Efficient Localization based on Imprecise Anchors in RFID System Motivation Challenges The anchor positions are imprecise. Items of the same category can be placed in a range rather than on a precise point on the shelf. The reader may miss some of the nearby RFID tags due to imperfect radio environments. Time efficiency is required. RFID readers takes more time to scan nearby RFID tags when the density of RFID is increased. Return useful information in a timely manner even if the reader is surrounded by thousands of RFID tags. Xiang Lu,Lei Xie,Yafeng Yin,Wei Wang,Baoliu Ye,Sanglu Lu State Key Laboratory for Novel Software Technology,Nanjing University,ChinaMotivation Xiang Lu, Lei Xie, Yafeng Yin, Wei Wang, Baoliu Ye, Sanglu Lu State Key Laboratory for Novel Software Technology, Nanjing University, China Efficient Localization based on Imprecise Anchors in RFID System  Challenges  The anchor positions are imprecise.  Items of the same category can be placed in a range rather than on a precise point on the shelf.  The reader may miss some of the nearby RFID tags due to imperfect radio environments.  Time efficiency is required.  RFID readers takes more time to scan nearby RFID tags when the density of RFID is increased.  Return useful information in a timely manner even if the reader is surrounded by thousands of RFID tags