A Multiple RFID Readers Anti-collision Algorithm for RFID Tags Identification based on Graph Theory

In a large-scale multiple RFID readers system, the signal between the readers will interfere with each other during the tags identification, which is called reader collision. Such that, this paper proposes a Multiple RFID Readers Anti-collision Algorithm for RFID Tags Identification based on Graph Theory (MRGT) to deal with the interference. The algorithm establishes an interference graph for the RFID readers network used to select the independent set of the RFID readers and avoid the collision among multiple readers by arranging different communication slots and frequencies for different reader sets. Simulation results show that the proposed algorithm increases the number of active readers per second by 6.4% and 11.56% respectively on average, and the tag recognition rate is also increased by 6 and 11 times respectively compared with the classic algorithm Neighbor Friendly Reader Anti-Collision Protocol (NFRA) and distributed color selection (DCS) algorithm, and so the system efficiency and tag recognition rate of MRGT are better than that of NFRA and DCS.