An improved LoRaWAN protocol based on adaptive duty cycle

In the low power wide area network, the LoRaWAN protocol adopts ALOHA type to access channel without duty cycle limited. The energy-efficient of the node and the robustness for varying traffic load are not considered in the situation which may lead to unfairness of node. To balance the energy consumption and network performance, an adaptive duty cycle medium access control (ADC-MAC) protocol is proposed. The basic idea of the protocol is that each sensor node maintains three indicators including the residual energy, the node load and the network congestion rate. The sensor node selects a different duty cycle to control the minimum interval of the uplinks. The asynchronous scheme is easier to implement as time synchronization is not necessary. The results, acquired by OPNET, demonstrate that the proposed ADC-MAC protocol have obvious advantages in extending the battery lifetime and improving packet delivery rate.