Game Theoretical Model and Existence of Win-Win Situation for Femtocell Networks

In recent years, the femtocell plays an important role in wireless networks not only for its spectrum reuse but also for its low power consumption. However, there exists several critical issues that need to be investigated, especially for the interferences between the macrocells and the femtocells. Two major access policies are considered in the femtocell network, including the closed access mode and the open access mode. The closed access mode only permits authorized subscribers to utilize the femtocells; while all users are allowed to connect to the femtocell by adopting the open access mode. The closed access will intuitively be advantageous to the femtocell subscribers, however, it has shown that interference from the macrocell to the femtocell can be mitigated by using the open access mode. In this paper, a cell selection game is theoretically modeled to formulate the behaviors of the nonsubscribers who have the opportunities to connect to the femtocells. The distinct connection manners of nonsubscribers to access the macrocells and the femtocells are modeled as the primary users and cognitive users, respectively. Considering the channel capacity of femtocell as the utility function of this game, the existence of a pure strategy Nash equilibrium is illustrated to provide the win-win situation between the subscribers and nonsubscribers.