Abstract: We studied joint power and rate control for cognitive radios in the underlay type. Power control is one of the key technology in cognitive radio,and the next generation wireless systems also will be required to support with different transmission rates. In this paper we assumed the problem between second users as a non-cooperative game, and one power control algorithm was proposed,subject to the tolerable interference limits. And it is proved that the Nash ectuilibrium of the algorithm is the existence, uniqueness, the simulation results show that the method has a faster convergence, and can converge to the lower power and higher rates.

Key words: Cognitive radio, Uame theoretic, Power control, Rate control