Distributed power optimization for spectrum-sharing femtocell networks: A fictitious game approach

Power control techniques are becoming increasingly important for a two-tier network, where a central macrocell is underlaid with femtocells, since cross-tier and co-tier interference severely limits network performance. In this paper, we propose a distributed power control scheme for the uplink transmission of spectrum-sharing femtocell networks based on fictitious game. Each user announces a price that reflects its sensitivity to the current interference level, and adjusts its power to maximize its utility. Power and price are updated at terminals and base stations, respectively. The scheme is proved to converge to a unique optimal equilibrium. Furthermore, we propose a simple macrocell link protection scheme, where a macro user can protect itself by increasing its price. Most importantly, we investigate the power optimization scheme proposed in frequency-selective channels based on the Stackelberg game, in which each user prices its limited power allocated to subchannels. Numerical results show that the proposed schemes are effective in resource allocation for spectrum-sharing two-tier networks.