Energy Efficiency of Slotted LoRaWAN Communication With Out-of-Band Synchronization

Although the idea of using wireless links for covering large areas is not new, advent LPWANs has recently started changing game. Simple, robust, narrowband modulation schemes permit implementation low-cost radio devices offering high receiver sensitivity, thus improving overall link budget. The several technologies belonging to LPWAN family, including well-known LoRaWAN solution, provide a cost-effective answer many Internet-of-things (IoT) applications, requiring communication capable supporting networks (e.g., smart metering). Generally, adopted MAC strategy based on pure ALOHA, which, among other things, allows minimize traffic overhead under constrained duty cycle limitations unlicensed bands. Unfortunately, ALOHA suffers from poor scalability, rapidly collapsing in dense networks. This work investigates design an improved scheme slotted ALOHA. In particular, required time dissemination provided by out-of-band communications leveraging FM-RDS broadcasting. An experimental setup hardware used characterize obtainable synchronization performance and derive timing error model. Consequently, improvements success probability energy efficiency have been validated means simulations very with up 10000 nodes. It shown that advantage proposed over conventional 100% when short update payload are required. Similar results obtained regarding improvement, which close relatively transmission intervals long message duration; however, due additional listening messages, gain can be negative short-duration messages fastly repeating.