A simple analytical model for the BS lifetime

We propose a simple analytical model to evaluate the base station (BS) lifetime subject to power state changes (i.e., transmitted power or a sleep mode (SM)). We first consider the effect of setting the power state, and the impact of transitions occurring between the power states. We then build a model to compute the probability distribution of lifetime for a single BS, given the hardware (HW) parameters and the transition probabilities between the power states. Our results, obtained over a 4G scenario, show that frequent power state changes may deteriorate the BS lifetime. However, if the BS survives for a sufficient amount of time, then the impact on the lifetime is reduced. Finally, we have compared the costs due to the reduction of lifetime (i.e., reparation and replacement of BS HW) with the monetary savings introduced by the energy-aware policies.