Network Coding for Real-time Wireless Communication for Automation

Real-time applications require latencies on the order of a millisecond with very high reliabilities, paralleling the requirements for high-performance industrial control. Current wireless technologies like WiFi, Bluetooth, LTE, etc. are unable to meet these stringent latency and reliability requirements, forcing the use of wired systems. This paper introduces a wireless communication protocol based on network coding that in conjunction with cooperative communication techniques builds the necessary diversity to achieve the target reliability. The proposed protocol is analyzed using a communication theoretic delay-limited-capacity framework and compared to proposed protocols without network coding. The results show that for larger network sizes or payloads employing network coding lowers the minimum SNR required to achieve the target reliability. For a scenario inspired by an industrial printing application with $30$ nodes in the control loop, aggregate throughput of $4.8$ Mb/s, $20$MHz of bandwidth and cycle time under $2$ ms, the protocol can robustly achieve a system probability of error better than $10^{-9}$ with a nominal SNR less than $2$ dB under ideal channel conditions.