Method for remotely interrogating tags, and station and tag implementing said method
First Claim
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1. A method for remotely identifying electronic tags from a station, each of said tags having its own code constituted by digits, in which identification of a tag comprises the steps of:
- (a) determining if tags exist having one of possible digits at a certain digit position or rank in their code;
(b) prior to a last digit position, determining if tags exist for a given digit, storing this digit and then temporarily blocking all other tags, and returning to step (a) for the next digit position;
(c) at a last digit position, determining if a tag exists for a given digit, storing this digit and reconstituting a tag code using said stored digits.
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Abstract
A method is provided for remotely identifying electronic or radio frequency tags, typically those used to mark articles, from a station, each of the tags having its own code constituted by digits, in which identification of a tag comprises the steps of issuing interrogation signals from the station for different digit positions and employing procedures to accelerate tag identification once a first tag has been found. A suitable station and tag are also provided.
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Citations
32 Claims
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1. A method for remotely identifying electronic tags from a station, each of said tags having its own code constituted by digits, in which identification of a tag comprises the steps of:
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(a) determining if tags exist having one of possible digits at a certain digit position or rank in their code;
(b) prior to a last digit position, determining if tags exist for a given digit, storing this digit and then temporarily blocking all other tags, and returning to step (a) for the next digit position;
(c) at a last digit position, determining if a tag exists for a given digit, storing this digit and reconstituting a tag code using said stored digits. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
determining if tags exist having, at a digit position in their code, a digit that is comprised in a set of digits;
if such tags do exist, then determining whether tags exist having one of the digits of said set at said digit position in their code; and
if such tags do not exist, determining if tags exist having one of the digits of the complementary set of said set at this digit position of their code.
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6. The method according to claim 5, wherein said set contains half of the possible digits.
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7. The method according to claim 5, wherein said code comprises digits to a base 10, and in which said set of digits comprises the digits {0, 1, 2, 3, 4} or {5, 6, 7, 8, 9}.
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8. The method according to claim 1 wherein the step consisting in determining if tags exist having one of the possible digits at a digit position in their code comprises:
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at least two steps consisting in determining whether tags exist that have, at a digit position in their code, a digit that is comprised in a set of digits, the cardinal number of a set in one of said steps being lower than the cardinal number of the set in the preceding step;
a step consisting in determining if tags exist having one of the digits in a set corresponding to the last of said two steps.
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9. The method according to claim 8, wherein said code comprises digits to a base 10, the method comprising:
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a step for determining if tags exist having, at a digit position in their code, a digit comprised in the set {1, 2, 3, 4};
if a result of this first step is positive, a step consisting in determining if tags exist having, at a digit position in their code, one of the digits of the sets {0, 1, 2}, {3, 4};
if a result of said first step is negative, a step consisting in determining if tags exist having one of the digits of the sets {5,6}, {7, 8, 9}.
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10. The method according to claim 1, comprising, during or after step (c) a step (d) consisting in unblocking temporarily blocked tags, blocking a tag the code of which has been reconstituted, and returning to a first digit position,
and then proceeding to step (a) for identifying a next tag. -
11. The method according to claim 1, wherein step (c) additionally comprises blocking a tag the code of which has been reconstituted.
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12. The method according to claim 11, wherein said method then comprises repeating steps (a) and (c) in order to identify other tags which only differ in their last digit.
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13. The method according to claim 11, comprising the steps consisting of:
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(e) returning to a previous digit position, and unblocking those tags which were temporarily blocked at said previous digit position;
(f) determining if tags exist having one of possible digits at this digit position in their code; and
returning to step (b) if such tags exist, and otherwise, proceeding to step (c).
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14. The method according to claim 13, wherein there are a limited number of successive iterations covering steps (e) and (f) and wherein, when this limited number is reached, a step (g) is implemented consisting in unblocking tags that were temporarily blocked, and returning to a first digit position,
and then proceeding to step (a) for identifying a next tag. -
15. The method according to claim 2, wherein, when identifying a tag, said station does not again repeat polling operations for which is has received no reply from tags during preceding tag identification steps.
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16. The method according to claim 3, wherein during identification of a tag, said station does not send interrogation signals corresponding to time windows in which it received no reply from tags during preceding tag interrogation steps.
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17. Method according to claim 2, wherein during identification of a tag, said station sends successive test interrogations to said tags for the presence, at a given tag digit position, of a digit of a corresponding digit position in the code of a previously identified tag, as long as responses from tags are the same as those when a preceding tag was being identified.
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18. The method according to claim 1, further comprises a step of polling tags step of polling tags includes a step of writing into tag codes.
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19. The method according to one of claims 1 to 18, wherein polling of said tags starts at a digit position in said code which is not the first.
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20. A station for remotely identifying electronic tags each having their own code constituted by digits and an index representing a digit position in said code, comprising means for sending polling signals to said tags, means for receiving responses from said tags, and control means, wherein said polling signals comprise:
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a start-off-analysis instruction D;
an instruction A for advancing an index position in said tags;
at least one interrogation for determining whether a given digit at a digit position in said code corresponding to said index is present in said tags. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27)
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- 28. An electronic tag having means for communicating with a station for receiving polling signals from said station and for sending responses to said station, means for controlling and storing a code constituted by digits, said tag having at least one first blocked state, one second temporarily blocked state, and a third state in which it can send responses, said tag comprising an index representing a digit position within a code of said tag, and a memory for storing a digit position of said code.
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30. An electronic tag having means for communicating with a station for receiving polling signals from said station and for sending responses to said station, means for controlling and storing a code constituted by digits, said tag having at least one first blocked state, one second temporarily blocked state, and a third state in which it can send responses, said tag comprising an index representing a digit position within a code of said tag, said control means comprising means for timing responses as a function of a digit read at an address defined by said index, such that specific send time intervals correspond to various values of a digit.
Specification