Duty Cycle Optimizing for WiFi-based IoT Networks with Energy Harvesting

In this paper, we propose a simple method to optimize the duty-cycle of an IoT network equipped with energy harvesters. The main objective is to achieve Energy Neutral Operation (ENO) so that the devices can operate autonomously for longer periods. We use an exponentially weighted moving-average (EWMA) filter to predict the energy harvested in a single duty-cycle, and adjust the duty-cycle according to the energy required during the active periods. As a case study, we consider the use of the carrier sensing medium access (CSMA) Medium Access Control (MAC) protocol in a data collection application where a WiFi access point investigates a group of IoT devices equipped with energy harvesting circuit. We evaluate the performance of the proposed scheme with the help of simulations. The results show that an optimal configuration of the prediction filter can help to reach the ENO condition and ensure the unlimited lifetime of the network.