LoRa in the Field: Insights from Networking the Smart City Hamburg with RIOT

Abstract

Inter-connected sensors and actuators have scaled down to small embedded devices such as wearables, and at the same time meet a massive deployment at the Internet edge---the Internet of Things (IoT). Many of these IoT devices run on low-power batteries and are forced to operate on very constrained resources, namely slow CPUs, tiny memories, and low-power radios. Establishing a network infrastructure that is energy efficient, wireless, and still covers a wide area is a larger challenge in this regime. LoRa is a low complexity long range radio technology, which tries to meet these challenges. With LoRaWAN a network model for widespread deployment has been established, which enjoys open public LoRaWAN dissemination such as with the infrastructure of TheThingsNetwork. In this paper, we report about our experiences with developing and deploying LoRa-based smart city applications as part of the MONICA project in Hamburg. Our contributions are twofold. First, we describe the design and implementation of end-to-end IoT applications based on the friendly IoT operating system RIOT. Second, we report on measurements and evaluations of our large field trials during several public events in the city of Hamburg. Our results show that LoRaWAN provides a suitable communication layer for a variety of Smart City use-cases and IoT applications, but also identifies its limitations and weaknesses.