I. Introduction
Radio Frequency Identification (RFID) is a wireless Automatic Identification and Data Capture (AIDC) technology that uses radio signals to identify object without physical contact [1], [2], [3]. In a general way, an RFID system contains three main components: tags, readers and a back-end sever. The tag is an identification device which is attached to the item. The reader is a device that can communicate with tags by radio frequency (RF). When a reader broadcasts an RF signal, the tags which are within the range of the signal will respond to the reader. Then, the reader forwards received responses to the back-end server. The back-end server who keeps a database of tags can find out detailed information associated with the tags or the items from the response messages [2]. In simple terms, the basic principle of the RFID system is that the reader uses tag's special information as a look-up key into a bank-end server to find more detailed information regarding the tag or the item [4].