A Fair and High Throughput Reader-to-Reader Anticollision Protocol in Dense RFID Networks

Supply chain is a typical scenario of exploiting Radio Frequency Identification (RFID) technology. Its growing use in all the supply chain areas makes the presence of many close RFID readers more common. In such environment, interferences among readers are critical. Many protocols have been proposed to reduce reader-to-reader collisions. Experimental data showed that the Neighbor Friendly Reader Anticollision (NFRA) protocol (IEEE Trans. Ind. Electron., vol. 56, no. 7, pp. 2326-2336, July 2009) maximizes the network throughput. However, it does not take into account the delay between the request and the granting of query tags, causing delays for some readers. This paper proposes two approaches to increase the fairness and ensure a high throughput for each reader. A theoretical analysis, supported by experimental simulations, demonstrates the improvements achieved.