  With energy-efficient resource allocation, mobile users and base station have
different objectives. While the base station strives for an energy-efficient
operation of the complete cell, each user aims to maximize its own data rate.
To obtain this individual benefit, users may selfishly adjust their Channel
State Information (CSI) reports, reducing the cell's energy efficiency. To
analyze this conflict of interest, we formalize energy-efficient power
allocation as a utility maximization problem and present a simple algorithm
that performs close to the optimum. By formulating selfish CSI reporting as a
game, we prove the existence of an unique equilibrium and characterize energy
efficiency with true and selfish CSI in closed form. Our numerical results show
that, surprisingly, energy-efficient power allocation in small cells is more
robust against selfish CSI than cells with large transmit powers. This and
further design rules show that our paper provides valuable theoretical insight
to energy-efficient networks when CSI reports cannot be trusted.
