An analysis of energy consumption under various memory mappings for FRAM-based IoT devices

Abstract

Internet of Things (IoT) devices are powered by an independent power supply like battery and energy harvester, which provide limited energy. Batteries require charging and replacement due to their limited lifetime. Energy harvesters have a semi-permanent lifetime but are environmentally constrained and irregularly supplied, which can cause power failure problems. Reducing the energy consumption of IoT devices can alleviate problems caused by independent power supplies. In general, the memory of IoT device is used for storing programs and data, executing tasks, and so on. The consistent access to the memory occurs while the IoT device is operating. Thus, the energy savings in accessing memory reduce the average IoT device energy consumption. This can help alleviate the problem of independent power supplies. In this paper, we analyze the energy consumption pattern according to memory mapping of tasks using a FRAM-based embedded device. We also analyzed the energy consumption of the low-power mode according to the memory mapping. Considering the overhead of data migration depending on the task, we confirmed that an average of 50% energy saving is possible when the proper memory mapping is selected.