Passive RFID systems typically utilize contention-based MAC protocols, such as the standard C1G2 protocol. While these protocols are easy to implement, they suffer from unfairness and low throughput. This paper proposes a token-based MAC protocol called Token-MAC for passive RFID systems. Token-MAC is designed to enable fair access to the medium for all tags without requiring a-priori knowledge of the tags or synchronization of the tags. We implement Token-MAC as well as a TDMA-based protocol and compare these approaches with the standard C1G2 protocol. Our experiments show that Token-MAC has a higher tag rate and better fairness than C1G2, and can achieve good performance over a longer range than the TDMA-based protocol. Token-MAC is therefore a viable solution for many passive RFID systems.

Peer Reviewed