  Increasing threats of global warming and climate changes call for an
energy-efficient and sustainable design of future wireless communication
systems. To this end, a novel two-scale stochastic control framework is put
forth for smart-grid powered coordinated multi-point (CoMP) systems. Taking
into account renewable energy sources (RES), dynamic pricing, two-way energy
trading facilities and imperfect energy storage devices, the energy management
task is formulated as an infinite-horizon optimization problem minimizing the
time-average energy transaction cost, subject to the users' quality of service
(QoS) requirements. Leveraging the Lyapunov optimization approach as well as
the stochastic subgradient method, a two-scale online control (TS-OC) approach
is developed for the resultant smart-grid powered CoMP systems. Using only
historical data, the proposed TS-OC makes online control decisions at two
timescales, and features a provably feasible and asymptotically near-optimal
solution. Numerical tests further corroborate the theoretical analysis, and
demonstrate the merits of the proposed approach.
