Method and device for communication between an electronic module and a remote control device

Abstract

The invention relates to a device, a system and a method for bidirectional communication between an electronic module (3a) among a plurality of electronic modules (3a, 3b, 3c, 3d) and a remote control device (20), characterized in that it comprises: - a step of transmission by the remote control device comprising at least two switchable directional antennas (22g, 22d) having different transmission directions, through its at least two switchable directional antennas, of a command towards the plurality of electronic modules; - a step of identification of an electronic module (3a), among the plurality of electronic modules, identified as being opposite the remote control device, the communication being established only between the remote control device (20) and the electronic module (3a) among the plurality of electronic modules identified as being opposite the remote control device.Figure for abstract: Figure 4.

Description

Title of the invention: Method and device for communication between an electronic module and a remote control device Technical field

[0001] The present invention relates to a method of communication between an electronic module and a remote control device as well as a device and a communication system for implementing this device.

[0002] It relates in particular to tire pressure monitoring systems. Prior art

[0003] In an effort to improve safety, an increasing number of motor vehicles are now equipped with tire pressure monitoring systems. These systems, also known as TPMS (Tire Pressure Monitoring Systems), allow, via sensors installed on the vehicle's wheels, to know useful parameters at any time, such as, for example, the inflation pressure or the temperature of the tires. If necessary, the driver of the vehicle can thus be alerted to any situation, linked to the condition of the tires, which is likely to affect the driving conditions of the vehicle or even constitute a danger for him and any passengers. Furthermore, the information collected by these sensors can also be used by other electronic systems on board the vehicle to carry out their specific function.

[0004] TPMS are conventionally composed of two parts. On the one hand, they comprise electronic modules which are mounted, respectively, in each of the vehicle's wheels. These modules integrate, at least, an electronic circuit, a low-frequency radio wave receiver (for receiving signals whose frequency is around 125 kHz), a high-frequency radio wave transmitter (for transmitting signals whose frequency is around 315 MHz or around 434 MHz), as well as a battery to ensure their supply of electrical energy. These modules, also called "wheel units" in the following (or WU, from the English "Wheel Unit"), have the function of measuring, by means of sensors integrated into their electronic circuit, the various operating parameters of the wheel as indicated above.On the other hand, TPMS include a central unit, integrating at least one high-frequency radio wave receiver receiving the signals emitted by the wheel units (also called radio frequency or RF signals). The central unit is adapted to distinguish, analyze and exploit the information it receives in this way from each wheel unit.

[0005] Depending on the model, the wheel units can be arranged inside a tire by being fixed at the tire valve or on the inner face of its tread. In all cases, they regularly measure at least the pressure and temperature of the tire. They periodically transmit (typically about every 16 seconds) corresponding information to the central unit, accompanied by a unique wheel identifier allowing the central unit to distinguish the particular wheel from which the signals it receives come. The periodic nature of these transmissions and their frequency are directly linked to the energy consumption constraints to which the batteries integrated into the wheel units must comply.Indeed, these batteries, which must generate limited space and cost, must also make it possible to achieve, in particular to meet the expectations of customers / users, lifespans of the wheel unit (i.e. durations of use without having to carry out any replacement) of around 10 years.

[0006] As described above, communications between the wheel units and the central unit of a TPMS are carried out via radio frequency signals at determined frequencies, of the order of a few hundred megahertz (MHz).

[0007] Furthermore, the presence of a low-frequency radio wave receiver of the order of a few hundred kilohertz (also referred to as an LF signal, from the English “Low Frequency”) on each wheel unit is dedicated to diagnostic or configuration / learning operations of the wheel unit concerned. Indeed, an external tool can be used in a maintenance / repair workshop, to configure the functionalities or diagnose the faults of a wheel unit, by sending it commands for this purpose using an LF signal.

[0008] The frequency bands of the signals presented in the above offer means of wireless data exchange that are reliable, secure and relatively energy-efficient. However, technological developments highlight the interest in the potential use for communication with the signal wheel units on other, higher frequency bands, to offer other “experiences” to the user. In particular, the democratization of portable and communicating user equipment, known as smart devices, such as for example smartphones, tablets or connected watches, which use ultra-high frequency (UHF) radio waves, i.e. at frequencies exceeding one gigahertz (WiFi, Bluetooth®, 4G, etc.), opens the way to very promising advanced functionalities.This makes it possible to offer, thanks to the TPMS, a greater capacity for interaction with the user, relying in particular on the two-way communications which can be established between said intelligent equipment and all or part of the wheel units of a TPMS.

[0009] The user of a vehicle could thus, for example, simply know the pressure level of each tire in real time, that is, even when he is not in his vehicle, and be alerted of the critical deflation of a tire well before the moment he accesses his vehicle to use it. This would avoid the user the inconvenience of discovering that a tire is flat at the moment he wants to use his vehicle to travel. He could therefore anticipate the necessary repair, and / or make other arrangements to be able to travel and not miss an appointment, for example.

[0010] Furthermore, the user could also access his car without a key (this is referred to as "hands-free" access) directly via his smartphone which would communicate with the vehicle for this purpose, using the communication means of the TPMS. In particular, such functionality would rely on the authentication and location of a user's smartphone via its exchanges with the wheel units of the TPMS.

[0011] Finally, the use of UHF radio waves at frequencies that allow communication between intelligent equipment and the units of a TPMS would, for pre-existing functionalities, make it possible to avoid the need for a specific vehicle interface (visual or audio) in order to communicate useful information to the user on his smartphone. Furthermore, it would also allow the creation of new functionalities based on direct interactivity between this intelligent equipment of the user and the vehicle.

[0012] In summary, the use of UHF radio waves at frequencies in the gigahertz range to exchange data wirelessly with the wheel units of a TPMS thus leads to an improved “user experience”. Finally, the type of signal used to establish such wireless communication is chosen both to offer sufficiently strong security guarantees (with regard to legal standards) and to offer a range suitable for the data exchanges concerned.

[0013] One approach envisaged consists of using UHF signal transmitters / receivers at a frequency higher than one gigahertz, directly implanted in the wheel units of a TPMS. This approach has, for example, already been considered with the use of a low-energy Bluetooth® signal at 2.4 GHz, also known as a BLE signal (from the English “Bluetooth® Low Energy”). This makes it possible, first of all, to transmit directly to the user, on his smart equipment, relevant information on the state of the tires which comes from the measurements of the wheel unit sensors. It also makes it possible, by using the ability of the wheel units to detect such signals in their environment, to precisely locate a user and, if necessary, to know his movement in this environment (in other words in the immediate environment, around the vehicle itself).Such location proves useful for achieving a "hands-free" vehicle access function that is . responsive and efficient, for example by making it possible to detect the side from which the user is approaching the vehicle and to perform actions accordingly. Finally, the integration of UHF transmitters / receivers for such signals in the wheel units and / or in the central unit of a TPMS is part of an overall objective of evolving towards functionally richer future systems. UHF radio signals can in fact be used both for inter-unit communications within the TPMS and to carry out their configuration, diagnostics or for other future functionalities, which are / will be specific to the function of TPMS.

[0014] This approach, however, has, as it stands, a significant limitation to its effective implementation, and in particular concerning the integration of a UHF receiver in the wheel unit, replacing the low-frequency LF radio wave receiver. Indeed, in the context of the use of an external tool in production or in a maintenance / repair workshop, to configure the functionalities or diagnose the failures of a wheel unit, the presence of the LF receiver in the wheel unit allows the tool to send it commands for this purpose using an LF signal. Due to the LF communication which is established between the tool and the wheel unit, a command sent by the tool is only received by the wheel unit closest to the tool.Thus, by positioning the tool opposite a designated wheel unit, and possibly with an adjustment of the tool's transmission power, it is possible to diagnose or configure a wheel unit, without requiring any prior identification of the wheel unit to establish this LF communication.

[0015] On the other hand, the integration of a UHF receiver in the wheel unit to replace an LF receiver implies that the tool then no longer has the assurance of communicating only with the nearest wheel unit, the UHF receivers of distant wheel units also being able to receive a command transmitted by the tool and respond to it. In this case, varying the transmission power is not sufficient to discriminate a wheel unit.

[0016] [Fig.l] represents a graph of reception powers of signals received by a tool with the time in ms on the abscissa and the power received in dBM on the ordinate. The graph therefore illustrates the reception powers by the tool of four response signals emitted by four wheel units following an RF command emitted by the tool with a fixed power, the responses ranging between -50dBM and -110dBM. The wheel units are arranged at different distances from the tool and the signal power received by the tool, also known by the acronym "RSSI" for "Received Signal Strength Indication" in English, depends in particular on the distance between the transmitter and the receiver. This graph shows in particular the overlaps existing between the different responses received by the tool so that there is a risk of possible confusion between the different wheel units due to the sensitivity levels of the signal of each wheel unit. This overlap is due in particular to the particular configuration of UHF bidirectional communication, in particular Bluetooth® low energy (known as BLE). Indeed, the communication uses, one after the other, a plurality of UHF channels, for example three UHF channels, operating at different frequencies. Since the RSSI levels are not the same depending on the channels, this contributes to this "fog" illustrated in [Fig. 1].

[0017] Intervening to vary only the power of the RF command emitted by the tool would not be sufficient to discriminate the UHF responses received, this being all the more true taking into account the environment in which these RF-UHF communications take place which is not favorable (in particular due to the existence of reflections for example).

[0018] There is therefore a need to be able to identify, easily and unambiguously, the wheel unit equipped with a UHF transmitter closest to an RF control tool in the context of RF-UHF communication. Statement of the invention

[0019] An aim of the present invention is therefore to enable the identification of a given wheel unit, in particular by a diagnostic or configuration tool, with a view to communication with said tool.

[0020] According to the invention, this aim is achieved by means of a communication method according to a communication protocol allowing a bidirectional exchange of data over a short distance using ultra-high frequency radio waves between an electronic module among a plurality of electronic modules and a remote control device, remarkable in that it comprises: - a step of transmission by the remote control device comprising at least two switchable directional antennas having different transmission directions, through its at least two switchable directional antennas, of a command towards the plurality of electronic modules; a step of identifying an electronic module, among the plurality of electronic modules, identified as being in front of the remote control device, communication being established only between the remote control device distance and the electronic module among the plurality of electronic modules identified as being opposite the remote control device.

[0021] The present invention therefore makes it possible, by reducing the dispersion of the received power measurements, and by adding an additional source of information (such as the direction of the transmitted signal), to reject with a significant margin, the distant wheel units, and thus unambiguously identify a given wheel unit (namely the one in front of the tool).

[0022] According to an advantageous exemplary embodiment, the communication method comprises a preliminary mapping step according to which: - the remote control device emits a basic signaling message, - upon detection by an electronic module of a basic signaling message emitted by the remote control device, the electronic module emits a standard response message, - the remote control device thus having knowledge of the electronic modules located nearby.

[0023] According to another advantageous exemplary embodiment, the standard response message sent by the electronic module upon detection of a basic signaling message sent by the remote control device comprises an identifier of the electronic module.

[0024] According to an advantageous exemplary embodiment, the step of identifying the electronic module opposite the remote control device comprises the following steps: - the remote control device comprising at least two switchable directional antennas having different emission directions emits, through its at least two switchable directional antennas, a transmission command towards the plurality of electronic modules; - the plurality of electronic modules respond to this same command issued by the remote control device by emitting a response signal; - an electronic module is identified as being opposite the remote control device if: * a power level of the response signals associated with this electronic module and received by each of the at least two switchable directional antennas of the remote control device is greater than a first predefined threshold; and * a difference in power levels of the response signals associated with this electronic module and received by the at least two switchable directional antennas of the remote control device is less than a second predefined threshold.

[0025] According to another example of implementation, the step of identifying the electronic module opposite the remote control device comprises the following steps: - the remote control device comprising at least two switchable directional antennas having different transmission directions transmits a transmission command towards the plurality of electronic modules in the form of a plurality of frames through its at least two switchable directional antennas, each of the transmitted frames comprising an identifier of the switchable directional antenna used; - an electronic module is identified as being opposite the remote control device if: * a reception power level by the electronic module of the frames transmitted by each of the at least two switchable directional antennas of the remote control device is greater than a first predefined threshold; and * a difference in reception power levels by the electronic module of the frames transmitted by each of the at least two switchable directional antennas of the remote control device is less than a second predefined threshold.

[0026] According to an advantageous exemplary embodiment, the method is further remarkable in that the frames transmitted by the remote control device further comprise a transmission power level of the transmission command, and in that it is also possible to determine a distance separating the remote control device and the electronic module from the transmission power level of each of the frames and from a reception power level determined by each electronic module, an electronic module being identified as being in front of the remote control device if a difference in distances determined from the frames transmitted by each of the at least two switchable directional antennas of the remote control device is less than a predefined threshold.

[0027] According to an advantageous implementation example, the power level is established on at least four signals received successively by the remote control device or the electronic modules.

[0028] According to an exemplary embodiment, the identifier of the electronic module is a specific address stored in a physical memory for controlling access to the support of the electronic module.

[0029] According to an advantageous embodiment: - when the remote control device wishes to transmit transmission commands only towards the electronic module in front of the remote control device, - and that the module opposite the remote control device is identified by its electronic module identifier, - then the subsequent transmission commands of the remote control device can be directive and include the identifier of the electronic module opposite the remote control device concerned by said transmission commands, the latter then processing these transmission commands.

[0030] The invention also relates to a remote control device for implementing a communication method according to any one of the aforementioned characteristics, remarkable in that it comprises: - at least two switchable, phase-shifted directional antennas, and - radio frequency switches.

[0031] Preferably and advantageously, the device comprises two directional antennas switchable phase shifted by an angle greater than 45°.

[0032] Advantageously, the device comprises two switchable directional antennas phase-shifted by 90°.

[0033] According to another advantageous embodiment, the device comprises two rows of at least two switchable directional antennas, the two rows of at least two switchable directional antennas being phase-shifted by an angle greater than 45° and, advantageously, the two rows of at least two switchable directional antennas are phase-shifted by 90°.

[0034] The invention also relates to a system for implementing the communication method having any one of the aforementioned characteristics, remarkable in that it comprises: - at least one remote control device having at least one of the above-mentioned characteristics, - at least two electronic modules configured for communication according to a communication protocol allowing a two-way exchange of data over short distances using ultra-high frequency radio waves.

[0035] According to an exemplary embodiment, the electronic modules are wheel units of a tire pressure monitoring system for a vehicle. Brief description of the drawings

[0036] Other characteristics and advantages of the invention will become apparent from reading the description which follows. This description is purely illustrative and must be read in conjunction with the appended drawings in which:

[0037] [Fig-1] [Fig.l] represents a graph of signal reception powers received by a tool with the time in ms on the abscissa and the power received in dBM on the ordinate.

[0038] [Fig.2] [Fig.2] is a schematic representation of a motor vehicle equipped of a tire monitoring system capable of communicating with a remote control device.

[0039] [Fig.3] [Fig.3] schematically illustrates a control device with distance according to the invention.

[0040] [Fig.4] [Fig.4] shows an example of use of the control device in a communication system according to the invention.

[0041] [Fig.5] The figure represents power readings of signals received by the device according to the invention. Description of the embodiments

[0042] [Fig.l] has already been described in the introductory part of the present application.

[0043] [Fig.2] schematically illustrates a communication system according to the invention including: - at least one remote control device 20, - four electronic modules 3a, 3b, 3c, 3d configured for communication according to a communication protocol allowing a short-distance bidirectional exchange of data using ultra-high frequency radio waves.

[0044] In a non-limiting manner, the communication system of [Fig. 2] is a system for monitoring the tires of a motor vehicle 1, the system comprising electronic modules, also called wheel units, 3a, 3b, 3c, 3d each associated with a wheel 10a, 10b, 10c, 10d of the vehicle.

[0045] In order not to unnecessarily burden the description, what will be stated for an electronic module 3 is valid for all the electronic modules of a motor vehicle which had previously been referenced 3a to 3d in [Fig.2].

[0046] The electronic modules 3 can communicate with the remote control device 20. This remote control device 20 is for example a diagnostic or configuration tool used in production or in a maintenance / repair workshop, to configure the functionalities of an electronic module, diagnose failures of an electronic module or collect data from it. This communication between the electronic modules 3 and the remote control device 20 is done according to a communication protocol allowing a bidirectional exchange of data over a short distance using ultra-high frequency radio waves, advantageously according to a communication protocol of the Bluetooth® type.

[0047] To do this, the electronic module 3 comprises a UHF module equipped with a UHF transmitter and receiver, a microprocessor and storage means. The bidirectional exchanges can concern several UHF channels differing in UHF frequency. The most frequently used UHF communication can provide three channels but there could be more. It is possible to have up to 25 UHF channels for the same UHF module equipping an electronic module 3. For example, the signaling messages use three frequency channels. The rest of the channels are dedicated to the connected mode.

[0048] The remote control device 20 comprises at least two switchable directional antennas phase-shifted from each other by an angle α advantageously greater than 45° and for example 90°. More precisely, it is the directions of the radiation lobes of the antennas which are at 90° to each other. The remote control device 20 comprises radiofrequency switches known per se.

[0049] Advantageously, the remote control device 20 comprises two rows 21 of at least two phase-shifted switchable directional antennas 22. Advantageously, the two rows 21 of at least two switchable directional antennas 22 are out of phase by an angle a greater than 45°.

[0050] With reference to [Fig. 3], the remote control device 20 comprises two rows 21 of three switchable directional antennas 22. The two rows 21 of three switchable directional antennas 22 are phase-shifted by an angle a of 90°, one row 21 of antennas 22 being oriented to the left of the remote control device 20 and one row 21 of antennas 22 being oriented to the right of the remote control device 20.

[0051] The communication method according to the invention will now be described.

[0052] In [Fig.4] is illustrated a communication system according to the invention comprising a remote control device 20 comprising two rows of three antennas 22, and four electronic modules 3a, 3b, 3c, 3d positioned in the close environment of the remote control device 20.

[0053] The communication method according to the invention comprises an optional preliminary mapping step allowing the remote control device 20 to become aware of the electronic modules 3a, 3b, 3c, 3d located in its immediate environment.

[0054] To carry out this mapping step, the remote control device 20 sends a basic signaling message. The basic signaling messages sent by the remote control device 20 have the advantage of being simple, of not containing data, and may not be addressed, except in special cases, to a specific electronic module, serving only to signal the presence of the remote control device 20 to the electronic modules present in its environment.

[0055] When an electronic module 3a, 3b, 3c, 3d detects the basic signaling message transmitted by the remote control device 20, the electronic module 3a, 3b, 3c, 3d transmits a standard response message. This standard response message does not contain specific data but its sending by the electronic module 3a, 3b, 3c, 3d and its reception by the remote control device 20 is interpreted by the latter as information of presence in the close environment of the remote control device 20. Advantageously, the standard response message transmitted by the electronic module 3a, 3b, 3c, 3d upon detection of a basic signaling message transmitted by the remote control device 20 comprises an identifier of the electronic module 3a, 3b, 3c, 3d.This identifier of the electronic module 3a, 3b, 3c, 3d is for example a specific address stored in a physical memory controlling access to the support of the electronic module (also called “Media Access Control” in English, or “MAC” for short).

[0056] When an operator wishes to configure an electronic module of interest 3a or retrieve data from said electronic module 3a with a view, for example, to carrying out a diagnosis, it positions itself near said electronic module 3a and directs the remote control device 20 facing said electronic module 3a.

[0057] During a transmission step, the remote control device 20 transmits, through its antennas 22, a command towards the plurality of electronic modules 3a, 3b, 3c, 3d present in the environment of the remote control device 20.

[0058] During an identification step, the electronic module of interest 3a identifies itself or is identified as being opposite the remote control device 20, which makes it possible to establish communication between the remote control device 20 and the electronic module of interest 3a only, the other electronic modules 3b, 3c, 3d present in the environment of the remote control device 20 then being ignored.

[0059] According to an exemplary implementation of the method according to the invention, the step of identifying the electronic module 3a of interest located opposite the remote control device 20 comprises the following sub-steps: - the remote control device 20 transmits, through its switchable directional antennas 22, a transmission command towards the plurality of electronic modules 3a, 3b, 3c, 3d located in its environment; - the electronic modules 3a, 3b, 3c, 3d respond to this same command issued by the remote control device 20 by emitting a response signal; - an electronic module 3a is identified as being opposite the remote control device if: * a power level of the response signals associated with this electronic module 3a and received by each of the switchable directional antennas 22 of the remote control device 20 is greater than a first predefined threshold SI; and * a difference in power levels of the response signals associated with this electronic module 3a and received by the switchable directional antennas 22 of the remote control device 20 is less than a second predefined threshold S2.

[0060] [Fig.5] illustrates two readings of signal power (RSSI) received by the remote control device 20 as a function of time (t). The reading 22G illustrated on the left portion of [Fig. 5] illustrates the signal power received by an antenna 22g disposed on the left portion of the remote control device 20 and the reading 22D illustrated on the right portion of [Fig. 5] illustrates the signal power received by an antenna 22d disposed on the right portion of the remote control device 20. Alternatively, the readings may illustrate averages of powers received across all the antennas of a left or right row 21 of antennas 22 of the remote control device 20.

[0061] When the remote control device 20 is pointed towards the electronic module of interest 3a, due to the 90° phase shift between the rows 21 of antennas 22, an angle [3 of the order of 45° is formed between each antenna 22 of each row 21 of antennas and the electronic module 3a facing the control device 20. This topology makes it possible to scan both the front zone of the control device 20 (visible by each antenna 22), but also, depending on the antenna 22 considered, the zone to the left and to the right of the control device 20. Thus, if the electronic module 3a is facing the control device 20, a field measurement seen by the antennas 22 of the two rows 21 is in this case substantially equivalent, even if the control device 20 is not pointed directly at the electronic module 3a. The other electronic modules 3b, 3c, 3d present in the environment can also be detected by the control device 20 with a strong field level, but only on one of the rows of antennas, which allows unequivocal discrimination of the electronic module of interest 3a.

[0062] In particular, in [Fig.5], the electronic module 3a is the only module of which: * the response signal power level received by each or the switchable directional antennas 22g and 22d of the remote control device 20 is greater than a first predefined threshold SI, for example -70dB (here -65dB on the left reading 22G and -68dB on the right reading 22D); and * a difference in power levels of the response signals received by the switchable directional antennas 22g and 22d of the remote control device 20 is less than a second predefined threshold S2, for example 5dB in absolute value (here 3dB difference in absolute value between the left reading 22G and the right reading 22D).

[0063] Advantageously, when the remote control device 20 transmits the transmission command, it transmits a plurality of frames through its switchable directional antennas 22, each of the transmitted frames comprising an identifier of the switchable directional antenna used 22 for this transmission. In this case, an electronic module 3a is identified as being in front of the remote control device 20 if: * a reception power level by the electronic module 3a of the frames transmitted by each of the switchable directional antennas 22 is greater than a first predefined threshold S' 1; and * a difference in reception power levels by the electronic module 3a of the frames transmitted by each of the switchable directional antennas 22 is less than a second predefined threshold S'2.

[0064] According to an exemplary implementation, the frames transmitted by the remote control device 20 also include information on the transmission power level of the transmission command. It is then possible to determine a distance separating the remote control device 20 and the electronic module 3a, 3b, 3c, 3d from of the transmission power level of each of the frames and of a reception power level determined by each electronic module 3a, 3b, 3c, 3d. Thus, an electronic module 3a is identified as being in front of the remote control device 20 if a difference in distances determined from the frames transmitted by each of the switchable directional antennas 22 of the remote control device 20 is less than a predefined threshold S3.

[0065] Advantageously, whatever the embodiment implemented, the power level is for example established on at least four signals received successively by the remote control device 20 or the electronic modules 3a, 3b, 3c, 3d. Indeed, in a communication protocol allowing a bidirectional exchange of data at short distance using ultra-high frequency radio waves, for example of the Bluetooth® type, the messages are transmitted are transmitted on several frequency channels, generally on three frequency channels. This has the consequence of generating noise during the various exchanges between the remote control device 20 and the electronic modules 3a, 3b, 3c, 3d. In this way, establishing the power level on several signals received successively makes it possible to reduce the impact of this noise.

[0066] The present invention thus allows a remote control device 20 to enter into communication with an electronic module of interest in a simple, rapid and efficient manner. In particular, when the remote control device 20 wishes to transmit transmission commands only towards the electronic module 3a of interest located opposite the remote control device 20, and the electronic module 3a opposite the remote control device 20 is identified by its electronic module identifier, then the subsequent transmission commands from the remote control device 20 may be directive and include the identifier of the electronic module 3a concerned by said transmission commands, the electronic module 3a opposite the remote control device 20 then processing these transmission commands.

[0067] The present invention therefore also relates to an electronic module 3 comprising an integrated circuit specific to a microprocessor application for controlling the module provided with a microprocessor and storage means, the integrated circuit of the electronic module implementing a communication method as described previously.

[0068] The electronic module 3 also comprises an ultra-high frequency communication module according to a communication protocol for example of the Bluetooth® type, with a communication antenna for reception and transmission with communication devices according to a protocol for example of the Bluetooth® type and electronic elements integrated at least partially or not in the integrated circuit. For example, the communication module may include a microprocessor, a quartz clock and storage means.

[0069] The present invention therefore makes it possible, by reducing the dispersion of the received power measurements, and by adding an additional source of information (such as the direction of the transmitted signal), to reject with a significant margin, the remote electronic modules, and thus to unambiguously identify an electronic module of interest (namely the one opposite the remote control device).

[0070] The present invention is of remarkable interest in any field requiring localization of electronic modules 3 where only the transmitter can have directional antennas.

Claims

Claims

1. Communication method according to a communication protocol allowing a bidirectional exchange of data at short distance using ultra-high frequency radio waves between an electronic module (3a) among a plurality of electronic modules (3a, 3b, 3c, 3d) and a remote control device (20), characterized in that it comprises: - a step of transmission by the remote control device (20) comprising at least two switchable directional antennas (22) having different transmission directions, through its at least two switchable directional antennas (22), of a command towards the plurality of electronic modules (3a, 3b, 3c, 3d);- a step of identifying an electronic module (3a), among the plurality of electronic modules (3a, 3b, 3c, 3d), identified as being opposite the remote control device (20), the communication being established only between the remote control device (20) and the electronic module (3a) among the plurality of electronic modules (3a, 3b, 3c, 3d) identified as being opposite the remote control device (20).;

2. Communication method according to claim 1, characterized in that it comprises a preliminary mapping step according to which: - the remote control device (20) transmits a basic signaling message, - upon detection by an electronic module (3a, 3b, 3c, 3d) of a basic signaling message transmitted by the remote control device (20), the electronic module (3a, 3b, 3c, 3d) transmits a standard response message, the remote control device (20) thus having knowledge of the electronic modules (3a, 3b, 3c, 3d) located nearby.

3. Communication method according to claim 2, characterized in that the standard response message transmitted by the electronic module (3a, 3b, 3c, 3d) upon detection of a basic signaling message transmitted by the remote control device (20) comprises an identifier of the electronic module (3a, 3b, 3c, 3d).

4. Communication method according to any one of claims 1 to 3, characterized in that the step of identifying the electronic module (3a) opposite the remote control device (20) comprises the

5. next steps: - the remote control device (20) comprising at least two switchable directional antennas (22) having different emission directions emits, through its at least two switchable directional antennas (22), a transmission command towards the plurality of electronic modules (3a, 3b, 3c, 3d); - the plurality of electronic modules (3a, 3b, 3c, 3d) respond to this same command issued by the remote control device (20) by emitting a response signal; - an electronic module (3a) is identified as being opposite the remote control device (20) if: * a power level of the response signals associated with this electronic module (3a) and received by each of the at least two switchable directional antennas (22) of the remote control device (20) is greater than a first predefined threshold (SI); and - a difference in power levels of the response signals associated with this electronic module (3a) and received by the at least two switchable directional antennas (22) of the remote control device (20) is less than a second predefined threshold (S2). Communication method according to any one of claims 1 to 3, characterized in that the step of identifying the electronic module (3a) opposite the remote control device (20) comprises the following steps: - the remote control device (20) comprising at least two switchable directional antennas (22) having different emission directions emits a transmission command towards the plurality of electronic modules (3a, 3b, 3c, 3d) in the form of a plurality of frames through its at least two switchable directional antennas (22), each of the emitted frames comprising an identifier of the switchable directional antenna (22) used; - an electronic module (3a) is identified as being opposite the remote control device (20) if: * a reception power level by the electronic module (3a) of the frames transmitted by each of the at least two switchable directive antennas (22) of the remote control device (20) is greater than a first predefined threshold (S' 1); and * a difference in reception power levels by the electronic module (3a) of the frames transmitted by each of the at least two switchable directional antennas (22) of the remote control device (20) is less than a second predefined threshold (S'2).

6. Communication method according to claim 5, characterized in that the frames transmitted by the remote control device (20) further comprise a transmission power level of the transmission command, and in that it is also possible to determine a distance separating the remote control device (20) and the electronic module (3a, 3b, 3c, 3d) from the transmission power level of each of the frames and from a reception power level determined by each electronic module (3a, 3b, 3c, 3d), an electronic module (3a) being identified as being in front of the remote control device (20) if a difference in distances determined from the frames transmitted by each of the at least two switchable directional antennas (22) of the remote control device (20) is less than a predefined threshold (S3).

7. Communication method according to any one of claims 4 to 6, characterized in that the power level is established on at least four signals received successively by the remote control device (20) or the electronic modules (3a, 3b, 3c, 3d).

8. Communication method according to claim 3, characterized in that the identifier of the electronic module (3a, 3b, 3c, 3d) is a specific address stored in a physical memory controlling access to the support of the electronic module (3a, 3b, 3c, 3d).

9. Communication method according to one of claims 6 and 7, characterized in that: - when the remote control device (20) wishes to transmit transmission commands only in the direction of the electronic module (3a) opposite the remote control device (20), - and the electronic module (3a) opposite the remote control device (20) is identified by its electronic module identifier (3a), then the subsequent transmission commands of the remote control device (20) can be directive and include the identifier of the electronic module (3a) opposite the remote control device (20) concerned by said transmission commands, the latter then processing these transmission commands.

10. Remote control device (20) for implementing a communication method according to any one of claims 1 to 9, characterized in that it comprises: - at least two phase-shifted switchable directional antennas (22), and - radiofrequency switches.

11. Remote control device (20) according to claim 10, characterized in that it comprises two switchable directional antennas (22) phase-shifted by an angle (a) greater than 45°.

12. Remote control device (20) according to claim 12, characterized in that it comprises two switchable directional antennas (22) phase-shifted by 90°.

13. Remote control device (20) according to claim 10, characterized in that it comprises two rows (21) of at least two switchable directional antennas (22), the two rows (21) of at least two switchable directional antennas (22) being out of phase.

14. Remote control device (20) according to claim 13, characterized in that the two rows (21) of at least two switchable directional antennas (22) are phase-shifted by an angle (a) greater than 45°.

15. System for implementing the communication method according to any one of claims 1 to 9, characterized in that it comprises: - at least one remote control device (20) according to any one of claims 10 to 14, - at least two electronic modules (3a, 3b, 3c, 3d) configured for communication according to a communication protocol allowing a bidirectional exchange of data over a short distance using ultra-high frequency radio waves.

16. System according to claim 15, characterized in that the electronic modules (3a, 3b, 3c, 3d) are wheel units of a tire pressure monitoring system of a vehicle (1).

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