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Dynamic Backoff Based Access Mechanism for LoRaWAN Class A

LoRaWAN is a popular technology in Low Power Wide Area Networks(LPWANs). It can be applied to the smart agriculture, smart building, logistics tracking, disaster monitoring, and so on. The Class A terminal device in LoRaWAN adopts the pure ALOHA access mode. It has the problems of low channel utilization, high access delay and high collision probability. In this paper, we mainly study the access process of Class A devices in LoRaWAN, and derive the mathematical analytical model. To solve this problem, we propose a enhanced access mechanism, dynamic backoff mechanism. The backoff window size would be adaptively adjusted according to the access user attempts. The results show that our model is correct and the proposed scheme can effectively improve the successful access probability for LoRaWAN nodes.