| Cognitive radio technology can effectively control and reduce interference. Therefore, it can be applied to all existing spectrum sharing systems to solve the problem of spectrum sharing interference and lack of spectrum resources. So the goal of cognitive radio technique is to improve the spectrum utilization and the core of that is to reduce interference. Thus power control technology has become one of research hotspots and key technologies in cognitive wireless networks.Based on the literature and research situation in recent years, the optimization power control game algorithms are proposed, and the case that the PU transmits with multiple levels of power is considered and the corresponding optimal sensing rule is derived and the primary transmit power is estimated.. Research works and innovations are described as follows.(1) A joint power and rate control using game theory algorithm is proposed in heterogeneous networks environment with interference among different systems. It designs a novel revenue function based on the fairness of users’power control and the rate allocation, accompanying with the primary users received the interference caused by different users. The existence and uniqueness of the Nash equilibrium of game theory is derived by rigorous mathematical. Furthermore, simulation results show that the proposed algorithm can improve the users’ power control and rate allocation significantly.(2) Considering the authorized users’ interference limits, this article combines Underlay and Overlay as a joint optimization algorithm on hybrid spectrum sharing in cognitive network. System capacity is maximized in a series of constraints to ensure services of Underlay below interference threshold of an authorized user; services of Overlay are used to meet user’s needs. To reduce the computational complexity of the node, this article proposes a low complexity suboptimal power allocation algorithm. By solving the objective function, the optimal allocation of bandwidth and power are achieved. Simulation shows that the performance of the algorithm described in this article can effectively improve the throughput performance of the system and can ensure the primary users system’s performance while guaranteeing the QoS of cognitive users.(3) In a centralized network architecture for multi-level case the primary user transmission power, we propose a joint bandwidth and power allocation based on cooperative power control algorithm. The algorithm takes into account the impact of bandwidth and power of cognitive radio network total channel capacity and total channel capacity of a multi-objective function optimization. As can be seen from the simulation results, the scenario closer to reality than sharing the bandwidth allocation, the paper optimization algorithms are able to significantly improve performance in all aspects of service quality, anti-interference ability and other systems. |
