TSCH based multiplex access for IoT: communications scheduling assessment in multi-path ray-tracer medium

Time Slotted Channel Hopping (TSCH) protocol, as specified in the IEEE 802.15.4 standard, is engineered to fulfill the demanding communication needs of industrial IoT networks. TSCH leverages a blend of multi-channel access techniques to effectively manage resources and orchestrate communication among devices within an IoT network. Various TSCH schedulers are available to cater to a wide range of application scenarios, providing the protocol with adaptability. This study evaluates scheduler performance under high traffic loads and a Multi-Path Ray-Tracer Medium (MRM), which is characterized by complex traffic patterns near to realistic scenario as refraction, reflection, diffraction and scattering. The evaluation encompasses several schedulers, including ALICE link-based scheduling, Minimal Scheduling, Orchestra Sender Based Shared (O-SBS), and Orchestra Receiver Based Shared (O-RBS). Key performance metrics such as Packet Delivery Ratio (PDR), Packet Acknowledgment Ratio (PAR), Radio-On duty cycle (DC), and End-to-End Latency are meticulously examined. The results highlight disparities in reliability across different schedulers, notably the reduced reliability observed with the Orchestra RBS scheduler under high traffic conditions compared to prior research. Conversely, the ALICE scheduler demonstrates enhanced reliability and network stability under varying traffic loads, accompanied by the lowest end-to-end latency in scenarios with heightened traffic volumes. Despite these findings, Minimal Scheduling maintains competitiveness against Orchestra and ALICE in scenarios characterized by low traffic loads, irrespective of the performance metrics considered. Furthermore, we propose optimizations for the Orchestra scheduler variants in terms of parameters related to TSCH and RPL configurations. These optimized schedulers show a PDR higher than 97%, as well as a decrease in energy consumption and latency time compared to ALICE.