A novel tag collection algorithm using an identified slot scan for active RFID systems

We propose a novel tag collection algorithm to improve tag collection performance in active RFID systems. In the proposed algorithm, an active RFID reader differentiates identified slots from collided and empty slots via an identified-slot-scan phase, in which active RFID tags send minimal responses, and then eliminates collided and empty slots in the following tag-collection phase, in which it collects the actual data from the tags. This reduces the time wasted on collided and empty slots during tag collection, resulting in improved tag collection performance. Via simulation, we evaluated the performance improvement by the proposed algorithm for tag collection, compared to the standard tag collection algorithm. The simulation results showed that, for a set of 500 tags, the proposed algorithm reduced the average tag collection time by 36.9%, and decreased the data transmitted from the reader and the tags by 51.3% and 49.5%, respectively.