Research On Spectrum And Resource Allocation Mechanism In Cooperative Cognitive Network

With the rapid development of wireless communication and the increasing demand for communication between users,the contradiction between the ever-increasing wireless service and the ever-decreasing radio spectrum resources becomes more and more obvious.Cognitive radio technology,which aims at easing this contradiction and breaking the traditional mechanism in the management and usage of spectrum resources,has gained a significant development in the past years.This technology becomes the foundation of dynamic spectrum management.Under this technical framework,the secondary users are able to reutilize the frequency band of authorized network to communicate.Besides,cooperative communication can utilize broadcast characteristics of wireless space,so that single-antenna terminals will cooperate with each other to obtain the spatial diversity gain.Therefore,the combination of both,namely cooperative cognitive network can effectively improve the transmission performance of wireless network.At present,researchers on the allocation of resources in cognitive network are mainly optimization of throughput and energy efficiency in secondary user system.However,these researchers do not fully consider the characteristics of the secondary users,such as selfishness and autonomy right.Based on the above considerations,the main contributions of this thesis are listed as follows:Firstly,the scheme of resource allocation based on participation of secondary users in the scenario of energy harvesting is proposed in this thesis,including the allocation of power and spectrum resources in the time domain.In this scenario,secondary users get their own transmission opportunities through cooperation with primary users,but there will be selfishness in the forward process.In order to solve this problem,take the situation of user participation into consideration,the assisting power and relay channel conditions are considered comprehensively to mobilize the enthusiasm of secondary users under the conditions of satisfying the basic performance of the system.The optimization problem is modeled and solved by convex optimization theory in this thesis.The simulation results show that the reasonable resource allocation can improve the performance of system.In addition,not only a resource allocation scheme based on energy efficiency optimization for multiple secondary users is proposed,but also the spectrum and power transaction model are studied in this thesis.Besides,the system is also modeled and analyzed.The allocation scheme emphasizes the autonomy of secondary user system,the secondary users have the right to reject the assistance applications that are not conducive to the performance of system,and select primary users who are beneficial to their energy efficiency to assist.The theoretical solution of the scheme is given,and then the frequency spectrum and power are optimized to maximize the energy efficiency of secondary system under the basic requirements of primary users.Finally,the simulation results show that the reasonable resource allocation scheme can improve the efficiency of secondary system in the condition of ensuring the quality of service.