Optimal routing approaches for IEEE 802.15.4 TSCH networks

The IEEE 802.15.4 time-slotted channel hopping (TSCH) is a medium access control layer protocol designed for industrial internet of things applications. The TSCH focuses on the media access control layer only, while the construction of the routes relies on network layer protocols such as the routing protocol for low-power and lossy networks. The selection of the routes toward the sink plays a significant role in the nodes duty cycle, the delay, and the reliability of the network. In this paper, we formulate a multiobjective problem taking into account the schedule length (duty cycle/delay), the average number of hops (delay), and the cost of constructing the routes (reliability). To solve this problem, we use a scalarizing version where the objective function is defined as a convex combination of the three aforementioned parameters. Optimal computational as well as simulation results are presented. The findings of the current study can be used either as an optimal static routing solution when the link qualities are known and do not considerably change through time, or as a benchmark when designing low-power distributed protocols for TSCH networks.