System and method for electronic inventory
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Accused Products
Abstract
A system and method for conducting an inventory of tags, wherein each tag is assigned a Tag ID and a manufacturer number. Each tag can be attached to an item to take inventory of those items. A tag reader transmits a wake-up signal followed by at least one clock signal. Each tag increments a first tag count in response to the clock signals, and transmits the Tag ID assigned to the tag when the first tag count corresponds to the Tag ID assigned to the tag. The tag reader records the transmitted Tag IDs. When more than one tag transmits simultaneously, the tag stores the Tag ID in order to resolve the contention when the first read cycle is complete. In the second read cycle, the tag reader transmits the contended Tag ID followed by at least one clock signal. Each tag that contended for the transmitted Tag ID increments a second tag count in response to the clock signals, and transmits the manufacturer number assigned to the tag when the second tag count corresponds to the manufacturer number assigned to the tag. The tag reader records the transmitted Tag IDs, completing the inventory of the tags.
68 Citations
132 Claims
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1-91. -91. (canceled)
- 92. An inventory system, comprising a plurality of radio frequency identification (RFID) tags and a tag reader, wherein at least one RFID tag responds to said tag reader during one of a plurality of time slots, and said tag reader performs multiple reads of said RFID tags to avoid contention when two or more RFID tags respond during the same time slot, wherein said RFID tag is identified by a plurality of bits, wherein said RFID tag responds to said tag reader with a first plurality of said plurality of bits during a first read and a second plurality of said plurality of bits during a second read.
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113. A radio frequency identification (RFID) tag that is interrogated by a tag reader, comprising:
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means for receiving a first signal from the tag reader, the tag reader performs multiple reads of the RFID tag to avoid time slot contention, wherein the tag is identified by a plurality of bits, and wherein the tag responds to the tag reader during one of a plurality of time slots; and
means for transmitting a second signal to the tag reader in response to receiving said first signal from the tag reader, wherein said second signal includes a first plurality of said plurality of bits during a first read and a second plurality of said plurality of bits during a second read from the tag reader. - View Dependent Claims (114, 115, 116, 117, 118, 119, 120)
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121. A method for conducting an electronic inventory of radio frequency identification tags, the method comprising the steps of:
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(A) transmitting a first signal to a plurality of radio frequency identification (RFID) tags, wherein each said tag is identified by a plurality of bits, wherein said RFID tags are configured to receive and transmit signals;
(B) receiving a reply from said plurality of RFID tags during one of a plurality of time slots, said tags responding to said first signal based on the value of a first plurality of said plurality of bits; and
(C) resolving contention between multiple RFID tags if at least two of said RFID tags respond during the same time slot to said first signal, including transmitting a second signal to said plurality of RFID tags. - View Dependent Claims (122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132)
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Specification