Research On Power Control Algorithm Based On Underlay Mode In Cognitive Radio Networkes

Underlay mode can effectively improve the utilization of spectrum resources,and power control can ensure normal communication between primary and secondary users.Based on the related theory and technology of cognitive radio networks,this paper uses game theory to study power control.The main work and achievements are as follows:(1)Aiming at the problem of unfairness among the secondary users,a more fair and efficient power control algorithm is proposed in CRN based on the underlay shared mode.The improved utility function can balance the fairness among the secondary users and reduce the complexity of power control algorithm.On the basis of game theory,the game model is proved to be a supermodular game,and the existence and uniqueness of Nash equilibrium are proved.The experimental results show that the proposed algorithm can reduce the transmission power of secondary user and improve the system throughput while increasing the fairness of the secondary user and the benefit of the entire system.(2)In the underlay mode underlay,for the issue that the SU elevate their profits by enhancing transmitting power,the paper proposes the power control for cognitive radio networks based on a game theory.Firstly,under the condition of meeting the normal communication between the main users and the SU,we need to introduce channel condition into utility function so as to increase punishment for rational user's selfishness.Secondly,it need proving that the existence of Nash equilibrium can be found and Nash equilibrium is unique.Finally,the general iterative method is used to find the optimal solution.The experiment shows that the proposed algorithm can reduce the user's transmitting power,have a better anti-background noise ability,and increase the throughput capacity of the system.