Open YPEC 2021

ON04-Medium Access Control with Efficient Medium Utilization

Internet of Things (IoT) enables the possibility of the smart city in which devices and environmental status could be remotely monitored, managed, and controlled. Low Power Wide Area Network (LPWAN) connecting a large number of devices in a large area with high energy efficiency is the cornerstone technology in an IoT system. Several potential IoT solutions have been proposed to meet the requirements of LPWAN, including LTE-M and Bluetooth Low Energy (BLE). LoRa has the features of large coverage, low power consumption, low cost, and resistance to noise. These physical properties make LoRa be the next emerging IoT solution for building LPWAN. However, the existing LoRaWAN medium access control (MAC) only offers the pure ALOHA method designed for low duty cycle applications. Severe collisions are expected if a large-scale system is launched. Therefore, in this project, multiple MACs with the features of pure ALOHA, slotted ALOHA, IEEE 802.11, IEEE 802.15.4, and channel activity detection (CAD) were proposed and tested by experiments. The performances of the MACs were evaluated by comparing the packet delivery ratio (PDR) and data throughput in bits per second (bps). Almost 100% PDR and a maximum of 4800 bps were achieved by one of the proposed MAC.