A QoS-Aware LoRa Protocol for Periodic and Aperiodic Traffic in Industrial Control Networks

Industrial control systems must support both periodic and aperiodic traffic, each with distinct timing and reliability constraints. In particular, aperiodic traffic is classified into three priority levels based on time urgency. While periodic tasks follow fixed schedules, aperiodic tasks are event-driven and require either deadline-aware access or low latency. To address these heterogeneous quality of service (QoS) requirements in duty-cycled, bandwidth-constrained long range (LoRa) networks, we propose QoS-LoRa, a deterministic MAC protocol designed for mixed-criticality traffic. QoS-LoRa integrates three key mechanisms: logical frame partitioning with distributed contention slots, deadline-aware contention window scheduling, and delay-slot-based prioritized access. Together, these components ensure low collision probability, bounded delay, and priority-respecting access across different class tasks. Simulation results show that QoS-LoRa achieves over 95% packet delivery ratio (PDR) for deadline-constrained traffic and over 92% for best-effort traffic, even under 60% aperiodic load. QoS-LoRa significantly outperforms RT-LoRa-LFP and ALOHA-based baselines in PDR, while maintaining end-to-end delay comparable to RT-LoRa-LFP, validating its effectiveness in industrial environments.