Towards End-to-End Latency of LoRaWAN: Experimental Analysis and IIoT Applicability

In this work, the components that contribute to the effective end-to-end latency of unconfirmed LoRaWAN class A data transmission are identified and measurements of two typical real-world LoRaWAN scenarios with different types of backhaul connection to the network and application server, namely localhost and an intermediate UMTS cellular network are presented. The paper introduces the instrumentation for the analysis of end-to-end latency seen by the end-user application. For two specific network scenarios performance evaluations with regard to latency using different parametrization of spreading factor and payload size are carried out. The analysis shows that LoRaWAN may be applicable for selected Industrial IoT use cases where lower Spreading Factors (SF) are adequate, resulting in an achievable end-to-end delay of below 400 ms. For long distance transmission up to 15km requiring a high SF, the end-to-end latency is well above one second and far beyond real-time availability of sensor data.