Accelerating Update Broadcasts Over LoRaWAN Downlink via D2D Cooperation

Broadcast distribution of updates (e.g., security patches, machine learning models) from a server to end devices (EDs) is a critical requirement in the Internet of Things (IoT). In this paper, we consider the problem of reliable over-the-air broadcast of updates in Long Range Wide Area Networks (LoRaWANs). Existing broadcast techniques for LoRaWANs suffer from long delivery delays due to low data rates and duty-cycle constraints. We address this problem by proposing a device-level cooperative mechanism, in which updated EDs broadcast a few update fragments to accelerate delivery to their neighbors. We demonstrate large reductions in the delivery time compared to conventional methods. For instance, in a 400-node network spanning 1 km radius and operating at 1% duty-cycle, the proposed scheme reduces the time required to deliver a 10 kilobyte update to an ED at the network's edge from 42 hours to 45 minutes. The proposed solution thus provides a pathway toward improved security and efficient realization of edge intelligence in LoRaWAN IoT.