System and method for identifying a radio frequency identification (RFID) device
First Claim
1. A method, comprising:
- controlling an interrogator using an application program on a host computer to receive data from the interrogator;
transmitting, from the interrogator of a plurality of interrogators, a forward link signal to implement an arbitration scheme to determine an identification code of a radio frequency identification (RFID) tag from among a plurality of RFID tags contained within an RF field of the interrogator, the forward link signal comprising a first parameter to differentiate the interrogator from a different interrogator, a second parameter to select a group of RFID tags from the plurality of RFID tags, and return link configuration information;
processing, via the RFID tag attached to an item of inventory and storing the identification code to track the item via the host computer, at least a portion of the forward link signal to differentiate the interrogator from a different interrogator using the first parameter and to compare the second parameter to a value stored in the RFID tag to determine if the RFID tag is a member of the group; and
transmitting, from the tag, a return link signal modulated in accordance with a modulation scheme selected by the return link configuration information, wherein each bit of the return link signal is multiplied by a selectable one of at least three subcarrier sequences selected by the return link configuration information.
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0 Petitions
Accused Products
Abstract
To identify an RFID tag in a field of RFID tags, an interrogator sends a series of commands to implement an arbitration scheme. The commands include differentiation, selection, and modulation information. The tag uses the differentiation information to differentiate commands sent by the interrogator from commands sent by other interrogators that may be within communication range of the tag. The selection information is used by the tag to determine if the tag is a member of a group selected by the interrogator for response to the interrogator. If the tag is a member of the selected group, the tag may send a reply that is modulated using a modulation type selected by the modulation information. In accordance with one of the modulation types, one of three different pulse waveforms is selected by the interrogator via the modulation information to multiply with the baseband waveform of the reply from the tag.
267 Citations
53 Claims
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1. A method, comprising:
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controlling an interrogator using an application program on a host computer to receive data from the interrogator; transmitting, from the interrogator of a plurality of interrogators, a forward link signal to implement an arbitration scheme to determine an identification code of a radio frequency identification (RFID) tag from among a plurality of RFID tags contained within an RF field of the interrogator, the forward link signal comprising a first parameter to differentiate the interrogator from a different interrogator, a second parameter to select a group of RFID tags from the plurality of RFID tags, and return link configuration information; processing, via the RFID tag attached to an item of inventory and storing the identification code to track the item via the host computer, at least a portion of the forward link signal to differentiate the interrogator from a different interrogator using the first parameter and to compare the second parameter to a value stored in the RFID tag to determine if the RFID tag is a member of the group; and transmitting, from the tag, a return link signal modulated in accordance with a modulation scheme selected by the return link configuration information, wherein each bit of the return link signal is multiplied by a selectable one of at least three subcarrier sequences selected by the return link configuration information. - View Dependent Claims (2, 3, 4, 5)
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6. A method, comprising:
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transmitting an interrogation signal from an interrogator of a plurality of interrogators to a radio frequency identification (RFID) tag of a plurality of RFID tags within a communication range of the interrogator, the interrogation signal comprising a first parameter to distinguish the interrogator from another interrogator of the plurality of interrogators, a second parameter to select a group of RFID tags from the plurality of RFID tags, and return link configuration information; and receiving a reply signal from the RFID tag if the RFID tag determines that the RFID tag is a member of the group based on comparing the second parameter to a value stored in the RFID tag, the reply signal being in accordance with one of a plurality of modulation types selected using the return link configuration information, wherein in accordance with one of the plurality of modulation types the return link configuration information is used to select one of at least three different pulse waveforms to multiply with a baseband waveform. - View Dependent Claims (7, 8, 9, 10, 11)
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12. A method, comprising:
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receiving an interrogation signal from an interrogator of a plurality of interrogators, the interrogation signal comprising a first parameter to distinguish the interrogator from another interrogator of the plurality of interrogators, a second parameter to select a group of radio frequency identification (RFID) tags from a plurality of RFID tags within a communication range of the interrogator, and return link configuration information; storing the first parameter in an RFID tag for use in subsequent comparisons; comparing the second parameter to a value stored in the RFID tag to determine if the RFID tag is a member of the group; and transmitting a reply signal from the RFID tag in accordance with one of a plurality of modulation types selected using the return link configuration information, wherein in accordance with one of the plurality of modulation types the return link configuration information is used to select one of at least three different pulse waveforms to multiply with a baseband waveform. - View Dependent Claims (13, 14, 15, 16)
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17. A radio frequency identification (RFID) system, comprising:
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a host computer coupled to an interrogator; a plurality of interrogators, including the interrogator coupled to the host computer, wherein the interrogator is configured to transmit commands to implement an arbitration scheme to determine an identification code of an RFID tag from among a plurality of RFID tags contained within an RF field of the interrogator, the commands comprising differentiation information, selection information, and modulation information; an item of inventory; and the RFID tag attached to the item and storing the identification code to track the item via the host computer, the tag configured to use the differentiation information to differentiate the commands from the interrogator from commands from a different interrogator, to use the selection information to determine if the RFID tag is a member of a group of tags selected by the interrogator, and to communicate a reply modulated using a modulation type selected from a plurality of modulation types by the modulation information, wherein in accordance with one of the plurality of modulation types each bit of the reply is multiplied by a selectable one of at least three subcarrier sequences selected by the modulation information. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A system, comprising:
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an interrogator configured to transmit an interrogation signal to implement an arbitration scheme to determine an identification code of a radio frequency identification (RFID) tag of a plurality of RFID tags disposed within an RF field of the interrogator, the interrogation signal comprising differentiation information, selection information, and modulation information, the differentiation information to distinguish the interrogator from a different interrogator; an item to be tracked; the RFID tag attached to the item, the tag configured to store the differentiation information, determine if the RFID tag is selected using the selection information, and communicate a reply signal having a baseband waveform multiplied by a pulse waveform selected by the modulation information from at least three different pulse waveforms; and a host computer coupled to the interrogator to receive and process the identification code. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34)
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35. A radio frequency identification (RFID) system, comprising:
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a first interrogator configured to transmit a first interrogation signal to perform collision arbitration, the first interrogation signal comprising differentiation information, selection information, and modulation information; a second interrogator configured to transmit a second interrogation signal to perform collision arbitration; a plurality of items; and a plurality of RFID tags affixed respectively to the plurality of items, each of the RFID tags configured to determine whether being selected by the selection information, use the differentiation information to distinguish the first interrogation signal transmitted by the first interrogator from the second interrogation signal transmitted by the second interrogator, and when selected, communicate a reply signal having a bit represented by a waveform sequence length selected by the modulation information from at least three different waveform sequence lengths. - View Dependent Claims (36, 37, 38, 39, 40, 41, 42, 43)
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44. A system, comprising:
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a first interrogator configured to transmit a first interrogation signal to implement arbitration; a second interrogator configured to transmit a second interrogation signal to implement arbitration, the second interrogation signal comprising differentiation information to distinguish the second interrogation signal from the first interrogation signal, selection information, and modulation information; a host computer coupled to the first and second interrogators to track a plurality of items; and a plurality of radio frequency identification (RFID) tags attached to the plurality of items respectively, the plurality of RFID tags including an RFID tag attached to an item of the plurality of items, the tag storing an identification code associated with the item, the tag configured to communicate a reply signal to the second interrogation signal if, at least in part, the tag determines that the tag is selected by the selection information, wherein the reply signal includes at least a bit represented by a waveform sequence selected by the modulation information from at least three waveform sequences of different lengths. - View Dependent Claims (45, 46, 47, 48, 49, 50, 51, 52, 53)
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Specification