Increased flexibility in long-range IoT deployments with transparent and light-weight 2-hop LoRa approach

LoRa is a recent low-power and long-range sub-GHz radio technology where devices can communicate in 1-hop to a gateway several kilometers away. Long-range radios typically remove the complexity of maintaining a multi-hop network with intermediate nodes for relaying information. Nonetheless, even with the increased range, 1-hop connectivity can be difficult to achieve in real-world deployment scenario, especially for remote and rural areas where density of gateways is low and where devices/gateway are usually deployed for a specific application. This article describes a 2-hop LoRa approach to seamlessly extend a deployed LoRa network in order to reduce both packet losses and transmission cost. We introduce a smart and battery-operated relay-device that can be added after a deployment campaign to transparently provide an extra hop between the remote devices and the gateway. Field tests are conducted to assess network reliability by dynamic insertion of a relay-device between the remote end-devices and the gateway, without advertising its presence. Energy consumption is also discussed.