A stochastic power control game for two-tier cellular networks with energy harvesting small cells

Energy harvesting in cellular networks is an emerging technique to enhance the sustainability of power-constrained wireless devices. This paper considers the co-channel deployment of a macrocell overlaid with small cells. The small cell base stations (SBSs) harvest their energy from environment sources whereas the macro base station (MBS) uses conventional power supply. Given a stochastic energy arrival process, this paper derives a power control policy for the downlink transmission of both MBS and SBSs such that they can obtain an equilibrium of their own objectives on a long-term basis (e.g., maximizing the transmission rate for SBSs while maintaining the target signal-to-interference-plus-noise ratio (SINR) at the macro users) on a given transmission channel. To this end, we propose a single controller stochastic game and develop a power control policy as a solution of a quadratic programming problem. Numerical results demonstrate the significance of the developed optimal power control policy over the conventional fixed and random power control policies.