Comparing Theoretical and Experimental Results in Gen2 RFID Throughput
Radio frequency identification (RFID) technology, based on wireless communication between a reader and tags, is the most popular technology for indoor item identification and tracking. Among competing RFID technologies, Gen2 has emerged as the most popular one, due to the best price/performance ratio. In order to communicate with multiple tags, Gen2 RFID systems use dynamic frame slotted ALOHA (DFSA) as a medium access control (MAC) mechanism. To maximize DFSA throughput simple calculations show that the number of tags should equal the DFSA frame size. However, the number of tags in an environment is usually unknown and has to be estimated. So far, significant effort has been invested in estimating the correct number of tags. However, to the best of our knowledge, no one has explored the estimator performance in a real RFID measuring scenario. In this paper, we evaluate the throughput of a real RFID system by using the Software Defined Radio (SDR) technology. Our results show that phenomena related to radio waves propagation and reception have a significantly bigger influence on Gen2 RFID throughput than traditional approaches take into account.