Run-time estimation of the number of un-identified tags in RFID systems

Performance of the dynamic framed slotted aloha (DFSA) based Radio Frequency Identification (RFID) system greatly depend on an accurate estimation of the number of unidentified tags. In this paper, we show that the number of unidentified tags can be express as a function of the collision rate experienced when a RFID reader collects tags' Unique ID (UID), and then we develop a linear interpolation algorithm to estimate the number of un-identified tags on run-time measurements. Simulation results show that our approach has high accurate rate and is adaptive to the current channel status.