Distributed Tag Access with Collision-Avoidance among Mobile RFID Readers

Concurrent access among multiple mobile readers brings about a new problem called reader collision that a readerpsilas transmission is interfered by the others. There have been several works to solve the reader collision problem. While they employ time division, frequency division, space division, or centralized scheduling approach, in this paper, we introduce a cooperative, distributed reader collision avoidance algorithm. In particular, it is suitable for energy-efficient wireless mobile network environment cooperated with RFID, since the proposed DiCa (Distributed Tag Access with Collision-Avoidance) is capable of not only avoiding collisions but also changing power state autonomously through only distributed simple interactions between adjacent readers.