METHOD AND SYSTEM FOR DETECTING RECEIVERS AND ADJUSTABLE RECEIVERS

Description

TECHNICAL FIELD

[0001] The present invention relates to a method and system for detecting receivers for implementing the method, as well as to an adjustable receiver. STATE OF PRIOR ART

[0002] Items for purchase can be equipped with RFID tags or badges, for example, to reduce checkout times. The items are placed in a tray in front of or to the side of the checkout. The system identifies the items using the RFID tags and automatically issues the invoice, without the cashier having to scan each item individually. This saves time.

[0003] However, some items may not be detected by the system, which can lead to checkout errors.

[0004] When multiple receivers (or badges) are placed next to each other, as in the case of a cash register tray, reading them can be difficult, in particular because of interference and / or electromagnetic field minima. This interference is due both to the environment which can diffuse, reflect, diffract the waves, but also to the receivers themselves which, because they are also diffusers, reflect, diffuse, diffract, or even attenuate the waves.

[0005] There may also be problems with detecting receivers when they send simultaneous responses.

[0006] Document US2013 / 265140A1 provides an example of low-power radio frequency communication. Document US2005 / 190098A1 provides an example of a system and method for locating objects using RFID. DISCLOSURE STATEMENT

[0007] The present disclosure is intended to improve the detection of badges in the volume.

[0008] For this purpose, there is provided a method for detecting receivers implemented by a detection system comprising a global antenna adapted to transmit a primary wave, and a global controller connected to the global antenna, the system comprising an adjustable receiver having a receiver antenna adapted to receive the primary wave and transmit a secondary wave, the adjustable receiver having a receiver controller connected to the receiver antenna, the receiver controller being adapted to detect the primary wave received by the receiver antenna and to control the transmission of the secondary wave by the receiver antenna, the adjustable receiver having a modifiable impedance thus influencing the transmitted secondary wave, the adjustable receiver being initially in a detection mode where the adjustable receiver has a basic impedance, the method comprising: a receiver detection step in which the adjustable receiver is detected by the global controller when the global antenna receives the secondary wave transmitted by the adjustable receiver, followed by a reconfiguration step in which the global controller commands the receiver controller to switch to a cooperation mode where the impedance of the adjustable receiver is alternated between a first configuration impedance and a second configuration impedance in order to detect other receivers, the reconfiguration step being of a duration of an order of magnitude greater than a duration of each alternation of the first and second configuration impedances.

[0009] Thanks to the above provisions, the number of adjustable receivers made available to the global controller for the detection of new receivers increases as they are detected. Each time a receiver is detected, its impedance is adjusted by the global controller to a mode suitable for the detection of other receivers. The system is then able to detect more efficiently the presence of one or more receivers not previously detected, regardless of the position of said receivers, whether they are fixed or mobile.

[0010] In various embodiments of the system, one and / or the other of the following provisions may optionally be used: the base impedance is imposed by the receiver controller independently of the global controller. the first configuration impedance is the base impedance. the first configuration impedance is distant from the second configuration impedance. the first configuration impedance and the second configuration impedance are close to and on either side of the base impedance in the complex plane. the tunable receiver is a first tunable receiver, the receiver antenna is a first receiver antenna, the primary wave is a first primary wave, the secondary wave is a first secondary wave, the receiver controller is a first receiver controller, the base impedance is a first base impedance, the configuration impedance is a first configuration impedance, and the system contains a second tunable receiver,the second adjustable receiver having a second receiver antenna adapted to receive the primary wave and transmit a second secondary wave and a second receiver controller connected to the second receiver antenna, the second receiver controller being adapted to control the transmission of the second secondary wave by the second receiver antenna and to detect the primary wave received by the second receiver antenna, the second adjustable receiver having a modifiable impedance thus influencing the second secondary wave transmitted by the second receiver antenna, the second adjustable receiver initially being in the detection mode where the second adjustable receiver has a second basic impedance, the method further comprising a step of reconfiguring the second receiver in which when the global antenna receives the second secondary wave transmitted by the second adjustable receiver and the controller detects the second adjustable receiver,the global controller controls the second adjustable receiver to enter a cooperative mode in which the impedance of the second adjustable receiver alternates between a first configuration impedance of the second receiver and a second configuration impedance of the second receiver in order to detect other receivers,the reconfiguration step of the second adjustable receiver being of a duration of an order of magnitude greater than the duration of each alternation of the first and second configuration impedances of the second receiver. the first configuration impedance of the second receiver is the second base impedance of the second receiver. the first configuration impedance of the second receiver is far from the second configuration impedance of the second receiver. the first configuration impedance of the second receiver and the second configuration impedance of the second receiver are close to and on either side of the base impedance in the complex plane. the alternations of the configuration impedances of the second receiver in the cooperation mode are determined by an optimization algorithm,or by a predefined series of impedance values. the alternations of the configuration impedances of the second receiver in the cooperation mode are carried out at irregular non-periodic time instants. the global controller determines the alternations of the configuration impedances of the second receiver in the cooperation mode. the global controller controls the transition to cooperation mode of the identified receivers, and the controllers of these identified adjustable receivers determine the alternations of the configuration impedances when they are in cooperation mode. in the cooperation mode, the impedance of the adjustable receiver alternates between a plurality of configuration impedances. the adjustable receiver includes a plurality of adjustable components and associated antennas,and wherein: the global controller controls the emission by the global antenna of a global control wave containing identification information with an associated adjustment parameter to designate each adjustable component for which said adjustment parameter is intended, and said adjustable component controls the impedance of the associated antenna with respect to the adjustment parameter if the identification information is equal to its adjustable component identifier. the system further comprises an adjustable element connected to the global antenna, and in the receiver detection step the global controller further modifies the adjustable element impedance. the global controller simultaneously modifies the impedance of the adjustable element and the impedance of the identified adjustable receiver according to values determined by an optimization algorithm.

[0011] Also provided is a receiver detection system comprising: an adjustable receiver, a global antenna adapted to transmit a primary wave, and to receive a secondary wave transmitted by the adjustable receiver in response to the reception of the primary wave, a global controller connected to the global antenna, the global controller being adapted to control the transmission of the primary wave and to detect the adjustable receiver by means of the secondary wave received by the global antenna, characterized in that the adjustable receiver further comprises: a receiver antenna adapted to transmit the secondary wave; a receiver controller connected to the receiver antenna, the receiver controller being adapted to control the transmission of the secondary wave by the receiver antenna and to detect the primary wave received by the receiver antenna, the adjustable receiver having a modifiable impedance in order to modify the manner in which the primary wave is reflected and / or transmitted by the receiver antenna into a secondary wave, the system being configured such that when the adjustable receiver is detected by the global controller, the global controller controls the receiver controller to switch from a detection mode to a cooperation mode, in the detection mode, the adjustable receiver has a basic impedance, in the cooperation mode,the adjustable receiver impedance is alternated between a first configuration impedance and a second configuration impedance in order to detect other receivers, the cooperation mode being of a duration of an order of magnitude greater than a duration of each alternation of the first and second configuration impedances.

[0012] In various embodiments of the system, one and / or the other of the following provisions may optionally be used: The first configuration impedance is the base impedance. The first configuration impedance is distant from the second configuration impedance. The alternations of the configuration impedances in the cooperation mode are determined by an optimization algorithm, or by a predefined series of impedance values. the alternations of the configuration impedances in the cooperation mode are carried out at irregular non-periodic time instants. the global controller is adapted to control the alternations of the configuration impedances in the cooperation mode of the adjustable receiver. the global controller is adapted to control the transition to cooperation mode of the identified adjustable receivers, and the controller of the identified adjustable receiver is adapted to control the alternations of the configuration impedance when it is in cooperation mode.

[0013] Also provided is an adjustable receiver including: an antenna adapted to transmit a secondary wave in response to the reception of a primary wave and to receive an overall control wave; and a controller connected to the antenna, the controller being adapted to control the transmission of the secondary wave and to detect the received primary wave and the overall control wave, the adjustable receiver having a modifiable impedance thus influencing the emitted secondary wave, the adjustable receiver having a detection mode and a cooperation mode, the adjustable receiver switching from the detection mode to the cooperation mode depending on the overall control wave received, in the detection mode, the adjustable receiver has a base impedance, and in the cooperation mode, the impedance of the adjustable receiver is adapted to be alternated between a first configuration impedance and a second configuration impedance in order to detect other receivers, the cooperation mode being of a duration of an order of magnitude greater than a duration of each alternation of the first and second configuration impedances. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Other characteristics and advantages of the present disclosure will appear during the following description of one of its embodiments, given by way of non-limiting example, with reference to the attached drawings.

[0015] On the drawings: there figure 1 is a general diagram of an embodiment of a receiver detection system; the figure 2 illustrates an example of an adjustable receiver for the system of the figure 1 ; there figure 3 illustrates a temporal alternation of impedance for an adjustable receiver of the figure 2 ; and the figure 4 illustrates a dynamic list used by an algorithm that can be used by the system of the figure 1 .

[0016] In the various figures, the same numerical references designate identical or similar elements. DETAILED DESCRIPTION SYSTEM

[0017] There figure 1is a schematic perspective view of one embodiment of a system 10 receiver detection. In this example, the system 10 comprises a containing C having a volume V. The container C may be optional, and the volume V defined without physical walls. The container C is adapted to contain in its volume V one, two or a plurality of receivers. Among these receivers, one or more may be 30 adjustable receivers which once detected can be controlled to participate in the detection of other receptors, possibly contained in volume V. Adjustable receptors may include in particular a first adjustable receiver 30a and one second adjustable receiver 30b.The adjustable receivers 30 may be static or mobile. In itself, identification or simple communication also corresponds to detection. Thus, the system 10 is a system for detecting a receiver and / or identifying a receiver and / or communicating with a receiver. According to one example, the adjustable receiver(s) 30 is attached to merchandise (e.g., items for sale), and the container C is a bin of a store checkout. Thus, simply by placing the items in the bin, the checkout can identify the items without scanning them one by one. Other applications are described in the present disclosure.

[0018] As will be described below, the identified adjustable receivers participate as they are identified in the identification of other receivers present in the volume V. Although only two adjustable receivers 30a, 30b are illustrated in the figures, it is possible that the system 10 has three or more receivers similar to the adjustable receivers 30a, 30b. It is possible that among those identified, some are not receivers whose impedance can be adjusted.

[0019] In the particular case of the figure 1 , the container C is a parallelepiped comprising a bottom face C 1 , and four side faces C 2 , C 3 , C 4 , C 5 and one opening face C 6in opposition to the bottom face C 1 . Adjustable receivers 30 such as the first adjustable receiver 30a and the second adjustable receiver 30b can be introduced and / or extracted from the volume through the opening face C 6 . These adjustable receivers 30 can also be moved in the volume V. The first adjustable receiver 30a and the second adjustable receiver 30b are generally identical and will be described in detail below with reference to a generic receiver 30.

[0020] The system 10 further comprises: a global antenna 42 suitable for issuing a primary wave OP in volume V, and adapted to receive a secondary wave OS respectively emitted by each adjustable receiver 30 positioned in the volume V in response to the reception by this receiver of the primary wave OP, and a global controller 41connected to the global antenna 42, the global controller 41 being adapted to control the emission of the primary wave OP and to identify the adjustable receiver(s) 30 by the corresponding secondary wave OS emitted by the adjustable receiver(s) 30 and received by the global antenna 42. The global controller 41 and the global antenna 42 are shown in the figures according to one embodiment as being arranged outside the volume V. Alternatively, it could be that the global controller 41 and the global antenna 42 are arranged, both, or only one of the two, inside the volume V. ADJUSTABLE RECEIVER

[0021] One of the adjustable receivers 30 is schematically illustrated in figure 2 . The first adjustable receiver 30a and the second adjustable receiver 30b being similar to the generic adjustable receiver 30, the description of the structure and the mode of operation of the adjustable receiver 30 will be worth describing for the first adjustable receiver 30a and the second adjustable receiver 30b, knowing that the common elements will be annotated with the index “a” for the first adjustable receiver 30a and with the index “b” for the second adjustable receiver 30b.

[0022] The 30 adjustable receiver includes a antenna 32 adapted to transmit the secondary wave OS in response to the reception of the primary wave OP transmitted by the global antenna 42. The adjustable receiver 30 also comprises a controller 31 connected to antenna 32 and a adjustable component 35connected to the controller 31 on the one hand, and to the antenna 32 on the other hand. The controller 31 is configured to control the transmission of the secondary wave OS, and to detect the primary wave OP received and decode the information contained therein. The controller 31 further controls the impedance of the adjustable component 35, which influences the secondary wave OS transmitted by the antenna 32. The adjustable component 35 can be connected to the controller 31 in a wired or wireless manner. A local control wave OCl can be sent from the controller 31 to the adjustable component 35 to transmit the adjustment parameters to the adjustable component 35.

[0023] Each adjustable component 35 has an associated antenna. This antenna may be the antenna 32 of the adjustable receiver 30 or a separate antenna.

[0024] According to one embodiment, at least one of the adjustable receivers 30 comprises a plurality of adjustable components 35. The adjustable receiver 30 could comprise several adjustable components 35, each component having an associated antenna. In another embodiment, the adjustable receiver 30 comprises a single antenna for the plurality of adjustable components 35 of this receiver. The adjustable receiver 30 may comprise one or more controllers 31 to control everything. For simplification, the present description will describe, by way of example, adjustable receivers each having an antenna, a controller and an adjustable component, it being understood that there could be several antennas and / or several adjustable components and / or several controllers per adjustable receiver. GENERAL STRUCTURE

[0025] The adjustable receiver 30 is, for example, a device using so-called radio-identification technology or RFID for “radio frequency identification” in English.

[0026] The adjustable receiver 30 is for example a connected object, for example of the Internet of Things (IoT) type or of the WiFi or Bluetooth or LoRA network transmission type.

[0027] The adjustable receiver 30 could include one or more sensors (e.g. temperature, humidity, presence detection, gas detection, flow rate, voltage, current). One or more of the values measured by a sensor would be recorded in a receiver memory or any other memory and could be transmitted to the global controller 41 via the secondary wave OS.

[0028] The controller 31, the antenna 32 and the adjustable component 35 of the same receiver 30 can be grouped on a base 36so that the receiver 30 forms a compact object. According to one embodiment, the base 36 is for example a label for clothing or supplies, of low thickness, eg of thickness less than 0.2 mm, for example made of a flexible polymer material. The adjustable component 35, the antenna 32 and the controller 31 can for example be fixed on the base 36 by adhesion. The adjustable component 35, the antenna 32 and the controller 31 of the adjustable receiver 30 are themselves circuits of low thickness, so that the adjustable receiver 30 is a device of low thickness and flexible which is associated with an article. ADJUSTABLE COMPONENTS

[0029] There are several ways to get a 30 variable impedance adjustable receiver.

[0030] The adjustable component 35 of the adjustable receiver 30 is for example constituted by at least one adjustable electronic circuit connected to the antenna 32 in order to modify its electromagnetic radiation impedance, which characterizes its interaction with the electromagnetic field and in particular the waves around the receiver. The adjustable electronic circuit(s) is for example a capacitor, a diode, a transistor, or a combination thereof. This adjustable electronic circuit comprises an input controllable by the controller 31 in order to modify one of its electronic characteristics, that is to say more generally its electrical impedance which is the load impedance of the antenna 32 of the adjustable receiver 30. This modification involves the modification of the radiation impedance of the antenna 32 and the interaction with the waves.

[0031] The adjustable component 35 is therefore controllable by an input which can be modified for example by an electrical voltage value imposed by the controller 31, and which corresponds for example to one or more adjustment parameter values. These adjustment parameters can be determined by the global controller 41 or alternatively by the controller 31 of the adjustable receiver, as explained in more detail below.

[0032] The modification of the impedance of the adjustable receiver 30 modifies the spatial distribution of the primary wave OP in the volume V. This modification can be optimized so as to detect other receivers contained in the volume V, initially not identified by the global controller 41. In addition, as the receivers are detected in the volume V, they become controlled by the global controller 41 to participate in the modification of the spatial distribution of the primary wave OP to more effectively detect any other receivers present in the volume V. The modification of the impedance of the adjustable receiver 30 is much more complex than a focusing or a spatial directivity, it is a modification of the electromagnetic field in the volume around the receiver. MODES

[0033] When the impedance of the adjustable receiver 30 is modified, the way in which the primary wave OP is reflected and / or transmitted by the adjustable receiver 30 is also modified, which influences the overall electromagnetic field in the volume V. This modification is used here to detect other receivers invisible to the global controller 41. Thus, the global controller 41 can command the adjustable receiver 30 to switch to a cooperation mode wherein the adjustable receiver 30 has its impedance changing in order to modify the overall electromagnetic field in the volume V. This modification of the electromagnetic field can help to detect one or more other receivers hitherto silent with respect to the global controller 41.

[0034] Each adjustable receiver 30 contained in volume V is initially undetected by the global controller 41 and is in a detection mode. In the detection mode, the adjustable receiver 30 has a base impedance IB1.The base impedance IB1 is for example a load impedance of the antenna 32 of the adjustable receiver 30, that is to say an impedance adapted to receive a maximum of energy. For example the base impedance IB1 of an adjustable receiver 30 is 11 + 143*j (j is the complex for which j^2=-1). According to one embodiment, the base impedance IB1 of an adjustable receiver 30 is imposed by its controller 31 independently of the global controller 41. According to another embodiment, the base impedance IB1 of an adjustable receiver 30 is controlled by the global controller 41. In the detection mode, the adjustable receiver 30 could have several basic impedances, and the controller 31 of the adjustable receiver 30 could alternate between these different basic impedances. This alternation could be done without the global controller 41 controlling the controller 31 of the adjustable receiver 30, or alternatively under the control of the global controller 41.

[0035] When the global antenna 42 receives the secondary wave OSa emitted by a receiver located in the volume V and the receiver is an adjustable receiver 30, the global controller 41 can command the controller 31 of this adjustable receiver 30 to pass into the cooperation mode, to help identify other receptors contained within the volume.

[0036] In the cooperation mode the impedance of the adjustable receiver 30 is alternated between a first configuration impedance IC1 and one second configuration impedance IC2.For example, the first configuration impedance IC1 is IB1 - 20j, and the second configuration impedance IC2 is IB1 + 20j. The first configuration impedance IC1 could be infinite and the second configuration impedance IC2 could be zero or of low modulus or close to zero. It could be that the impedance of the adjustable element 35 is alternated between three or more configuration impedances. At least one of the first and second configuration impedances IC1, IC2 could be the base impedance IB in order to be suitable for harvesting energy.

[0037] According to one embodiment, the first configuration impedance IC1 is distant from the second configuration impedance IC2. By "distant" is meant that they have for example an order of magnitude of at least 10 between them. An impedance is a complex value, thus an impedance can be considered as distant from another impedance when for example: their moduli have values far from each other, such as for example a magnitude ratio of at least 2 between them, and preferably at least 10 (as mentioned above), or their phases have values far from each other, such as for example values of at least pi / 4 apart, and preferably greater than pi / 2, or the modulus of the difference of the first and second impedances has a significant value, for example greater than a threshold value, or for example greater than the modulus of the first impedance and / or greater than the modulus of the second impedance.

[0038] Many criteria for distances between impedances can be defined.

[0039] A small variation in the impedance of the adjustable components makes it possible to greatly modify the radiation impedance of the antenna which functions as a resonator: in particular at the base frequency of this resonator, the amplitude and phase of the impedance seen by the electromagnetic waves will vary greatly by this small change in load impedance. Thus, the antenna being dispersive, a small modification of its load impedance around its resonant frequency makes it possible to obtain a distant type alternation between a first impedance of configuration IC1 and a second impedance of configuration IC2. In addition, this type of resonator is quite easy to implement in an adjustable receiver 30 of small size and in particular of small thickness.

[0040] According to another embodiment, the first configuration impedance IC1 and the second configuration impedance IC2 are close to the base impedance IB. By "close" is meant that they have an order of magnitude of at most 10 between them. An impedance is a complex value, thus an impedance is close to another impedance when their moduli and / or their phases and / or the modulus of their complex difference are close to each other. An advantage of having the first configuration impedance IC1 and the second configuration impedance IC2 close to the base impedance IB is that the adjustable receiver 30 is adapted to harvest energy and remains powered during the cooperation mode. According to one embodiment, the first configuration impedance IC1 and the second configuration impedance IC2 are close and on either side of the base impedance in the complex plane.

[0041] The first configuration impedance IC1 and the second configuration impedance IC2 could both be greater than the base impedance IB1, or both less than the base impedance IB1, or one greater and one less than the base impedance IB1.

[0042] In the cooperation mode, there is therefore a fairly frequent alternation between the two or more configuration impedances, in the sense that the duration T1 of the cooperation mode is of an order of magnitude greater than the duration T2, T3 of each alternation of the first and second configuration impedances IC1 and IC2. The figure 3 illustrates this point for example. According to one example, the duration T1 of the cooperation mode is 100ms, and the duration T2, T3 of each alternation of the first and second configuration impedances IC1 and IC2 is 10ms. EXIT FROM COOPERATION MODE

[0043] Each adjustable receiver detected and switched to cooperative mode by the global controller 41 can remain in cooperative mode until all receivers present in volume V are detected.

[0044] The adjustable receiver(s) 30 may exit the cooperation mode after a predetermined period of time which could correspond to a time deemed sufficient to detect all the receivers present in the volume V, for example a few tens or a few hundreds of milliseconds. This period of time could be imposed by the global controller 41 or else be imposed by the controller 31 of the adjustable receiver 30. This time could be different for each or more of the receivers contained in the volume V. This time could be random.

[0045] According to another embodiment, the global controller 41 controls the output of the adjustable receivers of the cooperation mode. The global controller 41 can control this output to all the adjustable receivers detected simultaneously, or by group of receivers.

[0046] According to another embodiment, the adjustable receiver 30 remains in cooperation mode until the energy stored in this adjustable receiver is below a minimum value. ALTERNATION BASED ON PREDEFINED OR RANDOM SEQUENCES

[0047] According to one embodiment, the global controller 41 periodically defines adjustment parameters for the adjustable components 35 of the receivers 30 that it has detected randomly or in a predefined manner to scan a set of combinations of the adjustment parameters, which makes it possible to scan the volume V of the container with varied electromagnetic fields. At each impedance alternation, the global controller 41 concomitantly emits a primary wave OP to detect receivers with this new setting. The global controller 41 could alternatively emit the primary wave OP temporally after sending the impedance adjustment parameters.According to a variant of this embodiment, the global controller 41 only controls the transition of the identified receivers from the detection mode to the cooperation mode, and the controller of each identified adjustable receiver 30 periodically defines adjustment parameters for its adjustable components 35 in a random manner to scan a set of combinations of the adjustment parameters.

[0048] According to another embodiment, the timing of the alternations is not periodic, but irregular, dictated or random.

[0049] According to another embodiment, once an adjustable receiver 30 is detected and is in cooperation mode, its controller 31 is passive and the global controller 41 controls the alternations of the impedances of the adjustable receivers 30 via the controller 31 of the adjustable receiver.

[0050] According to one embodiment, the global controller 41 only controls the transition to cooperation mode of the identified receiver(s), and the controller(s) 31 of this or these receiver(s) control the alternations of the impedances of the adjustable receivers 30. These alternations can be preprogrammed. To this end, each controller 31 of the adjustable receiver 30 can include a memory 33 which would contain a programming of sequences of cooperation impedances to be alternated (with possibly a time delay associated with the sequence or with each alternation, for example alternation after an alternation duration of the order of a few milliseconds to a few hundred milliseconds) when the adjustable receiver 30 is switched to cooperation mode by the global controller 41. ALTERNANCE BASED ON OPTIMIZATION

[0051] According to another embodiment, the modification of the electromagnetic field by the adjustable receiver(s) 30 which have switched to cooperation mode can be done so as to optimize this electromagnetic field to detect other receivers. The optimization makes it possible to use several adjustable receivers 30 (those detected) to improve the electromagnetic field in the volume V and thus detect other receivers which could not have been detected before. The global controller 41 monitors the secondary waves OS received by the global antenna 42 (when these are received) coming from the different adjustable receivers 30 detected. Through these waves, the global controller 41 can for example determine reception information concerning the reception of the secondary wave OS received by its global antenna 42, this reception information being for example the reception level and / or the reception quality.

[0052] The global controller 41 can then use the reception information to estimate a value to be optimized (optimization value), this value being one of the information or a combination of this reception information.

[0053] The global controller 41 executes for example an optimization algorithm based on the previous parameter set (temporally), the previous estimated values and the current estimated value.

[0054] The optimization algorithm may be a maximization or a minimization of the estimated value, depending on the quantity represented by this value. In one or more successive steps, the optimization algorithm makes it possible to obtain an optimal set of parameters for detecting a new adjustable receiver 30. At each step or with predetermined periodicities, the global controller 41 applies the new set of parameters to the adjustable receivers 30 that it has identified and / or determines reception information to carry out the following iteration. These iterations may be carried out at a very high rate so that the duration of this optimization is very short compared to the number of receivers to be detected and / or identified in the volume.

[0055] The optimal set of parameters makes it possible, for example, to improve the reception level of the secondary wave OS on the global antenna 42. Thanks to this modification by the optimized state of the adjustable components of the identified receivers, such as for example the first receiver 30, the propagation field of the secondary wave OS is improved towards the global antenna 42, and the detection and / or identification of the receiver, such as for example that of a second receiver 30b hitherto unidentified in the volume V is improved or even becomes possible.

[0056] Thus, according to one embodiment, the global controller 41 determines the set of parameters for adjusting the plurality of adjustable components of the receivers identified by the global controller 41, for example to optimize the reception of the secondary wave by the global antenna 42. The optimization relates to the estimated value which is, for example, an estimation of the reception level and / or the reception quality of the secondary wave by the global antenna 42. DYNAMIC OPTIMIZATION

[0057] The optimization is dynamic, that is to say that the number of parameters sent by the global controller 41 to the adjustable receivers 30 to adjust the adjustable components 35 increases as new receivers are detected in the volume V. Thus, when a first adjustable receiver 30a is detected, the global controller 41 will command the change in the impedance of this adjustable receiver, and will do the same thereafter for each new adjustable receiver detected. Thus after a few iterations, for example five adjustable receivers 30 will be controlled by the global controller 41 to detect a new receiver present in the volume V.

[0058] To illustrate, let us take the example of the first receiver 30a and the second receiver 30b present in the volume V, assuming that they are initially unidentified by the global controller 41. The first 30a and the second 30b receivers are initially (t=t0) in the detection mode with respectively, a basic impedance IBa, IBb fixed only by their associated controller 31a, 31b (independently of the global controller 41). In a first step, receiver detection step, the first receiver 30a is detected by the global controller 41 when the global antenna 42 receives the secondary wave OSa emitted by the first receiver 30a (time t=t1). The global controller 41 can then add the first receiver 30a to a dynamic list L of identified receptors (see figure 4 ). The dynamic list L can be saved in a memory of the global controller 41. The list is dynamic because it is updated in real time by adding the receivers detected by the global controller 41 as they are detected and switch to cooperation mode.

[0059] In a third stage, stage detection of the second receiver, the global antenna 42 receives the secondary wave OSb emitted by the second receiver 30b. The global controller 41 identifies the second receiver 30b and can then add the second receiver 30b to its dynamic list L of identified receivers (time t=t2). The global controller 41 further commands the controller 31b of the second receiver 30b to switch to cooperation mode wherein the impedance of the second adjustable receiver 30b alternates at least between a first impedance of configuration IC1b and a second impedance of configuration IC2b.

[0060] According to one embodiment, the first configuration impedance IC1b of the second receiver 30b is distant from the second configuration impedance IC2b of the second receiver 30b. By "distant" is meant that they have for example an order of magnitude of at least 10 between them. An impedance is a complex value, thus an impedance can be as distant from another impedance when for example: their moduli have values far from each other, such as for example a magnitude ratio of at least 2 between them, and preferably at least 10 (as mentioned above), or their phases have values far from each other, such as for example values of at least pi / 4 apart, and preferably greater than pi / 2, or the modulus of the difference of the first and second impedances has a significant value, for example greater than a threshold value, or for example greater than the modulus of the first impedance and / or greater than the modulus of the second impedance.

[0061] Many criteria for distances between impedances can be defined. OPTIMIZATION WITH PRE-RECORDED SETTINGS

[0062] According to one embodiment, the global controller 41 periodically defines adjustment parameters for the adjustable components of the detected receivers according to a pre-recorded table to scan a set of combinations of the adjustment parameters.

[0063] This pre-recorded table is for example defined by knowledge of the propagation of the primary OP waves in the volume V either by simulation or by measurement of the middle of the volume V. The pre-recorded table is for example defined to ensure that the entire volume V can be scanned with a predetermined spatial precision.

[0064] Then, the global controller 41 proceeds as previously: at each adjustment of the adjustable components of the identified receivers, the global controller 41 also commands the emission of a primary wave OP to detect receivers with this new adjustment. This procedure allows it to detect one or more new receivers (adjustable or not) in the volume V. After a predefined number of combinations, this procedure makes it possible to know all the receivers of the volume V.

[0065] According to a variant, the global controller 41 periodically performs, for example during a predetermined time range (a time range and / or a day determined during a week and / or during a month), a calibration of said pre-recorded table by searching for the optimum adjustment parameters for adjustable reference receivers 30.

[0066] This further optimization may be based on the secondary wave OS received by the global controller 41. The global controller 41 determines reception information regarding the reception of the return secondary wave OS by its antenna (reception level and / or reception quality). The global controller 41 then performs an optimization of all the adjustment parameters for identified adjustable receivers 30.

[0067] Following these optimizations of the adjustment parameters for identified adjustable receivers, the global controller 41 deduces the pre-recorded table using various techniques, such as a parameterization model and / or an interpolation technique.

[0068] According to a variant of this embodiment, the global controller 41 only controls the transition of the identified adjustable receivers 30 from the detection mode to the cooperation mode, and the controller 31 of each receiver periodically defines adjustment parameters for the adjustable components according to a table pre-recorded in the memory of the receiver considered to scan a set of combinations of the adjustment parameters. RECEIVER - IDENTIFICATION

[0069] Furthermore, the memory 33 of each receiver 30 may comprise a adjustable receiver identifier IDrr, allowing the receivers to be differentiated from each other (the identifiers are all different).

[0070] In this case, the global controller 41 can emit in a global control wave emission OCg a IID credential with an impedance adjustment parameter, which makes it possible to designate the identified adjustable receiver of the system 10 for which said adjustment parameter is intended. Thus, the global controller 41 transmits, for example, the entire set of parameters (all the adjustment parameters) sequentially, each adjustment parameter being associated with identification information so that the adjustable receiver 30 receiving said adjustment parameter is the only one to apply said adjustment parameter in question.

[0071] In the case where the adjustable receiver 30 includes a plurality of adjustable components with their associated antennas, the global control wave contains identification information with an associated adjustment parameter to designate each adjustable component for which said adjustment parameter is intended, and the adjustable component drives the impedance of the associated antenna with respect to the adjustment parameter if the identification information is equal to its adjustable component identifier IDcr.

[0072] The receiver 30 can thus comprise a receiving device 34 of the global control wave OCg which decodes an adjustment parameter contained in this global control wave OCg, coming from the global controller 41. The controller 31 of the adjustable receiver 30 then uses the adjustment parameter to control and modify the impedance of the associated adjustable component 35.

[0073] The receiving device 34 of the receiver 30 then decodes in the global control wave OCg, the identification information IID and the adjustment parameter. Then, the adjustable receiver 30 controls its impedance (i.e. the adjustable component 35 controls the impedance of its associated antenna) according to the adjustment parameter if the identification information is equal to its adjustable receiver identifier IDrr.

[0074] The global controller 41 optionally periodically emits primary waves OP into the volume V of the container C to detect and identify receivers, and it periodically emits global control waves OCg into the volume V to adjust the adjustable receivers 30 that have been detected. Each adjustable receiver 30 detected then selects the adjustment parameter intended for it.

[0075] According to a variant, the memory 33 of the adjustable receiver(s) 30 stores a set of adjustment parameters (pre-recorded and / or recorded by transmission from the controller) and one (or more) reading periods associated with these adjustment parameters. This set of adjustment parameters and reading periods are known to the global controller 41. This arrangement can allow the global controller 41 to avoid systematically sending new adjustment parameters to the adjustable receivers; i.e. which limits the need for transmission. Optionally, this set of adjustment parameters and / or these reading periods are different for each adjustable receiver 30.

[0076] According to a first variant of the global controller 41, the global controller 41 includes in its memory 43 the dynamic list L of the identifiers of the adjustable components or of the adjustable receiver if it has only one adjustable component, this list being filled with the adjustable receiver identifiers IDrr of the system 10 identified to be able to transmit the identifier of the adjustable component with the adjustment parameter. Each adjustable receiver 30 possibly transmits periodically by a return wave, which can be the secondary wave Osa, its adjustable receiver identifier IDrr. The global controller 41 then establishes the list of adjustable receivers 30 identified in the system 10 and updates it each time a new receiver identifier is received.Furthermore, an adjustable receiver 30 may be removed from the dynamic list or may be deactivated in said list (by an activity flag) if the global controller 41 no longer receives the identifier of the adjustable receiver 30 for a period greater than a limit duration of inactivation of an adjustable receiver 30.

[0077] Thus, by this dynamic operation, the global controller 41 will always use efficient or functional adjustable receivers 30. This dynamic operation also facilitates the installation of the system 10 which automatically adapts to the adjustable receivers 30 present in the volume V.

[0078] Furthermore, according to a variant, the adjustable receiver 30 will periodically emit its adjustable identifier IDrr only in the presence of a primary wave OP and / or a global control wave OCg coming from the antenna 42 of the controller 41, in particular: either because this adjustable receiver 30 uses a energy recovery device 37of this wave for its operation. In the absence of power, the adjustable receiver 30 will be automatically switched off and will not broadcast its identifier; either because this adjustable receiver 30 is designed not to transmit its identifier if it does not receive a primary wave OP or a global control wave OCg for a period greater than a predetermined standby duration. RECEIVER - ALTERNATING IMPEDANCE CONTROL

[0079] The alternations of the impedances in the cooperation mode of the identified adjustable receivers 30 can be carried out in different ways. According to one embodiment, an optimization algorithm determines the impedances of each of the adjustable components of the dynamic list L in an iterative manner with the aim of optimizing the electromagnetic field in the volume V.

[0080] According to a variant, the global controller 41 comprises a memory which records one or more sets of optimal parameters for detecting receptors present in the volume V and which would still be unidentified. In this way, the optimization algorithm can start its process from one or more of the recorded sets of parameters, which makes it possible to save time on optimization and to avoid transient effects.

[0081] According to a variant, the optimization algorithm monitors its performance and stops its optimization iterations when a stopping criterion is reached. The stopping criterion may be the reception by the global controller 41 of an identifier of a receiver not yet identified. In this way, insignificant variations or fluctuations in the reception of the secondary wave OS can be avoided.

[0082] Finally, the previous embodiments of the global controller 41 can be combined to carry out part of the adjustment parameters by optimization on the received secondary wave OS, part of the adjustment parameters by random adjustment, and part of the adjustment parameters by predefinition in the volume V. This strategy makes it possible to identify even more receivers in the volume V, and more quickly.

[0083] Furthermore, so that a receiver can receive and decode an adjustment parameter intended for it, the global controller 41 determines this adjustment parameter for example according to the optimization procedure described above for each adjustable receiver 30 included in the system 10 (i.e. the receivers detected and listed by the global controller 41 in the dynamic list L at this time), and the global controller 41 transmits each adjustment parameter to the corresponding associated receiver in the emission of a global control wave OCg different from the primary wave OP.

[0084] In particular, this transmission in a control wave OC is carried out by any type of coding and / or any type of modulation in the transmission signal of the global control wave OCg that the global controller 41 provides to the global antenna 42.

[0085] Alternatively, the global controller 41 may command all adjustable receivers 30 at the same time to change their impedance or adjust their impedance, depending on a parameter that is specific to each receiver. For example, a command may be issued that depends on the identity of each receiver (“this one includes a 0 or not”, “this one has its last even number”, etc.), and that modifies the impedance of each reception according to a defined formula. RECEIVER - ENERGY RECOVERY

[0086] Furthermore, with reference to the Figure 2 , one (or more) adjustable receivers 30 may further include a energy storage organ 38adapted to store and possibly accumulate energy received by the energy recovery device 37. In this way, the adjustable receiver 30 will have more autonomy and it is capable of operating for a duration determined by the capacity of said energy storage member. This energy storage member is for example an electrical capacity, or a battery, or any other energy storage device.

[0087] The energy recovery device 37 is for example capable of recovering energy from the primary wave OP and / or from the global control wave OCg to power its reception device 34 and / or its controller 31 and / or the adjustable component(s) 35.

[0088] The adjustable receiver 30 can thus be energy autonomous and also autonomous for the adaptation of its impedance. The adjustable component(s) 35 of each adjustable receiver 30 could not need a wired connection with the controller 31 of the adjustable receiver 30, and also have their energy recovery device.

[0089] Advantageously, all the adjustable receivers of the system 10 can each have (individually) their own energy recovery device 37 and are thus independent of each other. ADJUSTABLE ELEMENTS

[0090] Optionally, and referring again to the figure 1 , system 10 can further include one (or more) adjustable element 20fixed in the volume V. The adjustable elements 20 may have an impedance which can be modified to modify the manner in which the primary wave OP is reflected and / or transmitted by each adjustable element 20, in the same manner as previously discussed for the adjustable receivers 30.

[0091] The adjustable elements 20 are structurally and operationally similar to the adjustable receivers 30, except that they are fixed relative to the volume V, are identified at all times by the global controller 41, and are controlled at all times directly by the global controller 41. Thus, they are passive elements which have their impedance dictated by the global controller 41.

[0092] The adjustable elements 20 are preferably in a number N greater than or equal to two. Optionally, the number N is greater than five, or ten or twenty to further modify the distribution of the primary wave OP in the volume V.

[0093] According to one embodiment, the global control wave OCg or the primary wave OP emitted by the global controller 41 makes it possible to control or pilot the adjustable elements 20. Thus, the global controller 41 can simultaneously control or pilot the adjustable elements 20 and adjustable receivers 30 of the system 10.

[0094] Further, each adjustable element 20 includes a receiving device of the global control wave OCg which decodes an adjustment parameter contained in this global control wave OCg, coming from the global controller 41. The adjustable element 20 then uses the adjustment parameter to control and modify its impedance.

[0095] The global control wave OCg may be in the same or different frequency band as the primary wave OP. Advantageously, these waves are at a different frequency, and the transmissions are independent.

[0096] Furthermore, since the adjustable elements 20 are fixed to the container C in a plurality of different positions, the distribution of the primary wave OP in the volume V can be further modified. The positions of the adjustable elements 20 on the container C can be optimized to best cover the volume V with a minimum number of adjustable elements 20. This spatial optimization can be carried out by simulation and / or measurement of the volume V. A margin can be added to the number of adjustable elements 20 used to increase the identification robustness of the system 10. ADJUSTABLE ELEMENTS - OPTIMIZATION

[0097] The adjustable element(s) 20 can be taken into account in the adjustment and / or optimization processes described above for the adjustable receivers 30. The adjustable element(s) 20 being identified at all times, they can also then be part of the dynamic list L. ADJUSTABLE ELEMENTS - ENERGY RECOVERY

[0098] Furthermore, one, more or all of the adjustable elements 20 (if these are part of the system 10) may comprise an energy recovery device similar to that described for the adjustable receivers 30 above. The adjustable element 20 can thus be autonomous in energy and also autonomous for the adaptation of its impedance. In this case, each adjustable element 20 will not need a wired connection with a general control module, and it will not need a wired connection with the global controller 41 of this detection system 10. ADJUSTABLE ELEMENTS - SPATIAL DISTRIBUTION

[0099] The adjustable elements 20, when present in the system 10, can be located in the volume V without having any wiring constraints (for example inside or outside this container C or on any surface of the container C). This gives great freedom to place the adjustable elements 20 at best to maximize the possibilities of detection and identification of all the adjustable receivers 30 in the volume V. This also makes it possible to equip a container C very quickly since it is sufficient only to fix the adjustable elements 20 on the container C and to position the global antenna 42 near the volume V.

[0100] The adjustable elements 20 may be fixed to the container C by any fixing means. For example, the adjustable elements 20 are fixed to the container C by an adhesive or by an elastic fixing clip or by a screw or by a rivet or by interlocking or by fitting.

[0101] Furthermore, the adjustable elements 20 advantageously have a planar shape. A portion of their electrical circuit is for example directly printed on a support. The support is for example made of paper or cardboard or plastic or fabric, and for example with a face comprising an adhesive. Optionally, the portion of the electrical circuit comprises an antenna. The adjustable elements 20 may also have flexibility which allows them to be bent according to a radius of curvature which allows them to be fixed on non-planar surfaces. Thanks to these arrangements, the adjustable elements 20 can be easily fixed on a large number of surfaces (planar or non-planar) of a container, which allows them to be positioned at locations suitable for controlling the electromagnetic field inside the volume V. NON-ADJUSTABLE ELEMENTS

[0102] The system 10 according to the invention may further comprise non-adjustable elements 29fixed in the volume V having a predetermined and fixed impedance, this impedance being adapted to modify the manner in which the primary wave OP is reflected and / or absorbed by said non-adjustable element 29.

[0103] This or these non-adjustable elements 29 are fixed to the container C at different positions. These non-adjustable elements 29 make it possible to modify in a non-controllable manner the distribution of the primary wave OP distributed in the volume V.

[0104] For example, these non-adjustable elements 29 are resonant elements in the frequency band of the primary wave OP.

[0105] For example, a non-adjustable element 29 can carry out a reflection of the primary wave OP and / or an absorption of the primary wave OP. This non-adjustable element can make it possible to confine the primary wave OP in the volume V of the container C to optimize the efficiency in the volume V of the adjustable elements 20 and the adjustable receivers 30.

[0106] The positions of the non-adjustable elements 29 on the container C can be optimized so that the primary wave best covers the volume V with a minimum number of adjustable elements 20. This optimization can be carried out by simulation and / or by measurement (experimental method) of the volume V. INDUSTRIAL APPLICATION

[0107] The system 10 incorporating adjustable receivers which participate in the detection of other receivers by their participation in increasing numbers in the modification and / or optimization of the electromagnetic field as they are identified by the global controller 41 allows the global controller 41 to determine more quickly other receivers present in the volume V and not yet identified.

[0108] This system 10 has many industrial applications.

[0109] For example in: furniture (optionally equipped with adjustable elements 20), such as storage furniture and adapted to receive products, such as a cabinet, a shelving unit, each product having an adjustable receiver attached thereto, or such as office furniture such as a desk, a table; or a cash register container of a store (optionally equipped with adjustable elements 20), in which products are inserted, each product having an associated adjustable receiver 30. The system will be able to identify the products by the adjustable receivers attached to these products, and the cash register will be able to issue an invoice; or a shopping trolley of a store (optionally equipped with adjustable elements 20) and containing within it several articles for purchase, each article having an associated adjustable receiver 30;or a bag (optionally equipped with adjustable elements 20), for example a shopping bag, and containing inside several articles each having an adjustable receiver 30; or a motor vehicle or an airplane or a train (optionally equipped with adjustable elements 20 and / or adjustable receivers 30) and carrying inside material each having an adjustable receiver 30; or a premises (optionally equipped with adjustable elements 20), for example an industrial premises such as a warehouse, or a residential premises, or a premises of a shopping center, having movable elements each with an associated adjustable receiver 30; or a store shelf, where each product is equipped with an adjustable receiver 30; or a storage or transit center for products, which can be sold by mail order, and where each product is equipped with an adjustable receiver 30.;

Claims

1. Method for detecting receivers, implemented by a detection system (10) comprising a general antenna (42) suitable for emitting a primary wave (OP), and a general controller (41) connected to the general antenna, the system comprising an adjustable receiver (30) having a receiver antenna (32) suitable for receiving the primary wave and for emitting a secondary wave (OS), the adjustable receiver having a receiver controller (31) connected to the receiver antenna, the receiver controller being suitable for detecting the primary wave received by the receiver antenna and for commanding the emission of the secondary wave by the receiver antenna, the adjustable receiver having an adjustable component (35) connected to the controller (31)and to the antenna (32), the adjustable component (35) and the adjustable receiver, having an impedance modifiable by the controller so as to influence the secondary wave emitted, the adjustable receiver initially being in a detection mode where the adjustable receiver has a base impedance (IB), the method comprising: - a receiver detection step in which the adjustable receiver is detected by the general controller when the general antenna receives the secondary wave emitted by the adjustable receiver, followed by - a reconfiguration step in which the general controller commands the receiver controller to switch to an interaction mode where the impedance of the adjustable receiver is alternated between a first configuration impedance (IC1) and a second configuration impedance (IC2) in order to detect other receivers, the reconfiguration step being of a duration (T1) that is an order of magnitude higher than the duration (T2, T3) of each alternation of the first and second configuration impedances.

2. Method according to claim 1, wherein the base impedance is imposed by the receiver controller independently of the general controller.

3. Method according to claim 1 or 2, wherein the first configuration impedance is the base impedance.

4. Method according to one of claims 1 to 3, wherein the first configuration impedance is at a distance from the second configuration impedance.

5. Method according to one of claims 1 to 3, wherein the first configuration impedance and the second configuration impedance are close to and with one on either side of the base impedance within the complex plane.

6. Method according to one of the preceding claims, wherein the adjustable receiver is a first adjustable receiver (30a), the receiver antenna (32) is a first receiver antenna, the primary wave is a first primary wave, the secondary wave is a first secondary wave, the receiver controller (31) is a first receiver controller, the adjustable component (35) being a component adjustable by the first receiver, the base impedance is a first base impedance, the configuration impedance is a first configuration impedance, and the system contains a second adjustable receiver (30b), the second adjustable receiver having a second receiver antenna (32b) suitable for receiving the primary wave and emitting a second secondary wave (OSb), a second receiver controller (31b) connected to the second receiver antenna, and an adjustable component of the second receiver connected to the second receiver controller and to the second receiver antenna, the second receiver (30) controller (31b) being suitable for controlling the emission of the second secondary wave by the second receiver antenna and for detecting the primary wave received by the second receiver antenna, the adjustable component of the second adjustable receiver having an impedance modifiable by the second receiver controller so as to influence the second secondary wave emitted by the second receiver antenna, the second adjustable receiver initially being in detection mode where the second adjustable receiver has a second base impedance, the method further comprising a reconfiguration step of reconfiguring the second receiver in which, when the general antenna receives the second secondary wave emitted by the second adjustable receiver and the controller detects the second adjustable receiver, the general controller commands the second adjustable receiver to switch to interaction mode where the impedance of the second adjustable receiver alternates between a first configuration impedance (IC2a) of the second receiver and a second configuration impedance (IC2b) of the second receiver in order to detect other receivers, the reconfiguration step of reconfiguring the second adjustable receiver being of a duration (T1b) that is an order of magnitude higher than the duration (T2b, T3b) of each alternation of the first and second configuration impedances of the second receiver.

7. Method according to claim 6, wherein the first configuration impedance of the second receiver is the second base impedance of the second receiver.

8. Method according to claim 6 or 7, wherein the first configuration impedance of the second receiver is at a distance from the second configuration impedance of the second receiver.

9. Method according to one of claims 6 or 7, wherein the first configuration impedance of the second receiver and the second configuration impedance of the second receiver are close to and with one on either side of the base impedance within the complex plane.

10. Method according to any one of the preceding claims, wherein the alternations of the configuration impedances of the second receiver in interaction mode are determined by an optimization algorithm, or by a predefined series of impedance values.

11. Method according to any one of the preceding claims, wherein the alternations of the configuration impedances of the second receiver in interaction mode are carried out at irregular non-periodic time instants.

12. Method according to any one of the preceding claims, wherein the general controller determines the alternations of the configuration impedances of the second receiver in interaction mode.

13. Method according to any one of the preceding claims, wherein the general controller commands the switch to interaction mode of the identified receivers, and the controllers of these identified adjustable receivers determine the alternations of the configuration impedances when they are in interaction mode.

14. Method according to any one of the preceding claims, wherein, in interaction mode, the impedance of the adjustable receiver alternates between a plurality of configuration impedances.

15. Method according to any one of the preceding claims, wherein the adjustable receiver includes a plurality of adjustable components and associated antennas, and wherein: - the general controller commands the emission by the general antenna of a general control wave containing identification information along with an associated adjustment parameter to designate each adjustable component for which said adjustment parameter is intended, and - said adjustable component controls the impedance of the associated antenna in relation to the adjustment parameter if the identification information is equal to its adjustable component identifier (IDcr).

16. Method according to any one of the preceding claims, wherein the system further comprises an adjustable element (20) connected to the general antenna, and in the receiver detection step the general controller also modifies the impedance of the adjustable element.

17. Method according to claim 16, wherein the general controller simultaneously modifies the impedance of the adjustable element and the impedance of the identified adjustable receiver, according to values determined by an optimization algorithm.

18. Receiver detection system (10) comprising: - an adjustable receiver (30), - a general antenna (42) suitable for emitting a primary wave (OP), and for receiving a secondary wave (OS) emitted by the adjustable receiver in response to reception of the primary wave, - a general controller (41) connected to the general antenna, the general controller being suitable for commanding the emission of the primary wave and for detecting the adjustable receiver by means of the secondary wave received by the general antenna, the adjustable receiver further comprising: - a receiver antenna (32) suitable for emitting the secondary wave; - a receiver controller (31) connected to the receiver antenna, the receiver controller being suitable for commanding the emission of the secondary wave by the receiver antenna and for detecting the primary wave received by the receiver antenna, - an adjustable component (35) connected to the controller (31) and to the antenna (32), the adjustable component, and thus the adjustable receiver, having an impedance modifiable by the controller in order to modify the manner in which the primary wave is reflected and / or transmitted by the receiver antenna as a secondary wave, characterized in that the system being configured such that, when the adjustable receiver is detected by the general controller, the general controller commands the receiver controller to switch from a detection mode to an interaction mode, - in detection mode, the adjustable receiver has a base impedance (IB), - in interaction mode, the impedance of the adjustable receiver is alternated between a first configuration impedance (IC1) and a second configuration impedance (IC2) in order to detect other receivers, the interaction mode being of a duration (T1) that is an order of magnitude higher than the duration (T2, T3) of each alternation of the first and second configuration impedances.

19. System according to claim 18, wherein the first configuration impedance is the base impedance.

20. System according to claim 18 or 19, wherein the first configuration impedance is at a distance from the second configuration impedance.

21. System according to any one of claims 18 to 20, wherein the alternations of the configuration impedances in interaction mode are determined by an optimization algorithm or by a predefined series of impedance values.

22. System according to any one of claims 18 to 21, wherein the alternations of the configuration impedances in interaction mode are carried out at irregular non-periodic time instants.

23. System according to any one of claims 18 to 22, wherein the general controller is suitable for commanding the alternations of the configuration impedances in interaction mode of the adjustable receiver.

24. System according to any one of claims 18 to 23, wherein the general controller is suitable for commanding the switch to interaction mode of the identified adjustable receivers, and the controller of the identified adjustable receiver is suitable for commanding the alternations of the configuration impedance when it is in interaction mode.

25. Adjustable receiver (30) comprising: - an antenna (32) suitable for emitting a secondary wave (OS) in response to receiving a primary wave (OP) and for receiving a general control wave different from the primary wave; and - a controller (31) connected to the antenna, the controller being suitable for commanding the emission of the secondary wave and for detecting the primary wave received and the general control wave, - an adjustable component (35) connected to the controller (31) and to the antenna (32), the adjustable component having a impedance modifiable by the controller so as to influence the secondary wave emitted, the adjustable component, and thus adjustable receiver having a detection mode and an interaction mode, the adjustable receiver being adapted to switch from detection mode to interaction mode according to the general control wave received, - in detection mode, the adjustable receiver has a base impedance (IB), and - in interaction mode, the impedance of the adjustable receiver is adapted to alternate between a first configuration impedance (IC1) and a second configuration impedance (IC2) in order to detect other receivers, the interaction mode being of a duration (T1) that is an order of magnitude higher than the duration (T2, T3) of each alternation of the first and second configuration impedances.