RFID (radio-frequency identification) identifies things, animals or people via electromagnetic waves. The Systems is used to automatically identify and localize participants. A RFID system always constits of two different components: the responer, and the receiver. The responder is carried by the subject to be identified and contains the necesary information. Basing on the technology the receiver either consists of a reading- or writing facility or a combination of both of them. It is mostly connected to a superior IT-system.

Finkenzeller, Klaus. RFID Handbook: Fundamentals and Applications in Contactless Smart Cards and Identification. Chichester, England: Wiley, 2003. Print.