Fast and Reliable Estimation Schemes in RFID Systems

RFID tags are being used in many diverse applications in increasingly large numbers. These capabilities of these tags span from very dumb passive tags to smart active tags, with the cost of these tags correspondingly ranging from a few pennies to many dollars. One of the common problems that arise in any RFID deployment is the problem of quick estimation of the number of tags in the field up to a desired level of accuracy. Prior work in this area has focused on the identification of tags, which needs more time, and is unsuitable for many situations, especially where the tag set is dense or highly dynamic. We take a different, more practical approach, and provide very fast and reliable estimation mechanisms. In particular, we analyze our estimation schemes and show that the time needed to estimate the number of tags in the system for a given accuracy is much better than schemes presented in related work. We also show how the estimation schemes can be used reliably in highly dynamic environments where the tag set can change rapidly.