Analysis of Master-Slave protocols for real-time industrial communications over IEEE 802.11 WLANs

The recent performance improvements of wireless communication systems are making possible the use of such networks for industrial applications, which typically impose severe requirements in term of both real-time communications and dependability. Several independent studies have highlighted that the IEEE802.11 Wireless LAN is one of the most suitable products for such applications. However, since such standard is only concerned with the lower layers of the communication stack, it is necessary to integrate it with appropriate protocols, typical of the industrial communications. In this direction, the protocols used by the traditional fieldbuses could represent an interesting opportunity. In this paper we consider one of these protocols, based on a Master-Slave architecture, and analyze the possibility of implementing it on top of IEEE802.11. After a description of how the Master-Slave functions could be mapped onto the IEEE802.11 services, we develop a theoretical model of the proposed communication architecture which allows for the evaluation of some performance metrics.