부산대학교 도서관

Currently, most IoT services are hosted centralized in a cloud. However, they rely on data gathered by numerous distributed sensors, which require to be connected to these clouds. At the moment this is realized with non-IP based proprietary wireless sensor networks that use inflexible networking concepts and require to be carefully configured. The Thread protocol, with its implementation OpenThread, is a new wireless mesh approach to solve this problem. OpenThread is maintained by the Thread group, which is an organization supported by almost 300 companies, including Google, Amazon, and Apple. Its design is based on an IPv6, for seamless integration in existing IP networks. This work, after a short a practical overview of the Thread protocol in general, investigates the network performance in different interference scenarios based on results from a hardware testbed, set up in an office building. This testbed is based on the Nordic Semiconductor nRF52840 System on a Chip (SoC), running OpenThread from the official github repository. Besides a thorough examination for round-trip-time (RTT) and losses, a stability test was performed over five weeks, to see the impact of interference during business hours. We measured RTTs in the range of 10 to 100 ms and losses up to 40 % depending on interfering wireless services. Despite its obvious advantages, from our experimental results, it is evident how some practical limitations make Open Thread not always a good choice.