Probabilistic Model Checking for Unconfirmed Transmission in LoRaWAN on the MAC Layer

LoRaWAN is a network technology that provides a long-range wireless network at low energy consumption. In order to save energy, it takes the pure Aloha MAC protocol and the duty-cycle limitation at both uplink and downlink on the MAC layer. Moreover, LoRaWAN also adapts the orthogonal parameters to avoid the collision. However, the star-topology synchronization and the complicated collision mechanism make quantitative model analysis difficult in LoRaWAN. This study modeled the Class-A device in the LoRaWAN protocol using Probabilistic Timed Automata (PTA). It is a mathematical model that presents the nondeterministic and probabilistic choice with time passing. Using the time representation in PTA, the transmission schedule of LoRaWAN's MAC layer of is modeled. Moreover, the full collision model is built in the PTA. Several properties are verified with the probabilistic model checker PRISM, and the quantitative properties are calculated under different cases.