A game theory approach: Dynamic behaviours for spectrum management in cognitive radio network

The dynamic behavior for spectrum management in cognitive radio networks is considered in this paper, which consists of spectrum trading and spectrum competition among multiple spectrum owners and spectrum leasers. The primary users adjust their behaviors in renting the spectrum to secondary users in order to achieve higher profits. The secondary users adjust the spectrum renting by observing the changes in the price and the quality of the spectrum. It is however problematic when the primary users and secondary users make the decisions dynamically. A three layer game theoretic approach is introduced in this paper to address this problem. The upper layer models the spectrum competition among primary users; a Bertrand game is formulated where the Nash equilibrium is considered as the solution. The middle layer models the spectrum trading between the primary user and secondary user; a Stackelberg game is formulated where the Nash equilibrium is considered as the solution. The lower layer models the dynamic selection strategies among secondary users in order to select the offered spectrum; an evolutionary game is formulated where the Nash equilibrium is the solution. Basically, the solution in each game is found in terms of the size of the offered spectrum to the secondary users and the spectrum price. The proposed game theory model is used to examine network dynamics under different levels of QoS where the actions of each user are made dynamically.