A Dynamic Rate Selection Algorithm for IEEE 802.11 Industrial Wireless LAN

The multirate support feature has been introduced by the IEEE 802.11 standard to improve the system performance, and has been widely exploited by means of rate adaptation (RA) strategies within general purpose wireless LANs. These strategies revealed ineffective for real-time industrial communications, and alternative solutions, better tailored for such a specific field of application, were investigated. The preliminary outcomes of the analyses carried out were promising, even if they clearly indicated that further efforts were necessary. In this direction, this paper first proposes rate selection for industrial networks (RSIN), an innovative RA algorithm specifically conceived for the real-time industrial scenario with the goal of minimizing the transmission error probability, while taking into account the deadline imposed to packet delivery. Then, it describes the practical implementation of RSIN on commercial devices, along with that of other formerly introduced RA techniques. Finally, the paper presents a thorough performance analysis, carried out to investigate the behavior of the addressed RA schemes. Such an assessment was performed via both experimental campaigns and simulations. The obtained results, on one hand, confirm the effectiveness of the RA techniques purposely designed for real-time industrial communication. On the other hand, they clearly indicate that RSIN outperforms all the other strategies.