Section: New Results

RFID

Participant : Nathalie Mitton.

One of the devices under consideration by the FUN team is RFID. One of the main issues to widely deploy RFID reader is reader-to-reader collision. Indeed, when the electromagnetic fields of the readers overlap, a collision occurs on the tag laying in the overlapping section and cannot be read. In [10] , we propose a high adaptive contention-based medium access control (HAMAC) protocol that considerably reduces readers collision problems in a large-scale dynamic RFID system. HAMAC is based only on realistic assumptions that can be experimented and does not require any additional components on RFID reader in order to improve the performance in terms of throughput, fairness and latency. The central idea of the HAMAC is for the RFID reader to use a WSN-like CSMA approach and to set its initial backoff counter to the maximum value that allows to mitigate collision. Then, according to the network congestion on physical channels the reader tries to dynamically control its contention window by linear decreasing on selected physical channel or multiplicative decreasing after scanning all available physical channels. Extensive simulations are proposed to highlight the performance of HAMAC compared to literature's work in large-scale RFID systems where both readers and tags are mobile. Simulation results show the effectiveness and robustness of the proposed anti-collision protocol in terms of network throughput, fairness, coverage and time to read all tags.