LoRa for the Last Mile Connectivity in IoT

Cost-effective, low-power and wireless connectivity are among the key considerations for interconnecting the end-nodes or end-devices in the Internet of Things (IoT) applications. While wireless technologies such as WiFi, Bluetooth, Zigbee have been popular choices for last-mile connectivity, they however significantly restrict the distance between the communicating entities. While the use of additional network gear like repeaters or higher signal transmission power would increase the range of these wireless communication interfaces, the consequent increase in the cost has been a critical reason for not readily employing them in WAN based IoT applications such as Smart Cities. The emergence of the LoRa (Long Range) standard and the Low Power Wide Area Network (LPWAN) technology, in recent times, have however widened the scope and also broadened the deployment scenarios of the IoT end-nodes including the viability of the battery-powered and non-stationary ones. Yet another significance of these new long-distance-low-power interconnect standards is the empowerment for broader and independent Machine to Infrastructure (M2I) and Machine to Machine (M2M) communication for the end-nodes. This paper discusses details of the work that was carried out to explore the suitability of LoRa and LoRaWAN to address the short as well as the medium-range connectivity requirements of the IoT applications while also ensuring the flexibility and low-cost benefits with the help of results obtained from the representative experimental setups. The overall study and assessment were performed in steps, each with specific objectives. The first step was aimed at evaluating the performance of LoRa for communication between stationary as well as moving nodes. The next step was directed towards the validation of node-to-gateway and node-to-node communication, and also, with simultaneous use of different channels within LoRaWANs that were configured in star and mesh topologies. The subsequent step was devoted to assessing the viability of LoRa in broader IoT applications such as Smart Cities and Smart Irrigation, with the help of an illustrative setup comprising of nodes with sensors and actuators and, a gateway which was connected to an open-source cloud infrastructure to epitomize aspects of storage and analysis of data of a comprehensive IoT deployment.