Modeling and Solving the Packet Routing Problem in Industrial IoT Networks

The IEEE802.15.4-TSCH (Time Slotted Channel Hopping) is a recent Medium Accesss Control (MAC) protocol designed for Industrial Internet of Things (IIoT) applications. The data transmissions in TSCH networks are performed according to a tight schedule computed by either a centralized entity or by the network nodes. The higher the schedule length, the higher the energy consumption of the network nodes and the end-to-end delay. In this paper, we address the problem of finding optimal routing topologies that minimize the schedule length. The problem can be viewed as a particular instance of the spanning tree problem with cost associated with each arc and a proper defined function that accounts for the schedule length. We propose a formulation for the problem along with optimal solution approaches. The computational results are carried out by considering realistic instances. The aim of the experimental phase is to evaluate the influence of the problem's characteristics on the optimal solution and to assess the behavior of the proposed solution approaches.