A new medium access protocol for RFID networks with foresight

In the world where automating jobs is becoming a norm it is no surprise that the interest in RFID networks has grown exponentially. With RFID technology companies around the world can reduce their workforce and grow their business. However, this technology is not at that maturity point yet. In order for a cart full of groceries to go through an unmanned checkout lane, it is crucial that all of the tagged items are read and processed with 100% reliability. Also the process time needs to be short so that customers complete their purchases as fast as possible. In order to achieve time and reliability, several transmission control protocols have been devised. Out of these, the transmission control protocol that is most popular with RFID equipment manufacturers is EPCglobal´s Class 1 Gen2. The transmission control in EPC C1G2 is achieved by framed slotted ALOHA where tags pick a random slot from the choices given by the reader and when their turn comes, they backscatter their information. This can lead to many empty slots and many collision slots apart from the successful slot. The time spent on these non-successful slots is studied in [4] and in this paper we extended the concept provided in [4] and propose a new method that scans for the empty and collided slots before attempting to read tags.