Competitive spectrum allocation in cognitive radio based on idle probability of primary users

Cognitive radio is recognized as an efficient way to improve the spectrum efficiency. In the distributed cognitive radio networks of multiple primary users and a secondary user, we proposed a utility function based on idle probability of primary users by using game model. The primary users can achieve the Nash equilibrium by adjusting the learning rate through repeated games. Simulations show that the primary user whose idle probability is larger, the system utility is higher and the system utility becomes the largest when the spectrum offered by primary users is totally idle. Besides, the Nash equilibrium is not efficient as the total profit of the primary users is not maximized. The cooperative optimality solution can obtain the highest system profit finally.