On the Impact of TIG Welding Interference on Industrial Wi-Fi Networks: Modeling of Empirical Data and Analytical Studying of Coexistence

The use of IEEE 802.11 Wi-Fi in industrial applications has been enabled by time-sensitive networking (TSN) capabilities to achieve deterministic communications within time-critical applications. However, the medium access control (MAC) layer of the IEEE 802.11 still performs a carrier sense multiple access (CSMA) scheme to access the shared medium. As a result, any wireless interference over the shared medium can impact the performance of IEEE 802.11 industrial wireless networks through collisions or occupying the medium leading to increased latency and decreased service quality. By measuring the electromagnetic signal behavior of Tungsten Inert Gas (TIG) welding, we have found that it can cause interference at the 2.4 GHz band, commonly used by the IEEE 802.11 networks. In this work, we first model the measured TIG welding signal as a partitioned Markov chain, where its structure and transition probabilities are derived to accurately represent the TIG welding behavior. Then, we utilize the Markov chain model of IEEE 802.11 by Bianchi and its derivatives to predict the throughput of the IEEE 802.11 networks with TIG welding interference.