Real-time Cooperative Communication for Automation over Wireless

Abstract: High-performance industrial automation systems rely on tens of simultaneously active sensors and actuators and have stringent communication latency and reliability requirements. Current wireless technologies like WiFi, Bluetooth, and LTE are unable to meet these requirements, forcing the use of wired communication in industrial control systems. This paper introduces a wireless communication protocol that capitalizes on multiuser diversity and cooperative communication to achieve the ultra-reliability with a low-latency constraint. Our protocol is analyzed using the communication-theoretic delay-limited-capacity framework and compared to baseline schemes that primarily exploit frequency diversity. For a scenario inspired by an industrial printing application with thirty nodes in the control loop, 20B messages transmitted between pairs of nodes and a cycle time of $2$ ms, an idealized protocol can achieve a cycle failure probability (probability that any packet in a cycle is not successfully delivered) lower than $10^{-9}$ with nominal SNR below 5 dB in a 20MHz wide channel.