Introducing Scalability in LoRa-Based Networks through Multi-Hop Communication Setups

The long range and low-power operation of Low- Power Wide-Area Network (LPWAN) communication technologies make them an attractive choice for many Internet of Things (IoTs) use cases. Among existing LPWAN technologies, Long Range (LoRa) is most popular. LoRa PHY layer supports a number of communication settings. The PHY layer settings impact coverage, reliability, and energy consumption. LoRaWAN is the standard MAC layer for LoRa, and the LoRaWAN documentation recommends using LoRa PHY layer setting that provides long range and higher resilience against interference. However, the communication setting's long range and higher resilience against interference result in higher energy consumption and lower data rate. There also exists the LoRa PHY layer communication setting that can yield fastest data rate and low energy consumption, however it reduces coverage and reliability. As the fastest data rate setting results in shorter coverage and lower energy consumption, therefore here we investigate the use of multi- hop communication along with the fastest data rate setting to exactly match the coverage of LoRa PHY layer setting recommended by LoRaWAN. We extensively evaluated our multi-hop communication setups against the LoRaWAN communication setup and its recommended PHY layer communication setting. In our experiments, we analyze the impact of different data traffic generation models and different node densities on a LoRa network's performance. Moreover, we also analyze the impact of the number of relaying nodes at different multi-hop levels on a network's throughput, reliability, and energy consumption. Our results demonstrate that our multi-hop communication setups can provide up to $13$ times higher packet delivery ratio and up to $60\%$ lower energy consumption compared to the LoRaWAN communication setup and its recommended communication setting.