AU725321B2

AU725321B2 - System for communication by remote interrogation enabling the transmission of inhibition commands

Info

Publication number: AU725321B2
Application number: AU57677/98A
Authority: AU
Inventors: Richard Kalinowski; Michel Leduc
Original assignee: Gemplus SCA; Gemplus Card International SA
Current assignee: Gemplus SA
Priority date: 1996-12-27
Filing date: 1997-12-24
Publication date: 2000-10-12
Anticipated expiration: 2017-12-24
Also published as: DE69715251D1; EP0954824A1; FR2758027B1; WO1998029826A1; JP4078462B2; EP0954824B1; ES2183235T3; DE69715251T2; FR2758027A1; JP2002511985A; AU5767798A; CA2275956A1

Description

SYSTEM FOR COMMUNICATION BY REMOTE INTERROGATION ENABLING THE TRANSMISSION OF INHIBITION COMMANDS The invention presented here relates to a system for communication between a component of an emission/reception interrogator and several electronic responder labels which contain information. The invention applies not only to any system for radiofrequency (RF) communication but also to any system for infra red (IR) communication. In these systems, the interrogation component emits signals according to an established protocol towards the label(s) in order to interrogate it (them).

These systems can, in particular, be used for the recognition of individual badge carriers, vehicles carrying badges for tolls on a roadway or even goods stored or put up for sale in stores.

Electronic labels, called badges for some applications, are more generally called "transponders" (transmitter-responder) because their main role is to transmit information especially in response to commands of the interrogation system. As a result, in the following description, transponders will be used to designate these electronic labels or badges.

The communication parameters of a transponder are generally fixed and the behavior of the integrated circuit that it contains is, as a consequence, fixed for the rest of its life cycle.

However, this fixed behavior is a disadvantage since no adaptation to the conditions of the transponder environment is possible. It is, though, often advantageous to be able to change certain parameters, such as the speed of transmission or the duration of the sequence of emission of the integrated circuit, for example, as a function of the level of perturbation of the electromagnetic field in which the transponder is located or as a function of the interference which is likely to appear cyclically.

Moreover, in many applications, such as the storage or the sale of merchandise or even the sending of parcel post for example, it is necessary to follow the progress of the labeled product. The progress of a product can, in particular, be regularly followed during service contracts, for example.

However, in some cases it can prove to be necessary to induce a temporary inhibition of the integrated circuit of a transponder in order to prevent use or re-use of a labeled product when this is not authorized by the dealer.

.In the same way, when a labeled product is purchased, for example, it can be advantageous to cause a temporary inhibition of the integrated circuit so as to not set off the alarm of a detector placed at the exit of a store.

Such a temporary inhibition makes possible a later reactivation of the integrated circuit so as to be able to perform operations such as the service of the product, for example.

In this case, the interrogation component can read in the memory of the integrated circuit in order to know the purchase date or the date of the end of the product guarantee, for example. If necessary, it will also be possible to write information in the memory of the integrated circuit if the circuit allows it, about the different operations which have been done on the product.

Moreover, in the context of anti-fraud operations, it will be preferable to induce a permanent inhibition of the integrated circuit of the transponder so as to avoid any untimely reuse of the labeled product.

There also exists, currently, systems for communication which enable inhibitions.

Thus, the patent application PCT WO 92/22040 describes an transponder identification system for which, during the interrogation of a transponder, the other transponders inhibit each other for a moment.

For this, the transponders each have a control and sequence circuit and inhibition mechanisms. Data received by each transponder is decoded and sent to the control and sequence circuit which manages and controls it the circuit decides in particular on the response to send, and on passage into an inhibited mode of the transponder. When it decides the passage into an inhibited mode of the transponder, it sends a command signal to the inhibition mechanisms.

These control circuits designed to induce the inhibition of the integrated circuits are, however, costly and can not, as a consequence, be integrated into transponders which are considered economical, i.e. coming out at low cost.

It was thus necessary to find a mechanism which allows the command of the inhibition of the integrated circuits of the economical transponders by the interrogation component.

Moreover, another problem which arose lies in the fact that quite often the economical transponders are made from passive electronic devices which obtain the power supply from the radiofrequency or infra-red signal generated by the interrogation component These devices are created by a read-only integrated circuit, linked by two contacts to an antenna.

As a result, it was necessary to find a mechanism to command the inhibition of the integrated circuits, by the interrogation component, without the possibility in this case, of writing in a memory zone of this integrated circuit The invention presented here proposes a solution consisting of implementing a Ssimple technique and a cost-effective technology in order to induce a controlled inhibition ofthe integrated circuit of a transponder by the interrogation component where the inhibition mode corresponds to an application stored in memory in the message that the transponder sends to the interrogation component during its initialization.

o 2a According to the present invention there is provided a system of communication between a component of an emission/reception interrogator, fitted to emit an energy field, and at least one transponder including an integrated circuit having a memory, wherein in response to initialisation, the transponder sends a carrier message (ATR), in particular, of information (MOD) characterized by its inhibition mode, and information (RR) which defines the duration of stand-by periods (PV) between two messages, during which the interrogation component is ready to send one or more inhibition command(s) based on a registered mode (MOD).

Based on another characteristic of the invention, after the message (ATR) is sent, the transponder sends information (CMID, TMID, APID, TID, CRC) which allows it to be identified.

o* So..* oo o 9 o* 99 o•* W:\marie\GABNODEL\57677-98.doc According to another characteristic of the invention, the integrated circuit opens at least one reception window FE, inside the stand-by periods PV, during which it is ready to receive the. command signals of inhibition sent by the interrogation component.

According to another characteristic of the invention, the instant of the opening of the reception window(s) (FE) is registered in a memory of the interrogation component as a function of the type of transponder (TID) and the information (RR) which defines the duration of the stand-by periods (PV).

According to another characteristic of the invention, the instant of the opening of the reception windows FE are activated successively or non-successively within one or more stand-by periods PV.

According to another characteristic of the invention, the stand-by periods PV of the integrated circuit have a fixed or variable duration.

When the duration of these stand-by periods PV is fixed, it corresponds preferably to that of one byte, and the instant of the opening of each reception window FE is defined by the posit i o n of one predetermined bit of the byte which defines the corresponding stand-by period PV.

On the other hand, when the length of these stand-by periods PV is variable, it is between the duration of a bit and that of 16 bits and determined according to a pseudorandom sequence, and the instant of the opening of each reception window FE is defined by the position of a predetermined bit, from the corresponding stand-by period PV, according to a predetermined pseudo-random sequence.

According to another characteristic of the invention, an inhibition command consists in extending the energy field emitted by the interrogation component for a short period.

Preferably, the interrogation component sends a predetermined number of inhibition commands, in the form of disconnect pulses (PCI), within the reception windows FE.

The different inhibition modes of the integrated circuit of a transponder are: the total permanent inhibition, the partial permanent inhibition, temporary total inhibition and temporary partial inhibition.

Using this system of communication, the integrated circuit of the transponder, regardless of its type (read/write or read-only), can detect the appearance or the disappearance of the energy field, the electromagnetic or infra-red type, emitted by the interrogation component. In fact, in the case of an integrated circuit of the active type, this circuit is intelligent enough to detect the changes in the field, while in the case of an integrated circuit of the passive type, this field is a necessary condition for its functioning.

The inhibition command is made by a change in the electromagnetic-or infra-red field. This change consists in a practical manner in creating breaks in the field.

Preferably, these breaks will be applied according to a sequence as a function of the reception windows of the integrated circuit of the transponder.

In this manner, the inhibition command is transmitted to a particular integrated circuit or to a group of integrated circuits within an application, for example.

The inhibition command transmitted in this manner makes possible the prevention of any modification of the information in the memory of the integrated circuit.

The system according to the invention makes it possible to use the economical transponders at a very low cost since they can be only manufactured based on passivetype integrated circuits, i.e. read-only, not using any demodulation and decoding circuit which normally equips an integrated circuit of the read-write type, nor any control circuit and inhibition mechanisms to lead to the inhibition.

Other particularities and advantages of the invention appear in reading the description made as a non-restrictive example in referring to the attached figures which show: Figure 1, organization of the memory of the integrated circuit of a transponder, Figure 2, a diagram of the principle showing the transmission of an inhibition command between the interrogation component and an economical transponder.

In the following description of the communication system, a radiofrequency (RF) communication system is described. However, the invention is not limited to this type of system and can be applied in the same manner to an infra-red communication system.

In the case of an RF communication system, a bridge rectifier integrated into the transponder makes possible the extraction of a supply power from the radiofrequency signals generated by the interrogation component. When the level of the voltage obtained at the terminals of the transponder reaches a predetermined value which corresponds to the supply voltage of the transponder, the transponder "wakes up" or initializes and then begins to send its data to the interrogation component The data intended to be communicated to the interrogation component are stored in at least one non-volatile memory MNV of the integrated circuit of a transponder. This non-volatile memory is electronically programmable, of the EEPROM type, and/or inactive, of the ROM or PROM type. The organization of this memory MNV is shown in Figure 1.

The non-volatile memory of the integrated circuit is divided into several zones in which the data are stored. The first zone, designated ATR (from the English term "Answer to Reset"), consists of several bytes, defines a message which combines the characteristic information of the exchange protocol and the integrated circuit. This message is intended to be emitted towards the interrogation component in response to the initialization of the transponder.

Other zones CMDI, TMID, APID, TID, and CRC can be planned in order to define respectively the manufacturer of the integrated circuit, the manufacturer of the transponder, the application, the type of transponder, or an error control circuit, for example.

The name of the manufacturer of the integrated circuit or that of the transponder is useful in order to contend with the manufacture of similar chips or transponders.

The TID information is important because some data is registered in a memory of the interrogation component as a function namely of the type of transponder used. Other zones can, in addition, be planned for the storage of other data.

The message of the ATR zone consists, in particular, of MOD information characteristic of the inhibition mode of the integrated circuit. Preferably, this information is placed at the head of the ATR in order to accelerate the handling of the reading of the contents of the memory of the integrated circuit and in order to make easier the decoding by the interrogation component.

Four types of inhibitions are possible: the total permanent inhibition, the partial permanent inhibition, the temporary total inhibition and the temporary partial inhibition.

In order to define whether the integrated circuit is inhibited or not and, if yes, to determine its mode of inhibition, the MOD information is preferably coded in 3 bits. The applications of the different modes of inhibition and their commands are explained in more detail in the following.

Another information MS of the ATR message makes it possible to define the size of the memory of the integrated circuit. In an embodiment example of the invention, this information can, for example, be coded in 3 bits. Thus, using this information, the interrogation component can improve its dialogue with the integrated circuit of the transponder. Thus, these memory size values could be coded consisting of for example between 80 bits and 16 kbits. ,n an advantageous manner, these values, corresponding to the coded MS information, are stored in a memory of the interrogation component.

On the other hand, the RR information makes it possible to determine the manner in which the transmission of the data will be carried out between the integrated circuit and the interrogation component. In fact, in order to avoid certain types of radioelectric interference, of industrial origin and occurring cyclically, it is advantageous to carry it out in a way so that the transmission of the contents of the memory of the integrated circuit are either done in a repetitive manner, separated by the pause intervals, again called stand-by periods PV.

During these stand-by periods PV, the contents of the memory of the integrated circuit can not be read. The duration of these periods is defined to be'fixed or variable manner. As a result, a bit of the ATR makes it possible to inform the interrogation component of the type of repetition programmed for transmission of data.

Thus, when the bit which codes the RR information is at 0, for example, the duration of the stand-by periods PV is fixed and corresponds, for example, to that of one byte. The reception windows FE of the integrated circuit, during which the integrated circuit is attentive, i.e. ready to detect an inhibition command from the interrogation component, are defined within these stand-by periods PV. The instant of the opening of each reception window FE is defined by the position of a bit of the byte of the corresponding stand-by period PV.

In the opposite case where the bit coding the RR information is at 1, the duration of these stand-by periods PV is variable and has a length between one bit and that of 16 bits. The reception windows FE of the integrated circuit are, in addition, defined in a pseudo-random manner within these stand-by periods.

The role of the RR information is explained in a more detailed manner in the following.

Finally, the DR information determines the capacity of the transmission, i.e. the speed of the exchanges between the transponder and the interrogation component. It can be coded in 2 bits, for example, so as to allow the defining of four different values of the maximum speed of transmission tolerated by the integrated circuit according to the application to be executed. The values of the maximum speed tolerated corresponding to each code are advantageously registered in a memory of the interrogation component.

Using the knowledge of the value of the maximum transmission speed of the transponder, the interrogation component can adjust its transmission speed relative to this maximum speed according to the radioelectric environmental conditions. This allows, for example, the avoidance of the problems of collision between the responses of several transponders and freedom from cyclic interference.

Thus, in the case where the electromagnetic field is perturbed, the component can lower the speed of transmission in order to reduce possible errors of interpretation of the messages.

On the contrary, the speed can be increased up to the maximum tolerated speed in order to reduce to a minimum the time of transmission, when the environment is favorable for it, i.e. when it is not subjected to many perturbations. In the embodiment example, the maximum speed of transmission can be equal to 1655 bits, or 3310 bits, 13242 bits or 26484 bits per second.

Thus, in the transportation applications, i.e. during a roadway toll for example, the integrated circuit will have to necessarily communicate its data with a maximum high speed, for example, a maximum speed of 26484 bits per second. On the other hand, during a service contract, this maximum speed does not need to be as high since the product label is stationary; it can thus be fixed at 1655 bits or 3310 bits per second, for example, in this case.

The characteristic information defined in the ATR message is preferably transmitted to the interrogation component for emission/reception in response to the initialization of the transponder. The dialogue between the interrogation component and the transponder is then done in the conventional manner in the form of questionsresponses.

The diagram of Figure 2 shows a principle of transmission of an inhibition command of the integrated circuit of a transponder by the interrogation component.

The inhibition command comes to turn off at least once the electromagnetic field emitted by the interrogation component, for a short period. The speed of the command is shown in Figure 2 by the time line mI. The command, as is shown there, consists of disconnect pulses PCI1, PCI2, PCI3 of the electromagnetic field. The number of pulses is ordinary, it is predetermined as a function of each type of integrated circuit. In the example shown in Figure 2, this number is equal to three. Thus, when the integrated circuit has detected the three PCI pulses to stop the electromagnetic field, it is automatically inhibited.

However, these disconnect pulses must not be made at any arbitrary moment. In fact, it is necessary to change the electromagnetic field at the precise moments of reception of the integrated circuit to be inhibited. These moments of reception are defined by the reception windows FE. Their duration is preferably equal to that of one bit. They are determined from the stand-by periods PV, which are themselves defined in the RR information of the ATR message.

The RR information in fact consists of at least one bit which makes possible the definition of the stand-by periods PV designated to interrupt the sensing of the content of the memory of the integrated circuit. These stand-by periods have a set length of time or.

are variable according to the value of the bit coding the RR information.

In the example shown in Figure 2, in order to simplify comprehension, the standby periods PV are of a set length of time. In this case, the length of each stand-by period PV corresponds to the length of one byte, one bit having, in a known way, a well defined length.

In an advantageous way, the first stand-by period PV1 is created from the characteristic CRC information of the error control circuit of the integrated circuit in a manner so that the first stand-by period, and as a consequence the stand-by periods following it, are different from one transponder to the next.

The reception windows FE of the integrated circuit then open at the predetermined moments, within the stand-by periods PV, in a manner so as to make the integrated circuit attentive to the inhibition command signals sent by the interrogation component.

The length of each reception window corresponds to that of one bit. The sequence which defines the moments of opening the reception windows is given by the position of one bit of a stand-by period. In an advantageous way, the position of this bit will be different for each of the three successive stand-by periods used for the inhibition.

This sequence is not only programmed in the integrated circuit during its manufacture, but also registered in a memory of the interrogation instrument as a function of the type of transponder (TID information) and the RR information which defines the length of the stand-by periods PV.

Then, in the example shown in Figure 2, the three reception windows FE of the integrated circuit are initiated respectively on the bits 2, 6 and 4 of the three successive stand-by periods PV1, PV2, PV3, of fixed length.

This signifies that, when the bits are numbered from 0 to 7, the first reception window FE1 is initiated at the end of a length equal to bits, n being the number of the bit corresponding to the moment of the opening of the window FE1, i.e. at the end of a length of 3 bits in the first stand-by period PV1. In the same way, the second reception window FE2 is open at the end of the length of 7 bits in the second stand-by period PV2 and the opening of the third reception window FE3 in place at the end of a length of 5 bits in the third stand-by period PV3.

As a result, so that the integrated circuit can detect the three inhibition commands sent by the interrogation component in the form of disconnect pulses PCII, PCI2, PCI, it is necessary for these disconnect pulses to be executed during the three corresponding reception windows FE1, FE2, FE3, defined respectively by the bits 2, 6 and 4 of the successive stand-by periods PV1, PV2, PV3.

The example shown is not restrictive; there are many embodiment variations.

Thus, it is possible that one stand-by period PV can contain several reception windows FE of the integrated circuit Moreover, the reception windows of the integrated circuit can be defined, successively or non-successively, within the many stand-by periods.

According to another embodiment variation, the length of the stand-by periods PV can be variable. In this case, it has a length between one bit and 2 bytes.

The length of each stand-by period varies in fact according to a sequence determined in a pseudo-random manner. At a first time, the integrated error control circuit sends information to the interrogation component which defines the length of the first stand-by period PV1 and the moment of its initiation. The length of the following stand-by periods are then determined according to a pseudo-random sequence stored in a memory of the interrogation component, as a function of the type of transponder, i.e. as a function of the TID information, and programmed in the integrated circuit during its manufacture. This sequence is, for example, the following: 5 bits, 13 bits, 1 bit, 9 bits, 4 bits, 12 bits, 16 bits, 8 bits, 7 bits, 15 bits, 3 bits, 11 bits, 6 bits, 14 bits, 2 bits, and bits.

As a result, when the length of the first stand-by period is defined by 9 bits, for example, the following length will have a length of 4 bits and then the rest. In this manner, the stand-by periods are all different from one transponder to the next.

The reception windows FE, having a length corresponding to that of one bit, are open within the stand-by periods PV, at a moment defined by the position of a bit.

According to the length of the stand-by period PV, the bit defining the moment of the opening of the reception window FE is different. This bit is selected in a pseudo-random manner, according to a sequence programmed in the integrated circuit during its manufacture, and in memory in the interrogation component as a function of the transponder type (TID) and the type of the programmed repetition This sequence is depicted in the table below: length of the stand-by period PV initiation bit of the reception window FE 16 8 1 0 2 0 3 1 4 2 3 6 2 7 3 8 4 9 4 11 12 6 13 7 14 6 7 Thus, when the length of the stand-by period of the integrated circuit corresponds to a length of 14 bits for example, the integrated circuit is pre-programmed, during its manufacture, so that the corresponding reception window opens on the sixth bit. In addition, when the inhibition is temporary, its length can be linked to a time delay commanded by the integiated circuit. This time delay is commanded by an internal clock of the integrated circuit. In the case where the integrated circuit of the transponder is an integrated circuit of the passive type, the RF signals received allow the activating of the generating circuit of the internal clock.

According to a variation, it is possible to make it so that it is the interrogation component which commands the start and the end. of the inhibition of the integrated circuit. In this case, the end of the inhibition can, for example, be commanded in the same manner, by one or more manipulations of the electromagnetic field.

Using this system, the inhibition command is transmitted to the integrated circuit without having recourse to an ordinary writing into its memory, though it is becoming possible to inhibit economical transponders made based on the integrated circuits of the passive type, i.e. read-only for example.

The applications of this system are numerous, reference will be made to only a few in order to make it easier to understand the invention.

In the case of the sale or storage of labeled merchandise, such as computers or photocopiers, for example, it can be advantageous to inhibit the integrated circuit of the transponder, at the time of payment, for example, in order to not set off the detector alarm located at the exit of the store, or at the time of leaving the warehouse so that the integrated circuit may not be activated during transport. In this case, the inhibition made is preferably temporary. It in fact appears useful to be able to reactivate the integrated circuit of the transponder in order to carry out later maintenance operations, for example.

The temporary inhibition can be total, and in this case the detector located at the exit of the store, for example, will not be able to detect anything.

However, in some situations it is preferable to command a temporary partial inhibition of the integrated circuit. In effect, using this partial inhibition, the integrated circuit can resend a message indicating that it exists but that it is momentarily inhibited.

In this way, the detector located at the exit of the store, or the warehouse, can detect the passage of the labeled product without activating the alarm. The detector can thus monitor the number of products sold, for example, this number can be, in particular, used to monitor the accounting of the warehouse.

The integrated circuit is then reactivated either at the end of a certain time delay period by an internal clock, or by an interrogation component used later to carry out maintenance operations, for example.

During these maintenance operations, the interrogation component can thus read, in the contents of the memory of the integrated circuit, information such as the date of the end of the guarantee, for example. In addition, if the integrated circuit allows it, the interrogation component can command the writing, in a memory zone, of information involving the date of the operation or the operations carried out on the product, for example.

Another application involves the sending of parcel post containing the labeled products. In this case, it can be favorable to inhibit the integrated circuit of the transponder in a temporary or permanent manner during the reception of the parcel by the addressee, in a way to make it possible to verify that the parcel has arrived at the destination and to thus facilitate the management of possible complaints.

Finally, in other situations, it is necessary to inhibit the integrated circuit of a transponder in a permanent manner in order to prevent any unauthorized reuse of the labeled product.

The permanent inhibition can be partial in a manner so that the integrated circuit permanently emits a message intended to indicate its presence and the fact that it is unable to do anything. The partial inhibition thus allows the verification that the integrated circuit is not inactive.

The permanent inhibition can, in addition, be total. In this case, the integrated circuit does not do anything and it can not be differentiated from an inactive integrated circuit in any case.

Claims

1. System of communication between a component of an emission/reception interrogator, fitted to emit an energy field, and at least one transponder including an integrated circuit having a memory, wherein in response to initialisation, the transponder sends a carrier message, in particular, of information characterized by its inhibition mode, and information which defines the duration of stand-by periods between two messages, during which the interrogation component is ready to send one or more inhibition command(s) based on a registered mode.

2. System of communication according to claim 1, characterized in that after the message is sent, the transponder sends information which allows it to be identified, in particular, information characteristic of the transponder type.

3. System of communication according to one of claims 1 to 2, characterized in that the integrated circuit opens at least one reception window, inside the stand-by periods, during which it is ready to receive the command S: 20..signals of inhibition sent by the interrogation component. S

4. System of communication according to any one of claims 1 to 3, characterized in that the instant of the opening of the reception window(s) is registered in a memory of the interrogation component as a function of the type of transponder and the information which defines the duration of the stand-by 25 periods.

System of communication according to any one of claims 1 to 4, characterized in that the reception widows are opened successively or non- successively within one or more stand-by periods.

6. System of communication according to any one of claims 1 to characterized in that the stand-by periods of the integrated circuit have a fixed -7ii or variable duration. F:,mare\GABNODEL%57677-98.doc -12-

7. System of communication according to any one of claims 1 to 6, characterized in that when the duration of the stand-by periods is fixed, it corresponds preferably to that of one byte, and the instant of the opening of each reception window is defined by the position of one predetermined bit of the byte which defines the corresponding stand-by period.

8. System of communication according to any one of claims 1 to 6, characterized in that when the duration of each stand-by period is variable, it is between one bit and 16 bits and is determined according to a pseudo-random sequence, and the moment that each reception window opens is defined by the predetermined position of a bit of the corresponding stand-by period according to a pseudo-random sequence.

9. System of communication according to any one of claims 1 to 8, characterized in that an inhibition command consists in extending the energy field emitted by the interrogation component for a short period.

10. System of communication according to any one of claims 1 to 9, e .characterized in that the interrogation component sends a predetermined number of inhibition commands, in the form of disconnect pulses within the reception windows.

11. System of communication according to any one of claims 1 to characterized in that the different inhibition modes of the integrated circuit of a 25 transponder are: the total permanent inhibition, the partial permanent inhibition, the temporary total inhibition and the temporary partial inhibition.

12. System of communication according to any one of claims 1 to 11, characterized in that when the inhibition is temporary, the interrogation component commands the start and the end.

13. System of communication according to any one of claims 1 to 11, characterized in that when the inhibition is temporary, its length is a time delay JRAi by the internal clock of the integrated circuit. -13-

14. System of communication according to any one of claims 1 to 13, characterized in that it consists of a radiofrequency communication system.

15. System of communication according to any one of claims 1 to 13, characterized in that it consists of an infra-red communication system.

16. System of communication according to any one of claims 1 to characterized in that the integrated circuit is the passive, read-only type.

17. System of communication substantially as herein described with reference to the accompanying drawings. DATED: 20 March, 2000 PHILLIPS ORMONDE FITZPATRICK Attorneys for: GEMPLUS S.C.A. U *g *o o•