Evaluation of Throughput of TDMA Anti-Collision Protocols in Static and Mobile RFID Networks

In an RFID network, readers simultaneously querying tags may interfere with each other, generating a reader collision that prevents the tag identification. The reader-to-reader interference can occur among readers closer than a given distance, called interference range. Readers within the interference range are called neighbors. Many protocols designed to tackle reader collisions are based on a TDMA scheme. The performance of an anti-collision protocol can be measured in terms of throughput, i.e., the number of times readers can successfully query tags. This paper quantifies the size of the neighborhood and then analyzes its impact on the throughput of TDMA anti-collision protocols. The average number of neighbors is shown to depend not only on the number of readers in the RFID network, but also on the mobility of the readers. Thus, both static and mobile RFID systems are investigated. By simulating two state-of-the-art protocols, it is shown how properly setting the configuration parameters of the TDMA protocols according to the average amount of the neighborhood in order to achieve the highest throughput.