Ultra-reliable and real-time communication in local wireless applications

This paper presents a wireless MAC and networking protocol called Real-time Network Protocol (RNP) for ultra-reliable and real-time communication in wireless applications using a small number of nodes. RNP is a collaborative and hybrid TDMA/CSMA MAC protocol with implicit routing, designed especially for small, fast, and time-constrained Wireless Sensor and Actuator Networks in harsh industrial environments. The design is targeted for industrial applications where reliability is the top priority and special attention is put on selection of retransmission method and cooperation between the nodes to collect data periodically. For reliability in RNP several diversity techniques using collaborative retransmission, piggybacking and spatial diversity are proposed. Using analysis, simulations, and a real deployment in an industrial setting, it is shown that RNP achieves high reliability and outperforms alternative designs.