Performance evaluation of the Over-The-Air activation procedure in a large scale LoRaWAN

LoRaWAN is a promising LPWAN technology for IoT connectivity. It offers long-range and wide-area communication at low-power, low cost and low data rate. LoRaWAN performance has been evaluated according to many features such as coverage, scalability, physical layer parameters, communication reliability and latency. Existing studies assume that the LoRaWAN end-devices are already connected to the LoRa NetServer. Therefore, the performance of LoRaWAN activation procedure has not been well investigated. In this work, we study the performance of LoRaWAN during the Over-The-Air activation procedure. This process enables a large number of end-devices to join the network before being able to exchange any kind of packets. Thus, we analyze the average activation delay and the average energy consumption for an end-device in a large scale LoRaWAN. To achieve this goal, we first implement the Over-The-Air activation procedure in ns-3, especially in the ’lorawan’ module and conduct extensive simulations. Then, we elaborate a mathematical model using Markov-chain to evaluate both the delay and the energy consumption analytically. Our study shows that in a LoRaWAN cell composed of 1000 end-devices, the average activation delay for an end-device is about 35 minutes and this activation requires an average of three join-packet transmissions and an average energy consumption of 0.0887J.