In this paper, we study the sharing of a radio access network infrastructure by two mobile operators. Knowing the possible locations of the base stations, each operator chooses to invest or not on a base station, and its aim is to maximize its profit. We characterize the existence of Nash equilibria in such a game and we measure their quality with respect to the maximization of the overall profit (with the price of anarchy/stability). We then show how to obtain a solution in which each operator earns at least as much as it would have earned in any Nash equilibrium. Finally we conduct experiments on randomly generated instances and on real data.