부산대학교 도서관

LoRaWAN is a low-power wide-area network (LPWAN) protocol based on LoRa technology, which is mainly used in the field of IoT. While LoRaWAN Network can achieve long-distance, low-cost, and large-capacity wireless communication, it encounters challenges in improving the reliability, efficiency, and scalability of networks. In order to address these challenges, we specifically delve into the study of the adaptive data rate (ADR) mechanism. ADR is a crucial component that dynamically manages the data rate and transmission power of each terminal device. Additionally, we also investigate the initial allocation of spreading factors to enhance ADR's adaptability in more complex network scenarios. There are three main contributions in this paper: Firstly, we propose an improved ADR mechanism based on device average transmission cycle, which can dynamically adjust the data rate according to the transmission behavior of terminal devices, so that to reduce network congestion, increase network throughput, and enhance adaptivity to different network scenarios. Secondly, in order to further improve the performance of our ADR mechanism, we have proposed a spreading factor allocation method based on airtime, which can assign suitable spreading factors for terminal devices in the initial stage, and improve the network coverage and transmission efficiency. Finally, the improved ADR and initial SF allocation are implemented on NS3 simulation platform, and compared with other ADR mechanisms under different network traffics. The results show that our proposed ADR mechanism and initial SF allocation method can improve the performance of LoRaWAN network effectively.