When LoRaWAN Frames Collide

LoRa, an abbreviation of Long Range, is a Low-Power Wide Area Network (LPWAN) radio technology that has quickly gained popularity as a communications means for the Internet-of-Things (IoT). LoRa is typically used together with the MAC protocol LoRaWAN and operates in the license-free ISM-bands. As such, anyone is allowed to deploy their own LoRaWAN network, provided that they adhere to the LoRaWAN specification and ISM regulations. However, an uncoordinated deployment of LoRaWAN networks may cause neighboring networks to interfere and LoRaWAN frames to collide. In this paper, we present an in-depth investigation of LoRaWAN frame collisions -- and the capture effect in particular -- through various experiments. Contrary to previous research, we focus on correct reception of data at the application, instead of at the gateway, and we consider multi-gateway, multi-provider, and dense scenarios to obtain insight into collisions within actual networks.