Extending data transmission in the multi-hop LoRa network

Abstract

In recent years, with the widely available broadband network connectivity and sensing technology, the Internet of Things (IoT) provides a variety of smart services in both urban and rural environments. For example, sensing devices placed in the community not only provide environmental monitoring, but also are used to inform the public about rapidly changing real-time events. The data collected from sensors will help the community improve quality of life of citizens, and can be used for the city development. It has been known that LoRa (Long Range), a notable LPWAN (Low Power Wide Area Network) wireless communication technology, is suitable for providing IoT service with the help of wide coverage, long battery lifetime and low cost to deploy and operate. However, as the application of IoT is becoming increasingly complex, simple sensor data does not satisfy user requirements, and the demand for a variety of multimedia data transmission is increasing. Specifically, many applications require large image data transmission for improved service. A network based on LoRa supports data communication at up to 10 km range with the minimum data rate, and LoRaWAN is operated with a Star-of-Stars topology. However, due to the narrow bandwidth of LoRa, it takes a great deal amount of time to transmit large image files. A possible solution is to reduce distance between sensing devices and a gateway by deploying more gateways and maximize the data rate. However, as expected, particularly in case of monitoring rural environments such as farms, forests, mountains, etc., it is costly to provide the required power and network connectivity for the deployment of additional gateways. As a solution to two challenges, large image transmission and service coverage extension, multi-hop LoRa network is introduced. In this study, we implemented and tested a multi-hop LoRa network. In the experiment, we were able to transmit an image file through multiple end devices successfully.