Introducing Probability in RFID Reader-to-Reader Anti-collision

Nowadays, several kinds of applications based on Radio Frequency Identification (RFID) employ a large number of tags and readers, involving collision problems. A relevant group of reader-to-reader anti-collision protocols are based on time division. Normally these protocols do not require special readers or additional entities; their main challenge is the collision resolution, since after a collision, readers have to choose a new time slot trying to avoid new collisions.It is observed that after a collision, its slot is often unoccupied, therefore this paper proposes to introduce the slot change probability as an additional parameter, in order to reduce the number of readers that change slot and the number of colliding transmissions. A new version of Distributed Color Selection (DCS) is presented, analyzed and compared with well-known protocols based on time division. The simulation analysis shows that the average time required to transmit may be reduced by over 10%.