Competitive Optimization in Gaussian Frequency Selective Interference Channels Using Game Theory

The concept of cognitive radio such as sensing free frequency band and dynamic spectrum access can achieve efficient use of the frequency band in future communication systems. One of the important issues discussed in cognitive radio network is resource allocation. Given the competitive character of the user, in this paper we model a cognitive radio network as a noncooperative game where secondary users compete intractably with each other in frequencyselective channels, by maximizing their own information rates subject to the total transmit power and peak transmit power in each frequency band. We express the solution to the problem in Nash equilibrium form and investigate the existence and uniqueness of the Nash equilibrium. Also, to achieve Nash equilibrium of the game, we use an asynchronous distributed algorithm called smoothed asynchronous iterative water-filling algorithm. This means that some users, among others, will have more opportunity to update their own allocated power.