CDMA-Based UHF-RFID System With Semi-Passive UHF Transponders
RFID systems, in general, increase the efficiency of logistic systems, e.g., inventory of stocks. Unfortunately, present existing systems come fast to their limits if a certain number of RFID transponders must be inventoried in a limited period of time, as the channel access method of current RFID systems is based on Time Division Multiple Access. To shorten the inventory process, this paper shows an implementation of an UHF RFID system based on semi-passive UHF transponders, using Code Division Multiple Access as anti-collision method. This paper focuses on the uplink channel (tag to reader) that covers the transponders' backscattered signals.