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Decoding the Collisions in RFID System
MPhil Thesis Defence Title: "Decoding the Collisions in RFID System" By Mr. Lei Kang Abstract Traditionally, collision alone is nothing but noise. This paper adopts a new approach; it directly decodes the collisions without exact knowledge of collided packets. RFID tag uses random number (RN) to contend for tag identification. We re-design the RN pattern to be only one or two "1" bits in it, so that we can decode the collided RNs and know the number of them by subtracting the known symbols. Two key tasks in RFID systems, tag identification and tag number estimation, can be performed in a much more efficient way. The new scheme makes no changes to the RFID MAC and introduces no overhead when the traditional reader or tags are used. We extend the RN generator on USRP RFID tag and implement a decoding algorithm at the physical layer on USRP RFID reader to demonstrate the practicability of our design. The new approach improves the throughput by 70% in tag identification and enhances the counting efficiency by orders of magnitude compared to existing solutions. Date: Tuesday, 6 July 2010 Time: 1:30pm – 3:30pm Venue: Room 3501 Lifts 25/26 Committee Members: Prof. Lionel Ni (Supervisor) Dr. Lin Gu (Chairperson) Dr. Lei Chen **** ALL are Welcome ****