01364nas a2200133   4500000000100000000000100001008004100002260002300043100002400066700001700090700001900107245007900126520102500205       2022                            d  bIEEEaNice, France1 aTadeusz Czachórski1 aErol Gelenbe1 aGodlove Kuaban00aModelling energy changes in the energy harvesting battery of an IoT device3 a<p>The complexity of battery-powered autonomous de-<br />
vices such as Internet of Things (IoT) nodes or Unmanned Aerial<br />
Vehicles (UAV) and the necessity to ensure an acceptable quality<br />
of service, reliability, and security, have significantly increased<br />
their energy demand. In this paper, we discuss using a diffusion<br />
approximation process to approximate the dynamic changes in<br />
the energy content of a battery. We consider the case when<br />
energy harvesting sources are constantly charging the battery.<br />
The model assumes a probabilistic consumption and delivery of<br />
energy, giving the time-dependent distributions of the energy at<br />
the battery, of the time remaining until it becomes empty, the<br />
time required to charge the battery to its total capacity, or the<br />
time it is operational between two moments of complete depletion.<br />
When possible, we compare the diffusion approximation results<br />
with corresponding Markovian models.</p>