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 of bidirectional communication between an electronic module (3a) from 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 in the direction of the plurality of electronic modules; - a step of identification of an electronic module (3a), from among the plurality of electronic modules, identified as being in front of the remote control device, the communication being established only between the remote control device (20) and the electronic module (3a) from among the plurality of electronic modules identified as being in front of the remote control device.Figure for the abridged version: 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 communication device and system for the implementation of this device.

[0002] It relates in particular to tire pressure monitoring systems. Previous technique

[0003] In an effort to improve safety, a growing number of motor vehicles are now equipped with tire pressure monitoring systems. These systems, also known as TPMS (Tire Pressure Monitoring Systems), use sensors installed on the vehicle's wheels to provide real-time information on useful parameters such as tire pressure and temperature. If necessary, the driver can be alerted to any situation related to tire condition that could affect driving conditions or even pose a danger to the driver and any passengers. Furthermore, the information collected by these sensors can also be used by other electronic systems in the vehicle to perform their specific functions.

[0004] TPMS are typically composed of two parts. Firstly, they include electronic modules mounted in each of the vehicle's wheels. These modules integrate, at a minimum, an electronic circuit, a low-frequency radio wave receiver (for receiving signals with a frequency around 125 kHz), a high-frequency radio wave transmitter (for transmitting signals with a frequency around 315 MHz or around 434 MHz), and a battery to provide them with electrical power. These modules, also referred to as "wheel units" (or WUs, from the English "Wheel Unit"), are designed to measure, via sensors integrated into their electronic circuit, the various operating parameters of the wheel as described above.On the other hand, TPMS systems include a central unit, incorporating at least one high-frequency radio wave receiver that receives signals emitted by the wheel units (also called radio frequency or RF signals). The central unit is adapted to distinguish, analyze, and utilize 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, attached to the tire valve or to the inner surface of the tread. In all cases, they regularly measure at least the tire pressure and temperature. They periodically transmit (typically about every 16 seconds) corresponding information to the central unit, along with a unique wheel identifier that allows the central unit to distinguish the specific wheel from which the signals it receives originate. The periodic nature of these transmissions and their frequency are directly related to the energy consumption constraints of the batteries integrated into the wheel units.Indeed, these batteries, which must generate limited bulk and cost, must also allow, in particular to meet customer / user expectations, wheel unit lifespans (i.e., periods of use without having to make any replacements) of around 10 years.

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

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

[0008] The frequency bands of the signals described above offer reliable, secure, and relatively energy-efficient means of wireless data exchange. However, technological developments highlight the potential benefits of using signals on other, higher frequency bands for communication with wheel units, to offer users different "experiences." In particular, the widespread adoption of portable and communicating user devices, known as smart devices, such as smartphones, tablets, or smartwatches, which use ultra-high frequency (UHF) radio waves—that is, frequencies exceeding one gigahertz (WiFi, Bluetooth®, 4G, etc.)—is paving the way for very promising advanced functionalities.This allows, through the TPMS, a greater capacity for interaction with the user, relying in particular on the bidirectional communications that 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 The system monitors the pressure of each tire in real time, even when the driver is not in their vehicle, and alerts them to critical tire deflation well before they reach their vehicle. This would prevent the inconvenience of discovering a flat tire when they need to use their vehicle. They could then anticipate the necessary repair and / or make other arrangements to ensure they can travel and not miss an appointment, for example.

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

[0011] Finally, the use of UHF radio waves at frequencies that allow communication between smart equipment and TPMS units would, for existing functionalities, eliminate the need for a specific vehicle interface (visual or audible) to communicate useful information to the user on their smartphone. Furthermore, it would also enable the development of new functionalities based on direct interaction between this user's smart equipment and the vehicle.

[0012] In summary, the use of UHF radio waves at frequencies on the order of gigahertz 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 provide a range suitable for the data exchanges concerned.

[0013] One approach envisaged involves using UHF signal transmitters / receivers at a frequency above one gigahertz, directly integrated into the wheel units of a TPMS. This approach has, for example, already been considered with the use of a low-energy 2.4 GHz Bluetooth® signal, also known as a BLE (Bluetooth® Low Energy) signal. This firstly allows relevant information on tire condition, derived from measurements taken by the wheel unit sensors, to be transmitted directly to the user's smart device. Secondly, by using the wheel units' ability to detect such signals in their environment, it also allows for the precise location of a user and, if applicable, the determination of their movement within that environment (in other words, in the immediate vicinity of the vehicle itself).Such a location proves useful for implementing a "hands-free" vehicle access function. responsive and efficient, for example by detecting the side from which the user is approaching the vehicle and taking appropriate actions. Finally, the integration of UHF transmitters / receivers for such signals in the wheel units and / or the central unit of a TPMS is part of an overall objective of evolving towards functionally richer future systems. UHF radio signals can indeed be used both for inter-unit communication within the TPMS and for configuration, diagnostics, or other future functionalities that are / will be specific to the function of TPMS.

[0014] This approach, however, currently has a significant limitation to its effective implementation, particularly regarding the integration of a UHF receiver into the wheel unit, replacing the low-frequency (LF) radio wave receiver. Indeed, when using an external tool in production or in a maintenance / repair workshop to configure the functionalities or diagnose faults of a wheel unit, the presence of the LF receiver in the wheel unit allows the tool to send commands to it for this purpose via an LF signal. Due to the LF communication established between the tool and the wheel unit, a command issued by the tool is only received by the wheel unit closest to the tool.Thus, by positioning the tool in relation to a designated wheel unit, and possibly with an adjustment of the tool's emission 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, integrating a UHF receiver into the wheel unit instead of an LF receiver means that the tool is no longer guaranteed to communicate only with the nearest wheel unit, as UHF receivers on distant wheel units can also receive and respond to commands emitted by the tool. In this case, varying the transmission power is not sufficient to discriminate between wheel units.

[0016] Figure 1 shows a graph of the received power of signals received by a tool, with time in ms on the x-axis and received power in dBm on the y-axis. The graph illustrates the received power by the tool of four response signals emitted by four wheel units following an RF command issued by the tool with a fixed power, the responses ranging from -50 dBm to -110 dBm. The wheel units are positioned at different distances from the tool, and the received signal strength, also known by the acronym RSSI (Received Signal Strength Indication), depends in particular on the distance between the transmitter and the receiver. This graph notably shows the overlaps between the different responses received by the tool, such that there is a potential risk of confusion between the different wheel units due to the signal sensitivity levels of each. wheel unit. This overlap is primarily due to the specific configuration of UHF bidirectional communication, particularly Bluetooth® Low Energy (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 across channels, this contributes to the "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. Description of the invention

[0019] One object 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 goal is achieved through a communication method based on a communication protocol enabling bidirectional exchange of short-range data using ultra-high-frequency radio waves between an electronic module among a plurality of electronic modules and a remote control device, notable in that it comprises: - a transmission step by the remote control device comprising at least two switchable directional antennas having different emission directions, through its at least two switchable directional antennas, of a command in the direction of the plurality of electronic modules; a step of identifying an electronic module, among the plurality of electronic modules, identified as being opposite the remote control device, communication being established only between the control device and distance and the electronic module among the plurality of electronic modules identified as being in front of the remote control device.

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

[0022] According to an advantageous embodiment, the communication method comprises a preliminary mapping step in 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 being aware of the electronic modules located nearby.

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

[0024] According to an advantageous 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 in the direction of 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: * the 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 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 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 emitted frames comprising an identifier of the switchable directional antenna used; - An electronic module is identified as being opposite the remote control device if: * the 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 emitted 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 embodiment, the method is further notable in that the frames emitted by the remote control device still include a transmit power level of the transmit command, and in that it is also possible to determine a distance separating the remote control device and the electronic module from the transmit power level of each of the frames and a receive 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 emitted 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 one embodiment, the identifier of the electronic module is a specific address stored in a physical memory controlling access to the electronic module's storage medium.

[0029] According to an advantageous embodiment example: - when the remote control device wishes to send transmission commands only towards the electronic module opposite 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 further relates to a remote control device for implementing a communication method according to any one of the aforementioned characteristics, notable 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 with a 90° phase shift.

[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 further relates to a system for implementing the communication method having any one of the aforementioned characteristics, notable in that it comprises: - at least one remote control device exhibiting at least one of the aforementioned characteristics, - at least two electronic modules configured for communication according to a communication protocol allowing bidirectional exchange of data over short distances using ultra-high frequency radio waves.

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

[0036] Other features and advantages of the invention will become apparent from the following description. This description is purely illustrative and should be read in conjunction with the accompanying drawings, in which:

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

[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 represents an example of the 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 implementation methods

[0042] Fig. 1 has already been described in the introductory part of this application.

[0043] Figure 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 bidirectional exchange of data over short distances using ultra-high frequency radio waves.

[0044] Without limitation, the communication system of [Fig.2] is a tire monitoring system 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 complicate 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 shop to configure the functionalities of an electronic module, diagnose faults in an electronic module, or collect data from it. This communication between the electronic modules 3 and the remote control device 20 is carried out according to a communication protocol allowing bidirectional data exchange over short distances using ultra-high-frequency radio waves, advantageously according to a Bluetooth® type communication protocol.

[0047] The electronic module 3 comprises, for this purpose, a UHF module equipped with a UHF transmitter and receiver, a microprocessor, and storage means. Bidirectional communication can involve several UHF channels with different UHF frequencies. The most frequently used UHF communication can make three channels available, but there could be more. It is possible to have up to 25 UHF channels for a single UHF module equipping an electronic module 3. For example, signaling messages use three frequency channels. The remaining channels are dedicated to the connected mode.

[0048] The remote control device 20 comprises at least two switchable directional antennas phase-shifted relative to each other by an angle α advantageously greater than 45° and, for example, by 90°. More precisely, the directions of the radiation lobes of the antennas are at 90° to each other. The remote control device 20 comprises radio frequency 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 phase-shifted by an angle α 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 α 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] Figure 4 illustrates a communication system according to the invention comprising a remote control device 20 including two rows of three antennas 22, and four electronic modules 3a, 3b, 3c, 3d positioned in the immediate vicinity of the remote control device 20.

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

[0054] To perform this mapping step, the remote control device 20 emits a basic signaling message. The basic signaling messages sent by the remote control device 20 have the advantage of being simple, 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 emitted by the remote control device 20, the electronic module 3a, 3b, 3c, 3d sends a standard reply message. This standard reply message does not contain specific data, but its transmission by the electronic module 3a, 3b, 3c, 3d and its reception by the remote control device 20 is interpreted by the latter as information indicating presence in the immediate vicinity of the remote control device 20. Advantageously, the standard reply message emitted by the electronic module 3a, 3b, 3c, 3d upon detection of a basic signaling message emitted by the remote control device 20 includes 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 electronic module's media (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 in order, for example, to carry out a diagnostic, it positions itself near said electronic module 3a and directs the remote control device 20 in front of said electronic module 3a.

[0057] During an emission 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 in front of the remote control device 20, which allows communication to be established 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 being ignored.

[0059] According to an example of an 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 emits, through its switchable directional antennas 22, a transmission command in the direction of 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 SI threshold; 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] Figure 5 illustrates two readings of signal strength (RSSI) received by the remote control device 20 as a function of time (t). The reading 22G shown on the left side of [Fig. 5] illustrates the signal power received by an antenna 22g located on the left side of the remote control device 20 and the reading 22D shown on the right side of [Fig. 5] illustrates the signal power received by an antenna 22d located on the right side of the remote control device 20. Alternatively, the readings can illustrate average powers received on all the antennas in 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 antenna rows 21 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 area of ​​the control device 20 (visible by each antenna 22), but also, depending on the antenna 22 considered, the area to the left and 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, and this 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 antenna rows, which allows for unambiguous 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 power level of the response signal received by each or both of the switchable directional antennas 22g and 22d of the remote control device 20 is greater than a first predefined SI threshold, 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 transmit command, it transmits a plurality of frames through its switchable directional antennas 22, each of the transmitted frames including an identifier of the switchable directional antenna 22 used for that 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 emitted by each of the switchable directional antennas 22 is less than a second predefined threshold S'2.

[0064] According to one embodiment, 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 emitted by each of the switchable directional antennas 22 of the remote control device 20 is less than a predefined threshold S3.

[0065] Advantageously, regardless of the embodiment implemented, the power level is established, for example, 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 enabling bidirectional data exchange over short distances using ultra-high frequency radio waves, for example of the Bluetooth® type, messages are transmitted on several frequency channels, generally on three frequency channels. This results in the generation of noise during the various exchanges between the remote control device 20 and the electronic modules 3a, 3b, 3c, 3d. Thus, establishing the power level on several successively received signals reduces the impact of this noise.

[0066] The present invention thus enables a remote control device 20 to communicate with an electronic module of interest in a simple, fast, and efficient manner. In particular, when the remote control device 20 wishes to send 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 subsequent transmission commands from the remote control device 20 can be directional and include the identifier of the electronic module 3a concerned by said transmission commands, with 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 the control of the module equipped with a microprocessor and storage means, the integrated circuit of the electronic module implementing a communication method as described above.

[0068] The electronic module 3 also includes an ultra-high frequency communication module according to a communication protocol, for example, of the Bluetooth® type, with a communication antenna for receiving and transmitting 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. By 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 received power measurements, and by adding an additional source of information (such as the direction of the emitted signal), to reject, with a significant margin, the distant 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 the localization of electronic modules 3 where only the transmitter can have directional antennas.

Claims

Demands

1. A communication method according to a communication protocol allowing bidirectional exchange of short-range data 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 in the direction of 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), 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. A communication method according to claim 1, characterized in that it comprises a preliminary mapping step according to which: - the remote control device (20) emits a basic signaling message, - upon detection by an electronic module (3a, 3b, 3c, 3d) of a basic signaling message emitted by the remote control device (20), the electronic module (3a, 3b, 3c, 3d) emits a standard reply message, the remote control device (20) thus being aware of the electronic modules (3a, 3b, 3c, 3d) being in the vicinity.

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

4. A 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 in the direction of 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). A 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 directional 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 antennas (22) switchable directions of the remote control device (20) is less than a second predefined threshold (S'2).

6. A communication method according to claim 5, characterized in that the frames emitted by the remote control device (20) further include a transmit power level of the transmit 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 transmit power level of each of the frames and a receive power level determined by each electronic module (3a, 3b, 3c, 3d), an electronic module (3a) being identified as being opposite the remote control device (20) if a difference in distances determined from the frames emitted 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. A method of communicating 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 medium of the electronic module (3a, 3b, 3c, 3d).

9. A communication method according to any one of claims 6 and 7, characterized in that: - when the remote control device (20) wishes to send transmit commands only towards 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 subsequent transmit commands from the remote control device (20) can be directional and include the identifier of the electronic module (3a) opposite the remote control device (20) concerned by said transmit commands, the latter then processing these transmit 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-shift switchable directional antennas (22), and - radio frequency 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) with a 90° phase shift.

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 bidirectional exchange of data over short distances 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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