Method and system of using a RFID reader network to provide a large operating area
First Claim
1. A RFID system comprising:
- a plurality of RFID readers;
network means for networking said plurality of RFID readers; and
means for avoiding interference among said plurality of RFID readers;
wherein each of said plurality of RFID readers are operated in sequence or simultaneously with other ones of said plurality of RFID readers for avoiding interference.
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Abstract
The present invention relates to a method and apparatus for using a RFID reader network to provide a large operating area, thereby enabling multiple RFID readers to simultaneously operate with minimal interference among all the RFID readers in the same network. The RFID network comprises a plurality of RFID readers connected to a server via a network backbone. Each operating RFID reader is associated with a group of neighboring RFID readers. A neighboring RFID reader is defined as a RFID reader that can detect tag responses for the communication between the operating RFID reader and its RFID tags. Each operating RFID reader sends its neighboring RFID readers at least one Tag Operation (TO) packet before starting to communicate with RFID tags and at least one End of Tag Operation (ETO) packet after the tag operation is completed. To avoid interference, each RFID reader uses a listen-before-talk scheme in which it checks if any TO packet has been sent by neighboring RFID readers before starting radio transmission. If both RFID readers are allowed to transmit, the RFID reader with a neighboring RFID reader just finishing transmission has the higher priority. This approach improves the throughput by taking advantage of the overlapped areas of neighboring RFID readers.
198 Citations
25 Claims
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1. A RFID system comprising:
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a plurality of RFID readers;
network means for networking said plurality of RFID readers; and
means for avoiding interference among said plurality of RFID readers;
wherein each of said plurality of RFID readers are operated in sequence or simultaneously with other ones of said plurality of RFID readers for avoiding interference. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of operating a RFID system comprising the steps of:
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a. establishing a network of a plurality of RFID readers;
b. forming a RFID reader group by estimating an interference level between each of said plurality of RFID readers; and
c. operating said plurality of RFID readers in sequence or simultaneously with other ones of said plurality of RFID readers based on said determined interference level. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A method for improving RFID tag detection in a RFID system comprising the steps of:
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synchronizing at least one RFID reader to a RFID transmitting reader;
simultaneously listening at each said synchronized at least one RFID reader to RFID tag responses;
forwarding said RFID tag responses to said transmitting reader; and
operating said transmitting reader based on said RFID tag responses. - View Dependent Claims (24, 25)
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Specification