FR2776409A1 - System and procedure for identifying products with a label, which is for use in stock management - Google Patents

Abstract

Each label comprises a random code generator (IDAn) and a memory for registering said code. The random code is transmitted to a reader on request. The reader includes a memory for registering said random codes and in subsequent procedure steps can then identify individuals items amongst a stock of identical items. The random codes are transmitted either simultaneously or at random times.- DETAILED DESCRIPTION - Subsequent procedure steps may include transmission of a random code to the n electronic labels and exchange of information with the label having the matching random code to that transmitted. The codes and requests between labels and reader are transmitted electromagnetically

Description

SYSTEM AND METHOD FOR IDENTIFYING PRODUCTS BY

RANDOM IDENTIFIER

  The present invention relates to the electronic labeling of products using labels each consisting of an electronic circuit disposed on a support adhering to the product to be identified. It relates more particularly to a system and method which makes it possible to identify with such labels all the products situated in the field of an interrogation device whatever the number of products in the field and to then dialogue with each of the

labels.

  Products, particularly those of mass consumption, are identified by bar codes which are read and analyzed at the time of checkout so as to automatically determine the price using a computer system. These bar codes are printed on the product packaging and define, for example, the name of the manufacturer and the type of product. These bar codes have a purely passive role and cannot be used to control the payment of the product, the dates of

  expiration, stock status, theft, etc.

  Also, to fulfill these new functions, it has been proposed to use active electronic labels consisting of a miniature electronic circuit (or electronic chip) carried by a support adhering to the product to be identified. These labels can be interrogated remotely by an interrogation and reading device and answered by

appropriate messages.

  These electronic labels record a number or code identifying the type of product such as a package of

  identical rusks, identical butter wafer ...

  as well as other codes indicating the date of

  expiration, name of manufacturer, etc.

  To be able to identify and count the products of the same type located in the field of an interrogation and reading device, it is necessary to discriminate the responses coming from the same product

  by a process or system called anti-collision.

  Indeed, the interrogation carried out by the reading device challenges all the identical labels located in the field and the response of the latter can occur at the same time, from collision and

unable to read.

  To overcome this problem, several so-called anti-collision systems and methods have been proposed which can be classified into two categories: response system

  synchronous or asynchronous response system.

  In the synchronous response system, the tags respond simultaneously from a synchronization instant or "top" determined by the reading device and each provide their identification number or identifier according to a particular coding which makes it possible to detect the collision. An iterative algorithm implemented by the reading device makes it possible to identify each label and thus to know the list of identifiers. This system has the drawback of only working with all different identifiers and can therefore hardly be used in applications such as

large distribution.

  In the asynchronous response system, the tags respond from a synchronization top that defines the start of a long time window during which the reader receives the responses from the tags. Each label responds after a random duration from the synchronization signal by transmitting its identifier to the reading device. As the identifiers are detected, the reading device "inhibits" or "turns off" each label identified for

  prevent her from responding a second time.

  The reading device knows the list of all the products corresponding to the same identifier as soon as the

  reading device no longer receives a response.

  This system makes it possible to operate with identical identifiers but it is not possible to interact with each label in a unique manner after having recognized it. The object of the present invention is therefore to implement a system and method for identifying products of the electronic label type which makes it possible to identify identical products in the detection field of a reading device and then to dialogue with each electronic label of the identified product. This object is achieved by the transmission by each electronic label to the device for reading a random code in response to an interrogation of the latter, this random code then being used to identify the product individually during the whole

  duration of the transaction relating to this product.

  According to another characteristic of the present invention, these transmissions of random codes

  can be synchronous or asynchronous.

  According to another characteristic of the present invention, the length of this random code is determined as a function of the number of identical products capable of being identified and this length can therefore be different from a type of product.

to another.

  According to yet another characteristic of the present invention, the ambiguity resulting from the transmission of two identical random codes can be resolved by the use of an additional identification code

  in the case of an asynchronous transmission.

  The invention therefore relates to a system for identifying a number n of products using electronic labels adhering to each product and interrogable remotely by an interrogation device, each electronic label comprising at least one memory for recording a

  identification code product ID, a transmitter-

  receiver for receiving information from the interrogation device and transmitting the identification code to said interrogation device, and the interrogation device comprising a transceiver for simultaneously transmitting interrogation signals to the n labels and receiving said identification codes identification of the labels and a microprocessor to analyze the identification codes received and thus identify the n products, characterized in that: - each label comprises, in addition, a generator of random codes IDAn with N digits and a memory for recording said IDAn random code, said random code being transmitted at least once to said interrogation device at the latter's request, and - said interrogation device further comprises a memory for recording the IDAn random codes transmitted by electronic tags and thus identify by this random code each product

among n products.

  In the case of an asynchronous response system, each label further comprises a generator of random durations for defining pauses during which the electronic label does not transmit said random code from an instant determined by said

interrogation device.

  The invention also relates to a method for implementing the system, characterized in that it comprises the following steps consisting in: (a) subjecting the n labels to an electromagnetic field, (b) calculating in each label the random code IDAn and save it in a memory, (c) transmit said IDAn random code to said interrogation device at the request of the latter, (d) save said IDAn random code in a

  memory of the interrogation device.

  It can further comprise the following additional steps consisting in: (e) transmitting said random code IDAn to the n electronic labels by the interrogation device, and (f) exchanging information with the electronic label which corresponds to said transmitted random code. In the case of an asynchronous response system, the method may further comprise the following additional steps consisting in: (g) transmitting with the random code IDAn a second IDR code identifying the rank of the transmission in the sequence d 'interrogation, (h) disregard in the interrogation device codes (IDA + IDR) which are identical during the first transmission, (i) retain the code (IDA + IDR +1) received first during the next transmission to identify the corresponding label and inhibit this label to prevent it from transmitting in the next step, (j) repeat steps (g) and (i) until the labels with the same are inhibited coded

(IDA).

  Other features and advantages of this

  invention will appear on reading the description

  following of a particular embodiment,

  said description being made in relation to

  attached drawings in which: - Figure 1 is a diagram showing the system according to the invention, - Figure 2 is a time diagram showing the chronological sequence of the interrogation and the responses to the interrogation in an asynchronous response system , - Figure 3 is a diagram illustrating a response discrimination algorithm, - Figure 4 is a diagram illustrating a response discrimination algorithm to obtain perfect discrimination, and - Figure 5 is a simplified block diagram of a label electronic presenting

  features of the present invention.

  The invention will be described in the case of an asynchronous response system but it is also applicable

  to a synchronous response system.

  All the operations or steps of the method are initialized by an interrogation and reading device 10 provided with a transmit-receive antenna 12, a keyboard 16 and a dial 14, the assembly being under control of an operator not shown. The operator places the device 10 in front of a shelf 18 in which are stored products 20 of different types: packets of rusks, packets of

sliced bread, etc ...

  Each product 20 is provided with an electronic label 22 comprising a transmission-reception antenna, not shown. Each electronic label 22 mainly comprises a microprocessor and at least one register which contains various codes allowing for

example:

  - identify the product, - identify the manufacturer, - indicate the expiration date,

  - activate anti-theft information.

  According to the invention, this register is provided for recording an IDA random code with N digits which is calculated by the microprocessor according to a conventional program. According to the invention, this register can also be provided for recording the value N. Being an asynchronous response system, the microprocessor is designed to calculate not only a random IDA code but also, as is known, a random duration "d" at the end of which

  the label will transmit its response to the query.

  The antenna 12 emission-reception diagram is designed to cover all the shelving 18 with an electromagnetic field, which makes it possible to interrogate all the

22 labels of this shelving.

  The interrogation device 10 comprises at least one microprocessor which performs, according to determined programs, a certain number of operations according to the choices defined by the operator. Certain operations are known in the prior art but others are specific to the present invention and will be described

  below in relation to Figures 2, 3 and 4.

  The first operation or step consists in starting up the interrogation device 10, which corresponds to step 30 (FIG. 2) of initialization POR of the interrogation device 10 and of the labels 22 "lit" by the radiation of The antenna 12. This step 30 triggers in each label a second step 32 consisting in calculating a random identification code IDA1 for the label 1, IDA2 for

  label 2 to IDAn for order label n.

  This IDA code is recorded in the register provided for this purpose. This step 32 also triggers in each label the start of a generator of random durations or pauses, duration during which the label transmits no message from which the term of random pause. The random duration generator can be produced by calculating a random number using the microprocessor, this number then being recorded in an up / down counter which provides a signal when it goes to zero for example. This random duration generator can provide

  successively random lengths of breaks.

  The third step 34 consists in the interrogation device 10 transmitting a TOP synchronization signal to all the labels 1 to n, this

  which starts counting up / down counters.

  As soon as one of the pause generators provides a signal, it transmits to the interrogation device 10 at least the random code IDA (step 36). Thus, in the example of FIG. 2, the labels of order 1, 2, 5 ... n, will respectively transmit the codes IDA1, IDA2, ... IDAn only at times d1, d2, ... , dn after the appearance of the TOP synchronization signal. These codes IDA1, IDA2, ..., IDAn will be retransmitted again after the second break, for example after a break of 2 for the order label 2, break of 2 which corresponds to a second cycle of random breaks , cycle which is for example initialized in each

  label by transmitting the IDA code.

  These IDA codes are received by the interrogation device 10 and are recorded in a memory provided for this purpose (step 38) so that each corresponding label could be re-interrogated

separately using this code.

  During each subsequent cycle of random breaks, IDA codes that have already been received and saved are no longer taken into account. When the number of IDA codes received during a cycle corresponds to the IDA codes

  saved, the identification operation is completed.

  In addition to the transmission of IDA codes, the system can be provided to simultaneously transmit the product identification code ID as indicated

in figure 2.

  In FIG. 3, steps 30, 34 and 38 are performed by the interrogation device 10 while steps 32 and 36 are performed by all of the n labels. At the end of step 38, the device 10 has identified each label by an IDA code, associated or not with an identifier ID of the product and it can therefore continue to interrogate each label separately with the corresponding IDA code to read other information such as expiration date or to record in the label other information such as a muting code which, for example, orders the label

asked not to transmit anymore.

  Such a system only works properly if two or more tags do not draw the same IDA code, which would lead to errors. To reduce the probability of such a malfunction, the invention provides for choosing a number N such that the number of possible random codes is very high compared to the number n of tags to be interrogated. It is therefore very unlikely that two identical IDAs will be transmitted during an interrogation cycle.

of a product type.

  According to the invention, this number N of the digits of the code

  Random IDA may vary from application to application.

  Thus, the number N can be determined once and for all at the time of manufacture of the label according to determined criteria. It can also be determined at each interrogation sequence by the operator based, for example, on an estimate of the number

labels to query.

  Another way of choosing N is to carry out several successive interrogation tests with increasing values of N until no longer obtaining

Identical IDA codes.

  To ensure perfect discrimination, the invention proposes to add a so-called recurrence identifier IDR which indicates the number of transmissions carried out by

a label.

  The diagram in FIG. 4 shows the algorithm implemented by each label. Upon receipt of the POR signal by each label (step 40), the latter calculates the random number IDA and starts the generator of random durations (step 42). On receipt of the TOP synchronization signal (step 44), each label associates with the random code IDA, an IDR code = 1 indicating that it will be a first transmission (step 46). When the first random pause ends (step 48), the IDA and IDR are transmitted in one word (step 50). During the next random pause (step 52), the label increases by one unit the value of the IDR which takes the value (IDR + 1 = 2). This value is transmitted with the IDA in one word at the end of the

  next random pause (steps 54 and 56).

  Steps 52, 54 and 56 are repeated (link 58) by each label as long as the latter does not receive from the interrogation device an inhibition signal 60 ordering it to no longer transmit its code

(IDA + IDR).

  This inhibition signal could be transmitted to each label which has just been identified by a code (IDA + 1) different from one to the other so that the only labels to continue to transmit would be those for which the codes (IDA + 1) are identical, which makes it possible to identify them one after the other after the following random breaks and to

inhibit upon identification.

  However, according to the invention, following the identification of each label by an IDA code or (IDA + IDR), the inhibition signal (60) will be used during identification only if several labels have the same code (IDA + IDR) and will only be

  transmitted only to the label which has just been identified.

  By adding an IDR code to the IDA code, the label creates a new random code (IDA + IDR) which changes to

  each transmission but with an IDA fixed part.

  Thus, if three identical codes (IDA + 1) are transmitted simultaneously after a first random pause, none will be taken into account by the interrogation device because the latter cannot identify any of the three labels. At the end of the second random pause, the interrogation device will most likely receive the three identical codes (IDA + 2) at different times, which will make it possible to retain the first arrival by assigning it the code (IDA + 2) and to reject the two others who will be discriminated one at the third random pause by the code (IDA + 3) and the other at the fourth random pause by the code

(IDA + 4).

  This method of adding the IDR code indicating the rank of the transmission can also be implemented in the case where, for example, three identical codes (IDA + 1)

  are transmitted, not simultaneously as described above

  on it, but after different random breaks.

  In this particular case of the previous one, the interrogation device will retain the first code (IDA + 1) which is received and will reject the other two which will be discriminated, one at the second random pause by the code (IDA + 2) and the other on the third break

random by code (IDA + 3).

  The description which has just been made makes it possible to define

  a product identification process, characterized in that it comprises the following steps consisting in: (a) subjecting the n labels to an electromagnetic field (30), (b) calculating (32) in each label the random code ( IDAn) and save it in a memory, (c) transmit (36) said random codes (IDAn) to said interrogation device (10) at the request of the latter (34), (d) record (38) said codes random codes (IDAn) in a memory of the interrogation device, said random codes (IDAn) identifying

each a label or product.

  When each label has been identified by the random code, the method can be completed by the following additional steps consisting in: (e) transmitting by said interrogation device said random code (IDAn) to the n electronic labels, and (f) exchanging information with the electronic tag which corresponds to said random code transmitted. In applications where perfect discrimination is sought, the method is completed by the following additional steps consisting in: (g) transmitting with the random code (IDAn) a second code (IDR) identifying the rank of the transmission in the sequence d 'interrogation, (h) disregard in the interrogation device codes (IDA + IDR) which are identical during the first transmission, (i) retain the code (IDA + IDR +1) received first during the next transmission to identify the corresponding label and inhibit this corresponding label to prevent it from transmitting, during the next step, (j) repeat steps (g) and (i) until the labels having the same code

(IDA).

  The invention is also applicable to an interrogation system with synchronous responses; indeed, in this case, the electronic tags simultaneously transmit their random code, which makes it possible to identify them one after the other by assigning them this random code in the memory of the interrogation device. However, this synchronous response system does not allow the use of an IDR transmission rank code to obtain a

perfect discrimination.

  The invention also relates to an electronic label which comprises (FIG. 5) a first memory 60 in which the identification code of the type of product is recorded as is known but also a code defining the expiration date, a code identifying the manufacturer of the product or any other code defining information of interest. To implement the present invention, the label must further comprise a generator 62 of IDA random codes as indicated above and a

  second memory 70 to store this random code.

  The random code generator IDA can also include a third memory 64 for storing the number N of digits of the random codes as indicated above. Finally, in the case of an asynchronous response system, the label comprises a generator of random lengths of breaks which can be produced by a second generator 66 of random codes whose codes

  load an up / down counter 68 as indicated above

  above. Such a generator of random duration codes can be combined with the first generator 62 of

IDA random codes.

  This label 22 also includes a transmitter / receiver 72 and an electronic device for supplying and

  command 74 of the different elements of the label 22.

  The rank of the transmission of the IDA code is given by a

counter 76.

  The functions of the various elements 62, 64, 66, 68, 74 and 76 are preferably performed by a microprocessor.

Claims (17)

  1. System for identifying a number n of products (20) using electronic labels (22) adhering to each product and interrogable remotely by an interrogation device (10), each electronic label (22 ) comprising at least a memory for recording a product identification code (ID) (20), a transceiver for receiving information from the interrogation device (10) and transmitting the identification code to said interrogation device , and the interrogation device (10) comprising a transceiver for transmitting interrogation signals to the n labels and receiving said label identification codes (22) and a microprocessor for analyzing the identification codes received and thus identify the n products, characterized in that: - each label comprises, in addition, a random code generator (IDAn) with N digits and a memory for recording said random code (IDAn), said code of random being at least transmitted to said interrogation device (10) at the latter's request, and - said interrogation device further comprises a memory for storing the random codes (IDAn) transmitted by the electronic tags and thus identify by this random code each product among n products.   2. System according to claim 1, characterized in that said random codes (IDAn) are transmitted   simultaneously with the interrogation device (10).   3. System according to claim 1, characterized in that each electronic label (22) further comprises a generator of random durations for defining pauses during which the electronic label does not transmit said random code from an instant determined by said interrogation device (10). 4. System according to claim 1, 2 or 3, characterized in that the number N of digits of the random code (IDA) is determined as a function of the number n of products of the same category.   5. System according to claim 4, characterized in that the number N of digits of the random code (IDA) is determined by the system operator and transmitted to the n electronic labels.   6. System according to claim 4, characterized in that the number N of digits of the random code (IDA) is determined by the interrogation device by a   series of tests using an increasing number N.   7. System according to any one of the claims   above 3 to 6, characterized in that each label further comprises a counter of transmissions carried out to supply a recurrence code (IDR) identifying the rank of the transmission, said recurrence code (IDR) being transmitted with the random code (IDAn).   8. Method for implementing the system according to one   any one of claims 1 to 7, characterized in that   that it comprises the following steps consisting in: (a) subjecting the n labels to an electromagnetic field (30), (b) calculating (32) in each label the random code (IDAn) and saving it in a memory, ( c) transmitting (36) said random codes (IDAn) to said interrogation device (10) at the request of the latter (34), (d) recording (38) said random codes (IDAn) in a memory of the device interrogation, said random codes (IDAn) identifying each a label or product.   9. Method according to claim 8, characterized in that step (c) consists in simultaneously transmitting said random codes to the interrogation device. (IDAn).   10. Method according to claim 8, characterized in that step (c) consists in transmitting said random code (IDAn) after a pause of random duration counted from an instant defined by the interrogation device. 11. Method according to claim 7, 8, 9 or 10, characterized in that it further comprises the following additional steps consisting in: (e) transmitting said random code (IDAn) to the n by the interrogation device electronic tags, and (f) exchanging information with the electronic tag that corresponds to said random code transmitted. 12. Method according to claim 10, characterized in that it further comprises the following additional steps consisting in: (g) transmitting with the random code (IDAn) a second code (IDR) identifying the rank of the transmission in the interrogation sequence, (h) disregard in the interrogation device the codes (IDA + IDR) which are identical during the first transmission, (i) retain the code (IDA + IDR +1) received on first during the next transmission to identify the corresponding label and inhibit this corresponding label to prevent it from transmitting, during the next step, (j) repeat steps (g) and (i) until inhibition labels with the same code (IDA).   13. Electronic label (22) for implementing the system and method for identifying a number n of products comprising a transceiver (72), a first memory for storing an identification code ID and a device for control (74), characterized in that it further comprises - a generator (62) of IDA random codes with N digits, and - a second memory (70) for storing the code   random IDA supplied by the generator (62).   14. Electronic label according to claim 13, characterized in that it further comprises a third memory for recording the number N of IDA random code digits.   15. Electronic label according to claim 13 or 14, characterized in that it further comprises a   generator (66, 68) of random lengths of breaks.   16. Electronic label according to claim 15, characterized in that the generator (66, 68) of random lengths of breaks comprises a generator (66) of random codes and an up / down counter (68) which is charged by the generator (66).   17. Label according to claim 15 or 16, characterized in that it further comprises a counter 76 indicating the rank IDR of the transmission carried out.