Experimental Evaluation of a Campus-Deployed IoT Network Using LoRa

The emergence of the Internet of Things (IoT) has redefined sensor networking with an unprecedented increase in the number of applications leveraging sensor technology in a myriad of domains. This has also revolutionized the communication technology required to network these sensors to exploit their potential. Short range wireless technologies provide high data rate and typically operate in the unlicensed band. Cellular technologies on the other hand provide relatively longer range, higher data rate and operate in the licensed spectrum. The need to bridge the gap between these two, i.e., provide a low cost and longer range solution with the ability to connect massive number of geographically spread out devices using the unlicensed spectrum led to the emergence of Low Power Wide Area Networks (LPWAN). Long Range (LoRa), one of the LPWAN technologies continues to attract attention given its open specification and ready availability of off-the-shelf hardware with claims of several kms of range in harsh challenging environments. In this paper we put these claims under test through extensive measurements carried out over a test-bed deployed in a University campus. The conducted tests focused on the link quality and transmission performance based on various parameters such as the spreading factor (SF), coding rates (CR), bandwidth for different radio propagation scenarios. Findings from this study show that the achievable performance can greatly vary and prompts caution when taking numbers at face value as this can have implications for the IoT applications.