Multi-channel Conflict-Free Scheduling Algorithm for IEEE 802.15.4e/TSCH Networks

Time slotted channel hopping (TSCH) is an emerging MAC behaviour mode defined in the IEEE 802.15.4e standard. Based on spatial reuse of time slot and channel hopping, known to deliver high network reliability, and low latency and it’s a prominent candidate to support IoT applications. However, it has only defined a minimal configuration for the scheduling mechanism where the collision risk between the nodes, that share the same time slot, is very high leading to poor performance. That is why the scheduling issue has attracted the attention of many researchers in recent time. In this paper, we propose a scheduling algorithm, called multi-channel conflict-free scheduling (MCF-TSCH), a centralized approach that considers the level of the nodes in the network, time slots spatial reuse and channel hopping. It aims to enhance TSCH by minimizing the slot frame length and building a conflict-free schedule. We programmed our algorithm in C# language for simulation and we used a hierarchical Colored Petri Nets (HCPN) to validate our proposition and show that our algorithm terminates correctly and meets some key properties. Indeed, besides the simulation results and the model correctness, the formal analysis using CPN Tools proves that the resulting schedules satisfy the defined objectives.