Framed ALOHA for multiple RFID objects identification

Radio frequency identification (RFID) enables everyday objects to be identified, tracked, and recorded. The RFID tags are must be extremely simple and of low cost to be suitable for large scale application. An efficient RFID anti-collision mechanism must have low access latency and low power consumption. This paper investigates how to recognize multiple RFID tags within the reader's interrogation ranges without knowing the number of tags in advance by using framed ALOHA. To optimize power consumption and overall tag read time, a combinatory model was proposed to analyze both passive and active tags with consideration on capture effect over wireless fading channels. By using the model, the parameters on tag set estimation and frame size update were presented. Simulations were conducted to verify the analysis. In addition, we come up with a proposal to combat capture effect in deterministic anti-collision algorithms.