Provisioning green energy for small cell BSs

Mobile base stations (BSs) can be powered by green energy in order to reduce the on-grid energy consumption, and subsequently reduce the carbon footprints. However, equipping a BS with a green energy system incurs additional capital expenditure (CAPEX) which is determined by the size of the green energy generator, the battery capacity, and other installation expense. In this paper, we introduce and investigate the green energy provisioning (GEP) problem which aims to minimize the CAPEX on deploying green energy powered BSs while achieving the capacity expansion and traffic offloading target. The GEP problem is challenging because it involves optimization over multiple time slots and across multiple BSs. We propose a heuristic green energy provisioning solution which decomposes the GEP problem into three sub-problems: the traffic load optimization problem, the active BS selection problem, and the green energy system sizing problem. We propose algorithms to solve the sub-problems and subsequently solve the GEP problem.