identifier, monitoring the number of steps taken by the user wearing the portable identifier. The fourth step is a communication trigger using the communication protocol with the system when the number of steps monitored becomes greater than the determined number of steps.

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

[0007] Count _pas > Not_desti - Not _loss + K,

[0008] in which Count_steps is the number of steps monitored, Steps_destined is the number of steps taken by the user between the user leaving the vehicle and the deactivation of the portable identifier, Steps_loss is the number of steps taken by the user between the user leaving the vehicle and the loss of communication detected 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, triggering can be performed based on:

[0011] - of a user speed,

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

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

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

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

[0016] The electrical energy source may be 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.

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

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

[0019] A portable identifier is also provided. The portable identifier comprises such a storage medium. The portable identifier is configured to perform such a method. Brief description of the figures

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

[0021] [Fig.l] shows a flowchart of an example of the method.

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

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

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

[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 triggering of communication using the communication protocol only when the portable identifier is again within the perimeter in which the communication protocol can be used. This avoids having to make unsuccessful communication attempts while the user approaches the vehicle, which improves the lifespan of the electrical energy source of the portable identifier.

[0027] In particular, the method is particularly accurate and reliable. Indeed, counting the number of steps allows an objective measurement of how far the user has moved away from the vehicle after the loss of communication when he or she left it, and the number of steps counted then makes it possible to know, when the user returns to the vehicle, how many steps the user 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 go from the vehicle to his or her destination and to return from the destination. towards the vehicle. Furthermore, the steps taken generally do not vary between these two moments for the same user.

[0028] On the other hand, the counting and recording of the number of steps are carried out by the portable identifier itself. This makes the use of the portable identifier autonomous and avoids having to carry out additional exchanges with the system, thus making the method particularly efficient.

[0029] Furthermore, the method adapts to a wide range of situations (for example, parking the vehicle at work, at home or to go shopping). Indeed, determining the number of steps taken by the user makes it possible to take into account the fact that this number of steps can vary in each situation. When the user returns to the vehicle, the method allows, in each situation, the triggering of the communication at the right time (i.e. taking into account the number of steps determined when the user previously left the vehicle, and therefore the situation). In particular, the method makes it possible to take into account a different number of steps for each communication protocol.

[0030] The one or more communication protocols may comprise a UWB (Ultra Wide Band) communication protocol and a BLE (Bluetooth Low Energy) communication protocol. The method comprises an execution of steps S10 to S40 for each of these UWB and BLE protocols. For example, the method may comprise, firstly, a detection S10 of loss of communication using the UWB protocol, then, secondly, a detection S10 of loss of communication using the BLE protocol (the UWB protocol having a more restricted range than the BLE). The number of steps determined in step S20 may be different 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 may record a respective number of steps for each protocol. The respective number of steps may be the number of steps determined between the loss of communication detected 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 (for example BLE or UWB). However, this information can apply to any of the communication protocols for which the method comprises an execution of these steps.

[0032] Steps S10 to S40 are executed by the portable identifier. For example, the portable identifier may comprise a processor and a memory on which the computer program for the portable identifier is recorded. This computer program may comprise instructions which, when executed by the processor of the portable identifier, cause the latter to implement steps S10 to S40.

[0033] The method may comprise performing steps S10 and S20 while the user is traveling a round trip from the vehicle to a destination location (e.g., his or her home, office, hotel, or business such as a store or restaurant). The user's path during the outward portion of this trip and during the return portion of this trip may be substantially the same. The method may comprise performing steps S10 and S20 while the user is traveling the outward portion of this trip, i.e., after the user has left the vehicle, and while traveling toward the destination location. The method may comprise performing steps S10 and S20 while the user is traveling the return portion of this trip, i.e., from the destination location to the vehicle.

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

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

[0036] The deactivation of the portable identifier can be carried out at the end of the outward journey, that is to say when the user arrives at the destination. For example, the deactivation can be carried out after the user has placed the portable identifier (for example on a chest of drawers or a desk), or after the user has sat down (for example at his desk or at a restaurant table). The deactivation of the portable identifier can be carried out in any manner. For example, the deactivation can comprise a detection of absence of movement of the portable identifier (for example for at least a predetermined period) and then, in response to this detection, a stopping of operation of all the functions of the portable identifier (for example except a standby function). The detection of absence of movement can be measured by the motion sensor.Alternatively, deactivation may include a user pressing a stop button located on the portable identifier (the identifier being configured to deactivate in response to the user pressing this button). button). The method may perform determination S20 at the end of the outward journey, for example just after the portable identifier is immobilized and just before it is deactivated.

[0037] The reactivation of the portable identifier can be carried out after the deactivation of the portable identifier. The reactivation of the portable identifier can be carried out at a time when the movement of the portable identifier resumes (after the movement has stopped at the time of deactivation), i.e. at the start of the return journey. The reactivation of the portable identifier can be carried out after a certain time has elapsed since the deactivation of the identification. This time can correspond to the time the user spends at the destination before the user uses the vehicle again, and therefore makes the return journey. The method can carry out the monitoring S30 during this return journey. The reactivation of the portable identifier can be carried out in any way.For example, the reactivation may include detecting motion of the portable identifier (e.g., for at least a predetermined period of time) and then, in response to this detection, turning on all functions of the portable identifier (and, for example, turning off the sleep function). The motion detection may be measured by the motion sensor. Alternatively, the reactivation may include a user pressing a power button on the portable identifier (the identifier being configured to reactivate in response to the pressing of this button).

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

[0039] For each protocol, communication means exchanges, for example periodic, of signals between the portable identifier and the vehicle system according to the communication protocol. Loss of communication means a stopping of these exchanges. Before step S10, the method may comprise a preliminary phase comprising, for example periodically, exchanges using the communication protocol between the portable identifier and the vehicle system. The portable identifier may still be within the perimeter of the vehicle allowing such communication with the vehicle system. For example, the user may still be in the vehicle, or may still be a few meters from the vehicle. Each exchange may comprise sending a signal by one of the portable identifier and the system and receiving this signal by the other of the portable identifier and the system.

[0040] At step S10, this communication is lost. This means that one or more signals fail to be exchanged between the portable device and the system (for example, due to the distance between them, or the presence of a wall preventing the exchange of signals). The loss of communication may include one or more signals being sent by one of the portable identifiers and the system and the other of the portable identifiers and the system not receiving (or receiving with too low an amplitude) these one or more signals. The lack of reception may be caused by the distance between the system and the portable identifier being too great or the presence of objects (for example, a wall) preventing the propagation of signals between the system and the portable identifier.

[0041] The detection S10 of loss of communication can be carried out in any manner. The detection S10 can comprise a determination of the absence of reception of a signal exchanged between the portable identifier and the system. For example, the detection S10 can comprise a sending of a signal by the portable identifier to the system, then, an 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 portable identifier), or a reception of the signal sent by the system with an amplitude that is too low (for example lower than a predetermined threshold). The amplitude can be for example too low for the signal to be able to be decoded by the portable identifier.

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

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

[0044] The method may perform the determination S20 of the number of steps as the user walks forward. For example, the determination S20 may be done incrementally using a counter of the number of steps measured. For example, after each step taken by the user, the determination S20 may include determining that the user has taken a new step, and then adding a 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 takes this new step, or by measuring this new step directly by the pedometer. In this case, the determination S20 can comprise a recording of a first number of steps corresponding to the number of steps of the counter at the time of the detection S10 of loss of communication, a recording of a second number of steps corresponding to the number of steps of the counter at the time of deactivation of the identifier and a calculation of the number of steps determined by subtracting the first number of steps from the second number of steps. In these examples, the method can for example comprise a resetting of the counter at a given time during the execution of steps S10 to S40, for example before the detection S10, for example at the time of leaving the vehicle or reactivation of the portable identifier.

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

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

[0047] In examples, the user may place the portable identifier before the loss of communication S10, i.e. while he or she is still within the scope of the protocol. In this case, the method may comprise stopping the step counting by the counter when the user places the identifier. For example, the method may comprise detecting that the portable identifier no longer moves for a predetermined time (e.g. 5 minutes), then recording the number of steps measured by the counter. After this, the method may comprise stopping the communication with the vehicle (the loss of communication S10 then occurring only at this moment). The number of steps determined in step S20 between the stopping of the communication and the deactivation of the portable identifier will then be zero, and in this case, at the time of reactivation of the identifier, the communication will be triggered directly after the reactivation of the identifier.

[0048] Monitoring S30 may include counting the number of steps taken by the user while moving forward since the reactivation of the portable identifier. Monitoring S30 may be done incrementally using a counter of the number of steps taken (for example the same counter as for determination S20). For example, monitoring S30 may include resetting this counter at the time of reactivation of the portable identifier. Then, after each step taken by the user, the monitoring S30 may include determining that the user has taken a new step, and then adding a step to the counter. The determination that the user has taken a new step may be made by analyzing the movement measured by the motion sensor while the user takes that new step, or by measuring that new step by the pedometer.

[0049] In examples, the monitoring S30 may also include determining how the user is moving. For example, the monitoring S30 may include determining whether the user is running, walking, or standing still. This determination may be made using the pedometer, which may be configured to detect the user's movement state (i.e., whether the user is running, walking, or standing still).

[0050] The trigger S40 is made at the moment when the number of steps monitored becomes greater than a number of steps determined during the outward journey (which is for example recorded in the memory of the portable identifier). For example, the method may comprise, at each new step measured during the monitoring S30, a check of whether the number of steps monitored becomes greater than the number of steps determined during the outward journey. When the number of steps monitored becomes greater than the number of steps determined during the outward journey, the method comprises the trigger S40 of the communication. The trigger S40 may comprise an attempt at communication between the portable identifier and the system using the protocol. The trigger S40 may comprise a sending of exchanges between the portable identifier and the system, in particular to allow a negotiation of communication parameter(s) between the portable identifier and the system.Communication triggered by these attempts may continue, for example, until the user enters the vehicle or turns on the vehicle (e.g., turns on the vehicle's engine).

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

[0052] Count_pas > Pas_desti - Pas_perte + K.

[0053] In this inequality, Count_steps is the number of steps monitored in step S30. Steps_desti is the number of steps taken by the user between the user leaving the vehicle and the deactivation of the portable identifier. Steps_loss is the number of steps taken by the user between the user leaving the vehicle and the loss of communication detected. Steps_desti- Steps_loss is therefore the number of steps determined in step S20. is a parameter dependent on the communication protocol.

[0054] The parameter Kf may be predetermined. For example, the parameter may be an integer less than or equal to 0, for example between 0 and -5, for example between 0 and -3. The parameter may depend on the protocol. For example, may depend on the perimeter in which the communication protocol can be used (e.g., the size of this perimeter). For example, K( may be greater for the BLE protocol than for the UWB protocol (the perimeter of the BLE protocol being greater than that of the UWB protocol). Alternatively, the parameter K, may be the same for all protocols. The parameter Ki makes it possible to adjust the timing of the execution of step S40 so that communication is established just as the user enters the perimeter. This contributes to improving the use of the energy source since this adjustment makes it possible to reduce the risk that communication attempts are made too early or too late.

[0055] In examples, the triggering is performed based on one or more parameters, for example measured and / or determined during the execution of steps S10 to S40. For example, the method may comprise an adjustment of the parameter K-, used in the previously discussed inequality. The method may for example comprise an adjustment of the parameter Kt based on the movement state of the user 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 become greater than the number of steps determined in step S20 with the inequality using the adjusted value of the parameter

[0056] For example, the triggering may be performed as a function of the speed of the user. In this case, the method may comprise 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 the monitoring S30. The measured speed may be that of the portable identifier (this being assimilated to that of the user). The method may deduce this speed measurement by measuring the duration between each step (for example an average duration over the first steps of the return journey). The method may for example consider an average distance between each step (for example predetermined as a function of the user), and deduce the speed of the user by dividing this average distance by the duration between each step.The method can adjust the parameter based on this inferred speed. For example, the method can reduce the Ki parameter as the speed increases (and vice versa). Speed-dependent triggering helps improve energy utilization because it allows the timing of communication triggering to be fine-tuned.

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

[0058] For example, the first table may include a first interval including 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 he or she is writing a message on his or her phone or strolling. The first table may also include a second interval including 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 above 2.1 meters per second associated with a value of -3 for all Kj (for example for the UWB protocol and for the BLE protocol). The method may 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 the S30 monitoring with one or more RSSI measurements of BLE exchanges at the time of the detected loss of communication of each communication protocol. In this case, the one or more communication protocols may comprise the BLE communication protocol and the UWB communication protocol. The method may comprise an adjustment of the parameter K, used for the UWB protocol. For example, when the RSSI measurements of the BLE exchanges performed during the S30 monitoring increase rapidly, the parameter K, may be adjusted so that the triggering of the UWB communication begins immediately.For example, the adjusted Kt parameter can be equal to Count_steps - Desti_steps + Loss_steps, with Loss_steps the number of steps before UWB communication is lost. For example, the increase can be rapid when the intensity increase between two BLE exchanges is greater than a predetermined increase value, for example between 4 and 7 decibels. For example, the predetermined increase value can be about 6 decibels.

[0060] Alternatively or additionally, the triggering may be performed based on the number of steps taken by the user between the user exiting the vehicle and the detected loss of communication. The method may determine this number of steps at the time of step S20. The method may record this number of steps at the time of step S20, and reuse this number of steps at the time of the deter- 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 each associated with a predetermined value. The method may comprise determining the parameter K, to be used in the inequality by searching in the second table the predetermined value of Ki which is associated, for the protocol, with the step count interval in which the number of steps taken by the user between the user leaving the vehicle and the detected loss of communication lies.

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

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

[0064] The portable identifier may be compact. The identifier may be a key fob or a smartphone. The identifier is carried by the user of the vehicle (e.g., the driver). The identifier may 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 may include buttons controlling these different functions. The identifier may be configured to detect movement of the identifier (and / or the absence of movement). For this purpose, the identifier may include a motion sensor. The identifier may also be configured to measure the number of steps taken by the user wearing it. For this purpose, the identifier may include a pedometer.

[0065] In examples, the portable identifier may comprise a UWB component, a BLE component and an internal communication between the UWB component and the BLE component. The UWB component (for example a UWB chip) may be configured to schedule the UWB exchanges. The UWB component may be connected to an antenna for sending the UWB signals of the UWB exchanges. The BLE component (for example a BLE chip) may be configured to schedule the BLE exchanges. The UWB component may be connected to an antenna for sending the BLE signals of the 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 comprises, for each communication protocol, a 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 comprise a configuration of the UWB communication with negotiated session parameters using the BLE communication (the latter already being triggered at this time). The UWB communication triggering may also comprise an instruction to start the UWB communication after a predetermined duration has elapsed, for example a duration of Y milliseconds. The method may comprise a determination of the duration Y based on the number of steps remaining to enter the UWB perimeter at the time of negotiation of the session parameters.BLE and UWB communications may be governed by the CCC (China Compulsory Product Certification) standard, for example the “CCC-TS-101-Digital-Key-R3-1.2.0-approved” standard.

[0067] The electrical energy source may be a battery. For example, the electrical energy source may be a button cell. The electrical energy source may be rechargeable (e.g., of the VL3032 type), or alternatively not be rechargeable (non-rechargeable battery). In examples, the battery may have a diameter of less than 25 millimeters, for example about 20 millimeters. Alternatively or additionally, the battery may have a height of less than 8 millimeters, for example less than 6 millimeters. For example, the battery may have a height of about 3.2 millimeters. For example, the battery may be a CR2250, CR2577, or CR2032 button cell.

[0068] The vehicle may be any type of vehicle configured to include such a system having recorded the portable identifier. For example, the vehicle may be a car, a truck, or a motorcycle. The system may have recorded one or more other iden portable identifiers. In this case, the one or more other portable identifiers may also be used according to the same method of use. The one or more other portable identifiers may, for example, belong to one or more other users of the vehicle, and may be configured to perform the method when these one or more other users make round trips from the vehicle to one or more destinations.

[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 in the UWB exchanges to secure the communication and to 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] [Fig. 2] illustrates an example of use of the portable identifier according to the method. In this example, the method is executed while the user makes a round trip from his vehicle 100 to his home 200 following the route 300 (which is substantially identical to the outward and return journeys). The portable identifier is configured to communicate using a BLE communication protocol and a UWB communication protocol with the vehicle system. The UWB communication protocol is used in a first perimeter 110 around the vehicle. The BLE communication protocol is used in a second perimeter 120 around the vehicle (wider than the first 110). For the UWB protocol, the loss of communication occurs at the moment 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, i.e. at point 121 on the route 300.

[0072] The method comprises, by the portable identifier, for each of the two BLE and UWB communication protocols, the following four steps. The first two steps are carried out after the user leaves his vehicle 100 and heads towards his home 200 following the route 300. The first step is a detection of loss of communication using the communication protocol with the system. For the UWB protocol, the loss of communication occurs at the moment when the user leaves the first perimeter 110, that is to say at point 111 on the route 300. For the BLE protocol, the loss of communication occurs at the moment when the user leaves the second perimeter 120, that is to say at point 121 on the route 300.

[0073] For each protocol, 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 a deactivation of the portable identifier. This number of steps is, for the UWB protocol, the number of steps between point 111 and home 200, and for BLE protocol, number of steps between point 121 and home 200.

[0074] The third step is carried out after a reactivation of the identifier. For example, the user decides to return to his vehicle 300 and therefore takes the route 300 again. The user then enters the identifier, resulting in a reactivation of the identifier and the start of the third step. The third step is a monitoring of the number of steps taken by the user wearing the portable identifier while he is making this return journey.

[0075] The fourth step is a communication trigger using the communication protocol with the system when the number of steps monitored becomes greater than the number of steps determined. For the BLE protocol, the BLE communication trigger is then carried out at point 111 (at this point, the number of steps monitored corresponding to that determined during the second step). Similarly, for the UWB protocol, the UWB communication trigger is carried out at point 121.

[0076] The method provides improved use of the portable identifier. Indeed, the method allows for each protocol the triggering of a communication only when the portable identifier is again in the perimeter in which the communication protocol can be used (110 for the UWB protocol and 120 for the BLE protocol. This avoids having to make unsuccessful communication attempts while the user approaches the vehicle, which improves the lifetime of the electrical energy source of the portable identifier. This is made possible by counting the number of steps allows an objective measurement of how far the user has moved away from the vehicle after the loss of communication.

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

[0078] [Fig. 3] illustrates a first example of adjustment of the parameter K,. In this first example, the 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 perimeter 410 of the UWB protocol and the perimeter 420 of the BLE protocol.

[0079] In this first example, for each protocol, the triggering can be performed as a function of the number of steps taken by the user between the user leaving 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 determining the parameter Kf at the time of step S40.

[0080] When UWB communication is lost after a number of steps less than or equal to to 5, then the parameter Kt used for UWB communication can be equal to -3. Thus, the communication can be triggered more quickly. When the UWB communication is lost after a number of steps greater than 5 and less than or equal to 9, then the parameter K{ used for UWB communication can be equal to 0. Thus, the communication can be triggered normally. When the UWB communication is lost after a number of steps greater than 9, then the parameter K; used for UWB communication can be equal to -3. Thus, the communication can be triggered later.

[0081] In the present situation of [Fig.3], this adjustment is particularly suitable. Indeed, it allows 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 home, which is particularly effective.

[0082] [Fig.4] illustrates a second example of adjustment of the parameter K,. In this second example, the vehicle 102 is parked in a garage or parking lot and the UWB communication is lost when the user leaves the garage. The BLE communication is still active when the user leaves the garage. Indeed, when the user leaves the garage, he or she leaves the perimeter 510 of the UWB protocol but not the perimeter 520 of the BLE protocol.

[0083] In this second example, the method comprises an adjustment of the parameter Ki used for the UWB protocol. When the RSSI measurements of the BLE exchanges carried out during the monitoring S30 increase rapidly, the parameter Ki is adjusted so that the triggering of the UWB communication begins immediately. In particular, when the increase in intensity between two BLE exchanges is greater than 6 decibels, the parameter K} is adjusted so that it is equal to Count _steps - Steps _desti + Steps _loss, with Steps _loss the number of steps before UWB communication is lost.

[0084] In the present situation of [Fig.4], this adjustment is particularly suitable. Indeed, it allows 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. Claims A method of using a portable identifier configured to communicate using one or more communication protocols with a vehicle system having registered the portable identifier, the portable identifier comprising an electrical energy source, the method comprising by the portable identifier, for at least one communication protocol: • 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 portable identifier between the detected loss of communication and a deactivation of the portable identifier; • after reactivation of the portable identifier, monitoring (S30) the number of steps taken by the user wearing the portable identifier; and • a trigger (S40) of communication using the communication protocol with the system when the number of steps monitored becomes greater than the number of steps determined.

2. Method according to claim 1, in which, for each communication protocol, the communication is triggered when the following inequality is verified: Step_Count > Step_Destination - Step_Loss + K, where Step_Count is the number of steps monitored, Step_Destination is the number of steps taken by the user between the user leaving the vehicle and the deactivation of the portable identifier, Step_Loss is the number of steps taken by the user between the user leaving the vehicle and the loss of communication detected and K, is a parameter dependent on the communication protocol.

3. The method of claim 1 or 2, wherein the one or more communication protocols comprise a UWB communication protocol and / or a BLE communication protocol.

4. Method according to any one of the preceding claims, in which, for at least one protocol, the triggering is carried out in function : • user speed, • a comparison of one or more RSSI measurements of BLE exchanges determined during monitoring (S30) with one or more RSSI measurements of BLE exchanges at the time of the detected loss of communication of each communication protocol, and / or • a number of steps taken by the user between the user leaving the vehicle and the loss of communication detected.

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

6. 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, a sending of a wake-up signal by the microcontroller to the respective component of the communication protocol.

7. Method according to any one of the preceding claims, in which the source of electrical energy 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. Computer program for a portable identifier comprising instructions which, when the program is executed by a processor, cause the latter 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 recorded.

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

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