PLAT: A physical-layer tag searching protocol in large RFID systems

Radio Frequency Identification (RFID) technology brings a revolutionary change in warehouse management by automatically monitoring and tracking products. For many RFID-enabled applications, fast searching a particular group of products is practically important in a large-scale RFID system. Different from previous searching protocols, we propose a physical layer tag searching (PLAT) protocol, which makes three fundamental improvements. First, PLAT can exactly pinpoint the search result without false positives at a small delay expense. Second, based on the physical layer signals, PLAT can interpret the accurate number of tags replying in a collision slot, speeding up the execution of tag searching. Third, PLAT can take the global view of the accurate replying information from slots to extract each tag identifier, further improving the protocol performance. We also implement a prototype system based on the USRP and WISP platform. Experimental results validate the feasibility of our protocol. The extensive simulations show PLAT produces the performance gain by a factor of above 2 compared with the state-of-the-art works.