Hyeong-Kyu Lee, MinGyu Lee and Tae-Jin Lee, Sungkyunkwan University, South Korea

In energy harvesting IoT networks, an energy queue state of an IoT device will change dynamically and the number of IoT devices that transmit data to the IoT AP will vary in a frame. So we need a MAC protocol to adjust the frame length taking the amount of energy of IoT devices into consideration. Since the existing Framed slotted ALOHA (F-ALOHA) Medium Access Control (MAC) protocol utilizes the fixed frame size, the resource efficiency can be reduced. In this paper, we propose a Harvested Energy-adaptive Medium Access Control (HE-MAC) protocol where an IoT Access Point (AP) allocates slots in accordance with the number of IoT devices that try to transmit data in a frame. The proposed HE-MAC protocol improves the resource efficiency of the F-ALOHA MAC protocol. We show that the resource efficiency of the HE-MAC protocol is superior to those of the F-ALOHA MAC protocol through simulations.

Internet of Things, Energy Harvesting, Framed Slotted ALOHA, Medium Access Control.