Network densification is currently seen as one ofthe key techniques enabling Radio Access Networks (RANs) tomeet the performance and functional requirements of the 5Gparadigm in urban areas. Avoiding the connection of small cellsto the power grid facilitates their deployment and reduces bothcapital and operational expenditures (CAPEX and OPEX). Inthis paper, we propose an approach to enable net-Zero EnergyNetworking (ZEN) in urban scenarios, based on dynamicallymanaging the operating point of Base Stations (BSs), so as todrastically decrease their overall energy requirements. Morespecifically, we formalize the problem of optimizing the CAPEXof a ZEN, while guaranteeing quality of service (QoS) and agiven level of service availability. Optimization is over powersystem parameters (solar panel area, battery capacity) as wellas over BS power levels and user association over time. Wepropose a practical algorithm for the derivation of QoS-awarespatio-temporal strategies in terms of user association andBS power allocation, which, for a given expected patternof renewable power generation, minimize the probability ofservice unavailability due to power shortage. Through extensivesimulations using measured data, and realistic BS deployments, we show that our algorithm leads to substantial reduction inCAPEX, and to feasible power system requirements.
['Gianluca Rizzo', 'Marco Ajmone Marsan']
QoS-Aware CAPEX Minimization in Urban Off-Grid Radio Access Networks