An improved power control method based on cooperative game for cognitive radio networks

In this paper, in order to decrease the interference between secondary users and primary users, a power control model based on the cooperative game theory has been investigated in the cognitive radio network. According to Nash theorem, a new utility function based on a fairness function is designed, and a new distributed power control algorithm based on Nash Bargaining Solution (NBS) is also put forward. The optimal power levels can be achieved by using Lagrange multiplier method and the iterative formula can also be realized by introducing Newton iterative method. Numerical results show that the new algorithm can realize the effective control over secondary users. In the scenario of primary users coexisted with secondary users, compared with traditional NBS algorithm, the new algorithm can not only ensure the QoS of secondary users, but also realize the interference suppression over primary users.