Abstract/Summary

LoRa is one of the most promising techniques for the Internet of Things (IoT), and it has attracted considerable attention. Most existing LoRa applications follow the LoRaWAN specification and adopt a star topology. However, LoRaWAN networks are typically limited by their scalability due to the use of a centralized control strategy. The recent development of LoRa-Mesh networks can be a potential solution to this limitation. In this article, we propose a hierarchical-based energy-efficient (HBEE) routing protocol as a desirable method for building LoRa-Mesh networks. The HBEE exhibits the following advantages: 1) it can quickly build the network structure during the network formation stage by using contention-free concurrent transmission; 2) during the routing exploration phase, end-device nodes (ENs) can locate parent ENs with a minimized overhead; and 3) at the data collection stage, packet collision is minimized using multipath and multichannel routing method. Simulations are conducted to evaluate the performance of HBEE, and the results show that HBEE outperforms conventional ad hoc on-demand distance vector routing (AODV) protocol in terms of energy efficiency and transmission delay. Finally, proof-of-concept experiments are implemented in the real world. The results show that the packet reception rate of 95.7% and 89.8% can be achieved during network formation and normal operation phases, respectively.