Expanding Horizon and Capture Effect in RFID Singulation

We present two singulation schemes for passive RFID systems. The first scheme, called expanding horizon, uses interrogator transmit power control to singulate tags in concentric annuli. We show through analysis that this scheme is very time-efficient and conserves energy. Our second scheme is a combination parallel interrogation and TDMA scheme that applies to multiple interrogator situations. It leverages the capture effect to singulate many tags, even when these tags may be receiving signals from multiple interrogators. This provides a time-efficient scheme, as shown in our simulations.