Estimation Algorithm of Identifying Object Number in Passive RFID System

This paper investigates how to shorten identifying time of multiple objects and gain maximum throughput between reader and tags in passive RFID system. We present a combinatorial model of the communication mechanism between reader and tags, and use this model to deduce an algorithm to estimate tag number: BDE (binomial distributing estimation) algorithm. With the help of BDE algorithm, we then select optimal slot number in slotted ALOHA protocol. Simulation results are the following: first, identifying time of BDE algorithm is satisfyingly shortened when identifying tag number is one, two and three, and then it increases linearly with tag number. Second, throughput is about 34%, which is closed to academic maximum. Third, Analysis of identifying time ingredients indicates that to optimize reader commands and speed up reader data rate can shorten identifying time further.