Tag Identification Protocols in RFID Systems

Fast and reliable identification of multiple objects that are present at the same time is very important in many applications. A very promising technology for this purpose is Radio Frequency Identification (RFID), which is fast pervading many application fields, like public transportation and ticketing, access control, production control, animal identification, and localization of objects and people. The problem approached in this chapter is the tag identification in RFID systems. This problem occurs when several tags try to answer at the same time to a reader query. If more than one tag answers, their messages will collide on the RF communication channel, and the reader cannot identify these tags. There are two families of protocols for approaching the tag collision problem: a family of probabilistic protocols, and a family of deterministic ones. In this chapter, the authors give an overview of the most important approaches and trends for tag identification in RFID systems and provide the results of a deep comparison of the presented tag identification protocols in terms of complexity and performance.