The Research Of Power Control In Cognitive Radio Networks

With the wireless information coming, the wireless communication technology isdeveloping very rapidly, and has been widely used in various fields, so that the very tight ofwireless spectrum resources has become more precious. To take full advantage of wirelessresources, People have to find efficient and reliable technology for the spectrum utilization.The cognitive radio (Cognitive Radio, referred to as CR) is the best program to improve thespectrum utilization and use the idle band of the various regions and time periods fully andeffectively. But in cognitive radio systems, the mostly reason of interference to other users isthe cognitive users’(non-authorized users’) transmission power, and the performance of thewireless transmission system is also direct impact by the originator of the power control.Therefore, the power control in cognitive radio systems is a key technology, in the CR, thegame theory is commonly used to solve the problem of power control.The main work of this paper is to study the problems of power control in cognitive radionetwork and improve the models of the original non-cooperative game and joint powercontrol. The innovative work is mainly following two aspects:1. Introduced the concept and development of cognitive radio, and described thepurpose and significance of the cognitive radio power control technology.2. Analyzed the architecture of cognitive radio and some key technologies such asspectrum sensing, spectrum allocation and transmit power control, introduced some basicconcepts of the game theory such as Nash equilibrium and optimal Pasto, and comparedspecial types of the game theory model.3. Introduced the application of game theory in power control and analyzed the powercontrol game model. Based on the interference generated by the cognitive users to the primaryusers, the interference between the cognitive users and the system resource allocation fairnessto different cognitive users, this article redesign the price mechanism and add a controllableadjustment factor to improve the power control model. On that basis, the article gives rigorousmathematical analysis and proves the Nash equilibrium existence and uniqueness and the bestof Pasto. The superiority of new algorithm was proved by simulation analysis.4. The rate unequal allocation is out of the consideration in the original non-cooperative joint power and rate control game. To improve this, the article resets the rate fairness factorcombined the rate unequal allocation fully considering the power control problem. On thisbasis, the article redesigns a new price mechanism to solve the interference and fairnessbetween different cognitive users, which improve the original model. The new model canreflect the fairness between the cognitive system users better. The Nash equilibrium existenceand uniqueness and the best of Pasto of the new model were proved by simulation analysis.The superiority of new algorithm was proved by simulation analysis.