A Reliability Analysis of TSCH Protocol in a Mobile Scenario

International audience; Future industrial low-power wireless networks together with cyber-physical systems demand mobile nodes to support diverse applications so as to increase operational efficiency and ensure autonomy. Mobility induces several challenges for low-power lossy networks due to dynamic topology, RF link instability, synchronization loss, signaling overhead, which lead to significant packet loss, more energy consumption, and higher latency. In this paper, we study a widely adopted time-slotted channel hopping (TSCH) MAC protocol in the presence of mobile nodes. We analyze how mobility impacts its reliability in terms of synchronization, message overhead, latency, and energy. The evaluation is performed through simulation and the results show that mobility may cause significant network downtime where nodes are unable to associate to the network for long period of time because of synchronization loss, especially if the environment is not fully covered by static nodes. Association and disassociation issues, induced by mobility, cause frequent disruptions in the network. Although, TSCH can handle mobility if the network space in which mobile nodes are evolving is fully covered by static nodes or there are enough mobile nodes to maintain a consistent coverage. However, the amount of message overhead to maintain synchronization is higher which impacts the reliability of the protocol in terms of energy and latency.