SYSTEMS AND METHODS FOR SYNCHRONIZING A PLURALITY OF RFID INTERROGATORS IN A THEATRE OF OPERATION
First Claim
1. A radio frequency identification (RFID) interrogation system, comprising:
- multiple RFID interrogators, wherein each of the multiple RFID interrogators is configured to transmit a plurality of synchronization pulses to surrounding RFID tags, and wherein the multiple RFID interrogators includes a first RFID interrogator, which is configured to;
transmit a synchronization pulse to nearby RFID tags;
while listening for RFID tag transmissions in response to the synchronization pulse, attempt to detect any interference from another RFID interrogator among the multiple RFID interrogators; and
if an interference is detected from a second RFID interrogator among the multiple RFID interrogators, determine if data is expected from a nearby RFID tag, andif no data is expected, synchronize a transmission of the next synchronization pulse with the next synchronization pulse of the second RFID interrogator;
otherwise, wait for the expected data from the nearby RFID tag.
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Accused Products
Abstract
RFID tags are used for many purpose including tracking. RFID interrogators are used to retrieve information from tags. In many applications, a plurality of RFID interrogators are required. Synchronization between interrogators in the same theatre of operation is critical to ensure that their broadcasts do not interfere with each other. In fixed RFID interrogator applications, RFID interrogators can be wired together allowing a channel to synchronize the transmissions of the RFID interrogators. Methods described herein can ensure that synchronization is maintained in the event of the failure of a synchronizing master. Furthermore, additional methods for synchronizing RFID interrogators in wireless applications are described allowing synchronization in the absence of wired connections between interrogators.
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Citations
20 Claims
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1. A radio frequency identification (RFID) interrogation system, comprising:
multiple RFID interrogators, wherein each of the multiple RFID interrogators is configured to transmit a plurality of synchronization pulses to surrounding RFID tags, and wherein the multiple RFID interrogators includes a first RFID interrogator, which is configured to; transmit a synchronization pulse to nearby RFID tags; while listening for RFID tag transmissions in response to the synchronization pulse, attempt to detect any interference from another RFID interrogator among the multiple RFID interrogators; and if an interference is detected from a second RFID interrogator among the multiple RFID interrogators, determine if data is expected from a nearby RFID tag, and if no data is expected, synchronize a transmission of the next synchronization pulse with the next synchronization pulse of the second RFID interrogator; otherwise, wait for the expected data from the nearby RFID tag. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for operating a first radio frequency identification (RFID) interrogator among multiple RFID interrogators while avoiding interferences with other RFID interrogators among the multiple RFID interrogators, comprising:
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transmitting a synchronization pulse by the first RFID interrogator to surrounding RFID tags; while listening for RFID tag transmissions in response to the synchronization pulse, attempting to detect any interference from another RFID interrogator among the multiple RFID interrogators; if an interference is detected from a second RFID interrogator among the multiple RFID interrogators, determining if data is expected from a nearby RFID tag, and if no data is expected, synchronizing a transmission of the next synchronization pulse of the first RFID interrogator with the next synchronization pulse of the second RFID interrogator; otherwise, waiting for the expected data from the nearby RFID tag. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification