SPARC-LoRa: A Scalable, Power-efficient, Affordable, Reliable, and Cloud Service-enabled LoRa Networking System for Agriculture Applications

With the rapid development of cloud and edge computing, Internet of Things (IoT) applications have been deployed in various aspects of human life. In this paper, we design and implement a holistic IoT system with LoRa communication capabilities, named SPARC-LoRa, which consists of field sensor nodes and a gateway connected to the Internet. SPARC-LoRa has the following important features. First, the proposed wireless network of SPARC-LoRa is event-driven and using off-the-shelf microcontroller and LoRa communication modules with a customized PCB design to integrate all the hardware. This enables SPARC-LoRa to achieve low power consumption, long range communication, and low cost. With a new connection-based upper layer protocol design, the scalability and communication reliability of SPARC-loRa can be achieved. Second, an open source software including sensor nodes and servers is designed based on Docker container with cloud storage, computing, and LTE functionalities. Furthermore, in order to achieve reliable wireless communication under extreme conditions, a relay module is designed and applied to SPARC-LoRa to forward the data from the sensor nodes to the gateway node. The server side software platform consists of 1) MQTT protocol publishing measured data from the gateway node to the cloud servers using LTE connections; 2) InfluxDB database for data storage; and 3) Grafana data web server for accessing the measured data from any platforms or web browsers. The system design and implementation is completely open source and hosted on the DigitalOcean Droplet Cloud. Hence, the proposed system enables further research and applications in both academia and industry. Finally, the proposed system has been tested in real fields under different and extreme environmental conditions in Salt Lake City, Utah and the University of Nebraska-Lincoln. The experimental results validate the features of SPARC-LoRa including low power, reliability, and cloud services provided by SPARC-LoRa.