Towards Next-Generation Global IoT: Empowering Massive Connectivity with Harmonious Multi-Network Coexistence

LoRaWAN offers a compelling solution for delivering cost-effective network access to millions of IoT devices worldwide. However, operators face challenges in scaling their services to meet the growing demands of IoT connections. Moreover, current LoRaWANs foster competition rather than cooperation among coexisting networks, resulting in substantial capacity degradation as network density increases. To identify the root causes limiting LoRaWAN scalability and to enable harmonious coexistence among network operators, this paper conducts an in-depth investigation of operational Lo-RaWANs. For the first time, our study reveals that the capacity degradation in LoRaWAN is not due to the traditionally believed issues (such as interference or packet collisions in the wireless medium) but rather a newly identified issue termed decoder contention problem. This problem cannot be effectively resolved using conventional approaches and will significantly hinder the scaled deployment of LoRaWANs as a next-generation global infrastructure. Based on our new findings, we propose design principles that guide our exploration for effective strategies to address this emerging practical problem. We develop concrete deployable solutions to mitigate contention, optimize spectrum utilization, and promote spectrum sharing among network operators. Extensive evaluations demonstrate that our strategies effectively boost network capacity close to the theoretical bound, and support the coexistence of up to six networks with significant improvement in spectrum efficiency.