Method and system for distance determination of rf tags
First Claim
Patent Images
1. A method for communicating between a reader and a plurality of RF tags, comprising the steps of:
- (a) transmitting a wide band broadcast interrogation signal by a reader, (b) at least one tag is waiting to receive said wide band broadcast interrogation signal, (c) at least one of said at least one tag waiting to receive said wide band broadcast interrogation signal is receiving said wide band broadcast interrogation signal and transmitting at least one wide band response signal, (d) receiving at least one wide band response signal by said reader, wherein said at least one wide band response signal received by said reader may include overlapping wide band response signals whenever it is comprising of a plurality of wide band response signals transmitted by a plurality of said tags, and (i) detecting by said reader the distinguishable response sequences, transmitted by said tags, included in said at least one wide band response signal received by said reader, (ii) estimating by said reader the number of wide band response signals to said wide band broadcast interrogation signal, (iii) analyzing by said reader said distinguishable wide band response signals in order to determine their round trip delay, (e) Testing by said reader a predefined statistical criterion indicative of the collision probability of said at least one wide band response signal and according to the result of said test there is transmitting by said reader at least one additional wide band broadcast interrogation signal, whereby each said additional wide band broadcast interrogation signal is followed by repeating the steps of said at least one tag answering and said reader receiving, detecting, estimating, analyzing, testing and transmitting by said reader at least one additional wide band broadcast interrogation signal.
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Abstract
The present invention relates to a method and system (10) for distance determination of RF tags (4) and its applications based on measuring the round trip delay, avoiding deterministic collisions between a plurality of wide band response signals transmitted by the tags (4) by adding a pseudo-random time delay to the wide band response signal, and iteratively reducing the collision probability between plurality of wide band response signals.
115 Citations
125 Claims
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1. A method for communicating between a reader and a plurality of RF tags, comprising the steps of:
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(a) transmitting a wide band broadcast interrogation signal by a reader, (b) at least one tag is waiting to receive said wide band broadcast interrogation signal, (c) at least one of said at least one tag waiting to receive said wide band broadcast interrogation signal is receiving said wide band broadcast interrogation signal and transmitting at least one wide band response signal, (d) receiving at least one wide band response signal by said reader, wherein said at least one wide band response signal received by said reader may include overlapping wide band response signals whenever it is comprising of a plurality of wide band response signals transmitted by a plurality of said tags, and (i) detecting by said reader the distinguishable response sequences, transmitted by said tags, included in said at least one wide band response signal received by said reader, (ii) estimating by said reader the number of wide band response signals to said wide band broadcast interrogation signal, (iii) analyzing by said reader said distinguishable wide band response signals in order to determine their round trip delay, (e) Testing by said reader a predefined statistical criterion indicative of the collision probability of said at least one wide band response signal and according to the result of said test there is transmitting by said reader at least one additional wide band broadcast interrogation signal, whereby each said additional wide band broadcast interrogation signal is followed by repeating the steps of said at least one tag answering and said reader receiving, detecting, estimating, analyzing, testing and transmitting by said reader at least one additional wide band broadcast interrogation signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 120)
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44. A system for communicating between a reader and a plurality of RF tags, comprising:
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(a) a reader, for transmitting a wide band broadcast interrogation signal, (b) at least one tag, for waiting to receive said wide band broadcast interrogation signal, (c) at least one of said at least one tag waiting to receive said wide band broadcast interrogation signal is receiving said wide band broadcast interrogation signal and transmitting at least one wide band response signal, (d) said reader is receiving at least one wide band response signal, wherein said at least one wide band response signal received by said reader may include overlapping wide band response signals whenever it is comprising of a plurality of wide band response signals transmitted by a plurality of said tags, and (i) said reader is detecting the distinguishable response sequence, transmitted by said tags, included in said at least one wide band response signal received by said reader, (ii) said reader is estimating the number of wide band response signals to said wide band broadcast interrogation signal, (iii) said reader is analyzing said distinguishable wide band response signals in order to determine their round trip delay, (e) said reader is testing a predefined statistical criterion indicative of the collision probability of said at least one wide band response signal and according to the result of said test there is transmitting by said reader at least one additional wide band broadcast interrogation signal, whereby each said additional wide band broadcast interrogation signal is followed by repeating the steps of said at least one tag answering and said reader receiving, detecting, estimating, analyzing, testing and transmitting by said reader at least one additional wide band broadcast interrogation signal. - View Dependent Claims (45)
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46. A method for defining a programmable reader cell in RFID system, comprising the steps of:
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(a) transmitting a wide band broadcast interrogation signal, by a reader, (b) at least one tag is waiting to receive said wide band broadcast interrogation signal, (c) at least one of said at least one tag waiting to receive said wide band broadcast interrogation signal is receiving said wide band broadcast interrogation signal and transmitting at least one wide band response signal, (d) receiving by said reader at least one wide band response signal, wherein said at least one wide band response signal received by said reader may include overlapping wide band response signals whenever it is comprising of a plurality of wide band response signals transmitted by a plurality of said tags, (e) detecting by said reader at least one response sequence included in said at least one wide band response signal received by said reader, and deciding whether one or more tags answered to said wide band broadcast interrogation signal, (f) analyzing by said reader the at least one detected wide band response signal, in order to determine the round trip delay of at least one of said at least one wide band response signal received by said reader, (g) said reader comparing a predefined threshold to said round trip delay of at least one of said at least one wide band response signal received by said reader, and performing a task with tags having round trip delay that is passing said predefined threshold test. - View Dependent Claims (47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83)
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84. A system for defining a programmable reader cell in RFID system, comprising:
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(a) a reader, for transmitting a wide band broadcast interrogation signal, (b) at least one tag, for waiting to receive said wide band broadcast interrogation signal, (c) at least one of said at least one tag waiting to receive said wide band broadcast interrogation signal is receiving said wide band broadcast interrogation signal and transmitting at least one wide band response signal, (d) said reader is receiving at least one wide band response signal, wherein said at least one wide band response signal received by said reader may include overlapping wide band response signals whenever it is comprising of a plurality of wide band response signals transmitted by a plurality of said tags, (e) said reader detecting at least one response sequence included in said at least one wide band response signal received by said reader, and deciding whether one or more tags answered to said wide band broadcast interrogation signal, (f) said reader analyzing the at least one detected wide band response signal, in order to determine the round trip delay of at least one of said at least one wide band response signal received by said reader, (g) said reader comparing a predefined threshold to said round trip delay of at least one of said at least one wide band response signal received by said reader, and performing a task with tags having round trip delay that is passing said predefined threshold test.
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85. A method for locating the position of at least one RF tag in relation to the position of at least two readers, comprising the steps of:
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(a) transmitting a wide band broadcast interrogation signal, by each of said at least two readers, (b) at least one tag is waiting to receive said wide band broadcast interrogation signals, (c) transmitting a wide band response signal, by said at least one tag, to each one of said received wide band broadcast interrogation signals, wherein each one of said wide band response signals includes identification information about the interrogating reader and about said transmitting tag, (d) receiving, by each one of said at least two readers, at least one of said wide band response signals, wherein said at least one wide band response signal received by said readers may include overlapping wide band response signals whenever it is comprising of a plurality of wide band response signals transmitted by a plurality of said tags, (e) detecting, by each one of said at least two readers, said at least one wide band response signal, deciding whether one or more tags answered to its wide band broadcast interrogation signal, and analyzing said at least one wide band response signal, transmitted by a tag, in order to determine the round trip delay and identification information, (f) transferring, from each one of said at least two readers, distance and identity information of said tags and said reader itself to a central processing unit, (g) by using the information transferred from said each one of said at least two readers, locating the position of said at least one tag in relation to the position of said at least two readers, by said central processing unit. - View Dependent Claims (86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 121, 122, 123, 124)
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125. A system for locating the position of at least one RF tag in relation to the position of at least two readers, comprising:
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(a) each of said at least two readers is transmitting a wide band broadcast interrogation signal, (b) at least one tag is waiting to receive said wide band broadcast interrogation signals, (c) said at least one tag is transmitting a wide band response signal to each one of said wide band broadcast interrogation signals it received, wherein each one of said wide band response signals includes identification information about the interrogating reader and about said transmitting tag, (d) each one of said at least two readers is receiving at least one of said wide band response signals, wherein said at least one wide band response signal received by said readers may include overlapping wide band response signals whenever it is comprising of a plurality of wide band response signals transmitted by a plurality of said tags, (e) each of said at least two readers is detecting said at least one wide band response signal, deciding whether one or more tags answered to its wide band broadcast interrogation signal, and analyzing said at least one wide band response signal, transmitted by a tag, in order to determine the round trip delay and identification information, (f) each one of said at least two readers is transferring distance and identity information of said tags and said reader itself to a central processing unit, (g) by using the information transferred from said each one of said at least two readers, said central processing unit is locating the position of said at least one tag in relation to the position of said at least two readers.
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Specification