Outage estimation for solar powered cellular base stations

Solar powered cellular base stations are emerging as a key solution in green cellular networks. A major challenge in the design of such a base station (BS) is finding the optimal cost configuration of the photo-voltaic (PV) panel size and number of batteries which meets a tolerable outage probability with the least cost. One of the fundamental steps in this process is to calculate the outage probability associated with a particular PV panel size and battery size configuration. To address this issue, this paper proposes an analytic model to evaluate the outage probability of a solar powered BS. The proposed model factors in the daily and hourly variations in the harvested solar energy and the traffic dependent BS load, and develops a discrete-time Markov process to model the battery level and thus the outage probability of the BS. Simulation results with empirical solar irradiance data for three different locations are used to validate the proposed model and demonstrate its accuracy.