Time-Slotted LoRa Networks: Design Considerations, Implementations, and Perspectives

In recent years, LoRa and LoRaWAN have emerged as a promising Low-Power Wide Area Networking (LPWAN) technology for long-range low-throughput applications. Lo-RaWAN, however, is based on unregulated medium access, and thus cannot provide high packet delivery guarantees. This limitation, indeed, hinders the suitability of LoRaWAN for Industrial Internet of Things applications. In this article, we explore time-slotted medium access protocols as a reliable alternative to LoRaWAN, focusing on the considerations, challenges and perspectives for designing time-slotted protocols that leverage LoRa at the physical layer. The article is particularly focused on protocols with either a proof-of-concept implementation or protocols that have been deployed in the real world.