Improving Colorwave with the probabilistic approach for reader-to-reader anti-collision TDMA protocols

In RFID systems, wireless communication among readers and tags is subject to electromagnetic interference. In particular, when several readers work closely, forming so-called Dense Reader Environment (DRE), reader-to-reader collisions may occur. Several anti-collision protocols have been proposed in the literature to address this issue. Distributed Color Selection (DCS) and Colorwave are two effective state-of-the-art protocols, based on Time Division Multiple Access (TDMA). DCS provides great fairness, but it is not adaptable to changes in network topology, penalizing the throughput of the network. Colorwave is an enhanced version of DCS offering more flexibility. Moreover, a general probabilistic approach has been suggested for solving collisions in TDMA protocols and, in particular, it has been applied to DCS. In this work, the probabilistic method is implemented in the collision resolution routine of Colorwave and its effects are analyzed, confirming the validity of this mechanism for TDMA protocols. As proved by simulation results, the probabilistic approach can be adopted to improve throughput or fairness, without adding any other requirement.