Robust Power Control for Heterogeneous Users in Shared Unlicensed Bands

We develop a robust formalism for power control games in unlicensed bands between two groups of users competing for the spectrum: informed-users (leaders) who have advanced capabilities to extract side-information about other users and their strategies, and uninformed-users (followers) who can only observe the aggregate interference caused by others. Such nominal leader-follower games have been previously studied in the power control literature; however, these prior works fail to capture an important aspect of such interactions: the side-information and observations made by users may be uncertain, which has an important impact on users´ strategies and network performance. Thus, in this paper we propose a new, robust game-theoretic formalism and solution which takes these uncertainties into account. Specifically, each group chooses its actions by solving its respective worst-case robust optimization problems. We show how various types of uncertainties affect the social utility of each group, and identify in which deployment scenarios the social utility of the robust game is higher than that of the nominal game. Importantly, we show that robust solutions in such games are more energy efficient. Finally, our theoretical formalism, analysis and solutions are complemented by simulations.