A hybrid randomized protocol for RFID tag identification

Purpose – Radio frequency identification (RFID) is a technology for tracking objects that is expected to be widely adopted in very near future. A reader device sends probes to a set of RFID tags, which then respond to the request. A tag is recognized only when it is the only one to respond to the probe. Only reader has collision detection capability. The problem considered here is to minimize the number of probes necessary for reading all the tags, assuming that the number of tags is known in advance. Design/methodology/approach – Well known binary and n-ary partitioning algorithms can be applied to solve the problem for the case of known number of tags. A new randomized hybrid tag identification protocol has been proposed, which combines the two partitioning algorithms into a more efficient one. The new scheme optimizes the binary partition protocol for small values of n (e.g. n 1⁄4 2, 3, 4). The hybrid scheme then applies n-ary partition protocol on the whole set, followed by binary partition on the tags that caused collision. Findings – It is analytically proved that the expected number of time slots in the hybrid algorithm with known number of users is less than 2.20 n. Performance of these algorithms was also evaluated experimentally, and an improvement from en to approximately 2.15 n was obtained. Originality/value – The algorithm shown here is efficient both by theory and practice and outperforms existing ones.