  In this paper, a green wireless communication system in which base stations
are powered by renewable energy sources is considered. This system consists of
a capacity-constrained renewable power supplier (RPS) and a base station (BS)
that faces a predictable random connection demand from mobile user equipments
(UEs). In this model, the BS powered via a combination of a renewable power
source and the conventional electric grid, seeks to specify the renewable power
inventory policy, i.e., the power storage level. On the other hand, the RPS
must strategically choose the energy amount that is supplied to the BS. An
M/M/1 make-to-stock queuing model is proposed to investigate the decentralized
decisions when the two parties optimize their individual costs in a
noncooperative manner. The problem is formulated as a noncooperative game whose
Nash equilibrium (NE) strategies are characterized in order to identify the
causes of inefficiency in the decentralized operation. A set of simple linear
contracts are introduced to coordinate the system so as to achieve an optimal
system performance. The proposed approach is then extended to a setting with
one monopolistic RPS and N BSs that are privately informed of their optimal
energy inventory levels. In this scenario, we show that the widely-used
proportional allocation mechanism is no longer socially optimal. In order to
make the BSs truthfully report their energy demand, an incentive compatible
(IC) mechanism is proposed for our model.
