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.

翻译：在物联网中，从服务器向终端设备广播分发更新（如安全补丁、机器学习模型）是一项关键需求。本文研究了远距离广域网中通过无线方式可靠广播更新的问题。现有LoRaWAN广播技术因低数据速率和占空比限制而存在传输延迟过长的问题。我们通过提出一种设备级协作机制来解决此问题，在该机制中已完成更新的终端设备向相邻设备广播少量更新片段以加速传输过程。实验证明，与传统方法相比，该方案能大幅缩短传输时间。例如，在半径为1公里、占空比为1%的400节点网络中，将10千字节更新传输至网络边缘终端设备所需的时间从42小时减少至45分钟。因此，所提方案为提升LoRaWAN物联网安全性和实现高效边缘智能提供了可行路径。